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Articles from 1997 In January


Microcontrollers and the design engineer

Microcontrollers and the design engineer

If you can find a product that doesn't have a microcontroller, wait a year or two--it's sure to have one by then. Even a new electric toothbrush has a microcontroller hidden inside. It sounds a beep to tell you when to move to the next quadrant of your mouth, thus ensuring that you brush all your teeth with equal vigor.

A lot more electromechanical functions are being implemented using microcontrollers, notes Jim Farrell of Motorola's CSIC microcontroller division. For example, you could get a car with automatic door locks 25 to 30 years ago. "The problem with that is you have all these electromechanical circuits, cams, and relays that make it all work, and it's highly expensive and unreliable," he says.

That's where microcontrollers come in. They replace the cam, switches, relays, and contacts with a silicon chip. Silicon performs their functions much better and fundamentally never wears out. The car will wear out long before the silicon.

Microcontroller advantages - Reliability
- Low cost
- High integration
- Space savings
"Thousands of applications are begging to be converted from electro- mechanical to low-cost microcontrollers. Functions that would be done with timers or simple sensors can now be done simpler and less expensively using a microcontroller." Jason Wolfson, design consultant, Lipidex
"Things that move tend to be unreliable. Things that rub against each other tend to wear out. That's where microcontrollers come in. They replace switches, relays, and contacts with a silicon chip, which fundamentally never wears out." Jim Farrell, Motorola's CSIC microcontroller division.
"It's an 8-bit, analog world, and crude precision is enough for many applications." John Wharton, microcontroller analyst and consultant.
"The price/ performance ratio for 32-bit microcontrollers has come down to the point wher the high- performance, servo, and industrial-control applicaitons, 32-bit controllers should be at the top of a designer's list." Lyle Supp, Hitachi microcontroller/ microprocessor division.
"The only difference between a microprocessor and a microcontroller these days is microcontrollers have some variant of ROM on chip, and microprocessor don't." Semiconductor Industry Association.

Microcontrollers range from 4 to 32 bits, meaning they can process that many bits in parallel internally. Wider data and instruction paths let controllers process more complex instructions and run faster. The most popular controllers are the 8-bit parts, which you'll find in cars, appliances, remote controls, toys, pagers, phones, and even industrial applications. Some cost less than a buck.

With the abundance and increasingly lower price of 8-bit microcontrollers of every possible variety on the market, why are people still buying 4-bit microcontrollers?

"Lots of applications require some minimum level of intelligence but not as much as that supplied by an 8- or 16-bit controller," says Scott Gaw of Toshiba's microcontroller division. "The 8-bit market is the largest, but the second largest in terms of units is the 4 bit."

Such applications used to be manually controlled, such as thermostats. Now, microcontroller-based units let you program your home thermostat instead of setting manual switches. Another big consumer of 4-bit microcontrollers is the appliance market, which uses them for dishwashers, ovens, microwave ovens, and sophisticated coffee makers.

Prices for 4-bit controllers range from 50 cents to a couple of dollars. Some of the 8-bit parts are starting to come down in price, says Gaw, because the silicon vendors are starting to strip out some of the peripherals, such as memory and timers, so they can compete with the 4-bit parts.

Designers on a budget need to decide whether they need the processing power of 8 bits or the greater peripheral mix they can get with a 4-bit controller.

Peter Tam, an engineering consultant with Irvine, CA-based PTI, is such a designer. He uses the TMP47/TMP470 series of Toshiba 4-bit microcontrollers for irrigation timer systems.

Some old systems use the 60-Hz line frequency to rotate the motor on a certain time interval. An electromechanical contact switch acts as a time set, triggering a sequence of events. In this case, it turns on a sprinkler valve.

Why replace this simple system with a microcontroller? Tam answers with two words: cost and flexibility. He chose a 4-bit part because it could handle the job and was less expensive than an 8-bit alternative.

"The electromechanical system is limited due to a sequential linear event. Only one thing can happen at a time. And it's very cumbersome. If you want to implement any schedule, you need more features," says Tam. One of his designs implements a real-time calendar, so users can program it to water only on the odd or even days of the calendar. They can also program the system to water different parts of their lawn at different times. You can't do either of these with an electromechanical timer.

"With synchronized-motor applications, you need a lot of related components, and they're all hardware and they all cost something. They also take up more real estate," says Tam. "With a single-chip controller, a lot of features are already built in--output functions such as the triac or relay driver and interface functions such as the LCD driver."

Also, the microcontroller can run on batteries during a power outage to keep the data and programming alive, Tam points out. An electromechanical timer would be off, and the time would be shifted when the power came back on.

Tam stored the software program in ROM firmware, and uses RAM to store temporary data. A programmable timer has a rain delay feature, which lets users enter a number of days--say, 3--and not water for three days but then restart the schedule on the fourth day. With an electromechanical system, the user would have to remember to turn the system back on. "With ours," says Tam, "you set it and forget it."

"The hurdle in irrigation is trying to educate users that using a microcontroller is OK and that it will save them money," notes Tam. He might start using 8-bit controllers for higher-end applications that demand more functions, such as watering parks, school yards, and golf courses.

Notes Toshiba's Gaw, "I see some upward migration from 4 to 8 bits from customers who need to upgrade to 8 bits to add features to compete in their end market. But there will always be a market for 4-bit controllers.

8 bits dominate. The majority of microcontroller applications are still 8 bit, and the 8-bit market is growing, according to Motorola's Farrell.

"As the price of 8 bits goes down, a lot of 4-bit applications will move to the 8-bit chips," he predicts. "You get more processing power at no penalty in cost."

One vehicular application that uses a Motorola 8-bit microcontroller is a tilt-sensing module for trucks delivering containers to ships. A crane lowers a device called a spreader, which attaches to the container and moves the container from the tractor to the ship.

The cranes are enormous and lift objects at 600 ft/min. In some instances, the longshoreman working the ship forgets to detach the container from the tractor. In this case the crane lifts up both the container and the tractor. Because the cranes are so powerful, before anyone has a chance to do anything the container, tractor, and unfortunate tractor driver are hoisted high into the air.

Obviously, this puts the tractor driver at great risk. Typically significant property damage also occurs to the tractor.

The CATL safety system from Equipment Safety Systems, Carson City, NV, uses the Crossbow Technologies, San Jose, CA, CXTILT02 tilt sensor, which in turn incorporates an Analog Devices ADXL05 silicon micromachined accelerometer and a Motorola 68HC11 microcontroller.

The sensor module sits in a heavy-duty enclosure on top of the tractor. When a crane lifts the tractor from the ground, the sensor measures the angle with respect to Earth's gravity. When the angle exceeds 1.5 degrees --which corresponds to the back tires of the tractor being lifted approximately 3 inches from the ground--the system fires a high-power strobe light. The cranes have a light detector that can see the strobe light and automatically deactivates the crane's upward hoist. The crane operator then knows to lower the container.

The accelerometer has a dc output, which goes to an on-chip A/D converter. The resulting digital signal goes to the CPU, which runs an embedded program to calculate the tilt angle of the tractor at all times. The controller also monitors the magnetic sensor connected to the tractor's drive shaft. Whenever the tractor is moving, the sensor ticks along making little pulses. The pulses deactivate the alarm so there are no false alarms from bumps.

After calculating the tilt angle, the controller triggers the output alarm, if necessary. Because of the solid-state nature of the sensor, the entire design fits on a 2x3-in. double-sided pc board.

In addition to inputs, outputs, and the A/D converter, Mike Horton, Crossbow president, used the SCI (serial communications interface) peripheral to enable technicians to hook up a laptop computer to the sensor to do diagnostics.

Horton chose the Motorola chip because he only needed 8 bits of processing power and was already familiar with the architecture. "The real bottom line here is that we've done a million designs with the HC11, and we have a library of code already written for it," he says.

Also using Motorola microcontrollers is a European car company that plans to put 10 68HC08s in each 1999-model-year vehicle: One in each door that controls the locks and the windows, one in each front seat that controls the position of the seat and remembers who sat in it last, one in the trunk that controls the CD player and lights in the trunk and rear tail lights, one in the dash that controls the instrumentation cluster, one in the radio that controls the front end of the audio system, and one in the sunroof that controls it and remembers how drivers like it positioned. The controllers can communicate via a CAN bus.

This kind of scheme is actually cheaper than using wire to make all the connections, notes Farrell. "Wire is not only heavy and unreliable, it's also very expensive."

Bowling for data. The oldest microcontroller of them all is the 8-bit 8051 architecture. It's almost 20 years old now, with more than a billion units sold worldwide. Intel offers 64 flavors, Philips 101, and Siemens 24.

"It's an 8-bit, analog world, and crude precision is enough for many applications," claims John Wharton, a microcontroller analyst and consultant--and the designer who suggested the 8051 architecture 18 years ago.

A recent design that takes advantage of an 8051--in this case, the Philips 80752--is a bowling-ball data-acquisition system. It's the brainchild of Don Hake, project engineer at Red Lion Controls, York, PA.

"There's really no way for bowlers to ascertain how consistent their throwing is or what kind of changes they're making and whether they're successful," says Hake.

People apply three variables to the ball: speed, spin, and how far down the lane he or she hurls it. "It occurred to me, how could you measure these parameters? If I were in the ball I could count rotations, measure how fast it's going, and see how far down I hurled it," says Hake. So he came up with the idea to put a sensor in the ball instead.

Actually, the design has two sensors. One is a plastic piezo film sensor that registers a voltage when the bowler presses on it. That's used both to indicate when the bowler releases the ball and when it hits the lane and hits the pins. A photosensor detects light when the ball is rolling down the lane. Ambient light comes through the finger hole at different angles to generate a rough sinusoidal waveform that corresponds to the speed of the ball.

For such a design to be feasible, it has to be easy to install and go in a conventional bowling ball hole. Many high-level bowlers use inserts in their finger holes. They're made of soft rubber and fit into a standard-diameter round hole. Hake's module fits in that hole. The piezo film slides down between the insert and the hole. When the bowler is holding the ball, a finger is in the hole pressing against the film. When he or she releases the ball, the film generates a voltage pulse that starts up the module.

Hake says the Philips 80752 is one of the smallest microcontrollers around. On-chip peripherals include an A/D converter and 128 bytes of RAM to hold the program. The controller stores data in 8 kbytes of external EEPROM from Microchip, which is enough for a whole game's worth of data.

A laptop PC does the actual data analysis. It uploads the data from the system's LEDs using an IR wand attached to the laptop's serial port.

Says Hake, "It's made a big difference in my game." The module is not yet available, but Hake is in talks with several interested manufacturers.

Fool-proof fans. Another popular 8-bit microcontroller is the PIC series from Microchip Technology, Chandler, AZ. Lipidex (Duxbury, MA) used the PIC16C54 to design the AiretrakTM mobile-home fan controller for Tamarack Technologies, West Wareham, MA. The unit is also popular in the general housing market for bathroom ventilation fans.

The fan goes on at a low rate for a set period of time to periodically change the air in the house. An override button lets homeowners run the fan at full speed. Before this product, people would have to remember to turn the fan on--and mobile homes can get mighty stuffy.

"The PIC16C54 was perfect for this application," says Jason Wolfson, a design consultant at Lipidex. "It had enough capabilities, I/O pins, small size, and low power consumption." Wolfson says he uses the low-power capability to run the system off a battery during power failures, uses the outputs to drive LEDs and triacs, and uses the inputs to read switches. The chip has 512 bytes of program memory and 25 bytes of RAM.

Airetrack keeps time by reading the ac line--120 zero crossings make up a second. The output controls a triac to turn the fan on and off 120 times a second, varying the timing for speed in 16 steps.

"The microcontroller controls the turn-on voltage so that the fan turns on gently so you don't hear it turn on from the living room," says Paul Raymer, vice president at Tamarack. "The big advantage for us is that the electronics fit into a standard switch box, and the wiring's really simple. It's the least obtrusive way of providing ventilation that users won't defeat." In fact, the unit is designed to run 20 years without anyone touching it.

"One of the things that makes the design robust is the watchdog timer," says Wolfson. "I kind of think of it as a timebomb. If it doesn't get reset, it explodes and the microcontroller gets reset." When he wrote the software, Wolfson made sure to reset the timer in certain places in the code so the "bomb" wouldn't go off.

Static potential from users or spikes on the power supply could cause the microcontroller to "crash." Should it crash, the watchdog timer will go off within 2.5 seconds, and the consumer would never know anything had happened.

Wolfson also used a PIC microcontroller to design a mosquito trap for entomologists. The pests come out as soon as it gets dark, but go away after about four hours and don't come out if it's colder than 50F. The previous electromechanical design detected when it got dark, opened up the trap, turned on the fan and a light that attracted the mosquitoes, and ran all night. The fan blew the mosquitoes into a bag and prevented their escape.

"We put a PIC into the device, and we can now program it to go on at dusk and then shut off after 4 hours to conserve battery power," says Wolfson. "We can adjust how the light flickers and how much CO2 gas--which attracts mosquitoes--is sent out."

Fries for 16 bits. Something else that attracts mosquitoes and other flying pests is fast food--like french fries.

Delta Computer Systems, Vancouver, WA, uses 32 microcontrollers from Advanced Micro Devices in the ADR--automatic defect removal--machine. French-fry makers--companies that slice up potatoes and sell them to fast-food chains and grocery stores--use the ADR to scan potato strips for spots of rot.

Each machine has 32 lanes with belts 13/4 inches apart; each lane has a 16-bit, 40-MHz Am186TMEM microcontroller, a scanner, and two knives. Two ADRs interface to a Windows NT master computer.

Company president and ADR designer Peter Nachtwey describes the process: "Potatoes get skinned up line. Then they get shot from a water cannon and through a grate, and they come out as french fries. The strips go through machinery that aligns them end to end and removes the water."

Next, the aligned strips go down the ADR lanes and underneath the scanners. LEDs and photosensors scan each pre-french fry for colors corresponding to rot. Once a bad spot shows up, a microcontroller notes the location and runs an optimization algorithm that figures out the best way to cut the rot out without wasting valuable potato.

Say the ADR finds a 2-inch defect. It's programmed to cut it into chunks of less than an inch so that they fall down a grating downstream.

"Half the trick is cutting the fry without moving it in relation to the belt," says Nachtwey. The goal is to make the cuts as accurately as possible to minimize waste. Before such machines, fry makers "used to have as many as 50 ladies with paring knives on either side of a conveyor belt cutting the rot out of the potatoes--before they were strips," Nachtwey says.

Delta says it chose the Am186EM controller--part of the popular x86 processor family--because it was fast enough so that they didn't have to add a DSP. And, it has the high integration DSPs don't normally offer. Before, the designers would team up a DSP and a slower 186.

Each controller gets scanning data from external memory, processes it, controls the knives via outputs solenoids, and communicates results to master computer via its serial communication port.

AMD's Rob Stintz points out that the controller has an 8-bit external bus and 16-bit internal bus. "This architecture makes the controller less expensive and you can use a cheaper form of memory with it," says Stintz. He does concede that it can be a bit of a performance bottleneck at times.

The master computer stores parameters for 64 lanes, keeps track of data, and calculates statistics. "We tally all the fries to a 16th of an inch," says Nachtwey, "all the fries that come in and all the ones that go out." Because they know how many sixteenths of an inch it takes to make a pound for a particular-width fry, the computer can make reports of pounds per hour and calculate waste. It also does histograms on fry length. "If the fries end up getting short, MacDonalds doesn't like that," he notes, "so the company can input bigger potatoes."

The need for speed. Some problems can't be solved by using bigger potatoes, but more bits can definitely help microcontrollers tackle more complex tasks.

"Thirty-two-bit processors are faster and more accurate," says Lyle Supp, microcontroller/microprocessor product marketing manager for Hitachi's 32-bit SH1 Series of RISC microcontrollers. "If you only have an 8- or 16-bit chip, and the arithmetic you're doing requires higher precision, you'd have to do multiprecision arithmetic, which sacrifices performance. Instead, you could use the native instructions on a 32-bit RISC chip to handle the operations in a single cycle."

Electromechanical applications requiring 32 bits include: hard-disk drives, CD-ROM players, and DVD players. The performance requirements, access times, and accuracy with which you're moving the servo motors or linear actuators demand 32-bit power. More bits allows better accuracy and higher speed because of faster, more precise calculations.

Electronic applications include digital still cameras, home video-conferencing systems, car-navigation systems, and PDAs. The camera and video system make use of MAC (multiply and accumulate) instructions to do DSP-like algorithms, such as image smoothing during zoom.

"The price/performance ratio for these processors has come down to the point where for high-performance, servo, and industrial-control applications, 32-bit microcontrollers should certainly be at the top of the list for consideration," says Supp. Even if a designer could get away with a 16-bit controller, he suggests considering the 32-bit chip first because of the added processing power, and sometimes there's little price difference.

Another 32-bit advantage: If designers want to build a line of products, they could create higher-end products without having to change processor families. Typically, 8- and 16-bit families are starting to run out of steam, according to Supp. With 32-bit chips, designers can start removing hardware from a system and upgrading it just in software. "This tack makes designing much more flexible, less expensive, and more reliable," he says.

Taking this tack is Englewood, CO-based Echostar. Company designers used the 32-bit MIPS R3041 from Integrated Device Technology (IDT), Santa Clara, CA, to power its Echostar digital satellite receiver.

Why did they pick the R3041? "Bang for the buck," answers system architect Dave Kummer. "It was the lowest-cost solution we could get for the highest performance."

Another reason is the on-chip cache and cache controller, which let the designers use a low-cost memory subsystem but still get good performance. The 32-bit cache controller can get data out of the 8-bit-wide external memory and deliver it to the processor at 32 bits wide. Without the cache controller, the designers say they would have had to use wider or faster memory, which is more expensive, in order to get the same performance.

In the receiver, the controller manages the external MPEG decoder chip, telling it when to start and how to display the data. It also runs the Electronic Program Guide (EPG) by drawing all the graphics and managing the TV-program database.

"We could have done it with 16 bits," claims Kummer, "but the advantage with 32 is that our graphics are much faster than what we could achieve with a 16-bit part."

"Because we went with a 32-bit RISC chip instead of a 16-bit CISC chip, our performance is very much higher for the user interface. And," says Mark Jackson, VP engineering, "we pay less for that part."

The company plans to move to a 64-bit in the future as competitive pressures force them to improve the graphics performance even more. A 64-bit controller would also let designers increase the number of colors in the EPG. "As you up the number of colors, you need more processing performance to be able to even maintain the same speed," says Kummer. "Right now, we're at 4 bits per pixel to get 16 colors, if we went to 8 bits per pixel, that's twice as much memory you have to manipulate even if you were going to draw the same picture."

The designers say that when they move to 64 bits, they'll stay with the MIPS architec-ture because of the time and money they've already invested. And Kummer adds that another reason they chose the MIPS architecture is that it's available from a number of vendors and as an ASIC core. "We could get higher levels of integration--such as integrating the MPEG decoder chip onto the processor--by using ASIC technology with this or another MIPS core," he says.

Alan Heimlich from IDT's microprocessor division says the primary advantage users derive from the R3041 is the ability to replace dedicated system hardware with software functions. "That is such a benefit," says he. "For example, you won't have hardware modems in a few years, it'll all be done in software. The cost will come down, software doesn't take up space or burn power, and it will be easier to add more features."

Of course, software almost always has a few bugs. By implementing hardware features in software, users will be able to fix problems by downloading revised software--something you can't do with a broken modem.


Glossary

A/D converter (analog-to-digital converter)--Circuitry that converts an analog signal into digital data that a microcontroller can directly process.

ASIC (application-specific integrated circuit)--A processor whose circuitry is designed by the end-user for a specific task.

CISC (complex-instruction-set computer)--A processor that has variable-length instructions.

D/A converter (digital-to-analog converter)--Circuitry that converts digital data into an analog output.

DSP (digital signal processor)--A high-speed microprocessor designed to perform computation-intensive digital processing algorithms in real time.

EEPROM (electrically erasable programmable ROM)--Memory that can be reprogrammed byte-by-byte electrically. Thus, data in EEPROM can later be changed by a manufacturer or a product's end-user.

External bus--The circuitry that lets a microcontroller communicate with the outside world. External buses are usually 4, 8, 16, or 32 bits wide.

Flash memory--A type of reprogrammable memory that can be erased and reprogrammed while on a circuit board. This memory is organized into blocks comprising many bytes, so erasing or reprogramming one byte affects an entire block. Microcontrollers with on-chip flash have just recently become available.

Internal bus--The circuitry that a microcontroller uses to communicate with its on-chip peripherals. Internal buses are often the same width as a microcontroller's external bus, but sometimes the internal bus is actually twice that bit width.

Microcontroller (also MCU, muC)--A microprocessor with added memory and peripherals. A microcontroller contains the essential functions of a computer on a single IC and is programmed to perform a limited number of functions.

Microprocessor (also CPU, muP)--A silicon chip that is reprogrammable and takes care of central processing functions.

Parallel port--An input/output structure that transfers several data bits in a single operation.

Peripheral--A piece of circuitry on a microcontroller that performs a specific function, thus offloading the main processing block. Examples include timers, memory, I/O ports, and A/D converters.

PROM (programmable ROM)--Also known as one-time-programmable ROM, this kind of memory comes from the chip supplier unprogrammed, allowing an OEM to program each chip individually. Once programmed, however, it cannot be reprogrammed.

RAM (random-access memory)--Read/write memory that stores temporary data while a system is operating.

RISC (reduced-instruction-set computer)--A processor with a relatively small set of fixed-length instructions. RISC processors have pipelines with several stages for decoding and executing instructions.

ROM (read-only memory)--Memory that holds permanent programs and data and cannot be reprogrammed.

Serial port--An input/output structure that transfers data one bit at a time.

Timer--A peripheral that performs routine time-measurement functions, such as producing time delays or counting external events.


Cyber contacts

The following companies can be reached via the Internet. Please tell them you were referred by Design News.

Advanced Micro Devices: http://www.amd.com

Analog Devices:
http://www.analog.com

Crossbow Technologies:
http://www.xbow.com

Hitachi America Ltd. : http://www.hitachi.com

Integrated Device Technology (IDT): http://www.idt.com

Intel Corp.:
http://www.intel.com

Microchip Technology Inc.: http://www.microchip.com

MIPS:
http://www.mips.com

Motorola Semiconductor Products Sector : http://www.mcu.motsps.com/bu/mctg/mctg.asp

Philips Semiconductors: http://www.semiconductors.philips.com

Siemens:
http://www.sci.siemens.com

Toshiba:
http://www.toshiba.com

Also, here are some other Web sites that will prove useful to microcontroller users.

Microcontroller Primer and FAQ:http://dvt07.fagmed.uit.no/faq.
Microcontroller.ht
ml

MCU/MPU Internet Resource List: http://www.cera2.com/micro.asp

CPU Info Center: http://infopad.eecs.berkeley.edu/CIC/news/


Microcontroller or microprocessor?

There seems to be no standard test to determine whether a chip is a microcontroller or a microprocessor.

Many in the industry say a microcontroller is a microprocessor that has memory and input and output structures on chip. The Semiconductor Industry Association insists that a processor isn't a microcontroller unless it has some variant of ROM on board.

However, many microcontroller families include members with no memory at all, and these chips are still called microcontrollers. Also, some industry sources say that microcontrollers range from 4 to 16 bits, some say 4 to 32 bits, and others say 64-bit microcontrollers are possible using ASIC technology. ASICs are silicon chips whose circuitry users design themselves. An engineer could choose to base an ASIC on a microprocessor core and then add memory, inputs, outputs, and peripherals.

What to do? Says Motorola's Jim Farrell: "From a technical point of view, there's no reason to use a microcontroller instead of a microprocessor. The decision is strictly a financial one."

You could take a 6800 microprocessor and add RAM and ROM chips and an I/O chip and you'd effectively have a 68HC05 microcontroller, he says. The problem is you'd have seven or eight chips on the board instead of one.

High-chip-count designs have many negative implications, including being more expensive and taking up more valuable space. Also, reliability is inversely related to the number of pins that go on a board. So by reducing your pin counts, you're actually dramatically increasing your reliability.

A microprocessor would be the right choice if you're going to be using external memory chips in huge quantities. Computer applications need tens or hundreds of megabytes of RAM, and you can't get that on a microcontroller. Also, notes Farrell, some microprocessors, like the PowerPC, have so much processing power on them that the die would become unwieldy and large if you put the memory on the silicon.

Microcontrollers are finding their way into almost every electronic product imaginable. Just this year, the number of controllers in an average new car exceeded the number of controllers in the office.

From workstation to supercomputer, block by block

From workstation to supercomputer, block by block

Mountain View, CA--It's a simple enough idea: Create a computer system that can be pieced together like building blocks. So, instead of making many different machines of all different sizes--workstation, minicomputer, mainframe, supercomputer--you have modules.

Need a workstation? Buy one module. Need more power? Buy more modules, and stack them. And from a manufacturing standpoint, the factory turns out more units of a single product, instead of smaller numbers of different products. That's the theory behind the Silicon Graphics Origin2000, which can go from a deskside cube holding from 1 to 8 processors, to racks of such cubes using more than a thousand. "It's something quite a bit different than they've had in the past," says Peter Lowber, an analyst with DataPro. "I think it's very interesting."

The project quickly became known as "Lego" around SGI. "Two of us even independently went out to Toys 'R' Us and got the same Lego kits," Product Designer Jim Ammon recalls with a laugh. One designer even used them to help visualize a 512-processor system.

But while the concept may be basic, engineering implementation was daunting. How do you connect multiple processors so they act together as one, access the same memory, and move data around as fast as one powerful CPU? It's not terribly difficult with two processors; four is also common. But when you start tying together 16, 32, or 64, connectivity problems mount. "Taking modular workstations and building a supercomputer out of them by cabling them together was a new concept," says Product Designer Richard Singer.

As workstation modules mount, cables not only run between neighboring racks, but also from top to bottom diagonally. "It's quite a cabling nightmare," he sighs.

There were electronic and architectural issues to be solved, of course; but also an unusually tough number of mechanical challenges. "It's not always that a computer relies so much on mechanical design," according to Sally Abolitz, product designer. "We got to flex our muscles more than we usually do."

Tools for design Computer hardware: Silicon Graphics systems
CAD: Pro/ENGINEER
Additional design: AutoCAD, Alias/Wavefront
Analysis/CFD: Fluent and SDRC
Key design problems
- Channeling data among different system modules as fast as if they were within a single machine; SGI uses a special CrayLink cable that speeds data among the modules
- Large amounts of cables to control; engineers developed cable guides within the system's rack
- Heat from powerful processors; heat sinks, multiple fans, and mechanical design channel air flow
Partners in design AMP, Harrisburg, PA--cable connectors
Fabricated Extrusions, Modesto, CA--ABS extrusions, co-extruded thermoplastic elastomer
Gore, Milpitas, CA--cable technology for the CrayLink
IBM, Endicott, NY--CPOP technology
Moto Development Group, San Francisco--detail design of deskside plastics and some small plastic parts
PTA Corp., Longmont, CO--aluminum tooling for most plastic parts
PMP, San Jose, CA--sheet metal production
Taylor and Chu, San Francisco--industrial design
Tuscarora, Colorado Springs, CO--development of shipping pallet and sled for deskside enclosure
IMPACC, Redwood City, CA--rack plastics design and extrusion detailing
Surface Line, Cupertino, CA--rack sheetmetal design and plastics detailing
Werner Company, Greenville, PA--custom aluminum extrusions
Knurr, USA, Simi Valley, CA--off the shelf rack extrusions and castings
P.K. Selective, Santa Clara, CA--custom color anodizing
TIMELINE
FOR DESIGN
April 1994
Early concepts emerge, including several "flavors" of the basic chassis with 2,4, or 8 processors.
August 1994
SGI begins evaluating outside design firms. Engineering team members begin training on Pro/ENGINEER.
September 1994
Engineering team members begin visiting customer sites to understand customer requirements for a new system.
October 1994
Acrylic mockup of chassis assembled for conceptual review and airflow testing.
January 1995
Internal mechanical design review.
March 1995
Foam models submitted to Marketing for approval.
April 1995
First sheetmetal chassis received.
June 1995
Change to wide-chassis design; rack concept developed.
October 1995
Detailed hard model of final deskside unit received and approved.
January 1996
Preliminary databases for plastics submitted to toolmaker.
May 1996
Final chassis prototype received.
August 1996
Initial tool tryouts for plastic parts complete.
September 1996
First racks and deskside units begin shipping.
Silicon Graphics teamProduct Design and Industrial Design Team: Sally Abolitz, Dilip Amin, Jim Ammon, Will Anderson, Demick Boyden, Dan Farmer, Suzy Jones, Michael Koken, Dave Lima, Ali Mira, Brad Morrow, Gene Nicholas, Dave North, Richard Singer, Steve Smithson
Board Layout, Compliance and Product Design Support: Gary Brandenburg, Rick Dachauer, Zin Dolgonosov, Jay Elayda, Michael Falk, Bruce Garrett, Mark Imamura, Tom Jackman, Norman Lee, Keith Miyasaki, Minh Anh Nguyen, Gil Noennick, Paul Pechiu, Frank Usuki, Greg Schaem, Edwin Susbilla, George Tang, Rick Tolentino, Vickie Trip, Ted Wong
Product Design and Program Management: David Alexander, Dana Bailey, Steve Dean, Ed Freige, Tony Roaque, Tim Werness

The resulting system features an Origin2000 cube that can hold up to four processing cards, with one or two processors per card. For the modules to stack, their outer "skin" is popped off and they're placed in specially designed racks.

The racks themselves incorporate new CrayLink Interconnect technology, allowing high-speed data flow among the processors, and a distributed directory system for sharing memory. All this makes it possible for cubes tied together to act as if they were a single, high-powered supercomputer, SGI engineers explain.

Connecting conundrum. One thing the engineers quickly discovered when developing the Origin's Scalable Shared-memory MultiProcessing (S2MP) architecture: conventional connectors for the components wouldn't do. "We're used to tolerances of 30 or 40 thousandths of an inch," she says. "This is three thousandths of an inch."

The design team decided to use CPOP flex-circuit technology from IBM, using tiny dendrites--almost like microscopic Brillo pads. The tiny balls have low impedance and offer high-speed signaling, helping the high-speed modular design so systems can grow "in a seamless fashion," Singer explains. "Without this connector, you can't have high enough speeds."

The major issue: how to make sure plug-in components matched perfectly enough so they would properly blind mate. "This was thehot issue," according to Abolitz. "There was a lot of pressure to get that solved."

For one card, with the node's electronics, SGI designers ended up using long screws to pull the card in so it would fit perfectly into place. And for another card, governing data input/output, a cam and hook on the card's underside ensures it is properly guided.

Stack 'em up. Inside the deskside modules themselves, there would be no cables connecting electronic components. "This was a big leap forward for us," Singer says. "We had cables up the ying yang in our previous systems." Instead, everything would be blind mated.

That cut out cabling between most components within each module; but cabling betweenthem is considerable. There are up to 16 cables between racks for a 128-processor system; and the cables themselves are heavy and thick. The cables use proprietary technology developed by Gore, with delicate insulation that can be damaged if the cable has less than a 1.25-inch bend radius.

What to do with the mass of cables coming out of every module on a large system? Based on the computer's architectural design, there can be only a 3-meter-long cable between any two points; and the system can theoretically hold up to 1,024 processors (SGI can currently ship systems with 128 processors, eight racks tied together plus a ninth "metarack;" soon 256-processor systems will be available).

Special large cable-guiding systems along the front sides of the rack feature helical moldings that snap in a track that is integral to the rack frame's structural extrusions. The hollow extrusion also serves as a cable conduit. This same extrusion features a recess that captivates large, vacuum-formed side panels.

"The side has no fasteners," Singer notes. "It's like the reverse of a Tupperware top, peeling in or out of recesses.

"All the functionality is in the feature-rich profiles of the extrusions," he explains. An ABS extrusion snaps onto the bottom of the rack, indexing the side panel vertically.

As the design deadline approached, Singer admits, "I was a little nervous about the extrusions. I'd never used them before on a product, and I went wild with them on this one."

The first physical model of a rack's cable-management system was done using cut lengths of PVC drainpipe, with hemp ropes substituting for the masses of cable. The subsequent prototype used a Cubital modeling system and actual CrayLink cables. "That was a day of big surprises," Singer recalls. "The prototypes were brittle, things were cracking left and right. I was gluing my fingers together with super glue." However, while the prototyping session may have been nervewracking, the design worked fine in actual production.

For the first time, SGI used a technique called V-Process from Harmony Castings, Harmony, PA, to create large, complex, low-volume parts for the system. Die casting is typically used for this type of part, but time was of the essence for producing the card-guide "cage" to help house printed circuit boards.

V-Process heats a thin plastic film and puts it over a pattern, which is then surrounded by a flask filled with sand. The sand is vibrated so it tightly fills the pattern. A second sheet of film goes over the flask, a vacuum draws out remaining air, and a completed mold is stripped from the pattern. Harmony then pours aluminum into a mold created this way; as long as the mold is held together in the vacuum, it keeps its shape. After the mold cools, the vacuum is broken, and sand and completed castings fall free.

Each resulting V-Process part costs about five times more than conventional methods, but the tooling is one-tenth the cost--ideal for low volumes. Most important: Production took only five weeks, compared to an estimated 20 weeks for conventional die casting.

The deskside system's top consists of plastic, while the bottom includes sheet-metal components that mate with a special pallet used to move the system around the manufacturing plant. The pallet stays with the system during final shipment, when it serves as a "sled" to slide the module onto its proper site. Cushion packaging is shaped to double as a ramp, for final sliding off the pallet.

Appearance is also important for a company like Silicon Graphics, known for generating dazzling computer displays and systems for high-profile entertainment-industry users. Engineers say a great deal of attention was paid to industrial design; and it turned out that ID and mechanical needs often fused to create a single solution. "There is a lot of blending whether something is mechanical or cosmetic," Ammon says.

He worked on designing the front door to the module--important to allow easy access to the system while also keeping the stylized look. "Eighty percent of the design time was spent on that one side," he says. The final decision: a door that would slide up and down, not open out, so there'd be no worry about it breaking off. Traditional rods and gears can cause such doors to stick; instead, the door has gear racks on both sides, which engage a gear and rod mechanism forcing both sides of the door to slide in unison. A constant-force spring and damper give the motion a constant speed. "The entire door is the actuator," he explains. This prevents rack and bind problems inherent for a door wider than its length.

Structure and heat. SGI designers used Fluent and SDRC analysis pack-ages to model a large multi-fin heat sink. Pro/ENGINEER was tapped for most of the basic CAD work.

To keep the module strong while allowing access to the system from both sides, engineers designed in a "midplane," instead of a conventional backplane, so the cube could open from either side.

Customer demands forced a major revision to the design. A year into the project, the idea of a narrow, 4-processor building-block module was scrapped because it wouldn't fit into standard-sized 19-inch racks, or have enough I/O and flexibility. With half the time gone, engineers were suddenly faced with squeezing twice as many processors into a different-sized box--and no extension to their deadlines.

"Previous design directions were scrapped," Ammon recalls. "Some me-chanical concepts were adapted from the previous chassis design."

Out the door. SGI engineers worked through the summer to finalize the design--it wasn't until August that one of the card connector issues was finally hammered out, just weeks before the system was to ship.

They also worked with a bevy of outside companies to jointly develop various portions of the system. "We worked with all our partners in a collaborative environment, rather than a 'go away, and come back with a design' approach," Ammon notes.

When the Origin finally began rolling out the door: joy, relief, satisfaction. "It's great to work on a project when you have a clean slate," Abolitz says. "It's been fun."


Building a 'hypercube'

The theory behind Silicon Graphics' building-block computing uses multi-dimensional hypercubes. While it's easy enough to visualize a conventional 3-D cube, 4 and more can be tougher to construct. According to a paper by SGI's Jim Ammon, written to help outside consultants understand the project, a technique he dubbed "double and stretch" helps:

Take a familiar 3-D cube, and duplicate it onto itself with connections between the twin vertices. The twin cubes are pulled away from each other, in the direction of the new 4th dimension, stretching the links between twin vertices. The resulting structure is two 3-D cubes with 8 links connecting the common corners between the cubes.

"If we had a 4-D piece of paper, we could have drawn the 4-D cube without any of the lines crossing," Ammon notes. "We cannot construct a true 4-D structure in our 3-D universe, but we can build a system that maintains the same vertex-to-vertex connectivity.'

The 4-D hypercube includes 16 vertices, 64 processors (4 x 16 vertices) and 32 CrayLink connecting cables. When the 4-D cube is "doubled and stretched" again, the 5-D version features 32 vertices, 128 processors, and 80 CrayLink connections. A 6-D version has 64 vertices, 256 processors, 192 CrayLink cables, and so on. Vertices are actually router chips, to which 4 processors (2 node boards) can be connected.


Supercomputer design the way it was

Silicon Graphics' modular design is a major leap from the way engineers built the first supercomputers. The following is an excerpt from The Supermen: The story of Seymour Cray and the technical wizards behind the supercomputer, by Design News Senior Regional Editor Charles J. Murray. The book, published by John Wiley & Sons, will be available in bookstores in February.

Atop a sandstone bluff, in a three-bedroom cottage overlooking Lake Wissota, Seymour Cray wrestled with the design of the CRAY-2. Although few engineers in Chippewa Falls knew it, Cray had never stopped working on the machine. So while the crew in Boulder toiled away at their version of the CRAY-2, Cray continued to work on his.

In 1981 he spent most of his time at the cottage, trying to piece together the mix of technologies that was whirling around in his brain. To help him, he had set up his own design lab there: In one bedroom there was a big Data General computer, a real monster about six feet high, with several cabinets full of electrical racks.

Cray used the mainframe to run the software programs that aided him in the design of the circuit boards for the CRAY-2. With the software, he could lay out a complex array of electronic components and foil lines on the computer screen. Then, if he wished, he could shift the parts around on-screen without having to rebuild the hardware every time he wanted to make a change.

The mainframe helped Cray to improve the design process, but it was not without its penalties. In 1981, CAD was still in its primitive stages. So Cray needed to augment it with dozens of little personal computers, called SuperBrains, that he also kept inside the cottage. At any one time, Cray usually ran software on about half a dozen SuperBrains and on the mainframe. The SuperBrains were scattered all over the cottage--in the bedrooms, living room, and kitchen. Because personal computers were unreliable in 1981 and were constantly fizzling out, he stored extras in the garage and at the Hallie lab, where a technician was on call to fix the duds.

Cray liked the setup at the cottage. With Cray Research growing larger and more successful, the cottage was a safe haven where he could work in blissful isolation for days on end, away from the inevitable corporate distractions, away from the concerns of a thriving business.

Still, the woods around Lake Wissota were a less-than-ideal locale for designing supercomputers. Power outages were commonplace. Cray never knew when the power might crash, causing him to lose hours worth of work, so he installed a utility power system in his garage. He also had to install a powerful air conditioner to cool the mainframe.

None of this deterred him in the least. Nor was he deterred when he decided the operating system on the Data General mainframe wasn't right for his needs. He simply sat down and rewrote thousands of lines of operating system code. Ironically he did all of this--the mainframe, SuperBrains, backup power, air conditioning, and new operating system--to save time. Supercomputer design was such a complex process that an upfront investment like this could help in the long run.

For more on this
technology, go to
www.sgi.com/
tech/whitepapers/
hypercube.asp
l


Value engineering - The right material, in the right place, at the right time

Value engineering - The right material, in the right place, at the right time

Seeking to gain a competitive advantage, OEMs increasingly turn to value engineering to achieve greater productivity and improved cost efficiency, says Jeff Montanye.

Design News: Can value engineering be applied to any industry using plastics parts?

Montanye: Yes, any OEM can benefit from value engineering for materials selection and design. And, because value engineering contributes to significant cost-savings, it can be especially beneficial to manufacturers facing growing global competition, or rebounding from soft market conditions.

Q: What is the goal of value engineering?

A: The goal is to select a material that supplies only the properties required by the application, while making design changes that are virtually invisible to the end user and have no negative impact on part performance. Some people might assume that value engineering is simply a matter of achieving cost control through material selection, but it is more than choosing a cheaper resin. In fact, the actual cost of the resin is only one factor to be considered when conducting a material analysis.

Q: Historically, wasn't value engineering considered by many to be synonymous with "down engineering?"

A: Such thinking led to the misconception that value engineering involved replacing the original material with a less expensive or inferior material. In practice, the new material would be adequate to "get by" in the application, but could potentially compromise product performance. This type of material substitution resulted in inferior end-use products and created the negative attitude toward value engineering that many still perceive today.

Q: How has this changed?

A: Now, value engineering is understood for the true value it brings to an application. It is recognized for emphasizing the use of the right material, at the right price for a given application. And, contrary to traditional thinking, achieving this balance of part performance and material cost can even be accomplished by using a more expensive plastic--as long as the resin helps increase production efficiency, thereby reducing cost.

Due to the competitive nature of some markets, OEMs hesitate to risk changing materials. However, due to recent advances in polymer performance, a look at new material options is merited. By taking a proactive approach to value engineering, manufacturers can now benefit from these material advances.

Q: What are the key benefits of value engineering?

A: Value engineering offers significant benefits to manufacturers in most industries, especially in cost control/reduction and design improvements. These benefits can be attained by determining how to create the best production value for the part. Often, the greatest value is found though material reselection, part re-design, or, better yet, a combination of these two ingredients.

Q: How can value engineering best be approached?

A: Consider using a "stair-step" approach when switching from one resin to another. In this way, the next resin, either up or down the scale of cost/performance, is considered first to better ensure customers' acceptance and satisfaction with the re-engineered product. More significant changes can be made, if needed, by moving into other resin families farther up or down the scale.

Q: What organizational changes are needed to make value engineering work?

A: More often than not, value engineering requires process changes rather than equipment changes. In addition, the skill and knowledge of personnel inside and outside the company should be utilized to investigate all the options. Materials suppliers can provide valuable assistance in the process, from resin selection and cost analysis to troubleshooting and material trials. With proper planning and attention, nearly any OEM can realize the full range of benefits provided by value engineering.

Beyond a simple bond

Beyond a simple bond

Newton, MA--Often a replacement for mechanical fasteners, adhesives seem to have a simple task: bond materials together. But the role adhesives play in product development continues to expand. In many applications, adhesives can now deliver benefits ranging from resistance to impact and hostile environments to improved aesthetics and structural integrity to reduced costs and assembly time.

Take speaker assemblies for example. Thermal resistance has become increasingly important in speaker manufacturing. Over the years, the overall size of speakers has decreased, while power requirements have increased significantly.

These changes have increased operating temperatures and affected the requirements for speaker components, particularly the thermal resistance and heat-aging properties of the adhesives used. As a result, adhesives must now withstand higher temperatures for longer periods of time than ever before.

To address this problem, speaker manufacturer International Jensen Inc., Schiller Park, IL, recently tested Loctite's (Rocky Hill, CT) new PRISM 4204 instant adhesive on its speaker assemblies. The company has used instant adhesives to bond its speaker assemblies for years. However, as thermal requirements increased to 250F, standard adhesives could withstand temperatures of only 185F.

PRISM 4204, a rubber-toughened cyanoacrylate, can endure temperatures up to 250F. It also offers improved resistance to impact, vibration, humidity, and damp environments. And it achieves fixture strength within 20 to 30 seconds on most substrates, curing to a clear, durable bond line.

International Jensen used the adhesive to attach the speaker's flexible components. First, the adhesive was applied directly to the voice coil. To assist the fixturing process and speed the cure, an accelerator was sprayed on the adhesive joint. The spider was then attached to the voice coil. Next, the cone was attached to the voice coil in a similar fashion.

To affix the whizzer to the cone body, a bead of adhesive was applied on the inside diameter of the cone. The joint was treated with an accelerator to speed the fixturing process.

Results of the adhesive test have been excellent. "All of the company's adhesive concerns have been successfully addressed," says Haresh Kapadia, principal polymer engineer at International Jensen, "including workable viscosity and rapid room-temperature fixturing." Most important, the adhesive meets the upcoming 250F OEM requirement.

Broader benefits. Choosing the right adhesive doesn't just improve the product; it can significantly impact the manufacturing process as well. Chris Ervin, plant engineer at Drexel Heritage Furniture, Drexel, NC, knows this all too well.

With processes that can involve more than 100 people to build a single piece of furniture, this industry ranks among the highest for labor-intensive manufacturing. Controlling costs and quality remains a constant challenge.

One of Drexel's most time- and labor-consuming applications involved attaching a decorative, solid-wood panel to a headboard's front facing. The entire process took eight to ten people two days to complete. But by switching to Jet-Weld TE-100 thermoset adhesive from 3M's Industrial Tape and Specialties Div. (St. Paul, MN), the product can now be finished in one to one-and-a-half days--with just two people, says Ervin.

In the original manufacturing method, two people apply PVA adhesive to a poplar overlay panel. Two other individuals position the overlay on a headboard and pin-nail it in place. Next, two workers place the 20-lb headboard flat on an iron-rail track, and stack up to 20 pieces atop each other.

Workers then place a set of top rails, aligned with those below, over the headboards, and roll the unit onto the press. Up to 600 psi of force compresses the headboards. Workers then "bail" the compressed unit using two 150-lb headblocks (one on top, one on bottom) and eight 30-lb turn-buckle clamps (four per side) that extend between the eight 40-lb bottom and top rails. The boards are compressed for one day. This process prevents the poplar panel from bowing and permanently secures the panel to the headboard.

When curing is complete, four workers release the clamps, headblocks, and rails; remove the headboards; and return them to the assembly line where workers counter-sink nails, apply putty, and sand off excess putty. The entire process takes from 28 to 32 hours to complete, including two quality checks.

In addition to time and labor issues, the headboard manufacturing process presented adhesives problems. The conventional hot-melt adhesives the company used reheated in the finishing box and made assembly more difficult.

Making the move to 3M's Jet-Weld adhesive revolutionized the headboard process, claims Ervin. Jet-Weld, a one-part, moisture-curing urethane, has thin glue lines similar to those of PVA adhesives, long open times (up to 10 minutes), and fast set times (1,000 lbs of overlap shear in 10 minutes on maple).

Now, a worker applies the Jet-Weld adhesive to the panel with the squeeze of a trigger on a lightweight pneumatic applicator. Two others place the overlay panel on the headboard, engage four clamps for 30 seconds, and proceed to the next piece. The adhesive eliminates the nailing, the trip down to the press room, the cold pressing and bailing operations, the return trip to the work room, counter sinking, putty applications, and subsequent sanding.

Using Jet-Weld also did away with one quality inspection, two parts lifts, material handling, set-up time, and scheduling problems. The result: reduced production time per part from 28 plus hours to several minutes.

Engineering News

Engineering News

Engineers lead the search for life beyond Earth

Exploratory missions to study Mars, Europa, and signs from other star systems will attempt to answer the question: 'Are we alone?'

Seal Beach, CA--Man has always been fascinated with the possibility of extraterrestrial life. Nearly a hundred years ago, astronomer Percival Lowell, having spotted "canals" on Mars, elevated the topic from the metaphysical to the scientific. Today, renewed interest and funding has thousands of engineers and scientists designing machinery, sensors, systems, and spacecraft for exobiological excursions to several nearby planets and moons, as well as for examination of planets in adjacent star systems.

Much of this interest stems from a series of findings during the past three decades. Viking missions of the 1970s revealed no Martian canals, but returned photos of volcanism and massive surface features formed by water erosion billions of years ago. The Galileo spacecraft sent back startling data about possible liquid water on Jupiter's moon, Europa. And this past August, a team of scientists reported the possible discovery of fossilized microorganisms in a chunk of Martian rock that was blasted from the planet 15 million years ago and landed as a meteorite in Antarctica. Beyond our solar system, scientists estimate, lie about 50,000 Earth-like planets in our galaxy alone.

But "interesting findings" are not conclusive signs of life. To gather more evidence, NASA plans to launch a pair of flights to Mars every two years until about 2005, and Congress has promised $100 million a year in Mars money to pay for them.

Bring it back alive? One such program is the Sample Return Mission. Its goal: retrieve for study on Earth dirt, rocks, and core samples from three locations on Mars. These areas would be selected by studying data from the Mars Global Surveyor currently winging its way towards the planet. Onboard is a thermal infrared spectrometer that will help identify carbonate rock formations and an altimeter to map likely locations of sedimentary deposits.

The first mission would launch about 2003-05, with two follow-on missions at two-year intervals. Each would consist of an advance rover that would spend a year collecting samples. The rover would wait for a lander to arrive, transfer about one pound of samples, and then the lander would blast back to Earth.

Sample Return requires advancements in several areas, including:

- High-impulse, low-mass propulsion systems. "We're looking here for a 20% improvement in propulsion-to-mass ratio for traditional chemical engines," says Dan McCleese, leader of the Mars Expedition Strategy Group for NASA.

- In situ instruments. An example would be a microchip-based capillary electrophoresis instrument for amino-acid analysis that could be etched on glass just centimeters long. NASA's Microdevices Laboratory is working with Jeffrey Bada at the Scripps Institution of Oceanography in San Diego to make such a device.

- Lightweight, low-power excavation tools to get below the planet's radiation-sterilized surface.

- Long-range rovers capable of surviving for years on the surface.

Red rover. Such an exploratory vehicle might look a lot like Marsokhod. Built by the Lavochkin Association in Moscow, the roughly 150-kg rover has an articulated spine and rolls on six individually powered titanium wheels. "It can crawl like a serpent over rocks three feet high," says Daryl Rasmussen, an engineer with Ames' Intelligent Mechanism Group (IMG). Should all go as planned, Marsokhod will first fly as part of the Mars Together Program in 2001.

IMG engineers took the basic chassis and added U.S.-built electronics and avionics to create a world-class planetary rover. A three-joint robotic arm (McDonnell Douglas) can retrieve and manipulate rocks and tools while two of three video cameras, mounted on a 1.2-m tall mast, provide stereoscopic vision and "situational awareness." Camera signals feed through either a Matrox image digitizer for side-by-side grayscale shots, or a StereoGraphics processor to create 3-D color video for view-ing through CrystalEyes VR glasses.

Scientists can "pre-run" maneuvers on a computer workstation with a high-fidelity virtual re-creation of the rover and its environment. "They can perform a task virtually and then send the commands to the rover on Mars," says Rasmussen. With a 10- to 80-minute delay, real-time telepresence isn't possible.

Engineers expect to learn more about the planet's operational conditions from Sojourner, the small rover carried aboard the Pathfinder spacecraft scheduled to land on Mars July 4, 1997. Sojourner contains experiments to measure the effects of Martian dust on solar cells and determine the abrasive characteristics of the soil on machinery.

Watery moon. Mars isn't the only place scientists think could harbor life. On Jupiter's moon Europa, tremendous gravitational tidal forces might generate enough heat to create a liquid water ocean beneath the several-kilometer-thick ice crust. Henry Harris, a Jet Propulsion Laboratory technical staff member, thinks he has a way to sample that ice.

Called Ice Clipper, the proposal involves releasing a 50-kg, spherical, boron-nitride "impactor" from the spacecraft that is racing towards the moon at 8.6 km/sec. Just after release, retrorockets slow the spacecraft enough to miss hitting Europa by about 50 km. The impactor strikes the moon, shooting up a plume of debris that the spacecraft flies through, gathers, and returns to earth.

Refractory materials are captured by embedding them in a retractable panel of thick aerojel-filled pockets, while a sapphire plate coated with magnesium collects samples of volatile material. A shield protects the craft from the high-speed ejecta.

Challenges? Designing a laser pointer to target and track the impact location, and simulating a 19,000-mph impact with supercooled ice. "Nobody has ever tried to sample the surface of a planetary body by hitting it with something," says Harris.

Beyond Pluto. NASA's proposed Origins program, beginning about 2003, is charged with the formidable task of peering outside our solar system for habitable--or even inhabited--planets orbiting stars light-years away. Using a series of long-baseline, space-based interferometers (possibly as large as 1 km), scientists will analyze the spectrum of reflected light to measure the composition of these planets' atmospheres.

As with the Mars and Europa programs, Origins relies heavily on inferences and detective work; nobody expects to see crawling creatures. Says Dr. Firouz Naderi, Origins program manager at JPL: "You really don't have to sit down and split a pizza with an extraterrestrial to know that they exist. You can look for the telltale signs."

Cybercontacts

Center for Mars Exploration: http://cmex-www.arc.nasa.gov/

NASA Ames Intelligent Mechanisms Group: http://img.arc.nasa.gov/

The Origins program: http://www.hq.nasa.gov/office/oss/origins/Origins.asp

Jet Propulsion Laboratory:
http://www.jpl.nasa.gov/

--Mark A. Gottschalk, Western Technical Editor


Chrysler debuts new engine line

Auburn Hills, MI--Employing the aggressive approach that has marked their recent successes, Chrysler engineers have developed a new family of automotive engines in record time.

The company's aluminum V-6 engines, introduced in November, were developed in 98 weeks at a cost of about $625 million. In contrast, typical automotive engine-development programs take about two-and-a-half years and a billion dollars. "We designed these engines in the shortest time in the history of Chrysler and maybe in the history of the industry," notes Francois Castaing, executive vice president-vehicle engineering and general manager of powertrain operations for Chrysler.

The company's new engine line includes three models: a 2.7-l, 24-valve, dual overhead cam V-6; a 3.2-l, 24-valve V-6; and a 3.5-l, 24-valve V-6. The 2.7-l engine will first appear as the standard engine in the Dodge Intrepid and Chrysler Concorde for 1998. The 3.2-l engine will power the Dodge Intrepid ES and Chrysler Concorde LXi, while the 3.5-l will be used exclusively on the replacements for the Chrysler LHS and Eagle Vision.

To speed development and cut costs, Chrysler engineers employed a paperless design process. To accomplish that, they used CATIA-based computer design, predictive modeling technology, and rapid prototyping. They also used a simultaneous engineering process incorporating cross-functional teams from design, engineering, manufacturing and other disciplines. Result: The engines were designed and built in 98 weeks--about 26 weeks less than the norm for automotive engines.

Shortening the development time enabled Chrysler engineers to cut costs. The computerized design process also helped meet future emission regulations. "Because we are efficient and because we are fast, the customer benefits," Castaing says.

--Charles J. Murray, Senior Regional Editor


Little disk breaks data-density record

San Jose, CA--IBM has developed a 2.5-inch disk drive weighing less than 100 grams that packs 1.44 billion bits of data per square inch, company officials announced. Big Blue believes the disk, designed for a new generation of super-slim notebook computers, has broken the previous record for hard-drive data density.

Engineers used magnetoresistive (MR) head technology to design the 1.6-Gbyte Travelstar VP, just 9.5 mm thick. (The Travelstar 3XP hits 3 Gbytes of storage at a density of 1.35 billion bits per square inch.) The MR data-writing head allows data to be written more narrowly than with conventional thin-film inductive head technology; thin film is still used in the drive for reading data. "You want to write narrow and read wide," explains Mark Jones, program director, mobile business line management.

The 99-gram drive is a major weight reduction from the early '90s, when initial 3.5-inch hard drives for the first notebooks tipped the scales at around 300 grams. IBM's most recent 2.5-inch drive weighed 140 grams; Travelstar shaves off another 40.

"Notebook manufacturers want to increase features in a smaller size," Jones notes. "This is one of the contributors." About 90% of IBM's drives are sold to third-party OEMs, he says. dn

For more information on IBM drives, visit http://www.storage.ibm.com.


Truck caps pass tough certification tests

Mansfield, TX--Truck owners have long known the importance of high-performance truck caps that can withstand the rigors of the road and defy even the most demanding off-road terrain. However, until now, truck-cap owners have had to rely only on verbal assurance--or their own "pass/fail" experience--to ensure their truck cap was "tough" enough.

Enter the Brahma Tough Certification program. Introduced by ADUCO International Inc., the program tests truck-cap performance and provides a benchmark for the highest standards of materials and product quality in polymer truck caps. The tests simulate on- and off-road conditions and temperature extremes.

"While the style and appearance of a truck cap are critical, it is equally important that a cap withstand extreme weather conditions and has the strength to endure the jolt, twists, and torque of on- and off-road use," says J. Richard Negrey, ADUCO president. "We needed a material that would meet the Brahma Tough requirements of strength and functionality, while maintaining an attractive, stylish appearance."

ADUCO found that material in Centrex(R) and Lustran(R) ABS resins from Bayer Corp., Pittsburgh. The Brahma Tough tops are formed from a composite sheet of Lustran ABS 130 resin, with a cap surface of protective Centrex 401 weatherable polymer. The sheet, coextruded by Primex Plastics Corp., Richmond, IN, holds the key to creating the tough, yet flexible top that easily conforms to the shape of a truck bed.

The polymer caps are UV resistant, up to one-third lighter than fiberglass tops, and can be recycled, Negrey claims. The caps can be left unpainted or painted to match the color of a truck bed. Not only are they easy to maintain and clean with approved cleaning agents, they have reduced the potential for VOC emissions.

The Brahma Tough tests included a torsion test, during which the sample cap is bounced and twisted for up to 24 hours at room temperature. The sample is then thermocycled for 15 cycles in an environmental chamber that ranges from -40 to 160F over a 24-hour period. It is further tested for impact resistance to simulate the normal knocks a cap takes during loading and unloading materials.

ADUCO and Bayer also are investigating the possible use of polycarbonate glazing for truck caps. A new organic modified ceramic hard coat promises to dramatically increase the durability and abrasion resistance of polycarbonate windows. The material is expected to be introduced in mid-1997.


Computer connectors beat the heat

Harrisburg, PA--AMP Inc. has designed a one-piece, card-edge connector with the same one-to-one signal-to-ground ratio found in two-piece models. The design allows the connector to handle high signal speeds required by today's computer processors.

"As far as we know, AMP is the first to successfully make a one-piece, high-speed, card-edge connection, which is less expensive than the original two-piece connectors," says Jose Domingos, AMP's product manager of card-edge products.

In order to make the design feasible, AMP replaced liquid-crystal-polymer (LCP) materials with injection-molded Ryton(R) polyphenylene sulfide (PPS) supplied by Phillips Chemical Co., Bartlesville, OK. The housing's original design specified the LCP when production began. Because of dimensional instability problems during the high-temperature solder process, however, the LCP gave way to the Ryton R-44 PPS a few months later.

"Our major problem with LCP was its poor high-temperature creep characteristics," explains Doug Sarver, AMP's card-edge products engineering manager. "High-temperature creep is a real concern with connectors having a relatively deep card-slot depth and preloaded contacts."

The LCP-made parts distorted during infrared soldering. The interior walls for the card slot collapsed and prevented insertion of the daughtercard. Rejected connectors were scrapped, resulting in a large amount of costly, unusable parts.

On the other hand, the PPS resists high-temperature creep and can withstand the infrared heat used in surface-mount soldering--240 to 250C--to produce a more dimensionally stable part. Resistance to soldering heat, both wave and surface mount, is one of the many environments that AMP connectors must survive.

For example, the high-speed, standard-edge connectors are tested for long-term temperature resistance by being mated with test circuit boards and exposed to 105C for seven days. The PPS passed these tests without difficulty, and did not distort during the mounting process.

The multi-contact, edge-board connectors are used in high-speed, digital computer systems. These systems have printed wiring boards with two levels of 0.050-inch-centerline gold-plated pads offset by 0.025 inches. The connector's one-to-one signal-to-ground ratio is 40 signal lines per inch, with 500-ps edge rates and less than 10-ps skew.


Giant servomotors replace hydraulics

Rockford, MI--To coil the powerful springs for a truck's suspension, coiling machines must produce tremendous force. That's why most such machines typically use large hydraulic pumps and actuators.

Now, however, one firm has found a better way to coil steel wires for a suspension spring. JM Systems Corp., a maker of wire-forming and spring-coiling machinery, has introduced a spring-coiling system that employs giant servomotors instead of hydraulics.

The dc brushless servomotors, which may be the biggest in the world, power the systems that control the pitch, diameter, and feed rate of the springs. Using them, the machine can coil wire up to 0.75 inches in diameter, and produce up to 1,200 springs per hour.

Achieving such speeds, especially in high-force applications, would have been impossible with conventional servomotors. But the motors used on the new machine combine high torque capabilities with relatively low inertia, enabling the machine to reach higher speeds. "The better the torque-to-inertia ratio, the faster the machine can accelerate and decelerate," explains John Mitteer, president and founder of JM Systems Corp. "And the faster you can accelerate and decelerate, the higher your production rate." The motor's relatively low inertia minimizes overshoot and eliminates the need to take special steps to dampen the overall system, Mitteer says.

Key to the capabilities of the new machine was the development of the giant servomotors. Designed by engineers at Custom Servo Motors, New Ulm, MN, they measure 320 mm across and weigh 568 lbs each. Their peak torque rating is more than 12,000 in-lb and they are rated at 3,500 in-lbs continuous torque. To produce such high torque, the servomotors employ high-energy neodymium iron boron magnets. As a result, the magnets' weight and inertia are far less than they would have been if conventional magnets were used. "A conventional servomotor probably would have had at least four times as much inertia as our motor and probably would have weighed over 1,000 lbs," notes Bill Anderson, president of Custom Servo Motors.

The servomotors apply torque through a gearbox made by Cone Drive Textron, Traverse City, MI. Positioning accuracy of the tools, which must be maintained to 0.001 inches, is accomplished through closed-loop computer control.

By employing electric motors instead of hydraulics, Mitteer says he has eliminated potential noise, contamination, and maintenance problems. The machine will be used to coil springs for domestic automobiles, NASCAR vehicles, and railroad cars, as well as light and heavy trucks.

--Charles J. Murray, Senior Regional Editor


Silicone compound improves heat-resistance

Exton, PA--High temperatures, flame exposure, and molten splash can all mean trouble for industrial cables, hoses, and gas lines. Fyrejacket(R) sleeves and Fyretape(R) wrap from Bentley-Harris protect against such heat-related hazards.

Each product's design employs a substrate of woven fiberglass: hollow tube, filled tube, or flat tape. A specially compounded liquid silicone rubber (LSR) is coated over the top of the substrate and heat-cured. The LSR, from Dow Corning STI, Plymouth, MI, is a solventless, 100%-solids material with low flammability and a high limiting oxygen index.

The low surface energy of the cured elastomer helps Fyrejacket and Fyretape products shed molten glass or metal splash in difficult applications, such as steel mills and foundries. According to Bentley, both constructions are highly resistant to a wide range of solvents, fuels, and oils. And the products remain flexible at temperatures as low as -65F.

Fyrejacket sleevings are offered in two grades. Industrial class resists molten splash and temperatures up to 500F, while the aerospace class protects against short-term flame exposure and temperatures as high as 2,000F.

The LSR coating from Dow is a 30-durometer elastomer developed for use in high-speed injection-molding or extrusion processes. The material can be cured very rapidly and with little flash, holding tolerances and scrap rates low. It offers a 1:1 mix ratio and low viscosity for easy mixing and delivery, even at low injection pressures.

The solventless formulation of the silicone compound forms no hazardous by-products during the additional cure process, minimizing venting requirements and eliminating the need for solvent removal. The material also offers a long pot life of at least 24 hours after mixing at room temperature.


Getting a brake from the landfill

Carbondale, IL--Research-ers seeking ways to use Illinois' estimated 30 billion tons of recoverable coal have come up with some surprising results. For instance, it turns out that the properties of fly ash, a combustion byproduct, make it an excellent material for automotive brake pads.

That's the contention of Vik Malhotra, a professor of physics at Southern Illinois University (SIU). Malhotra's research, conducted under a grant from the Illinois Clean Coal Institute, concludes brake pads made from fly ash have better friction and wear characteristics than brake pads currently on the market.

"The combination of several combustion fly ashes makes the material used in the brakes superior to any synthetic material currently used in brake pads," Malhotra says. "In fact, it would be nearly impossible to duplicate the properties of fly ash for automotive brakes."

Malhotra and his graduate students mix 65 percent fly ash with other combustion byproducts and some non-waste materials. This mixture is poured into molds and allowed to dry. After curing in a hot-water tank, the long timbers are cut crosswise into sections that resemble hockey pucks. The pucks are machined into refined brake pads. Malhotra says this process can be used to produce pads that would retail for $15 apiece, about half the price of a conventional brake pad.

According to the Clean Coal Institute, coal-burning utilities in Illinois landfill three million tons of fly ash and other combustion byproducts annually. The organization funds many projects similar to the one at SIU in an effort to clean up coal's image. Gainful employment for coal byproducts can also be found in road-beds and surfaces, patio bricks, sewer tiles, and flower pots.


Fasteners aim at uninterrupted laptop performance

Melbourne, FL--Paravant Computer Systems' Rugged Notebook (RNB) 510 Series laptop computers operate in temperatures from 0 to 50C. A fully sealed aluminum alloy case protects against dust, dirt, rain, humidity, and salt. The computers are engineered to perform in areas subject to severe shock and vibration as well.

To ensure uninterrupted operating performance under these conditions, every part in each laptop is mechanically strapped, fastened, or soldered. Key to assembling the various components are more than 10 dozen PEM(R) self-clinching fasteners from Penn Engineering & Manufacturing Corp., Danboro, PA.

"Over the years, other fasteners have given me nightmare experiences by failing prematurely," says Walt Rankins, manager of mechanical engineering at Paravant.

The RNB 510 laptops feature five different types of PEM self-clinching fasteners, totaling 131 in each unit. Type PF32, low-profile, steel, self-clinching panel fasteners are installed at 12 external locations in 0.060-inch-thick aluminum. Rankin cites the fasteners' slotted heads, which enable loosening or tightening by hand, as a benefit should service be necessary in the field.

Fourteen Type BSOS, stainless-steel, blind, threaded standoffs support boards inside each unit. Their larger profile distributes pressure more evenly on the boards.

Meanwhile, 78 Type BS, stainless-steel, self-clinching, blind fasteners in four different thread sizes close off the display area and the main pc-board access area, hold the keyboard, and serve as points at the base of the unit that allow the entire computer to attach to a mounting bracket.

Twenty-four Type FHS, stainless-steel, self-clinching flush-head studs serve as alternatives to standoffs. They provide flexibility in mounting internal components without being noticed externally due to their flush-head assembly upon installation. Three Type SOS stainless-steel, thru-hole, threaded standoffs also mount internal components.

All the PEM fasteners bring the strength of threads and the durability of thread-mating surfaces to each unit's assembly, Rankins says. The hardware has proved so reliable, he adds, new RNB products will feature almost double the number of PEM fasteners: 256 in each unit.


Problem-solving software improves interface

Cambridge, MA--Developed in the former Soviet Union, Invention Machine Corp.'s IM Lab demonstrates that the thawing of the Cold War permits technology to flow both ways. The engineering support tool revolves around a vast database of engineering and scientific principles, each illustrated with diagrams, with an expert-system-like search engine.

While IM Lab contains volumes of information most engineers have never encountered, the Soviet-style interface required patience. The TechOptimizer module is Invention Machine's solution to the database sausage line. With it, engineers input a description of their problem as parameters using block diagrams and a Windows 95/NT interface.

TechOptimizer guides the user to construct a problem as a system of components, functions, and useful and harmful actions. This process in itself may suggest a solution. If not, TechOptimizer processes the input for querying any of IM Lab's so-called problem-solving modules: IM-Principles, IM-Effects, and IM-Prediction. A search may return a number of solutions based on physics, chemistry, thermodynamics, electromagnetic theory, or other laws of nature. Ideally, the engineer now has a better understanding of how to design a solution.


Code hopping foils car thieves

Auburn Hills, MI--Two of the Big Three U.S. automakers hope to take a bite out of crime by implementing Siemens Automotive's advanced vehicle immobilization system technology beginning with 1998 model year vehicles.

The system completely immobilizes a vehicle's engine if someone doesn't insert the correct electronically coded key in the ignition. It works by using a "rolling code." Each time the engine is turned off, the system instantly rolls to a new code that only the ignition key reads and remembers until the next time the driver starts the engine.

Another key to the system design is use of inductive energy to transmit the correct code throughout the system. High-tech scanning devices--common among car thieves--cannot read inductive code. Savvy car thieves have been using sophisticated scanners to decipher the codes of many of the electronically activated antitheft systems now in use.

Since its introduction in Europe in 1995, German insurance companies have attributed declining car-theft rates to this technology. In one year, 13,000 fewer vehicles were reported stolen--a 9% drop. In fact, German insurance companies specified in 1995 that car buyers purchasing new vehicles not equipped with Siemens' or a similar antitheft system be penalized by as much as 10% of the vehicle's replacement cost if their vehicles are stolen.


Stator encapsulation boosts productivity, reliability

Rockford, IL--Pacific Scientific engineers have developed an innovative new way to make stators for stepper motors that increases manufacturing productivity, while improving motor reliability. The trick: encapsulating the stators with a thermoplastic polyester resin, and performing the feat in a single injection-molding step.

By replacing time-consuming epoxy potting and other assembly operations, the encapsulation with 30% glass-fiber-reinforced Rynite(R) PET (polyethylene terephthalate), supplied by DuPont Engineering Polymers, Wilmington, DE, takes care of three key stator functions:

- Protecting the stator windings against vibration as well as from contamination by foreign matter.

- Forming an integral end bell with integral provisions for the way encoders are mounted.

- Enclosing lead connections in a rugged, long-lasting housing.

However, the benefits don't end there. "Changing from epoxy to Rynite gave us a dramatic reduction in cycle time," says Brad Trago, an engineering manager at the Pacific Scientific Motor and Controls Div. Potting with epoxy took two hours, including two curing cycles in ovens. Encapsulation with the PET takes just 45 seconds, according to Trago.

The change of encapsulation method also eliminated the need for 11 parts, including a printed circuit board, and simplified assembly. Winding leads are now welded to an eight-pin connector strip, instead of attached to the circuit board with eight insulation-displacement connectors soldered in place. Slot liners of Rynite PET, also used with the epoxy-potted stator, were modified to eliminate connector recesses.

In addition, thanks to the insulating effect of the encapsulation, the end bell, where the encoder mounts, runs more than 30C cooler than the aluminum bell formerly used. As a result, customers can specify lower-temperature, lower-cost encoders. Molded-in holes provide for press-fitting inserts to retain the encoders. This, in turn, provides greater flexibility in encoder mounting options.

"DuPont engineers helped us throughout the development process for the stator," Trago adds. "We came to them with a design concept, but with no experience in injection molding. DuPont's support was crucial in resolving problems during prototyping."

Pacific Scientific's Powermax II(R) motors are the most powerful NEMA 23 step motors available, Trago reports. They come in a full range of standard sizes and many custom configurations. Typical applications: factory automation equipment, packaging machinery, vending machines, and computer printers.


Decoder chip set spurs DVD-ROM drives

Irvine, CA--Toshiba has developed a DVD decoder chip set with a copy-protection processor that implements a scheme recently approved by the DVD Consortium to prevent "pirates" from illegally copying movies and other entertainment. Toshiba is also using the chips in its own DVD (digital video disk) players and DVD-ROM drives.

Hardware designers can use the chip set to implement core circuitry for a decoder board that would allow DVD-ready PCs connected to a DVD-ROM drive to play titles that use MPEG2 video compression. It supports all four DVD formats: single-sided, single-layer 4.7-Gbyte disks; single-sided, dual-layer 8.5-Gbyte disks; double-sided, single-layer 9.4-Gbyte disks; and the soon-to-debut double-sided, double-layer 17-Gbyte disks.

The chip set comprises:

- Copy-protection processor, which performs authentication and descrambles encrypted data from copy-protected materials.

- MPEG2 video decoder, which separates DVD program streams into video, audio, and sub-picture streams.

- Video processor, which performs sub-picture stream decoding and video mixing.

- NTSC encoder, which accepts decoded digital video and outputs it in NTSC digital format.

- AC-3 audio interface, which provides audio/video synchronization and audio stream buffering.

- Audio-output IC, which receives output from the AC-3 decoder and provides analog and digital audio output.

DVD-ROM drives and DVD players feature MPEG2 decoding of moving images with a resolution of 720x480 pixels and seamless replay of data dispersed throughout the disk. Interactive applications will include self-paced training/teaching programs, movies with multiple endings, and sports videos offering a choice of viewing angles and on-demand player profiles.

The DVD logic decoder chip set costs $75 each in 1,000-piece quantities. Toshiba also offers a reference design for a DVD-compliant decoder board with a PCI bus interface, and an OEM kit that includes software drivers.

Application Digest

Application Digest

Reducing cost with motion controller/PLC integration

By Garyh Hager, Acroloop Motion Control Systems, Inc., Chanhassen, MN

Traditionally, servo and stepper motion controllers are antiquated in their handling of digital I/O. Most motion controllers handle digital I/O with high level code, such as IF-THEN statements. However, IF-THEN logic programming is often awkward and time-consuming.

One alternative to this time-consuming technique is the use of an integrated PLC and motion controller. Using servo and stepper motion control boards that take advantage of the processing speed of a floating point digital signal processor, the on-board PLC is programmed using Boolean logic commands. The Boolean commands are then translated into machine code on the fly with the floating point DSP. This programming technique allows the PLC scan rate to be on the order of a dedicated PLC scan rate.

Because the motion controller/PLC uses a pre-emptive multi-tasker, several motion control programs and PLC programs can be operated simultaneously. The ladder logic diagram shown can be programmed into the PLC program spaces of the motion controller. A further advantage is that the on-board PLC can access built-in hardware flags through the motion controller. Thus the PLC controls not only the digital I/O, but also the motion control hardware flags.

Currently, the motion controller/PLC cannot replace all PLC operations. But it can be used in applications requiring both motion control and simple PLC logic control. If the application requirements allow the motion controller PLC to be used, a separate PLC no longer is required, resulting in material and labor cost savings.

To speak with an Acroloop Motion Control Systems engineer, call 612-474-4500.


Simpler, more accurate blood pressure measurement

Peter Hutchings, Pneutronics Div., Parker Hannifin Corp., Hollis, NH

In traditional automated, non-invasive blood pressure monitoring, a pump inflates the patient cuff to 250 mm of Hg. Two digital (on-off) solenoid valves are cycled to control the deflation of the patient cuff in steps of 8 mm of Hg. This approach, although adequate, results in relatively slow blood pressure determination and patient discomfort due to initial high cuff pressure.

An alternative technique substitutes a VSO-NC normally closed proportional valve for one of the digital valves. The NC proportional valve controls the deflation rate and eliminates the need for the 8 mm of Hg decompression step, as it can achieve any inflation or deflation rate. The remaining digital valve is used merely as a safety valve.

Yet another alternate circuit substitutes a VSO-NOTM normally open proportional valve for the NC proportional valve and the digital valve. The NO proportional valve controls the inflation or deflation rate, and since it is normally open, the need for the other digital valve is eliminated. As with the NC proportional valve circuit, it can accurately simulate almost any orifice size smaller than its maximum.

By employing this technology in non-invasive blood pressure monitoring, measurements are more accurate and patient comfort is improved.

To speak with a Pneutronics applications engineer, call 603-595-1500.

Technology Bulletin

Technology Bulletin

Sounding out improved materials

Mechanical engineers at the National Institute of Standards and Technology (NIST) have developed an inexpensive acoustic wave transducer that soon may make it easier for researchers to decide if new composite materials or film coatings have the proper mechanical properties for specific applications. The transducer sends a pulsed sound wave through a test sample that is submerged in water. The speed of the reflected wave provides a measure of the material's elasticity (its ability to flex under stress). The direction of the reflected wave provides details about crystal planes or defects within the material. Current acoustic microscopes use "lenses" and may cost hundreds of thousands of dollars. The NIST device uses off-the-shelf parts costing less than $20,000, yet can provide similar data about materials' properties, researchers claim. Instead of a lens, the NIST instrument uses a curved transducer made with an inexpensive piezoelectric plastic film. Electrical signals cause the film to emit relatively low-frequency, pulsed sound waves. The curvature of the film focuses the waves in the same way that curved mirrors in telescopes focus light from distant stars. The transducer is positioned above the sample and then scanned or rotated through different angles to get a full picture of the material's elastic properties. Phone Nelson Hsu at (301) 975-6630.


1997 economic outlook: partly sunny and mild

The U.S. economy remains fundamentally sound, and the current economic expansion that began in the spring of 1991 will continue through 1997. So reports Cahners Economics in the Cahners 1997 Economic Outlook, published by Cahners Publishing Company, a division of Reed Elsevier PLC. The report goes on to predict that overall GDP growth should reach 2.3% this year, with business investment and exports leading the way. Inflation, says Cahners Economics, will remain relatively benign, and long-term interest rates will stay low enough to encourage reasonable gains in consumer durable goods purchases and business capital spending. For a copy of the $50 report, phone (800) 662-7776.


Micromachined silicon to handle fluids

Lucas Novasensor , Fremont, CA, has received a multimillion dollar contract to develop advanced micromachining technologies for microfluidic systems. Funded by the Defense Advanced Research Program Agency (DARPA), the program's objective is to design MEMS (microelectricalmechanical systems) structures for microfluidic system integration. Researchers are employing Deep Reactive Ion Etching (DRIE)--the latest process technology--to achieve the small size required to downsize analysis equipment used in biochemical, biological, and genetic analysis systems. DRIE equipment will sculpt silicon into devices for handling critical fluids within analysis equipment. Fluid handling is critical in the analysis of pharmaceutical, biochemical, and biological liquids. For example, integrated microfluidic solutions are becoming necessary to meet cost and throughput requirements for genetic and DNA analysis systems. Researchers expect that microfluidic handling devices will help reduce equipment size and cost while improving the performance and efficiency of each system. Also involved in the research are Stanford University and Perkin Elmer's Applied Biosystems Group. FAX Lucas at (510) 770-0645.


Flash-memory density doubles

Double Density Flash--or D2--doubles the capacity of flash-memory storage products and significantly reduces flash prices. So claim SanDisk Corp. and Matsushita, who developed the technology. They achieved double density by integrating SanDisk's proprietary flash memory cell and design technology with Matsushita's 0.5-micron CMOS process technology. Flash capacity essentially doubles because the D2 flash enables the storage of two bits of data--instead of the usual one bit--in each flash cell while the chip size increases only by approximately 10% to accommodate the extra circuitry needed. The two firms also announced that they have developed a 64-Mbyte flash chip, which they say is the highest-density component produced with D2 technology. Sampling to OEM customers will begin this quarter. In the works is a 256-Mbyte flash chip. Flash memory is rewritable and retains data without power. It's used in PDAs, cellular base stations, automobiles, digital cameras, digital audio recorders, patient medical monitors, global positioning systems, and many other products. FAX SanDisk at (408) 542-0503.


Metal matrix composite enables lightweight vehicles

Boralyn H and E series of advanced metal matrix composites from Alyn Corp., Irvine, CA, are stiffer and lighter than aluminum and have a greater specific strength and stiffness than titanium, aluminum, or steel, say company officials. These properties make the series of aluminum boron carbide composites ideal for applications in aircraft, satellites, and surface and rail vehicles. Boralyn can be extruded, forged, investment cast, and Alyncast--using a proprietary casting process. The material can be welded to itself and other metals using a standard T.I.G. welder. Manufacturers can also subject the material to rolling, machining, heat treatments, and finishing with such standard techniques as plating, anodizing, and ball burnish. Automotive applications include brake disks, drums, and calipers; and turbine and internal-combustion engine components including cylinder sleeves, gears, drive shafts, rocker arms, pistons, connecting rods, valves, bearing supports, and turbine vanes. Aircraft components include frames, doors, handles, skid plates, and structural members for satellites and antennas. Visit http://www.alyn.com or FAX (714) 475-1525.


Lightweight 'body-in-white' to be made from steel

The UltraLight Steel Auto Body (ULSAB) Consortium has selected vendors to produce various sections of its demonstration bodies-in-white. A body-in-white is a car's architectural structure to which are attached other components such as closures, suspensions, engine and transmission, glass, and interior components. It includes subassemblies for front, underbody, side, and roof modules. The consortium comprises 33 of the world's leading steel companies, and is funding and promoting the project, which seeks to demonstrate the untapped potential of steel to contribute to lighter weight auto bodies that meet a range of safety and performance targets. Each vendor chosen is responsible for building tools and other necessary hardware and for producing and delivering finished parts and subassemblies. Plans call for fully assembled ULSAB demonstration bodies to debut early in 1998. For more information, FAX (810) 351-2691.


DARPA awards contract for battlefield LCDs

The Defense Advanced Research Projects Agency (DARPA) has awarded a $2.75 million contract to dpiX, a Xerox New Enterprise company, to develop high-resolution reflective-mode display technologies that could provide soldiers on land with digital maps, real-time video, and other strategic and tactical information. dpiX has already produced active-matrix liquid-crystal displays containing seven million pixels that provide image resolution of 300 dots per inch over an area the size of an 8.5x11-inch page--the equivalent of reading a paper document on a computer screen. "Team leaders are already carrying ruggedized laptop computers into the battlefield, but weight, glare, and low resolution limit their usefulness," says Carl Cobb, general manager for display products at dpiX. "The reflective LCD technologies we're developing under the DARPA contract could lead to a generation of wrist-mounted and handheld displays that will be much more readable outdoors and provide soldiers in the field with a wider variety of information." Technologies developed under the two-and-a-half year DARPA contract could also be used to create next-generation commercial portable devices. For details, visit http://www.xerox.com/dpix.


Secure contactless smartcards in the works

Motorola has developed a "contactless" smartcard microcontroller with security levels it says match those of contact-based smartcards. Contactless memory cards offer significant benefits in such areas as public transportation, but have to date been limited to applications with low security requirements. Motorola's announcement could pave the way for higher security electronic purse applications, such as those being piloted throughout the world by MasterCard and Mondex. These applications could now in theory be held on multifunction contactless smartcards. "Using a card based on the new chip, a commuter would be able to load his smartcard with money at an ATM or down a telephone line and use the same card as a contactless travel pass, giving huge savings in time and effort," says Mike Inglis, Motorola's worldwide smartcards operations manager. Transport authorities are currently investigating contactless ticketing systems in major cities throughout the world, including Barcelona, Spain; San Francisco; and Adelaide, Australia. In the United Kingdom, London Transport is evaluating systems based on the technology for its Underground rail and bus network. Visit http://design-net.com/csic.


BMW crash-tests virtual reality

BMW's R&D Center is using virtual reality to visualize and interact with crash-test data. At the BMW corporate R&D center in Munich, virtual reality technology is being assessed for various applications within the automotive design and engineering process. In previous years, car manufacturers were obliged to build and crash a large number physical models of any new vehicle. The introduction of electronic models and computational intensive analysis methods have proven to be of real benefit to both the automobile designer and crash test engineer. In cooperation with the University of Erlangen and Sense8 Corporation, a project is being carried out to develop VR techniques for advanced visualization of vehicle crash worthiness simulations. The idea is to allow the user to enter a virtual environment that contains geometry data of the vehicle plus the results from all stages of a simulated crash test from existing analysis methods. Based on both the current finite element analysis testing packages and WorldToolKit, the new environment allows the engineer to interact with virtual objects and analyze crash testing simulation results, thereby obtaining information not readily available in a real world testing situation. Ease of development and performance were considerations in selecting WorldToolKit for this project. For more information, e-mail Tim Johnson at timj@switz.com.

Aerospace picks up the pace

Aerospace picks up the pace

Despite consolidation, there is considerable growth on the horizon in the commercial airplane business--and that means more work for design engineers.

That's among the lessons from a special worldwide fact-finding tour completed by Ken Blakely, vice president and manager of The MacNeal-Schwendler Corp.'s aerospace business unit. Being the forward-looking company that it is, MSC believes in the importance of such fact-finding tours of companies in its key market areas. On this trip, Blakely visited 18 aerospace companies for the developer of engineering analysis software--four each in China and Korea, two each in Singapore, Japan, the United Kingdom, and Germany, and one each in Indonesia and France. His two conclusions: There's a flurry of activity in big projects, and there's a burgeoning indigenous market for regional airplanes.

Among his specific findings:

- China, Indonesia, and Korea are each building 100-seat jets.

- Additionally, there are some jumbo-jet projects on tap, such as the Airbus A3XX.

- These and other projects hold opportunities for multi-national companies. For example, IPTN, the Indonesian Aerospace Company, will go outside the country's boundaries for about 30% of the components it needs. Likewise, China will work with five European companies and Singapore Technologies Inc. to build its plane.

- U.S.-designed planes are increasingly being assembled in the Asia Pacific region.

- There's growing interest in Asia in technology pioneered by Boeing, McDonnell Douglas, and Airbus. "Everywhere I went, engineers asked me what these companies were doing and what engineering tools they are using," Blakely says.

He sees in this interest and activity many opportunities for U.S. companies. For example, those who design and build propulsion systems should prosper--the U.S. and Europe will continue to be the sources for that technology. Companies that supply landing-gear hydraulics will do well too, as will those that supply materials and fastening systems.

Closer to MSC's heart, there is also plenty of opportunity for those companies that can provide analysis solutions. "The companies I visited are moving toward simulation-based design--and they want to simulate all kinds of phenomena," he says.

"I'm excited about the flurry of activity I saw overseas," Blakely says. So too should be design engineers, whose talents, as always, are the keys to success.

Standards Update

Standards Update

ISO's sluggish pace, high costs prompt demands
for rapid reform

The Geneva-based Central Secretariat of the International Organization for Standardization (ISO) is under attack from many ISO members. Leading the charge is the American National Standards Institute (ANSI), the U.S. representative to ISO. Growth of world trade has swelled demand for global standards. However, ANSI President Sergio Mazza contends: "Increasingly, this demand is being fulfilled by international consortia because many believe that the ISO process is too slow and expensive." Among industries that have sidestepped ISO by setting up standards-forming consortia are chemicals, consumer electronics, information technology, and photography. "Without dramatic improvements," Mazza adds, "ISO faces the risk of losing more major business sectors." He says the Central Secretariat must do more with less, just as many ISO members have done under budget pressures. In response, the ISO Council has ordered an ad hoc group to come up with suggestions for speeding operations and cutting fees. The group is to make its first report this month.


Pentagon's MILSPECs keep fading in favor of industry standards

More than 4,000 U.S. military specifications (MILSPECs) and standards (MILSTDs) bit the dust in the past two-and-a-half years. Meanwhile, the Pentagon has adopted more than 7,500 non-government standards, comprising nearly a fifth of all the specifications and standards listed in the Defense Department Index. The effort to reduce MILSPECs and embrace industry standards began in June 1994. It is accelerating, according to Paul G. Kaminski, undersecretary of defense for acquisition and technology. Speaking to a meeting of standards experts in Arlington, VA, Kaminski said benefits of the reform are starting to appear. He cited savings on major programs, including the Joint Direct Attack Munition, the C-17, the SMART-T, "and on thousands of small purchases of items like T-shirts and socks." Today, a program manager must first obtain a waiver and justify why the use of a MILSPEC or MILSTD is necessary. Before, the program manager had to justify the use of anything other than an approved MILSPEC or MILSTD.


NIST drafts global guidelines for evaluating machine tools

The U.S. National Institute of Standards and Technology (NIST) is playing a key role in updating international standards for evaluating machine tools. In late 1955, NIST's Manufacturing Engineering Laboratory took over a job pre-viously assigned to a European standards organization. The NIST lab became the secretariat, or administrative headquarters, for ISO's subcommittee on test conditions for metal-cutting machine tools. Since then, the subcommittee has landed global approval of 11 new or revised standards and is circulating 10 draft documents for industry comment. Four of the pending ISO standards for evaluating machining centers incorporate a U.S. guideline developed by a committee of the American Society of Mechanical Engineers.


Certifications under ISO 9000 leap 34% in nine months

Organizations around the world continue to embrace ISO 9000, the international standards for quality management. At least 127,389 ISO 9000 certificates had been issued in 99 countries up to the end of 1995. That was up from 95,266 certificates in 89 nations at the end of the previous March. The figures come from the latest certification survey by Mobil Corporation's offices around the globe. The United Kingdom had 41.3% of the certifications by last count. The rest of Europe had 31.4%; Australia and New Zealand, 8.3%; North America, 8.0%; the Far East, 7.2%, and the rest of the world, 3.8%. Thirteen countries appeared in the survey for the first time. They are Afghanistan, Barbados, Curacao, Ecuador, Iran, Jamaica, Kenya, Lithuania, Macedonia, Nigeria, Uruguay, Vietnam, and Yemen. An analysis of three fourths of all valid certificates shows 66.0% were for ISO 9002, 33.1% for ISO 9001, and 0.9% for ISO 9003.


Techniques for ensuring quality taught via CD-ROM, booklet

With the spread of ISO 9000, awareness of modern methods of quality control has entered all aspects of production from design to sales. Quality Resources of New York City has come out with two products to help engineers keep abreast of two such QC methods: statistical process control (SPC) and failure mode and effect analysis (FMEA). SPC Workout is a CD-ROM multimedia package that guides you through interactive exercises. Engineers throughout a firm can use it to learn advanced SPC techniques, including how to pick the best chart to use, how to set up a chart, and how to conduct a process capability study. The other publication, The Basics of FMEA, is a pocket-sized how-to booklet about a process that is a required tool for the automotive industry's QS-9000 standard. FMEAs identify special causes of variation before they occur--preferably at the design stage. Quality Resources' phone number is 800-247-8519.

Designer's Corner

Designer's Corner

Compensating coupling

Achieving optimal relationship between torsional stiffness and damping is no easy task. That's why the ROBA(R)-ES elastomeric servo coupling is especially suited for highly dynamic critical drives.

Two hubs and a flexible ring make up the coupling. During assembly, the star-shaped ring presses into specially designed claws under slight pretension. Result: backlash-free torque transmission at relatively high speeds, despite radial, axial, or angular shaft misalignment.

Elastomeric rings of different shore hardness vary torque, rigidity, and damping behavior.

Robert Whipple, Mayr Corp., 4 North St., Waldwick, NJ 07463, 201-445-7210.


Steel shapes

While aluminum extrusions are quite common, design engineers might be surprised to learn that extrusions can also be produced in carbon and stainless steel. Such parts offer advantages regarding strength, durability, corrosion, and heat resistance.

By heating and lubricating with glass powder, a round steel billet can be forced through a forming die to produce a shaped bar. Full-length bars are useful for applications such as custom rails; slices can be used to produce automotive hinges, valve bodies, or forklift attachments.

Shapes to 10 inches in diameter are possible, while part weights range from 1 to 60 lbs/ft. Almost any grade of stainless or carbon steel can be extruded.

U.S. Profiles, Inc., Box 720252, Atlanta, GA 30358, 770-992-0398.


Treaded belt

Tire tread patterns on automotive belts won't make driving in the rain any easier. But as Goodyear has discovered, the designs help belts run longer and quieter.

Automotive belts generate heat as they drive the fan, power steering, and alternator. Also, the pulleys which guide the belts into forward and backward bends, compress and stretch the rubber polymers.

Helical-cogged ribs relieve these stresses, so the belt runs several degrees cooler. In addition, the design's angled grooves and a noise-abating rubber compound can reduce sound by 15 decibels when compared with conventional serpentine belts.

W.K. Scherer, The Goodyear Tire & Rubber Co., Akron, OH 44316-0001, 330-706-1054.