Engineering News 7343

Machine vision eyes new applications

Newton, MA--Once reserved for the programming elite, machine vision is maturing into a flexible, powerful automation tool for electronic, aerospace, medical, and automotive OEMs--just to name a few. Now, with RISC architectures, faster co-processors, and more user-friendly software, machine vision is expanding into new applications.

The technology's earliest use was inspecting products in advanced manufacturing applications such as semiconductor fabrication and electronics assembly. Although such applications remain a core of the industry, performance improvements are broadening machine vision's scope.

For example, at Cognex Corp., Natick, MA, engineers recently designed a PC-based machine-vision system that combines a user-friendly "point-and-click" Windows(TM) development interface with grey-scale processing software.

Checkpoint software digitizes and analyzes images in 256 shades of grey and works with custom ASICs to accommodate manufacturing-process changes such as lighting changes and variations in part appearance and position, say Cognex engineers. The top-of-the-line 800 model uses a Motorola 68040 CPU running at 40 MHz for fast image processing.

The Checkpoint system lets manufacturing engineers create and implement advanced applications without extensive programming expertise or in-depth knowledge of machine vision, says Bill Silver, vice president of Cognex R&D. Such applications aren't limited to inspection. Cognex customers now use machine vision to calibrate automotive speedometers, verify camera assemblies, align integrated circuits, and count pills in membrane packaging. In many cases, these tasks had to be performed by hand in the past: a tedious and error-prone job.

At Aquity Imaging, Inc., Nashua, NH, engineers are applying neural-network technology to machine vision. Their PC-based Mentorvision(TM) system uses neural networks to generate a filter that discriminates between aesthetically acceptable and unacceptable products. This "intelligent vision" brings machine vision into applications previously reserved for human judgment.

For instance, at Colgate Palmolive, Paris, engineers are using Mentorvision to inspect multiple labels on household cleaners--as well as adapt to changes in bottle size, label language, and position. The vision system's neural networks "learn" a product by viewing good and bad products on the line and receiving instructions as to which is which from the operator. After processing 10-20 good samples this way, operators can refine the inspection by accepting or rejecting any non-conforming bottle.

Previously, Palmolive didn't use machine vision for inspection because frequent changes in label language and bottle size would have required time-intensive re-programming and de-bugging. Mentorvision's "show and go" approach lets Palmolive change the line to add promotional labels or bottle sizes in less than half an hour, say Acuity engineers.

Machine vision is also coming to laboratory automation. To better handle hazardous fluids such as blood samples, Acuity engineers are designing a robot that uses machine vision for guidance and to identify clinical specimens. The "AutoPrep" removes samples from a rack and either sorts them or places them in a centrifuge. The research is sponsored by the National Institutes of Health, and is typical of new arenas for machine vision.

John Agapakis, vice president of R&D at Acuity, explains, "Machine vision is always integrated with manufacturing, but we see machine vision being more and more integrated with the production process, and therefore more beneficial." The AutoPrep and similar systems protect workers from infection or repetitive-stress injuries, and can keep them out of dangerous environments such as hazardous-waste disposal operations.

Higher yields. At Ismeca U.S.A., Inc., Carlsbad, CA, engineers have incorporated machine vision in an electrical test system to boost through-put rates for surface-mount devices. The G116 combines electric testing and machine-vision inspection. Using a rotary vacuum turret to move the devices, it inspects in 2D or 3D to monitor lead condition, coplanarity, and packaging. The system handles as many as 6,000 parts per hour and reduces the risk of component damage, say Ismeca engineers. "In years past, the rate might have been 1,500 or 2,500 parts per hour," explains Ismeca marketing mananger Tom Clerici. The system also reduces cost by combining several operations. Previously, SMD makers relied on slower human operators to transfer products from test to inspection fixtures, or inspected every second or third device to save time.

Some machine-vision manufacturers, such as Imaging Technology, Inc., Bedford, MA; Vision Modules, Inc., Campbell, CA; and DI/MAC Technologies, Orlando, FL; supply modular machine-vision components that allow the user to select individual image-analysis components and upgrade in increments. Active Imaging, Incline Village, NV, specializes in IP67-rated stainless-steel cameras for machine vision in harsh industrial installations.

With enhanced performance, inspection at assembly-line speeds, and flexibility, machine-vision technology is gaining acceptance in mainstream manufacturing applications, as well as creating new ones. For machine-vision designers, the challenge will be to keep pace with fast automated processes, and use inexpensive processors to keep prices down.

--Andrea Baker, Associate Editor

IC vendors offer Fast-Ethernet designs

Houston, TX--In a move to speed development of high-speed networking schemes for desktop computers, four leading chip makers--Texas Instruments, National Semiconductor, AT&T Microelectronics, and Broadcom Corp.--are offering free reference designs to help engineers develop systems for the three 100-Mbps LAN standards.

The designs show how to link TI's TNETE100 ThunderLAN(TM) 100-Mbps Ethernet controller chip to physical-layer devices from the other three companies. These devices include: National Semiconductor's DP83223/DP83840 TWISTER(TM) chip for 100Base-TX networks, AT&T's ATT2X01 transceiver chip for its Regatta(TM) 100VG-AnyLAN family, and Broadcom's BCM5000 10/100BASE-T4 Fast-PHY transceiver to 100Base-T4 networks.

"The day of homogeneous networks is gone," says Joe Valente, TI's Networking Business Unit manager. "All four companies want to ensure that OEMs have the technology to deliver a variety of 100-Mbps Ethernet products to the market quickly."

Simulation boosts helicopter design

Leovil, England--Engineers at Westland Helicopters Ltd. are using computer analysis of flight-test data to improve designs, develop performance specs, and produce flight-manual information. In addition, the company's Aerodynamics Performance Group (APG) creates helicopter flight simulations for test pilots, allowing them to develop effective emergency flying maneuvers--before trying them out on riskier, expensive test craft.

"It is truly an outstanding tool helping pilots generate effective flight techniques," says Grant Matthews, APG prinicpal engineer.

Westland's simulation system presents a high-resolution reproduction of a cockpit instrumentation panel, as well as control box and message window, and a real-world outside view while "flying."

"Using the display, the pilots can input parameters to test new maneuvers and see how the simulation reacts," Matthews explains. In one case, pilots simulated take-offs and landings on an off-shore oil rig if an engine failed.

After actual test flights, information captured by the aircraft's on-board tape system is converted into thousands of small data files and stored in a mainframe computer. Westland engineers then transfer selected files to their workstation network, and have the option of placing up to 12 separate traces on screen.

"Once the data is analyzed, we produce a data set that tells us the power required to fly a particular aircraft model at any given weight, air speed, and ambient condition," Matthews says.

A new network of powerful workstations has cut the time required to display graphics simulation data from 30 minutes to 30 seconds, the company says. The company is using a network of Sun Microsystems SPARCserver 2, SPARCstation IPX, SPARCstation IPs, SPARCstation ELCs, and SPARCstation 10s, as well as Evans & Sutherland graphics workstation and Digital VAX computer.

For the future, the company is working on an enhanced simulation program with more 3-D graphics. "We are developing a pilot model that will actually fly the Coupled Rotor-Fuselage Program through various maneuvers to determine how the rotor interacts with the fuselage," Matthews says.

IBM serves up affordable CAD

Sommers, NY--IBM is wooing engineers on a budget with a slew of new workstations ranging from $6,000 to $11,000. Among them: six models built around the PowerPC processor, a chip jointly developed with Apple Computer and Motorola.

"I think they're absolutely dynamite," says Tom Copeland, director of workstation research at International Data Corp., Framingham, MA. "They've really redefined performance at the low end of the workstation market."

While IBM has not been known for low-cost workstations before, Peter Lowber at Datapro, Lexington, MA, says Big Blue has changed its strategy. "Suddenly, they're the price leader for comparable performance at the low end," he notes. "They have very aggressive pricing." A key reason: PowerPC, which allows the company to take advantage of high volumes to lower costs.

The Model 42T, at $10,945, features 16M memory, 1.1G, and a 120-MHz processor for $10,945. Company officials rate the machine at 118.2 SPECint92 and 116.5 SPECfp92, measures of integer and floating-point performance. The workstation is designed with 3-D graphics. The lower end 43P with 133-MHz CPU, at $7,620, does not yet feature 3-D graphics acceleration; but boasts performance of 176.4 SPECint92 and 156.5 SPECfp92.

IBM also introduced a new server, the Model C20, offering 32M memory and 1G disk storage for $19,200.

Powder metal lowers pump-component costs

Dexter, MI--A powder metallurgy (P/M) process designed for a variety of alloys, mild steels, and tool steels is helping design engineers use P/M in new pump applications.

The F2(TM) powder metal process, developed at Krupp Engineering, gives engineers the option to design with low-alloy and car- bon steels in strucural components. "The process expands P/M beyond the traditional territory of tool steels," explains President Philip Krupp.

For example, at Vickers Aerospace Marine Defense Group, Jackson, MI, engineers are using the process to lower the cost of fuel-injector pumps for aircraft. By switching from wire EDM to the F2 process for fabricating vane pump rotors, engineers lowered the cost of the preform. Parts produced with the P/M process require only finish grinding of the slots and opposing faces, and the internal spline no longer requires finishing, say Vickers engineers.

Likewise, using the P/M process improved the design of clips used to attach the motor and pump housing of a centrifugal pump developed by Marley Pump Co., Lenexa, KS. Stamped clips proved not strong enough, and engineers ruled out cast or machined clips as too costly and time-consuming. The F2 process reduced overall design time, say Marley engineers. The clips have a hardness of R_c 15 and exceed load-test requirements.

At the Sorenson Research Division of Abbott Laboratories, Salt Lake City, UT, engineers replaced machined aluminum components with P/M parts made of 316L stainless steel in a nutrition pump. The switch improved part quality, says Chief Process Engineer John Kirk. "We got a part that had a better appearance and greater durability," he adds.

The difference between the F2 process and convention- al P/M occurs during the second half of manufacturing, say Krupp engineers. The process uses higher, variable temperatures and pressures during sintering to boost finished densities by as much as 20%, they say, for final densities of 98 to 100%.

Thermoelectric units cool cellular base stations

Dallas, TX--Cooling an enclosure not only prevents components from frying, but can also let you use commercial-grade components rather than military grade. The difference? Commercial-grade electronics operate at up to 70C; military electronics operate at up to 125C, but cost twice as much.

Motorola's Cellular Infrastructure Group is developing an extensive wireless personal communications system. The system will use bay stations as relay points to transmit signals from cellular phones and other devices. The stations will be housed in 2.5x2x1-ft enclosures located on building exteriors and telephone poles.

When Motorola wanted to have an enclosure cooled to 50C to use commercial electronics, the company turned to Marlow Industries, which developed a design that uses thermoelectric coolers in the enclosure doors.

A standard compressor system wouldn't work in the enclosure because of its size and the inability of the working fluid to recondense. Thermoelectric coolers are much smaller and inherently more reliable because they have no moving parts. They are essentially heat pumps made of bismuth telluride semiconductor material. Direct current moves heat from one side of the module to the other.

Inside the enclosure door, three groups of six thermoelectric coolers wired in series draw 9.4A at 156V. Each group is sandwiched between two heat exchangers. A squirrel cage fan moves air throughout the enclosure, stabilizing the temperature at 50C in ambient conditions.

"We had to specially design the coolers to fit this application," says Marlow Project Manager Lance Criscuolo. "The design offers ease of manufacturability for Motorola. For units that require active cooling, the thermoelectric door is attached. Units that will be located in cold climates will have a standard door. The units can be manufactured on one assembly line."

Cavity-alignment jig helps illuminate subatomic particles

Port Washington, NY--Since July, physicists at CEBAF, the $600 million superconducting continuous-electron-beam accelerator facility in Newport News, VA, have been studying the behavior of gluons and quarks within a nucleus. The research harnesses the nearly speed- of-light beam's particle nature.

CEBAF's 4-billion-volt electron beam gains its energy from five "laps" around the accelerator's 7/8th-mile-long "oval:" two electron "drag strips" containing 160 superconducting oscillating- electrical-field niobium cavities connected by two 180 degrees magnetic-force "turns." Each trip down a drag strip boosts the beam by 400 million volts to add 800 million volts per lap. Because the niobium cavities superconduct when they are cooled to -456 degrees F with liquid helium, they do not heat up when the accelerator is operating. This allows CEBAF to run continuously, which is unique among particle accelerators.

For CEBAF to accelerate its beam properly, the axes of each individual bowl-to-bowl shaped niobium cavity must be aligned to within 10 microns during assembly. To accomplish this, Danny Machie, a senior engineering associate at CEBAF, designed a cavity-pair assembly and alignment fixture that uses chrome-plated rails and pillow blocks from Thomson Industries, Inc.

C-clamps mounted on four of the fixture's Super Ball Bushing bearing pillow blocks hold the cavities in place, and the 1.5-in 60 Case Tubular Lite LinearRace Ways allow the cavities to be brought smoothly together along a single axis. By adjusting three plastic screws on each clamp and measuring from reference points on the rails, each fixture's eight cavities can be aligned in just three iterations. After alignment, the cavities can be transfered to either a test bench or the accelerator itself, where mounting flanges maintain the alignment and the fixture is removed.

Omron supports Design News Foundation again

Schaumburg, IL--Omron Electronics, Inc. has announced that it will once again support the annual Design News Engineering Awards program with a $10,000 gift to the Engineering Education Foundation. The gift marks Omron's fourth year of participation in the program benefiting engineering students at the university level.

"Omron is proud to again sponsor this powerful program to lift the awareness of the engineering arts and support the pursuits of dedicated students. By supporting the growth of young engineers, we know we are contributing to the overall growth and prosperity of the country and the world," comments Frank Newburn, executive vice president of Omron.

Omron employs more than 1,300 engineers worldwide who work in areas including material science, mechanical design, bioengineering, electronic design, and optical system design. "Our life-blood and our value to our customers depends on there being a continuous stream of talented young engineers," says Newburn.

Omron ranks as one of the world's leading suppliers of factory automation and control components including sensors, process controllers, vision systems, relays, PLCs, and optical switches.

In addition to the EEF donation, Omron continues to support the engineering arts in other ways. For example, the Omron Foundation, Omron's philanthropic arm, offers continued support to engineering students via ongoing scholarship programs with five universities in Illinois.

Omron also continues to direct its local product engineering staff toward the design and development of software and hardware products for the North and Central American markets. Within the last two years alone, Omron has nearly doubled its product development and application engineering staff.

The results of these investments include improved support services for Omron's engineering customers and new product solutions such as the new E3JU general purpose photoelectric sensor and new Analog Input module for their large rack PLCs.

'Smart' sketchpad captures drawings electronically

Cestas, France--An "intelligent" sketchpad with patented pressure-sensitive electronic pen enables designers to develop ideas from doodles to concepts--and then transfer them to a 3-D CAD system.

Using Lectra Systemes' Graphic Instinct, the designer sketches freehand directly onto a high-resolution (1,280 x 1,024) screen. The electronic pen can simulate a felt-tip marker, pencil, pen, or brush in a wide variety of colors.

As the sketch proceeds, a unit built into the top of the screen detects infrared and ultrasound signals emitted from the pen. This ensures that details of the drawing are captured electronically. So stored sketches can be subsequently modified without redrawing.

A system of triangulation determines the pen's position in space, as well as information concerning its rotation. This system is based on detecting ultrasonic signals transmitted from a number of sources within the pen. The receivers situate along the top of the screen.

By building a resistance sensor into the pen, Lectra Systemes differentiates between light and heavy pen strokes. The resistance sensor digitizes the pressure applied and sends the signals to the computer via ultrasound.

Once a design is finalized, it can be exported to a CAD workstation for further detailed design work. Intended for designers with no computer skills, the "intelligent" sketch pad is based entirely on visual icons.

Following demonstrations of the first prototype in Milan in March, the pad was installed at a number of test sites. First commercial products should be ready for delivery this summer, at prices ranging from 250,000 to 300,000 French francs (about $50,000 to $60,000 U.S.).

--Anna Kochan, European Editor, France

Sporty Sunfire won't empty your wallet

Watertown, MA--You've likely seen Pontiac's new Sunfire everywhere this summer: streaking down the Great Wall of China, doing donuts around the Leaning Tower of Pisa--and touring the Boston area with me behind the wheel. The $13,764 SE Coupe I drove for a week had the usual standard features, plus some you'd only expect to find in a more expensive car.

For example, in the Sunfire you'll be pleasantly surprised by rear-seat heating and ventilation ducts, battery-rundown protection, theater dimming of interior lights, a rear folding seat, front- and rear-seat cupholders, and an oil-level sensor. One feature Pontiac is especially proud of is the 4.9-l glove compartment, which can hold 12 cans of the beverage of your choice.

Controlled by a 5-speed manual transmission, the 133-cu-in, 2.2-l OHV four-cylinder engine delivers 120 hp at 5,200 rpm and 130 lb-ft of torque at 4,000 rpm. Pontiac estimates mileage at 24 mpg city and 35 mpg highway. A 2.3-l DOHC in-line four-cylinder engine is also available, as are three- and four-speed automatic transmissions.

Safety features include dual front-seat air bags, 4-wheel antilock brakes, side-guard door beams, and a slotted-frame rail design for increased occupant protection during frontal collisions. The front suspension has a stabilizer bar; the rear suspension features a coil-over-shock design. Having the shock and spring "in line" isolates passengers from bumps and bounces, resulting in a solid and controlled ride.

Although Senior Editor Sharon Machlis prefers the ride and interior of the Dodge/Plymouth Neon, I prefer the aesthetics and sportiness of the Sunfire. The suspension was good and stiff, shifting was easy, and I had a ball zooming around in this hot little number. I enjoyed the experience even more knowing that I could actually afford to buy the car.

--Julie Anne Schofield, Associate Editor

Electric roadster delivers low-cost, fun transportation

Palm Bay, FL--In June, Renaissance Cars Inc. (RCI) began shipping its first electric roadster, the Tropica. Weighing 2,160 lbs, the sporty-looking two-seater easily reaches 55- to 60-mph cruising speeds.

Two advanced-technology 24.5-hp DC motors provide the motive force, driving one rear wheel each via cogged belts. Twelve six-volt lead-acid batteries offer a range of 60 to 80 miles, and the company says that optional advanced batteries extend that figure to more than 100 miles.

Most important--as any Detroit engineer knows--is cost. "The goal was to demonstrate that it's feasible to build, from the ground up, an electric vehicle for under $20,000, battery pack and all," says Jack Guy, manager of electric-transportation commercialization at the Electric Power Research Institute (Palo Alto, CA). Production of the Tropicas beat that figure considerably, and they will grace RCI's initial 21 showrooms at an suggested retail price of $17,500.

--Mark A. Gottschalk, Western Technical Editor