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Articles from 2001 In July


Teachers bring engineering into the classroom

Teachers bring engineering into the classroom

Austin, TX-Despite growing demand for technical skills, the number of college students earning engineering degrees in this country has dropped by 15% since the mid-1980s. But that trend may soon reverse itself, thanks to the efforts of teachers like Kathleen Crowe who are committed to bringing technology into the classroom.

Instead of spending her summer working on a suntan, Crowe-a fifth-grade teacher at Jack C. Murchison Elementary School (Pflugerville, TX)--just completed an eight-day, technology training session at the UT-Austin College of Engineering. This year, some 40 teachers of grades K-12 will participate in the workshop, which is taught by UTA engineering faculty and funded by National Instruments (Austin, TX). www.ni.com

During the two-week course, teachers learn how to build and program robots using LEGO building blocks, sensors and components, and software. These technologies make up ROBOLAB, a robotics set specially designed for students by National Instruments, LEGO Dacta, and Tufts University. www.ceeo.tufts.edu/graphics/robolab.html


The Composter shown here is one of the ten environment-friendly robots built by fifth-grade students in Kathleen Crowe's classroom at Jack C. Murchison Elementary School in Pflugerville, TX.

What teachers learn here will ultimately help shape their class curriculum, aided by more than 100 National Instruments engineers who will volunteer their time in the classroom. "Everything I learn here totally impacts how I teach," says Crowe, who initially learned about the program through a flyer in her mailbox. "I was so excited about the opportunity to expose my kids to robotics, and of course the fact that it offered free materials for teachers was a plus."

Crowe, who has participated in previous workshops at UTA, first introduced robotics into her classroom two years ago. This year's class built ten robots as part of an entire curriculum she developed on the environment. Students first researched a specific environmental issue, then designed a robotic device to solve a related problem, programmed it to carry out dedicated tasks, and created a web page describing their invention. www1.webramp.net/crowesclassroom/roboticshomepage.htm

The crew of eco-friendly robots includes the Super Trash Can, which uses a light sensor to detect when trash is thrown into the can and sounds an alarm to remind the person to use a recycling bin instead. Similarly, the H2O Saver uses sensors to collect and distribute rainwater.

"What they've done here isn't fluff," says Crowe. "My students aren't just learning about robotics, but getting a better understanding of how to apply technology to solve real-world problems."

That sounds exactly like what real engineers do every day.

Software helps assemble control systems

Software helps assemble control systems

If you've ever seen a robot maneuver into position and retrieve a bomb, then you're on track for understanding the importance of Sandia National Lab's modular architecture for robotics and teleoperation (SMART). "Smart is a software tool for assembling control systems in a modular fashion," says Phil Bennett, the project leader at Sandia responsible for SMART.

Bennett is working with a robot from REMOTEC (Oak Ridge, TN) and creating a wheeled police unit that makes how-to decisions on it's own, freeing it's operator to make critical "what to do next" decisions during dangerous bomb disablement operations. The robot makes repetitive decisions, like how to move through doors or down hallways.

SMART's applications include situations where quick control configuration is required for a movement that is performed once or performed differently every time, such as clean-up of hazardous materials or the removal of debris in an emergency situation.

For more information, visit Sandia's Intelligent Systems and Robotics Center at www.sandia.gov/isrc. For licensing inquiries, contact Sandia's Business Manager Ray Shaum at [email protected].

Eagle's nest rededicated

Eagle's nest rededicated

Auburn, MA--"The Eagle has landed," was radioed back to Earth 32 years ago this month as the first manned landing on the Moon was completed. But this event may never have happened if not for the first flight of a liquid-fuel rocket on March 16, 1926. Inventor Robert Goddard conducted the test on his "Aunt Effie's" farm in Auburn, MA.


The site of the first liquid-fuel rocket launch conducted by Robert Goddard, in Auburn, MA, was rededicated last Saturday by the American Institute of Aeronautics and Astronautics. Photo above shows Goddard and his first rocket. The site today below is marked by an obelisk and sits on a town golf course.

To commemorate the 75th anniversary of the launch, last Saturday the American Institute of Aeronautics and Astronautics rededicated the location as one of several significant aerospace sites worldwide.

The state fire marshal eventually halted Goddard's testing in Auburn, but the publicity surrounding the cessation attracted the attention of Charles Lindbergh and the Guggenheims who funded the work from then on. Goddard moved his testing to Roswell, NM and developed gyroscopic controls for his later rockets as well.

The family sold the Auburn farm after Goddard left to a golf course developer. It is now owned by the town of Auburn and is preserved as open space. The obelisk is alongside the ninth fairway and one of the original stone walls of the farm runs along there as well.

To find out more on Robert Goddard visit: www.gsfc.nasa.gov/75th/75th.htm.

New cat on the block

New cat on the block

Atlanta-Jaguar debuted its small sedan, the X-Type, to the automotive press last week. With a base price of $29,950 for the 2.5-liter 6-cylinder model, the company is aiming to bring a car with Jaguar handling and amenities to the entry-level small-luxury class now populated by the BMW 3 Series, the Mercedes C Class, the Audi A4, and Volvo S60. Jaguar says this is the fastest growing market segment.

Top features include full-time all-wheel drive (AWD), an optional five-speed manual transmission, and a 3.0-liter-powered version.


Jaguar's new X-type was run through its paces last week by auto journalists at the Atlanta Motor Speedway, and through the hills of northern Georgia.

After taking the car through road and handling courses at the Atlanta Motor Speedway, as well as into the hills north of Atlanta, I'd say it seems the design engineers have hit their mark. The car hugs curves tightly, but with a Jaguar "floating" feel. The AWD is transparent to the driver, with the majority of noise only coming from the tires and not the mechanical systems. Keep an eye on future issues of Design News for a full drive report.

The X-Type goes on sale officially August 1. To find out more, log on to: www.x-type.com

Chipping away aircraft ice problems

Chipping away aircraft ice problems

Researchers at the University of Illinois (UI) are taking a closer look at the flight dynamics of an iced aircraft. "The problem is how the ice changes the shape of the wings and other surfaces, which alters the aerodynamics," says Michael Bragg, head of aeronautical and astronautical engineering at the UI.

Knowing how an iced aircraft flies helps pilots make better decisions and ultimately fly the plane more safely when it has ice build-up.

"Our approach is providing the pilot with a near real-time characterization of the effect that ice is having on his aircraft," says Bragg. He explains that a pilot could mistakenly assume there is no problem and continue flying the aircraft as though it did not have ice. Also, the pilot may not initiate ice protection measures. The possible result: a dangerously unstable aircraft.

A flight test conducted this year is being used to validate the researchers' models and algorithms, A prototype of their ice management system will be tested next year. For more information, contact Bragg at [email protected], call (217) 333-2651, or fax (217) 244-5551.

Unigraphics Master Series?

Unigraphics Master Series?

At UGS' fourth annual Analyst/Press Event (July 16-18, 2001) officers of both UGS and parent company EDS spoke as much as regulatory agencies would allow about what may result from the merger of the UGS and SDRC product lines.

The acquisition of SDRC raises the number of UGS CAD customers from 18,000 to 24,000, and the number of seats from a little more than 1 to 1.6 million. But what will be on the desktops those seats represent?

UGS promises to protect the investments already made in both groups of products-with the proviso that some changes will be made. The first changes, not unexpectedly, will base future versions of I-DEAS on the Parasolid modeling kernel, and blend the analysis capabilities of I-DEAS into Unigraphics. Both I-DEAS and Unigraphics will be continued for the time being, but will probably become a single system in the future. While no future product names have been finalized, several presentations referred to "Unigraphics Master Series."

Seat gains on the PDM side of the business are more dramatic. UGS currently has about 18,000 seats of i-Man deployed, while Metaphase accounts for some 450,000 seats-the largest customer base in the field. Although event speakers said nothing specific, UGS seems to be positioning the two systems to be complementary-with i-Man continuing to be developed for the wor-group level of PDM, Accelis employed to transfer data back and forth between i-Man and Metaphase, and Metaphase itself positioned increasingly as an enterprise data system (EDM).

To paraphrase CEO Tony Affuso's presentation, the company plans to increase R&D spending dramatically, aiming for leadership in "repeatable digital design and design validation," and providing the "backbone for collaborative Internet and extranet collaborative commerce"-in other words, the $7.4 billion PLM market.

Fine tune your engineering knowledge

Fine tune your engineering knowledge

Do trade shows or plant visits sometimes leave you more harried than informed? If so, you may want to attend one of the many OEM supplier sponsored events tailored to your specific engineering discipline.

For example, some weeks ago DesignNews attended Phoenix Contact's Industrial Forum 2001. Typical of such well-run gatherings, the presentations, product displays, workshops, and discussions did not just focus on Phoenix Contact, but customers, partners, and systems integrators also participated.

The Phoenix Contact forum is an intense two days, running about eight concurrent sessions for six hours, plus a moderated panel discussion forum each evening. Even lunch can be informative. Talk at my table included the state of the design engineering profession vis-a-vis other professions.

In the formal sessions, topics ranged from efficient enclosure design to power supply heat. Here's a brief rundown of some noteworthy presentations:

Rittal Corp.'s (www.rittal-corp.com) Paul McGarry outlined emerging low-voltage power distribution methods and considerations that look to save design time, cabinet space, and provide more efficient industrial motor control and power feeds.

Tom Rosenburg from Balluff (www. balluff.com) described the company's inductive technology to connect moving assemblies with power and signals over short distances, thus avoiding the life and speed limits of sliprings, flex cables, and other physical contactors.

Phoenix Contact's Arnold Offner lead the host contingent with presentations including: a seminar on evolution and trends in design and packaging, a discussion on the thermal considerations of low-voltage power supplies and efficiency benefits of the latest developments; and a talk about 20 hints for optimizing installation of PLC systems.

Interested in seeing what other subjects were covered? For those, and information on Phoenix Contact's next event, slated for September in Charlotte, NC, go to www.phoenixcon.com.

Product News

Product News

Encoder

The HOG 16 hollow-shaft incremental encoder uses double scanning of incremental disk by two separate electronic systems mechanically displaced by 180 degrees . HTL-signals are electrically isolated and available for the control of two frequency converters or as a double safety system. The device is mounted on two 2,600-kW tandem drives on board a suction dredger.

Hubner Elektromaschinen AG
www.hubner-berlin.de
Enter 588

Delay line

A five-tap, solid-state delay line for 3V applications supplies total delays from 20 to 300 ns and tap-to-tap delays from 4 to 60 ns. The element comes in 8-pin DIPs and surface mount packages to save on pcb area. It is designed to reproduce both leading and trailing edges with equal precision. Each tap is capable of driving up to ten 74LS loads. Delays are specified over both commercial and industrial temperature ranges.

Dallas Semiconductor
www.dalsemi.com
Enter 589

Battery servicing

The CASP/2500 services emergency battery packs, often used to power emergency lighting on aircraft feature several automatic functions such as charging, discharging, capacity verification, and recharging. The system can recognize most common types of batteries and can be programmed to receive those types of batteries it cannot readily identify. The CASP/2500 can also assist when commissioning new battery packs placed into service for the first time.

Marathon Power Technologies
www.mptc.com
Enter 590

Digital signal controller

The 16-bit dsPIC digital signal controller combines the control advantages of a microcontroller with the high computation speed of a digital signal processor (DSP) to produce a single-chip solution for embedded systems designs. It provides DSP functionality in the familiar PICmicro microcontroller Integrated Design Environment, simplifying implementation by engineers familiar with microcontrollers.

Microchip Technology Inc.
www.microchip.com
Enter 591

Sensor technology's changing skyline

Sensor technology's changing skyline

Optimized triple coils extend sensor range

In the Q80 embeddable proximity sensor, Turck has taken its patented Uprox(R) technology and, according to Robb Black, sensor division director, optimized the system's two sensing coils to extend the range of detection of all metals out to 50 mm (up from 40 mm for previous embeddable sensors) for automotive, materials handling, and conveyor applications. A third (oscillator) coil in the sensor induces an eddy current in the target, which then produces a vector difference between the equal voltages in twin air-core detecting coils (see diagram). Because sensing only depends on the vector difference in voltages, there is no temperature limit on the sensor beyond that of sensor materials, he adds.


When no target is present to the Uprox sensor, voltages E1 and E2 are not equal or in phase. Oscillator current is thus low and the device is at a non-resonant frequency of 680 kHz. As a target approaches, mutual inductance from eddy currents in the target's metal surface shifts the frequency up to 700 kHz and E1 + E2 = 0, allowing current to flow, giving a sensor output. The target passes by the sensor, but E1 and E2 remain equal and 180 degrees out of phase with each other, vectorally adding to zero. By using this vector-differences method, the sensing range is independent of the material present.

Unlike conventional proximity sensors with a single oscillator coil, there is no ferrite core within the coil to obtain the needed high resonant quality factor (Q). Instead Turck designers use three precisely wound (tailoring the number of turns and wire size) and positioned coils. Without a ferrite core, Black says the sensors do not become saturated in high magnetic fields, such as near welding equipment on automotive production lines. And without having to oscillate a magnetic field in a ferrite core, sensor speed is "up to ten times that of a standard sensor," Black adds.

In addition to the long range, Black notes engineers were able to economize with a one-piece plastic potted housing. The sensor can be embedded within a floor or side structure of a machine, shielding it from damage-causing impacts. Options include the company's eurofast(R) quick connector for standard 12-mm connections.

For more information, Turck, www.turck.com; or Enter 549

DeviceNet comes to wide-ranging ultrasonic sensors

Hyde Park Electronics designers now have DeviceNet communications capability in their Ultrasonic SUPERPROX(R) SM956 30 mm Sensor Series. Mark Wagner, manufacturing test engineer, says surface mount technology electronics and new, smaller microprocessors were vital in putting this functionality into a compact package.


The Hyde Park Electronics DeviceNet capable SM956 30-mm diameter sensors come in stainless steel (left) or plastic housings and meet NEMA 4X and IP67 standards. Epoxy encapsulation resists shock, vibration, and harsh conditions.

DeviceNet decreases downtime, with fast, device-level diagnostics, and reduces installation cost. The 30-mm diameter units are 60% smaller than other sensors with the same functionality and are aimed at applications in loop control, monitoring material levels in bins and bowls, and controlling distance. The sensors can range out to do detection at 1 or 2m. The 1-m model, Wagner adds, "has a short deadband that allows measuring to inside of 2 inches." Dual-crystal technology, with separate transmitter and receiver crystals, is responsible for this close-range capability, he notes, because the receiver does not have to damp down before it is able to detect a return signal.

Unlike light-based sensing, ultrasonic sensors are minimally affected by dirt and dust, splashing fluids, caustic solutions, humidity, and high-pressure wash downs.

For more information, Hyde Park Electronics, www.hpsensors.com; or Enter 550

'High beam' light barrier

Severe levels of contamination, such as dust found in the lumber industry, make position sensing with light barriers difficult, if not impossible. The EA250/SA250 series of light receivers and transmitters from Wenglor Sensors operate with a high-intensity infrared light beam so strong it can peer through ten sheets of standard white paper. For ease of mounting and to keep the size of the receiver and transmitter units as small as possible, they are linked to a common control unit.

The LV250 Control Unit controls up to three receiver and transmitter pairs. But using the control unit's cascade facility, nine control units can be operated together to give a light barrier system consisting of up to 27 receiver/transmitter pairs. One control unit is designated as the master that monitors the other units as slaves. Jurgen Sprenger of Wenglor's electronics development section points out, "We've tried to simplify the setup as far as possible. Cascading does not involve any addressing and there are no miniature dual in-line switches that need to be set." A single strip connector interconnects the nine control units.

An automatic teach-in feature, furthermore, proves useful in applications where the sensor configuration changes frequently. Because each light-barrier pair has its own output on the control unit, switching status of the individual barriers can be interrogated. A group output, reflecting the logical state of the sensors connected to the control unit, supplies a signal monitoring all of the light barriers simultaneously. A simple selector switch in conjunction with a row of LEDs on top of the control is used for setup, mode selection, and indication.

For more information, www.wenglor-sensors.com ; or Enter 551

Collimated LED gives laserlike position sensor performance

With a starting price of $279, the Banner Engineering L-GAGETM Q50 Light-Gauging Analog Output Sensor gives laser position-sensor performance at one-third or less cost than that of a laser-based sensor, according to Technical Marketing Manager Mike Dean. He notes the key to achieving this precision is the exacting spherical lens bonded to the LED light source, resulting in a highly collimated beam of infrared or visible light, depending on the LED used. Another lens focuses this beam into a 1.5-cm (0.6-inch) diameter spot for use in tight spaces or on small targets. An image of the spot on the target passes through another lens into a detector to determine target position (see figure).


A precise, spherical lens bonded to an LED emitter produces a highly collimated beam in Banner Engineering's Q50 triangulation sensor. Image of hte resulting spot on a diffuse-surface target passes through a focusing lens onto an analog photodiode receiving element. The ration of output current from each end of the detector (I1/I2) provides target position determination.

The Q50's microprocessor eliminates the need for a separate controller, easing set-up time using a built-in teach mode. With a visible red LED, sensing range is 4 to 12 inches and with an infrared emitter range is 4 to 16 inches because of the detector's greater sensitivity at this wavelength. The user can select an output response speed of 4 or 64 msec. The sensor is designed for use in applications including dry-bulk level measurement, package filling, and loop control.

Dean adds that, as with a laser sensor, highly mirrorlike targets that would reflect the light spot in only one direction, are not suitable for detection with the sensor. While ultrasonic sensors could be used for position detection, the target must be very nearly perpendicular and in a "benign" environment.

For more information, Banner Engineering, www.bannerengineering.com; or Enter 552

Laser sensor reliably reads invisible markings

The SMARTEYE(R)STEALTH sensor from Tri-Tronics permits positive detection of invisible markings. Because it is red laser-based, the near infrared fluorescence induced in a specially formulated ClirCode(R) marking material from Isotag Technologies occurs in a portion of the electromagnetic spectrum away from natural fluorescence wavelengths activated by ultraviolet (UV) light-mitigating false readings. And unlike UV lamps, the laser-diode light source is immune to failure due to vibration. Sensor response time is 200 microseconds with leading edge variation less than 40 microseconds.

Dennis Henderson, vice president and sales manager, notes the sensor is aimed at security applications and those manufacturers who do not want registration marks or codes visible on their products. The chemical technology for the ink was developed by Los Alamos National Laboratory and the oil industry for security marking uses, Henderson notes.

The ClirCode can be formulated into water- or solvent-based materials such as inks, plastics, or adhesives and applied directly on materials. Any background is suitable, Henderson says, "except dark blue and black which absorb the red light." The sensor comes in three models: a long range (up to 8 inches) device for detecting large objects and marks; a convergent one with maximum sensitivity at 3 inches for small marking detection; and a model with a fiber optic light guide for sensing when a site is spacewise difficult to access or has a harsh temperature, vibration, or corrosion environment.

For more information, Tri-Tronics, www.ttco.com; or Enter 553

Accurate angle measurement at low cost

Sensors based on optical principles are often used to measure the angle of rotation on shafts. But such sensors are too expensive and bulky for many applications. One alternative, now offered by Novotechnik Stiftung & Co., is a non-contact Hall-effect angle sensor. Developed in conjunction with the Technical University (ETH) at Lausanne, Switzerland, the VX22 angle sensor consists of a cross-shaped piece of silicon in which each of the two limbs (x and y) form a vertical Hall sensor.


Like a normal Hall sensor, a voltage is produced across a current-carrying conductor when subjected to a magnetic field. The conductor, though, is split and folded back on itself with the electrodes on one side. In this configuration, the magnetic field flows parallel to the limbs of the cross in the x-y plane producing, as the angle varies, a voltage proportional to the sine of the rotated angle on one limb, and a voltage proportional to the cosine on the other limb. The two voltages are digitized and evaluated using a microprocessor, giving a 12-bit resolution. Depending on the application, the output may be digital or analog.

Josef Albano, product manager for the VX22, quotes an accuracy on the measured position of 0.35 degrees. He also adds, "Hysteresis on the angle measurement comes in at a barely measurable 0.045 degrees." Since the only part subject to wear is the ball bearing for the shaft, he expects a sensor service life of at least 100,000 hours. In principle, any of the commonly used interfaces can be realized digitally and a CAN bus interface is planned. Due to the low friction drive, a typical application for the new sensor is on remotely indicating wind-vanes.

For more information, Novotechnik Stiftung, www.novotechnik.com; or Enter 554

Microprocessor gives turbine meter flexibility

Microprocessor gives turbine meter flexibility

OMEGA Engineering's (Stamford, CT) recently introduced FTB790 Series turbine meters feature microprocessor-based electronics in a ruggedized, compact package for precision fluid measurement. The large, six-digit LCD display provides total flow and flow rate indication in a two-point floating decimal format for totals ranging from 0.01 to 999,999.

Flow Engineering Manager Hilda Burke notes the FTB790 is aimed at "Customers who say they are looking for a unit that will have rate and total that they can just walk right up to and read. Then if someone has a future application where there is a need to record values, they can get an accessory with an analog output for a recorder." Burke highlights the meter's flexibility, thanks to the microprocessor technology which was key to doing rate and totalization on a local flowmeter and allowing the optional output. She says such flowmeters are targeted for applications such as chemical processing, material batch processing, and water utility uses including wastewater management.

A user accesses all functions on the turbine meter via simple two-button operation. Twin lithium batteries power the device and its display, providing upwards of 4,000 hours of operation. The meter also features percent reading accuracy, signal output capability, the ability to read gallons or liters per minute (which must be ordered separately), and is FM approved. The device can be reset, or a user can lockout the reset function. Basic unit price is $486.

Additional Details...OMEGA Engineering, (203) 359-1660; www.omega.com, or Enter 508.