Engineering Productivity Kit 2-16-98Engineering Productivity Kit 2-16-98

February 16, 1998

8 Min Read
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February 16, 1998

ENGINEERING PRODUCTIVITY KIT: ELECTRONICS

Sound power comes of age

by Laurie Peach, Associate Editor


Richmond, VA--Pistons, connecting rods, crank shafts, bearings and other mechanical moving parts may go the way of dinosaurs if Tim Lucas, president and CEO of MacroSonix Corporation has his way. "Resonant Macrosonic Synthesis (RMS) will replace complex machines that have been with us since the industrial revolution," Lucas says. During RMS, sound waves generated in gas produce energy densities thousands of times greater than ever before achieved in the field of acoustics.

Although the concept of using sound waves to transfer energy is not new, high-power commercial applications were limited because of acoustic saturation or the formation of shock waves. Once the inevitable shock wave is hit, additional energy is lost and higher dynamic pressures cannot be produced.

Lucas tackled this problem from the perspective of harmonic wave formation. He viewed the shock wave as the sum of other higher frequency waves, called harmonics. He discovered that for resonant sound waves, the cavity through which the sound waves travel is the most important factor in determining the shape of the wave. By manipulating the acoustic resonator geometry, Lucas generated sound waves capable of carrying high amounts of power without acoustic saturation.

After eight years of development, MacroSonix went public with the technology on December 1, 1997. "People told me to get a real job," says Lucas. "But I knew this would work. One day this was impossible. Today, it's possible."

Lucas claims that applications using RMS will be less expensive to manufacture and operate, be more efficient, and have increased reliability and durability as a result of few moving parts. "Look inside our technology and it is just a simple cavity filled with a gas," says Lucas.

"This works as advertised," notes Mark Hamilton, a professor of Mechanical Engineering at The University of Texas at Austin. "Whether industry will pick up on this remains to be seen. But it is a solution waiting for a problem."

The first commercial product to hit the market is an acoustic compressor "that eliminates the need for ozone-depleting chlorofluorocarbons (CFCs) and promises to be more energy efficient than standard compressors," says Lucas. To generate the sound wave, the entire cavity is oscillated and the motion transfers energy to the gas. The standing wave inside the resonator causes the pressure to oscillate high and low during one acoustic cycle, approximately 2 thousandths of a second. A discharge valve and a suction valve converts this pressure into gas compression and flow.

Suggested spin-off products include spot cooling for microprocessors, process control, process reactors for chemical and pharmaceutical industries, even power generation. The company receives 20 inquiries a day concerning possible applications. "We are just starting the technology development curve," notes Lucas. "Ours is a primary technology where new technologies will spring from for generations."


Piezos smooth snowboard ride

by Rick DeMeis, Associate Editor

Cambridge, MA--Far out, man--a snowboard that gives a smoother ride while allowing tighter, higher-speed turns, all while under control! The secret of K2 Corp's (Vashon Island, WA) new Electra snowboards is two vibration-eating piezoelectric dampers from Active Control eXperts (ACX). These are mounted near the left and right edges at the front of the board between the front boot binding and the nose--the area predicted to have the greatest vibrational displacement (strain).

The principle is the same as on K2's Smart Ski introduced two years ago (DN 2/5/96). Piezoceramic dampers convert mechanical vibration energy into electrical energy, which is applied across a shunt for dissipation as heat. An LED indicator lights when the board is vibrating so the rider knows the damper is operating.

ACX ran on-slope tests to determine the major snowboard vibration mode frequencies--the largest and most noticeable of which is the second mode. "The beauty of the technology is that it allows us to nail specific modes electronically, with no batteries required," says Adam Bogue, ACX vice president. "And the faster you go, the better it works." That is because the 80% vibration amplitude reduction gives more of a difference in absolute level with the greater amplitude vibrations that come as speed increases.

ACX says key to the snowboard system design was damper placement. Using finite element models with MSC/NASTRANTM from MacNeal-Schwendler (Los Angeles, CA), designers predicted induced strain across the board. These predictions were verified by strain-gage instrumented snowboard runs. Since strain produces vibrations, positioning the dampers in the highest strain areas has the greatest damping effect. The piezo dampers have a high mechanical stiffness, similar to the board materials, thus the dampers did not change the board characteristics and allowed efficient energy transfer to the damper. Cameron Andrus, senior design engineer at K2 comments, "Many professional riders say it's the best board they've ever used."


Rapid simulations take flight

Pensacola, FL--Raytheon E-Systems and Emultek Inc. (Herndon, VA) formed a strategic partnership to develop multimedia simulation training programs for the Department of Defense. Raytheon chose Emultek's Rapid SIMULATION4 software as the preferred software to create real-time, free-play simulations that can be seamlessly integrated with most major CBT authoring tools.

Emultek claims that Rapid PLUS is the only simulation tool that requires no coding. Using a simplified and powerful form of state-transition diagrams, non-programmers can link objects to create a fully interactive simulation by pointing and clicking. Users can build applications top-down, bottom-up, or any combination. Rapid PLUSreduces time-to-market for embedded systems by providing a suite of tools such as automatic specification, code and test script generation.

Rapid SIMULATION is a 32-bit, Windows-based, visual development environment that allows users to create fully functional simulations of interactive systems-- in a code-free environment.


New generation DSPs tout energy efficiency

by Debra Bulkeley,Contributing Editor

Houston, TX--If the efficiency of a 1-hp motor was improved by just one percent, the need for an entire 100-MW power plant would be eliminated. The technology that could enable this to happen: a digital signal processor (DSP).

Improving the efficiency and performance of motors are among the goals of a new line of DSPs that Texas Instruments recently announced.

Texas Instruments says that its four new DSPs will make electric motors more productive, quieter and energy efficient in applications ranging from home appliances to industrial automation systems. The devices are designed for digital control systems and power conversion and motion control systems, including inexpensive ac induction motors and dc brushless motors.

"One of the issues we looked at in designing the DSPs is how efficiently appliances run," explains Raj Chirayil, business manager for digital control systems, Texas Instruments. "Take a washing machine, for example. A lot of energy is wasted because we don't have an efficient way of running the motor."

Horizontal-axis washing ma-chines are becoming more popular, and the switched reluctance motors installed in them as well as in other appliances can be advanced-controlled with the new DSP. The benefits include smoother operation, reduced system vibration and improved energy efficiency. Chirayil adds that most systems using the new DSPs operate at a minimum of 98% efficiency.

The new devices, which are an addition to the company's currently available 24x DSP controller products, differentiate themselves from other DSPs on the market in that motor control functions are optimized and integrated on a single chip. Features include on-chip flash memory, control area networking (CAN), as well as a set of peripherals. One result: smaller devices that can be used to produce lighter, smaller motor drives or power supplies.

The DSPcontroller devices are based on Texas Instruments DSP cores and on-chip peripherals which, the company says, provides flexibility and improve system price/performance ratio.

Chirayil says samples of the F241 and F243 will be available during the second quarter of 1998 while the C241 and C242 samples are scheduled for third quarter availability. Volume pricing for 100,000 units is expected to range from $10 to $12 for the F241 and F243 flash units to about $7 for the C241 and less than $5 for the C242 ROM versions.


APPLICATION TIP

SMT transformers produce cost-effective ISDN devices

Mike McWilliams, Staff Engineer Pulse, San Diego, CA

The explosion of the Internet onto the worldwide scene, combined with the growth of corporate Intranets, telecommuting, and the small-office-home-office marketplace, has fueled an unprecedented demand for high-speed connectivity. To boost efficiency, many ISDN makers are converting their designs to 100% surface mount technology (SMT) components and processes.

Pulse engineers redesigned the new SMT transformer around an "open frame" construction that reduces the overall weight at the heart of the component. The new component's winding bobbins are formed from high-temperature plastic and internal solder connections using high-temp solder to resist any potential for component degradation from the 220 to 230C temperatures in today's SMT reflow ovens.

A key i

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