University of Rochester

Gravity Research Smooths Car Rides, Creates Jobs

February 22, 2000

Today's cars ride so smoothly that if you feel almost any vibration at all, you know something's amiss. That's because of extensive technology that automobile manufacturers use to cushion every pothole and road kill drivers are apt to encounter. Future rides should be even smoother, thanks to the contributions of Mark Bocko, an electrical engineer at the University of Rochester. Bocko has used his research on gravity waves to help the Buffalo company PCB Piezotronics create a new device that measures gradual motions like braking and cornering. As a result of the demand for the new device, PCB Piezotronics has added eight people to its workforce.

"Engineers have been calling us for years looking for this kind of sensor," says Jeff Dosch, technical director of PCB Piezotronics. "Now we can give them what they're looking for. This detector will help design smoother riding cars, safer aircraft and may someday enable a structure like a bridge to monitor itself for stresses due to aging and traffic vibration."

In designing a car, an industrial machine or a bridge, engineers need to know how vibrations and shocks affect performance. Besides being annoying, vibrations can cause fatigue in a car, making more frequent repairs necessary and cutting down the car's life expectancy. Designers can also determine how to make a car more likely to survive an accident by measuring the stresses it experiences in test crashes.

"My previous research was aimed at detecting gravity waves---the tiny ripples that spread out from a moving star," explains Bocko, a professor in the Department of Electrical and Computer Engineering. "We built detectors that could measure movement as little as one thousandth of the diameter of a proton. I contributed my experience in taking very sensitive measurements to help PCB develop their new line of extremely sensitive motion sensors."

The device that Bocko collaborated with PCB to develop extends the capabilities of the company's traditional detectors, which are based on a type of crystal called piezoelectrics that develop an electric charge when compressed. The one shortcoming of these devices is that they have trouble detecting slowly changing forces because the electric charge produced by the crystals gradually dissipates. The new sensor relies on "capacitive technology" involving tiny metal plates that change electrical characteristics depending on the distance that separates them. When a car with this sensor takes a tight corner, a weight pushes one plate closer to the other so engineers can gauge how much stress is being placed on the device all the way through the turn. If the force measured is unacceptable, the engineers can redesign the car to ride more smoothly.

"My interaction with PCB has been very enlightening," says Bocko. "The PCB engineers introduced me to a world of practical issues that I never had to consider while working on my gravity research. I have really enjoyed taking a more down-to-earth view on the technology that I've been involved in for so long. It's extremely gratifying to be able to contribute to the development of a new commercial product."