August 1997

		Cockroach Car Ties for First Place In University Research Symposium Cockroach Car - The sight of a cockroach flying through the air, driving a one-foot-long electric car is evidence that muscle impulses can control an electric vehicle. It also propelled Steven Bathiche to tie for first place in the undergraduate paper category at the University's 1997 Research Symposium in April. Shown here, Bathiche (right) and Professor Jeff Bloomquist (left) test the vehicle. Steven Bathiche (EE '97) is interested in developing an intelligent wheelchair that can be driven by the severely disabled - so he started by building a car for a cockroach. When Bathiche came up with the idea of testing the ability of muscle action to control the motion of a vehicle, he decided to use insect muscle, "because of their relative simplicity and evolutionary prowess." He approached Jeff Bloomquist, an associate professor of entomology and specialist in insect neurophysiology for help. They chose the American cockroach for its robustness and large size - and for its impulse to fly when its feet aren't touching the ground. Bathiche and Bloomquist tethered a cockroach to a boom extending from the front of a toy remote-controlled car. They attached a thin-wire recording electrode to the insect's thoracic flight muscles. When the cockroach moves its muscles in an attempt to fly, the electrode delivers an electrical signal to an amplifier and filter. The signal is fed to a Motorola 68HC11 EVBU microcontroller, which processes the signal and drives the motor of the car forward via an electronic speed control. "It worked the first time," Bathiche reported. "That was really cool." Bathiche said that his most difficult task was interfacing a live, noisy nonlinear time invariant signal to a linear time dependant controller. "I used some filter techniques and a comparator to make the signal as clean as it can be." He also introduced some lag into the system, so that the motor "would not dither on and off quickly, and make things jerky." Bathiche said that his electrical and computer engineering courses were very helpful to his projects, specifically, microprocessors, digital design, electronics, and control systems. "I used a lot of assembler programming, a little digital design, some electronic design for the amplifiers, and knowledge of signal characteristics, feedback loops, and system properties," he said.

The Bradley Department of Electrical and Computer Engineering
Virginia Tech