Model-Based Torque Control of Piezoelectric Ultrasonic Motors

Piezoelectric ultrasonic motors (PUMs) are ideal actuators for a variety of spaced-based robotics applications. These motors replace conventional drive systems consisting of motor, gear train, and brake with a rugged and reliable actuator containing one moving part. It is not currently feasible to fully exploit the capabilities of PUMs due to the lack of model-based torque control systems. This research will eliminate the barrier to PUM adoption and lead to model-based torque control algorithms and driver hardware. The key result of the Phase I STTR will be demonstration of the feasibility of model-based torque control of PUMs using a passive inertial load. This result will provide assurance that the overall project result, development of model-based torque control hardware and software, is both feasible and attainable. This result will be achieved via the development of a mathematical model relating motor input parameters and speed to output torque and experimental validation of the model. This Phase I STTR will also produce a design for an enhanced laboratory apparatus incorporating an active load, thus permitting detailed modeling of the space-based robot actuation environment.