New fuzzy reasoning-based high-performance speed/position servo control schemes incorporating ultrasonic motor

A high-performance servo control scheme using compact ultrasonic motors (USMs) as actuators has not yet been practically realized in modern industry and office automation systems because the dynamic and steady-state modeling of USMs is almost impossible from a theoretical point of view. A high-performance speed/positional servo control scheme based on modern fuzzy reasoning concepts and featuring a traveling wave-type USM with high torque at low speed range is presented. The control method of the USM servo system using inverter frequency and voltage control strategies for the speed and amplitude of the traveling wave on the USM stator and the phase difference control scheme between two-phase high-frequency inverters are demonstrated and evaluated using experimental results. In particular, the control implementation is described from a practical viewpoint. >