High performance speed control for ultrasonic motors

A novel speed control for traveling wave type ultrasonic motors is presented and verified by measurements on a prototype drive, Based on an underlying bending wave control the nonlinear torque generation of the USM is compensated by an inverse contact model calculating the reference values of bending wave control under consideration of an optimized set point adjustment. For this task a basis function neural network is applied. By compensation of the nonlinearity the command behavior of the USM approaches that of conventional drives and proven speed control schemes can be implemented as further control loop, The novel speed control investigated offers excellent dynamic responses and is thus attractive for applications in the field of high performance servo systems.