Controller design for dual-stage actuator of load devices considering of resonant vibration suppression due to input saturation

This paper presents a controller design approach considering vibration suppression due to input saturation for load devices. In the target load device, a pneumatic actuator and a voice coil motor are combined as a dual-stage actuator to expand the servo bandwidth. However, since vibrations are excited by the input saturation in the voice coil motor, the vibrations deteriorate the force tracking performance for the desired load reference. In this research, therefore, a loop-shaping approach is adopted to suppress the vibrations, where a compensator is designed to improve the disturbance suppression performance at the resonant frequency of plant. The proposed approach has been verified by experiments using a prototype of load device.