Disturbance elimination of ultra-precision micro-motion platform by adaptive inverse approach

The low-frequency disturbance from the ground vibration has a significant effect on the accuracy of ultra-precision micro-positioning movement. To suppress the disturbance, this paper presents a disturbance cancellation scheme in which the adaptive inverse and the PID control are combined together. For the unstable system, the PID controller is used to stabilize the plant and to estimate the effect at the output of low frequency disturbances. Compensation signal is then introduced at input end by using adaptive inverse controller to eliminate the its effect. Simulation and experimental results show that the method can effectively suppress the low-frequency disturbance and significantly improve the steady-state tracking accuracy of the ultra-precision stage.