Analysis and compensation in specific frequency based on composite filter for nanoscale motion control

Nanoscale motion control is required for miniaturization and performance improvement of mechatronics systems. In motion control at nanometer scale, disturbances which do not affect the system at macro scale might greatly influence the control performance. The torque ripple caused by distortion of current is one of the most serious disturbance elements and should be eliminated. To address this problem, the method of the filter designing is proposed in this paper. The effect of the distortion of the current can be reduced by designing the filter in disturbance observer to have low-pass filter and band-stop filter. This paper shows the design method and the stability of force control based on the composite filter. By using high-precision acceleration control based on the proposed method, persistent oscillation can be suppressed, control accuracy can be improved. The validity of the proposal is confirmed by experiments.