High-Performance Sensorless Force Control Using Superior Wideband and Periodicity-Cancellation Force Observer

In this paper, a new force observation approach is proposed to realize a superior wideband and periodicity-free sensorless force control system. The proposed force observer is established by the periodicity estimation integrated singular spectrum analysis based disturbance observer. The singular spectrum analysis is designed to significantly separate the essential components of force estimation of the disturbance observer from extreme noise contamination. Accordingly, the bandwidth of the force sensing is considerably broadened at a highly increased pole of the disturbance observer. Additionally, to eliminate the superimposition of the undesired dither periodicity from the force sensation, the periodicity estimation is developed using the least squares method. The proposed method attains a superior widened force sensing bandwidth and high-performance force sensation. The effectiveness validation of the proposed method is performed through the experimental results of force control implemented in a ball-screw system.