In this paper, a novel force sensing method is proposed to achieve a wideband force control system with friction-free and noise-free observation. The effect of friction on force observation is eliminated owing to the addition of a periodic signal to the desired reference signal. A high-order disturbance observer and a Kalman filter are used for the force-sensing operation to reject the oscillatory disturbance and to suppress the noise in force estimation. In consequence of effective noise reduction using the Kalman filter, the force sensing bandwidth improves radically. Additionally, all the control algorithms are implemented in a field-programmable gate array (FPGA) with a high sampling rate; the FPGA enables the widening of the bandwidth of the force control system. The effectiveness of the proposed method is verified by experimental results.
2012 The Institute of Electrical Engineers of Japan