Force sensation improvement in bilateral control of different master-slave mechanism based on high-order disturbance observer

In this work, we present a bilateral control system with different mechanisms of master and slave sides. A linear shaft motor and a ball screw perform the roles of the master and slave, respectively. To reduce the friction effect on force estimation due to the ball screw mechanism, a periodic signal is inserted into the control signal of the slave side. The addition of periodic signal causes oscillatory force responses on both master and slave sides. Therefore, a high-order disturbance observer is designed for force sensing operation on the slave side to reduce the effect of oscillatory disturbance on force information. The control algorithm consists of a conventional disturbance observer and a high-order disturbance observer for master and slave sides, respectively. The numerical simulation results verify the effectiveness of the proposed method.