Abstract:The existing four-channel bilateral control teleoperating system based on disturbance observer (DOB) can achieve a certain degree of transparency without relying on force sensors. However, the current master/slave controller design is mostly based on the trial and error method, lacks systematic design, and is limited by the DOB operating bandwidth, so transparency cannot be improved. In this work, a systematic method for designing controllers based on robust control theory is proposed. The teleoperated four-channel bilateral control is transformed into two general feedback control systems by obtaining the dynamic equations of the position response error and disturbance residual between the master/slave robot, then systematically integrated controller can be obtained through selecting appropriate weighting functions based on H∞ control theory. The new method presents a general method to realize the bilateral control of master/slave robot under the condition of forceless sensor. Experiments show that the controller designed via the systematic method can ensure the system stability and transparency, and improve the tracking and force transfer between two motors. Besides, this design exhibits stronger robustness to disturbance and model uncertainty in the system compared with the traditional four-channel bilateral control based on PD control design.