Haptic transmission by weighting control under time-varying communication delay

Haptic transmission, which is realised by master-slave robots system, is a challenging research to extend human hands. However, the communication delay is a serious problem which degrades the performance and causes instability to the system. In this paper, a new bilateral control law with weighting control is proposed to achieve high-performance haptic transmission under varying communication delay. This method weights the force control and the position control in the master robot according to the estimation of environment stiffness in the slave one. A virtual spring is proposed and inserted into the stiffness estimation algorithm to guarantee the availability for hard environment. The stability is analysed by considering the passivity of the master-slave robots system under the proposed control law. Finally, the validity of the proposal is confirmed by experiments.