Position and force tracking in nonlinear teleoperation systems with sandwich linearity in actuators and time-varying delay

In this paper, a new bounded force feedback control law is proposed to guarantee position and force tracking in nonlinear teleoperation systems in the presence of passive and nonpassive input interaction forces, time varying delay in their communication channels and sandwich linearity in their actuators. The proposed control is a nonlinear-proportional plus nonlinear damping (nP+nD) controller with the addition of a nonlinear function of the environment force on the slave side and nonlinear function of the human force and force error on the master side, the transparency of the proposed scheme will be improved. The controller prevents the inputs from reaching their usual actuator bounds. Using a novel Lyapunov–Krasovskii functional, the asymptotic stability and tracking performance of the teleoperation system are established under some conditions on the controller parameters, actuator saturation characteristics and maximum allowable time delays.