Output-Feedback Adaptive Control of Networked Teleoperation System With Time-Varying Delay and Bounded Inputs

The output-feedback based controller design problem is investigated for the networked teleoperation system in this paper. A new control scheme is proposed to guarantee the global asymptotic stability of the bilateral teleoperation system with time-varying delays and bounded inputs. First, a new fast terminal sliding-mode velocity observer is proposed to estimate the unknown velocity signals for the teleoperation system. Then, by considering the unknown gravity term, an adaptive SP+Sd-type (saturated proportion plus saturated damping) controller is designed based on the estimated velocity. In the new controllers, the specific sigmoidal function is not used, and any one on a set of saturation functions can be applied. Furthermore, by choosing Lypunov-Krasovskii functional, we show that the master-slave teleoperation system is stable under specific linear matrix inequality conditions. With the given controller design parameters and the upper bound of the input, the allowable maximal transmission delay can be computed by using the proposed stability criteria. Finally, both simulations and experiments are performed to show the effectiveness of the proposed methods.