Robust bilateral teleoperation of a car-like rover with communication delay

This paper addresses bilateral teleoperation of a car-like rover with communication delay. The proposed teleoperation scheme enables change of linear velocity and steering angle of the rover by pushing and pulling a haptic joystick. An environmental force determined according to relative distances and speeds between the rover and obstacles is rendered to the human operator. The human operator perceives the environmental force via haptic feedback of the joystick to accomplish obstacle detection and avoidance, such that teleoperation performance is improved. A sliding-mode based impedance control is proposed for the slave robot. Stability of the closed-loop teleoperator is ensured by passivity of the impedance controlled master and slave robots, as well as absolute stability of the communication channel modeled as a 2-port network. The sliding-mode based impedance controller for the rover also ensures robustness in the presence of uncertain, time-variant dynamics of the robot, which are non-negligible for out-door and planetary applications. Preliminary experimental results have shown feasibility of the proposed teleoperation scheme.