Robust Impedance Shaping of Redundant Teleoperators with TimeDelay via Sliding Mode Control This paper presents a robust impedance shaping controller for teleoperation systems. An integral sliding mode control law (ISM) is employed together with standard robot inverse dynamics to reject disturbances and uncertainties acting on the robot model and obtain an ideal fullydecoupled system. Higher level optimizationbased controllers are responsible for enforcing the desired end effector impedance on master and slave manipulators, as well as for solving possible kinematic redundancies and satisfying control constraints. A threeplusone channel teleoperation architecture is proposed, with an indepth analysis of its stability and transparency properties in presence of variable communication delays, based on Llewellynxe2x80x99 s absolute stability theorem. Impedance parameters tuning criteria are derived and the proposed scheme performance is compared in simulation with a timedomain passivity approach. The validation of the proposed controller is carried out on a ABB YuMi dualarm redundant robot, with one arm employed as a master and the other one as a slave device.

Dual Closedloop Impedance Control for Wheeled Mobile Manipulator in Trajectory Tracking This paper presents a dual closedloop impedance control scheme for a nonholonomic wheeled mobile manipulator in trajectory tracking with nonlinear contact disturbance. The kinematics and dynamics models of the mobile platform and nlinks manipulator are established based on the EulerLagrangian approach. In order to control and eliminate the influences caused by system uncertainties and nonlinear contact disturbance, a control scheme which consists of double closed loops is proposed. The impedance control is applied to realize force tracking control in the outer loop. The inner loop is then designed to deal with chattering of measured parameters by using extended Kalman filter. The proposed controller ensures the tracking error in workspace converges to zero and the input torques are smooth. Utilizing the Lyapunov method, the stability of the system is proved. Simulation compared with conventional control methods on two driving wheeled mobile manipulator shows the effectiveness and robustness of the proposed control scheme.