Adaptive position/force control of coordinated multiple manipulators based on a new sliding mode

For the position/force control problem of multiple manipulators grasping a rigid object, an adaptive position/force control strategy is proposed based on a new sliding mode. With the Jacobian matrix, the joint space model for multiple manipulators can be converted into the task space model. In the process of controller design, we add the force error term into the sliding mode and design the position/force controller directly instead of decoupling the position and the force. The new position/force controller can make the force error converge to zero asymptotically, but the conventional controller can only guarantee it bounded. Considering the uncertainties of the dynamic model, adaptive control is introduced. The Lyapunov stability analysis demonstrates that the proposed strategy can guarantee the asymptotic convergence of position and force error. Simulation results of the two planar two-link manipulators are presented to validate the effectiveness and superiority of the proposed method in comparison with the conventional controller.