Robust Adaptive Force Tracking Impedance Control for Robotic Capturing of Unknown Objects

The manipulation for space known objects has been studied extensively, however, the case for unknown objects still needs further investigation because there is little information to assist measurement and manipulation. This paper proposes a robust adaptive force tracking impedance controller for robotic capturing of space unknown objects, which has a great adaptability to the environmental parameters of the objects, a force tracking capability of capturing different types of space objects, and robustness to uncertainties. First, the position control based impedance control scheme is given. Second, an environmental parameters adaptive law is designed to estimate the environmental location and the stiffness of the grasped object. Third, by using the nonlinear high-gain tracking differentiator (HGTD) and linear extended state observer (LESO), a robust adaptive dynamic surface position controller for a space robot is proposed to guarantee a good position tracking performance of the controller and the robustness to system’s parametric uncertainties. At last, numerical simulations are conducted to demonstrate the position/force tracking control performance of the proposed impedance control scheme.