Compliant Impedance Control for a Redundant Manipulator During Human Robot Interaction

Robot control with a compliant motion behaviour is important to guarantee the safety of human robot interaction. In this paper, we aim to guarantee the desired task impedance of the end-effector and to ensure a compliant behaviour of a redundant robot during human robot interactions. A task space impedance control scheme is proposed by designing a transferred impedance error, such that the robot end-effector can be governed to follow a target impedance model. Additionally, a low-priority controller is designed using the null space projection, such that compliant joint motion is guaranteed without affecting the main task. The stability of the whole system is illustrated using a conditional Lyapunov theorem. Simulation studies based on a plane redundant robot is carried out to demonstrate the validity of the proposed controller.