A Novel Obstacle Collision Avoidance Strategy for Redundant Manipulator using Swivel Motion Control

The research of humanoid 7-DoF redundant robotic manipulator has attracted increasing attention, due to its importance of using the redundancy to accomplish sub-tasks. In this paper, a novel obstacle collision avoidance strategy is proposed for the redundant manipulator. At first, a controller of swivel angle defined by a plane consists of the robot's shoulder, elbow and wrist joints is designed. Then, a null space based controller is developed to avoid a moving obstacle by controlling the swivel angle's motion. The designed swivel motion controller is not only to guarantee the end-effector tacking the desired trajectory precisely but also to accomplish obstacle avoidance task in the sub-space with the virtual repulsive force pushing from the obstacle to the swivel joints. The feasibility of the proposed control strategy is proved by simulation experiments based on a 7-DoF redundant robot.