Obstacle avoidance for redundant manipulators using the Compact QP method

In this paper, the Compact QP (Quadratic Programming) method is proposed to resolve the obstacle avoidance problem for a redundant manipulator. Moreover, the drift-free criterion is also considered when a redundant manipulator performs a repeated motion. Due to the computational efficiency and versatility of the Compact QP method, real-time implementation is able to be achieved, and physical limitations such as joint rate bounds and joint angle limits can be easily taken into account. An example is given to demonstrate that this method is able to avoid the throat of a cavity, and to remedy the drift problem while a primary goal of the manipulators is carried out. Simulation results show that multiple goals can easily be fulfilled by the Compact QP method. The CPU times for a four-link planar redundant manipulator is less than 2 ms, and not more than 5 ms for six-link one. It is believed that the Compact QP method can be applied to solve the obstacle avoidance problem effectively and efficiently.