Efficient algorithms for the trajectory planning of redundant manipulators with obstacle avoidance

Abstract

This article presents a path planning strategy for redundant serial manipulators working in a cluttered environment. Developed in a practical context of telemanipulation, the algorithm, which sacrifices the capability of solving very difficult trajectories for efficiency, allows a human to control a robot at a higher level, in Cartesian space. The model of the environment is provided by a 3D vision system as an occupancy map. An iterative process guides the end effector towards its goal with the help of discrete potential fields, which reduce the number of local minima. The motion of the manipulator is calculated using the velocity inversion of a redundant manipulator, which optimizes the distance to obstacles. The algorithm includes joint limit constraints, collision detection and heuristics for the solution of typical difficult cases, thereby leading to a high success rate. A simulator has been developed to test the algorithms.