Real-Time Strategy for Obstacle Avoidance in Redundant Manipulators

A robot working in a space shared with humans and obstacles needs an obstacle avoidance strategy. In this work, a kinematic control algorithm of a redundant robotic system for real-time obstacle avoidance is presented. The workspace is populated by fixed and moving obstacles. To plan a trajectory in real time, an artificial potential field and a distance algorithm are introduced: an artificial force set, composed by an attractive force towards the goal and repulsive forces from the obstacles, drives the robot end-effector in the workspace; at the same time repulsive velocities act on control points along the links of the robot, avoiding contacts with obstacles all over the serial kinematic chain of the manipulator. The algorithm has been implemented in a 2D environment for a 3R planar manipulator in order to assess the algorithm and present preliminary results. The strategy presented in this study will be the starting point for a more complex problem in 3D space with a 7-DOF redundant manipulator.