Collision-Free Trajectory Planning for Manipulator Using Virtual Force based Approach

This paper presents a virtual force based approach for real-time collision-free trajectory planning for manipulators. This approach defines a virtual attractive force to drive an end-effecter of a manipulator along a preplanned path and uses virtual repulsive force calculated based on 3-dimensional force field method (3D-F) to protect the whole robot arm. When all these external virtual forces are applied to a manipulator’s dynamic model, the wire model of the manipulator, which is modeled by using virtual joints with stiffness and damping, will move to the steady state of the manipulator’s dynamics model at the target point. At every time step, this approach outputs a pose or joint angles of the robot arm to the robotic manipulator controller to control the real robot arm through. Simulation results show that this approach can manage to find the trajectory of a robot arm in a very narrow environment without colliding into obstacles.