Real-time collision avoidance for 7-DOF arms

The paper presents experimental results that demonstrate a new approach to real-time collision avoidance for 7-DOF arms. The collision avoidance problem is formulated and solved as a force control problem. Virtual forces opposing intrusion of the arm into the obstacle safety zone are computed in real time. These forces are then nullified by employing an outer feedback loop which perturbs the arm Cartesian commands for the inner position control system. The approach is implemented and tested on a 7-DOF RRC arm and a set of experiments are conducted in the laboratory. These experiments demonstrate perturbation of the end-effector position and orientation, as well as the arm configuration, in order to avoid impending collisions The approach is simple, computationally fast, requires minimal modification to the arm control system, and applies to whole-arm collision avoidance.