Experiments in real-time collision avoidance for dexterous 7-DOF arms

A new approach to real-time collision avoidance for dexterous 7-DOF arms and supportive simulation and expem”mentai results are presented. 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 bg employing an outer feedback loop which perturbs the arm Cartesian commands for the inner position control system. Graphical simulation results are presented to demonstrate the application of the collision avoidance approach to the dexterous 7-DOF arms of the NASA-Ranger Telerobotic Flight Experiment. The approach is also implemented and tested on a 7-DOF RRC arm and a set of experiments are conducted in the laboratory. These experiments demonstrate perturbations of the end-eflector position and orientation, as well as the arm posture, in order to avoid impending collisions. The proposed approach is simple, computationally fast, requires minimal modification to the arm control system, and applies to whole-arm collision avoidance.