Safe Self-collision Avoidance for Versatile Robots Based on Bounded Potentials

Abstract

We present a novel and intrinsically safe collision avoidance method for torque- or force-controlled robots. We propose to insert a dedicated module after the nominal controller into the existing feedback loop to blend the nominal control signal with repulsive forces derived from an artificial potential. This blending is regulated by the system’s mechanical energy in a way that guarantees collision avoidance and at the same time allows navigating close to collisions. Although using well-known ingredients from previous reactive methods, our approach overcomes their limitations in respect of achieving reliability without significantly restricting the set of reachable configurations. We demonstrate the fitness of our approach by comparing it to a standard potential-based method in simulated experiments with a walking excavator.