We propose a safety control approach based on the online optimal scaling of the size of bounding volumes used as dynamic safety zones for collaborative robotics. Intersection tests between bounding volumes surrounding robot and human allow the safety controller to identify possible collisions. Our proposed approach optimizes online smooth stop trajectories, to be engaged if a potential collision is detected. Unlike other approaches, the robot dynamics and its torque constraints are here considered to plan optimal trajectories that minimize the size of safety zones surrounding the robot. Simulation results on a validated model of a robot with seven degrees-of-freedom verify the feasibility of the proposed approach.
