Towards safe physical human-robot interaction: An online optimal control scheme

Operating in the proximity of humans has been a long-term challenge in robotics research. To achieve this objective, one of the main issues is to ensure safe and comfortable physical human-robot interaction (pHRI). In this paper, we tackle the safety problem at the control level. To ensure operation is within perceived safe zone, we use model predictive control, which finds the optimal control signal online, while imposing predefined safety constraints on the robotic system. The strength of this method lies in allowing the system to perform close to, or at the edge of the constraints´ boundaries. In contrast to other works we consider here perceived safety; the constraints for perceived safety are derived in a competitive pHRI experiment. The perceived safety and comfort of the proposed approach is then evaluated with a second, game-like pHRI experiment.