Safe and minimum-time path-following problem for collaborative industrial robots

Thanks to their reduced speed and payload, collaborative robotics are, in most of the cases, inherently safe when adopted in relatively simple applications. Other applications, however, still require quick robot movements and/or large payloads, while still taking advantage of sporadic human interventions. In these scenarios, robots are equipped with velocity monitoring capabilities and proximity sensors to reduce their speed as a function of the separating distance with the human worker. This paper presents a real-time methodology to steer a robotic manipulator along an assigned path in minimum time, while accounting for safety, according to the speed and separation monitoring clause of ISO TS 15066. The methodology has been compared against state-of-the-art research and commercial solutions, showing its outperforming capabilities. The outcome of experiments, which were performed on a COMAU SMART Six industrial robot, are also reported.