Safe human-robot cooperation through sensor-less radio localization

Adaptable workflows in human-robot cooperation (HRC) require a flexible sharing of the same workspace with major impact on human-centered robot motion planning. The standard EN ISO 10218 is fostering the implementation of hybrid production systems characterized by a close relationship among human operators and robots in cooperative tasks. A primary contribution in workers protection is given by real time monitoring of the entire workspace, including tracking of operators trajectories and tentative estimation of motion intentions. Operators localization has the purpose of enabling the Speed and Separation Monitoring (SSM) safety mode, as in draft ISO/TS 15066, and adapting the robot motion to approaching users. The present work discloses some preliminary results about methods of “sensor-less” localization of operators in industrial HRC scenarios, based on wireless sensor networks techniques. The proposed system is composed of a network of small, embedded RF transceivers pervasively distributed in fixed positions inside the robotic cell layout in order to localize the operators, who carry neither wireless active devices (device-free) nor specific tracking sensors (sensor-less sensing). Users positions over time are estimated from the perturbation of the radio field, considering the effect of the concurrently moving robots. Finally, the sensors-robots system is functionally integrated into a safety architecture.