Safety Controller Synthesis for Collaborative Robots

Safety Controller Synthesis for Collaborative Robots Mario Gleirscher, Radu Calinescu Assuring Autonomy International Programme, University of Y ork, Y ork, UK Department of Computer Science, University of Y ork, Y ork, UK mario.gleirscher,radu.calinescu@york.ac.uk Abstract --In human-robot collaboration (HRC), software-based automatic safety controllers (ASCs) are used in various forms (e.g. Complex robotic tasks and increasingly close human-robot interaction pose new challenges to ASC developers and certification authorities. Key among these challenges is the need to assure the correctness of ASCs under reasonably weak assumptions. T o address this need, we introduce and evaluate a tool-supported ASC synthesis method for HRC in manufacturing. Our ASC synthesis is: (i) informed by the manufacturing process, risk analysis, and regulations; (ii) formally verified against correctness criteria; and (iii) selected from a design space of feasible controllers according to a set of optimality criteria. The synthesised ASC can detect the occurrence of hazards, move the process into a safe state, and, in certain circumstances, return the process to an operational state from which it can resume its original task. I NTRODUCTION An effective collaboration between industrial robot systems (IRSs) and humans [1], [2] can leverage their complementary skills, but is difficult to achieve because of uncontrolled hazards and unexploited sensing, tracking, and safety measures [3]. Such hazards have been studied since the 1970s, resulting in elaborate risk taxonomies based on workspaces, tasks, and human body regions [2], [4]-[10]. The majority are impact hazards (e.g. Addressing these hazards involves the examination of each mode of operation (e.g. I, a variety of safety measures [3] can prevent or mitigate hazards and accidents by reducing the probability of their occurrence and the severity of their consequences . There are functional measures using electronic equipment (e.g.