  In human-robot collaboration (HRC), software-based automatic safety
controllers (ASCs) are used in various forms (e.g. shutdown mechanisms,
emergency brakes, interlocks) to improve operational safety. 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. To
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.
