Safety Controller Synthesis for Collaborative Robots

TL;DR

This paper presents a formal, tool-supported method for synthesizing safety controllers in human-robot collaboration, ensuring correctness and optimality to enhance operational safety in manufacturing environments.

Contribution

It introduces a novel ASC synthesis approach that is informed by process analysis, formally verified, and capable of hazard detection and safe process management.

Findings

The synthesized controllers can reliably detect hazards.

Controllers can safely transition processes to safe states.

The method ensures compliance with safety regulations.

Abstract

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.