Dynamic safety in collaborative robot workspaces through a network of devices fulfilling functional safety requirements

摘要

Safety in human-robot cooperation is a non-optional property of any modern robot manufacturing application. All actions and settings, in terms of hardware and software, are intended to prevent hazards. In the domain of workspace sharing, with Speed and Separation Monitoring (SSM) modes, some safety-critical components can rely on safety-rated localization of users and safe computation of kinematical entities. Common to sensing and algorithms, some core functions are likely to be distributed in a network of devices, not necessarily sharing a safety-rated fieldbus. On the computation side, floatingpoint algorithms are never performed in state-of-the-art applica-tions compliant with current regulation. The purpose of the paper is to discuss the use of unsafe devices and protocols for safety functions considering functional safety at system level. On top of that, realistic conditions in networking are directly affecting one of the principal parameters of safety, which is protection distances. Some experimental data are reported in the case of dynamic SSM, based on trajectory-dependent safeguarding volumes computed at runtime.