A Comparative Dependability Analysis of Antagonistic Actuation Arrangements for Enhanced Robotic Safety

In this paper we introduce an analysis of dependability of an elementary yet critical component of robotic systems designed to operate in environments shared with humans, i.e. the joint-level actuation system. We consider robot joints that implement the Variable Impedance Actuation (VIA) paradigm. The VIA has been demonstrated to be an effective mean to achieve high performance while constantly keeping injury risks to humans by accidental impacts below a given threshold. The paper describe possible implementations of the VIA concept which use the Antagonistic Actuation (AA) in three different arrangements. This study follows a previously reported paper dealing with safety. Here a detailed comparative dependability and performability analysis in front of possible specific failure modes is conducted, whose results provide additional and useful guidelines for design of safe and dependable actuation systems for physical human-robot interaction.