Collision detection for collaborative assembly operations on high-payload robots

Human-robot collaboration for high-payload industrial applications has the potential to unlock new applications and improve operator ergonomics. However, ensuring safety with closer proximity remains challenging due to the large payload. Collision detection can improve safety, but must be modified to consider the dynamics of high payload applications (internal oscillation, effective low-pass filtering of external force), while the higher inertia raises questions about the resulting collision forces. This paper proposes the first collision detection approach for high-payload applications, using a force/torque sensor at the end-effector and motor current measurements for redundancy to be compliant with ISO/TS 15066:2016. Analysis of a linear model informs the design of the detection algorithm and effect of higher payload. Experimental validation shows feasibility and performance of collision detection over a range of motion and payload conditions, and the impact of the safety system in improving an industrial use-case.