A Centrifugal Force-Based Configuration-Independent High-Torque-Density Passive Brake for Human-Friendly Robots

Safe actuation is one of the most important requirements for human-robot collaboration. Although a variety of passive brakes have been developed in order to safely regulate joint velocities, their performances are significantly subjective to gravity direction and mounting position, and thus are not suitable for multi-degrees of freedom (DoF) robotic applications. Addressing these issues, we developed a centrifugal force-based configuration-independent high-torque-density passive brake. The brake is rapidly and bidirectionally activated at the desired velocity limit in any orientation relative to the direction of gravity. A design optimization methodology is proposed for high-torque density and low-reflected inertia, which allows for inherent safe actuation in the event of a system failure. Experimental results demonstrate that the proposed brake is an effective solution for limiting velocity in multi-DoF human-friendly robots.