Design of tendon-driven mechanisms for fault tolerance from tendon-breaking by using centroid vectors

Tendon-driven mechanisms (TDMs) are mechanisms driven by more tendons than joints. This tendon redundancy is often used for changing the hardware compliance. In contrast, in this paper, the redundancy is used for coping with unexpected tendon breaking. We analyze kinematics of a class of TDMs with asymmetrically spanned tendons and modify it to design a TDM that preserves the controllability even if at least one of the tendons is broken. We validate the proposed method to design several TDMs.