Actuation Design of Tendon-Driven Arms

Robotic manipulators for aerospace missions must stay lightweight while remaining dependable in remote and hazardous environments. To meet these constraints, we introduce Time-Division Multiplexing Actuation (TDMA), a practical actuation strategy for tendon-driven robots that reduces the number of actuators without sacrificing torque output or fault tolerance.

TDMA is built around a vertically stacked rotational selection mechanism that combines self-rotating TDM motors for fast reconfiguration, electromagnetic clutches for sub-0.1 second engagement, a worm gear reducer for high load capacity and self-locking, and a dual-encoder design for accurate long-term positioning. Using this hardware, the MuxArm platform achieves a self-weight of 2.17 kg, supports a 10 kg actuator driving capacity, and maintains end-effector accuracy up to 1% of its length even under partial servo failure. We also develop an actuation-space trajectory planning method that enables fault-tolerant control and reduces tendon load by up to 50% compared with conventional approaches.