Reconfigurable Tendon-Driven Robots: Eliminating Intersegmental Coupling Via Independently Lockable Joints

The tendon-driven robot (TDR), with its slender redundant body, offers a large workspace and strong maneuverability in complex environments. It consists of multiple tendon-driven segments, where increasing the number of segments enhances dexterity and workspace but also intensifies intersegmental coupling. Therefore, achieving precise TDR control requires more complex models and additional motors. This work presents a concept of reconfigurable TDR (RTR), which is a special type of TDR equipped with innovative lockable joints. Each RTR joint can be individually locked or freed via antagonistic tendons, allowing selective actuation of segments and fundamentally eliminating inter-segmental coupling, thus avoiding complex coordinated control. Compared with the existing related studies, this work not only proposed a novel design of lockable joint and actuation module for RTR but also gave out the derivation of general kinematic and static models of RTR. In addition, the exploration of RTR on dexterity has been conducted. Furthermore, demonstrations using a seven-joint RTR prototype were conducted to show its reconfigurability and locomotion capability in complex environments with the proposed actuator module comprising only six motors.