A Novel Tendon-Driven Articulated Continuum Robot with Stabilized Self-Locking Joints

Articulated continuum robots (ACRs) are characterized by flexibility, controllability, and adaptability and perform excellently in complex and constrained environments. However, the large number of motor drives limit the ACRs' portability and make them cumbersome to control. This paper presents a novel tendon-driven ACR composed of stabilized self-locking joints (SLJs) connected in series. After triggering the mechanical constraints with shape memory alloy coils, each joint can be maintained in either a self-locking or release state with zero power consumption. Consequently, even with a single set of drive units, the ACR can operate in multiple modes, enabling variable motion performance and workspace adaptability, effectively reducing the number of motors. The ACR's stiffness also varies with the locking state of its SLJs, and no motor drive is required to maintain its shape when all SLJs are self-locking. The performance and reliability of the SLJ prototype were validated. The workspace of the ACR prototype model was analyzed, and its partial motion performance, motion error, and variable stiffness were verified.