A continuum manipulator with phase changing alloy

A new type of cable-driven continuum manipulator (CM) is presented, in which the stiffness of the device along its body length can be controlled using the thermomechanical properties of a phase changing alloy. The liquid phase of the alloy is used for achieving high dexterity and the solid phase for high stiffness. Joule heating and water cooling is used for transitioning the phase changing alloy between stiff and compliant states. Single-segment and two-segment working prototypes of the CM are demonstrated. The mechanical and thermodynamic features of these prototypes are discussed and their physical performance is investigated. Advantages of the presented design with phase changing alloy include: significantly improved dexterity, high payload to weight ratio, controllable stiffness, energy efficiency, and a large lumen.