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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.

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Deformable object manipulation (DOM) is an emerging research problem in robotics. The ability to manipulate deformable objects endows robots with higher autonomy and promises new applications in the industrial, services, and healthcare sectors. However, compared to rigid object manipulation, the manipulation of deformable objects is considerably more complex, and is still an open research problem. Tackling the challenges in DOM demands breakthroughs in almost all aspects of robotics, namely hardware design, sensing, deformation modeling, planning, and control. In this article, we highlight the main challenges that arise by considering deformation and review recent advances in each sub-field. A particular focus of our paper lies in the discussions of these challenges and proposing promising directions of research.

This paper presents the development and evaluation of concurrent control of a robotic system for less-invasive treatment of osteolytic lesions behind an acetabular implant. This system implements safety constraints including a remote center of motion (RCM), virtual walls, and joint limits while operating through the screw holes of the acetabular implant. The formulated linear constrained optimization problem ensures these constraints are satisfied while maintaining precise control of the tip of a Continuum Dexterous Manipulator (CDM) attached to a positioning robot. Experiments evaluated the performance of the tip control method within an acetabular cup. The controller reliably reached a series of goal points with a mean error of 0.42 mm and a worst-case error of straying 1.0 mm from our path.