Jamming of Granular Media as a Variable Stiffness Mechanism to Enable Robust, Low-cost, and Highly Articulated Robotic Manipulators

A continuum style manipulator is actuated by jammable media within an envelope of a module, which is also actuated by a tensile element, such as a cable and spooler motor. Multiple modules may be reversibly added. Two or more tensile elements may also be used. Three or more actuated tensile elements can actuate three DOFs of each module, and the terminal module, as well as the entire manipulator. Jammable media may be granular, actuated by a pressure change. Coarsely ground coffee works well. Rather than a jammable media, tensile elements may alternatively be used with other phase change media, such as magnetorheological and electrorheological media. A high friction angle of the granular media is desirable, and has been achieved with a particle size dispersion including both small and relatively larger particles. Applications include endoscopes, proctoscopes, laparoscopic instruments, manufacturing and medical manipulators. Methods of actuating include unjamming all modules, positioning the manipulator with tensile elements or otherwise, jamming the base-most module, and then repositioning remaining, not-jammed modules, followed by jamming the base-most not-jammed module, and so on, until all modules are positioned and jammed.