Granular Jamming

A variable stiffness, flexible manipulator enabled by granular jamming

The aim of this research is to build a variable stiffness snake-like robot for minimally invasive surgeries. To achieve variable stiffness in the manipulator, granular jamming was the chosen mechanism.

Our research focuses on optimizing the granular jamming system for the snake-like robot. To do this, we tested various sizes, shapes, and materials for the granules, as well as different designs and materials for the membranes.

To actuate the robot, we wrapped fibers around the granular jamming joints. Thus, while vacuum will jam the particles to rigidify the joint, inflating the membrane will cause the fibers to contract as a pneumatic muscle.


A. Jiang, G. Xynogalas, P. Dasgupta, K. Althoefer, and T. Nanayakkara, “Design of a variable stiffness flexible manipulator with composite granular jamming and membrane coupling,” IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2012), Vilamoura, Portugal, 2012.

A. Jiang, A. Ataollahi, K. Althoefer, P. Dasgupta, and T. Nanayakkara, “A variable stiffness joint by granular jamming,” ASME 2012 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC 2012), Chicago, IL, USA, 2012.

H.A. Wurdemann, A. Jiang, T. Nanayakkara, L.D. Seneviratne, K. Althoefer, “Variable Stiffness Controllable and Learnable Manipulator for MIS,” IEEE International Conference on Robotics and Automation (ICRA 2012) Workshop, St Paul, MN, USA, 2012.