A soft robotic exoskeleton utilizing granular jamming

Abstract

This paper presents the development and design of an exoskeleton for the hand, utilising a physical phenomena known as granular jamming, where pressure within a soft membrane is varied to cause a granular material to change from a solid to fluid-like state. Experimentation and simulation is performed to discover and analyse the relationship between chamber size and the generation of resistive forces or bending stiffness, and to observe the general behaviour of granular beam systems under bending forces. A prototype was developed and tested. It was found that increasing the chamber size of a jammed granular beam increases the generated resistive forces. There also appears to be two regions of bending for a jammed granular beam identified by a change in gradient on a graph of deflection versus weight. This indicates a change in the granular structure during bending and is theorised to be caused by two mechanisms, buckling and longitudinal strain. The prototype indicates that the exoskeleton is functional and is able to stabilise the hand, but fails to provide significant force. The work done in this project can be used as a foundation for further design and investigation.