Design and Testing of a Soft Robot with Variable Stiffness Based on Jamming Principles

Abstract

A soft robot has high flexibility when performing tasks with moving and high stiffness, so it has important application in exploring and detecting complex environments. Based on the advantages of driving Pneu-Net and driven jamming mechanism, a soft robot with real-time variable stiffness and dynamic modeling methods is proposed. Firstly, the model of the soft actuator coupling pneumatic structure and jamming mechanism is established. Secondly, by using Hertzian contact model, a mathematical model of robot motion and theoretically investigated formation mechanisms of variable stiffness is built. Moreover, the pneumatically-driven structure is analyzed by using the finite element as well as the influences of pressure in cavities, considering shape and size of cavities on the bending angle of the soft robot are studied. Based on this, the pneumatically-driven structure is optimized. Finally, A prototype and testing of the soft robot arm with variable stiffness is implemented, which verified the variable stiffness and motion performances of the soft actuator. This study provides new theoretical and technical support for the design and stiffness control of a soft robot with variable stiffness.