Modelling Analysis of a Soft Robotic Arm Based on Pneumatic-Network Structure

Abstract

As an important supplement of rigid robotic arms, soft robotic arms have infinite degrees of freedom theoretically and can realize more flexible movement. Soft robotic arms have a broad application prospect in the fields of man-machine cooperation, medical rehabilitation training, space and underwater exploration, etc. In this paper, a kind of soft robotic arm based on pneumatic-network structure was proposed. Each soft robotic arm module adopts three symmetrical and independent pneumatic-network cavity structures, and can realize axial extension and spatial bending motion after driving three cavities respectively. Based on the assumption of constant curvature and the theory of large deformation of beam, the bending model and elongation model of module motion were established. Moreover, considering the influence of its own gravity on bending performance, the bending models of single-module soft robotic arm were modified. Then, we built an experimental platform to test the bending and elongation motion of the soft robotic arm module, and compared the experimental results, simulation results and theoretical model results. It is shown from the experimental results that when the inflation pressure is in the range of 0 ~ 80 kPa, the model results are close to the simulation results and experimental results. In this paper, the structural and theoretical basis for the follow-up research is laid, which shows that the soft robotic arm based on pneumatic-network structure has broad application prospects.