Improving structural design of soft actuators using finite element method analysis

The latest progress in robotics includes the development of so-called soft robots. When it comes to actuation, most of the research in this field is strictly experimental, meaning that performance is observed a posteriori, on previously manufactured specimens. Although significant, results are often incidental and without a proper understanding of how the structure dictates properties of the soft robot. In this article, we propose a parametric modelling procedure of pneumatic soft actuator, in particular the Bellows-type actuator. Finite element method is used to analyse responses of the actuator to different topological changes in the structure. The initial structure of the actuator is represented with a set of parameters upon which simulation is performed. Results of these simulations give us insight into the nature of parameters, revealing which changes are desirable and which are not, depending on the different objectives set. By combining different parameters, the structure is improved in the sense of bending capability while stress in the material is even reduced. Particular attention was paid to the material modelling to achieve realistic results in the simulations.