Design and Modeling of a Multi-joint Reinforced Soft Pneumatic Actuator

In order to improve the tip force and controllability of soft pneumatic actuator (SPA), this paper presents the design principle and mathematical modeling method of a multi-joint reinforced soft pneumatic actuator (MRSPA). The MRSPA is composed of an equivalent three driven joints and a spring leaf on the bottom of the MRSPA. Through finite element analysis (FEA), the influence of different chamber distribution on the bending performance of a single joint under the same length is explored. In addition, a mathematical model is established to explore the relationship between pressure, load and bending angle of the driven joints and to estimate the curved configuration of the MRSPA. The FEA results show that the uniform chamber distribution is easier to enable the two-way bending of the SPA. The mathematical model of the MRSPA is validated by comparing the simulation results based on the mathematical model with the FEA results. The main contribution of this paper is to establish a mathematical model to estimate the tip force and configuration of the MRSPA at the same time.