Improved Model of the PWM Driven 3/2 Solenoid Valve Pneumatic System for Soft Pneumatic Actuators

Soft pneumatic actuators (SPAs) are the building blocks of soft robots that are characterized by their inherent compliance, high degree of dexterity, and safety in human-robot interaction. The non-linear dynamics of the pneumatic system and elastomeric material deformation in SPAs presents a challenge in developing control systems for these actuators. Therefore simulations are often used to aid in the design and validation of new control schemes for SPAs. Pressure control is an important aspect of achieving precise motion control of the SPA.This paper presents an improved simulation model for a SPA pneumatic system that utilizes a 3/2 solenoid valve. The model was implemented using the SimScape Fluids toolbox in MATLAB. The proposed simulation model builds on existing models by accounting for the 3/2 solenoid valve dynamics. The open-loop response of the improved model was compared with the previous model and experimental data. The results showed that the improved model was more representative of the real-world performance of the system under open-loop control.