Mathematical Modelling and Sliding Mode Control of Squeezing-Tube-Driven Pump for Soft Robotic Applications

Research on pumping devices aiming at enhanced controllability and seamless integration with pneumatic actuators represents a key focus in soft robotics currently. In our previous work, a squeezing-tube-driven pump (STDP) was developed and experimentally validated to meet the application requirements of pneumatic soft robotics. In order to enhance the controllability of STDP and enable its application in complex robotic tasks, the development of available control methodologies remains an essential research objective. This article presents a mathematical analysis of the core actuating components (Archimedes spiral spring and elastic tube) of STDP. A comprehensive model of the tube compression is established. The sliding mode control method is employed to regulate the rotation speed of STDP. In addition, the pumping mathematical model for pressure regulation is developed under three pumping application scenarios: air pressure regulation, cylinder actuation, and pneumatic finger actuation. Experimental validation through systematic pumping trials demonstrates the effectiveness of the proposed control strategy in practical implementations.