On the Design, Analysis, and Experimental Validation of Pneumatically-Actuated, Soft Robotic, Telescopic Structures

Abstract

Soft robotics leverages highly elastic, deformable materials to enable sensitive human-centered applications in medicine, rehabilitation, and assistance, as well as industrial applications like robotic grasping and load-bearing. One particular type of soft robotic actuator - the pneumatically-actuated, soft robotic, telescopic structure (PASTS) - is a relatively new concept that utilises compliant material and geometry reminiscent of traditional telescopes to produce linear motion and force exertion. Previous works on telescopic soft actuators have focused on specific applications rather than fundamental mechanics, creating a clear knowledge gap in understanding their design, dynamics, and dependencies. This paper provides an in-depth study of the fundamental design parameters of soft telescopic actuators, and examines the impacts of certain critical dimensions and geometries on the physical behaviour and capabilities of these soft actuators. It revolves around the exploration of the influence of telescopic structure’s length, wall thickness and number of rings on its inflation and deflation behaviour, lifting and lowering speed, and motion smoothness. By experimentally verifying these relationships using several design variations, it demonstrates that telescopic structures are capable of repeatable linear extension within 0.85 mm of precision. It also determines the varying degrees±by which each critical parameter affects the desirable properties of the actuator, allowing for telescopic structures to be tailored and optimised for specific applications.