Soft Robotic Gripper Using Phase-Change Material Elastomer Composite Actuator

Abstract

A pneumatic system-driven soft gripper is a classic type of soft robotics with several promising features, including light weight, affordability, ease of fabrication, and simple control. The working principles of the pneumatic soft robot gripper are simple. The fingers of the gripper consist of a rubber structure that is often reinforced with fibers and contains an internal chamber or multiple chambers. Applying high pneumatic pressure to the chamber or chambers causes elastic deformations of the rubber structure, thereby functioning as actuators. However, adjusting the pressure by controlling the gas or liquid usually entails using pumps and complex mechanical components, such as a hydraulic cylinder, motor, and valve. This results in complexity and tediousness in the deployment process and environmental noise disturbances. In this study, we present a soft gripper for underwater operations that utilizes a Phase-change material–elastomer composite (PCMEC) actuator. This material can change the phase between liquid and vapor by joule heating or cooling. This feature enables the actuator to deform and return to its initial shape without the need for intricate mechanical structures or pumps. We assessed the deformation angle, speed of flexion, and temperature of the PCMEC actuator along with force performance, including touch and grip of the soft fingers.