Comparison of the Hysteresis Response of Super-Coiled Polymer (SCP) Actuators

Abstract

In recent years, Super-Coiled Polymer (SCP) actuators have been investigated as a potential high yield and minimal cost alternative to bulky, power hungry and expensive conventional actuators. A major challenge however, has been finding appropriate general and industry uses for these actuators due to their nonlinear hysteretic response. This paper seeks to compare the hysteretic response for SCP actuators based on different thread weights and sizes and thus suggest possible directions for their use. The actuators were produced through coiling and heat treatment actuated via Arduino code and a microcontroller circuit. The hysteresis properties were obtained experimentally by supplying a controlled voltage to the system. The response was recorded via a camera and was then processed using MATLAB; the resulting displacement and strain were used to observe the hysteretic characteristics. These characteristics were used as the basis for recommending different applications for these SCP actuators. The results show single ply supercoiled polymers may be used in sensitive low stress applications, the triple ply and greater number of plies used in high stress applications, and the double ply used in applications that are sensitive but also have moderate stress requirements. It is recommended that this research into SCP actuators be furthered by developing hysteresis models for compensation, control and exploring their use in robotic systems and tactile mechanisms.