A Lightweight Soft Gripper Driven by Self-Sensing Super-Coiled Polymer Actuator

This study proposes a soft gripper driven by a simple, lightweight, low-cost, self-sensing super-coiled polymer (SCP) actuator with a high power-to-weight ratio. SCP generates an untwisting motion when heated, and therefore, is suitable for designing the actuator. The actuator is fabricated with a multifilament sewing thread woven by the self-coiling method and yields a high output force. To enhance the accuracy of the actuator in measuring higher temperatures, we propose an improved temperature self-sensing method that uses a dedicated metal wire wound around the SCP. To provide a theoretical basis for the control of the actuator, we construct through experiments a thermoelectric model and a thermomechanical model for the SCP. The resulting kinematics of the soft gripper are analyzed, and a nested control system is established to realize a precisely control of the soft gripper. Finally, we build a prototype to test the grasping ability of the soft gripper.