A Novel Soft Actuator Based on Mini DC Motor and Supercoiled Polymer Artificial Muscle

This paper describes a novel design of a soft actuator that combines two types of actuation methods: DC motor actuation and supercoiled polymer (SCP) artificial muscle. SCP artificial muscle is used to substitute the traditional cable and attached to the gearmotor. The hybrid actuator intends to alleviate the drawbacks of both actuation methods. This novel actuator features a fast actuation speed and the addition of SCP artificial muscles endow it with a certain degree of compliance. At the same time, the thermal contraction property of SCP artificial muscle can also increase its output force. A soft robotic finger is designed to conFigure the actuator in it. In the experiment section, finger’s stiffness and output force tests are performed under three different actuation methods (single SCP/gearmotor & kite line/gearmotor & SCP). Experiment results demonstrate the superiority of this novel actuator in terms of compliance (compared with gearmotor & kite line actuation), actuation speed, and output force (compared with single SCP actuation). This actuator has the potential to be used for grasping and manipulation of soft robots in the future.