A Low-cost Inchworm-inspired Soft Robot Driven by Supercoiled Polymer Artificial Muscle

Abstract

This paper presents a novel design of soft locomotion robot inspired by inchworm. This robot is actuated by supercoiled polymer artificial muscle (SCPAM), which are made from low-cost conductive nylon sewing threads. SCPAM generate muscle-like actuation upon heating and cooling, which can be utilized for soft locomotion robot's actuation. The proposed soft robot realizes inching locomotion by introducing friction anisotropy in its legs and contraction provided by SCPAM. Experiments are performed to evaluate the soft robot body's deformation as well as the robot's locomotion velocity when SCPAM are at different power input levels. Results exhibit that the soft robot can achieve locomotion velocity of 0.245 mm/s on the wood ground when SCPAM is powered at 0.16 W/cm. Compared to previous studies utilizing fluidic actuator, shape memory alloy (SMA) or motor & tendon for actuation of soft locomotion robot, SCPAM possesses high power-to-weight ratio, inherent compliance and low cost, making the robot more compact and more suitable for field exploration in contaminated areas. This study shows the potential of this low-cost artificial muscle to be widely used in soft locomotion robots in the future.