Novel flexible mechanical actuator serving as an artificial muscle

Abstract

Most linear actuators (screw, pneumatic, hydraulic, etc.) consist of a stationary housing and a moveable (piston) extension component. In order to keep the piston constrained laterally, and due to other mechanical limitations, the pistons for these systems are incapable of translating more than the distance of the stationary housing. The relative translation distance is limited for those traditional linear actuators. In this study, a novel cable-driven linear actuator is designed that can provide both axial tension and compression forces, and be capable of extending to a final length that is over twice its original length. It uses a set of wires arranged in a helix configuration that extends or contracts axially due to a torsional rotation. These wires are constrained from shifting laterally and from buckling when under compression. Prototypes are constructed using mostly 3D printed components, and the relationship between the input torque, output force, and output contraction distance are determined experimentally.