DNA-Structured Linear Actuators

Abstract

This work presents a series of DNA-structured linear actuators that have high displacements and compact profiles. These actuators operate by twisting and untwisting a double helix that resembles a DNA molecule. Unlike most similarly-motivated twisted string actuators (TSAs), these DNA-structured actuators can have the ability to exert both push and pull forces on a load. Thus, although originally designed for cable-driven robotics, these actuators have the ability to work as part of many different mechatronic systems. Two inherently different actuator designs were investigated, one with straight-line edges (rails) and one with helical rails. Two mathematical models of angular rotation versus linear displacement were developed and simulated, one for each design, and three prototypes were constructed to validate the models. The final prototype was tested for displacement, restorative torque, and pull force characteristics. This last prototype showed a 30.5 cm stroke for a 40.5 cm actuator, or a displacement of 75.3% of its total length.