Design and Characterisation of a Muscle-Mimetic Dielectrophoretic Ratcheting Actuator

Abstract

The high potential impact of soft robotics is hampered by a lack of actuators that combine high-force, high-work and high-power capabilities, limiting application in real-world problems. Typically, soft actuators are tuned to an application by gearing -for example, trading power for strain. An example of a recently developed soft-actuator which exploits such gearing is the dielectrophoretic liquid zipping (DLZ) actuator. DLZs can produce large strains (>99%) and power densities comparable to biological muscles, but cannot achieve both in a single actuator. In this work, we introduce a muscle-mimetic DLZ ratcheting actuator (DLZ-R) that allows multiple DLZ-R heads to operate in parallel, thereby increasing force output without sacrificing stroke or power. We first characterise the effect of geometry on the performance of a 1-head DLZ-R, before demonstrating that the force, work, and power output of the DLZ-R scale linearly with the number of active DLZ heads. Next, we investigate the relationship between driving frequency and power output. Finally, we demonstrate a 12-head DLZ ratchet. We believe the DLZ-R represents a step towards soft actuators that can provide both high-work and high-power and the widespread use of soft technologies.

Low-voltage electrohydraulic actuators for untethered robotics

“…Decreasing the operating voltage of HASEL actuators is a key step to enabling highperformance, untethered soft robots. An approach to reducing voltages of HASEL actuators also has the potential to be applied to other electrohydraulic actuators (16,17,(21)(22)(23)(24)(25)(26).…”

RoboHeart: A Bi-Directional Zipping Actuator

“…A DLZ actuator consists of two flexible electrodes, covered with an insulating layer and separated by a thin layer of dielectric liquid. A range of DLZ architectures have been demonstrated including bow-ties [6], pumps [9], solenoids and recently ratchets [10]. In all cases, when high voltage is applied to the electrodes, electrostatic forces in the hinge region cause the electrodes to zip together.…”