Wireless Electrohydrodynamic Actuators for Propulsion and Positioning of Miniaturized Floating Robots

Autonomous soft robots require compact actuators generating large strokes and high forces. Electro‐fluidic actuators are especially promising, they combine the advantages of electroactive polymers (low‐power consumption, fast response, and electrical powering) with the versatility of fluidic systems (force/stroke amplification). EHD (electrohydrodynamic) actuators are electro‐fluidic actuators whose motion results from charges being induced and accelerated in a liquid. They are extremely compact, silent, and low power (≤10 mW). They have been recently demonstrated in stretchable pumps and for the wireless propulsion of simple floating robots. This study demonstrates simultaneous wireless propulsion (2.5 mm s−1) and control of a 1 cm sized robot using a single DC signal. Voltage is applied between an electrode on the floating robot and a fixed one, both exposed to a dielectric liquid. Results support the underlying physical mechanism as EHD and characterize robot motion with different fluorocarbon liquids and voltages between 400 and 1800 V. Path following is demonstrated with a 3 × 3 array of electrodes. EHD actuators prove to be a simple, compact, low power alternative to magnetic and acoustic actuators for wireless powering and control of miniaturized robots, with applications in precision assembling at the micro/mesoscale, lab‐on‐chip, tactile displays, and active surfaces.