Steven Zhang1,Soo Jin Adrian Koh1,Philipp Rothemund1,Toshihiko Fukushima1,Sophie Kirkman1,Christoph Keplinger1,2
Max Planck Institute for Intelligent Systems1,University of Colorado Boulder2
Steven Zhang1,Soo Jin Adrian Koh1,Philipp Rothemund1,Toshihiko Fukushima1,Sophie Kirkman1,Christoph Keplinger1,2
Max Planck Institute for Intelligent Systems1,University of Colorado Boulder2
Energy efficiency of actuators is a critically important metric for untethered and mobile robotic systems. The field of soft electrostatic actuators is missing an universal, easy to use tool and a standard that allow measurement and analysis of actuator’s intrinsic electrostatic-mechanical efficiency. Thus, in this work, a method to measure and optimize the efficiency of soft electrostatic actuators is developed, where the four work conjugate parameters: voltage, charge, force, and displacement, can be monitored in real time. The full cycle efficiency of electrostatic actuators can be calculated by dividing the area enclosed in the force-displacement plane and the area enclosed in the chargevoltage plane. We demonstrate our method using HASEL actuators as a model system, and the intrinsic electrical and mechanical losses were studied, and efficiency was calculated at different driving voltages and loads. It was found that there is an optimal load resulting in an efficiency of 58% for HASEL actuators. The method can be further used to study the impact of various parameters such as frequency, and the use of new materials systems and geometries on the efficiency.