Rigid robots can be precise in repetitive tasks, but struggle in unstructured environments. Nature's versatility in such environments inspires researchers to develop biomimetic robots that incorporate compliant and contracting artificial muscles. Among the recently proposed artificial muscle technologies, electrohydraulic actuators are promising since they offer performance comparable to that of mammalian muscles in terms of speed and power density. However, they require high driving voltages and have safety concerns due to exposed electrodes. These high voltages lead to either bulky or inefficient driving electronics that make untethered, high-degree-of-freedom bio-inspired robots difficult to realize. Here, we present hydraulically amplified low voltage electrostatic (HALVE) actuators that match mammalian skeletal muscles in average power density (50.5 W kg-1) and peak strain rate (971 % s-1) at a driving voltage of just 1100 V. This driving voltage is approx. 5-7 times lower compared to other electrohydraulic actuators using paraelectric dielectrics. Furthermore, HALVE actuators are safe to touch, waterproof, and self-clearing, which makes them easy to implement in wearables and robotics. We characterize, model, and physically validate key performance metrics of the actuator and compare its performance to state-of-the-art electrohydraulic designs. Finally, we demonstrate the utility of our actuators on two muscle-based electrohydraulic robots: an untethered soft robotic swimmer and a robotic gripper. We foresee that HALVE actuators can become a key building block for future highly-biomimetic untethered robots and wearables with many independent artificial muscles such as biomimetic hands, faces, or exoskeletons.

翻译：刚性机器人在重复性任务中表现精准，但在非结构化环境中则存在困难。自然界在此类环境中的多变性启发研究者开发仿生机器人，其整合了柔顺且可收缩的人工肌肉。在近期提出的人工肌肉技术中，电液压驱动器因在速度和功率密度方面性能堪比哺乳动物肌肉而备受关注。然而，它们需要高驱动电压，且裸露电极存在安全隐患。这些高电压导致驱动电子器件要么体积庞大，要么效率低下，使得实现无绳、高自由度的仿生机器人变得困难。本文提出液压放大低压静电（HALVE）驱动器，在仅需1100V驱动电压下，其平均功率密度（50.5 W kg⁻¹）和峰值应变率（971% s⁻¹）与哺乳动物骨骼肌相匹配。该驱动电压相较于其他使用顺电介质的电液压驱动器降低了约5-7倍。此外，HALVE驱动器触感安全、防水且自清除，易于在可穿戴设备和机器人中实现。我们对该驱动器的关键性能指标进行表征、建模和物理验证，并将其性能与现有最优电液压设计方案进行对比。最后，我们通过两个基于肌肉的电液压机器人——无绳软体游泳机器人和机器人夹爪——展示了驱动器的实用性。我们预见HALVE驱动器将成为未来高度仿生无绳机器人和可穿戴设备的关键构建模块，例如仿生手掌、面部或外骨骼中众多独立人工肌肉的核心组件。