Soft underwater swimming robots actuated by smart materials have unique advantages in exploring the ocean, such as low noise, high flexibility, and friendly environment interaction ability. However, most of them typically exhibit limited swimming speed and flexibility due to the inherent characteristics of soft actuation materials. The actuation method and structural design of soft robots are key elements to improve their motion performance. Inspired by the muscle actuation and swimming mechanism of natural fish, a fast-swimming soft robotic fish actuated by a bionic muscle actuator made of dielectric elastomer is presented. The results show that by controlling the two independent actuating units of a biomimetic actuator, the robotic fish can not only achieve continuous C-shaped body motion similar to natural fish but also have a large bending angle (maximum unidirectional angle is about 40°) and thrust force (peak thrust is about 14 mN). In addition, the coupling relationship between the swimming speed and actuating parameters of the robotic fish is established through experiments and theoretical analysis. By optimizing the control strategy, the robotic fish can demonstrate a fast swimming speed of 76 mm/s (0.76 body length/s), which is much faster than most of the reported soft robotic fish driven by nonbiological soft materials that swim in body and/or caudal fin propulsion mode. What's more, by applying programmed voltage excitation to the actuating units of the bionic muscle, the robotic fish can be steered along specific trajectories, such as continuous turning motions and an S-shaped routine. This study is beneficial for promoting the design and development of high-performance soft underwater robots, and the adopted biomimetic mechanisms, as well as actuating methods, can be extended to other various flexible devices and soft robots.

中文翻译：

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由仿生肌肉驱动的快速游动的软机器鱼。


由智能材料驱动的软水下游泳机器人在探索海洋方面具有独特的优势，如噪音低、灵活性高、环境交互能力友好。然而，由于软驱动材料的固有特性，它们中的大多数通常表现出有限的游泳速度和柔韧性。软体机器人的驱动方法和结构设计是提高其运动性能的关键要素。受天然鱼的肌肉驱动和游泳机制的启发，提出了一种由介电弹性体制成的仿生肌肉致动器驱动的快速游泳的软机器鱼。结果表明，通过控制仿生致动器的两个独立驱动单元，机器鱼不仅可以实现类似于天然鱼的连续 C 形身体运动，而且具有较大的弯曲角度（最大单向角约为 40°）和推力（峰值推力约为 14 mN）。此外，通过实验和理论分析，建立了机器鱼游泳速度和驱动参数之间的耦合关系。通过优化控制策略，机器鱼可以表现出 76 毫米/秒（0.76 体长/秒）的快速游泳速度，这比大多数已报道的由非生物软材料驱动的软机器鱼在身体和/或尾鳍推进模式下游泳的速度要快得多。更重要的是，通过对仿生肌的驱动单元施加编程电压激励，机器鱼可以沿着特定的轨迹进行引导，例如连续的转动运动和 S 形例程。 本研究有利于推动高性能软体水下机器人的设计与开发，所采用的仿生机制和驱动方法可以推广到其他各种柔性装置和软体机器人。