Design and attitude control of a novel robotic jellyfish capable of 3D motion

Yu, Junzhi; Li, Xiangbin; Pang, Lei; Wu, Zhengxing

Sci China Inf Sci, 2019, 62(9): 194201

Aquatic creatures such as fish, cetaceans, and jellyfish could inspire innovative designs to improve the ways that manmade systems operate in and interact with aquatic environments. Jellyfish in nature use jet propulsion to move through the water, which have been proven to be one of the most energetically efficient swimmers on the planet. Researchers are making an integrated effort to develop smart actuators to abricate various robotic jellyfish, such as shape memory alloys (SMA), ionic polymer metal composites (IPMC), and dielectric elastomer actuator. Most of existing robotic jellyfish cannot freely adjust their three-axis attitude, which has an adverse effect on free-swimming propulsion and plausible applications. We investigate how to design and control a bio-inspired motor-driven robotic jellyfish capable of three-dimensional (3D) motion. The main contributions of this work are twofold. First, a novel 3D barycenter adjustment mechanism is implemented, allowing flexible regulation of the robot's barycenter. Second, the proposal of the reinforcement learning based attitude control method makes autonomous attitude regulation possible. In comparison with most of the other robotic jellyfish, the built robot displays a high order of structure flexibility and yaw maneuverability. Therefore, this self-propelled robotic jellyfish with 3D motion has great implications for bio-inspired design of jet propulsion system with great agility.

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