A Novel Robot Fish With Wire-Driven Active Body and Compliant Tail

In the past two decades, a large number of robot fishes have been built, though their performances are still far inferior compared with that of the real fish. One of the key reasons is the design. This paper presents a novel robot fish. The key innovation is the combination of an active wire-driven body with a soft compliant tail to accomplish undulatory swimming (i.e., flapping in “S” motion). First, the design is presented. Second, the design and analysis model is given. In particular, it is shown that the compliant tail can be modeled through the proposed multipseudolink model. Then, a prototype and experimental results are presented. The experiment results demonstrate that the kinematics of the robot fish can be predicted by the presented model with reasonable errors. Moreover, it has several advantages; simple in structure, easy to control, capable of high-speed swimming (the maximum speed is 2.15 body lengths/s), and good maneuverability (the average turning speed is 63°/s). Most importantly, it is highly efficient; the swimming performance of the robot fish is close to that of a real fish.