A Novel Bionic Robot Fish Using PVC Gel Actuators

Robot fish has become a popular topic of research in the past decades. Developing the actuation of robot fish has become a key point of research. In this paper, we proposed a novel actuation mechanism based on new soft actuators called PVC gel actuators. The PVC gel actuators can simulate the contraction of fish muscles under the switch of voltage, and the overall mechanism can realize the movement of swinging to both sides. The prototype system was designed, fabricated, assembled and tested, which showed good actuation performance on land and underwater. The swinging experiment showed the fishtail was able to move and generate force underwater. Resonant frequencies are different between onshore (2 Hz) and underwater (1 Hz). The resonance increases the swing of the fishtail and promotes underwater propulsion. Cruising and turning motion modes were also tested. The speed of fish cruising could reach 0.12 m/s (0.2 BL/s), which demonstrated the potential of this kind of actuation.