Swaying Wire-driven Robot Fish Design and Prototyping

In this paper, a newly designed robot fish adopting bio-inspired wire-driven mechanism is presented. It can twist its caudal fin to give sway motion, just like most of the fish do when cursing. First, sway motion analysis and computer simulation are conducted. Next, a prototype is built and experiments are carried out to validate the simulation results. It is noted that the robot fish may roll side to side during swimming. To optimize the design, we study the fish with small pectoral fin and mimic its bone structure. The new design adopts a gradual decreasing eyelet spacing along the spine. This helps the swaying concentrated at the rear part of caudal fin. Based on the computer simulation, the new design results in an improved performance.