Parametric Study of the Swimming Performance of a Novel Robot Fish With Active Compliant Propulsion Mechanism

This paper presents a novel robot fish propelled by an active and compliant propulsion mechanism. The key innovation of this robot fish is the combination of an active wire-driven mechanism with a soft compliant tail to construct the active compliant propulsion mechanism, which can accomplish multi-modal swimming motions. First, the design method was proposed, the wire-driven mechanism and the compliant tail could be well designed. Second, using this robot fish experimental platform, numerous experiments were conducted to investigate the effect of different controllable parameters on cruising speed, descending speed and turning performance. These parameters include flapping frequency and amplitude of the propulsion mechanism, attack angle of the pectoral fins. A more detailed parametric study was conducted with these significant parameters to study and understand the relationship between swimming performance and various parameters. This process can help to optimize controllable parameters for superior swimming performance. Based on the parametric study, we obtained the best experimental swimming performance under optimized parameters; the maximum speed reached 2.15 BL/s (body length per second), the maximum turning speed is 269°/s the descending speed is 42 cm/s (when attack angle is 60 degree). Compared with existing robot, the new robot fish has several advantages: it is simple in structure, easy to control, and capable of high speed swimming and maneuverable swimming.