Optimization of Three-Degree-of-Freedom Biomimetic Pectoral Fin Propulsion Law

doi:10.1007/s12204-024-2579-5

Abstract

Abstract: To optimize the movement of the three-degree-of-freedom (3-DOF) pectoral fins, a 3-DOF model of the dolphin-like pectoral fins was established, and the effects of different parameters of the pectoral fins on their propelling performance were simulated using computational fluid dynamics (CFD) technology. Using CFD simulation data as a training set and a multi-layer perceptron (MLP) neural network as a prediction model, the average thrust and lift of the pectoral fin motion under different motion cycles, rowing amplitudes, flapping amplitudes, and feathering amplitudes were predicted and modeled. A multi-objective genetic algorithm was used to obtain the optimal parameter values for maximum thrust and minimum absolute lift, and the optimal motion law for 3-DOF motion was brought. The results showed that the optimal propulsion performance was achieved at a period of 1 s, a rowing amplitude of 36 ◦ , a flapping amplitude of 18 ◦ , and a feathering amplitude of 56 ◦ . Finally, the force and displacement of the robotic fish were collected through indoor pool experiments and compared with the simulation results, indicating that the simulation results are of considerable reliability. The research results have specific guiding significance for the design of the pectoral fins of biomimetic robotic fish.

Key words: biomimetic pectoral fins, law of motion, computational fluid dynamics (CFD), multi-layer perceptron (MLP), finite volume method

摘要： 针对三自由度胸鳍运动规律优化问题，建立了仿河豚胸鳍的三自由度胸鳍模型。采用计算流体力学（CFD）技术，模拟了胸鳍不同参数对其推进性能的影响。以CFD模拟计算数据为训练集，采用多层感知器（MLP）神经网路建立了预测模型。针对胸鳍不同运动周期、前后拍翼幅值、上下拍翼幅值和摇翼运动幅值下的胸鳍运动平均推力和平均升力，进行了预测建模；采用多目标遗传算法获得了推力最大和升力绝对值最小时的最优参数值，得到了三自由度运动最优运动规律。结果表明：在周期为1 s、前后拍翼幅值为36°、上下拍翼幅值为18°和摇翼幅值为56°时，获得最佳推进性能。最后，通过室内水池实验采集了机器鱼受力和位移数据，并与仿真结果进行了比较，验证了仿真结果具有相当的可靠性。研究结果对仿生机器鱼胸鳍的设计具有一定的指导意义。

关键词: 仿生胸鳍，运动规律，计算流体力学，多层感知器，有限体积法

CLC Number:

TP242

Li Bin, Li Zonggang, Li Haoyu, Du Yajiang. Optimization of Three-Degree-of-Freedom Biomimetic Pectoral Fin Propulsion Law[J]. J Shanghai Jiaotong Univ Sci, 2026, 31(1): 195-208.

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