模块化仿生波动推进器设计与控制研究

Design and Control of Modular Bionic Undulating Fin Propeller

摘要:

仿生波动推进方式具有机动性好、适应性强、环境友好等优势，在水下机器人应用中具有广阔前景。为提高仿生波动鳍推进速度、减小质量与体积、提高可靠性，提出了一种基于凸轮驱动的模块化仿生波动推进器，基于自抗扰控制方法实现仿生波动鳍的频率连续精确控制。针对波动鳍仿生构型进行设计，对正弦波发生机构进行理论计算与运动仿真，推导了凸轮机构瞬时效率公式，平均效率最高可达83.6%。以波动鳍输出频率为控制目标，建立了波动鳍控制模型。理论推导与流体仿真结果表明，在定常频率下波动鳍内部特性与外部负载均呈非线性时变效应。设计了线性自抗扰波频控制器，基于STM32单片机搭建了波动鳍测控实验系统。实验结果表明，在低频与高频下波动鳍均能准确跟踪期望频率，响应曲线平缓连续且无超调，稳态波动误差小于2.3%。当频率为3Hz时，自抗扰控制器与PID控制器输出波动误差分别为6.3%和2.1%，自抗扰控制精度提高66.7%。研究结果表明，该模块化仿生波动推进器控制精度高、集成度好，可任意数量配置到仿生水下机器人上，具有较好的应用价值。

Abstract:

The bionic undulating propulsion method has the advantages of good manoeuvrability, strong adaptability, and environmental compatibility, which shows broad prospects in the application of underwater robots. To enhance the propulsion speed, reduce the weight and volume, and improve the reliability of the bionic undulating fin, a modular bionic undulating propeller based on cam mechanism was proposed. Active disturbance rejection control (ADRC) method was used to achieve the continuous accurate control of wave frequency. The structure of the undulating fin was designed. The mathematical model of the sinusoidal wave generating mechanism was established. The instantaneous efficiency formula of the cam mechanism was derived, resulting in an average efficiency of 83.6%. The motion simulation was carried out and the result proved the feasibility and the correctness of the cam parameters calculation. Taking the output frequency as the control target, the control model of the undulating fin was established. The theoretical derivation and computational fluid dynamics simulation analysis showed that both the internal characteristics and the external loads of the undulating fin suffered from nonlinear time-varying effects at constant frequency. To overcome the negative effect of internal and external disturbances, the linear active disturbance rejection controller was designed for frequency control. Based on STM32 single chip microcomputer, the experimental measurement and control system of the undulating fin was realized. The experimental results showed that the undulating fin could accurately track the expected frequency at both low and high frequencies. The response curve was smooth and continuous without overshoot, and the steady-state fluctuation error was less than 2.3%. When the frequency was 3Hz, the output fluctuation errors of the active disturbance rejection controller and the proportion integration differentiation controller were 6.3% and 2.1%, respectively, and the control accuracy was improved by 66.7%. The research results showed that the modular biomimetic undulating fin propeller had satisfactory control precision and good integration. As it can be configured to biomimetic underwater vehicles in any numbers, the modular undulating fin had good application value.