Motion Control and Propulsion Performance of Underwater Propulsion System by Using Traveling Wave Motion of Flexible Fins

本文利用柔性鳍的行波运动对水下推进机构的推进特性进行了实验研究。在实验中，将柔性鳍安装在水下航行器的侧面，通过凸轮从动件机构产生柔性板的行波运动。研究了柔性鳍摆动运动的波数和频率对推进特性的影响。研究结果表明：(1)通过改变柔性鳍的行波运动方向，水下推进机构可以实现正反向运动。(2)利用高波数的行波运动，水下推进机构可以在水中实现平稳运动。另一方面，随着波数的增加，推进力变小。(3)行波运动的频率越高，推进力和游泳速度越大。(4)水下推进机构在波数为1.0时达到最大游速。(5)推进力和游速随无因次频率的增加而减小，游速波动趋于恒定。(6)为实现柔性鳍的行波运动，提出并设计了输出反馈滑模控制器来抑制振动，跟踪期望运动。

This report presents an experimental study of propulsion characteristics of an underwater propulsion mechanism by using traveling-wave motion of flexible fins. In the experiment, the flexible fins were attached at the side of an underwater vehicle, and the traveling-wave motion of the flexible plate was generated by a cam and follower mechanism. The effect of the wave number and frequency of the waving motion of the flexible fin on the propulsion characteristics was examined. As a result, following major things were obtained in this study.(1) The underwater propulsion mechanism can take both forward and backward motion by changing the direction of the traveling wave motion of the flexible fins.(2) The underwater propulsion mechanism can take smooth movement in water by the traveling wave motion with high wave number. On the other hand, the propulsion force becomes smaller with increasing wave number.(3) Propulsion force and swimming speed increase with increasing frequency of the traveling wave motion. Moreover, fluctuation of the propulsion force and swimming speed increase with increasing frequency of the traveling wave motion.(4) The underwater propulsion mechanism takes maximum swimming speed when the wave number is around 1.0.(5) The propulsion force and swimming speed decrease with increasing non-dimensional frequency, and fluctuation of the swimming speed takes constant value.(6) To realize the traveling-wave motion of flexible fins, the output feedback sliding mode controller to suppress the vibration and track the desired motion is presented and designed.