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

本文介绍了利用柔性鳍的行波运动对水下推进机构推进特性的实验研究。在实验中，柔性鳍附着在水下航行器的侧面，柔性板的行波运动由凸轮和从动件机构产生。研究了柔性鳍波动的波数和频率对推进特性的影响。因此，本研究取得了以下主要成果。(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前后运动。(2)水下推进机构利用高波数的行波运动在水中实现平稳运动。另一方面，推进力随着波数的增加而变小。(3)推进力和游泳速度随着行波运动频率的增加而增加。此外，推进力和游泳速度的波动随着行波运动频率的增加而增加。(4)水下推进机构在波数为1.0左右时获得最大游动速度。(5)推进力和游泳速度随无量纲频率的增加而减小，游泳速度的波动取恒定值。(6)为了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，以抑制振动并跟踪期望运动。

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.