Study on Stabilization of Undermater Robot with Mechanical Pectoral Fins in Water Currents

本研究内容包括：（1）胸鳍运动的实验分析;（2）胸鳍运动的水动力学模型;（3）两侧装有胸鳍运动装置的机器鱼的机动试验;（4）机器鱼的导引与控制，特别是在水流中的悬停性能;（5）柔性鳍对水动力特性影响的数值模拟。主要结论如下：（1）对黑鲈胸鳍运动的观测表明，胸鳍的顺桨运动和前后运动共同作用，产生了鱼类的前进、后退、盘旋和转向运动。(2)考虑粘性影响的非定常涡格法可以较好地表示具有顺桨运动和超前-滞后运动的胸鳍模型在两种运动之间的相位差范围内的非定常力。(3)由鱼体模型和一对胸鳍运动机构组成的鱼机器人不仅可以前后游动和原地转弯，还可以横向游动。(4)模糊控制的使用使带有一对胸鳍运动装置的机器鱼在水流中按预定的路线游动并围绕指定的点悬停。(5)与刚性鳍相比，柔性鳍可以提高螺旋桨的效率。

This study deals with (I) experimental analysis of pectoral fin motion, (2) the hydrodynamic model for pectoral fin motion, (3) maneuver test of a fish robot equipped with a pair of apparatus of pectoral fin motion on both sides , (4) guidance and control of the fish robot, in particular, the hovering performance in water currents, and (5) numerical simulation of effect of a flexible fin on its hydrodynamic characteristics. The conclusions are as follows ;(1) Observation of pectoral fin motion of Black Bass revealed that the combination of feathering motion and lead-lag motion of a pair of pectoral fins generates the fish motion of advancing, backward swimming, hovering and turning.(2) The unsteady vortex-lattice method including the effect of viscosity can express fairly well the unsteady forces acting on a pectoral fin model having feathering and lead-lag motions in a range of the phase difference between both motions where it exerts thrust force.(3) The fish robot consisting of fish body model and a pair of apparatus of pectoral fin motion can not only swim forward and backward and turn in the same position, but also swim in the lateral direction.(4) The use of fuzzy control enables the fish robot with a pair of the apparatus of the pectoral fin motion swim on a pre-arranged course and hover around an appointed point in a water current.(5) The flexible fin makes it possible to increase the propeller efficiency compared with the rigid fin.