水下滑翔機之動態模擬與實驗

Underwater Glider Dynamic Simulation and Model Test

蕭左政(Tso-Cheng Hsiao)

指導教授 ： 謝傳璋

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.00514

摘要

本研究分為水下滑翔機的數值模擬與水槽模型試驗兩部份。水下滑翔機的運動原理，是利用機內的「浮力引擎」，控制機內一水艙的進�排水量，即改變機身重量，使機體發生浮沉運動的同時，自行滑翔前進。
本文的數值模擬是針對一選定的機型，探討在不同的重心和浮心位置，重力與浮力差、及不同的初始條件下，以Matlab軟體編寫程式，使用Runge-Kutta法積分，求解機體運動的聯立微分方程組。計算該機體重心的運動軌跡，滑行速度及滑行姿態。
為了程式使用者方便，並建立了一套GUI人性化介面，透過此介面，能更方便地修改計算的條件。本機型的流體動力係數，是根據DATACOM資料庫中的經驗公式推估。
水槽實驗部份，首先是製作圓柱型機體，再配以矩形薄板機翼及尾部的穩定翼。在機體首部設置「氣壓式」浮力引擎，其原理為利用一灌有高壓氣體（或液態氣體）的鋼瓶。搭配數位式電磁閥門，以控制高壓氣體在導管內的流向，使彈性氣囊充氣（排氣），並藉著彈性氣囊的膨脹（收縮），將水室內的水排出（吸入），此時機體因浮力（重量）改變力而上浮（下沉）。夲試驗在台大工科海洋系水槽中進行。水槽內裝設兩部水中CCD攝影機，拍攝機體的滑翔影像，配合預先繪畫在槽壁的座標格線，判讀其軌跡及姿態。試驗與數值模擬結果：一週期的水平航程分別為9m與10.2m，深度分別為3m與3.2m，下沉時之俯仰角分別為23.75度與23.3度，上浮之俯仰角分別為34.06度與33.04度。

關鍵字

水下滑翔機 ； 運動軌跡 ； 水槽試驗 ； 浮力引擎

並列摘要

The numerical simulation and model test of the dynamic motion of an Underwater Glider were studied in the paper.
The operational principle of the Underwater Gliders is to use the so called Buoyancy Engine, to control inflow and outflow of the water volume inside its water chamber, i.e. to change the buoyancy (or weight )of the glider, so that the glider would move forward during its up-lift and down-sink motion.
The numerical simulations were carried by O.D.E. solver in Matlab. Base on the Runge-Kutta time integration this solver calculate the dynamic motion of the glider, so that the gliding velocity, angle of attack and the trajectory of the glider can be obtained simultaneously. A GUI (Graphical User Interfaces) program is also written so that the design parameters and the initial conditions of the simulation can be easily changed for the program users.
In this simulation, empirical hydrodynamic coefficients were estimated according to the Datacom database.
For the model test, a P.V.C cylindrical glider body with rectangular thin wing was made firstly. A pressure type buoyancy engine was designed inside the glider body. It consists of a steel bottle with highly compressed air inside, electromagnetic valves and piping system. The working principle of this buoyancy engine is to use the valves to control the inflow and outflow of the compressed air in the elastic bladder inside the water chamber. So that the glider would perform lift-sink motion due to the effect of buoyancy force changed.
The test is conducted in the water tank in the Department of Engineering Science and Ocean Engineering of NTU. Two underwater CCD cameras were use to record the image of the glider motion, with the help of the coordinate line printed on the tank wall, its trajectory can be obtained.
The test results are:
The horizontal range of a cycle is 9m, the depth of a cycle is 3m, the pitch angle (when sinking) is 23.75 degrees, the pitch angle (when lifting) is 34.06 degrees.
The numerical simulations results are :
The horizontal range of a cycle is 10.2m, the depth of a cycle is 3.2m, the pitch angle (when sinking) is 23.3 degrees, the pitch angle (when lifting) is 33.04 degrees.

並列關鍵字

Underwater Glider ； Motion trajectory ； Water tank test ； Buoyancy engine

參考文獻

[6]Liu Yu-Jui劉于睿,”水下滑翔機之動態模擬”國立台灣大學,2007

[4] Scripps Institution of Oceanography---spray

[5] Applied Physics Laboratory of University of Washington---seaglider

and Coordination of Underwater Gliders ", Princeton University,Proc. 41st IEEE Conf.

Unmanned Untethered Submersible Technology (UUST), August 2003