微型潛艇氣動(dòng)推進(jìn)系統(tǒng)的
設(shè)計(jì)與仿真
大摘要
微小型潛艇的應(yīng)用意義重大，但現(xiàn)有的推進(jìn)方式和供氧方式存在著結(jié)構(gòu)復(fù)雜、質(zhì)量大、經(jīng)濟(jì)性差、污染嚴(yán)重等各種各樣的問題。本文提出一種全新的構(gòu)想，即利用復(fù)合材料高壓氣瓶和氣動(dòng)馬達(dá)等元件組合而成的氣動(dòng)系統(tǒng)為該種潛艇提供推進(jìn)動(dòng)力，同時(shí)氣動(dòng)馬達(dá)的排氣也能為艙室提供供人體呼吸的氧氣，實(shí)現(xiàn)推進(jìn)和供氧的雙重目標(biāo)，使微型潛艇更加經(jīng)濟(jì)、環(huán)保、安全、可靠。并借助計(jì)算機(jī)仿真技術(shù)對(duì)設(shè)計(jì)方案進(jìn)行計(jì)算和模擬，計(jì)算機(jī)仿真是利用系統(tǒng)的數(shù)學(xué)模型在計(jì)算機(jī)上進(jìn)行的實(shí)驗(yàn)，它的特點(diǎn)是投資少、無風(fēng)險(xiǎn)、見效快以及不受實(shí)驗(yàn)條件的限制等。
因本文所涉及的學(xué)科較多，主要包括熱力學(xué)、氣體動(dòng)力學(xué)、機(jī)械、控制、潛艇原理、仿真技術(shù)等學(xué)科的知識(shí)，故本文選擇了先進(jìn)的多學(xué)科領(lǐng)域系統(tǒng)建模與仿真軟件SimulationX以及新興的Modelica語言作為平臺(tái)，設(shè)計(jì)并搭建了基于某微型旅游潛艇的氣動(dòng)推進(jìn)系統(tǒng)模型。
該氣動(dòng)推進(jìn)系統(tǒng)模型分為船槳系統(tǒng)子模型、減速器子模型、氣動(dòng)馬達(dá)子模型、氣動(dòng)動(dòng)力系統(tǒng)子模型、控制系統(tǒng)子模型以及三維模型子模型。建模和仿真的具體步驟包括：
（1） 利用進(jìn)角系數(shù)法建立螺旋槳子模型以防止仿真中出現(xiàn)的中斷或其他異常。
（2） 鑒于艇體阻力計(jì)算和潛艇運(yùn)動(dòng)的復(fù)雜性，對(duì)阻力和運(yùn)動(dòng)方程做了簡化處理，將艇體表面的摩擦阻力作為計(jì)算總阻力的依據(jù)，并將復(fù)雜的潛艇六自由度運(yùn)動(dòng)簡化為X、Y、Z三個(gè)方向的直線運(yùn)動(dòng)。
（3） 利用實(shí)驗(yàn)?zāi)Ｐ图摧敵鎏匦詠肀磉_(dá)氣動(dòng)馬達(dá)模型，不僅更接近實(shí)際情況，而且能有效縮短仿真計(jì)算時(shí)間。通過不同功率的氣動(dòng)馬達(dá)與不同減速比的減速器以及船槳系統(tǒng)模型的匹配仿真，選擇最為合適的氣動(dòng)馬達(dá)和減速比。
（4） 根據(jù)所選馬達(dá)的耗氣量與潛艇續(xù)航時(shí)間計(jì)算滿足要求的高壓氣瓶的工作壓力和容積?？紤]到高壓氣體在減壓過程中，氣體與閥的摩擦損耗以及大幅溫降導(dǎo)致的能量損失，在動(dòng)力系統(tǒng)中引入高壓容積減壓方式和熱交換器，以提高氣動(dòng)系統(tǒng)的效率，增加潛艇的續(xù)航時(shí)間。
（5） 為了實(shí)現(xiàn)對(duì)微潛運(yùn)動(dòng)的控制，利用PID控制器調(diào)節(jié)流量閥的開口大小，繼而調(diào)整氣動(dòng)馬達(dá)的輸出轉(zhuǎn)矩和轉(zhuǎn)數(shù)，從而控制潛艇在X、Y、Z三個(gè)方向的直線運(yùn)動(dòng)。通過經(jīng)驗(yàn)法調(diào)整PID控制器的3個(gè)參數(shù)，獲得了較為理想的位移響應(yīng)曲線。通過合成微潛在X、Y、Z三個(gè)方向的位移，得到潛艇在三維空間中的運(yùn)動(dòng)。
（6） 最后，利用軟件SimulationX中的MBS模塊搭建潛艇的三維示意視圖，將位移的仿真計(jì)算結(jié)果賦給三維模型，在仿真計(jì)算的過程中，可觀察其三維運(yùn)動(dòng)軌跡，令仿真過程更加形象、生動(dòng)。


Abstract
The application of mini-submarine is significant whereas there’re various problems in now available propulsive methods such as complicated structure, massive quality, low economical efficiency, severe pollution; etc. A bran-new idea has been conceived namely pneumatic propulsion system which includes high-pressure air bottle and air motor that can provide not only the propulsion power but also the oxygen supply for compartments. It’s a solution to dual targets that makes mini-sub more economical, more environment friendly, safer and more reliable. Design Scheme has been calculated and simulated with the help of computer simulation which is an experiment based on computer with mathematical model of system. It needs small investment and with no risk, fast effective and suffers no limitation of experiment condition.
The theme involves several disciplines, e.g., thermodynamics, pneumodynamics, machinery, control, principle of submarine, simulation technique, etc. Therefore, an advanced interdisciplinary modeling and simulation software SimulationX and a newly rising langue Modelica were adopted for the terrace. Pneumatic propulsion system based on a mini tourism submarine was constructed.
Propulsion system model consists of hull resistance submodel, propeller submodel, reducer submodel, air motor submodel, pneumatic system submodel and control system submodel and 3D submodel. Steps of modeling and simulation in detail include:
(1) Angular coefficient method was adopted to establish propeller submodel in order to avoid suspension and other unusual situations in the process of simulation.
(2) Due to the complexity of hull resistance calculation and submarine motion, the total resistance of the submarine was calculated according to frictional drag of the hull, further, the resistance and equation of motion in 6 DOF were simplified to 3 displacements in X、Y、Z directions.
(3) Experimental model, or output characteristics were applied to demonstrate air motor which can not only approximate reality but also shorten simulation duration effectively.Through matching simulation among different air motors and different reduction ratios and submarine-propeller, selected the most appropriate air motor and reduction ratio.
(4) Working pressure and volume of the required high-pressure air bottle were calculated according to air consumption of the selected air motor and the cruise duration of submarine. Considering the friction loss between air and valve and the energy loss caused by sharp temperature decline in process of decompression of high-pressure air, brought in volume-decompression method and heat exchanger to the propulsion system in order to improve efficiency of the pneumatic system similarly prolong cruise duration of the submarine.
(5) In order to realize the control of submarine motion, regulating flow valve stroking with PID c..