Design And Simulation Of Pneumatic Propulsion System On Minisub

The application of mini-submarine is significant whereas there're various problems in now available propulsive methods. A bran-new idea has been conceived -Pneumatic propulsion system includes high-pressure air bottle and air motor which 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. Computer simulation 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, thereby, 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. Due to the complexity of hull resistance calculation and submarine motion, the resistance and equation of motion were simplified. 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. 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.Regulating flow valve stroking with PID controller as to regulate the air motor output and control submarine motion afterwards. Proper displacement response curves were obtained through adjusting the PID parameters by the empirical approach. The motion in 3D space was manifested by synthesizing 3 displacement in X,Y,Z directions. MBS module was utilized to construct 3D view of the submarine and the displacement outcomes were endowed to the 3D view. It made 3D movement locus can be observed through the whole calculation process which would be more vivid and more picturesque.