Research Of Multifunction Autonomous Underwater Vechile Motion Control

As the autonomous work basis of autonomous underwater vehicle (AUV), motioncontrol is one of the key technologies of AUV. Thus, it is significant in theory and engineeringto research on the motion control. This thesis aims at improving motion control effect,enhancing the intelligence of motion control system and modifying the fault diagnosis andtolerance ability of control software, so that better motion control performance, higherreliability and fitness for complex ocean environment can be acquired.A newly developed AUV which is taken as the research object is equipped with kinds ofdetective sensors and so can do kinds of detective works. Since there are differentrequirements for the motion performance in accordance with different working tasks, themotion control system has to adjust control strategy and control method according to thecharacteristics of different tasks. Meanwhile, the motion control system has to efficientlycomprehend the outer information in order to improve the execution efficiency and controllerperformance. Besides, the system reliability of the AUV needs a motion control system withfault diagnosis and tolerance abilities. And the stability of the motion control algorithmS-plane control algorithm, under-actuated motion control, comprehension technology of theouter information, and fault diagnosis and tolerance of motion control software are reseachedin this dissertation.Aiming at the stability of S-plane motion control method, it is analyzed in two aspects,position control and speed control. Using Lyapunov stability theory and T non-source theory,the stability of the S-plane position controller is proved. And S-plane speed controller isderived based on the position controllet, then the stability of speed controller is analyzed. Theadaptive S-plane control method is proposed by modifying the traditional S-plane control, andit is tested during real sea trial in which the experiments results are acquired.The under-actuated problems of sway and heave motion happen owing to shutting downthe tunnel thrusters while the AUV moves at a high speed, in order to solve these, the ellipsesight ray method and anti-step method are used to construct the under-actuated line path tracking controller, and the line path trackingcontrol is achieved, the ses trial results aregiven. The under-actuated terrain tracking controller is built by using the height data fused inT-S fuzzy method, and the terrain tracking under sea is achieved, the method is tested in seatrial. The under-actuated depth controller based on virtual control varible is built, so that thedepth control of the AUV with excess buoyancy is avhieved, the method is tested insimulation experiments.Researches on two kinds of outer information, comprehension of planning instructionsand acoustic targets, are discussed. The planning instruction comprehension model is builtaccording to the thoughts of Itti vision attention model, and the re-planning is done accordingto the comprehension of planning instruction, so that the expected motion state of planningsystem can be realized in a reasonable way, and the method above is tested in simulationexperiments. The classification and identification of acoustic targets are achieved usingdynamic clustering method with forgotten factor. Besides, the motion information of trackingtargets is filtered by using strong tracking kalman filter to make the information more precise,and the method is tested by target tracking trial in tank.To slove the fault diagnosis and tolerance problems of motion control system software,the motion control system software based on vxWorks OS is divided into system level tasksand normal level tasks formed by several functions. And software fault diagnosis andtolerance is designed from three levels, system level, task level and function level, thus, thereliablity of motion control system software is guaranteed when certain faults happen.