Chaotic Anti-Control Research In Thruster System Of Ocean Reconnaissance Robot

This subject researched the chaotic anti-control problem in thruster system of ocean reconnaissance robot, improved the anti-control method of chaos, and proposed a pre-research scheme of the application in thruster system.Thruster system of ocean reconnaissance robot is a typical multi-variable nonlinear time-varying system which dynamic characteristic is necessarily involves chaos field if further study. At present, the study of chaotic phenomena on electrical machinery system is still at the initial stage, no matter domestic or abroad, and the study of chaotic motion in thruster system of ocean reconnaissance robot is facing enormous difficulties. How to applied chaos science to thruster motor of robot system involves two issues, that is, when chaos is useful need an anti-control of chaos, when it harmful need chaos control. Thruster system chaotifying is a new topic that has the challenging and interdisciplinary nature, the study is of important theoretical and practical engineering value. Using chaotic anti-control to improve anti-detection ability of thruster system of ocean reconnaissance robot was researched in the theses; the main study contents are summarized as follows:Firstly, the wavelet phase space reconstruction of chaotic attractors is used to judge whether chaos happened or not in thruster system, it is primary problem to study chaotic anti-control. The real-time noise and chaotic signals of thruster system have essentially different when ocean reconnaissance robot running in deep sea. To solve information redundancy problem of the existing time series phase space reconstruction method, this article introduced the wavelet transform to phase-space reconstruction. The simulation results show that: wavelet phase space reconstruction method is effective way to estimate chaos, that could accurate reconstruct the original features of chaotic systems, reconstructed periodic characteristics, multi-periodic characteristics and quasi-periodic characteristics of the original system.Secondly, differential geometry theory has been introduced to permanent magnet thruster motor for solving the problem of nonlinear object difficult to control. This theses completed multiple-input multiple-output non-interactive control design of the permanent magnet thruster motor using state coordinates transformation and state feedback transform. The parameter uncertainty problem of permanent magnet thruster motor system is studied with adaptive feedback linearization theory on this basis. The simulation results show that the differential geometry theory is used to thruster motor can convert nonlinear system of permanent magnet thruster motor into linear system under the conditions of not lose any useful information, and that applied nonlinear control based on differential geometry theory to areas of motor control has enriched research means.Thirdly, because of the nonlinear impact of power electronic controller and the influence on system stability of whole thruster system can not be ignored, this theses have made equivalent transformation to the mathematical model of ocean reconnaissance robot system including the permanent magnet brushless DC motor system, propeller and robot. The conditions can be carried out exact linearization are analyzed applying differential geometry theory. Based on above study, this theses pointed out the non-directly relevance between translational equation and propulsion plant of ocean reconnaissance robot, and proposed the chaotic anti-control method for ocean reconnaissance robot thruster device using time-delay state feedback exact linearization technology according to this conclusion. The results showed that the shape of chaotic attractor and chaotic state of thruster plant can be changed by adjusting the parameters of the anti-controller under the condition of ensuring the normal running of the robot.Fourthly, a chaotic anti-control method of time-delay state feedback pulse control based on the time-delay state feedback exact linearization method was proposed to solve the characteristic of the low-pass filter of thruster plant. Based on the above research, a technical scheme which makes the unique voiceprint characteristic chaotification of thruster motor was proposed by changing the parameters of chaotic controller and the rectifier device. The input signal of the thruster motor changed and caused its phase current chaotic. So the electromagnetic torque chaos lead to the shaft vibration changed, and the noise of propeller unique voiceprint characteristic is changed also. That is, the noise from its unique characteristic changed into a chaotic state at all times. As a result, achieve the purpose of confusing the enemy. This study made an attempt for chaotic anti-control application in the ocean reconnaissance robot. Finally, the proposed control strategy was verified by related experiment with a prototype and test platform developed by research group. The results shown that the computer simulation and experimental is basically consistent with theoretical expectations.