Chaos Phenomena Research Of Thruster Motor In Deepwater Robot

In this thesis, the occurrence, prediction and control of chaotic phenomenon for a brushless thrustermotor in deepwater robot have been studied, through chaotic theories some results with special theory meaning and practical value have been got. They cover the following several major parts:In the first part, the phase space of the reconstituted brushless motor system, the improved Lyapunov exponents method for chaos prediction, the proposed global largest Lyapunov exponents method and global algorithm with track vectors have been achieved and applied in the brushless thruster system for diagnosing and predicting chaos. And the disadvantages of the single phase-space method, such as, the inaccuracy, no integrity and wrong prediction information have been overcome using the global largest Lyapunov exponents method. The whole variation of chaos for the deepwater robot brushless thruster motor system from the static state to pseudo-chaos till real chaos can be clearly and roundly depicted without missing the important information. And the concept of the pseudo-chaos is introduced to solve the incorrect depiction of the system operating state.In the second part, chaos attractor characteristics have been analyzed by wavelet analysis, power spectra and analysis poincare map. The basin of attraction diversity contained in similar disorder attractors is shown in the first time; furthermore, the heteroclinic orbit of chaos basin attraction and heteroclinic orbit's anchor points have also been analyzed and depicted, which settles the bases for chaos controlling, synchronization of chaos as well as anti-control of chaos from inner microcosmic point of view.In the third part, the self-adaptive control method of chaotic system is adopted to design a chaos self-adaptive controller, which can effectively restrain the chaotic phenomenon, break away and eliminate the chaos eventually. The technique of chaos self-adaptive control possesses some characteristics, such as, the simpleness, reliability, and convenient implementation in software and hardware for engineering applications.In the fourth part, the chaos prediction, control method and optimization have been employed in the practical cases, and a novel concept for brushless thruster motor in deepwater robot based on the chaos theory to avoid and retrain chaos generation has been presented. Moreover, the proposed motor is designed and shown that no instability and chaotic actions occur under meeting the technical requirements.In the fifth part, state equation from the dynamics model of the multi-phase brushless thruster system has been established and the dynamic characteristics has been analyzed by the numerical simulation method Moreover, results have been verified by the experiments. Furthermore, the "butterfly effect" of chaos attraction gene during the chaos motion has been clearly presented in this thesis.In the sixth part, from theory and experiment test, the torque surge as well as the chaos phenomenon generation reasons in deepwater robot thruster are discussed.