Research On Fault Diagnosis And Fault Tolerant Control Of AUV Propulsion System For Autonomous Underwater Vehicles

Autonomous Underwater Vehicle(AUV)is widely used in complex marine environments and performs tasks such as geological exploration,equipment maintenance,and oil and gas development.However,in the process of autonomous underwater vehicle performing tasks,due to the uncertainty of the environment,once a failure,it will cause irreparable losses,so the reliability of its system is particularly important.This thesis takes the self-developed "Sea Exploration Type I" AUV as the research object,and focuses on the problem of autonomous underwater vehicle thrusters being prone to faults and unable to complete preset tasks.A new method for AUV thruster fault diagnosis and fault-tolerant control is studied,with the main research content as follows:First of all,the domestic and foreign research status and development trends of AUV fault diagnosis and fault-tolerant control were analyzed,and the overall solution design,structural design,key hardware module selection and control system modeling of the "Sea Exploration Type I" AUV were introduced in detail.Then,in response to the problem of autonomous underwater vehicle prone to thruster failures in complex environments,a new AUV thruster fault diagnosis method based on attitude data fusion and particle swarm optimization(PSO)optimized support vector machine(SVM)is proposed.The method mainly includes three parts: data preprocessing,feature extraction,and fault diagnosis.Firstly,Using the set empirical mode decomposition algorithm(EEMD)to decompose the intrinsic mode components(IMF)containing the main fault feature information in the attitude data;Then,a feature extraction method combining sample entropy(SE)and root mean square value is used to form fault feature vectors for the decomposed components;Finally,the fault feature vectors were input into the PSO-SVM model for fault diagnosis,The experimental results demonstrate the effectiveness of the new method for AUV thruster fault diagnosis proposed in this thesis.Secondly,in response to the failure of the autonomous underwater vehicle propeller to fail and to complete the preset task,a new method of tolerance control control control of autonomous underwater vehicle distributed based on thrust is proposed.This article’s research on the tolerance control of the pushing device is based on AUV’s underwater three-dimensional path tracking: In the AUV 3D path tracking design,first designed a improved anti-slide model track tracking controller,which uses fuzzy control to effectively inhibit the effectively suppress Reverse slide sliding mode control the problem of shaking the vibration,combined with Lyapunov stability,proves the gradual stability of the system;then,according to the thrust loss of the pusher,adjust the power matrix and the loss of the fault propeller losses Compensation for thrust;Finally,the AUV 3D road tracking fault-tolerant control control simulation experiments verified the effectiveness of the new method of autonomous underwater vehicle propelled instruments proposed in this thesis.Finally,the underwater three-dimensional path tracking experiment and result analysis of the "Sea Exploration Type I" AUV were carried out,and the AUV thruster fault diagnosis experiment was conducted based on the attitude data obtained from the experiment.The experimental results demonstrate the effectiveness and feasibility of the proposed new method for diagnosing thruster faults in autonomous underwater vehicle.