Research On Control Strategy Of Motion And Integrated Roll Stabilization For Near Surface AUV

Since modern times,the studies of the sea and the degree of the marine defense are increasing.As an important component of marine high-tech research results,autonomous underwater vehicles(AUV,Autonomous underwater vehicle)are of great value in military and other fields.Because of the complex and changeable working environment,the motion control of AUV has become a very valuable research topic.Based on sliding mode control theory,Lyapunov stability theory and intelligent control theory,combined with the underactuated AUV motion near the surface,this paper makes an in-depth research of underactuated AUV horizontal plane trajectory tracking control,thus it can deal with the problem of nonholonomic constraints,model coupling,nonlinear characteristics,current disturbance,and tracking accuracy.Based on the terminal sliding mode control method for underactuated AUV trajectory tracking control,the research is of significance to achieve good tracking effect on the control system.In addition,in order to solve the problem of the near surface AUV navigation generated when pitching and rolling,the research analyzes the dynamic resistance model of AUV,starts from a non minimum phase characteristic of the rudder with the model of anti-roll system.From the rudder stabilizer system with non-minimum phase characteristic model,adaptive control method,feedback linearization method,the nonlinear sliding mode control method are combined and used to study the new damping composite of AUV energy optimization control strategy.The above strategy is designed to improve the roll stabilization efficiency of AUV and the dynamic quality of AUV motion system.Specific research work is as follows:1.The ground coordinate system and hull coordinate system of AUV are defined,and the conversion from ground coordinate system to ship coordinate system is completed.The kinematics model and dynamics model of the underactuated AUV are established,and the effects of nonlinearity and coupling,underactuated and external disturbances on the controller are analyzed.Based on the optimization of the parameters,the longitudinal motion model of the AUV in the vertical plane is established.And the pitching angle and heave displacement being taken as constraints,the analysis of wave force and moment and its resistance in near surface AUV is carried out.2.In order to improve the accuracy and robustness of the trajectory tracking of underactuated AUV,a trajectory tracking controller based on nonlinear terminal sliding mode is designed.The purpose of the proposed control scheme is to ensure the tracking accuracy,and effectively improve the anti-jamming performance of the AUV plane trajectory tracking.According to two closed loops of position and posture,each individual trajectory tracking controller is designed.And based on Lyapunov stability theory,the effective stability of the control system is analyzed to ensure the precise horizontal plane control of the AUV under the time-varying disturbance.3.In the engineering background of the AUV in the near surface navigation,in-depth research on the dynamic resistance model for AUV pitching motion is made,and then the dynamic control model of the pitching angle,pitch displacement and driving energy as a comprehensive index is studied.AUV pitching motion is researched considering the dynamic resistance under the influence of the longitudinal rocking suppression strategy.The LQR method,nonlinear adaptive sliding mode method and adaptive fuzzy sliding mode control method are designed to optimize the AUV navigation in the near surface by pitching motion caused by the resistance increase,realize the energy optimized endurance control.4.For the problem that most nonlinear anti-rolling devices do not consider own existence nonlinearity which lead to the low anti roll rate,a non-minimum phase nonlinear AUV model from the rudder to the roll angle of the stabilizer nonlinear conditions is considered to be established,then a method of feedback linearization and nonlinear fuzzy sliding mode control method combining inversion based on the stability theory is proposed,which can effectively control the course and synchronous rolling of the rudder roll control method,so as to improve the stability and robustness of the closed-loop system.In this paper,the stability of the control method is proved by Lyapunov stability theory.The proposed theory which ensures the safe and reliable performance of AUV in near surface motion has important practical value in engineering.