Unmanned Surface Vehicle Navigation Control Research Based On Sliding Mode Variable Structure

Over the past few decades,with the horrific events and the wars of the sea and the continuously demand for resources by the the growth of population,the research and application of unmanned surface vehicle(USV)have been developed rapidly.The quality of control methods of unmanned surface vehicle course for the whole course system is crucial.Variable structure control is a nonlinear control method,which has a significant effect on the dealing control problem of nonlinear system objects.However,due to the uncertainty of the system object and external interference,a single variable structure control method has yet to be improved in the control effect of unmanned surface vehicle.This paper focuses on the introduction of other control methods and variable structure control methods to form a composite variable structure control strategy,and its use in the field of unmanned surface vehicle course.The main contents are as follows:With USV as the research object,a method of adaptive backstepping Sliding mode control(SMC)based on system immersion and manifold invariant(I&I)is proposed in the article.then the adaptive super-twisting backstepping sliding mode controller is designed based on backstepping thought and sliding mode control theories.Where,the I&I method is used to design the adaptive disturbance estimation,the additional compensation item is brought into the whole adaptive law and the disturbance estimation error manifold is established,using the designed adaptive law to ensure the invariant and attractive of error manifold,so the convergence of disturbance estimation error can be guaranteed.The simulation results indicate that the designed controller can estimate the external disturbance accurately,the course control of USV is superior to the classical adaptive sliding mode control.A new power reaching law is proposed which can solve the problems in the traditional reaching law of the traditional sliding mode control such as low convergence speed for the course control question of USV.then the new terminal sliding mode controller is designed based on new reaching law thought and terminal sliding mode control theories.The simulation results indicate that the designed new controller can proposed is faster than other reaching laws such as the traditional power reaching law,the exponential reaching law.It also shows a better movement quality of the proposed reaching law.Based on the previous study of the sliding mode control of USVcourse,And continuefurther study about the sliding mode control method works on the track control of the underactuated USV,the surge control law and lateral motion control law are designed based on new reaching law thought and sliding mode control theories.The simulation results show the new designed controller is strongly robust regarding the uncertain parameters and disturbances and can force the USV to track a desired trajectory which is generated by a virtual ship.