| Unmanned surface vehicle(USV),as a small surface intelligent device,has the characteristics of small size,low cost,light and convenient,high intelligence,etc.,and has a wide range of application prospects in military and civilian fields.Trajectory tracking is one of the key technologies in the field of USV motion control,which can ensure the smooth execution of USV missions.This paper focuses on the accuracy,stability and robustness of USV track tracking,using Model Predictive Control(MPC),Line Of Sight(LOS)guidance and other methods to carry out the USV track tracking strategy research,the main research work is as follows.(1)In order to To solve the problem of USV maneuvering performance prediction,a parameter identification method based on recursive least squares method has been proposed.Firstly,the maneuvering motion performance of the USV has been analyzed by conducting slew test and Z-shaped test;then,the parameters of the USV response type model have been identified and applied to the actual heading motion process.The experimental results show that the identified parameters have high accuracy and can effectively predict the maneuvering motion of the USV.(2)In order to solve the heading control problem of USV under rudder constraints and external environmental disturbances,a heading prediction control strategy based on the state space model has been proposed.The MPC-based heading controller has been designed based on the USV response type model obtained from the parameter identification.The experimental results show that the MPC strategy has higher accuracy,better anti-interference capability and better robustness than the PID strategy for heading control.(3)In order to solve the problem of tracking error becoming larger due to steering in the unmanned boat track tracking process,an USV track tracking strategy based on the cascade form of adaptive LOS guidance and MPC heading control algorithm has been proposed.In the guidance loop,the adaptive LOS guidance law has been designed by using the adaptive admittance circle strategy to adaptively adjust the admittance circle radius of the track points according to the angle between the track segments;in the control loop,the guidance algorithm has been combined with the heading prediction controller to design the USV track tracking control system.The experimental results show that the adaptive LOS+MPC strategy can effectively reduce the track tracking error,decrease the speed loss,reduce the energy loss,perform the surface task better and have higher application value compared with the traditional LOS+MPC strategy. |
