Trajectory Tracking Control Of Air Cushion Vehicle With Sideslip Angle And Yaw Rate Constraints

In response to the increasingly tense international relations,under the influence of the global epidemic,land resources are increasingly depleted,and the ocean has become a place where various countries must compete for resources.As a high-performance ship,the air cushion vehicle has been applied in both military and civil applications,and has a wide range of application prospects.The hovercraft has extremely high maneuverability and can efficiently perform tasks such as beach landing,cruising,and transportation of personnel and materials.Its unique amphibiousness and the realization of dockless berthing capabilities cannot be achieved by other conventional surface ships.Because the actuator of the hovercraft is different from the traditional surface ship,air propeller and air rudder are installed on the water surface,there is no underwater actuator,and the hull is suspended above the water surface during sailing,and the water resistance is small.If there is not enough centripetal force during the turning process,it is prone to sideslip,roll and may cause dangerous accidents such as ship capsize.Moreover,the hovercraft has a high speed,and it is necessary to steer carefully at high speeds.The pilot must always pay attention to the changes of the hovercraft sailing parameters to avoid possible safety risks such as resistance peaks and safety limits,which greatly increases the physical and mental burden on the pilot.In summary,this paper takes the hovercraft as the research object,considers the safety issues that may occur during the navigation process,restricts the hovercraft and the sideslip angle,and designs the track tracking controller under the premise of ensuring safety to achieve the desired voyage.Trace tracking,mainly in the following aspects:(1)First,analyze the power characteristics and forces of the hovercraft,simplify the sixdegree-of-freedom mathematical model of the hovercraft,and give the four-degree-of-freedom motion mathematical model of the hovercraft including lateral,longitudinal,slewing and heeling.The mathematical model of hydro-pneumatic power and actuator is given.Afterwards,for the chattering problem of sliding mode control,an improved multi-power sliding mode reaching law was designed to ensure that the system can converge quickly far away from the equilibrium point and near the equilibrium point,improve the control accuracy,and significantly weaken the chattering phenomenon.And use the sliding mode approaching law to design the speed and slew rate controller,then design the trajectory tracking controller,use the Lyapunov method to prove its stability,the simulation results verify that the controller can have a certain model uncertainty in the hovercraft The task of speed and slew rate control and trajectory tracking tasks are completed with high accuracy under conditions of stability and unknown disturbances from the outside world.(2)In view of the safety problems that may be caused by the excessive sideslip angle of the hovercraft in the process of high-speed navigation,the sideslip angle should be considered in the process of trajectory tracking control.First,according to the hovercraft kinematics model,the sideslip angle constraint is converted into the constraint on the longitudinal speed at different lateral speeds,and the Log-type barrier Lyapunov function is used to constrain the longitudinal speed error,which can ensure that the longitudinal speed is strictly constrained within the range,So as to ensure that the sideslip angle is also strictly constrained within the safety range,and to ensure the safety of the hovercraft trajectory tracking process.After that,mathematical modeling and analysis were performed on the bow nozzle,and a sideslip angle constraint controller based on the bow nozzle was designed.The sideslip angle was constrained without changing the expected longitudinal speed.The simulation results verified it.Constraint effect,and can guarantee the accuracy of hovercraft trajectory tracking.(3)In view of the safety problems caused by sideslip and excessive slew rate of the hovercraft during navigation,through analyzing the direct navigation performance and slewing performance of the hovercraft,the sideslip angle and slewing angle of the hovercraft at different speeds are obtained.The safety limit curve of the hovercraft side slip angle and slew rate is designed,and then the safety limit area is compressed as the trigger point of safety control.Combined with the auxiliary dynamic system,a track tracking controller with improved multipower sliding mode approaching law with sideslip angle and slew rate constraints was designed.The simulation verified that during track tracking,the slew rate and sideslip angle It is within the safety limit area,which guarantees the safety in the course of track tracking.