Research On Motion Control Method Of Hovercraft With Time Delay

The fully cushioned hovercraft is a high-performance ship which has the advantages of high-speed and amphibious.It is widely used in military and civil fields.Because of the particularity of the hovercraft sailing off the water,its internal characteristics are more complex.Scholars at home and abroad have done a lot of research on this.At the same time,the working state of the hovercraft is closely related to its own state and working conditions.Its complex marine environment and modeling mechanism make the system uncertain.The high-speed navigation characteristics make the system highly nonlinear.At the same time,the time-delay characteristics of the motion are also factors that need to be considered in the design of the motion control system.In order to make the motion control system design close to the real ship characteristics and give full play to the excellent characteristics of the hovercraft,this paper focuses on the research of the motion control method of the hovercraft with full lift under the condition of time delay,using the ADRC method to design the controller,and introducing the time delay term into the system,using the Smith predictor compensator,optimal control and other methods,finally realizing the full lift hovercraft Motion time-delay compensation control.First of all,a four degree of freedom motion simulation model of air cushion vehicle is established by using the modular modeling method.The fixed coordinate system and the moving coordinate system of the spatial motion model,as well as the rotation transformation relationship between the two coordinate systems are simply discussed and established.In the moving coordinate system,the duct propeller,air rudder and crosswind door of the air cushion vehicle are modeled respectively,and the aerodynamic model and hydrodynamic model of the air cushion vehicle are established.Finally,the four degree of freedom dynamic and kinematic equations of the air cushion vehicle are listed.The equations are solved by the freezing and thawing algorithm and the fourth-order Runge Kutta algorithm and transformed to the fixed coordinate system.The four degree of freedom motion model of air cushion vehicle is simulated.In this paper,the direct motion characteristics,pitch difference rotation characteristics and steering rotation characteristics of the hovercraft are studied by simulation.Secondly,SF coordinate system is introduced into the guidance loop of track control of hovercraft.Based on the traditional Los guidance method,a forward-looking Los guidance controller with integral is designed to enable the hovercraft to track any curve track.At the same time,the track tracking simulation of the hovercraft on the circular track is carried out under the condition of wind and no wind.The common PID double loop control is used in the control link.Then,for the rate of gyration control and time delay problems encountered in the air cushion vehicle heading control,the method of auto disturbance rejection control is adopted.Through the reasonable design of tracking differentiator,expansion observer,nonlinear feedback and reasonable parameter selection,the rate of gyration control of hovercraft is realized.At the same time,the time-delay term is introduced into the system equation.In order to compensate for the influence of time-delay term,this paper adopts the method of auto disturbance rejection control and Smith predictor compensator to solve it,and carries out the simulation of heading and track tracking respectively.At last,the system state equation with time-delay is transformed into the system state equation without time-delay by using the idea of time-delay transformation,and the quadratic optimal method is used to improve the auto disturbance rejection controller,which reduces the parameters needed to be designed in the extended observer,and realizes the motion control of the air cushion vehicle with time-delay.The track tracking control of hovercraft with time-delay is realized by simulation,and the performance of time-delay compensation and time-delay conversion methods are compared.