Trajectory Optimization And Control Parameters Design For Vertical-launching Ultra-short Range Missile Systems

The system of vertical launching missile has the advantages of fast response ability,high launching efficiency and 360 degrees without dead angle,large amount of loading,strong firepower,which is favorable to generalization,modularization,simple structure,reliable work,low cost and so on.However,the missile has the process of maneuvering at a large angle of attack at low Mach number when launched vertically.Aerodynamic nonlinear phenomenon is very obvious and flight distance and response time of the ultra-short-range missile are very short,the control system must have good rapidity and dynamic quality.In this paper,the nonlinear aerodynamic force and torque modeling,trajectory optimization and thrust scheme design,nonlinear control system design and so on are carried out with ultra-short-range vertical missile as the research object.Firstly,according to the characteristics of maneuvering flight with large angle of attack in fast turning during vertical launch,analysing the force and moment of missile,establishing the nonlinear model of force and torque for large angle turn of ultra short range vertical missile?dynamics and kinematics model of ballistics,constructing the basic theoretical model for further research.Secondly,there is a coupling phenomenon between the thrust of the engine and the motion of the projectile in the fast turning section of the missile.According to flight characteristics of the vertical launching missile,the trajectory is designed in sections,the original problem is transformed into the parameter optimization problem,designing flight constraint condition of the missile.The trajectory optimization model is established under the condition of multiple constraints and multiple stages.The trajectory optimization problem is transformed into a nonlinear programming problem based on hp-pseudospectral method,obtaining the scheme trajectory.Thirdly,the nonlinear attitude control law based on Lyapunov stability theory and Backstepping method is designed for the nonlinear dynamic model of missile maneuvering at high angle of attack and results of trajectory optimization.The simulation results show that the Backstepping control method has good tracking accuracy and stability.Fourthly,considering the effect of aerodynamic modeling error on the control system,designing nonlinear disturbance observer(NDO),proposing a Backstepping control method based on NDO.The simulation results show that the controller has a certain ability of active disturbance rejection.Finally,because the structure of nonlinear disturbance observer is complex,the structure of sliding mode control is simple to realize,it has "invariance" for internal parameter perturbation.Combined with the advantages of sliding mode and Backstepping control,a Backstepping controller based on sliding mode is designed for simulation.Simulation results show that the designed Backstepping autopilot based on sliding mode has good stability and robustness.