Research On Trajectory Optimation And Precision Guidance Technology Of Small UAV Airborne Guided Bomb

Based on the requirement of small UAV airborne guided bomb,combined with the current situation and developping trends of trajectory optimation and precision guidance technology of small UAV airborne guided bomb,the trajectory optimation of guided bomb,approximate optimal guidance method,the multi constrained optimal guidance law consider terminal constraints and seerker's field of view,precision guidance technology used strapdown seeker are deeply studied.The studies will provide theoretical and technology basis for improve and newly developed small unmanned airborn guided bomb.Aiming at the design of optimal trajectory problem for unmanned airborn guided bomb,the optimation model of guided bomb is established correspond with constraint conditions and first order necessary condition of the optimal solution.The optimal trajectory of small guided bomb with low initial velocity,guided bomb with large lift drag ratio,small high altitude supersonic unmanned platform guided bomb is obtained used hp-Radau Pseudo spectral method,the optimal trajectory scheme of three kinds of guided bomb is put forward based on the optimal trajectory.A nonlinear trajectory tracking guidance law is also provide for applied optimal trajectory to engineering,the simulation results verified the guidance law.For optimal glide problem of glide bomb with large lift drag ratio,the relationship between trajectory parameters is derived based on the condition of equilibrium glide.The analytical solutions of equilibrium glide trajectory parameters is obtained under fixed lift drag ratio,the maximum lift drag ratio corresponding to maximum gliding range is verified and the estimation method of gliding range is given.Under assumption that the aerodynamic parameters are not changed with the Mach number,the fixed lift drag ratio glide can be equivalent to constant dynamic pressure glide,the relationship between trajectory parameters is deduced under constant dynamic pressure condition,the guidance method of convert the maximum lift drag ratio flight to keep dynamic pressure with maximum maximum lift drag ratio flight is put forward,and the calculation method of dynamic pressure with maximum maximum lift drag ratio is provide.Used the relationship between flight path angle and dynamic pressure,the indirect method to control dynamic pressure used flight path angle is proposed.The simulation results shows that the trajectory obtained by guidance method in this paper is closely approximate to optimal trajectory obtained by hp-Radau Pseudo spectral method,the error is less than 5%.For the problem of optimal trajectory junction between glide phase and terminal phase,the on-line adaptive computing method of trajectory junction position for minimum maneuver trajectory and initial overload continuous trajectory in terminal guidance is presented and simulation results verify its effectiveness.The method calculate the trajectory junction position according to the flight status and teriminal constaints.For the problem that the look angle would larger than seeker's field of view when used the impact angle constraint guidance law.The convergence condition of look angle is deduced,on this basis,the guidance strategy consider seeker's field of view and impact angle is given.Base on the assumption of little angle,the state equation of seeker look angel is estalished,the optimal multi constraint guidance law consider the seeker field of view and terminal position,impact angle,overload is derivation used the method for solving optimal control problems with state constraints with(?1/?⁹)as weighted of objective funtion For terminal used trajectory shape guidance law,the analytic expression of seeker look angle is obtained as well as the guidance method consdider seeker's field of view and impact angle,the expression and guidance method is verified by simulation.For the problems of strapdown seeker in engineering application.The LOSR estimation model is established,as the strong nonlinearity of the estimation model,the strong track cubature kalman filter is used for LOSR estimation.According to the typical delivery condition of small guided bomb,the hit probability was analyzed by Monte Carlo method.To solve the strapdown system guidance signal delay caused disturbance rejection rate?DRR?in?LOSR?estimate,the method add the time mark in INS and seeker data frame is proposed,so the main controller can use the same time INS and seeker data to decrease the guidance signal delay DRR.The mathematical and hardware-in-the-loop simulation indicates that the method greatly reduce the guidance signal delay DRR.Under the assumption of flight path angle keep constant,the total capture area's theoretical expressions of guided bomb with gimbaled seeker or strapdown seeker are put forward.and verified by simulation.