Research On The Guidance And Control Method Of Strapdown Guidance System

It is the mission of precision-guided weapon to strike enemy targets accurately,and the guidance control system of precision-guided weapon is the key to accomplish this mission.The strapdown guidance system can realize the closed loop of guidance control loop of precision guidance weapon by directly fixing the detector to the projectile body or installing the detector to the semi-strapdown frame,and achieve miniaturization and low cost by eliminating the gyroscope in the seeker.In this paper,based on the design of an airborne light-duty air-to-surface missile guidance control scheme using the strapdown guidance system,the guidance methods,control methods and semi-strapdown seeker control techniques under the strapdown guidance system are studied.Firstly,the strapdown guidance method is studied and its guidance precision is analyzed.On the basis of establishing the relative motion model of missile-target,two kinds of guidance schemes based on integral proportional guidance and proportional guidance are given in the strapdown guidance system,and the guidance precision under the two guidance schemes is studied respectively by using linear adjoint method.The purpose of the guidance accuracy analysis is to optimize the subsystem indexes on the premise of ensuring the hit accuracy.In this paper,the influence degree of each error source on the guidance accuracy in the missile guidance control loop is obtained under the strapdown guidance system,which can be used to establish the performance index system of the key subsystem.Secondly,the robust design of the stable loop under the strapdown guidance system is studied.Based on the model of missile control,the stability loop of missile is designed by using analytic method.In order to obtain the robust stable loop,the method of weight function selection is discussed based on the Hinf control theory.Furthermore,considering that the uncertainty of the missile stability loop model is mainly caused by the attack angle perturbation,a model describing the attack Angle perturbation is established,and the model is designed based on the theory of ? synthesis.Theoretical analysis and numerical simulation results show that the proposed controller design method takes the stability loop robustness into account and the design results meet the requirements of the indicators.Thirdly,the control method of semi-strapdown seeker stabilization platform is studied.In the conventional control scheme,the semi-strapdown seeker's pitch and yaw channel are decoupled.Due to the sensor configuration of semi-strapdown stable platform,the frame angular velocity can be obtained by mathematical calculation.In this paper,a gain scheduling controller based on external frame angular velocity is presented.Based on the finite time bounded theory,the sufficient conditions of finite time bounded by linear matrix inequality are derived under the linear time-varying parameter model,and the control gain matrix is obtained by using the linear matrix inequality tool.The gain of the controller is automatically adjusted according to the frame angular velocity calculated by the semi-strapdown stabilization platform.The simulation results show that the proposed controller can effectively reduce the pitch yawing channel coupling while having higher control accuracy when base disturbance exists.Finally,a hardware-in-the-loop simulation platform for semi-active laser-guided missile is established.The platform can carry out real-time simulation tests on the main subsystems and the whole guidance control loop of the missiles with the strapdown guidance system to verify the system's working time sequence,the performance of each subsystem and the overall performance.This paper proposes solutions to some key problems in the main control part,the motion simulation part and the signal simulation part of the hardware-in-the-loop simulation platform,and analyzes the relationship between the equipment installation error and the angle measurement error of the seeker in the simulation system.In addition,based on the simulation platform,the calibration method of the strapdown semi-active laser seeker is given in this paper,and the commonly used interpolation algorithm is studied to reduce the angle error of the strapdown semi-active laser seeker during the processing and assembly process.