| In order to fufill technical requirements of strapdown guided munitions, thisdissertation mainly studied the effect of disturbance rejection rate (DRR) of strapdownseeker to guidance performance, the online identification and inhibition technique of DRR,guidance information estimation and integrated guidance and control (IGC) techniques.The forces and moments of missile during flight were analyzed, the6-DOF dynamicsand kinematics model was established, and the aerodynamic forces were calculated andanalyzed using Computational Fluid Dynamics (CFD) numerical simulation. The resultsprovided model basis and data support for the overall scheme design of strapdown guidedmunitions.The generation mechanisms of DRR with strapdown seeker were studiedsystematically, the effects on guidance performance of DRR by different inducemets, i.e.,the different scale factors between detector and angular rate gyro, dynamics mismatch ofthe two sensors, and body elastic vibration, were also discussed. According to differentinducement of DRR, the stable regions of disturbance rejection rate parasitic loop (DRRPL)and guidance system with DRRPL were analyzed. Furthermore, the miss distance casued bythree different input error sources was studied by adjoint method, i.e., initial velocitydirection error, seeker zero error, and angular noise. The research provided theoreticalreferences to the guidance and control system design of strapdown guided munitions. Theresults demonstrated that the stability domain is closely related to the feedback form ofDRR, DRR level, and correlation parameters of guidance system; the guidance systembecome unstable and had low accuracy due to the effect of DRR; compared with Air-to-Air/Surface-to-Air missiles, projectiles attacking ground targets have loose constraint on theindex DRR; inhibition of DRR is the key technique urgent to be resolved for theengineering application of strapdown seeker.Currently, parts selection, process control, indexes biasing, or ground calibration usedin engineering cannot restrain DRR effectively, so the DRR online estimating and inhibitingapproach was proposed to reduce the impact of DRR on guidance system. According toDDR caused by scale factor error, the arithmetic using UKF was designed. Moreover, the method based on matching filter was deduced to make a uniform dynamic of two sensors.At last, frequency online identification combined with adaptive notch filter was used toprevent the influence of flexible vibration on DRR. Simulation results showed that theeffect of DRR to guidance system could be reduced and the guidance accuracy could beenhanced by using these algorithms.Due to the fact that the strapdown image seeker cannot measure the inertialline-of-sight (LOS) rate directly, an arithmetic estimating the LOS rate based on EKF wasdeveloped. The LOS rate decoupling expression under ideal condition was deduced. Andthe model estimating available guidance information based on EKF equation wasestablished. According to the features of operational use of the Man-portable guidedmunitions, the hit probability was analyzed by Monte Carlo method. The engineeringfeasibility of the guidance system was verified by hardware-in-the-loop simulation. Resultsshowed the technical approach of strapdown image seeker with estimation arithmetic ofguidance information was suitable for engineering application.At last, integrated guidance and control (IGC) arithmetic was derived based on infinitehorizon LQR theory. The non-linear suboptimal control method that has low computationalamount was obtained by θ perturbation approach. The IGC ideas and the traditionalseparate approach were analyzed comparatively. The analysis indicated that the flightstability could be guaranteed by IGC approach based on optimal control theory, moreover,the arithmetic was robust to aerodynamic parameter uncertainty; compared with traditionalmethods, IGC has advantages of lower miss distance, more uniform of control energydistribution, and higher flying stability. |
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