Research on the Final-stage Guidance Method of a Launch Vehicle Considering Modeling Errors
After the ignition of the final-stage engine,the launch vehicle guided by the guidance system will finally reach the orbit injection point and obtain an injection speed,and the satellite will enter the operational orbit.The final-stage flight dynamics model of a launch vehicle is in the form of nonlinear differential equations,which makes it difficult to obtain the attitude change characteristics of the launch vehicle by means of analytical methods and then control the state variables during the flight process of the launch vehicle.In this paper,the orbit injection constraint conditions of the launch vehicle are converted to a performance index function for optimal control,and the dynamic equations are solved by means of the combination of the Pontryagin minimum principle and the Newton gradient method,so that the final flight standard orbit is obtained.In the process of modeling the launch vehicle dynamics,due to the difficulties such as the parameters cannot be accurately measured,there are inevitably modeling errors,and thus the actual flight orbit of the launch vehicle will deviate from the standard one.The model is linearized,and the state feedback is introduced,which can make the actual flight orbit close to the standard one and improve the accuracy required for satellites loading into orbits.The simulation results show that the guidance algorithm can effectively reduce the orbit injection error of the launch vehicle.
国家科技期刊平台
NSTL
万方数据
维普
