The Research Of Guidance And Control Method In Terminal Guidance Phase

In this thesis, the Anti-missile interceptor is taken as the research subject. According to the guidance and control requirements of the Anti-missile missile in the terminal guidance phase, the main work and achievements on guidance and control mechanism are described as follows:First of all, the principle of relative motion equation between missile and target in three-dimensional space is researched. Three modeling methods of 3-D relative motion of missile-target were proposed here. They are relative dynamics models in polar coordinates, columnar coordinates and in the line of sight (LOS) fixed coordinates. The comparison about the three models is studied. This section is important because the complexity of the relative motion models affects the design of guidance and control system. The three relative motion models here have certain significance on engineering practice.Second of all, by using the relative motion under the line of sight fixed coordinates, two new guidance laws are proposed. One is a state feedback sub-optimal control law based on the state-dependent Riccati (SDRE) technique. The other one, based on the idea of zeroing normal speeds of the LOS, is a robust terminal guidance law designed by the method of dynamic inversion. The two laws are both effective comparing with General Ideal Proportional Guidance Laws (GIPN).Then, considering engineering practice, when intercepting a maneuvering target, the dynamic nature of missile body and its approximate linearization both has effects on the miss distance and guidance quality. To solve this problem, basing on sliding mode variable structure theory,this section proposed an integrated nonlinear guidance and control strategy which taking both missile control loop character and guidance loop character into account. This strategy can effectively solve big maneuver of the target and favorable guidance quality is still achievable even if the control loop is not compensated.In the end of this thesis, the six-degree-freedom mathematic model and simulation model of the interceptor are established. And the six-degree-freedom digital simulation is carried out for the terminal guidance stage. To analyze the accuracy, Monte-Carlo simulation results are presented demonstrating that the performance of the guidance laws and attitude control methods of the interceptor designed in this thesis can satisfy the request of high accuracy and fast response.