The Guidance Law And Autopilot Design For Bank-To-Turn Missiles

With the rapid development of national defense industry of our country, the demand of military missions is increasingly diverse, and the requirement for maneuverability, stability and strike effect of missiles are higher. Through the design of missile guidance laws suitable to produce corresponding guidance commands, and design of high performance autopilot to track the command fast and accurately, the missile can fly along the ideal trajectory and complete the specific combat missions finally. In this paper, regarding BTT(Bank-to-Turn) missile with air actuator as its executive mechanism as the research object, to complete the accurate strike with terminal impact angle constraint as the ultimate goal, in view of the dynamic delay characteristics of actuator, the design of the guidance law considering target maneuvering and autopilot considering aerodynamic parameter perturbation and cross coupling of three channel, the research will be made, and the main research contents are as follows:1) On one hand, the equations of relative motion between missile and target are given. With these equations, two kinds of guidance models are built according to whether the dynamic delay characteristics of the actuator are considered or not. Based on the two models built above, for the problem of terminal impact angel constraint, two kinds of finite-time guidance laws are designed based on the sliding mode theory. And the equilibrium point of the system states is proved to be stabile with finite time according to the finite-time stability theory. Through extensive simulations, the two guidance laws designed in this paper are proved to be able to meet the corresponding requirements.2) On the other hand, the dynamic models of pitch, yaw and roll channels are built without considering three channel couplings of autopilot. During the building of the models, the aerodynamic coefficients are chosen with nominal values, and aerodynamic coefficient perturbations are regarded as the equivalent disturbance. Based on the three models built above, the guidance laws are designed with sliding mode theory, respectively. Due to the important role of the roll channel in suppressing the couplings, in order to make the roll channel have a better response performance and be more close to practical engineering, the autopilot considering actuator’s first order time delay is designed for the roll channel. Then, the system states are proved to be stabile with finite time. Finally, the control signals of the three channels’ autopilots designed separately are substituted into the BTT missile model with couplings and aerodynamic coefficient perturbations, in order to test whether the autopilots designed have enough robustness to them. Through extensive simulations, the autopilots designed in this paper are proved to be able to meet the corresponding requirements.