Research Of Terminal Guidance Approach For Hypersonic Glide Vehicle

Relying on the aerodynamic shape of large lift-to-drag ratio, the hypersonic glide vehicle can take an unpowered long-distance gliding flight in near space. When the hypersonic glide vehicle gets close to the target, it takes a rapid dive to hit the target. The hypersonic glide vehicle has a great capacity of strong penetration and damage. This paper takes the hypersonic glide vehicle as the research objective and mainly studies the terminal guidance of the vehicle with full consideration of complex multi-constraints and and motion coupling.First, considering various complex constraints of the dive phase, this paper proposes a close-loop guidance approach based on the Radau pseudo-spectral method and the theory of differential flat. The kinematic and mathematic models which consider all kinds of constraints of the dive phase were established. To reduce the negative influence of large hinge moment, the Radau pseudo-spectral method is adopted to generate the terminal trajectory considering the overload, the density of heat flow, the terminal constraints and the hinge moment at the same time. Based on the theory of differential flat, the feedback guidance law is designed to eliminate the influence of initial state errors and track the terminal trajectory well. The simulation shows that this method can considerably reduce the influence of the hinge moment and has certain robustness for the initial deviation at the same time.Second, considering the terminal angle constraint, the adaptive proportional guidance and the robust optimal guidance based on terminal sliding mode are studied. Based on the analysis of the parameters of the proportional guidance law and the motion characteristics of dive and turning planes, the adaptive updating strategy of the guiding parameters is designed. To improve the performance of the traditional optimal guidance law against uncertain factors, the robust optimal guidance law based on the control theory of terminal sliding mode is proposed to meet the mission demand, and the hyperbolic tangent function is used to mitigate the high frequency chattering caused by the sliding mode switch.Finally, considering the motion coupling problem of the hypersonic glide vehicle, a nonlinear guidance approach based on Lie group control theory is studied. Based on Lie Group structure and the relative motion between the aircraft and the target, a geometric vector model is designed. By using the generalized proportional differential control law and Lie Group, the guidance law of the terminal phase which satisfies the terminal angle constraint is designed and the effectiveness of the method is verified by simulation.This paper systematically studies the terminal guidance of the hypersonic glide vehicle and explores a new method of terminal guidance, offering certain value for the terminal guidance system design for the hypersonic cruise vehicle and reusable vehicle.