Research On Terminal Guidance And Control For Near-space Interceptor

Hypersonic vehicle in near space has been one of the key research fields in long-distance precision-beating weapons all over the world.So how to intercept the near-space vehicle is an important problem for national security.Because of the huge relative velocity between the target and the interceptor,hit-to-kill technology is usually used,which requires high precision for the guidance and control system.In this paper,the terminal guidance and control of the near-space interceptor are researched.A terminal guidance law and a control law are designed.The major contents of this paper are consisted of the following parts.The dynamic model of the near-space interceptor is studied.Referring to the kinetic energy warhead of the THAAD of America,the near-space interceptor system is designed.On the basis of the model,the dynamic equations of the interceptor are established.Then the forces and momentums acted on the interceptor are analyzed and modeled.The terminal guidance of the near-space interceptor is studied.Firstly,the three-dimensional relative motion equation between the interceptor and the target is established.On the basis of the relative motion equation,a sliding mode variable structure guidance law is designed for the terminal guidance in near space intercept.Then the stability of the guidance system is proved on the basis of Lyapunov theorem of stability.For realizing the guidance law,an estimator on upper bound of the maneuverability of the target is designed.A solution to the chattering of the sliding mode variable structure guidance law is proposed.Finally,interception for the target with three kinds of maneuvering is simulated,which are uniform motion in a straight line,constant maneuvering and sine maneuvering.By contrast of the proportional navigation and the sliding mode variable structure guidance,the latter behaves better in ballistic characteristics and distribution of overload commands.What's more,the sliding mode variable structure guidance is probe to realize for the near-space interceptor.The control of the near-space interceptor is studied.Firstly,a dynamic-inversion controller is designed based on the principle of time scale separation.Then the mechanism of the side window detection is studied.An attitude control strategy under the constraints of side window detection and guidance is proposed.For realizing the command of attitude control,a PWPF modulator between the control law and the attitude control engines is designed,which can modulate continuous control commands to a series of switch instructions.The switch instructions can be identified by the attitude control engines.Finally,the control system is simulated in near space intercept.The results show that the control law behaves well in rapidity and accuracy.Finally,the six-degree-of-freedom simulation for the guidance and control system of the interceptor is done.The results show that the guidance and control system is valid.