Research On Attitude Control For Hypersonic Reentry Vehicle

In recent years, hypersonic flight vehicle technology is developped rapidly with more strategic significance. Because the change of the flight aerodynamic environment in the process of reentry is very complex, at the same time, there are model uncertainties, as a result, it presents a bigger challenge for the design of the control system. General linear control system design methods are difficult to meet the requirements for hypersonic vehicle, researchers need to explore new nonlinear control methods. Based on the summary of the related literature, this paper fully analyzes the characteristics of the reentry flight and take reasonable simplification of model, establishes hypersonic vehicle model for control of the reentry phase. In addition, aerodynamic force and aerodynamic moment coefficient are given, and then establishes a model of the atmosphere in order to present more realistic reentry flight characteristics.Through the analysis of the open loop properties of system, and zero input response of the system, it is concluded that a s ingle channel controller design method is hard to meet the control demand because of the three-channel coupling characteristic.After analyzing and summarizing the existing nonlinear control method, firstly, back stepping and dynamic inversion methods are combined for the control system design, tracking differentiator is used to solve the problem of "differential explosion", at the same time the disturbance observer is designed based on the observation ability of extended state observer which is used to impr ove the robust of control system. Secondly, based on the time-scale separation principle makes the system finite time stable through the designing of finite time sliding mode and reaching law, which effectively improves the convergence speed and precision of the control system, otherwise high order sliding mode perturbation observer is adopted. This paper make full use of the backstepping, dynamic inversion, the sliding mode control and other advanced nonlinear control strategy to do some research on hypersonic flight vehicle reentry attitude control system. Aiming at providing some valuable results for the researcher who are exploring strategies about hypersonic vehicle reentry attitude control.