Self-adaptive index time varying slip form posture control method of reentry flight vehicle

Abstract

The invention relates to a self-adaptive index time varying slip form posture control method of a reentry flight vehicle, belonging to the technical field of flight vehicles. The method comprises the steps of firstly establishing a posture motion equation in a mode that a powerless reentry flight vehicle model is used as an object; secondly modifying the equation into the mode of an MIMO (Multiple Input Multiple Output) affine non-linear system, further applying a feedback linearization principle to carry out linearization processing so as to obtain a three-channel linearization model of pitching, rolling and yawing; aiming at the obtained linearization system, designing a modified self-adaptive index time varying slip form controller; and subsequently obtaining a control moment instruction for the posture control of the reentry flight vehicle, and inputting the control moment instruction into the reentry flight vehicle so as to control the posture. By combining the index time varying slip form control with a self-adaptive method, the problem of excessive adaptation of switch gain in the self-adaptive slip form control is solved to a certain extent, the uncertainty of system parameters and the influence of external disturbance can be suppressed effectively, and the precise posture control is realized.

Description

technical field [0001] The invention relates to an adaptive exponential time-varying sliding mode attitude control method for a reentry aircraft, belonging to the technical field of aircraft control. Background technique [0002] For the re-entry vehicle, the flight conditions (airspace and speed domain) change in a large range during the re-entry process, and the coupling between channels is serious, showing strong nonlinear dynamic characteristics. In addition, the existence of various uncertain external disturbances and the inability to accurately know the aerodynamic characteristics of the aircraft make its attitude control extremely complicated. The key problem to be solved in the design of the reentry vehicle control system is to suppress the influence of the above nonlinear, strong coupling and uncertainty on the system performance. [0003] Although various advanced nonlinear control methods (such as dynamic inverse, feedback linearization, trajectory linearization,...

AI Technical Summary

Problems solved by technology

However, the shortcomings of ordinary sliding mode control are: 1) the arrival stage is not robust; 2) the chattering problem; 3) the selection of the switching gain in the control law

However, for reentry vehicles, the reentry process is complex and changeable, and it is not easy to obtain these upper bounds of uncertainty

If the value of the switching gain is too large, the robustness of the system is strong, but the chattering is serious, and it is easy to stimulate the high-frequency unmodeled dynamics of the system to cause system instability; if the value of the switching gain is too small, the chattering is small, but the system is anti-interference Weak ability and poor robustness

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