Reentry aircraft finite time control method based on disturbance observer

Abstract

The invention discloses a reentry aircraft finite time control method based on a disturbance observer and relates to the reentry aircraft finite time control method. The reentry aircraft finite time control method belongs to the field of aircraft control technology. The reentry aircraft finite time control method comprises the following steps: a first step, establishing a reentry aircraft dynamic model, presenting a finite time gesture tracking task; a second step, performing feedback linear processing on a model which is established in the first step; a third step, providing a finite time control law; a fourth step, providing a finite time disturbance observer for estimating system uncertainty and outer disturbance; and a fifth step, providing a finite time global sliding mode control method based on the disturbance observer, and effectively improving tracking precision of a gesture control system through substituting an estimated disturbance value into the control law. The reentry aircraft finite time control method has functions of improving system error convergence speed, preventing a singular problem and improving uncertainty of the controlled system to the parameter, global robustness of outer disturbance and tracking precision.

Description

technical field [0001] The invention relates to a finite-time control method of a re-entry aircraft, in particular to a finite-time control method of a re-entry aircraft based on a disturbance observer, and belongs to the technical field of aircraft control. Background technique [0002] During the re-entry flight of the aircraft, the range of dynamic pressure Mach number is large, the airframe presents strong nonlinear characteristics, and the coupling between each channel is serious, and the flight process is accompanied by many interferences that cannot be fully predicted. Therefore, it is necessary to design a strong adaptive attitude control law with strong robustness and fast response to commands. [0003] At present, the non-linear control methods that are widely used include fuzzy control, optimal control, dynamic inverse control, and sliding mode variable structure control. Among them, sliding mode control is a strong robust nonlinear control method, which is invar...

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Problems solved by technology

However, there is an arrival period in the above sliding mode control, and the system is less robust in the arrival period

At the same time, there is a chattering problem in the sliding mode control. The common method is to introduce a boundary layer to continuously approximate the discontinuous sign function. This method has a certain effect on weakening the chattering, but it will lead to a decrease in the tracking accuracy and robustness of the system.

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