Aircraft tracking control direct method with input saturation

Abstract

The invention discloses an aircraft tracking control direct method with input saturation to solve the technical problem that input saturation tracking control is difficult to realize if an aircraft has uncertain parameters and external disturbance exists. The method includes the steps: firstly, establishing an aircraft model with a time-varying uncertain parameter and external disturbance, and converting a non-linear system into a linear parameter varying error system through linearization along a time-varying path; then, obtaining a convex polyhedron description form of the error system through a tensor product model transform method, and directly describing a saturation effect of a control quantity also through a convex polyhedron structure if the state of the system is restricted within some local scope; and finally, on the basis of the robustness H-infinite theory, obtaining an input saturation controller by solving linear matrix inequations with limited number, the controller accurately tracking instructions and effectively inhibiting disturbance within the system state local range. In particular, if state constraint matrixes are made to be equal to control matrixes, saturation of the controller can be prevented.

Description

technical field [0001] The invention relates to a direct method of aircraft tracking control with input saturation, which is mainly applied to input saturation tracking control of aircraft with uncertain parameters and external disturbances under a large flight envelope and effective suppression of external disturbances, belonging to aircraft control technology field. Background technique [0002] For modern high-performance aircraft, especially for unmanned aircraft such as drones, in order to pursue higher lift-to-drag ratio and maneuverability, the saturation limitation of actuators is inevitable. Furthermore, the uncertain factors in the aircraft model and the interference of the external environment make it more difficult to design the saturation control rate to achieve robust tracking of command signals and effective suppression of external disturbances. In the prior art, the low-gain control method can avoid the saturation phenomenon, but when the system tends to a s...

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Problems solved by technology

Xu et al. (B.Xu, S.Wang, D.Gao, Y.Zhang, and Z.Shi, "Command filter based bust nonlinear control of hypersonic aircraft with magnitude constraint on states and actuators," Journal of Intelligent & Robotic Systems, 73(1-4):233-247, 2014) for the presence of parameter uncertainty and state For the aircraft system with limited magnitude and actuator amplitude, a robust nonlinear controller based on command filter is designed. These methods belong to the category of indirect methods, the design process is complicated, and often only the closed-loop system signals can be consistent and ultimately bounded.

[0003] On the other hand, the flight envelope of the aircraft is wide, and the flight environment is complex and changeable, resulting in drastic changes in its aerodynamic parameters and environmental variables. If a fixed control rate is designed to meet the desired flight quality, it is often very conservative, even in not possible in some cases

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