Design method of four-rotor fault-tolerant controller based on nonlinear observer

Abstract

The invention presents a design method of a four-rotor fault-tolerant controller based on a nonlinear observer. The method includes the following steps: establishing a dynamic model of a four-rotor unmanned aerial vehicle (UAV), and dividing the UAV system into an attitude subsystem and a position subsystem; for the attitude subsystem, establishing a fault model, designing a nonlinear fault observer, carrying out real-time detection and online estimation on an unknown actuator fault, and designing a fault-tolerant controller based on a fast non-singular terminal sliding mode method by using the obtained fault estimation information; and for the position subsystem, inversely solving the control rate and the desired attitude angle of the position subsystem by combining a backstepping methodand a sliding mode method and designing an intermediate virtual quantity. A four-rotor UAV is enabled to track the desired position and yaw angle even when the actuator fails, so as to ensure the stability of the pitch angle and roll angle.

Description

technical field [0001] The invention relates to a design method of a four-rotor fault-tolerant controller based on a nonlinear observer, specifically a design method of a nonlinear fault observer and a sliding-mode fault-tolerant controller of a four-rotor UAV, which belongs to the automatic control of aircraft technology field. Background technique [0002] Compared with traditional aircraft, quadrotor aircraft has the advantages of flexibility, easy operation, low cost, and vertical take-off and landing. At present, it has unique advantages and application prospects in emerging fields, such as aviation logistics, ecological environment monitoring, power detection, closed space monitoring, surveying and mapping, etc. However, quadrotor technology still faces the following two serious challenges. On the one hand, it cannot handle unknown situations by itself because external disturbances have a great influence on the stability of the flight control system. During the flig...

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Problems solved by technology

However, the implementation of this technology on quadrotor drones is relatively rare

[0005] On the other hand, in terms of fault-tolerant control, the main research results are focused on state-feedback fault-tolerant control based on state observers, but due to the coupling relationship between state estimation and fault estimation, it is difficult to design the state feedback matrix when designing a fault-tolerant controller , increasing the difficulty of fault-tolerant controller design

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