Fault-tolerant control method for quadrotor UAV based on observer

Abstract

The invention relates to the quadrotor unmanned aerial vehicle fault-tolerant control, and aims to realize attitude stability under the condition of an actuator fault of a quadrotor unmanned aerial vehicle. The technical scheme adopted by the invention is that an observer-based quadrotor unmanned aerial vehicle fault-tolerant control method includes the following steps: first defining an inertia coordinate system {I}, a body coordinate system {B} and a target coordinate system {Bd}, and through analysis of an action principle of the actuator on the quadrotor unmanned aerial vehicle, an unknown diagonal matrix is utilized to represent influence of an actuator fault on kinetic characteristics of the quadrotor unmanned aerial vehicle, and a nonlinear kinetic model when a fault occurs in the quadrotor unmanned aerial vehicle actuator is obtained; a unit quaternion-based attitude representation method is adopted; and an observer technology based on an immersion-invariant set method is adopted to observe the actuator. The observer-based quadrotor unmanned aerial vehicle fault-tolerant control method provided by the invention is mainly applied to quadrotor unmanned aerial vehicle design and control occasions.

Description

technical field [0001] The invention relates to a fault-tolerant control problem of a quadrotor unmanned aerial vehicle. Aiming at the problem of attitude control when the actuator of quadrotor UAV fails, a nonlinear adaptive fault-tolerant control method based on immersed-invariant set observer technology is proposed. Background technique [0002] The four-rotor UAV relies on the rotation of four motors to drive the propeller to rotate to generate lift, and achieves pitch, roll, yaw and other actions by changing the speed of different motors. Affected by the control stability of the aircraft and its own technology, the continuous high-speed rotation of the motor and propeller greatly increases the probability of failure. In addition, during the flight of the aircraft, it will inevitably be affected by external disturbances (such as obstacle impact, rain, strong wind, strong airflow, etc.), and the aerodynamic characteristics of the aircraft itself will undergo strong chang...

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Problems solved by technology

[0005] However, the current various fault-tolerant control methods have their own limitations

For example, when performing dynamic modeling on actuator faults, it is regarded as an external disturbance moment, which is approximated to a large extent, and it is difficult to reflect the real impact of actuator faults on UAVs (Journal: Control Theory and Applications; Authors: Huihui Yang, Bin Jiang, Ke Zhang; Year of publication: 2014; Article title: Direct self-healing control of quadrotor helicopter attitude system; page number: 1053-1060); The dynamic model of the rotor UAV has been linearized, and the theory proves that only a stable conclusion near the equilibrium point can be obtained. When the actuator fails, the attitude of the aircraft will change suddenly, and in most cases the attitude of the aircraft will deviate from the equilibrium point. Large location, difficult to guarantee the application range of the controller (Journal: IEEE Transactions on ControlSystems Technology; Author: Z.T.Dydek, A.M.Annaswamy, E.Lavretsky; Date of publication: July 2013; Article title: Adaptive Control of Quadrotor UAVs: a Design Trade Study with Flight Evaluations; pages: 1400–1406); the passive fault-tolerant method has a limited application range, it is difficult to achieve robustness compatibility with external disturbances and actuator failures, and the control effect is poor, while the active fault-tolerant control method requires fault Diagnosis and fault isolation, and fault reconstruction based on this, the algorithm is complex and difficult to implement engineering applications (Journal: Proceedings of the Institution of Mechanical Engineers, Part I, Journal of Systems and Control Engineering; Author: T.Li, Y.M.Zhang , B.W.Gordon; Year of publication: January 2012; Article title: Passive and Active Nonlinear Fault-Tolerant Control of aQuadrotor UAV Based on Sliding Mode Control Technique; Pages: 12-23)

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