A fault-tolerant control method for quadrotor UAV for motor failure

Abstract

The present invention proposes an active fault-tolerant control method for quadrotor UAV motor faults. First, construct a quadrotor UAV coupling dynamics model containing failure coefficients to quantify the fault degree of the quadrotor UAV motors; secondly, respectively Establish an independent state estimator for each motor of the rotor UAV; again, obtain the residual error according to the results of the state observer and the ideal state of each motor; then, aim at the problem of false detection of faults that may be caused by sensor measurement errors or external environmental interference , an adaptive threshold design method based on the system model is given. The designed threshold is adaptively adjusted according to the state residual of the drone at the last moment. When the fault parameter exceeds the threshold, the motor will be considered to be faulty; finally, By estimating the fault amplitude of each motor, reconstructing on the basis of the nominal controller of the UAV, the fault-tolerant controller of the rotor UAV that can adjust the motor fault is automatically generated online, and the rotor no-fault controller is completed in the case of a motor phase failure. Man-machine flight is safe and stable.

Description

technical field [0001] The invention relates to a fault-tolerant control method for a quadrotor unmanned aerial vehicle aimed at motor faults, which is applicable to the control system of a civil quadrotor unmanned aerial vehicle with easily damaged motors and limited computing power. The invention relates to the technical field of unmanned aerial vehicle control. Background technique [0002] Quadrotor UAV is a non-linear, strongly coupled and uncertain underactuated system. Compared with other aircraft, its salient features are: (1) Small size, flexible takeoff and landing, and can complete vertical takeoff and landing in a small area ; (2) Quadrotor UAV can complete maneuvering flight at low altitude, the flight speed can reach tens of meters per second, the steering is flexible, and it has strong maneuverability; (3) Simple structure, low production cost, and easy maintenance . Due to the various advantages of the quadrotor UAV, it can replace humans to enter certain ex...

AI Technical Summary

Problems solved by technology

[0005] Patent application number 201810207537.3 proposes a fault-tolerant control method for quadrotor UAVs based on an adaptive fault estimation observer, but there are two problems: (1) The patent does not consider fault diagnosis and isolation. When the environment changes rapidly, it is easy to misjudge the UAV's own situation, which will cause the UAV to lose stability without failure, and seriously affect the control accuracy and stability of the UAV under non-fault conditions; (2) The H∞ algorithm used in this patent is more dependent on the accuracy of the system model, and the fault estimation takes 5 to 6 seconds, so it is reasonable to speculate that the control effect is not good before the fault estimation, so it will be relatively difficult in actual use. Limit to a great extent

Therefore, the stability of UAV control and the rapidity of fault estimation need to be improved.

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