Fault diagnosis for a UAV using unknown input observer


INTERNATIONAL JOURNAL OF SUSTAINABLE AVIATION, vol.2, no.4, pp.309-326, 2016 (ESCI) identifier

  • Publication Type: Article / Article
  • Volume: 2 Issue: 4
  • Publication Date: 2016
  • Doi Number: 10.1504/ijsa.2016.082198
  • Journal Indexes: Emerging Sources Citation Index (ESCI)
  • Page Numbers: pp.309-326
  • Keywords: flight controls, actuator fault detection and isolation, quadrotor modelling, controller, fault tolerant control
  • Anadolu University Affiliated: Yes


In this paper a fault tolerant control strategy for a quadrotor is proposed in the presence of actuator faults. A linear mathematical model which is derived from nonlinear model by calculating the Jacobian matrix of the system is used to represent the quadrotor dynamics in MATLAB/Simulink environment. Observer-based state estimation approach which is widely used in fault tolerant area is chosen to detect and isolate faults in quadrotor system. Generalised observer scheme (GOS)-based unknown input observer (UIO) whose principle to make the state estimation error de-coupled from the unknown inputs (disturbances) is utilised to detect and isolate the actuator faults. In fault-free condition, linear quadratic tracking (LQT) is preferred to stabilise the quadrotor to obtain faster system response. When it comes to faulty case, LQT cannot handle compensation of steady-state error owing to power loss in actuator. Therefore linear quadratic regulator (LQR) with integral action is selected by fault diagnosis unit to compensate steady-state error due to actuator fault. Simulation results are presented to demonstrate the performance of the proposed fault tolerant control strategy.