Wind and Actuator Fault Estimation for a Quadrotor UAV Based on Two-Stage Particle Filter

This paper investigates the problems of wind and actuator fault estimation for a quadrotor unmanned aerial vehicle(UAV).To e®ectively assess the safety and reliability of a quadrotor UAV in the presence of unknown wind disturbances,a two-stage particle filter(TSPF)scheme is proposed to obtain the simultaneous estimation of winds and actuator faults that may degrade the performance of the vehicle.In this scheme,the first-stage particle filter is used to estimate the states of the quadrotor UAV,and the second-stage particle filter is designed to produce estimates of unknown parameters,including the wind disturbances and actuator faults.To mitigate the degeneracy and impoverishment issues,the second-stage particle filter admits a parallel implementation of increased particle samplings for the wind and actuator fault estimation.Finally,simulation results are presented to demonstrate the e®ectiveness of the proposed scheme.

Simultaneous state and actuator fault estimation for satellite attitude control systems

In this paper, a new nonlinear augmented observer is proposed and applied to satellite attitude control systems. The observer can estimate system state and actuator fault simultaneously. It can enhance the performances of rapidly-varying faults estimation. Only original system matrices are adopted in the parameter design. The considered faults can be unbounded, and the proposed augmented observer can estimate a large class of faults. Systems without disturbances and the fault whose finite times derivatives are zero piecewise are initially considered, followed by a discussion of a general situation where the system is subject to disturbances and the finite times derivatives of the faults are not null but bounded. For the considered nonlinear system, convergence conditions of the observer are provided and the stability analysis is performed using Lyapunov direct method. Then a feasible algorithm is explored to compute the observer parameters using linear matrix inequalities （LMIs）. Finally, the effectiveness of the proposed approach is illustrated by considering an example of a closed-loop satellite attitude control system. The mance in estimating states and actuator faults. It also successfully. simulation results show satisfactory perfor- shows that multiple faults can be estimated