This paper investigates the integrated fault detection and diagnosis(FDD) with fault tolerant control(FTC) method of the control system with recoverable faults.Firstly,a quasi-linear parameter-varying(QLPV) model is set up,in which effectiveness factors are modeled as time-varying parameters to quantify actuators and sensors faults.Based on the certainty equivalency principle,replacing the real time states in the nonlinear term of the QLPV model with the estimated states,the parameters and states can be estimated by a two-stage Kalman filtering algorithm.Then,a polynomial eigenstructure assignment(PEA) controller with time-varying parameters and states is designed to guarantee the performance of the system with recoverable faults.Finally,mathematical simulation is performed to validate the solution in a satellite closed-loop attitude control system,and simulation results show that the solution is fast and effective for on-orbit real-time computation.
In this paper,consensus seeking of second-order systems without leaders is investigated under possibly switching directed graphs.Two consensus algorithms using different cooperative schemes are proposed and some information topology-independent criteria are obtained.For the first one,an eigenvalue-based analysis is taken to attain a sufficient and necessary condition for consensus seeking under fixed directed graph.For the second one,consensus can be achieved as long as the union of the switching graphs has a directed spanning tree frequently enough.Convergence analysis is presented,which is facilitated by an equivalent model transformation into a cascaded system.A novel sufficient and necessary condition for consensus seeking under switching undirected graph is also obtained using the same strategy.Moreover,robustness of both the algorithms to time-delays is studied under fixed directed graph.Illustrative examples are also provided to show the effectiveness of the theoretical results.
