Search

In this study, a novel control strategy of a three-inline array tethered spacecraft formation is proposed, based on a simplified non-linear model around the equilibrium point. The formation stability is analysed by using an interconnected system approach which deeply reveals the coupling characteristic among three spacecraft. It is shown that both individual control laws of spacecraft and the coupling effects can achieve the stability. The problems of fault-tolerant control and fault propagation are further discussed. Simulation results validate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

In this study, a novel control strategy of a three‐inline array tethered spacecraft formation is proposed, based on a simplified non‐linear model around the equilibrium point. The formation stability is analysed by using an interconnected system approach which deeply reveals the coupling characteristic among three spacecraft. It is shown that both individual control laws of spacecraft and the coupling effects can achieve the stability. The problems of fault‐tolerant control and fault propagation are further discussed. Simulation results validate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

A distributed fault estimation observer (DFEO) design is studied for multi‐agent systems with switching topologies. Firstly, a local fault estimation observer is presented for each agent system based on the relative output estimation error. Then by introducing global variables, a global fault estimation observer is proposed by utilising the average dwell‐time technique. Furthermore, a dissipativity‐based distributed observer is presented to handle external disturbances. Finally, simulation results are presented to illustrate the feasibility and effectiveness of the proposed DFEO strategy. [ABSTRACT FROM AUTHOR]

In this study, the problem of fault estimation observer design with finite‐time convergence specification for continuous‐time dynamic systems subject to external disturbances. First, the unknown input observer is constructed to achieve accurate estimation of the occurred fault and to guarantee robustness against the disturbance. Then a pole placement‐based fault estimation observer is constructed using time‐delay design such that the fault estimation error converges to zero in finite time. Unlike conventional literatures, the proposed fault estimator with finite‐time convergence specification does not contain discontinuous sign function. Finally, simulation results of an aircraft application are presented to illustrate the finite‐time convergence of the proposed fault estimation observer. [ABSTRACT FROM AUTHOR]

In this study, under the directed communication topology, an adaptive observer‐based distributed fault estimation observer (DFEO) is studied with the use of a linear matrix inequality (LMI) for multi‐agent systems. Firstly, for each agent, a corresponding fault estimation observer is constructed based on their relative output estimation errors. To consider DFEO design from an overall perspective, the whole error dynamics is obtained by defining global error vectors. Then an adaptive technique‐based DFEO design is proposed for multi‐agent systems with directed communication topology. Moreover, the proposed design can be represented with LMIs to establish a systematic design procedure. Finally, simulation results are presented to illustrate the effectiveness of the proposed design techniques. [ABSTRACT FROM AUTHOR]

A new fault detection and diagnosis method is developed in this study for a class of singular non‐linear systems via the use of observers with adaptive updating rules. The Lyapunov stability theory is applied to obtain a stable observation error system and to obtain the required adaptive tuning rules for the estimation of the process faults. Based on the fault estimation information, the controller is reconfigured to keep the post‐fault system stable, leading to the active fault tolerant control of the non‐linear singular system. A simulated numerical example is included to demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]