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Isolation Scheme (isolation + scheme)
Selected AbstractsSensor fault detection and isolation for nonlinear systems based on a sliding mode observerINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8-9 2007Xing-Gang Yan Abstract In this paper, a sensor fault detection and isolation scheme for nonlinear systems is considered. A nonlinear diffeomorphism is introduced to explore the system structure and a simple filter is presented to ,transform' the sensor fault into a pseudo-actuator fault scenario. A sliding mode observer is designed to reconstruct the sensor fault precisely if the system does not experience any uncertainty, and to estimate the sensor fault when uncertainty exists. The reconstruction and estimation signals are based only on available information and thus can be implemented online. Finally, a mass,spring system is used to illustrate the approach. Copyright © 2007 John Wiley & Sons, Ltd. [source] A stability guaranteed active fault-tolerant control system against actuator failuresINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2004Midori Maki Abstract In this paper, a new strategy for fault-tolerant control system design has been proposed using multiple controllers. The design of such controllers is shown to be unique in the sense that the resulting control system neither suffers from the problem of conservativeness of conventional passive fault-tolerant control nor from the risk of instability associated with active fault-tolerant control in case that an incorrect fault detection and isolation decision is made. In other words, the stability of the closed-loop system is always ensured regardless of the decision made by the fault detection and isolation scheme. A correct decision will further lead to optimal performance of the closed-loop system. This paper deals with the conflicting requirements among stability, redundancy, and graceful degradation in performance for fault-tolerant control systems by using robust control techniques. A detailed design procedure has been presented with consideration of parameter uncertainties. Both total and partial actuator failures have been considered. This new control strategy has been demonstrated by controlling a McDonnell F-4C airplane in the lateral-direction through simulation. Copyright © 2004 John Wiley & Sons, Ltd. [source] Adaptive TRX isolation scheme by using TX leakage canceller at variable frequencyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2008Jin-Woo Jung Abstract This article presents a TX leakage cancellation scheme for UHF RFID readers. A prototype is implemented on a UHF RFID reader board, which includes a circulator, directional coupler, microcontrol unit (MCU)-controlled variable attenuator, and phase shifter. The difference between a conventional TX leakage canceller and this new one is that, reflected signals caused by mismatches between the front-end and the antenna are included; in addition, high isolation is supplemented at variable frequencies. About 10% of the frequency range is recovered by the best suited parameter values that provide a predetermined process of MCU; and thus, peak isolation characteristics are constantly guaranteed at each center frequency by phase-shifted signal generation that follows references stored in MCU. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2043,2045, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23592 [source] Robust disturbance attenuation for discrete-time active fault tolerant control systems with uncertaintiesOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 2 2003Peng Shi Abstract The problems of stochastic stability and stochastic disturbance attenuation for a class of linear discrete-time systems are considered in this paper. The system under study is a state space model possessing two Markovian jump parameters: one is failure process and another is failure detection and isolation scheme. A controller is designed to guarantee the stochastic stability and a disturbance attenuation level. Robustness problems for the above system with norm-bounded parameter uncertainties are also investigated. It is shown that the uncertain system can be robustly stochastically stabilized and have a robust disturbance attenuation level for all admissible perturbations if a set of coupled Riccati inequalities has solutions. A numerical example is given to show the potential of the proposed technique. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||