The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, we present a multiple-model based method of analyzing for the longitudinal controller performance loss caused by actuator faults in the aircraft elevator system. More specifically, we consider the effects of the failure-induced elevator actuator bandwidth reduction integrated with the longitudinal flight dynamics. Results of the proposed multiple-model based fault detection, isolation,...
This paper addresses a multiple-model based lateral imbalance detection methodology for an uninhabited air vehicle (UAV). Two critical imbalance failures are considered that are the failure-induced left aileron stuck and the centre-of-gravity shift along the y-axis. A bank of LTI Kalman filters are designed to detect the above lateral failures and a flight control law based on the model predictive...
We present a case study designed to highlight some of the practical issues that can arise when using linear robustness analysis techniques such as the structured singular value mu to analyse the robustness of uncertain nonlinear systems. The problem considered in the case study is the familiar ball and beam position control task, where the mass of the ball and the time-delay in the beam actuator are...
We propose a novel approach for computing lower bounds on robust stability or performance for nonlinear systems subject to time-invariant and/or time-varying uncertainty. The approach exploits the binary coding mechanism used in defining chromosomes for evolutionary search algorithms, in order to allow the uncertain parameter space to be searched over time, thus allowing the computation of destabilising...
We demonstrate, using Monte-Carlo simulations, the robust performance of the adaptive control methodology denoted by RMMAC/XI introduced and discussed (Fekri and Athans, 2006 and 2005). The RMMAC/XI architecture can handle simultaneous time-variations in the plant uncertain parameters as well as the disturbance intensity statistics. We compare the RMMAC/XI performance vs that of the best possible...
We demonstrate, using Monte-Carlo simulations, the superior performance of the "Robust Multiple- Model Adaptive Control (RMMAC)" method for different time-varying uncertain parameter waveforms, performance bandwidths and constant disturbance intensities using the test example designed and studied in Refs. [1] and [2]. We further show that the RMMAC RMS performance is just about 10-16% worse...
We use a non-trivial MIMO three-cart Mass-Spring-Dashpot (MSD) system to demonstrate how performance (disturbance-rejection) is reduced as the level of uncertainty in one or two real parameters is increased in the presence of unmodeled dynamics. All designs are carried out by the mixed-mu robust synthesis methodology. Comparisons are made: (a) in the frequency-domain, (b) by RMS values of key signals...
We use the RMMAC architecture and design methodology, introduced in the work of M. Athans et al. (2005) and S. Fekri et al. (2004), to design and evaluate a truly multivariable adaptive control system; this fills a void that is present in the literature. A three-cart problem with two uncertain parameters, two controls, and two outputs is used as the case study. We show that the RMMAC significantly...
The purpose of this research is to study the robust feedback control of a mass-spring system with two masses and two springs. The main performance objective is to keep constant the displacement of the mass affected by a disturbance. Compensators designed by the mu-synthesis method allow us to study how the performance changes with the stiffness constant uncertainly, when the bandwidth of disturbance...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.