93 results found
Ahmad MI, Jaimoukha IM, Frangos M, Krylov subspace restart scheme for solving large-scale Sylvester equations, American Control Conference, Pages: 5726-5726, ISSN: 0743-1619
The development of efficient interior point methods has greatly enlarged the range of control problems with feasible numerical solution. These methods are nevertheless difficult to solve for large-scale problems. In this paper we suggest the use of a Krylov subspace technique for the efficient low-rank approximate solution to large-scale Sylvester equations. The suggested method is a novel restart scheme which improves further the computation efficiency and storage requirements of the standard Krylov subspace methods for the solution of large-scale Sylvester equations.
Ahmad MI, Benner P, Jaimoukha I, 2016, Krylov subspace methods for model reduction of quadratic-bilinear systems, IET CONTROL THEORY AND APPLICATIONS, Vol: 10, Pages: 2010-2018, ISSN: 1751-8644
Zhang C, Jaimoukha IM, Sevilla FRS, 2016, Fault-Tolerant Observer Design with A Tolerance Measure for Systems with Sensor Failures, American Control Conference (ACC), Publisher: IEEE, Pages: 7523-7528, ISSN: 0743-1619
Liu C, Jaimoukha IM, 2015, The Computation of Full-complexity Polytopic Robust Control Invariant Sets, 54th IEEE Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 6233-6238
Sevilla FRS, Jaimoukha IM, Chaudhuri B, et al., 2015, A Semidefinite Relaxation Procedure for Fault-Tolerant Observer Design, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 60, Pages: 3332-3337, ISSN: 0018-9286
Tahir F, Jaimoukha IM, 2015, Low-Complexity Polytopic Invariant Sets for Linear Systems Subject to Norm-Bounded Uncertainty, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 60, Pages: 1416-1421, ISSN: 0018-9286
Sevilla FRS, Jaimoukha I, Chaudhuri B, et al., 2014, Fault-tolerant control design to enhance damping of inter-area oscillations in power grids, INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Vol: 24, Pages: 1304-1316, ISSN: 1049-8923
Zhang Z, Jaimoukha IM, 2014, On-line fault detection and isolation for linear discrete-time uncertain systems, Automatica, Vol: 50, Pages: 513-518, ISSN: 0005-1098
This work proposes a robust fault detection and isolation (FDI) scheme for linear discrete-time systems subject to faults, bounded additive disturbances and norm-bounded structured uncertainties. FDI is achieved by computing, on-line, upper and lower bounds on the fault signal such that a fault is regarded as having occurred when its upper bound is smaller than zero or lower bound is larger than zero. Linear Matrix Inequality (LMI) optimization techniques are used to obtain the bounds. Furthermore, a subsequent-state-estimation technique, together with an estimation horizon update procedure, is proposed, which allows the on-line FDI process to be repeated in a moving horizon procedure. Theapproach is also extended to solve the fault detection (FD) problem of obtaining lower bounds on the total fault signal energy within the estimation horizon. The scheme gives the best estimates of the fault signals given the information available and is sufficiently flexible to incorporate other information that may be available, such as bounds on the disturbance energy. Thus our scheme is immune to false alarms if the system and disturbance are within the uncertainty description. Moreover, we propose a new robustness result to obtain the bounds, which is an extension of current techniques for handling model uncertainties.Finally, the approach is verified using two numerical examples.
Kiskiras J, Jaimoukha IM, Halikias GD, 2013, An explicit state-space solution to the one-block super-optimal distance problem, MATHEMATICS OF CONTROL SIGNALS AND SYSTEMS, Vol: 25, Pages: 167-196, ISSN: 0932-4194
Segundo Sevilla FR, Jaimoukha IM, Chaudhuri B, et al., 2013, Fault-tolerant Control Design to Enhance Damping of Inter-area Oscillations in Power Grids, International Journal of Robust and Nonlinear Control
In this paper passive and active approaches for the design of fault-tolerant controllers (FTCs) are presented. The FTCs are used to improve the damping of inter-area oscillations in a power grid. The effectiveness of using a combination of local and remote (wide-area) feedback signals is first demonstrated. The challenge is then to guarantee a minimum level of dynamic performance following a loss of remote signals. The designs are based on regional pole-placement using Linear Matrix Inequalities (LMIs). First, a passive FTC is proposed. It is shown that the computation of the controller reduces to the solution of bilinear matrix inequalities. An iterative procedure is then used to design the controller. Next, as an alternative to active, time varying controllers, one for each fault scenario, we propose an approach for the design of a `minimal switching' FTC in which only one controller is designed, but where a simple switch is incorporated into the controller structure. A case study in a linear and nonlinear Nordic equivalent system is presented to show that the closed-loop response using a conventional control (CC) design could deteriorate the performance or even destabilize the system if the remote signals are lost and to demonstrate the effectiveness of the proposed FTC designs.
Tahir F, Jaimoukha IM, 2013, Robust feedback model predictive control of constrained uncertain systems, JOURNAL OF PROCESS CONTROL, Vol: 23, Pages: 189-200, ISSN: 0959-1524
Tahir F, Jaimoukha IM, 2013, Causal state-feedback parameterizations in robust model predictive control, AUTOMATICA, Vol: 49, Pages: 2675-2682, ISSN: 0005-1098
Ahmed S, Jaimoukha IM, 2012, A relaxation-based approach for the orthogonal Procrustes problem with data uncertainties, Pages: 906-911
The orthogonal Procrustes problem (OPP) deals with matrix approximations. The solution of this problem gives an orthogonal matrix to best transform one data matrix to another, in a Frobenius norm sense. In this work, we use semidefinite relaxation (SDR) to find the solutions of different OPP formulations. For the standard problem formulation, this approach yields an exact solution, i.e. no relaxation gap. We also address uncertainties in the data matrices and formulate a min-max robust problem. The robust problem, being non-convex, turns out to be a difficult optimization problem; however, it is relatively straight forward to approximate it into a convex optimization problem using SDR. Our preliminary results on robust problem show that the solution of the relaxed uncertain problem does not guarantee zero relaxation gap, and as a result, we cannot always find a solution, which satisfies the orthogonality constraint. In such cases we use orthogonalization, which gives the nearest orthogonal matrix from the SDR based solution. All these relaxed formulations, can be easily converted into a semidefinite program (SDP), for which polynomial time efficient algorithms exists. For the nominal problems, the presented approach may not be computationally efficient than other existing methods. In this work, our main contribution is to demonstrate that the SDR approach provides a unified framework to solve not only the standard OPP but can also solve the problems with uncertainties in the data matrices, which other existing approaches cannot handle. © 2012 IEEE.
Ahmed S, Kerrigan EC, Jaimoukha IM, 2012, A Semidefinite Relaxation-Based Algorithm for Robust Attitude Estimation, IEEE TRANSACTIONS ON SIGNAL PROCESSING, Vol: 60, Pages: 3942-3952, ISSN: 1053-587X
Li Z, Mazars E, Zhang Z, et al., 2012, State-space solution to the H-/H infinity fault-detection problem, INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Vol: 22, Pages: 282-299, ISSN: 1049-8923
Li Z, Mazars E, Zhang Z, et al., 2012, State–space solution to the ℋ−/ℋ∞ fault-detection problem, International Journal of Robust and Nonlinear Control, Vol: 22, Pages: 282-299
In this paper we give an optimal state–space solution to the ℋ−/ℋ∞ fault-detection (FD) problem for linear time invariant dynamic systems. An optimal ℋ−/ℋ∞ FD filter minimizes the sensitivity of the residual signal to disturbances while maintaining a minimum level of sensitivity to faults. We provide a state–space realization of the optimal filter in an observer form using the solution of a linear matrix inequalities optimization problem. We also show that, through the use of weighting filters, the detection performance can be enhanced and some assumptions can be removed. Two numerical examples are given to illustrate the algorithm.
Mylvaganam T, Fobelets K, Jaimoukha I, 2012, Optimal Design of Nanowire Array Based Thermocouple, 9th European Conference on Thermoelectrics (ECT), Publisher: AMER INST PHYSICS, Pages: 17-20, ISSN: 0094-243X
Sevilla FRS, Jaimoukha I, Chaudhuri B, et al., 2012, Fault-tolerant Wide-area Control for Power Oscillation Damping, General Meeting of the IEEE-Power-and-Energy-Society, Publisher: IEEE, ISSN: 1944-9925
Ahmed S, Kerrigan EC, Jaimoukha IM, 2011, Semidefinite Relaxation of a Robust Static Attitude Determination Problem, 50th IEEE Conference of Decision and Control (CDC)/European Control Conference (ECC), Publisher: IEEE, Pages: 5337-5342
Li Z, Mazars E, Zhang Z, et al., 2011, State–space solution to the H2/Hinfinity fault-detection problem, International Journal of Robust and Nonlinear Control
In this paper we give an optimal state–space solution to the H−/H∞ fault-detection (FD) problem for linear time invariant dynamic systems. An optimal H−/H∞ FD filter minimizes the sensitivity of the residual signal to disturbances while maintaining a minimum level of sensitivity to faults. We providea state–space realization of the optimal filter in an observer form using the solution of a linear matrix inequalities optimization problem. We also show that, through the use of weighting filters, the detectionperformance can be enhanced and some assumptions can be removed. Two numerical examples are given to illustrate the algorithm.
Zhang Z, Jaimoukha IM, 2011, An optimal solution to an H-/H-infinity fault detection problem, 50th IEEE Conference of Decision and Control (CDC)/European Control Conference (ECC), Publisher: IEEE, Pages: 903-908
Ahmad MI, Jaimoukha I, Frangos M, 2010, Krylov Subspace Restart Scheme for Solving Large-Scale Sylvester Equations, American Control Conference, Publisher: IEEE, Pages: 5726-5731, ISSN: 0743-1619
Ahmad MI, Jaimoukha I, Frangos M, 2010, H-2 Optimal Model Reduction of Linear Dynamical Systems, 49th IEEE Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 5368-5371, ISSN: 0743-1546
Zhang Z, Jaimoukha IM, 2010, A measurement analysis approach to online fault detection and isolation for linear discrete-time uncertain systems, 49th IEEE Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 4399-4404, ISSN: 0191-2216
Li Z, Jaimoukha IM, 2009, Observer-based fault detection and isolation filter design for linear time-invariant systems, INTERNATIONAL JOURNAL OF CONTROL, Vol: 82, Pages: 171-182, ISSN: 0020-7179
Li Z, Zolotas A, Jaimoukha I, et al., 2009, Integrated Design of Dynamic Controller with Fault Diagnosis and Tolerance, 17th Mediterranean Conference on Control and Automation, Publisher: IEEE, Pages: 694-699, ISSN: 2325-369X
Zhang Z, Jaimoukha IM, 2009, Fault detection and isolation for linear discrete-time systems using input/output measurement analysis, Joint 48th IEEE Conference on Decision and Control (CDC) / 28th Chinese Control Conference (CCC), Publisher: IEEE, Pages: 4908-4913, ISSN: 0743-1546
Frangos M, Jaimoukha IM, 2008, Adaptive Rational Interpolation: Arnoldi and Lanczos-like Equations, EUROPEAN JOURNAL OF CONTROL, Vol: 14, Pages: 342-354, ISSN: 0947-3580
Mazars E, Jaimoukha IM, Li Z, 2008, Computation of a Reference Model for Robust Fault Detection and Isolation Residual Generation, Journal of Control Science and Engineering, Vol: 2008, Pages: 1-12, ISSN: 1687-5249
Orukpe PE, Zheng X, Jaimoukha IM, et al., 2008, Model predictive control based on mixed H-2/H-infinity control approach for active vibration control of railway vehicles, 20th Symposium of the International-Association-for-Vehicle-System-Dynamics, Publisher: TAYLOR & FRANCIS LTD, Pages: 151-160, ISSN: 0042-3114
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