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A generalized blind equalization scheme, insensitive to phase shifts introduced by the channel and small carrier phase offsets, is derived. Multiple constraints optimization techniques have been used in the development of the proposed algorithm. This scheme is an improved version of a dual mode modified constant modulus algorithm (MCMA). It uses the principle of minimal disturbance to induce robustness...
Two classes of fixed polarity linearly independent arithmetic transforms (FPQLIA) for quaternary functions are introduced in this paper. These transforms are Kronecker-based and therefore can be calculated efficiently by fast transforms. Their basic definitions and fast flow graphs are shown. Relations between the different FPQLIA transforms are also presented and an algorithm for the optimization...
This paper presents a novel output-based, discrete-time, sliding mode controller design methodology Output based controllers with and without disturbance estimation are presented. First several existing discrete-time reaching conditions are analyzed and compared. From these methods the linear reaching law is selected to form the basis for the output-based controller design.
We study the stability of the origin for the dynamical system x(t) = u(t)Ax(t) + (1 − u(t))Bx(t), where A and B are two 2×2 real matrices with eigenvalues having strictly negative real part, x ∊ R2 and u(.) : [0, ∞[→ [0,1] is a completely random measurable function. More precisely, we find a (coordinates invariant) necessary and sufficient condition on A and B for the origin to be asymptotically stable...
The aim of this work is to investigate the structure of time-optimal trajectories for a control system modelizing a satellite with two rotors attached along its two fixed axes. Our results extend to the general case those obtained by Sussmann and Tang in an unpublished paper where they treat a particular case described below. We end up finding a sufficient family of four parameters trajectory types...
This paper proposes an implementation for switching median filters using counter propagation networks. The proposed filter consists of an impulse detector based on the counter propagation networks and a median filter. The median filter only removes the impulsive noise marked by the impulse detector and isn't applied to the other pixels. By using the proposed method, we can achieve to reduce the impulsive...
This paper considers linear systems with bounded disturbances, that are not necessarily matched. A static output feedback sliding mode controller is designed. The existence problem is solved by determining a sliding surface that minimizes the ultimate bound of the reduced-order dynamics in the presence of unmatched disturbances. Linear Matrix Inequalities (LMIs) are derived to compute the sliding...
The paper consider some special topics related to controllability of linear switching systems. Consequences of the normal controllability property and controllability under sampling are investigated. Both problems are related to the existence of a finite switching sequence with certain properties. It is shown that completely controllable linear switching systems, regardless to the sign of the allowed...
This paper considers the impulsive-smooth behavior of a switched system interconnection described by the first-order kernel representation. The switched interconnection consists of past and future trajectories which are switched at a certain instant by an external switching mechanism. We derive necessary and sufficient conditions for the concatenability of the past and future behaviors both in the...
This paper deals with hybrid observer design for a class of switched systems. The latter are described by Timed Differential Petri Nets (TDPN) that are characterized by a dwell time ensuring the stability of the considered system. The observer structure is composed of a discrete observer and a continuous observer that are in interaction. The discrete observer reconstructs the discrete mode, by estimating...
This paper attempts to provide a tutorial mode presentation of a time-optimal transfer problem in the geometric framework. The control objective is to change both the orientation and position of a ball sandwiched between two plates in minimum time. The lower plate is fixed and the upper plate can be actuated in two lateral directions. In the geometric framework, the problem of time-optimal reorientation...
In this paper Principal Components Analysis (PCA) is used for detecting faults in a plant with multiple operation modes. PCA reduces the dimensionality of the original historical data by projecting it onto a lower dimensionality space. It obtains the principal causes of variability in a process. If some of these causes change, it can be due to a fault in the process. The classical PCA approach confuses...
In this paper we define the second variation at a bang-bang trajectory as the one of the sub-problem obtained by moving the switching times. Under a suitable regularity condition on the Hamiltonian we give an algorithm to test the positivity of the second variation, complete proofs will be contained in a forthcoming paper [2].
We consider a variant of the time-optimal control of the acrobot and term it sub time-optimal. By exploiting the partially linearized structure obtained through a feedback linearization technique, we swing up the first link to the vertically upright position in optimal time and then stabilize the second link around its vertical equilibrium position. Rate constraints are imposed on the actuator and...
This paper develops some new results on semistability and asymptotic stability of switched systems using multiple Lyapunov functions. The main results of the paper involve sufficient conditions for guaranteeing semistability and asymptotic stability of switched systems using multiple Lyapunov functions and a class of switching conditions. Moreover, converse Lyapunov theorems for a finite family of...
The paper consider some special topics related to controllability and stabilizability of linear switching systems. While providing a short overview on the most important facts related to the topic it is shown how fundamental role is played by the finite switching property in obtaining the controllability and stabilizability results. The paper tries to present some aspects that remain hidden in the...
In this paper, a disturbance attenuation problem for a class of hybrid control systems is posed when the switching from a vector field (also called mode) to another is controlled. Using the equivalence between this problem and a linear-quadratic differential game with piecewise deterministic dynamics, a solution is proposed to this problem.
An operational analysis of a multilevel active front end rectifier, which has the mitigating capability of the current harmonics generated by the nonlinear loads connected to the same power distribution bus would be presented in this paper. Undesirable conditions in the power network such as voltage unbalances and spikes can affect negatively on the operation of very sensitive electric devices. Thus...
This paper presents a model predictive control method applied to a single phase grid-connected inverter. The method uses a discrete-time model of the system to predict the future value of the load current by using all possible voltage vectors generated by the inverter. The voltage vector which minimizes a quality function is selected. Then, use the switch state deduced by the select voltage vector...
In this paper, a novel predictive direct power control (PDPC) strategy is proposed for three-phase AC/DC converters, which is based on a straightforward regulation of instantaneous active and reactive power. The converter controlled by the proposed strategy realizes operations without line-side voltage sensors by introducing the virtual flux (VF) concept and a grid voltage estimation method based...
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