Search results for "Control theory"
showing 10 items of 1333 documents
PROPAGATING INTERFACES IN A TWO-LAYER BISTABLE NEURAL NETWORK
2006
The dynamics of propagating interfaces in a bistable neural network is investigated. We consider the network composed of two coupled 1D lattices and assume that they interact in a local spatial point (pin contact). The network unit is modeled by the FitzHugh–Nagumo-like system in a bistable oscillator mode. The interfaces describe the transition of the network units from the rest (unexcited) state to the excited state where each unit exhibits periodic sequences of excitation pulses or action potentials. We show how the localized inter-layer interaction provides an "excitatory" or "inhibitory" action to the oscillatory activity. In particular, we describe the interface propagation failure a…
Active disturbance rejection control of linear induction motor
2017
This paper proposes the theoretical framework and the experimental application of the active disturbance rejection control to linear induction motors. Such a nonlinear control (ADRC) technique can be viewed as a particular kind of input-output linearization control, where the nonlinear transformation of the state is not computed by means of the model, but it is estimated online. Such an approach permits to cope with unmodelling dynamics, as well as uncertainty in the knowledge of the model parameters and exogenous disturbances. The effectiveness of the proposed ADRC control law has been verified both by numerical simulations and experimentally on a suitably developed test setup. Moreover, t…
Reciprocal Relationships Between Perceived Supportive School Climate and Self-reported Truancy : A Longitudinal Study from Grade 6 to Grade 9
2022
This longitudinal study of 1,066 Finnish students examined bidirectional reciprocal relationships between changes in perceived supportive school climate and changes in self-reported truancy from the last year of primary school (Grade 6) to the last year of lower secondary school (Grade 9). The results of the random intercept cross-lagged panel model showed, first, that a decrease in positive perceptions of school climate at the previous time point predicted more self-reported truancy at the following time point. Second, an increase in self-reported truancy predicted less positive perceptions of supportive school climate. The study indicates that students’ perceptions of supportive school cl…
Modeling and Backstepping Control of the Electronic Throttle System
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/871674 Open access Electronic throttle is widely used in modern automotive engines. An electronic throttle system regulates the throttle plate angle by using a DC servo motor to adjust the inlet airflow rate of an internal combustion engine. Its application leads to improvements in vehicle drivability, fuel economy, and emissions. In this paper, by taking into account the dynamical behavior of the electronic throttle, the mechanism model is first built, and then the mechanism model is transformed into the state-space model. Based on the s…
Agreement and disagreement between expectations and realizations
1990
The objective of the paper is to measure the intensity of the relation between expectations and realizations for strategic variables of firms, such as production, demand or prices. An anticipation error reveals a disagreement which can be associated with the rational expectations hypothesis. The agreement coefficient between classifications, given by COHEN (1968) and LIGHT (1971) and calculated from a probability matrix, is used to define a direct measure of the disagreement between classifications. Comparison of the coefficients is used to test the rational expectations hypothesis.The coefficients are applied to business survey data of INSEE for France between 1974 and 1986.
Recursive estimators 1
1991
In this paper, we present first the recursive estimation of parameters of linear regression models and we show the link between a matrix of projection and a matrix of gain. Two cases are examined : constant parameters and parameters changing over time. In the second part the recursion formulae for the two stage least squares are given.
Des capacités de choix aux probabilités de choix (un théorème de conversion)
1992
Une partie importante de la théorie des choix discrets concerne les développements du modèle de Luce 1959]. Cette place privilégiée provient sans nul doute de l’extrême élégance de PAxiome du Choix qui permet d’une part, d’introduire une sorte de rationalité imparfaite du comportement en autorisant la construction de probabilités de choix et d’autre part, de décrire un processus de choix qui semble raisonnablement réaliste : en effet, il est suggéré que l’agent faisant face à un ensemble fini d’actions, choisit dans un premier temps un sous-ensemble, puis finalement, à l ’intérieur de ce sous-ensemble, une action. Il existe de nombreuses versions de ce modèle ( Yellot [1977], Strauss [1980]…
La combinaison de prévisions multiples en présence d'objectifs multiples
1989
L'idée de combiner plusieurs prédicteurs pour générer des prévisions combinées plus fiables semble ne dater que de 1969, date de la publication de l'article de Bâtes et Granger (1969). Depuis lors on a constaté un foisonnement de publications tant théoriques qu'empiriques dans ce domaine et l'utilité pratique de la combinaison de prévisions individuelles y a été amplement démontrée.
Stability of stochastic nonlinear systems with state-dependent switching
2013
In this paper, the problem of stability on stochastic systems with state-dependent switching is investigated. To analyze properties of the switched system by means of Itô’s formula and Dynkin’s formula, it is critical to show switching instants being stopping times. When the given active-region set can be replaced by its interior, the local solution of the switched system is constructed by defining a series of stopping times as switching instants, and the criteria on global existence and stability of solution are presented by Lyapunov approach. For the case where the active-region set can not be replaced by its interior, the switched systems do not necessarily have solutions, thereby quasi-…
Towards Robust Adaptive Least-Squares Parameter Estimation with Internal Feedback
1998
Abstract The new concepts of the ‘covariance matrix normalization’ and the ‘cascade’ structure of the adaptive least-squares estimator are shown to generalize and extend the use of internal information feedback in various robustness/alertness-oriented modifications to the standard ALS estimation algorithm. In the cascade estimation structure it is possible to ‘naturally’ stabilize, rather than maximize, the information matrix so that the covariance windup and blowup are effectively eliminated and the celebrated square root update of the covariance matrix is no longer needed Consequently, a new, ‘single-loop/cascade’ ALS MIMO estimation algorithm, enabling to effectively track both slow and …