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This paper presents a new design of hybrid Petri net sliding mode control (PNSMC) applied to reach the maximum power point tracking (MPPT) of a variable speed wind energy conversion system. To solve the main and major undesired phenomenon faced by conventional sliding mode control, the high frequency oscillations known as chattering, the design of a hybrid controller based on Petri network sliding...
This paper addresses the parameter identification problem of a fractional order system with a known structure. Thus, based on the variational iteration method, its shown that the identification of the parameters can be formulated as an optimization problem. The objective function is the L2-norm of the error between the measured and the model outputs, and the unknown model parameters are the decision...
This paper focuses to improve wind turbine systems efficiency, in other words, to maximize the output power delivered by the wind turbine. To do this it is necessary to have a good controller. In this study, we use a nonlinear synergetic controller. Synergetic control theory is applied to reach the maximum power point tracking (MPPT) of a variable speed energy conversion system. A comparison with...
The block oriented structure such as Hammerstein, Wiener, etc… became very popular for the non-linear system modelling due to its simplicity and parsimony. In this paper, fractional hammerstein system is considered; it consists of a static non-linear block followed by a fractional linear dynamical block. The particle swarm optimisation is used to estimate the system parameters as well as the fractional...
Identification of fractional Hammerstein controlled autoregressive systems (HCAR) is considered in this work. This system consists of a memoryless nonlinear sub-system followed by a fractional CAR subsystem. A nonlinear optimization algorithm is developed in order to estimate the system parameters as well as the fractional order. To illustrate the method efficiency, different simulations are performed...
In this paper, sliding mode observers are designed in order to estimate actuator and sensor faults for linear fractional-order systems. The system is represented by a commensurate fractional-order state space model, in the presence of unknown sensor and actuator faults. The convergence of the designed observers is established. A numerical example is given to illustrate the effectiveness of the proposed...
This paper derives an iterative algorithm for identifying a fractional Hammerstein non-linear system. Such system consists of a static non-linear block followed by a linear dynamic part. The proposed approach uses the hierarchical identification principle based on Levenberg-Marquardt algorithm and is able to estimate the parameters of both the linear part and the nonlinear part as well as the fractional...
In this paper, an approach using a new formalism is proposed to analyze the stability of linear discrete-time fractional-order systems. Asymptotic stability of such systems is examined. Practical asymptotic stability is introduced and illustrated by a numerical example.
This report relates the pulse Doppler Weather Radar signal processing field and especially about the estimation of the spectral moments of weather Doppler echoes in severe meteorological situations such as wind shears, tornadoes. This paper will treat the problematics of improving the quality of weather forecasting in order to increase the safety of aviation by proposing a new method based on the...
This paper deals with identification of discrete nonlinear fractional order systems based on wiener models. Such systems consist of a linear dynamic block followed by a static non-linearity; in this study they are described using Polynomial Non Linear State Space(PNLSS) fractional models. Self Adaptive Velocity Particle Swarm Optimization (SAVPSO) is used; it is a modified PSO, which allows the constraints...
Fractional systems are known to model complex dynamics with a reduced number of parameters. This paper deals with identification of discrete fractional order systems based on non-linear Hammerstein models. Such systems consist of a static non-linear block followed by a linear dynamic system. The polynomial non-linear state space equations (PNLSS) are used to represent the fractional Hammerstein system...
In this paper, a novel transmission scheme based on the discrete-time fractional-order chaotic system for private digital communications is proposed. The fractional-order Modified-Henon map is used. By adjusting the fractional-orders appropriately, it has been shown that the fractional-order Modified-Henon system possesses a chaotic behaviour. The exact synchronization based on the delayed observer...
This paper deals with identification of Wiener nonlinear systems. Such systems, consist of a linear dynamic block followed by a static non-linear subsystem. In this work, Polynomial Non Linear State Space(PNLSS) models are used to describe them. An output error identification method is performed, based on Levenberg-Marquardt algorithm; the parameters sensitivity functions are developed as a multivariable...
Fractional systems are known to model complex dynamics with a reduced number of parameters. This paper deals with identification of discrete fractional order systems based on non-linear Hammerstein models. Such systems consist of a static non-linear block followed by a linear dynamic system. The polynomial non-linear state space equations (PNLSS) are used to represent the fractional Hammerstein system...
In this work we propose a novel scheme for adaptive system identification. This scheme is based on a normalized version of the least-mean fourth (LMF) algorithm. In contrast to the LMF algorithm, this new normalized version of the LMF algorithm is found to be independent of the input sequence autocorrelation matrix. It is also found that it converges faster than the normalized least mean square (NLMS)...
The class of LMS algorithms employing a general error nonlinearity is considered. The calculus of variations is employed to obtain the optimum error nonlinearity for an independent and identically distributed input. The nonlinearity represents a unifying view of error nonlinearities in LMS adaptation. In particular, it subsumes two recently developed optimum nonlinearities for arbitrary and Gaussian...
New model-reduction numerical procedure for a class of stable nonlinear systems is proposed. The proposed design is devoted to a spacial class of nonlinear systems whose nonlinearities are not necessarily Lipschitz with respect to its arguments. Additionally, the systems under consideration may contain uncertain parameters, having known lower and upper bounds. The computation of the reduced-model...
Tow different architectures are presented to fuse measurements coming from odometers, compass and accelerometer to locate wheelchair position in 2D Cartesian coordinates, with Extended KALMAN Filter (EKF). The performance of these architectures is checked with simulated data. Detailed mathematical expressions are provided which could be useful for algorithm implementation. Comparative studies between...
This paper presents the application of time weighted model reduction using cross gramians on a state space model derived from two partial differential equations representing the instantaneous thermal balance of a differential element of length along the absorber plate and the absorber plate to fluid heat convection process respectively of a flat plate solar collector. Finite difference method is applied...
This paper presents an overview and the recent advances of the time domain system identification using fractional models. The main methods are presented and commented for the linear, non-linear and multivariable fractional order systems.
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