Nonlinear System

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Genetic Algorithm Approach for Controlling Nonlinear System

Genetic Algorithm Approach for Controlling Nonlinear System

smaller between the fuzzy model and practical system model, we should employ some nonlinear functions in the local model. The control problem of this class of systems is more difficult than that of the linear form. The T–S fuzzy time- delay systems were investigated, and the memorial switching controllers were successfully constructed [15], [16]. Since the discontinuous control schemes not only induce the problems of the existence and uniqueness of solutions but may also cause the chattering phenomena and excite the high frequency phenomena; therefore, we should try to employ the smooth controller in practical systems if possible. On the other hand, memorial the controller needs a large controller memory to store a large amount of past information, and the precise delay information must be available for controller implementation. In practical systems, a controller equipped with a large memory is costly, and the precise delay time is difficult to obtain, especially when it is time varying. In view of these observations, we aim to design the continuous and memory less state feedback controllers for nonlinear time-delay systems. We use a set of fuzzy rules to describe a global nonlinear system into a set of local time-delay systems with uncertain nonlinear functions.
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Filter for detecting and isolating faults for a nonlinear system

Filter for detecting and isolating faults for a nonlinear system

This paper extends the approach proposed by Liu and Si (1997) to non-linear systems with unmeasured inputs and multiple faults using state-dependent coefficient parametrization. This methodology transfers the nonlinear system into a quasi linear structure. Then, the columns of the fault detectability matrix are assigned as an eigenvectors of the filter’s transition matrix and the remaining freedom of design is used to fix the dynamics of the filter. If there is noise, they are used to minimise its effect on the generated residuals. The proposed strategy can also be applied in the presence of unknown inputs or disturbances robustifying the detection and isolation of multiple faults. The obtained fault isolation filter is very similar to the predictor-corrector structure of the filters for nonlinear systems.
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Model Reduction of a Perturbative Representation of a Weakly Nonlinear System

Model Reduction of a Perturbative Representation of a Weakly Nonlinear System

It is evident from (11) that the scale invariance property does not hold. To enable application of linear theory to (6) would require that B u → α B u which is not the case as evident from (11). Consequently, linear model reduction techniques may not be applied directly to the perturbative representation and hence, a modification is required. To this end, a parameter µ is introduced with a view to explicitly accounting for the scale dependence of the nonlinear system. The role of µ is to bear the nonlinear properties of the system throughout the reduction process. Consider (6) and (7). The B u term can be rewritten as:
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Biomolecular implementation of nonlinear system theoretic operators

Biomolecular implementation of nonlinear system theoretic operators

We have presented results on how abstract chemical re- actions can be used to implement a number of nonlinear system theoretic operators such as multivariate polynomi- als, rational functions, and Hill-type nonlinearities. These results extend the architecture established for linear dynamic systems in [19]. We have shown how a combination of three elementary abstract idealised reactions, viz., catalysis, annihilation, and degradation can be used to realize these functions and have translated these chemical reactions into enzyme-free, entropy-driven DNA reactions. We have illus- trated these results through three applications: (1) the Stan- Sepulchre oscillator, (2) computation of the ratio of two biomolecular signals and polynomials, and (3) regulation of a static nonlinear plant using a PI+anti-windup controller. We intend to follow the approach of [10], which uses [17], [27]-[29], to obtain the DNA strand displacement, genelet, and DNA Toolbox implementations of the results derived in this manuscript.
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Controlling Of Nonlinear System by Using Fuzzy Logic Controller

Controlling Of Nonlinear System by Using Fuzzy Logic Controller

In this paper a new optimization method named Fuzzy logic controller is used to solve the problem of controller design for nonlinear systems. As an optimizer, Fuzzy logic controller is used to achieve accurate model, and then it is adopted to obtain offline PID controller. Fuzzy logic controller is used to tune the parameters of PID controller in order to get good performance and also to control the nonlinear system. Fuzzy with PID provides better optimization when compared to other optimizations. This optimization maximises the efficiency of production. By comparison with STA, GA and PSO it is found that Fuzzy PID is more stable. With regard to convergence rate, it is also discovered that Fuzzy PID is much faster than its competitors.
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A tensor trust region model for nonlinear system

A tensor trust region model for nonlinear system

where S : n → n is continuously differentiable nonlinear system. The nonlinear system (1.1) has been proved to possess wildly different application fields in parameter estimating, function approximating, and nonlinear fitting, etc. At present, there exist many effective algorithms working in it, such as the traditional Gauss–Newton method [1, 9–11, 14, 16], the BFGS method [8, 23, 27, 29, 39, 43], the Levenberg–Marquardt method [6, 24, 42], the trust-region method [4, 26, 35, 41], the conjugate gradient algorithm [12, 25, 30, 38, 40], and the limited BFGS method [13, 28]. Here and in the next statement, for research convenience, suppose that S(x) has solution x ∗ . Setting β(x) := 1
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Nonlinear system identification of the filling phase of a wet clutch system

Nonlinear system identification of the filling phase of a wet clutch system

The work presented illustrates how the choice of input perturbation signal and experimental design improves the derived model of a nonlinear system, in partic- ular the dynamics of a wet-clutch system. The relationship between the applied input current signal and resulting output pressure in the filling phase of the clutch is established based on bandlimited periodic signals applied at different current operating points and signals approximating the desired filling current signal. A polynomial nonlinear state space model is estimated and validated over a range of measurements and yields better fits over a linear model, while the performance of either model depends on the perturbation signal used for model estimation. Keywords: Experiment design, Input signals, Clutches, Nonlinear system, Frequency response, State space
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Index Terms homogeneous nonlinear system, asymptotical stability, nonlinear eigenvalue.

Index Terms homogeneous nonlinear system, asymptotical stability, nonlinear eigenvalue.

Abstract— The Lyapunov’s second method for the stability analysis of nonlinear dynamic systems requires finding Lyapunov functions. Unfortunately, finding a suitable Lyapunov function is a tedious process for a given complex nonlinear system if it is not impossible. On the other hand there are several algebraic approaches like the eigenvalue method for analyzing or designing linear time invariant systems. In this paper, we develop the eigenvalue method for the stability analysis of extended homogeneous nonlinear systems. In the case of polynomial homogeneous systems of zero degree it is shown that the zero equilibrium state of system is globally asymptotically stable if and only if all the homogeneous eigenvalues have negative real parts. Ultimately, an example is presented to describe the approach.
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On the orthogonalised reverse path method for nonlinear system identification

On the orthogonalised reverse path method for nonlinear system identification

Abstract. The problem of obtaining the underlying linear dynamic compliance matrix in the presence of nonlinearities in a general Multi-Degree-of-Freedom (MDOF) system can be solved using the Conditioned Reverse Path (CRP) method introduced by Richards and Singh (1998 Journal of Sound and Vibration, 213(4): p. 673-708). The CRP method also provides a means of identifying the coefficients of any nonlinear terms which can be specified a priori in the candidate equations of motion. Although the CRP has proved extremely useful in the context of nonlinear system identification, it has a number of small issues associated with it. One of these issues is the fact that the nonlinear coefficients are actually returned in the form of spectra which need to be averaged over frequency in order to generate parameter estimates. The parameter spectra are typically polluted by artefacts from the identification of the underlying linear system which manifest themselves at the resonance and anti-resonance frequencies. A further problem is associated with the fact that the parameter estimates are extracted in a recursive fashion which leads to an accumulation of errors. The first minor objective of this paper is to suggest ways to alleviate these problems without major modification to the algorithm. The results are demonstrated on numerically-simulated responses from MDOF systems. In the second part of the paper, a more radical suggestion is made, to replace the conditioned spectral analysis (which is the basis of the CRP method) with an alternative time domain decorrelation method. The suggested approach – the Orthogonalised Reverse Path (ORP) method – is illustrated here using data from simulated Single-Degree-of-Freedom (SDOF) and MDOF systems.
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Nonlinear System Identification in Frequent and Infrequent Operating Points for Nonlinear Model Predictive Control

Nonlinear System Identification in Frequent and Infrequent Operating Points for Nonlinear Model Predictive Control

Despite of the fact that most of industrial processes are nonlinear in nature, many applications of MPC so far have been applied to linear models [3]. However, there exist processes whose nonlinearities are severe enough not to be negligible. Accordingly, nonlinear model predictive control, NMPC which uses a nonlinear model in MPC strategy is very helpful and justifiable [14]. In nonlinear modeling, it is possible to use neural models, fuzzy models, a combination of both or other nonlinear models such as Wiener and Hammerstein models. In this paper, multilayer perceptron (MLP) neural network is selected as the process model.
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Nonlinear system identification

Nonlinear system identification

Ziegler, 11/93 function [xshort,xdot]=cent2x,dt; [NP,MP]=sizex; %disp['Calculating the derivative to second order accuracy.'] xdot=zerosNP-2,MP; xdotl :NP-2,:=x3 :NP,:-xl :NP-2,: 72*dt; [r]

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Nonlinear system identification and prediction

Nonlinear system identification and prediction

a MATLAB program written to encapsualte all the programs at It's basic function is to % 17 reconstruct a given [coef,q,qd]=reconX,dt,delay,dim, points function [coef,q,qd]=reconX,dt,dela[r]

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Steady state response of a nonlinear system

Steady state response of a nonlinear system

to a given input is first obtained in the form of a series solution in the multidimensional frequency domain.. series solution will converge..[r]

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A New Method for a Nonlinear Acoustic Echo Cancellation System

A New Method for a Nonlinear Acoustic Echo Cancellation System

Abstract - Acoustic echo cancellation (AEC) is a fundamental requirement of signal processing to increase the quality of teleconferences. AEC has been concerned since the 1950s in telecommunications and efficient solutions for linear echo cancellation had been devised. Teleconferencing systems employ FIR adaptive filter to echo cancellation. However, in this case the problem is difficult to solve because of nonlinear echo path. In this paper, we propose a new method for acoustic echo cancellation system which uses neural network combined with Laguerre filter model to reduce echo signal in nonlinear system. The results of simulations on Simulink will demonstrate the efficiency of the solution.
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An Adaptive Nonlinear Filter for System Identification

An Adaptive Nonlinear Filter for System Identification

In nonlinear system identification, input signals with high eigen value spread, ill-conditioned tap input autocorre- lation matrix can lead to divergence or poor performance of a fixed step-size adaptive algorithm. To mitigate this problem, a number of variable step-size update algorithms have been proposed. These variable step-size update algorithms can be roughly divided into gradient adaptive step-size [21, 22] and normalized generalized gradient descent [23]. The major limitation of gradient adaptive step-size algorithms is their sensitivity to the time correlation between input signal samples and the value of the additional step-size parameter that governs the gradient adaptation of the step-size. As a result of these limitations, a criteria for the choice of the step-size based on Lyapunov stability theory is proposed to track the optimal step-size required to maintain a fast convergence rate and low misadjust- ment.
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A Equation and Its Connections to Nonlinear Integrable System

A Equation and Its Connections to Nonlinear Integrable System

A large class of exact Equations to A-Equation was found in this work. Tech- niques used in our approach include non-linear transformation between coeffi- cient of a polynomial and its zero, constants of motion, and an interesting inte- grating factor method. The nonlinear system studied here is of interest not only for its connection to inverse problems. It represents a larger category of integra- ble system than C-integrable system and is worth further investigation.

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Controller Design For Nonlinear Motorized Prosthetic Hand System

Controller Design For Nonlinear Motorized Prosthetic Hand System

In spite of the fact that the fuzzy tenets appear like extremely basic, despite everything it can give a superior outcome particularly in considering the best getting a handle on framework since it can give a general picture just by picking the fitting enrollment work [6]. Various specialists likewise have announced that simulated control, for example, Fuzzy logic, hereditary calculation, neural system and neurofuzzy control have been connected in numerous applications. Its application zone is wide in light of the fact that the fundamental shape for all summon sorts of controller comprises of info fuzzy govern base, surmising, fuzzification and yield defuzzification [7].
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Jarratt Second Order Method System of Nonlinear Equations

Jarratt Second Order Method System of Nonlinear Equations

Due to the fact that systems of nonlinear equations arise frequently in science and engineering they have attracted researcher's interest. For example, nonlinear systems of equations, after the necessary processing step of implicit discretization, are solved by finding the solutions of systems of equations. We consider here the problem of finding a real zero, x*= (x* 1 , x* 2 …….; x* n )

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About Solutions of Nonlinear Algebraic System with Two Variables

About Solutions of Nonlinear Algebraic System with Two Variables

intersect if and only if KerR ( A ( λ 0 ), B ( λ o )) ≠ { } θ . As operators A ( , ), ( , ) λ µ B λ µ act in finite-dimensional spaces this common point of their spectra can be only common eigen value of these bundles. The last means, that the two parameter system (2) has an eigen value ( λ 0 , µ 0 ( λ 0 )) . If

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The Solvability of a New System of Nonlinear Variational-Like Inclusions

The Solvability of a New System of Nonlinear Variational-Like Inclusions

We introduce and study a new system of nonlinear variational-like inclusions involving s- G, η - maximal monotone operators, strongly monotone operators, η-strongly monotone operators, relaxed monotone operators, cocoercive operators, λ, ξ-relaxed cocoercive operators, ζ, ϕ, - g-relaxed cocoercive operators and relaxed Lipschitz operators in Hilbert spaces. By using the resolvent operator technique associated with s-G, η-maximal monotone operators and Banach contraction principle, we demonstrate the existence and uniqueness of solution for the system of nonlinear variational-like inclusions. The results presented in the paper improve and extend some known results in the literature.
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