scholarly journals An algorithm using genetic programming for the compensation of nonlinear distortion based on wiener system model

2004 ◽  
Vol 17 (2) ◽  
pp. 219-229
Author(s):  
Changsong Xie ◽  
Li Xuhui
Keyword(s):  
Genetic Programming ◽  
Nonlinear Distortion ◽  
Linear Time ◽  
Iteration Algorithm ◽  
Wiener Model ◽  
Distortion Compensation ◽  
Object System ◽  
Linear Time Invariant ◽  
Wiener System ◽  
Time Invariant

In this paper we presented an iteration algorithm using genetic programming (GP) to get the Wiener model of a nonlinear system and then to compensate the nonlinear distortion. The GP is used to identify the linear time-invariant (LTI) part and memory less nonlinear (MLNL) part of the Wiener model of the object system. By means of iteration, the identification precision will be improved gradually with the iteration steps. In order to compensate the non linearity a distortion compensation function (DCF) will be estimated also by means of GP. If the object system can be well described using Wiener model, this algorithm converges. The experiment results show that the compensation precision is fairly high.

Signal Distortion Compensation of Linear Time-Invariant Measurement System

2000 ◽  
Author(s):  
Changting Wang ◽  
Robert X. Gao
Keyword(s):  
Measurement System ◽  
Precision Measurement ◽  
Linear Time ◽  
Signal Distortion ◽  
Charge Amplifier ◽  
Distortion Compensation ◽  
Linear Time Invariant ◽  
Lti System ◽  
Invariant Measurement ◽  
Time Invariant

Abstract Non-distortion is an important aspect in precision measurement, calibration and signal processing. In this paper, the distortion error of a linear time-invariant measurement system is derived for periodical and non-periodical signal inputs, using Fourier Series and Fourier Transformation. The signal distortion is measured by the error-to-signal energy ratio. A charge amplifier circuit has been analyzed as an example, which shows that the distortion of an LTI system can not be simply neglected if precision measurement is required. Direct compensation and adaptive control methods have been discussed to reduce the LTI system distortion. The applications of these two methods to the charge amplifier design are discussed, which demonstrated good results.

Evaluation of fractional order of the discrete integrator. Part II

2020 ◽  
Vol 23 (2) ◽  
pp. 408-426
Author(s):  
Piotr Ostalczyk ◽  
Marcin Bąkała ◽  
Jacek Nowakowski ◽  
Dominik Sankowski
Keyword(s):  
Fractional Order ◽  
Output Signal ◽  
Linear Time ◽  
Mathematical Problem ◽  
Simple Method ◽  
Linear Time Invariant ◽  
Input And Output ◽  
Order Difference Equation ◽  
Time Invariant ◽  
Discrete Integrator

AbstractThis is a continuation (Part II) of our previous paper [19]. In this paper we present a simple method of the fractional-order value calculation of the fractional-order discrete integration element. We assume that the input and output signals are known. The linear time-invariant fractional-order difference equation is reduced to the polynomial in a variable ν with coefficients depending on the measured input and output signal values. One should solve linear algebraic equation or find roots of a polynomial. This simple mathematical problem complicates when the measured output signal contains a noise. Then, the polynomial roots are unsettled because they are very sensitive to coefficients variability. In the paper we show that the discrete integrator fractional-order is very stiff due to the degree of the polynomial. The minimal number of samples guaranteeing the correct order is evaluated. The investigations are supported by a numerical example.

Design and implementation of decoupled periodic control scheme for a laboratory-based quadruple-tank process

2021 ◽  
pp. 095965182110228
Author(s):  
Jatin K Pradhan ◽  
Arun Ghosh
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Linear Time ◽  
Disturbance Attenuation ◽  
Minimum Phase ◽  
Periodic Control ◽  
Linear Time Invariant ◽  
Control Scheme ◽  
Gain Margin ◽  
Time Invariant

It is well known that linear time-invariant controllers fail to provide desired robustness margins (e.g. gain margin, phase margin) for plants with non-minimum phase zeros. Attempts have been made in literature to alleviate this problem using high-frequency periodic controllers. But because of high frequency in nature, real-time implementation of these controllers is very challenging. In fact, no practical applications of such controllers for multivariable plants have been reported in literature till date. This article considers a laboratory-based, two-input–two-output, quadruple-tank process with a non-minimum phase zero for real-time implementation of the above periodic controller. To design the controller, first, a minimal pre-compensator is used to decouple the plant in open loop. Then the resulting single-input–single-output units are compensated using periodic controllers. It is shown through simulations and real-time experiments that owing to arbitrary loop-zero placement capability of periodic controllers, the above decoupled periodic control scheme provides much improved robustness against multi-channel output gain variations as compared to its linear time-invariant counterpart. It is also shown that in spite of this improved robustness, the nominal performances such as tracking and disturbance attenuation remain almost the same. A comparison with [Formula: see text]-linear time-invariant controllers is also carried out to show superiority of the proposed scheme.

scholarly journals Differential-algebraic systems are generically controllable and stabilizable

2021 ◽  
Author(s):  
Achim Ilchmann ◽  
Jonas Kirchhoff
Keyword(s):  
Algebraic Geometry ◽  
Linear Time ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Algebraic Systems ◽  
Linear Time Invariant ◽  
Survey Article ◽  
Link Type ◽  
Invariant Differential ◽  
Time Invariant

AbstractWe investigate genericity of various controllability and stabilizability concepts of linear, time-invariant differential-algebraic systems. Based on well-known algebraic characterizations of these concepts (see the survey article by Berger and Reis (in: Ilchmann A, Reis T (eds) Surveys in differential-algebraic equations I, Differential-Algebraic Equations Forum, Springer, Berlin, pp 1–61. 10.1007/978-3-642-34928-7_1)), we use tools from algebraic geometry to characterize genericity of controllability and stabilizability in terms of matrix formats.

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