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scientific edition of Bauman MSTUSCIENCE & EDUCATIONBauman Moscow State Technical University. El № FS 77 - 48211. ISSN 1994-0408
Identification of Nonlinear Dynamical Systems with the Specified Nonlinearity Types in Hodographs
# 10, October 2014 DOI: 10.7463/1014.0727229
Article file:
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This work concerns the problem of identification of nonlinear dynamic systems from the experimental data obtained by applying test signals to the system. The goal is to determinate the coefficients of differential equations of systems by the experimental frequency hodographs and separation of similar, but different in essence forces: dissipative forces of the first derivative in the motion equations and dissipative action force of dry friction. It was suggested to use the harmonic linearization method and to approximate the nonlinearity of "dry friction" by linear friction with the corresponding harmonic linearization coefficient. It was assumed that the frequency transfer function of the identified system is a well-known value. It was also assumed that there are disturbances while obtaining frequency characteristics of the real-world system. As a result, the points of experimentally obtained hodograph move randomly. A solution of the identification problem was searched in the hodograph class, specified by the system model, which had the same form of the frequency transfer function as a form of the frequency transfer function of the system identified. Searching for the unknown coefficients of the frequency transfer function of the system model was carried out by minimizing a criterion (measure) of proximity of the experimentally obtained hodograph system, which was previously described and published by one of the authors, and the system hodograph model for all the experimental points. A solution of the nonlinear dynamic system identification in frequency hodograph was reduced to solving an equations system, linear relative to the unknown parameters of the frequency transfer function of the system model. For the second-order dynamic system with combination of nonlinearity of the type "dry friction" and linear friction was developed the simulation software to provide pseudo experimental data of random accuracy and determine parameters of this system. A computational experiment of accuracy evaluation was made with which the proposed algorithm determines the parameters of the system. Illustrative numerical simulation has demonstrated that the accuracy of determining the values of the coefficients transfer function does not exceed the range of measurement accuracy of experimental samples of this system hodograph. This method of the identification of nonlinear dynamic systems is not mentioned in the well-known publications. The identification method of nonlinear dynamical systems, described in the article, can be used to determine the parameters of a variety of power actuators. Using the method of harmonic linearization and identification of dynamical systems hodographs is promising for solving the problem of the identification of nonlinear systems with different types of nonlinearities. References
Publications with keywords: identification, harmonic linearization, nonlinear dynamical system, dry friction, frequency locus, linear friction Publications with words: identification, harmonic linearization, nonlinear dynamical system, dry friction, frequency locus, linear friction See also: Thematic rubrics: Поделиться:
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