Corresponding author: Filimonov Nikolay B., Professor, D. Sc., Moscow State University named after Lomonosov, Moscow, 119991, Russian Federation, e-mail: nbfilimonov@mail.ru

Received on April 20, 2015
Accepted April 27, 2015

The functional purpose of the correcting links in the structure of the automatic regulation systems (ARS) is improvement of the precision and dynamic quality of the regulation processes. In the classical methods of ARS design two types of the correcting links are used: of the sequential and parallel feedback. At the same time there is one more type of correction. It has been insufficiently studied within the framework of the classical automatic regulation theory and practically ignored in the modern researches. It is a parallel feedforward correction (PFC). A logical question appears concerning the usefulness of the given type of correction for the developers of ARS. This question is exactly the subject of the given paper. Three methods of PFC application are considered: compensation of the transfer poles of the control channel, its control by the transfer zeroes, and correction of the amplitude-phase characteristics of an open loop. The method of compensation of the transfer poles of an object reduces the order of the transfer functions of the control channel, and, as a result, the dimension of the regulation problem to be solved is reduced. Its auxiliary effect is analyzed, that is formation of a non-control and non-observed subsystem in ARS structure, the spectrum of which coincides with that of the compensated poles. "The bad" transfer zeroes of an object are problematical for a great many methods of synthesis of ARS. The right zeroes, and also the left zeroes, which are in the immediate proximity to the imaginary axis, are among them. By means of PFC it is possible to change purposefully the transfer zeroes and even to exclude them from the corrected control channel. Correction of the frequency characteristics of the direct chain of PFC is realized with a view to ensure the desired phase and amplitude stability for the closed system. The authors demonstrate good prospects of its use in the regulation tasks with big amplification factor. The conducted researches demonstrate wide functional potentials of the considered mechanism of PFC and expediency of its use alongside with the classical methods of correction. In this connection the question about development of a methodology of PFC and its inclusion in the modern engineering instrument of ARS design is quite appropriate.

Keywords: automatic regulation systems, parallel feedforward correction, compensation of transfer poles, control by transfer zeroes, correction of the amplitude-phase characteristics, infinitely high gain

Acknowledgements: This work was supported by a grant from the Russian Foundation for Basic Research, projects No. 13-08-00161а and No. 13-08-00948а.

For citation:
Filimonov A. B., Filimonov N. B. Concerning the Problem of a Parallel Feedforward Correction of the Regulation Systems, Mekhatronika, avtomatizatsiya, upravlenie, 2015, vol. 16, no. 8, pp. 507—514.
DOI: 10.17587/mau.16.507-514

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