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• DEVELOPMENT OF A DISTRIBUTED CONTROL SYSTEM OF THERMAL PROCESSES IN A HYDRAULIC PRESS

  A.L. Liashenko

  2021-12-24

  Abstract ▼

  The necessity of regulating the temperature of the coolant in hydraulic presses, providing
  hot gluing of plywood, regulating the pressure in the press channels and maintaining technological
  parameters at a given level, is considered. A column hydraulic press P-714-B for hot gluing of
  plywood, installed at the Ust-Izhora plywood mill, is considered as a control object. The article
  provides a description of the column hydraulic press. To monitor the parameters of the presented
  installation of plywood production, it is proposed to consider the heating press plates and plywood
  packages as an object with distributed parameters. To develop a mathematical model of the control
  object, a functional diagram of this device with the main equipment and technological flows of
  the coolant was considered. A technique has been developed for modeling objects of this class as
  objects with distributed parameters. Consideration of the processes occurring in the channels of
  the heating plates made it possible to formulate differential equations of motion that describe the
  flow of the working medium in the system of channels. The developed method of mathematical
  modeling of heat propagation in the heating plates of the press and plywood packages made it
  possible to draw up a mathematical model for the object under consideration. This mathematical
  model turned out to be quite complex, and it is not possible to solve the resulting system of partial
  differential equations analytically (to isolate the transfer function). For a numerical analysis of the
  considered control object, a discrete model of equations and a computational algorithm were
  compiled. In the process of compiling discrete models, the problems of “joining” the boundary
  conditions were solved, the stability of the computational scheme was ensured, and the steps of
  discretization with respect to spatial variables were selected. Software was specially developed for
  computer modeling. With its help, the temperature values at the control points were calculated.
  The presented mathematical model made it possible to carry out a numerical experiment, as a
  result of which the frequency characteristics of the object under study were obtained. These characteristics
  were used in the synthesis of a distributed high-precision controller.