РАЗРАБОТКА РАСПРЕДЕЛЕННОЙ СИСТЕМЫ УПРАЛВЛЕНИЯ ТЕПЛОВЫМИ ПРОЦЕССАМИ ГИДРАВЛИЧЕСКОГО ПРЕССА

Abstract

The necessity of regulating the temperature of the coolant in hydraulic presses, providinghot gluing of plywood, regulating the pressure in the press channels and maintaining technologicalparameters at a given level, is considered. A column hydraulic press P-714-B for hot gluing ofplywood, installed at the Ust-Izhora plywood mill, is considered as a control object. The articleprovides a description of the column hydraulic press. To monitor the parameters of the presentedinstallation of plywood production, it is proposed to consider the heating press plates and plywoodpackages as an object with distributed parameters. To develop a mathematical model of the controlobject, a functional diagram of this device with the main equipment and technological flows ofthe coolant was considered. A technique has been developed for modeling objects of this class asobjects with distributed parameters. Consideration of the processes occurring in the channels ofthe heating plates made it possible to formulate differential equations of motion that describe theflow of the working medium in the system of channels. The developed method of mathematicalmodeling of heat propagation in the heating plates of the press and plywood packages made itpossible to draw up a mathematical model for the object under consideration. This mathematicalmodel turned out to be quite complex, and it is not possible to solve the resulting system of partialdifferential equations analytically (to isolate the transfer function). For a numerical analysis of theconsidered control object, a discrete model of equations and a computational algorithm werecompiled. In the process of compiling discrete models, the problems of “joining” the boundaryconditions were solved, the stability of the computational scheme was ensured, and the steps ofdiscretization with respect to spatial variables were selected. Software was specially developed forcomputer 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 aresult of which the frequency characteristics of the object under study were obtained. These characteristicswere used in the synthesis of a distributed high-precision controller.