PROCEDURE FOR THE IDENTIFICATION OF A PROCESS AFFECTED WITH DELAY WITH COMPENSATION AS WELL AS INSTALLATION FOR THE REGULATION OF A PROCESS OF THIS TYPE.

摘要

A mathematical identification procedure is presented for a process exposed to delayed compensation, especially comprising heating followed by cooling, for example in the extrusion of thermoplastic materials. Starting from the first regular state, the variable control (y) of the first controller (33) is set to a first constant value (80%) and that of the second controller (34) is eliminated. After the determination of an inflection point in the control variable curve (x), a first IT1 model of the processing control system (32) is identified. The process is controlled as a function of the first IT1 model, at least until a second regular state (170º C) that differs from the first. From the tangent (wh) at the first inflection point, the value of the variable (y) and the control variable (x) of the first and second regular state, a VZ2 model is identified. Starting from the first regular state, the variable control (y) of the first controller (33) is set to a first constant value (80%) and that of the second controller (34) is eliminated. After the determination of an inflection point in the control variable curve (x), a first IT1 model of the processing control system (32) is identified. The process is controlled as a function of the first IT1 model, at least until a second regular state (170º C) that differs from the first. From the tangent (wh) at the first inflection point, the value of the variable (y) and the control variable (x) of the first and second regular state, a VZ2 model is identified. The VZ2 model describes the process kinetics (32) and the amplification coefficient for the first controller (33). From the second regular state the first controller (33) is deactivated and the control variable of the second controller (34) is set to a second constant value (20%). Once a second inflection point has been determined on the control magnitude curve (x), an amplification coefficient for the second controller (34) is determined, according to the formula: kik = (dxwk / dt + Kih .infinity) / (YLLMTUM). In this equation: dxwk / dt is the slope of the tangent at the second inflection point and (kik) is the process amplification coefficient of the first identified IT1 model. Yinfinity is the value of the magnitude (y) in the second regular state. YLLMUTM is the second constant value of the control variable. An independent claim is included for a process-based equipment, which is used, for example, to control an extruder of plastic material. There are controllers that work at different intensities. Preferred features: the most outstanding features include the typical 170º C working point of a regular state, which follows heating. The control process is elaborated mathematically in an additional way, including formulas in the form of approximations, expansions of polynomial series, of up to fifth order with respect to the relation of time constants of the process path. Quantified empirical constants are also supplied.