Algorithm of coordinated control of an open-type headbox

Abstract

The control system of an open-type headbox has a high complexity, which is associated with the need not only to stabilize the parameters of the object, but also to carry out coordinated control of it in the case of automatic transfer of a paper machine from one type of product to another for a minimum time. A mathematical model of an open-type headbox as an object of mass level control has been developed. In the model, the output variable of the control object is the level of mass in the injection chamber, and the control action is the mass flow rate supplied to the injection chamber. The model takes into account the disturbing action - the area of the discharge slot. On the basis of the developed model, two options for constructing an algorithm for controlling the pressure box during its transfer from one mode to another are considered. The structure of the algorithm for coordinated control of the pressure box is developed. An illustrative example of application of the developed algorithm is given. The calculations of the optimal transient process in the object confirm the effectiveness of the developed control algorithm. The algorithm of coordinated control is applied to the standard pressure box YANO-180. The development of the algorithm for transferring the pressure box from the working (0.485 m) to the maximum (0.575 m) height of the mass level in the pressure box for 180 seconds is demonstrated. The calculation results show that the coordinated control algorithm provides the transfer of the mass level to the maximum height for a given time. The algorithm developed on the basis of the obtained mathematical model allows to control the level of mass in such a complex object as an open-type headbox when transferring a paper machine from one mode of operation to another for the time specified by the coordinated control system.