Model predictive control method and system for moisture and temperature of tobacco redryer

Abstract

The invention provides a model predictive control method and system for moisture and temperature of a tobacco redryer. The method comprises the steps of: process testing, carrying out a phase step test on a PLC (Programmable Logic Controller) of the tobacco redryer to obtain test data of operating variables, feedforward variables and controlled variables in the process of tobacco redrying; process identification, analyzing the obtained test data to identify a dynamic mathematical model of the process, wherein the dynamic mathematical model comprises a series of sub-models and each sub-model indicates the mathematical influence relationship between operating or feedforward variables and controlled variables; controller design, regulating the obtained dynamic mathematical model according tothe process theory and the operating experience to establish a model predictive controller; and controller operating, operating the model predictive controller, calculating the operating variables according to the requirements on controlled indexes, feedback on the measured controlled variables and changes of the feedforward variables during the operation of the model predictive controller, and then acting the operating variables on the designated PID circuit of PLC.

Description

technical field [0001] The invention relates to the field of tobacco processing, in particular to an advanced method for controlling moisture and temperature of a tobacco sheet redrying machine in a threshing and redrying production line. Background technique [0002] Tobacco redrying is a sorting and preparatory process for tobacco leaves to transform from agricultural products to industrial production raw materials. It is the "first workshop" of tobacco processing. It is formed on the basis of flue-cured tobacco production. Gradually develop into large-scale and industrialized, laying a supporting foundation for cigarette industrial enterprises to realize sheet cigarette feeding. [0003] The tobacco sheet redrying machine is the main equipment in the leaf threshing and redrying production line. Its purpose is to adjust the moisture in the tobacco sheet, remove the miscellaneous gas in the tobacco sheet, kill the pests and germs in the tobacco sheet, and make the tobacco s...

AI Technical Summary

Problems solved by technology

Although the production lines of most domestic threshing and re-baking enterprises have a high level of automation, there are still some problems in some control links: First, the baking temperature and flow settings, the wind speed of the mesh surface and the speed of the mesh belt cannot be automatically matched, and the hot air cannot be effective. Penetrating through the leaf layer, the moisture after baking is not uniform; the second is because the PID single loop only considers one loop itself (flow rate, or temperature at a single location, etc.), and the moisture control of re-baking currently mostly relies on manual closed-loop adjustment, and its control depends on The level and proficiency of the operators, and the moisture content of the exported tobacco leaves are easily fluctuated out of control due to the interference of the operators' familiarity with the equipment, operating experience, fluctuations in incoming material flow, and equipment working conditions (kinetic energy disturbances), resulting in unstable product quality.

[0011] The feed-forward information such as the operator’s reference to the feed is not timely enough, or the feed-forward information cannot be fully utilized; and the adjustment cycle is relatively long, making it difficult to timely and effectively respond to large fluctuations in the process (feed changes, or sudden changes in steam temperature and pressure). adjustment

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