Variable-parameter drum control method in tobacco shred drying process

Abstract

The invention discloses a variable-parameter drum control method in the tobacco shred drying process. The control method is realized by a cascade control system consisting of an outlet water ratio controller and a hot air temperature controller, wherein the hot air temperature controller is taken as a subloop or an inner loop in the control system; the outlet water ratio controller is taken as a main loop or an outer loop in the control system; the controlled output of the outlet water ratio controller is taken as a stated input of an inner loop controller; the control system is characterized in that the outlet water ratio controller adopts a variable-parameter PID (proportion integration differentiation) control way with a dead zone; when the difference between the outlet water ratio and a set water ratio is within the range of the dead zone, a PID controller does not execute the control action, so that the damage to an executing mechanism caused by frequent actions is avoided, while the difference is within a set smaller range, the proportion coefficient is reduced, the integration coefficient and the differentiation coefficient are increased, and when the difference is within a larger range, the proportion coefficient is increased, the integration coefficient and the differentiation coefficient are reduced; and therefore, the response speed is increased, the steady-state error is reduced, high stability is ensured and the integration saturation is prevented.

Description

[0001] technical field [0002] The invention relates to the relevant technical field of tobacco production, in particular to a method for controlling variable parameters of a drum drying process. [0003] Background technique [0004] In the tobacco processing process, the shred drying link is an important link in the shredded production line, which directly affects the quality of the finished shredded tobacco. Its main function is to ensure that the shredded tobacco at the outlet of the shred dryer reaches the moisture content required by the cigarette process, improve the shredded rate and filling value of the shredded tobacco, and change the physical properties of the shredded tobacco. [0005] During the drying process, when the temperature of the hot air in the drying cylinder fluctuates, the physical quality (whole shred rate, shredded shred rate and filling value) and sensory quality of the exported shredded tobacco will be greatly affected ("Journal of China Tobacc...

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Problems solved by technology

[0007] However, this scheme based on traditional PID (fixed controller parameters) control has the following two outstanding problems: First, in the normal production stage, due to the nonlinearity and hysteresis of the silk drying process, the parameters of the PID controller for moisture content cannot be determined. If it is set in the optimal state, the outlet water content fluctuates greatly; second, the outlet water content measurement contains serious noise, and the original first-order filter has serious defects: the filter time constant is too large, the control effect lags, and the control quality declines; the filter time The constant is too small, the measurement fluctuates greatly, and the control action is frequent, which will also cause frequent control of the hot air temperature, thus affecting the service life of the actuator

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