Research on feedforward control system of tandem cold rolling mill’s hydraulic AGC and its computer control strategy

The high-speed tandem cold rolling mill is the typical complicated electromechanical system. Since the request to the quality of cold rolling sheet strips is higher and higher, the control system of the tandem cold rolling mill becomes more and more precise and intellective. And the feedforward control system of the hydraulic AGC is its important constituent part for eliminating the thickness deviation of the product. The traditional feedforward AGC only compensates the strip's entry thickness deviation, but this article adds the compensation of the tension vibration to eliminate the thickness deviation because of the tension vibration. Because of the variable velocity of the strip, the fixed-step delay of the traditional strategy is not very precise, so a new method of the dynamic time delay is provided in this article, which tracks the strip more precisely using the dynamic array. When measuring the thickness of the strip using the thickness gauge, the average thickness measurement of the strip segment is used instead of the measurement of the single point, gaining better control effects. At the same time, the computer control strategy of the feedforward AGC is researched, and the control strategy adapting the distributed computer control system is provided. All strategies have been applied in the practical project, and favorable control results are gained, which the thickness precision of the strip product is improved.