Research and Implementation of Optimized Strip Temperature Computer Control System of Heating Furnace
|Keywords||continuous annealing line strip temperature control fuzzy PID flying gauge change control|
The continuous annealing technology has been applied in strip production widely. The strip temperature control is a most important control system in the continuous annealing process control. It has important significance for improving production quality and reducing energy consuming. There are three aims to research the optimized strip temperature control, guaranteeing the strip temperature control precision, reducing the energy consuming and improving the efficiency of flying gauge change control.The Level 1 strip temperature control system in the heating furnace of 1550 continuous annealing line in Bao Steel is studied in the thesis. There are some shortcomings in the original system, such as, the large strip temperature control error, the heating zone closed with high frequency and the low efficiency during the flying gauge change control period, etc. In order to overcome these shortcomings, three key problems, strip control model, the structure of strip control system and control algorithm are discussed in detail.About the strip control model, the dynamic characteristics of strip temperature are analyzed in detail. The strip temperature will be affected by furnace temperature, gas flow rate, strip thickness and line speed. The simplified mathematical models of furnace temperature and strip temperature are derived from first principles and the parameters are identified based on optimal algorithm. The characters of four types strip temperature control system and two type flying gauge change control scheme in Bao Steel are discussed in detail. A hybrid control scheme named "feed forward+feedback" is proposed to improve the efficiency during the flying gauge change control period. Further, a set-point adjust fuzzy PID controller is designed for the strip temperature control and a single input fuzzy PID controller is designed for the furnace temperature control. The simulation and experiment results show the validation of the control scheme.