| Laminar cooling is one part of the technique for the control of rolling and cooling, it effects the tissue and properties of strip directly. So laminar cooling process plays an important role in hot strip production. The control accuracy of the coiling temperature of the hot strip laminar cooling system is the crucial factor to guarantee the better quality and flatness of strip. This paper takes a laminar cooling system of a domestic hot strip factory for background, and has a deep study for how to raise the accuracy of cooling temperature of the hot rolled strip.As the mathematic model of hot strip laminar cooling system is based on the theory of calorific, so the paper first analyze the models of heat transfer, and particular analyze the mathematic model of the process of this hot strip laminar cooling system. Its calculate precision influences the last effect of control cooling. The coefficient P is the most important parameter to determine the precision of control, so choose a proper P has an important mean to the accuracy of the coiling temperature. So the proper heat transfer model is very important thing which can improve the accuracy of the coiling temperature.Study and analyze the laminar cooling control strategy, and particular analyze the all functions of control strategy. It can be seen from the system working process that laminar cooling system is a complex control system which mainly depend on pre-set calculate and feed-forward correct calculate, and assist by feed-back control. Based on the application in produce, analyze the performance of this control system and bring forward the improving measure to the problem existing in the control system.For lack of precise model in laminar cooling process in hot strip mill, traditional Fuzzy Prediction Controller is difficult to acquire satisfactory control result. A fuzzy prediction control project based on Self-adjustment Parameters control is proposed in this paper for solving the existing problem. The fuzzy adjustment rule of on-line adjustment of proportional factor is worked out by using language variable locus and manual control experience and the controller can carry out regulation in short time with fast response, and can effectively eliminate the oscillatory instability, the results of simulation experiments prove that this project is correct and practicable for the delay and nonlinear system.In a hot steel strip line, the coiling temperature control is critical for strip quality. By translating the design of the coiling temperature control into the optimization of its parameters, PSO can be used to explore the whole parameters space effectively in parallel in order to achieve the optimum solution. With adopting mutation and re-randomizing operator and introducing adaptive inertia weight, the global convergence performance and the effectiveness of the proposed algorithm is enhanced. The result indicated that the difference between the calculated temperature and target coiling temperature was controlled in the rang between -15℃and+15℃. The method obviously improves the accuracy of coiling temperature, so the application of this method has a great future. Simulations with a model validated using actual plant data are conducted, and the results have confirmed the effectiveness of the proposed control method.
|
PDF Full Text Request