The Analysis Of Looper Control Model Based On The Optimal Control Theory

The hydraulic looper system of Baosteel hot mill used the combining control method of ILQ (Inversed Linear Quadratic) control technology and traditional PI control. Compared with only the traditional PI control technology, the combining control method have more advantages, such as fast response, high control precision and rolling process stability. But the looper control system also has some problems, mainly include:(1) ILQ control has bad robustness,can not work normally and get a high failure rate when disturbances is bigger, The. switch between ILQ control and the traditional PI control is not stable in the original control system.(2) In the commissioning period the foreign SV mainly aimed at of carbon-steel, without considering other special material. But current production undertake a lot of silicon steel, trixiality production task, the original control system is not stable on special steel grade.(3) Because of The blockade of foreign technology, we failed to completely grasp the core technology of ILQ control.In this situation, it is necessary to further study the ILQ control system, grasp their mathematical principle and adjusting method, then implement the optimization to reduce the failure rate of ILQ control and improve ILQ and traditional PI control switch stability, lower tension fluctuations, to meet the production requirements. This paper start from the looper control model, tension fluctuations analysis, then deepens gradually, analyzes the reason of failure in ILQ control and fluctuation of tension, then make the steps and carry into execution, finally to evaluate the effects. The steps significant reduction ILQ control of failure and tension fluctuations. The subject of study can be summarized as follows:(1) to make a thorough analysis of the current control model, from the looper basal control theory to the current popular control theory, eventually master the ILQ control mathematical theory, according to the looper physical model of HSM to sort the basic structure of looper ILQ control system.(2) To retest the replacing part Looper characteristic of equipment after production, in order to achieve a more accurate control effect.(3) To understand original control procedure of the looper thoroughgoing, to acquire the application of ILQ theory, in the meantime, to find the possible existence mistake or insufficient. Base on deep grasp the original control system, to modify, to adjust, to increase ILQ control robustness and to reduce its failure.(4) To analysis all reasons of tension fluctuation, to make a series of measures, it is include optimizing control parameters, adjust the speed control mode and subsection control methods. In order to reduce risk, this topic take first compile on the online simulation program, after testing it has good circumstances and result then putting into use. It sharply reduced tension fluctuations. In addition, the topic analysis and optimizes the working condition about angle of Looper as well.Through carrying out this topic, it has great significance on effectively reducing the tension fluctuations and failure of ILQ control of failure, and improving the control level and product quality. At the same time, its analysis method to deal with problems can be extended to similar control system, promote the development of control engineering and control technology.