Study On Looper Control System For 1450mm Tandem Cold Mill Of Qianan Steel

In recent years,with the rapid development of cold rolling technology,the main feature of production lines is specialized,high-speed production,continuous and automatic highly.Looper is the core equipment to ensure production line producted continuously,high-speedly and automatically.Therefore,the research and development on looper system control have great signific,ance for the progress of the entire steel industry.In the production process of silicon steel based on 1450mm tandem cold mill of qianan steel,the control system of looper have some problems,such as the slip of tension tension roll,looper position deviation,automatic position control in the welding mode was imperfect and so on.Based on the problems,the tension control and position control of looper system was studied in order to analyze and solve the problems.Finally,control method and program design was optimizaed and applied to the actual production process.The main work includes:(1)The technological process,characteristics of technical equipment and the loop system structure of 1450mm tandem cold mill was introduced which was imported from Japan by Mitsubishi-Hitachi,At last,the control problem of the looper system was analyzed.(2)Based on the tension control of looper system,the tension mechanism and main factors for tension control of looper was analyzed.Mainly from the following several aspect,such as verification of design theory of tension roll,tension torque compensation calculation,PID control theory,vector control of motor,etc.The purpose is to achieve tension control stability and reduce the fluctuation and response time when the tension changes.At last,the problem of tension roller slip is solved by adding the current loop and Droop control.(3)Based on the looper position deviation and automatic position control in the welding mode was imperfect,the process of Hitachi TA47 series encoder to realize looper position cauculate in real time and looper control model was analyzed,meanwhile for engineering optimization and safety considerations,three stop models in case of emergency were ventured.At last,two solutions were proposed which were the looper zeroing compensation function and speed correction calculation function.(4)The optimization program was designed detaily from two aspects of hardware and software,which were the funshion of ACR control,Droop control,Zero compensation and looper speed correction calculation function.The problems mentioned above were effectively solved,and the looper control system stable operation.The effects were good in pratical according to the operation date.Tension fluctuation amplitude was up to 45%and fluctuation time lasted about 50s before optimization,in the state the tension fluctuation was about 15%.After optimizatoon,the tension fluctuation amplitude was less than 20%,and 30s later tended to be stable.Especially,the tension setting value was consistent with the actual value basically and sip phenomenon was eliminatec.The deviation of position control was decreased from 0.17%to 0.03%.In the whole process of looper automatic position controlled,the loop could stable operation without manual intervention,and the continuous operation of the production line was realized.