Application And Research Of Tension Control System For Single Stand 4-High Aluminium Strip Cold Mill

Under the background of 1900mm single stand 4-High aluminium strip cold mill, The main focus is put on the tension control system during cold rolling process. With SIEMENSE PLC, the open loop tension control system is developed. Meanwhile the disadvantage of conventional open loop tension control system is pointed put, and the algorithm of closed loop tension control is deeply researched. This article puts fuzzy intelligent control technology into conventional closed loop tension control system, and response simulation between conventional controller and new controller is done by SIMULINK environment of MATLAB. The simulation results show that the combination of fuzzy and PID control system can get much better precision than conventional PID control system. The main work and results are as follows:(1) Based on the principle of tension and drive control system, the maximum invariable torque open loop tension set algorithm is developed. Tension control uses the strategy of the maximum invariable torque, uses dynamic compensation and taper tension control, and controls aluminium strip tension by controlling the current.(2) The open loop tension control system has the advantage of good stability, but it has bad control precision and dynamic compensation. According to the disadvantage of open loop control system, the algorithm of closed loop tension control system is deeply researched.(3) According to the problem of slow response of conventional PID controller of tension control system, the combination of fuzzy controller and PID controller is introduced to the closed loop tension control. When the control deviation is bigger, the fuzzy controller is used in order to get faster response. When the control deviation is smaller, the PID controller is used in order to get rid of steady error. The simulation result by SIMULINK shows that the combination of fuzzy and PID closed loop tension control system not only has fast dynamic response but also has good steady precision.(4) Based on the research of the tension control system for aluminium strip, a set of reasonable tension control computer system including hardware configuration and software structure is given.The actual results and record curves show that the tension control system runs steadily. The fluctuation of tension is less than 1% of setting value during steady rolling phase. The research results in the paper are useful to the tension control of single stand aluminium cold mill. They are practical and can be applied in similar project. Additional, there is also a breakthrough in the method of closed loop tension control.