Research On Tension Control System Of Reversible Mill

Tension is a very important technological parameter in the cold rolling process. Obviously, it influences the whole rolling line. Inappropriate tension or unstable tension can not only affect the quality indicators of strip such as flatness and thickness, but it also reduces the yield of strip. Therefore, tension control system has become a very critical part of the cold rolling control system with high precision.The actuators of the tension control system in the single reversible mill are the coiler and the uncoiler. In this thesis, the coiler is mainly object to study the tension control system of the single reversible mill deeply.Firstly, the producing mechanism of tension and the control methods are analyzed in this thesis, which are usually used in the tension control system. Then, research on the tension control mechanism of the coiler deeply. The method about measuring tension and the calculate method of dynamic compensation torque and real-time coil diameter is introduced, which is used in the a factory.Secondly, A structure of control system in coiler which used in a factory is introduced and the working mode in this structure is analyzed. According to the structure of control system and the coiler works at the tension mode, the mathematical model of coiler tension control system is established and an adaptive PID controller is designed. In addition, the control effect of this controller is proved by the simulation results.Thirdly, after taking into account the tension control system of the model parameters, the effect of the variable gain PID controller will gradually deteriorate, so a controller based on dynamic matrix control is designed in this thesis. Furthermore, using the MATLAB to simulate the coiler tension control system based on the algorithm of adaptive PID and dynamic matrix control. The results of simulation indicate that the algorithm of dynamic matrix control make the tension system has less overshoot,better robustness and better capacity of resisting disturbance.Finally, to solve the problem that the deviation weighting matrix, control weighting matrix and deviation correction vector in the algorithm of dynamic matrix control are too hard to tuning, the genetic algorithm is used to find the optimal parameters in the different diameters of the coiler. Moreover, the diameters of coiler are matched with the optimal parameters by using the cubic spline interpolation. Afterwards, dynamic matrix control before optimization and dynamic matrix control after optimization are simulated by MATLAB. The simulation results show that the coiler tension control system performance is further improved by the dynamic matrix control optimized by genetic algorithm.