Research On Coiling Tension Control System Of Cold Rolling

Tension control is known to be the most important system in every winding machine. Materials such as paper,plastic film,textile,rubber flake or strip steel,are unwound from or wound onto the machine by the control of specific tension.The tension affects the processed material greatly. Extremely big tension will lead the distortion or break of the material while extremely small tension makes the stress distortion layer by layer and affects the processing quality;frequent tension change will lead the degree of tightness change,and it will also bring the low productivity of qualified products.Therefore the tension control is the key point in the high precision Coiling system.The research on the tension control of the coiler in the coiling section is done in this thesis.First,the thesis introduces the development of tension control system at home and abroad, analyze and study the tension control principle of the coiler, put emphasis of study on the realization way of coiler tension control and the compensation computation of inertia torque, and adopt the compound tension control mode by comparing several way of tension realization.Secondly, the coiling characteristic of coiler and the dynamic tension model are studied while the mathematical model of coiler tension control system is established. Given the bad performance of conventional PID control in the coiler system which is complex,nonlinear and time-varying, the fuzzy PID control as the method to control tension system is used, that makes the best use of the characteristic of fuzzy PID control which does not rely on the accurate mathematical model and has strong robustness to parameter change.Thirdly, response simulation between fuzzy PID and conventional PID is done by SIMULINK environment of MATLAB. The simulation results show that the combination of fuzzy PID control system can get the adjustment time and overshoot less,the behavior of the system better,theability to resist disturbance better,and much more robustness than conventional PID control system. As a result, this fuzzy PID algorithm is suitable in tension control system. Finally, the input scaling and output scaling factors of the fuzzy PID controller are optimized by GA.Then the relationship between the input scaling and output scaling factors and diameter of strip steel are gotten by Cubic spline interpolation,which provides basis for the online adjustment of the input scaling and output scaling factors and the optimal control of tension control system.