Study On Step-by-step Control System For Coiler Of Hot Rolling Mill Based On H_∞ Control

In the process of hot rolling mill, wallop is very large when winding, which influences production heavily. So developing the control system to realize step-by-step control is significative.Based on the real work process of coiler at worksite, a mechanical model for coiler control system is built. This is the first time in China to develop an electro-hydraulic servo system including the position-adjusting loop and the pressure-adjusting loop. The mathematical model is also built and system nonlinear effects are analyzed, especially nonlinear effects of electro-hydraulic servovalve, pump station, and pipes.In the thesis, robust design methods for controlling strategy in the coiler control system are studied in detail. One robust compensation adjustment is presented, based on which and H?mixed sensitivity control method, then a new H- control method is brought forward and is applied in the pressure-adjusting loop of this system. H mixed sensitivity control method is applied in the position-adjusting loop. System simulation and experiments prove that using these two control methods, performance of close-loop system is very good and excellent robustness is obtained too.The control software is developed by using Visual C++ language. The results show that the software has strong application value and its interface is interactive and easy to operate.Results show that in the system, step-by-step control is realized, and vibration and striking are largely decreased too. This provides theoretic and experimental base for developing high-level step-by-step control system and improving installation of coiler and quality of production.