Study On Strategies Of Cold Rolling AGC Controller Based On Controllers'switching And Gain Reconition

For cold rolling strip products,the longitudinal thickness accuracy is an important indicator to measure the quality.It is a hot issue to explore how to improve the gauge control accuracy,and it has a great practical significance for our country to master the core thickness control technology and realize the transformation from a big steel country to a powerful one.The paper discussed the problem of how to improve the thickness control precision of the rolling mill under the state feedback control and the complex working conditions.A reduced-order state observer is designed for the problem that the flow state of servo valve is hard to be obtained in electro-hydraulic position servo systems.Then a pole assignment research based on the designed reduced-order observer is given and the feasibility analysis is tested through simulations.In order to solve the problem of steady state error,the mechanism that the double-order state feedback(DOSF)control system has static error is analyzed and a three-order state feedback(TOSF)controller without static error is designed.To overcome the high order of the TOSF control system,a finite frequency domain weighting switching algorithm is adopted to realize TOSF-DOSF dual-controller switching control,which can reduce the sensitivity of control action on weighting coefficient changing.Simulations and experiments on some 1780 mm cold rolling show that the design makes the system a good dynamic and static performance with a small switching impact.As the controlled objects of rolling mill gauge control system have time-varying gains and a hysteresis quality,a parameter estimator is designed and the convergence condition it works is obtained.For the purpose of improving the system adaptive capacity to the changing work conditions,a adaptive control algorithm is designed with the identified parameters.Through numerical simulations and rolling experiments on aluminium plates,the design was proved can effectively improve the control precision of the control systems with slow time-varying gains.To sum it up,the paper around the problem how to improve the cold rolling thickness control precision.Some thickness control strategies of hydraulic AGC controller wasimproved.The all those proposed arithmetic: a pole assignment design based on reduced-order observer,finite frequency domain weighting switching control of electro-hydraulic position control systems and maintain performance control of cold rolling AGC based on gain recognition provided a theoretical basis for improving the control precision of the position inner ring and gauge outer ring of the hydraulic AGC and have a practical significance.