Research Of The Gauge Control System Based On The Stair-Like Generalized Predictive Control

With the continuous development of computer ability and control theory,the automation of rolling system is gradually improved.Steel plate,as an indispensable resource of modern industry,robot and military industry,has been put forward the expectation of higher quality index.So the accuracy of strip thickness is undoubtedly one of the important indexes of its finished product quality.Therefore,it is necessary to study the algorithm of automatic gauge control system.Combining with the mill spring equation,this paper discusses the influence of various interference factors on the exit thickness of the plate.The gauge control system and rolling principle of the rolling mill are analyzed,and the mathematical model of the rolling mill gap control system is established by analyzing the internal components and related mechanisms.Considering the change of oil temperature,a series of parameters such as volumetric elastic modulus and viscous resistance of the oil are slowly changing during the actual rolling process,so the dynamic parameters of the hydraulic system can not be accurately estimated.In order to improve the accuracy of the strip exit thickness of the gauge control system,it is necessary to identify the variation characteristics of the model parameters accurately during the rolling process.In this paper,a recursive least squares algorithm based on auxiliary model for variable forgetting factor is designed.The algorithm uses the output of the auxiliary model instead of the real output of the system to identify the system parameters,reduce the influence of noise and combine the variable forgetting factor to enhance the tracking of the system and reduce data convergence error,improve the accuracy of model identification;the rolling process modeling is complex,the lag time is difficult to determine due to roll speed fluctuation,and multivariate,more disturbance.This paper studies stair-like generalized predictive control algorithm,which introduces a stair-like control strategy based on generalized predictive control.By imposing constraints on the control amount,the control input is more stable and conforms to the control law of the actuator.It not only preserves the influence of generalized predictive control to overcome the characteristics of time-delay,but also has the advantage of high robustness.It also avoids the calculation of inverse matrix in solving the optimal control law,which reduces the computational complexity and improves the calculation speed.Therefore,it is more suitable for online control of actual engineering projects.In order to further verify the control effect of the algorithm,this paper takes a cold rolling mill as the object and combines the actual situation of gauge control system to verify its control performance.The simulation results show that the stair-like generalized predictive control show better advantages in terms of tracking performance and adaptive ability than conventional generalized predictive control.The effectiveness of the algorithm is verified,which lays a foundation for further research on the gauge control algorithm.