The predictive function cascade control for a cold rolling mill process
Some substantial improvements was made in strip thickness control in cold rolling using the cascade predictive function control (PFC) with PID control system, the improvements with PFC cascade control methods compared to conventional PID cascade control can be judge to at least 1-3％ more strip within tolerances and smaller deviations in strip thickness. The major difference compared to conventional control is the extensive use of the PFC cascade technique to automatically adjust the regulators to optimal performance. It can seek tradeoff between performance and disturbance rejection. Predictive control is widely used in industry in recently, and there are a lot of advantages, e.g. only need approximate model, have good tracking performance, have strong robustness for model mismatch. These advantages are incapable for PID control. But for disturbance rejection, PID control method is better than PFC (Predictive Function Control). The one of difficult for designing control system of hydraulic thickness control for the coldstrip mill in the rolling process seeks tradeoff between robustness to disturbance rejection. So a novel cascade scheme for combining predictive function control (PFC) with PID is presented. The load disturbance was overcame by use of PID control in inner loop, and good tracking performance and robustness can be got by use of PFC control in outer loop for overcoming parameter change. The simulation results show that the advanced control strategy has more favorable dynamic characteristics than PID cascade control scheme for tracking tasks. Some substantial improvements was made in strip thickness control in cold rolling using the cascade predictive function control (PFC) with PID control system, the improvements with PFC cascade control methods compared to conventional PID cascade control can be judge to at least 1-3％ more strip within tolerances and smaller deviations in strip thickness. The major difference compared to conventional control is the extensive use of the PFC cascade technique to automatically adjust the regulators to optimal performance. It can seek tradeoff between performance and disturbance rejection. Predictive control is widely used in industry in recently, and there are a lot of advantages, e.g. only need approximate model, have good tracking performance, have strong robustness for model mismatch. These advantages are incapable for PID control. But for disturbance rejection, PID control method is better than PFC (Predictive Function Control). The one of difficult for designing control system of hydraulic thickness control for the coldstrip mill in the rolling process seeks tradeoff between robustness to disturbance rejection. So a novel cascade scheme for combining predictive function control (PFC) with PID is presented. The load disturbance was overcame by use of PID control in inner loop, and good tracking performance and robustness can be got by use of PFC control in outer loop for overcoming parameter change. The simulation results show that the advanced control strategy has more favorable dynamic characteristics than PID cascade control scheme for tracking tasks.
Predictive function control Robustness The advanced control strategy Cascade control scheme Cold rolling
Zhihuan Zhang
The Institute of Mechatronic Design and Control Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo, China
国际会议
杭州
英文
522-525
2009-04-08（万方平台首次上网日期，不代表论文的发表时间）