大时滞过程自整定PID及其在定量控制中的应用

针对纸张定量控制的难点，提出了一种能用大时滞过程的自整定PID／PI控制算法。通过改进型继电反馈频域响应辨识方法获得实际过程Nyquist曲线与S平面负实轴和虚轴交点处等幅振荡的幅值和频率，给定幅值裕度和相角裕度鲁棒性能指标，确定自整定PID／PI控制器参数，此算法具有参数整定简单，对实际过程模型的依赖性小，鲁棒性强及易于实现等优点，适合于含有大时滞的工业过程控制。

Auto-Tuning PID for Large Time-Delay Processes and Its Application to Paper Basis Weight Control

The brief arts and crafts of an ordinary fourdrinier were introduced. After analyzing the intractable points of paper basis weight control, a PID/PI control algorithm was presented which is capable of controlling large time delay processes. The oscillation amplitude and frequency at the point where the Nyquist curve of the process intersects the negative imaginary axis in S plane are obtained via modified relay feedback identification method in frequency domain. In terms of the information obtained above, the auto tuning PID/PI parameter values are thus calculated according to the specified robust specifications of amplitude margin and phase margin. The algorithm is of such advantages as simple parameter adjustment, little dependence on process model, strong robustness and easiness to implementation. And it is also very suitable for controlling industrial processes with large time delay.