一种带有反馈滤波器的自整定Smith预估器设计及其在纸张横幅定量控制中的应用

Design of Self-tuning Smith Predictor with Feedback Filter and Application in Cross Direction Basis Weight Control of Paper Machine

关键词:  纸张横幅定量  非方高维矩阵  大时滞过程  Smith预估器

Key Words:cross direction basis weight of paper  non-square high-dimensional matrix  large delay process  Smith predictor

摘要:针对纸张横幅定量控制所存在的强耦合及大时滞特性，本研究提出了一种Smith预估器加模糊自整定PID复合控制策略。采用“区域化点”法并引入前置矩阵对非方系统进行降维，然后取降维后系统关联矩阵的逆矩阵作为解耦器，将系统转变为与稀释水阀数量一致的多个单回路。针对稀释水流浆箱的横幅定量控制系统大时滞特性，设计一种带有反馈滤波器的自整定Smith预估器控制方案，其主控制器采用模糊自整定（Fuzzy-PID）控制器。反馈环滤波器的存在使其可在模型失配情况下降低系统对模型失配误差的敏感度，进一步增强系统鲁棒性。仿真实验结合现场实际应用案例证明，该方案具有可行性和有效性，并且可将横幅定量差指标控制在2%以内。

Abstract:Aiming at the strong coupling and large time delay characteristics of the cross direction basis weight control， the paper proposed a Smith predictor plus fuzzy self-tuning PID composite control strategy. The "area converted to point" method was adopted and introduced the pre-matrix to reduce the dimension of the non-square system， and then took the inverse matrix of the correlation matrix of the system after the dimension reduction as a decoupler to transform the system into multiple single loops with the same number of dilution water valves. A self-tuning Smith predictor control strategy with a feedback filter was designed for its large time-delay characteristics. Its main controller adopted Fuzzy-PID controller. The existence of feedback loop filter reduced the sensitivity of the system to model mismatch errors and further enhanced the robustness of the system under the condition of model mismatch. Finally， the feasibility and effectiveness of the scheme proposed in this paper were shown by the simulation test combined with the actual application case， and the difference indicators of cross direction basis weight was controlled within 2%.