在分布曲线控制中,传统的积分平方误差指标仅考虑输出曲线与目标曲线的误差面积,忽略了分布曲线的内在特征结构。该文从曲线相似度度量出发,提出了一种基于梯度特征的分布曲线模型预测控制算法。该算法采用B样条模型描述分布曲线对象,基于梯度特征度量曲线相似度,综合曲线数值信息与梯度信息构造优化命题,并通过复合梯形方法对优化命题进行离散化,求解得到最优控制策略。仿真结果表明:该算法可提高曲线切换过程中输出曲线与目标曲线的相似度,实现了曲线形状的自然过渡。
Abstract
In the control of distribution processes, the traditional integral square error performance index only considers the area between the output curve and the target curve, which ignores the structural features of the distribution curve. A gradient feature-based model predictive control algorithm that takes into account the curve similarities is developed for distribution processes. The algorithm first models the distribution process curve with B-splines. Then, the algorithm quantifies the similarity between the curves based on gradient features and optimizes the design by combining numerical and gradient information. The composite trapezoidal rule is then used to discretize the optimization proposition. Finally, the optimization proposition is solved to get the optimal solution. Simulations show that this algorithm improves the similarity between the output curve and the target curve during curve switching with natural transitions of the curve shape.
关键词
模型预测控制 /
分布曲线 /
曲线相似度 /
梯度特征
Key words
model predictive control /
distribution process /
curve similarity /
gradient feature
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] CONGALIDIS J P, RICHARDS J R. Process control of polymerization reactors:An industrial perspective[J]. Polymer Reaction Engineering, 1998, 6(2):71-111.
[2] SAYER C, ARZAMENDI G, ASUA J M, et al. Dynamic optimization of semicontinuous emulsion copolymerization reactions:Composition and molecular weight distribution[J]. Computers & Chemical Engineering, 2001, 25(4-6):839-849.
[3] ALI M A, AJBAR E A A H, ALHUMAIZI K. Control of molecular weight distribution of polyethylene in gas-phase fluidized bed reactors[J]. Korean Journal of Chemical Engineering, 2010, 27(1):364-372.
[4] WANG H. Bounded dynamic stochastic distributions:Modelling and control[M]. London, UK:Springer-Verlag, 2000.
[5] WANG H. Robust control of the output probability density functions for multivariable stochastic systems[C]//Proceedings of the 37th IEEE Conference on Decision and Control. Piscataway, USA:IEEE Press, 1998:1305-1310.
[6] WANG H. Model reference adaptive control of the output stochastic distributions for unknown linear stochastic systems[J]. International Journal of Systems Science, 1999, 30(7):707-715.
[7] YUE H, WANG H, ZHANG J F. Shaping of molecular weight distribution by iterative learning probability density function control strategies[J]. Proceedings of the Institution of Mechanical Engineers, Part I:Journal of Systems and Control Engineering, 2008, 222(7):639-653.
[8] ZHANG J F, YUE H, ZHOU J L. Predictive PDF control in shaping of molecular weight distribution based on a new modeling algorithm[J]. Journal of Process Control, 2015, 30:80-89.
[9] VICENTE M, SAYER C, LEIZA J R, et al. Dynamic optimization of non-linear emulsion copolymerization systems:Open-loop control of composition and molecular weight distribution[J]. Chemical Engineering Journal, 2002, 85(2-3):339-349.
[10] 申珊华, 曹柳林, 王晶. 基于分布函数矩的聚合物分子量分布预测控制[J]. 化工学报, 2013, 64(12):4379-4384. SHEN S H, CAO L L, WANG J. Predictive control of molecular weight distribution in polymerization reaction based on moment of MWD[J]. Journal of Chemical Industry and Engineering (China), 2013, 64(12):4379-4384. (in Chinese)
[11] CAO L L, LI D Z, ZHANG C Y, et al. Control and modeling of temperature distribution in a tubular polymerization process[J]. Computers & Chemical Engineering, 2007, 31(11):1516-1524.
[12] ZHOU J L, LI G, WANG H. Robust tracking controller design for non-Gaussian singular uncertainty stochastic distribution systems[J]. Automatica, 2014, 50(4):1296-1303.
[13] BUEHLER E A, PAULSON J A, MESBAH A. Lyapunov-based stochastic nonlinear model predictive control:Shaping the state probability distribution functions[C]//2016 American Control Conference. Philadelphia, USA:American Automatic Control Council, 2016:5389-5394.
[14] 康岳群, 徐祖华, 赵均, 等. 分布曲线对象的无偏模型预测控制算法[J]. 化工学报, 2016, 67(3):701-706. KANG Y Q, XU Z H, ZHAO J, et al. Offset-free model-predictive control algorithm of distribution process[J]. Journal of Chemical Industry and Engineering (China), 2016, 67(3):701-706. (in Chinese)
基金
国家重点研发计划(2017YFB0603703);国家自然科学基金-浙江两化融合联合基金项目(U1509209);国家自然科学基金项目(61773340);中央高校基本科研业务费专项(2018QNA5011)