Model predictive control of flat sheet processes: robustness and auto-tuning

在造纸生产中，板材生产过程是一个具有空间和动态成分的二维大系统，必须对其进行持续的控制和监控，以确保产品质量。空间控制，也称为交叉方向(CD)控制，用于在垂直于纸页移动的方向上保持均匀的产品质量。现有的工业控制技术基于模型预测控制方法，需要在每个采样间隔内在线求解约束二次优化问题。随着这些过程的规模和规模的增大以及对产品质量的要求，如何在建模和扰动不确定性的情况下稳健地解决优化问题，以及如何调整控制器参数以获得良好的闭环系统性能是关键；挑战包括所涉及的输入和输出变量的高维、主动执行器的约束和较短的控制间隔。 我们的目标是开发、评估和应用大型平板过程的交叉方向控制的先进方法，解决模型预测控制框架中的健壮性和控制器整定问题；特别是采用模型预测方法，研究现有的解决方案，开发用于稳健控制设计和控制器自动调整的新算法，考虑可行性和闭环系统稳定性问题，探索横向模型中的稀疏矩阵结构，并研究它们在Honeywell控制系统中的有效实施。 霍尼韦尔是造纸设备和相关控制系统的主要供应商。成功 该项目的完成将增强霍尼韦尔的造纸控制技术，使加拿大纸浆和造纸业总体受益。此外，强大的产学合作将加强霍尼韦尔温哥华的员工留住和吸引计划。

In papermaking, a flat sheet process is a large-scale two-dimensional system with spatial and dynamic components; they must be continuously controlled and monitored to ensure product quality. Spatial control, also known as cross directional (CD) control, is used to maintain uniform product quality in the direction perpendicular to the sheet travel. Existing industrial control technology is based on model predictive control methods, which require solving constrained quadratic optimization problems online for every sampling interval. With the increase in scale and size in these processes and the demand for high product quality, how to robustly solve the optimization problems in face of modeling and disturbance uncertainties and how to tune controller parameters for good closed-loop performance are critical; the challenges include high dimensions of input and output variables involved, active actuator constraints, and short control intervals. Our objectives are to develop, evaluate, and apply advanced methods for cross directional control of large flat sheet processes, addressing robustness and controller tuning in the model predictive control framework; in particular, adopting the model predictive approach, we will investigate existing solutions, develop new algorithms for the robust control design and controller auto-tuning, considering feasibility and closed-loop stability issues and exploring sparse matrix structures in cross directional models, and study their efficient implementation in Honeywell control systems. Honeywell is a main provider of papermaking equiments and associated control systems. Successful completion of this project would enhance Honeywell's control technology for papermaking, benefiting the Canadian pulp and paper industry in general. Also, strong industry-university collaboration would strengthen Honeywell Vancouver's employee retention and attraction programs.