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

在造纸中，平板工艺是一个具有空间和动态组件的大规模二维系统;必须对它们进行连续控制和监测，以确保产品质量。空间控制，也称为横向（CD）控制，用于在垂直于片材行进的方向上保持均匀的产品质量。现有的工业控制技术是基于模型预测控制方法，它需要在线求解每个采样间隔的约束二次优化问题。随着这些过程的规模和尺寸的增加以及对高产品质量的需求，如何鲁棒地解决面对建模和干扰不确定性的优化问题以及如何调整控制器参数以获得良好的闭环性能是至关重要的;所面临的挑战包括涉及的输入和输出变量的高维数、主动执行器约束以及短的控制间隔。 我们的目标是开发，评估和应用先进的方法，用于大型平板过程的横向控制，解决模型预测控制框架中的鲁棒性和控制器整定问题;特别地，采用模型预测方法，我们将研究现有的解决方案，开发用于鲁棒控制设计和控制器自动整定的新算法，考虑可行性和闭环稳定性问题，探索交叉方向模型中的稀疏矩阵结构，并研究其在Honeywell控制系统中的有效实现。 霍尼韦尔是造纸设备和相关控制系统的主要供应商。成功 该项目的完成将提高霍尼韦尔的造纸控制技术，使加拿大的纸浆和造纸工业普遍受益。此外，强有力的行业和大学合作将加强霍尼韦尔温哥华的员工保留和吸引力计划。

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.