The roll-to-roll (R2R) web printing system is a complex coupling system, in which tension fluctuation is caused by upstream register control, thus results in downstream register errors. Therefore, it is indispensable to compensate for the couplings in order to improve the register precision in R2R printing systems. However, existing control methods do not realize complete decoupling due to their indirect calculation of compensations for the register errors. In this article, a mechanical model is set up to represent the direct relationship between the downstream register errors and all their upstream register controls. According to the model, compensation is calculated on the basis of the Lyapunov stability theorem to converge the register errors to zero. Then, a direct-decoupling closed-loop control method with first-order compensation terms, i.e., the direct-decoupling proportional derivative control (DDPD), is proposed to completely compensate for the couplings between all upstream register controls and downstream register errors. In addition, the first-order expression of the compensation makes it easy to implement in industrial applications. An industrial example indicates that the proposed control method eliminates the couplings and maintains the range of register errors within ±0.06 mm. Note to Practitioners —This article proposes a control strategy for the roll-to-roll (R2R) printing system, particularly for printing systems with electronic line shafts. Few existing studies have been done in detailedly analyzing the upstream register controls and the downstream register errors. This article establishes a mechanical model of printing registration and gives a systematic analysis of the complete relationship between upstream register controls and downstream register errors and then proposes a control strategy based on the Lyapunov stability analysis. The proposed method can be extended to other similar R2R systems. Simulation and industrial examples show that the control method is more feasible and effective compared with the existing methods. In future work, we will study a control method combined with the mechanical model and data model in different R2R systems.

中文翻译：

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卷对卷卷筒纸印刷系统的直接解耦闭环控制方法


卷对卷(R2R)卷筒纸印刷系统是一个复杂的耦合系统，其中上游套准控制引起张力波动，从而导致下游套准误差。因此，为了提高R2R印刷系统的套准精度，必须对联轴器进行补偿。然而，现有的控制方法由于对套准误差补偿的间接计算，未能实现完全的解耦。在本文中，建立了一个机械模型来表示下游套准误差与其所有上游套准控制之间的直接关系。根据该模型，根据李亚普诺夫稳定性定理计算补偿，使套准误差收敛为零。然后，提出了一种具有一阶补偿项的直接解耦闭环控制方法，即直接解耦比例微分控制（DDPD），以完全补偿所有上游套准控制与下游套准误差之间的耦合。此外，补偿的一阶表达式使其易于在工业应用中实现。工业实例表明，所提出的控制方法消除了耦合，并将套准误差范围保持在±0.06 mm之内。从业者须知——本文提出了一种卷对卷（R2R）打印系统的控制策略，特别是带有电子线轴的打印系统。现有的研究很少详细分析上游套准控制和下游套准错误。 本文建立了印刷套准的力学模型，系统分析了上游套准控制与下游套准误差之间的完整关系，提出了基于李亚普诺夫稳定性分析的控制策略。所提出的方法可以扩展到其他类似的 R2R 系统。仿真和工业实例表明该控制方法与现有方法相比更加可行和有效。在未来的工作中，我们将研究不同R2R系统中机械模型和数据模型相结合的控制方法。