In this work, we investigate the effects of various types of valve behavior (e.g., linear valve dynamics and stiction) on the effectiveness of process control in a unified framework based on systems of nonlinear ordinary differential equations that characterize the dynamics of closed-loop systems including the process, valve, and controller dynamics. By analyzing the resulting dynamic models, we demonstrate that the responses of the valve output and process states when valve behavior cannot be neglected (e.g., stiction-induced oscillations in measured process outputs) are closed-loop effects that can be difficult to predict a priori due to the coupled and typically nonlinear dynamics of the process-valve model. Subsequently, we discuss the implications of this closed-loop perspective on the effects of valve dynamics in closed-loop systems for understanding valve behavior compensation techniques and developing new ones. We conclude that model-based feedback control designs that can account for process and valve constraints and dynamics provide a systematic method for handling the multivariable interactions in a process-valve system, where the models in such control designs can come either from first-principles or empirical modeling techniques. The analysis also demonstrates the necessity of accounting for valve behavior when designing a control system due to the potentially different consequences under various control methodologies of having different types of valve behavior in the loop. Throughout the work, a level control example and a continuous stirred tank reactor example are used to illustrate the developments.

在这项工作中，我们研究了基于非线性常微分方程组系统的，以表征闭环系统动力学为特征的各种阀行为（例如，线性阀动力学和静摩擦）在统一框架中对过程控制有效性的影响。包括过程，阀门和控制器动力学。通过分析所得的动力学模型，我们证明了当无法忽略阀行为时（例如，在测量的过程输出中静摩擦引起的振荡）时，阀输出和过程状态的响应是闭环效应，可能很难先验地预测。归因于过程阀模型的耦合动力学（通常是非线性动力学）。随后，我们讨论了这种闭环观点对闭环系统中阀门动力学影响的意义，以了解阀门行为补偿技术并开发新技术。我们得出结论，基于模型的反馈控制设计可以解决过程和阀门的约束以及动态特性，为处理过程阀系统中的多变量相互作用提供了一种系统的方法，其中此类控制设计中的模型可以来自第一性原理，也可以来自第一性原理或第二性原理。经验建模技术。分析还表明，在设计控制系统时，有必要考虑阀的性能，这是由于在各种控制方法下，回路中具有不同类型的阀性能可能会产生不同的后果。在整个工作中，使用液位控制示例和连续搅拌釜反应器示例来说明开发情况。