Control Loop Performance Diagnosis in the Presence of Uncertainties

过程控制系统至关重要，因为它们允许稳定和安全的过程操作、一致的产品质量、更少的浪费和更好的排放控制。但控制系统的性能可能会随着时间的推移而恶化，原因是仪器的磨损、进料或产品等级的变化以及过程动态和操作环境的变化。及时诊断性能恶化的根源是保持最佳性能的关键。 有效的性能诊断面临的主要挑战来自随机不确定性、认知不确定性、监控离散化不确定性以及历史特征数据的缺乏。该方案的目的是建立一个通用的控制回路性能诊断框架，以解决上述问题。我们提出的方法是基于证据理论，特别是Dempster-Shafer理论，以及使用连续的性能监控输出。还考虑了与实际工程应用相关的问题，并将在统一的框架下解决这些问题。这些解决方案将通过中试实验和工业应用进行评估。我们的长期目标是建立一个集成的控制器资产咨询系统，包括控制性能监测、控制回路性能诊断和决策，以便在考虑经济性、过程约束和环境影响的情况下对过程控制系统进行优化。 我们的研究将为鲁棒控制回路性能诊断奠定理论和方法基础。我们提出的解决方案将适用于广泛的行业。通过让学生参与这项工作的各个方面，我们的研究计划将培养与加拿大工业高度相关的控制、监测和诊断领域的高素质人才。

Process control systems are critical because they allow for steady and safe process operations, consistent product quality, less waste, and better control of emissions. But the performance of control systems can deteriorate over time due to wear of instruments, variation of feed or product grade, and change of process dynamics and operating environment. Timely diagnosis for detection of the sources of performance deterioration is critical to maintenance of optimal performance. The main challenges to effective performance diagnosis come from stochastic uncertainty, epistemic uncertainty, monitor discretization uncertainty, and lack of historical feature data. The objective of this proposal is to build a general framework for control loop performance diagnosis to solve all the above issues. Our proposed methodology is based on evidence theory, specifically Dempster-Shafer theory, along with the use of continuous performance monitor outputs. Problems associated with practical engineering applications are also considered and will be solved under a unified framework. The solutions will be evaluated by pilot-scale experiments as well as by industrial applications. Our long-term goal is to establish an integrated controller asset advisory system that consists of control performance monitoring, control loop performance diagnosis, and decision making, so that process control system can be optimized with considerations such as economics, process constraints, and environmental impacts. Our research will establish a theoretical and methodological foundation for robust control loop performance diagnosis. Our proposed solutions will be applicable to a wide range of industries. By involving students in all aspects of this work, our research program will train personnel who are highly qualified in control, monitoring and diagnosis - areas that are highly relevant to Canadian industry.