Limits of control performance: a model-based approach

控制性能的限制：基于模型的方法

• 批准号: 3522-2007
• 负责人: Shah, SirishLalji
• 金额: $ 3.02万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=361464
• 关键词: Limits; control; performance; model; based

Basic control has matured to the point where many advanced control algorithms are now standard products in most DCS systems. For many critical loops it is desired to obtain the highest level of control performance given a specific type of control strategy, e.g. Proportional, Integral and Derivative (PID) or Model-based Predictive Control (MPC). Such fundamental limits to control performance are due to specific process, actuator and sensor characteristics and can be expressed in terms of the bounds due to Bode's integral theorem on the sensitivity and complementary sensitivity functions. An understanding of these types of factors and their impact on the performance that can be attained with a 'well designed' controller are important factors and can most easily be described if the process model is known.Therefore the specific focus of this research proposal will be to explore the limits of control performance from a model-based perspective, unlike the historical data-based perspective. The data-based performance monitoring approach is now well established and its focus has been on computing performance metrics from routine process data and comparing them to a benchmark, for example the minimum variance benchmark or other used-specified benchmarks.  The topic of the best achievable control given some knowledge of the process dynamics and controller type, for example a PI(D) controller, will be the main focus of this research proposal.Over 90% of the controllers used in industry are (PID) type and yet the issue of the best achievable PI(D) control for a given class of first order plus time-delay or a second order plus time-delay process is an open problem. This proposal is to explore these fundamental limitations of PI(D) controllers when applied to the most common industrial processes.

基本控制已经成熟到许多先进的控制算法现在是大多数集散控制系统的标准产品。对于许多关键回路，人们希望在给定特定类型的控制策略的情况下获得最高水平的控制性能，例如比例、积分和微分(PID)或基于模型的预测控制(MPC)。这种对控制性能的基本限制是由于特定的过程、执行器和传感器的特性，并且可以用Bode关于灵敏度和互补灵敏度函数的积分定理的界限来表示。了解这些类型的因素及其对性能的影响是重要的因素，如果过程模型已知，则可以最容易地描述这些因素。因此，与基于历史数据的观点不同，本研究方案的具体重点将是从基于模型的角度探索控制性能的极限。基于数据的性能监控方法现在已经很成熟，它的重点是从常规过程数据计算性能度量，并将它们与基准进行比较，例如最小方差基准或其他使用指定的基准。在给定一些过程动力学和控制器类型的知识的情况下，最佳可实现控制的主题，例如PI(D)控制器，工业上使用的控制器中90%以上是(PID)型的，然而对于给定的一阶加时滞或二阶加时滞过程的最佳可实现PI(D)控制的问题是一个开放的问题。本提案旨在探讨PI(D)控制器在应用于最常见的工业过程时的基本局限性。