Research Initiation: A Bilevel Programming Methodology for Optimizing Control of Chemical Processes

研究启动：优化化学过程控制的双层编程方法

• 批准号: 8808865
• 负责人: Peter Clark
• 金额: --
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-06-15 至 1990-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8808865&HistoricalAwards=false
• 关键词: Research; Initiation; Bilevel; Programming; Methodology

The objectives of control and operation of industrial processes are set up in a hierarchial mode. Short-term, random, rapid fluctuations are handled by regulators which implement some chosen operating policy and are at the bottom of the control hierarchy. Medium-term transients are the domain of an optimizing layer in the middle of the hierarchy, which produces setpoints to respond to changes in operating policy, process performance and feed quality. Long-term changes are managed by a production planning layer at the top of the hierarchy, which allocates feeds, assigns production rates and determines the best mix of products in response to changing market conditions. Thus, the process is insulated from a failure of a higher layer by the presence of the lower ones, e.g., if the optimizing computer goes down, operation will still continue under the direction of the regulator. These control schemes in the past were designed assuming that the regulator acts much more quickly than the optimizer, so the optimizer can ignore the dynamics of the regulator. The principal goal of this research is to develop a novel optimizing control frame work that explicitly accounts for the interplay between the optimizer and the regulator. Continuing pressures to operate with reduced inventories have caused feedstocks to be purchased in smaller quantities, on an "as needed" basis. If a commodity available from several producers is used as a feed, this introduces a source of significant variations into a process. This higher frequency of feed changes demands more frequent action by the optimizer. However, imposing a more rapid optimizing action on industrial processes with slow dynamics pushes the time scales of the optimizer and regulator closer, making an optimizer which ignores the actions of the regulator inadequate. The proposed approach to account for the interaction between the optimizer and the regulator in such circumstances uses an optimization formulation known as the bilevel program. The PI proposes to develop an efficient algorithm for solving this optimization problem.

工业过程的控制和操作目标以层次模式建立。短期的、随机的、快速的波动由管理者来处理，他们执行一些选定的操作政策，处于控制层次的底层。中期暂态是层次结构中间的优化层的领域，它产生设定值以响应操作策略、过程性能和馈送质量的变化。长期变化由位于层次结构顶端的生产计划层管理，该层负责分配饲料、分配生产率，并根据不断变化的市场条件确定最佳的产品组合。因此，由于存在较低的层，该过程与较高层的故障绝缘，例如，如果优化计算机出现故障，操作仍将在调节器的指导下继续进行。过去这些控制方案的设计假设调节器的动作比优化器快得多，因此优化器可以忽略调节器的动态。本研究的主要目标是开发一种新的优化控制框架，明确说明优化器和调节器之间的相互作用。库存减少的持续压力导致原料采购数量减少，“按需”采购。如果从几个生产者那里获得的一种商品被用作饲料，这就给一个过程引入了一个重大变化的来源。这种更高频率的进料更改要求优化器更频繁地执行操作。然而，对具有缓慢动态的工业过程施加更快速的优化动作会使优化器和调节器的时间尺度更接近，从而使忽略调节器动作的优化器变得不足。在这种情况下，考虑优化器和调节器之间相互作用的建议方法使用一种称为双层程序的优化公式。PI建议开发一种有效的算法来解决这一优化问题。