FEEDBACK CONTROL OF PARTICLES IN FLUID MEDIA

流体介质中颗粒的反馈控制

• 批准号: 2277806
• 负责人: DAVID R. HEMENWAY
• 金额: $ 3.65万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2277806
• 关键词: aerosols; air sampling /monitoring; biomedical equipment development; computer system design /evaluation; controlled environment chamber; dust; environmental air flow measurement; fluidity; mathematical model; monitoring device; particle

With the development of accurate real-time monitors to measure aerosol and gas concentrations, the potential exists for the development of a feedback control system to automatically manipulate building ventilation rates in relation to contaminant levels. The proposed studies are concerned with the development of such a system with the use of an animal inhalation chamber. This device will allow for a controlled setting in which contaminant concentration and flow rate can be maintained at predetermined levels. The specific aims of this study will be to investigate (l) the response of chamber concentration levels of cristobalite to various changes in dust generator speed and air flow rate and, (2) the use of statistical process control (SPC) techniques to implement feedback control of the concentration. Preliminary studies have been conducted to develop devices to automated the production of cristobalite with a computer controlled dust feed and chamber air valve actuator. This system has proven to be capable of producing and maintaining a chamber concentration level equivalent to a desired value chosen by the operator. The proposed studies will expand this system to incorporate feedback control based on information sent to the computer from a real-time aerosol monitor. We hypothesize the main difficulties to be overcome in the development of this system include: inconsistent response of the concentration level to a change in generator speed or flow rate and, a need to accurately predict the mean level of the chamber concentration when the reading exhibit a high degree of instantaneous variation. We will attempt to use an SPC technique known as an exponentially weighted moving average (EWMA) to both indicate the mean level and provide statistically derived control limits about the EWMA derived value to buffer the control system from spikes in the monitor readings which may cause an over-reaction of the control system. Results from this study will have immediate implications to the field of inhalation toxicology where strict control of chamber conCentration levels is important to results of dose- response relationships. We believe this information may also be of use to industrial hygienists involved with ventilation systems which use dilution air to control contaminant levels-in factories, mines and office buildings.

随着准确的实时监测器的开发以测量气雾剂 和气体浓度，存在的潜力是 反馈控制系统自动操纵建筑物 与污染物水平有关的通风率。 提议 研究涉及与此系统的发展 使用动物吸入室。该设备将允许 污染物浓度和流速的受控设置可以 保持在预定水平。这项研究的具体目的 将研究（l）腔室浓度水平的响应 粉尘发生器速度和气流的各种变化的cristobalite 速率和（2）使用统计过程控制（SPC）技术 实施集中度的反馈控制。初步研究 已经进行了开发设备以使生产的生产自动化 带有计算机控制的尘埃饲料和室内气阀的cristobalite 执行器。 事实证明，该系统能够生产和 保持腔室浓度水平等效于期望的值 由操作员选择。拟议的研究将扩大该系统 根据发送给该信息的信息来合并反馈控制 实时气溶胶监视器的计算机。我们假设主要 在该系统的开发中克服的困难包括： 浓度水平对变化的反应不一致 发电机的速度或流速，并且需要准确预测平均值 当阅读表现出高度时，腔室浓度的水平 瞬时变化程度。 我们将尝试使用SPC 被称为指数加权的移动平均值（EWMA）的技术 两者都表示平均水平并提供统计得出的控制 关于EWMA衍生值的限制以缓冲控制系统 监视器读数中的尖峰可能会导致过度反应 控制系统。 这项研究的结果将立即 对严格控制的吸入毒理学领域的影响 腔室浓度水平的水平对剂量的结果很重要 响应关系。 我们认为这些信息也可能有用 到参与使用通风系统的工业卫生学家 稀释空气以控制污染物的工厂，地雷和 办公楼。