Control Development and Modelling for Enhanced Crystal Growth: Application to Novel New Technologies and Extenstion of Conventional Capabilities

增强晶体生长的控制开发和建模：新技术的应用和传统能力的扩展

• 批准号: 0100310
• 负责人: Michael Gevelber
• 金额: $ 27万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0100310&HistoricalAwards=false
• 关键词: Control; Development; Modelling; Enhanced; Crystal

Characterizing these in terms of the control gain can be misleading. The idea of using feedforward of known effects to assist the feedback control is good, but well known. Micro-level material objectives have been indirectly incorporated in the design of controllers for years. However, the idea of explicitly incorporating the effects of heat flow is a good example of the use of modeling to help determine the controller explicitly. Although adaptive control is proposed as an integral part of both the feedback control and the feedforward control, very little is said about adaptive control per se.I have a few comments on the interpretations of the graphs. The text in Figure 11 states that the oscillation in diameter indicates the need for adaptive control. However, without knowing the measurements that determine both the pull rate and the heater power, and the system dynamics, it is not apparent that adaptive control is required. Certainly, Figure 11 by itself is insufficient. Figure 19 shows oscillations of the boule diameter, which is one indication of nonminimum phase behavior. However, the anomaly near the end of the graph appears to be due to a nonlinear effect (or a time variation). This graph, if the anomalous behavior is not uncommon, would present a good argument for the use of adaptive control.The modeling of the CZ and EMCZ appears to be appropriate. Experimentation to validate the models is reasonable, and I expect that it can be conducted on the available puller.In summary, I think the primary contribution of the proposed effort will be the development of models for the CZ and EMCZ processes. There will be no new contribution to control theory (and the proposal doesn't claim any). Although the proposal states that controllers for these processes will be developed, the analysis of the control issues is weak.

用控制增益来描述这些特性可能会产生误导。使用已知效应的前馈来辅助反馈控制的想法是好的，但众所周知。多年来，微观层面的物质目标一直被间接地纳入控制器的设计中。然而，显式地结合热流效应的想法是使用建模来帮助显式地确定控制器的一个很好的例子。虽然自适应控制被提出作为反馈控制和前馈控制的一个组成部分，但很少有人提到自适应控制本身。图11中的文本指出，直径的振荡表明需要自适应控制。然而，在不知道确定提拉速率和加热器功率两者的测量以及系统动态的情况下，不明显需要自适应控制。当然，图11本身是不够的。图19显示了晶锭直径的振荡，这是非最小相行为的一个指示。然而，曲线图末端附近的异常似乎是由于非线性效应（或时间变化）。如果异常行为并不罕见，则该图将为使用自适应控制提供很好的论据。CZ和EMCZ的建模似乎是适当的。验证模型的实验是合理的，我希望它可以在可用的拉料器上进行。总之，我认为所提出的努力的主要贡献将是CZ和EMCZ过程的模型的开发。对控制理论不会有任何新的贡献（该提案也没有提出任何要求）。虽然该提案指出，这些过程的控制器将被开发，控制问题的分析是薄弱的。