Control of Screw Extruder Delay/Partial Differential Equation (PDE) Dynamics for 3D Printing

3D 打印螺杆挤出机延迟/偏微分方程 (PDE) 动力学控制

• 批准号: 1562366
• 负责人: Miroslav Krstic
• 金额: $ 32.66万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1562366&HistoricalAwards=false
• 关键词: Control; Screw; Extruder; Delay; Partial

Motivated by both the potential for a technological, economic, and social impact of additive manufacturing, the project is dedicated to the design of controllers to remove some of the key bottlenecks to achieving high speed and product quality in 3D printing. The project will build control and modeling methodologies that are both of high research value and are suitable for industrial use, going after improvements in the build speed and part quality. Compared to the standard Fused Deposition Modeling and Syringe Based extrusion processes, the novel configuration of the Screw Extruder process that we address may allow continuous feeding, speed up production, and upgrade the mixing capabilities, while efficiently reducing the thermal degradation of the melt and the cost for such processes. The PI has supervised two dozen students from underrepresented groups on past projects, such as women, Hispanics, and African-Americans, and the present project will involve specific individuals from underserved communities as advisees and collaborators. Partial Differential Equation (PDE) models of mass and thermal flows in the Screw Extruder will be used to design accurate and robust controllers, to replace the existing control methods for 3D printing, which are typically constructed using conservative black-box or lumped models, which reduces their performance for a large range of materials. Moreover, control of the melt thermal behavior that impacts viscosity evolution and the solidification process will be addressed. The control design will be based on infinite-dimensional models of screw extruders, including a bi-zone model consisting of PDEs coupled through a moving interface described by an ordinary differential equation. Novel control design techniques from the PI's infinite-dimensional backstepping toolkit will be developed for this purpose. Implementation of the designed controller will be performed on an experimental platform developed in the PI's group. The project will provide advancements to the general area of control of PDEs that are coupled through a moving interface, which, besides extruders, arise in multi-phase flows, crystal growth, freeze-drying, and distillation processes.

受增材制造的技术、经济和社会影响潜力的推动，该项目致力于设计控制器，以消除3D打印中实现高速和产品质量的一些关键瓶颈。该项目将建立控制和建模方法，既具有很高的研究价值，又适合工业使用，追求提高构建速度和零件质量。与标准的熔融沉积成型和基于注射器的挤出工艺相比，我们提出的螺杆挤出机工艺的新配置可以允许连续进料，加快生产速度，并提升混合能力，同时有效地降低熔体的热降解和此类工艺的成本。PI在过去的项目中监督了来自代表性不足的群体的24名学生，如妇女、西班牙裔和非洲裔美国人，本项目将涉及来自服务不足社区的特定个人作为参与者和合作者。螺杆挤出机中质量和热流的偏微分方程（PDE）模型将用于设计精确和鲁棒的控制器，以取代现有的3D打印控制方法，这些方法通常使用保守的黑盒或集总模型构建，这会降低它们对大范围材料的性能。此外，熔体的热行为，影响粘度演变和固化过程的控制将得到解决。控制设计将基于螺杆挤出机的无限维模型，包括由通过常微分方程描述的移动界面耦合的PDE组成的双区模型。新的控制设计技术，从PI的无穷维反推工具包将开发用于此目的。所设计的控制器的实施将在PI组开发的实验平台上进行。该项目将为通过移动界面耦合的偏微分方程的一般控制领域提供进步，除了挤出机之外，偏微分方程还出现在多相流动、晶体生长、冷冻干燥和蒸馏过程中。