A Novel Model-Based Controller for Polymer Extrusion
A Novel Model-Based Controller for Polymer Extrusion
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DOI：
10.1109/tfuzz.2013.2293348
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发表时间：
2014-01
影响因子：
11.9
通讯作者：
C. Abeykoon
中科院分区：
文献类型：
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作者：
C. Abeykoon
挤出是加工聚合物材料的基本技术，而加工熔体输出的热均匀性是高质量挤出产品的主要关注点。因此，准确的过程热监测和控制对于产品质量控制非常有价值。然而，大多数工业挤出机使用传统的热电偶，其测量仅限于单点，并且受机筒金属壁温度的影响很大。研究表明，熔体温度随模具径向位置变化很大，因此，基于点的测量不足以确定整个熔体流的实际热稳定性。因此，基于这种点/整体测量的热控制技术可能在性能上受到限制。此外，大多数过程热控制方法都是基于线性模型，无法处理过程非线性。在这项研究中，回顾了与挤出机熔体温度控制相关的先前工作，同时确定了它们的局限性。然后提出了一种基于模型的新型控制方法，结合熔体温度分布预测软传感器和模糊逻辑来控制聚合物挤出过程。结果表明，所提出的控制器能够很好地实现熔体流中所需的平均熔体温度，同时最大限度地减少熔体温度变化。控制器对操纵变量所做的调整证实了它有能力根据遇到的不同情况调整合适的变量。因此，这将是当前行业中常见的线性控制技术和基于点/体热测量的控制技术的有前途的替代方案。
Extrusion is a fundamental technique of processing polymeric materials, and the thermal homogeneity of the process melt output is a major concern for high-quality extruded products. Therefore, accurate process thermal monitoring and control are highly invaluable for product quality control. However, most of the industrial extruders use conventional thermocouples whose measurements are limited to a single point and are highly influenced by barrel metal wall temperature. It has shown that the melt temperature varies considerably with the die radial position, and hence, point-based measurements are not sufficient to determine the actual thermal stability across the melt flow. Therefore, thermal control techniques based on such point/bulk measurements may be limited in performance. In addition, the majority of process thermal control methods are based on linear models and are not capable of dealing with process nonlinearities. In this study, a review of the previous work relating to extruder melt temperature control is presented while identifying their limitations. A novel model-based control approach is then proposed to control the polymer extrusion process incorporating a melt temperature profile prediction soft sensor and fuzzy logic. The results show that the proposed controller is good in achieving the desired average melt temperature across the melt flow while minimizing the melt temperature variance. The adjustments made by the controller to the manipulated variables confirmed that it has the capability of adjusting the suitable variables, depending on the different situations encountered. Therefore, this will be a promising alternative to linear control techniques and control techniques based on point/bulk thermal measurements which are common in the present industry.