Hosseini Marzieh, Kaasinen Anna, Aliyari Shoorehdeli Mahdi, Link Guido, Lähivaara Timo, Vauhkonen Marko
Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland.
Mechatronics Department, Electrical Engineering Faculty, K.N. Toosi University of Technology, Tehran 16315-1355, Iran.
Sensors (Basel). 2021 Oct 28;21(21):7170. doi: 10.3390/s21217170.
The microwave drying process has a wide application in industry, including drying polymer foams after the impregnation process for sealings in the construction industry. The objective of the drying process is to reach a certain moisture in the foam by adjusting the power levels of the microwave sources. A moisture controller can be designed to achieve this goal; however, a process model is required to design model-based controllers. Since complex physics governs the microwave drying process, system identification tools are employed in this paper to exploit the process input and output information and find a simplified yet accurate model of the process. The moisture content of the foam that is the process output is measured using a designed electrical capacitance tomography (ECT) sensor. The ECT sensor estimates the 2D permittivity distribution of moving foams, which correlates with the foam moisture. Experiments are conducted to collect the ECT measurements while giving different inputs to the microwave sources. A state-space model is estimated using one of the collected datasets and is validated using the other datasets. The comparison between the model response and the actual measurements shows that the model is accurate enough to design a controller for the microwave drying process.
微波干燥过程在工业中有广泛应用，包括在建筑业中对密封件进行浸渍处理后干燥聚合物泡沫。干燥过程的目标是通过调整微波源的功率水平使泡沫达到一定的含水量。可以设计一个湿度控制器来实现这一目标；然而，设计基于模型的控制器需要一个过程模型。由于复杂的物理原理支配着微波干燥过程，本文采用系统辨识工具来利用过程的输入和输出信息，找到一个简化但准确的过程模型。作为过程输出的泡沫含水量通过设计的电容层析成像（ECT）传感器进行测量。ECT传感器估计移动泡沫的二维介电常数分布，该分布与泡沫含水量相关。在给微波源不同输入的同时进行实验以收集ECT测量数据。使用其中一个收集到的数据集估计状态空间模型，并使用其他数据集进行验证。模型响应与实际测量值之间的比较表明，该模型足够准确，可以为微波干燥过程设计控制器。
