Modelling and control of a forward roll coater
Lind, Simon (2022)
Lind, Simon
2022
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2022021619341
https://urn.fi/URN:NBN:fi-fe2022021619341
Tiivistelmä
A roll coater applies a coating to a substrate by two or more rotating rolls. The studied case is a 3-roll forward roll coating system. The system's main objective is to apply the base coating to sandpaper. This is done by having the paper rest on a web that travels through the web and application roller. The continuous web lays on the web roller, and the coating is present on the application roller. The distance between the rollers is called the gap and will be one of the main controlling variables in managing that the correct amount of coating is applied to the paper. There are two different kinds of gaps present, one between the web and application roller and one between the metering and application roller. The one between the metering and application roller is controlling that the right amount of coating is applied to the application roller. This gap is usually run with a negative distance, meaning that the rolls are pressed together. The outer layer of the application roller is made out of deformable material to ensure that the rolls do not clash. The system is in a fully flooded regime when the gap between the web and application roller is filled with coating, and a rolling bank is present before the gap. Reducing the amount of coating in the gap will make the bank disappear, and the system will be in a starved configuration. The data for the system is collected by a sensor moving back and forth across the web’s width direction.
A feedback control system is built for the coating system in Simulink. The primary control variables are the gaps between the rolls and the speed of the metering roll. A line approximation is added to represent the geometry of the rollers. An estimator is used to ensure that data is available when the sensor is not present. The model seems to fit well when comparing simulated results to data from the plant.
A feedback control system is built for the coating system in Simulink. The primary control variables are the gaps between the rolls and the speed of the metering roll. A line approximation is added to represent the geometry of the rollers. An estimator is used to ensure that data is available when the sensor is not present. The model seems to fit well when comparing simulated results to data from the plant.