| The Stein Lab Oven is an air impingement oven used for research at the University of Arkansas on the elimination of pathogens such as Salmonella, Listeria monocytogenes and Escherichia coli from ready-to-eat beef and poultry products. This oven allows for control over cooking time, cooking temperature, humidity and airflow. During research the oven is operated at desired constant temperature, humidity and airflow values, but the temperature and humidity values deviate from the desired values when disturbances occur, such as when raw product is brought into the oven.;A fuzzy logic control system is developed to maintain constant temperature and humidity values and quickly recover from disturbances to the oven. A model of the oven is developed in Matlab to facilitate the modeling, design, testing and verification of the fuzzy logic controller in Matlab. The controller design is ported to the Freescale 68HCS12 microcontroller and that implementation is tested and verified against the oven model in Matlab using analog and digital input and output signals through a data acquisition card. The results of this effort show that a control system can be developed for a multiple input, multiple output plant with non-linearly independent variables using only recorded data and observations on the behavior of the plant. The results show that a fuzzy logic controller can be implemented on an external hardware platform and tested against a model in Matlab through a data acquisition card. The results of this effort can be extended to the control of any plant model in Matlab by any control system implemented on an external microcontroller, provided that the inputs and outputs of each system can be implemented as analog and/or digital signals. |
