Internal model control (IMC) of a fruit drying system

Geddes, Scott A. (2006) Internal model control (IMC) of a fruit drying system. [USQ Project] (Unpublished)


Download (513Kb)


The use of automation within the food processing industry, has allowed for the
continual improvement in production and quality control, including that for dried
fruit products.
By monitoring and controlling process variables within a commercial fruit dryer
(dehydrator), quality control features such as moisture-content, texture, and
colour etc, can be attained. The three minimum process variables within most
commercial fruit dryers to achieve successful drying are air-temperature,
air-velocity, and relative-humidity.
This project investigates the control of air-temperature in a fruit dehydrator by
firstly implementing a PID controller. Then as a separate exercise, an IMC
controller is implemented, and a performance comparison between the PID and
IMC controllers was conducted.
The PID controller was initially designed using the Ziegler-Nichols (step response
method), but was determined to be too inaccurate for this purpose. So
optimization using Steepest Descent Minimization was also used to determine
the PID controller gains.
IMC being considered a robust adaptive controller [6], is especially suited to this
plant, having both a large time-constant and transport-delay.
Theoretically IMC can always provide perfect system stability if the open-loop
plant is first determined to be stable and an exact model of the plant is maintained,
further allowing the designer to adjust other filter parameters without effecting

Statistics for USQ ePrint 2465
Statistics for this ePrint Item
Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Depositing User: epEditor USQ
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Electrical, Electronic and Computer Engineering
Date Deposited: 11 Oct 2007 01:07
Last Modified: 02 Jul 2013 22:44
Uncontrolled Keywords: internal model control (IMC); fruit; drying system; PID; dehydration
Fields of Research (FoR): 09 Engineering > 0913 Mechanical Engineering > 091302 Automation and Control Engineering
10 Technology > 1006 Computer Hardware > 100699 Computer Hardware not elsewhere classified

Actions (login required)

View Item Archive Repository Staff Only