Modelling and control of forced ventilation in agricultural livestock buildings.

Work carried out for this paper involves the measurement of ventilation rate through a specially designed (test installation) chamber (2.8m3), with a 45cm diameter fan at either end. Ventilation rate is measured via a unique rotary impeller designed in Leuven. Pressure and temperature are also recorded. The test installation has been designed and built in order to develop and evaluate new control algorithms for regulating the airflow rate, and to study the dynamic influence of pressure changes that act as a disturbance on the ventilation rate generated by the fans. The test installation has been built at the Laboratory for Agricultural Buildings Research, Leuven University, Belgium. A series of step input experiments, with varying degrees of disturbance were carried out in order to identify and estimate a transfer function (TF) model of the system using the Simplified Refined Instrumental Variable (SRIV) algorithm. The average control model obtained in this manner is utilised in the development of a Proportional-Integral-Plus (PIP) control system. Finally, Monte Carlo analysis is employed to demonstrate the robustness of the controller over most of the operating regime.