USING THE EXTENDED KALMAN FILTER TO IMPROVE THE EFFICIENCY OF GREENHOUSE CLIMATE CONTROL

The efficiency of plant production in greenhouses relies on the measurements provided by several electronic sensors located inside and outside the greenhouse. Environmental conditions such as the direct exposure of sensors to sunlight and the deterioration of connections between sensors and the controllers could result in very noisy and incomplete measurements which may impair the greenhouse operation. It may also increase the number of false alarms received from fault detection and isolation (FDI) systems and reduce its detection capability which, in turn, may result in significant financial losses to the grower. The objective of this paper is to explore the ability of the Extended Kalman Filter (EKF) for improving the efficiency of the greenhouse climate controller by using the on-line estimated air temperature and humidity ratio inside the greenhouse as the controlled variables instead of the observed noisy states. The result suggests that the EKF is able to improve the efficiency of the greenhouse climate control and also increase the sensitivity of failure detectability. This approach is not limited to greenhouses but it is also applicable to any control system installed in a noisy environment.