H.-J. Tantau
This paper has been presented as an introduction to the poster session and group discussion about on-line control. Greenhouse climate control can be described as a multi-level control system.

On the first level the control of the greenhouse climate is carried out using feedback and feedforward control. The combination of feedback and feedforward control will increase the stability of the control loop and the accuracy of control.

On the second level an on-line optimization of greenhouse climate control is carried out. For the optimizing algorithms models are necessary. These models must be able to describe the reaction of plants or plant growth to changing environmental factors and the influence on production costs.

On the third level the production planning is done off-line. As an output of the third level, decisionrules and set-points for plantproduction are transferred to the second level. The output of the second level are set-points for the feedback-feedforward control of the greenhouse climate. This hierachical system is completed by expert systems. Expert systems have the advantage that heuristic knowledge basing on experience can be used.

Tantau, H.-J. (1989). ON-LINE CLIMATE CONTROL. Acta Hortic. 248, 217-222
DOI: 10.17660/ActaHortic.1989.248.26

Acta Horticulturae