Comparison of Classical and Optimal Control of Greenhouse Tomato Crop Production

Abstract

Through simulation, the optimal control of tomato crop production in a greenhouse based on an economic criterion, is compared with the result obtained with a conventional classical controller. The result is 6 % increase in profit and 43 % increase in energy efficiency over a characteristic autumn day. The solution of the optimal control problem is not at all straightforward. The greenhouse-tomato system is stiff. Singular perturbation theory is usually applied to cope with stiffness in optimal control problems, but in this case direct application is problematic due to the rapid external disturbances. In this paper the problem is solved by adapting a method proposed earlier by Van Henten (1994).