Intelligent Electronic Leaf Sensor

Abstract An innovative combined sensing method is introduced and developed to replace leaf sensors in plant propagation systems. The basic method relates macroenvironmental factors, used for monitoring the greenhouse environment, to assess the level of suitability of the microclimate of the propagules. It combines ordinary measurements, of ambient temperature, humidity and radiation, to calculate the controls of the humidification process, in mist or fog propagation chambers. The new method is based on the fact that conditions of the microclimate are fully determined by the surrounding space, and implicitly relates the process between the two spaces through the setting of control parameters. These parameters, together with the measured macroclimatic variables, determine the rate of humidity to be added into the chamber. The parameters are initially adjusted by the operator, through his observation and intuition about the suitability of the environment. Subsequently an adaptive system guides the selection of control parameters in a process leading to optimal system performance. The system, tested in a commercial enterprise, assumes at start-up the functions of a software leaf sensor, with fixed parameters and performance that satisfies the user requirements. Simulation tests proved that the system is capable of gradually improving the control parameters by seeking an optimal operating point for each situation. Critical to the success of the optimizing system, for refining the controlled process in the real world, is the establishment of proper performance criteria, used by the system for self-evaluation.