Temperature and humidity control method of artificial climate box

Temperature and humidity control method of artificial climate box

The artificial climate box, like the light box, can provide a simulated natural environment, such as suitable temperature, humidity, light intensity, etc., to provide a necessary environment for plant growth. In addition, the various parameters of the artificial climate box can be freely set manually, eliminating the uncontrollable annoyance of the natural environment. Temperature and humidity control is the most favorable weapon for the artificial climate chamber system. At the same time of temperature and humidity control, we can use the temperature and humidity self-recording apparatus to measure and keep abreast of the temperature and humidity changes in the artificial climate chamber.

When the temperature is low and the water is heated, the moisture evaporates. The previously cooled or dehumidified condensed moisture in the climate chamber will evaporate and increase the internal humidity. When the temperature is high and the cooling is performed, the humidity of the airflow passing through the refrigerator will be reduced to make the whole box. Humidity of the body decreases; similarly when the humidity is low and the humidity is humid, external cold or hot moisture will change the internal temperature, and high humidity and dehumidification will inevitably lead to a drop in temperature. So the control of temperature and humidity is strongly coupled. In addition, the coupling degree of the temperature and humidity of the box of different specifications is different. In addition, climate chambers require temperature and humidity multi-stage circulation control. The temperature and humidity in the two stages are different. The mathematical model of temperature and humidity control in the climate chamber also indicates that they have large hysteresis characteristics and must achieve rapid rise and transition times. Short-term and over-adjusted purposes, the general control method is difficult to work.

From the above analysis, it can be seen that the control of the temperature and humidity of the climate chamber is coupled with each other. In this way, the control of temperature and humidity is essentially a control problem of a large lagging, strongly coupled system. These characteristics determine that it is difficult to obtain high accuracy in temperature and humidity control. General artificial climate chamber uses separate temperature controllers and humidity controllers to achieve temperature and humidity control, and most of their control methods are PID control methods. The effect of time-varying system control for purely lagging parameters is not ideal, and they are used. It is also inconvenient, and the fuzzy controller is independent of the system's mathematical model, eliminating the need to identify the system, has good robustness and adaptability, and is suitable for control occasions such as model uncertainties and parameter changes. It can just adapt to the temperature and humidity control of the artificial climate box, so the controller of the artificial climate box adopts a fuzzy control method to control the temperature and humidity of the box air flow, and also uses the fuzzy decoupling method to solve the problem of strong temperature and humidity coupling.