Multi-variable Interval Control Method for Greenhouse Environment System

Abstract

The invention relates to a multivariable interval control method for a greenhouse environment system, is mainly applied to a multivariable control system for greenhouse production and replaces a traditional point control target with an interval control target through relaxing target control precision of environment factors. The method comprises steps that 1), controller parameters are initiated, and greenhouse environment factor control target intervals are set; 2), the environment factors such as indoor humiture and CO2 concentration are acquired through a sensor; 3), the acquired environment factors are compared with those of a controlled target control interval, and control deviation can be acquired by employing a control deviation processing algorithm; and 4), feedback control is carried out by the controller according to control deviation, the larger control deviation, the stronger the control effect is, through adjustment carried out by an actuating structure, the greenhouse environment multivariable interval control target is realized. According to the method, not only can a problem of no-solution limit caused by strong coupling among the factors of the greenhouse environment be effectively solved, but also wide freedom is provided for controller economy optimization.

Description

technical field [0001] The invention relates to a multi-variable interval control method for a greenhouse environment system, in particular to a multi-variable interval control method for a greenhouse environment by relaxing the target control accuracy of environmental factors and replacing the traditional "point" control target with an "interval" control target. Background technique [0002] At present, most of the control strategies of the greenhouse environment still adopt a strict set-point precise control mode. For example, the temperature control mode generally maintains a fixed temperature set-point in the morning and evening. This applies the traditional fixed-set-point control mode. This will cause two problems: [0003] (1) Precise control often leads to a large amount of energy consumption and a sharp increase in production costs, because the energy consumption of the greenhouse is related to the control accuracy of various environmental factors in the greenhouse,...

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Problems solved by technology

[0004] (2) Due to the complexity of the greenhouse environment system, there are many disturbances, constraints, and strong coupling between environmental factors, such as: greenhouse environmental factors (temperature, humidity, light, etc.) Affected by climate change outside the greenhouse and crop photosynthesis (such as transpiration) in the greenhouse, at the same time, the increase in indoor temperature and CO2 concentration will be accompanied by a decrease in relative humidity and an increase in photosynthesis. Precise control can easily lead to a situation where a certain factor reaches the target accuracy requirements, while other targets fail to reach or not fully reach the target accuracy, that is, while the feasible solution (ie, the controller) of the control target of each environmental factor cannot be guaranteed. Existence

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