Research On Intelligent Greenhouse Remote Control System Based On Fuzzy Control Strategy

In recent years, along with the rapid development of computertechnology、automation technology and network technology, the greenhouse environmentcontrol is also developing towards the direction of intelligence and networking, and cropcultivation and management also begins to pay attention to energy saving andsustainable development. In Jilin area, winter is long and cold, summer is short and warm,temperature difference between day and night is large and the basic temperature andtemperature difference compared with other area are quite different. The existing controlsystem is fixed and can’t be changed along the different request of user and seasonalchange.This study aimed at the characteristics of Jilin province located in the north cold area,studied the greenhouse crop growth rhythm、control strategy and the design of softwareand hardware, designed a remote greenhouse intelligent control system to provideappropriate growth environment for greenhouse crop growth, so as to improve cropquality, yield and save energy by adjusting the greenhouse environment, such astemperature, humidity, light and CO2concentration.A fuzzy PID controller of greenhouse control system was designed, the bottomwidth and fuzzy control rules of fuzzy PID controller of two inputs and three outputs hasbeen optimized by improved genetic algorithm. A simulation experiment of the optimizedfuzzy PID controller is made, and compared with conventional PID controller and fuzzyPID controller.The dependence of conventional PID controller on the mathematical model ofcontrolled object is large which leads to some problems such as slow response, largeamount of overshoot, etc. Using fuzzy inference to adjust three parameters of PIDcontroller ΔKp,Δ Ki, ΔKd, the control effect is superior to the traditional PID controller, the dynamic and static performance of the system is improved and theovershoot of the system is reduced, the response speed is faster. Because of the influenceof evenly divide of domain and rationality of expert experience, fuzzy PID controllerdidn’t reach the best control effect. Fuzzy PID controller based on improved geneticalgorithm optimization, can get the ideal control rules and reasonable fuzzy partitionthrough the strong global search ability of genetic algorithm, so the overshoot of systemis small and response speed is fast. The control quality of the controller is obviouslyimproved by applying genetic algorithm to the fuzzy PID controller. The simulationresults showed that the fuzzy PID controller optimized by the improved genetic algorithmhas good control effect.An intelligent greenhouse remote control system based on fuzzy control has beendesigned. The structure of this system is composed of four layers: a remote computer istaken as the client-side, a local computer is taken as the server-side, and a single chip ofStc15f2k60s2is adopted as the greenhouse controller, a data collection unit and actuators.Local computer greenhouse intelligent control software is composed of six modules ofdifferent function: human-computer interaction interface module is used to achieve systemlanding and password management; Data receiving display module is used for real-timenumerical and graphic display of environment parameters including temperature, humidity,illumination and CO2concentration of greenhouse, storage of data received fromgreenhouse controller, and over-limit alarm. Parameters setting module can be used to setenvironment parameters according to needs of different growth stage so as to providereference data intelligent control; Control strategy module is used for analyzing andprocessing data information received from greenhouse controller and provides intelligentautomatic control or manual control for the greenhouse; Status display module can real timedisplay running status of actuators; Communication module fulfills the setting ofcommunication protocol and receiving and sending of data.Greenhouse controller can real-time display temperature, humidity, illumination andCO2concentration and running state of actuators of greenhouse and control the actuators running state according to the command received from local computer; Field layer consistsof data collection system including temperature and humidity sensor、light sensor and manyactuators.And of control strategy, the control mode can be divided into two which are springsummer autumn mode and winter mode. In spring summer autumn mode, humidity isdivided into three levels of high, middle and low, under the three levels, the day (24h) isdivided into four which are morning from6to14, afternoon from14to19, nightfall from19to24and night time from0to6to realize fuzzy variable temperature control. In wintermode, the day (24h) is divided into two which are day and night to realize variabletemperature control.The communication between remote computer and local computer is implemented byprogramming of VC++6.0, input the web address of local computer in greenhouse remotecontrol software of remote computer, when network connection is successful, theenvironment parameters and actuators running state can be real-time displayed in theremote control software and the opening and closing of actuators in the greenhouse can bemanual controlled by remote computer.The experimental results shows that the system is user-friendly and easy operation, itcan achieve real-time display of environment parameters and actuators running state andintelligent control of the greenhouse environment according to the control strategy,environment parameters can be controlled in set range and it can create proper growthenvironment for cucumber. In addition, the system is easy to modify the control parameterssuch as temperature and humidity so as to adapt different needs of plants. It’s convenientfor technician or managers to monitor and control the greenhouse environment and runningstatus of actuators from remote computer in different province or city or even in differentcountry, so as to achieve the purpose of staff reduction and efficiency increases.