Research On The Control Method Of Temperature Environment Variable In Modern LED Plant Factory

Plant factory is a high precision facilities to realize the control of the internal environment,the interior crops can achieve continuous and efficient production.In the process of plant growth,Photon flux density?air temperature and humidity?CO2 concentration?nutrient solution temperature and plant wind speed can be automatic controlled by the PLC?MCU or IPC.With the development of society,modern plant factory has earned more and more attention.Techniques used in the plant factory involve agriculture ? automation and computer software.It can decrease the affections caused by the external environment to plant growth.Plant factory can be built in the remote areas with bad weather,also inside the city building.Plant factory reduce the demand of agricultural labor,improve the level of agricultural industrialization,and promote the development of electronic information and equipment manufacturing industry.This research focuses on the establishment of the general environment and the optimization of temperature control in the modern LED plant factory:1.Design the hardware and software environment for Plant factory,Plant factory sensors can measure air temperature and humidity?CO2 concentration? Photon flux density?nutrient solution temperature and wind speed,and the control core is STM32 with Ethernet port.The actuators are the air compressor?heating rods?LED lamp board?nutrient solution heating cooler device,fan,CO2 generator and humidity generator.The main controller control the brightness of the LED lamp through by controlling the LED driver board,and the communication verification used by the CRC16.The main controller communicates with Devin touch screen through the serial port RS232,Devin touch screen can realize monitoring the effects on plant.2.The system uses the JAVA host computer to communicate with controller,the host computer can monitor a number of plant growth cabinets.The PC and the main controller communicate by the via Ethernet port.This system compares the difference between OSI model and TCP/IP model and design the log in?selecting and monitoring interface.3.The temperature rise is curve fitted by CFtool,and the mathematical model of the temperature rise curve is obtained by using the least square method.In order to measure the accuracy of the temperature sensor,temperature measurement added in the rolling filter algorithm.And the bit control embedded into the controller,can realize the control of the direction of temperature,reducing the temperature oscillation in a temperature node action.4.Plant factory temperature is a complex control system with multi variable and nonlinear.Thissystem using the empirical formula of the temperature system modeling,the temperature control system is simulated by PID and fuzzy PID algorithm.And the advantages of fuzzy PID control are analyzed by simulation model,the PID algorithm and fuzzy PID algorithm are embedded into the controller.When using fuzzy PID control,the average value of temperature is closer to the temperature setting value by measuring the temperature data.