Design Of The Control System For Micro Plant Factory Based On Embedded Platform

The micro plant factory is the large-scale plant factory in miniature, which integrates all the technology used in the large-scale plant factories. Through the intelligent control system, it can provide the planted vegetables with comfortable environment and reasonable proportion of nutrient solution. Nowadays, the micro plant factory has been put into use in some developed countries like Netherlands, Japan and America who have the most advanced technology in the development of plant factory. However, the micro plant factory is still a new thing in the field of domestic protected agriculture. At present stage, PLC is widely used as the core controller combined with the PID algorithm in the micro plant factory control system, which leads to high cost and low accuracy due to the characteristics of strong coupling and long time delay of inner environment, and the results are generally not desirable.Developing an efficient and reasonable control system is always the pivotal problem in the research of the micro plant factory. Through the analysis of numerous control systems and the needs of the micro plant factory, this paper puts forward a new control system based on embedded platform. High performance STM32F103processor is used as the main controller in this system, and it can achieve better stability and reliability through the combination with embedded real time operating system μC/OS-Ⅱ. As for the hardware of the system, the circuit of controller has been designed including STM32core circuit, sensor data acquisition circuit, data storage circuit, LCD display and touch control circuit, and actuator control circuit. As for the software, embedded real time operating system μC/OS-Ⅱ has been transplanted, and the application software is programmed based on it. The development of man-machine interface is conducted through the transplant of μCGUI software package, and the SD card is applied to store the collected environmental factor information. Also, the modification of environmental parameters and query of historical data can be realized by the use of touch screen. Temperature and humidity, which play a crucial role in the process of plant growth, are selected as the research topics after a comprehensive analysis of the characteristics of environmental factors in the micro plant factory. Considering the problems exiting in the process of temperature and humidity control, a fuzzy control algorithm is presented. First, the fuzzy decoupling algorithm is used to eliminate the coupling effect between temperature control loop and humidity control loop, and then the fuzzy control algorithm is employed to control temperature and humidity respectively. Simulation and experiments have shown that the algorithm designed in this paper is reasonable and effective, and it can reach the expected target.The intelligent control system for micro plant factory based on embedded platform presented in this article has friendly man-machine interface. It not only has high stability and low cost, but also can expand the system according to the demand. It provides an option for the upgrading of exiting micro plant factory control system.