Design and experiment of variable liquid fertilizer applicator for deep-fertilization based on ZigBee technology
XUE Xiuyun1,2,3,4, ZHANG Bin1, ZHANG Zelong1, LIN Dongting1, SONG Shuran1,2,3,4*, LI Zhen1,2,3, HONG Tiansheng2,3,5
1. College of Electronic Engineering, South China Agricultural University, Guangzhou, Guangdong 510642, China; 2. Division of Citrus Machinery, China Agriculture Research System, Guangzhou, Guangdong 510642, China; 3. Guangdong Engineering Technology Research Center for Mountainous Orchard Machinery, Guangzhou, Guangdong 510642, China; 4. Innovation Team of Guangdong Agriculture Research System, Guangzhou, Guangdong 510642, China; 5. College of Engineering, South China Agricultural University, Guangzhou, Guangdong 510642, China
Abstract：To improve the efficiency of liquid fertilizer application, a variable liquid fertilizer applicator for deep-fertilization based on ZigBee technology is elaborated. A host computer with remote control software and a STM32F103RET6 microcontroller were combined to measure and control the li-quid fertilizer output: through the ZigBee wireless communication network, this system realized the collection of liquid flow information in real time using flow meter while monitoring the liquid level; and an incremental PID control algorithm was used to dynamically adjust the converter frequency for reaching the set liquid fertilizer flow accurately. In the meanwhile, the performance experiment in the field analyzed and compared how parameters like the fertilizer application depth, the converter frequency, the fertilization pressure and the opening degree of back-water valve influenced the accuracy and the stabi-lity of the liquid variable deep-fertilization control. On the basis of the test data, a precise flow control mathematical model is also established. As the result, the orchard experiments indicated: the applicator accuracy is able to reach 99.52% and the maximum liquid fertilizer consumption in each fertilization process is 0.22 L〓 /min; with the fertilizer application depth changing, the maximum flow output difference is 0.15 L〓 /min and the converter frequency difference is 0.79 Hz. When adjusting the opening degree of back-water valve to confirm the optimum working parameters, which means the valve opening degree is 40%, the system works the most stably while owns the minor flow output difference and the low liquid fertilizer consumption.
