Abstract:For the precise control problems of water and fertilizer solution concentration in the process of agricultural irrigation, the precise irrigation control system was developed based on PID control technology, the application of conductivity EC value and pH value control technology. We performed open-loop step response experiments and relay oscillation adjust experiments. The results showed that the system is nonlinear, inertial, and hysteretic. We also performed theoretical and experimental study on digital PID control for EC control. The results indicated that the PID controller has the advantage of high control accuracy, and some time has the disadvantage of performing badly when the fertilizer solubility changed considerably. Adopting open-loop step response theory, PID control and fuzzy control, we designed the intelligent PID controller. The results showed that the controller is auto-tuning of PID parameters, the settling time is 3 minutes, accuracy is within ±0.15 mS/cm, and overshoot less than 15%. With the combination of open-loop step control and PID control, we designed an alternative PID controller for pH, and experiments proved that it has some fine performance as mentioned above.
张育斌,, 魏正英, 朱新国, 胡杨, 李林章. 精量水肥灌溉系统控制策略及验证[J]. 排灌机械工程学报, 2017, 35(12): 1088-1095.
ZHANG Yubin,, WEI Zhengying, ZHU Xinguo, HU Yang, LI Linzhang. Control strategy for precision water-fertilizer irrigation system and its verification. Journal of Drainage and Irrigation Machinery Engin, 2017, 35(12): 1088-1095.
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