滴灌棉田施肥系统水肥EC值控制策略研究

Study on Control Strategy of Water and Fertilizer EC Value in Drip Irrigation Cotton Field Fertilization System

在现今新疆兵团农业生产中,已基本实现了滴灌系统的推广使用,但在滴灌系统中广泛使用的施肥罐,常常会出现肥料溶液浓度难以把握、时间不易控制的问题,国外先进的灌溉施肥设备在国内应用的生产效果并不理想,不适应我国的气候条件和种植生产环境,因此国内急需一种精确的水肥一体化自动控制系统,来解决这一弊端。针对这一现象,设计了一套基于模糊-PI复合控制的水肥EC值控制系统,结合模糊控制鲁棒性好和PI控制精度高的特点,通过控制母液罐电磁阀开启时长来调节水肥的EC值。用Matlab软件对模糊-PI复合控制下的系统进行了仿真,并依次对比了PI控制、模糊控制下的仿真,结果表明:相比于PI控制、模糊控制分别单独控制时,设计的模糊-PI复合控制下的系统的超调量和调节时间均明显缩短,动态性能更佳,可以用于滴灌棉田施肥系统的水肥EC值调控。

In the agricultural production of Xinjiang Corps,the popularization and use of drip irrigation system has been basically realized.However,the widely used fertilizer tank in drip irrigation system often has the problems of difficult to control the concentration of fertilizer solution and difficult control of time.The production effect of advanced foreign irrigation and fertilization equipment in the domestic application is not ideal and cannot adapt to domestic climate conditions and planting production environment.Therefore,an accurate integrated water and fertilizer automatic control system is urgently needed in China to solve this drawback.In view of this phenomenon,this paper designed a set of water and fertilizer EC value control system based on fuzzy-PI composite control.Combined with the characteristics of good robustness of fuzzy control and high precision of PI control,the EC value of water and fertilizer was adjusted by controlling the opening time of solenoid valve in mother liquid tank.The system under the fuzzy-PI compound control was simulated with Matlab software,and in turn,compared with the simulation results of the system under PI control and fuzzy control.The results show that compared with PI control and fuzzy control separately,the system designed in this paper under the fuzzy-PI composite control can significantly shorten the overshoot and adjustment time,and has better dynamic performance.It can be used to control the EC value of water and fertilizer in drip irrigation system of cotton field.