轮灌条件下灌溉施肥系统混肥过程变论域模糊控制  

Variable Universe Fuzzy Control of Water-fertilizer Mixing Process in Fertigation System under Rotational Irrigation Situation

作　　者：牛寅[1] 张侃谕[1,2] 

机构地区：[1]上海大学机电工程与自动化学院,上海200072 [2]上海大学电机与控制工程研究所,上海200072

出　　处：《农业机械学报》2016年第3期45-52,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：上海市科委重点科技攻关项目(10DZ2212300)

摘　　要：灌溉施肥系统的混肥过程在轮灌条件下表现出非线性、时滞性、时变性和不确定性的特点。为解决该系统的控制问题,提出了一种变论域的模糊PI控制策略(VFPI),算法采用一组比例指数函数作为伸缩因子对模糊控制器的论域进行在线调整,同时引入了一个协模糊控制器,通过测量系统流量的变化在线调节控制器积分系数的基准值。为验证控制算法的有效性,搭建了灌溉施肥控制系统的试验平台,分别设计了4组不同配方内容和3组不同轮灌条件的模拟试验,采用本文提出的VFPI控制算法和常规PI控制算法进行了对比试验。试验结果表明,所提出的VFPI控制策略能够更好地适应配方内容变化以及轮灌条件变化对混肥过程造成的影响;相比于常规PI控制,VFPI控制的调节时间更短、超调量更小、动态过程更平稳。The water-fertilizer mixing process with an open-tank in the fertigation system was analyzed by a simplified dynamic mixing process in this paper. Then a variable universe fuzzy-PI control strategy was proposed which aimed at the characteristics of nonlinearity,pure hysteresis,time degeneration and uncertainty in the control system. A set of stretching factors with proportional exponential function was used to modify the universe of the fuzzy controller on line for improving its adjustability. Considering the influence of varied rotational irrigation schedule,a co-fuzzy controller with one-dimensional was proposed to regulate the reference value of integral coefficient of PI controller,through monitoring the system flow change on line. And the correction value of control parameters of PI controller were regulated by the variable universe fuzzy controller. In order to verify the validity and advantage of proposed control algorithm（ VFPI）,four experiments with different recipes and three experiments with different rotational irrigation situations that compared to the traditional PI controller were carried out,while the testing platform of fertigation control system was established. The contrast testing results demonstrate that the proposed VFPI control strategy has better adjustability than the traditional PI control method. When the recipe contents or rotational irrigation situations varied,the VFPI controller has smaller overshoot,better dynamic quality and reliability than the traditional PI controller.

关 键 词：轮灌 灌溉施肥系统 变论域 模糊控制 

分 类 号：S24[农业科学—农业电气化与自动化] TP29[农业科学—农业工程]