水肥一体化施肥机EC和pH改进自抗扰解耦控制  

Improved auto-disturbance-rejection decoupling control for EC and pH of water and fertilizer integrated fertilizer applicator

作　　者：李颀[1] 马琳[1] 王康 Li Qi;Ma Lin;Wang Kang(School of Electrical and Control Engineering,Shaanxi University of Science and Technology,Xi'an,710021,China)

机构地区：[1]陕西科技大学电气与控制工程学院,西安市710021

出　　处：《中国农机化学报》2020年第2期161-170,共10页Journal of Chinese Agricultural Mechanization

基　　金：陕西省农业科技创新工程(201806117YF05NC13)。

摘　　要：针对水肥一体化施肥机控制系统在交叉耦合、内外不确定条件下难以通过建立精确数学模型进行跟踪控制的问题,提出一种EC和pH改进自抗扰解耦控制策略。利用六次多项式曲线拟合对系统阶跃响应数据进行滤波处理,由面积法构建系统简化数学模型。选择静态解耦法实现系统解耦,对分解后的两个子系统分别设计自抗扰控制器并进行改进,给非线性状态误差反馈率添加类积分项,并引入模糊控制理论实现其参数在线自整定。仿真结果表明,系统EC和pH的调节时间分别为44 s和39 s,超调量分别为5.5%和0.3%,输出绝对误差分别小于0.1 mS/cm和0.2,该控制器能够实现系统高精度独立调节,相比于线性自抗扰和PID控制器,响应速度更快,抗干扰能力和鲁棒性更强。试验结果表明,该控制器调节误差与仿真结果吻合,并且能够使系统用水量、用肥量、用工量分别降低33.13%、35.75%、35.01%,作物产量提升15.16%,节水、节肥、节工和增产效果显著,具有很高的可行性。In order to solve the problem that the control system of water fertilizer integrated fertilizer applicator is difficult to track and control by establishing an accurate mathematical model under the condition of cross coupling and internal and external uncertainty, an improved auto disturbance rejection decoupling control strategy of EC and pH was proposed. The sixth order polynomial curve fitting was used to filter the step response data of the system, and the simplified mathematical model of the system was constructed by the area method. The static decoupling method was selected to realize the system decoupling, and the ADRC was designed and improved for the two subsystems after the decomposition. The class integral term was added to the feedback rate of the nonlinear state error, and the fuzzy control theory was introduced to realize the on-line self-tuning of its parameters. The simulation results showed that the regulation time of EC and pH were 44 s and 39 s respectively, the overshoot of EC and pH were 5.5% and 0.3% respectively, and the absolute errors of output were less than 0.1 ms/cm and 0.2 respectively. The controller can achieve independent regulation with high precision. Compared with the linear auto disturbance rejection and PID controller, it has faster response speed, stronger anti-interference ability and robustness. The experimental results showed that the adjustment error of the controller was consistent with the simulation results, and the water consumption, fertilizer consumption and labor consumption of the system can be reduced by 33.13%, 35.75% and 35.01% respectively, and the crop output can be increased by 15.16%. It is significant for the effect of water-saving, fertilizer saving, labor saving and production increase, which has high feasibility.

关 键 词：水肥一体化施肥机 静态解耦 自抗扰控制 鲁棒性 

分 类 号：S224.2[农业科学—农业机械化工程]