苗期玉米间歇变量施药控制系统设计与试验

Design and Experiment of Batch Application Control System for Maize Seedling

针对苗期玉米连续式施药易造成农药浪费问题,研制了喷杆式喷雾机间歇施药控制系统。基于施药机整机及液压系统构成,搭建了以PLC控制器为核心的硬件控制系统,通过超声传感器实时检测目标苗株,建立了作物高度(即物距)与其受药时长、单位时间喷药量的关系模型。为稳定系统压力、降低管路扰动影响,开发了基于PID算法的压力闭环控制策略,通过MatLab仿真确定了控制参数K_(p)、K_(i)、K_(d)分别为0.01、50、0.05。台架试验结果表明:系统的变量施药控制精度相对误差在±5.57%以内,压力闭环控制精度相对误差在±4.71%以内,间歇变量施药控制系统具有较好的流量控制精度及压力稳定性,满足作业要求。

Aiming at the problem of pesticide waste caused by continuous spraying in maize seedling stage, a control system of intermittent and variable spraying for rod sprayer was developed. Taking the PLC controller as core, the hardware control system based on the whole sprayer machine was developed. After the target maize seeding detected by ultrasonic sensor, the relationship model of plant height(object distance) and spraying time-period or application rate per unit time. To maintain system pressure and deduce disturbance of pipeline, the closed-loop control strategy based on PID algorithm was developed, and the parameters of K_(p),K_(i)和K_(d) were 0.01, 50, 0.05, separately. The experiment result showed that: the relative error of variable spraying control system was less than ±5.57%, and the relative error of closed loop control system for pressure was less than ±4.71%. The control system for intermittent and variable spraying had a good performance in control precision of flow rate and good pressure stability to meet the work requirement.