摘要
在液态肥寻种对靶点施系统中,液态肥需满足在高频间歇喷施时压力波动较小且在间歇喷射频率发生变化时仍能保证压力稳定的要求,为此设计了基于PID算法的高频间歇供肥系统。设计了供肥系统硬件电路和软件程序,对管路压力进行采集与控制,并设计了可方便设置作业参数和显示实时作业状况的人机交互界面。采用临界比例度法对PID算法进行参数整定,经实际试验调整后确定PID算法的比例系数、积分系数和微分系数分别为4、0.079和0.012,对采用和不采用PID算法的供肥系统压力变化情况进行了对比试验,结果表明,采用PID算法的供肥系统压力更加稳定。为评价基于PID算法的供肥系统在不同作业速度和压力设定值下的压力稳定性能,选取管路压力的最大误差、平均误差和标准差为试验指标,进行了台架试验。结果表明,供肥系统压力的最大误差、平均误差和标准差分别不大于6.49%、1.54%和0.40 MPa,满足液态肥寻种对靶点施系统对于管路压力稳定性的要求。
Liquid fertilizer has the advantages of easy absorption,high efficiency and low environmental pollution compared with granular fertilizer.To achieve precise application of liquid fertilizer,a detecting seeds and target-spot application system of liquid fertilizer was proposed.The system needed liquid fertilizer to meet the requirements of small pressure fluctuations during high-frequency intermittent spraying,and ensure pressure stability when the intermittent spraying frequency was changed.Thus,a high-frequency intermittent fertilizer supply system was designed based on PID algorithm.Through the study of the hardware circuit and software program of the fertilizer supply system,the collection and control of the pressure for the fertilizer supply system was realized.And the interactive interface was designed to facilitate the setting of operating parameters and the display of real-time operating conditions.In order to get the best parameters of the PID algorithm,the critical proportion method for parameters tuning was used.After actual experimental adjustment,the proportional,integral and differential coefficients of the PID algorithm were determined to be 4,0.079 and 0.012.A comparative test was implemented to compare the pressure change of the fertilizer supply system with and without the PID algorithm.The results showed that the pressure of the fertilizer supply system with the PID algorithm was more stable.To evaluate the stability of the fertilizer supply system based on PID algorithm at the operating speeds of 3 km/h,4 km/h and 5 km/h and the setting pressure of 0.10 MPa,0.15 MPa,0.20 MPa,0.25 MPa and 0.30 MPa,a bench test was carried out.The test indicators were maximum deviation,average deviation and standard deviation of the pressure for the fertilizer supply system pressure.The test results indicated that the maximum deviation,average deviation and standard deviation were not more than 6.49%,1.54%and 0.40 MPa,which satisfied the requirements of detecting seeds and target-spot application system of liquid
作者
于畅畅
李洪文
何进
陈桂斌
卢彩云
王庆杰
YU Changchang;LI Hongwen;HE Jin;CHEN Guibin;LU Caiyun;WANG Qingjie(College of Engineering,China Agricultural University,Beijing 100083,China;Beijing Key Laboratory of Design and Optimization in Modern Agricultural Equipment,Beijing 100083,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2020年第11期45-53,63,共10页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家重点研发计划项目(2016YFD0200600)。
关键词
液态肥
供肥系统
PID算法
参数整定
liquid fertilizer
fertilizer supply system
PID algorithm
parameter tuning
