摘要
变量喷雾技术是提高喷雾效果、降低农药使用率的有效手段,而准确的树冠特征参数检测及施药量模型是其关键。为克服果园变量喷雾中果树特征参数检测效率低和对环境要求高的缺陷,该文通过LiDAR(light detection and ranging)检测技术获取表征树冠特征参数的叶墙面积LWA(leaf wall area),并利用图像处理技术计算树冠参数参考值。为了表征树叶密度和LWA对变量喷雾的共同影响效果,研究基于LWA的决策系数KLWA,KLWA由反映果树冠层分区内点云在水平方向平均深度下的分布密度K1和分区内点云分布高度极差占分区高度的比值K2加权决定。通过计算垂直方向各分区内决策系数KLWA,并代入流量函数可得出基于KLWA的施药量计算模型,进一步计算电磁阀PWM占空比并调节水泵和电磁阀的工作状态,使喷头的流量对应冠层各区得到动态调整,实现基于LWA的变量喷雾。利用自制的室外变量喷雾验证装置,进行了多喷头变量喷雾试验,试验结果表明,果树的药液附着率均接近100%,说明基于LWA的变量喷雾模型可实现有效喷雾,与连续喷雾相对比,基于LWA的变量喷雾施药量模型的省药率为68.34%,与纯对靶定量喷雾比,基于LWA的变量喷雾施药量模型的省药率为32.77%。
Variable spray technology is an effective means to improve the spray effect and save pesticide.The accurate canopy characteristic parameter detection and application rate model are the decisive stages for precise variable sprays.In order to solve the problems of low efficiency and high environmental requirements in the orchard variable spray system,in this article,LiDAR(light detection and ranging)detection technology was used to obtain the LWA(leaf wall area)which represented the characteristic parameters of tree canopy,and image processing technology was used to calculate the reference value of canopy parameters.The leaf wall area was drawn by two orthogonal images.According to the scale in the image,some coordinate points on the curve were obtained by using MATLAB,and the leaf wall area of the simulation tree was obtained by integral solution.The decision coefficient KLWA based on LWA was studied,so that the effects of foliage density and LWA on the variable spray were characterized.KLWA was determined by the weighted sums of K1 and K2,where K1 reflected the distribution density of point cloud in the tree canopy area under the average depth in the horizontal direction,K2 represented the ratio of the extreme difference in the height of the point cloud distribution to the height of the subarea within the canopy subarea.By calculating the decision coefficient KLWA in each vertical direction,and by substituting the flow function,the calculation model of pesticide dosage based on KLWA can be obtained.Using the control variable method,the multi nozzle flow model is studied.With the PID controller to rapidly stabilize the pressure and the fixed PWM frequency of solenoid valves,the multi-nozzle flow model experiment has been conducted.By calculating the duty cycle of the solenoid valve PWM and adjusting the working state of the pump and solenoid valve,so that the flow rate of the sprinkler can be adjusted dynamically to the various parts of the canopy,and variable spray based on LWA can be realized.On this foundation,A variable spray verification device was designed,which consisting of LiDAR,10 m track,4 nozzles,3 artificial trees with a crown of 1.47 m,1.70 m,1.60 m were built outdoors and a multi-nozzle variable spray test was carried out.To explore the effect of calculation model of pesticide dosage based on LWA,2 other conventional orchard spray methods were selected as reference sprayers for comparison in this article.The fist reference type was continuous spray,the second reference sprayer is pure quantitative spray to target.The test results showed that,the adhesion rate of the liquid spray is close 100%,indicating that the variable spray model based on LWA can achieve effective spraying.The pesticide saving rate of the variable spray application rate model based on KLWA was 68.34%compared with continuous spray.Compared with pure quantitative spray to target,the pesticide saving rate of the variable spray application rate model based on KLWA was 32.77%,and the drug saving effect was remarkable.The research method provides the basis for theoretical research and optimized design of plant protection equipment,and also references for further improving the spray effect and the pesticide utilization rate by variable spray.
作者
薛秀云
许旭锋
李震
洪添胜
谢家兴
陈建泽
宋淑然
Xue Xiuyun;Xu Xufeng;Li Zhen;Hong Tiansheng;Xie Jiaxing;Chen Jianze;Song Shuran(College of Electronic Engineering,South China Agricultural University,Guangzhou 510642,China;Division of Citrus Machinery,China Agriculture Research System,Guangzhou 510642,China;Guangdong Engineering Technology Research Center for Mountainous Orchard Machinery,Guangzhou 510642,China;College of Engineering,South China Agricultural University,Guangzhou 510642,China;Guangdong Engineering Research Center for Monitoring Agricultural Information,Guangzhou 510642,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2020年第2期16-22,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金(31671591,31971797)
广东省科技计划项目(2017A020208049)
广东省普通高校特色创新项目(2018KTSCX020)
现代农业产业技术体系建设专项(CARS-27)
2018年省级农业科技创新及推广项目(2018LM2163)
广东省现代农业产业技术体系创新团队建设专项资金(2019KJ108)
2019年广东省教育厅特色创新类项目“基于大数据和人工智能的空地一体化荔枝龙眼生长精准管控关键技术研究与应用示范”。
作者简介
薛秀云,高级实验师。从事施肥技术、喷雾技术研究Email:xuexiuyun@scau.edu.cn;通信作者:宋淑然,博士,教授。主要从事喷雾技术及测控技术研究。Email:songshuran@scau.edu.cn。
