针对山地果园作业环境复杂,对运送装备的通过性要求高的特点,设计了一种轻简电动履带运输车,具有遥控和手动控制两种控制方式,远程遥控距离可达200m.实地样机试验结果表明:运输车的最大载荷为300kg,最大爬坡度为25°,最高车速为1.5m/s,具备原地差速转弯能力;其越障能力较强,对地形复杂、路况恶劣的山地果园环境适应性较好,能够满足山地果园的运输要求.

For the requirement in container nursery culture that growing media should be achieved the appropriate degree compaction, this paper presents an experiment on the compaction dynamics of air-dried soil under repetitive drop shocks, as a preliminary step toward the mechanization of this compaction method. The drop height used to adjust the shock intensity included 2 mm, 4 mm, 5 mm and 6 mm. And the overall packing density of soil in a vertically stratified cylinder vessel and the local packing density in each layer were taken as indicators of soil compaction states. The stretched exponential function derived from KWW law than the empirical inverse-logarithmic function has been found to be more suitable for expressing the temporal evolution of soil compaction, according to the results of curve-fitting to test values of the overall and local density. It is inherent in this experimental configuration that the drop shock intensity even at a constant drop height varies with drop times, owing to the interaction between the soil packing itself and drop shocks caused by the combination of the packing and the container. But the function t/τf(t,H) is manifested as a straight line on the drop times t with the line slope related to the drop height H, so the soil compaction dynamics caused by its drop shocks and that under the condition with actively controlled intensity actually share the common relaxation law. In addition, the soil’s one-dimensional distribution of local packing density showed a slight positive gradient as similar as monodisperse particles did.

主要分析了基于TOF测量技术的深度相机的深度误差产生的原理,针对ARGUS-A5型号深度相机产生的各类误差建立相对应的误差补偿模型,消去其误差影响.首先,利用黑白棋盘格标定法及Matlab摄像机标定工具箱标定了深度相机的内参矩阵以及畸变系数,消除了光心偏移误差、畸变误差;其次,基于针孔成像模型建立了平面误差补偿模型,消除了成像平面像素点的深度高估误差;最后,在不同深度下采集一个标准平面的数据,与真实深度数据进行线性拟合,建立深度信息误差查找表.结果表明,补偿后深度信息误差下降率为95.38％,最大误差率减少9.66％,补偿时间在20 ms内.

黄龙病是一种以柑橘木虱为传播媒介的毁灭性病害,其关键预防措施是在果园现场环境对柑橘木虱识别监测,辅助果农进行早期防治.该研究基于YOLOv4-Tiny模型提出一种适用于嵌入式系统的柑橘木虱识别模型.通过改进YOLOv4-Tiny模型的颈部网络,利用浅层网络的细节信息以提高模型识别柑橘木虱的平均精度;采用交叉小批量归一化(Cross mini-Batch Normalization,CmBN)方法代替批归一化(Batch Normalization,BN)方法,通过累计卷积层的输出,提升统计信息的准确度;针对柑橘木虱易被遮挡的问题,模型训练时使用Mosaic数据增强,提升模型对遮挡目标的识别能力.通过自行建立的柑橘木虱图像数据集完成模型的试验验证.结果表明,该模型的柑橘木虱平均识别精度为96.16％,在图形处理器(Graphics Processing Unit,GPU)上的推理速度为3.63 ms/帧,模型大小为24.5 MB,实现了果园环境下快速准确地识别柑橘木虱,可为黄龙病防治技术的进一步发展提供参考.

为避免山地果园单轨运输车在运行过程中碰撞到作业果农、牲畜、大型石块等障碍物,提高果园作业的安全性和稳定性,采用深度相机基于渡越时间法设计一套山地果园单轨运输车避障系统.该系统运行时由深度相机获取运输车通行通道障碍物信息,经过运行Linux系统的树莓派车载电脑进行数据处理,做出决策后下发标志位信号至运输车控制中枢Stm32微控制器,控制电机改变运动状态.试验结果表明:该系统对于障碍物识别率为100％,对于符合修剪要求的干扰型侧枝,其误触率在8％以下,避障最小制动距离为101 cm,系统最大延时0.475 s.

采用Mask R-CNN和YOLOv3算法对复杂背景场景下的柚子进行目标识别和分割,通过微调方法训练了2个实例分割模型,并应用于柚子相关目标的识别和分割.结果表明,YOLOv3模型的帧速率为18～20 FPS,Mask R-CNN模型的帧速率为0.5～2 FPS,YOLOv3模型的目标检出率比Mask R-CNN模型少30％以上,包围框定位精度比Mask R-CNN模型偏离10％以上.基于Mask R-CNN模型输出的Mask提出的外形估算方法,免标定像素尺寸,时间复杂度为T(n),便于轮廓对比.基于目标边框对柚子角度进行计算,角度动态范围为±5°.说明基于实例分割的柚子外形估算和品质评价方法,能适应复杂图像背景,具有较强的泛化能力.

Low-cost transporting vehicles are a crucial routine for orchards in the mountainous place. As the core component of the mountainous orchard carrier, the wire rope is easily damaged due to frequent handling of agricultural materials. The mechanical model of carrier wire rope is the prerequisite for studying its damage mechanism. This paper first analyzes the load-bearing characteristics of the wire rope of the carrier and then uses the theory of differential geometry and the elasticity of the wire rope to establish the mechanical model of the wire rope side strand strain ε0 and the axial load T of the wire rope end face in the erect state and the radial contact pressure Fa of the wire rope at the bending section and the mechanical model of the axial tension F and the pulley diameter D of the wire rope end face. On the basis of the mechanical model and the wire rope geometric solid model, the finite element stress analysis of the wire rope in the vertical state was carried out to verify the accuracy of the wire rope stress model. The results show that when the wire rope was in the vertical state, the wire-wire contact stress was linear directly proportional to the load on the end face of the wire rope; the wire-wire contact stress between the strands was about 12 times that within the strand; the average error between the simulated value and calculated value was about 13.6%, proving the correctness of the established wire mechanics model. When the rope and wheel were in contact, the contact pressure of the outer wire of the side strand was only related to the axial tension of the wire rope end face and the diameter of the pulley but not to the elasticity modulus of the pulley.

山地轨道运载机牵引系统主要包括驱动卷筒、钢丝绳及载物滑车,钢丝绳是其核心组成部分.目前还没有明确针对山地轨道运载机钢丝绳的空间数学模型,为了进一步研究钢丝绳力学模型及失效行为,需要推导空间几何数学模型与三维模型,从而避免大规模试验来探究钢丝绳的使用寿命及其损伤规律.首先,山地轨道运载机属于农业运载新式机械,作业环境复杂,因此本文对钢丝绳绳径进行了重新计算.然后利用微分几何学及空间坐标变换原理,推导了山地轨道运载机牵引钢丝绳在直立及弯曲状态的空间螺旋方程.最后,为更直观了解该类钢丝绳的结构,通过已建立钢丝绳空间数学模型,运用MATLAB参数化功能及Solidworks软件曲线、扫描和实体阵列等功能建立钢丝绳三维实体模型.结果表明,通过推导出的钢丝绳在直立及弯曲状态的空间螺旋方程,得出该类钢丝绳直线段和弯曲段的曲率与挠率呈明显的周期性变化规律,并在三维建模中得到钢丝绳股和丝参考点系列坐标.提出了适用于山地轨道运载机牵引钢丝绳的空间螺旋方程,为后续轨道运载机钢丝绳力学模型建立及损伤机理的研究奠定基础.

为实现苗圃田间果树钵苗的快速搬运,研制了一种适用于苗圃田间的自走式电动双轨运输机.针对运输机的应用环境、果树钵苗质量大小等需求,分析提出运输机应具备的装载量、电机功率、运输速度等设计参数;并根据技术参数要求,提出运输机的总体结构并对关键部件进行设计;最后,对运输机进行了实验室与田间试验.试验结果显示,运输机载重能力为750 kg,空载每百米能耗为9.16 W·h,满载每百米能耗为27.6 W·h,运行速度为0.564～0.718 m/s,运输机从起步到匀速行驶所用时间小于2.5 s,紧急制动距离小于0.05 m,振动加速度振幅总体小于0.4 g.以上结果表明,研制的运输机可以满足实现苗圃田间作业需求,可以有效提高作业效率、降低劳动强度.

针对钢丝绳牵引式双轨运输机的牵引钢丝绳在弯曲起伏轨道上作业时,易出现乱绳和挤绳所带来的安全性问题,本研究设计了一种无需钢丝绳的自走式电动双轨运输机,该运输机以三拓GW114165电动机为动力,2个12-LPA-24铅酸蓄电池作为能源,采用一主动多从动的后驱传动方式.通过电流测试试验、平地能耗试验和打滑性试验验证了该运输机的安全与稳定性,并结合三因素三水平正交试验法考察驱动轮材料、轨道坡度和装载质量对运输机运行速度的影响.结果显示:在试验条件下,采用一主动多从动的后驱传动方式爬坡性能良好,运行比较平稳,但尽量不要在满载的爬坡状态下在陡坡处停机,如需停机,可人为辅助启动,运输机运行速度为0.241～0.700 m/s,平地运行航程为3560～6489.1 m.驱动轮材料、轨道坡度和装载质量等因素对运输机运行速度的影响依次是轨道坡度>驱动轮材料>装载质量,其中坡度对运行速度的Sig值为0.049,小于0.05,影响最为显著.

In order to reduce the vibration of mountain self-propelled electric monorail transporters (MSEMT) caused by the impact of the meshing of roller gear with toothed rail (MRGTR), and to improve the stability and safety of monorail transporters, this paper theoretically analyzed the MRGTR mechanism of toothed monorail transporters as well as established the MSEMT displacement model and its instantaneous velocity model. The vibration signals of MSEMT with four different parameters of toothed rail were collected by the acceleration sensor and signal acquisition system. The signals were analyzed by the Hilbert envelope demodulation method to investigate the influence of toothed rail parameters on meshing impact vibration. Moreover, taking the vibration acceleration amplitude of MSEMT and the vibration attenuation time of meshing impact as evaluation indexes, a test based on the three-factor and two-level orthogonal test was engaged with factors of toothed rail pressure angle, the ratio of L-the chord length of two adjacent roller centers of a roller gear-and rack pitch p (wheel-tooth ratio) and the load mass of the MSEMT. It showed that the impact of MRGTR was the main excitation source of the vibration of MSEMT. The pressure angle and wheel-tooth ratio both have a significant impact on the smooth operation of MSEMT, the latter to a greater extent. So did the interaction between wheel-tooth ratio and load mass. The amplitude of the characteristic frequency of the MSEMT decreased with the growth of the pressure angle. When the wheel-tooth ratio was cosα, the number of the characteristic frequency was less than that when it was 1, and the amplitude became smaller too. When the pressure angle was 15, the amplitude of vibration acceleration characteristic frequency decreased as a consequence of load mass increasing. At the pressure angle of 25, the amplitude of characteristic frequency decreased with the increase of load mass if the wheel-tooth ratio was 1, and the opposite result occurs in the case when the wheel-tooth ratio was cosα. This paper provides a theoretical basis and reference for improving the impact vibration of MRGTR and optimizing the design of the toothed rail.

为了提高液肥深施效率,设计了一种基于ZigBee的液肥变量深施系统.该系统采用远程电脑终端与STM32F103RET6控制器同步结合实现液肥输出监测与控制:监控液肥水位值的同时利用流量传感器采集当前流量值,并通过ZigBee无线通信协议传输数据;根据流量预设值,利用增量式PID算法动态调整变频器频率,最终使试验系统能够精确控制液肥流量输出.在试验系统的基础上,通过液肥深施试验以探讨施肥深度、变频器频率、注肥压力、系统用泵的回水开度等参数对流量精确控制的影响,并利用试验数据建立精准控制流量的数学模型.果园试验结果表明,液肥变量深施系统整机施肥精度最高可达99.52％,单次施肥的液肥损耗量最大值为0.22 L/min;在改变施肥深度的情况下,系统液肥输出流量的最大差值为0.15 L/min,变频器频率的最大差值为0.79 Hz.在改变回水开度的情况下,确定了试验中系统的最佳工作参数,即回水开度在40％时,系统工作最为稳定,流量输出误差小,液肥损耗量少.

在阐述山地果园牵引式双轨运输机用钢丝绳动力学与接触力学模型的基础上,搭建了基于PLC模拟钢丝绳实际运行的绕卷试验平台,设计了试验平台的变频凋速系统与控制系统,并安装和调试了张紧力自动调节装置;搭建了一套基于漏磁法的钢丝绳断丝与磨损检测平台,进行了钢丝绳探伤仪断丝与磨损可靠性试验.在拉力传感器标定与调节装置性能测试试验中,推拉力计的拉力输出值与注水质量呈线性关系,且试验张紧力偏差浮动范围为-130～85 N,结果满足试验要求.钢丝绳断丝与磨损检测试验结果表明,在模拟断丝数依次为10、20、30根的情况下,试验绳10次重复试验检测的断丝数与实际值相同,说明检测平台可精确检测钢丝绳断丝数及断丝位置;但是,通过探伤仪检测的模拟磨损情况与实际值偏差较大,无法对钢丝绳磨损进行准确的检测.

The regularity of wire rope breakage of new-type rail conveyors used in orchards is not clear yet. The breakage may be mainly associated with the diameter and material of pulleys, wire rope tension, and linear speed, as well as exposure to acid rain and sandy soil. This paper took wire rope structure and operating parameters as the research object, designed and built a simulation conveyor wire rope winding test platform based on programmable logic controller (PLC), and verified the feasibility of the system to automatically control wire rope tension, and then conducted the wire rope winding test. According to the tests, a wire rope will have earlier wire breakage and faster wear if it works at a higher speed or in greater tension-a wire rope reached the scrapping criterion after 2,000 cycles of working at the speed of 29.35 m/s or at the tension of 6,500 N. Sandy soil and acid rain are also great contributors to wire breakage, and finer sandy soil or greater acidity of acid will cause more severe wire breakage-a wire rope reached the scrapping criterion after 3,300 cycles of work if exposed to acid rain with pH value of 2.0. Pulley diameter also counts: the smaller the pulley diameter is, the less wear the pulley will cause; and pulley material also plays a part-Q235 steel pulley may cause greater wear than a nylon pulley. Wear and plastic deformation of outer wires lead to surface material loss of a wire rope, thereby resulting in crack or even fracture of single wires, greater tension of other unbroken wires, and accelerated wear of the whole wire rope to the scrap criterion. The study aims to provide a reference for optimizing the safety performance of conveyors in orchards, as well as for maintenance and care of wire ropes in other applications.

针对山地果园单轨运输机作业环境受限、定位精度较低等问题,该研究基于高频RFID(Radio Frequency Identification)混合测速定位方法,设计了一套果园单轨运输机在轨状态精准感知系统.感知系统以STM32F103RCT6芯片为主控单元,利用双RFID阅读器读取基准定位标签组的时间差,使用混合测速定位方法,实时计算运输机的作业状态信息;设计了移动端监测软件,通过LoRa通信模块远程获取运输机实时作业状态信息.试验结果表明,运输机在平地路况中运行稳定,感知系统计算的全程平均行驶速度为0.49 m/s,依据秒表记录计算的全程平均行驶速度为0.48 m/s,二者速度相差2％;基准定位标签组间距为3.42 m时,运输机全程平均定位误差为6.18±0.60 cm;基准定位标签组间距为6.84 m时,运输机全程平均定位误差为6.46±1.14 cm.该研究验证了基于高频RFID精准感知单轨运输机在轨状态的可行性,提升了运输机作业安全性和智能性,可为实现果园生产精准作业提供可靠数据支持.

[目的]简化果园网络部署,延伸信号覆盖范围,提供精细、实时的灌溉监控,并提高其对传统设备的兼容性.[方法]通过窄带物联网(NB-IoT)和LoRa混合组网实现远程数据传输、延伸基站信号覆盖范围.采用终端电学参数检测电路及标定功率,结合异常检测算法,精准监测设备运行状态,并将异常状态即时上传,降低数据上传频率.同时在保证处理能力的前提下降低处理器主频,从而延长待机时长.[结果]果园现场监测系统实现了150 ms内上报异常状态,并将上报次数限制为每年2万次.校正检测功率后,功率的线性回归预测决定系数(R2)为0.9998.通过宏生成JSON数据,生成时长为cJSON方法的10％,进一步降低MCU计算需求.在满足计算和控制需求的前提下,2 MHz的微处理器主频和200 mA·H锂电池可以满足果园灌溉监控系统计算和持续工作的最低要求,采用低功耗微处理器可以进一步延长工作时间.[结论]监控系统延伸了NB-IoT网络的覆盖范围,可实现精准、低成本和实时的远程监控.

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K LWA,K LWA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％.

我国南方丘陵山地水果生产中,农资物料和果品的运输主要依靠人力,生产效率低、劳动强度大,因此,生产过程中机械化运输的作用日趋体现.本文主要介绍由国家柑橘产业技术体系机械化研究室研发的山地果园自走式电动单轨运输装备的关键技术内容和应用推广经验.针对如何提高我国山地果园运输机械化水平,提出了进一步提升果园建设的规范程度、提升装备技术的标准化程度和提升果农对新型农业机械了解程度的3项建议.

针对目前山地林果茶园挖穴作业人工劳动强度大和作业效率低的问题,设计了一种具有行驶动力的山地林果茶园电动自走式挖穴机.该挖穴机能自动完成钻头进给行程与复位行程.田间试验结果表明,该挖穴机单次作业平均挖穴时间为50.7 s,单次有效挖穴作业能耗为6.38 W·h,施肥穴平均深度为392.5 mm,施肥穴平均直径为303 mm,行走速度为1.237 m/s,能够顺利通过15°斜坡.挖穴作业过程中钻头的进给与回程运动均无需人工操作,可提高工作效率,降低劳动强度,并保证挖穴操作中的安全性.

通过整合华南农业大学和广东省农业科学院果树研究所相关学科力量,柑橘农科教合作人才培养实践教学基地已经建成.基地针对本科生和研究生的培养设计三种形式的实践教学,组建一支结构合理的师资队伍,建设完善的实习课程体系,同时通过举办讲座和示范会,提高基地所在地农技人员的技术水平.