农机直线行走作业DGPS导航算法研究

对于大中型宽幅农业机组在大面积的田间行走作业中利用DGPS进行导航具有很多优点。本文对农机直线行走作业DGPS导航涉及的投影转换、导航AB线、行驶方向角、机组在导航AB线的左右位置、机组当前导航线与导航AB线之间的距离、偏航距离及左右确定等问题进行了分析并给出了算法。通过编程测试表明,本文涉及的算法可行,可用于农机直线行走作业DGPS导航中。     

基于GPS和GIS的农机作业导航系统

基于GPS和GIS的农机作业导航系统可以提高作业效率和作业质量,降低运行成本,减轻驾驶员的工作难度。介绍了系统软、硬件结构,系统实现了对农业机械提供道路行走导航和机组在田间作业中利用光耙进行直线导航的功能,并具有行走轨迹实时记录、作业面积计算统计、作业回放等功能,便于工作和信息化管理。     

基于GPS和GIS的农机田间作业回放研究

本文利用黑龙江垦区引进的精准农业装备采集的机组田间作业信息，生成了农业机械田间作业记录，进行了基于GPS和GIS的农业作业机组田间作业回放的研究，用两种方法实现了作业的动画显示。第一种方法，把机组作业记录存入Access数据库中，利用Visual Basic语言编写了机组田间作业动画回放程序，此方法简单、经济；第二种方法，把机组作业记录存入Shapefiles文件中，利用MapObjects地图组件开发了相应的作业回放软件，并可用于行走距离、作业面积的量算，此方法地理信息量丰富，功能强。本研究可应用于农机管理和教学，起到辅助作用。     

DGPS在数字农业中应用技术研究

介绍了DGPS的组成与分类,如位置差分、伪距差分和相位差分;综述了DGPS在数字农业中的应用,如进行土壤养分分布调查、监测作物产量、合理施肥、精确农业管理、卫星跟踪管理服务、农业作业机组在田间的行走导航等;建议在大规模机械化生产地区积极开展DGPS在农业中的应用研究以及相关设备的研制,促进我国农业现代化、信息化的发展。     

现代化农业中GPS卫星定位和自动导航系统的应用

农业机械在安装GPS卫星定位和自动导航系统后，在差分GPS的定位下．可对农机田间直线行走作业实现精确引导．使机组作业不重不漏，大幅度提高农机作业质量、土地利用率、机车作业效率和时间利用率．大幅度减轻农机作业劳动强度，实现机车合理调配。     

GPS导航系统在农业生产中的应用

近年来,精细农业的发展引起了人们的普遍关注,人们开始研究一种合理有效地利用农业资源进行农业作业的先进技术。因此,产生了智能化农业机械作业,实现了精确耕作、播种、施肥、灌溉、喷雾等一系列精确的定位系统。而GPS技术是实现田间行走的农业作业机械有效运行的重要手段。它有快速、灵活、高精度等优点,因此在农业机械作业中得到广泛应用。一、需求分析     

南方水田地区耕耙机组行走方法的研究

本文阐述南方水田地区的特点及现行耕耙机组的作业方法。按评定行走方法的指标与研究方法,对耕耙机组主要几种行走方法进行工作行程率的理论计算与分析,同时在福建、江西两省的社队、农场进行各种不同机组、不同田块的耕耙作业田间生产测定。根据理论计算分析与田间生产测定结果,探讨合理选择耕耙机组的行走方法,并为南方水田地区正确进行田地规划提供依据。     

基于MapObjects的农田信息采集与处理系统的研究

为解决精细农业中田间信息的采集与分析处理的问题,建立了一个基于MapObjects的农田信息采集与处理系统。该系统在VB开发环境下利用MapObjects和DGPS实现了农田信息采集功能;利用MapObjects的图形处理功能,实现了对已有农田信息的可视化分析和管理的功能。该系统的使用,为精细农业的开展,提供了一种新的信息采集和处理方法。     

农用机器人DGPS导航方法及数据采集

介绍了农用机器人DGPS的导航方法,以及利用VC++实现导航数据的采集的方法。实验结果证明农用机器人差分导航系统能大大提高GPS定位精度,达到农业生产的要求。     

马铃薯垄膜沟植播种联合机组简介

马铃薯垄膜沟植播种联合机组为利用垄沟集雨种植技术种植马铃薯的机械作业提供了技术支持,机组在田间可一次完成开沟-施肥-播种-起垄-整形-覆膜-压膜-覆土等作业,实现了垄膜沟植播种旱作农业种植模式。机组设计为两工位可折叠机架,提高了机组的运输安全性。与国内外同类型播种机相比,其结构简单,机型小巧灵活,机具价格便宜,便于制造和推广应用。     

Centimetre-precision guidance of moving implements in the open field: a simulation based on GPS measurements

High quality and sustainable agricultural production in the open field will be supported by centimetre-precision guidance of agricultural implements. In this paper, a complete guidance system is proposed and simulated using real sensor data obtained from a real time kinematic (RTK) differential global positioning system (DGPS). This type of the satellite navigation system became available commercially in 1997 and is claimed to reach cm accuracy. It uses real time kinematics to improve the accuracy of a position fix by phase comparison of the carrier signal. The simulation primarily aims to investigate the accuracy of the guidance system that can be obtained with RTK DGPS. Using real DGPS measurement errors the simulated system showed a tracking error less than 0.005 m when the PID-controller had settled.     

农用AGV视觉导航中基准线提取算法的研究

[目的]寻找用于农用AGV视觉导航曲线基准线的提取算法。[方法]针对农用AGV视觉导航基准线假定为直线而容易受作物残留物等因素的影响,引入了曲线导航基准线的提取算法。[结果]曲线导航基准线的提取算法为首先分割图像,将作物等植被和土壤等背景分离,然后在分割图像中以每行最大空隙的中点为标志点,逐行检查标志点,调整偏移较大的标志点,若与前一行标志点位移大于T,则缩小位移为t,最后连接标志点。曲线基准线提取算法更注重基准线的偏向与行进方向的一致性。[结论]在较多残留物和作物行缺乏规则的情况下,曲线基准线的大部分点都落在行进方向上,并总体向右倾斜,基本上反映了农用AGV的行进路线,提高了农用AGV导航精度。     

基于UWB定位的农业机械辅助导航系统设计与试验

【目的】低成本实现南方中小型田块中农业机械田间精确定位,降低农机操作人员劳动强度、提高农机作业效率。【方法】采用超宽带(Ultra wide band,UWB)技术对作业机械进行实时定位,通过位置解算算法,得到定位标签的三维精确位置坐标;利用位置校正算法,修正作业机械车身倾斜引起的田间定位误差;设计基于AB线的路径规划算法,实时规划作业路径并计算作业偏差;通过可视化人机交互界面为农机操作人员提供实时辅助驾驶信息。【结果】水田环境中,分别以0.5、1.0和1.5 m/s的速度沿规划路径行驶时,系统平均横向定位偏差均小于7 cm;当行驶速度大于1.0 m/s时,利用位置校正算法平均横向定位偏差降低了52.79%,标准差降低了49.82%,最大横向定位偏差降低了50.04%。搭载辅助导航系统进行田间插秧试验,各行作业轨迹与自身行拟合直线的平均横向偏差为5.90 cm,标准差为3.64 cm;各行作业轨迹与其规划直线路径的平均横向偏差为6.98 cm,标准差为4.95 cm。【结论】辅助导航系统具有较高的定位精度和良好的稳定性,成本低且通用性强,能够满足南方中小型田块中农业机械田间作业要求。研...     

采棉机跨区作业导航电子地图的制作

为了使采棉机跨区作业管理中的监控定位更为准确,采用Alos和TM遥感影像、商用电子地图为基本材料,通过对Alos影像进行矢量化并结合外业调查得到作业区域的交通、田块、POI等空间信息图层。同时对TM遥感影像进行监督分类,识别出棉花地块以及面积等信息,在MapInfo桌面GIS软件中对其进行整合得到作业区地图,再与商用电子地图进行图层叠加处理,最后制得高精度、要素丰富、适用于采棉机作业过程中导航定位的电子地图。该采棉机跨区作业导航电子地图使采棉机跨区作业过程中的监控定位更加准确,管理更加有效,既能适应大区域的调度,也能做小范围的作业定位和监控。因此,该采棉机跨区作业导航电子地图的制作方法为制作农业生产应用电子地图提供了技术手段。     

铰接转向果园割草机的设计与试验

针对丘陵山地现有果园割草机行走性能差及人员操作便捷性低等问题,设计一种铰接转向果园割草机。采用理论分析与仿真、田间试验相结合的方法,对铰接转向果园割草机进行研究。结果表明:1)铰接转向果园割草机最大行驶速度5.9 km/h,割刀转速1 450~3 850 rad/min,最小转弯半径466.4 mm,爬坡与下坡纵向极限倾覆角度分别为37.47°和60.99°,横向极限倾覆角为48.76°;2)应用Ansys workbench软件分析得到割草机车架在平地直行、平地最大角度转向、直行爬坡与直行下坡四种工况下最大变形量和最大等效应力分别为0.034 4 mm和20.06 MPa。田间试验结果表明:铰接转向果园割草机的割幅利用率为98.9%,平均碎草率85.9%,割茬高度基本符合设定高度,满足丘陵山地小地块果园作业需求。     

Procedures of soil farming allowing reduction of compaction

Evaluation of new technologies using guidance systems is very important and can help producers with choosing the right equipment for their applications. Without using satellite navigation during field operations, there is a tendency for passes to overlap. That results in waste of fuel and pesticides, longer working times and also environmental damage. When utilising satellite guidance for field operations, there is a close connection with controlled traffic farming (CTF) as well. CTF is currently a quite quickly developing farming system based on fixed layout of machinery passes across a field. Tracks precisely set out for a machine’s tyres in the field could be a tool for minimising soil compaction risk which is another threat to the environment. The purpose of this paper was to evaluate the accuracy of currently available guidance systems for agricultural machines. Real pass-to-pass errors (omissions and overlaps) in a field were measured. Consequently, comparison between observed guidance systems was made regarding final working accuracy. Further, intensity of machinery passes, percentage of wheeled area and repeated passes in fields were monitored. These measurements were made in fields under real operating conditions using a conventional tillage system with ploughing and also a conservation tillage system, both systems with randomly organized traffic. Finally, the same parameters were monitored in fields where fixed machinery tracks were used for all operations and passes but only under a conservation tillage system. Pass-to-pass accuracy was measured for the evaluation of different guidance systems. Size of missed areas or overlaps was evaluated statistically. Concerning intensity of machinery passes and total field area affected by machinery passes, the following facts were found out. The experiments with randomized traffic showed a significant difference of the parameters mentioned above between a conventional tillage system with ploughing and a conservation tillage system. Wheeled area was 86 and 64%, respectively which proves benefits of conservation tillage. The experiments with a fixed track system showed that the total run-over area by machinery tyres decreased even more (up to 31%) in comparison to randomized traffic in a field (only fields under conservation tillage system were monitored and evaluated). The following statements based on our results can be made. The navigation and therefore possibility for better accuracy of machinery passes in fields together with permanent machinery tracks utilization could help with soil condition improvement and also energy savings which would result from that. The CTF system will help with further development of a system for soil compaction protection which is currently a real necessity.     

Assessing GNSS correction signals for assisted guidance systems in agricultural vehicles

Accuracy levels achieved with differential global positioning system (DGPS) receivers in agricultural operations depend upon the quality of the correction signal. This study has assessed differential signal error from a Dedicated Base Station, OmniSTAR VBS, European Geostationary Navigation Overlay System, European reference frame-IP for internet protocol (EUREF-IP) and radio navigation satellite aided technique (RASANT). These signals were utilized in guidance assisting systems for agricultural applications, such as tillage, harvesting, planting and spraying, in which GPS receivers were used under dynamic conditions. Simulations of agricultural operations on different days and at different time slots and simultaneously recording the tractor′s geo-position from a DGPS receiver and the tractor′s geo-position from a real-time kinematic (RTK) GPS allowed the comparison of the GPS correction signals. The hardware used for tractor guidance was a lightbar (Trimble model EZ-Guide Plus) system. ANOVA statistics showed a significant difference between the accuracy of the correction signals from different sources. GPS correction signal recommendations to farmers depend upon the accuracy required for the specific operation: (a) Yield monitoring and soil sampling (<1 m) are possible with all the GPS correction signals accessed in any time slot. (b) Broadcast seeding, fertilizer and herbicide application (<0.5 m) are possible for 80% of time with OmniSTAR VBS, 40% of time with RASANT and EUREF-IP and 100% of time with a dedicated base station. (c) Transplanting and drill seeding (<0.04 m) are not possible with the accuracy correction provided by any one of the systems used in this study.     

基于离散因子的多传感器数据融合和导航线提取方法

目的 针对玉米田间路径边界模糊和形状不规则特点,普通的田间导航线提取算法在农业机器人实际应用中会出现偏差过大的问题,本文针对3~5叶期玉米田提出了基于离散因子的相机与三维激光雷达融合的导航线提取算法。方法 首先利用三维激光雷达获取玉米植株点云数据,同时将相机采集的图像利用超绿化算法和最大类间方差法自动获得绿色特征二值图像,然后将聚类分析后的点云数据投影到图像中的目标边框上,构建多传感器数据融合支持度模型进行特征识别,最后拟合所获取特征中心点即为导航基准线。结果 该算法能够很好地适应复杂环境,具有很强的抗干扰能力,单帧平均处理时间仅为95.62 ms,正确率高达95.33%。结论 该算法解决了传统算法寻找特征质心偏移、识别结果不可靠等问题,为机器人在玉米田间行走提供了可靠的、实时的导航路径。