【作者】 韩云霞；

【导师】 张书慧；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2004， 硕士

【摘要】 精确农业技术研究发展的驱动力是对农业耕作中发现的作物生长环境和实际收获产量分布的空间差异性的认识，其核心是 GPS、GIS、RS 等技术支持下的精确定位与变量作业。化肥是农业高产和增产的主要投入要素，化肥成本在农业总成本中占了较大的比重，而且化肥的投入量与利用率直接影响农业产出、农民收入和环境质量。变量施肥适应不同地区、不同作物、不同土壤和不同作物生长环境的需要进行全面平衡施肥，提高肥料利用率，具有明显的经济和环境效益。我国的化肥投入存在结构不合理、肥料平均利用率低、肥料的增产效益没能充分发挥等问题。在变量施肥技术研究方面，我国基本是引进国外先进技术设备，进行消化、吸收的跟踪研究。因此，研究和开发自动变量施肥技术，对发展符合我国国情的变量施肥技术和实现农业可持续发展具有重要的理论意义和实用价值。本文结合吉林省科技发展基金“精确农业自动变量施肥技术研究”和吉林省农业开发综合办公室“精确农业变量施肥技术示范”课题，进行了 2BFJ-6 型自动变量施肥机控制系统设计开发和地块网格识别模拟设计等研究，主要工作和结果如下：(1) 制订控制方案和控制模型。针对我国农村现有的生产条件，同时充分考虑到农业机械所需的可靠性，自动变量施肥控制系统采取手动和自动两种控制方案。在深入分析影响施肥的主要因素和施肥控制原理的基础上，确定了自动变量施肥步进电机转速控制模型，为实现自动变量控制建立理论基础。(2) 开发以单片机为核心的控制系统作为自动变量施肥执行机构的控制器。分析了控制系统的的输入、输出和通信等要求，设计系统的结构，确定了 I<WP=75>吉林大学硕士学位论文硬件电路主要包括 DGPS 信号接收、速度传感器信号接收、键盘接收、IC 卡接口、控制脉冲输出、显示及报警等几个部分。经过试验验证，系统比较稳定、可靠，达到使用要求。 (3) 控制程序设计。使用单片机开发的高级语言工具 C51 编写控制程序，实现手动和自动两种控制方式的变量施肥。在自动控制方式下，完成了对 DGPS位置和速度信息的提取，实现对任意试验地块网格的准确识别和施肥量的正确提取，输出脉冲控制电机转速，实现变量施肥作业。在手动方式下，实现了对地轮转速传感器脉冲信号和键盘值的读取与处理，从而输出电机转速控制排肥轴完成变量施肥作业。同时解决了控制系统与计算机的通信、显示观察及电机斜坡启动等问题。程序具有简单高效、结构清晰和一定的通用性等特点。 (4) 地块网格识别模拟控制程序设计。基于控制系统在研究开发过程中的实际需要，针对自动变量施肥控制系统的地块网格识别部分，使用可视化工具软件 Visual Basic 结合 MapX 开发了地块网格识别模拟控制程序。程序实现了以鼠标的移动模拟施肥机行进过程、识别施肥机所处当前地块网格名称、查询对应的施肥量并显示等功能，同时以 DGPS 的数据格式输出当前点的地理位置、模拟速度等信息，通过串行端口提供给控制器，使控制系统对地块网格进行正确的模拟识别。模拟程序为控制系统的研究改进和调试工作带来方便，缩短了系统的开发和实验周期。 (5) 排肥机构标定实验。分别对六行和两行自动变量施肥机进行了排肥机构标定实验。分析得出排肥轴转速和平均排肥量之间高度线性相关，通过误差分析表明各排肥器排肥均匀性和稳定性能够满足要求。对标定实验数据拟合得出排肥量与排肥轴转速之间的关系曲线。对拟合结果进行评价并综合考虑控制精度和程序设计的要求，选用一次方程用于施肥控制。综合机具前进速度 v、排肥轴转速 n 对施肥量 Q 的影响，得出三者的数学关系式。 (6) 自动变量施肥控制系统田间试验。在使用 DGPS 和地轮传感器检测机具前进速度两种试验的情况下，通过对试验中存在的主要误差因素进行分析，结果表明，由于 DGPS 信号中速度值的误差和地轮打滑率的存在，使变量施肥的精度不够理想。 (7) 完成了自动变量施肥控制系统改进实验。综合考虑影响控制系统精度的误差因素，对控制程序和施肥机构做相应修正和调整。系统改进后，分别进行手动和自动两种控制方式的施肥试验。试验结果表明，施肥精度得到提高，II<WP=76>摘 要手动和自动控制方式下，误差分别小于 5%和 7%，取得理想的控制精度。本文研究的是基于地图的自动变量施肥控制系统，可自动接收 DGPS 信号，获得施肥机位置和速度信息，根据施肥决策数据实现变量施肥控制。通过手动和自动两种控制模式，施肥量均可以实现 80～500kg/ha 范围之内的调整，电机转速范围为 10～200rpm。系统具有结构简单、操作方便易学、施肥量变化范围大、控制性能比较稳定可靠、控制精度理想等特点。此外，本系统借鉴国内外研究经验，以自主开发为主，成本较低，而且可适用于不同型号的变量施肥机控制，适合我国国情，有利于促进变量施肥技术的实施及在中国的推广应用。更多还原

【Abstract】 The study and development of the technology of Precision Agriculture(PA) isderived by recognition of difference from crop’s growth environment and yield inthe cause of agricultural cultivation, whose core is precision positioning andvariable rate application supported by GPS, GIS and RS, etc. The fertilizer is mainelements of agricultural high yield and increase production, and the cost of fertilizertakes greater parts among total cost. The input and the utilization ratio of fertilizereffects agricultural output, peasant’s income and environmental quality directly.Variable Rate Fertilization (VRF) is suitable for different needs for areas, crops,soils and crops growth environment. With balance applying fertilizer, VRF canimprove the fertilizer utilization ratio, and has obvious economic and environmentalbenefits. Inputting fertilizer has some problems in our country, such as unreasonablestructure, low average utilization ratio of fertilizer, failing to give full play offertilizer in increasing production benefit. In researching of VRF, it is main work tointroduce foreign advanced equipments to track, digest and absorb. So, it isnecessary to study and to develop the technology of VRF according to our nationalconditions, which has important theoretical meaning and practical value to realizeagricultural sustainable developments. The paper is supported by the subject of “Study on technology of automaticVRF in PA” founded by Jilin Province development of science and technology andthe project of “Technology of VRF in PA” supported by Jilin Province agriculturedevelopment general office. This paper introduces the design of automatic controlsystem of 2BFJ - 6 variable rate fertilizer applicator and the simulation of field gridsIV<WP=78>Abstractdiscern etc. The main work and results are as followed:(1) Control project and model of automatic VRF are established. To the existing working condition of countryside in our country, and fully considering the reliability that agricultural machinery needs, manual and automatic methods of control are adopted in the automatic control systems of VRF. On the base of analyzing the main elements that effect fertilizer and the rule of control fertilization, the control model of step motor’s rotary speed in automatic VRF is confirmed. It sets up theoretical foundation for automatic controls of VRF.(2) SCM control system is developed as controller of automatic VRF executive body. According to the requests of control system, the input and output of system and the communication are analyzed, and the structure of control system is designed. The hardware electric circuit of SCM control system is confirmed, which includes receiving DGPS signals, receiving sensor signal of tractor velocity, keyboard inputting, IC card interface, pulse output of step motor, displaying screen and warning etc. Verified by the experiment, the control system is relatively steady, reliable, and meets the request of using.(3) Design program of control system. The program is written by using high-level language tool C51 that used in SCM development. It can realize VRF by means of manual and automatic control. In automatic method of control, program has finished receiving positional and velocity information from GPS receiver working in mode of DGPS. It can discern the field grids accurately and search quality of fertilizer per hectare correctly, and then it outputs the pulse to drive step motor and completes VRF. In manual method of control, program can receive and deal with sensor pulse signal and keyboard characters. Then it outputs the pulse to drive step motor and completes VRF. At the same time program solves these problems such as the communication between control system and computer, displaying the results, continuous start of step motor, and so on. In addition, program has many properties such as high-efficient, simple and c更多还原