【作者】 周晶；

【导师】 鲁植雄；

【作者基本信息】 南京农业大学 ， 工程硕士（专业学位）， 2015， 硕士

【摘要】 新型农业机械在开发和设计过程中,受农田环境的不可控、驱动设备的振动以及农时天气等试验条件限制,发展相对缓慢。在车辆地面系统力学的研究中,拖拉机的振动以及土壤参数的不确定性也制约着该学科发展。故本文在了解国内外土槽试验台车系统的历史发展与研究现状后,结合实验室现有条件和资源,设计了一台操作性较好、精确度较高的土槽试验台车系统。该土槽试验台车系统集机械、液压、PLC控制技术、LabVIEW虚拟仪器技术于一体,模拟中小型拖拉机工作方式。驱动能力大、控制准确可靠、测试灵活方便,采集存储数据连贯。系统可用于各类农业机械的样机模拟试验和性能测试分析试验,如犁耕试验、旋耕试验等;进行轮胎与地面耦合的相关试验,测试轮胎运行过程中受力情况,胎面变形情况,验证轮胎理论模型等。也可在教学过程中用作为演示、示范模型。台车系统主要由槽体、牵引车和双轮试验装置组成。土槽体用于盛放试验土壤,按照实际田间土层分布,土壤厚度可达80cm。土槽同时作为牵引车运行轨道,牵引车在槽体的轨道上运行,具有加速阶段、有效阶段和减速阶段。牵引车速度范围为0-10m/s,牵引功率22kW,动力输出轴转速为0-1000r/min,输出功率7.5kW。前后工作装置分别可提供10kN的加载力,用于提升或下降工作装置。双轮试验系统用于模拟不同工况下轮胎的运行情况,可控制胎压、滑转率、车速、垂直载荷等因素进行试验,分析轮胎受力、验证理论模型。本文对这这三个主体部分分别进行设计。首先,基于农机系实验室条件设计土槽体方案,包括给排水方案、轨道放置和土层布置。其次,设计试验牵引车的总体方案。使用三维建模软件SolidWorks建立试验台车系统的整车结构和零部件图。设计机械部分,对车架进行设计与仿真;设计并校核带传动、齿轮传动和链传动的;重点设计传动轴、动力输出轴的结构,使用Ansys进行静力结构分析;选型轴承、键、联轴器等零部件。计算液压站主要参数,绘制液压油路原理图。最后利用二维设计软件导出加工图纸。再次,确定电气控制部分功能以及测试系统的功能模块,设计控制系统流程,选型控制系统硬件,分配输入输出端口以及设计外围电路,利用SIMTAIC编程软件STEP7编写控制梯形图,以及设计人机交互控制界面。对测试系统硬件进行选型,分析测试原理,重点对轮胎以及犁体六分力测力机构进行分析,使用NI系列产品设计了数据采集系统和测试界面。最后,对双轮试验装置进行设计,包括带传动、齿轮传动的设计与校核,传动轴的设计与仿真以及其他零部件的选型等。对试验装置的垂直加载结构进行设计和仿真,并设计了平衡小轮。更多还原

【Abstract】 The design and exploitation of new agricultural mechinaries goes relatively slowly because of the restriction of test conditions,such as the uncontrollable of farmland environment,the vibration of drive devices,the farming season and weather,et al.The research of ground vehicle system mechanics is also restricted by the vibration of tractors and the uncertainty of soil parameters.So after learning the historical development and research status of soli bin facility system at home and abroad,a soli bin facility system which can be easily operatead and have a high accuracy considering the current conditions and resources of our laboratory are designed.The soil bin facility collects several advanced technology including mechanism,hydraumatic,PLC,LabVIEW to imitate different working conditions of medium and small sized tractors.It has a great ability of driving force,controller,testing system and data processing many kinds of agricultural machinery tests can be taken on this facility,such as the plow-tillage test;rotary cultivator test;seed drills test;Spraying machine test and others.It also can be used as a demonstration on teaching.We can get the parameters’ alterations of tire-soil coupling system.It consists of a soil bin;a test motor tractor and the double-wheel test device.The soil is placed in the soil bin.Soil thickness has reached to 80cm,according to the actual field soil distribution.The soil bin is used as a track to move the test motor tractor,which has the acceleration stage,the effective stage and deceleration stage.The test motor tractor’s velocity is in the range of 0-10m/s and the traction power is up to 22kW.The velocity of power output shaft speed is the range of 0-1000r/min,the power is up to 7.5kW.The front and rear working device can provide loading force of 10kN to rise and lower the testing device.The double-wheel test device is used to imitate the tires’ operation under different working conditions.We can analyze the tire stress and verify the theoretical model with different factors of tire pressure,slippage rate,speed and vertical load.There are three main parts in this paper as follows.Firstly,the soil bin scheme was designed based on the currrnt conditions of agricultural mechanical laboratory,includes the water supply and drainage construction,orbital place and soil layout.Secondly,the overall structure of soil bin facility was designed.The totally structure and parts drawings were drawn by the 3D modeling software Soildworks.The subject of mechanical parts including carriage,belt drive,gear drive,chain drive were designed and simulated.The design of transmission shaft and The power-output shaft is the important part in the paper.The The structural static analysis of shaft is based on the Ansys.And then I choosed the models of other parts.The main parameters of the hydraulic part were calculated and the principle diagram of the hydraulic system was gived.Processing drawings and technical requirements were drawn by 2D design software AutoCAD.Thirdly,the controller and test system’s functions were determined.The following works have been done,to design the controller processing,to select the hardware,to distribute the input and output ports,to design circuit,to compile ladder diagram by STEP7,to design interface by HMI WinCC flexible.Then the hardware of testing system was selected.I analyze the testing principle,especially of the six component force measuring mechanism of tire and plough.And I design the data acquisition system and testing interface using the NI series products.Lastly,I design the double-wheel test device,including the design and simulation of belt drive,gear drive transmission shaft and other parts.The vertical loading mechanism and the balance wheel mechanism were designed and simulated.更多还原