【作者】 苑严伟；

【导师】 张小超；

【作者基本信息】 中国农业机械化科学研究院 ， 机械设计及理论， 2010， 博士

【摘要】 传统的农机试验需要反复设计、制造和改进,且受季节、农时和天气的限制,研发周期长,成本高。基于虚拟现实技术的农机仿真与虚拟试验能缩短研发周期,降低研发成本,是实现农业机械化和现代化的关键。本文研究了数字农业典型智能化农业机械虚拟试验方法；设计了田间工况模拟平台；实现了实体样机与虚拟农田的交互控制；并对平移式喷灌机、采摘机器人手臂以及无人飞行器等典型智能化农业装备进行仿真。具体内容为以下七个方面：1.提出基于改良随机数发生器分形理论的农田大尺度虚拟场景建模方法,根据农田数字地图以及地势信息,加上作物生长情况以,产生三维虚拟环境,建立了旱田和水田三维仿真场景。2.首次提出变分辨率的虚拟农田驱动方法,实现三维农田近视点细节展示和远视点的快速漫游,提高了农田场景展示精度和漫游速度,研究碰撞检测技术,实现了农机模型在虚拟农田内的作业仿真。3.建立田间工况模拟平台,实现农机在田间工作时振动、转向、侧翻和俯仰等四个自由度的动作模拟,研究智能化农机虚拟试验技术,实现了典型农机实体、农机三维模型以及虚拟农田的交互控制和仿真,为农业机械室内试验提供了条件。4.提出平移式喷灌机同步行走仿真试验方法。建立关键零部件的三维模型库,完成整机的虚拟装配。根据受力模型,结合碰撞检测技术,实现对整机模型的运动学仿真。提出的摆角归零同步反馈控制方法,通过仿真实验,验证与传统的百分率计时器控制方法的横向雨量分布均匀度的差异。5.提出基于粒子系统的水量分布最优化方法。根据单喷头室内喷洒试验,建立喷洒模型,考虑受重力和空气阻力的影响以及破碎和蒸发等因素,用粒子系统模拟水珠的运动轨迹以及落地点的位置,统计各微小区域内雨量分布。通过仿真实验,计算典型喷头纵向雨量分布最优时的间距配置。6.借助于OpenGL库函数,对机器人的机械臂的运动控制进行了虚拟仿真,提出了基于有限域信息素自适应更新的改进蚁群算法,将苹果采摘的路径规划问题转化三维的TSP问题进行求解,避免了基本蚁群算法求解过程中的早熟和局部收敛的问题。7.为了远程控制无人机起降和监视无人机飞行状况,提出了基于虚拟现实技术的无人机监控方法。根据飞行器参数对飞机模型进行驱动,给出反馈信号,控制飞行器按预定路线飞行。仿真实验表明对飞行器的远程导航控制是可行的。更多还原

【Abstract】 The traditional experiment of agricultural machinery requires repeated design, manufacture and amelioration, and is restricted by weather and farming season, which wastes lots of time, human resouse and financial resource. Virtual reality technology based intellegent agricultural equipment experiment can reduce development cycles and product cost, which is the key technology to realize agricultural mechanization and modernization. In this paper, virtual experiment method used in agricultural machinery was studied; field condition simulation platform was designed; the interaction simulation between machine and virtual field was done; large-scale irrigation, apple picking robot and unmanned aircruft vehicle were simulated. The specific contents are as follows:1. Advanced a new method of improved random number generator based fractal theorym to build large scale field scenes. According to digital maps, farmland terrain, combined with field crops, build three-dimensional models of field virtual scene.2. Advanced a new method of alterable-resolution-based virtual field driving, realized displaying detail models at near viewpoint, and fast ramble at far viewpoint, which improved the terrain precision and rambling speed. Studied collision detection technology, simulated exercise of agricultural machinary in virtual field.3. Built a field condition simulation platform, realized the simulation of tractor’s posture (vibration, steering, roll, and pitch) while walking in the field. Studied virtual experiment technology of intellegent agricultural machinery, realized the interaction of mechinery, three-dimensional models and virtual scenes, make it possible for agricultural experiment in-door.4. Advanced the synchronously driving method of linear move irritator in virtual experiment. Build three-dimension models of the irrigation system departments, assembled the models to a whole irrigator. According to force model and collision detection technology, realized the kinematics simulation. Advanced angle-to-zero-based feedback control method, test water distribution in landscape orientation between the new method and traditional percentage timer based control method.5. Advanced particle-system-based water distribution optimization method. Built water insufflation models according to in-door irrigation experiment by single sprayer. Consider the factors of gravity, resistance by air, crash and evaporation, simulated tracks of the water bead with particle system, then counted the water distribution in every small field. By simulation, calculated the optimal distance between each sprayer that got the best wather distribution of each type of sprayers.6. Recur to OpenGL function, simulated the control of robot arm moving process when picking, advanced an improved ant colony algorithm. Turn route planning of apple harvesting three-dimentional travel salesman problem, which overcomed the problem of premature convergence and local convergence during the calculation. 7. To take off and land the unmanned aircraft vehicle remotely and monitor it’s gesture, advanced a virtual-reality-based UAV moisture method. Drived the plane model in virtual circumstance according to the data sent by the sensors fixed on the plane, then fed back the errors to adjust the plane’s gesture in order that the plane can fly in the route we give. Simulation experiment shew that the control way was suitable.更多还原