【作者】 姚亚萍；

【导师】 吕新民；

【作者基本信息】 西北农林科技大学 ， 机械设计及理论， 2010， 硕士

【摘要】 我国是农业大国,要想发展农业规模化和精细化生产就离不开土地平整技术。田块的平整度越高,越有利于受水受肥均匀,有利于出苗整齐,有利于提高作物产量,有利于农业机械化的实现。激光平地技术是现有的最先进、最有效的土地精平技术,平地后能够实现1~2cm的平整精度。但是国外激光平地机价格昂贵,而国内激光平地技术仍不完善,这些都不利于激光平地技术在国内的推广。因此,提出和设计一种符合中国国情的激光控制平地系统具有重要的现实意义和较高的科学研究价值。(1)分析了激光控制平地系统的总体需求,根据不同平地铲的宽度,提出单接收器系统和双接收器系统两种总体系统方案设计,解决由于平地铲过宽造成的倾斜问题。(2)分析研究了激光产生的原理、激光束准直压缩系统和激光器构成的理论,分析和比较国内外用于平地机的激光器的性能指标,选择JP300型国产激光扫平仪作为系统的激光发射器,在满足工作精度要求的同时降低成本。(3)研究和设计了激光接受装置。在理论分析的基础上,采用空间滤波、光谱滤波和电路滤波分三步进行背景噪声处理,滤除太阳辐射等背景光对激光的影响;设计了一种22×4的变间距光电池阵列作为激光接收器的光电传感器;设计了信号处理电路,将光信号转换成TTL电平信号,运用PROTEUS完成硬件电路仿真;完成了单片机外围电路设计和软件编程,实现了位置偏差信号的识别和编码输出。(4)研究和设计了激光控制器。分析信号传输的距离对传输信号的影响,使用RS-485总线技术完成了双机串口通信,实现了接收器与控制器之间位置偏差信号的传送;选择AT89C51单片机作为控制器的微处理器,利用PROTEUS设计了单片机外围电路,使用KEIL C进行单片机C语言编程,通过对位置偏差信号识别,实时控制平地铲的移动方向与幅度。设计完成的激光控制平地系统,可以实现土地自动整平,平地精度1cm左右,工作范围为300m,工作高度范围是20.9cm,基本满足设计要求。更多还原

【Abstract】 China is a large agricultural country, in order to develop the production scale of the agriculture; we must develop the land leveling technology. The higher flatness of the land, the more uniform by the watering and the fertilizing, it is good at emergence uniformity, it helps to improve crop yield and help the realization of agricultural mechanization. Laser controlled land leveling system is the most advanced and effective precise land leveling technology. After the operation, the ground can be achieved the accuracy of 1 ~ 2cm. However, the laser graders is expensive in abroad, and domestic laser leveling technology is still not perfect, these are hider the technology develop in china. Therefore, proposing and designing a laser-controlled land leveling system, which can used in China, has important practical significance and a high scientific value.(1)According to demands of the whole system, this paper proposed a system with single laser receiver and another system with two laser receivers to fitness the different widths of flat shovels, to solve the problem of the inclination because of the wide of the flat shovel.(2)Analyzed and compared the LASER used in land leveling system at home and abroad, this paper chose a homemade laser swinger system as laser transmitters to meet the operating precision in order to reduce costs.(3) Researched and designed a laser receiving device. Based on theoretical analysis, using spatial filtering, spectral filtering and circuit filtering deal with background noise in three steps, it can filter solar radiation and other background light on the impact of laser; Designed a 22×4 array of changes in pitch as the laser light battery receiver photoelectric sensors; Designed the signal processing circuit, it can change the light signal into a TTL level signal, and used PROTUES to complete the hardware emulation; Completed a peripheral circuit and software programming design of MCU, achieved a position error signal recognition and code output.(4) Researched and designed a laser controller. Analysis the distance impaction of the signal transmission, using the RS-485 bus to complete the two-MCU serial communication, realized the position signal transmission between the receiver and controller; Chose AT89C51 microcontroller as the controller microprocessor, used PROTUES to design external circuits, used KEIL C to write the programming, through the position error signal recognition, realized the real-time control with the moving direction and magnitude of the flat shovel.The laser controlled land leveling system can realize automatic land leveling, the precision can achieve around 1cm, the working area is 300m, working height range is 20.9cm, meet the requirements of design.更多还原