收割机行走系统

辽宁科技大学本科生毕业设计 第I页

收割机行走速度控制系统设计

摘要

联合收割机在农业生产中发挥着越来越重要的作用。然而，我国联合收割机仍存在作业质量差、效率低、故障多等问题。性能好、自动化智能化程度高的联合收割机将成为今后研制开发的一个方向。传统的联合收割机行走速度调节是由驾驶人员通过档位和液压无级变速器来实现。操作比较复杂，速度控制不精确不及时。联合收割机在作业过程中，行走速度是影响其生产率和作业质量的重要因素。要充分地发挥联合收割机的效率，要求在作业过程中保持较高的行走速度。但行走速度受到诸多因素的限制，它对拨禾轮的工作速度，对切割器的切割质量，对脱粒、分离和清选质量，对发动机功率及工作部件功率等都有很大的影响 。行走速度太快会使喂入量过大，从而导致脱粒装置超载，发生故障，或造成其它工作部件损坏。同时，过大的喂人量也会使分离损失指数增加而造成损失量超标。可见，对行走速度进行控制是非常有必要的。为此，本文根据联合收割机行走速度的控制要求，运用单片机控制技术，结合自动控制理论设计了一套联合收割机行走速度自动控制系统。该系统可以根据喂入量的变化实时控制收割机的行走速度，使其保持在高效稳定的工作状态。本文首先对控制系统的总体方案进行了分析，提出采用电动机作为收割机行走驱动装置，易于实现速度的自动控制，与传统的机械液压式速度控制系统相比，结构简单，控制更精确。

关键词：联合收割机；自动控制；喂入量；行走速度

辽宁科技大学本科生毕业设计 第II页

Abstract

Combine in agricultural production is playing an increasingly important role. However, there is still work in China combine poor quality, low efficiency, fault many other issues. Good performance, a high degree of automation intelligence combine to become a direction for future research and development. Combine a traditional walking speed of adjustment by the driver through the stalls and the hydraulic continuously variable transmission to achieve. Operation is relatively complex, imprecise speed control is not timely. Combine the operating process, the walking speed affect the productivity and work quality of the important factors. We should give full play to combine the efficiency of the process required to maintain a high operating speed of walking. But the walking speed by many factors, it allocated Wo round pace of work, on the cutter's cutting quality of the threshing, separation and cleaning quality of the work on the engine power and the power of such components has a significant impact n. Walking too fast will feed people excessive, leading to overloading of threshing equipment, failure, or cause damage to other parts of the work. Meanwhile, the excessive amount of feed were also isolated loss index will increase the amount excessive losses. Can be seen on the walking speed control is necessary. Therefore, this article combines walking speed under the control requirements, the use of microcomputer control technology, automatic control theory and design combined with a combine harvester travel speed control system. The system can feed real-time control of volume changes in walking speed of the harvester, so as to maintain stability in the efficient working condition. Firstly, the overall scheme of the control system were analyzed, with motor running as the harvester drive, easy to implement speed control, with the traditional mechanical-hydraulic speed control system, structure, simple control more precise.

Keywords：Combine; control; feed rate; walking speed

辽宁科技大学本科生毕业设计 第III页

目录

摘要 ........................................................................................................................................... I Abstract .................................................................................................................................... II 1 绪论 ...................................................................................................................................... 1

1.1 选题的目的和意义 ...................................................................................................... 1 1.2 研究现状和动态 .......................................................................................................... 2

1.2.1 国外研究现状 ..................................................................................................... 2 1.2.2 国内研究现状 ..................................................................................................... 3 1.3 本设计研究内容 .......................................................................................................... 4 1.4 技术路线 ...................................................................................................................... 4

2 控制系统的硬件设计 ..................................................................................................... 6

2.1 喂入量传感器的选择分析 .......................................................................................... 6

2.1.1 喂入量传感器的应用现状 ................................................................................. 6 2.1.2 喂入量测试方法的选择分析 ............................................................................. 7 2.2 行走速度测量传感器的选择 ...................................................................................... 7

2.2.1 转速测量方法的选择 ......................................................................................... 7 2.2.2 开关型霍尔传感器的原理 ................................................................................. 8 2.2.3 传感器整形电路设计 ......................................................................................... 9 2.3 单片机硬件系统的选择及配置 .................................................................................. 9

2.3.1 单片机的选择 ..................................................................................................... 9 2.3.2 AT89C51单片机的性能与引脚功能介绍 .................................................... 10 2.3.3 系统I/O口的扩展 ............................................................................................ 13 2.3.4 8255A芯片的引脚配置及功能 ..................................................................... 13 2.3.5 8255A芯片与AT89C51的接口电路设计 .................................................... 14 2.3.6 振荡器电路设计 ............................................................................................... 15 2.3.7 复位电路设计 ................................................................................................... 16 2.4 存储器的配置 ............................................................................................................ 17

辽宁科技大学本科生毕业设计 第IV页

2.5 数据采集电路的设计 ................................................................................................ 18

2.5.1 模数转换器的选择 ........................................................................................... 18 2.5.2 ADC0809引脚介绍 ........................................................................................ 18 2.5. 3 ADC0809与单片机AT89C51的接口电路设计 ......................................... 19 2.5.4 行走速度测量电路设计 ................................................................................... 21 2.6 显示系统电路设计 .................................................................................................... 21 2.7输出控制电路设计 ..................................................................................................... 23

2.7.1 调速方案的选择 ............................................................................................... 23 2.7.2 输出控制电路设计 ........................................................................................... 24 2.8 本章小结 .................................................................................................................... 26

3 数据处理及控制系统的软件设计 ............................................................................ 27

3.1 数学标度变换与标定 ................................................................................................ 27 3.2 数字滤波算法 ............................................................................................................ 28 3.3 控制系统软件设计 .................................................................................................... 28

3.3.1 主程序设计 ....................................................................................................... 30 3.3.2 喂入量数据采集子程序 ................................................................................... 31 3.3.3 速度显示子程序 ............................................................................................... 33 3.3.4 控制输出子程序 ............................................................................................... 34 3.4 本章小结 .................................................................................................................... 35

4 控制器抗干扰设计 ........................................................................................................ 37

4.1 形成干扰的基本要素 ................................................................................................ 37 4.2 干扰的分类 ............................................................................................................... 37 4.3 干扰的耦合方式 ........................................................................................................ 38 4.4 常用硬件抗干扰技术 ................................................................................................ 38

4.4.1 抑制干扰源 ....................................................................................................... 38 4.4.2 切断干扰传播路径 ........................................................................................... 39 4.4.3 提高敏感器件的抗干扰性能 ........................................................................... 40 4.5硬件抗干扰 ................................................................................................................. 40