目 录
摘 要 ......................................................................................................................................................I
ABSTRACT ............................................................................................................................................II
1 绪论......................................................................................................................................................1
1.1 设计的意义和要求..................................................................................................................1
1.2 目前国内倒车雷达的发展现状...............................................................................................1
2 总体设计方案......................................................................................................................................3
2.1 超声波测距..............................................................................................................................3
2.1.1 超声波测距原理..........................................................................................................3
2.1.2 测量与控制方法...........................................................................................................4
2.1.3 理论计算.......................................................................................................................4
2.1.4 影响精度的因素分析..................................................................................................5
1 温度误差..............................................................................................................................5
2 时间误差..............................................................................................................................6
2.1.5 提高精度的方案及系统设计......................................................................................6
2.1.6 测量盲区......................................................................................................................7
2.2 超声波传感器..........................................................................................................................8
2.2.1 超声波传感器原理及结构...........................................................................................8
2.2.2 超声波传感器的特性...................................................................................................9
2.2.3 超声波传感器的应用................................................................................................11
3 硬件设计............................................................................................................................................13
3.1 超声波发射电路....................................................................................................................13
3.2 超声波检测接收电路............................................................................................................14
3.3 超声波显示及控制部分电路................................................................................................15
3.3.1 AT89C51 单片机的原理及工作特点.........................................................................15
3.3.2 单片机实现测距原理.................................................................................................16
3.3.3 稳压电源电路............................................................................................................16
3.3.4 显示电路原理............................................................................................................17
3.3.5 温度测量电路............................................................................................................20
3.3.6 键盘控制电路.............................................................................................................20
4 软件设计.............................................................................................................................................21
4.1 软件设计的要求....................................................................................................................22
4.2 超声波测距的算法设计........................................................................................................22
4.3 主程序....................................................................................................................................23
4.4 超声波发送及接收中断程序.................................................................................................25
4.5 显示子程序和蜂鸣报警子程序............................................................................................27
5 系统的软硬件调试............................................................................................................................27
结 论..................................................................................................................................................29
参考文献................................................................................................................................................30
谢 辞..................................................................................................................................................30
附录 1 超声波倒车雷达系统的原理图...............................................................................................31
附录 2 程序清单...................................................................................................................................33
