倒车雷达

论文编号:DQ178   论文字数:12754,页数:37

摘 要
 倒车雷达，又称泊车辅助系统，或称倒车电脑警示系统。它是汽车泊车或者倒车时的安全辅助装置，由超声波传感器（俗称探头）、控制器和显示器等部分组成。它能以声音或者更为直观的显示告知驾驶员周围障碍物的情况，解除了驾驶员泊车、倒车和启动车辆时前后左右探视所引起的困扰，并帮助驾驶员扫除了视野死角和视线模糊的缺陷，提高驾驶的安全性。
 现在市面上的倒车雷达大多采用超声波测距原理，驾驶者在倒车时，将汽车的挡位推到R挡，启动倒车雷达，在控制器的控制下，由装置于车尾保险杠上的探头发送超声波，遇到障碍物，产生回波信号，传感器接收到回波信号后经控制器进行数据处理，从而计算出车体与障碍物之间的距离，判断出障碍物的位置，再由显示器显示距离并发出警示信号，从而使驾驶者倒车时不至于撞上障碍物。整个过程，驾驶者无须回头便可知车后的情况，使停车和倒车更容易、更安全。
 本文介绍了以PIC16F716单片机为核心的一种低成本、高精度、微型化，并有数字显示和声光报警功能的倒车雷达系统。
 
关键词：倒车雷达；超声波测距；PIC16F716

Abstract
Reversing radar, also known as the parking assist system, or reversing the computer alert system. It is car parking or reversing the safety of assistive devices, ultrasonic sensors (commonly known as the probe), the controller and display, and other components. It is more intuitive to voice or show that inform the driver of the barrier around the situation, lifting the driver''''s parking, and start reversing vehicles around before and after the problems caused by the visit and help the driver to remove the dead ends and vision blurred vision Deficiencies and improve driving safety.
Now the market reversing radar most of the ultrasonic ranging principle, driving in reverse, the vehicle will be pushed to the Shift R block to start reversing radar, under the control of the controller, installed in the rear bumper on the probe Send ultrasound, encounter obstacles, a signal, sensors after receiving the signal controller for data processing, thereby calculate the body and the distance between the obstructions, determine the location of obstructions, and then from display Show distance and issued warning signal, so that drivers will not hit obstacles when reversing. The whole process, drivers know they do not have to turn around the situation after the car, stopping and reversing it easier and more secure.
This paper introduces a low cost, high-accuracy, micro-miniaturization, digital display and acousto-optics alarm intelligent parking radar that based on MCU PIC16F716.

Key words：Reversing radar；ultrasonic ranging；PIC16F716

目 录
摘 要 I
Abstract II
1 绪 论 1
1.1选题的目的 1
1.2测距现状 1
1.3国内现状 2
2 超声波测距 4
2.1超声波测距的基本原理 4
2.2超声波传感器 4
2.2.1超声波传感器种类及结构 4
2.2.2常用超声波传感器 5
3 总体设计 7
3.1探测方位 7
3.2整体设计思路 7
3.3系统工作流程 8
4 硬件设计 9
4.1单片机控制模块 9
4.1.1 PIC16F716单片机内核特征 9
4.1.2 TIMER1 模块 12
4.2 电源模块 14
4.2.1倒车灯电源输入保护电路 14
4.2.2 DC-DC 降压电路 14
4.2.3 7.5-5V MCU工作电源 16
4.2.4 24-12V供中周驱动电源 16
4.3超声波发射模块 17
4.3.1测距的方案论证 17
4.3.2超声波发送模块设计比较 17
4.3.2 ULN2003驱动芯片 18
4.4超声波接收模块 20
4.4.1多路选择开关 20
4.4.2接收放大滤波整形 20
4.5 显示报警模块 21
4.5.1 LCD显示 21
4.5.2 语音报警 23
5 软件设计 24
5.1超声波发送接收 24
5.2软件设计 25
5.3程序时间分析 26
6 测试与分析 27
6.1超声波波束对探测目标的入射角的影响 27
6.2超声波回波声强弱的影响 27
6.3超声波传播速度对测距的影响 27
7 结束语 29
致谢 30
参考文献 31
附录 32