汽车倒车防撞系统设计

电子信息工程论文编号:DZXX330  论文字数:25296,页数:47  附开题报告

目    录
第1章  绪论 1
 1.1  超声检测发展综述 1
 1.2  论文主要内容和章节安排 3
第2章  选题背景 5
 2.1  超声波传感器介绍 5
 2.2  超声波检测概述 7
 2.2.1  超声探伤 8
 2.3  超声测距原理及实现  9
第3章  方案论证 10
 3.1  超声波测距系统总体方案 10
 3.2  系统主要参数考虑 11
 3.2.1  传感器指向角 11
 3.2.2  测距仪的工作频率 12
 3.2.3  声速 12
 3.2.4  发射脉冲宽度 12
 3.2.5  测量盲区 13
第4章  过程论述 14
 4.1  发射接收电路方案设计 14
 4.2  显示报警单元方案设计 22
 4.2.1  系统显示电路设计 22
 4.2.2  系统报警电路设计 23
 4.3  单片机复位电路 24
 4.4  时钟电路 25
 4.5  稳压电源 25
 4.6  单片机硬件介绍 27
 4.6.1  单片机AT89C51介绍 27
 4.6.2  8155芯片介绍 28
 4.6.3  74LS244芯片介绍 29
 4.6.4  74LS06芯片介绍  30
 4.7  运算放大器 31
 4.8  LM567芯片介绍 32
 4.9  探头UCM介绍  33
 4.10  系统软件结构  34
 4.10.1  主程序  34
 4.10.2  显示子程序和蜂鸣报警子程序  37
第5章  结果分析 39
 5.1  误差产生原因分析 39
 5.1.1  温度对超声声速的影响 39
 5.1.2  回波检测对时间测量的影响 40
 5.1.3  超声传感器所加脉冲电压对测量范围和精度的影响 40
 5.2  针对误差产生原因的系统改进方案 40
参考文献 42
致谢 43

 【摘要】随着社会经济的发展交通运输业日益兴旺，汽车的数量在大副攀升。交通拥挤状况也日趋严重，撞车事件屡屡发生，造成了不可避免的人身伤亡和经济损失，针对这种情况，设计一种响应快，可靠性高且较为经济的汽车防撞预警系统势在必行，超声波测距法是最常见的一种距离测距方法，本文介绍的就是利用超声波测距法设计的一种倒车防撞报警系统。
 论文的内容是基于AT89C51单片机倒车防撞系统的设计，主要是利用超声波的特点和优势，将超声波测距系统和AT89C51单片机结合于一体，设计出一种基于AT89C51单片机的倒车防撞报警系统。该系统采用软、硬件结合的方法，具有模块化和多用化的特点。
 论文概述了超声波检测的发展及基本原理，阐述了超声波传感器的原理及特性。对于系统的一些主要参数进行了讨论，并且在介绍超声波测距系统功能的基础上，提出了系统的总体构成。通过多种发射接收电路设计方案比较，得出了最佳设计方案，并对系统各个设计单元的原理进行了介绍。对组成各系统电路的芯片进行了介绍，并阐述了它们的工作原理。论文介绍了系统的软件结构，通过编程来实现系统功能。最后，通过对系统的误差分析，给出了系统的改进方案。
 
 【关键字】：单片机  超声波  AT89C51  距离测量  传感器
 
 

Abstract

 Is day by day prosperous along with the social economy development transportation shipping industry, the automobile quantity climbs in the first mate. Traffic congestion condition also day by day serious, the collision event occurred repeatedly, has caused the inevitable person casualties and the economic loss, in view of this kind of situation, designed one kind to respond quickly, the reliability was high also a more economical automobile guards against hits the early warning system imperative, the ultrasonic wave range finding was the most common one distance range finder method, this article introduces is guards against using the ultrasonic wave range finding design one kind of back-draft hits the alarm system.
 The paper is based on the contents of the AT89C51 monolithic integrated circuit reverse collision avoidance system design, mainly using ultrasound features and advantages, ultrasound ranging system and the integration with the integration AT89C51 monolithic integrated circuit, AT89C51 monolithic integrated circuit based on the design of a reverse collision avoidance warning systems. The system used software and hardware integrated approach of a modular and multi-use characteristics.
 The paper outlines the development and the basic principles of ultrasound tests on the principles and characteristics of ultrasound sensors. Some of the main parameters for the system were discussed, and introducing ultrasonic ranging system functions basis, the overall composition of the system. Through multiple launch reception circuit design comparison, the best designed programme drawn, and various system design modules principles introduced. On the composition of the system circuit chip introduced and elaborated the principles of their work. Papers introduced system software architecture, through programming to achieve system function. Finally, through the analysis of system error, giving the system improvement programme.
 Key word：monolithic integrated circuit；ultrasonic wave；AT89C51；distance measurement；sensors