基于單片機的超聲波檢測設計畢業(yè)論文

摘   要

隨著社會經(jīng)濟的發(fā)展交通運輸業(yè)日益興旺，汽車的數(shù)量在大副攀升。交通擁擠狀況也日趨嚴重，撞車事件屢屢發(fā)生，造成了不可避免的人身傷亡和經(jīng)濟損失，針對這種情況，設計一種響應快，可靠性高且較為經(jīng)濟的汽車防撞預警系統(tǒng)勢在必行，超聲波測距法是最常見的一種距離測距方法，本文介紹的就是利用超聲波測距法設計的一種倒車防撞報警系統(tǒng)。
論文的內(nèi)容是基于AT89C51單片機倒車防撞系統(tǒng)的設計，主要是利用超聲波的特點和優(yōu)勢，將超聲波測距系統(tǒng)和AT89C51單片機結合于一體，設計出一種基于AT89C51單片機的倒車防撞報警系統(tǒng)。該系統(tǒng)采用軟、硬件結合的方法，具有模塊化和多用化的特點。
論文概述了超聲波檢測的發(fā)展及基本原理，闡述了超聲波傳感器的原理及特性。對于系統(tǒng)的一些主要參數(shù)進行了討論，并且在介紹超聲波測距系統(tǒng)功能的基礎上，提出了系統(tǒng)的總體構成。通過多種發(fā)射接收電路設計方案比較，得出了最佳設計方案，并對系統(tǒng)各個設計單元的原理進行了介紹。對組成各系統(tǒng)電路的芯片進行了介紹，并闡述了它們的工作原理。論文介紹了系統(tǒng)的軟件結構，通過編程來實現(xiàn)系統(tǒng)功能。最后，通過對系統(tǒng)的誤差分析，給出了系統(tǒng)的改進方案。

關鍵字：單片機  超聲波  AT89C51
 

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

目    錄

第1章  緒論 1
1.1  超聲檢測發(fā)展綜述 1
1.2  論文主要內(nèi)容和章節(jié)安排 3
1.3  本設計時間安排 3
第2章  超聲波測距原理 5
2.1  超聲波傳感器介紹 5
2.1.1  超聲波傳感器特性 6
2.2  超聲波檢測概述 7
2.2.1  超聲探傷 8
2.3  超聲測距原理及實現(xiàn)  9
第3章  單片機超聲波測距系統(tǒng)構想 10
3.1  超聲波測距系統(tǒng)總體方案 10
3.2  系統(tǒng)主要參數(shù)考慮 11
3.2.1  傳感器指向角 11
3.2.2  測距儀的工作頻率 12
3.2.3  聲速 12
3.2.4  發(fā)射脈沖寬度 12
3.2.5  測量盲區(qū) 13
第4章  單片機倒車防撞報警系統(tǒng)各組成單元方案設計 14
4.1  發(fā)射接收電路方案設計 14
4.2  顯示報警單元方案設計 22
4.2.1  系統(tǒng)顯示電路設計 22
4.2.2  系統(tǒng)報警電路設計 23
4.3  單片機復位電路 24
4.4  時鐘電路 25
4.5  穩(wěn)壓電源 25
第5章  系統(tǒng)硬件及軟件實現(xiàn) 27
5.1  單片機硬件介紹 27
5.1.1  單片機AT89C51介紹 27
5.1.2  8155芯片介紹 28
5.1.3  74LS244芯片介紹 29
5.1.4  74LS06芯片介紹  30
5.2  運算放大器 31
5.3  LM567芯片介紹 32
5.4  探頭UCM介紹  33
5.5  系統(tǒng)軟件結構  34
5.5.1  主程序  34
5.5.2  顯示子程序和蜂鳴報警子程序  37
第6章  系統(tǒng)誤差分析及改進 39
6.1  誤差產(chǎn)生原因分析 39
6.1.1  溫度對超聲聲速的影響 39
6.1.2  回波檢測對時間測量的影響 40
6.1.3  超聲傳感器所加脈沖電壓對測量范圍和精度的影響 40
6.2  針對誤差產(chǎn)生原因的系統(tǒng)改進方案 40
參考文獻 42
致謝 43