摘 要
随着航天事业的飞速发展，人们对航空安全问题也更加关注。直升机外壳为非金属材料，当空气湿度小的时候，直升机外壳经常聚集大量静电，如果有物体接近时会突然放电，可能会造成测量仪表失灵。直升机在试飞前要进行一系列测试，这时要将直升机外壳接地，但如果接地电阻过大就会影响放电效果，因此要对直升机接地电阻测量。
本设计共有三个量程，每个量程采用不同的测试电流来测电阻，测试电流是通过按键由单片机系统来控制，采用在被测电阻上通过已知恒定电流，取出被测电阻上的压降，经放大器放大适当的倍数使输出相应的直流电压，然后送入A/D转换器，将输出的数字量送入单片机，经单片机处理后送出显示，最后液晶屏上显示的数字就是所测电阻的实际值。本设计克服了搭地电阻测试仪测试时的静电干扰，提高了测量精度，满足航空搭地电阻的测量要求。
关键词：小电阻、四线测量、高精度、静电放电
I
Abstract
With the rapid development， the space industry of aviation security issues of concern. The shell of nonmetal material， and when air is humid when the crust often gather a lot of static， if an object drew nearer suddenly， may cause the measurement instruments. The helicopter flight before taking a series of test， then it will be grounded helicopters to the ground， but if the resistance would affect the discharge effect， so to the resistance is measured.
Designed three quantum， each of the quantum adopt different tests， electrical resistance， electric current pass the test is the key is monolithic integrated circuits to control， the system used to be on resistance by the constant flow and pulled out to be resistance to the pressure of an amplifier， the enlargement of the suitable times the output of the direct voltage， Then into A/D converters and output figures amount to monolithic integrated circuits， it is monolithic integrated circuits after handling them.Finally， the LCD panel displays the number of resistance is measured by the actual value. Designed to overcome the resistance put to test when dosimeters， static and improved the accuracy and to meet with the air resistance of the measure required.
Keywords ： Little resistance Measuring High precision
Electro Static Discharge
II
目录
摘 要 ..................................................................................................................... I Abstract ................................................................................................................ II
第1章 绪论 .......................................................................................................... 1
§1.1 航空搭接电阻测试仪的发展 ....................................................................... 1
1.1.1 国内外航空搭接电阻测试仪的发展情况 ......................................... 1 1.1.2 航空搭接电阻测试仪的发展趋势 ...................................................... 4 §1.2 本设计的主要研究目的和意义 .................................................................. 5 §1.3 本设计的研究目标 ........................................................................................ 5 第2章 基于单片机的搭地电阻测试仪的原理 ................................................... 7
§2.1 航空搭接电阻测试仪的基本构成及元器件选择 ................................... 7 §2.2 航空搭接电阻测试仪元器件工作原理 ..................................................... 7
2.2.1 AT89S52单片机原理 ............................................................................. 7 2.2.2 TLC2543A/D转换器原理 ..................................................................... 19 2.2.3 液晶显示模块原理 ............................................................................... 22
第3章 航空搭接电阻测试仪的硬件设计 ......................................................... 26
§3.1 整体方案设计 ............................................................................................... 26 §3.2 系统硬件设计 ............................................................................................... 27
3.2.1电源模块的设计 .................................................................................... 27 3.2.2 精密恒流源电路 ................................................................................... 29 3.2.3 四线制接入待测电阻电路 ................................................................. 30 3.2.4 放大滤波电路 ....................................................................................... 32 3.2.5 A/D转换与单片机系统 ....................................................................... 33 3.2.6 抗静电电路的设计 ............................................................................... 41
第4章 航空搭接电阻测试仪的软件设计 ......................................................... 43 结论 ...................................................................................................................... 45 致谢 ...................................................................................................................... 46 参考文献 .............................................................................................................. 47 附录 ...................................................................................................................... 49
III
Directory
Abstract.................................................................................................................I Abstract................................................................................................................II
Chapter 1 introduction…………………………………………………………1 §1.1 Aviation lap resistance tester…………………………………….1
1.1.1 Domestic airline lap resistance tester………………………1 1.1.2 Aviation lap resistance tester development trend……… ….4 §1.2 The design of the main research purpose and meaning……………5 §1.3 The design of the study targets……………………………………..5 Chapter 2 Based on SCM and resistance tester by the principle……..7 §2.1 Aviation lap resistance tester is the basic structure and component selection…………………………………..…………………………7 §2.2 Aviation lap resistance tester principle components…………7
2.2.1 AT89S52 SCM principle………………………..…………………..7 2.2.2 TLC2543A/D converters principl……………………………….19 2.2.3 LCD module principle…………………………………………….22 Chapter 3 Aviation lap resistance tester hardware design…………..26 §3.1 The whole scheme design……………………………………………26 §3.2 The system hardware design………………………………………...27
3.2.1 Power supply module design…………………………………….27 3.2.2 Precision constant-current source circuit………………...29 3.2.3 Four wire access to resistance circuit…………………….30 3.2.4 Enlarge filter circuits…………………………………………32 3.2.5 A/D conversion and SCM system………………………………... 33 3.2.6 Antistatic circuit design…………………………………….. 41 Chapter 4 Aviation lap resistance tester software design………….. 43 Conclusion……………………………………………………..…………………45 Thanks………………………………...…………………………………………...46 References……………………………………………………...…………….......47 Appendix…………………………………………………………………………..49
IV
