基于UWB的车身结构应变无线数据采集系统（硬件部分）

学院（系）： 国际学院

专业班级： 车辆gj1503

学生姓名： 许瑶

指导教师： 秦岭

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作者签名：

2019年 5月 30 日

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Abstract

Measuring the strain of the body structure of uavs in off-road environment is the basis to ensure the reliable work of uavs and to optimize the structure of uavs. The goal of this project is to design a body structure strain wireless data acquisition system based on ultra-wideband wireless communication technology UWB, which USES the strain gauge pasted on the body to measure the deformation of the car body in real time, and send it to the top position wirelessly to complete the data storage, display and processing.

The scope of knowledge involved in this topic: theoretical mechanics, material mechanics, computer technology, testing technology, electrical and electronics, software design and development, etc.

The main work contents of this project include:

1. Data collection and program demonstration;

2. Design circuit schematic diagram and PCB diagram, and make measurement nodes;

3. Completed the strain simulation of vehicle structure under different driving conditions, and designed the layout scheme of measuring points.

Key words: strain test; UWB; PCB. The finite element.

Catalogue

Chapter one Introduction 3

1.1 The introduction 3

1.2 UWB technology and its application 3

1.2.1 UWB overview 3

1.2.2 Technical features of UWB 4

1.2.3 main applications of UWB technology 6

1.2.3.1 Military applications 6

1.2.3.2 Civil applications 6

1.2.4 Development strategy and direction of UWB technology 8

1.3 Research content and chapter arrangement of this paper 9

The second chapter is the design of data acquisition and wireless transceiver node 11

2.1 overall framework of the system 11

2.2 strain measurement system based on Wheatstone bridge 11

2.2.1 definition and interpretation of Wheatstone bridge 12

2.2.2 calculation of resistance bridge correlation 13

2.3 Data acquisition system based on high-precision signal conditioning chip 14

2.4 Wireless transceiver system based on UWB 17

2.4.1 DW1000 chip overview 18

2.4.2 Architecture of DW1000 chip 18

2.5 Key chip selection of other chips 22

2.5.1 Microcontroller chip STM32F103C8T6 22

2.5.2 dual output linear voltage regulator chip XC6401 28

2.5.3 level conversion chip MAX3373 29

Chapter three Design of hardware circuit of data acquisition and wireless transceiver node 31

3.1 introduction to circuit design software Altium Designer 31

3.1.1 overview of Altium Designer 31

3.1.2 basic steps and methods of schematic diagram design 32

3.1.3 basic steps and methods of PCB diagram design 34

3.2 basic circuit schematic design 34

3.2.1 MCU and its peripheral circuits 34

3.2.1.1 MCU circuit design 34

3.2.1.2 crystal oscillator (clock) circuit 36

3.2.1.3 reset circuit 36

3.2.1.4 programming interface circuit 37

3.2.1.5 serial port and USB interface circuit 37

3.2.2 signal conditioning circuit 38

3.2.3 level switching circuit 39

3.2.4 wireless transceiver circuit 39

3.2.5 power circuit 40

3.3 circuit schematic diagram 41

3.4 PCB diagram of circuit 43

Chapter four finite element simulation analysis of trussed body 47

4.1 introduction to trussed body 47

4.2 introduction to finite element simulation software ABAQUS 48

4.3 truss body stiffness and modal analysis 50

4.3.1 determine the load under different driving conditions 51

4.3.2 body strength and stiffness simulation and result analysis 53

4.3.3 body mode simulation and result analysis 58

Chapter five work summary and outlook 62

Acknowledgement 65

Reference 66

Chapter one Introduction

1.1 The introduction

In recent years, safety, energy conservation and environmental protection are still the main problems to be solved urgently in the automobile industry.

The static and modal characteristics of the vehicle skeleton are analyzed by finite element method. There are many kinds of stress and strain tests. In general, static stress and strain testing is relatively simple, which can be realized by strain gauge. With the progress of science and technology, the update of plant equipment and the improvement of process methods, the performance of mechanical equipment is constantly improved, with high power density and high integration. Body stress and strain testing is becoming a frequent and challenging task.

There are a variety of methods for strain testing, such as traditional strain testing, electromagnetic testing, and newly born surface acoustic wave. The traditional testing methods gradually fail to meet the requirements and even fail to realize strain testing. Therefore, an important research topic -- wireless strain testing is introduced into the field of strain testing.

Among many wireless strain testing technologies, the wireless strain testing technology based on UWB has gradually become a widely used technology due to its advantages of low cost, low power consumption, convenient use and accurate testing.

1.2 UWB technology and its application

1.2.1 UWB overview

UWB (Ultra Wide band) is a carrier - free communication technology. Data are transmitted by narrow pulses of non-sinusoidal waves in nanoseconds to microseconds. Some call it a revolutionary development in the field of radio and believe it will become the mainstream technology of the future short-range wireless communication. It began with pulsed radio technology, which dates back to the 19th century. Later, Intel and other large companies proposed the MB-OFDM technology scheme that applied UWB. Due to the distinct differences between the two schemes and their strong support, the 802.15.3a working group that formulated UWB standard failed to decide the final standard scheme between the two, so it was left to the market to solve.

With the increasing requirement of short distance wireless communication rate, UWB has attracted more and more attention. Ultra Wide band (UWB) is a carrierless communication technology that USES narrow pulses of non-sinusoidal waves to transmit data, thus occupying a wide spectrum. The main characteristics of UWB technology are high transmission rate, large space capacity, low cost and low power consumption. Data collection is an important part of the visualization and analysis of vehicle deformation. How to establish a general, reliable and convenient data collection system is a meaningful and necessary work.

1.2.2 Technical features of UWB

1) Large system capacity. Shannon formula gives C=Blog2 (1 S/N). It can be seen that the increase of bandwidth makes the increase of channel capacity far greater than the effect brought by the increase of signal power, which is exactly the theoretical mechanism of UWB technology proposed. UWB radio systems have far more subscribers than 3G systems.The structure diagram of UWB positioning system is shown in figure 1-1.