基于磁阻传感器的车流量检测系统的设计与应用

发布时间：2018-01-07 07:36

本文关键词：基于磁阻传感器的车流量检测系统的设计与应用　出处：《厦门大学》2014年硕士论文　论文类型：学位论文

【摘要】：我国经济发展快速,城市化步伐不断加快,城市汽车数量也在不断攀升,城市交通拥堵十分严重。目前,我国的十字路口红绿信号灯大多采用固定时间的方式控制,虽然有些城市会根据不同时间段或早高峰时期调整红绿信号灯的亮灭时间,但还是无法根据道路实际车况灵活控制红绿信号灯。如何有效灵活控制红绿灯,缓解城市交通拥堵问题已是国内各大城市亟需研究解决的课题之一。如果十字路口红绿信号灯可以根据各方向车道的车流量灵活变化,那么就可以避免出现“白等”情况,可以提高交通系统效率。须设计一个能实时准确体现道路车流量的检测系统,以获取十字路口各方向的车流量信息。目前已有的车流量检测系统大多存在检测性能不够稳定、检测精度偏低、维护不方便等问题。本文设计了一个基于磁阻传感器HMC1022的车流量检测系统。论文首先分析了当前国内外常见的几种车辆检测技术：雷达(微波)、激光、视频和环形感应线圈等四种方式,分别指出其相对优势及存在的不足。其次,结合公式、关系图等详细阐述了磁阻传感器的工作原理。当车辆进入磁阻传感器的检测范围内,由于扰动了原本均匀分布的地磁场,引起磁场变化,磁场变化转化为电压输出。这样就可以得出检测范围内的车流量相关信息。接着单独列一章介绍双轴磁阻传感器HMC1022的外部结构、内部结构及技术参数。了解到惠斯通电桥是HMC1022的核心组成部分,每个电桥有一个敏感轴,分别用来测量与芯片平行和垂直方向的磁场Bx和By。随后全面阐述了本系统的硬件设计方案,硬件部分包含了信号放大、A/D转换、传感器置位／复位、ZigBee无线通信。然后主要介绍了包括数据采集、数据处理、数据通信、RF模块等在内的系统软件设计,以及分析介绍了几种车辆存在检测算法。最后,介绍了不同条件下对磁阻传感器检测节点的测试结果。测试结果表明,由于算法简单正确、硬件电路设计得当,本检测系统对道路车辆具有良好的检测效果。
[Abstract]:China's rapid economic development, the pace of the city continues to accelerate, the number of automobiles in the city is also rising, city traffic congestion is very serious. At present, at the crossroads of red and green lights in our country mostly adopts the fixed time control, although some city according to the bright red and green lights to adjust to different time period or early peak period. But according to the actual condition of road can flexibly control the red and green lights. How to flexibly control the traffic lights, alleviate the city traffic congestion problem has been one of the issues to research the domestic each big city. If the crossroads of red and green lights in accordance with the direction of traffic lane change flexibly, so it can avoid the "white" the situation, can improve the efficiency of traffic system. To design a real-time detection system can accurately reflect the road traffic flow, to obtain the crossroads in all directions At present, most of the existing vehicle flow detection systems have some problems, such as low detection performance, low detection precision and inconvenient maintenance.
This paper introduces the design of a traffic detection system based on magnetoresistive sensor HMC1022. The paper first analyzes several common vehicle detection technology at home and abroad at present: (Wei Bo), laser radar, video and induction loop in four ways, respectively, points out the advantages and disadvantages existing in. Secondly, combined with the formula, the diagram described in detail the working principle of reluctance sensor. When the vehicle enters the detection range of magnetoresistive sensor, because of the disturbance of the original uniform distribution of magnetic field, caused by the change of magnetic field and magnetic field change into voltage output. This may obtain traffic information detection range. Then separate the external structure of a chapter of biaxial reluctance the HMC1022 sensor, the internal structure and technical parameters. To understand the Wheatstone bridge is the core component of HMC1022, each bridge has a sensitive axis, which are used to measure Bx and By. chip and magnetic field parallel and perpendicular to the direction of the subsequent comprehensive exposition of the hardware design of this system, the hardware part includes signal amplification, A/D conversion, sensor set / reset, ZigBee wireless communication. Then mainly introduced including data acquisition, data processing, data communication, RF module, system software design and analysis of several vehicle detection algorithms are introduced. Finally, the test results of magnetoresistive sensor detection node under different conditions.
The test results show that the detection system has good detection effect for road vehicles because of the simple and correct algorithm and the proper design of the hardware circuit.

【学位授予单位】：厦门大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U491.116;TP274

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