超声波车流检测器设计
摘要
本课题设计的是一种悬挂式超声波车流多信息检测器，通过悬挂于路面上方的超声波探头向路面周期性地发射脉冲信号，利用地面回波来判断遮挡物地存在，可用于检测行驶中的机动车车速、车高、车长、大中小分型以及累计车流量、车队长度等信息，并可用于多个车道车流信息的同时检测，综合这些测量参数可获得车流量的必要数据，可为公路建设提供必要的基础依据。
主要技术特点：
1． 采用多探头结构，多个探头之间相互之间有一定距离和交织发射角度，对准同一个被测物体的反射面，可使检测范围内的每一个固定点上反射面的可测方位个数较单探头有所增加，可大大降低回波漏检率；
2． 自动标定超声波探头的架设高度，探头与地面间有无遮挡物的判断以地面回波为基准；
3． 在超声波接收电路中设有信号触发锁定电路和时基控制电路。实现以各探头中最早收到的回波信号为本检测单元的有效信号，有效提高信噪比和检测精度；
4． 在软件中设计了数据抗干扰处理模块(数据滤波)，提高系统的抗干扰能力；
5． 信息融合单元连接多个检测单元(探头)，同时检测多个车道的车流信息：
6． 在软件中设计了模糊识别累计车流量模块，可排除行人或非机动车、摩托车作为遮挡物可能造成的计数干扰，大大提高计数准确度。
目前有关超声波车流检测器的文献较多，但本设计中采用的多探头结构、自动标定超声波探头的架设高度、数据滤波以及多车道测量和检测车队长度等技术在同类设计中未见使用。
The subject of this design is a suspension-type of ultrasonic detector for vehicles' traffic data. In principle, ultrasonic sensors are suspended over a road, which keep emitting pulse signals periodically to nearby and feed back waves to decide existence of any obstacles, thus to detect the speed, height, length, different sizes (heavy, medium and small) of moving vehicles and accumulative flow as well as length of motorcade. Optionally, it can be applied to multitude driving lanes simultaneously for traffic data. By integrating and analyzing these measured data, the necessary figures concerning traffic flow may be obtained, which are fundamental basis guiding road buildings.
This design has distinctive technical features as follows:
1. Applied Multi-sensor construction. Well-calculated distance and crossing angles between sensors aiming at a same target makes it possible to acquire more accurate back waves than single sensor construction. Consequently, error rate is reduced significantly.
2. Able toe stablish the d arum 1 ine automatically r egardless o f t he h eight o f s ensor suspended above the road. The obstacle is detected based on the back wave reflected from road surface.
3. Arranged signal activating lock circuit and time-base control circuit in the sound wave receiving circuit to take the initial signal of back wave as the valid one in the cycle, thus to improve the ratio of signal vs. noise and detective precision.
4. Integrated disturbance-resistant datum module (digital filtering) to strengthen the anti-disturbance capacity of the system.
5. Able to detect the traffic data from multiple lanes simultaneously by connecting several detecting units (sensors) with one central processing unit.
6. Designed fuzzy recognition module in the software to screen out the disturbance
from pedestrians, non-driven vehicles and motorcycles for higher counting accuracy.
Although there are many literatures describing ultrasonic detector for traffic flows, none of the same category has referred the techniques applied in the design herein such as multi-sensor construction, automatically establishing datum line regardless of suspension height, digital filtering and multi-lane detection as well as measuring length of motorcade.
主要技术特点：
1． 采用多探头结构，多个探头之间相互之间有一定距离和交织发射角度，对准同一个被测物体的反射面，可使检测范围内的每一个固定点上反射面的可测方位个数较单探头有所增加，可大大降低回波漏检率；
2． 自动标定超声波探头的架设高度，探头与地面间有无遮挡物的判断以地面回波为基准；
3． 在超声波接收电路中设有信号触发锁定电路和时基控制电路。实现以各探头中最早收到的回波信号为本检测单元的有效信号，有效提高信噪比和检测精度；
4． 在软件中设计了数据抗干扰处理模块(数据滤波)，提高系统的抗干扰能力；
5． 信息融合单元连接多个检测单元(探头)，同时检测多个车道的车流信息：
6． 在软件中设计了模糊识别累计车流量模块，可排除行人或非机动车、摩托车作为遮挡物可能造成的计数干扰，大大提高计数准确度。
目前有关超声波车流检测器的文献较多，但本设计中采用的多探头结构、自动标定超声波探头的架设高度、数据滤波以及多车道测量和检测车队长度等技术在同类设计中未见使用。
The subject of this design is a suspension-type of ultrasonic detector for vehicles' traffic data. In principle, ultrasonic sensors are suspended over a road, which keep emitting pulse signals periodically to nearby and feed back waves to decide existence of any obstacles, thus to detect the speed, height, length, different sizes (heavy, medium and small) of moving vehicles and accumulative flow as well as length of motorcade. Optionally, it can be applied to multitude driving lanes simultaneously for traffic data. By integrating and analyzing these measured data, the necessary figures concerning traffic flow may be obtained, which are fundamental basis guiding road buildings.
This design has distinctive technical features as follows:
1. Applied Multi-sensor construction. Well-calculated distance and crossing angles between sensors aiming at a same target makes it possible to acquire more accurate back waves than single sensor construction. Consequently, error rate is reduced significantly.
2. Able toe stablish the d arum 1 ine automatically r egardless o f t he h eight o f s ensor suspended above the road. The obstacle is detected based on the back wave reflected from road surface.
3. Arranged signal activating lock circuit and time-base control circuit in the sound wave receiving circuit to take the initial signal of back wave as the valid one in the cycle, thus to improve the ratio of signal vs. noise and detective precision.
4. Integrated disturbance-resistant datum module (digital filtering) to strengthen the anti-disturbance capacity of the system.
5. Able to detect the traffic data from multiple lanes simultaneously by connecting several detecting units (sensors) with one central processing unit.
6. Designed fuzzy recognition module in the software to screen out the disturbance
from pedestrians, non-driven vehicles and motorcycles for higher counting accuracy.
Although there are many literatures describing ultrasonic detector for traffic flows, none of the same category has referred the techniques applied in the design herein such as multi-sensor construction, automatically establishing datum line regardless of suspension height, digital filtering and multi-lane detection as well as measuring length of motorcade.
引文
[1] 应崇福。《我们身边的超声世界》，北京，清华大学出版社，2002．1。
[2] 布立茨著，李东林译。《Ultrasonics methods and applications 超声波技术及其应用》，北京，海洋出版社，1992．9。
[3] 段里仁。《道路交通自动控制》，北京，中国人民大学出版社，1999
[4] 孙朝云。《现代道路交通测试技术—原理与应用》，北京，人民交通出版社，2000．9。
[5] 徐吉万，徐东玲。《城市交通的计算机控制和管理》。测绘出版社，1988。
[6] J. krautkramer，李靖译，《Werkstoffprufung mit ultraschall 超声检测技术》，广东，广东科技出版社，1984。
[7] 王煜东。《传感器及应用》，北京，机械工业出版社，2002。
[8] 中国机械工程学会无损检测分会编。《超声波检测》，北京，机械工业出版社，2000。
[9] 倪江华。《交通工程学计算示例》，北京，人民交通出版社，1992。
[10] 孙朝云、李令举、朱道光编著。《汽车制动性能的雷达测试单片机控制系统》。《全国高校自动化专业学术年会论文集》，沈阳，东北大学出版社，1993。
[11] A．P．弗伦奇著，徐绪竺译，《振动与波》。北京，人民教育出版社，1982。
[12] 吴湘奇，《信号、系统与信号处理》。北京，电子工业出版社，1996。
[2] 布立茨著，李东林译。《Ultrasonics methods and applications 超声波技术及其应用》，北京，海洋出版社，1992．9。
[3] 段里仁。《道路交通自动控制》，北京，中国人民大学出版社，1999
[4] 孙朝云。《现代道路交通测试技术—原理与应用》，北京，人民交通出版社，2000．9。
[5] 徐吉万，徐东玲。《城市交通的计算机控制和管理》。测绘出版社，1988。
[6] J. krautkramer，李靖译，《Werkstoffprufung mit ultraschall 超声检测技术》，广东，广东科技出版社，1984。
[7] 王煜东。《传感器及应用》，北京，机械工业出版社，2002。
[8] 中国机械工程学会无损检测分会编。《超声波检测》，北京，机械工业出版社，2000。
[9] 倪江华。《交通工程学计算示例》，北京，人民交通出版社，1992。
[10] 孙朝云、李令举、朱道光编著。《汽车制动性能的雷达测试单片机控制系统》。《全国高校自动化专业学术年会论文集》，沈阳，东北大学出版社，1993。
[11] A．P．弗伦奇著，徐绪竺译，《振动与波》。北京，人民教育出版社，1982。
[12] 吴湘奇，《信号、系统与信号处理》。北京，电子工业出版社，1996。