基于磁感线圈的车流量检测的研究

摘要

为了解决车辆计数问题,将环形线圈作为传感器,铺设在公路行车道上.当车辆通过线圈上面时,由于电感L发生变化,引起振荡电路的频率发生变化；通过锁相环芯片检测频率的变化,使模拟信号转化成数字信号,将锁相环产生的输出信号传入单片机；当单片机检测到锁相环的输出电平由高变到低时,便计数一次,从而完成对车流量的检测.在检测模型的测试中,该系统表现出较快的检测速率和较低的误检率,具有一定的抗干扰能力.%The ring coil taken as a sensor is laid on the highway to count the vehicles passed by. When vehicles run through above the coil, the variation of inductance L causes the frequency of the oscillating circuit changes. The frequency variation is detected by the chip on the phase-locked loop. The analog signal is converted to digital signal. The output signal produced by the phase-locked loop is transmitted to the microcomputer. It counts once when output electrical level changes from high to low, thus the traffic flow detection is completed. In the detection model testing, this system showed a fast detection rate and low false alarm rate. It has a certain anti-jamming capability.