Papers by Keyword: Speed Measuring

Abstract: In order to realize the warning at the fixed time for the trains closed to the railway crossing, a design method for speed measuring of railway crossing was proposed based on track circuit. Two 25-meter track circuits were set at far end of railway crossing, when the trains closed to the railway crossing, the two track circuits was operation in turns. The single-chip circuit was used to calculated the time interval of the two track circuits operation, then the speed of trains was known and sent to the crossing control center and we can determine the reasonable time about the crossing closed. Experimental results show that speed accuracy can be achieved 0.1m/S that can meet the system requirements.

Abstract: Based on the labVIEW platform, speed measuring system is constructed by using data acquisition card for photoelectric coder. Both method M and T are showed by labVIEW. At the same time, this paper introduces the construction and principle and the implementation of the program of the whole system. The whole system is expanded around data acquisition card, motor driver uses data acquisition card to transmit pulse to drive motor. At the same time, the signal of photoelectric coder converted by transition circuit is received by the different ports of data acquisition card. In terms of hardware, data acquisition card is the core of the system; In terms of software, motor driver, the program of method M and method T are main modules of whole program. The program adopts modular thought to design, and system uses a master module to coordinate the various modules to achieve the desired effect.Keywords: labVIEW; photoelectric coder; speed measuring; data acquisition card.

Abstract: This paper investigates the problem of frequency doubling with speed measuring radars. The main reason for it is that the gain of the reflected wave receiver cannot cope with all the possible waves reflected by cars of different distances away from the radar. Strong signals will saturate the receiver and generate harmonics which interferes with the speed measuring. Based on this, a harmonic detection and frequency doubling suppression method is developed in this paper and the effectiveness of the method is verified by experimental results.

Abstract: To reduce the accident, a radar speed measuring and monitoring system based on DSP chip-TMS320F2812 is designed in this paper. Continuous wave radar is used to receive echoes which are reflected from moving vehicles and frequency spectrum is analyzed with FFT. And then, velocity is calculated with the Doppler effect formula. Finally, the velocity is uploaded to the monitoring center by RS-232 UART. An experimental platform is produced and do the experiment by this method, simulation and experimental data show that it is an effective way to improve the speed-measuring accuracy and reduce accident rates.