The Micro Motor Speed Measuring System Based On Laser-doppler Effect

A method of obtains micromotor's rotational speed using the laser Doppler effectis researched. Realize data gathering using the data acquisition card and the LabVIEWsoftware, finally the procedure processes the data through LabVIEW anddemonstrates the result.According to micromotor's unique feature, the differential motion laser Dopplerpath of rays is built; Optical frequency shift based on the principle of acoustic lightmodulators and optical heterodyne interferometer, etc. to improve the stability andspeed of the signal noise ratio; A reasonable Photoelectric sensor that PIN hybridintegrated optical receiver is chose to convert the optical signals which includes theinformation about micro-motor speed into the Doppler signal; Designed and produceda preliminary signal processing hardware circuit, the circuit including amplification,band-pass filter, phase sensitive detection, low pass filtering part, to pre-process theDoppler signals obtained contain information on the measured motor speed frequencysignal. Analysis the characteristics of the laser Doppler signal, adjusting andoptimizing the experimental system to improve the Doppler signal to noise ratio. Thesignal using data acquisition card for data acquisition, collection procedures carriedout by LabVIEW8.2, then by spectrum analysis and comparison to the filteredDoppler signal, use of LabVIEW procedures for data processing and results, the dataprocessing program includes data acquisition, filtering, counting the algorithm anddisplay results.Through the micro-motor and motor DTG speed measurement experiment, theexperimental results show that this system can measure the speed of micro motors.