Speed Testing System Of The DC Motor Based On Waveform Analysis

Speed is an extremely important parameters of DC motor, speed measurement is the most important part of DC testing. The traditional motor speed measurement are optical encoder velocimetry, flash velocimetry, tachogenerator velocimetry, etc. However, due to cumbersome to install, and detection of low efficiency, these methods can not meet the motor factory, especially in the factory with mass production of motor. To this end, we study of the speed testing system of DC motor based on waveform analysis in this paper.This paper introduces the research status of the DC motor testing at home and abroad, and the traditional methods of speed testing of DC motor. at the same time, analyse the working principle of DC motor and the relationship between the armature current and current commutation process. Then through analysis of the DC motor's current waveform, we get the relationship between the speed of motor and pulsating frequency of current. After thouse, we gave the detailed description of the system's theoretical method, hardware and software design methods, which is based on analysis of DC motor's current waveform. At last, through the experiment and study, we comfirmed the feasibility of the detection system. Studies include:(1) Build a system to test the DC motor, using computer as a platform, VB as the programming software, and the acquisition equipment is based on the ARM7 chip LPC2134 and USB interface chip CH372. with the Hall sensor for the detection devices. The system is mainly to complete the DC motor speed tests, and has functions: data logging, waveform view, etc.(2) The system's hardware including: signal conditioning circuit, A/D conversion circuit and USB interface circuit. Signal conditioning circuit is consist of signal amplification circuit and filter circuit.(3) The system's software including: target hardware initialization, translantation ofμc / os-ii OS, data acquisition and delivery. Results show that the speed testing system of DC motor based on waveform analysis is easy to realize and extend, at the same time, the interface is intuitive.