A Method of Measuring Speed ​​Based on Incremental Photoelectric Encoder

Abstract

The invention particularly relates to a method for measuring a speed based on an incremental photoelectric encoder. The method comprises: S1, asynchronous signal synchronization is carried out on an A-phase signal and a B-phase signal of an incremental photoelectric encoder; S2, the synchronized A-phase and B-phase signals are filtered to generate a signal A1 and a signal B1 after filtering; S3, a 4-bit state register ab_state is set; S4, the quadrature sampling number of the signal A1 and the signal B1 is set to be N; S5, a counter starts counting; when the counter starts counting and the ab_state is equal to 0010, 1011, 1101 or 0100, one is added to the counter successively; and when the counting value of the counter is equal to the N, the counter latches the counting time T and the counter and a timer are reset; and S6, according to the quadrature sampling number N and the counting time T, a speed of forward rotation of the encoder is calculated. According to the method, the counter and the timer carry out processing at a rising edge of one same clock signal, so that the speed measurement accuracy can be enhanced.

Description

technical field [0001] The invention relates to the field of speed measurement of a motion control system, in particular to a method for accurately measuring speed based on an incremental photoelectric encoder. Background technique [0002] In industrial equipment, the incremental photoelectric encoder is a very widely used speed sensor. When working, it can output two orthogonal pulse signals A and B with a phase difference of 90°. When rotating forward, A leads B by 90°; when rotating reversely, B leads A by 90°; through the pulse calculation of A and B signals , the speed information of the mechanical equipment can be obtained, so that it can be precisely controlled. [0003] At present, there are generally two methods for measuring the speed of incremental photoelectric encoders. The first method is to use the quadrature pulse acquisition module of DSP or ARM to first collect the AB pulses of the encoder, and then calculate the number of pulses collected within a certa...

AI Technical Summary

Problems solved by technology

However, this method needs to use the FPGA to decode the AB pulses of the encoder first, and the decoding process itself is relatively cumbersome and takes up FPGA resources; the number of pulses that are not integers at the beginning and end of the sample calculated after decoding is only The encoder is only accurate when it runs at a constant speed, but it is very inaccurate when it is accelerating and decelerating.

Although improved over the first method, there are still significant limitations

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