Signal subdividing method and subdividing device for sine-cosine encoder, and motor control device

Abstract

The invention discloses a signal subdividing method for a sine-cosine encoder. The method comprises the following steps of: sampling two paths of output signals, with a phase difference of 90 degrees, of a sine-cosine analogue signal to obtain sampling values A and B of the sine-cosine analogue signal; judging a quadrant with an angle Theta according to the sampling values A and B, specifically determining the angle Theta is in a first quadrant if A and B are both more than 0, determining the angle Theta is in a second quadrant if A is more than 0 and B is less than 0, determining the angle Theta is in a third quadrant if A and B are both less than 0 and determining the angle Theta is in a fourth quadrant if A is less than 0 and B is more than 0; subdividing the sine-cosine analogue signal according to a subdividing factor, setting hysteresis intervals at subdividing points, recording output values corresponding to each subdividing point in the range of 0 to 45 degrees and keeping theoutput value in the hysteresis intervals invariable; and looking up a table and outputting values 0 and 1 according to the quadrant with the angle Theta, a relative difference of absolute values of the sampling values and a tangent.

Description

【Technical field】 [0001] The invention relates to sine-cosine coding, in particular to a signal subdivision method and device for a sine-cosine coder. 【Background technique】 [0002] High-speed and high-precision are the development direction of motor control, and fast acquisition of high-precision current and speed signals is the key means to ensure high-speed and high-precision motor control. The encoder is the most commonly used speed feedback device in motor control. The accuracy of the encoder feedback signal largely determines the speed response and precision of motor control. Commonly used encoders include pulse-type incremental encoders, sin-cosine encoders, and serial communication encoders. [0003] A sine-cosine encoder is an encoder that outputs sine-cosine analog signals. Its physical engraving resolution is generally equivalent to that of a pulse-type incremental encoder, and the output signal is a sine-cosine analog signal. Since the spectrum of the sine-cos...

AI Technical Summary

Problems solved by technology

[0008] The problem of subdivision by amplitude is mainly that as the frequency increases or the distance increases, the amplitude of the analog signal will have a certain attenuation, which will lead to inaccurate subdivision. In order to improve the accuracy of subdivision, the analog signal must be monitored in real time and adjust the value of the subdivision table, which will greatly increase the complexity of the subdivision

The method of subdividing by phase also has glitches at the junction of the subdivision intervals, causing problems such as abnormal subdivision waveforms and distortions. In order to improve the accuracy of subdivision, certain error correction methods must be adopted. Most of these methods are complex and difficult to achieve

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