High-speed and high-precision magnetic induction absolute value encoder for machine tool spindle and measurement gear of absolute value encoder

Abstract

The invention relates to a high-speed and high-precision magnetic induction absolute value encoder for a machine tool spindle and a measurement gear of the absolute value encoder. The measurement gear comprises an inner-circle major magnetic track and an outer-circle vernier magnetic track which are arranged in a mutual staggered manner, wherein the inner-circle major magnetic track contains Z teeth, and the outer-circle vernier magnetic track contains (Z-1) teeth; the absolute value encoder comprises the measurement gear and a magnetic induction reading head; a magnetic induction element, a signal conditioning circuit and an FPGA interpolation subdivision circuit are arranged in the magnetic induction reading head; Z and (Z-1) sine and cosine orthogonal differential signals are produced by the magnetic induction element through non-contact scanning of the measurement gear, the signals processed by the signal conditioning circuit are subjected to real-time error correction and compensation by the FPGA interpolation subdivision circuit, so that relative positional values of the number of angle lines are generated respectively for Z and (Z-1) tracks, and the absolute value of the current angle is calculated. The high-speed and high-precision magnetic induction absolute value encoder is simple in structure, high in precision, easy to mount and high in anti-shock capacity, positioning precision and repeated positioning precision of the machine tool spindle are improved remarkably, and the overall measurement precision and machining efficiency of a numerical control machine tool are improved.

Description

technical field [0001] The invention relates to an encoder (Encoder), in particular to a high-speed high-precision machine tool spindle, an electric spindle magnetic induction absolute value encoder, which can be widely used in the fields of numerical control machine tools, robots, elevators, and industrial automation. Background technique [0002] An encoder is a sensor used to detect angle, position, speed and acceleration. It is a device that compiles and converts the angular displacement or linear displacement of mechanical rotation into an electrical signal that can be used for communication, transmission and storage. Precision measuring devices that combine machinery and electronics are widely used in many fields such as motors, automobiles, wind power, and robots. In terms of measurement function, encoders can be divided into incremental encoders (also called incremental encoders) and absolute encoders. From the measurement principle, encoders include photoelectric e...

AI Technical Summary

Problems solved by technology

[0014] In order to solve the technical problem of low encoder control accuracy and reliability in the prior art, the present invention provides an absolute value of magnetic induction suitable for high-speed high-precision machine tool spindles Encoder, the encoder applies the working principle of gear induction magnetic force lines, and performs non-contact scanning on the double-track measuring gear with a difference of 1 tooth number to generate a corresponding number of high-reliability sine-cosine quadrature differential signals, using FPGA field programmable logic The device can correct and compensate the DC offset error, amplitude error and quadrature phase error of the sine and cosine signals in real time, and realize the high-precision interpolation and subdivision of the sine and cosine signals, so as to measure the dual track in the encoder system The two trajectories of the gear generate the relative position value of the high-line number angle relative to the power-on moment, and analyze the phase and phase difference between the two trajectories at the same time, because the phase and phase difference within one revolution are fixed and Regular, and then the encoder system can calculate the absolute position of the current angle through the relative position value of the angle line number

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