Time-grating linear displacement sensor

Abstract

The invention discloses a time-grating linear displacement sensor, and the sensor comprises a fixed ruler which consists of a fixed ruler base body and two sensing units, and also comprises a moving ruler which consists of a moving ruler base body and two magnetic conduction units. Each sensing unit comprises an excitation coil and an induction coil, wherein the induction coil starts at a zero point, and two ends of the induction coil are wound along two staggered piecewise functions to form N 90-degree inverted 8-shaped continuous winding tracks, wherein the period of the piecewise functions is W. The winding mode of the induction coils is the same as the winding mode of the excitation coils, and the winding tracks of the induction coils are curves of the winding tracks of the excitation coils after the winding tracks of the excitation coils move by W / 4 towards the right in the measurement direction. The induction coils of the two sensing units are in series connection. Each magnetic conduction unit is formed by the arrangement of a plurality of magnetizers in the measurement direction at equal intervals, and the center distance of two adjacent magnetizers is equal to W / 2. The width b and length L of each magnetizer meet a specific condition, and the starting positions of magnetizers in two magnetic conduction units meet a specific condition. The sensor can prevent the turns of the excitation coils and the distribution condition of all coils from affecting the measurement precision.

Description

technical field [0001] The invention belongs to the technical field of precision measurement sensors, and in particular relates to a time grating linear displacement sensor. Background technique [0002] Precision linear displacement measurement usually uses various types of linear displacement sensors, such as gratings, toothed gratings, capacitive gratings, etc. They mainly improve the measurement resolution through two ways: one is to increase the density of space characterization and reduce the space grating; the other is to increase the electronic subdivision multiple. In recent years, a time-grid linear displacement sensor based on the principle of electromagnetic induction has appeared. Different from the above-mentioned linear displacement sensor, the time-grid linear displacement sensor uses clock pulses as the measurement reference, so its resolution depends on the spatial pole distance of the sensor on the one hand. On the other hand, it also depends on the space...

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Problems solved by technology

However, if it is necessary to further improve its resolution, it can only be achieved by reducing the spatial pole distance or increasing the number of pole pairs of the sensor, which is expensive.

[0003] CN103644834A discloses a time grating linear displacement sensor, which can double the measurement resolution of the time grating linear displacement sensor without increasing the accuracy of the engraved line or the number of sensor poles, but the excitation of the sensing unit The coil is composed of a plurality of forward-wound planar rectangular spiral excitation coils and a plurality of reverse-wound planar rectangular spiral excitation coils arranged in a staggered order along the measurement direction. The induction coil of the sensing unit is different from the excitation coil, and the excitation coil winding is complicated. The structure of the sensor is more complex and not easy to realize; and the measurement accuracy of the sensor will also be affected by the number of turns of the excitation coil and the distribution of each turn coil, and the accuracy is not high

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