Differential displacement sensor and measuring method thereof

Abstract

The invention provides a differential displacement sensor and a measuring method thereof. The differential displacement sensor comprises a first laser beam, a first spectroscope set and a processing system, wherein the first spectroscope set comprises a first spectroscope and a second retroreflector, a certain included angle is formed between the first spectroscope and the second retroreflector, alaser beam reflected by the reflecting surface of a triangular-wave retroreflector is emitted in the first spectroscope, one part of the laser beam is sequentially reflected by the first spectroscopeand the second retroreflector to be emitted in one first photoelectric detector, and the other part of the laser beam is transmitted by the first spectroscope to be emitted in the other first photoelectric detector; the processing system is used for calculating a displacement change value of a measured object according to the emitting-position variable quantity of the first laser beam received bythe first photoelectric detectors. According to the differential displacement sensor, by arranging the first spectroscope set, when a machining error exists in the triangular-wave reflecting surface,the comprehensive amplification factors of the whole sensor can be kept coincident, and the measurement accuracy of the sensor is reliably guaranteed.

Description

technical field [0001] The invention relates to the field of measurement technology, in particular to a differential displacement sensor and a measurement method thereof. Background technique [0002] The new principle of displacement measurement based on the optical triangular amplification method is realized on the basis of the optical triangular amplification method, combined with triangular wave optical devices and high-precision PSD (Position Seitive Device, position sensitive (sensitive) detector). The triangular wave optical device subdivides the linear displacement into equal intervals, reduces the processing accuracy and size requirements of optical devices, and at the same time reduces the size requirements of high-precision PSD, and realizes high-precision displacement measurement in a small range. The principle and structure of displacement measurement based on optical triangular magnification method are as follows: figure 1 shown by figure 1 It can be seen tha...

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Problems solved by technology

The magnification is related to the angle of the reflective surface of the triangular wave reflector. To keep the magnification of the sensor consistent, it is required that the angles of each reflective surface of the triangular wave reflector be consistent. However, due to the limitation of the processing technology, it is impossible to guarantee each reflection of the triangular wave reflector. The angles of the surfaces are consistent, and there must be processing errors in the processing of the triangular wave reflective surface itself, resulting in changes in the incident light angle of the PSD during the measurement process, that is, the measurement accuracy of the current displacement sensor cannot be guaranteed.

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