A lateral light alignment device suitable for displacement sensors to measure large circular objects

Abstract

A lateral light alignment device suitable for a displacement sensor to measure a large circular object comprises a fixed platform, a mobile platform and a displacement measurement sensor, the displacement measurement sensors are respectively mounted on the fixed platform and the mobile platform, the device further comprises a collimated light source and an optical differential detection system, the collimated light source is arranged on the fixed platform, the optical differential detection system is arranged on the mobile platform, the differential detection system comprises a focusing lens, a beam splitter, a first light baffle, a second light baffle, a first detector and a second detector, the collimated light source, the focusing lens, the beam splitter, the first detector and the second detector are sequentially connected to form an optical path, a first light baffle is arranged between the refraction direction of the beam splitter and the first detector, and a second light baffle is arranged between the reflection direction of the beam splitter and the second detector. The present invention provides a lateral light alignment device suitable for a displacement sensor to measure a large circular object with high measurement accuracy.

Description

Technical Field

[0001] The invention relates to a transverse light-aiming device. Background Art

[0002] like Figure 1 As shown in the figure, when using optical or other similar displacement sensors to measure the rotation diameter and rotation error of a large circular object, two precision displacement sensors placed in opposite directions can be used. When the circular object being measured rotates around its center, the two displacement sensors record the inner diameter or outer diameter of the object (such as Figure 1 (As shown in the figure) relative to the axial displacement of the sensor, the sum of the displacements of the two sensors reflects the deviation of the measured circular object from its theoretical value. In such a device, how to ensure that the main axes of the two displacement measurement sensors placed in opposite directions completely overlap is the key to achieving accurate measurement. In the prior art, it is impossible to ensure that the main axes of the two displacement measurement sensors placed in opposite directions completely overlap, and the measurement accuracy is low. Summary of the invention

[0003] In order to overcome the disadvantage of low measurement accuracy of the prior art, the present invention provides a lateral light alignment device with high measurement accuracy suitable for use when a displacement sensor measures a large circular object.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A lateral light alignment device suitable for a displacement sensor to measure a large circular object, comprising a fixed platform, a mobile platform and a displacement measurement sensor, wherein the displacement measurement sensors are respectively mounted on the fixed platform and the mobile platform, wherein the device further comprises a collimated light source and an optical differential detection system, wherein the collimated light source is arranged on the fixed platform, and the optical differential detection system is arranged on the mobile platform, wherein the optical differential detection system comprises a focusing lens, a beam splitter, a first light baffle, a second light baffle, a first detector and a second detector, wherein the collimated light source, the focusing lens, the beam splitter, the first detector and the second detector are sequentially connected to form an optical path, wherein a first light baffle is arranged between a refraction direction of the beam splitter and the first detector, and a second light baffle is arranged between a reflection direction of the beam splitter and the second detector.

[0006] Furthermore, the collimated light beam of the collimated light source is directly opposite to the incident direction of the focusing lens, the exit direction of the focusing lens is connected to the incident direction of the beam splitter, the refraction direction of the beam splitter is connected to the first detector optical path through the first light baffle, the reflection direction of the beam splitter is connected to the second detector optical path through the second light baffle, and the first detector and the second detector are both connected to the differential signal module.

[0007] The moving platform is provided with an X regulator and a Y regulator.

[0008] The beneficial effects of the present invention are mainly manifested in: high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the reverse placement of the displacement sensor to measure the rotation diameter and error.

[0010] Figure 2 Figure 3 is a schematic diagram of the peaks displayed by the confocal dispersion sensor.

[0011] Figure 3 is a schematic diagram of the moving platform relative to the collimated beam. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings.

[0013] Reference Figure 3 A lateral light alignment device suitable for a displacement sensor to measure a large circular object, comprising a fixed platform, a mobile platform 1 and displacement measurement sensors 2 and 3, wherein the displacement measurement sensors are respectively installed on the fixed platform and the mobile platform, and the device also comprises a collimated light source and an optical differential detection system, wherein the collimated light source is arranged on the fixed platform, and the optical differential detection system is arranged on the mobile platform 2, wherein the optical differential detection system comprises a focusing lens 9, a beam splitter 7, a first light baffle 6, a second light baffle 5, a first detector 2 and a second detector 4, wherein the collimated light source, the focusing lens 9, the beam splitter 7, the first detector 2 and the second detector 4 are sequentially connected to form an optical path, wherein a first light baffle 6 is arranged between the refraction direction of the beam splitter 7 and the first detector 2, and a second light baffle 5 is arranged between the reflection direction of the beam splitter 7 and the second detector 4.

[0014] Furthermore, the collimated light beam 11 of the collimated light source is directly opposite to the incident direction of the focusing lens 9, the exit direction of the focusing lens 9 is connected to the incident direction of the beam splitter 7, the refraction direction of the beam splitter 7 is connected to the optical path of the first detector 2 through the first light baffle 6, and the reflection direction of the beam splitter 7 is connected to the optical path of the second detector 4 through the second light baffle 5, and the first detector 2 and the second detector 4 are both connected to the differential signal module 3.

[0015] An X adjuster 10 and a Y adjuster 8 are provided on the moving platform.

[0016] The coincidence of the main optical axes of the two displacement sensors is determined by four degrees of freedom, namely the left and right, pitch angle degrees of freedom, and the two lateral degrees of freedom of xy. The present invention describes a method of adjusting the optical axes of the two displacement sensors to be coaxial at close distances, and then moving one of the displacement sensors along the z-axis away from the other sensor in order to measure the inner diameter or outer diameter of a large circular object. How to measure and adjust the lateral offset of one of the displacement sensors relative to its original position. When two such adjustment devices are used in the x and y directions respectively, the positions of the two sensors in the x and y directions can be kept unchanged or within an allowable error range. Taking an optical displacement sensor based on confocal dispersion as an example, Figure 1 The displacement sensor in is replaced with a confocal dispersive optical displacement sensor. When the distance between the two displacement sensors meets the condition of twice the working distance of the sensor plus the positive and negative working range, the light emitted from displacement sensor one can enter displacement sensor two. If the working distance is defined as L and the working range is defined as D, the distance that meets this condition can be described as: 2L±D. For precision displacement sensors, L is generally around 10mm, and D is generally within 2mm; by adjusting a two-dimensional angle adjustment device and a two-dimensional linear adjustment device connected to displacement sensor one or two, the light emitted by one sensor can be optimally imaged in the photosensitive plane of the other sensor. At this time, the sharpest peak can be seen on the sensor, such as Figure 2 shown.

[0017] When the workpiece to be measured is very large, such as the inner or outer diameter of a large cylindrical bearing sleeve (the distance between the two sensors may exceed 2000mm), the distance between the two sensors has far exceeded the maximum distance 2L+D required for light adjustment. In this case, other methods are needed to ensure that the optical axes of the two sensors are still completely consistent or within the allowable error range.

[0018] When the distance between the two displacement sensors exceeds 2L+D, the positions of the two sensors in the x and y directions remain unchanged or within the allowable error range.

[0019] Figure 3is a schematic diagram of the device. In the system, a beam of collimated light is incident on a differential detection system mounted on a mobile platform, and the differential detection system consists of a focusing lens, a beam splitter, a first light baffle, a second light baffle, a first detector, and a second detector. When the center of the collimated light beam coincides with the center of the focusing lens, the first light baffle and the second light baffle just block half of the focused light beam after the beam splitting, and only allow the other half of the light to be projected onto the first detector and the second detector. When the photoelectric effects of the two detectors are consistent and their respective amplification circuits are consistent, the electrical signal strengths output by the two detectors are also consistent. At this time, the differential signal should be equal to zero. The mobile platform is fine-tuned laterally. The positive and negative of the differential signal depends on the direction of movement, and the size depends on the amplitude. When the optical axis consistency of probe 1 and probe 2 is adjusted at a close distance (the distance is between 2L±D), the x and y fine-tuning systems of the mobile platform are adjusted, and the differential signal output by the first detector and the second detector is observed to make the differential signal zero. At this time, the distance between the mobile platform and the fixed platform is increased until the distance between the two probes is just enough to measure the inner diameter or outer diameter of a large circular object, and the differential signal is observed. The lateral fine adjustment on the mobile platform is adjusted until the differential signal is equal to zero. At this time, the optical axes of the two sensors are completely consistent in one direction, or are within the allowable error range. Use two such systems to adjust the two vertical directions (x and y) respectively, and the optical axes of the two probes can be adjusted to completely coincide in the x and y directions or within the allowable error range.

[0020] The core of this device is composed of an optical differential system installed on a fixed platform and a mobile platform. The collimated light source is installed on the fixed platform for measurement. The collimated light beam it emits is consistent with the focusing mirror of a differential system installed on the mobile platform. After the collimated light beam passes through the focusing mirror, it passes through a beam splitter to divide the light into two parts. There is a light blocking plate in the transmission direction and reflection direction of the beam splitter. The edge of the light blocking plate is on the center line of the focusing lens. In this way, if the collimated light beam is consistent with the optical axis of the focusing lens, for the first detector and the second detector, exactly half of the light is blocked. At this time, the light intensity of the two detectors should be equal, and the differential signal is zero. Figure 3 shown.

[0021] Since the focusing lens, beam splitter, light baffle and detector are all mounted on the mobile platform and move with the mobile platform, the mobile platform can move along the z direction relative to the fixed platform. If the mobile platform has any slight movement in the lateral direction (x and y directions) relative to the collimated light beam during the movement, the light blocked by the first light baffle and the second light baffle will no longer be equal, and the differential signal will not be equal to zero. When the mobile platform moves to the right relative to the collimated light beam, the light passing through the first light baffle is less than the light passing through the second light baffle, and the differential signal is positive. The greater the movement, the greater the amplitude.

[0022] Likewise, if the moving stage has a leftward motion relative to the collimated beam, the differential signal will be negative.

[0023] In actual application, two such differential systems can be installed on the mobile platform. In one differential system, the optical axis after the beam splitter is coaxial with the x axis, and the differential system can measure the small displacement of the mobile platform along the x direction; in the other differential system, the optical axis after the beam splitter is coaxial with the y axis, and the differential system can measure the small displacement of the mobile platform along the y direction. As the mobile platform moves along the z direction, due to the straightness error of the linear guide in the z direction and other errors, the mobile platform will produce a small displacement along the x and y directions. Adjust the fine-tuning devices in the x and y directions at any time to make the corresponding differential signals zero.

Claims

1. A lateral light alignment device suitable for a displacement sensor to measure a large circular object, comprising a fixed platform, a mobile platform and a displacement measurement sensor, wherein the fixed platform and the mobile platform are respectively provided with the displacement measurement sensor, characterized in that: The device also includes a collimated light source and an optical differential detection system. The collimated light source is arranged on the fixed platform, and the optical differential detection system is arranged on the movable platform. The optical differential detection system includes a focusing lens, a beam splitter, a first light baffle, a second light baffle, a first detector, and a second detector. The collimated light source, the focusing lens, the beam splitter, the first detector, and the second detector are sequentially connected to form an optical path. A first light baffle is arranged between the refraction direction of the beam splitter and the first detector, and a second light baffle is arranged between the reflection direction of the beam splitter and the second detector. Two optical differential detection systems are installed on the mobile platform. In one differential system, the optical axis after passing through the beam splitter is coaxial with the x axis, which is used to measure the small displacement of the mobile platform along the x direction; in the other differential system, the optical axis after passing through the beam splitter is coaxial with the y axis, which is used to measure the small displacement of the mobile platform along the y direction.

2. A lateral light alignment device suitable for use with a displacement sensor to measure a large circular object as claimed in claim 1, characterized in that: The collimated light beam of the collimated light source is directly opposite to the incident direction of the focusing lens, the exit direction of the focusing lens is connected to the incident direction of the beam splitter, the refraction direction of the beam splitter is connected to the first detector optical path through the first light baffle, the reflection direction of the beam splitter is connected to the second detector optical path through the second light baffle, and the first detector and the second detector are both connected to the differential signal module.

3. A lateral light alignment device suitable for use with a displacement sensor to measure a large circular object as claimed in claim 1 or 2, characterized in that The moving platform is provided with an X regulator and a Y regulator.

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