Precision turntable error measuring device
Patent Information
- Application Number
- CN202210381695.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-04-12
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2042-04-12
AI Technical Summary
分离检测方法对于单一参数的校准精度极高，但是，无法分离耦合误差因素，会导致综合测试误差精度降低
[0028]在本发明提供的技术方案中，两个测量组件分别配合对应的复合靶标，从而，针对待测转台的两个旋转轴进行。对于每个测量组件来说，通过第一波长激光和第二波长激光的位置分别进行读取，能够分别对对应旋转轴的角度和位移进行标定。在本发明提供的技术方案中，能够通过采用不同波长的激光对两个旋转轴的角度和位移分别进行标定，从而，能够在同时对相交度和垂直度进行测量的情况下，解决测量过程中相交度和垂直度误差相互耦合的问题，从而，能够实现在工业生产现场对精密转台的垂直度和相交度误差进行一站式高精度检测，解决垂直度和相交度分离测量时过程误差不可控难题。
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Figure CN116929408B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optoelectronic precision testing technology, and in particular to a precision turntable error measuring device. Background Technology
[0002] Before use, precision turntables typically require calibration and testing of structural parameters such as perpendicularity and intersection. During calibration, perpendicularity and intersection can be measured separately using different calibration devices. While this method offers high accuracy for individual parameters, it fails to isolate coupled error factors, leading to a decrease in overall test accuracy. Furthermore, the need for multiple testing fixtures in this method results in complexity, low efficiency, and the potential introduction of process errors. To avoid these issues, a method using the same testing instrument or fixture for both perpendicularity and intersection can be proposed. Several measurement methods have been developed for this purpose; however, limitations in measurement equipment make high-precision measurement difficult to achieve in industrial production settings. Summary of the Invention
[0003] The precision turntable error measurement device provided by this invention adopts a dual-station reference, which establishes verticality and intersection measurement references by two measurement components. It can realize one-stop high-precision detection of the verticality and intersection errors of the two-dimensional turntable under test, and solve the problem of uncontrollable process error when measuring verticality and intersection separately.
[0004] This invention provides a precision turntable error measuring device, comprising:
[0005] Two composite targets are respectively set on the two rotation axes of the turntable under test; each composite target can perform specular reflection of a first wavelength laser and cornerstone reflector reflection of a second wavelength laser.
[0006] Two measuring components are used to set up corresponding to two composite targets respectively; the measuring components can emit measuring beams with a first wavelength laser and a second wavelength laser to the corresponding composite target, receive the first wavelength laser reflected by the corresponding composite target and calibrate the angle of the corresponding rotation axis, and receive the second wavelength laser reflected by the corresponding composite target and calibrate the displacement of the corresponding rotation axis.
[0007] Optionally, one of the measurement components emits a measurement beam that propagates along a first optical path, and the other laser measurement component emits a measurement beam that propagates along a second optical path; wherein the first optical path and the second optical path are perpendicular to each other and lie in the same plane.
[0008] Optionally, the composite target includes: a corner cone reflector and a quarter glass slide disposed on the incident surface of the corner cone reflector, wherein a dichroic film is disposed between the incident surface of the corner cone reflector and the quarter glass slide.
[0009] Optionally, the measurement component includes:
[0010] The laser emitting module is capable of emitting a measurement beam with a first wavelength laser and a second wavelength laser; wherein the first wavelength laser and the second wavelength laser have the same polarization direction;
[0011] A polarizing beam splitter is positioned in the propagation path of the measurement beam and reflects the measurement beam into the corresponding composite target;
[0012] A dichroic mirror is placed in the propagation path of the first wavelength laser and the second wavelength laser reflected by the corresponding composite target. The first wavelength laser can be reflected by the dichroic mirror, and the second wavelength laser can pass through the dichroic mirror.
[0013] Two position recognition modules receive the first wavelength laser and the second wavelength laser after passing through the dichroic mirror, respectively, and obtain the position of the light spot.
[0014] Optionally, the laser emitting module includes:
[0015] The first laser is used to emit a laser of the first wavelength.
[0016] A second laser is used to emit a second wavelength of laser light;
[0017] A dual-band fiber coupler is used to couple the first wavelength laser and the second wavelength laser into a measurement beam.
[0018] A fiber optic collimator is used to shape the measurement beam before it propagates to the polarizing beam splitter.
[0019] Optionally, one of the two position recognition modules has a focusing lens and an angle detector arranged along the propagation optical path of the first wavelength laser;
[0020] The other of the two position recognition modules has a planar reflector that reflects the second wavelength laser, and a focusing lens and a displacement sensor arranged along the propagation path of the reflected second wavelength laser.
[0021] Optionally, both the angle detector and the displacement sensor are position-sensitive sensors.
[0022] Optionally, the plane mirror is arranged parallel to the dichroic mirror.
[0023] Optionally, in the position recognition module that receives the first wavelength laser, the distance between the position sensitive sensor and the condenser lens is equal to the focal length of the condenser lens;
[0024] In the position recognition module that receives a second wavelength laser, the distance between the position-sensitive sensor and the condenser lens is greater than the focal length of the condenser lens.
[0025] Optionally, it also includes an auxiliary calibration module for splitting the measurement beam into a first calibration beam and a second calibration beam that are mutually perpendicular and coplanar; the auxiliary calibration module includes:
[0026] Two quarter-glass slides are provided with a semi-reflective and semi-transparent film between the two quarter-glass slides. The semi-reflective and semi-transparent film is used to reflect part of the measurement beam to form a first calibration beam and propagate it to one of the measurement components, and to transmit the remaining part of the measurement beam to form a second calibration beam.
[0027] A right-angle reflector is used to redirect the propagation direction of the second calibration beam by 90° before propagating it to the second measurement component.
[0028] In the technical solution provided by this invention, two measuring components are respectively coupled with corresponding composite targets to measure the two rotation axes of the turntable under test. For each measuring component, the positions of the first wavelength laser and the second wavelength laser are read separately, enabling the calibration of the angle and displacement of the corresponding rotation axis. This technical solution allows for the separate calibration of the angle and displacement of the two rotation axes using lasers of different wavelengths. This solves the problem of coupling errors between intersection and perpendicularity during the measurement process, enabling one-stop high-precision detection of the perpendicularity and intersection errors of a precision turntable in industrial production, and resolving the problem of uncontrollable process errors when measuring perpendicularity and intersection separately. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of a precision turntable error measuring device according to an embodiment of the present invention;
[0030] Figure 2 This is a schematic diagram of the composite target of a precision turntable error measuring device according to another embodiment of the present invention;
[0031] Figure 3 This is a schematic diagram of the measuring components of a precision turntable error measuring device according to another embodiment of the present invention;
[0032] Figure 4 This is a schematic diagram of the auxiliary measurement module of a precision turntable error measurement device according to another embodiment of the present invention;
[0033] Figure 5 A schematic diagram of the auxiliary calibration module of the precision turntable error measuring device according to another embodiment of the present invention for calibrating two measuring components. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0035] This invention provides a precision turntable error measuring device, such as... Figure 1 As shown, it includes:
[0036] Two composite targets 200 are respectively mounted on the two rotation axes of the turntable 300 under test. Each composite target 200 can reflect a first wavelength laser beam using a specular surface and a second wavelength laser beam using a cornerstone reflector. In some embodiments, the two composite targets 200 are respectively mounted on the two rotation axes of the turntable 300 under test and can rotate together with the two rotation axes. When calibrating the perpendicularity and intersection of the two rotation axes of the turntable 300 under test, measurement beams containing the first and second wavelength laser beams can be simultaneously emitted into the composite targets 200. When the measurement beams reach the composite targets 200, the first wavelength laser beam is specularly reflected. Since the optical path of the first wavelength laser beam reflected by the specular surface is affected by the mirror angle, the angle of the corresponding rotation axis can be determined by measuring the optical path of the first wavelength laser beam. The second wavelength laser beam is reflected by a cornerstone reflector. The reflecting surface of the cornerstone reflector is inclined, so the optical path of the second wavelength laser beam reflected by the cornerstone reflector is translated synchronously with the movement of the cornerstone reflector, thereby determining the displacement of the corresponding rotation axis.
[0037] Two measurement components 100 are respectively configured to correspond to two composite targets 200. Each measurement component 100 can emit measurement beams having a first wavelength laser and a second wavelength laser towards the corresponding composite target 200, receive the first wavelength laser reflected from the corresponding composite target 200 and calibrate the angle of the corresponding rotation axis, and receive the second wavelength laser reflected from the corresponding composite target 200 and calibrate the displacement of the corresponding rotation axis. In some embodiments, the measurement beams can be formed by coupling the first wavelength laser and the second wavelength laser via a coupler 142, or they can propagate separately along the same path.
[0038] In the technical solution provided by the embodiments of the present invention, two measuring components 100 are respectively coupled with corresponding composite targets 200 to perform measurements on the two rotation axes of the turntable 300 under test. For each measuring component 100, the angle and displacement of the corresponding rotation axis can be calibrated by reading the positions of the first wavelength laser and the second wavelength laser, respectively. In the technical solution provided by the embodiments of the present invention, the angle and displacement of the two rotation axes can be calibrated separately by using lasers of different wavelengths. Therefore, while measuring the intersection and perpendicularity simultaneously, the problem of mutual coupling of intersection and perpendicularity errors during the measurement process can be solved. Thus, one-stop high-precision detection of the perpendicularity and intersection errors of precision turntables can be achieved in industrial production, solving the problem of uncontrollable process errors when measuring perpendicularity and intersection separately.
[0039] As an optional implementation, one measuring component 100 emits a measuring beam that propagates along a first optical path 110, while the other laser measuring component 100 emits a measuring beam that propagates along a second optical path 120; wherein the first optical path 110 and the second optical path 120 are perpendicular and in the same plane. In some embodiments, the measuring beams emitted by the two measuring components 100 may not be limited to a perpendicular state or a coplanar state; however, in this case, it is necessary to know precisely the angle and distance of the measuring beams emitted by the two measuring components 100 so that they can be used as parameters when calculating the perpendicularity and intersection of the two rotation axes. In this embodiment, the measuring beams emitted by the two measuring components 100 are set to be perpendicular and coplanar. During the calculation process, it is not necessary to introduce additional parameters due to positional differences between the two measuring devices. This simplifies the calculation process, reduces the computational load, and avoids errors caused by inaccurate measurement of additional parameters.
[0040] As an optional implementation method, such as Figure 2As shown, the composite target 200 includes a pyramidal reflector 230 and a quarter-glass slide 210 disposed on the incident surface of the pyramidal reflector 230. A dichroic film 220 is disposed between the incident surface of the pyramidal reflector 230 and the quarter-glass slide 210. In some embodiments, the dichroic film 220 is a film layer capable of reflecting a first wavelength laser and transmitting a second wavelength laser. Therefore, the dichroic film 220 can perform specular reflection of the first wavelength laser. The pyramidal reflector 230 can reflect the second wavelength laser transmitted through the dichroic film 220. In some preferred embodiments, when the measuring device emits a measuring beam, a polarizing beam splitter 130 is usually used to reflect the measuring beam so that the measuring beam is incident perpendicular to the incident slide of the pyramidal reflector 230 and the dichroic film 220. In this case, whether it is the first wavelength laser reflected by the dichroic film 220 or the second wavelength laser reflected by the pyramidal reflector 230, its reflected light path is usually very close to the incident light path, or even coincides with the incident light path. At this time, the polarizing beam splitter 130 is positioned on the incident light path. If the first and second wavelength lasers are not processed, the polarizing beam splitter 130 will block the propagation of both lasers. In this embodiment, a quarter-glass plate 210 is provided on the incident surface of the pyramidal reflector 230. Both the first and second wavelength lasers pass through the quarter-glass plate 210 twice. Therefore, the polarization directions of the reflected first and second wavelength lasers differ from the incident polarization directions by 90°, allowing them to pass smoothly through the polarizing beam splitter 130.
[0041] As an optional implementation method, such as Figure 3 As shown, the measurement component 100 includes:
[0042] The laser emitting module is capable of emitting a measurement beam having a first wavelength laser and a second wavelength laser; wherein the first wavelength laser and the second wavelength laser have the same polarization direction; in some embodiments, the first wavelength laser and the second wavelength laser have the same polarization direction, which is beneficial to use the polarizing beam splitter 130 to change the direction of the incident laser without interfering with the reflected laser when the subsequent laser incident and reflected light paths coincide or have very small deviations.
[0043] A polarizing beam splitter 130 is disposed on the propagation path of the measurement beam and reflects the measurement beam into the corresponding composite target 200. In some embodiments, the polarizing beam splitter 130 is a prism capable of transmitting laser light with one polarization direction while reflecting laser light with other polarization directions. In some preferred embodiments, to improve measurement accuracy, the measurement beam is incident perpendicularly onto the incident surface of the composite target 200. In this case, the reflected first-wavelength laser light and the second-wavelength laser light are usually perpendicular to or close to the incident surface of the composite target 200. In this situation, a reflector that reflects the measurement beam is disposed on the incident light path, and it needs to be able to reflect the measurement beam while transmitting the reflected first-wavelength laser light and the second-wavelength laser light. Therefore, in this embodiment, a polarizing beam splitter 130 is used to reflect the measurement beam, and the polarization direction is adjusted during the reflection process so that the reflected first-wavelength laser light and the second-wavelength laser light pass through the polarizing beam splitter 130 after polarization direction adjustment.
[0044] A dichroic mirror 113 is positioned on the propagation paths of the first and second wavelength lasers reflected from the corresponding composite target 200. The first wavelength laser can be reflected by the dichroic mirror 113, while the second wavelength laser can pass through it. In some embodiments, the first and second wavelength lasers are separated by the dichroic mirror 113, allowing them to be identified by different position recognition modules. Since position recognition modules typically identify laser paths through photosensitive sensing, failure to separate the first and second wavelength lasers would result in simultaneous appearance of both wavelengths on the same position recognition module. This would prevent the module from identifying which wavelength is which, making it difficult to determine the angle and displacement of the corresponding rotation axis. In this embodiment, separating the first and second wavelength lasers using the dichroic mirror 113 and employing two separate position recognition modules avoids the influence of stray light on the target, thereby achieving accurate measurement of the target's optical path.
[0045] Two position recognition modules receive the first wavelength laser and the second wavelength laser after passing through the dichroic mirror 113, respectively, and acquire the position of the light spot. In some embodiments, the two position recognition modules identify the position of the light spot of the first wavelength laser and the second wavelength laser, respectively, avoiding the influence of stray light on the recognition accuracy and improving measurement accuracy.
[0046] As an optional implementation, continue as follows Figure 3 As shown, the laser emitting module includes:
[0047] The first laser 143 is used to emit a first wavelength laser;
[0048] The second laser 144 is used to emit a second wavelength laser.
[0049] A dual-band fiber coupler 142 is used to couple the first wavelength laser and the second wavelength laser into a measurement beam.
[0050] The fiber collimator 141 is used to shape the measurement beam and propagate it to the polarizing beam splitter.
[0051] In this embodiment, the first wavelength laser and the second wavelength laser are coupled by a dual-band fiber coupler 142. In conjunction with the aforementioned target and position recognition module, the problem of laser beam deviation and stray light from plane reflection affecting the detector accuracy is solved, thereby improving the accuracy and stability of the measurement.
[0052] As an optional implementation, continue as follows Figure 3 As shown, one of the two position recognition modules has a focusing lens and an angle detector arranged along the propagation path of the first wavelength laser. In some embodiments, the angle detector is typically small in size, while the first wavelength laser typically propagates in a near-parallel light state and has a larger size. If the first wavelength laser moves with the composite target 200, its range of motion will further increase. Therefore, in order to identify the motion of the first wavelength laser, this embodiment uses a focusing lens to focus the first wavelength laser and reduce its spot area.
[0053] The other of the two position recognition modules includes a planar reflector 123 that reflects the second wavelength laser, and a focusing lens and a displacement sensor arranged along the propagation path of the reflected second wavelength laser. In some embodiments, the second wavelength laser, similar to the first wavelength laser, also needs to be focused to achieve accurate displacement recognition. In this embodiment, the second wavelength laser is also reflected by the planar reflector 123 to facilitate the placement of the corresponding position recognition module in a convenient installation location.
[0054] As an optional implementation, both the angle detector and the displacement sensor are position-sensitive sensors.
[0055] As an optional implementation, the plane mirror 123 is arranged parallel to the dichroic mirror 113. In some embodiments, when the plane mirror 123 and the dichroic mirror 113 are arranged parallel, the optical paths of the reflected second-wavelength laser and the second-wavelength laser incident on the dichroic mirror 113 are parallel, and their optical path movements are synchronized. Therefore, adopting the scheme in this embodiment simplifies the calculation process after identifying the position of the light spot.
[0056] As an optional implementation, in the position recognition module receiving the first wavelength laser, the distance between the position-sensitive sensor 111 and the condenser lens 112 is equal to the focal length of the condenser lens 112. In some embodiments, since the optical path of the first wavelength laser is used to identify the angle of the corresponding rotating shaft, the position of the position-sensitive sensor 111 should be set so that the movement of the light spot is sensitive to changes in angle. Since the light spot on the focal plane of the condenser lens 112 is the smallest, setting the position-sensitive sensor 111 on the focal plane can achieve the most accurate recognition. Although angle recognition can also be achieved outside the focal plane, the recognition method outside the focal plane will result in a larger light spot size and insufficient recognition accuracy. Furthermore, when a small vibration or slight movement of the instrument occurs at the detection site, the light spot displacement caused by the vibration or movement of the instrument is easily introduced into the angle recognition, leading to errors. Since the optical path of the first wavelength laser is usually close to parallel to the optical axis of the condenser lens 112, the light spot formed on the focal plane of the condenser lens 112 is usually very close to the focal point of the condenser lens 112. At this time, any translation of the light path incident on the condenser lens 112 will result in a light spot displacement that is negligible.
[0057] In the position recognition module receiving the second wavelength laser, the distance between the position-sensitive sensor 121 and the condenser lens 122 is greater than the focal length of the condenser lens 122. In some embodiments, as mentioned above, the optical path of the second wavelength laser is usually nearly parallel to the optical axis of the condenser lens 122. Therefore, the light spot formed on the focal plane of the condenser lens 122 is usually very close to the focal point of the condenser lens 122. At this time, any translation of the incident optical path leading to the light spot displacement is negligible. If the position-sensitive sensor 121 corresponding to the second wavelength laser is placed on the focal plane of the condenser lens 122, it will be difficult to obtain the displacement information of the optical path before the condenser lens 122. Therefore, in this embodiment, the position-sensitive sensor 121 is placed outside the focal plane. When the distance between the position-sensitive sensor 121 and the condenser lens 122 is less than the focal length of the condenser lens 122, the translation direction of the optical path before incidence and the light spot are the same, and the translation distance ratio is a first ratio. The ratio of the focal length of the condenser lens 122 to the distance between the focal point and the position-sensitive sensor 121 is used as the second ratio, and the first ratio is equal to the second ratio. Similarly, when the distance between the position-sensitive sensor 121 and the condenser lens 122 is greater than the focal length of the condenser lens 122, the direction of translation of the light path before incidence is opposite to that of the light spot, and the translation distance ratio is the first ratio. The ratio of the focal length of the condenser lens 122 to the distance between the focal point and the position-sensitive sensor 121 is used as the second ratio, and the first ratio is equal to the second ratio. In some preferred embodiments, due to the size limitation of the position-sensitive sensor 121, the distance between the position-sensitive sensor 121 and the condenser lens 122 should generally be less than twice the focal length. In this embodiment, the displacement is measured by defocusing the image plane, which solves the problem of the influence of different distances to the composite target 400 on the measurement accuracy.
[0058] As an optional implementation method, such as Figure 4As shown, it also includes an auxiliary calibration module 400, used to divide the measurement beam into a first calibration beam and a second calibration beam that are perpendicular and coplanar. In some embodiments, the auxiliary calibration module 400 forms a first calibration beam and a second calibration beam that are perpendicular and coplanar for position calibration between the two position measurement components 100. Since the first calibration beam and the second calibration beam of the auxiliary calibration module 400 are perpendicular and coplanar, that is, the position between the first calibration beam and the second calibration beam is accurate, the two position measurement components 100 acquire the position and angle of the first calibration beam and the second calibration beam respectively. Based on the values of the position and angle of the first calibration beam and the second calibration beam on the two position measurement components 100, the position and angle relationship between the two position measurement components 100 can be determined. As a preferred embodiment, the positions and angles of the two position measuring components 100 can be adjusted so that the positions and angles of the first calibration beam and the second calibration beam are both zero on the two position measuring components 100. At this time, the two position measuring components 100 can emit perpendicular and coplanar measuring beams, which helps to simplify the calculations in the subsequent measurement process of the turntable 300 under test.
[0059] The auxiliary calibration module 400 includes:
[0060] Two quarter-glass slides 410 and 420 are provided, with a semi-reflective and semi-transparent film 430 disposed between them. The semi-reflective and semi-transparent film 430 is used to reflect a portion of the measurement beam to form a first calibration beam and propagate it to one of the measurement components 100, and to transmit the remaining portion of the measurement beam to form a second calibration beam. In some embodiments, two quarter-glass slides 410 and 420 are provided, such that the reflected first calibration beam passes through the same quarter-glass slides 410 and 420 twice, with its polarization direction changing by 90°, and can pass smoothly through the polarization beam splitter 130; while the transmitted second calibration beam passes through two different quarter-glass slides 410 and 420, with its polarization direction also changing by 90°, and can pass smoothly through the polarization beam splitter 130. It should be noted that in this embodiment, the semi-reflective and semi-transparent film 430 should not be a film layer with beam-splitting characteristics, and both the first calibration beam and the second calibration beam contain both a first wavelength laser and a second wavelength laser simultaneously. This is because the angle and position of two measuring components 100 need to be calibrated simultaneously during the calibration process. If the first calibration beam and the second calibration beam have only one wavelength of laser light, then only one of the angle and position can be calibrated.
[0061] A right-angle reflector 440 is used to deflect the propagation direction of the second calibration beam by 90° before propagating it towards the second measuring component 100. In some embodiments, the right-angle reflector 440 can reflect a beam incident perpendicular to the two quarter-glass slides by 90°, thereby enabling the second calibration beam to form a precise perpendicular and coplanar relationship with the first calibration beam.
[0062] In some embodiments, such as Figure 5 As shown, when testing the turntable 300, the first step is to follow the procedure as follows: Figure 5 The auxiliary calibration module 400 is placed on the support structure of the turntable 300 under test, as shown. One of the measuring components 100 emits a measuring beam to calibrate the positional relationship between the two measuring components 100. After the two measuring components 100 are calibrated, the composite target 200 is set on the two rotation axes of the turntable 300 under test, and the turntable 300 is placed on the support structure. The two measuring devices then begin to emit measuring beams to calibrate the position and angle of the two rotation axes.
[0063] As an exemplary embodiment, the following provides a process for calibrating the turntable 300 under test using the aforementioned precision turntable error measuring device:
[0064] The laser emitted by the first laser 143 and the second laser 144 of one of the measurement components 100 passes through a dual-band fiber coupler 142, a fiber collimator 141, and a polarizing beam splitter 130 before exiting to the auxiliary calibration module 400. The auxiliary calibration module 400 splits the incident laser into two paths: a reflected beam (the first calibration beam) and a transmitted beam (the second calibration beam). The reflected beam passes through the right-angle mirror 440 of the auxiliary calibration module 400 and enters the measurement component 100 that emits the measurement beam. It first passes through the polarizing beam splitter 130, and then... Two wavelength laser beams are separated by dichroic mirror 113. The first wavelength laser beam is transmitted and converged by condenser lens 112 onto position-sensitive sensor PSD111. The second wavelength laser beam is reflected on the surface of dichroic mirror 113, then passes through plane mirror 123 and condenser lens 122, and finally enters position-sensitive sensor PSD121. By adjusting the auxiliary measuring fixture, the light spots of the two position-sensitive sensors are positioned at their respective zero positions, thus calibrating the displacement and angle of measuring component 100 and auxiliary calibration module 400. The transmitted beam passes through auxiliary calibration module 400 into another measuring component 100, passes through polarizing beam splitter 130, and is then separated into two wavelength beams by dichroic mirror 113. The first wavelength laser beam is reflected and transmitted through the polarizing beam splitter 130, then transmitted through the dichroic mirror 113 and converged by the condenser lens 112 to be incident on the position-sensitive sensor 111. The second wavelength laser beam is transmitted through the polarizing beam splitter 130, then reflected on the surface of the dichroic mirror 113, then passed through the plane mirror 123 and the condenser lens 122, and finally incident on the position-sensitive sensor 121. The measurement component 100 is adjusted so that the position of the light spot in the two position-sensitive sensors in the measurement component 100 is zero. At this time, the perpendicularity and intersection of the two measurement components 100 are calibrated.
[0065] After the perpendicularity and intersection of the two measuring components 100 are calibrated, the turntable 300 to be tested, on which the composite target 200 is mounted, is placed on the support structure.
[0066] First, the vertical rotation axis is calibrated using a position measuring component 100 corresponding to the vertical rotation axis. Lasers emitted by the first laser 143 and the second laser 144 pass through a dual-band fiber coupler 142 and a fiber collimator 141 before exiting onto a composite target 200. A dichroic film 220 in the composite target 200 splits the dual-wavelength laser into two beams. The first wavelength laser beam is reflected and passes through a polarizing beam splitter 130, then through a dichroic mirror 113, and finally converges through a condenser lens 112 onto the position-sensitive sensor 111, forming a displacement measurement optical path. The second wavelength laser beam passes through the interior of the composite target 200 and is reflected. The reflected beam passes through the polarizing beam splitter 130, is reflected again on the surface of the dichroic mirror 113, and then passes through a plane mirror 123 and a condenser lens 122 before finally entering the position-sensitive sensor 121, forming an angle measurement optical path. During measurement, the vertical axis is rotated, and the position of the turntable 300 and the composite target 200 are adjusted to minimize the radius of the trajectory circle of the beam incident on the position-sensitive sensor. At this time, the vertical axis rotation axis can be determined by the measurement component 100 in conjunction with the passive composite target 200.
[0067] Then, the rotation axis of the horizontal axis is calibrated using the position measurement component 100 corresponding to the horizontal axis. The lasers emitted by the first laser 143 and the second laser 144 are emitted to the composite target 200 through the dual-band fiber coupler 142, the fiber collimator 141, and the polarizing beam splitter 130. The dichroic film 220 in the composite target 200 splits the dual-wavelength laser into two beams. The first wavelength laser is reflected and passes through the polarizing beam splitter 130, then passes through the dichroic mirror 113 and is converged by the condenser lens 112 to be incident on the position-sensitive sensor 111, forming a displacement measurement optical path. The second wavelength laser beam passes through the interior of the composite target 200 and is reflected. The reflected beam passes through the polarizing beam splitter 130, then is reflected on the surface of the dichroic mirror 113, then passes through the plane mirror 123 and the condenser lens 122, and finally the beam is incident on the position-sensitive sensor 121, forming an angle measurement optical path. During measurement, the vertical axis is fixed and does not rotate, while the horizontal axis is rotated to adjust the composite target 200 so that the radius of the beam trajectory circle on the two position sensitive sensors is minimized. At this time, the measurement component 100, together with the passive composite target 200, can determine the horizontal axis rotation axis.
[0068] The perpendicularity and intersection of the two axes are calculated by determining the displacement and angle relationship between the vertical axis of rotation and the horizontal axis of rotation.
[0069] As can be seen from the above exemplary embodiments, in the technical solution provided by the present invention, by rotating the composite target together with the corresponding rotation axis to find the minimum radius of the beam trajectory circle in the measurement component, the center of the circle with the minimum radius is taken as the rotation axis of the corresponding rotation axis. Based on the radius of the circle, the tilt angle rotation error of the corresponding rotation axis can be calculated simultaneously. Furthermore, the tilt angle rotation error does not affect the measurement of perpendicularity and intersection. Therefore, the measurement accuracy of perpendicularity and intersection is extremely high.
[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A precision turntable error measuring device, characterized in that, include: Two composite targets are respectively set on the two rotation axes of the turntable under test; each composite target can perform specular reflection of a first wavelength laser and cornerstone reflector reflection of a second wavelength laser. Two measuring components are used to respectively correspond to two composite targets; the measuring components can emit measuring beams with a first wavelength laser and a second wavelength laser to the corresponding composite target, receive the first wavelength laser reflected by the corresponding composite target and calibrate the angle of the corresponding rotation axis, and receive the second wavelength laser reflected by the corresponding composite target and calibrate the displacement of the corresponding rotation axis. The composite target includes a corner cone reflector and a quarter glass slide disposed on the incident surface of the corner cone reflector, wherein a dichroic film is disposed between the incident surface of the corner cone reflector and the quarter glass slide. The measurement component includes: The laser emitting module is capable of emitting a measurement beam with a first wavelength laser and a second wavelength laser; wherein the first wavelength laser and the second wavelength laser have the same polarization direction; A polarizing beam splitter is positioned in the propagation path of the measurement beam and reflects the measurement beam into the corresponding composite target; A dichroic mirror is placed in the propagation path of the first wavelength laser and the second wavelength laser reflected by the corresponding composite target. The first wavelength laser can be reflected by the dichroic mirror, and the second wavelength laser can pass through the dichroic mirror. Two position recognition modules receive the first wavelength laser and the second wavelength laser after passing through the dichroic mirror, respectively, and obtain the position of the light spot.
2. The precision turntable error measuring device according to claim 1, characterized in that, One of the measurement components emits a measurement beam that propagates along a first optical path, while the other laser measurement component emits a measurement beam that propagates along a second optical path; wherein the first optical path and the second optical path are perpendicular to each other and lie in the same plane.
3. The precision turntable error measuring device according to claim 1, characterized in that, The laser emitting module includes: The first laser is used to emit a laser of the first wavelength. A second laser is used to emit a second wavelength of laser light; A dual-band fiber coupler is used to couple the first wavelength laser and the second wavelength laser into a measurement beam. A fiber optic collimator is used to shape the measurement beam before it propagates to the polarization beam splitter.
4. The precision turntable error measuring device according to claim 1, characterized in that, One of the two position recognition modules has a focusing lens and an angle detector arranged along the optical path of the first wavelength laser propagation; The other of the two position recognition modules has a planar reflector that reflects the second wavelength laser, and a focusing lens and a displacement sensor arranged along the propagation path of the reflected second wavelength laser.
5. The precision turntable error measuring device according to claim 4, characterized in that, Both the angle detector and the displacement sensor are position-sensitive sensors.
6. The precision turntable error measuring device according to claim 4, characterized in that, The plane mirror is arranged parallel to the dichroic mirror.
7. The precision turntable error measuring device according to claim 5, characterized in that, In the position recognition module that receives the first wavelength laser, the distance between the position-sensitive sensor and the condenser lens is equal to the focal length of the condenser lens; In the position recognition module that receives a second wavelength laser, the distance between the position-sensitive sensor and the condenser lens is greater than the focal length of the condenser lens.
8. The precision turntable error measuring device according to claim 1, characterized in that, It also includes an auxiliary calibration module for splitting the measurement beam into a first calibration beam and a second calibration beam that are mutually perpendicular and coplanar; the auxiliary calibration module includes: Two quarter-glass slides are provided with a semi-reflective and semi-transparent film between the two quarter-glass slides. The semi-reflective and semi-transparent film is used to reflect part of the measurement beam to form a first calibration beam and propagate it to one of the measurement components, and to transmit the remaining part of the measurement beam to form a second calibration beam. A right-angle reflector is used to redirect the propagation direction of the second calibration beam by 90° before propagating it to the second measurement component.