System and method for measuring six-degree-of-freedom kinematic error of rotating shaft

Abstract

The invention discloses a six-degree-of-freedom motion error measurement system and method for a rotating shaft, and the system comprises the rotating shaft, and an angle position error measurement assembly and a tilt motion and radial run-out error measurement assembly which are connected with the rotating shaft, and the tilt motion and radial run-out error measurement assembly comprises a first laser light path. The device further comprises an axial run-out error measurement assembly which is integrated on the first laser light path. The rotating shaft six-degree-of-freedom motion error measurement system is simple in structure and small in occupied space, the method is easy to operate, and accurate measurement of two tilt motion errors, two radial run-out errors, angle positioning errors and axial run-out errors can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of precision measurement technology, and in particular to a system and method for measuring six-degree-of-freedom motion errors of a rotating axis. Background Art

[0002] As the core component of precision mechanical structures, the rotary axis occupies an indispensable position in many instruments and precision manufacturing equipment. For example, the azimuth and pitch rotation axes of instruments such as theodolites and laser trackers, and the rotation axes of manufacturing equipment such as five-axis machining centers and industrial robots, any slight deviation may lead to serious errors in positioning data. Due to the manufacturing errors and external interference, six motion errors (two tilt motion errors, two radial runout errors, angular positioning errors, and axial runout errors) are inevitable during the operation of the rotary axis. The existence of these errors poses a severe challenge to the high accuracy and high precision of precision mechanical structures. Therefore, accurate measurement of rotary axis motion errors is particularly critical.

[0003] At present, there are two types of methods for measuring the motion error of rotating axes: contact measurement and non-contact measurement. Contact measurement usually uses devices such as ballbars and R-tests to detect small changes in the motion of the rotating axis with linear displacement sensors, and combines the error separation model for data processing to obtain various motion errors. This method requires multiple installations of the device, and the error separation model is relatively complex, which is not convenient for error measurement. Non-contact measurement is usually based on optical detection, and the motion error of the rotating axis is reflected on sensors such as photodetectors. The relevant errors are measured based on the principles of laser interference, diffraction and collimation. However, existing methods usually require more optical components, and the integrated measurement system is large in size, which is not convenient for online measurement. Summary of the invention

[0004] The purpose of the present invention is to provide a system and method for measuring the six-degree-of-freedom motion error of a rotating axis, which adopts a simplified structure to realize the measurement of the six-degree-of-freedom motion error of the rotating axis.

[0005] In order to achieve the above-mentioned purpose, the six-degree-of-freedom motion error measurement system of the rotating axis of the present invention includes a rotating axis and an angular position error measurement component and a tilt motion and radial runout error measurement component respectively connected to the rotating axis, the tilt motion and radial runout error measurement component includes a first laser optical path, which also includes an axial runout error measurement component, and the axial runout error measurement component is integrated on the first laser optical path.

[0006] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the tilt motion and radial runout error measurement assembly includes a first laser emission module, a first sensing module, and a first adjustment bracket. The first laser emission module is connected to the end of the rotating shaft through the first adjustment bracket, and the first laser emission module and the first sensing module are arranged in sequence along the first laser optical path.

[0007] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the first laser emission module includes a first laser, a first reflector, a first beam splitter prism, and a first quarter-wave plate arranged along the first laser optical path.

[0008] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the axial runout error measurement assembly includes a second reflector, a first position sensor, and a first beam splitter flat plate. The second reflector and the first position sensor are respectively arranged on both sides of the first beam splitter prism, and the first beam splitter flat plate is arranged between the first quarter-wave plate and the first sensing module.

[0009] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the light beams reflected by the second reflector and the first beam splitter flat plate form an equilateral triangle.

[0010] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the axial runout error measurement assembly further includes a beam splitter flat plate calibration member. The beam splitter flat plate calibration member includes a corner cube prism, a first convex lens, and a second position sensor. The corner cube prism is arranged on one side of the first beam splitter prism along the first laser optical path, and the first convex lens and the second position sensor are arranged on the other side of the first beam splitter prism relative to the corner cube prism.

[0011] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the tilt motion and radial runout error measurement assembly further includes a second adjustment bracket connecting the first sensing module.

[0012] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the first sensing module includes a second beam splitter prism, a third position sensor, a second convex lens, and a fourth position sensor. The transmitted light split by the second beam splitter prism reaches the third position sensor, and the reflected light split by the second beam splitter prism reaches the fourth position sensor through the second convex lens.

[0013] In an embodiment of the above-mentioned six-degree-of-freedom motion error measurement system for a rotating shaft, the angular position error measurement assembly includes a corresponding second laser emission and sensing module and a polyhedron prism. The polyhedron prism is arranged at the end of the rotating shaft.

[0014] In an embodiment of the above-mentioned rotational axis six-degree-of-freedom motion error measurement system, the second laser emission sensing module includes a second laser, a third beam splitting prism, a second quarter-wave plate, a third convex lens, and a fifth position sensor, and the second laser, the third beam splitting prism, the polyhedron prism, the second quarter-wave plate, the third convex lens, and the fifth position sensor are arranged in sequence along the second laser light path.

[0015] The rotational axis six-degree-of-freedom motion error measurement method of the present invention includes the following steps:

[0016] Set up an angular position error measurement component to measure the angular position error;

[0017] Set up an inclination motion and radial runout error measurement component to measure the inclination motion error and the radial runout error;

[0018] Set up an axial runout error measurement component to measure the axial runout error;

[0019] Among them, the axial runout error measurement component is integrally arranged on the first laser light path of the inclination motion and radial runout error measurement component.

[0020] In an embodiment of the above-mentioned rotational axis six-degree-of-freedom motion error measurement method, the first laser emission module of the inclination motion and radial runout error measurement component is connected to the end of the rotational axis through a first adjustment bracket. The first laser emission module is a first laser, a first reflector, a first beam splitting prism, and a first quarter-wave plate arranged along the first laser light path. The first sensing module is arranged along the first laser light path behind the first quarter-wave plate;

[0021] The second reflector and the first position sensor of the axial runout error measurement component are respectively arranged on both sides of the first beam splitting prism, and the first beam splitting flat plate is arranged between the first quarter-wave plate and the first sensing module.

[0022] In an embodiment of the above-mentioned rotational axis six-degree-of-freedom motion error measurement method, the transmitted light split by the first beam splitting prism of the light beam is further reflected by the second reflector and then reaches the first beam splitting flat plate, and then is reflected by the first beam splitting flat plate to reach the first position sensor. The axial runout error is measured by sensing the change in the position of the laser spot.

[0023] In an embodiment of the above-mentioned rotational axis six-degree-of-freedom motion error measurement method, the light beam reflected by the second reflector and the first beam splitting flat plate forms an equilateral triangle.

[0024] In an embodiment of the above-mentioned rotational axis six-degree-of-freedom motion error measurement method, when measuring the axial runout error, it further includes the step of eliminating the tilt angle of the first beam splitting flat plate.

[0025] In an embodiment of the above-described method for measuring the six-degree-of-freedom motion error of a rotating shaft, a corner cube prism is placed directly in front of the first laser emission module. The first convex lens and the second position sensor are arranged on the other side of the first beam splitter prism relative to the corner cube prism. The light beam is split by the first beam splitter prism and transmitted to reach the corner cube prism. The tilt angle and position of the laser beam are adjusted through the first adjustment bracket so that the reflected light beam of the corner cube prism passes through the first convex lens and is focused on the center of the second position sensor, making the reading of the second position sensor zero. Then, the corner cube prism is replaced with the first beam splitter flat plate, and the third adjustment bracket is adjusted to make the reading of the second position sensor zero again. The axial runout error is measured.

[0026] In an embodiment of the above-described method for measuring the six-degree-of-freedom motion error of a rotating shaft, when measuring the axial runout error, it further includes the step of eliminating the influence of the tilt motion error of the rotating shaft on the measurement of the axial runout error.

[0027] In an embodiment of the above-described method for measuring the six-degree-of-freedom motion error of a rotating shaft, the first sensing module is set as the second beam splitter prism, the third position sensor, the second convex lens, and the fourth position sensor. The laser beam emitted by the first laser reaches the first mirror, and the reflected laser beam passes through the first beam splitter prism for splitting. Among them, the reflected light will reach the second beam splitter prism, and then the laser is split again. The transmitted light is split to the third position sensor, and two radial runout errors during the rotation shaft movement are measured by sensing the change in the position of the laser spot. The reflected light is focused on the fourth position sensor through the second convex lens, and two tilt motion errors during the rotation shaft movement are measured by sensing the change in the position of the laser spot.

[0028] In an embodiment of the above-described method for measuring the six-degree-of-freedom motion error of a rotating shaft, two tilt motion errors ε x and ε z during the rotation shaft movement, and the axial runout error Δx satisfy the following relationship:

[0029]

[0030] where, Δy QPD is the change in the position of the light spot on the first position sensor;

[0031] L is the distance between the first beam splitter flat plate and the first position sensor;

[0032] is the nominal rotation angle of the rotating shaft.

[0033] In an embodiment of the above-mentioned method for measuring the six-degree-of-freedom motion error of a rotating shaft, the angular position error measurement component is set as the correspondingly arranged second laser emission and sensing module and the polyhedron prism. The second laser emission and sensing module is set as the second laser, the third beam splitting prism, the second quarter-wave plate, the third convex lens, and the fifth position sensor. The polyhedron prism rotates with the rotating shaft. The laser emitted by the second laser passes through the third beam splitting prism, and its transmitted light reaches the reflecting surface of the polyhedron prism. The reflected light beam passes through the third beam splitting prism again. At this time, the split reflected light passes through the second quarter-wave plate and the third convex lens and reaches the fifth position sensor. The angular position error of the rotation is measured by sensing the change in the position of the laser spot.

[0034] The beneficial effect of the present invention is that the six-degree-of-freedom motion error measurement system of the rotating shaft of the present invention has a simple structure, occupies a small space, and the method is easy to operate, and can accurately measure two tilting motion errors, two radial runout errors, angular positioning errors, and axial runout errors.

[0035] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but it is not a limitation to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the overall structural schematic diagram of the six-degree-of-freedom motion error measurement system of the rotating shaft of the present invention;

[0037] Figure 2 is the measurement optical path structural schematic diagram of the angular position error measurement component of the six-degree-of-freedom motion error measurement system of the rotating shaft of the present invention;

[0038] Figure 3 is the measurement optical path structural schematic diagram of the tilting motion and radial runout error measurement component and the axial runout error measurement component of the six-degree-of-freedom motion error measurement system of the rotating shaft of the present invention;

[0039] Figure 4 is the schematic diagram of the principle of measuring the axial runout error of the rotating shaft;

[0040] Figure 5 is the schematic diagram of the installation tilt error principle of the first beam splitting flat plate;

[0041] Figure 6 and Figure 7 is the schematic diagram of the adjustment of the optical lens group for the axial runout error;

[0042] Figure 8 is the schematic diagram of the error crosstalk analysis principle during the measurement of the axial runout error of the rotating shaft.

[0043] In the figure:

[0044] 1: Rotating shaft

[0045] 2: Angle position error measurement component

[0046] 21: Second laser emission sensing module

[0047] 22: Polyhedron prism

[0048] 211: Second laser

[0049] 212: Third beam splitting prism

[0050] 213: Second quarter wave plate

[0051] 214: Third convex lens

[0052] 215: Fifth position sensor

[0053] 3: Tilt movement and radial runout error measurement component

[0054] 31: First laser emission module

[0055] 311: First laser

[0056] 312: First reflector

[0057] 313: First beam splitting prism

[0058] 314: First quarter wave plate

[0059] 32: First sensing module

[0060] 321: Second beam splitting prism

[0061] 322: Third position sensor

[0062] 323: Second convex lens

[0063] 324: Fourth position sensor

[0064] 33: First adjustment mount

[0065] 34: Second adjustment mount

[0066] 4: Axial runout error measurement component

[0067] 401: Second reflector

[0068] 402: First position sensor

[0069] 403: First beam splitting flat plate

[0070] 404: Corner cube prism

[0071] 405: First convex lens

[0072] 406: Second position sensor

[0073] 407: The third adjustment bracket Detailed implementation manners

[0074] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, so as to further understand the purpose, solution and efficacy of the present invention, but it is not intended to limit the scope of protection of the appended claims of the present invention.

[0075] References to "embodiment", "another embodiment", "this embodiment", etc. in the specification mean that the described embodiment may include specific features, structures or characteristics, but not every embodiment must include these specific features, structures or characteristics. In addition, such expressions do not refer to the same embodiment. Further, when combining specific features, structures or characteristics in an embodiment, it has been shown that combining such features, structures or characteristics into other embodiments is within the knowledge of those skilled in the art, whether or not explicitly described.

[0076] In the specification and subsequent claims, certain terms are used to refer to specific components or parts. Those of ordinary skill in the art should understand that a technical user or manufacturer may use different nouns or terms to refer to the same component or part. The specification and subsequent claims do not use the difference in name as a way to distinguish components or parts, but use the difference in function of components or parts as the criterion for distinction. The terms "comprising" and "including" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the term "connected" herein includes any direct and indirect connection means.

[0077] It should be noted that in the description of the present invention, terms such as "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. For the convenience of clear description, the ordinal terms such as "first", "second", "third", "fourth", etc. mentioned in this article are used to distinguish elements, regions, parts from another identical or similar element, region, part, rather than to limit specific elements, regions, parts.

[0078] Such as Figure 1As shown in the figure, the six-degree-of-freedom motion error measurement system of the rotating shaft of the present invention includes a rotating shaft 1, and an angular position error measurement component 2, a tilt motion and radial runout error measurement component 3, and an axial runout error measurement component 4 that are respectively connected to the rotating shaft 1. The tilt motion and radial runout error measurement component 3 includes a first laser optical path, and the axial runout error measurement component 4 is integrally arranged on the first laser optical path of the tilt motion and radial runout error measurement component 3. Among them, the angular position error measurement component 2 is used to measure the angular position error of the rotating shaft 1, the tilt motion and radial runout error measurement component 3 is used to measure the two tilt motion errors and two radial runout errors of the rotating shaft 1, and the axial runout error measurement component 4 is used to measure the axial runout error of the rotating shaft 1.

[0079] The tilt motion and radial runout error measurement component 3 includes a first laser emission module 31, a first sensing module 32, and a first adjustment bracket 33. The first laser emission module 31 is connected to the end of the rotating shaft 1 through the first adjustment bracket 33. The first laser emission module 31 and the first sensing module 32 are arranged in sequence along the first laser optical path, and the first sensing module 32 is connected to a second adjustment bracket 34. Among them, the second adjustment bracket 34 is, for example, a four-degree-of-freedom (two-dimensional angle and two-dimensional offset) adjustment mechanism.

[0080] As Figure 1 and Figure 3 shown in the figure, the first laser emission module 31 includes a first laser 311, a first reflector 312, a first beam splitter prism 313, and a first quarter-wave plate 314 arranged along the first laser optical path.

[0081] The axial runout error measurement component 4 includes a second reflector 401, a first position sensor 402, and a first beam splitter flat plate 403. The second reflector 401 and the first position sensor 402 are respectively arranged on both sides of the first beam splitter prism 313, and the first beam splitter flat plate 403 is arranged between the first quarter-wave plate 314 and the first sensing module 32.

[0082] As Figure 6 shown in the figure, the axial runout error measurement component 4 further includes a beam splitter flat plate calibration member. The beam splitter flat plate calibration member includes a corner cube prism 404, a first convex lens 405, and a second position sensor 406. The corner cube prism 404 is arranged on one side of the first beam splitter prism 313 along the first laser optical path, and the first convex lens 405 and the second position sensor 406 are arranged on the other side of the first beam splitter prism 313 relative to the corner cube prism 404.

[0083] As Figure 1 and Figure 3 shown in the figure, the first sensing module 32 includes a second beam splitter prism 321, a third position sensor 322, a second convex lens 323, and a fourth position sensor 324.

[0084] As Figure 1 and Figure 2 shown, the angular position error measurement component 2 includes a correspondingly arranged second laser emission and sensing module 21 and a polyhedron prism 22, and the polyhedron prism 22 is arranged at the end of the rotating shaft 1.

[0085] The second laser emission and sensing module 21 includes a second laser 211, a third beam splitting prism 212, a second quarter wave plate 213, a third convex lens 214, and a fifth position sensor 215, and the second laser 211, the third beam splitting prism 212, the polyhedron prism 22, the second quarter wave plate 213, the third convex lens 214, and the fifth position sensor 215 are arranged in sequence along the second laser optical path.

[0086] The present invention is used to simultaneously measure the six-degree-of-freedom motion error of the rotating shaft. As Figure 1 and Figure 2 shown, the system includes a rotating part and a fixed part. The rotating part is installed on the moving rotating shaft 1 and includes a polyhedron prism 22 and a first laser emission module 31 installed on a first adjustment bracket 33. The fixed part is fixed on the base and includes a second laser emission and sensing module 21 for measuring the angular position error and a first sensing module 32 installed on a second adjustment bracket 34.

[0087] The process of measuring the angular position error of the rotating shaft 1 is as follows: Combining Figure 1 and Figure 2 , the polyhedron prism 22 is installed on the rotating shaft 1 and rotates with the rotating shaft 1. The laser emitted by the second laser 211 of the second laser emission and sensing module 21 passes through the third beam splitting prism 212, and its transmitted light P reaches the reflecting surface of the polyhedron prism 22. The reflected light beam passes through the third beam splitting prism 212 again, and at this time, the split reflected light will pass through the second quarter wave plate 213 and the third convex lens 214 (focal length f1) and reach the fifth position sensor 215. By sensing the change Δy1 in the position of the laser spot and combining the following formula, the rotational angular position error ε y is measured.

[0088]

[0089] The process of measuring the tilt motion and radial runout error of the rotating shaft 1 is as follows: Combining Figure 1 and Figure 3, on the first adjustment frame 33, there are carried a first laser 311 of the first laser emission module 31, a first reflecting mirror 312, a first beam splitting prism 313, a first quarter-wave plate 314, and a second reflecting mirror 401 of the axial runout error measurement assembly 4. On the second adjustment frame 34 of the fixed part, there are carried a first beam splitting flat plate 403 of the axial runout error measurement assembly 4, a second beam splitting prism 321 of the first sensing module 32, a third position sensor 322, a second convex lens 323, and a fourth position sensor 324. The laser beam emitted from the first laser 311 reaches the first reflecting mirror 312, and the reflected laser beam passes through the first beam splitting prism 313 for beam splitting. Among them, the reflected light will reach the second beam splitting prism 321, and then the laser is split again. The transmitted light split out reaches the third position sensor 322 to measure two radial runout errors during the movement of the rotating shaft 1, and the reflected light split out will be focused by the second convex lens 323 onto the fourth position sensor 324 to measure two tilt movement errors during the movement of the rotating shaft 1.

[0090] In the present invention, a second reflecting mirror 401 and a first position sensor 402 are added on the first adjustment frame 33 of the rotating part, and a first beam splitting flat plate 403 is added in front of the second beam splitting prism 321 on the second adjustment frame 34 of the fixed part. The transmitted light split out by the first beam splitting prism 313 reaches the second reflecting mirror 402, and the further reflected light beam Q reaches the first beam splitting flat plate 403, and then is reflected by the first beam splitting flat plate 403 and reaches the first position sensor 402 to realize the measurement of the axial runout error. Among them, the light beam reflected by the second reflecting mirror 401 and the first beam splitting flat plate 403 forms an equilateral triangle.

[0091] The measurement principle of the axial runout error is as Figure 4 shown. When there is a runout error δ y at the shaft end, the light spot projected on the first beam splitting flat plate 403 will also have a displacement change, which will further cause the reflected light beam to shift, and the light spot projected on the first position sensor 402 will have a position change △y QPD . Therefore, according to the trigonometric geometric relationship, the relationship between δ y and △y QPD is as shown in the following formula.

[0092]

[0093] For the measurement of the axial runout error, it is necessary to ensure that the vertically incident light is perpendicular to the first beam splitting flat plate 403. As Figure 5 shown, if there is an inclination θ of the beam splitting flat plate, in order to make the light spot projected on the center of the half-reflecting mirror, it will cause the tilt of the end jump measurement optical path. Therefore, the axial runout error relationship will become as shown in the following formula, resulting in inaccurate final measurement results.

[0094]

[0095] Since θ is an unknown quantity, in order to ensure the accuracy of the measurement result of the axial runout error, the tilt angle θ of the first beam-splitting flat plate 403 must be eliminated. The elimination solution is as follows: Figure 6 As shown, a corner cube prism 404 is placed directly in front of the first laser emission module 31. The light transmitted through the first beam-splitting prism 313 reaches the corner cube prism 404. Based on the characteristic that the light reflected by the corner cube prism 404 is parallel to the incident light, the tilt angle and position of the laser beam are adjusted through the first adjustment bracket 33, so that the reflected beam of the corner cube prism 404 passes through the first convex lens 405 and is focused at the center of the second position sensor 406. At this time, the reading of the second position sensor 406 is zero. Then, the first beam-splitting flat plate 403 in front of the first sensing module 32 is used to replace the corner cube prism 404. As shown in Figure 7 the figure, the reading of the second position sensor 406 is also made zero by adjusting the third adjustment bracket 407 behind the first beam-splitting flat plate 403. At this time, it can be considered that the tilt angle θ is eliminated and the incident light is perpendicular to the first beam-splitting flat plate.

[0096] During the measurement of the axial runout error, the tilt motion error of the rotating shaft 1 will also have a crosstalk effect on the measurement result of the axial runout error. As shown in Figure 8 the figure, assume that there is a tilt motion error ε around the X direction of the rotating shaft 1 x . The deviation of this error from the axial runout error is approximately calculated as follows:

[0097] Δδ QPD = L·tanε x

[0098] where L is the distance between the first beam-splitting flat plate 403 and the first position sensor 402.

[0099] Therefore, during the actual measurement process, when the rotation axis is set to 0 degrees, the tilt motion error ε around the X direction of the first sensing module 32 x corresponds to the X direction of the first position sensor 402, and the tilt motion error ε around the Z direction of the first sensing module 32 z corresponds to the Y direction of the first position sensor 402. When the rotation axis rotates counterclockwise, during the rotation process, as the nominal rotation angle changes, the angle value reflected in the Y direction of the first position sensor 402 will also change. The tilt motion errors around the X and Z directions are decomposed in the Y direction of the first position sensor 402 respectively, and then synthesized in the Y direction of the first position sensor 402. Therefore, the actual axial runout error value Δx is:

[0100]

[0101] The six motion errors of the above-mentioned rotating shaft 1 are all sensed by a position sensor. When a laser beam irradiates on the sensing surface of the sensor, a photocurrent is generated. Through amplification and IV conversion by a circuit board, the photocurrent is converted into a voltage. Further, an analog signal is converted into a digital signal by a data acquisition card and transmitted to a computer for data acquisition and analysis, thereby obtaining the measurement values of various errors.

[0102] The embedded method and system for measuring the axial runout error of a rotating shaft proposed by the present invention can perform a six-degree-of-freedom error measurement system, and consider various crosstalk phenomena during the measurement process of the axial runout error, realizing the accurate measurement of the axial runout error.

[0103] Certainly, the present invention may also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present invention.

Claims

1. A six-degree-of-freedom motion error measurement system for a rotating axis, comprising a rotating axis and an angular position error measurement component and a tilt motion and radial runout error measurement component respectively connected to the rotating axis, wherein the tilt motion and radial runout error measurement component comprises a first laser optical path, characterized in that: It also includes an axial runout error measurement component, which is integrated on the first laser optical path.

2. The six-degree-of-freedom motion error measurement system for a rotating axis according to claim 1, characterized in that: The tilt motion and radial runout error measurement component includes a first laser emitting module, a first sensing module and a first adjustment frame. The first laser emitting module is connected to the end of the rotating shaft through the first adjustment frame. The first laser emitting module and the first sensing module are arranged in sequence along the first laser optical path.

3. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 2, characterized in that: The first laser emission module includes a first laser, a first reflector, a first beam splitter prism and a first quarter wave plate arranged along the first laser light path.

4. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 3, characterized in that: The axial runout error measurement assembly includes a second reflector, a first position sensor and a first beam splitter plate. The second reflector and the first position sensor are respectively arranged on both sides of the first beam splitter prism, and the first beam splitter plate is arranged between the first quarter wave plate and the first sensing module.

5. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 4, characterized in that: The light beams reflected by the second reflector and the first beam splitter plate form an equilateral triangle.

6. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 4, characterized in that: The axial runout error measurement assembly also includes a beam splitter plate calibration component, which includes a corner cube prism, a first convex lens and a second position sensor. The corner cube prism is arranged on one side of the first beam splitter prism along the first laser light path, and the first convex lens and the second position sensor are arranged on the other side of the first beam splitter prism relative to the corner cube prism.

7. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 2, characterized in that: The tilt motion and radial runout error measuring assembly further includes a second adjustment bracket connected to the first sensing module.

8. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 2, characterized in that: The first sensing module includes a second beam splitter prism, a third position sensor, a second convex lens and a fourth position sensor. The transmitted light split by the second beam splitter prism reaches the third position sensor, and the reflected light split by the second beam splitter prism reaches the fourth position sensor via the second convex lens.

9. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 1, characterized in that: The angle position error measuring component includes a correspondingly arranged second laser emission sensing module and a polygonal prism, and the polygonal prism is arranged at the end of the rotating shaft.

10. The six-degree-of-freedom motion error measurement system of a rotating axis according to claim 9, characterized in that: The second laser emission sensing module includes a second laser, a third beam splitter prism, a second quarter paddle, a third convex lens and a fifth position sensor, and the second laser, the third beam splitter prism, the polygonal prism, the second quarter paddle, the third convex lens and the fifth position sensor are arranged in sequence along the second laser optical path.

11. A method for measuring six-degree-of-freedom motion errors of a rotating axis, characterized in that: The steps include: Setting an angle position error measurement component to measure the angle position error; Setting a tilt motion and radial runout error measurement component to measure the tilt motion error and radial runout error; An axial runout error measurement component is set to measure the axial runout error; The axial runout error measuring component is integrated in the first laser optical path of the tilt motion and radial runout error measuring component.

12. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 11, characterized in that: A first laser emitting module of the tilt motion and radial runout error measuring assembly is connected to the end of the rotating shaft through a first adjustment frame, the first laser emitting module is a first laser, a first reflector, a first beam splitter prism and a first quarter wave plate arranged along a first laser optical path, and a first sensing module is arranged behind the first quarter wave plate along the first laser optical path; The second reflector and the first position sensor of the axial runout error measuring assembly are respectively arranged on both sides of the first beam splitter prism, and the first beam splitter plate is arranged between the first quarter wave plate and the first sensing module.

13. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 12, characterized in that: The transmitted light separated by the first beam splitter prism is further reflected by the second reflector to reach the first beam splitter plate, and then reflected by the first beam splitter plate to reach the first position sensor, and the axial runout error is measured by sensing the change in the laser spot position.

14. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 13, characterized in that: The light beams reflected by the second reflector and the first beam splitter plate form an equilateral triangle.

15. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 13, characterized in that: When measuring the axial runout error, the method further includes the step of eliminating the tilt angle of the first beam splitter plate.

16. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 15, characterized in that: A corner cube is placed in front of the first laser emitting module, and a first convex lens and a second position sensor are arranged on the other side of the first beam splitter relative to the corner cube. The light beam is split by the first beam splitter and transmitted to the corner cube. The inclination angle and position of the laser beam are adjusted by the first adjustment frame so that the reflected light beam of the corner cube passes through the first convex lens and is focused on the center of the second position sensor so that the reading of the second position sensor is zero. Then, the corner cube is replaced by the first beam splitter plate, and the third adjustment frame is adjusted so that the reading of the second position sensor is zero again. The axial runout error is measured.

17. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 15, characterized in that: When measuring the axial runout error, the method also includes a step of eliminating the influence of the tilt motion error of the rotating axis on the measurement of the axial runout error.

18. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 12, characterized in that: The first sensing module is set to be a second beam splitter prism, a third position sensor, a second convex lens and a fourth position sensor. The laser beam emitted by the first laser reaches the first reflector, and the reflected laser beam passes through the first beam splitter prism for beam splitting, wherein the reflected light will reach the second beam splitter prism, and then the laser will be split again, and the separated transmitted light reaches the third position sensor, and the two radial runout errors in the movement of the rotating axis are measured by sensing the change in the position of the laser spot, and the separated reflected light will be focused to the fourth position sensor through the second convex lens, and the two tilt motion errors in the movement of the rotating axis are measured by sensing the change in the position of the laser spot.

19. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 18, characterized in that: Two tilt motion errors ε during the motion of the rotation axis x and ε z , the axial runout error Δx satisfies the following relationship: Among them, Δy QPD is the position change of the light spot on the first position sensor; L is the distance between the first beam splitter plate and the first position sensor; is the nominal rotation angle of the rotation axis.

20. The method for measuring six-degree-of-freedom motion errors of a rotating axis according to claim 11, characterized in that: An angle position error measurement component is set to a corresponding second laser emission sensing module and a polygonal prism. The second laser emission sensing module is set to a second laser, a third beam splitter prism, a second quarter wave plate, a third convex lens and a fifth position sensor. The polygonal prism rotates along with the rotation axis. The laser emitted by the second laser passes through the third beam splitter prism, and its transmitted light reaches the reflecting surface of the polygonal prism. The reflected light beam passes through the third beam splitter prism again. At this time, the separated reflected light passes through the second quarter wave plate and the third convex lens to reach the fifth position sensor. The rotation angle position error is measured by sensing the change in the laser spot position.

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