Multi-degree-of-freedom target device and method for establishing reference coordinate system

Abstract

The present application relates to the field of image measurement technology, and particularly relates to a multi-degree-of-freedom target device and a method for establishing a reference coordinate system, the target device comprising a base, a multi-degree-of-freedom adjusting mechanism and a reference target, the multi-degree-of-freedom adjusting mechanism being installed on the base, and the reference target being fixed to the multi-degree-of-freedom adjusting mechanism; the reference target is made of hard alloy steel material and has a cubic shape. The multi-degree-of-freedom target device and the method for establishing a reference coordinate system aim to solve the problem that a standard ball cannot satisfy the reference of an image coordinate measurement system.

Description

Technical Field

[0001] This invention relates to the field of image measurement technology, specifically to a multi-degree-of-freedom target device and a method for establishing a reference coordinate system. Background Technology

[0002] In recent years, with the development and progress of science and technology, many industrial fields have increasingly higher requirements for the measurement accuracy and detection efficiency of geometric quantities (such as length and angle), which largely depends on the development of measuring instruments and the advancement of detection technologies. Currently, measurement technology and related disciplines have made significant progress. Image coordinate measurement technology, as a new type of non-contact measurement method, can solve many problems that are difficult or impossible to solve with traditional contact measurement methods and has been widely applied in industrial settings. Image coordinate measurement technology combines non-contact image measurement technology with conventional coordinate measurement technology and applies it to the measurement and positioning of geometric features. It not only possesses the advantages of high efficiency, convenient operation, strong adaptability, and high reliability of non-contact measurement methods, but also features low cost, flexibility, rich information, and strong real-time performance.

[0003] Image coordinate measurement systems use images acquired by industrial image sensors as a means of information acquisition. The image sensor captures images of the object being measured, and then a computer processes and reads these images to obtain data such as the object's dimensions and position. In the application of image coordinate measurement systems, a reference coordinate system is typically required. This reference coordinate system is established based on a fixed point on the system's worktable, allowing for easy and quick reconstruction of the relative positions of various elements even after changing the image sensor or restarting the system.

[0004] For traditional contact coordinate measuring machines (CMMs), the reference coordinate system is typically set on a standard sphere fixed to the worktable. The reference coordinate system is established by measuring this standard sphere and then using its center as the origin. However, for non-contact image coordinate measurement systems, the front-end sensor is an industrial image probe. Unlike conventional contact probes and laser triangulation probes, it has a certain depth of field and outputs a two-dimensional image of the object being measured. Furthermore, during the imaging process of the industrial image probe, a two-dimensional image of the object is formed by projecting a three-dimensional scene onto a two-dimensional image plane, resulting in the loss of spatial depth information. Additionally, it is impossible to position the standard sphere on the object-side focal plane of the industrial image probe. Therefore, standard spheres with three-dimensional spatial characteristics are unsuitable as reference datums for image coordinate measurement systems and cannot be used to establish a reference coordinate system. Since the output of an industrial image probe is a two-dimensional image of the object being measured, and it is sensitive to abrupt changes such as edges and sharp corners, a reference datum needs to be set according to its specific characteristics to determine and establish the reference coordinate system in the image coordinate measurement system.

[0005] In image coordinate measurement systems that use industrial image probes as front-end sensors, a fixed point is needed as a reference datum to establish a reference coordinate system. This ensures that even after changing the industrial image probe or restarting it from a power-off state, the relative positions of various elements can still be recovered based on this reference datum. Image coordinate measurement systems are typically used for two-dimensional planar measurements. However, universal standard spheres with three-dimensional spatial characteristics cannot lie on the object-side focal plane of the industrial image probe and are therefore unsuitable as reference datums for such measurement systems.

[0006] Therefore, the inventors provide a multi-degree-of-freedom target device and a method for establishing a reference coordinate system. Summary of the Invention

[0007] (1) Technical problems to be solved

[0008] This invention provides a multi-degree-of-freedom target device and a method for establishing a reference coordinate system, solving the technical problem that a standard sphere cannot meet the reference reference of an image coordinate measurement system.

[0009] (2) Technical solution

[0010] A first aspect of the present invention provides a multi-degree-of-freedom target device, including a base, a multi-degree-of-freedom adjustment mechanism, and a reference target. The multi-degree-of-freedom adjustment mechanism is mounted on the base, and the reference target is fixed to the multi-degree-of-freedom adjustment mechanism. The reference target is made of hard alloy steel and has a cubic shape.

[0011] Furthermore, each surface of the reference target is a smooth, flat, and uniformly textured matte surface.

[0012] Furthermore, the flatness error of each surface of the reference target is ≤2μm.

[0013] Furthermore, each edge of the reference target is a sharp, continuous, and complete straight edge.

[0014] Furthermore, the multi-degree-of-freedom adjustment mechanism includes a one-dimensional manual angular positioning stage A, a one-dimensional manual angular positioning stage B, a one-dimensional manual rotary table, multiple locking nuts and multiple adjusting handles, and the reference target is installed on the one-dimensional manual rotary table;

[0015] The one-dimensional manual angle positioning stage A and the one-dimensional manual angle positioning stage B are installed in sequence and are respectively used to adjust the rotation angle α of the reference target around the X-axis and the rotation angle β around the Y-axis under the drive of the corresponding adjustment handle, and are locked in position by the corresponding locking nut.

[0016] The one-dimensional manual rotary table is superimposed on the one-dimensional manual angle positioning stage A or the one-dimensional manual angle positioning stage B and is used to adjust the rotation angle γ of the reference target around the Z-axis under the drive of the corresponding adjustment handle, and is locked in position by the corresponding locking nut.

[0017] Furthermore, the multi-degree-of-freedom target device also includes a protective cover, which covers the base, the multi-degree-of-freedom adjustment mechanism, and the reference target.

[0018] Furthermore, the protective cover is a hollow cubic shell made of transparent material.

[0019] Furthermore, a window is provided on the front surface of the protective cover.

[0020] Furthermore, the protective cover is used to fix it on the worktable of the image coordinate measurement system.

[0021] A second aspect of the present invention provides a method for establishing a reference coordinate system based on the above-described multi-degree-of-freedom target device, comprising the following steps:

[0022] Determine the reference coordinate system O S -X S Y S Z S X S Axis, Y S Axis and Z S The positive directions of the axes are the same as the positive directions of the X-axis, Y-axis and Z-axis of the machine coordinate system O-XYZ of the image coordinate measurement system, respectively.

[0023] The X, Y, and Z axes of the image coordinate measurement system are controlled to drive the industrial image probe. When the front surface of the reference target is on the object-side focal plane of the industrial image probe, the grating ruler reading of the X-axis linear motion is determined as the reference coordinate system O. S -X S Y S Z S Origin O S X S0 Coordinate components;

[0024] Lock the X-axis and move the industrial imaging probe along the Y-axis. When the front edge of the reference target is within the field of view of the industrial imaging probe, determine the reference coordinate system O based on the grating ruler reading on the Y-axis linear motion axis and the pixel distance between the image coordinates of the front edge of the absolute position target and the image center coordinates. S -X S Y S Z S Origin O S Y S0 Coordinate components;

[0025] Lock the X-axis and move the industrial imaging probe along the Z-axis. When the edge of the reference target appears in the field of view of the industrial imaging probe, determine the reference coordinate system O based on the grating ruler reading of the Z-axis linear motion and the pixel distance between the image coordinates of the edge of the absolute position target and the image center coordinates. S -X S Y S Z S Origin O S Z S0 Coordinate components;

[0026] According to X S Axis, Y S Axis and Z S The positive direction of the axis and the calculated origin O S 3D coordinates (X) S0 ,Y S0 Z S0 Establish a reference coordinate system O. S -X S Y S Z S .

[0027] (3) Beneficial effects

[0028] In summary, this invention employs a specially designed geometric structure on the reference target in a multi-degree-of-freedom target device. This results in a smooth, flat, uniformly textured matte surface and sharp, continuous, and complete edges, facilitating automatic focusing and accurate edge identification and extraction by industrial image probes. Furthermore, it features simple geometric features, ease of manufacturing, and easily guaranteed geometrical accuracy, making it the optimal measurement object for industrial image probes. This method establishes a reference coordinate system by automatically focusing the reference target and accurately identifying and extracting its edges using an industrial image probe. It fully leverages the advantages of image coordinate measurement systems for measuring planar features and is characterized by its simple principle, ease of use, and ease of automation. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a multi-degree-of-freedom target device provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of a multi-degree-of-freedom adjustment mechanism for a multi-degree-of-freedom target device provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of a reference target for a multi-degree-of-freedom target device provided in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of a protective cover for a multi-degree-of-freedom target device provided in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of a reference coordinate system provided in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram illustrating the process of establishing a reference coordinate system according to an embodiment of the present invention;

[0036] Figure 7 This is a flowchart illustrating a method for establishing a reference coordinate system based on a multi-degree-of-freedom target device according to an embodiment of the present invention.

[0037] Figure 8 This is a schematic diagram of a positive-focus image of the front surface of a reference target acquired according to an embodiment of the present invention;

[0038] Figure 9 This is a pixel distance l provided in an embodiment of the present invention.a A schematic diagram of the calculation;

[0039] Figure 10 This is a pixel distance l provided in an embodiment of the present invention. b A calculation diagram.

[0040] In the picture:

[0041] 1-Base; 11-Mounting hole; 2-Multi-degree-of-freedom adjustment mechanism; 21-One-dimensional manual angle stage A; 22-One-dimensional manual angle stage B; 23-One-dimensional manual rotary stage; 24-Locking nut; 25-Adjusting handle; 3-Reference target; 31-Front surface of reference target; 32-Upper surface of reference target; 33-Side surface of reference target; 34-Upper edge of reference target; 35-Front edge of reference target; 4-Protective cover; 41-Front surface of protective cover; 411-Window; 5-Industrial imaging probe. Detailed Implementation

[0042] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Figure 1This is a schematic diagram of the structure of a multi-degree-of-freedom target device provided in an embodiment of the present invention, as shown below. Figure 1-2 As shown, the device may include a base 1, a multi-degree-of-freedom adjustment mechanism 2, and a reference target 3. The multi-degree-of-freedom adjustment mechanism 2 is mounted on the base 1, and the reference target 3 is fixed to the multi-degree-of-freedom adjustment mechanism 2. The reference target 3 is made of hard alloy steel and is cubic in shape.

[0047] In the above embodiment, the lower part of the base 1 is provided with a plurality of mounting holes 11 for fixing and mounting the base 1 on the worktable of the image coordinate measurement system by screws. The multi-degree-of-freedom adjustment mechanism 2 is mounted on the upper end face of the base 1 by screws. The reference target 3 is mounted and fixed on the multi-degree-of-freedom adjustment mechanism 2 by clamping or bonding.

[0048] The reference target 3 adopts a specially designed geometric structure with a smooth, flat, uniformly textured matte surface and sharp, continuous, and complete edges, which facilitates the automatic focusing and accurate edge identification and extraction of the industrial imaging probe 5. It also features simple geometric features, easy processing, and easy guarantee of shape and position accuracy, making it the best measurement object for the industrial imaging probe 5.

[0049] As an optional implementation, each surface of the reference target 3 is a smooth, flat, and uniformly textured matte surface.

[0050] Specifically, such as Figure 3 As shown, the reference target 3 is made of cemented carbide steel or special alloy steel, and is rectangular in shape. It has good form and position accuracy, dimensional accuracy, and surface quality. All surfaces are smooth, flat, and have a uniform texture with a matte finish, and the flatness error of each surface is no greater than 2μm. Adjacent surfaces are perpendicular to each other, and opposite surfaces are parallel to each other. All edges of the reference target 3 are sharp, continuous, and complete straight edges with good straightness, without chamfers or blunting. The front surface 31 of the reference target faces the industrial image probe 5 in the image coordinate measurement system, the upper surface 32 faces the positive Z-axis, and the side surface 33 faces the positive or negative Y-axis. The upper edge 34 is the edge where the front surface 31 and the upper surface 32 intersect, and the front edge 35 is the edge where the front surface 31 and the side surface 33 intersect.

[0051] After the multi-degree-of-freedom target device is installed on the workbench of the image coordinate measurement system, auxiliary tools such as dial indicators and inductive micrometers are used to adjust the spatial attitude and orientation of the reference target 3 through the multi-degree-of-freedom adjustment mechanism 2. First, the front surface 31 of the reference target is made parallel to the YOZ plane. At this time, the β angle and γ angle of the reference target 3 need to be adjusted by adjusting the adjustment handles 25 of the corresponding one-dimensional manual angle stage B22 and one-dimensional manual rotary stage 23 in the attitude adjustment mechanism 2. Then, the upper surface 32 of the reference target is made parallel to the XOY plane. At this time, the α angle and β angle of the reference target 3 need to be adjusted by adjusting the adjustment handles 25 of the corresponding one-dimensional manual angle stage A21 and one-dimensional manual angle stage B22 in the multi-degree-of-freedom adjustment mechanism 2. The above steps are repeated alternately until the front surface 31 of the reference target is parallel to the YOZ plane and the upper surface 32 of the reference target is parallel to the XOY plane. The locking nuts 24 are then tightened to fix the state of the multi-degree-of-freedom adjustment mechanism 2, thereby fixing and maintaining the state of the reference target 3. At this time, edge 34 of the reference target is in a position parallel to the Y-axis; front edge 35 of the reference target is in a position parallel to the Z-axis.

[0052] As an optional implementation, the multi-degree-of-freedom adjustment mechanism 2 includes a one-dimensional manual angle stage A21, a one-dimensional manual angle stage B22, a one-dimensional manual rotary stage 23, multiple locking nuts 24 and multiple adjustment handles 25, and the reference target 3 is installed on the one-dimensional manual rotary stage 23.

[0053] One-dimensional manual angle positioning stage A21 and one-dimensional manual angle positioning stage B22 are stacked and installed in sequence, and are respectively used to adjust the rotation angle α of the reference target 3 around the X-axis and the rotation angle β around the Y-axis under the drive of the corresponding adjustment handle 25, and are locked in position by the corresponding locking nut 24.

[0054] A one-dimensional manual rotary table 23 is stacked on a one-dimensional manual angle positioning stage A21 or a one-dimensional manual angle positioning stage B22 and is used to adjust the rotation angle γ of the reference target 3 around the Z-axis under the drive of the corresponding adjustment handle 25, and is locked in position by the corresponding locking nut 24.

[0055] Specifically, such as Figure 2 As shown, one-dimensional manual angle positioning stage A21 and one-dimensional manual angle positioning stage B22 are stacked together with their angle adjustment directions perpendicular to each other. They are used to adjust the rotation angle α of the reference target 3 around the X-axis and the rotation angle β around the Y-axis, respectively. The one-dimensional angle position is adjusted within the range of -30° to +30° by adjusting handle 25, and the position is locked by locking nut 24. One-dimensional manual rotary stage 23 is used to adjust the rotation angle γ of the reference target 3 around the Z-axis. The one-dimensional angle position is adjusted within the range of 0° to 360° by adjusting handle 25, and the position is locked by locking nut 24.

[0056] As an optional implementation, the multi-degree-of-freedom target device also includes a protective cover 4, which covers the base 1, the multi-degree-of-freedom adjustment mechanism 2 and the reference target 3.

[0057] Specifically, such as Figure 4 As shown, the multi-degree-of-freedom target device is located inside the protective cover 4 and has no contact with any of the inner surfaces of the protective cover 4. The protective cover 4 is installed and fixed on the worktable of the image coordinate measurement system for dustproofing, anti-collision, and anti-collision protection of the multi-degree-of-freedom target device. The protective cover 4 is a rectangular hollow shell made of transparent acrylic material to facilitate observation and confirmation of the status of the multi-degree-of-freedom target device. The protective cover 4 can cover the multi-degree-of-freedom target device from five directions: above, left, right, front, and rear. The front surface 41 of the protective cover is the surface of the protective cover 4 located between the reference target 3 and the industrial image probe 5. A window 411 is provided on the front surface 41 of the protective cover so that the industrial image probe 5 can observe the front surface 31 of the reference target, the upper edge 34 of the reference target, and the front edge 35 of the reference target.

[0058] like Figure 5-6 As shown, the reference target 3 is used as a reference benchmark in the measurement space of the image coordinate measurement system, thereby establishing the reference coordinate system O of the image coordinate measurement system. S -X S Y S Z S Reference coordinate system O S -X S Y S Z S Let X be a spatial rectangular coordinate system. S Y S and Z S The positive directions of the axes are the same as the positive directions of the X, Y, and Z axes of the machine coordinate system O-XYZ of the image coordinate measurement system, with the origin O. S Located at the intersection of edge 34 on the reference target and front edge 35 on the reference target, its three-dimensional coordinates in the machine coordinate system O-XYZ are (X S0 ,Y S0 Z S0 ).

[0059] Figure 7 This is a flowchart illustrating a method for establishing a reference coordinate system based on the aforementioned multi-degree-of-freedom target device, as provided in an embodiment of the present invention. As shown in the figure, the method may include the following steps:

[0060] S100, Determine the reference coordinate system O S -X S Y S Z S X S Axis, YS Axis and Z S The positive directions of the axes are the same as the positive directions of the X-axis, Y-axis and Z-axis of the machine coordinate system O-XYZ of the image coordinate measurement system, respectively.

[0061] S200 controls the X, Y, and Z axes of the image coordinate measurement system to move the industrial image probe 5. When the front surface 31 of the reference target is on the object-side focal plane of the industrial image probe 5, the grating ruler reading of the X-axis linear motion is determined as the reference coordinate system O. S -X S Y S Z S Origin O S X S0 Coordinate components;

[0062] S300. Lock the X-axis and move the industrial image probe 5 along the Y-axis. When the front edge 35 of the reference target is in the field of view of the industrial image probe 5, determine the reference coordinate system O based on the grating ruler reading of the Y-axis linear motion and the pixel distance between the image coordinates of the front edge 35 of the absolute position target and the image center coordinates. S -X S Y S Z S Origin O S Y S0 Coordinate components;

[0063] S400. Lock the X-axis and move the industrial image probe 5 along the Z-axis. When the edge 34 on the reference target appears in the field of view of the industrial image probe 5, determine the reference coordinate system O based on the grating ruler reading of the Z-axis linear motion and the pixel distance between the image coordinates of the edge 34 on the absolute position target and the image center coordinates. S -X S Y S Z S Origin O S Z S0 Coordinate components;

[0064] S500, based on X S Axis, Y S Axis and Z S The positive direction of the axis and the calculated origin O S 3D coordinates (X) S0 ,Y S0 Z S0 Establish a reference coordinate system O. S -X S Y S Z S .

[0065] In the above embodiment, in step S100, after the image coordinate measurement system returns to zero, the reference coordinate system O is...S -X S Y S Z S X S Y S and Z S The positive directions of the axes are set to be the same for the X, Y, and Z axes of the machine coordinate system O-XYZ of the image coordinate measurement system.

[0066] In step S200, the X, Y, and Z axes of the image coordinate measurement system are controlled to move the industrial image probe 5, causing the front surface 31 of the reference target to enter the field of view of the industrial image probe 5. The focus range and step size in the X-axis direction are set, and the industrial image probe 5 is correctly focused on the front surface 31 of the reference target along the X-axis through an automatic focusing process. At this time, the front surface 31 of the reference target is located on the object-side focal plane of the industrial image probe 5, and the industrial image probe 5 can acquire the clearest positive-focus image of the front surface 31 of the reference target (e.g., ...). Figure 8 (As shown). Record the grating ruler readings of the X, Y, and Z linear motion axes of the image coordinate measurement system at this time as (X1, Y1, Z1), and calculate O. S X S0 The coordinate components are defined by the following formula:

[0067] X S0 =X1 (1).

[0068] In step S300, the X-axis is locked, and the industrial imaging probe 5 moves along the positive or negative Y-axis until the front edge 35 of the reference target appears in the field of view of the industrial imaging probe 5. An image is acquired at this point, and the grating ruler readings of the three linear motion axes X, Y, and Z are recorded as (X2, Y2, Z2)X2 = X1. Then, the image coordinates of the front edge 35 of the reference target in the image are extracted through image processing, such as... Figure 9 As shown, the pixel distance l between it and the image center coordinates is calculated. a (Unit: pixel), then multiplied by the pixel size equivalent K on the object focal plane (unit: mm / pixel) to obtain the pixel distance l. a Converted to physical distance 'a' (unit: mm), that is:

[0069] a=K·l a (2).

[0070] Solve for O S Y S0 The coordinate components are defined by the following formula:

[0071] Y S0 =Y2-a (3).

[0072] In step S400, the X-axis is locked, and the industrial imaging probe 5 moves along the positive Z-axis until the edge 34 on the reference target appears in the field of view of the industrial imaging probe 5. An image is acquired at this point, and the grating ruler readings of the three linear motion axes X, Y, and Z are recorded as (X3, Y3, Z3)X3 = X1. Then, the image coordinates of the edge 34 on the reference target in the image are extracted through image processing, such as... Figure 10 As shown, the pixel distance l between it and the image center coordinates is calculated. b (Unit: pixel), then multiplied by the pixel size equivalent K on the object focal plane (unit: mm / pixel) to obtain the pixel distance l. b Converted to physical distance b (unit: mm), that is:

[0073] b = K·l b (4).

[0074] Solve for O S Z S0 The coordinate components are defined by the following formula:

[0075] Z S0 =Z3-b (5).

[0076] In step S500, the reference coordinate system O is completed. S -X S Y S Z S Once established, the machine coordinate system O-XYZ and the reference coordinate system O can be determined. S -X S Y S Z S The mutual conversion relationship between them is used to transform the measurement data in the machine coordinate system O-XYZ to the reference coordinate system O. S -X S Y S Z S This allows the system to reconstruct the relative positions of each element based on the multi-degree-of-freedom target device, even after the industrial imaging probe has been changed or the device has been restarted after being shut down.

[0077] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0078] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A method for establishing a reference coordinate system for a multi-degree-of-freedom target device, characterized in that, The multi-degree-of-freedom target device includes a base (1), a multi-degree-of-freedom adjustment mechanism (2), and a reference target (3). The multi-degree-of-freedom adjustment mechanism (2) is mounted on the base (1), and the reference target (3) is fixed to the multi-degree-of-freedom adjustment mechanism (2). The reference target (3) is made of hard alloy steel and has a cubic shape. The method includes the following steps: Determine the reference coordinate system O S -X S Y S Z S of X S axis, Y S shaft and Z S The positive directions of the axes are respectively aligned with the machine coordinate system of the image coordinate measurement system. O-XYZ of X axis, Y shaft and Z The positive directions of the axes are the same; Control the image coordinate measurement system X axis, Y shaft and Z The shaft drives the industrial imaging probe (5) to move. When the front surface (31) of the reference target is on the object-side focal plane of the industrial imaging probe (5), it is determined that... X The grating ruler readings of the linear motion axis serve as the reference coordinate system. O S -X S Y S Z S origin O S of X S0 Coordinate components; Lock X axis and along Y The industrial imaging probe (5) is moved along the axial direction. When the front edge (35) of the reference target is in the field of view of the industrial imaging probe (5), according to... Y The grating ruler reading of the linear motion axis, the pixel distance between the image coordinates of the front edge (35) of the reference target and the image center coordinates, determine the reference coordinate system. O S -X S Y S Z S origin O S of Y S0 Coordinate components; Lock X axis and along Z The industrial imaging probe (5) is moved along the axial direction. When the edge (34) on the reference target appears in the field of view of the industrial imaging probe (5), according to... Z The reference coordinate system is determined by the grating ruler reading of the linear motion axis, the pixel distance between the image coordinates of the edge (34) on the reference target and the image center coordinates. O S -X S Y S Z S origin O S of Z S0 Coordinate components; in accordance with X S axis, Y S shaft and Z S The positive direction of the axis and the calculated origin. O S 3D coordinates X S0 , Y S0 , Z S0 Establish a reference coordinate system O S -X S Y S Z S .

2. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 1, characterized in that, Each surface of the reference target (3) is a smooth, flat, and uniformly textured matte surface.

3. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 2, characterized in that, The flatness error of each surface of the reference target (3) is ≤2μm.

4. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to any one of claims 1-3, characterized in that, Each edge of the reference target (3) is a sharp, continuous and complete straight edge.

5. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 1, characterized in that, The multi-degree-of-freedom adjustment mechanism (2) includes a one-dimensional manual angle stage A (21), a one-dimensional manual angle stage B (22), a one-dimensional manual rotary stage (23), multiple locking nuts (24) and multiple adjustment handles (25), and the reference target (3) is installed on the one-dimensional manual rotary stage (23). The one-dimensional manual angle stage A (21) and the one-dimensional manual angle stage B (22) are installed in sequence and are used to adjust the reference target (3) around the corresponding adjustment handle (25) under the action of the corresponding adjustment handle (25). X Rotation angle of the shaft α and around Y Rotation angle of the shaft β And the position is locked by the corresponding locking nut (24); The one-dimensional manual rotary table (23) is superimposed on the one-dimensional manual angle stage A (21) or the one-dimensional manual angle stage B (22) and is used to adjust the reference target (3) around the corresponding adjustment handle (25) under the action of the corresponding adjustment handle (25). Z Rotation angle of the shaft γ And the position is locked by the corresponding locking nut (24).

6. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 1, characterized in that, It also includes a protective cover (4), which covers the base (1), the multi-degree-of-freedom adjustment mechanism (2) and the reference target (3).

7. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 6, characterized in that, The protective cover (4) is a transparent cubic hollow shell.

8. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 6 or 7, characterized in that, The protective cover (4) has a window (411) on its front surface (41).

9. The method for establishing the reference coordinate system of the multi-degree-of-freedom target device according to claim 6, characterized in that, The protective cover (4) is used to fix it on the worktable of the image coordinate measurement system.

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