A method for measuring the coordinates of the rotation center of a visual coordinate measuring device

Abstract

The present invention relates to the technical field of machine vision measurement and coordinate measurement, and in particular to a method for measuring the coordinates of the rotation center of a visual coordinate measuring device, comprising the steps of: adjusting the spatial posture of an absolute position target, calibrating the relative position relationship between the absolute position target and a dual-axis turntable, and determining a reference coordinate system. S ‑X S Y S Z S Origin O S X S0 Coordinate components, determine the reference coordinate system O S ‑X S Y S Z S Origin O S Y S0 Coordinate components, determine the reference coordinate system O S ‑X S Y S Z S Origin O S Z S0 Coordinate components, solve the rotation axis position O of the dual-axis turntable B and O C The purpose of the method for measuring the rotation center coordinates of a vision coordinate measuring device is to solve the problem that the position of the dual-axis rotary table of the vision coordinate measuring device is affected by the startup and zero return states of the three-coordinate measuring machine, resulting in reduced performance.

Description

Technical Field

[0001] The present invention relates to the technical field of machine vision measurement and coordinate measurement, and in particular to a method for measuring the coordinates of a rotation center of a visual coordinate measuring device. Background Art

[0002] Currently, measurement technology and related disciplines have made significant progress. Machine vision measurement, as a non-contact measurement technique, can solve a variety of problems that are difficult or impossible to solve with traditional measurement methods and has been widely used in industrial fields. Derived from computer vision technology, machine vision measurement is a new measurement technology based on industrial cameras, lenses, lighting, and image processing. It not only offers the advantages of non-contact measurement methods, such as high efficiency, ease of operation, strong adaptability, and high reliability, but also features low cost, flexibility, rich information, and strong real-time performance. Furthermore, coordinate measuring machines (CMMs) offer advantages such as a large range of motion, precise positioning, good repeatability, and strong versatility. They can serve as mobile carriers for image acquisition devices such as industrial cameras. By moving three linear axes, the camera's motion trajectory is tracked, enabling the acquisition of measurement data at various locations. However, an industrial camera in a single position can only capture a portion of the measurement data. To obtain complete measurement data, it is sometimes necessary to add two rotary axes to the three linear axes, creating a dual-axis rotary table. This creates a five-axis vision coordinate measurement system with five degrees of freedom. The dual-axis turntable is used to measure the object in different directions, so as to obtain complete measurement data and improve measurement efficiency.

[0003] In order for this new five-axis vision coordinate measurement system to truly possess the five-axis vision coordinate measurement function, it is necessary to calibrate the positions or three-dimensional coordinates of the axes of the two rotary axes in the machine coordinate system before use. This allows the establishment of a rotary coordinate system to convert the measurement data obtained at different angular positions into a unified spatial coordinate system, thus achieving multi-axis measurement. However, for the three-dimensional coordinate measuring machine in the system, each linear axis is usually equipped with an incremental grating scale or a relative grating scale. This grating scale has no absolute zero position and must be set to zero by triggering a travel switch. Therefore, the reading of the reading head at any position is not fixed, but is related to the set zero point position or preset point reading. The reading at any position is displayed by counting the increase or decrease pulses from that point (zero point or preset point). Most three-dimensional coordinate measuring machine products use incremental grating scales, and most three-dimensional coordinate measuring machine products must return to zero after powering on to set the grating zero point (machine coordinate system zero point).

[0004] During the zeroing process after the CMM is powered on, its X, Y, and Z axes all move in a defined order and direction toward the designated end point of their travel. Upon reaching the end point, they search back. Upon finding the first zero mark on the grating scale, the grating counter is reset to zero. This point represents the machine coordinate system zero point in this zeroing state. Therefore, the zero point of the CMM's machine coordinate system is affected by the zeroing process and the travel switches, resulting in zero point deviation and drift. This causes the zeroing state to vary after each power-up. This results in the rotation center position of the dual-axis rotary table, determined after a power-up and zeroing, being unsuitable for measurement tasks after the next power-up and zeroing. Only after the next power-up and zeroing can the new relative position between the dual-axis rotary table and the CMM's machine coordinate system zero point be determined through coordinate correction or recalibration. This can then be used in subsequent measurement processes to obtain accurate multi-view measurement data. This makes the operation and use of five-axis vision coordinate measurement systems extremely cumbersome and inconvenient, significantly reducing their effectiveness.

[0005] Therefore, the inventor provides a method for measuring the coordinates of the rotation center of a visual coordinate measuring device. Summary of the Invention

[0006] (1) Technical problems to be solved

[0007] An embodiment of the present invention provides a method for measuring the center coordinates of a visual coordinate measuring device, which solves the technical problem that the position of a two-axis turntable of a five-axis visual coordinate measuring system is affected by the power-on and zero return states of a three-coordinate measuring machine, resulting in reduced efficiency.

[0008] (2) Technical solution

[0009] The present invention provides a method for measuring the coordinates of the center of rotation of a visual coordinate measuring device, wherein the visual coordinate measuring device includes a five-axis visual coordinate measuring device and a target device and a target device protective cover installed on the five-axis visual coordinate measuring device. The five-axis visual coordinate measuring device includes a workbench, a two-axis turntable, a three-coordinate mobile platform and an industrial camera. The two-axis turntable and the three-coordinate mobile platform are both installed on the workbench. The industrial camera is installed on the Z-axis mobile end of the three-coordinate mobile platform. The target device includes an absolute position target.

[0010] The method comprises the following steps:

[0011] Adjusting the spatial posture of the absolute position target;

[0012] Calibrate the relative position between the absolute position target and the dual-axis turntable, and determine the relative positions of the front surface of the absolute position target, the side surface of the absolute position target, and the upper surface of the absolute position target with respect to the pitch coordinate system O B -X B Y B Z B Origin O B and azimuth coordinate system O C -X C Y C Z C Origin O C The spacing ΔX in the X-axis, Y-axis, and Z-axis directions BS and ΔX CS , ΔY BS and ΔY CS , ΔZ BS and ΔZ CS ;

[0013] Move the industrial camera, and when the front surface of the absolute position target is on the object focal plane of the industrial camera, determine the grating scale reading of the X linear motion axis as the reference coordinate system O S -X S Y S Z S Origin O S X S0 Coordinate components;

[0014] Lock the X axis and move the industrial camera along the Y axis. When the front edge of the absolute position target is at the center of the field of view of the industrial camera, determine the grating scale reading of the Y linear motion axis as the reference coordinate system O S -X S Y S Z S Origin O S Y S0 Coordinate components;

[0015] Lock the X axis and move the industrial camera along the Z axis. When the upper edge of the absolute position target is at the center of the field of view of the industrial camera, determine the grating scale reading of the Z linear motion axis as the reference coordinate system O S -X S Y S Z S Origin O S Z S0 Coordinate components;

[0016] Based on ΔX BS and ΔX CS , ΔY BS and ΔY CS , ΔZ BS and ΔZCS and X S0 Coordinate component, Y S0 Coordinate component, Z S0 Coordinate components, obtain the rotation center coordinates O of the dual-axis turntable B and O C .

[0017] Furthermore, the spatial posture of the absolute position target is adjusted as follows:

[0018] After turning on the power and returning to zero, the target device is installed on the workbench, and the spatial posture and orientation of the absolute position target are adjusted so that the front surface of the absolute position target is parallel to the YOZ plane and the upper surface of the absolute position target is parallel to the XOY plane, and the state of the absolute position target is fixed and remains unchanged.

[0019] Furthermore, the target device also includes a base and a posture adjustment mechanism, the base is fixed on the workbench, the posture adjustment mechanism is installed on the base, and the absolute position target is fixed on the posture adjustment mechanism.

[0020] Furthermore, the posture adjustment mechanism includes a one-dimensional tilt table A, a one-dimensional tilt table B, a one-dimensional rotation table, a plurality of locking nuts and a plurality of adjustment handles, and the absolute position target is installed on the one-dimensional rotation table;

[0021] The one-dimensional tilt table A and the one-dimensional tilt table B are sequentially stacked and respectively used to adjust the rotation angle α of the absolute position target around the X axis and the rotation angle β around the Y axis driven by the corresponding adjustment handle, and are locked in position by the corresponding locking nuts;

[0022] The one-dimensional rotation stage is superimposed on the one-dimensional tilt stage A or the one-dimensional tilt stage B and is used to adjust the rotation angle γ of the absolute position target around the Z axis under the drive of the corresponding adjustment handle, and to lock the position through the corresponding locking nut.

[0023] Furthermore, the absolute position target is made of hard alloy steel material and has a cube shape.

[0024] Furthermore, the visual coordinate measuring device further includes a target device protective cover, which is installed on the workbench and covers the target device.

[0025] Furthermore, the target device protective cover is a cubic hollow shell made of transparent material.

[0026] Furthermore, a window is provided on the front surface of the protective cover of the target device.

[0027] Furthermore, the industrial camera includes an industrial camera, a telecentric lens and a light source, the telecentric lens is installed in a lens interface at the front end of the industrial camera, and the light source is installed at the front end of the telecentric lens.

[0028] Furthermore, the light source is the LED ring light source.

[0029] (3) Beneficial effects

[0030] In summary, the present invention designs an absolute position target with planar features based on the characteristics of the industrial camera and installs it on the workbench of the five-axis visual coordinate measuring device. The position of the absolute position target in the machine coordinate system under different power-on and zero-return states is obtained by the industrial camera, and then integrated with the calibrated relative position relationship data, thereby indirectly obtaining the position of the dual-axis turntable in the machine coordinate system under this state, thereby improving the use efficiency of the visual coordinate measuring device, and having the advantages of simple principle, easy implementation, simple calculation method, etc., and has great practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 This is a flow chart of a method for measuring the coordinates of the center of rotation of a visual coordinate measuring device provided by an embodiment of the present invention;

[0033] Figure 2 1 is a schematic structural diagram of a visual coordinate measurement device provided by an embodiment of the present invention;

[0034] Figure 3 1 is a schematic structural diagram of a target device of a visual coordinate measurement device provided by an embodiment of the present invention;

[0035] Figure 4 1 is a structural schematic diagram of a posture adjustment mechanism of a target device provided by an embodiment of the present invention;

[0036] Figure 5 1 is a schematic structural diagram of an absolute position target of a target device provided by an embodiment of the present invention;

[0037] Figure 6 This is a structural diagram of an industrial camera of a visual coordinate measurement device provided by an embodiment of the present invention;

[0038] Figure 7This is a schematic structural diagram of a target device protective cover provided by an embodiment of the present invention;

[0039] Figure 8 This is a ΔX provided by the embodiment of the present invention. CS (ΔX BS ) and ΔY CS (ΔY BS )

[0040] Figure 9 This is a ΔZ provided by an embodiment of the present invention. CS (ΔZ BS )

[0041] Figure 10 This is a schematic diagram of an image when the front edge of an absolute position target is at the center of the field of view of an industrial camera, provided by an embodiment of the present invention;

[0042] Figure 11 This is a schematic diagram of an image when the edge of an absolute position target is at the center of the field of view of an industrial camera, provided by an embodiment of the present invention.

[0043] In the picture:

[0044] 1-Five-axis visual coordinate measuring device; 11-Workbench; 12-Two-axis rotary table; 13-Three-coordinate mobile platform; 14-Industrial camera; 141-Industrial camera; 142-Telecentric lens; 143-Light source; 2-Target device; 21-Base; 22-Posture adjustment mechanism; 221-One-dimensional tilt table A; 222-One-dimensional tilt table B; 223-One-dimensional rotation table; 224-Locking nut; 225-Adjusting handle; 23-Absolute position target; 231-Front surface of absolute position target; 232-Upper surface of absolute position target; 233-Side surface of absolute position target; 234-Upper edge of absolute position target, 235-Front edge of absolute position target; 3-Protective cover of target device; 31-Front surface of protective cover; 311-Window. DETAILED DESCRIPTION

[0045] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are intended to illustrate the principles of the present invention and are not intended to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments and covers any modifications, replacements, and improvements to the parts, components, and connection methods without departing from the spirit of the present invention.

[0046] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present invention are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0048] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed" and "installed" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0049] Figure 1 FIG. 1 is a flow chart of a method for measuring the coordinates of the center of rotation of a visual coordinate measuring device provided by an embodiment of the present invention. Figure 2 、 Figure 3 、 Figure 7 As shown, the visual coordinate measuring device includes a five-axis visual coordinate measuring device 1 and a target device 2 and a target device protective cover 3 installed on the five-axis visual coordinate measuring device 1. The five-axis visual coordinate measuring device 1 includes a workbench 11, a two-axis turntable 12, a three-coordinate mobile platform 13 and an industrial camera 14. The two-axis turntable 12 and the three-coordinate mobile platform 13 are both installed on the workbench 11. The industrial camera 14 is installed on the Z-axis mobile end of the three-coordinate mobile platform 13. The target device 2 includes an absolute position target 23.

[0050] The method comprises the following steps:

[0051] S100 , adjusting the spatial posture of the absolute position target 23 .

[0052] Specifically, after turning on the power and returning to zero, the target device 2 is installed on the workbench 11, and the spatial posture and orientation of the absolute position target 23 are adjusted so that the front surface 231 of the absolute position target is parallel to the YOZ plane and the upper surface 232 of the absolute position target is parallel to the XOY plane, and the state of the absolute position target 23 is fixed and remains unchanged.

[0053] S200, calibrate the relative position between the absolute position target 23 and the dual-axis turntable 12, and determine the relative positions of the absolute position target front surface 231, the absolute position target side surface 233 and the absolute position target upper surface 232 with the pitch coordinate system O respectively. B -X B Y B ZB Origin O B and azimuth coordinate system O C -X C Y C Z C Origin O C The spacing ΔX in the X-axis, Y-axis, and Z-axis directions BS and ΔX CS , ΔY BS and ΔY CS , ΔZ BS and ΔZ CS .

[0054] Specifically, a micrometer, an inductive micrometer or an industrial camera 14 is used as a calibration tool, and the calibration process is used to determine: Figure 8 As shown, the front surface 231 of the absolute position target is respectively associated with the pitch coordinate system O B -X B Y B Z B Origin O B and azimuth coordinate system O C -X C Y C Z C Origin O C The spacing ΔX in the X-axis direction BS and ΔX CS ;like Figure 8 As shown, the absolute position target side surface 233 is respectively B and O C The distance ΔY in the Y-axis direction BS and ΔY CS ;like Figure 9 As shown, the upper surface 232 of the absolute position target is respectively B and O C The distance ΔZ in the Z-axis direction BS and ΔZ CS .

[0055] S300, move the industrial camera 14, when the absolute position target front surface 231 is on the object focal plane of the industrial camera 14, determine the grating scale reading of the X linear motion axis as the reference coordinate system O S -X S Y S Z S Origin O S X S0 Coordinate components.

[0056] Specifically, the X, Y, and Z axes of the five-axis visual coordinate measuring device 1 are controlled to drive the industrial camera 14 to move, so that the front surface 231 of the absolute position target enters the field of view of the industrial camera 14, and the focus interval and step size in the X-axis direction are set, and automatic focusing is performed to make the industrial camera 14 correctly focus on the front surface 231 of the absolute position target. At this time, the front surface 231 of the absolute position target is on the object focal plane of the industrial camera 14, and the grating scale readings of the three linear motion axes of X, Y, and Z are recorded as (X1, Y1, Z1). Solve O S X S0 Coordinate components, the formula is as follows:

[0057] X S0 =X1 (1)

[0058] S400, lock the X axis and move the industrial camera 14 along the Y axis. When the front edge 235 of the absolute position target is at the center of the field of view of the industrial camera 14, determine the grating scale reading of the Y linear motion axis as the reference coordinate system O S -X S Y S Z S Origin O S Y S0 Coordinate components.

[0059] Specifically, the X axis is locked, and the industrial camera 14 is moved along the positive or negative direction of the Y axis so that the front edge 235 of the absolute position target is at the center of the field of view of the industrial camera 14, as shown in FIG. Figure 10 As shown, the image at this time is collected and the grating scale readings of the three linear motion axes X, Y and Z are recorded as (X2, Y2, Z2) (X2 = X1), and the solution is O S Y S0 Coordinate components, the formula is as follows:

[0060] Y S0 =Y2 (2)

[0061] S500, lock the X axis and move the industrial camera 14 along the Z axis. When the edge 234 on the absolute position target is at the center of the field of view of the industrial camera 14, determine the grating scale reading of the Z linear motion axis as the reference coordinate system O S -X S Y S Z S Origin O S Z S0 Coordinate components.

[0062] Specifically, continue to lock the X axis and move the industrial camera 14 along the positive direction of the Z axis so that the edge 234 of the absolute position target is at the center of the field of view of the industrial camera 14, as shown in FIG. Figure 11As shown, the image at this time is collected and the grating scale readings of the three linear motion axes X, Y and Z are recorded as (X3, Y3, Z3) (X3 = X1), and the solution is O S Z S0 Coordinate components, the formula is as follows:

[0063] Z S0 =Z3 (3)

[0064] S600, based on ΔX BS and ΔX CS , ΔY BS and ΔY CS , ΔZ BS and ΔZ CS and X S0 Coordinate component, Y S0 Coordinate component, Z S0 Coordinate components, obtain the rotation center coordinates O of the dual-axis turntable 12 B and O C .

[0065] Specifically, the reference coordinate system O is determined through the above steps. S -X S Y S Z S The coordinate origin O S The three-dimensional coordinates (X S0 ,Y S0 ,Z S0 ), according to the spacing value ΔX determined by the calibration process in step S200 BS , ΔY BS , ΔZ BS , ΔX CS , ΔY CS and ΔZ CS , solve O in this state B The three-dimensional coordinates (X B0 ,Y B0 ,Z B0 ) and O C The three-dimensional coordinates (X C0 ,Y C0 ,Z C0 ), the formulas are as follows:

[0066]

[0067]

[0068] In the above formula, “+” and “−” need to be specifically determined according to the actual relative position relationship between the dual-axis turntable 12 and the absolute position target 23 in terms of up and down, left and right, and front and back.

[0069] Without disassembling the target device 2 and keeping the relative position relationship between the absolute position target 23 and the dual-axis turntable 12 unchanged, the spacing value ΔX BS , ΔY BS , ΔZ BS , ΔX CS , ΔY CS and ΔZ CS The rotation center O of the dual-axis turntable in the state of power on and zero return can be calculated by performing steps S300, S400, S500 and S600 next time the machine is powered on and zero return is performed. B and O C The three-dimensional coordinates are obtained, thereby completing the initialization of the five-axis vision coordinate measuring device 1, and are applied to the subsequent measurement process to obtain correct multi-view measurement data.

[0070] As an optional implementation, Figure 3 As shown, the target device 2 further includes a base 21 and a posture adjustment mechanism 22 . The base 21 is fixed on the workbench 11 , the posture adjustment mechanism 22 is installed on the base 21 , and the absolute position target 23 is fixed on the posture adjustment mechanism 22 .

[0071] Specifically, the five-axis visual coordinate measuring device 1 has five motion axes: three linear motion axes (X, Y, and Z) and two rotational motion axes (B and C). The three linear motion axes (X, Y, and Z) are perpendicular and integrated, implemented by a three-coordinate motion platform 13. The two rotational motion axes (B and C) are perpendicular and integrated, implemented by a dual-axis turntable 12. The B axis has an angular range of -90° to +90°, and the C axis has an angular range of 0° to 360°.

[0072] like Figure 2 As shown, a three-axis motion platform 13 is mounted on the workbench 11. Each linear axis is equipped with air-bearing guides and high-precision incremental scales to ensure smooth motion and displacement accuracy. A dual-axis rotary table 12 is fixed to the workbench 11. Mechanical alignment and adjustment ensure that the B-axis is parallel to the Y-axis, and the C-axis is parallel to the Z-axis.

[0073] As an optional embodiment, the posture adjustment mechanism 22 includes a one-dimensional tilt table A221, a one-dimensional tilt table B222, a one-dimensional rotation table 223, a plurality of locking nuts 224 and a plurality of adjustment handles 225, and the absolute position target 23 is installed on the one-dimensional rotation table 223;

[0074] The one-dimensional tilt table A221 and the one-dimensional tilt table B222 are installed in sequence and are used to adjust the rotation angle α and the rotation angle β of the absolute position target 23 around the X axis and around the Y axis respectively under the drive of the corresponding adjustment handle 225, and the position is locked by the corresponding locking nut 224;

[0075] The one-dimensional rotating stage 223 is mounted on the one-dimensional tilt stage A221 or the one-dimensional tilt stage B222 and is used to adjust the rotation angle γ of the absolute position target 23 around the Z axis under the drive of the corresponding adjustment handle 225, and is locked in position through the corresponding locking nut 224.

[0076] Specifically, if Figure 4 As shown, since there are three tilt tables and a rotating table, three locking nuts 224 and three adjusting handles 225 are set accordingly. Corresponding locking nuts 224 and adjusting handles 225 are set on the one-dimensional tilt table A221, the one-dimensional tilt table B222 and the one-dimensional rotating table 223. In order to realize the deflection movement of the one-dimensional tilt table A221 and the one-dimensional tilt table B222, the contact surface between the one-dimensional tilt table A221 and the base 21 is set to an arc surface, and the contact surface between the one-dimensional tilt table A221 and the one-dimensional tilt table B222 is set to an arc surface.

[0077] The one-dimensional tilt table A 221 and the one-dimensional tilt table B 222 are adjusted in one-dimensional angular position within a range of -30° to +30° via their respective adjustment handles 225, and are locked in position via their corresponding locking nuts 224. The one-dimensional rotation table 223 is adjusted in one-dimensional angular position within a range of 0° to 360° via its corresponding adjustment handle 225, and is locked in position via its corresponding locking nut 224. Since the locking mechanism between the locking nut 224 and the adjustment handle 225 is conventional, it will not be described in detail here.

[0078] As an optional embodiment, the absolute position target 23 is made of carbide steel and is in the shape of a cube. The absolute position target 23 has good shape and position accuracy, dimensional accuracy, and surface quality. Each surface is a smooth, flat, evenly textured matte surface, and each edge is a sharp straight edge without chamfers or blunting. During the imaging process of the industrial camera 14, a two-dimensional image of the object being measured is formed by projecting a three-dimensional scene onto a two-dimensional image plane, and spatial depth information is lost. Therefore, a standard sphere with three-dimensional spatial characteristics is not suitable as a reference datum for a five-axis visual coordinate measuring device. Since the output of the industrial camera 14 is a two-dimensional image of the object being measured and it is more sensitive to sudden changes such as edges and sharp corners of the object being measured, it is necessary to set a reference datum based on its own characteristics to determine and set a certain datum in the visual coordinate measuring device. Therefore, it is preferred to design the absolute position target 23 into a cubic structure.

[0079] As an optional embodiment, the visual coordinate measuring device further includes a target device protective cover 3 , which is installed on the workbench 11 and covers the target device 2 .

[0080] Specifically, if Figure 7 As shown, the target device protective cover 3 is used to protect the target device 2 from dust, collision, and impact. The target device 2 is located inside the target device protective cover 3 and has no contact with any inner surface of the target device protective cover 3. The target device protective cover 3 can cover the target device 2 from five directions: above, left, right, front, and rear.

[0081] As an optional embodiment, the target device protective cover 3 is a cubic hollow shell made of a transparent material. Such a design facilitates observation and confirmation of the state of the target device 2.

[0082] As an optional embodiment, a window 311 is provided on the front surface 31 of the target device protective cover 3 .

[0083] Specifically, if Figure 7 As shown, a window 311 is provided on the front surface 31 of the protective cover so that the industrial camera 14 can observe the absolute position target front surface 231 , the absolute position target upper edge 234 and the absolute position target front edge 235 .

[0084] As an optional embodiment, the industrial camera 14 includes an industrial camera 141, a telecentric lens 142 and a light source 143. The telecentric lens 142 is installed in the lens interface at the front end of the industrial camera 141, and the light source 143 is installed at the front end of the telecentric lens 142.

[0085] Specifically, if Figure 2 As shown, the industrial camera 14 is the front-end sensor of the five-axis visual coordinate measuring device 1, which is installed on the Z-axis moving end of the three-coordinate mobile platform 13 through a mounting bracket, and the imaging optical axis direction of the industrial camera 14 is parallel to the X-axis direction of the three-coordinate mobile platform 13 through mechanical adjustment.

[0086] As an optional embodiment, the light source 143 is an LED ring light source. The LED ring light source has a wide irradiation area so that the shooting light of the industrial camera 141 meets the requirements.

[0087] It should be noted that the various embodiments in this specification are described in a progressive manner. References to the same or similar parts between the various embodiments are sufficient. Each embodiment focuses on the differences from the 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 technologies are omitted here.

[0088] The above are merely embodiments of the present application and are not intended to limit the present application. Various modifications and variations are possible for those skilled in the art without departing from the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for measuring the coordinates of the center of rotation of a visual coordinate measuring device, characterized in that: The visual coordinate measuring device comprises a five-axis visual coordinate measuring device (1), a target device (2) and a target device protective cover (3) installed on the five-axis visual coordinate measuring device (1), the five-axis visual coordinate measuring device (1) comprises a workbench (11), a two-axis turntable (12), a three-coordinate mobile platform (13) and an industrial camera (14), the two-axis turntable (12) and the three-coordinate mobile platform (13) are both installed on the workbench (11), the industrial camera (14) is installed on the Z-axis mobile end of the three-coordinate mobile platform (13), and the target device (2) comprises an absolute position target (23); wherein, The method comprises the following steps: Adjusting the spatial posture of the absolute position target (23); The relative position between the absolute position target (23) and the dual-axis turntable (12) is calibrated, and the absolute position target front surface (231), the absolute position target side surface (233) and the absolute position target upper surface (232) are respectively determined to be relative to the pitch coordinate system O B -X B Y B Z B Origin O B and azimuth coordinate system O C -X C Y C Z C Origin O C The spacing ΔX in the X-axis, Y-axis, and Z-axis directions BS and ΔX CS , ΔY BS and ΔY CS , ΔZ BS and ΔZ CS ; The industrial camera (14) is moved, and when the front surface (231) of the absolute position target is on the object focal plane of the industrial camera (14), the grating scale reading of the X linear motion axis is determined as the reference coordinate system O S -X S Y S Z S Origin O S X S0 Coordinate components; Lock the X axis and move the industrial camera (14) along the Y axis. When the front edge (235) of the absolute position target is at the center of the field of view of the industrial camera (14), the grating scale reading of the Y linear motion axis is determined as the reference coordinate system O. S -X S Y S Z S Origin O S Y S0 Coordinate components; Lock the X axis and move the industrial camera (14) along the Z axis. When the upper edge (234) of the absolute position target is at the center of the field of view of the industrial camera (14), the grating scale reading of the Z linear motion axis is determined as the reference coordinate system O. S -X S Y S Z S Origin O S Z S0 Coordinate components; Based on ΔX BS and ΔX CS , ΔY BS and ΔY CS , ΔZ BS and ΔZ CS and X S0 Coordinate component, Y S0 Coordinate component, Z S0 Coordinate components, obtain the rotation center coordinates O of the dual-axis turntable (12) B and O C .

2. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 1, characterized in that: The spatial posture of the absolute position target (23) is adjusted as follows: After starting up and returning to zero, the target device (2) is mounted on the workbench (11), and the spatial posture and orientation of the absolute position target (23) are adjusted so that the front surface (231) of the absolute position target is parallel to the YOZ plane and the upper surface (232) of the absolute position target is parallel to the XOY plane, and the state of the absolute position target (23) is fixed and remains unchanged.

3. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 1, characterized in that: The target device (2) further comprises a base (21) and a posture adjustment mechanism (22), wherein the base (21) is fixed on the workbench (11), the posture adjustment mechanism (22) is mounted on the base (21), and the absolute position target (23) is fixed on the posture adjustment mechanism (22).

4. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 3, characterized in that: The attitude adjustment mechanism (22) comprises a one-dimensional tilting table A (221), a one-dimensional tilting table B (222), a one-dimensional rotating table (223), a plurality of locking nuts (224) and a plurality of adjustment handles (225), and the absolute position target (23) is mounted on the one-dimensional rotating table (223); The one-dimensional tilting table A (221) and the one-dimensional tilting table B (222) are sequentially stacked and respectively used to adjust the rotation angle α around the X axis and the rotation angle β around the Y axis of the absolute position target (23) driven by the corresponding adjustment handle (225), and to lock the position through the corresponding locking nut (224); The one-dimensional rotating stage (223) is mounted on the one-dimensional tilting stage A (221) or the one-dimensional tilting stage B (222) and is used to adjust the rotation angle γ of the absolute position target (23) around the Z axis under the drive of the corresponding adjustment handle (225), and to lock the position through the corresponding locking nut (224).

5. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 3, characterized in that: The absolute position target (23) is made of hard alloy steel and has a cube shape.

6. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 1, characterized in that: The visual coordinate measuring device further comprises a target device protective cover (3), which is mounted on the workbench (11) and covers the target device (2).

7. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 6, characterized in that: The target device protective cover (3) is a cubic hollow shell made of a transparent material.

8. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 6 or 7, characterized in that: A window (311) is provided on the front surface (31) of the protective cover of the target device (3).

9. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 1, characterized in that: The industrial camera (14) comprises an industrial camera (141), a telecentric lens (142) and a light source (143); the telecentric lens (142) is installed in a lens interface at the front end of the industrial camera (141); and the light source (143) is installed at the front end of the telecentric lens (142).

10. The method for measuring the coordinates of the center of rotation of the visual coordinate measuring device according to claim 9, characterized in that: The light source (143) is an LED ring light source.

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