Active retroreflective six-dimensional laser tracking measurement system

Abstract

This disclosure describes a six-dimensional laser tracking measurement system with active reverse tracking, comprising: a laser tracker and a probe that cooperates with the laser tracker and is disposed on a target. The laser tracker is configured to emit a laser beam. The probe includes: a target configured to reflect the laser beam, a position sensing unit configured to receive the laser beam, and a tracking control unit. The tracking control unit is configured to control the attitude of the target based on sensing information acquired by the position sensing unit by rotating the target in two directions to enable the probe to actively track the laser tracker. In this configuration, reverse tracking of the target can be achieved through the position sensing unit disposed on the probe, thereby expanding the angular range that the probe can receive.

Description

[0001] This application is a divisional application of the patent application filed on December 12, 2022, with application number 2022115899861 and invention title "Six-Dimensional Laser Tracking Measurement System Based on Reverse Tracking". Technical Field

[0002] This invention relates to the intelligent manufacturing equipment industry, specifically to a six-dimensional laser tracking and measurement system for active reverse tracking. Background Technology

[0003] In precision industry and measurement fields, when assembling targets (such as machines), precision instruments are often used to measure the assembled targets to improve assembly accuracy. After the target assembly is completed, the machine also needs to be calibrated. When measuring the three-dimensional coordinates of a target or a target point on a target, it is also necessary to measure their attitude. Therefore, an attitude detection device that can simultaneously measure the three-dimensional coordinates and attitude of a target is needed.

[0004] Common attitude detection devices include a tracking head for emitting and receiving laser beams and a probe positioned on the target (e.g., a workpiece) to reflect the laser beam. The laser beam measures the three-dimensional coordinates of the probe, and a light source mounted on the probe acquires the probe's attitude. However, as the target's attitude changes, the laser beam may exceed the probe's acceptable angle range (typically ±45°), causing the probe's reflector to fail to receive the laser beam, thus affecting the measurement results. To address this, existing technology discloses an attitude detection device that allows the probe to actively track (i.e., reverse track) the tracking head. For example, Chinese Patent Publication No. CN112424563A discloses a multi-dimensional measurement system for accurately calculating the position and orientation of a dynamic object, utilizing a probe to actively track the tracking head and expanding the acceptable angle range of the reflective element by changing the probe's attitude.

[0005] However, the aforementioned Chinese patent requires the installation of a first and a second light-emitting device on the probe. Only then can the probe's orientation be calculated based on the spatial distribution of these two devices. Furthermore, at least three rotation axes are needed to control the probe's orientation. In this case, the probe's complex structure leads to higher manufacturing and design costs. Summary of the Invention

[0006] This disclosure is made in view of the above-mentioned situation, and its purpose is to provide a six-dimensional laser tracking measurement system that simplifies the probe structure, enables reverse tracking, and expands the angular range that the probe can receive.

[0007] To this end, this disclosure provides a six-dimensional laser tracking measurement system based on reverse tracking, which is used to track a target and obtain the position and attitude of the target. The system includes: a laser tracker and a probe that cooperates with the laser tracker to obtain the position and attitude of the target. The laser tracker includes: a laser emitting unit configured to emit a laser beam; a first position sensing unit configured to receive a laser beam reflected by the probe; a first tracking control unit configured to control the emission direction of the laser emitting unit to make the laser emitting unit track the probe; a light emitting unit configured to emit a diverging beam; and a target acquisition unit configured to receive the diverging beam reflected by the probe. The probe includes: a fixed base configured to mount the probe on the target; a target configured to reflect a laser beam or a diverging beam and having a through-hole; a second position sensing unit configured to receive a laser beam passing through the through-hole; and a second tracking control unit configured to control the attitude of the target based on sensing information obtained by the second position sensing unit to make the target align with the laser emitting unit.

[0008] In this configuration, the target acquisition unit captures the divergent beam emitted by the light-emitting unit and reflected by the probe. The laser tracker can initially calculate the probe's position based on this beam. Then, the first tracking control unit drives the laser emitting unit to roughly aim at the target. Based on the position information obtained by the first position sensing unit, the laser emitting unit's attitude is further controlled to precisely align with the target. This allows for continuous or real-time acquisition of the beam reflected back from the target while the target is moving, enabling the calculation of the target's spatial position and the target's spatial position. Simultaneously, the second position sensing unit receives the laser beam passing through the through-hole, allowing the determination of whether the laser beam has passed through the target's through-hole. Based on the laser beam's spot position in the second tracking control unit, the angle of the laser beam relative to the target can be determined. The second tracking control unit can control the target's attitude based on the sensing information from the second position sensing unit to align the target with the laser emitting unit. Thus, the second tracking control unit enables the target to track the laser tracker in reverse and expands the probe's receivable angle range.

[0009] Additionally, in the six-dimensional laser tracking measurement system disclosed herein, optionally, the first tracking control unit includes a first rotation mechanism for controlling the laser emitting unit to rotate along a first direction and a second rotation mechanism for controlling the laser emitting unit to rotate along a second direction. In this case, the first rotation mechanism can be used to control the laser emitting unit to rotate along the first direction to track the target in the first direction, and the second rotation mechanism can be used to control the laser emitting unit to rotate along the second direction to track the target in the second direction.

[0010] Additionally, in the six-dimensional laser tracking measurement system disclosed herein, optionally, the laser tracker includes a tracking head angle measurement unit. This tracking head angle measurement unit includes a first tracking head angle measurement unit configured to measure the rotation angle of the laser emitting unit along the first direction and a second tracking head angle measurement unit configured to measure the rotation angle of the laser emitting unit along the second direction. In this case, the rotation angles of the laser emitting unit along the first direction and the second direction can be obtained. Based on these rotation angles, the orientation of the target in the coordinate system of the laser tracker can be calculated. Combined with the distance to the target obtained by the distance measurement module, the specific position coordinates of the target in the coordinate system of the laser tracker can then be calculated.

[0011] Additionally, in the six-dimensional laser tracking and measurement system disclosed herein, optionally, the laser tracker includes a first gravity alignment unit. This first gravity alignment unit is configured to acquire a first tilt angle, which is configured to align the first direction information acquired by the tracking head angle measurement unit to the target coordinate system. The first direction information includes the rotation angle of the laser emitting unit along the first direction and the rotation angle of the laser emitting unit along the second direction. In this case, since the rotation angles of the laser emitting unit along the first and second directions measured by the tracking head angle measurement unit can obtain the specific position coordinates of the target in the laser tracker's coordinate system, and aligning the first direction information to the target coordinate system can obtain the target's orientation in the target coordinate system, the specific position coordinates of the target in the target coordinate system can be calculated.

[0012] Additionally, in the six-dimensional laser tracking measurement system disclosed herein, optionally, the second tracking control unit includes a third rotation mechanism for controlling the target to rotate along a third direction and a fourth rotation mechanism for controlling the target to rotate along a fourth direction. In this case, the third rotation mechanism can be used to control the target to rotate along a third direction to track the laser tracker in the third direction, and the fourth rotation mechanism can be used to control the target to rotate along a fourth direction to track the laser tracker in the fourth direction.

[0013] Additionally, in the six-dimensional laser tracking and measurement system disclosed herein, optionally, the probe includes a probe angle measurement unit. This probe angle measurement unit comprises a first probe angle measurement unit configured to measure the rotation angle of the target along the third direction and a second probe angle measurement unit configured to measure the rotation angle of the target along the fourth direction. In this case, the rotation angles of the target along the third direction and the fourth direction can be obtained, and thus the direction vector of the laser beam in the target coordinate system can be calculated based on these rotation angles.

[0014] Additionally, in the six-dimensional laser tracking measurement system disclosed herein, optionally, the probe includes a second gravity alignment unit disposed on the fixed base. The second gravity alignment unit is configured to acquire a second tilt angle of the probe, and the second tilt angle is configured to calculate the transformation relationship between the target coordinate system and the target coordinate system. In this case, the direction vector of the laser beam in the laser tracker device coordinate system and the direction vector of the laser beam in the target coordinate system can be correlated. Furthermore, since the transformation relationship between the target coordinate system and the target coordinate system can be obtained using the Euler angles of the target (including pitch, roll, and yaw angles), the yaw angle of the target can be calculated when the direction vector of the laser beam in the laser tracker device coordinate system, the direction vector of the laser beam in the target coordinate system, the pitch angle of the target, and the roll angle of the target are known. Simultaneously, since the fixed base is mounted on the target and remains relatively stationary, the second gravity alignment unit can remain fixed relative to the target without rotating with the target, thus enabling the measurement of the target's tilt angle. In addition, compared to the scheme where the second gravity alignment unit is placed on the target, that is, the second gravity alignment unit rotates under the drive of the third or fourth rotation mechanism, the dynamic response requirements of the second gravity alignment unit can be reduced, thereby improving the measurement accuracy of the second gravity alignment unit and simplifying the calculation process.

[0015] Furthermore, in the six-dimensional laser tracking and measurement system disclosed herein, optionally, the second gravity alignment unit includes a first inclinometer and a second inclinometer. The mounting direction of the first inclinometer is perpendicular to the extension direction of the rotation axis of the third rotation mechanism, and the mounting direction of the second inclinometer is parallel to the extension direction of the rotation axis of the fourth rotation mechanism. In this case, since the sensitive axis of the second gravity alignment unit matches the rotation axis of the second tracking control unit, the transformation formula between the target coordinate system and the objective coordinate system can be simplified, the calculation speed can be improved, and the measurement accuracy can be enhanced.

[0016] Furthermore, in the six-dimensional laser tracking measurement system disclosed herein, optionally, the first tracking control unit is configured to control the attitude of the laser emitting unit based on the sensing information acquired by the first position sensing unit so that the laser emitting unit is aligned with the target. In this case, the first tracking control unit can control the laser emitting unit to track the target based on the calculation result of the attitude adjustment method. At the same time, due to the high accuracy of the first position sensing unit, precise aiming of the six-dimensional laser tracking measurement system can be achieved.

[0017] Furthermore, in the six-dimensional laser tracking and measurement system disclosed herein, optionally, the first tracking control unit is configured to control the attitude of the laser emitting unit based on the diverging beam acquired by the target acquisition unit so that the laser emitting unit is aligned with the target. In this case, it is possible to quickly determine whether the laser emitting unit has acquired the target, and thus it is possible to quickly control the direction of the laser beam emitted by the laser emitting unit so that the laser beam gradually approaches the target.

[0018] According to this disclosure, a six-dimensional laser tracking measurement system is provided that simplifies the probe structure, enables reverse tracking, and expands the angular range that the probe can receive. Attached Figure Description

[0019] Embodiments of this disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram illustrating an application scenario of the six-dimensional laser tracking measurement system involved in the examples of this disclosure.

[0021] Figure 2 This is a planar schematic diagram of the laser tracker of the six-dimensional laser tracking measurement system involved in the example of this disclosure.

[0022] Figure 3 This is a three-dimensional schematic diagram of a laser tracker for a six-dimensional laser tracking measurement system as described in this disclosure.

[0023] Figure 4 This is a plan view of the measurement host of the laser tracker in the six-dimensional laser tracking measurement system involved in the example of this disclosure.

[0024] Figure 5a This is a schematic diagram illustrating the structure of a first embodiment of the internal optical path of the measurement host involved in the examples of this disclosure.

[0025] Figure 5b This is a schematic diagram illustrating a second embodiment of the internal optical path of the measurement host involved in the examples of this disclosure.

[0026] Figure 5cThis is a schematic diagram illustrating a third embodiment of the internal optical path of the measurement host involved in the examples of this disclosure.

[0027] Figure 6 This is a plan view showing the first tracking control unit and the measurement host inside the laser tracker of the six-dimensional laser tracking measurement system involved in this disclosure example.

[0028] Figure 7 This is a schematic diagram illustrating the first plane, first direction, axis of the first rotation axis, second plane, second direction, and axis of the second rotation axis involved in the examples of this disclosure.

[0029] Figure 8 This is a schematic diagram showing the probe of the six-dimensional laser tracking measurement system involved in the example of this disclosure.

[0030] Figure 9 This is a schematic diagram illustrating the third plane, third direction, axis of the third rotation axis, fourth plane, fourth direction, and axis of the fourth rotation axis involved in the examples of this disclosure.

[0031] Figure 10 This illustrates the probe of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 8 A cross-sectional view of the M-M' position.

[0032] Figure 11 This illustrates the target and fourth rotation axis of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 8 A cross-sectional view of the N-N' position in the diagram.

[0033] Figure 12 This is a front view showing a portion of the structure of the probe of the six-dimensional laser tracking measurement system involved in the example of this disclosure.

[0034] Figure 13 This illustrates a partial structure of the probe of the six-dimensional laser tracking measurement system described in this disclosure example. Figure 12 A cross-sectional view of the O-O' position in the diagram.

[0035] Figure 14 This illustrates a partial structure of the target in the six-dimensional laser tracking measurement system described in this disclosure example. Figure 12 A cross-sectional view of the O-O' position in the diagram.

[0036] Figure 15 This is a bottom view showing a portion of the structure of the probe of the six-dimensional laser tracking measurement system involved in this disclosure example.

[0037] Figure 16 This is a flowchart illustrating the 6D pose detection method involved in the example of this disclosure. Detailed Implementation

[0038] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same components, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the components or the shapes of the components may differ from actual figures.

[0039] It should be noted that the terms "comprising" and "having," and any variations thereof, meaning a process, method, system, product, or apparatus that includes or has a series of steps or units, are not necessarily limited to those steps or units explicitly listed, but may include or have other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. All methods described in this disclosure may be performed in any suitable order unless otherwise indicated herein or clearly contradicted by the context.

[0040] This disclosure relates to a six-dimensional laser tracking measurement system based on reverse tracking, including a laser tracker and a probe that works in conjunction with the laser tracker. The probe expands the angular range that it can receive by actively tracking the laser tracker.

[0041] This disclosure relates to a six-dimensional laser tracking measurement system based on reverse tracking, including a laser tracker and a probe that works with the laser tracker and is positioned on a target. The probe includes a target, a third rotation mechanism for controlling the horizontal rotation of the target, and a fourth rotation mechanism for controlling the pitch rotation of the target. In this configuration, not only can the third and fourth rotation mechanisms be used to control the target to align with the laser tracker, but the target's attitude can also be calculated based on the target's rotation angle.

[0042] This disclosure relates to a six-dimensional laser tracking measurement system based on reverse tracking, including a laser tracker and a probe that cooperates with the laser tracker. The laser tracker includes a laser emitting unit that emits a laser beam and a first position sensing unit that receives the laser beam reflected by the probe. In this configuration, the position of the probe can be initially calculated based on the sensing information obtained by the first position sensing unit, and the laser tracker can be controlled to capture the probe, thereby enabling a fine target aiming function to be activated after the laser tracker captures the probe.

[0043] This disclosure relates to a six-dimensional laser tracking measurement system based on reverse tracking, including a laser tracker and a probe that works in conjunction with the laser tracker. The laser tracker and probe work together to obtain the spatial position of the target. A second gravity alignment unit disposed on the probe obtains the pitch and roll angles in the target's spatial attitude. Through the reverse tracking function of the target, a tracking head angle measurement unit, a first gravity alignment unit, and a second gravity alignment unit work together to calculate the yaw angle. In this configuration, the six-dimensional coordinates of the probe can be obtained, and compared to solutions requiring at least three rotation axes or light-emitting devices on the probe, the design and manufacturing costs of the probe can be reduced.

[0044] In some examples, a six-dimensional laser tracking measurement system based on reverse tracking can also be called a six-dimensional laser tracking measurement system, a 6D attitude detection device, an active reverse tracking 6D attitude detection device, a six-dimensional attitude detection device, or an attitude detection device, etc.

[0045] In some examples, six dimensions (6D) can refer to the target's three position coordinates and three attitude angles (Eulerian angles) in space. In other words, a six-dimensional laser tracking measurement system can be used to measure the target's spatial position and attitude. Spatial position measurement corresponds to the target's spatial position, which can be represented by its position coordinates. Spatial attitude measurement corresponds to the target's spatial attitude, which can be represented by its Euler angles, including yaw, pitch, and roll. In some examples, the target's position coordinates can be used as the target's position coordinates. In other examples, the target's position coordinates can be calculated based on the target's position coordinates.

[0046] In some examples, reverse tracking can refer to the probe actively tracking the laser tracker in a six-dimensional laser tracking measurement system. In some examples, probe-active tracking of the laser tracker can be understood as follows: since the laser tracker may include a laser emitting unit (described later) that emits a laser beam, and the probe may include a target that reflects the laser beam and has a through-hole, when at least a portion of the laser beam emitted by the laser emitting unit passes through the through-hole and is parallel to the optical axis of the target, the target (or probe) can be considered aligned with the laser emitting unit (or laser tracker). During target movement or changes in target attitude, by controlling the attitude of the target to keep the probe continuously aligned with the laser emitting unit, probe reverse tracking (i.e., probe-active tracking of the laser tracker) can be considered.

[0047] In some examples, the alignment of a laser tracker with a target (or probe) can be understood as follows: when the target can receive the laser beam emitted by the laser tracker, and at least a portion of the laser beam passes through a through-hole, and the spot formed by the laser beam reflected from the target at the first position sensing unit is located at a first preset zero point, then the laser tracker can be considered aligned with the target (or probe). In some examples, when at least a portion of the laser beam forms a second spot at the second position sensing unit of the target, the laser tracker can also be considered aligned with the target (or probe). It should be noted that when the laser emitting unit (or laser tracker) is aligned with the target (or probe), the target (or probe) is not necessarily aligned with the laser emitting unit (or laser tracker); when the target (or probe) is aligned with the laser emitting unit (or laser tracker), the laser emitting unit (laser tracker) is not necessarily aligned with the target (or probe).

[0048] In addition, this disclosure also includes descriptions of orientation, such as "front" and "rear". For a laser tracker or other components or units disposed on the laser tracker (e.g., a laser emitting unit, target acquisition unit, or light-emitting unit), "front" can refer to the direction from the laser tracker to the target when the laser tracker is aligned with the target; "rear" can refer to the direction from the target to the laser tracker when the laser tracker is aligned with the target. For a target or other components or units disposed on the target (e.g., a through-hole or a second position sensing unit), "front" can refer to the direction from the target to the laser tracker when the target is aligned with the laser tracker; "rear" can refer to the direction from the laser tracker to the target when the laser tracker is aligned with the target.

[0049] Figure 1 This is a schematic diagram illustrating an application scenario of the six-dimensional laser tracking measurement system involved in the examples of this disclosure. Figure 2 This is a planar schematic diagram of the laser tracker 1 of the six-dimensional laser tracking measurement system involved in the example of this disclosure. Figure 3 This is a three-dimensional schematic diagram of the laser tracker 1 of the six-dimensional laser tracking measurement system involved in the example of this disclosure. Figure 4 This is a plan view of the measurement host 11 of the laser tracker 1 of the six-dimensional laser tracking measurement system involved in the example of this disclosure. Figure 5a This is a structural schematic diagram illustrating a first embodiment of the internal optical path of the measurement host 11 involved in the example of this disclosure. Figure 5b This is a schematic diagram illustrating a second embodiment of the internal optical path of the measurement host 11 involved in the example of this disclosure. Figure 5c This is a structural schematic diagram illustrating a third embodiment of the internal optical path of the measurement host 11 involved in the examples of this disclosure. Figure 6This is a plan view showing the first tracking control unit 13 and the measurement host 11 inside the laser tracker 1 of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 7 This is a schematic diagram showing the first plane S1, the first direction D1, the axis A1 of the first rotation axis 1311, the second plane S2, the second direction D2, and the axis A2 of the second rotation axis 1321 involved in the example of this disclosure.

[0050] In some examples, a six-dimensional laser tracking measurement system can be a six-dimensional laser tracking measurement system used to track a target and obtain the target's position and orientation. In some examples, a six-dimensional laser tracking measurement system can include a laser tracker 1 and a probe 2 that works in conjunction with the laser tracker 1 to obtain the target's position and orientation.

[0051] In some examples, probe 2 can be mounted on a target. In some examples, when probe 2 is mounted on a target, at least a portion of probe 2 (e.g., the mounting base 22 described later) can remain relatively stationary with respect to the target. In some examples, probe 2 may include a target 21 and a mounting base 22 (described later) for mounting probe 2 on the target. In this case, the position and attitude of the target can be obtained by using probe 2 mounted on the target in conjunction with laser tracker 1.

[0052] In some examples, the target can be a workpiece, or any object whose spatial position and / or spatial orientation needs to be measured.

[0053] See in some examples Figure 1 , Figure 2 and Figure 3 The laser tracker 1 may include: a laser emitting unit 12, a first position sensing unit 116, and a first tracking control unit 13 configured to control the emission direction of the laser emitting unit 12. In this case, the first tracking control unit 13 can be used to drive the laser emitting unit 12 to track the target 21, thereby enabling the continuous or real-time acquisition of the beam reflected back from the target 21 while the target is moving, and thus enabling the calculation of the spatial position of the target 21 and the spatial position of the target.

[0054] In some examples, the laser tracker 1 may include a light-emitting unit 14 and a target acquisition unit 15. In this case, the laser tracker 1 can emit a diverging beam using the light-emitting unit 14 and capture the diverging beam emitted by the light-emitting unit 14 and reflected by the probe 2 using the target acquisition unit 15, and can preliminarily calculate the position of the probe 2 based on the beam.

[0055] In some examples, the probe 2 may include a mounting base 22 and a target 21 with a through hole 2122. In this case, the probe 2 can be mounted on the target using the mounting base 22, and the target 21 can reflect the beam emitted by the laser tracker 1 (e.g., a laser beam and / or a diverging beam).

[0056] In some examples, probe 2 may include a fixed base 22, a target 21 with a through-hole 2122, and a second position sensing unit 2131. In this case, a laser beam passing through the through-hole 2122 can be received, thereby determining whether the laser beam has passed through the through-hole 2122 of the target 21, and simultaneously determining whether the angle of the laser beam relative to the target 21 has changed based on the spot position of the laser beam in the second tracking control unit. When the spatial position or spatial attitude of the target changes, the spatial position or spatial attitude of the target 21 and probe 2 can be linked. When the laser emitting unit 12 is aligned with the target 21, the laser emitting unit 12 is also aligned with the probe 2. At the same time, when the target 21 is aligned with the laser emitting unit 12, the probe 2 is also aligned with the laser emitting unit 12. Furthermore, the relationship between the spatial position and spatial attitude of the target 21 and the spatial position and spatial attitude of the target can be determined, thereby enabling the calculation of the target's spatial position and spatial attitude.

[0057] In some examples, probe 2 may include a second position sensing unit 2131 and a second tracking control unit. In this case, the second tracking control unit can control the attitude of target 21 based on the sensing information of the second position sensing unit 2131 so that target 21 is aligned with laser emitting unit 12. Since the second tracking control unit can make target 21 track laser tracker 1 in reverse, the receivable angle range of probe 2 can be expanded.

[0058] The following further explains the contents of each part of the six-dimensional laser tracking measurement system.

[0059] In some examples, when using a six-dimensional laser tracking measurement system, the laser tracker 1 can be set up independently of the probe 2. In some examples, the laser tracker 1 can be set on the ground, and the probe 2 can be set on the target. In this case, the spatial position of the probe 2 can be captured using the laser tracker 1 set on the ground.

[0060] See in some examples Figure 2 and Figure 3The laser tracker 1 may include a measurement host 11, which may include a housing and a cavity configured to accommodate components. In some examples, the cavity may be an internal chamber formed by the housing. In this case, the housing can protect the components. In some examples, the components disposed in the internal chamber may include at least one of a laser emitting unit 12, a first position sensing unit 116, and a target acquisition unit 15. However, this disclosure is not limited thereto, and some components of the laser tracker 1 may also be disposed on the outer surface of the housing.

[0061] In some examples, the measurement host 11 may be provided with components for accommodating the emission and reception of laser beams and / or diverging beams. See also [reference needed] for some examples. Figure 4 The housing may include a light-transmitting opening and a window 115 disposed within the light-transmitting opening. In some examples, the window 115 may be made of a light-transmitting material. In this case, laser beams can be emitted and received through the light-transmitting opening, thereby enabling the acquisition of the spatial position of the probe 2.

[0062] See in some examples Figure 5a , Figure 5b and Figure 5c The laser tracker 1 may include a laser emitting unit 12, which may be configured to emit a laser beam.

[0063] In some examples, the laser beam emitted by the laser emitting unit 12 can be emitted to the window 115 through optical elements such as the reflection unit 111 or the beam combining unit 112, and then emitted from the measurement host 11 at the window 115. In some examples, the laser beam emitted by the laser emitting unit 12 can also be coupled to an optical fiber, emitted through the optical fiber to multiple optical elements, and finally emitted to the window 115.

[0064] In some examples, the reflecting unit 111 can change the propagation direction of the light beam by reflection. In some examples, the reflecting unit 111 can be a reflector.

[0065] In some examples, beam combiner 112 can cause the light beam to reflect or refract. In some examples, beam combiner 112 can be a dichroic mirror.

[0066] In some examples, the laser tracker 1 may have only one laser emitting unit 12. In this case, the internal structure of the laser tracker 1 can be effectively simplified, thereby further reducing the manufacturing and design costs of the laser tracker 1.

[0067] See in some examples Figure 5cThe laser tracker 1 may also include multiple laser emitting units 12. Specifically, the multiple laser emitting units 12 may include a first laser emitting unit for absolute ranging and a second laser emitting unit for interferometric ranging. In other words, the laser tracker 1 may include an absolute ranging module 113 and an interferometric ranging module 114. In this case, the position coordinates of the target 21 can be obtained simultaneously using the absolute ranging module 113 and the interferometric ranging module 114, improving measurement accuracy. Furthermore, compared to measuring distance using only the absolute ranging module 113, the interferometric ranging module 114 has a faster ranging speed, thus also improving measurement speed. In some examples, the distance from the mechanical zero point of the laser tracker 1 to the center of the cone can be obtained using the absolute ranging module 113 and the interferometric ranging module 114, and then the position coordinates of the target can be calculated based on the rotation angle of the laser tracker 1 obtained by the tracking head angle measurement unit.

[0068] In some examples, the absolute ranging module 113 may include a first laser emitting unit, and the interferometric ranging module 114 may include a second laser emitting unit. However, this disclosure is not limited thereto; see [link to relevant documentation]. Figure 5a The second laser emitting unit can also be independent of the interferometric ranging module 114.

[0069] In some examples, the first laser emitting unit can be configured to emit a first laser beam, and the second laser emitting unit can be configured to emit a second laser beam. The optical paths of the first laser beam and the second laser beam can be coupled through the beam combining unit 112. For details, see [link to documentation]. Figure 5a The transmitted light from the first laser beam in the beam combining unit 112 and the reflected light from the second laser beam in the beam combining unit 112 can be combined and emitted jointly from the measurement host 11. However, this disclosure is not limited thereto; see [link to relevant documentation]. Figure 5b The transmitted light from the second laser beam in the beam combining unit 112 and the reflected light from the first laser beam in the beam combining unit 112 can be combined and emitted together from the measurement host 11. In this case, since the first laser beam and the second laser beam are combined, the measurement position of the absolute ranging module 113 (the position where the first laser beam is reflected from the target 21) can coincide with the measurement position of the interferometric ranging module 114 (the position where the second laser beam is reflected from the target 21), thereby improving the accuracy of the position coordinates of the target 21.

[0070] In some examples, the laser emitting unit 12 can be a helium-neon laser or a solid-state laser.

[0071] See in some examples Figure 5a , Figure 5b and Figure 5cThe laser tracker 1 may also include a first position sensing unit 116, which may be configured to receive a laser beam reflected by the probe 2, the laser beam including a first laser beam and / or a second laser beam.

[0072] In some examples, the laser beam reflected by probe 2 can be called the reflected laser beam, the first laser beam reflected by probe 2 can be called the first reflected laser beam, and the second laser beam reflected by probe 2 can be called the second reflected laser beam.

[0073] See in some examples Figure 5a The second laser beam can sequentially pass through the beam splitting unit 117 and the reflection unit 111 and reach the beam combining unit 112. In some examples, the beam splitting unit 117 can be configured to receive the second reflected laser beam and reflect it to the first position sensing unit 116. In this case, the second reflected laser beam can be received, and the position of the spot of the second reflected laser beam can be obtained using the first position sensing unit 116. However, this disclosure is not limited to this; the beam splitting unit 117 can also be disposed in the optical path of the first laser beam, and the beam splitting unit 117 can be configured to receive the first reflected laser beam and reflect it to the first position sensing unit 116.

[0074] In some examples, the mounting position of the beam splitting unit 117 (or the first position sensing unit 116) can be selected based on the layout of the internal cavity of the measuring host 11, and placed in the optical path of the first laser beam, the optical path of the second laser beam, or the optical path after the first and second laser beams are combined. In this case, the flexibility of the internal cavity layout of the measuring host 11 can be improved.

[0075] In some examples, the first position sensing unit 116 may have a photosensitive surface. After receiving the reflected laser beam, the first position sensing unit 116 can determine whether the laser emitting unit 12 is aligned with the probe 2 based on the first light spot formed by the reflected laser beam on the photosensitive surface of the first position sensing unit 116.

[0076] In some examples, the first position sensing unit 116 can record the position of the first light spot on the photosensitive surface of the first position sensing unit 116. In this case, the attitude adjustment mode of the laser emitting unit 12 can be calculated based on the position of the first light spot on the photosensitive surface of the first position sensing unit 116. In some examples, the attitude adjustment mode of the laser emitting unit 12 can be determined based on the relative position between the first light spot and a first preset zero point of the first position sensing unit 116, where the first preset zero point can be located at the position of the first light spot when the laser emitting unit 12 is aligned with the target 21. In this case, the laser beam reflected by the target 21 can be continuously aligned with a fixed point or servo zero point (i.e., the first preset zero point) in the first position sensing unit 116. It should be noted that the relative position between the first light spot and the first preset zero point of the first position sensing unit 116 can refer to the position of the first light spot relative to the first preset zero point.

[0077] In some examples, the first position sensing unit 116 can be used for fine aiming in a six-dimensional laser tracking measurement system. Fine aiming can refer to the laser emitting unit 12 aligning with the target 21 with high precision. In some examples, fine aiming can refer to using the first position sensing unit 116 to receive the laser beam reflected from the target 21, and determining whether the laser emitting unit 12 is aligned with the target 21 with high precision based on the position of the first light spot formed by the first position sensing unit 116 of the laser beam reflected from the target 21, and controlling the attitude of the laser emitting unit 12 based on the position of the first light spot. In this case, since the first position sensing unit 116 receives the laser beam reflected from the target 21 and has high accuracy and sensitivity, it can control the laser emitting unit 12 to align with and track the target 21 in real time with high precision.

[0078] In some examples, the first position sensing unit 116 can acquire the position of the first light spot in real time. In other words, after the first position sensing unit 116 forms the first light spot, it can continuously acquire the position of the first light spot. In this case, it is possible to continuously determine whether the laser emitting unit 12 is aligned with the target 21, thereby enabling the determination of the attitude adjustment mode of the laser emitting unit 12 in real time, and controlling the first tracking control unit 13 (described later) based on the attitude adjustment mode of the laser emitting unit 12 to align the laser emitting unit 12 with the target 21 in real time.

[0079] In some examples, the first position sensing unit 116 may be a position sensor (PSD) or a CCD (charge coupled device) camera.

[0080] See in some examples Figure 2 or Figure 3The laser tracker 1 may include a first tracking control unit 13, which may be configured to control the emission direction of the laser emitting unit 12 so that the laser emitting unit 12 tracks the probe 2.

[0081] In some examples, the laser beam emitted by the laser emitting unit 12 may be refracted or reflected, or the laser emitting unit 12 may even be located outside the measuring host 11, and the optical path of the laser beam may be adjusted by optical fiber or other optical elements so that the laser beam is emitted from the measuring host 11. The rotation of the laser emitting unit 12 may be caused by instructing the laser beam emitted by the laser emitting unit 12 to rotate.

[0082] In some examples, the first tracking control unit 13 may include controlling the laser emitting unit 12 along a first direction D1 (see...). Figure 7 The first rotating mechanism 131 rotates. In this case, the laser emitting unit 12 can be controlled to rotate along the first direction D1 to track the target 21 in the first direction D1 using the first rotating mechanism 131.

[0083] In some examples, the first tracking control unit 13 may include controlling the laser emitting unit 12 along the second direction D2 (see...). Figure 7 The second rotating mechanism 132 rotates the laser emitting unit 12. In this case, the second rotating mechanism 132 can be used to control the laser emitting unit 12 to rotate along the second direction D2 to track the target 21 in the second direction D2.

[0084] See in some examples Figure 7 The rotation of the laser emitting unit 12 along the first direction D1 can mean that the laser emitting unit 12 rotates within the first plane S1, which is perpendicular to the first rotation axis 1311. At this time, the laser emitting unit 12 can rotate around the first rotation axis 1311.

[0085] In some examples, the first plane S1 can be a horizontal plane. In other words, when the laser emitting unit 12 rotates along the first direction D1, the first rotation axis 1311 can be perpendicular to the horizontal plane. In some examples, the laser emitting unit 12 rotates in a horizontal plane, and the first rotation axis 1311 can also be called a horizontal rotation axis. However, this disclosure is not limited to this. In some examples, when the first rotation mechanism 131 drives the laser emitting unit 12 to rotate, the laser emitting unit 12 can also rotate in any plane, that is, when the laser emitting unit 12 rotates along the first direction D1, the first rotation axis 1311 of the first rotation mechanism 131 can be in any direction.

[0086] See in some examples Figure 7The laser emitting unit 12 rotating along the second direction D2 can mean that the laser emitting unit 12 can rotate within the second plane S2. The second plane S2 is perpendicular to the second rotation axis 1321. The second plane S2 does not coincide with or parallel to the first plane S1. At this time, the laser emitting unit 12 can rotate around the second rotation axis 1321.

[0087] It should be noted that, due to possible processing and assembly errors, the parallel, perpendicular, or intersecting positional relationships mentioned in this article do not mean that the two objects must be in a perfect parallel, perpendicular, or intersecting positional relationship without any errors. Rather, it means that within a certain error range, the two objects can be considered to be in a parallel, perpendicular, or intersecting positional relationship.

[0088] In some examples, the second plane S2 can be a vertical plane. In other words, when the laser emitting unit 12 rotates along the second direction D2, the second rotation axis 1321 can be parallel to the horizontal plane. In some examples, when the laser emitting unit 12 rotates in a vertical plane, the second rotation axis 1321 can also be called the pitch rotation axis. However, this disclosure is not limited to this. In some examples, when the second rotation mechanism 132 drives the laser emitting unit 12 to rotate, the laser emitting unit 12 can also rotate in any plane, that is, when the laser emitting unit 12 rotates along the second direction D2, the second rotation axis 1321 of the second rotation mechanism 132 can be in any direction.

[0089] In some examples, the first rotation axis 1311 can be perpendicular to the second rotation axis 1321. In other words, the first plane S1 can be perpendicular to the second plane S2. In this case, the attitude adjustment method of the laser emitting unit 12 can be conveniently decomposed into rotation along the first direction D1 and rotation along the second direction D2, thereby enabling the first rotation mechanism 131 and the second rotation mechanism 132 to conveniently control the laser emitting unit 12 to face any direction, that is, to control the laser beam emission direction of the laser emitting unit 12 to point in any direction.

[0090] In some examples, the axis A1 of the first rotation axis 1311 may intersect the axis A2 of the second rotation axis 1321 (see [reference]). Figure 7 In some examples, when the first rotation axis 1311 is a horizontal rotation axis and the second rotation axis 1321 is a pitch rotation axis, the axis of the horizontal rotation axis can intersect the axis of the pitch rotation axis. In this case, the intersection of the horizontal rotation axis and the pitch rotation axis can be used as the origin of the coordinate system of the laser tracker device, thereby simplifying the calculation, improving the calculation speed, and improving the accuracy of the calculation.

[0091] In some examples, the coordinate system of the laser tracker device can be a coordinate system with the intersection of the axis A1 of the first rotation axis 1311 and the axis A2 of the second rotation axis 1321 as the origin, the direction of the axis A1 of the first rotation axis 1311 as the Z-axis direction, the direction of the axis A2 of the second rotation axis 1321 as the Y-axis direction, and the direction perpendicular to the axis A1 of the first rotation axis 1311 and the axis A2 of the second rotation axis 1321 as the X-axis direction.

[0092] See in some examples Figure 6 The first rotating mechanism 131 may include a first rotating shaft 1311, a first rotating base 1313, and at least one first support arm 1312 disposed on the first rotating base 1313. In some examples, the measuring host 11 may be disposed on the first support arm 1312. In some examples, the first rotating mechanism 131 may include two first support arms 1312, and the measuring host 11 may be disposed between the first support arms 1312.

[0093] In some examples, the first rotating mechanism 131 may include a first angle encoder, a first drive motor that drives the first rotating shaft 1311 to rotate, and a first drive card that controls the first drive motor.

[0094] In some examples, the first rotating mechanism 131 can control the measurement host 11 to rotate along a first direction D1, thereby causing the laser emitting unit 12 located within the measurement host 11 to rotate along the first direction D1. In some examples, the first rotating chassis 1313 can be disposed on the first rotating shaft 1311, which can be disposed on the base 16 of the laser tracker 1 via a first bearing (see...). Figure 2 In this case, the first rotating mechanism 131 can drive the first rotating shaft 1311 to rotate and drive the first rotating base 1313 disposed on the first rotating shaft 1311 to rotate along the first direction D1, thereby driving the measuring host 11 disposed on the first support arm 1312 to rotate along the first direction D1, thereby driving the laser emitting unit 12 located on the measuring host 11 to rotate along the first direction D1.

[0095] In some examples, the second rotating mechanism 132 may be disposed on the first support arm 1312 of the first rotating mechanism 131 and may measure the rotation of the host 11 along the second direction D2.

[0096] In some examples, the second rotating mechanism 132 can be linked with the measuring host 11. In this case, the second rotating mechanism 132 can be used to drive the laser emitting unit 12 located on the measuring host 11 to rotate along the second direction D2. In some examples, the second rotating mechanism 132 may include a second rotating shaft 1321 connecting the measuring host 11 and a second bearing that mounts the second rotating shaft 1321 to the first support arm 1312. In this case, the second rotating shaft 1321 can be used to drive the measuring host 11 to rotate along the second direction D2, and thus the second rotating mechanism 132 can be used to drive the laser emitting unit 12 located on the measuring host 11 to rotate along the second direction D2.

[0097] In some examples, the second rotation mechanism 132 may include a second angle encoder, a second drive motor that drives the second rotation shaft 1321 to rotate, and a second drive card that controls the second drive motor.

[0098] In some examples, the first rotating shaft 1311 and the second rotating shaft 1321 may be precision shafts, and the first bearing and the second bearing that match the first rotating shaft 1311 and the second rotating shaft 1321 may be precision bearings.

[0099] In some examples, the first tracking control unit 13 can be configured to control the attitude of the laser emitting unit 12 based on the sensing information acquired by the first position sensing unit 116, so that the laser emitting unit 12 is aligned with the target 21. Specifically, in the first position sensing unit 116, if the first light spot is far away from the first preset zero point, it can be considered that the laser emitting unit 12 is not aligned with the target 21, and then the attitude adjustment method of the laser emitting unit 12 can be calculated based on the relative position between the first light spot and the first preset zero point. In this case, the first tracking control unit 13 can control the laser emitting unit 12 to track the target 21 based on the calculation result of the attitude adjustment method. At the same time, since the first position sensing unit 116 has high precision, it can achieve precise aiming of the six-dimensional laser tracking measurement system.

[0100] In some examples, the first tracking control unit 13 is configured to control the attitude of the laser emitting unit 12 based on the diverging beam acquired by the target acquisition unit 15, so that the laser emitting unit 12 is aligned with the target 21. Specifically, the emitting unit 14 (described later) can emit a diverging beam. After the target 21 reflects the diverging beam, the target acquisition unit 15 can receive the diverging beam reflected by the target 21 and preliminarily determine whether the laser emitting unit 12 is aligned with the target 21 based on the position of the centroid of the spot of the diverging beam reflected by the target 21, that is, the laser tracker 1 preliminarily captures the target 21. In this case, it is possible to quickly determine whether the laser emitting unit 12 has captured the target 21, and thus it is possible to quickly control the direction of the laser beam emitted by the laser emitting unit 12 so that the laser beam gradually approaches the target 21.

[0101] In some examples, the first tracking control unit 13 may also be any person or object capable of changing the orientation of the laser emitting unit 12. Specifically, the orientation of the laser emitting unit 12 may be changed automatically or manually.

[0102] In some examples, the laser tracker 1 may include a light-emitting unit 14 (see Figure 4 The light-emitting unit 14 can be configured to emit a diverging beam. In this case, since the light-emitting unit 14 can emit a diverging beam, even if the laser emitting unit 12 is not aligned with the target 21, the target 21 can still receive and reflect the diverging beam. Therefore, the position information of the target 21 can be quickly obtained based on the diverging beam reflected by the target 21, and the direction of the laser beam emitted by the laser emitting unit 12 can be quickly controlled so that the laser beam gradually approaches the target 21.

[0103] In some examples, the light-emitting unit 14 can also be set independently of the laser tracker 1.

[0104] In some examples, the light-emitting unit 14 can be linked with the laser emitting unit 12; in other words, when the laser emitting unit 12 rotates, the light-emitting unit 14 can also perform the same movement. In this case, the rotation mode of the laser emitting unit 12 can be determined by cooperating with the light-emitting unit 14 and the laser emitting unit 12.

[0105] See in some examples Figure 4 The light-emitting unit 14 and the window 115 can be disposed on the same side. In this case, the illumination range of the diverging beam emitted by the light-emitting unit 14 can be wider.

[0106] In some examples, the emitting unit 14 can cooperate with the target acquisition unit 15 for preliminary acquisition in a six-dimensional laser tracking measurement system. Preliminary acquisition may refer to the laser beam emitted by the laser emitting unit 12 approaching and aligning (or being emitted onto) the target 21. In some examples, preliminary acquisition may also refer to the laser emitting unit 12 gradually aligning with the target 21 so that the first position sensing unit 116 can receive the laser beam reflected by the target 21. In some examples, preliminary acquisition may also be referred to as coarse aiming. Compared to fine aiming, the accuracy of preliminary acquisition is limited by the focusing capability of the target acquisition unit 15. For example, when the distance between the target 21 and the laser tracker 1 exceeds a certain range (e.g., the distance between the target 21 and the laser tracker 1 is too far for the target acquisition unit 15 to focus), the positional accuracy of the spot formed by the diverging beam received by the target acquisition unit 15 may decrease. Therefore, the alignment accuracy of preliminary acquisition is lower than that of fine aiming. Meanwhile, compared to fine aiming, since the emitting unit 14 emits a divergent beam during the initial acquisition process, the target 21 can easily receive the divergent beam. That is, the target acquisition unit 15 can easily receive the divergent beam reflected by the target 21, thus enabling initial acquisition at any time. In this case, the laser emitting unit 12 can be aligned with the target 21 by combining the relatively low-precision but relatively relaxed initial acquisition with the relatively high-precision but more demanding fine aiming, thereby improving the tracking speed of the laser emitting unit 12 and also improving the measurement accuracy.

[0107] See in some examples Figure 4 The laser tracker 1 may include at least one light-emitting unit 14. In some examples, multiple light-emitting units 14 may be arranged around the target acquisition unit 15 on the outer surface of the housing of the measuring host 11. In some examples, the multiple light-emitting units 14 may be equidistant from the target acquisition unit 15; for example, the multiple light-emitting units 14 may be arranged symmetrically about the center of the target acquisition unit 15 on the outer surface of the housing. Preferably, the multiple light-emitting units 14 may be arranged in a cross-symmetric manner around the target acquisition unit 15. In this case, compared to calculating the attitude adjustment of the laser emitting unit 12 using the position of the centroid of the light spot formed by a single light-emitting unit 14, calculating the attitude adjustment of the laser emitting unit 12 using the position of the centroid of the light spots formed by multiple light-emitting units 14 can improve the accuracy of the calculation.

[0108] In some examples, multiple divergent beams emitted by multiple light-emitting units 14 are reflected by the target 21 and received by the target acquisition unit 15, and can be focused into a light spot with a regular shape in the target acquisition unit 15. For example, the divergent beams of light-emitting units 14 distributed in a ring around the target acquisition unit 15 can form a ring surrounded by multiple light spots in the target acquisition unit 15 after being reflected by the target 21.

[0109] In some examples, the light-emitting unit 14 can be an LED light. In some examples, the light-emitting unit 14 can also be any instrument or device capable of forming a diverging beam.

[0110] In some examples, the laser tracker 1 may include a light-emitting unit 14 and a target acquisition unit 15. The light-emitting unit 14 may be configured to emit a diverging beam, and the target acquisition unit 15 may be configured to receive the diverging beam reflected by the probe 2. In this case, through the diverging beam emitted by the light-emitting unit 14, the target acquisition unit 15 can quickly obtain the diverging beam reflected by the target 21 containing the position information of the target 21, thereby determining the initial position of the target 21. The first tracking control unit 13 controls the attitude of the laser emitting unit 12 to bring the laser beam emitted by the laser emitting unit 12 closer to the target 21 and achieve initial acquisition.

[0111] See in some examples Figure 5a , Figure 5b and Figure 5c The target acquisition unit 15 can be disposed on the surface of the housing. In some examples, the target acquisition unit 15 can also be disposed in the cavity formed by the housing, and the housing can be provided with a light-transmitting aperture or lens assembly 118 that allows the diverging beam reflected by the target 21 to pass through.

[0112] See in some examples Figure 5c The laser tracker 1 may include multiple target acquisition units 15. In this case, initial acquisition can be achieved using the multiple target acquisition units 15, and the rotation angle of the laser beam emitted by the laser emitting unit 12 can be calculated using the information acquired by the multiple target acquisition units 15, thereby improving the control accuracy of the initial acquisition. In some examples, the multiple target acquisition units 15 may be arranged around the window 115. In some examples, the multiple target acquisition units 15 may be centrally symmetrical about the window 115.

[0113] In some examples, the target acquisition unit 15 may be a CMOS photosensitive element, such as a CMOS image sensor. In other examples, the light-emitting unit 14 may be a CCD photosensitive element. However, this disclosure is not limited thereto, and the target acquisition unit 15 may also be other elements used for photosensitive imaging.

[0114] In some examples, the target acquisition unit 15 may include a photosensitive array (or pixel array). The photosensitive array may consist of multiple pixels and can convert the received light signal into an electrical signal output. In this case, data on the target acquisition spot formed on the target acquisition unit 15 by the diverging beam reflected by the target 21 can be obtained, and the spatial position of the target 21 (probe 2) can be roughly obtained based on the target acquisition spot.

[0115] In some examples, the spot formed by the diverging beam on the photosensitive array of the target acquisition unit 15 can be called the target acquisition spot. The attitude adjustment method of the laser emitting unit 12 is calculated based on the relative position between the target acquisition spot and the target acquisition null point. The target acquisition null point can be located at the position of the target acquisition spot formed by each light-emitting unit 14 when the laser emitting unit 12 is aligned with the target 21. The relative position between the target acquisition spot and the target acquisition null point can refer to the position of the target acquisition spot relative to the target acquisition null point.

[0116] See in some examples Figure 5a The lens assembly 118 can be positioned in front of the photosensitive array. In this case, the diverging light beam reflected by the target 21 can pass through the lens assembly 118 and form a target acquisition spot on the target acquisition unit 15. After being focused by the lens assembly 118, a clear target acquisition spot can be formed on the target acquisition unit 15. In some examples, see... Figure 5a The direction of the optical axis of the lens assembly 118 can be the same as the direction in which the laser beam is emitted from the measuring host 11.

[0117] In some examples, the lens assembly 118 may be a single lens. In other examples, the lens assembly 118 includes multiple lenses, the optical axes of which may be kept in the same straight line, and the foremost lens among the multiple lenses may be a condenser lens for focusing the light beam. In this case, the lens assembly 118 can easily focus the diverging light beam reflected by the target 21, thereby forming a clear light spot on the target acquisition unit 15.

[0118] In some examples, the laser tracker 1 may include a tracking head angle measurement unit, which may be configured to measure the rotation angle of the laser emitting unit 12 under the control of the first tracking control unit 13. In this case, the rotation angle of the laser emitting unit 12 can be obtained, and the spatial position of the target 21 can be calculated based on the rotation angle of the laser emitting unit 12 and the distance between the laser emitting unit 12 and the target 21.

[0119] In some examples, the tracking head angle measurement unit may include a first tracking head angle measurement unit configured to measure the rotation angle of the laser emitting unit 12 along a first direction D1. In some examples, the tracking head angle measurement unit may also include a second tracking head angle measurement unit configured to measure the rotation angle of the laser emitting unit 12 along a second direction D2. In this case, the rotation angles of the laser emitting unit 12 along the first direction D1 and the second direction D2 can be obtained, and the orientation of the target 21 in the laser tracker device coordinate system can be calculated based on the rotation angles of the laser emitting unit 12 along the first direction D1 and the second direction D2. Combined with the distance of the target 21 obtained by the distance measurement module (e.g., absolute ranging module 113 and / or interferometric ranging module 114), the specific position coordinates of the target 21 in the laser tracker device coordinate system can be calculated.

[0120] In some examples, the attitude of the laser emitting unit 12 can change synchronously with the direction vector of the laser beam. At the same time, the rotation angle of the laser emitting unit 12 along the first direction D1 and the rotation angle of the laser emitting unit 12 along the second direction D2 can represent the attitude of the laser emitting unit 12. Thus, the direction vector of the laser beam in the coordinate system of the laser tracker device can be represented by the rotation angle of the laser emitting unit 12 along the first direction D1 and the rotation angle of the laser emitting unit 12 along the second direction D2. In this way, the attitude of the target can be obtained in subsequent processes based on the direction vector of the laser beam in different coordinate systems and the transformation relationship between different coordinate systems.

[0121] In some examples, the tracking head angle measuring unit includes an optical grating disk and a reading head disposed on the rotation axis. For example, the first tracking head angle measuring unit may include a first tracking head optical grating disk disposed on the first rotation axis 1311 and a first tracking head reading head that obtains the rotation angle of the laser emitting unit 12 along the first direction D1 based on the first tracking head optical grating disk. The second tracking head angle measuring unit may include a second tracking head optical grating disk disposed on the second rotation axis 1321 and a second tracking head reading head that obtains the rotation angle of the laser emitting unit 12 along the second direction D2 based on the second tracking head optical grating disk. In this case, the rotation angle of the first rotation axis 1311 or the second rotation axis 1321 can be measured by the tracking head angle measuring unit to obtain the rotation angle of the laser emitting unit 12 rotating in the first direction D1 or the second direction D2. However, this disclosure is not limited to this, and the tracking head angle measuring unit may also be an instrument based on other measurement principles and capable of measuring the rotation angle of the laser emitting unit 12.

[0122] In some examples, the laser tracker 1 may include a first gravity alignment unit. In some examples, the first gravity alignment unit may be configured to align first direction information acquired by the tracking head angle measurement unit to the target coordinate system. In some examples, the first direction information may include the rotation angle of the laser emitting unit 12 along the first direction D1 and the rotation angle along the second direction D2. In some examples, the first gravity alignment unit may use the tilt angle of the laser tracker 1, the measuring host 11, the laser emitting unit 12, or the first plane S1 relative to the horizontal plane as the first tilt angle. In other words, the first gravity alignment unit may be configured to acquire the first tilt angle, and the first tilt angle may be configured to align the first direction information acquired by the tracking head angle measurement unit to the target coordinate system. Alignment may refer to calculating the representation of a vector in one coordinate system in another coordinate system through coordinate transformation.

[0123] In this case, since the rotation angles of the laser emitting unit 12 along the first direction D1 and the second direction D2 measured by the tracking head angle measurement unit can obtain the specific position coordinates of the target 21 in the laser tracker equipment coordinate system, and aligning the first direction information to the target coordinate system can obtain the orientation of the target 21 in the target coordinate system, the specific position coordinates of the target 21 in the target coordinate system can be calculated. At the same time, the second direction information obtained by the probe angle measurement unit can also be associated with the target coordinate system using the second tilt angle. That is, the second direction information obtained by the probe angle measurement unit can be transformed from the target coordinate system to the target coordinate system or the second direction information obtained by the probe angle measurement unit can be transformed from the target coordinate system to the target coordinate system using the transformation relationship between the target coordinate system and the target coordinate system. This allows the processing of the first direction information acquired by the tracking head angle measurement unit and the second direction information acquired by the probe angle measurement unit in the same coordinate system. This enables the association between the first direction information acquired by the laser tracker 1 and the second direction information acquired by the probe 2, and further enables the calculation of at least one of the three Euler angles of the probe 2 (or the target) based on the association between the first direction information acquired by the laser tracker 1 and the second direction information acquired by the probe 2.

[0124] In some examples, the target coordinate system can be a coordinate system established based on the direction of gravity. For instance, in the orthogonal axes of the target coordinate system, the Z-axis can be parallel to the direction of gravity, and the X and Y axes can be perpendicular to the direction of gravity, respectively. In this case, the spatial positions of various coordinate systems (e.g., the laser tracker equipment coordinate system and the target coordinate system) and gravity can be aligned to the target coordinate system. In practice, the yaw angle of the target needs to be calculated using the coordinates of the laser beam direction vector in different coordinate systems and the transformation relationship between the coordinates of different coordinate systems. At the same time, it is difficult to directly obtain the transformation relationship between the laser tracker equipment coordinate system and the target coordinate system. By aligning the first direction information to the target coordinate system and using the second tilt angle to represent the transformation relationship between the target coordinate system and the target coordinate system, an equation about the laser beam direction vector can be established, and the yaw angle can then be solved using the equation.

[0125] In some examples, aligning the first direction information to the target coordinate system can also be referred to as gravity alignment of the first direction information.

[0126] In some examples, the first gravity alignment unit may include two single-axis accelerometers, and the sensitive axes of the two single-axis accelerometers may be orthogonal. However, this disclosure is not limited to this; in some examples, the first gravity alignment unit may also include a dual-axis accelerometer. In some examples, the first gravity alignment unit may also include a triaxial accelerometer. In some examples, the first gravity alignment unit may also include two single-axis inclinometers or a dual-axis inclinometer (tilt sensor). In some examples, the first gravity alignment unit may also include a level. In some examples, the first gravity alignment unit may include any device capable of measuring the tilt angle of the laser tracker 1, the measuring host 11, the laser emitting unit 12, or the first plane S1 relative to the horizontal plane. In this case, two first tilt angles can be obtained, and then the transformation formula between the laser tracker device coordinate system and the target coordinate system can be obtained using the first tilt angles.

[0127] In some examples, the accelerometer can be a closed-loop liquid-floated pendulum, a flexible pendulum, a vibrating wire, or a pendulum integrating gyroscope. In some examples, the tilt sensor can be a solid pendulum, a liquid pendulum, or a gas pendulum. In some examples, the accelerometer can also be a MEMS accelerometer. In some examples, the accelerometer can also be a capacitive pendulum sensor.

[0128] In some examples, the first gravity alignment unit may include two single-axis accelerometers with orthogonal sensing axes. For instance, the first gravity alignment unit may include single-axis accelerometer a and single-axis accelerometer b. The sensing axes of single-axis accelerometer a and b may lie in the same plane. The plane containing the sensing axes of single-axis accelerometer a and b may be perpendicular to the first rotation axis 1311. The sensing axis of single-axis accelerometer a may be parallel to the second rotation axis 1321, and the sensing axis of single-axis accelerometer b may be perpendicular to the second rotation axis 1321. In this case, since the sensing axes of the first gravity alignment unit match the rotation axis of the first tracking control unit 13, the transformation formula between the laser tracker's coordinate system and the target coordinate system can be simplified, improving calculation speed and measurement accuracy. However, this disclosure is not limited to this. In other examples, the positional relationship between the sensing axes of the two single-axis accelerometers and the second rotation axis 1321 may not be parallel or perpendicular.

[0129] In some examples, the first tilt angle can be decomposed into a first tilt angle a and a first tilt angle b. In some examples, the first tilt angle a can be obtained by a single-axis accelerometer a, and the first tilt angle b can be obtained by a single-axis accelerometer b. In some examples, the first tilt angle a and the first tilt angle b can also be obtained by a dual-axis accelerometer. In some examples, the first tilt angle a and the first tilt angle b can also be obtained by a monolithically integrated triaxial accelerometer, wherein the two sensing axes of the triaxial accelerometer can be parallel and perpendicular to the second rotation axis 1321, respectively.

[0130] In some examples, the first gravity alignment unit can acquire the first tilt angle in real time. In other words, when calculating the six-dimensional coordinates of the target using a six-dimensional laser tracking measurement system, the first gravity alignment unit can continuously measure the first tilt angle. In this case, the first tilt angle can be acquired in real time, and the first tilt angle can be used in real time to perform gravity alignment on the first direction information acquired by the tracking head angle measurement unit, thereby enabling the real-time acquisition of the six-dimensional coordinates of probe 2 (or target).

[0131] In some examples, the first tilt angle can be used to perform gravity alignment of the first direction information. Specifically, the transformation formula between the laser tracker device coordinate system and the target coordinate system can be obtained using the first tilt angle, and the value of the first direction information in the laser tracker device coordinate system in the target coordinate system can be calculated using the transformation formula between the laser tracker device coordinate system and the target coordinate system.

[0132] In some examples, the first gravity alignment unit may be located within the first rotation mechanism 131. In some examples, the first gravity alignment unit may be located at other locations on the laser tracker 1, such as at the bottom of the measuring host 11 or other locations.

[0133] See in some examples Figure 2 and Figure 3 The laser tracker 1 may also include a bracket 17, which can be configured to support a base 16. In some examples, the base 16 may be detachably mounted on the bracket 17. In this case, it facilitates the connection between the base 16 and the first tracking control unit 13 and the measurement host 11 located on the base 16.

[0134] In some examples, bracket 17 may have shock-absorbing capabilities. In this case, measurement accuracy can be improved.

[0135] In some examples, the bracket 17 may include pulleys 171. In this case, it facilitates the movement of the laser tracker 1.

[0136] In some examples, the bracket 17 may include a set screw. In this case, the laser tracker 1 can be fixed to the ground.

[0137] The structure of probe 2 is further described below. As mentioned above, the six-dimensional laser tracking measurement system may include probe 2, which works in conjunction with laser tracker 1 to obtain the position and orientation of the target.

[0138] In some examples, probe 2 may also be referred to as an auxiliary measuring device, receiver, reflector, or target sphere. In some examples, probe 2 may be any device capable of reflecting a light beam in a manner opposite to the incident direction.

[0139] Figure 8 This is a schematic diagram showing probe 2 of the six-dimensional laser tracking measurement system involved in the example of this disclosure. Figure 9 This is a schematic diagram showing the third plane S3, the third direction D3, the axis A3 of the third rotation axis 2311, the fourth plane S4, the fourth direction D4, and the axis A4 of the fourth rotation axis 2321 involved in the example of this disclosure. Figure 10 The probe 2 of the six-dimensional laser tracking measurement system involved in this disclosure example is shown in... Figure 8 A cross-sectional view of the M-M' position. Figure 11 This illustrates the target 21 and the fourth rotation axis 2321 of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 8 A cross-sectional view of the N-N' position in the diagram. Figure 12 This is a front view showing a portion of the structure of the probe 2 of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 13This illustrates a partial structure of probe 2 of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 12 A cross-sectional view of the O-O' position in the diagram. Figure 14 This illustrates a partial structure of the target 21 of the six-dimensional laser tracking measurement system involved in this disclosure example. Figure 12 A cross-sectional view of the O-O' position in the diagram. Figure 15 This is a bottom view showing a portion of the structure of the probe 2 of the six-dimensional laser tracking measurement system involved in this disclosure example.

[0140] See in some examples Figure 8 , Figure 9 , Figure 10 , Figure 12 and Figure 13 The probe 2 may include a target 21 and a mounting base 22. In some examples, the target 21 may be used to reflect a light beam, and the mounting base 22 may be configured to mount the probe 2 to the target. In this case, the probe 2 can be fixed to the target by the mounting base 22, making the probe 2 linked to the target. This allows the position and orientation of the target 21 to be determined based on the light beam reflected by the target 21 (including laser beams and diverging beams), and the position of the mounting base 22 (i.e., the position and orientation of the target) can be determined based on the position and orientation of the target 21.

[0141] In some examples, target 21 can be configured to reflect a laser beam or a diverging beam.

[0142] In some examples, target 21 may have a through-hole 2122 (see Figure 11 In some examples, the via 2122 can be configured to detect whether the laser beam emitted by the laser emitting unit 12 is emitted to the second position sensing unit 2131 of the target 21 (see [link]). Figure 11 ).

[0143] See in some examples Figure 8 , Figure 9 and Figure 10 The structure of target 21 can be a symmetrical structure, for example, it can be about Figure 9 The fourth plane S4 in the diagram is symmetric.

[0144] In some examples, target 21 may have a multi-layered structure. For example, target 21 may include a three-layered structure. Specifically, target 21 may include a prism layer 211, an intermediate layer 212, and a reference layer 213 (see [link to documentation]). Figure 14 In some examples, the intermediate layer 212 may be disposed between the prism layer 211 and the reference layer 213. In some examples, the target 21 may include the prism layer 211, the intermediate layer 212, and the reference layer 213 disposed from front to back.

[0145] See in some examples Figure 14 The prism layer 211 can be provided with a notched reflector 2111. For example, the notched reflector 2111 can be a solid pyramid prism, a hollow pyramid prism, or a hollow optical retroreflector. In this case, the laser beam can be returned to the laser tracker 1 in the opposite direction to the incident direction, thereby enabling the measurement of the distance from the mechanical zero point of the laser tracker 1 to the center of the pyramid, that is, the distance between the laser emitting unit 12 and the target 21. In some examples, the mechanical zero point can refer to the origin of the coordinate system of the laser tracker device, and the center of the pyramid can be the origin of the target coordinate system. In other words, the coordinate system of the laser tracker device can be established with the mechanical zero point as the origin, and the target coordinate system can be established with the center of the pyramid as the origin.

[0146] In some examples, the mechanical zero point can refer to the intersection of the first rotation axis 1311 and the second rotation axis 1321 (that is, the mechanical zero point can be the intersection of the horizontal rotation axis and the pitch rotation axis), which simplifies the calculation. However, this disclosure is not limited to this, and the mechanical zero point can also be any position.

[0147] In some examples, the center of the pyramid can refer to the vertex V of the reflector 2111 with the notch. For example, vertex V can refer to... Figure 14 The vertex V of the cornerstone prism. In some examples, the position coordinates of target 21 can refer to the position coordinates of the center of the cornerstone.

[0148] In some examples, the diameter of the cut can be around 1.0 to 2.0 mm (e.g., the diameter of the cut can be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2.0 mm), but this disclosure is not limited to this diameter of the cut. The diameter of the cut can also be less than 1.0 mm or greater than 2.0 mm, and the diameter of the cut can also have higher or lower precision.

[0149] See in some examples Figure 14 The notch plane Sc can be parallel to the incident plane Si. The notch plane Sc can refer to the cut surface that forms the notch, and the incident plane Si can refer to the plane on which the laser beam is incident on the reflector 2111 with the notch. In this case, at least a portion of the incident laser beam can be projected through the vertex V to the second position sensing unit 2131 behind it.

[0150] In some examples, the reflector 2111 with the notch can be a hollow corner prism. In this case, when the incident light beam (also referred to as the incident beam) enters the hollow corner prism, the reflection of the incident light beam through the plane can reduce the refraction of the beam and thus reduce the loss of light energy, and can reduce the complexity of the optical path caused by refraction, thereby reducing the computational complexity.

[0151] In some examples, a hollow-corner pyramidal prism can be formed by three plane mirrors arranged perpendicularly in pairs. In this case, after the incident beam is reflected sequentially by the three plane mirrors, the direction of the outgoing light ray can be parallel to the direction of the incident beam. However, this disclosure is not limited to this; the hollow-corner pyramidal prism can also be any element capable of reflecting a beam in the opposite direction to the incident direction.

[0152] In some examples, the vertex V of the hollow pyramid prism can be located in the intermediate layer 212. In some examples, the body of the hollow pyramid prism can be located in the prism layer 211.

[0153] In some examples, the target 21 may include an intermediate layer 212 disposed behind the prism layer 211.

[0154] See in some examples Figure 14 The optical axis of the hollow corner prism can be made to be the optical axis Ao of the target 21. In some examples, the through hole 2122 can be located on the straight line where the optical axis Ao of the target 21 lies. In this case, when the laser beam emitted by the laser emitting unit 12 is incident along the optical axis of the hollow corner prism, that is, when the target 21 is aligned with the laser emitting unit 12, the laser beam can pass through the through hole 2122 and form a light spot at a specific position behind the through hole 2122 (e.g., the second preset zero point described later). Therefore, it is possible to determine whether the target 21 is aligned with the laser emitting unit 12 based on whether there is a light spot at the specific position behind the through hole 2122.

[0155] In some examples, a perforated plate 2121 may be provided in the intermediate layer 212 (see Figure 11 The through hole 2122 can be located on the perforated plate 2121. In some examples, the through hole 2122 located on the perforated plate 2121 can also be located at the vertex V of the reflector 2111 with a notch. In some examples, the through hole 2122 can be located on the perforated plate 2121 and on the straight line of the optical axis of the hollow corner prism, and the orientation of the through hole 2122 can be on the straight line of the optical axis of the hollow corner prism.

[0156] In some examples, the pinhole plate 2121 can be an aluminum plate with through holes 2122. However, this disclosure is not limited to this, and the constituent materials of the pinhole plate 2121 can also include metallic materials such as iron, copper, stainless steel, or tantalum, or non-metallic materials such as silicon, graphite, oxides, or carbides. In some examples, the pinhole plate 2121 can be a pinhole aperture.

[0157] In some examples, the shape of the through hole 2122 can be arbitrary, such as a polygon, an ellipse, or a circle. Preferably, the shape of the through hole 2122 can be circular.

[0158] In some examples, the size of the via 2122 can be smaller than the cross-sectional size of the laser beam. In this case, at least a portion of the laser beam can pass through the via 2122 and reach the reference layer 213 after the via 2122 to form a second spot.

[0159] See in some examples Figure 11 and Figure 13 The target 21 may include a filter 2123. In some examples, the filter 2123 may be disposed between the pinhole plate 2121 and the second position sensing unit 2131; in other words, the filter 2123 may be disposed behind the pinhole plate 2121. In this case, light outside a specific wavelength range (e.g., the wavelength of the laser beam formed by the laser emitting unit 12) can be filtered, so that the energy of the second light spot formed in the second position sensing unit 2131 through the through-hole 2122 comes from the laser beam formed by the laser emitting unit 12. This reduces the interference from ambient light or the light-emitting unit 14, thereby improving the detection accuracy of the laser beam orientation.

[0160] In some examples, the target 21 may include a reference layer 213 disposed behind the intermediate layer 212. In some examples, the reference layer 213 may be provided with a second position sensing unit 2131, which may be configured to receive a laser beam passing through the via 2122.

[0161] In some examples, the second position sensing unit 2131 may have a photosensitive surface. In some examples, the photosensitive surface of the second position sensing unit 2131 may be parallel to the notch plane Sc. In some examples, the photosensitive surface of the second position sensing unit 2131 may be parallel to the incident plane Si. In some examples, the photosensitive surface of the second position sensing unit 2131 may be perpendicular to the optical axis Ao of the target 21. In this case, since the photosensitive surface is perpendicular to the two axes of the target coordinate system, the attitude of the target 21 can be conveniently calculated using the position of the second light spot obtained by the second position sensing unit 2131, thereby simplifying the calculation. However, this disclosure is not limited to this; the photosensitive surface of the second position sensing unit 2131 may also not be parallel to the notch plane Sc.

[0162] In some examples, after the second position sensing unit 2131 receives the laser beam passing through the through hole 2122, it can determine whether the target 21 is aligned with the laser emitting unit 12 based on the second light spot formed by the laser beam on the photosensitive surface of the second position sensing unit 2131.

[0163] In some examples, the second position sensing unit 2131 can record the position of the second light spot on the photosensitive surface of the second position sensing unit 2131. In this case, the attitude of the target 21 and the attitude adjustment method of the target 21 can be calculated based on the position of the second light spot on the photosensitive surface of the second position sensing unit 2131. Compared with the prior art, which requires setting multiple light-emitting devices on the probe 2 and using the attitude camera and zoom lens set on the laser tracker 1 to obtain the position of the multiple light-emitting devices in space, and then calculating the attitude of the target 21 based on the position of the multiple light-emitting devices in space, the calculation of the attitude of the target 21 and the attitude adjustment method of the target 21 by the second position sensing unit 2131 does not require setting multiple light-emitting devices on the probe 2, nor does it require setting an attitude camera and zoom lens on the laser tracker 1. This can effectively reduce manufacturing and design costs, and also avoid the situation where the attitude camera and zoom lens are difficult to focus due to the target 21 being too far away, resulting in low accuracy of the target 21 attitude measurement. Compared to existing technologies that directly calculate the attitude of probe 2 (or target) using the position of the light spot on a position sensing unit (such as a PSD or CCD camera) located on probe 2, the calculated attitude of probe 2 (or target) is easily affected by the nonlinearity and drift error of the position sensing unit, leading to unstable target measurement accuracy. However, by using the second position sensing unit 2131 to acquire the attitude of target 21 and its attitude adjustment method, and aligning target 21 with the laser emitting unit 12, the second light spot formed by the laser beam is continuously located at a fixed point or servo zero point (i.e., the second preset zero point) in the second position sensing unit 2131. Then, by using components such as the probe angle measurement unit and the second gravity alignment unit 26 to calculate the attitude of probe 2 (or target) (described later), the influence of the nonlinearity and drift error of the position sensing unit on the accuracy of the probe 2 (or target) attitude can be effectively reduced, thereby improving the accuracy of target attitude measurement.

[0164] In some examples, the attitude adjustment method of the target 21 can be determined based on the relative position between the second light spot and the second preset zero point of the second position sensing unit 2131. The second preset zero point can be located at the position of the second light spot when the target 21 is aligned with the laser emitting unit 12.

[0165] In some examples, the second position sensing unit 2131 can acquire the position of the second light spot in real time. In other words, after the second position sensing unit 2131 forms the second light spot, it can continuously acquire the position of the second light spot. In this case, the attitude of the target 21 can be continuously determined, and the attitude adjustment method of the target 21 can be determined in real time. Based on the attitude adjustment method of the target 21, the second tracking control unit can be controlled to make the target 21 aligned with the laser emitting unit 12 in real time.

[0166] In some examples, the second position sensing unit 2131 may be a position sensor (PSD) or a CCD (charge coupled device) camera.

[0167] In some examples, when the hollow corner prism does not receive a laser beam, it can be assumed that the laser tracker 1 is not aligned with the target 21; when the hollow corner prism receives a laser beam, and the reflected laser beam forms a spot at the first preset zero point in the first position sensing unit 116, it can be assumed that the laser tracker 1 is aligned with the target 21; when the hollow corner prism receives a laser beam, and at least a portion of the laser beam passes through the through-hole 2122 and forms a spot in the second position sensing unit 2131, and at least a portion of the laser beam forms a spot in the second position sensing unit 2131, it can be assumed that the laser tracker 1 is aligned with the target 21. If the light spot formed by the laser beam 1 is not located at the second preset zero point, it can be considered that the laser beam is not parallel to the optical axis Ao of the target 21, and the target 21 is not aligned with the laser tracker 1. When the hollow corner cone prism receives the laser beam, and at least a portion of the laser beam passes through the through hole 2122 and forms a light spot in the second position sensing unit 2131, and the light spot formed by at least a portion of the laser beam in the second position sensing unit 2131 is located at the second preset zero point, it can be considered that the laser beam is parallel to the optical axis Ao of the target 21, and the target 21 is aligned with the laser tracker 1. In this case, it is possible to determine which stage the six-dimensional laser tracking measurement system is in based on the relationship between the laser beam and the probe 2.

[0168] In some examples, the surface of the target 21 may not be provided with a light-emitting device for acquiring the attitude of the target 21. In this case, the manufacturing and design costs of the target 21 can be effectively reduced, and the attitude camera and zoom lens for receiving the light beam from the light-emitting device of the target 21 do not need to be provided in the laser tracker 1, further reducing the manufacturing and design costs of the laser tracker 1.

[0169] See in some examples Figure 8 The probe 2 may include a second tracking control unit, which may be configured to control the attitude of the target 21 based on sensing information acquired by the second position sensing unit 2131 so that the target 21 is aligned with the laser emitting unit 12. In this case, the target 21 can be driven by the second tracking control unit to align the target 21 with the laser emitting unit 12.

[0170] In some examples, the second tracking control unit may include a third rotation mechanism 231 that controls the target 21 to rotate along a third direction D3 (see [reference]). Figure 8 In this case, the target 21 can be controlled to rotate along the third direction D3 using the third rotation mechanism 231 to track the laser tracker 1 in the third direction D3.

[0171] In some examples, the second tracking control unit may include a fourth rotation mechanism 232 that controls the target 21 to rotate along the fourth direction D4 (see [reference]). Figure 10 In this case, the target 21 can be controlled to rotate along the fourth direction D4 using the fourth rotation mechanism 232 to track the laser tracker 1 in the fourth direction D4.

[0172] In some examples, combined Figure 9 and Figure 10 The rotation of target 21 along the third direction D3 can mean that target 21 rotates within the third plane S3, which is perpendicular to the third rotation axis 2311. In this case, target 21 can rotate around the third rotation axis 2311.

[0173] In some examples, when the probe 2 is mounted on the target, the surface on the target used for mounting the fixed base 22 is designated as the mounting surface, and the third plane S3 can be parallel to the mounting surface. In other words, the third plane S3 is associated with the surface on the target used for mounting the fixed base 22 as the mounting surface. When the target's attitude changes, the third plane S3 may also change. When the target 21 rotates along the third direction D3, the third rotation axis 2311 can be perpendicular to the mounting surface. However, this disclosure is not limited to this. In some examples, when the third rotation mechanism 231 drives the target 21 to rotate, the target 21 can also rotate in any plane, that is, when the target 21 rotates along the third direction D3, the third rotation axis 2311 of the third rotation mechanism 231 can be in any direction.

[0174] In some examples, combined Figure 9 and Figure 10 The rotation of target 21 along the fourth direction D4 can mean that target 21 can rotate within the fourth plane S4. The fourth plane S4 does not coincide with or parallel to the third plane S3, and the fourth plane S4 is perpendicular to the fourth rotation axis 2321. Target 21 can rotate around the fourth rotation axis 2321.

[0175] In some examples, the fourth plane S4 can be a plane perpendicular to the notch plane Sc (or the photosensitive surface of the second position sensing unit 2131). In other words, the fourth rotation axis 2321 can be parallel to the notch plane Sc (or the photosensitive surface of the second position sensing unit 2131). In some examples, when the probe 2 is mounted on the target, the surface on the target used for mounting the fixed base 22 is taken as the mounting surface, and the fourth plane S4 can be perpendicular to the mounting surface. In other words, the fourth plane S4 is associated with the surface on the target used for mounting the fixed base 22 as the mounting surface. When the target's attitude changes, the fourth plane S4 may also change. When the target 21 rotates along the fourth direction D4, the fourth rotation axis 2321 can be parallel to the mounting surface. However, this disclosure is not limited to this. In some examples, when the fourth rotation mechanism 232 drives the target 21 to rotate, the target 21 can also rotate in any plane. That is, when the target 21 rotates along the fourth direction D4, the fourth rotation axis 2321 of the fourth rotation mechanism 232 can be in any direction.

[0176] In some examples, the third rotation axis 2311 can be perpendicular to the fourth rotation axis 2321. In other words, the third plane S3 can be perpendicular to the fourth plane S4. In this case, the attitude adjustment of the target 21 can be conveniently decomposed into rotation along the third direction D3 and rotation along the fourth direction D4, thereby enabling the target 21 to be oriented in any direction using the third rotation mechanism 231 and the fourth rotation mechanism 232, that is, the optical axis Ao of the target 21 points in any direction.

[0177] In some examples, the axis A3 of the third rotation axis 2311 can intersect the axis A4 of the fourth rotation axis 2321, and the intersection point of the axis A3 of the third rotation axis 2311 and the axis A4 of the fourth rotation axis 2321 can be used as the origin of the target coordinate system. In this case, the calculation can be simplified, the calculation speed can be improved, and the accuracy of the calculation can be improved.

[0178] In some examples, the target coordinate system can be a coordinate system with the intersection of the axis A3 of the third rotation axis 2311 and the axis A4 of the fourth rotation axis 2321 as the origin, the direction of the axis A3 of the third rotation axis 2311 as the Z-axis direction, the direction of the axis A4 of the fourth rotation axis 2321 as the Y-axis direction, and the direction perpendicular to the axis A3 of the third rotation axis 2311 and the axis A4 of the fourth rotation axis 2321 as the X-axis direction.

[0179] In some examples, the axis A3 of the third rotation axis 2311 can intersect the axis A4 of the fourth rotation axis 2321, and the intersection point of the axis A3 of the third rotation axis 2311 and the axis A4 of the fourth rotation axis 2321 can be set at the vertex V of the reflector 2111 with the notch. In this case, the calculation can be simplified, the calculation speed can be improved, and the accuracy of the calculation can be improved.

[0180] See in some examples Figure 10 The third rotating mechanism 231 may include a third rotating shaft 2311, a third rotating chassis 2313, and at least one third support arm 2312 disposed on the third rotating chassis 2313. The target 21 may be disposed on the third support arm 2312. In some examples, the third rotating mechanism 231 may include two third support arms 2312, and the target 21 may be disposed between the two third support arms 2312.

[0181] In some examples, the third rotation mechanism 231 can be disposed on the fixed base 22. The third rotation mechanism 231 may include a third rotation shaft 2311, a third bearing 2314 that matches the third rotation shaft 2311, a third support arm 2312 that is linked to the third rotation shaft 2311, and a third drive motor 2315 that drives the third rotation shaft 2311 to rotate. In this case, the third drive motor 2315 can be used to drive the third rotation shaft 2311 to rotate, thereby driving the third support arm 2312 to rotate around the third rotation shaft 2311, and thus driving the target 21 to rotate around the third rotation shaft 2311.

[0182] In some examples, the third rotation mechanism 231 may include a third angle encoder, a third drive motor 2315, and a third drive card for controlling the third drive motor 2315.

[0183] In some examples, the third rotating mechanism 231 can control the target 21 to rotate along a third direction D3. In some examples, the third rotating chassis 2313 can be disposed on the third rotating shaft 2311, and the third rotating shaft 2311 can be disposed on the fixed base 22 via the third bearing 2314. In this case, the third rotating mechanism 231 can drive the third rotating shaft 2311 to rotate and drive the third rotating chassis 2313 disposed on the third rotating shaft 2311 to rotate along the third direction D3, thereby driving the target 21 disposed on the third support arm 2312 to rotate along the third direction D3.

[0184] In some examples, the fourth rotating mechanism 232 may be disposed on the third support arm 2312 of the third rotating mechanism 231 and be able to drive the fourth rotating shaft 2321 to rotate in the fourth direction D4.

[0185] In some examples, the fourth rotation axis 2321 can be linked with the target 21. In this case, the target 21 can be driven to rotate along the fourth direction D4 using the fourth rotation mechanism 232. In some examples, the fourth rotation mechanism 232 may include a fourth rotation axis 2321 that connects to the target 21 and positions the target 21 on the third support arm 2312, a fourth bearing 2322 that matches the fourth rotation axis 2321, a fourth angle encoder, a fourth drive motor 2323 that drives the fourth rotation axis 2321 to rotate, and a fourth drive card that controls the fourth drive motor 2323. In this case, the fourth rotating shaft 2321 is set on the third support arm 2312 by the fourth bearing 2322, so that the third support arm 2312 can drive the fourth rotating shaft 2321 and the target 21 set on the fourth rotating shaft 2321 to rotate around the third rotating shaft 2311. At the same time, the fourth rotating shaft 2321 can be driven to rotate by the fourth drive motor 2323, thereby driving the target 21 to rotate around the fourth rotating shaft 2321. Thus, the target 21 can be driven to rotate along the fourth direction D4 by the fourth rotating shaft 2321.

[0186] In some examples, the third rotating shaft 2311 and the fourth rotating shaft 2321 may be precision shafts, and the third bearing 2314 and the fourth bearing 2322 that are matched with the third rotating shaft 2311 and the fourth rotating shaft 2321 may be precision bearings.

[0187] In some examples, the second tracking control unit can be configured to control the attitude of the target 21 based on sensing information acquired by the second position sensing unit 2131 so that the target 21 is aligned with the laser emitting unit 12. Specifically, in the second position sensing unit 2131, if the second light spot is far from the second preset zero point, it can be considered that the target 21 is not aligned with the laser emitting unit 12, and the attitude adjustment method of the target 21 can be calculated based on the relative position between the second light spot and the second preset zero point. In this case, based on the calculation result of the attitude adjustment method, the second tracking control unit can control the target 21 to track the laser emitting unit 12 in the opposite direction, and the relative position between the second light spot and the second preset zero point can refer to the position of the second light spot relative to the second preset zero point.

[0188] In some examples, the second tracking control unit can be composed of a third rotating mechanism 231 and a fourth rotating mechanism 232. In this case, the target 21 can be controlled to rotate in two directions. The second tracking control unit composed of the third rotating mechanism 231 and the fourth rotating mechanism 232 can reduce manufacturing and design costs. At the same time, when the second tracking control unit is composed of the third rotating mechanism 231 and the fourth rotating mechanism 232, the target 21 can be aligned with the laser emitting unit 12, and the attitude of the target 21 can be obtained based on measurement and calculation.

[0189] In some examples, the second tracking control unit can also be any person or object capable of changing the orientation of the target 21. Specifically, the orientation of the target 21 can be changed automatically or manually.

[0190] See in some examples Figure 10 The probe 2 may include a probe angle measurement unit, which can be configured to measure the rotation angle of the target 21 under the control of the second tracking control unit. In this case, the rotation angle of the target 21 can be obtained using the probe angle measurement unit, thereby determining the positional relationship between the attitude of the target 21 and the attitude of the probe 2 based on the rotation angle of the target 21, and further obtaining the rotation angle of the target 21 relative to the probe 2, and then calculating the spatial attitude of the target based on the rotation angle of the probe 2. It should be noted that the process of controlling the rotation of the target 21 using the second tracking control unit is also the process of controlling the rotation of the target 21 relative to the fixed base 22. The attitude of the probe 2 can refer to the attitude of the fixed base 22 in the probe 2. Since the fixed base 22 is installed on the target, the movement of the fixed base 22 is synchronized with the movement of the target, so the attitude of the probe 2 can also refer to the attitude of the target. At the same time, since the target 21 is continuously aligned with the laser emitting unit 12 under the control of the second tracking control unit, the attitude of the target 21 can change synchronously with the direction vector of the laser beam. In other words, the rotation angle of the target 21 relative to the probe 2 is obtained, which is also the change of the direction vector of the laser beam relative to the target (that is, the direction vector of the laser beam in the target coordinate system).

[0191] In some examples, calculating the spatial attitude of the target based on the rotation angle of probe 2 can refer to first determining the direction vector of the laser beam in the target coordinate system based on the rotation angle of target 21, then determining the direction vector of the laser beam in the laser tracker equipment coordinate system based on the rotation angle of laser emitting unit 12, and using the direction vector of the laser beam in different coordinate systems (e.g., laser tracker equipment coordinate system, target coordinate system, and target coordinate system) and the transformation relationship between different coordinate systems to calculate the yaw angle of probe 2 (or target).

[0192] See in some examples Figure 10 The probe angle measurement unit may include a first probe angle measurement unit 24 configured to measure the rotation angle of the target 21 along the third direction D3 and a second probe angle measurement unit 25 configured to measure the rotation angle of the target 21 along the fourth direction D4. In this case, the rotation angles of the target 21 along the third direction D3 and the fourth direction D4 can be obtained, and the direction vector of the laser beam in the target coordinate system can be calculated based on the rotation angles of the target 21 along the third direction D3 and the fourth direction D4.

[0193] In some examples, the probe angle measuring unit includes an optical grating disk and a reading head disposed on the rotation axis. For example, the first probe angle measuring unit 24 may include a first probe optical grating disk 241 disposed on the third rotation axis 2311 and a first probe reading head 242 that obtains the rotation angle of the target 21 along the third third direction D3 based on the first probe optical grating disk 241. The second probe angle measuring unit 25 may include a second probe optical grating disk 251 disposed on the fourth rotation axis 2321 and a second probe reading head 252 that obtains the rotation angle of the target 21 along the fourth direction D4 based on the second probe optical grating disk 251. In this case, the rotation angle of the third rotation axis 2311 or the fourth rotation axis 2321 can be measured by the probe angle measuring unit to calculate the direction vector of the laser beam in the target coordinate system. However, this disclosure is not limited to this, and the probe angle measuring unit may also be an instrument based on other measurement principles and capable of measuring the rotation angle of the target 21.

[0194] See in some examples Figure 10 and Figure 13 The probe 2 may include a second gravity alignment unit 26.

[0195] In some examples, the second gravity alignment unit 26 can be configured to acquire the target's attitude; in some examples, the second gravity alignment unit 26 can be used to acquire at least one Euler angle of the target. In some examples, the second gravity alignment unit 26 can be used to acquire the target's pitch and roll angles.

[0196] In some examples, the second gravity alignment unit 26 may be configured to associate the second direction information acquired by the probe angle measurement unit with the target coordinate system (e.g., aligning the coordinates of the laser beam direction in the target coordinate system to the target coordinate system). The second direction information acquired by the probe angle measurement unit may include the rotation angle of the target 21 along the third direction D3 and the rotation angle along the fourth direction D4.

[0197] See in some examples Figure 10 , Figure 12 and Figure 13 The second gravity alignment unit 26 can be mounted on the fixed base 22. In this case, since the fixed base 22 is mounted on the target and remains relatively stationary, the second gravity alignment unit 26 can remain fixed relative to the target without rotating with the rotation of the target 21, thus enabling the measurement of the target's tilt angle. Furthermore, compared to the scheme where the second gravity alignment unit 26 is mounted on the target 21, i.e., the second gravity alignment unit 26 rotates under the drive of the third rotation mechanism 231 or the fourth rotation mechanism 232, the dynamic response requirements of the second gravity alignment unit 26 can be reduced, thereby improving the measurement accuracy of the second gravity alignment unit 26 and simplifying the calculation process.

[0198] In some examples, the second gravity alignment unit 26 can use the tilt angle of the fixed base 22 or the third plane S3 relative to the horizontal plane as the second tilt angle. In other words, the second gravity alignment unit 26 can be configured to acquire the second tilt angle of the probe 2, which can be configured to calculate the transformation relationship between the target coordinate system and the target coordinate system. In this case, the direction vector of the laser beam in the laser tracker device coordinate system and the direction vector of the laser beam in the target coordinate system can be correlated. At the same time, since most of the components of the probe 2, except for the rotatable target 21, remain relatively stationary with respect to the fixed base 22, the tilt angle of the fixed base 22 or the third plane S3 relative to the horizontal plane can also refer to the tilt angle of the probe 2 relative to the horizontal plane. Since the fixed base 22 is mounted on the target, the tilt angle of the fixed base 22 relative to the horizontal plane can also be the tilt angle of the target relative to the horizontal plane, such as the target's pitch angle and roll angle. Meanwhile, since the transformation relationship between the target coordinate system and the target coordinate system can be obtained using the Euler angles of the target (including pitch angle, roll angle and yaw angle), the yaw angle of the target can be calculated when the direction vector of the laser beam in the coordinate system of the laser tracker, the direction vector of the laser beam in the target coordinate system, the pitch angle of the target and the roll angle of the target are known.

[0199] See in some examples Figure 15 The second gravity alignment unit 26 may include two single-axis accelerometers, and the sensitive axes of the two single-axis accelerometers are orthogonal. However, this disclosure is not limited to this; in some examples, the second gravity alignment unit 26 may also include a triaxial accelerometer. In some examples, the second gravity alignment unit 26 may also include a biaxial accelerometer. In some examples, the second gravity alignment unit 26 may also include two single-axis inclinometers or a biaxial inclinometer (tilt sensor). In some examples, the second gravity alignment unit 26 may also include a level. In some examples, the second gravity alignment unit 26 may include any device capable of tilting the fixed base 22 or the third plane S3 relative to the horizontal plane. In this case, the transformation relationship between the target coordinate system and the objective coordinate system can be calculated by obtaining two second tilt angles.

[0200] In some examples, similar to the first gravity alignment unit, the accelerometer in the second gravity alignment unit 26 can be a closed-loop liquid-floating pendulum, a flexible pendulum, a vibrating wire, or a pendulum integrating gyroscope, etc., and the tilt sensor can be a solid pendulum, a liquid pendulum, or a gas pendulum, etc. In some examples, the accelerometer can also be a MEMS accelerometer. In some examples, the accelerometer can also be a capacitive pendulum sensor.

[0201] In some examples, assuming the second gravity alignment unit 26 includes two single-axis inclinometers with orthogonal sensing axes, the second gravity alignment unit 26 may include a first inclinometer 26a and a second inclinometer 26b (see [reference]). Figure 15 In this second gravity alignment unit 26, the sensitive axes of the first inclinometer 26a and the second inclinometer 26b can lie in the same plane. The plane containing the sensitive axes of the first inclinometer 26a and the second inclinometer 26b can be perpendicular to the third rotation axis 2311. The sensitive axis of the first inclinometer 26a can be parallel to the fourth rotation axis 2321, and the sensitive axis of the second inclinometer 26b can be perpendicular to the fourth rotation axis 2321. In other words, the second gravity alignment unit 26 can include the first inclinometer 26a and the second inclinometer 26b. The mounting direction of the first inclinometer 26a can be perpendicular to the extension direction of the rotation axis of the third rotation mechanism 231, and the mounting direction of the second inclinometer 26b can be parallel to the extension direction of the rotation axis of the fourth rotation mechanism 232. The mounting direction of the first inclinometer 26a can be perpendicular to the mounting direction of the second inclinometer 26b. In this configuration, since the sensitive axis of the second gravity alignment unit 26 matches the rotation axis of the second tracking control unit, the transformation formulas between the target coordinate system and the target coordinate system can be simplified, improving calculation speed and measurement accuracy. Simultaneously, the second tilt angle measured by the first inclinometer 26a can be used as the pitch angle of the fixed base 22 (or the target), and the second tilt angle measured by the second inclinometer 26b can be used as the roll angle of the fixed base 22 (or the target). However, this disclosure is not limited to this; in other embodiments, the positional relationship between the sensitive axes of the two single-axis inclinometers and the fourth rotation axis 2321 may not be parallel or perpendicular.

[0202] In some examples, the second tilt angle can be decomposed into a second tilt angle a and a second tilt angle b. In some examples, the second tilt angle a can be obtained using a first inclinometer 26a, and the second tilt angle b can be obtained using a second inclinometer 26b. In some examples, the second tilt angle a and the second tilt angle b can also be obtained using a dual-axis inclinometer. In some examples, the second tilt angle a and the second tilt angle b can also be obtained using a monolithically integrated triaxial inclinometer, wherein the two sensing axes of the triaxial inclinometer are parallel and perpendicular to the fourth rotation axis 2321, respectively.

[0203] In some examples, the second gravity alignment unit 26 can acquire the second tilt angle in real time. In other words, when calculating the six-dimensional coordinates of the target using a six-dimensional laser tracking measurement system, the second gravity alignment unit 26 can continuously measure the second tilt angle. In this case, the second tilt angle can be acquired in real time, and the Euler angles of the probe 2 can be obtained in real time using the second tilt angle.

[0204] In some examples, probe 2 may also include a gyroscope disposed on fixed base 22, which may be configured to improve the accuracy of the second tilt angle acquired by the second gravity alignment unit 26 under dynamic conditions. Since the movement of fixed base 22 (or target) introduces acceleration other than gravity into the second gravity alignment unit 26, which leads to a decrease in the accuracy of the second tilt angle, the use of a gyroscope can improve the dynamic measurement accuracy of the second tilt angle.

[0205] In some examples, probe 2 may also include two gyroscopes mounted orthogonally to each other. By introducing two orthogonal gyroscopes, the angular velocity in the direction of the sensitive axis of the first inclinometer 26a and the angular velocity in the direction of the sensitive axis of the second inclinometer 26b are measured respectively. In this case, since gyroscopes have high angular measurement accuracy in a short time and are suitable for measuring angular velocity under motion, the data measured by the second gravity alignment unit 26 and the data measured by the gyroscopes can be fused by using filtering algorithms such as Kalman filtering. This can complement the data measured by the second gravity alignment unit 26 and the data measured by the gyroscopes, thereby improving the measurement accuracy of the second tilt angle.

[0206] In some examples, probe 2 may not include a gyroscope, thereby reducing manufacturing costs. In other examples, the gyroscope may be an optional component of probe 2 and may be detachably mounted on the mounting base 22. In this case, it is possible to determine whether a gyroscope is required or installed based on the intended use.

[0207] See in some examples Figure 1 The six-dimensional laser tracking measurement system may include a data analyzer 3. In some examples, the data analyzer 3 may have built-in analysis software.

[0208] In some examples, the data analyzer 3 can be a portable data processor, such as a laptop, tablet, mobile phone, or portable dedicated terminal. This allows the data analyzer 3 to collect location information or perform calculations.

[0209] In some examples, the data analyzer 3 may also be integrated into the laser tracker 1 or the probe 2. In other examples, the data analyzer 3 may be partially integrated into the laser tracker 1 or the probe 2. In this case, data processing can be more convenient and the calculation speed can be improved.

[0210] In some examples, the data analyzer 3 can operate independently of the laser tracker 1 or the probe 2 and transmit data via wired or wireless communication.

[0211] In some examples, the laser tracker 1 can send the calculated six-dimensional coordinates of the target to the data analyzer 3. In other examples, the data analyzer 3 can also receive data acquired by the first gravity alignment unit, the tracking head angle measurement unit, the second gravity alignment unit 26, and the probe angle measurement unit, and calculate the six-dimensional coordinates of the target based on this data. In some examples, the data analyzer 3 can receive data acquired by the first position sensing unit 116 or the target acquisition unit 15, and calculate the attitude adjustment mode of the laser tracker 1 based on this data. In some examples, the data analyzer 3 can receive data acquired by the second position sensing unit 2131, and calculate the attitude adjustment mode of the target 21 based on this data.

[0212] This disclosure also relates to an attitude detection method based on reverse tracking, which enables reverse tracking of the probe 2 and obtains the Euler angles of the target.

[0213] This disclosure also relates to a 6D attitude detection method based on reverse tracking, which enables reverse tracking of the probe 2 and obtains the six-dimensional coordinates of the target.

[0214] In some examples, in 6D attitude detection methods based on backtracking, the six-dimensional coordinates of the target can be obtained using attitude detection methods based on backtracking.

[0215] In some examples, the 6D attitude detection method based on backtracking can also be called a multidimensional measurement method, a method for determining the orientation and position of a target, a target measurement method, or a 6D attitude detection measurement method.

[0216] Figure 16 This is a flowchart illustrating the 6D pose detection method involved in the example of this disclosure.

[0217] In some examples, the methods disclosed herein (including attitude detection methods and 6D attitude detection methods) can be applied to the 6D attitude detection device disclosed herein. In other words, the methods disclosed herein can be implemented using the 6D attitude detection device disclosed herein. However, this disclosure is not limited thereto, and the methods disclosed herein can also be applied to other devices capable of implementing these methods.

[0218] See in some examples Figure 16 The 6D attitude detection method may include obtaining the position coordinates of the target 21 (step S001); aligning the target 21 with the laser emitting unit 12 (step S003); and obtaining the Euler angles of the target (step S005). In this case, since the target 21 can be aligned with the laser emitting unit 12 to achieve reverse tracking, the Euler angles of the target can be calculated based on the rotation angle of the target 21.

[0219] In some examples, the attitude detection method may include steps S003 and S005.

[0220] In some examples, the target's position coordinates can be obtained in step S001. In some examples, the target's position coordinates can be obtained using the absolute ranging module 113 and the interferometric ranging module 114 described above. Specifically, the distance from the mechanical zero point of the laser tracker 1 to the center of the cone can be obtained using the absolute ranging module 113 and the interferometric ranging module 114, and then the target's position coordinates can be calculated based on the rotation angle of the laser tracker 1 obtained by the tracking head angle measurement unit.

[0221] In some examples, the laser emitting unit 12 can be aligned with the target 21 first, and then the position coordinates of the target 21 can be obtained.

[0222] In some examples, in the laser tracker 1, the laser emitting unit 12 can be controlled to rotate along a first direction D1 and a second direction D2 to change the direction of the laser beam emitted by the laser emitting unit 12, so that the laser emitting unit 12 is aligned with the target 21, and the laser beam reflecting from the target 21 carrying the position information of the target 21 is received. The position information of the target 21 is obtained based on the laser beam carrying the position information of the target 21 and the rotation angle of the laser emitting unit 12. In this case, by controlling the attitude of the laser emitting unit 12, the laser emitting unit 12 can be aligned with the target 21, the laser beam can be emitted to the target 21, and the laser beam reflected from the target 21 can be received. Then, the distance information of the target 21 (or target) can be calculated based on the laser beam carrying the position information of the target 21. At the same time, the orientation of the target 21 relative to the laser emitting unit 12 can be obtained based on the rotation angle of the laser emitting unit 12, and the position coordinates of the target 21 can be calculated.

[0223] In some examples, as described above, the laser emitting unit 12 can be aligned with the target 21 by initial capture and fine aiming.

[0224] In some examples, initial capture can be achieved by controlling the laser emitting unit 12 to rotate along a first direction D1 and a second direction D2 to bring the laser beam closer to the target 21 until the target 21 receives and reflects the laser beam emitted by the laser emitting unit 12. In some examples, initial capture can be achieved by using the light-emitting unit 14 and the target capture unit 15 in cooperation.

[0225] In some examples, fine aiming involves the laser tracker 1 receiving the laser beam reflected from the target 21 and controlling the laser emitting unit 12 to rotate along a first direction D1 and a second direction D2 so that the laser beam passes through a preset position on the target 21, which is the through-hole 2122 on the target 21. In some examples, fine aiming can be achieved using the first position sensing unit 116. In this case, the laser emitting unit 12 can be aligned with the target 21 using fine aiming, which has relatively high accuracy but stringent implementation conditions, thereby improving measurement accuracy.

[0226] In some examples, initial acquisition may include: emitting a diverging beam from a laser tracker 1; receiving the diverging beam reflected from a target 21 using a target acquisition unit 15 disposed on the laser tracker 1; calculating the attitude adjustment mode of the laser emitting unit 12 based on the target acquisition spot formed by the diverging beam reflected from the target 21 on the target acquisition unit 15; and controlling the laser emitting unit 12 to rotate along a first direction D1 and a second direction D2 to bring the laser beam closer to the target 21 until the target 21 receives and reflects the laser beam emitted by the laser emitting unit 12. In this case, because of the use of a diverging beam, even if the laser emitting unit 12 is not aligned with the target 21, the target 21 can still reflect the diverging beam, thereby enabling the rapid location of the target 21 and the rapid control of the direction of the laser beam emitted by the laser emitting unit 12 to gradually bring the laser beam closer to the target 21.

[0227] In some examples, precise aiming may include: receiving the laser beam reflected from the target 21 using a first position sensing unit 116 disposed on the laser tracker 1; calculating the attitude adjustment mode of the laser emitting unit 12 based on the first light spot formed by the laser beam reflected from the target 21 in the first position sensing unit 116; and controlling the laser emitting unit 12 to rotate along a first direction D1 and a second direction D2 so that the laser beam passes through a preset position on the target 21. In this case, since the first position sensing unit 116 receives the laser beam reflected from the target 21 and has high accuracy and sensitivity, it can control the laser emitting unit 12 to align with and track the target 21 in real time with high precision.

[0228] In some examples, other methods can also be used to obtain the target's position coordinates. For example, the 6D attitude detection device may include a positioning module capable of determining the position of target 21. The positioning module can record the movement of target 21 (or target) and calculate the position coordinates of target 21 (or target). In some examples, the positioning module can send the position of target 21 to laser tracker 1 or data analyzer 3.

[0229] In some examples, the positioning module can be located on probe 2, or it can be set up independently of probe 2 and laser tracker 1.

[0230] In some examples, in step S003, the target 21 can be aligned with the laser emitting unit 12.

[0231] In some examples, the target 21 can be rotated in two directions within the probe 2 to align the target 21 with the laser emitting unit 12. In some examples, the two directions can be the third direction D3 and the fourth direction D4 as described above.

[0232] In some examples, a second position sensing unit 2131 disposed on the target 21 can be used to receive a laser beam passing through a preset position. Based on the second spot of the laser beam received by the target 21 in the second position sensing unit 2131, the attitude adjustment mode of the target 21 can be calculated, and the target 21 can be controlled to rotate along the third direction D3 and the fourth direction D4 so that the target 21 is aligned with the laser emitting unit 12. In this case, since the laser emitting unit 12 is already aligned with the target 21 when the laser beam passes through the preset position, aligning the target 21 with the laser emitting unit 12 can make the incident plane Si of the target 21 perpendicular to the laser beam, and thus the rotation angle of the target 21 can be used to represent the direction vector of the laser beam in the target coordinate system.

[0233] In some examples, the Euler angles of the target can be obtained in step S005.

[0234] In some examples, the roll and pitch angles of the target are obtained using a second gravity alignment unit 26 installed on probe 2. In other examples, the roll and pitch angles of the target are obtained using an inclinometer or accelerometer installed on probe 2. In this case, partial Euler angles of the target can be easily obtained, and the transformation relationship between the target coordinate system and the target coordinate system can be represented using partial Euler angles in subsequent processes, thereby enabling the calculation of other Euler angles.

[0235] In some examples, the yaw angle of the target can be calculated based on the rotation angle of target 21 and the target's roll and pitch angles. Calculating the target's yaw angle involves: establishing the coordinate system of the laser tracker device, the target coordinate system, and the target coordinate system; obtaining the transformation relationship between the laser tracker device coordinate system and the target coordinate system; obtaining the direction vector of the laser beam in the laser tracker device coordinate system as the device laser beam vector; obtaining the direction vector of the laser beam in the target coordinate system as the target laser beam vector; obtaining the direction vector of the laser beam in the target coordinate system as the target laser beam vector; establishing an equation and calculating the target's yaw angle. In this case, the yaw angle of probe 2 (or target) can be calculated using the direction vectors of the laser beam in different coordinate systems and the transformation relationships between different coordinate systems.

[0236] In some examples, a first tilt angle can be obtained using a first gravity alignment unit disposed on laser tracker 1, and the transformation relationship between the laser tracker's coordinate system and the target coordinate system can be obtained based on the first tilt angle; a second tilt angle can be obtained using a second gravity alignment unit 26 disposed on probe 2, and the transformation relationship between the target coordinate system and the target coordinate system can be obtained based on the second tilt angle; the device laser beam vector can be obtained based on the rotation angle of laser emitting unit 12. The target laser beam vector can be obtained based on the transformation relationship between the laser tracker's coordinate system and the target coordinate system and the device laser beam vector; the target laser beam vector can be obtained based on the rotation angle of target 21. In this case, different coordinate systems can be established based on different reference frames, and the transformation relationship between different coordinate systems and the target coordinate system can be obtained, thereby enabling the association of the laser beam direction vectors in different coordinate systems and obtaining a formula, which can then be used to calculate the target's yaw angle.

[0237] In some examples, the target laser beam vector can be represented as:

[0238]

[0239] in, O represents the target laser beam vector. T Indicates the target coordinate system. Let α represent the direction vector of the laser beam, α represent the angle of rotation of target 21 in the fourth direction D4 (that is, the angle of rotation of the fourth rotation axis 2321 when target 21 rotates), and β represent the angle of rotation of target 21 in the third direction D3 (that is, the angle of rotation of the third rotation axis 2311 when target 21 rotates). α can be obtained through the second probe angle measurement unit 25, and β can be obtained through the first probe angle measurement unit 24.

[0240] In some examples, the target laser beam vector and the target laser beam vector can satisfy:

[0241]

[0242] in, O represents the target laser beam vector. G Indicates the target coordinate system. This indicates the transformation relationship between the target coordinate system and the target coordinate system. It can be obtained by calculating the second tilt angle.

[0243] In some examples, the transformation relationship between the target coordinate system and the target coordinate system can satisfy:

[0244]

[0245] in, This represents the transformation relationship between the target coordinate system and the target coordinate system, ω, δ, and Let Rx(ω) represent the roll angle, yaw angle, and pitch angle of probe 2 (or target), respectively, and let Rx(ω) represent the rotation matrix related to the roll angle. Rz(δ) represents the rotation matrix related to the pitch angle, and Rz(δ) represents the rotation matrix related to the yaw angle.

[0246] In some examples, the target laser beam vector and the device laser beam vector can satisfy:

[0247]

[0248] in, O represents the laser beam vector of the device. L Indicates the coordinate system of the laser tracker equipment. This indicates the transformation relationship between the laser tracker's coordinate system and the target's coordinate system. The distance from the mechanical zero point of the laser tracker 1 to the center of the cone and the rotation angle of the laser tracker 1 obtained by the tracking head angle measurement unit can be calculated. It can be calculated using the first tilt angle.

[0249] In some examples, the target's angular velocity can be measured while the target is moving, and the second tilt angle can be corrected using the target's angular velocity and the Kalman algorithm. In some examples, as described above, the target's angular velocity can be measured using a gyroscope mounted on probe 2. In this case, since the gyroscope has high angular measurement accuracy over a short period of time, it is suitable for measuring angular velocity under motion. The second tilt angle can be corrected using filtering algorithms such as Kalman, thereby improving the dynamic measurement accuracy of the second tilt angle.

[0250] While the present disclosure has been specifically described above in conjunction with the accompanying drawings and examples, it is to be understood that the foregoing description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from its essential spirit and scope, and all such modifications and variations shall fall within the scope of the present disclosure.

Claims

1. An actively retrofitted six-dimensional laser tracking measurement system, characterized by, The application relates to a laser tracker and a probe cooperating with the laser tracker and arranged on a target, the laser tracker being configured to emit a laser beam; the probe comprising a target configured to reflect the laser beam, a position sensing unit configured to receive the laser beam, and a tracking control unit configured to control the posture of the target based on sensing information obtained by the position sensing unit, the probe actively tracking the laser tracker by rotating the target along two directions respectively to make the probe actively track the laser tracker; when the laser tracker is aligned with the probe based on the laser beam reflected by the target, the target is misaligned with the laser tracker or aligned with the laser tracker, and the probe actively tracking the laser tracker means that the target is aligned with the laser tracker. The laser tracker comprises a laser emitting unit configured to emit the laser beam, a first position sensing unit configured to receive the laser beam reflected by the probe, and a first tracking control unit configured to control the emitting direction of the laser emitting unit to make the laser emitting unit track the probe.

2. The six-dimensional laser tracking measurement system of claim 1, wherein, The first tracking control unit comprises a first rotating mechanism configured to control the laser emitting unit to rotate along a first direction and a second rotating mechanism configured to control the laser emitting unit to rotate along a second direction.

3. The six-dimensional laser tracking measurement system of claim 2, wherein, The laser tracker comprises a first gravity alignment unit configured to obtain a first inclination angle, the first inclination angle being configured to align first direction information to a target coordinate system, the first direction information comprising a rotation angle of the laser emitting unit rotating along the first direction and a rotation angle of the laser emitting unit rotating along the second direction.

4. The six-dimensional laser tracking measurement system of claim 3, wherein, The target has a through hole; the position sensing unit comprised by the probe is a second position sensing unit, the second position sensing unit being configured to receive the laser beam passing through the through hole.

5. The six-dimensional laser tracking system of claim 1, wherein, The tracking control unit comprised by the probe is a second tracking control unit, the second tracking control unit comprising a third rotating mechanism configured to control the target to rotate along a third direction and a fourth rotating mechanism configured to control the target to rotate along a fourth direction.

6. The six-wavelength laser tracking system of claim 5, wherein, The second position sensing unit is configured to receive the laser beam and form a second light spot, and the second tracking control unit is configured to obtain a posture adjustment mode of the target based on the relative position between the second light spot and a preset zero point, wherein the preset zero point is located at the position of the second light spot when the target is aligned with the laser tracker.

7. The six-dimensional laser tracking system of claim 6, wherein, The probe further comprises a fixed base configured to mount the probe on the target.

8. The six-dimensional laser tracking system of claim 6, wherein, The probe comprises a second gravity alignment unit arranged on the fixed base, the second gravity alignment unit being configured to obtain a second inclination angle of the probe, the second inclination angle being configured to calculate the transformation relationship between a target coordinate system and a target coordinate system.

9. The six-dimensional laser tracking system of claim 8, wherein, The second gravity alignment unit comprises a first inclinometer and a second inclinometer, the mounting direction of the first inclinometer being perpendicular to the extension direction of the rotating shaft of the third rotating mechanism, the mounting direction of the second inclinometer being parallel to the extension direction of the rotating shaft of the fourth rotating mechanism, and the mounting direction of the first inclinometer being perpendicular to the mounting direction of the second inclinometer.

10. The six-dimensional laser tracking system of claim 9, wherein, ​

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