Method for obtaining the position and orientation of a target

Abstract

The present disclosure provides a method for obtaining the position and orientation of a target, which is a measurement method for obtaining the position and attitude of a target by using a laser tracker having a laser emission unit and a probe provided on the target and having a rotatable target. The measurement method includes: aligning the laser beam emitted by the laser emission unit with the target to obtain the position of the target relative to the laser tracker; controlling the target to rotate in two directions respectively so that the laser beam emitted by the laser emission unit is perpendicularly incident on the second position sensing unit; calculating the Euler angles of the target based on the position of the target relative to the laser tracker and the rotation angles of the target in two directions. In this case, the target can rotate in two directions and then align with the laser emission unit to achieve reverse tracking, and can calculate other Euler angles of the target based on the rotation angle of the target and a partial Euler angle of the target, which can not only expand the acceptable angle range of the target, but also reduce the target control cost.

Description

[0001] This application is a divisional application of the patent application with the application date of December 12, 2022, application number 202211589950.3, and invention name "Measurement Method and Measurement System Based on Reverse Tracking". Technical Field

[0002] The present invention relates to the intelligent manufacturing equipment industry, and particularly relates to a method for obtaining the position and orientation of a target. Background Art

[0003] In the fields of precision industry and measurement, when assembling equipment, people often need to use precision instruments to test the assembled target objects to improve the assembly accuracy. After the equipment is assembled, it is also necessary to calibrate the machine. When measuring the three-dimensional coordinates of a target object or a certain target point on the target object, it is also necessary to measure their postures. Therefore, an attitude detection device that can simultaneously measure the three-dimensional coordinates and postures of the target is required.

[0004] Commonly used attitude detection devices include a tracking head for emitting and receiving laser beams and a probe arranged on the workpiece and used for reflecting the laser beams. The three-dimensional coordinates of the probe are measured by using the laser beams, and the attitude of the probe is obtained by using the light source arranged on the probe. However, during the process of the change of the posture of the workpiece, the laser beams may exceed the receivable angle range (generally ±45°) of the probe, resulting in the reflector of the probe being unable to receive the laser beams, thereby affecting the measurement results.

[0005] For this reason, the prior art discloses an attitude detection device that enables the probe to actively track (i.e., reverse track) the tracking head. For example, Chinese Patent with the publication number CN112424563A discloses a multi-dimensional measurement system for accurately calculating the position and orientation of a dynamic object, which uses a target (i.e., the probe) to actively track a laser beam unit (i.e., the tracking head), and expands the receivable angle range of the reflection element by changing the attitude of the probe.

[0006] However, in the solution involved in this patent, when calculating the position and attitude of the object, it is necessary to rotate the target around three rotation axes, namely the pitch axis, the yaw axis, and the roll axis, respectively, and the control cost of the target is relatively high. Summary of the Invention

[0007] The present disclosure is proposed in view of the above situation, and its purpose is to provide a measurement method and measurement system based on reverse tracking that can calculate the Euler angles of a target based on the rotation angle of a target and partial Euler angles of the target, which can not only expand the receivable angle range of the target, but also reduce the control cost of the target.

[0008] To this end, a first aspect of the present disclosure provides a measurement method based on reverse tracking, which is a measurement method for obtaining the position and attitude of a target by using a laser tracker with a laser emission unit and a probe disposed on the target and having a rotatable target. The measurement method includes: obtaining the position of the target relative to the laser tracker, and in the probe, rotating the target in two directions respectively to align the target with the laser emission unit, and calculating the Euler angles of the target based on the position of the laser tracker and the rotation angles of the target in the two directions.

[0009] In this case, aligning the target with the laser emission unit can achieve reverse tracking of the target, and thus can expand the range of the incident angle of the laser beam that the probe can receive. Since the probe is disposed on the target, the position of the target can be determined by using the position of the target relative to the laser tracker. Since the target is rotated in two directions to align the target with the laser emission unit, calculating the rotation angles of the target in the two directions can control the alignment of the target with the laser emission unit. Compared with the existing method that requires controlling the target to rotate in three directions, the control cost of the target can be reduced. After the target is aligned with the laser emission unit, the Euler angles of the target can be calculated by using the direction vector of the laser beam.

[0010] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, in the laser tracker, controlling the laser beam emitted by the laser emission unit to rotate in a first direction and in a second direction to change the direction of the laser beam emitted by the laser emission unit, making the laser beam emitted by the laser emission unit align with the target, and receiving the laser beam reflected by the target and carrying the distance information of the target, and obtaining the position of the target relative to the laser tracker based on the laser beam carrying the distance information of the target and the rotation angle of the laser emission unit. In this case, the position of the target relative to the laser tracker can be obtained.

[0011] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, the laser beam emitted by the laser emission unit is aligned with the target through preliminary capture and fine aiming. The preliminary capture is to control the laser beam emitted by the laser emission unit to rotate along the first direction and rotate along the second direction so that the laser beam approaches the target until the target receives and reflects the laser beam emitted by the laser emission unit. The fine aiming is that after the laser tracker receives the laser beam reflected by the target, the laser beam emitted by the laser emission unit is controlled to rotate along the first direction and rotate along the second direction so that the laser beam passes through a preset position of the target. The preset position is a through hole located in the target. In this case, even if the laser beam does not reach the target and the laser tracker does not receive the laser beam reflected by the target, the laser beam emitted by the laser emission unit can approach the target through preliminary capture until the target can reflect the laser beam to the laser emission unit, and at the same time, it can be determined whether the laser beam emitted by the laser emission unit is aligned with the target.

[0012] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, the preliminary capture includes: the laser tracker emits a divergent beam, and the target capture unit provided on the laser tracker receives the divergent beam reflected by the target. Based on the target capture spot formed by the divergent beam reflected by the target in the target capture unit, the attitude adjustment method of the laser emission unit is calculated, and the laser beam emitted by the laser emission unit is controlled to rotate along the first direction and rotate along the second direction so that the laser beam approaches the target until the target receives and reflects the laser beam emitted by the laser emission unit. In this case, the laser tracker emits a divergent beam. Even if the laser beam emitted by the laser emission unit is not aligned with the target, the target can easily receive and reflect the divergent beam, and the target capture unit can easily receive the divergent beam reflected by the target. At the same time, the approximate position of the target can be obtained based on the divergent beam reflected by the target, so that the rotation of the laser emission unit can be controlled to make the laser beam emitted by the laser emission unit approach the target.

[0013] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, the fine aiming includes: the first position sensing unit provided on the laser tracker receives the laser beam reflected by the target. Based on the first spot formed by the laser beam reflected by the target in the first position sensing unit, the attitude adjustment method of the laser emission unit is calculated, and the laser beam emitted by the laser emission unit is controlled to rotate along the first direction and rotate along the second direction so that the laser beam passes through the preset position. In this case, since the first position sensing unit receives the laser beam reflected by the target, the laser beam emitted by the laser emission unit can be controlled to be aligned with and track the target in real time with high precision.

[0014] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, a second position sensing unit disposed on the target is used to receive the laser beam passing through the preset position, and the attitude adjustment method of the target is calculated based on the second light spot of the laser beam received by the target on the second position sensing unit, and the target is controlled to rotate along a third direction and rotate along a fourth direction so that the target is aligned with the laser emitting unit. In this case, since after the target is aligned with the laser emitting unit, the laser beam emitted by the laser emitting unit is vertically incident on the target, that is, perpendicular to the second position sensing unit, the direction vector of the laser beam in the target coordinate system can be conveniently represented by the rotation angle of the target.

[0015] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, calculating the Euler angles of the target includes: establishing a laser tracker device coordinate system, a target coordinate system, and a 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 transformation relationship between the laser tracker device coordinate system and the target coordinate system, 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, measuring the roll angle and pitch angle of the target, obtaining the transformation relationship between the target coordinate system and the target coordinate system, establishing an equation and calculating the yaw angle of the target. In this case, the Euler angles of the target can be obtained.

[0016] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, a clinometer or accelerometer disposed on the probe is used to obtain the roll angle and pitch angle of the target. Since the fixed base is disposed on the target and is relatively stationary with respect to the target, the tilt angle of the fixed base relative to the horizontal plane is measured, that is, the tilt angle of the target relative to the horizontal plane, that is, the roll angle and pitch angle of the target.

[0017] In addition, in the measurement method according to the first aspect of the present disclosure, optionally, a first gravity alignment unit provided on the laser tracker is used to obtain an inclination angle of the laser tracker relative to the horizontal plane as a first inclination angle, and a transformation relationship between the device coordinate system of the laser tracker and the target coordinate system is obtained based on the first inclination angle; a second gravity alignment unit provided on the probe is used to obtain an inclination angle of the probe relative to the horizontal plane as a second inclination angle, and a transformation relationship between the target coordinate system and the target coordinate system is obtained based on the second inclination angle; a device laser beam vector is obtained based on the rotation angle of the laser beam emitted by the laser emission unit; a target laser beam vector is obtained based on the transformation relationship between the device coordinate system of the laser tracker and the target coordinate system and the device laser beam vector; a target laser beam vector is obtained based on the rotation angle of the target. In this case, other parameters in the equation except the yaw angle can be obtained through measurement and calculation.

[0018] The second aspect of the present disclosure provides a measurement system based on reverse tracking, including: a laser tracker having a rotatable laser emission unit and a probe provided on a target and having a target that can rotate in two directions, and the measurement system uses the measurement method according to the first aspect of the present disclosure to obtain the position and attitude of the target. In this case, by aligning the target with the laser emission unit, reverse tracking of the target can be achieved, and further, the range of the incident angle of the laser beam that the probe can receive can be expanded. Since the probe is provided on the target, the position of the target can be determined using the position of the target relative to the laser tracker. At the same time, after obtaining the position of the target relative to the laser tracker, the direction vector of the laser beam in the device coordinate system of the laser tracker can be obtained. After the target is aligned with the laser emission unit, the direction vector of the laser beam in the target coordinate system can be obtained according to the rotation angle of the target. Therefore, an equation can be established by means of coordinate transformation. Since the Euler angles of the target are related to the transformation relationship between the device coordinate system of the laser tracker and the target coordinate system, the Euler angles of the target can be calculated based on the equation.

[0019] According to the present disclosure, a measurement method and a measurement system based on reverse tracking can be provided, which can calculate the Euler angles of a target based on the rotation angle of the target and partial Euler angles of the target, can not only expand the range of angles that the target can receive, but also reduce the target control cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Embodiments of the present disclosure will now be further explained in detail only by way of examples with reference to the accompanying drawings.

[0021] Figure 1 FIG. is a schematic diagram of an application scenario of a measurement method based on reverse tracking according to an example of the present disclosure.

[0022] Figure 2 It is a schematic flow chart showing the reverse tracking-based measurement method involved in the examples of the present disclosure.

[0023] Figure 3 It is a schematic flow chart showing the process of aligning the laser beam emitted by the laser emission unit with the target involved in the examples of the present disclosure.

[0024] Figure 4 It is a schematic diagram of the laser tracker involved in the examples of the present disclosure.

[0025] Figure 5a It is a schematic structural diagram of the first embodiment of the internal optical path of the measurement host involved in the examples of the present disclosure.

[0026] Figure 5b It is a schematic structural diagram of the second embodiment of the internal optical path of the measurement host involved in the examples of the present disclosure.

[0027] Figure 5c It is a schematic structural diagram of the third embodiment of the internal optical path of the measurement host involved in the examples of the present disclosure.

[0028] Figure 6 It is a schematic diagram showing the first plane, the first direction, the first rotation axis, the second plane, the second direction, and the second rotation axis involved in the examples of the present disclosure.

[0029] Figure 7 It is a schematic diagram of the device coordinate system of the laser tracker involved in the examples of the present disclosure.

[0030] Figure 8 It is a schematic flow chart showing the preliminary capture process involved in the examples of the present disclosure.

[0031] Figure 9a It is a schematic diagram of the scene during preliminary capture of an embodiment involved in the examples of the present disclosure.

[0032] Figure 9b It is a schematic diagram of the scene during preliminary capture of another embodiment involved in the examples of the present disclosure.

[0033] Figure 10 It is a schematic diagram of the scene after preliminary capture involved in the examples of the present disclosure.

[0034] Figure 11 It is a schematic flow chart showing the fine aiming process involved in the examples of the present disclosure.

[0035] Figure 12 It is a schematic diagram of the scene during fine aiming involved in the examples of the present disclosure.

[0036] Figure 13It is a schematic diagram of the scene after fine aiming involved in the examples of the present disclosure.

[0037] Figure 14 It is a schematic diagram of the probe involved in the examples of the present disclosure.

[0038] Figure 15 It shows a partial structure of the probe involved in the examples of the present disclosure Figure 14 in the cross-sectional schematic diagram at the O-O' position.

[0039] Figure 16 It shows a partial structure of the target involved in the examples of the present disclosure Figure 14 in the cross-sectional schematic diagram at the O-O' position.

[0040] Figure 17 It is a schematic diagram showing the third plane, third direction, third rotation axis, fourth plane, fourth direction, and fourth rotation axis involved in the examples of the present disclosure.

[0041] Figure 18 It is a schematic diagram of the target coordinate system involved in the examples of the present disclosure.

[0042] Figure 19 It is a schematic diagram of the process of the target alignment laser emission unit involved in the examples of the present disclosure.

[0043] Figure 20 It is a schematic diagram of the scene after the target alignment laser emission unit involved in the examples of the present disclosure.

[0044] Figure 21 It is a schematic diagram of the process of calculating the Euler angles of the target involved in the examples of the present disclosure.

[0045] Figure 22 It is a schematic diagram of the laser tracker device coordinate system and the target coordinate system after the target alignment laser emission unit involved in the examples of the present disclosure. Detailed implementation manners

[0046] Hereinafter, with reference to the drawings, the preferred implementation manners of the present disclosure will be described in detail. In the following description, the same reference numerals are given to the same components, and repeated descriptions are omitted. In addition, the drawings are only schematic diagrams, and the dimensional ratios between components or the shapes of components may be different from the actual ones.

[0047] It should be noted that the terms "including" and "having" in this disclosure, and any variations thereof, such as a process, method, system, product, or device including or having a series of steps or units, do not necessarily refer to those steps or units clearly listed, but may include or have other steps or units not clearly listed or inherent to these processes, methods, products, or devices. All methods described in this disclosure can be executed in any suitable order, unless otherwise indicated herein or clearly inconsistent with the context.

[0048] Figure 1 It is a schematic diagram showing the application scenario of the reverse-tracking-based measurement method involved in the examples of this disclosure. Figure 2 It is a schematic flowchart showing the reverse-tracking-based measurement method involved in the examples of this disclosure.

[0049] This disclosure proposes a reverse-tracking-based measurement method, which is a measurement method for measuring the position and attitude of a target. In some examples, referring to Figure 1 , the reverse-tracking-based measurement method can utilize a laser tracker 1 and a probe 2 to obtain the position and attitude of the target. In some examples, the reverse-tracking-based measurement method can also be referred to as a six-dimensional measurement method, a method for obtaining the position and orientation of a target, or a measurement method, etc. Among them, the position of the target can be the position of the target relative to the laser tracker 1, and the attitude of the target can be represented by the Euler angles of the target.

[0050] In some examples, the laser tracker 1 can have a rotatable laser emission unit 12 (described later), and the laser emission unit 12 can emit a laser beam. In some examples, the probe 2 can be disposed on the target and have a rotatable target 21 (described later), and the target 21 can reflect a light beam (such as a laser beam or a divergent light beam) to the laser tracker 1.

[0051] In some examples, referring to Figure 2, The measurement method based on reverse tracking may include: obtaining the position of the target 21 relative to the laser tracker 1 (step S100), aligning the target 21 with the laser emitting unit 12 (step S300), and calculating the Euler angles of the target (step S500). In this case, aligning the target 21 with the laser emitting unit 12 can achieve reverse tracking of the target 21, and further can expand the range of the incident angle of the laser beam that the probe 2 can receive. Since the probe 2 is disposed on the target, the position of the target can be determined by using the position of the target 21 relative to the laser tracker 1. At the same time, after obtaining the position of the target 21 relative to the laser tracker 1, the direction vector of the laser beam in the laser tracker device coordinate system can be obtained. After the target 21 is aligned with the laser emitting unit 12, the direction vector of the laser beam in the target coordinate system can be obtained according to the rotation angle of the target 21. Thus, an equation can be established by using the coordinate transformation method. Since the Euler angles of the target are related to the transformation relationship between the laser tracker device coordinate system and the target coordinate system, the Euler angles of the target can be calculated based on the equation.

[0052] Figure 3 FIG. is a schematic flow chart showing the process of aligning the laser beam emitted by the laser emitting unit 12 with the target 21 according to the examples of the present disclosure.

[0053] In some examples, in step S100, the position of the target 21 relative to the laser tracker 1 can be obtained. In some examples, the laser beam emitted by the laser emitting unit 12 can be aligned with the target 21, and the position of the target 21 relative to the laser tracker 1 can be obtained based on the laser beam reflected by the target 21.

[0054] In some examples, the position of the target 21 relative to the laser tracker 1 may include direction information and distance information. The direction information of the target 21 relative to the laser tracker 1 may refer to the azimuth angle of the target 21 relative to the laser tracker 1, and the distance information of the target 21 relative to the laser tracker 1 may refer to the distance between the target 21 and the laser tracker 1. Specifically, the azimuth angle of the target 21 relative to the laser tracker 1 may refer to the azimuth angle of the origin OT of the target coordinate system in the laser tracker device coordinate system, and the distance between the target 21 and the laser tracker 1 may refer to the distance between the origin OT of the target coordinate system and the origin OL of the laser tracker device coordinate system.

[0055] In some examples, the position of the target can be obtained by using the position of the target 21 relative to the laser tracker 1. In some other examples, the position of the target 21 relative to the laser tracker 1 can also be used as the position of the target.

[0056] In some examples, refer to Figure 3, obtaining the position of the target 21 relative to the laser tracker 1 may include: preliminary capture (step S110), fine aiming (step S130), and calculating the position of the target 21 (step S150).

[0057] Figure 4 is a schematic diagram showing the laser tracker 1 involved in the examples of the present disclosure. Figure 5a is a schematic structural diagram of a first embodiment showing the internal optical path of the measurement host 11 involved in the examples of the present disclosure. Figure 5b is a schematic structural diagram of a second embodiment showing the internal optical path of the measurement host 11 involved in the examples of the present disclosure. Figure 5c is a schematic structural diagram of a third embodiment showing the internal optical path of the measurement host 11 involved in the examples of the present disclosure. Figure 6 is a schematic diagram showing the first plane S1, the first direction D1, the first rotation axis A1, the second plane S2, the second direction D2, and the second rotation axis A2 involved in the examples of the present disclosure. Figure 7 is a schematic diagram showing the device coordinate system of the laser tracker involved in the examples of the present disclosure.

[0058] In some examples, referring to Figure 4 , Figure 5a , Figure 5b and Figure 5c , the laser tracker 1 may include a measurement host 11, and the measurement host 11 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 components can be protected by the housing. In some examples, referring to Figure 5a , Figure 5b and Figure 5c , the components disposed in the internal chamber may include a laser emitting unit 12. In some examples, the laser tracker 1 may use the laser emitting unit 12 to emit a laser beam.

[0059] In some examples, in the laser tracker 1, the laser emitting unit 12 may be controlled to rotate along the first direction D1 and along the second direction D2 to change the direction of the laser beam emitted by the laser emitting unit 12. In this case, the attitude of the laser emitting unit 12 can be controlled so that the laser beam emitted by the laser emitting unit 12 is aligned with the target 21. In some examples, the laser emitting unit 12 may be disposed in the measurement host 11, and the laser emitting unit 12 may be linked with the measurement host 11. The rotation angle of the measurement host 11 may also be the rotation angle of the laser emitting unit 12. Thus, the direction of the laser beam emitted by the laser emitting unit 12 can be changed by controlling the attitude of the measurement host 11.

[0060] In some examples, after the laser beam emitted by the laser emitting unit 12 is aligned with the target 21, the laser beam carrying the distance information of the target 21 reflected by the target 21 can be received, and the position of the target 21 can be obtained based on the rotation angle between the laser beam carrying the distance information of the target 21 and the laser beam emitted by the laser emitting unit 12. In this case, the position of the target 21 can be obtained, that is, the position of the target 21 relative to the laser tracker 1 can be obtained.

[0061] In some examples, referring to Figure 5a , Figure 5b and Figure 5c , in the measurement host 11, an absolute ranging module 113 and an interference ranging module 114 may further be included. Since the laser beam reflected by the target 21 carries the distance information of the target 21, the absolute ranging module 113 and the interference ranging module 114 can measure the distance between the target 21 and the laser tracker 1 based on the absolute ranging principle and the interference ranging principle respectively. At the same time, the cooperation of the absolute ranging module 113 and the interference ranging module 114 to measure the distance between the target 21 and the laser tracker 1 can improve the measurement accuracy. At the same time, compared with only using the absolute ranging module 113 to measure the distance, the interference ranging module 114 has a faster ranging speed, so the measurement speed can also be improved. In some examples, referring to Figure 5a , Figure 5b and Figure 5c , the optical paths where the absolute ranging module 113 is located and the optical path where the interference ranging module 114 is located can be coupled through the beam combining unit 112.

[0062] In some examples, referring to Figure 5a , the optical path where the absolute ranging module 113 is located can be transmitted through the beam combining unit 112 and emitted from the measurement host 11, and the optical path where the interference ranging module 114 is located can be reflected by the beam combining unit 112 and emitted from the measurement host 11. However, the present disclosure is not limited thereto. Referring to Figure 5b , the optical path where the absolute ranging module 113 is located can be reflected by the beam combining unit 112 and emitted from the measurement host 11, and the optical path where the interference ranging module 114 is located can be transmitted through the beam combining unit 112 and emitted from the measurement host 11.

[0063] In some examples, the laser beam can be emitted from the window piece 115. In some examples, in the laser tracker 1, the laser emitting unit 12 and the measurement host 11 can be rotated to adjust the emitting direction of the laser. In some examples, the laser beam emitted by the laser emitting unit 12 may be refracted or reflected. At this time, the laser emitting unit 12 being aligned with the target 21 may refer to the laser beam emitted by the laser emitting unit 12 being aligned with the target 21, and the rotation of the laser emitting unit 12 may refer to the rotation of the laser beam emitted by the laser emitting unit 12.

[0064] Specifically, referring toFigure 6 When the laser emission unit 12 rotates along the first direction D1, it may mean that the laser emission unit 12 (or the laser beam emitted by the laser emission unit 12) rotates within the first plane S1, and the first plane S1 is perpendicular to the first rotation axis A1. At this time, the laser emission unit 12 (or the laser beam emitted by the laser emission unit 12) can rotate around the first rotation axis A1. When the laser emission unit 12 rotates along the second direction D2, it may mean that the laser beam emitted by the laser emission unit 12 rotates within the second plane S2, and the second plane S2 is perpendicular to the second rotation axis A2. At this time, the laser emission unit 12 (or the laser beam emitted by the laser emission unit 12) can rotate around the second rotation axis A2. The first rotation axis A1 and the second rotation axis A2 are perpendicular and intersect. In some examples, the first plane S1 may be a horizontal plane, the first direction D1 may be a horizontal direction, the second plane S2 may be a vertical plane, and the second direction D2 may be a pitching direction.

[0065] In some examples, referring to Figure 7 The device coordinate system of the laser tracker may be a coordinate system with the intersection point of the first rotation axis A1 and the second rotation axis A2 as the origin OL, the direction of the first rotation axis A1 as the ZL axis direction, the direction of the second rotation axis A2 as the YL axis direction, and the direction perpendicular to the first rotation axis A1 and the second rotation axis A2 as the XL axis direction.

[0066] In some examples, the laser beam emitted by the laser emission unit 12 can be aligned with the target 21 through preliminary capture and fine aiming.

[0067] In some examples, the preliminary capture can be to control the laser emission unit 12 (or the laser beam emitted by the laser emission unit 12) to rotate along the first direction D1 and along the second direction D2 so that the laser beam approaches the target 21 until the target 21 receives and reflects the laser beam emitted by the laser emission unit 12. In this case, even if the laser beam is not emitted to the target 21 and the laser tracker 1 does not receive the laser beam reflected by the target 21, the laser beam emitted by the laser emission unit 12 can still approach the target 21 until the target 21 can reflect the laser beam to the laser emission unit 12.

[0068] In some examples, the fine aiming can be that after the laser tracker 1 receives the laser beam reflected by the target 21, control the laser emission unit 12 (or the laser beam emitted by the laser emission unit 12) to rotate along the first direction D1 and along the second direction D2 so that the laser beam passes through a preset position of the target 21, and the preset position can be a through hole located on the target 21. In this case, it is possible to judge whether the laser beam emitted by the laser emission unit 12 is aligned with the target 21 based on whether the laser beam passes through the through hole.

[0069] Figure 8It is a schematic flowchart of the preliminary capture involved in the examples of the present disclosure. Figure 9a It is a schematic diagram of the scene during the preliminary capture of an embodiment involved in the examples of the present disclosure. Figure 9b It is a schematic diagram of the scene during the preliminary capture of another embodiment involved in the examples of the present disclosure. Figure 10 It is a schematic diagram of the scene after the preliminary capture involved in the examples of the present disclosure.

[0070] In some examples, referring to Figure 5a 、 Figure 5b and Figure 5c , the measurement host 11 may include a light emitting unit 14 and a target capture unit 15, and the light emitting unit 14 and the target capture unit 15 may cooperate to achieve preliminary capture.

[0071] In some examples, the measurement host 11 may include at least one target capture unit 15. Referring to Figure 5c , when the measurement host 11 includes multiple target capture units 15, the target capture units 15 may be symmetrically arranged with respect to the window sheet 115.

[0072] In some examples, referring to Figure 8 , the preliminary capture may include: the laser tracker 1 emits a divergent beam (step S111), the target capture unit 15 provided on the laser tracker 1 receives the divergent beam reflected by the target 21 (step S113), calculates the attitude adjustment method of the laser emission unit 12 based on the target capture spot formed by the divergent beam reflected by the target 21 in the target capture unit 15 (step S115), and controls the laser emission unit 12 to rotate along the first direction D1 and rotate along the second direction D2 so that the laser beam approaches the target 21 until the target 21 receives and reflects the laser beam emitted by the laser emission unit 12 (step S117). In this case, since the laser tracker 1 emits a divergent beam and the illumination range is relatively wide, even if the laser beam is not emitted to the target 21, the target 21 can easily receive and reflect the divergent beam, the target capture unit 15 can easily receive the divergent beam reflected by the target 21, and at the same time, the approximate position of the target 21 can be obtained based on the divergent beam reflected by the target 21, so that the rotation of the laser emission unit 12 can be controlled to make the laser beam emitted by the laser emission unit 12 approach the target 21.

[0073] In some examples, in step S111, the laser tracker 1 may emit a divergent beam. In some examples, the divergent beam may be emitted by the light emitting unit 14 in the measurement host 11, and the target 21 may reflect the divergent beam back to the laser tracker 1 in the opposite direction. In some examples, the laser tracker 1 may use multiple light emitting units 14 to emit divergent beams.

[0074] In some examples, referring toFigure 9a , a target capture unit 15 can be used to achieve preliminary capture. In some examples, see Figure 9b , or multiple target capture units 15 can be used to achieve preliminary capture, and the multiple target capture units 15 can be symmetrically arranged with respect to the window piece 115.

[0075] In some examples, in step S113, the divergent light beam reflected by the target 21 can be received by the target capture unit 15 provided on the laser tracker 1. In some examples, a light spot can be formed when the divergent light beam reaches the target capture unit 15. Let the light spot formed by the divergent light beam on the target capture unit 15 be the target capture light spot. Based on the relative position between the target capture light spot and the target capture zero point, the attitude adjustment method of the laser emitting unit 12 can be calculated. The target capture zero point can be located at the position of the target capture light spot when the laser beam emitted by the laser emitting unit 12 is aligned with the target 21. In some examples, the target capture zero point can be obtained by calibrating the laser tracker 1. In addition, the relative position between the target capture light spot and the target capture zero point can refer to the position of the target capture light spot relative to the target capture zero point.

[0076] In some examples, in step S115, the attitude adjustment method of the laser emitting unit 12 can be calculated based on the target capture light spot formed by the divergent light beam reflected by the target 21 on the target capture unit 15. In some examples, the attitude adjustment method of the laser emitting unit 12 can include the rotation angle of the laser emitting unit 12 (or the laser beam emitted by the laser emitting unit 12) rotating along the first direction D1 and the rotation angle rotating along the second direction D2.

[0077] In some examples, see Figure 10 , in step S117, the laser emitting unit 12 (or the laser beam emitted by the laser emitting unit 12) can be controlled to rotate along the first direction D1 and rotate along the second direction D2 so that the laser beam approaches the target 21 until the target 21 receives and reflects the laser beam emitted by the laser emitting unit 12. In this case, through preliminary capture, the attitude of the laser emitting unit 12 can be quickly adjusted to make the laser beam approach the target 21, and the target 21 can receive the laser beam, which is beneficial to performing more accurate fine aiming.

[0078] Figure 11 is a schematic flowchart showing the fine aiming involved in the examples of the present disclosure. Figure 12 is a schematic scene diagram showing the fine aiming involved in the examples of the present disclosure. Figure 13 is a schematic scene diagram showing the situation after the fine aiming involved in the examples of the present disclosure.

[0079] In some examples, see Figure 11, fine aiming may include: using a first position sensing unit 116 provided in the laser tracker 1 to receive the laser beam reflected by the target 21 (step S131), calculating the attitude adjustment method of the laser emitting unit 12 based on the first light spot formed by the laser beam reflected by the target 21 on the first position sensing unit 116 (step S133), and controlling the laser emitting unit 12 (or the laser beam emitted by the laser emitting unit 12) to rotate along the first direction D1 and rotate along the second direction D2 so that the laser beam passes through a preset position of the target 21 (step S135). In this case, since the first position sensing unit 116 receives the laser beam reflected by the target 21, the laser beam emitted by the laser emitting unit 12 can be controlled to align with and track the target 21 in real time with high precision. At the same time, due to the high accuracy and sensitivity of the first position sensing unit 116, the control accuracy can be further improved.

[0080] In some examples, referring to Figure 5a and Figure 5c , the measurement host 11 may include a first position sensing unit 116. After the laser tracker 1 receives the laser beam reflected by the target 21, the laser beam may pass through the reflection unit 111 and the beam splitting unit 117 in sequence and reach the first position sensing unit 116.

[0081] In some examples, referring to Figure 12 In step S131, the first position sensing unit 116 provided in the laser tracker 1 may be used to receive the laser beam reflected by the target 21. In some examples, the laser beam reaching the first position sensing unit 116 may form a light spot. Let the light spot formed by the laser beam on the first position sensing unit 116 be the first light spot. The attitude adjustment method of the laser emitting unit 12 is calculated based on the relative position between the first light spot and the first preset zero point. The first preset zero point may be located at the position of the first light spot when the laser beam emitted by the laser emitting unit 12 is aligned with the target 21. The relative position between the first light spot and the first preset zero point may refer to the position of the first light spot relative to the first preset zero point.

[0082] In some examples, referring to Figure 13 In step S135, the laser emitting unit 12 (or the laser beam emitted by the laser emitting unit 12) may be controlled to rotate along the first direction D1 and rotate along the second direction D2 so that the laser beam passes through a preset position of the target 21. In some examples, the preset position of the target 21 may be the through hole of the vertex V, where the vertex V may refer to the vertex V of the corner cube prism before the chamfer is formed. In this case, the laser beam emitted by the laser emitting unit 12 can be aligned with the target 21 through fine aiming. In other words, when the laser beam passes through the through hole and the first light spot is located at the first preset zero point, it can be considered that the laser beam emitted by the laser emitting unit 12 is aligned with the target 21.

[0083] Through the cooperation of initial capture and fine aiming, the laser beam emitted by the laser emitting unit 12 can be aligned with the target 21. Compared with fine aiming, since the accuracy of initial capture is limited by the focusing ability of the target capture unit 15. For example, when the distance between the target 21 and the laser tracker 1 exceeds a certain range (such as when the distance between the target 21 and the laser tracker 1 is relatively far and the target capture unit 15 cannot focus), the position accuracy of the spot formed by the divergent beam received by the target capture unit 15 may decrease. Therefore, compared with fine aiming, the alignment accuracy of initial capture is relatively low. At the same time, compared with fine aiming, since the light emitting unit 14 emits a divergent beam during the initial capture process, the target 21 can easily receive the divergent beam, that is, the target capture unit 15 can easily receive the divergent beam reflected by the target 21. Therefore, initial capture can be easily achieved. In this case, using the cooperation of initial capture with relatively low accuracy but relatively loose implementation conditions and fine aiming with relatively high accuracy but relatively harsh implementation conditions to align the laser beam emitted by the laser emitting unit 12 with the target 21 can improve the tracking speed of the laser emitting unit 12, enable the laser emitting unit 12 to quickly capture the target 21, and also enable the laser beam emitted by the laser emitting unit 12 to be stably aligned with the target 21, improving the measurement accuracy.

[0084] In some other examples, the laser beam emitted by the laser emitting unit 12 can also be aligned with the target 21 in other ways. For example, the attitude of the laser emitting unit 12 can be manually changed to align the laser beam emitted by the laser emitting unit 12 with the target 21.

[0085] In some examples, after the laser beam emitted by the laser emitting unit 12 is aligned with the target 21, the position of the target 21 can be calculated. Since the laser beam is aligned with the target 21, the direction information of the target 21 relative to the laser tracker 1 can also be the direction vector of the laser beam in the device coordinate system of the laser tracker.

[0086] In some examples, in step S150, the rotation angle of the laser emission unit 12, the laser beam emitted by the laser emission unit 12, or the measurement host 11 along the first direction D1 and the rotation angle along the second direction D2 can be measured, and the direction vector of the laser beam in the laser tracker device coordinate system can be represented by using the rotation angle of the laser emission unit 12, the laser beam emitted by the laser emission unit 12, or the measurement host 11 along the first direction D1 and the rotation angle along the second direction D2. Furthermore, the direction information of the target 21 relative to the laser tracker 1 can be obtained by using the direction vector of the laser beam in the laser tracker device coordinate system. Furthermore, the coordinates of the target 21 in the laser tracker device coordinate system can be calculated based on the direction information of the target 21 relative to the laser tracker 1 and the distance information of the target 21 relative to the laser tracker 1.

[0087] In some examples, the direction vector of the laser beam in the laser tracker device coordinate system can satisfy the formula:

[0088]

[0089] Wherein, represents the direction vector of the laser beam in the laser tracker device coordinate system, and α L represents the rotation angle of the laser emission unit 12, the laser beam emitted by the laser emission unit 12, or the measurement host 11 along the second direction D2 (such as the pitch direction), and β L represents the rotation angle of the laser emission unit 12, the laser beam emitted by the laser emission unit, or the measurement host 11 along the first direction D1 (such as the horizontal direction).

[0090] In some examples, the coordinates of the target 21 in the laser tracker device coordinate system can be calculated by using the distance information and direction information described above.

[0091] In some other examples, the position of the target 21 relative to the laser tracker 1 can also be obtained by other means. For example, a light-emitting device capable of emitting light can be provided on the probe 2, and the direction information of the target 21 relative to the laser tracker 1 can be determined based on the position of the light-emitting device in the image. A positioning component can also be provided in the probe 2 and the laser tracker 1 to obtain the position of the target 21 relative to the laser tracker 1.

[0092] Figure 14 is a schematic diagram of the probe 2 involved in the examples of the present disclosure. Figure 15 is a schematic cross-sectional view of a partial structure of the probe 2 involved in the examples of the present disclosure at the Figure 14 O-O' position. Figure 16 is a schematic cross-sectional view of a partial structure of the target 21 involved in the examples of the present disclosure at the Figure 14 O-O' position.Figure 17 It is a schematic diagram showing the third plane S3, the third direction D3, the third rotation axis A3, the fourth plane S4, the fourth direction D4, and the fourth rotation axis A4 involved in the examples of the present disclosure. Figure 18 It is a schematic diagram showing the target coordinate system involved in the examples of the present disclosure.

[0093] In some examples, referring to Figure 14 , the probe 2 may include a target 21 and a fixed base 22 for mounting the probe 2 on the target.

[0094] In some examples, referring to Figure 16 , the target 21 may include a mirror 2111 with a notch. The mirror 2111 with a notch may be a corner cube prism or an optical retroreflector. In this case, the laser beam can be returned to the laser tracker 1 in a direction opposite to the incident direction.

[0095] In some examples, the mirror 2111 with a notch may include an incident plane Si and a notch plane Sc. The notch plane Sc may be parallel to the incident plane Si. The notch plane Sc may refer to the cutting plane forming the notch. The incident plane Si may refer to the plane where the laser beam is incident on the mirror 2111 with a notch. The incident plane Si is perpendicular to the optical axis Ao of the mirror 2111 with a notch.

[0096] In some examples, referring to Figure 16 , the through hole may be located at the vertex V of the mirror 2111 with a notch. After at least a part of the laser beam passes through the through hole, a second light spot can be formed on the second position sensing unit 2131.

[0097] In some examples, the target 21 can rotate along the third direction D3 and the fourth direction D4. In some examples, referring to Figure 17 , the rotation of the target 21 along the third direction D3 may mean that the target 21 rotates within the third plane S3. The third plane S3 is perpendicular to the third rotation axis A3. At this time, the target 21 can rotate around the third rotation axis A3. The rotation of the target 21 along the fourth direction D4 may mean that the target 21 rotates within the fourth plane S4. The fourth plane S4 is perpendicular to the fourth rotation axis A4. At this time, the target 21 can rotate around the fourth rotation axis A4.

[0098] In some examples, referring to Figure 18 , the target coordinate system may be a coordinate system with the intersection point of the third rotation axis A3 and the fourth rotation axis A4 as the origin OT, the direction of the third rotation axis A3 as the ZT axis direction, the direction of the fourth rotation axis A4 as the YT axis direction, and the direction perpendicular to the third rotation axis A3 and the fourth rotation axis A4 as the XT axis direction.

[0099] Figure 19 It is a schematic flow chart showing the alignment of the target 21 with the laser emitting unit 12 according to the examples of the present disclosure. Figure 20 It is a schematic diagram of the scene after the target 21 is aligned with the laser emitting unit 12 according to the examples of the present disclosure.

[0100] In some examples, in step S300, the target 21 can be rotated in two directions respectively to align the target 21 with the laser emitting unit 12. Since the target 21 is rotated in two directions to align the target 21 with the laser emitting unit 12, calculating the rotation angles of the target 21 in the two directions can control the alignment of the target 21 with the laser emitting unit 12. Compared with the existing method that requires controlling the target 21 to rotate in three directions, the control cost of the target can be reduced. In some examples, referring to Figure 19 , the alignment of the target 21 with the laser emitting unit 12 may include: receiving the laser beam passing through the preset position by the second position sensing unit 2131 provided on the target 21 (step S310), calculating the attitude adjustment method of the target 21 based on the second light spot of the laser beam received by the target 21 on the second position sensing unit 2131 (step S330), and controlling the target 21 to rotate in the third direction D3 and in the fourth direction D4 to align the target 21 with the laser emitting unit 12 (step S350). In this case, the target 21 can be aligned with the laser emitting unit 12. Since the laser beam is perpendicular to the incident plane Si and the cut plane Sc at this time, after the target 21 is aligned with the laser emitting unit 12, the laser beam emitted by the laser emitting unit 12 is perpendicularly incident on the target, that is, perpendicular to the second position sensing unit 2131. The direction vector of the laser beam in the target coordinate system can be conveniently represented by the rotation angle of the target 21.

[0101] In some examples, referring to Figure 20 , in step S310, the second position sensing unit 2131 provided on the target 21 can be used to receive the laser beam passing through the preset position. When the laser beam reaches the second position sensing unit 2131, a light spot can be formed. Let the light spot formed by the laser beam on the second position sensing unit 2131 be the second light spot. The attitude adjustment method of the target 21 is calculated based on the relative position between the second light spot and the second preset zero point. 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. The relative position between the second light spot and the second preset zero point may refer to the position of the second light spot relative to the second preset zero point. When the laser beam passes through the through hole and the second light spot is located at the second preset zero point, it can be considered that the target 21 is aligned with the laser emitting unit 12.

[0102] In some examples, in step S330, the attitude adjustment method of the target 21 may include the rotation angle of the target rotating in the third direction D3 and the rotation angle of the target rotating in the fourth direction Dx.

[0103] Figure 21 It is a schematic flow chart showing the Euler angles of the calculation target involved in the examples of the present disclosure. Figure 22 It is a schematic diagram showing the laser tracker device coordinate system and the target coordinate system after the target 21 is aligned with the laser emission unit 12 involved in the examples of the present disclosure.

[0104] In some examples, in step S500, other Euler angles of the target (such as the yaw angle of the target) can be calculated based on the position of the target 21 relative to the laser tracker 1 and the rotation angles of the target 21 in two directions. Specifically, the second gravity alignment unit 26 (see Figure 15 ) can be used to measure the roll angle and pitch angle of the target, and the Euler angles of the target can be calculated based on the direction information of the target 21, the rotation angles of the target 21, the roll angle and pitch angle of the target.

[0105] In some examples, see Figure 21 , calculating the Euler angles of the target may include: establishing a laser tracker device coordinate system, a target coordinate system, and a target coordinate system (step S501), obtaining the transformation relationship between the laser tracker device coordinate system and the target coordinate system (step S503), obtaining the direction vector of the laser beam in the laser tracker device coordinate system as the device laser beam vector (step S505), obtaining the direction vector of the laser beam in the target coordinate system as the target laser beam vector (step S507), obtaining the direction vector of the laser beam in the target coordinate system as the target laser beam vector (step S509), measuring the roll angle and pitch angle of the target (step S511), obtaining the transformation relationship between the target coordinate system and the target coordinate system (step S513), establishing an equation and calculating the yaw angle of the target (step S515). In this case, the Euler angles of the target can be obtained. It should be noted that the step numbers should not be used as a limitation on the order of the steps. For example, step S505 can also be executed before step S503.

[0106] In some examples, see Figure 7 , Figure 18 and Figure 22 , the laser tracker device coordinate system and the target coordinate system can be obtained in the manner described above. In some examples, the target coordinate system can be a coordinate system established based on the gravity direction. For example, in the orthogonal axes of the target coordinate system, the ZG axis can be parallel to the gravity direction, the XG axis and the YG axis can be perpendicular to the gravity direction, and the position of the origin OG of the target coordinate system can be the same as the position of the origin OL of the laser tracker device coordinate system.

[0107] In some examples, in step S503, the first gravity alignment unit provided in the laser tracker 1 can be used to obtain the tilt angle of the laser tracker 1 relative to the horizontal plane as the first tilt angle, and based on the first tilt angle, the transformation relationship between the laser tracker device coordinate system and the target coordinate system can be obtained. Specifically, the laser tracker 1 can include a first gravity alignment unit for measuring the tilt angle of the laser tracker 1 relative to the horizontal plane. The first gravity alignment unit can be provided on the base of the laser tracker 1. The first gravity alignment unit can be an inclinometer or an accelerometer and includes two mutually orthogonal sensitive axes. The two mutually orthogonal sensitive axes include a first sensitive axis parallel to the second rotation axis A2 and a second sensitive axis perpendicular to the second rotation axis A2. The first sensitive axis and the second sensitive axis are perpendicular to the first rotation axis A1.

[0108] In some examples, since the laser tracker 1 can generally be horizontally adjusted before being set up and the attitude of the laser tracker 1 does not change much during use, the first tilt angle measured by the first gravity alignment unit is small. At this time, the transformation relationship between the laser tracker device coordinate system and the target coordinate system can satisfy the formula:

[0109]

[0110] where represents the transformation relationship between the laser tracker device coordinate system and the target coordinate system, and a and b respectively represent the tilt angles of the laser tracker 1 relative to the horizontal plane on the first sensitive axis and the second sensitive axis and can be obtained through the first gravity alignment unit.

[0111] In some examples, in step S505, the device laser beam vector can be obtained based on the rotation angle of the laser emission unit 12. The device laser beam vector can satisfy the formula:

[0112]

[0113] where represents the direction vector of the laser beam in the laser tracker device coordinate system, α L represents the rotation angle of the laser emission unit 12, the laser beam emitted by the laser emission unit 12, or the measurement host 11 along the second direction D2 (for example, the pitch direction), and β L represents the rotation angle of the laser emission unit 12, the laser beam emitted by the laser emission unit 12, or the measurement host 11 along the first direction D1 (for example, the horizontal direction).

[0114] In some examples, in step S507, the target laser beam vector can be obtained based on the transformation relationship between the laser tracker device coordinate system and the target coordinate system and the device laser beam vector. The target laser beam vector can satisfy the formula:

[0115]

[0116] Among them, represents the target laser beam vector.

[0117] In some examples, in step S509, the target laser beam vector can be obtained based on the rotation angle of the target 21, and the target laser beam vector can satisfy the formula:

[0118]

[0119] Among them, represents the target laser beam vector, and α T represents the rotation angle of the target 21 along the fourth direction D4, and β T represents the rotation angle of the target 21 along the third direction D3.

[0120] In some examples, in step S511, the roll angle and pitch angle of the target can be obtained by using the inclinometer or accelerometer provided on the probe 2. Specifically, referring to Figure 15 , the probe 2 may include a second gravity alignment unit 26 for measuring the tilt angle of the fixed base 22 relative to the horizontal plane. The second gravity alignment unit 26 can be an inclinometer or an accelerometer, and includes two mutually orthogonal sensitive axes. The two mutually orthogonal sensitive axes include a third sensitive axis parallel to the fourth rotation axis A4 and a fourth sensitive axis perpendicular to the fourth rotation axis A4. The third sensitive axis and the fourth sensitive axis are perpendicular to the third rotation axis A3. Since the fixed base 22 is provided on the target and is relatively stationary with respect to the target, the second gravity alignment unit 26 can measure the tilt angle of the fixed base 22 relative to the horizontal plane, that is, the tilt angle of the target relative to the horizontal plane, that is, the roll angle and pitch angle of the target.

[0121] In some examples, in step S513, the tilt angle of the probe 2 relative to the horizontal plane can be obtained as the second tilt angle by using the second gravity alignment unit 26 provided on the 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.

[0122] In some examples, when the target moves, the angular velocity of the target can be measured and the second tilt angle can be corrected by using the angular velocity of the target and the Kalman algorithm. Specifically, a gyroscope can be provided on the fixed base 22, and the angular velocity of the target can be measured by using the gyroscope, and the second tilt angle can be corrected. In this case, the dynamic measurement accuracy of the second tilt angle can be improved.

[0123] In some examples, the transformation relationship between the target coordinate system and the target coordinate system can satisfy the formula:

[0124]

[0125] Among them, represents the transformation relationship between the target coordinate system and the target coordinate system, ω, δ and respectively represent the roll angle, yaw angle and pitch angle of the target, Rx(ω) represents the rotation matrix related to the roll angle, represents the rotation matrix related to the pitch angle, and Rz(δ) represents the rotation matrix related to the yaw angle.

[0126] In some examples, in step S515, an equation can be established and the yaw angle of the target can be calculated. The equation can be:

[0127]

[0128] Among them, except for the yaw angle, other parameters can be obtained through measurement and calculation. Therefore, the yaw angle of the target can be calculated based on the equation, and finally the Euler angles of the target can be obtained.

[0129] The present disclosure also relates to a measurement system based on reverse tracking, including a laser tracker 1 having a rotatable laser emitting unit 12 and a probe 2 provided on the target and having a target 21 that can rotate in two directions. The measurement system can obtain the position and attitude of the target by using the measurement method involved in the present disclosure. In this case, by aligning the target 21 with the laser emitting unit 12, reverse tracking of the target 21 can be achieved, and further, the range of the incident angle of the laser beam that the probe 2 can receive can be expanded. Since the probe 2 is provided on the target, the position of the target can be determined by using the position of the target 21 relative to the laser tracker 1. At the same time, after obtaining the position of the target 21 relative to the laser tracker 1, the direction vector of the laser beam in the laser tracker device coordinate system can be obtained. After the target 21 is aligned with the laser emitting unit 12, the direction vector of the laser beam in the target coordinate system can be obtained according to the rotation angle of the target 21. Thus, an equation can be established by using the coordinate transformation method. Since the Euler angles of the target are related to the transformation relationship between the laser tracker device coordinate system and the target coordinate system, the Euler angles of the target can be calculated based on the equation.

[0130] Although the present disclosure has been specifically described above in conjunction with the accompanying drawings and examples, it can be understood that the above description does not limit the present disclosure in any form. Those skilled in the art can make deformations and changes to the present disclosure according to needs without departing from the essential spirit and scope of the present disclosure, and these deformations and changes all fall within the scope of the present disclosure.

Claims

1. A method for obtaining the position and orientation of a target, which is a measurement method for obtaining the position and attitude of the target by using a laser tracker having a laser emitting unit and a probe provided on the target and having a rotatable target, characterized in that, The measurement method includes: controlling the rotation of the laser emission unit so that the laser beam emitted by the laser emission unit passes through a preset position of the target to align with the target, and enabling the laser emission unit to receive the laser beam carrying the distance information of the target reflected by the target, and obtaining the position of the target relative to the laser tracker based on the laser beam carrying the distance information of the target and the rotation angle of the laser emission unit; after the laser beam emitted by the laser emission unit passes through the preset position of the target, in the probe, using the second position sensing unit arranged on the target to receive the laser beam emitted by the laser emission unit, calculating the attitude adjustment mode of the target, and controlling the target to rotate along two directions respectively so that the laser beam emitted by the laser emission unit is vertically incident on the second position sensing unit; calculating the Euler angles of the target based on the position of the target relative to the laser tracker and the rotation angles of the target along two directions, where, Aligning the laser beam emitted by the laser emission unit with the target through fine aiming, and the fine aiming is that after the laser tracker receives the laser beam reflected by the target, controlling the laser beam emitted by the laser emission unit to rotate along a first direction and a second direction so that the laser beam passes through the preset position of the target, and the preset position is a through hole located on the target, When the laser beam passes through the through hole and the light spot is located at the preset zero point, the laser beam emitted by the laser emission unit is aligned with the target.

2. The measurement method according to claim 1, characterized in that, The fine aiming includes: using the first position sensing unit arranged on the laser tracker to receive the laser beam reflected by the target, calculating the attitude adjustment mode of the laser emission unit based on the first light spot formed by the laser beam reflected by the target on the first position sensing unit, and controlling the laser beam emitted by the laser emission unit to rotate along the first direction and the second direction so that the laser beam passes through the preset position.

3. The measuring method according to claim 1, wherein Enabling the laser beam emitted by the laser emission unit to be received and reflected by the target through preliminary capture, and the preliminary capture is controlling the laser emission unit to rotate along a first direction and a second direction so that the laser beam approaches the target until the target receives and reflects the laser beam emitted by the laser emission unit.

4. The measuring method according to claim 1, characterized in that Using the second position sensing unit arranged on the target to receive the laser beam passing through the preset position, calculating the attitude adjustment mode of the target based on the second light spot of the laser beam received by the target on the second position sensing unit, and controlling the target to rotate along a third direction and a fourth direction so that the target is aligned with the laser emission unit.

5. The measurement method according to claim 1, characterized in that, Calculating the Euler angles of the target includes: Establish the device coordinate system, target coordinate system and target coordinate system of the laser tracker; obtain the direction vector of the laser beam in the device coordinate system of the laser tracker as the device laser beam vector; obtain the transformation relationship between the device coordinate system of the laser tracker and the target coordinate system; obtain the direction vector of the laser beam in the target coordinate system as the target laser beam vector; obtain the direction vector of the laser beam in the target coordinate system as the target laser beam vector; measure the roll angle and pitch angle of the target; obtain the transformation relationship between the target coordinate system and the target coordinate system; establish an equation and calculate the yaw angle of the target.

6. The measuring method according to claim 5, characterized in that, Use the first gravity alignment unit provided in the laser tracker to obtain the inclination angle of the laser tracker relative to the horizontal plane as the first inclination angle, and obtain the transformation relationship between the device coordinate system of the laser tracker and the target coordinate system based on the first inclination angle; use the second gravity alignment unit provided in the probe to obtain the inclination angle of the probe relative to the horizontal plane as the second inclination angle, and obtain the transformation relationship between the target coordinate system and the target coordinate system based on the second inclination angle; obtain the device laser beam vector based on the rotation angle of the laser beam emitted by the laser emission unit; obtain the target laser beam vector based on the transformation relationship between the device coordinate system of the laser tracker and the target coordinate system and the device laser beam vector; obtain the target laser beam vector based on the rotation angle of the target.

7. The measuring method according to claim 6, characterized in that, Use the second gravity alignment unit to obtain the roll angle and pitch angle of the target.

8. The measuring method according to claim 6, characterized in that, When the target moves, measure the angular velocity of the target and use the angular velocity of the target and the Kalman algorithm to correct the second tilt angle.

9. The measurement method according to claim 7, characterized in that, The first gravity alignment unit is an inclinometer or an accelerometer, and the second gravity alignment unit is an inclinometer or an accelerometer.

Images