actively tracking the attitude probe of the laser tracker

Abstract

The present disclosure describes a kind of actively tracking attitude probe of laser tracker, install in target and cooperate with laser tracker to obtain the position and attitude of target, including: target, probe position sensing unit and probe tracking control unit, target has through hole and is configured to reflect the laser or scattered light beam emitted by laser tracker to laser tracker, probe position sensing unit is configured to receive the laser passing through through hole and obtain sensing information, probe tracking control unit is configured to control the attitude of target based on sensing information so that target is aligned with laser tracker, alignment is at least part of the laser beam emitted by laser tracker passes through through hole and is parallel to the optical axis of target, probe tracking control unit includes the first rotating mechanism of control target rotation in first direction and the second rotating mechanism of control target rotation in second direction.Thereby, the reverse tracking of target can be realized by probe position sensing unit and probe tracking control unit.

Description

[0001] This application is a divisional application of the invention entitled "Six-Dimensional Probe Based on Reverse Tracking", filed on December 12, 2022, with application number 2022115916763. Technical Field

[0002] This invention relates to the intelligent manufacturing equipment industry, and this disclosure specifically relates to an attitude probe for an active tracking laser tracker. Background Technology

[0003] In precision industry and measurement fields, precision instruments are often used to test the assembled objects during assembly to improve assembly accuracy. After assembly, the machines also need to be calibrated. When measuring the three-dimensional coordinates of an object or a point on an object, its attitude also needs to be measured. Therefore, an attitude detection device capable of simultaneously measuring the three-dimensional coordinates and attitude of the target is required.

[0004] Common attitude detection devices include a probe for emitting and receiving laser beams and a reflector mounted on the workpiece for reflecting the laser beam. The laser beam is used to measure the three-dimensional coordinates of the probe, and a light source mounted on the probe is used to acquire the probe's attitude. However, when the workpiece'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 probe. For example, Chinese Patent Publication No. CN112424563A discloses a multi-dimensional measurement system for accurately calculating the position and orientation of a dynamic object, which utilizes the target (i.e., the probe) to actively track a laser beam unit (i.e., the probe), expanding the acceptable angle range of the reflector element by changing the probe's attitude.

[0005] However, this scheme requires at least three rotating mechanisms on the probe to enable it to rotate around the pitch, yaw, and roll axes respectively. In addition, to confirm the rotation of the roll axis, a gyroscope and multiple levels are needed for measurement, which makes the probe structure complex. Summary of the Invention

[0006] This disclosure is made in view of the above-mentioned situation, and its purpose is to provide a probe structure that can achieve reverse tracking, expand the receivable angle of the probe, and has a simple structure.

[0007] This disclosure provides a six-dimensional probe based on reverse tracking, which is used to install on a target and cooperate with a laser tracker to obtain the position and attitude of the target. The probe includes: a fixed base, a target, a probe position sensing unit, a probe tracking control unit, and a probe gravity alignment unit. The fixed base is configured to install the probe on the target. The target has a through-hole and is configured to reflect a laser or scattered beam emitted by the laser tracker back to the laser tracker. The probe position sensing unit is configured to receive the laser light passing through the through-hole and obtain sensing information. The probe tracking control unit is configured to control the attitude of the target based on the sensing information so that the target is aligned with the laser tracker. The probe tracking control unit includes a first rotation mechanism for controlling the target to rotate along a first direction and a second rotation mechanism for controlling the target to rotate along a second direction. The probe gravity alignment unit is disposed on the fixed base and configured to measure the attitude of the target.

[0008] In this configuration, reverse target tracking can be achieved, expanding the probe's angular range. Furthermore, since the target remains aligned with the laser beam during reverse tracking, the direction vector of the laser beam in the target coordinate system (described later) can be conveniently represented using the angles of rotation of the target along the first and second directions. The probe's gravity alignment unit can be used to obtain the Euler angles of a portion of the target, and the transformation relationship between the target coordinate system and the target coordinate system (described later) can be obtained based on the angles measured by the probe's gravity alignment unit.

[0009] Additionally, in the six-dimensional probe disclosed herein, optionally, the six-dimensional probe includes a probe angle measurement unit. This probe angle measurement unit includes a first probe angle measurement unit configured to measure the rotation angle of the target along the first direction and a second probe angle measurement unit configured to measure the rotation angle of the target along the second direction. In this case, the rotation angles of the target along the first direction and the second 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.

[0010] Additionally, in the six-dimensional probe disclosed herein, optionally, the probe 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 first rotating mechanism, and the mounting direction of the second inclinometer is parallel to the extension direction of the rotation axis of the second rotating mechanism. In this case, since the sensitive axis of the probe gravity alignment unit matches the rotation axis of the probe tracking control unit, the transformation formula between the target coordinate system and the target coordinate system can be simplified, improving calculation speed and measurement accuracy. Simultaneously, the target tilt angle measured by the first inclinometer can be used as the pitch angle of the fixed base (target), and the target tilt angle measured by the second inclinometer can be used as the roll angle of the fixed base (target).

[0011] Additionally, in the six-dimensional probe disclosed herein, optionally, the first rotating mechanism is disposed on the fixed base. The first rotating mechanism includes a first rotating shaft, a first bearing matching the first rotating shaft, a support arm linked to the first rotating shaft, and a first drive motor for driving the first rotating shaft to rotate. In this case, the first drive motor can be used to drive the first rotating shaft to rotate, thereby driving the support arm to rotate around the first rotating shaft, and thus the support arm can be used to drive the target to rotate around the first rotating shaft.

[0012] Additionally, in the six-dimensional probe disclosed herein, optionally, the second rotating mechanism is disposed on the support arm. The second rotating mechanism includes a second rotating shaft, a second bearing matching the second rotating shaft, and a second drive motor for driving the second rotating shaft to rotate. The target is disposed on the second rotating shaft and is linked to the second rotating shaft. In this case, the second rotating shaft can be disposed on the support arm using the second bearing, thereby enabling the support arm to drive the second rotating shaft and the target disposed on the second rotating shaft to rotate around the first rotating shaft. Simultaneously, the second drive motor can drive the second rotating shaft to rotate, thereby driving the target to rotate around the second rotating shaft, thus enabling the second rotating shaft to drive the target to rotate in a second direction.

[0013] Additionally, in the six-dimensional probe disclosed herein, optionally, the target includes a reference layer configured to mount the probe position sensing unit, a prism layer with a hollow pyramidal prism, and an intermediate layer having the through-hole between the reference layer and the prism layer. In this case, the laser beam can be returned to the laser tracker in a direction opposite to the incident direction, thereby enabling the measurement of the distance from the mechanical zero point of the laser tracker to the center of the pyramid, i.e., the distance between the laser emitting unit and the target. Simultaneously, when the laser beam emitted by the laser emitting unit is incident along the optical axis of the hollow pyramidal prism, i.e., when the target is aligned with the laser emitting unit, the laser beam can pass through the through-hole and form a specific spot at a specific position behind the through-hole. Therefore, whether the target is aligned with the laser emitting unit can be determined based on whether there is a spot at the specific position behind the through-hole.

[0014] Additionally, in the six-dimensional probe disclosed herein, optionally, a filter is provided in the reference layer between the through-hole and the probe position sensing unit. In this case, light outside a specific wavelength range (e.g., the wavelength of the laser beam formed by the laser emitting unit) can be filtered, so that the energy of the light spot formed by the through-hole and the probe position sensing unit comes from the laser beam formed by the laser emitting unit. This reduces the interference from ambient light or the emitting unit, thereby improving the detection accuracy of the laser beam orientation.

[0015] Furthermore, in the six-dimensional probe disclosed herein, optionally, the probe position sensing unit is disposed on the reference layer. The probe position sensing unit includes a photosensitive surface perpendicular to the axis of the hollow corner cone prism. The probe position sensing unit is configured to detect the movement distance of the laser passing through the through-hole relative to a preset zero point via the photosensitive surface and obtain the sensing information. In this case, since the photosensitive surface is perpendicular to the two axes of the target coordinate system, the position of the light spot obtained by the probe position sensing unit can be conveniently used to represent the target's attitude, thereby simplifying the calculation.

[0016] Furthermore, in the six-dimensional probe disclosed herein, optionally, the vertex of the hollow corner cone prism is located at the intersection of the axis of the first rotation axis and the axis of the second rotation axis. In this case, the calculation can be simplified, the calculation speed can be improved, and the accuracy of the calculation can be increased.

[0017] Furthermore, in the six-dimensional probe disclosed herein, optionally, the axis of the first rotation axis is perpendicular to the sensitive plane of the probe gravity alignment unit, and the axis of the second rotation axis is parallel to the sensitive plane. In this case, since the sensitive axis of the probe gravity alignment unit matches the rotation axis of the probe tracking control unit, the transformation formula between the target coordinate system and the target coordinate system can be simplified, the calculation speed can be improved, and the measurement accuracy can be increased. Simultaneously, the target tilt angle measured by the first inclinometer can be used as the pitch angle of the fixed base (target), and the target tilt angle measured by the second inclinometer can be used as the roll angle of the fixed base (target).

[0018] According to this disclosure, a probe structure is provided that enables reverse tracking, expands the receivable angle of the probe, and has a simple structure. 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, in which:

[0020] Figure 1 This is a schematic diagram illustrating an application scenario of the six-dimensional attitude detection device involved in the example of this disclosure.

[0021] Figure 2 This is a schematic diagram showing the six-dimensional probe of the six-dimensional attitude detection device involved in the example of this disclosure.

[0022] Figure 3 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.

[0023] Figure 4 This illustrates the six-dimensional probe of the six-dimensional attitude detection device involved in this disclosure example. Figure 2 A cross-sectional view of the M-M' position.

[0024] Figure 5 This illustrates the target and second rotation axis of the six-dimensional attitude detection device involved in this disclosure example. Figure 2 A cross-sectional view of the N-N' position in the diagram.

[0025] Figure 6 This is a front view showing a portion of the structure of the six-dimensional probe of the six-dimensional attitude detection device involved in the example of this disclosure.

[0026] Figure 7 This illustrates a partial structure of the six-dimensional probe of the six-dimensional attitude detection device involved in this disclosure example. Figure 6 A cross-sectional view of the O-O' position in the diagram.

[0027] Figure 8This illustrates a portion of the structure of the target of the six-dimensional attitude detection device involved in this disclosure example. Figure 6 A cross-sectional view of the O-O' position in the diagram.

[0028] Figure 9 This is a bottom view showing a partial structure of the six-dimensional probe of the six-dimensional attitude detection device involved in this disclosure example. Detailed Implementation

[0029] 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.

[0030] This disclosure relates to a six-dimensional attitude detection device based on reverse tracking, which can be used to measure the six-dimensional coordinates of a target. The six-dimensional attitude detection device may include a laser tracker and a probe that works in conjunction with the laser tracker, with the probe actively tracking the laser tracker. In this case, the probe can simultaneously track the laser tracker in reverse, and the probe can continuously reflect the laser beam emitted by the laser tracker during its movement.

[0031] In some examples, a six-dimensional attitude detection device based on reverse tracking can also be called a six-dimensional attitude detection device, an active reverse tracking six-dimensional attitude detection device, a six-dimensional attitude detection device, or an attitude detection device, etc.

[0032] This disclosure relates to a six-dimensional probe based on reverse tracking, comprising a target, a probe position sensing unit disposed on the target, a first rotation mechanism controlling the horizontal rotation of the target based on sensing information from the probe position sensing unit, and a second rotation mechanism controlling the pitch rotation of the target. In this configuration, the sensing information from the probe position sensing unit can be used to determine whether the target is aligned with a laser beam, and the first and second rotation mechanisms can be used to control the target to align with the laser tracker, thereby achieving reverse tracking of the target and expanding the receivable angle range of the six-dimensional probe.

[0033] This disclosure relates to a six-dimensional probe based on reverse tracking, including a target, a fixed base for mounting the probe on the target, and a probe gravity alignment unit disposed on the fixed base. In this configuration, since the fixed base is mounted on the target, the Euler angles of a portion of the target can be obtained using the probe gravity alignment unit.

[0034] This disclosure relates to a six-dimensional probe based on reverse tracking, including a fixed base, a target, a probe position sensing unit, a probe tracking control unit, and a probe gravity alignment unit. The fixed base is configured to mount the six-dimensional probe on the target. The target has a through-hole and is configured to reflect a laser or scattered beam emitted by a laser tracker back to the tracker. The probe position sensing unit is configured to receive the laser light passing through the through-hole and obtain sensing information. The probe tracking control unit is configured to control the attitude of the target based on the sensing information so that the target is aligned with the tracker. The probe tracking control unit includes a first rotation mechanism for controlling the target to rotate along a first direction and a second rotation mechanism for controlling the target to rotate along a second direction. The probe gravity alignment unit is disposed on the fixed base and configured to measure the attitude of the target. In this configuration, reverse tracking of the target can be achieved, expanding the angular range that the six-dimensional probe can receive. Furthermore, since the target is continuously aligned with the laser beam during reverse tracking, the direction vector of the laser beam in the target coordinate system (described later) can be conveniently represented using the angles of rotation of the target along the first and second directions. The probe gravity alignment unit can be used to obtain the Euler angles of part of the target, and the transformation relationship between the target coordinate system and the target coordinate system (described later) can also be obtained based on the angle measured by the probe gravity alignment unit.

[0035] In some examples, a six-dimensional probe based on reverse tracking may also be called a probe, attitude probe, auxiliary measurement device, receiver, reflector, or target ball, etc.

[0036] In some examples, the target's six-dimensional coordinates (i.e., 6D coordinates) can refer to the target's three position coordinates and three attitude angles (i.e., Euler angles) in space. In other words, a six-dimensional attitude detection device can be used for target spatial position measurement and spatial attitude measurement. Spatial position measurement corresponds to the target's spatial position, which can be represented by the target's position coordinates. Spatial attitude measurement corresponds to the target's spatial attitude, which can be represented by the target's 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 some examples, the target's position coordinates can be calculated based on the target's position coordinates.

[0037] In some examples, reverse tracking can refer to the active tracking of a laser tracker by a six-dimensional probe in a six-dimensional attitude detection device. In some examples, active tracking of a laser tracker by a six-dimensional probe can be understood as follows: since the laser tracker may include a laser emitting unit (described later) that emits a laser beam, and the six-dimensional 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 six-dimensional 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 six-dimensional probe continuously aligned with the laser emitting unit, reverse tracking of the six-dimensional probe (i.e., active tracking of the laser tracker by the six-dimensional probe) can be considered as the six-dimensional probe actively tracking the laser tracker.

[0038] In addition, this disclosure also includes descriptions of orientation, such as "front" and "rear". For a target or other component or unit disposed on the target (e.g., through hole or probe position sensing unit), "front" may refer to the direction from the target to the laser tracker when the target is aligned with the laser tracker; "rear" may refer to the direction from the laser tracker to the target when the laser tracker is aligned with the target.

[0039] Figure 1 This is a schematic diagram illustrating an application scenario of the six-dimensional attitude detection device involved in the examples of this disclosure. See also: [link to example diagram]. Figure 1 The six-dimensional attitude detection device may include a laser tracker 1 and a six-dimensional probe 2 that works in conjunction with the laser tracker 1 to obtain the position and attitude of the target.

[0040] In some examples, the six-dimensional probe 2 can be mounted on a target. In some examples, when the six-dimensional probe 2 is mounted on a target, at least a portion of the six-dimensional probe 2 (e.g., the mounting base 22 described later) can remain relatively stationary with respect to the target. In some examples, the six-dimensional probe 2 may include a target 21 and a mounting base 22 (described later) for placing the six-dimensional probe 2 on the target. In this case, the position and attitude of the target can be obtained by cooperating with the laser tracker 1 using the six-dimensional probe 2 mounted on the target.

[0041] In some examples, the target can be a workpiece, or it can be any object whose spatial position and / or spatial orientation needs to be measured.

[0042] In some examples, when using a six-dimensional attitude detection device, the laser tracker 1 can be set up independently of the six-dimensional probe 2. In some examples, the laser tracker 1 can be set on the ground, and the six-dimensional probe 2 can be set on the target. In this case, the spatial position of the six-dimensional probe 2 can be captured using the laser tracker 1 set on the ground.

[0043] In some examples, the laser tracker 1 may include a laser emitting unit configured to emit a laser beam. In some examples, the laser tracker 1 may receive the laser beam emitted by the laser emitting unit and reflected by the target 21. In this case, the distance between the target 21 and the laser tracker 1 can be obtained using the reflected laser beam.

[0044] In some examples, the laser emitting unit can be a helium-neon laser or a solid-state laser.

[0045] In some examples, the laser tracker 1 may include a laser emitting unit and a tracking head control unit that controls the laser emitting unit to align with the target 21. In other words, the tracking head control unit may be configured to control the emission direction of the laser emitting unit so that the laser emitting unit tracks the six-dimensional probe 2. In this case, the laser emitting unit can be kept aligned with the six-dimensional probe 2 at all times, and the laser tracker 1 can receive the laser beam reflected from the target 21 in real time as the target moves.

[0046] In some examples, the tracking head control unit can drive the laser emitting unit to rotate about the tracking head's horizontal rotation axis and its pitch rotation axis. In some examples, the axes of the tracking head's horizontal rotation axis and its pitch rotation axis are perpendicular and intersect. In some examples, a coordinate system for the laser tracker can be established based on the axes of the tracking head's horizontal rotation axis and its pitch rotation axis. For example, the coordinate system can be set with the intersection of these axes as its origin, the direction of the horizontal rotation axis as its Z-axis, the direction of the pitch rotation axis as its Y-axis, and the direction perpendicular to these axes as its X-axis.

[0047] In some examples, the laser tracker 1 may include a tracking head angle measurement unit, which can be configured to measure the rotation angle of the laser emitting unit under the control of the tracking head tracking control unit. In this case, the rotation angle of the laser emitting unit can be obtained, and the spatial position of the target 21 can be calculated based on the rotation angle of the laser emitting unit and the distance between the laser emitting unit and the target 21. At the same time, the rotation angle of the laser emitting unit under the control of the tracking head tracking control unit can be used to represent the direction vector of the laser beam in the coordinate system of the laser tracker device.

[0048] In some examples, the laser tracker 1 may include a tracking head gravity alignment unit, which in some examples can be used to measure the tilt angle of the laser emitting unit relative to the horizontal plane. In some examples, the tracking head gravity alignment unit may be configured to align the direction vector of the laser beam in the laser tracker device coordinate system to the target coordinate system, wherein alignment may refer to using transformation relationships in different coordinate systems and the coordinates of an arbitrary unit in one coordinate system to determine the coordinates of that arbitrary unit in another coordinate system.

[0049] 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. In this case, the spatial positions of various coordinate systems (such as 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 direction vector of the laser beam in different target coordinate systems and the transformation relationship between the coordinates in different target 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. However, by aligning the direction vector of the laser beam to the target coordinate system and using the target tilt angle to represent the transformation relationship between the target coordinate system and the target coordinate system, an equation about the direction vector of the laser beam can be established, and then the unknown yaw angle can be solved through the equation.

[0050] In some examples, assuming the tracking head gravity alignment unit can include two single-axis accelerometers with orthogonal sensing axes, the unit may include single-axis accelerometer a and single-axis accelerometer b. The sensing axes of accelerometer a and b can lie in the same plane, and this plane can be perpendicular to the horizontal rotation axis of the tracking head. The sensing axis of accelerometer a can be parallel to the pitch rotation axis of the tracking head, and the sensing axis of accelerometer b can be perpendicular to the pitch rotation axis. In this case, since the sensing axes of the tracking head gravity alignment unit match the rotation axis of the tracking head tracking control unit, the transformation formulas between the laser tracker's coordinate system and the target coordinate system can be simplified, improving calculation speed and measurement accuracy. However, this is not a limitation; in other examples, the positional relationship between the sensing axes of the two single-axis accelerometers and the pitch rotation axis of the tracking head may not be parallel or perpendicular.

[0051] In some examples, the six-dimensional probe 2 can be any device capable of reflecting a light beam in the opposite direction of incident.

[0052] Figure 2This is a schematic diagram showing the six-dimensional probe 2 of the six-dimensional attitude detection device involved in the example of this disclosure. Figure 3 This is a schematic diagram showing the first plane S1, the first direction D1, the axis A1 of the first rotation axis 2311, the second plane S2, the second direction D2, and the axis A2 of the second rotation axis 2321 involved in the example of this disclosure. Figure 4 This illustrates the six-dimensional probe 2 of the six-dimensional attitude detection device involved in this disclosure example. Figure 2 A cross-sectional view of the M-M' position. Figure 5 This illustrates the target 21 and the second rotation axis 2321 of the six-dimensional attitude detection device involved in this disclosure example. Figure 2 A cross-sectional view of the N-N' position in the diagram. Figure 6 This is a front view showing a portion of the structure of the six-dimensional probe 2 of the six-dimensional attitude detection device involved in this disclosure example.

[0053] Figure 7 This illustrates a partial structure of the six-dimensional probe 2 of the six-dimensional attitude detection device involved in this disclosure example. Figure 6 A cross-sectional view of the O-O' position in the diagram. Figure 8 This illustrates a partial structure of the target 21 of the six-dimensional attitude detection device involved in this disclosure example. Figure 6 A cross-sectional view of the O-O' position in the diagram. Figure 9 This is a bottom view showing a partial structure of the six-dimensional probe 2 of the six-dimensional attitude detection device involved in this disclosure example.

[0054] See in some examples Figure 2 , Figure 3 , Figure 4 , Figure 6 and Figure 7 The six-dimensional 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 six-dimensional probe 2 onto the target. In this case, the six-dimensional probe 2 can be fixed to the target by the mounting base 22, allowing the six-dimensional probe 2 to be linked with the target. This enables the determination of the position and orientation of the target 21 based on the light beam reflected by the target 21 (including laser beams and scattered beams), and further enables the determination of the position of the mounting base 22 (i.e., the position and orientation of the target) based on the position and orientation of the target 21.

[0055] In some examples, target 21 can be configured to reflect or scatter a laser beam. In some examples, target 21 can have a through-hole 2122 (see [link to example]). Figure 5 In some examples, the through-hole 2122 can be configured to detect whether the laser beam emitted by the laser emitting unit is emitted to the probe position sensing unit 2131 of the target 21.

[0056] See in some examples Figure 2 , Figure 3 and Figure 4 In some examples, the structure of target 21 can be a symmetrical structure, for example, it can be about Figure 3 The second plane S2 in the diagram is symmetric.

[0057] 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 8 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.

[0058] See in some examples Figure 8 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 and the target 21. In some examples, the mechanical zero point can refer to the origin of the laser tracker's coordinate system, and the center of the pyramid can be the origin of the target's coordinate system. In other words, the laser tracker's coordinate system can be established with the mechanical zero point as the origin, and the target's coordinate system can be established with the center of the pyramid as the origin.

[0059] In some examples, the mechanical zero point can refer to the intersection of the horizontal rotation axis and the pitch rotation axis of the tracking head, thereby simplifying the calculation. However, this disclosure is not limited to this, and the mechanical zero point can also be any position.

[0060] In some examples, the center of the pyramid can refer to the vertex V of the reflector 2111 with the notch. For example, the vertex V of the reflector can refer to... Figure 8 The vertex V of the cornerstone prism. In some examples, the position coordinates of the target 21 can refer to the position coordinates of the center of the cornerstone. 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; 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.

[0061] See in some examples Figure 8 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 probe position sensing unit 2131 behind it.

[0062] In some examples, the notched reflector 2111 can be a hollow corner prism. In this case, when the incident light 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.

[0063] In some examples, a hollow 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 beam can be parallel to the direction of the incident beam. However, this disclosure is not limited to this; the hollow pyramidal prism can also be any element capable of reflecting a beam in the opposite direction to the incident beam.

[0064] 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.

[0065] In some examples, the target 21 may include an intermediate layer 212 disposed behind the prism layer 211.

[0066] See in some examples Figure 8 The optical axis Ao 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 is incident along the optical axis Ao of the hollow corner prism, that is, when the target 21 is aligned with the laser emitting unit, the laser beam can pass through the through hole 2122 and will form a specific spot at a specific position behind the through hole 2122 (e.g., the preset zero point described later). Therefore, it is possible to determine whether the target 21 is aligned with the laser emitting unit based on whether there is a spot at the specific position behind the through hole 2122.

[0067] In some examples, a perforated plate 2121 may be provided in the intermediate layer 212 (see Figure 5Furthermore, the through hole 2122 can be disposed 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 disposed on the perforated plate 2121 and on the straight line where the optical axis Ao of the hollow corner prism lies, and the orientation of the through hole 2122 can be on the straight line where the optical axis Ao of the hollow corner prism lies.

[0068] In some examples, the pinhole plate 2121 can be an aluminum plate with through holes 2122. However, this disclosure is not limited to this; the constituent material 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. In some examples, the shape of the through hole 2122 can be arbitrary; for example, the shape of the through hole 2122 can be any shape, such as polygonal, elliptical, or circular. Preferably, the shape of the through hole 2122 can be circular.

[0069] 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 spot.

[0070] See in some examples Figure 5 and Figure 7 The target 21 may include a filter 2123. In some examples, the filter 2123 may be disposed between the pinhole plate 2121 and the probe 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) can be filtered, so that the energy of the light spot formed by the through-hole 2122 and the probe position sensing unit 2131 comes from the laser beam formed by the laser emitting unit. This reduces the interference from ambient light or other light sources, thereby improving the detection accuracy of the laser beam orientation.

[0071] 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 probe position sensing unit 2131, which may be configured to receive a laser beam passing through the via 2122.

[0072] In some examples, the probe position sensing unit 2131 may have a photosensitive surface. In some examples, the photosensitive surface of the probe position sensing unit 2131 may be parallel to the notch plane Sc. In some examples, the photosensitive surface of the probe position sensing unit 2131 may be parallel to the incident plane Si. In some examples, the photosensitive surface of the probe 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 position of the light spot acquired by the probe position sensing unit 2131 can be conveniently used to represent the attitude of the target 21, thereby simplifying the calculation. However, this disclosure is not limited to this; the photosensitive surface of the probe position sensing unit 2131 may also not be parallel to the notch plane Sc.

[0073] In some examples, after the probe position sensing unit 2131 receives the laser beam passing through the through hole 2122, the probe position sensing unit 2131 is configured to detect the movement distance of the laser beam passing through the through hole 2122 relative to a preset zero point through the photosensitive surface and obtain sensing information. Thus, it is possible to determine whether the target 21 is aligned with the laser emitting unit based on the light spot formed by the laser beam on the photosensitive surface of the probe position sensing unit 2131.

[0074] In some examples, the probe position sensing unit 2131 can record the position of the light spot on the photosensitive surface of the probe 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 light spot on the photosensitive surface of the probe position sensing unit 2131. Compared with the prior art, which requires setting multiple light-emitting devices on the six-dimensional 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 probe position sensing unit 2131 does not require setting multiple light-emitting devices on the six-dimensional 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 measurement accuracy of the target 21's attitude. Compared to existing technologies that directly calculate the attitude of the six-dimensional probe 2 (target) using the position information of the light spot set in the position sensing unit of the six-dimensional probe 2, the calculated attitude of the six-dimensional probe 2 (target) is easily affected by the nonlinearity and drift error of the position sensing unit, resulting in unstable target measurement accuracy. However, by using the probe position sensing unit 2131 to obtain the attitude of the target 21 and the attitude adjustment method of the target 21, and aligning the target 21 with the laser emitting unit, the light spot formed by the laser beam is continuously located at a fixed point or servo zero point (i.e., a preset zero point) in the probe position sensing unit 2131. Then, by using components such as the probe angle measurement unit and the probe gravity alignment unit 26 to calculate the attitude of the six-dimensional probe 2 (target) (described later), the influence of the nonlinearity and drift error of the position sensing unit on the accuracy of the attitude of the six-dimensional probe 2 (target) can be effectively reduced, thereby improving the accuracy of target attitude measurement.

[0075] In some examples, the attitude adjustment method of the target 21 can be determined based on the relative position between the light spot and the preset zero point of the probe position sensing unit 2131. The preset zero point can be located at the position of the light spot when the target 21 is aligned with the laser emitting unit.

[0076] In some examples, the probe position sensing unit 2131 can acquire the position of the light spot in real time. In other words, after the probe position sensing unit 2131 forms the light spot, it can continuously acquire the position of the light spot. In this case, the attitude of the target 21 can be continuously determined, and thus 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 probe tracking control unit can be controlled to make the target 21 aligned with the laser emitting unit in real time. In some examples, the probe position sensing unit 2131 can be a position sensor (PSD) or a CCD (charge coupled device) camera.

[0077] In some examples, when the hollow corner prism does not receive the laser beam, it can be assumed that the laser tracker 1 is not aligned with the target 21; when the hollow corner prism receives the laser beam, it can be assumed that the laser tracker 1 is aligned with the target 21; when the hollow corner prism receives the laser beam, and at least a portion of the laser beam passes through the through-hole 2122 and forms a spot in the probe position sensing unit 2131, and the spot formed by at least a portion of the laser beam in the probe position sensing unit 2131 is not located at a preset zero point, it can be assumed 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 prism receives the laser beam, and at least a portion of the laser beam passes through the through-hole 2122 and forms a spot in the probe position sensing unit 2131, and the spot formed by at least a portion of the laser beam in the probe position sensing unit 2131 is located at a preset zero point, it can be assumed 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 attitude detection device is in based on the relationship between the laser beam and the six-dimensional probe 2.

[0078] 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.

[0079] See in some examples Figure 2 The six-dimensional probe 2 may include a probe tracking control unit, which can be configured to control the attitude of the target 21 based on sensing information acquired by the probe position sensing unit 2131 so that the target 21 is aligned with the laser emitting unit. In this case, the probe tracking control unit can be used to drive the target 21 to align the target 21 with the laser emitting unit.

[0080] In some examples, the probe tracking control unit may include a first rotation mechanism 231 (participating in) that controls the target 21 to rotate along a first direction D1. Figure 2 In this case, the target 21 can be controlled to rotate along the first direction D1 using the first rotating mechanism 231 to track the laser tracker 1 in the first direction D1.

[0081] In some examples, the probe tracking control unit may include a second rotation mechanism 232 that controls the target 21 to rotate along the second direction D2 (see...). Figure 4 In this case, the target 21 can be controlled to rotate along the second direction D2 using the second rotating mechanism 232 to track the laser tracker 1 in the second direction D2.

[0082] In some examples, combined Figure 3 and Figure 4 The rotation of target 21 along the first direction D1 can mean that target 21 rotates within the first plane S1, which is perpendicular to the first rotation axis 2311. At this time, target 21 can rotate around the first rotation axis 2311.

[0083] In some examples, when the six-dimensional 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 first plane S1 can be parallel to the mounting surface. In other words, the first plane S1 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 first plane S1 may also change. When the target 21 rotates along the first direction D1, the first rotation axis 2311 can be perpendicular to the mounting surface. However, this disclosure is not limited to this. In some examples, when the first 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 first direction D1, the first rotation axis 2311 of the first rotation mechanism 231 can be in any direction.

[0084] In some examples, combined Figure 3 and Figure 4 The rotation of target 21 along the second direction D2 can mean that target 21 can rotate within the second plane S2. The second plane S2 does not coincide with or parallel to the first plane S1, and the second plane S2 is perpendicular to the second rotation axis 2321. Target 21 can rotate around the second rotation axis 2321.

[0085] In some examples, the second plane S2 can be a plane perpendicular to the notch plane Sc (or the photosensitive surface of the probe position sensing unit 2131). In other words, the second rotation axis 2321 can be parallel to the notch plane Sc (or the photosensitive surface of the probe position sensing unit 2131). In some examples, when the six-dimensional 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 second plane S2 can be perpendicular to the mounting surface. In other words, the second plane S2 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 second plane S2 may also change. When the target 21 rotates along the second direction D2, the second rotation axis 2321 can be parallel to the mounting surface. However, this disclosure is not limited to this. In some examples, when the second 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 second direction D2, the second rotation axis 2321 of the second rotation mechanism 232 can be in any direction.

[0086] In some examples, the first rotation axis 2311 can be perpendicular to the second rotation axis 2321. In other words, the first plane S1 can be perpendicular to the second plane S2. In this case, the attitude adjustment of the target 21 can be conveniently decomposed into rotation along the first direction D1 and rotation along the second direction D2, thereby enabling the first rotation mechanism 231 and the second rotation mechanism 232 to conveniently control the target 21 to face any direction, that is, the optical axis Ao of the target 21 points in any direction.

[0087] In some examples, the axis A1 of the first rotation axis 2311 can intersect the axis A2 of the second rotation axis 2321, and the intersection point of the first rotation axis A1 and the second rotation axis A2 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 occurrence of calculation errors can be reduced, thereby improving the accuracy of the calculation.

[0088] In some examples, the target coordinate system can be a coordinate system with the intersection of the axis A1 of the first rotation axis 2311 and the axis A2 of the second rotation axis 2321 as the origin, the direction of the axis A1 of the first rotation axis 2311 as the Z-axis direction, the direction of the axis A2 of the second rotation axis 2321 as the Y-axis direction, and the direction perpendicular to the axis A1 of the first rotation axis 2311 and the axis A2 of the second rotation axis 2321 as the X-axis direction.

[0089] In some examples, the axis A1 of the first rotation axis 2311 can intersect the axis A2 of the second rotation axis 2321, and the intersection point of the first rotation axis A1 and the second rotation axis A2 can be set at the vertex V of the notched reflector 2111. In other words, the vertex V of the reflector 2111 can be located at the intersection point of the first rotation axis A1 and the second rotation axis A2. In this case, the calculation can be simplified, the calculation speed can be improved, and the accuracy of the calculation can be improved.

[0090] See in some examples Figure 4 The first rotating mechanism 231 may include a first rotating shaft 2311, a first rotating chassis 2313, and at least one support arm 2312 disposed on the first rotating chassis 2313, and the target 21 may be disposed on the support arm 2312. In some examples, the first rotating mechanism 231 may include two support arms 2312, and the target 21 may be disposed between the two support arms 2312.

[0091] In some examples, the first rotating mechanism 231 may be disposed on the fixed base 22. The first rotating mechanism 231 may include a first rotating shaft 2311, a first bearing 2314 that matches the first rotating shaft 2311, a support arm 2312 that is linked to the first rotating shaft 2311, and a first drive motor 2315 that drives the first rotating shaft 2311 to rotate. In this case, the first drive motor 2315 can be used to drive the first rotating shaft 2311 to rotate, thereby driving the support arm 2312 to rotate around the first rotating shaft 2311, and thus driving the target 21 to rotate around the first rotating shaft 2311.

[0092] In some examples, the first rotating mechanism 231 may include a first angle encoder and a first drive card for controlling the first drive motor 2315.

[0093] In some examples, the first rotating mechanism 231 can control the target 21 to rotate along the first direction D1. In some examples, the first rotating base 2313 can be disposed on the first rotating shaft 2311, and the first rotating shaft 2311 can be disposed on the fixed base 22 via the first bearing 2314. In this case, the first rotating mechanism 231 can drive the first rotating shaft 2311 to rotate and drive the first rotating base 2313 disposed on the first rotating shaft 2311 to rotate along the first direction D1, thereby driving the target 21 disposed on the support arm 2312 to rotate along the first direction D1.

[0094] In some examples, the second rotating mechanism 232 may be disposed on the support arm 2312 of the first rotating mechanism 231 and capable of driving the second rotating shaft 2321 to rotate along the second direction D2. In some examples, the second rotating shaft 2321 may be linked with the target 21. In this case, the target 21 can be driven to rotate along the second direction D2 using the second rotating mechanism 232. In some examples, the second rotating mechanism 232 may include a second rotating shaft 2321 that connects to the target 21 and disposes the target 21 on the support arm 2312, a second bearing 2322 that matches the second rotating shaft 2321, a second angle encoder, a second drive motor 2323 that drives the second rotating shaft 2321 to rotate, and a second drive card that controls the second drive motor 2323. In this configuration, the second rotating shaft 2321 can be mounted on the support arm 2312 using the second bearing 2322. This allows the support arm 2312 to drive the second rotating shaft 2321 and the target 21 mounted on the second rotating shaft to rotate around the first rotating shaft 2311. Simultaneously, the second rotating shaft 2321 can be driven to rotate by the second drive motor 2323, thereby causing the target 21 to rotate around the second rotating shaft 2321. As a result, the second rotating shaft 2321 can drive the target 21 to rotate along the second direction D2.

[0095] In some examples, the first rotating shaft 2311 and the second rotating shaft 2321 may be precision shafts, and the first bearing 2314 and the second bearing 2322 that are matched with the first rotating shaft 2311 and the second rotating shaft 2321 may be precision bearings.

[0096] In some examples, the probe tracking control unit can be configured to control the attitude of the target 21 based on sensing information acquired by the probe position sensing unit 2131 so that the target 21 is aligned with the laser emitting unit. Specifically, in the probe position sensing unit 2131, if the light spot is far from the preset zero point, it can be considered that the target 21 is not aligned with the laser emitting unit, and the attitude adjustment method of the target 21 can be calculated based on the relative position between the light spot and the preset zero point. In this case, the probe tracking control unit can be instructed to control the target 21 to track the laser emitting unit in the opposite direction based on the calculation result, where the relative position between the light spot and the preset zero point refers to the position of the light spot relative to the preset zero point.

[0097] In some examples, the probe tracking control unit can be composed of a first rotating mechanism 231 and a second rotating mechanism 232. In this case, the target 21 can be controlled to rotate in two directions. The probe tracking control unit composed of the first rotating mechanism 231 and the second rotating mechanism 232 can reduce manufacturing and design costs. At the same time, when the probe tracking control unit is composed of rotation in the first direction D1 and the second rotating mechanism 232, the target 21 can be controlled to align with the laser emitting unit, and the attitude of the target 21 can also be obtained based on calculations.

[0098] See in some examples Figure 4 The six-dimensional 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 probe 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 six-dimensional probe 2 based on the rotation angle of the target 21, and further obtaining the rotation angle of the target 21 relative to the six-dimensional probe 2, and then calculating the spatial attitude of the target based on the rotation angle of the six-dimensional probe 2. It should be noted that the process of rotating the target 21 using the probe 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 six-dimensional probe 2 can refer to the attitude of the fixed base 22 in the six-dimensional 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 six-dimensional 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 under the control of the probe 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 six-dimensional probe 2 is obtained, which is also the change of the direction vector of the laser beam relative to the target.

[0099] In some examples, calculating the spatial attitude of the target based on the rotation angle of the six-dimensional 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 the target 21, then determining the direction vector of the laser beam in the laser tracker equipment coordinate system based on the rotation angle of the laser emitting unit, and then using the direction vector of the laser beam in different coordinate systems (such as the laser tracker equipment coordinate system, the target coordinate system, and the target coordinate system) and the transformation relationship between different coordinate systems to calculate the yaw angle of the six-dimensional probe 2 (target).

[0100] See in some examples Figure 4 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 a first direction D1 and a second probe angle measurement unit 25 configured to measure the rotation angle of the target 21 along a second direction D2. In this case, the rotation angles of the target 21 along the first direction D1 and the second direction D2 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 first direction D1 and the second direction D2.

[0101] 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 first rotation axis 2311 and a first probe reading head 242 that obtains the rotation angle of the target 21 along the first direction D1 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 second rotation axis 2321 and a second probe reading head 252 that obtains the rotation angle of the target 21 along the second direction D2 based on the second probe optical grating disk 251. In this case, the rotation angle of the first rotation axis 2311 or the second 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.

[0102] See in some examples Figure 4 and Figure 7 The six-dimensional probe 2 may include a probe gravity alignment unit 26. In some examples, the probe gravity alignment unit 26 may be configured to acquire the target's attitude; in some examples, the probe gravity alignment unit 26 may be used to acquire at least one Euler angle of the target. In some examples, the probe gravity alignment unit 26 may be used to acquire the target's pitch and roll angles.

[0103] In some examples, the probe gravity alignment unit 26 can be configured to associate the orientation 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 orientation information acquired by the probe angle measurement unit may include the rotation angle of the target 21 along the first direction D1 and the rotation angle along the second direction D2.

[0104] See in some examples Figure 4 , Figure 6 and Figure 7 The probe 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 probe gravity alignment unit 26 can remain fixed relative to the target without rotating with the target 21, thus enabling the measurement of the target's tilt angle. Furthermore, compared to the scheme where the probe gravity alignment unit 26 is mounted on the target 21, i.e., the probe gravity alignment unit 26 rotates under the drive of the first rotation mechanism 231 or the second rotation mechanism 232, the dynamic response requirements of the probe gravity alignment unit 26 can be reduced, thereby improving the measurement accuracy of the probe gravity alignment unit 26 and simplifying the calculation process.

[0105] In some examples, the probe gravity alignment unit 26 can measure the tilt angle of the fixed base 22 relative to the horizontal plane as the target tilt angle. In other words, the probe gravity alignment unit 26 can be configured to obtain the target tilt angle of the six-dimensional probe 2, and the target tilt angle 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 six-dimensional 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 relative to the horizontal plane can also refer to the tilt angle of the six-dimensional 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 between the target and 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.

[0106] See in some examples Figure 9 The probe 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 probe gravity alignment unit 26 may also include a triaxial accelerometer. In some examples, the probe gravity alignment unit 26 may also include a biaxial accelerometer. In some examples, the probe gravity alignment unit 26 may also include two single-axis inclinometers or a biaxial inclinometer (tilt sensor). In some examples, the probe gravity alignment unit 26 may also include a level. In some examples, the probe gravity alignment unit 26 may include any device capable of tilting the fixed base 22 relative to the horizontal plane. In this case, the transformation relationship between the target coordinate system and the target coordinate system can be calculated by obtaining the two target tilt angles.

[0107] In some examples, the accelerometer in the probe 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, and in some examples, the accelerometer can also be a capacitive pendulum sensor.

[0108] In some examples, assuming the probe gravity alignment unit 26 includes two single-axis inclinometers with orthogonal sensing axes, the probe gravity alignment unit 26 may include a first inclinometer 26a and a second inclinometer 26b (see [reference]). Figure 9 In this configuration, the sensitive axes of the first inclinometer 26a and the second inclinometer 26b can lie in the same plane. The plane formed by the sensitive axes of the first inclinometer 26a and the second inclinometer 26b is called the sensitive plane. This sensitive plane can be perpendicular to the first rotation axis 2311, parallel to the second rotation axis 2311, parallel to the second rotation axis 2321, and perpendicular to the second rotation axis 2321. In other words, the probe 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 first 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 second rotation mechanism 232. The mounting direction of the first inclinometer 26a can also be perpendicular to the mounting direction of the second inclinometer 26b. In this configuration, since the sensitive axis of the probe gravity alignment unit 26 matches the rotation axis of the probe 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 target tilt angle measured by the first inclinometer 26a can be used as the pitch angle of the fixed base 22 (target), and the target tilt angle measured by the second inclinometer 26b can be used as the roll angle of the fixed base 22 (target). However, this is not a limitation; in other instances, the positional relationship between the sensitive axes of the two single-axis inclinometers and the second rotation axis 2321 may not be parallel or perpendicular.

[0109] In some examples, the target tilt angle can be decomposed into a target tilt angle a and a second tilt angle b. In some examples, the target tilt angle a can be obtained by a first inclinometer 26a, and the target tilt angle b can be obtained by a second inclinometer 26b. In some examples, the target tilt angles a and b can also be obtained by a dual-axis inclinometer. In some examples, the target tilt angles a and b can also be obtained by a monolithically integrated triaxial inclinometer, wherein the two sensitive axes of the triaxial inclinometer are parallel and perpendicular to the second rotation axis 2321, respectively.

[0110] In some examples, the probe gravity alignment unit 26 can acquire the target tilt angle in real time. In other words, when calculating the six-dimensional coordinates of the target using a six-dimensional attitude detection device, the probe gravity alignment unit 26 can continuously measure the target tilt angle. In this case, the target tilt angle can be acquired in real time, and the six-dimensional probe 2 Euler angles can be acquired in real time using the target tilt angle.

[0111] In some examples, the six-dimensional probe 2 may also include a gyroscope mounted on the fixed base 22. The gyroscope can be configured to improve the accuracy of the target tilt angle acquired by the probe gravity alignment unit 26 under dynamic conditions. Since the fixed base 22 (target) introduces acceleration other than gravity into the probe gravity alignment unit 26 when it moves, the accuracy of the target tilt angle will decrease. Using a gyroscope can improve the measurement accuracy of the target tilt angle.

[0112] In some examples, the six-dimensional 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 probe gravity alignment unit 26 and the gyroscope measurement data can be fused by using filtering algorithms such as Kalman, which can complement the data measured by the probe gravity alignment unit 26 and the gyroscope measurement data, thereby improving the dynamic measurement accuracy of the target tilt angle.

[0113] In some examples, the six-dimensional probe 2 may not include a gyroscope, thereby reducing manufacturing costs. In other examples, the gyroscope may be an optional component of the six-dimensional probe 2 and may be detachably mounted on the mounting base 22. In this case, the need for equipping or installing a gyroscope can be determined based on the usage scenario.

[0114] See in some examples Figure 1 The six-dimensional attitude detection device may include a data analyzer 3. In some examples, the data analyzer 3 may have built-in analysis software.

[0115] This disclosure also relates to an attitude detection method based on reverse tracking, capable of reverse tracking of a six-dimensional probe 2 and obtaining the Euler angles of the target. In some examples, the attitude detection method based on reverse tracking may also be referred to as a multi-dimensional measurement method, a method for determining target orientation, or a target measurement method. In some examples, the method disclosed herein can be implemented using the six-dimensional probe disclosed herein. However, this disclosure is not limited thereto, and the method disclosed herein can also be applied to other devices capable of implementing these methods.

[0116] In some examples, the target 21 is aligned with the laser emitting unit (step S001); the Euler angles of the target are obtained (step S003). In this case, since the target 21 can be aligned with the laser emitting unit to achieve reverse tracking, the Euler angles of the target can be calculated based on the rotation angle of the target 21.

[0117] In some examples, in step S001, the target 21 can be aligned with the laser emitting unit. In some examples, the target 21 can be rotated in two directions within the six-dimensional probe 2 to align it with the laser emitting unit. In some examples, the two directions can be the first direction D1 and the second direction D2 described above.

[0118] In some examples, a probe 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 spot of the laser beam received by the target 21 on the probe 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 first direction D1 and along the second direction D2 to align the target 21 with the laser emitting unit. In this case, since the laser emitting unit 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 makes 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.

[0119] In some examples, the Euler angles of the target can be obtained in step S003. In some examples, the roll and pitch angles of the target are obtained using the probe gravity alignment unit 26 installed on the six-dimensional probe 2. In some examples, the roll and pitch angles of the target are obtained using an inclinometer or accelerometer installed on the six-dimensional probe 2. In these cases, 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.

[0120] 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 the six-dimensional probe 2 (target) can be calculated using the direction vectors of the laser beam in different coordinate systems and the transformation relationships between different coordinate systems.

[0121] In some examples, the tilt angle of the laser emitting unit relative to the horizontal plane can be obtained using the gravity alignment unit of the tracking head set on the laser tracker 1, and the transformation relationship between the laser tracker's coordinate system and the target coordinate system can be further obtained; the tilt angle of the six-dimensional probe 2 relative to the horizontal plane can be obtained using the probe gravity alignment unit 26 set on the six-dimensional probe 2 as the target tilt angle, 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 the laser emitting unit. The transformation relationship between the laser tracker's coordinate system and the target coordinate system and the device laser beam vector are used to obtain the target laser beam vector; the target laser beam vector is obtained based on the rotation angle of the 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. Then, the direction vectors of the laser beam in different coordinate systems can be correlated and a formula can be obtained, and the yaw angle of the target can be calculated based on the formula.

[0122] In some examples, the target laser beam vector can be represented as:

[0123]

[0124] in, O represents the target laser beam vector. T Indicates the target coordinate system. Let α represent the direction vector of the laser beam, β represent the angle of rotation of target 21 in the second direction D2 (that is, the angle of rotation of the second rotation axis 2321 when target 21 rotates), and β represent the angle of rotation of target 21 in the first direction D1 (that is, the angle of rotation of the first rotation axis 2311 when target 21 rotates). α can be obtained through the second probe angle measuring unit 25, and β can be obtained through the first probe angle measuring unit 24.

[0125] In some examples, the target laser beam vector and the target laser beam vector can satisfy:

[0126]

[0127] 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.

[0128] In some examples, the transformation relationship between the target coordinate system and the target coordinate system can satisfy:

[0129]

[0130] 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 the six-dimensional 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.

[0131] In some examples, the target laser beam vector and the device laser beam vector can satisfy:

[0132]

[0133] 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 from the tilt angle of the laser emitting unit relative to the horizontal plane.

[0134] In some examples, the angular velocity of the target can be measured while the target is moving, and the target tilt angle can be corrected using the target's angular velocity and the Kalman algorithm. In some examples, such as above, the angular velocity of the target can be measured using a gyroscope installed on the six-dimensional 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. By using filtering algorithms such as Kalman, the target tilt angle can be corrected, thereby improving the dynamic measurement accuracy of the target tilt angle.

[0135] 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 attitude probe for actively tracking a laser tracker, mounted on a target and cooperating with the laser tracker to obtain the position and attitude of the target, characterized in that, include: The system includes a target, a probe position sensing unit, and a probe tracking control unit. The target has a through-hole and is configured to reflect a laser or scattered beam emitted by the laser tracker back to the laser tracker. The target includes a reference layer configured to mount the probe position sensing unit, a prism layer with a hollow corner cone prism, and an intermediate layer between the reference layer and the prism layer having the through hole. The probe position sensing unit is configured to receive laser light passing through the through hole and obtain sensing information, and to detect the distance the laser light passing through the through hole moves relative to a preset zero point and obtain the sensing information. The probe tracking control unit is configured to control the attitude of the target based on the sensing information so that the target is aligned with the laser tracker. The alignment is such that at least a portion of the laser beam emitted by the laser tracker passes through the through-hole and is parallel to the optical axis of the target. The probe tracking control unit includes a first rotation mechanism that controls the target to rotate along a first direction and a second rotation mechanism that controls the target to rotate along a second direction.

2. The attitude probe as described in claim 1, characterized in that, It also includes a probe gravity alignment unit configured to measure the attitude of the target.

3. The attitude probe as described in claim 2, characterized in that, It also includes a probe angle measurement unit, which is configured to measure the rotation angle of the target under the control of the probe tracking and control unit. The probe angle measurement unit and the probe gravity alignment unit cooperate to calculate the attitude of the attitude probe.

4. The attitude probe as described in claim 3, characterized in that, It also includes a fixed base, which is configured to mount the attitude probe on the target, and the probe gravity alignment unit is disposed on the fixed base.

5. The attitude probe as described in claim 4, characterized in that, The first rotating mechanism is disposed on the fixed base. The first rotating mechanism includes a first rotating shaft, a first bearing that matches the first rotating shaft, a support arm that is linked to the first rotating shaft, and a first drive motor that drives the first rotating shaft to rotate.

6. The attitude probe as described in claim 5, characterized in that, The second rotating mechanism is disposed on the support arm. The second rotating mechanism includes a second rotating shaft, a second bearing that matches the second rotating shaft, and a second drive motor that drives the second rotating shaft to rotate. The target is disposed on the second rotating shaft and is linked to the second rotating shaft.

7. The attitude probe as described in claim 2, characterized in that, The probe gravity alignment unit includes a first inclinometer and a second inclinometer. The installation direction of the first inclinometer is perpendicular to the extension direction of the rotation axis of the first rotating mechanism, and the installation direction of the second inclinometer is parallel to the extension direction of the rotation axis of the second rotating mechanism. The installation directions of the first inclinometer and the second inclinometer are perpendicular.

8. The attitude probe as described in claim 3, characterized in that, The probe gravity alignment unit is configured to associate the direction information obtained by the probe angle measurement unit with the target coordinate system. The direction information obtained by the probe angle measurement unit includes the rotation angle of the target along the first direction and the rotation angle along the second direction.

9. The attitude probe as described in claim 6, characterized in that, The probe angle measurement unit includes a first probe angle measurement unit configured to measure the rotation angle of the target along the first direction and a second probe angle measurement unit configured to measure the rotation angle of the target along the second direction.

10. The attitude probe as described in claim 9, characterized in that, The first probe angle measurement unit includes a first probe grating disk disposed on the first rotating axis and a first probe reading head that obtains the rotation angle of the target along the first direction based on the first probe grating disk. The second probe angle measurement unit includes a second probe grating disk disposed on the second rotating axis and a second probe reading head that obtains the rotation angle of the target along the second direction based on the second probe grating disk.

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