Laser tracker rotary table shafting deformation measurement system and method

Abstract

The invention relates to a laser tracker rotary table shafting deformation measurement system and method, and belongs to the technical field of instrument measurement and calibration. The system comprises a pitching driving bearing module which is internally provided with a bearing frame; the pitching driving bearing module is used for driving the bearing frame to perform pitching motion; the position acquisition module is used for acquiring position data of the laser tracker turntable shaft system in real time; the monitoring module is connected with the pitching driving bearing module and used for collecting measurement displacement data of a preset monitoring area of the bearing frame; the calculation module is connected with the monitoring module and used for calculating the total deformation angle of the bearing frame according to the measured displacement data; and the measurement result output module is respectively connected with the position acquisition module and the calculation module and is used for comparing the total deformation angle with a threshold value and combining the position data to obtain a measurement result of the laser tracker rotary table shafting. According to the invention, the error detection precision and resolution are improved, and the field adaptability and arrangement flexibility are improved.

Description

Technical Field

[0001] This invention relates to the field of instrument measurement and calibration technology, and in particular to a laser tracker turntable shaft deformation measurement system and method. Background Technology

[0002] In large-scale, high-precision measurement scenarios in aerospace, transportation equipment, and precision manufacturing, laser trackers, with their core capabilities of combining high-precision ranging and angle measurement, have become indispensable 3D measurement equipment for on-site assembly and geometric calibration. The core support for their measurement accuracy lies in the operational stability of the pitch and azimuth dual-axis turntable system. The axial runout generated during continuous rotation of the pitch axis directly determines the accuracy of the laser beam's angular pointing and the consistency of the ranging path. Although the deformation of this axial runout is typically on the order of micrometers or even nanometers, in large-scale measurement scenarios, the error is significantly amplified through the measurement link, becoming a key bottleneck restricting further improvements in the measurement accuracy of laser trackers. Therefore, achieving structured detection and real-time monitoring of the minute runouts during the operation of the laser tracker's axis system is a fundamental prerequisite for ensuring its measurement reliability.

[0003] Existing technologies for addressing axis runout in laser trackers primarily focus on correcting static or quasi-static errors, failing to cover time-varying runout during dynamic operation. For example, patent CN115307579A uses dual probe projection to achieve pitch-azimuth axis perpendicularity adjustment, converging the axis geometric attitude but failing to track time-varying runout; CN115371558A uses parallel light projection shadow lines to improve axis concurrency and consistency, but still remains within the scope of static / quasi-static error verification; while CN119164286A provides an interface to distinguish between adjustment offset and running runout, it lacks online decomposition and closed-loop correction of runout harmonics and angle synchronization components; CN106643505A verifies the impact of runout on length measurement accuracy and proposes a desensitization approach, but requires high alignment and has not yet outputted angle synchronization compensation parameters that can be directly written into firmware. None of these existing technologies have formed a solution that balances dynamics, integration, and stability.

[0004] In other shaft wobble detection methods, existing technology CN106767555A utilizes a laser rangefinder and angle measuring device to apply a reflector to the shaft end face to directly observe runout changes. While this method can sense runout trends, it suffers from limitations such as limited measurement point distribution, poor structural symmetry, and weak common-mode error suppression, making it difficult to maintain measurement stability in complex dynamic environments. Similarly, existing technology CN205403703U senses runout through optical devices on the spindle end face. Designed for machining spindles, it differs significantly from laser trackers in structural dimensions and load paths, lacking versatility and integration, and cannot be adapted to the limited internal space of laser trackers.

[0005] In summary, current laser tracker axis runout detection and compensation technologies have three main shortcomings: First, they lack integration and real-time performance. Traditional devices are large and complex, making them difficult to integrate and unable to perform real-time online monitoring. Second, they have weak measurement stability and anti-interference capabilities. Single-point or single-sided measurements are susceptible to local errors and environmental common-mode interference, and lack effective compensation mechanisms. Third, they have poor adaptability to complex environments. They rely on high-precision optical assembly and reflective surfaces, making long-term stable operation in industrial settings difficult. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the poor integration and real-time performance, weak measurement stability and anti-interference ability, and poor adaptability to complex environments in the prior art.

[0007] In a first aspect, to solve the above-mentioned technical problems, the present invention provides a laser tracker turntable shaft deformation measurement system, comprising: The pitch drive load-bearing module has a built-in load-bearing frame (7); the pitch drive load-bearing module is used to drive the load-bearing frame (7) to pitch. The position acquisition module is used to acquire the position data of the laser tracker turntable axis system in real time; The monitoring module is connected to the pitch drive bearing module and is used to collect the measured displacement data of the preset monitoring area of ​​the bearing frame (7); The calculation module, connected to the monitoring module, is used to calculate the total deformation angle of the bearing frame (7) based on the measured displacement data; The measurement result output module is connected to the position acquisition module and the calculation module respectively, and is used to compare the total deformation angle with the threshold and combine it with the position data to obtain the measurement result of the laser tracker turntable axis system.

[0008] In one embodiment of the present invention, the monitoring module includes at least one self-mixing interference displacement sensor, which is disposed in the area on both sides of the bearing frame (7) corresponding to the pitch drive bearing module.

[0009] In one embodiment of the present invention, the pitch drive bearing module includes a pitch drive spindle (3), a bearing (5), a bearing support seat (6), and a pitch driven shaft (9); wherein the pitch drive spindle (3) is connected to the bearing frame (7); the pitch drive spindle (3) and the pitch driven shaft (9) are connected by the bearing (5), and the bearing support seat (6) is provided on one side of the bearing (5).

[0010] In one embodiment of the present invention, the structure of the bearing frame (7) is an O-shaped structure, and the bearing support seat (6) is provided on both sides of the O-shaped structure; after the bearing support seat (6) is assembled into the O-shaped structure, the end jump and radial jump are controlled by dial gauge to make the axis of the mounting hole of the bearing support seat (6) coaxial with the axis of the pitch drive spindle (3).

[0011] In one embodiment of the present invention, the position acquisition module includes a photoelectric encoder code disk (8), which is disposed at the end of the pitch follower shaft (9) away from the pitch drive main shaft (3).

[0012] In one embodiment of the present invention, the pitch drive bearing module further includes a bearing inner frame (1) and a drive motor, wherein the bearing inner frame (1) is connected to the rotor of the drive motor.

[0013] Secondly, to solve the above-mentioned technical problems, the present invention provides a method for measuring the deformation of a laser tracker turntable shaft system, which is implemented using the aforementioned laser tracker turntable shaft system deformation measurement system, including: S1, drive the load-bearing frame (7) to perform pitching motion; S2. Real-time acquisition of position data of the turntable axis system of the laser tracker, and acquisition of measurement displacement data of the preset monitoring area of ​​the bearing frame (7); S3. Calculate the total deformation angle of the bearing frame based on the measured displacement data; S4. Compare the total deformation angle with the threshold, and combine it with the position data to obtain the measurement results of the laser tracker turntable axis system.

[0014] In one embodiment of the present invention, step S3, which involves calculating the total deformation angle of the bearing frame based on the measured displacement data, is as follows: The measured displacement data is split into true displacement components and scale error; The true displacement components are calculated by the difference between the Y coordinates of the front and rear measuring points within the same measuring channel; the sign of each true displacement component is determined according to the geometric positional relationship of the target measuring section in the preset monitoring area; and the expression corresponding to the measured displacement data is adjusted according to the sign. Based on the measured displacement data, calculate the end face rotation angle of the first region and the end face rotation angle of the target measurement section respectively; The total deformation angle at the target measurement section is obtained based on the expression, the end face rotation angle of the first region, and the end face rotation angle of the second region.

[0015] In one embodiment of the present invention, the expression for the total deformation angle is: ; in, Indicates the total deformation angle. Indicates the first One true displacement component Indicates the serial number of the self-mixed interferometric displacement sensor. This indicates the total number of self-mixed interferometric displacement sensors. Indicates the baseline length.

[0016] In one embodiment of the present invention, the method for collecting the measured displacement data of the preset monitoring area of ​​the bearing frame (7) in step S2 is as follows: a coordinate system is constructed using the target measurement section in the preset monitoring area as a geometric reference; according to the coordinate system, the measuring point group of the target measurement section is measured using the monitoring module to obtain the measured displacement data.

[0017] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: (1) The laser tracker turntable shaft deformation measurement system and method of the present invention constructs a complete and functionally integrated pitch shaft system through the coordinated arrangement and functional coupling of the inner frame, drive motor, pitch drive spindle, bearing, bearing support, load-bearing frame, photoelectric encoder disk, and pitch driven shaft. The monitoring module is integrated into the housing and can detect minute axial deformation of the load-bearing frame in real time during turntable operation, providing a structural basis and data support for the proposed axial runout detection method. This effectively overcomes the problems of traditional devices being large in size, complex in structure, difficult to integrate, and unable to monitor online in real time. The system of the present invention achieves a comprehensive improvement in accuracy, stability, environmental adaptability, and system integration in shaft deformation measurement. It not only provides a more reliable angle reference for the laser tracker but also significantly improves its operating efficiency and long-term stability.

[0018] (2) This invention directly collects local deformation and derives the total deformation angle through a geometric difference and rotation angle superposition algorithm. This design eliminates the complex optical assembly process and reduces the requirements for the quality of the reflective surface; at the same time, with the help of the optimized design of the sensor vibration isolation structure, the measurement system can effectively resist vibration interference and maintain high accuracy and high stability in complex environments. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Figure 1 This is a schematic diagram of a laser tracker turntable shaft deformation measurement system according to a preferred embodiment of the present invention; Figure 2This is a structural diagram of the pitch drive bearing module in a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the ranging principle of the self-mixing interferometric displacement sensor in a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the installation position of the self-mixing interference displacement sensor in a preferred embodiment of the present invention; Figure 5 This is a top view of the arrangement of a four-point self-mixing interferometric displacement sensor in a preferred embodiment of the present invention; Figure 6 This is a top-view diagram showing the deformation of the O-frame cross-section of the laser tracker's pitch axis system in a preferred embodiment of the present invention. Figure 7 This is a flowchart of a laser tracker turntable shaft deformation measurement method according to a preferred embodiment of the present invention.

[0021] Explanation of reference numerals in the accompanying drawings: 1. Inner frame; 2. Drive motor rotor; 3. Pitch drive spindle; 4. Housing; 5. Bearing; 6. Bearing support seat; 7. Bearing frame; 8. Photoelectric encoder disk; 9. Pitch driven shaft; 10. Self-mixing interference displacement sensor. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0023] Example 1: Reference Figures 1 to 2 As shown, an embodiment of the present invention provides a laser tracker turntable shaft deformation measurement system, comprising: The pitch drive load module has a built-in load frame 7; the pitch drive load module is used to drive the load frame 7 to perform pitch movement. The position acquisition module is used to acquire the position data of the laser tracker turntable axis system in real time; The monitoring module, connected to the pitch drive load module, is used to collect the measured displacement data of the preset monitoring area of ​​the load frame 7; The calculation module, connected to the monitoring module, is used to calculate the total deformation angle of the bearing frame 7 based on the measured displacement data; The measurement result output module is connected to the position acquisition module and the calculation module respectively. It is used to compare the total deformation angle with the threshold and combine it with the position data to obtain the measurement results of the laser tracker turntable axis system.

[0024] Specifically, refer to Figure 2As shown, the pitch drive load-bearing module also includes a load-bearing inner frame 1, a drive motor, a pitch drive main shaft 3, a bearing 5, a bearing support 6, a pitch driven shaft 9, and a housing 4. The load-bearing inner frame 1 is connected to the drive motor, which is connected to one end of the pitch drive main shaft 3. The other end of the pitch drive main shaft 3 is connected to the load-bearing frame 7. The pitch drive main shaft 3 and the pitch driven shaft 9 are connected via the bearing 5, and a bearing support 6 is provided on one side of the bearing 5.

[0025] Furthermore, the position acquisition module includes a photoelectric encoder code disk 8. The photoelectric encoder code disk 8 is located at the end of the pitch follower shaft 9 away from the pitch drive main shaft 3.

[0026] This invention discloses a laser tracker turntable shaft deformation measurement system. Addressing the problems of poor integration and real-time performance, large size, complex structure, difficulty in integration, and inability to monitor online in real time in existing technologies, this system constructs a complete and functionally integrated pitch shaft system through the coordinated arrangement and functional coupling of the inner frame 1, drive motor, pitch drive spindle 3, bearing 5, bearing support 6, support frame 7, photoelectric encoder disk 8, and pitch driven shaft 9. The monitoring module, integrated into the housing 4, can detect minute axial deformations of the support frame 7 and related components in real time during turntable operation, providing a structural foundation and data support for the proposed axial runout detection method. This effectively overcomes the problems of large size, complex structure, difficulty in integration, and inability to monitor online in real time in traditional devices. This system achieves a comprehensive improvement in accuracy, stability, environmental adaptability, and system integration in shaft deformation measurement. It not only provides a more reliable angular reference for the laser tracker but also significantly improves its operating efficiency and long-term stability. The system described in this invention provides solid technical support for online health monitoring and error compensation of high-precision measuring equipment. At the same time, it effectively solves the problems of weak measurement stability and anti-interference ability, susceptibility of single-point or single-sided measurement to local errors and environmental common-mode interference, lack of effective cancellation mechanism, poor adaptability to complex environments, reliance on high-precision optical assembly and reflective surface, and difficulty in long-term stable operation in industrial sites.

[0027] Specifically, the inner support frame 1 is located at the center of the pitch drive support module. As the core support component of the pitch axis system, it is internally connected to the rotor of the drive motor (i.e., drive motor rotor 2), providing power support for the pitch movement of the turntable. During operation, the inner support frame 1 not only bears the driving torque output by the motor but also maintains the stability of the overall structure, while serving as a reference benchmark for subsequent deformation measurements.

[0028] Furthermore, the inner frame 1 is a hollow structure with an axially penetrating cavity and hole system along the pitch axis. Its inner wall has a positioning stop and threaded ring, and bearing seat steps are formed on both sides to support and pre-tighten the pitch drive spindle 3. The stator of the drive motor is fixed to the bearing frame 7, and the rotor is rigidly connected to the pitch drive spindle 3 via a connecting sleeve. The spindle is supported by bearing support seats 6 on both sides and then connected to the bearing frame 7. Thus, the motor output torque acts on the inner frame 1 through the force transmission path of the rotor, spindle, and bearing frame. During operation, the inner frame 1 not only bears the driving torque and maintains overall rigidity but also serves as a reference for the assembly and deformation measurement of the pitch axis.

[0029] Specifically, the drive motor rotor 2 is connected to the bearing frame 7 via the pitch drive spindle 3. The pitch drive spindle 3, as the drive shaft, directly transmits the power output from the motor, enabling the bearing frame 7 and its related structures to pitch and rotate. As a crucial load-bearing and connecting component in the shaft system, the bearing frame 7 provides symmetrical geometric support for pitch movement. Furthermore, when subjected to load, its deformation directly reflects the axial deformation characteristics of the shaft system, thus becoming a key component for measurement and analysis in this invention.

[0030] Specifically, a precision bearing 5 and a bearing support 6 provide rotational support between the pitch drive spindle 3 and the pitch driven shaft 9. The bearing support 6 is mounted on the column holes on both sides of the support frame 7 and is assembled with the bearing 5 and the pitch driven shaft 9 using a pressure ring before being fixed to the support frame 7. The bearing 5 ensures smooth rotation and reduces the impact of friction and vibration on measurement accuracy. The bearing support 6 provides stable positioning and load-bearing for the bearing 5, ensuring that the pitch drive spindle 3 and the pitch driven shaft 9 remain coaxial during rotation, thereby effectively reducing the additional impact of axial error. A photoelectric encoder disk 8 is installed at the end of the pitch driven shaft 9. The photoelectric encoder disk 8 provides high-resolution angular position information, and combined with deformation detection of the support frame 7, it enables coordinated monitoring of angle and shaft deformation during pitch motion.

[0031] Specifically, the axial deformation detection of the laser tracker focuses on the bearing frame 7 as the main research object. The bearing frame 7 is located at the core of the turntable's pitch axis and is a crucial load-bearing and support structure between the pitch drive main shaft 3 and the pitch driven shaft 9. Since the bearing frame 7 directly bears the axial load and the inertial force during rotation, its deformation characteristics can accurately reflect the overall response of the entire pitch axis system under dynamic operation. Therefore, this embodiment of the invention preferably uses the local deformation of the bearing frame 7 as the measurement benchmark. By real-time monitoring of its cross-sectional deformation, the total axial deformation angle generated by the laser tracker turntable during pitch motion is derived.

[0032] Furthermore, regarding the structure of the support frame 7, an O-shaped structure is preferred in this embodiment of the invention. The inner or outer contour of the O-shaped structure is coaxially arranged with the axis of the pitch drive spindle 3. Specifically, from a structural perspective, the O-shaped support frame (referred to as the O-frame) possesses a natural symmetry advantage, forming a 360° stress distribution path without blind spots, making it the main support structure for the pitch axis system and measurement components. When the pitch drive spindle 3 transmits motor power to rotate the support frame 7, the O-shaped structure can evenly distribute the driving force and external load to the entire frame, avoiding structural deformation deviations caused by local stress concentration, and improving the stability of the axis system during pitch rotation. This is something that other symmetrical structures such as rings and frames cannot fully achieve. At the same time, the centroid of the O-shaped structure is easily and precisely coincident with the axis of the pitch drive spindle 3, which can minimize the generation of additional eccentric loads during rotation, thereby reducing the interference of non-axial deformation on the monitoring results and providing a more stable structural foundation for subsequent deformation measurement. From a monitoring function perspective, the axial deformation of the O-frame shows a good linear correlation with the overall axial deformation characteristics of the axis system. Because the distance from all parts of the O-frame to the axis is consistent, the deformation distribution on the end face of the frame is more uniform when subjected to axial load. Selecting the center of the end face, the edge stress concentration point, or the endpoint of the axis of symmetry as the preset monitoring area can more accurately reflect the overall axial deformation state of the shaft system. Compared to other symmetrical structures, the deformation signal of the O-frame is more stable and representative. Combined with the high-precision detection of the sensors in the monitoring module, the accuracy and reliability of the shaft system's axial deformation monitoring can be further improved, fully meeting the system's requirements for precise analysis of shaft deformation characteristics.

[0033] Furthermore, in this embodiment of the invention, bearing support seats 6 are provided on both sides of the O-type structure, and the common axis of the mounting holes of the bearing support seats 6 is the axis of the pitch drive spindle. After the bearing support seat 6 assembly is assembled into the O-type structure, the spindle axis is made coaxial with the common axis by controlling the end runout and radial runout using a dial indicator.

[0034] Specifically, the housing 4 serves as the structural outer shell, covering and protecting the entire shaft system and the pitch drive load-bearing module, while also providing an installation and fixing reference for the monitoring module. The monitoring module includes at least one self-mixing interferometric displacement sensor (SMI) 10, which is disposed in the area on both sides of the housing 4 of the pitch drive load-bearing module corresponding to the load-bearing frame 7.

[0035] This invention achieves precise capture of the dynamic characteristics of the pitch axis system by deploying self-mixed interferometric displacement sensors 10 on the housing 4, combined with an optimized structural support design for the core rotating component. Furthermore, this invention effectively eliminates the interference of instrument vibration on deformation measurement results through distributed data self-compensation processing. This self-compensation mechanism utilizes data collected by multiple self-mixed interferometric displacement sensors (SMI) 10 to correct errors caused by instrument vibration in real time, thereby significantly improving the accuracy and reliability of deformation measurement.

[0036] Specifically, refer to Figure 3 As shown in the figure, this is a schematic diagram of the ranging principle of the self-mixed interferometric displacement sensor 10. The symbols in the figure... This indicates the monitoring of photodiodes and their quantum efficiency. Indicates the output light power. This indicates the reflectivity of the laser's output surface (front cavity mirror). This represents the distance between the external target and the emitting surface of the semiconductor laser. The measurement system of the self-mixing interferometric displacement sensor 10 includes a semiconductor laser, a photodiode integrated within the semiconductor laser package, a collimating lens, and the external target to be measured. This structure can utilize the sensitivity of the semiconductor laser diode to the feedback light to achieve a direct correspondence between the displacement and the output signal, thereby completing high-precision micro-displacement detection. Specifically, the laser self-mixing of the self-mixing interferometric displacement sensor 10 refers to the fact that after the laser beam emitted from the laser is reflected by the target surface, part of the light is recoupled back into the laser resonant cavity, interfering with the optical field within the cavity, and thus self-modulating the power, frequency, and phase of the laser; the change in light intensity before and after this modulation is expressed as: (1); in, This indicates the initial frequency of the laser. This indicates the frequency of the laser after self-mixing interference; This indicates the time required for the laser to travel to and from the resonant cavity; The light feedback intensity coefficient represents the strength of the feedback light. This indicates the initial power of the laser. This indicates the power of the laser after self-mixing interference; Indicates the broadening factor. This represents the modulation depth (light intensity modulation coefficient). Therefore, according to formula (1), the phase change after interference is obtained as follows: This yields the displacement of the object's surface: (2); in, Indicates the initial laser wavelength; This indicates the laser wavelength after self-mixing interference; Round-trip time refers to the propagation time of a laser beam from inside the cavity to an external target, then being reflected back and re-entering the cavity. This represents the symbol for pi. Therefore, from formula (2), we get: (3).

[0037] Furthermore, It is a cycle of The function, assuming the optical feedback phase changes for each The displacement change of the external target is Then we can obtain Therefore, This means that for every displacement of the external target This corresponds to the output of a self-mixing interference fringe. Therefore, the displacement measurement accuracy of the self-mixing interference system is... It has the same measurement accuracy as traditional interferometry.

[0038] Furthermore, the phase in the self-mixed interferometry also carries information about the displacement direction. When an external target approaches the self-mixed interferometry displacement sensor 10, the optical path length decreases, and the interference phase increases accordingly; conversely, when the target moves away from the self-mixed interferometry displacement sensor 10, the optical path length increases, and the phase changes in the opposite direction. This positive and negative phase change over time is directly reflected in the shape of the output power fringes. Specifically, the fringes appear in an ascending order when the target approaches and a descending order when it moves away. The monotonicity and directionality of the phase ensure that the self-mixed interferometry can not only measure the magnitude of the displacement but also determine the direction of the target's motion. Traditional solutions often require additional optical structures (such as orthogonal interferometer arms or external phase modulation) to distinguish the displacement direction, while the self-mixed interferometry displacement sensor 10 can naturally reflect the direction information in the output signal by relying on the optical feedback effect within the laser cavity. This characteristic greatly simplifies the measurement system structure and improves the reliability of displacement and velocity measurements.

[0039] Furthermore, self-mixing interferometry exhibits extremely high sensitivity to feedback light. After the feedback light is incident on the resonant cavity, it interacts with the laser medium and is amplified. This allows for the acquisition of vibration signals with high signal-to-noise ratios for rough, non-matching measurement targets without the need for a target mirror, through phase changes. Compared to traditional methods, self-mixing interferometry displacement sensors offer significant advantages such as compact structure, simple optical path, ease of collimation and assembly, and low implementation cost. They provide high measurement resolution, achieving nanometer-level displacement sensitivity. Simultaneously, by eliminating complex external interferometer arms and beam splitters, this method exhibits strong robustness to environmental vibrations and optical path alignment errors, making it suitable for high-precision detection of minute deformations and runout errors in the pitch axis system of laser trackers.

[0040] Furthermore, referring to Figure 4As shown, this embodiment of the invention preferably uses four self-mixing interferometric displacement sensors 10, arranged in a symmetrical pattern. Specifically, they are installed on the front and rear sides of the housing 4, with one pair on each side, enabling synchronous acquisition of displacement signals caused by axial runout during pitch motion. It should be noted that, for clearer visualization of the internal structure, Figure 4 The right side of the outer casing is not shown, but the sensor is also mounted at the corresponding positions on the front and back of that side casing. This symmetrical layout design ensures the integrity and reliability of the measurement results, and effectively offsets common-mode errors introduced by overall translation or external interference, thereby significantly improving measurement accuracy.

[0041] Furthermore, referring to Figure 5 As shown, Figure 5 The image shows the top-down view of the specific installation position of the self-mixed interferometric displacement sensor 10. The four self-mixed interferometric displacement sensors 10 are evenly distributed at the four corners of the housing 4, corresponding to the front and rear, left and right areas of the pitch axis system, respectively. They can simultaneously monitor the minute deformation of the axis system in different directions, providing multi-point data support for the quantitative analysis of axial runout.

[0042] Furthermore, to ensure the signal stability of the self-mixing interferometric displacement sensor 10, this embodiment of the invention incorporates targeted vibration damping and anti-vibration measures at its connection surface with the housing 4. Specifically, a damping layer and an adhesive layer are added between the self-mixing interferometric displacement sensor 10 and the housing 4, thereby strengthening the connection stability and suppressing vibration interference through this dual structure. The specific installation steps for the damping layer and the adhesive layer are as follows: First, a layer of uniformly thick silicone rubber pad is pasted on the mounting surface of the housing 4 as a damping material. This material has a stable elastic modulus and damping performance, which can effectively absorb high-frequency vibrations and impacts generated by the external environment and shaft movement, reduce the signal noise introduced by vibration from the source, and ensure that the self-mixed interference displacement sensor 10 is not affected by hard impact interference during operation.

[0043] Secondly, after the damping material is bonded, the self-mixing interference displacement sensor 10 is fixed to the surface of the damping layer using epoxy structural adhesive. After the adhesive layer cures, it forms a stable bonding interface with low shrinkage and strong temperature resistance, ensuring that the sensor does not loosen or drift during long-term operation. At the same time, the bonding adopts a full contact method, so that the bottom surface of the sensor is completely bonded to the damping layer, which avoids local stress concentration and ensures uniform force distribution, thereby ensuring the stability of signal acquisition.

[0044] In this embodiment of the invention, the installation method described above enables the self-mixing interferometric displacement sensor 10 and the housing 4 to form a stable three-layer connection structure consisting of a damping layer, an adhesive layer, and the sensor itself. This structure provides excellent vibration isolation performance, effectively reducing the interference of environmental vibrations on the measurement signal, and ensures long-term fixed and stable operation of the sensor. Furthermore, combined with a four-point layout and symmetrical installation strategy, the system described in this embodiment of the invention achieves highly stable and highly sensitive axial runout measurement while maintaining a compact structure, laying a reliable structural foundation for subsequent monitoring and error compensation.

[0045] In actual operation, the axial runout of the pitch axis exhibits a combination of micro-periodic displacement and slow drift. The periodic component originates from the form and position error of the bearing 5 end face and uneven preload, which excites first, second, and higher harmonics per revolution of the pitch drive main shaft 3 and the pitch driven shaft 9, forming axial runout with a frequency locked to the shaft frequency. The drift component is induced by the torque pulsation of the drive motor 2 and continuous temperature rise. The thermo-elastic-load coupling effect causes the inner frame 1 to slowly expand and contract relative to the O-frame. The symmetrical structure of the O-frame amplifies both types of displacement proportionally and transmits them to the omnidirectional geometric center of the optical path, resulting in periodic offset and reference drift of the equivalent node in the axial direction, directly weakening the Abbe accuracy of the ranging system. Therefore, it is necessary to perform real-time, separable observation and quantification of the axial micro-deformation of the laser tracker.

[0046] Specifically, refer to Figure 6 As shown, self-mixed interferometric displacement sensors 10 are fixedly arranged on both sides of the O-frame through a damping layer and an adhesive layer, with one sensor on each side (front and back), for a total of four sensors. This symmetrical arrangement enables synchronous monitoring of the relative displacement changes of the O-frame cross-section in the front-back direction. Furthermore, thanks to the nanometer-level resolution of the sensors, it can accurately capture the minute deformations of the O-frame under axial load, providing reliable data support for subsequent angle calculations.

[0047] Furthermore, referring to Figure 6 The cross section shown is used as the geometric reference. Establish the coordinates (right-handed coordinates) in the first and fourth quadrants: The axis is vertically downward. The axis is horizontal to the left. The four measured displacements of the self-mixed interferometric displacement sensor 10 at two points before and after the measurement section are recorded as follows: ( Considering that the laser tracker's axis system and the O-frame share the same environment and base, the four test points of the O-frame are all subjected to almost equivalent, simultaneous, and unidirectional disturbances. Their projections on the y-axis are also unidirectional and equal, which is defined here as the scale error. .therefore Can be broken down into , These are the actual displacement components. The values ​​can be directly obtained from the two measurement points before and after the same channel. The calculation is performed by subtracting the coordinates of the points; the expression is as follows: (4); in, , and These are the coordinates of the initial cross section, the front measuring point, and the rear measuring point on the Y-axis, respectively.

[0048] Furthermore, based on positional relationships, we obtain The value is positive. If it is negative, then similarly we get The value is positive. The value is negative. Recorded in the order of top left, bottom left, top right, bottom right. , , , Substituting formula (4) into the equation, Represented as: (5).

[0049] Furthermore, the geometric distance between two measurement points is defined as the baseline length. Since the position of the self-mixing interferometric displacement sensor 10 does not change, the baseline length is... The value remains unchanged. In this embodiment, the displacement sign is set to positive, and the angle is approximated by a small-angle linear approximation. The end face rotation angle can be obtained from the displacement difference. Under small deformation conditions, the local rotation angle of the rigid body at the cross section can be given by the difference between the front and rear displacements / baseline, i.e. Therefore, the left and right end face corners are respectively and .in, and It is obtained from the following formula: (6); (7).

[0050] Furthermore, based on geometric relationships, the rotation angle of the left-side section... With right-side section angle The total deformation angle is obtained by direct superposition. Its expression is: (8).

[0051] Furthermore, the above definition is consistent with the analysis method of traditional dual autocollimators, ensuring the theoretical rationality of the measurement method. Unlike single-sided measurement, this embodiment of the invention utilizes bilateral symmetrical measurement, effectively avoiding errors introduced by single-sided measurement and ensuring the accuracy and stability of the results. This invention adopts its definition, defining the total deformation angle as the algebraic sum of the rotation angles of the left and right end faces, specifically expressed as: (9).

[0052] Furthermore, substituting formula (5) into formula (9), we obtain: (10); in, The terms are geometrically automatically canceled out, and the method inherently possesses the ability to cancel out overall drift. Therefore, if the pitch axis system experiences overall translation or minor vibration during operation, all self-mixed interferometric displacement sensors 10 will simultaneously record similar displacement changes. However, this embodiment of the invention uses a front-to-back differential calculation method, and this common-mode signal will automatically cancel out in the result, thereby ensuring that the calculated end-face rotation angle only represents bending and warping effects. Furthermore, since the sensors are arranged in pairs on the left and right sides, the left-right symmetry can further eliminate asymmetric disturbances caused by single-point installation errors or accidental noise.

[0053] In this embodiment of the invention, the total deformation angle It possesses the dual attributes of both geometric measurement and axis health criterion. Specifically, the total deformation angle... The numerical value directly reflects the coordinated accuracy of the pitch drive spindle 3, the pitch driven spindle 9, and the associated support components. When the total deformation angle... When the load is within the threshold range, it indicates that the shaft load distribution is uniform, the bearing preload is appropriate, and the assembly relationship is stable; once... Exceeding the threshold means that abnormal rigid body rotation occurs in the O-frame section. The root causes are often loose bearings, excessive clearance, or instantaneous overload. At this point, the shaft system has deviated from its statically determinate state. (Regarding the total deformation angle...) By implementing full-time calculations, feature capture and source tracing can be completed in the early stages of faults, enabling online assessment and diagnosis of the pitch axis system's operating quality, and providing real-time assurance for the high-precision and high-reliability operation of the laser tracker throughout its entire life cycle.

[0054] Further, the working steps of the laser tracker turntable shaft deformation measurement system described in this embodiment of the invention are as follows: First, the pitch drive bearing module is activated. The pitch drive bearing module drives the bearing frame 7 to perform pitch movement according to preset instructions. The position acquisition module synchronously acquires the position data of the laser tracker turntable shaft system in real time and transmits it to the measurement result output module. During the pitch movement of the bearing frame 7, the monitoring module continuously acquires the measured displacement data of the preset monitoring area and transmits it to the calculation module. After receiving the measured displacement data, the calculation module calculates the total deformation angle of the bearing frame 7 through a precise algorithm and transmits the result to the measurement result output module. The measurement result output module compares the total deformation angle with a preset threshold, combines it with the turntable shaft system position data, and generates and outputs the final measurement result.

[0055] Furthermore, it should be noted that the calculation module and the measurement result output module can be integrated within the controller. This controller is connected to both the position acquisition module and the monitoring module via communication connections, receiving displacement data from the position acquisition module and axis position data from the monitoring module. The controller processes the received data, compares it with preset thresholds, and ultimately outputs the measurement results of the laser tracker turntable axis system. This integrated design not only improves the overall system performance but also enhances the efficiency and accuracy of data processing.

[0056] The system described in this embodiment of the invention achieves real-time separation of axis deformation and attitude components by deploying a four-probe self-mixing interferometric array on the outer wall of the laser tracker turntable, combined with a front-to-back differential and left-to-right combined calculation method. This solution maintains arcsecond-level measurement accuracy while possessing the core advantages of miniaturization, easy integration, and online operation; compared with existing technologies, it achieves significant improvements in measurement accuracy, system stability, and environmental adaptability. Specific advantages are as follows: In terms of installation difficulty and on-site structural compatibility, the four-point self-mixing interferometric sensor micro-displacement array adopts an external wall attachment arrangement, combined with a compact connection structure of damping layer-adhesive layer-sensor. It does not occupy the internal space of the shaft system, does not require large-size reflectors and long optical paths, and is compatible with enclosed and structurally complex O-frame turntables. The assembly and adjustment steps are simplified, the positioning repeatability is high, and the on-site integration efficiency and maintainability are significantly improved.

[0057] In terms of error component identifiability and quantification, the cross-sectional rotation angle is reconstructed based on four-point symmetrical solution of front-to-back difference and left-to-right combination, realizing the decoupling of pitch attitude, bending deformation and overall drift. Under reasonable baseline setting and micron-level channel resolution, the angle resolution can reach the level of dual autocollimators, and the pitch axis axial runout component can be directly and stably quantitatively characterized.

[0058] In terms of environmental robustness and operational stability, the SMI's built-in light source has self-alignment characteristics. Combined with real-time quality control of stripe contrast / feedback factor and abnormal channel rejection, the multi-point redundancy design can effectively suppress common-mode vibration and slow drift. It does not require high-quality mirrors and long optical paths, and can achieve continuous, low-drift stable measurements even in industrial environments with dust, vibration and temperature fluctuations.

[0059] Regarding structural consistency acquisition and angle synchronization recording, this solution utilizes the structural characteristics of the laser tracker's master-slave axis and O-frame. Four SMI sensors are symmetrically deployed at the front and rear, and left and right sides of the housing. Using front-rear differential and left-right combinations, real-time acquisition and calculation of cross-sectional angle changes and local displacements during operation are performed, highlighting characteristic quantities related to axial runout. Overall harmonic disturbances are mitigated through symmetrical differential methods, ensuring data stability and comparability. This compact installation method meets the stable acquisition requirements for long-term operation.

[0060] Furthermore, compared to traditional methods using optical mirrors or autocollimators, the structural design of this invention offers advantages in both compactness and robustness. The SMI sensor is directly attached to the housing 4, eliminating the complex optical path assembly and adjustment process and reducing the processing requirements for the reflective surface. The optimized vibration damping design ensures reliable system operation under vibration conditions. The four-point symmetrical arrangement further enhances signal redundancy and anti-interference capabilities. This scheme enables real-time, high-precision capture of axial runout and deformation data during the pitch motion of the laser tracker turntable, providing solid technical support for subsequent error compensation and condition diagnosis.

[0061] This invention discloses a laser tracker turntable shaft deformation measurement system, used for detecting and analyzing axial deformation during the pitch motion of a laser tracker. In actual operation, laser trackers require high-precision angle measurements, and the axial runout and deformation of their turntable shaft system directly affect measurement accuracy and operational stability. Therefore, structurally arranging this shaft system and conducting real-time monitoring of axial deformation is of significant engineering importance.

[0062] Example 2: Reference Figure 7 As shown, this embodiment provides a method for measuring the deformation of the turntable shaft system of a laser tracker, which is implemented using the laser tracker turntable shaft system deformation measurement system described in Embodiment 1. The method includes, but is not limited to, the following steps: S1, drive the load-bearing frame 7 to perform pitching motion; S2. Real-time acquisition of position data of the turntable axis system of the laser tracker, and acquisition of measurement displacement data of the preset monitoring area of ​​the bearing frame 7; S3. Calculate the total deformation angle of the bearing frame 7 based on the measured displacement data; S4. Compare the total deformation angle with the threshold and combine it with the position data to obtain the measurement results of the laser tracker turntable axis system.

[0063] Specifically, in step S1, the drive motor drives the pitch drive spindle 3 to rotate, and the pitch drive spindle 3 drives the bearing frame 7 and the pitch driven shaft 9 to perform pitch movement.

[0064] Specifically, in step S2, the photoelectric encoder disk 8 is used to collect the position data of the laser tracker turntable axis system in real time, and the monitoring module is used to collect the measured displacement data of the preset monitoring area of ​​the bearing frame 7. The method for collecting the measured displacement data of the preset monitoring area of ​​the bearing frame 7 using the monitoring module is as follows: a coordinate system is constructed using the target measurement section in the preset monitoring area as the geometric reference; according to the coordinate system, the monitoring module is used to measure the measurement point group of the target measurement section to obtain the measured displacement data.

[0065] Specifically, in step S3, the step of calculating the total deformation angle of the bearing frame 7 based on the measured displacement data is as follows: S310. Decompose the measured displacement data into true displacement components. and scale error .

[0066] S320. Calculate each true displacement component by using the difference between the Y-coordinate of the previous measuring point and the Y-coordinate of the subsequent measuring point within the same measuring channel. Based on the geometric positional relationship of the target measurement section in the preset monitoring area, determine the positive and negative signs of each true displacement component; adjust the expression of the corresponding measured displacement data according to the positive and negative signs.

[0067] S330. Based on the measured displacement data, calculate the rotation angle of the first region end face of the target measurement section. Second region end face corner .

[0068] S340, According to the expression, the end face angle of the first region. Second region end face corner The total deformation angle at the target measurement section is obtained. Among them, the total deformation angle The expression is: (11); in, Indicates the first One true displacement component Indicates the serial number of the self-mixed interferometric displacement sensor. This indicates the total number of self-mixed interferometric displacement sensors. Indicates the baseline length.

[0069] It should be noted that formula (11) in this embodiment is a general expression, while formula (10) in Embodiment 1 is a specific example when the total number of self-mixed interferometric displacement sensors 10 is 4, corresponding to formula (11) Special circumstances.

[0070] In this embodiment, the inner frame 1, as the core load-bearing component, not only provides geometric symmetry support but also sensitively reflects the axial deformation characteristics of the pitch axis system during operation, making it a key area for monitoring and analysis. Four self-mixing interferometric displacement sensors 10 are installed symmetrically at the front, rear, left, and right sides of the housing 4, forming a four-point arrangement. This symmetrical arrangement ensures that the small local deformations of the O-frame can be acquired in real time from different orientations, and the total deformation angle is calculated through differential and superposition. The advantages of this structure are: firstly, it effectively offsets common-mode errors caused by overall external translation or environmental vibrations; secondly, it ensures the stability and integrity of the measurement results. A three-layer connection method—a damping layer, an adhesive layer, and the sensor itself—is used between the sensor and the housing. The silicone rubber gasket, as a damping layer, significantly reduces interference from high-frequency vibrations and impacts, ensuring stable operation of the sensor over long periods. SMI (Self-Mixing Interferometric Sensor) achieves displacement detection based on the semiconductor laser self-mixing interferometric effect. When the laser beam is collimated by a collimating lens and strikes the surface of the O-frame, part of the light is reflected and recoupled back into the laser cavity, generating an interference effect. The interference signal corresponds one-to-one with the displacement, thus achieving deformation detection with nanometer-level precision. By installing sensors at two points before and after the O-frame cross-section, the obtained displacement difference can be converted into a local rotation angle, which is then superimposed to obtain the total deformation angle.

[0071] This embodiment proposes a compact, online-implementable, and high-resolution error detection method to address the minute runout errors generated during the rotation of the shaft system in a laser tracker. This method focuses on the quantitative monitoring and error component identification of the dynamic deformation of the shaft system, aiming to solve the prominent problems of existing technologies in terms of detection accuracy, system integration, and environmental adaptability, as detailed below: Firstly, it adapts to complex structures and overcomes deployment limitations. The internal structure of the turntable's axis system is complex, making it difficult to adapt to traditional measurement methods. Existing axis system error measurements mostly rely on laser interferometers, autocollimators, or contact probes, requiring high-precision reflectors, long optical paths, or dedicated platforms, which cannot meet the non-contact online measurement requirements of enclosed O-frames. This embodiment adopts an embedded sensor deployment scheme, eliminating the dependence on optical reference reflective surfaces and adapting to the compact and non-removable structural characteristics of the laser tracker turntable, significantly improving on-site adaptability and deployment flexibility.

[0072] Secondly, it decouples error coupling to achieve precise quantification. Runout error and attitude disturbance are coupled, making it difficult to separate and quantify using traditional methods. During turntable operation, shaft runout caused by assembly errors or stress deformation often superimposes on the overall attitude. Existing methods based on single-point or two-point displacement sampling cannot distinguish between minute jumps caused by axial deflection and bearing misalignment, making measurements susceptible to interference. This implementation adopts a four-point symmetrical layout strategy, extracting axial angle and linear displacement changes through front-to-back differential and left-to-right combination, reconstructing the O-frame cross-section rotation angle and deformation, achieving independent extraction of runout error, and significantly improving measurement accuracy and resolution.

[0073] Third, it enhances environmental robustness and ensures stable operation. Existing measurement solutions are highly dependent on the environment and have poor robustness. In the complex environment of industrial sites, traditional measurement methods that rely on reflectors or long optical path structures are easily affected by factors such as vibration and assembly / adjustment deviations, making long-term stable operation difficult. This invention is based on the principle of self-mixing interferometry, with a compact sensor structure that does not require complex alignment and has good anti-speckle capability; at the same time, it cancels common-mode noise interference through a multi-point redundant sampling mechanism, significantly improving the robustness and long-term stability of the system's online operation.

[0074] Fourth, it optimizes error modeling to fit the characteristics of the equipment. There is a lack of dedicated methods adapted to the structural characteristics of laser trackers. The turntable of a laser tracker adopts a spindle-driven axis plus O-frame structure, possessing special motion characteristics such as multi-axis linkage and force closed loop, making it difficult for traditional measurement methods to accurately describe its runout mechanism. This invention combines the motion characteristics of the O-frame to construct an error modeling framework based on cross-sectional rotation angle reconstruction and angle amplification, enhancing the structural relevance and quantitative analysis capabilities of error identification.

[0075] Furthermore, compared to existing solutions that rely on optical mirrors or autocollimators, this embodiment uses a self-hybrid interferometric displacement sensor to directly acquire local deformation, and derives the total deformation angle through a geometric difference and rotation angle superposition algorithm. This method eliminates the complex optical assembly and adjustment process and reduces the requirements for the quality of the reflective surface; at the same time, thanks to the optimized design of the sensor's vibration isolation structure, it can effectively resist vibration interference and maintain high accuracy and stability even in complex environments. In summary, this invention provides an efficient, simple, and easily engineering-implementable technical path for monitoring the axial deformation of the pitch axis of a laser tracker.

[0076] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0077] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0078] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0080] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A laser tracker tacheometer axis deformation measurement system, characterized by, The method comprises the following steps: A pitch drive bearing module is internally provided with a bearing frame (7); the pitch drive bearing module is used to drive the bearing frame (7) to perform pitch movement; A position acquisition module is used to acquire position data of a laser tracker turntable shaft system in real time; A monitoring module is connected with the pitch drive bearing module and is used to acquire measurement displacement data of a preset monitoring area of the bearing frame (7); A calculation module is connected with the monitoring module and is used to calculate a total deformation angle of the bearing frame (7) according to the measurement displacement data; A measurement result output module is connected with the position acquisition module and the calculation module respectively, and is used to compare the total deformation angle with a threshold value and obtain a measurement result of the laser tracker turntable shaft system in combination with the position data.

2. The laser tracker turntable shafting deformation measurement system of claim 1, wherein, The monitoring module comprises at least one self-mixing interference displacement sensor, which is arranged in regions corresponding to both sides of the bearing frame (7) of the pitch drive bearing module.

3. The laser tracker turntable shafting deformation measurement system of claim 1, wherein, The pitch drive bearing module comprises a pitch drive main shaft (3), a bearing (5), a bearing support seat (6) and a pitch driven shaft (9); wherein the pitch drive main shaft (3) is connected with the bearing frame (7); the pitch drive main shaft (3) and the pitch driven shaft (9) are connected through the bearing (5), and one side of the bearing (5) is provided with the bearing support seat (6).

4. The laser tracker turntable shafting deformation measurement system of claim 3, wherein, The structure of the bearing frame (7) is an O-shaped structure, and the O-shaped structure is provided with the bearing support seat (6) on both sides; after the bearing support seat (6) is assembled to the O-shaped structure, the axis of the bearing support seat (6) mounting hole is coaxial with the axis of the pitch drive main shaft (3) by controlling end jump and diameter jump.

5. The laser tracker turntable shafting deformation measurement system of claim 3, wherein, The position acquisition module comprises an optical encoder code disc (8), which is arranged at the end of the pitch driven shaft (9) away from the pitch drive main shaft (3).

6. The laser tracker turntable shafting deformation measurement system of claim 1, wherein, The pitch drive bearing module further comprises a bearing inner frame (1) and a drive motor, and the bearing inner frame (1) is connected with the rotor of the drive motor.

7. A method for measuring the deformation of a laser tracker turntable shaft system, implemented by using a laser tracker turntable shaft system according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1, driving the bearing frame (7) to perform pitch movement; S2, acquiring position data of a laser tracker turntable shaft system in real time and acquiring measurement displacement data of a preset monitoring area of the bearing frame (7); S3, calculating a total deformation angle of the bearing frame according to the measurement displacement data; S4, comparing the total deformation angle with a threshold value and obtaining a measurement result of the laser tracker turntable shaft system in combination with the position data.

8. The method of claim 7, wherein, The step S3 of calculating the total deformation angle of the bearing frame according to the measurement displacement data comprises the following steps: The measurement displacement data is divided into real displacement components and scale errors; Each real displacement component is calculated by the difference between the Y coordinates of the front measuring point and the rear measuring point in the same measuring channel; The positive and negative signs of each real displacement component are determined according to the geometric position relationship of the target measurement section in the preset monitoring area; The expression of the measurement displacement data is adjusted according to the positive and negative signs. According to the measured displacement data, a first area end face rotation angle and a second area end face rotation angle of the target measurement section are respectively calculated; According to the expression, the first area end face rotation angle and the second area end face rotation angle, a total deformation angle at the target measurement section is obtained.

9. The method of claim 7 or 8, wherein, The expression of the total deformation angle is: ； wherein, denotes the total deformation angle, denotes the first real displacement component, denotes the second real displacement component, denotes the self-mixing interference displacement sensor index, denotes the total number of self-mixing interference displacement sensors, denotes the baseline length.

10. The method of claim 7, wherein, The method for collecting the measured displacement data of the preset monitoring area of the bearing frame (7) is: taking a target measurement section in the preset monitoring area as a geometric reference, a coordinate system is constructed; according to the coordinate system, a monitoring module is used to measure a measurement point group of the target measurement section, and measured displacement data is obtained.

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