A spindle dynamic error measurement system and method using piezoelectric loading to simulate cutting force

Abstract

The present invention discloses a spindle dynamic error measurement system and method for piezoelectric loading simulation of cutting force; the measurement system includes a main bearing mechanism, a loading simulation mechanism and an optical trajectory acquisition module. The main bearing mechanism includes a base shaft, a loading bearing structure, a target and a laser. A bearing ball head is fixed on the outer ring of the loading bearing structure. The loading simulation mechanism includes a thrust application component. The thrust application component is used to apply thrust to the bearing ball head on the loading bearing structure; the present invention applies stable axial and radial loads to the rotating spindle at the same time by sleeved on the spindle a bearing with a bearing ball head on the outer ring. In addition, the present invention adjusts the force direction of the loading simulation mechanism on the bearing ball head through a circular arc track, thereby accurately simulating cutting force loads in different directions, so that the measured spindle dynamic error is more consistent with the actual processing scenario, and improves the detection accuracy of the spindle dynamic error.

Description

Technical Field

[0001] The present invention belongs to the technical field of spindle rotation error measurement in precision measurement, and specifically relates to a spindle dynamic error measurement system and method for simulating cutting force by piezoelectric loading. Background Art

[0002] Machine tools, as one of the key indicators of a country's modern machining technology level, play a vital role in manufacturing. Currently, key sectors such as aerospace, electronics and information technology, shipbuilding and marine engineering, and automotive parts manufacturing in my country are requiring micro- and nano-level precision from high-end CNC machine tools, further highlighting the importance of machine tool error control.

[0003] Experimental studies have shown that in turning, spindle rotation error has a significant impact on the accuracy of machined parts, accounting for 30%-70% of all influencing factors. Ideal rotational motion only contains one degree of freedom, but actual rotational motion often has six degrees of freedom. Except for the rotational motion of the Z axis, all other degrees of freedom are error motions. The three error forms of error motion are radial rotation error, inclination error, and axial error. At present, most of the research on the above three error forms belongs to theoretical analysis, simulation prediction and precision detection based on no-load state. The spindle rotation accuracy obtained from the research is difficult to reflect the actual rotation accuracy of the machine tool spindle under real cutting conditions. There are few studies that combine experiments to consider influencing factors such as speed, temperature rise, workpiece preload, and external load. Therefore, it is necessary to measure the dynamic error of the spindle loaded with simulated cutting force.

[0004] Currently, using machine vision to detect dynamic spindle errors under load generally requires multiple force-applying devices. Changing the force direction and angle requires resetting the detection platform, which can lead to errors in the test results. Furthermore, the force-applying device that applies the simulated axial load often obscures the spindle's end face during operation, making it difficult to capture the laser light trajectory emitted from the spindle end face. This poses a challenge to detecting spindle radial rotation errors using machine vision. Summary of the Invention

[0005] The purpose of the present invention is to provide a spindle dynamic error measurement system and method that simulates cutting force with piezoelectric loading, which can simultaneously simulate the radial load and axial load on the spindle during cutting through a single force application point, thereby realizing accurate detection of the dynamic error of the spindle under working conditions.

[0006] In a first aspect, the present invention provides a spindle dynamic error measurement system for piezoelectric loading simulation of cutting force, which includes a main body bearing mechanism, a loading simulation mechanism and an optical trajectory acquisition module. The main body bearing mechanism includes a base shaft, a loading bearing structure, a target device and a laser. The base shaft is used to connect the spindle to be measured. The inner ring of the loading bearing structure is installed on the base shaft. A bearing ball head is fixed on the outer ring of the loading bearing structure. The laser is installed on the base shaft through the target device. The laser emitted by the laser is eccentrically set relative to the axis of the base shaft. The optical trajectory acquisition module is used to collect the optical trajectory of the laser emitted by the laser as it rotates with the base shaft.

[0007] The loading simulation mechanism includes a thrust applying assembly for applying thrust to the bearing ball head on the loading bearing structure; the thrust applied by the thrust applying assembly intersects with the axis of the base shaft and the angle is adjustable.

[0008] Preferably, the loading simulation mechanism includes an arc guide rail, a sliding assembly, a height adjustment assembly, and a thrust application assembly. The sliding assembly is slidably connected to the arc guide rail; the center of the arc guide rail and the center of the ball bearing the ball head are coaxially aligned. The thrust application assembly is mounted on the slider body via the height adjustment assembly.

[0009] Preferably, the height adjustment assembly includes an adjustment frame and a base. The adjustment frame and the base are slidably connected in the vertical direction and can be locked at different positions. The thrust application assembly includes a force sensor, a guide support and a piezoelectric driver; the guide support is fixed on the adjustment frame. The piezoelectric driver is mounted on the guide support. The axis of the piezoelectric driver intersects perpendicularly with the vertical axis passing through the center of the circular arc guide rail. The force sensor is fixed on the adjustment frame and is used to detect the thrust output by the piezoelectric driver. During operation, the end of the piezoelectric driver rests against the load-bearing ball head on the loading bearing structure.

[0010] Preferably, the sliding assembly includes a steering block, rollers, a slider body, and a rotating shaft. The middle portions of the two steering blocks and two different locations on the bottom surface of the slider body respectively form a rotating pair. Two rollers are rotatably connected to both ends of the bottom surface of each steering block. The two rollers on the same steering block are respectively in rolling connection with opposite sides of the circular arc guide rail.

[0011] Preferably, the laser is mounted in a mounting groove in the middle of the outer end surface of the target. A silicon wafer is mounted at the opening of the mounting groove. A light-transmitting hole is formed in the silicon wafer. The axis of the light-transmitting hole is parallel to the axis of the base axis and the spacing is 5 μm to 15 μm.

[0012] Preferably, the main bearing mechanism further includes a mounting base; the basic shaft is a stepped shaft; the loading bearing structure and the mounting base are sequentially arranged and sleeved on the small-diameter shaft section of the basic shaft in a direction away from the stepped surface.

[0013] Preferably, the main body supporting mechanism further includes an elastic washer; the elastic washer is arranged between the inner ring of the loading bearing structure and the stepped surface of the base shaft.

[0014] Preferably, the load-bearing ball head is fixed to the outer circumferential surface of the outer ring of the loading bearing structure through a connecting rod.

[0015] In a second aspect, the present invention provides a spindle dynamic error measurement method using the aforementioned spindle dynamic error measurement system; the spindle dynamic error measurement method comprises the following steps:

[0016] Step 1: Fix the main bearing mechanism to the main shaft to be measured and adjust the coaxiality; adjust the height of the thrust applying assembly through the height adjustment assembly so that the thrust applying assembly rests against the bearing ball head on the loading bearing structure.

[0017] Step 2: Adjust the position of the sliding assembly on the arc guide rail so that the thrust direction applied by the thrust applying assembly to the load-bearing ball head is consistent with the direction of the cutting force applied during the operation of the spindle.

[0018] Step 3: The main shaft drives the main bearing mechanism to rotate, and the thrust applying component applies a thrust corresponding to the cutting force to the bearing ball head; the light trajectory acquisition module is used to acquire the light trajectory of the emitted laser during the rotation of the main bearing mechanism.

[0019] Step 4: Calculate the dynamic error of the spindle under actual cutting force based on the light trajectory.

[0020] Preferably, the dynamic error measured in step 4 is the spindle radial rotation error; the process of obtaining the spindle radial rotation error is:

[0021] (1) According to the coordinates of each sampling point on the light trajectory, calculate the fitting center and fitting radius of the light trajectory.

[0022] (2) The difference between the distance from each sampling point to the center of the fitting circle and the fitting radius is taken as the radial error of the sampling point; the extreme difference between the radial errors of all sampling points is taken as the radial rotation error of the spindle.

[0023] The present invention has the following beneficial effects:

[0024] 1. By placing a bearing with a load-bearing ball head on the outer ring of the spindle, the present invention applies stable axial and radial loads to the rotating spindle using only one force application point, thereby accurately simulating the cutting force load on the spindle during the cutting process, making the measured spindle dynamic error more consistent with the actual processing scenario.

[0025] 2. Based on the characteristic that the load-bearing ball head can bear thrusts in different directions, the present invention adjusts the force direction of the load-bearing ball head through the arc-shaped track adjustment loading simulation mechanism, thereby being able to adjust the ratio between the radial load and the axial load, more realistically simulating the cutting force load on the spindle during actual cutting, and improving the detection accuracy of the dynamic error of the spindle.

[0026] 3. This invention incorporates a height adjustment assembly within the loading simulation mechanism. By adjusting the height of the thrust-applying assembly, the force is precisely directed through the spindle axis, ensuring that the applied thrust is fully decomposed into radial and axial forces. Furthermore, the height adjustment of the thrust-applying assembly allows the invention to accommodate spindles of varying models and specifications. Furthermore, the height adjustment assembly utilizes an adjustable waist-hole connection, making the adjustment and fixation process quick and easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall structure of Example 1 of the present invention.

[0028] Figure 2 Schematic diagram of the structure of the loading simulation mechanism in Example 1 of the present invention.

[0029] Figure 3 Schematic diagram of the sliding connection between the arc guide rail and the sliding assembly in Example 1 of the present invention.

[0030] Figure 4 This is a schematic structural diagram of the arc guide rail in Example 1 of the present invention.

[0031] Figure 5 Schematic diagram of the relative positions of the main body supporting mechanism and the light trajectory acquisition module in Example 1 of the present invention.

[0032] Figure 6 This is a diagram showing the principle of measuring the radial rotation error of the spindle in Example 2 of the present invention.

[0033] Description of the drawings: 1. Arc guide rail; 2. Steering block; 3. Roller; 4. Slider body; 5. Rotating shaft; 6. Base; 7. Adjustment frame; 8. Force sensor; 9. Guide support; 10. Piezoelectric actuator; 11. Industrial camera; 12. Telecentric lens; 13. Measured spindle; 14. Base shaft; 15. Elastic retaining ring; 16. Loading bearing structure; 17. Mounting base; 18. Target; 19. Infrared laser; 20. Silicon wafer. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings.

[0035] Example 1

[0036] like Figure 1As shown, a spindle dynamic error measurement system with piezoelectric loading simulating cutting force includes a main body bearing mechanism, a loading simulation mechanism and an optical trajectory acquisition module.

[0037] The main support structure includes a base shaft 14, an elastic washer 15, a loading bearing structure 16, a mounting base 17, a target 18, a laser 19, and a silicon wafer 20. The laser 19 is mounted in a mounting groove in the middle of the outer end surface of the target 18. The silicon wafer 20 is mounted at the opening of the mounting groove. A light-transmitting hole is provided in the silicon wafer 20. The laser light emitted by the laser 19 through the light-transmitting hole does not coincide with the axis of the base shaft 14, but is separated by a distance of 10 μm.

[0038] The base shaft 14 is used to connect to the main shaft. The base shaft 14 is a stepped shaft, with a loading bearing structure 16 and a mounting base 17 mounted on the smaller diameter section, arranged in sequence away from the stepped surface. The mounting base 17 is fastened to the base shaft 14 via threads. The elastic washer 15 is positioned between the inner ring of the loading bearing structure 16 and the stepped surface of the base shaft 8. The loading bearing structure 16 comprises an inner ring, rollers, an outer ring, and a load-bearing ball head. The inner and outer rings form a revolving pair via multiple rollers. A load-bearing ball head is connected to the outer circumference of the outer ring via a connecting rod. The outer ring, connecting rod, and load-bearing ball head are integrally molded. The loading bearing structure 16 remains axially fixed under the restraint of the elastic washer 15 and mounting base 17 to prevent axial displacement.

[0039] like Figure 2 As shown, the loading simulation mechanism is used to apply radial load and axial load to the bearing ball head on the base shaft 14, and can adjust the ratio of radial load to axial load by adjusting the force application angle. The loading simulation mechanism includes an arc guide rail 1, a sliding assembly, a height adjustment assembly and a thrust application assembly. The arc guide rail 1 is fixed on the frame; the center of the bearing ball head and the center of the arc guide rail 1 are on the same vertical axis. The sliding assembly is slidably connected to the arc guide rail 1; the thrust application assembly is installed on the slider body 4 through the height adjustment assembly. The height adjustment assembly is used to adjust the height of the thrust application assembly and lock it so that the axis of the thrust application assembly passes through the center of the bearing ball head to ensure that the force applied by the thrust application assembly to the bearing ball head can be completely decomposed into the axial component and radial component on the measured spindle.

[0040] like Figure 3 and Figure 4As shown, the sliding assembly includes a steering block 2, a roller 3, a slider body 4, and a rotating shaft 5. The middle portion of the two steering blocks 2 and two different positions on the bottom surface of the slider body 4 respectively form a rotating pair. Two rollers 3 are rotatably connected to both ends of the bottom surface of the two steering blocks 2. The two rollers 3 on the same steering block 2 contact the opposite sides of the circular arc guide 1, forming a rolling connection, so that the sliding assembly can slide on the circular arc guide 1 with low resistance, so that the force F applied by the piezoelectric driver 10 to the loading bearing structure 16 a The angle between the main shaft and the main shaft can be adjusted within the range of 0° to 90°.

[0041] In some embodiments, the arc guide rail 1 , the steering block 2 , the slider body 4 , the base 6 , the adjustment frame 7 , and the guide support 9 are made of Invar.

[0042] In some embodiments, the outer shell material of the target device 18 is polyoxymethylene, which ensures that the target is light in weight and the internal laser circuit does not form a loop with the target device 18 .

[0043] The height adjustment assembly includes an adjustment frame 7 and a base 6. The adjustment frame 7 and base 6 are vertically slidably connected and can be locked with screws. In some embodiments, the adjustment frame 7 and base 6 are connected via an adjustable waist hole to enable vertical adjustment and locking, thereby ensuring the alignment of the piezoelectric actuator 10 with the base shaft 14.

[0044] The thrust application assembly includes a force sensor 8, a guide support 9, and a piezoelectric actuator 10. The force sensor 8 is fixed in a mounting groove at the top of the adjustment frame 7; the guide support 9 is fixed to the adjustment frame 7. The piezoelectric actuator 10 is mounted on the clamping guide support 9, with its tail end abutting against the force sensor 8. The force sensor 8 is used to detect the thrust output by the piezoelectric actuator 10. The axis of the piezoelectric actuator 10 intersects perpendicularly with the vertical axis passing through the center of the circular arc guide rail 1.

[0045] By utilizing the piezoelectric driver 10 , this embodiment can more realistically simulate all loads that the spindle is subjected to during an actual cutting process, and the piezoelectric driver 10 has high loading accuracy, high stability, and good dynamic performance.

[0046] like Figure 5 As shown, the light trajectory acquisition module includes an industrial camera 11 and a telecentric lens 12; the telecentric lens 12 is mounted on the lens of the industrial camera 11 and faces the target 1. This embodiment uses a trajectory tracking method that records light trajectory with an industrial camera, simplifying the consideration of vibration displacement required by traditional displacement sensors. This method is sensitive to the spindle's rotation direction, and the light trajectory represents the spindle's radial rotation error, making error measurement simpler.

[0047] Example 2

[0048] A spindle dynamic error measurement method uses the spindle dynamic error measurement system with piezoelectric loading simulating cutting force described in Example 1.

[0049] The spindle dynamic error measurement method comprises the following steps:

[0050] Step 1: Fix the arc guide rail 1 on the vibration isolation table, make sure that the center of the slide rail and the center of the standard sphere of the loading bearing structure 16 are on the same vertical axis, install rollers 3 at both ends of the steering block 2, and connect them to the slider body 4 with a rotating shaft 5 to ensure that when the slider body 4 moves in the arc guide rail 1, the steering block 2 can rotate and adjust the spacing between the rollers 3. Install the piezoelectric driver 10 into the piezoelectric driver guide support 9, and fix the guide support 9 and the force sensor 8 to the adjustment frame 7 with screws to ensure that the piezoelectric driver 10 will not deflect when subjected to force. Use the adjustable waist hole to connect the upper and lower adjustment frames 7 to ensure that the piezoelectric driver 10 is strictly aligned with the bearing 16. After alignment, fix it to the base 6 with screws and install the base on the slider body 4.

[0051] Step 2: Install an infrared laser 19 into the target device 18, and place a silicon wafer 20 with a fine diffraction pinhole in front of the laser, and fix it with a spring washer to ensure that when the main shaft 13 rotates, the laser beam emitted by the laser 19 through the fine diffraction pinhole produces an ideal spherical wave light trajectory with an eccentricity.

[0052] Step three, fix the basic shaft 14 to the measured main shaft 13 with countersunk screws. Pay attention to screwing in the countersunk screws diagonally during installation. After fixing the basic shaft 14, install the shaft elastic washer 15 to ensure its axial fixation, and install the preheated loading bearing structure 16. After the loading bearing structure 16 cools down, screw in the hydraulic nut. After a period of pressure maintenance, the gap of the loading bearing structure 16 is eliminated. At this time, unscrew the hydraulic nut, fix the target 18 on the mounting base 17 with the countersunk screws, and screw the mounting base to the basic shaft 14. At this time, the main bearing mechanism is installed.

[0053] Step 4. After the main bearing mechanism is installed, adjust the installation eccentricity by using a micrometer. Use a rubber hammer to tap the bottom of the target 18 to change the installation eccentricity. The adjustment process is as follows: Maintain appropriate preload when installing the main bearing mechanism, and leave a certain amount of feed margin for the screws so that tapping can move the target installation eccentricity. Lightly press the micrometer against the outer circumference of the target 18 to ensure that the micrometer reading does not exceed the micrometer range when the main shaft is rotated. Slowly rotate the main shaft 13 to find the maximum reading of the micrometer. Gently tap the target at the corresponding position of the micrometer contact to reduce the micrometer reading appropriately; slowly rotate the main shaft 13 again to find the maximum reading of the micrometer again. Similarly, tap the target 18 to reduce the reading. Repeat the above operation to minimize the fluctuation of the micrometer data. Finally, after repeated adjustments, the micrometer data range is within 2.6μm. At this point, the target eccentricity adjustment is completed. Tighten the screws and the target is installed.

[0054] Step 5. After adjusting the height of the piezoelectric driver 10, use the piezoelectric driver 10 to provide a loading simulated cutting force to the load-bearing ball head on the loading bearing structure 16; then, control the spindle 13 to start rotating. At this time, the main bearing mechanism rotates with the spindle 13, and the target device 18 generates a light track with an eccentricity of 10μm; adjust the exposure time of the industrial camera 11 synchronously with the rotation speed of the spindle 13, and magnify the image through the telecentric lens 12 to ensure that the camera 11 records the light track of the spindle 13 for one rotation, and obtain the spindle radial error through image processing and calculation. At the same time, the force sensor 8 collects the size of the simulated cutting force provided by the piezoelectric driver 10 when the spindle 13 rotates, and explores the influence of the simulated cutting force on the dynamic error of the spindle.

[0055] This embodiment provides an example of calculating the spindle radial rotation error as follows:

[0056] like Figure 6 As shown, the light trajectory measured by the camera 11 is collected; the coordinate data of the light trajectory is analyzed by the least squares circle to solve the coordinates of the center of the light trajectory; the obtained center coordinates are used as the main shaft rotation axis to solve the roundness error and then evaluate the main shaft radial rotation error. The coordinate positions of the n sampling points on the light trajectory constitute the coordinate set P, P = [x i ,y i ], i=1,2,...,n; n is the number of sampling points. Establish the objective function M(a,b,c):

[0057]

[0058] In the formula, a, b, and c are three undetermined parameters that need to be solved later.

[0059] Taking the partial derivative of the function M(a,b,c) and setting it to 0, we get the following system of equations:

[0060]

[0061] Solve to get the parameters a, b, and c. The coordinates of the center of the least squares circle (X0, Y0) can be expressed by the parameters a, b, and c:

[0062]

[0063] The radius of the least squares circle R0 is:

[0064]

[0065] Calculate the distance R between the coordinates of each sampling point in the coordinate set P and the center of the least squares circle (X0, Y0) i as follows:

[0066]

[0067] Calculate the spindle radial runout peak value E peak and valley value E valley :

[0068]

[0069] Among them, E i is the radial rotation error of the sampling point, and its expression is E i =R i -R0.

[0070] Calculate the radial rotation error value E of the trajectory through the range round as follows:

[0071] E round =E peak -E valley (7)

[0072] The obtained radial rotation error value E round It is the radial rotation error of the measured spindle under the condition of cutting force.

Claims

1. A spindle dynamic error measurement system for simulating cutting forces using piezoelectric loading, comprising a main bearing mechanism and an optical trajectory acquisition module; characterized in that: It also includes a loading simulation mechanism; the main bearing mechanism includes a base shaft (14), a loading bearing structure (16), a target (18) and a laser (19); the base shaft (14) is used to connect to the main shaft to be measured; the inner ring of the loading bearing structure (16) is installed on the base shaft (14); a bearing ball head is fixed on the outer ring of the loading bearing structure (16); the laser (19) is installed on the base shaft (14) through the target (18); the laser emitted by the laser (19) is eccentrically arranged relative to the axis of the base shaft (14); the light track acquisition module is used to acquire the light track of the laser emitted by the laser (19) rotating with the base shaft (14); the loading simulation mechanism includes an arc guide rail (1), a sliding assembly, a height adjustment assembly and a thrust application assembly; the sliding assembly is slidably connected to the arc guide rail (1); the center of the arc guide rail (1) and the center of the ball head are on the same vertical axis; the thrust application assembly is installed on the sliding assembly through the height adjustment assembly; The thrust applying assembly is used to apply thrust to the bearing ball head on the loading bearing structure (16); the thrust direction applied by the thrust applying assembly intersects with the axis of the base shaft (14) and the angle is adjustable; The thrust applying assembly comprises a force sensor (8), a guide support (9) and a piezoelectric driver (10); the piezoelectric driver (10) is mounted on the guide support (9); the axis of the piezoelectric driver (10) intersects perpendicularly with a vertical axis passing through the center of the circular arc guide rail (1); the force sensor (8) is used to detect the thrust output by the piezoelectric driver (10); during operation, the end of the piezoelectric driver (10) abuts against the bearing ball head on the loading bearing structure (16).

2. The spindle dynamic error measurement system with piezoelectric loading and cutting force simulation according to claim 1 is characterized in that: The height adjustment assembly comprises an adjustment frame (7) and a base (6); the adjustment frame (7) and the base (6) are slidably connected along the vertical direction and can be locked at different positions; the guide support (9) is fixed on the adjustment frame (7); and the force sensor (8) is fixed on the adjustment frame (7).

3. The spindle dynamic error measurement system with piezoelectric loading and cutting force simulation according to claim 1 is characterized in that: The sliding assembly comprises a steering block (2), a roller (3), a slider body (4) and a rotating shaft (5); the middle parts of the two steering blocks (2) and two different positions of the bottom surface of the slider body (4) respectively constitute a rotating pair; both ends of the bottom surface of the two steering blocks (2) are rotatably connected to two rollers (3); the two rollers (3) on the same steering block (2) are respectively rollingly connected to the opposite sides of the circular arc guide rail (1).

4. The spindle dynamic error measurement system with piezoelectric loading and cutting force simulation according to claim 1 is characterized in that: The laser (19) is installed in a mounting groove in the middle of the outer end surface of the target device (18); a silicon chip (20) is installed at the opening of the mounting groove; a light-transmitting hole is opened on the silicon chip (20); the axis of the light-transmitting hole and the axis of the base axis (14) are parallel to each other and are spaced apart.

5. The spindle dynamic error measurement system with piezoelectric loading and cutting force simulation according to claim 1 is characterized in that: The main body bearing mechanism further includes a mounting base (17); the basic shaft (14) is a stepped shaft; the loading bearing structure (16) and the mounting base (17) are sequentially arranged and sleeved on the small-diameter shaft section of the basic shaft (14) in a direction away from the stepped surface.

6. The spindle dynamic error measurement system using piezoelectric loading to simulate cutting force according to claim 5, characterized in that: The main body bearing mechanism further comprises an elastic washer (15); the elastic washer (15) is arranged between the inner ring of the loading bearing structure (16) and the stepped surface of the base shaft (8).

7. The spindle dynamic error measurement system with piezoelectric loading and cutting force simulation according to claim 1 is characterized by: The bearing ball head is fixed to the outer circumferential surface of the outer ring of the loading bearing structure (16) via a connecting rod.

8. A method for measuring spindle dynamic error, characterized by: Using the spindle dynamic error measurement system as claimed in claim 1; the spindle dynamic error measurement method comprises the following steps: Step 1: fix the main bearing mechanism to the main shaft to be measured and adjust the coaxiality; adjust the height of the thrust applying assembly through the height adjustment assembly so that the thrust applying assembly abuts against the bearing ball head on the loading bearing structure (16); Step 2: Adjust the position of the sliding assembly on the arc guide rail (1) so that the thrust direction applied by the thrust applying assembly to the bearing ball head is consistent with the direction of the cutting force applied during the operation of the spindle; Step 3: The main shaft drives the main bearing mechanism to rotate, and the thrust applying component applies a thrust corresponding to the cutting force to the bearing ball head; the light trajectory acquisition module is used to acquire the light trajectory of the laser emitted during the rotation of the main bearing mechanism; Step 4: Calculate the dynamic error of the spindle under actual cutting force based on the light trajectory.

9. The method for measuring the dynamic error of a main spindle according to claim 8, characterized in that: The dynamic error measured in step 4 is the spindle radial rotation error; the process of obtaining the spindle radial rotation error is: Step (1) Calculate the fitting center and fitting radius of the light trajectory according to the coordinates of each sampling point on the light trajectory; Step (2) takes the difference between the distance from each sampling point to the center of the fitting circle and the fitting radius as the radial error of the sampling point; and takes the extreme difference between the radial errors of all sampling points as the spindle radial rotation error of the spindle.

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