Laser scanning long axis straight line detection device based on reference straight line

Abstract

The present invention relates to the field of laser scanning long axis straightness detection devices based on a reference straight line, and in particular to a laser scanning long axis straightness detection device and method based on a reference straight line. The invention aims to solve the problems in the prior art of difficulty in measuring long axis workpieces and low accuracy due to lack of reference objects during the measurement process. The present invention includes a mounting frame, and workpiece clamping mechanisms are fixedly installed on both sides of the mounting frame. The workpiece clamping mechanisms include a head end clamping seat and a tail end clamping seat. Workpiece mounting pins are coaxially arranged on the mounting surfaces opposite to the head end clamping seat and the tail end clamping seat, and an auxiliary reference object parallel to the main axis is arranged between the clamping mechanisms; a non-contact measuring mechanism is installed in a direction perpendicular to the main axis of the workpiece; and a driving mechanism is also installed on the mounting frame to drive the workpiece to rotate along its central axis. The advantages are: the workpiece is firmly fixed, the measurement is accurate, the measurement of the long axis accuracy data can be achieved by adjusting the relevant components, and the measured data has good continuity.

Description

Technical Field

[0001] The present invention relates to the field of long-axis straight line detection devices, in particular to a laser scanning long-axis straight line detection device based on a reference straight line. Background Art

[0002] Bushing workpieces, often referring to rotating parts, serve as shafts when they have mating parts on the outside, and as holes when they have mating parts on the inside. These are collectively referred to as bushing parts. Dimensional accuracy measurements for these workpieces often focus on straightness and roundness, as these two accuracy metrics often directly reflect the workpiece's scrap rate. Therefore, the measurement process for bushing workpieces is particularly important.

[0003] However, in the existing technology, for long-axis workpieces, due to their large length, difficulty in fixing, and tendency to bend, the measurement of sleeve-type workpieces is difficult. At the same time, since the length of the fixing table for clamping the parts must also be long enough, the accuracy of the reference datum may not be high enough. When the accuracy of the reference datum is low, it is even more difficult to ensure the measurement accuracy. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem in the prior art that the measurement accuracy of long-axis workpieces is low and difficult to meet the requirements.

[0005] The specific scheme of the present invention is:

[0006] It includes a base slidably mounted on a bracket, and workpiece clamping mechanisms are fixedly mounted on both sides of the mounting frame, the workpiece clamping mechanisms include a head end clamping seat and a tail end clamping seat, workpiece mounting thimbles are coaxially arranged on the mounting surfaces opposite to the head end clamping seat and the tail end clamping seat, and an auxiliary reference object parallel to the main axis is arranged between the workpiece clamping mechanisms; a non-contact measuring mechanism is installed in the direction perpendicular to the main axis of the workpiece to be measured; a driving mechanism for driving the workpiece to rotate along its central axis is also installed on the sliding base, a locking handle is respectively provided on the head end clamping seat and the tail end clamping seat, and a top displacement adjustment handle is provided on the tail end clamping seat.

[0007] The auxiliary reference object includes a pull line with two ends respectively located on the clamping seats at the two ends, and a tension maintaining mechanism is connected to the pull line.

[0008] The tension maintaining mechanism includes a wire pulling wheel arranged at both ends of the wire pulling wheel, the wire pulling wheel is installed inside the head end clamping seat and the tail end clamping seat, the wire pulling outlet extends outward, and a coil spring is installed on the wheel axle of the wire pulling wheel to drive the wheel body to reset.

[0009] The auxiliary reference objects include a set of 0-grade blade rulers arranged directly below the workpiece to be measured.

[0010] The base includes a straight line slide rail, the head end clamping seat is fixed on the straight line slide rail, the tail end clamping seat is slidably installed on the straight line slide rail, the driving mechanism includes a clamping pin installed on the head end clamping seat and a driving motor that drives the clamping pin to rotate, and a transmission belt is connected between the driving motor and the chuck.

[0011] The non-contact measurement mechanism includes a laser scanner, which includes a transmitting end box and a receiving end box located at both ends of the workpiece to be measured. A rotating polygonal reflector, a lens group and a laser transmitter are provided in the transmitting end box. A receiving lens is provided in the receiving end box. A photoelectric tube is provided at the focus of the receiving lens. The lens group includes a group of concave lenses and convex lenses that aggregate scattered light into parallel light.

[0012] The tail end clamping seat is provided with a positioning hand wheel for adjusting the position of the clamping needle at the tail end.

[0013] The base is also provided with a power mechanism for driving the non-contact measuring mechanism to move. The power mechanism includes a moving motor and a moving belt driven by the moving motor. The bottom of the non-contact measuring mechanism is installed on the moving belt via a slider.

[0014] A method for measuring a long-axis workpiece, using the above-mentioned measuring device, comprises the following steps:

[0015] (1) Installation of the workpiece to be measured: The workpiece to be measured is clamped in the clamping mechanism on both sides to ensure that it is stably clamped and can be rotated with the assistance of the rotating clamping pin;

[0016] (2) Setting the auxiliary reference line: Keep the tension wire in a straight line and parallel to the workpiece;

[0017] (3) Measurement: The non-contact measuring mechanism moves along the workpiece to be measured, and the measurement data is transmitted to the background processing platform for processing. The specific processing method is as follows:

[0018] A. A thin laser beam emitted by a laser is projected onto a uniformly rotating polygonal reflector. The intersection of the laser beam and the reflector is located at the focus of the f-θ lens group. The focal length of the f-θ lens group is f0. When the polygonal reflector rotates by θ / 2, the reflected laser beam is deflected by an angle of θ along the axis of the f-θ lens group. After passing through the f-θ lens group, the output beam is parallel to the optical axis and the distance h from the optical axis is h = f·θ.

[0019] B. When the multi-faceted mirror rotates counterclockwise at an angular velocity of ω / 2, the laser beam output from the f-θ lens group rotates at an angular velocity of f· The speed is uniformly swept across the measurement area from the lower edge to the upper edge of the window;

[0020] C. Assume that the initial time is T0. At T0, the laser beam output from the f-θ lens group sweeps across the lower edge of the laser scanner window; at T1, it sweeps across the lower edge of the thin line; during the time t1 from T0 to T1, the laser beam is not blocked and is focused onto the phototube by the receiving lens, causing the phototube to output a high-level signal. At T2, the laser beam output from the lens sweeps across the upper edge of the thin line. During the time t2 from T1 to T2, the laser beam is blocked by the thin line, and the phototube outputs a low-level signal. Similarly, at times T3, T4, and T5, the laser beam output from the lens sweeps across the lower and upper edges of the object being measured and the upper edge of the window, respectively. During the time t3 from T2 to T3, the phototube outputs a high level, during the time t4 from T3 to T4, the phototube outputs a low level, and during the time t5 from T4 to T5, the phototube outputs a high level. Output a level graph, calculate the distance between each edge in the level graph, and the corresponding distance from the axis of the workpiece being measured to the axis of the reference thin line is:

[0021] ; Measuring straightness includes the following steps:

[0022] D. The laser moves smoothly along the axis of the workpiece from the beginning to the end, and records the distance from the reference line to the center of the workpiece at each position. Let the distance from the axis of the workpiece at the beginning to the reference line be h. s , ending with h e , the distance between the head and tail is L, then the distance between the axis of the workpiece and the head is x, and the ideal distance from the center of the workpiece axis to the reference straight line is: ,

[0023] If the measured value at x is hx, then the straightness error at x is: ;

[0024] Take the maximum value of δ(x) between x=0 and x=L, and we get ;

[0025] F. The workpiece rotates and the laser scanner measures the maximum straightness of the long axis:

[0026] Make the workpiece rotate around its axis by an angle α, repeat the above measurement process, and obtain the angle

[0027] δmax(α);

[0028] Take the maximum value of δmax (α) at ​​different angles α, that is, the straightness error of the workpiece is obtained

[0029] .

[0030] In step (2), the auxiliary reference object is replaced by a knife-edge ruler. At time T0, the laser beam output by the lens sweeps across the edge of the knife-edge ruler; at time T1, it sweeps across the lower edge of the object being measured; at time T2, it sweeps across the upper edge of the object being measured; and at time T3, it sweeps across the upper edge of the window. During the time t1 between T0 and T1, the photoelectric tube outputs a high level; during the time t2 between T1 and T2, the photoelectric tube outputs a low level; and during the time t3 between T2 and T3, the photoelectric tube outputs a high level.

[0031] The distance from the axis of the workpiece to the edge of the blade is:

[0032] .

[0033] The beneficial effects of the present invention are:

[0034] The workpiece is firmly fixed and the measurement is accurate. The measurement of each data of the stepped shaft can be achieved by adjusting the relevant components, and the continuity of the measured data is good.

[0035] The design of the pull wire ensures a reasonable reference object, low cost, simple structure, and easy maintenance. The workpiece measurement can be completed by simply controlling the tension of the pull wire to ensure its own straightness, overcoming the error in the measurement result caused by the unevenness of the bracket itself.

[0036] The present invention also involves the evaluation of the measurement error of the equipment. The evaluation results are put into the equipment manual after they are obtained, so that the test personnel can make reasonable reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a perspective view of the structure of the present invention;

[0038] Figure 2 is a three-dimensional diagram from another angle of another embodiment of the present invention;

[0039] Figure 3 It is a front view of the structure of the present invention;

[0040] Figure 4 is a top view of the structure of the present invention;

[0041] Figure 5 It is a left side view of the structure of the present invention;

[0042] Figure 6 It is a right side view of the structure of the present invention;

[0043] Figure 7 It is a rear view of the structure of the present invention;

[0044] Figure 8 It is a schematic diagram of the working principle of the non-contact measurement mechanism of the present invention;

[0045] Figure 9 yes Figure 7 The corresponding measured photoelectric image;

[0046] Figure 10 Schematic diagram of the working principle of a non-contact measurement mechanism in another embodiment of the present invention;

[0047] Figure 11 yes Figure 9 The corresponding measured photoelectric image;

[0048] Component names in the figure: 1. I-shaped slide rail; 2. Head end clamping seat; 3. Tail end clamping seat; 4. Workpiece to be measured; 5. Receiving lens; 6. Non-contact measuring mechanism; 7. Transmitter box; 8. Receiving box; 9. Lens assembly; 10. Photoelectric tube; 11. Blade ruler; 12. Moving motor; 13. Moving belt; 14. Center displacement adjustment handle; 15. Locking handle; 16. Pull wire; 17. Sliding rail; 18. Slider at the bottom of the non-contact measuring mechanism; 19. Drive frame; 20. Transmission belt; 21. Positioning handwheel; 22. Mounting pin; 23. Polyhedral reflector; 24. Motor that drives the polyhedral reflector; 25. Laser; 26. Support device for the moving motor; 27. Bottom support of the non-contact measuring mechanism; 28. Mounting frame. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Example 1

[0050] A laser scanning long axis straight line detection device based on a reference straight line, see Figure 1 , Figures 3 to 6 , workpiece clamping mechanisms are fixedly installed on both sides of the mounting frame, the workpiece clamping mechanisms include a head end clamping seat and a tail end clamping seat, and workpiece mounting pins are coaxially arranged on the mounting surfaces opposite to the head end clamping seat and the tail end clamping seat, and an auxiliary reference object parallel to the main axis is arranged between the workpiece clamping mechanisms; a non-contact measuring mechanism is installed in the direction perpendicular to the main axis of the workpiece to be measured; a driving mechanism for driving the workpiece to rotate along its central axis is also installed on the sliding base, a locking handle is respectively provided on the head end clamping seat and the tail end clamping seat, and a top displacement adjustment handle is provided on the tail end clamping seat.

[0051] The auxiliary reference object comprises a pull line with two ends respectively located on the clamping seats at two ends, and a tension maintaining mechanism is connected to the pull line.

[0052] The tension maintaining mechanism includes a pulling wheel arranged at both ends of the pulling wire. The pulling wheel is installed inside the head end clamping seat and the tail end clamping seat. The pulling wire outlet extends outward. A coil spring is installed on the wheel axle of the pulling wheel to drive the wheel body to reset.

[0053] Auxiliary reference objects include a set of 0-grade blade rulers set just below the workpiece being measured.

[0054] The base includes a straight slide rail, the head end clamping seat is fixed on the straight slide rail, and the tail end clamping seat is slidably installed on the straight slide rail. The driving mechanism includes a clamping pin installed on the head end clamping seat and a driving motor that drives the clamping pin to rotate. A transmission belt is connected between the driving motor and the chuck.

[0055] The non-contact measuring mechanism includes a laser scanner, which includes a transmitting end box and a receiving end box located at both ends of the workpiece to be measured. A rotating multi-faceted reflector, a lens group and a laser transmitter are provided in the transmitting end box. A receiving lens is provided in the receiving end box. A photoelectric tube is provided at the focus of the receiving lens. The lens group includes a group of concave lenses and convex lenses that aggregate scattered light into parallel light.

[0056] A positioning hand wheel for adjusting the position of the clamping needle at the tail end is provided on the tail end clamping seat.

[0057] The base is also provided with a power mechanism for driving the non-contact measuring mechanism to move. The power mechanism includes a moving motor and a moving belt driven by the moving motor. The bottom of the non-contact measuring mechanism is installed on the moving belt.

[0058] A method for measuring a long-axis workpiece, using the measuring device as claimed in claim 1, comprising the following steps:

[0059] (1) Installation of the workpiece to be measured: The workpiece to be measured is clamped in the clamping mechanism on both sides to ensure that it is stably clamped and can be rotated with the assistance of the rotating clamping pin;

[0060] (2) Setting the auxiliary reference line: Keep the tension wire in a straight line and parallel to the workpiece;

[0061] (3) Measurement: The non-contact measuring mechanism moves along the workpiece to be measured, and the measurement data is transmitted to the background processing platform for processing. The specific processing method is as follows:

[0062] A. A thin laser beam emitted by a laser is projected onto a uniformly rotating polygonal reflector. The intersection of the laser beam and the reflector is located at the focus of the f-θ lens group. The focal length of the f-θ lens group is f0. When the polygonal reflector rotates by θ / 2, the reflected laser beam is deflected by an angle of θ along the axis of the f-θ lens group. After passing through the f-θ lens group, the output beam is parallel to the optical axis and the distance h from the optical axis is h = f·θ.

[0063] B. When the multi-faceted mirror rotates counterclockwise at an angular velocity of ω / 2, the laser beam output from the f-θ lens group rotates at an angular velocity of f· The speed is uniformly swept across the measurement area from the lower edge to the upper edge of the window;

[0064] C. Assume that the initial time is T0. At T0, the laser beam output from the f-θ lens group sweeps across the lower edge of the laser scanner window; at T1, it sweeps across the lower edge of the thin line; during the time t1 from T0 to T1, the laser beam is not blocked and is focused onto the phototube by the receiving lens, causing the phototube to output a high-level signal. At T2, the laser beam output from the lens sweeps across the upper edge of the thin line. During the time t2 from T1 to T2, the laser beam is blocked by the thin line, and the phototube outputs a low-level signal. Similarly, at times T3, T4, and T5, the laser beam output from the lens sweeps across the lower and upper edges of the object being measured and the upper edge of the window, respectively. During the time t3 from T2 to T3, the phototube outputs a high level, during the time t4 from T3 to T4, the phototube outputs a low level, and during the time t5 from T4 to T5, the phototube outputs a high level. Output a level graph, calculate the distance between each edge in the level graph, and the corresponding distance from the axis of the workpiece being measured to the axis of the reference thin line is:

[0065] ;

[0066] Measuring straightness includes the following steps:

[0067] D. The laser moves smoothly along the axis of the workpiece from the beginning to the end, and records the distance from the reference line to the center of the workpiece at each position. Let the distance from the axis of the workpiece at the beginning to the reference line be h. s , ending with h e , the distance between the head and tail is L, then the distance between the axis of the workpiece and the head is x, and the ideal distance from the center of the workpiece axis to the reference straight line is:

[0068] ,

[0069] If the measured value at x is hx, then the straightness error at x is:

[0070] ;

[0071] Take the maximum value of δ(x) between x=0 and x=L, and we get ;

[0072] F. The workpiece rotates and the laser scanner measures the maximum straightness of the long axis:

[0073] Make the workpiece rotate around its axis by an angle α, repeat the above measurement process, and obtain the angle

[0074] δmax(α);

[0075] Take the maximum value of δmax (α) at ​​different angles α, that is, the straightness error of the workpiece is obtained

[0076] .

[0077] In this embodiment, during the debugging phase of the device, an error detection step is also included:

[0078] Assume that the repeatability error of the laser scanning measuring instrument is δr, the parallelism error of the sliding platform caused by the linear guide is δp, the roundness error of the tensioned fine straight line is δrt, the error caused by the vibration of the tensioned fine straight line is δv, and the total measurement error of the entire measuring device is δt.

[0079] The following uses the 10m long axis straight line detection as an example to estimate the error of various detection methods in measuring its straightness

[0080] For a measuring device without a reference line, the straightness measurement error is mainly determined by the repeatability error δr of the laser scanning measuring instrument and the parallelism error δp of the sliding platform.

[0081] δt≈δr+δp;

[0082] The repeatability error δr of the laser scanning measuring instrument can reach 2μm.

[0083] The parallelism error δp of the sliding platform: If three ultra-precision linear guide rails with a length of 3.5m from a well-known brand are used, the total error is 42μm;

[0084] Then δt≈2μm+42μm=44μm;

[0085] For the measuring device based on the tensioned thin line, the straightness measurement error is mainly determined by the repeatability error δr of the laser scanning measuring instrument, the roundness error δrt of the tensioned thin line, and the error δv caused by the vibration of the tensioned thin line, and has nothing to do with the parallelism error δp of the sliding platform.

[0086] δt≈δr+δrt+δv;

[0087] The roundness error δrt of the tensioned thin straight line: Taking the piano wire with a diameter of 0.5mm as an example, its roundness error is ≤4μm.

[0088] The error δv caused by the vibration of the tensioned thin line: According to the test, the tensioned thin line with a length of 10m is 7μm under the general vibration isolation condition.

[0089] Then δt≈2μm+4μm+7μm=13μm

[0090] The measuring device based on the tensioned thin straight line has higher measurement accuracy when the vibration of the installation base is small. Example 2

[0091] The principle of this embodiment is the same as that of embodiment 1, with the specific difference being that the auxiliary reference object in step (2) is replaced by a knife-edge ruler. Accordingly, at time T0, the laser beam output by the lens sweeps across the edge of the knife-edge ruler; at time T1, it sweeps across the lower edge of the object being measured; at time T2, it sweeps across the upper edge of the object being measured; and at time T3, it sweeps across the upper edge of the window. During the time t1 from T0 to T1, the photoelectric tube outputs a high level; during the time t2 from T1 to T2, the photoelectric tube outputs a low level; and during the time t3 from T2 to T3, the photoelectric tube outputs a high level.

[0092] The distance from the axis of the workpiece to the edge of the blade is:

[0093] .

[0094] In this embodiment, the corresponding error detection steps are as follows:

[0095] For the measuring device based on the knife edge ruler, the straightness error of the blade of the knife edge ruler group is δks, and the straightness error of a single knife edge ruler in the knife edge ruler group is δk. The straightness measurement error is mainly determined by the repeatability error δr of the laser scanning measuring instrument and the straightness error δks of the blade of the knife edge ruler group.

[0096] When installing the blade assembly, to ensure the straightness of each blade edge, a tensioned thin line is placed above the blade edge as a reference datum. This reference datum is used to calibrate the overall straightness of the blade assembly. This is done by using a laser scanning measuring instrument to measure the distance from the tensioned thin line to the blades at both ends of each blade (taking the average of multiple measurements at each end to eliminate the influence of the thin line vibration). Each blade is then adjusted so that the distance from each blade edge to the reference line is equal. The straightness error δks of the blade assembly is then:

[0097] δks=δk+δr+δrt;

[0098] Among them, δk is the straightness error of a single blade, δr is the repeatability error of the laser scanning measuring instrument, and δrt is the roundness error of the tensioned thin straight line.

[0099] When a straightness-calibrated blade set is used as a straight line reference, the error in measuring the straightness of the workpiece is:

[0100] δt≈δks+δr=δk+2δr+δrt;

[0101] For a 10m long workpiece, three 3.5m long blade rulers are required. The straightness error of a well-known brand of grade 0 blade ruler of this specification is δk=16μm. Taking δr=2μm and δrt=4μm, the total measurement error is:

[0102] δt≈16μm+2×2μm+4μm=24μm;

[0103] The measuring device based on the knife edge is less affected by the vibration of the installation base and can perform fast measurements.

[0104] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A laser scanning long-axis straight line detection device based on a reference straight line, characterized by: The invention comprises a sliding base slidably mounted on a mounting frame, a workpiece clamping mechanism fixedly mounted on both sides of the sliding base, the workpiece clamping mechanism comprising a head end clamping seat and a tail end clamping seat, workpiece mounting ejectors are coaxially arranged on the mounting surfaces opposite to the head end clamping seat and the tail end clamping seat, and an auxiliary reference object parallel to the main axis is arranged between the workpiece clamping mechanisms; a non-contact measuring mechanism is installed in a direction perpendicular to the main axis of the workpiece to be measured; a driving mechanism that drives the workpiece to be measured to rotate along its central axis is also installed on the sliding base, a locking handle is respectively provided on the head end clamping seat and the tail end clamping seat, and a top displacement adjustment handle is provided on the tail end clamping seat; The measurement method of the laser scanning long axis linear detection device includes the following steps: A. A thin laser beam emitted by a laser is projected onto a uniformly rotating polygonal reflector. The intersection of the laser beam and the reflector is located at the focus of the f-θ lens group. The focal length of the f-θ lens group is f0. When the polygonal reflector rotates by θ / 2, the reflected laser beam is deflected by an angle of θ along the axis of the f-θ lens group. After passing through the f-θ lens group, the output beam is parallel to the optical axis and the distance h from the optical axis is h = f·θ. B. When the multi-faceted mirror rotates counterclockwise at an angular velocity of ω / 2, the laser beam output from the f-θ lens group rotates at an angular velocity of f· The speed is uniformly swept across the measurement area from the lower edge to the upper edge of the window; C. Assume that the initial time is T0. At T0, the laser beam output from the f-θ lens group sweeps across the lower edge of the laser scanner window; at T1, it sweeps across the lower edge of the thin line; during the time t1 from T0 to T1, the laser beam is not blocked and is focused onto the phototube by the receiving lens, causing the phototube to output a high-level signal. At T2, the laser beam output from the lens sweeps across the upper edge of the thin line. During the time t2 from T1 to T2, the laser beam is blocked by the thin line, and the phototube outputs a low-level signal. Similarly, at times T3, T4, and T5, the laser beam output from the lens sweeps across the lower and upper edges of the object being measured and the upper edge of the window, respectively. During the time t3 from T2 to T3, the phototube outputs a high level, during the time t4 from T3 to T4, the phototube outputs a low level, and during the time t5 from T4 to T5, the phototube outputs a high level. Output a level graph, calculate the distance between each edge in the level graph, and the corresponding distance from the axis of the workpiece being measured to the axis of the reference thin line is: ； D. The distance from the reference straight line to the center of the workpiece at each position, and the distance from the axis of the workpiece at the head end to the reference straight line is h s , ending with h e , the distance between the head and tail is L, then the distance between the axis of the workpiece and the head is x, and the ideal distance from the center of the workpiece axis to the reference straight line is: , If the measured value at x is h x , then the straightness error at x is: ; Take the maximum value of δ(x) between x=0 and x=L, and we get .

2. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: The auxiliary reference object includes a pull line with two ends respectively located on the clamping seats at the two ends, and a tension maintaining mechanism is connected to the pull line.

3. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 2, characterized in that: The tension maintaining mechanism includes a wire pulling wheel arranged at both ends of the wire pulling wheel, the wire pulling wheel is installed inside the head end clamping seat and the tail end clamping seat, the wire pulling outlet extends outward, and a coil spring is installed on the wheel axle of the wire pulling wheel to drive the wheel body to reset.

4. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: The auxiliary reference objects include a set of 0-level blade rulers arranged directly below the workpiece to be measured, and the blades of the blade rulers are adjusted to form a straight line and parallel to the axis of the workpiece to be measured.

5. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: The sliding base includes a straight line slide rail, the head end clamping seat is fixed on the straight line slide rail, the tail end clamping seat is slidably installed on the straight line slide rail, the driving mechanism includes a clamping pin installed on the head end clamping seat and a driving motor that drives the clamping pin to rotate, and a transmission belt is connected between the driving motor and the head end clamping seat.

6. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: The non-contact measurement mechanism includes a laser scanner, which includes a transmitting end box and a receiving end box located at both ends of the workpiece to be measured. A rotating polygonal reflector, a lens group and a laser transmitter are provided in the transmitting end box. A receiving lens is provided in the receiving end box. A photoelectric tube is provided at the focus of the receiving lens. The lens group includes a group of concave lenses and convex lenses that aggregate scattered light into parallel light.

7. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 3, characterized in that: The tail end clamping seat is provided with a positioning hand wheel for adjusting the position of the clamping needle at the tail end.

8. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: The base is also provided with a power mechanism for driving the non-contact measuring mechanism to move. The power mechanism includes a moving motor and a moving belt driven by the moving motor. The bottom of the non-contact measuring mechanism is installed on the moving belt via a slider.

9. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: After step D, the following steps are also included: E. The workpiece rotates and the laser scanner measures the maximum straightness of the long axis: Make the workpiece rotate around its axis by an angle α, repeat the above measurement process, and obtain the angle δmax (α); Take the maximum value of δmax (α) at ​​different angles α, that is, the straightness error of the workpiece 。 10. The laser scanning long-axis straight line detection device based on a reference straight line according to claim 1, characterized in that: In step (2), the auxiliary reference objects are replaced by a set of blade rulers, and the blades of each blade ruler are adjusted to a straight line. Correspondingly, at time T0, the laser beam output by the lens sweeps across the edge of the blade ruler; at time T1, it sweeps across the lower edge of the object to be measured; at time T2, it sweeps across the upper edge of the object to be measured; at time T3, it sweeps across the upper edge of the window; during the time t1 from T0 to T1, the photoelectric tube outputs a high level; during the time t2 from T1 to T2, the photoelectric tube outputs a low level; during the time t3 from T2 to T3, the photoelectric tube outputs a high level; The distance from the axis of the workpiece to the edge of the blade is: 。

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