CN115493545A - Measuring device and method for straightness error of guide rail mounting surface - Google Patents

Abstract

A device and method for measuring the straightness error of a guide rail mounting surface; the device includes a support base, a slide rail is connected to the support base, a sliding body is arranged on the slide rail, a reflector is arranged on the upper part of the sliding body, and a For the photoelectric sensor opposite to the reflector, the lower part of the sliding body is provided with a connector, and the first displacement sensor for measuring the straightness of the vertical mounting surface of the guide rail and the second displacement sensor for measuring the straightness of the horizontal mounting surface of the guide rail are installed on the connector. The displacement sensor adopts an eddy current sensor; the device is combined with a photoelectric autocollimator for measurement. The first displacement sensor and the second displacement sensor are used to measure the horizontal installation surface and the vertical installation surface of the tested guide rail respectively, and the photoelectric sensor is responsible for transmitting the position of the measurement point. For position information, the photoelectric autocollimator measures the inclination angle of the line connecting two adjacent points of the measured straight line relative to the main optical axis. The invention can measure the straightness of the bottom surface and the side surface of the guide rail installation surface of the machine tool at one time, has low measurement cost, and has high measurement efficiency and precision.

Description

Measuring device and method for straightness error of guide rail mounting surface

technical field

The invention relates to a fast measuring device and a measuring method for the straightness of a mounting surface of a guide rail used on mechanical equipment (such as a machine tool, an engraving machine, a cutting machine, etc.), and belongs to the technical field of processing and detection of a cutting machine guide rail.

Background technique

The straightness error of the guide rail mounting surface will directly affect the final performance of the mechanical equipment, and it is necessary to accurately and quickly measure the error. In actual production, due to the special position of the guide rail installation plane and the narrow measurement surface, the existing detection tools cannot meet the fast and accurate measurement requirements. Therefore, it is necessary to develop a new detection device.

Machine tool guide rail errors are mainly manifested in the following aspects: straightness error in the horizontal plane after the guide rail is assembled, straightness error in the vertical plane and parallelism error in the vertical plane after the front and rear guide rails are installed. These errors are reflected on the installation plane of the mechanical equipment guide rail as: the straightness error of the two guide rail installation surfaces in the horizontal plane and the vertical plane, and the parallelism error on both sides of the front and rear guide rail installation planes.

Straightness error is a shape tolerance that limits the variation of the actual straight line to the ideal straight line. At present, tools such as level gauges, autocollimators, and laser interferometers are used in the measurement of straightness of machine tool guide rail mounting surfaces.

Patent document CN108972156A relates to a method for measuring the straightness error of machine tool guide rails. The laser interference principle is used to measure the straightness of guide rails. The measurement system used includes laser light source and collimation system, reflective prism, objective lens, image sensor and image processing equipment , the reflective prism is a four-sided conical right-angled isosceles reflective prism, which is an external reflector of the measurement system, two groups of opposite sides are perpendicular to each other, the four sides are isosceles triangles, the bottom surface is a square, and the section is an isosceles right triangle , fixed on the machine tool spindle. The measurement method is as follows: a collimated laser beam is emitted by a laser light source and a collimation system, reflected by a four-sided conical right-angle isosceles reflective prism, and then collimated and converged by the objective lens to be imaged on the image sensor; when the four-sided conical right-angle isosceles reflective prism is randomly When the bed spindle moves in a straight line, the position of the light spot formed by the reflected light on the image sensor will change. After the image processing equipment analysis and subsequent calculation, the straightness error of the machine tool guide rail can be obtained.

CN101315276A discloses a device for measuring the straightness error of the guide rail of a CNC machine tool. A laser head is installed on the fixed guide rail, and a reflector for measuring linear deflection is installed at the corresponding end of the moving guide rail. The measurement direction is the same as the direction of the straightness error to be controlled. A vertical guide rail is installed on the moving guide rail. The moving direction of the vertical moving guide rail is consistent with the deflection direction of the moving guide rail. The workpiece is installed on the vertical moving guide rail. The laser head on the laser head measures the value of the deflection and controls the vertical moving guide rail to produce a movement with equal distance and opposite direction through the numerical control system to offset the deflection caused by the straightness error of the guide rail, thereby correcting the straightness error of the moving guide rail.

The method for measuring the straightness error of the guide rail based on the principle of laser interference has good stability and high measurement accuracy, but the operation is complicated and the cost is too high.

CN206618381U discloses a machine tool guide rail straightness measuring device, including a base, a measuring table, an inductive measuring head, a sending device and a roller; the measuring table is arranged on the base; the inductive measuring head is connected with the measuring table through a support; the sending device is installed on the support above; the roller is installed on the side plate of the base; the circumference of the roller is equal to the length of the contact surface between the base and the ground; a first sensor is installed on one side of the roller, and a second sensor is installed on the side plate. When the first sensor follows the roller and rotates to the minimum distance from the second sensor, the electrical probe reads the test data and transmits it to the sending device through the connection line. The disadvantages of the above-mentioned measuring device are: firstly, the operation steps are relatively cumbersome, and secondly, the errors are not separated and processed, resulting in insufficient accuracy.

Contents of the invention

In order to overcome the defects existing in the prior art of guide rail straightness error measurement, the object of the present invention is to provide a fast measuring device and method for measuring the straightness of guide rail installation surface with high measurement efficiency and precision.

The rapid measurement device for the straightness of the guide rail mounting surface of the present invention is realized by the following technical solutions:

The measuring device includes a support seat, a slide rail is connected to the support seat, a sliding body is arranged on the slide rail to move horizontally and linearly along the slide rail, a reflector is arranged on the upper part of the slide body, and a The photoelectric sensor (reflector type), the lower part of the sliding body is provided with a connector, and the first displacement sensor for measuring the straightness of the vertical mounting surface of the guide rail and the second displacement sensor for measuring the straightness of the horizontal mounting surface of the guide rail are installed on the connector. The displacement sensor adopts the eddy current sensor.

The connecting head includes a bracket, one end of the bracket is connected to the sliding body (detachable connection), and the other end is symmetrically connected to two slide tables (detachable), and the slide table is connected with a first fixed frame via a slider. A second fixing piece is connected to the bracket; the first fixing piece is used to install the first displacement sensor arranged in the vertical direction (for measuring the straightness of the vertical installation surface of the guide rail), and the second fixing piece is used to install the first displacement sensor arranged toward the bottom surface The second displacement sensor (used to measure the straightness of the horizontal mounting surface of the guide rail). The two fixing parts and the bracket move on the slide rail following the sliding body.

Two sets of adjustment devices are provided on the slide table (respectively adjust the first fixed part and the first displacement sensor on it and the second fixed part and the second displacement sensor on it), the first adjustment device and the second adjustment device The structure is the same, including the horizontal micro-adjustment mechanism and the micro-feed adjustment mechanism installed on the mounting plate, and the mounting plate is installed on the slide table. The horizontal fine-tuning mechanism includes a rotating shaft, which is installed on the mounting plate, and the rotating shaft is connected with the first fixing piece, and the outer end of the rotating shaft is fixedly equipped with a horizontal fine-tuning knob (when the horizontal fine-tuning knob is turned, the rotating shaft and the The first fixing member rotates accordingly to realize the angle rotation of the first fixing member in the plane). The micro-feed adjustment mechanism includes a lead screw (ball screw) which is installed on the mounting plate, the lead screw is connected with the first fixing part through a nut (ball body), and the outer end of the lead screw is fixedly installed with a feed Feed the fine-tuning knob (feed the fine-tuning knob to drive the lead screw to rotate, and the lead screw transmits power to the nut (ball body), which converts the rotation into a linear motion of the nut (ball body), and the nut then drives the first fixing part to move) . The horizontal micro-adjustment mechanism also includes a horizontal dial, the horizontal dial is fixed on the mounting plate, and a horizontal pointer fixed on the rotating shaft is arranged on the outside of the horizontal dial. The micro-feed adjustment mechanism also includes a feed scale ring, which is fixed on the mounting plate, and a feed pointer fixedly installed on the lead screw is arranged outside the feed scale ring.

The horizontal micro-adjustment mechanism of the first adjusting device realizes the angle rotation of the first fixing member in the plane by rotating the rotating shaft to make the first fixing member rotate accordingly, and keeps the distance between the surface to be measured of the guide rail and the first fixing member. The micro-feed adjustment mechanism of the first adjustment device adjusts the distance between the first displacement sensor and the vertical mounting surface of the tested guide rail by 0.4-0.6mm by rotating the screw to drive the second fixing member to move. The horizontal micro-adjustment knob of the second adjustment device maintains a horizontal relationship between the surface to be measured of the guide rail and the second fixing member, and the micro-feed adjustment mechanism of the second adjustment device adjusts the distance between the second displacement sensor and the measured position through the feed screw. The horizontal mounting surface of the guide rail is 0.5-08mm.

The second displacement sensor is screwed to the second fixing member, and the first displacement sensor is connected to the second fixing member by bonding.

Bearings are installed on the bottom surface and the side wall of the sliding body, and the bottom surface and the inner surface of the side wall adopt a grid structure design to reduce the sliding friction between the sliding body and the sliding rail contact surface during the measurement process.

Based on the measurement method of the above-mentioned guide rail straightness fast measuring device, the measurement is carried out in conjunction with the photoelectric autocollimator. Measuring component), place the bridge plate on one end of the measured guide rail to start measurement, drag the bridge plate end to end along the equal span of the guide rail, record the inclination angle of the line connecting two adjacent points of the measured straight line with respect to the main optical axis, Read out the measured values Δz and Δx of the photoelectric autocollimator;

Specifically include the following steps:

(1) Adjust the body of the equipment to be tested to the level, and move the sliding body so that it moves from the initial position of the mounting surface of the tested guide rail to the final position at a uniform speed;

(2) Two sets of displacement sensors (the first displacement sensor and the second displacement sensor) are used to combine with the photoelectric sensor and cooperate with the photoelectric autocollimator to measure the error generated by the reference plane to the straightness measurement. During the process of moving the initial position of the guide rail installation surface to the final position, the position information of the point to be measured on the side is collected, and the first displacement sensor arranged in the vertical direction (for measuring the straightness of the vertical installation surface of the guide rail)) measurement data Δz' includes the measured The vertical straightness error Δz of the guide rail installation surface and the error Δz” generated by the reference plane to the vertical straightness measurement, the measurement data Δx’ of the second displacement sensor (used to measure the straightness of the horizontal installation surface of the guide rail) arranged towards the bottom surface includes Measure the horizontal straightness error Δx of the mounting surface of the guide rail and the error Δx” produced by the reference plane to the horizontal straightness measurement. At this time, the data measured by the photoelectric collimator are considered to be the guide rail straightness errors Δz and Δx; therefore, the readings of the photoelectric collimator Δz" and Δx" are calculated by subtracting Δz and Δx from the measured data of the displacement sensor Δz' and Δx'; that is:

(3) Measure Δz″ _i and Δx″ _i at each position in the entire movement stroke, i=1, 2, 3....n, and then based on the least square principle, the reference plane is calculated by curve fitting method Δz″ _i and Δx″ _i of each point corresponding to above are fitted, and the fitting formula is as follows:

m为计算得到的基准平面上对应的直线度误差谐波的最高阶数，由采样定理可知，当标定点个数n为偶数时，最多只能计算到

阶系数；当n为奇数时，最多只能计算到m＝(n-1)/2阶系数，根据实际情况调整拟合阶数，当阶次降低时，拟合曲线与线性插补法对比标准差不再减少时，就不再降低模型的阶数；A_k,B_k为第k阶误差谐波系数，C_k和

为第k阶误差谐波的幅值和相位；g(y) and h(y) are the straightness errors in the vertical direction and horizontal direction of the reference plane at the position y of the guide rail movement, respectively, where

m is the highest order number of the corresponding straightness error harmonic on the calculated reference plane. According to the sampling theorem, when the number of calibration points n is an even number, it can only be calculated up to

Order coefficient; when n is an odd number, only m=(n-1)/2 order coefficient can be calculated at most, and the fitting order is adjusted according to the actual situation. When the order is reduced, the fitting curve is compared with the linear interpolation method When the standard deviation no longer decreases, the order of the model will no longer be reduced; A _k , B _k are the kth order error harmonic coefficients, C _k and

is the magnitude and phase of the kth order error harmonic;

由公式：(4) Solving C _k and

By the formula:

because

得：Depend on

have to:

Using coordinate transformation, establish the following equation:

make:

X=[A ₁ ,A ₂ ,...,A _m ,B ₁ ,B ₂ ,...,B _m ] ^T ,

Convert it to matrix form:

Calculated by the method of least squares:

In this way, the kth order error harmonic coefficients A _k and B _k can be obtained, and then the amplitude C _k and phase can be obtained

(5) Finally, through the error compensation formula:

And the errors g(y _j ) and h(y _j ) generated by any point j (j=1,2,3...) on the reference plane in the entire displacement range to the straightness measurement are obtained through the above fitting curve, and Straightness error at any point of the guide rail;

(6) Draw the measurement point position information measured by the photoelectric sensor and the error values g(y _j ) and h(y _j ) obtained in step (5) into the straightness deviation curves of the side and bottom surfaces, and then use the minimum containment The area method is used to obtain the final straightness error of the mounting surface to be tested.

Compared with the prior art, the present invention has simple structure and convenient measurement, improves measurement efficiency and measurement accuracy on the one hand, reduces cost on the other hand, and has the following beneficial technical effects:

1. The support seat in the device of the present invention is responsible for the positioning and fixing of the whole device, and the displacement sensor used to measure the straightness of the bottom surface of the installation surface is moved through the sliding body, which effectively reduces the sliding friction between the sliding body and the contact surface of the slide rail during the measurement process , the straightness error of the slide rail itself is controlled within a small range, and the combination of the reflector and the photoelectric sensor is responsible for transmitting the position information of the measuring point.

2. The device of the present invention uses multiple sets of displacement sensors for measurement, which is a non-contact continuous measurement method. The eddy current sensor has the characteristics of firmness, low cost, non-contact, high performance and insensitivity to environmental pollutants, and is suitable for use in The online displacement measurement can measure the straightness of the bottom surface and the side surface of the guide rail installation surface of the machine tool at one time, which improves the measurement efficiency; in addition, the operation is simple, the repeatability, operability and stability are good.

3. The displacement sensor group is installed on the connector. The two sets of displacement sensors are respectively responsible for the shape error of the vertical installation surface and the horizontal installation surface of the guide rail. The measurement efficiency and accuracy can reach a high level. The structure design is reasonable and the installation is convenient. It needs to be disassembled and easy to use.

4. In the measuring method of the present invention, by setting two sets of displacement sensors on the side and the bottom of the installation surface respectively, the errors are measured separately, so that the measurement accuracy can be greatly improved.

Description of drawings

Fig. 1 is the overall structure diagram of the rapid measuring device for the straightness of the mounting surface of the guide rail according to the present invention.

Fig. 2 is a structural schematic diagram of the connector in the measuring device of the present invention.

Fig. 3 is a schematic diagram of the measurement process of the present invention.

Fig. 4 is a schematic perspective view of the three-dimensional structure of the adjusting device in the present invention.

Fig. 5 is a schematic top view of the adjusting device in the present invention.

In the figure: 1. Body, 2. Connecting head, 3. Sliding body, 4. Support seat, 5. Reflecting plate, 6. Slide rail, 7. Photoelectric sensor, 8. Adjusting device, 9. Second fixing part, 10. Second displacement sensor, 11. Slider, 12. Bracket, 13. First fixed member, 14. First displacement sensor, 15. Mirror, 16. Bridge plate, 17. Photoelectric autocollimator, 18. Mounting plate, 19. Horizontal fine-tuning knob, 20. Rotary shaft, 21. Adjusting head, 22. Horizontal dial, 23. Horizontal pointer, 24. Ball screw, 25. Nut, 26. Feed scale ring, 27. Advance Feed the fine-tuning knob, 28. Feed the pointer.

detailed description

Referring to Fig. 1, the fast measuring device of the straightness of the guide rail mounting surface of the present invention comprises support bases 4 symmetrically arranged at both ends of the fuselage 1, and a slide rail 6 is fixed on the support base 4, and the slide rail 6 is provided with a The sliding body 3 (sliding trolley) that rail 6 moves, and the top of sliding body 3 is provided with reflecting plate 5, and one end on the slide rail 6 is provided with the photoelectric sensor 7 that can cooperate with reflecting plate 5 to measure the position information of the measuring point on the mounting surface. A connecting head 2 is provided on the side of the sliding body 3, and the connecting head 2 is used for installing two displacement sensors for measuring the horizontal straightness and vertical straightness of the mounting surface. A first displacement sensor 8 and a second displacement sensor 10 are installed on the connector 2, the first displacement sensor 8 is used to measure the straightness of the vertical installation surface of the guide rail, and the second displacement sensor 10 is used to measure the straightness of the horizontal installation surface of the guide rail. The two displacement sensors adopt eddy current sensors.

The structure of the connecting head 2 is shown in FIG. 2 , including a bracket 12 , a slide table 11 , a first fixing piece 13 and a second fixing piece 9 . Wherein, one end of the bracket 12 is detachably connected to the sliding body 3, and two detachable sliding tables 11 are connected symmetrically on both sides of the other end, and the first fixing member 13 and the second fixing member 13 are respectively connected to the two sliding tables 11 by rails. Part 9, the first fixed part 13 and the second fixed part 9 can move horizontally along the respective sliding tables 11, and the first displacement sensor 14 facing the side for measuring the straightness of the side of the installation surface is provided on the first fixed part 13 . A second displacement sensor 10 for measuring the straightness of the bottom surface of the installation surface is provided on the second fixing member 9 toward the bottom surface. The connection form between the first displacement sensor 8 and the second fixing member 9 is adhesive. The second displacement sensor 10 is screwed to the second fixing member 9 .

In order to reduce the sliding friction between the sliding body and the sliding rail contact surface during the measurement process, precision rolling bearings are installed on the bottom surface and the side wall of the sliding body 3, and the bottom surface and the inner surface of the side wall adopt a grid structure design.

The end of the slide table 11 is provided with two sets of adjustment devices 8, the two sets of adjustment devices have the same structure, as shown in Figure 4 and Figure 5, including a horizontal micro-adjustment mechanism and a micro-feed adjustment mechanism installed on the mounting plate 18, The mounting plate 18 is mounted on the slide table 11 . The horizontal micro-adjustment mechanism includes a rotating shaft 20 and a horizontal dial 22. The rotating shaft 20 is installed on the mounting plate 18, and the inner end of the rotating shaft 20 is connected with an adjusting head 21 (mainly playing a matching connection to improve the precision of the micro-adjustment) , the adjusting head 21 is connected with the first fixing member 13 again, the horizontal dial 22 is inserted into the outer end of the rotating shaft 20 and fixed on the mounting plate 18, and the outer side of the horizontal dial 22 is provided with a fixed mounting on the rotating shaft 20 Horizontal pointer 23, the horizontal pointer 23 is positioned by a positioning piece (jack screw) to avoid false touch, and the outer end of the rotating shaft 20 is fixedly equipped with a horizontal fine-tuning knob 19. By turning the horizontal fine-tuning knob 19 to make the rotating shaft 20 and the first fixing member 13 rotate together, the rotation of the first fixing member 13 in the plane angle is realized, and the horizontal state between the surface to be measured of the guide rail and the first fixing member 13 is achieved. The rotation angle is observed by the indicated position of the horizontal pointer 23 on the horizontal scale 22 .

Micro-feed adjustment mechanism comprises ball screw 24 and feed scale ring 26, and ball screw 24 is installed on the mounting plate 18, and the inner end of ball screw 24 is equipped with nut 25 (ball body), and nut 25 is connected with first again. The fixing parts 13 are connected, and the feed scale ring 26 is inserted into and fixed on the mounting plate 18 by the outer end of the ball screw 24, and the feed pointer 28 fixedly installed on the ball screw 24 is arranged on the outside of the feed scale ring 26 , the feed pointer 28 is positioned by a positioning member (jack screw) to avoid false touches, and the outer end of the ball screw 24 is fixedly equipped with a feed fine-tuning knob 27 . Turn the feed fine-tuning knob 27 to rotate the ball screw 24, the ball screw 24 transmits the power to the nut 25 (ball body), and converts the rotation into the linear motion of the nut 25, and the nut 25 drives the first fixing member 13 to feed and move , the feed rate is observed by the indicated position of the feed pointer 28 on the feed scale ring 26 .

By turning the horizontal fine-tuning knob 19 of the first adjusting device, the first fixing member 13 can be rotated together, maintaining the horizontal relationship between the surface to be measured of the guide rail and the first fixing member 13, and fine-tuning through the feed of the first adjusting device The knob 27 can adjust the first displacement sensor 14 to be 0.4-0.6mm away from the vertical mounting surface of the tested guide rail.

Through the horizontal fine-tuning knob of the second adjustment device, the second fixing member 9 can be rotated together, and the horizontal relationship between the surface to be measured of the guide rail and the second fixing member 9 can be maintained, and can be adjusted through the horizontal fine-tuning knob of the second adjusting button The second displacement sensor 10 is 0.5-08 mm away from the horizontal mounting surface of the tested guide rail.

During use, the fuselage 1 needs to be leveled before measurement. The sliding rail 6 is sleeved in the sliding body 3, placed on the support base 4, and fixed by screw connection. The connecting head 2 is connected to one end of the sliding body 3, wherein the first displacement sensor 14 faces the vertical installation surface of the tested guide rail of the bed, and the second displacement sensor 10 faces the horizontal installation surface of the measured guide rail of the machine body. After measuring one side of the guide rail, you can change the connector 2 and the sensor to the other side for re-measurement (see Figure 1).

The above-mentioned device is combined with the photoelectric autocollimator 17 to measure the straightness of the guide rail quickly. Measuring component, place the bridge plate 16 on one end of the measured guide rail to start measurement, drag the bridge plate 16 end to end along the guide rail with an equal span, and record the inclination angle of the line connecting two adjacent points of the measured straight line with respect to the main optical axis , read out the measured values Δz and Δx of the photoelectric autocollimator.

Specifically, the following measurement steps are included.

1. Adjust the body 1 to the level, and move the sliding body 3 so that it moves from the initial position of the installation surface to be tested to the final position at a uniform speed;

2. Combine the reflective plate type photoelectric sensor 7 with two eddy current displacement sensors (the first displacement sensor 14 and the second displacement sensor 10) and cooperate with the photoelectric collimator 17 to measure the error generated by the reference plane to the straightness measurement, the photoelectric The sensor 7 collects the position information of the point to be measured on the side during the movement of the sliding body 3 from the initial position of the installation surface to be measured to the end position, and the measurement data Δz′ of the first displacement sensor 14 includes the straightness error Δz in the vertical direction of the measured guide rail and The error Δz” produced by the reference plane to the vertical straightness measurement, the measurement data Δx’ of the second displacement sensor 10 includes the horizontal straightness error Δx of the measured guide rail and the error Δx” produced by the reference plane to the horizontal straightness measurement. The data measured by the collimator 17 can be regarded as guide rail straightness errors Δz and Δx. Therefore, Δz" and Δx" can be calculated by subtracting the readings Δz and Δx of the photoelectric collimator 17 from the measurement data Δz' and Δx' of the eddy current displacement sensor, namely:

3. Measure Δz _i ” and Δx _i ” (i=1,2,3....n) at positions in the entire movement stroke, and then based on the principle of least squares, use the method of curve fitting to fit the reference plane Δz″ _i and Δx″ _i of each point corresponding to above are fitted, and the fitting formula is as follows:

m为可以计算得到的基准平面上对应的直线度误差谐波的最高阶数，由采样定理可知，当标定点个数n为偶数时，最多只能计算到

阶系数；当n为奇数时，最多只能计算到m＝(n-1)/2阶系数，一般会根据实际情况调整拟合阶数，当阶次降低时，拟合曲线与线性插补法对比标准差不再减少时，工程上就不再降低模型的阶数。A_k,B_k为第k阶误差谐波系数，C_k和

为第k阶误差谐波的幅值和相位。g(y) and h(y) are the straightness errors in the vertical direction and horizontal direction of the reference plane at the position y of the guide rail movement, respectively. in

m is the highest order number of the straightness error harmonic corresponding to the reference plane that can be calculated. According to the sampling theorem, when the number of calibration points n is an even number, it can only be calculated up to

Order coefficient; when n is an odd number, only m=(n-1)/2 order coefficient can be calculated at most, and the fitting order will generally be adjusted according to the actual situation. When the order is reduced, the fitting curve and linear interpolation When the standard deviation of the method comparison is no longer reduced, the order of the model will no longer be reduced in engineering. A _k , B _k is the kth order error harmonic coefficient, C _k and

is the magnitude and phase of the kth order error harmonic.

由公式4. Solve for C _k and

by the formula

because

得：Depend on

have to:

Using the idea of coordinate transformation, the following equation is established:

make:

X＝[A ₁ ,A ₂ ,...,A _m ,B ₁ ,B ₂ ,...,B _m ] ^T

Convert it to matrix form:

It can be obtained by using the least squares method:

In this way, the kth order error harmonic coefficients A _k and B _k can be obtained, and then the amplitude C _k and phase can be obtained

5. Finally, through the error compensation formula:

And the errors g(y _i ) and h(y _i ) produced by any point j (j=1,2,3...) on the reference plane in the entire displacement range to the straightness measurement are obtained through the above fitting curve, then The straightness error of any point on the guide rail can be obtained.

6. Draw the measurement point position information measured by the photoelectric sensor 7 and the error values g(y _i ) and h(y _i ) obtained in step 5 into the straightness deviation curves of the side and bottom surfaces, and then use the minimum containment area method , to obtain the final straightness error of the mounting surface to be tested.

Claims (8)

1. A quick measuring device of guide rail installation face straightness accuracy, characterized by: the device comprises a supporting seat, a sliding rail is connected to the supporting seat, a sliding body which can move along the sliding rail in a horizontal linear mode is arranged on the sliding rail, a reflecting plate is arranged on the upper portion of the sliding body, a photoelectric sensor which is opposite to the reflecting plate is mounted on the sliding rail, a connector is arranged on the lower portion of the sliding body, and a first displacement sensor used for measuring the straightness of a vertical mounting surface of the guide rail and a second displacement sensor used for measuring the straightness of a horizontal mounting surface of the guide rail are mounted on the connector.

2. The device for rapidly measuring the straightness of the guide rail installation surface according to claim 1, wherein: the connector comprises a support, one end of the support is connected to the sliding body, two sliding tables are symmetrically connected to two sides of the other end of the support, a first fixing piece is connected to each sliding table through a sliding block, and a second fixing piece is connected to the support; the first fixing member is used for mounting the first displacement sensor arranged in the vertical direction, and the second fixing member is used for mounting the second displacement sensor arranged towards the bottom surface.

3. The device for rapidly measuring the straightness of a guide rail installation surface according to claim 2, wherein: two groups of adjusting devices are arranged on the sliding table, the first adjusting device and the second adjusting device have the same structure and comprise a horizontal micro-adjusting mechanism and a micro-feeding adjusting mechanism which are arranged on an installation plate, and the installation plate is arranged on the sliding table; the horizontal fine adjustment mechanism comprises a rotating shaft, the rotating shaft is arranged on the mounting plate and connected with the first fixing piece, and a horizontal fine adjustment knob is fixedly arranged at the outer end of the rotating shaft; the micro-feeding adjusting mechanism comprises a lead screw, the lead screw is installed on the installation plate and connected with the first fixing piece through a nut, and a feeding fine-adjustment knob is fixedly installed at the outer end of the lead screw.

4. The device for rapidly measuring the straightness of the guide rail installation surface according to claim 3, wherein: the horizontal fine adjustment mechanism also comprises a horizontal dial which is fixed on the mounting plate, and a horizontal pointer which is fixedly arranged on the rotating shaft is arranged outside the horizontal dial; the micro-feeding adjusting mechanism further comprises a feeding scale ring, the feeding scale ring is fixed on the mounting plate, and a feeding pointer fixedly mounted on the lead screw is arranged on the outer side of the feeding scale ring.

5. The device for rapidly measuring the straightness of a guide rail installation surface according to claim 3, wherein the device comprises:

the horizontal micro-adjusting mechanism of the first adjusting device rotates the first fixing piece along with the rotating shaft to realize the rotation of the first fixing piece in an angle in a plane and keep the horizontal relation between the surface to be measured of the guide rail and the first fixing piece, and the micro-feeding adjusting mechanism of the first adjusting device drives the second fixing piece to move by rotating the lead screw to adjust the distance between the first displacement sensor and the vertical mounting surface of the guide rail to be measured to be 0.4-0.6mm;

and a horizontal micro-adjusting knob of the second adjusting device enables the surface to be measured of the guide rail and the second fixing piece to keep a horizontal relation, and a micro-feeding adjusting mechanism of the second adjusting device adjusts the distance between the second displacement sensor and the horizontal mounting surface of the guide rail to be measured to be 0.5-08mm through screw feeding.

6. The device for rapidly measuring the straightness of the guide rail installation surface as claimed in claim 2, wherein: the second displacement sensor is in threaded connection with the second fixing piece, and the first displacement sensor is in a bonding connection mode with the second fixing piece.

7. The device for rapidly measuring the straightness of the guide rail installation surface according to claim 1, wherein: the bottom surface and the side wall of the sliding body are both provided with bearings, and the inner surfaces of the bottom surface and the side wall of the sliding body adopt grid structures.

8. A method for measuring the straightness of a guide rail installation surface according to any one of claims 1 to 7, wherein the method comprises the following steps: measuring by combining a photoelectric autocollimator, fixing a reflector on a bridge plate, placing the bridge plate at one end of a guide rail to be measured, starting to measure, dragging the bridge plate along the guide rail in an end-to-end connection manner at equal span, recording the inclination angle of the connecting line of each two adjacent points of a straight line to be measured relative to a main optical axis, and reading out the measured values delta z and delta x of the photoelectric autocollimator; the method specifically comprises the following steps:

(1) Adjusting the machine body of the equipment to be tested to be horizontal, and enabling the sliding body to move from the initial position of the installation surface of the guide rail to be tested to the final position at a constant speed;

(2) The method comprises the steps that a first displacement sensor and a second displacement sensor are combined with a photoelectric sensor and are matched with the photoelectric autocollimator to measure errors generated by a reference plane for measuring the linearity, the photoelectric sensor collects position information of a point to be measured on the side surface in the process that a sliding body moves from an initial position to a final position of a guide rail mounting surface to be measured, measurement data delta z 'of the first displacement sensor arranged in the vertical direction comprises a straightness error delta z of the guide rail mounting surface to be measured in the vertical direction and an error delta z generated by the reference plane for measuring the vertical linearity, measurement data delta x' of the second displacement sensor arranged towards the bottom surface comprises a horizontal straightness error delta x of the guide rail mounting surface to be measured and an error delta x generated by the reference plane for measuring the horizontal straightness, and at the moment, the data measured by the photoelectric collimator are regarded as the guide rail straightness errors delta z and delta x; therefore, the readings Δ z and Δ x of the photoelectric collimator are subtracted from the measurement data Δ z 'and Δ x' of the displacement sensor to calculate Δ z "and Δ x"; namely:

(3) Measuring delta z' at each position in the whole motion stroke _i And Δ x ″) _i I =1,2,3.. N, then Δ z ″ of corresponding points on the reference plane is fitted by a curve fitting method based on the principle of least squares _i And Δ x ″) _i Fitting is performed, and the fitting formula is as follows:

g (y) and h (y) are straightness errors of the reference plane in the vertical direction and the horizontal direction at the movement position y of the measured guide rail respectively, wherein

m is the highest order of the corresponding linearity error harmonic wave on the reference plane obtained by calculation, and the sampling theorem shows that when the number n of the calibration points is even, only the maximum number of the calibration points can be calculated

An order coefficient; when n is an odd number, at most, only m = (n-1)/2-order coefficient can be calculated, the fitting order is adjusted according to the actual situation, and when the order is reduced, the order of the model is not reduced when the standard deviation of the fitted curve compared with the linear interpolation method is not reduced; a. The _k ,B _k Is the k-th order error harmonic coefficient, C _k And

the amplitude and phase of the k-th order error harmonic;

(4) Solving for C _k And

by the formula:

due to the fact that

By

Obtaining:

using coordinate transformation, the following equation is established:

order:

X＝[A ₁ ,A ₂ ,...,A _m ,B ₁ ,B ₂ ,...,B _m ] ^T ，

convert it to matrix form:

the following is obtained by calculation by a least square method:

thereby obtaining the k-th order error harmonic coefficient A _k And B _k Further, the amplitude C is obtained _k And phase

(5) Finally, with the error compensation formula:

and obtaining the error g (y) generated by the linearity measurement of any j (j =1,2,3.) point on the reference plane in the whole displacement range through the fitted curve _j ) And h (y) _j ) Obtaining the straightness error of any point of the guide rail;

(6) Measuring point position information measured by the photoelectric sensor and the error value g (y) obtained in the step (6) _j ) And h (y) _j ) And drawing a linearity deviation curve graph of the side surface and the bottom surface, and obtaining the final linearity error of the mounting surface to be tested by using a minimum containment region method.

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