CN113251932B - A Displacement Measurement Method Integrating Confocal and Triangulation - Google Patents

Abstract

The invention discloses a displacement measurement method integrating a confocal method and a trigonometry. The existing displacement measurement mode has the contradiction between precision and measuring range. A focusing lens and a position sensitive element are arranged on one side of a probe of a laser confocal displacement sensor, the laser confocal displacement sensor carries out high-precision measurement during measurement to obtain a measured value, a triangulation displacement measurement system also carries out measurement on a laser incidence point, measurement data assist judges whether a measured point is in the range of the laser confocal displacement sensor, if the confocal displacement sensor exceeds the range, the triangulation displacement measurement system obtains the position value of the current measured point, then the position value is used for guiding the Z axis of a three-coordinate measuring machine to move along the direction of the Z coordinate axis, a measuring head device is enabled to return to the range of the laser confocal displacement sensor, and then measurement is continued. The invention can realize the expansion of the measuring range of the laser confocal displacement sensor under the condition of ensuring high-precision measurement.

Description

A Displacement Measurement Method Integrating Confocal and Triangulation

technical field

The invention belongs to the field of non-contact displacement measurement based on optical measurement, in particular to a displacement measurement method integrating confocal method and triangulation method.

Background technique

Confocal displacement measurement is a non-contact displacement measurement method based on spectral dispersion analysis. And the distance from each monochromatic light focal point to the measured object is different. When the measured surface is at a certain position within the measurement range, only the light of a certain wavelength is focused on the measured surface. Since the light of this wavelength satisfies the confocal condition, the reflected light can enter the spectrometer, while the light of other wavelengths, Most of the light cannot enter the spectrometer because it is out of focus on the surface being measured. By decoding the spectrometer to obtain the wavelength value at the maximum light intensity, the distance value corresponding to the target can be measured.

On this basis, the color coaxial confocal displacement meter developed by KEYENCE uses a color light source to replace the white light source used in the traditional confocal displacement measurement, which improves the luminous band width and can achieve high precision in a wider range of wavelengths. Measurement. The main principle is: first irradiate a blue laser beam to a phosphor capable of emitting red and green light at the same time to generate polychromatic light, and then transmit the polychromatic light to the probe through an optical fiber; Only the monochromatic light of a specific wavelength can be focused at the measured point; when receiving light, only the light focused on the surface of the measured object can be received and transmitted to the spectroscope to be decomposed by wavelength to obtain the corresponding measurement data. It adopts the straight-up and straight-down measurement method, which can achieve high-precision measurement on the surfaces of curved surfaces, pits, and various types of objects to be tested with small surface fluctuations.

However, in the field of displacement monitoring, measurement accuracy and range are often contradictory. Although the accuracy of confocal displacement measurement is high, its range is small, such as the products developed by KEYENCE: ultra-high-precision displacement meter CL-L015/CL-P015, its range is 2.6mm; shape measurement type displacement Meter CL-PT010, its range is 0.6mm. Therefore, when the surface of the measured object has a complex topography and large fluctuations, the confocal displacement measurement will easily lead to over-range phenomenon and terminate the measurement.

To solve this problem, in the field of displacement monitoring, there is a triangulation displacement measurement to make up for the shortcoming of the confocal displacement sensor with a small range. The main principle of the triangulation displacement measurement is: after the laser emitted by the laser is focused on the surface of the object to be measured through the focusing lens, the generated diffusely reflected light is received by the receiving lens, and converged to the position sensitive element (such as PSD, CMOS, CCD, etc.) to form a light spot , according to the triangular relationship formed between the measured point, the optical center of the receiving lens and the light spot on the sensitive element, the displacement value of the measured point can be obtained. However, compared with the confocal method displacement sensor, although the triangulation method laser displacement sensor has a larger range, its measurement accuracy is lower, and it may not meet the measurement requirements in some occasions requiring high-precision detection.

In order to solve the contradiction between measurement accuracy and range, the commonly used method is to use large-range and high-precision sensors for repeated measurement. Accurate sensor for secondary measurement. This type of measurement method can solve the contradiction between range and accuracy to a certain extent, but when applied to the production site, first, multiple measurements reduce the production takt, cannot meet the production site's requirements for measurement efficiency, and increase the time cost; The second is to use sensors with large range and high precision respectively, and two kinds of sensors need to be used respectively, which increases the measurement cost.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art, the present invention aims to provide a displacement measurement method integrating confocal method and triangulation method. By installing a focusing lens and a position sensitive element on one side of the laser confocal displacement sensor probe, the confocal displacement is The incident laser of the sensor, the focusing lens and the position sensitive element constitute a triangulation displacement measurement system. During the measurement, the laser confocal displacement sensor is used for high-precision measurement to obtain the final measurement value. At the same time, the triangulation displacement measurement system also measures the laser incident point. The measurement data can assist in real-time judgment of whether the measured point is in the laser confocal displacement sensor. Within the range (that is, whether the laser confocal displacement sensor is out of focus). If the confocal displacement sensor is out of range, the triangulation displacement measurement system obtains the position value of the current measurement point, and then uses the position value to guide the Z axis of the three-coordinate measuring machine to move along the Z coordinate axis, so as to adjust the probe device in the Z coordinate direction. position on the axis, return the probe assembly to the range of the laser confocal displacement sensor, and then continue the measurement. The invention can realize the expansion of the range of the laser confocal displacement sensor at the same time under the condition of ensuring high-precision measurement.

In order to achieve the above object, the present invention adopts the following technical solutions:

A displacement measurement method integrating confocal method and triangulation method of the present invention is specifically as follows:

Step 1: Build a displacement measuring probe device integrating confocal method and triangulation method; the displacement measuring probe device integrating confocal method and triangulation method includes a laser confocal displacement sensor probe, a probe fixing fixture 2, and a probe fixing fixture 1. Probe panel, fixing base, position sensitive element, lens holder and focusing lens; the probe fixing fixture 1 is fixed with the probe fixing fixture 2, and clamps the laser confocal displacement sensor probe; the probe fixing fixture 1 is connected with the measuring The head panel is fixed. The position sensitive element is fixed on the fixed seat, and the fixed seat is fixed with the panel of the measuring head. The focusing lens is fixed on the lens holder, and the lens holder is fixed with the probe panel. The laser confocal displacement sensor probe is connected with the optical unit of the laser confocal displacement sensor body and the controller to form a laser confocal displacement sensor; the measurement light emitted by the laser confocal displacement sensor probe is generated by the optical unit of the laser confocal displacement sensor body. It is transmitted to the laser confocal displacement sensor probe through the optical fiber; the central axis of the measuring light emitted by the laser confocal displacement sensor probe and the central axis of the focusing lens are located in the same plane. The signal output end of the position sensitive element is connected with the controller. The laser confocal displacement sensor, the focusing lens and the position sensitive element form a triangulation displacement measurement system.

Step 2: Fix the probe panel on the Z-axis of the CMM, and make the central axis of the measurement light emitted by the laser confocal displacement sensor probe parallel to the Z-axis of the CMM.

Step 3: Calibrate the working range s ₁ s ₂ of the position sensitive element within the range of the laser confocal displacement sensor, and calibrate the working range of the triangulation displacement measurement system.

Step 4: Place the object to be measured in the measurement area of the CMM platform, and establish a measurement coordinate system with the X, Y, and Z coordinate axes of the CMM.

Step 5: The Z-axis of the CMM is translated along the Z-coordinate axis, and the position of the probe panel on the Z-coordinate axis is adjusted so that the light spot formed on the position sensitive element after the focusing lens focuses the diffusely reflected light on the surface of the object to be measured The position point is at s ₀ , and the Z coordinate value Z ₀ of the Z-axis of the three-coordinate measuring machine at this time is recorded, and s ₀ is the center position of the working range s ₁ s ₂ .

Step 6: The Z axis of the CMM translates along the X or Y coordinate axis, driving the laser confocal displacement sensor probe to scan and measure the surface of the object to be measured; when measuring the point i to be measured, first obtain the triangulation displacement measurement system and determine whether the spot focused by the focusing lens at the point i to be measured is within the range s ₁ s ₂ , if it is within the range s ₁ s ₂ , then save the measurement coordinate value of the laser confocal displacement sensor at this time ( X _i ,Y _i ,Z _i ), where i=1,2,3...,n, n is the total number of points to be measured in the process of scanning and measuring the surface of the object to be measured; The focused spot is located in the range s ₂ s ₂ ′, then the Z-axis drive probe panel of the CMM moves down along the Z-coordinate axis until the spot position focused by the focusing lens returns to the range s ₁ s ₂ , and Record the distance Δz that the CMM moves along the Z coordinate axis, save the measured coordinate values (X _i , Y _i , Z _i -Δz) of the laser confocal displacement sensor at this time, and save the Z axis of the CMM after completion. Move up Δz along the Z coordinate axis to reset; if the spot focused by the focusing lens at the point i to be measured is within the range s ₁ s ₁ ′, the Z axis of the CMM drives the probe panel to move up along the Z coordinate axis direction , until the focus spot position of the focusing lens returns to the range s ₁ s ₂ , and record the distance Δz that the CMM moves along the Z coordinate axis, and save the measured coordinate values of the laser confocal displacement sensor at this time (X _i , Y _i ,Z _i +Δz), after saving, the Z-axis of the CMM moves down Δz along the Z-coordinate axis to reset.

Step 7: Repeat the point-by-point scanning measurement process in Step 6 until the scanning measurement of the entire surface of the object to be measured is completed.

Preferably, the process of calibrating the working range of the position sensitive element within the range of the laser confocal displacement sensor is as follows:

①The Z axis of the CMM is translated along the Z coordinate axis, so that the output measurement value of the laser confocal displacement sensor is h ₀ at the midpoint of the range, and the spot position point on the position sensitive element is recorded as s ₀ . Then move the Z-axis of the coordinate measuring machine downward, so that the output measurement value of the laser confocal displacement sensor is the minimum range h ₁ , and record the spot position on the position sensitive element as s ₁ .

② The Z-axis of the coordinate measuring machine is moved upward, so that the output measurement value of the laser confocal displacement sensor is the maximum range h ₂ , and the spot position on the position sensitive element is recorded as s ₂ , then the laser confocal displacement The working range of the calibrated position sensitive element is s ₁ s ₂ within the range of the sensor.

Preferably, the working range calibration process of the triangulation displacement measurement system is as follows:

① The Z-axis of the CMM translates along the Z-coordinate axis, so that after the focusing lens focuses the diffusely reflected light on the surface of the object to be measured, a light spot is formed on the position sensitive element at s ₀ . Then move the Z-axis of the coordinate measuring machine downward, when the focusing lens focuses the diffuse reflection light on the surface of the object to be measured, and the light spot formed on the position sensitive element is located at the lower limit position s ₁ ′ of the working range of the position sensitive element , and record the downward movement distance h ₁ ′ of the CMM.

② The Z axis of the CMM moves upward, when the focusing lens focuses the diffuse reflection light on the surface of the object to be measured, and the light spot formed on the position sensitive element is at the upper limit position point s ₂ ′ of the working range of the position sensitive element, Record the upward movement distance h ₂ ′ of the CMM, then the maximum working range of the position sensitive element is s ₁ ′s ₂ ′, and the working range of the triangulation displacement measuring system is h′=h ₁ ′-h ₂ ′.

Preferably, the output value of the triangulation displacement measurement system is calculated using the triangulation displacement measurement principle, and the calculation formula is as follows:

In the formula, α is the angle between the central axis of the measuring light emitted by the laser confocal displacement sensor probe and the central axis of the focusing lens; β is the angle between the surface of the position sensitive element and the central axis of the focusing lens; l ₁ is the distance from the center of the focusing lens to the central axis of the measuring light emitted by the probe of the laser confocal displacement sensor when the output measurement value of the laser confocal displacement sensor is the midpoint value h ₀ of the range; l ₂ is the focus when the spot position is at s ₀ The distance from the center of the lens to the spot position point; Δs is the distance between the spot position point of the measured point on the position sensitive element relative to the spot position point s ₀ ; Δh is the real-time measurement point of the triangulation displacement measurement system relative to the range of the laser confocal displacement sensor The distance of the point value h ₀ ; when the measured point is above the h ₀ point, ± takes the positive sign, otherwise, the ± takes the negative sign.

Preferably, when the laser confocal displacement sensor is defocused at the near end of the point to be measured, the distance Δz that the Z axis of the CMM moves up along the Z coordinate axis satisfies the following conditions:

Δh-(h ₁ -h ₀ )≤Δz≤Δh+(h ₀ -h ₂ )

Preferably, when the laser confocal displacement sensor is out of focus at the far end of the point to be measured, the distance Δz that the Z axis of the CMM moves down along the Z coordinate axis satisfies the following conditions:

Δh-(h ₀ -h ₂ )≤Δz≤Δh+(h ₁ -h ₀ ).

The beneficial effects that the present invention has are:

1. The present invention integrates the confocal displacement measurement and the triangulation displacement measurement. In the actual measurement process, the triangulation displacement measurement system is used to determine whether the laser confocal displacement sensor has an overrange phenomenon, and the data is adjusted according to the triangulation measurement. The Z-axis coordinate of the measuring device makes the laser confocal displacement sensor return to the confocal measurement area, thereby expanding the measurement range of the laser confocal displacement sensor, and can realize fast and high-speed measurement of complex surfaces with holes, holes and sudden changes. Accurate non-contact measurement.

2. The measurement principle of the present invention is simple, the measurement cost is low, and the operation is convenient, and is suitable for high-precision, large-range measurement scenarios.

Description of drawings

1 is a perspective view of the overall structure of the displacement measuring probe device in the present invention;

Fig. 2 is the assembly schematic diagram of probe fixing jig 1 and probe fixing jig 2 in the present invention;

Fig. 3 is the optical path schematic diagram of the displacement measuring probe device in the present invention;

Fig. 4 is the principle diagram of the trigonometric displacement measurement adopted in the present invention;

FIG. 5 is a schematic diagram of the work flow of the present invention.

In the picture: 1. Laser confocal displacement sensor probe, 2. Probe fixing fixture 2, 3. Screws, 4. Probe fixing fixture 1, 5. The first bolt group, 6. Probe panel, 6-1, connecting rod, 7. Fixed seat, 8. Second bolt group, 9. Position sensitive element, 10, Third bolt group, 11. Lens holder, 12. Focusing lens.

Detailed ways

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

As shown in Figure 4 and Figure 5, a displacement measurement method integrating confocal method and triangulation method is as follows:

Step 1: As shown in Figures 1, 2 and 3, construct a displacement measurement probe device integrating confocal method and triangulation method; the displacement measurement probe device integrating confocal method and triangulation method includes laser confocal displacement sensor probe 1, Probe fixing fixture 2 2, probe fixing fixture 1 4, probe panel 6, fixing base 7, position sensitive element 9, lens holder 11 and focusing lens 12; probe fixing fixture 1 4 and probe fixing fixture 2 2 are connected by screws 3 A probe fixing fixture is formed, and the laser confocal displacement sensor probe 1 is clamped; the probe fixing fixture 1 4 is connected with the probe panel 6 through the first bolt group 5 . The position sensitive element 9 (the position sensitive element 9 is preferably a linear array CMOS image sensor or a linear array CCD element) is fixed on the fixing base 7 , and the fixing base 7 is connected with the probe panel 6 through the second bolt group 8 . The focusing lens 12 is fixed on the lens holder 11, and the lens holder 11 is connected with the probe panel 6 (preferably, the probe panel 6 is provided with an integrally formed connecting rod 6-1) through a third bolt group 10. The laser confocal displacement sensor probe 1 is connected with the optical unit and the controller of the laser confocal displacement sensor body to form a laser confocal displacement sensor; the measurement light emitted by the laser confocal displacement sensor probe 1 is transmitted by the optical unit of the laser confocal displacement sensor body. generated and transmitted to the laser confocal displacement sensor probe 1 through an optical fiber; the central axis of the measuring light emitted by the laser confocal displacement sensor probe 1 and the central axis of the focusing lens 12 are located in the same plane. The focusing lens 12 can form a light spot on the position sensitive element 9 after focusing the diffusely reflected light on the surface of the measured object; the signal output end of the position sensitive element 9 is connected to the controller. The laser confocal displacement sensor, the focusing lens 12 and the position sensitive element 9 constitute a triangulation displacement measurement system.

Step 2: Fix the probe panel 6 on the Z-axis of the CMM, and make the central axis of the measuring light emitted by the laser confocal displacement sensor probe 1 parallel to the Z-axis of the CMM.

Step 3: calibrate the working range s ₁ s ₂ of the position sensitive element 9 within the range of the laser confocal displacement sensor, and calibrate the working range of the triangulation displacement measurement system.

Step 4: Place the object to be measured in the measurement area of the CMM platform, and establish a measurement coordinate system with the X, Y, and Z coordinate axes of the CMM.

Step 5: The Z-axis of the CMM is translated along the Z-coordinate axis, and the position of the probe panel 6 on the Z-coordinate axis is adjusted, so that the focusing lens 12 focuses the diffusely reflected light on the surface of the object to be measured, and then adjusts the position sensitive element 9. The position of the formed light spot is at s ₀ , and the Z coordinate value Z ₀ of the Z-axis of the three-coordinate measuring machine at this time is recorded, and s ₀ is the center position of the working range s ₁ s ₂ .

Step 6: The Z axis of the CMM translates along the X or Y coordinate axis, and drives the laser confocal displacement sensor probe 1 to scan and measure the surface of the object to be measured; when measuring the point i to be measured, first obtain the triangulation displacement measurement The output value of the system, and determine whether the spot focused by the focusing lens 12 at the point i to be measured is within the range s ₁ s ₂ , if it is within the range s ₁ s ₂ , then save the measurement coordinates of the laser confocal displacement sensor at this time value (X _i , Y _i , Z _i ), where X _i is the X coordinate value of the point i to be measured in the measurement coordinate system, Y _i is the Y coordinate value of the point i to be measured in the measurement coordinate system, Z _i is the Z coordinate value of the point i to be measured in the measurement coordinate system, i=1, 2, 3..., n, n is the total number of points to be measured during the scanning measurement of the surface of the measured object; if the point to be measured i If the spot focused by the focusing lens 12 is located in the range s ₂ s ₂ ′, it is considered that the laser confocal displacement sensor probe 1 is too far away from the surface of the object to be measured (the far end is defocused) and has exceeded its range, and then the three-coordinate measurement The Z-axis of the machine drives the probe panel 6 to move down along the Z-axis direction until the spot position focused by the focusing lens 12 returns to the range s ₁ s ₂ , and records the distance Δz that the CMM moves along the Z-axis direction , save the measured coordinate values (X _i , Y _i , Z _i -Δz) of the laser confocal displacement sensor at this time, after the save, the Z axis of the CMM moves up Δz along the Z coordinate axis to reset, ready for the next point Measurement; if the light spot focused by the focusing lens 12 at the point i to be measured is within the range s ₁ s ₁ ', it is considered that the laser confocal displacement sensor probe 1 is too close to the surface of the measured object (the near end is out of focus) and has exceeded its range, and then the Z-axis of the CMM drives the probe panel 6 to move up along the Z-coordinate axis until the focus spot position of the focusing lens 12 returns to the range s ₁ s ₂ , and record the CMM along the Z-coordinate The distance Δz moved in the axis direction, save the measured coordinate values (X _i , Y _i , Z _i +Δz) of the laser confocal displacement sensor at this time, after saving, the Z axis of the CMM moves down along the Z coordinate axis direction Δz Reset, ready for the next point measurement.

Step 7: Repeat the point-by-point scanning measurement process in Step 6 until the scanning measurement of the entire surface of the object to be measured is completed.

As a preferred embodiment, the process of calibrating the working range of the position sensitive element 9 within the range of the laser confocal displacement sensor is as follows:

① The Z axis of the three-coordinate measuring machine is translated along the Z coordinate axis, so that the output measurement value of the laser confocal displacement sensor is h ₀ at the midpoint of the range, and the spot position point on the position sensitive element 9 at this time is recorded as s ₀ . Then move the Z-axis of the coordinate measuring machine downward, so that the output measurement value of the laser confocal displacement sensor is the minimum value h ₁ of the range (the near-end defocus critical point), and record the spot position point on the position sensitive element 9 at this time. is s ₁ .

② The Z axis of the coordinate measuring machine is moved upward, so that the output measurement value of the laser confocal displacement sensor is the maximum range h ₂ (the critical point of far-end defocusing), and the spot position point on the position sensitive element 9 is recorded as s ₂ , the working range of the position sensitive element 9 is calibrated as s ₁ s ₂ within the range of the laser confocal displacement sensor.

As a preferred embodiment, the working range calibration process of the triangulation displacement measurement system is as follows:

①The Z-axis of the CMM translates along the Z-coordinate axis, so that after the focusing lens 12 focuses the diffusely reflected light on the surface of the object to be measured, a spot is formed on the position sensitive element 9 at s ₀ . Then move the Z-axis of the three-coordinate measuring machine downward, when the focusing lens 12 focuses the diffusely reflected light on the surface of the object to be measured, and the light spot formed on the position sensitive element 9 is located at the lower limit position point s of the working range of the position sensitive element 9 ₁ ′, record the downward movement distance h ₁ ′ of the CMM.

② The Z-axis of the three-coordinate measuring machine moves upward, when the focusing lens 12 focuses the diffusely reflected light on the surface of the object to be measured, and the light spot formed on the position sensitive element 9 is located at the upper limit position point s ₂ of the working range of the position sensitive element 9 ', record the upward moving distance h ₂ ' of the CMM, then the maximum working range of the position sensitive element 9 is s ₁ 's ₂ ', and the working range of the triangulation displacement measuring system is h'=h ₁ '-h ₂ '.

As a preferred embodiment, the output value of the triangulation displacement measurement system is calculated using the triangulation displacement measurement principle, and the calculation formula is as follows:

In the formula, α is the angle between the central axis of the measurement light emitted by the laser confocal displacement sensor probe 1 and the central axis of the focusing lens 12 ; β is the angle between the surface of the position sensitive element 9 and the central axis of the focusing lens 12 angle; _l1 is the distance from the center of the focusing lens 12 to the central axis of the measurement light emitted by the laser confocal displacement sensor probe 1 when the output measurement value of the laser confocal displacement sensor is the midpoint value _h0 of the range; _l2 is the position of the light spot At s ₀ , the distance from the center of the focusing lens 12 to the spot position; Δs is the distance between the spot position of the measured point on the position sensitive element 9 relative to the spot position s ₀ ; Δh is the real-time measurement point of the triangulation displacement measurement system The distance from the mid-point value h ₀ of the laser confocal displacement sensor; when the measured point is located above the h ₀ point, ± takes a positive sign, otherwise, ± takes a negative sign.

As a preferred embodiment, when the laser confocal displacement sensor is defocused at the near end of the real-time measurement point, the distance Δz that the Z-axis of the CMM moves up along the Z-coordinate axis satisfies the following conditions:

Δh-(h ₁ -h ₀ )≤Δz≤Δh+(h ₀ -h ₂ )

As a preferred embodiment, when the laser confocal displacement sensor is defocused at the far end of the real-time measurement point, the distance Δz that the Z-axis of the CMM moves down along the Z-coordinate axis satisfies the following conditions:

Δh-(h ₀ -h ₂ )≤Δz≤Δh+(h ₁ -h ₀ ) .

Claims (6)

1. a displacement measurement method integrating confocal method and trigonometry, is characterized in that: the method is specifically as follows: Step 1: Build a displacement measuring probe device integrating confocal method and triangulation method; the displacement measuring probe device integrating confocal method and triangulation method includes a laser confocal displacement sensor probe, a probe fixing fixture 2, and a probe fixing fixture 1. Probe panel, fixing base, position sensitive element, lens holder and focusing lens; the probe fixing fixture 1 is fixed with the probe fixing fixture 2, and clamps the laser confocal displacement sensor probe; the probe fixing fixture 1 is connected with the measuring The head panel is fixed; the position sensitive element is fixed on the fixed seat, and the fixed seat is fixed with the probe panel; the focusing lens is fixed on the lens holder, and the lens holder is fixed with the probe panel; laser confocal displacement sensor The probe is connected with the optical unit of the laser confocal displacement sensor body and the controller to form a laser confocal displacement sensor; the measurement light emitted by the laser confocal displacement sensor probe is generated by the optical unit of the laser confocal displacement sensor body, and transmitted to the optical fiber through the optical fiber. The laser confocal displacement sensor probe; the central axis of the measuring light emitted by the laser confocal displacement sensor probe and the central axis of the focusing lens are located in the same plane; the signal output end of the position sensitive element is connected with the controller; the laser confocal displacement The sensor, focusing lens and position sensitive element form a triangulation displacement measurement system; Step 2: Fix the probe panel on the Z-axis of the CMM, and make the central axis of the measurement light emitted by the laser confocal displacement sensor probe parallel to the Z-axis of the CMM; Step 3: calibrate the working range s ₁ s ₂ of the position sensitive element within the range of the laser confocal displacement sensor, and calibrate the working range of the triangulation displacement measurement system; Step 4: Place the object to be measured in the measurement area of the CMM platform, and establish a measurement coordinate system with the X, Y, Z coordinate axes of the CMM; Step 5: The Z-axis of the CMM is translated along the Z-coordinate axis, and the position of the probe panel on the Z-coordinate axis is adjusted so that the light spot formed on the position sensitive element after the focusing lens focuses the diffusely reflected light on the surface of the object to be measured The position point is at s ₀ , and the Z coordinate value Z ₀ of the Z-axis of the three-coordinate measuring machine at this time is recorded, and s ₀ is the center position of the working range s ₁ s ₂ ; Step 6: The Z axis of the CMM translates along the X or Y coordinate axis, driving the laser confocal displacement sensor probe to scan and measure the surface of the object to be measured; when measuring the point i to be measured, first obtain the triangulation displacement measurement system and determine whether the spot focused by the focusing lens at the point i to be measured is within the range s ₁ s ₂ , if it is within the range s ₁ s ₂ , then save the measurement coordinate value of the laser confocal displacement sensor at this time ( X _i ,Y _i ,Z _i ), where i=1,2,3...,n, n is the total number of points to be measured in the process of scanning and measuring the surface of the object to be measured; The focused light spot is located in the range s ₂ s' ₂ , then the Z-axis drive probe panel of the CMM moves down along the Z-coordinate axis until the spot position focused by the focusing lens returns to the range s ₁ s ₂ , and Record the distance Δz that the CMM moves along the Z coordinate axis, save the measured coordinate values (X _i , Y _i , Z _i -Δz) of the laser confocal displacement sensor at this time, and save the Z axis of the CMM after completion. Move up Δz along the Z coordinate axis to reset; if the light spot focused by the focusing lens at the point i to be measured is within the range s ₁ s′ ₁ , the Z axis of the CMM drives the probe panel to move up along the Z coordinate axis direction , until the focus spot position of the focusing lens returns to the range s ₁ s ₂ , and record the distance Δz that the CMM moves along the Z coordinate axis, and save the measured coordinate values of the laser confocal displacement sensor at this time (X _i , Y _i ,Z _i +Δz), after saving, the Z axis of the CMM moves down by Δz along the Z coordinate axis to reset; Step 7: Repeat the point-by-point scanning measurement process in Step 6 until the scanning measurement of the entire surface of the object to be measured is completed. 2. the displacement measuring method of a kind of integrated confocal method and trigonometry according to claim 1, is characterized in that: the process of calibrating the position sensitive element working range in the laser confocal displacement sensor range is as follows: ①The Z axis of the three-coordinate measuring machine is translated along the Z coordinate axis, so that the output measurement value of the laser confocal displacement sensor is h ₀ at the midpoint of the range, and the spot position point on the position sensitive element at this time is recorded as s ₀ ; The Z axis of the coordinate measuring machine is moved downward, so that the output measurement value of the laser confocal displacement sensor is the minimum range h ₁ , and the spot position point on the position sensitive element is recorded as s ₁ ; ② The Z-axis of the coordinate measuring machine is moved upward, so that the output measurement value of the laser confocal displacement sensor is the maximum range h ₂ , and the spot position on the position sensitive element is recorded as s ₂ , then the laser confocal displacement The working range of the calibrated position sensitive element is s ₁ s ₂ within the range of the sensor. 3. the displacement measuring method of a kind of integrated confocal method and trigonometry according to claim 1, is characterized in that: the working range calibration process of trigonometry displacement measuring system is specifically as follows: ① The Z-axis of the CMM is translated along the Z-coordinate axis, so that after the focusing lens focuses the diffusely reflected light on the surface of the object to be measured, a light spot is formed on the position sensitive element at s ₀ ; then the Z-axis of the CMM is The axis moves downward, when the focusing lens focuses the diffuse reflection light on the surface of the object to be measured, and the light spot formed on the position sensitive element is located at the lower limit position point s' ₁ of the working range of the position sensitive element, record the downward movement of the CMM The moving distance h′ ₁ ; ② The Z axis of the CMM moves upward, when the focusing lens focuses the diffuse reflection light on the surface of the object to be measured, and the light spot formed on the position sensitive element is located at the upper limit position point s' ₂ of the working range of the position sensitive element, Record the distance h' ₂ that the CMM moves upward, then the maximum working range of the position sensitive element is s' ₁ s' ₂ , and the working range of the triangulation displacement measuring system is h'=h' ₁ -h' ₂ . 4. the displacement measurement method of a kind of integrated confocal method and trigonometry according to claim 1, is characterized in that: the output value of trigonometry displacement measurement system adopts trigonometry displacement measurement principle to calculate, and the calculation formula is as follows:

In the formula, α is the angle between the central axis of the measuring light emitted by the laser confocal displacement sensor probe and the central axis of the focusing lens; β is the angle between the surface of the position sensitive element and the central axis of the focusing lens; l ₁ is the distance from the center of the focusing lens to the central axis of the measuring light emitted by the probe of the laser confocal displacement sensor when the output measurement value of the laser confocal displacement sensor is the midpoint value h ₀ of the range; l ₂ is the focus when the spot position is at s ₀ The distance from the center of the lens to the spot position point; Δs is the distance between the spot position point of the measured point on the position sensitive element relative to the spot position point s ₀ ; Δh is the real-time measurement point of the triangulation displacement measurement system relative to the range of the laser confocal displacement sensor The distance of the point value h ₀ ; when the measured point is above the h ₀ point, ± takes the positive sign, otherwise, the ± takes the negative sign. 5. the displacement measuring method of a kind of integrated confocal method and trigonometry according to claim 2, it is characterized in that: when the laser confocal displacement sensor is defocused at the near end of the point to be measured, the Z axis of the coordinate measuring machine is along the The distance Δz moved up by the Z coordinate axis satisfies the following conditions: Δh-(h ₁ -h ₀ )≤Δz≤Δh+(h ₀ -h ₂ ) Among them, Δh is the distance between the real-time measurement point of the triangulation displacement measurement system and the mid-point value h ₀ of the laser confocal displacement sensor. 6. the displacement measuring method of a kind of integrated confocal method and trigonometry according to claim 2, it is characterized in that: when the laser confocal displacement sensor is out of focus at the far end of the point to be measured, the Z axis of the coordinate measuring machine is along the The distance Δz that the Z coordinate axis moves down satisfies the following conditions: Δh-(h ₀ -h ₂ )≤Δz≤Δh+(h ₁ -h ₀ ) Among them, Δh is the distance between the real-time measurement point of the triangulation displacement measurement system and the mid-point value h ₀ of the laser confocal displacement sensor.

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