CN114877840B - Calibration device and calibration method for electric trigger type soft probe - Google Patents

Abstract

The invention relates to an electric trigger type soft measuring head calibration device and a calibration method, wherein the device comprises a fixing component, a simulation test component and two displacement sensors, wherein the electric trigger type soft measuring head to be measured is fixed through the fixing component, the electric trigger type soft measuring head is tested by using the test simulation component, the motion of a measured object is simulated through a pushing part, two test positions which move together with the pushing part are arranged on the pushing part, the displacement of the two test positions is detected through the displacement sensors, and the calibration of the electric trigger type soft measuring head can be completed by calculating the test results of the two displacement sensors. Compared with the prior art, the test bit can reflect the rotation condition of the pushing part, and the two test bits are respectively arranged on two sides of the probe to maximally eliminate errors generated by rotation of the pushing part, so that the influence of Abbe errors on a calibration result is maximally eliminated, and the calibration result is more accurate.

Description

Calibration device and calibration method for electric trigger type soft probe

technical field

The invention relates to the technical field of precision measurement, in particular to an electric trigger type soft probe calibration device and a calibration method.

Background technique

High-efficiency and high-precision machining technology has gradually become an important factor in judging the level of a country's modern industrial technology. Establishing an in-situ measurement system and realizing the integration of digital design, processing and measurement is an effective way to improve the precision and efficiency of complex precision parts manufacturing. Compared with non-contact measurement methods, contact measurement has the advantages of high precision, strong stability, and strong adaptability to the measurement environment. At present, contact measurement technology has been widely used in on-site measurement systems.

The electric trigger soft probe is a common contact measurement. From the time when the ball touches the surface of the workpiece to be measured to when the sensor generates an electrical signal, there is a certain relative displacement between the probe and the workpiece to be measured. The resulting measurement error is called "pre-travel error". The main error source of the electric trigger soft probe is the pre-travel amount under different trigger angles. Therefore, it is of great significance to improve the measurement accuracy and reliability of the measurement results by performing a calibration test on the pre-travel amount of the electric trigger soft probe at each trigger angle and determining a compensation method for the in-position measurement error of the electric trigger soft probe. .

Nowadays, many scholars have done a lot of research on the calibration of electric trigger soft probe. The trigger deformation process of the probe is studied, and the trigger force and actual deformation of different types of probes are studied. In 2021, Yang Yanling and others designed an optimization scheme for the structure and size of the touch probe, and established a calibration model of the touch probe by using the coordinate transformation theory and the least square method principle, and carried out calibration experiments. However, none of the existing studies considered the influence of the Abbe error generated during the calibration process on the calibration results.

Contents of the invention

In view of this, it is necessary to provide an electric trigger type soft probe calibration device and a calibration method to solve the problem that the existing calibration methods do not take into account the influence of the Abbe error.

In order to achieve the above-mentioned technical purpose, the present invention has taken the following technical solutions:

In the first aspect, the present invention provides an electric trigger type soft probe calibration device, which is used for calibrating the electric trigger type soft probe. The electric trigger type soft probe includes a probe and a measuring ball, and the measuring ball Installed on the end of the probe, including:

Fixing components, connecting and fixing the electric trigger type soft probe;

The test simulation component is connected to the fixed component, the test simulation component includes a movable push part, the push part abuts against the measuring ball, two test positions are formed on the push part, and the two test positions are formed on the push part. The test positions are respectively located on both sides of the probe;

Two displacement sensors, both of which are connected to the fixing assembly, are used to detect the displacement of the two test positions respectively.

Further, the test simulation component includes an inclined block micrometer, the inclined block of the inclined block micrometer is the pushing part, and the inclined surface of the inclined block in the inclined block micrometer abuts against the The measuring ball, the two test positions are located on the inclined surface of the inclined block in the inclined block micrometer.

Further, the displacement sensor is a contact sensor, the detection end of the displacement sensor abuts against the pushing part, and the moving direction of the pushing part when pushing the measuring ball is perpendicular to the extending direction of the probe, so The detecting direction of the displacement sensor is the same as the moving direction when the pushing part pushes the measuring ball.

Further, the connecting line of the two test positions is perpendicular to the extending direction of the probes, and the distances from the two test positions to the probes are the same.

Further, the fixing assembly includes a locking part and a rotating part, the locking part is connected to the electric trigger soft probe, the rotating part is connected to the locking part, and is used to drive the locking part to drive the The electric trigger type soft measuring head rotates, and the rotation axis of the rotating part coincides with the axis of the probe.

Further, the fixing assembly further includes two magnetic watch bases, and the two magnetic watch bases are respectively connected to the two displacement sensors.

Further, the fixed assembly further includes a workbench, and the test simulation assembly, the rotating part and the magnetic watch base are all connected to the workbench.

In the second aspect, the present invention also provides an electric trigger type soft probe calibration method, using any of the above electric trigger type soft probe calibration devices, including:

Step 1. Use the pushing part to push the measuring ball, obtain the displacement of the two test positions on the pushing part, and reset the pushing part;

Step 2, repeating the step 1 multiple times to obtain a set of displacements;

Step 3, adjusting the pose of the electric trigger type soft probe, repeating the step 2 to obtain multiple sets of displacements;

Step 4. Obtain calibration parameters according to multiple sets of displacements;

Step 5: Calibrate the electric trigger type soft probe according to the calibration parameters.

Further, the adjustment of the pose of the electric trigger soft probe includes:

Rotate the electric trigger type soft probe along the axis of the probe until the electric trigger type soft probe reaches the set position.

Further, the displacement is the displacement of the test position along the moving direction of the pushing part, and the calibration parameters include pre-travel, trigger stability parameters and overall stability parameters.

The invention provides an electric trigger type soft probe calibration device and a calibration method, which fixes the electric trigger type soft probe to be measured through a fixing component, uses a test simulation component to test the electric trigger type soft probe, and pushes the The part simulates the movement of the object to be measured, and there are two test positions that move with it on the push part. The displacement of the two test positions is detected by the displacement sensor, and the electric trigger type can be completed by calculating the test results of the two displacement sensors. Calibration of soft probes. Compared with the prior art, the test position in the present invention can reflect the rotation of the pushing part, and the two test positions are respectively arranged on both sides of the probe to maximize the elimination of the error caused by the rotation of the pushing part and maximize the Eliminate the influence of Abbe error on the calibration results, making the calibration results more accurate.

Description of drawings

Fig. 1 is the structural schematic diagram of an embodiment of the electric trigger type soft probe calibration device provided by the present invention;

Fig. 2 is a method flow chart of an embodiment of an electric trigger type soft probe calibration method provided by the present invention;

Fig. 3 is a schematic diagram of the structure of the electric trigger type soft probe calibration device provided by the present invention during detection.

Detailed ways

Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the application and together with the embodiments of the present invention are used to explain the principle of the present invention and are not intended to limit the scope of the present invention.

In the description of the present application, "plurality" means two or more, unless otherwise specifically defined.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

The trigger probe is a device used to detect the movement of machine tools or some other objects. Its working principle is roughly as follows: there is a closed active circuit inside the probe, which is connected with a special trigger mechanism. When the mechanism produces a trigger action, it will cause a change in the state of the circuit and send out an audible and visual signal to indicate the working status of the probe. The only condition for the trigger mechanism to trigger action is that the stylus of the stylus swings slightly or moves toward the inside of the stylus. The surface contact of the workpiece (any solid material) will cause the stylus to vibrate or move slightly, which will immediately cause the probe to generate sound and light signals, indicating its working status.

During the process from when the measuring ball touches the surface of the workpiece to be measured to when the sensor generates electrical signals, there is a certain relative displacement between the probe and the workpiece to be measured, and the resulting measurement error is called "pre-travel error". The main error source of the soft probe is the pre-travel amount under different trigger angles. Therefore, the pre-travel amount of the electric trigger soft probe under each trigger angle is calibrated and tested to determine a compensation method for the in-position measurement error of the electric trigger soft probe.

However, the existing calibration methods do not consider the influence of the Abbe error, which makes the calibration results not accurate enough. The Abbe error means that the axis of the measuring instrument and the axis of the workpiece to be measured must be on the same straight line, otherwise an error will occur. This error is called is the Abbe error. During the calibration process of the electric trigger soft probe, because it cannot be guaranteed that the parts used to trigger the electric trigger soft probe can only move in a straight line, it usually rotates slightly, so that the Abbe error occurs during the calibration process. inevitable.

Adopt following mode in the present invention to eliminate Abbe's error:

The present invention provides a calibration device and a calibration method for an electric trigger type soft probe, which will be described respectively below.

As shown in FIG. 1 , a specific embodiment of the present invention discloses an electric trigger type soft probe calibration device for calibrating an electric trigger type soft probe 100 . The electric trigger type soft probe 100 includes A probe 101 and a measuring ball 102 , the measuring ball 102 is installed at the end of the probe 101 . The electrical trigger type soft probe calibration device includes a fixed component 1 , a test simulation component 2 and a displacement sensor 3 . Wherein the fixed component 1 is connected and fixed to the electric trigger type soft probe 100, the test simulation component 2 is connected to the fixed component 1, and the test simulation component 2 includes a movable pushing part 21, and the pushing part 21 abuts against The measuring ball 102 and the pushing part 21 are formed with two test positions, and the two test positions are respectively located on two sides of the probe 101 . There are two displacement sensors 3, and the two displacement sensors 3 are both connected to the fixing assembly 1, and are respectively used to detect the displacement of the two test positions.

The present invention provides an electric trigger type soft probe calibration device and calibration method, which fixes the electric trigger type soft probe 100 to be measured through the fixing component 1, and uses the test simulation component 2 to test the electric trigger type soft probe 100 , which simulates the movement of the object to be measured through the pusher 21. There are two test positions moving with it on the pusher 21. The displacement of the two test positions is detected by the displacement sensor 3, and the test of the two displacement sensors 3 is calculated. As a result, the calibration of the electric trigger soft probe 100 can be completed. Compared with the prior art, the test position in the present invention can reflect the rotation of the pushing part 21, and the two test positions are respectively arranged on both sides of the probe 101 to maximize the elimination of the error caused by the rotation of the pushing part 21 , which maximizes the elimination of the influence of the Abbe error on the calibration results, making the calibration results more accurate.

As a preferred embodiment, the fixing assembly 1 in the electric trigger soft probe calibration device in this embodiment includes a locking part 11 and a rotating part 12, and the locking part 11 is connected to the electric trigger soft probe 100, the rotating part 12 is connected to the locking part 11, and is used to drive the locking part 11 to drive the electric trigger soft probe 100 to rotate, the rotation axis of the rotating part 12 and the probe 101 The axes coincide. The locking part 11 is used to fix the electric trigger soft probe 100 , and the rotating part 12 is used to adjust the pose of the electric trigger soft probe 100 for comprehensive detection. In this embodiment, the locking part 11 is a knife lock seat, and the rotating part 12 is an R-axis rotating platform. In practice, other parts that can realize the above functions can also be used instead.

Further, the fixing assembly 1 in this embodiment further includes two magnetic watch bases 13 , and the two magnetic watch bases 13 are respectively connected to the two displacement sensors 3 . Magnetic table base 13, also known as universal table base, is the most used in the machine manufacturing industry and is widely used in various machine tools. It is also one of the indispensable testing tools and is also used in various scientific researches. According to the different types of the displacement sensor 3, other parts can also be used to fix the displacement sensor 3.

The fixed assembly 1 in this embodiment also includes a workbench 14, and the test simulation assembly 2, the rotating part 12 and the magnetic table base 13 are all connected to the workbench 14 to carry other parts role.

As a preferred embodiment, the test simulation component 2 in this embodiment includes an inclined block micrometer, the inclined block of the inclined block micrometer is the pushing part 21, and the inclined block type micrometer The inclined surface of the inclined block in the micrometer abuts against the measuring ball 102, and the two test positions are located on the inclined surface of the inclined block in the inclined block micrometer. The inclined block micrometer can simulate a small movement, that is, when its handle is rotated, the inclined block in the inclined block micrometer will move along the x-axis direction in Figure 1, because the surface in contact with the measuring ball 102 is inclined , so that the measuring ball 102 can move along the y-axis direction in FIG. 1 , and the large displacement of the slanting block along the y-axis direction can be converted into a small displacement along the x-axis direction through the inclination ratio of the surface of the slanting block to realize precise control.

The test position is located on the surface of the inclined block in contact with the measuring ball 102, two tiny areas on both sides of the probe 101 that can be regarded as points, which move together with the pushing part 21, when the pushing part 21 rotates slightly , the displacement of the two test positions will reflect the rotation of the pushing part 21 and the Abbe error with the probe 101 . In practice, the test position can also be other positions on the pushing part 21 , it only needs to be able to move together with the pushing part 21 and be able to be detected by the displacement sensor 3 .

As a preferred embodiment, the connecting line of the two test positions in this embodiment is perpendicular to the extension direction of the probe 101 , and the distances from the two test positions to the probe 101 are the same. Because the oblique block micrometer is selected as the workpiece for simulating movement in this embodiment, it mainly rotates in the yoz plane in Fig. 1, so adopting the above-mentioned design method can facilitate subsequent calculations, and in the calculation process of eliminating errors Easier. In practice, the specific setting positions of the two test positions can be adjusted according to the direction of the deflection error of the pushing part 21 .

As a preferred embodiment, the displacement sensor 3 in this embodiment is a contact sensor, the detecting end of the displacement sensor 3 abuts against the pushing part 21, and when the pushing part 21 pushes the measuring ball 102, the The moving direction is perpendicular to the extending direction of the probe 101 , and the detecting direction of the displacement sensor 3 is the same as the moving direction when the pushing part 21 pushes the measuring ball 102 . Likewise, the detection direction of the displacement sensor 3 in this embodiment can also facilitate subsequent calculations.

As shown in Fig. 2, the present invention also provides an electric trigger type soft probe calibration method, which uses the electric trigger type soft probe calibration device in the above embodiment, including:

S201. Use the pushing part 21 to push the measuring ball 102, obtain the displacement of the two test positions on the pushing part 21, and reset the pushing part 21;

S202, repeating the step S201 multiple times to obtain a set of displacements;

S203, adjusting the pose of the electric trigger type soft probe 100, repeating the step S202 to obtain multiple sets of displacements;

S204. Obtain calibration parameters according to multiple sets of displacements;

S205. Calibrate the electric trigger type soft probe 100 according to the calibration parameters.

The technical effects achieved by this method can be referred to the above embodiments, and will not be described too much here.

As shown in FIG. 3 , as a preferred embodiment, in steps S201 to S203 in this embodiment, the center of the measuring ball 102 is used as the calibration reference origin, the extension direction of the probe 101 is the x-axis, and the displacement sensor 3 The detection direction is the y-axis to establish a coordinate system, the center of the measuring ball 102, that is, the coordinates of the calibration reference origin is O _p (O _px , O _py , O _pz ), the radius of the measuring ball 102 is r _p , and the measuring ball The coordinates of the contact point between 102 and the inclined block micrometer are:

In the formula, O _Tx , O _Ty , and O _Tz are the coordinates on the x, y, and z axes of the contact point between the measuring ball 102 and the inclined block micrometer, respectively.

Taking the measurement points of the two displacement sensors 3 as the starting point of the range, the coordinates of the contact points between the displacement sensors 3 and the inclined block are respectively:

In the formula, A _Sx , A _Sy , and A _Sz are the coordinates on the x, y, and z axes of the contact point between a displacement sensor 3 and the inclined block, and Δz is the distance between the measurement point of the displacement sensor 3 and the center of the measuring ball 102 along the z axis. Axis distance;

In the formula, B _Sx , B _Sy , and B _Sz are the coordinates on the x, y, and z axes of the contact point between the other displacement sensor 3 and the inclined block;

By adjusting the differential screw of the inclined block micrometer, the inclined block moves along the x-axis direction, and at the same time, the inclined block generates an offset Δy in the y-axis direction, and at the same time, the inclined block also produces a movement around the x-axis The Abbe error is caused by the rotation, which is by an angle α. At this moment, the readings of the two displacement sensors 3 are the expected displacement of the test position, which can be expressed as:

分别为两个位移传感器3的读数，具体为当R-轴旋转平台的鼓轮读数为j时，第i次重复执行步骤S202时的读数，Δztanα为测试位与斜块之间与阿贝臂长度相关的差值。In the formula

are the readings of the two displacement sensors 3, specifically, when the reading of the drum of the R-axis rotary platform is j, the reading when step S202 is repeated for the ith time, Δztanα is the distance between the test position and the inclined block and the Abbe arm length-dependent difference.

Specifically, in step S201 and step S202, the inclined block micrometer needs to be reset after each test, and the next test is ready until n repetitions are completed.

In step S203, the specific means of adjusting the pose is to rotate the electric trigger soft probe 100 along the axis of the probe 101, that is, operate the R-axis rotating platform to rotate the electric trigger soft probe 100 until the When the electric trigger soft measuring head 100 reaches the set position, record the reading of the drum wheel of the R-axis rotating platform at the set position as j, and then start to execute step S202, and continue to adjust the electric trigger soft measuring probe 100 after the execution is completed. Head 100 to the next set position. This step can be completed after the electric trigger soft probe 100 rotates 360°, where j can be a plurality of discrete points within 360°, and the total number thereof is m.

Further, in a preferred embodiment, the calibration parameters obtained in step S204 include pre-travel amount μ _j , trigger stability parameter δ _j and overall stability parameter δ, specifically expressed as:

Wherein the pre-travel amount μ _j represents the mean value of the bias vector of the measuring ball 102 under the same test angle j, the trigger stability parameter δ _j represents the stability ability of the electric trigger type soft probe 100 under the trigger angle j, and the overall stability parameter δ Indicates the overall problem capability of the electric trigger soft probe 100 .

After obtaining these three parameters, step S205 can be executed to calibrate the electric trigger type soft probe 100 . The specific calibration method is the prior art, and will not be described too much in the present invention. It is worth noting that the above steps obtain the calibration parameters through the readings of the two displacement sensors 3, and the readings of the two displacement sensors 3 include the information of the Abbe error, and the combination of the readings of the two displacement sensors 3 can maximize Eliminate the influence of Abbe error on the measurement data, so that the final calibration parameters are the most accurate.

In a preferred embodiment, before step S201 is performed, a test is first triggered on the entire model of the electric trigger type soft probe calibration device to detect whether it can operate normally.

A set of specific experimental data obtained by this method is given below:

When j=0°, the readings of the two displacement sensors 3 when n=6:

When j=120°, the readings of two displacement sensors 3 when n=6:

When j=240°, the readings of two displacement sensors 3 when n=6:

Calibration parameters obtained from the above data:

The present invention provides an electric trigger type soft probe calibration device and calibration method, which fixes the electric trigger type soft probe 100 to be measured through the fixing component 1, and uses the test simulation component 2 to test the electric trigger type soft probe 100 , which simulates the movement of the object to be measured through the pusher 21. There are two test positions moving with it on the pusher 21. The displacement of the two test positions is detected by the displacement sensor 3, and the test of the two displacement sensors 3 is calculated. As a result, the calibration of the electric trigger soft probe 100 can be completed. Compared with the prior art, the test position in the present invention can reflect the rotation of the pushing part 21, and the two test positions are respectively arranged on both sides of the probe 101 to maximize the elimination of the error caused by the rotation of the pushing part 21 , which maximizes the elimination of the influence of the Abbe error on the calibration results, making the calibration results more accurate.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims (7)

1. An electric trigger type soft measuring head calibration device is used for calibrating an electric trigger type soft measuring head, the electric trigger type soft measuring head comprises a probe and a measuring ball, and the measuring ball is arranged at the tail end of the probe and is characterized by comprising:

the fixing component is connected with and fixes the electric triggering type soft measuring head;

the test simulation assembly is connected to the fixed assembly and comprises a movable pushing part, the pushing part is abutted against the test ball, two test positions are formed on the pushing part, and the two test positions are respectively located on two sides of the probe; the test simulation assembly comprises a sloping block micrometer, wherein a sloping block of the sloping block micrometer is the pushing part, the inclined surface of the sloping block in the sloping block micrometer is abutted against the measuring ball, two test positions are positioned on the inclined surface of the sloping block in the sloping block micrometer, the connecting line of the two test positions is perpendicular to the extending direction of the probe, and the distances from the two test positions to the probe are the same;

the two displacement sensors are connected to the fixing assembly and are respectively used for detecting the displacement of the two test positions, the displacement sensors are contact type sensors, the detection ends of the displacement sensors are abutted to the pushing portions, the moving direction of the pushing portions when pushing the ball to be tested is perpendicular to the extending direction of the probe, and the detecting direction of the displacement sensors is the same as the moving direction of the pushing portions when pushing the ball to be tested.

2. The device for calibrating an electrically triggered soft measuring head according to claim 1, wherein the fixing assembly comprises a locking part and a rotating part, the locking part is connected to the electrically triggered soft measuring head, the rotating part is connected to the locking part, the locking part is driven to rotate the electrically triggered soft measuring head, and the rotation axis of the rotating part is coincident with the axis of the probe.

3. The device of claim 2, wherein the fixing assembly further comprises two magnetic gauges, and the two magnetic gauges are respectively connected to the two displacement sensors.

4. An electrically triggered soft gauge head calibration apparatus as claimed in claim 3, wherein the fixed assembly further comprises a table to which the test simulation assembly, the rotatable portion and the magnetic gauge stand are all connected.

5. An electric triggering type soft measuring head calibrating method, which uses the electric triggering type soft measuring head calibrating device according to any one of claims 1-4, and is characterized by comprising the following steps:

step one, pushing the ball to be tested by using the pushing part, acquiring displacement amounts of two test positions on the pushing part, and resetting the pushing part;

step two, repeating the step one for a plurality of times to obtain a group of displacement;

step three, adjusting the pose of the electric triggering type soft measuring head, and repeating the step two to obtain a plurality of groups of displacement amounts;

step four, obtaining calibration parameters according to a plurality of groups of displacement quantities;

and fifthly, calibrating the electric triggering type soft measuring head according to the calibration parameters.

6. The method for calibrating an electrically triggered soft probe according to claim 5, wherein said adjusting the pose of the electrically triggered soft probe comprises:

and rotating the electric triggering type soft measuring head along the axis of the probe until the electric triggering type soft measuring head reaches a set position.

7. The method according to claim 6, wherein the displacement is a displacement of the test site along a movement direction of the pushing portion, and the calibration parameters include a pre-stroke amount, a trigger stability parameter, and an overall stability parameter.

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