TWI600879B - Shape measuring device, processing device and shape measuring method - Google Patents

Description

Shape measuring device, processing device and shape measuring method

The present invention relates to a shape measuring device, a processing device, and a shape measuring method.

There is known a straightness measurement method in which the surface shape of the object to be measured is obtained by a three-point method using three displacement meters, and the straightness is measured (for example, refer to Patent Document 1).

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2003-254747

In the straightness measurement method, for example, when foreign matter such as garbage or oil or scratches are present on the surface of the object to be measured, the measured value measured by the displacement meter may fluctuate greatly, and it is difficult to obtain the measurement object with high precision. The surface shape.

The present invention has been made in view of the above, and an object thereof is to provide a The shape measuring device can measure the surface shape of the object to be measured with high precision by reducing the influence of foreign matter or the like existing on the surface.

According to one aspect of the present invention, a shape measuring apparatus scans an object to be measured by a detector in which three displacement meters are arranged in a row, and measures a surface shape of the object to be measured, and the shape measuring device includes: The gap calculating means obtains the gap data by the difference between the measured value measured by the displacement meter located in the middle of the three displacement meters and the measured value measured by the other displacement meter; and the interpolation means obtains the average value of the gap data and Standard deviation, and the interpolation process is repeatedly performed until the rate of change of the standard deviation is equal to or less than a predetermined value, and the interpolation process performs interpolation on a value outside the range set by the standard deviation in the gap data by the average value; And the shape calculation means calculates the surface shape of the object to be measured based on the gap data on which the interpolation process has been performed.

According to the embodiment of the present invention, it is possible to provide a shape measuring device capable of measuring the surface shape of the object to be measured with high precision by reducing the influence of foreign matter or the like existing on the surface.

12‧‧‧ objects (measurement objects)

20‧‧‧Control device

23‧‧‧Gap data calculation department (gap calculation mechanism)

25‧‧‧Interpolation Processing Department (Interpolation Mechanism)

27‧‧‧Shape calculation unit (shape calculation mechanism)

30‧‧‧Sensing head (detector)

31a‧‧‧1st displacement sensor (displacement meter)

31b‧‧‧2nd displacement sensor (displacement meter)

31c‧‧‧3rd displacement sensor (displacement meter)

40‧‧‧Display device (display mechanism)

100‧‧‧Shape measuring device

200‧‧‧Processing device

Fig. 1 is a view showing an example of a processing apparatus in an embodiment.

Fig. 2 is a view showing an example of the configuration of the shape measuring device in the embodiment.

Fig. 3 is a view showing an example of the structure of the sensor head in the embodiment.

Fig. 4 is a view for explaining shape measurement in the embodiment.

Fig. 5 is a view showing an example of the flow of the shape measuring process in the embodiment.

Fig. 6 is a diagram illustrating an example of sensor data in the embodiment.

Fig. 7 is a diagram showing an example of the gap data in the embodiment.

Fig. 8 is a view showing an example of the flow of the interpolation processing in the embodiment.

Fig. 9 is a view showing an example of the gap data before the interpolation processing in the embodiment.

Fig. 10 is a view for explaining interpolation processing of the gap data in the embodiment.

Fig. 11 is a view showing an example of the gap data after the interpolation processing is performed once in the embodiment.

Fig. 12 is a view showing an example of the gap data after the interpolation processing is repeatedly performed in the embodiment.

Fig. 13 is a view for explaining interpolation processing of the gap data in the embodiment.

Fig. 14 is a view showing an example of the gap data after the interpolation processing is performed in the embodiment.

Fig. 15 is a view showing an example of measurement results of the surface shape in the embodiment.

Fig. 16 is a view showing an example of measurement results of the surface shape in a state where no foreign matter is present on the surface of the object.

Fig. 17 is a diagram showing an example of measurement results of the surface shape in a state where the interpolation processing is not performed.

Hereinafter, embodiments will be described with reference to the drawings. In the respective drawings, the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

(Structure of processing device)

Fig. 1 is a view showing an example of a configuration of a processing apparatus 200 on which a shape measuring apparatus according to the present embodiment is mounted.

As shown in Fig. 1, the processing apparatus 200 includes a movable table 10, a table guiding mechanism 11, a grinding head 15, a grinding wheel 16, a guide rail 18, a control device 20, and a display device 40. In addition, in the following drawings, the X direction is the moving direction of the movable table 10, the Y direction is the moving direction of the grinding head 15 orthogonal to the X direction, and the Z direction is the height direction orthogonal to the X direction and the Y direction. .

The movable table 10 is provided so as to be movable in the X direction by the table guiding mechanism 11, and the object 12 to be processed and the object to be measured is placed. The table guiding mechanism 11 faces the movable table 10 toward the X side Moving to

A grinding wheel 16 is provided at a lower end portion of the grinding wheel head 15 so as to be movable in the X direction and to be lifted in the Z direction. The guide rail 18 moves the grinding head 15 in the X direction and the Z direction. The grinding wheel 16 has a cylindrical shape and is rotatably provided at a lower end portion of the grinding wheel head 15 such that its central axis is parallel to the Y direction. The grinding wheel 16 moves in the X direction and the Z direction together with the grinding wheel head 15, and rotates to grind the surface of the object 12.

The control device 20 controls the respective portions of the processing apparatus 200 by grinding the surface of the object 12 by controlling the positions of the movable table 10 and the grinding wheel head 15 and rotating the grinding wheel 16.

The display device 40 is an example of a display mechanism, and is, for example, a liquid crystal display or the like. The display device 40 is controlled by the control device 20 and displays, for example, processing conditions of the object 12 and the like.

(Structure of shape measuring device)

FIG. 2 is a view exemplifying a configuration of the shape measuring device 100 mounted on the processing device 200. As shown in FIG. 2, the shape measuring apparatus 100 includes a control device 20, a sensing head 30, and a display device 40.

As described above, the control device 20 controls the respective portions of the processing device 200 so as to grind the surface of the object 12, and is obtained by the measured values output from the displacement sensors 31a, 31b, and 31c of the sensing head 30. The surface shape of the object 12.

The control device 20 includes a sensor data acquisition unit 21, a gap data calculation unit 23, an interpolation processing unit 25, and a shape calculation unit 27. Control device 20 Including, for example, a CPU, a ROM, a RAM, etc., and the functions of the respective sections are realized by a CPU executing a control program stored in the ROM in cooperation with the RAM.

The sensor data acquisition unit 21 acquires sensor data from the displacement sensors 31a, 31b, and 31c provided in the sensor head 30. The gap data calculation unit 23 is an example of the gap calculation unit, and calculates the gap data by the sensor data acquired by the sensor data acquisition unit 21. The interpolation processing unit 25 is an example of an interpolation mechanism, and performs interpolation processing on the gap data calculated by the gap data calculation unit 23. The shape calculation unit 27 is an example of a shape calculation unit, and calculates the surface shape of the object 12 based on the gap data in which the interpolation processing unit 25 performs interpolation processing.

The sensor head 30 is an example of a detector, and includes a first displacement sensor 31a, a second displacement sensor 31b, and a third displacement sensor 31c, and is provided at a lower end of the grinding head 15 of the processing apparatus 200. Fig. 3 is a view showing an example of the structure of the sensing head 30 according to the embodiment.

As shown in FIG. 3, in the sensor head 30, the first displacement sensor 31a, the second displacement sensor 31b, and the third displacement sensor 31c are arranged in a line in the X direction.

The first displacement sensor 31a, the second displacement sensor 31b, and the third displacement sensor 31c are examples of the displacement meter, and are, for example, laser displacement meters. The first displacement sensor 31a, the second displacement sensor 31b, and the third displacement sensor 31c are disposed such that the measurement points are arranged at equal intervals on the surface of the object 12 in a line parallel to the X direction, and the objects are respectively aligned with each other. The distance between the measurement points on the surface of 12 was measured. When the object 12 is mounted on the movable table 10 and moved in the X direction, the sensing head 30 is opposed to the object 12 Moving, each of the displacement sensors 31a, 31b, and 31c scans the surface of the object 12 to output a measured value.

The display device 40 is controlled by the control device 20, and displays, for example, a measurement result of the surface shape obtained by the shape calculating unit 27, and the like.

Further, in the present embodiment, the shape measuring device 100 and the processing device 200 are configured to share the control device 20 and the display device 40. However, the control device and the display device may be provided in the shape measuring device 100 and the processing device 200, respectively. Further, the movable table 10 is configured to move in the X direction together with the object 12, but may be configured such that the sensor head 30 moves in the X direction with respect to the object 12.

(The basic principle of shape measurement)

Next, a method of obtaining the surface shape of the measuring object 12 by the shape measuring device 100 will be described. Fig. 4 is a view for explaining a method of measuring a surface shape.

As shown in FIG. 4, the displacement sensors 31a, 31b, and 31c are arranged in a row at intervals P in the X direction, and respectively perform distances from points a, b, and c on the surface of the object 12. Determination. If the distances between the displacement sensors 31a, 31b, and 31c obtained by the displacement sensors 31a, 31b, and 31c and the surface of the object 12 are respectively A, B, and C, then from Fig. 4 (A) The distance g (gap) between the point b in the Z direction and the line connecting the point a and the point c is shown by the following formula (1).

[Math 1] g = B -( A + C )/2...(1)

Next, as shown in FIG. 4(B), the second-order differential (d ² z/dx ² ) of the displacement z at the b-point of the surface of the object 12 is the curvature (b) of the b-point, and the a point and b are connected by using The inclination of the straight line of the point (dz _ab /dx) and the inclination of the straight line connecting the point b and the point c (dz _bc /dx) are shown by the following formula (2).

In the formula (2), the following formulas (3) and (4) are substituted, and as shown in the formula (5), it is understood that the distance (g) and the distance P between the sensors can be used by further using the formula (1). The second-order differential of the displacement z is also the curvature.

The distance P between the sensors is set in advance, whereby the gap g can be found based on the sensor data output from the displacement sensors 31a, 31b, 31c according to the formula (1), and the basis is (5) The obtained curvature is second-order integrated at the sensor interval P, and the displacement z at the point b can be obtained.

However, if foreign matter such as garbage or oil or scratches are present on the surface of the object 12, and the sensor data is largely changed by the influence of foreign matter or the like, it may be difficult to accurately determine the surface shape of the object 12. Therefore, the shape measuring apparatus 100 according to the present embodiment measures the surface shape of the object 12 by the shape measuring process to be described below.

(shape measurement processing)

Fig. 5 is a view showing an example of the flow of the shape measuring process in the embodiment.

In the shape measurement processing of the present embodiment, first, in step S101, the movable table 10 moves in the X direction together with the object 12 as the measurement target, and the displacement sensors 31a, 31b, 31c of the sensor head 30 are paired. The surface of the object 12 is scanned.

Next, in step S102, the sensor data acquisition unit 21 acquires sensor data from the displacement sensors 31a, 31b, and 31c. Figure 6 is true The sensor data in the configuration is illustrated. Each of the displacement sensors 31a, 31b, 31c outputs sensor data as a distance from a measurement point of the surface of the object 12. In the graph shown in Fig. 5, the data of the first displacement sensor 31a is indicated by a dashed line, the data of the second displacement sensor 31b is indicated by a solid line, and the third displacement sensor 31c is indicated by a broken line. data of.

In the case where foreign matter or the like is present on the surface of the object 12, as shown in Fig. 6, the sensor data in the presence of foreign matter or the like largely changes. In the example shown in Fig. 6, the displacement sensor 31a is in the vicinity of 150 mm, the displacement sensor 31b is in the vicinity of 250 mm, and the displacement sensor 31c is in the vicinity of 350 mm, and the sensor data is affected by foreign matter or the like. They become very large values. Further, since the displacement sensors 31a, 31b, and 31c are provided at intervals in the scanning direction, that is, in the X direction, even if the measurement results on the same surface are different, the position of data fluctuation caused by foreign matter or the like is different.

Returning to the flow of Fig. 5, the gap data calculating unit 23 calculates the gap data from the sensor data of the displacement sensors 31a, 31b, and 31c in accordance with the equation (1). Fig. 7 is an example of calculation of the gap data calculated from the sensor data shown in Fig. 6.

As described above, when foreign matter or the like is present on the surface of the object 12, the gap data greatly changes due to the influence of foreign matter or the like, and it is difficult to accurately obtain the surface shape of the object 12. Therefore, in the shape measurement processing of the present embodiment, the interpolation processing unit 25 performs interpolation processing on the gap data in step S104.

(interpolation processing)

Fig. 8 is a view showing an example of the flow of the interpolation processing in the embodiment.

In the interpolation processing, first, in step S201, the interpolation processing unit 25 calculates the average value and the standard deviation σ of the gap data. Next, in step S202, the interpolation processing unit 25 determines the presence or absence of the data in the presence or absence of the gap data (average value ±3σ).

If there is no data outside the range of (average value ±3σ) (step S202: NO), the process proceeds to step S203, and the interpolation processing unit 25 determines that there is no foreign matter on the surface of the object 12 and sets the foreign matter flag to "False". And end the interpolation process.

If there is any data outside the range of (average value ±3σ) (step S202: YES), the process proceeds to step S204, and the interpolation processing unit 25 determines that foreign matter is present on the surface of the object 12 and sets the foreign matter flag to "True". Next, in step S205, the interpolation processing unit 25 interpolates the data outside the range of the gap data (average value ±3σ) by the average value.

For example, there is data outside the range of (mean ± 3σ) in the gap data shown in Fig. 9. In this case, for example, as shown in FIG. 10(A), the interpolation processing unit 25 deletes the data larger than (average value +3σ) and deletes it by the average value as shown in FIG. 10(B). The part is interpolated. Similarly, the interpolation processing unit 25 deletes the data smaller than (average - 3σ), and interpolates the deleted portion with the average value. With this treatment, the influence of the foreign matter existing on the surface of the object 12 in the gap data is reduced.

Next, in step S206, the interpolation processing unit 25 calculates the average value and the standard deviation of the gap data again. Fig. 11 is a gap data obtained by interpolating data outside the range of the average value (mean ± 3σ) from the gap data shown in Fig. 9. As shown in Fig. 11, if there is data outside the range of (average ± 3σ), the interpolation processing unit 25 similarly interpolates the data outside the range of the average value (mean ± 3σ) by the step S207.

In step S208, the interpolation processing unit 25 performs the rate of change |(σ _n -σ _n-1 )/σ _n ×100|(%) of the calculated standard deviation σ _n and the previously calculated standard deviation σ _n-1 . Calculate and determine whether the rate of change of the standard deviation σ is less than 0.1%. The interpolation processing unit 25 repeatedly performs the processing of steps S206 and S207 until the rate of change of the standard deviation σ is, for example, less than 0.1%. By repeatedly performing the processes of steps S206 and S207, the influence of the foreign matter existing on the surface of the object 12 in the gap data is further reduced.

Fig. 12 is a step of repeatedly performing the processing of steps S206 and S207 until the rate of change of the standard deviation σ is less than 0.1%. As compared with the gap data before the interpolation processing shown in Fig. 9, it can be seen that the data variation due to the foreign matter existing on the surface of the object 12 in the gap data shown in Fig. 12 is greatly reduced. In addition, the target value of the rate of change of the standard deviation σ is not limited to 0.1%, and can be appropriately set depending on, for example, the required measurement accuracy.

Next, in step S209, the interpolation processing unit 25 linearly interpolates the data of the interpolation region including the data before and after the interpolation data in the gap data by using the average value of the data before and after the interpolation data. Using Figure 13 The processing of step S209 will be specifically described.

As shown in FIG. 13(A), the interpolation processing unit 25 sets the range of the interpolation data including the average value in the gap data and the data before and after the interpolation data (for example, 3 mm in front and rear) as the interpolation region. Further, the interpolation region is not limited to a range of 3 mm each including the front and rear of the interpolation data, and can be appropriately set by, for example, measurement conditions.

Next, the interpolation processing unit 25 calculates an average value of each of the data before and after the interpolation data in the interpolation region. In the example of Fig. 13(A), the average value of the data before the interpolation data (the left side of the interpolation data in Fig. 13) is a, and the average of the data after the interpolation data (the right side of the interpolation data in Fig. 13) is average. The value is b. As shown in FIG. 13(B), the interpolation processing unit 25 deletes the gap data in the interpolation region, and linearly interpolates the interpolation region by connecting the straight line of the average value a and the average value b.

Fig. 14 is a diagram illustrating the gap data shown in Fig. 12 to the gap data after linear interpolation of the interpolation region. In the gap data shown in Fig. 14, it is understood that the influence of foreign matter existing on the surface of the object 12 in the vicinity of 150 mm, around 250 mm, and around 350 mm of the X coordinate in the gap data of Fig. 12 is reduced.

Further, in the case where the influence of foreign matter or the like can be reduced in the gap data by the processing of steps S201 to S208, the interpolation region in step S209 may not be linearly interpolated.

The interpolation processing unit 25 performs the interpolation processing described above, and removes the influence of the foreign matter existing on the surface of the object 12 in the gap data, and returns to the shape measurement processing shown in FIG. 5, and proceeds to the step. S105.

In step S105, the shape calculation unit 27 calculates the surface shape of the object 12 based on the equation (5) by using the gap data of the interpolation processing by the interpolation processing unit 25. Further, the surface shape of the object 12 calculated by the shape calculating unit 27 is displayed on the display device 40.

Next, in step S106, the interpolation processing unit 25 determines whether or not the foreign matter flag is "True". When the foreign matter flag is "True" (step S106: YES), the foreign matter detection result such as "detecting foreign matter such as garbage in the vicinity of the forefront of 136 mm" is displayed on the display device 40 as a warning, for example, in step S107. When the foreign matter flag is "False" (step S106: NO), the processing is ended without displaying the foreign matter detection result.

The operator using the shape measuring device 100 recognizes that there is a foreign matter or the like from the warning displayed on the display device 40, and if the measurement is to be performed with higher accuracy, the measurement can be performed again after removing the foreign matter or the like.

Fig. 15 is a view showing the surface shape measurement result of the object 12 in which foreign matter or the like is present on the surface calculated by the gap data on which the interpolation processing has been performed, as shown in Fig. 14. Further, the surface shape measurement result of the object 12 in which foreign matter such as garbage is not present on the surface is shown in Fig. 16. Fig. 15 and Fig. 16 show the surface shape measurement results of the same portion of the same object 12, but differ in the presence or absence of foreign matter. In addition, the surface shape measurement result which is directly obtained by performing interpolation processing using the gap data which is affected by foreign matter or the like shown in FIG. 7 is shown in FIG.

As shown in Fig. 17, the results of the measurement are directly performed by performing interpolation processing on the surface shape of the object 12 in which foreign matter or the like is present on the surface, and the 16th The surface shape measurement result of the object 12 in which no foreign matter or the like is present as shown in the drawing is considerably different. As described above, it is understood that when the gap data is affected by foreign matter or the like existing on the surface of the object 12, the result is greatly different from the actual surface shape of the object 12.

On the other hand, in the surface shape measurement result in the present embodiment shown in Fig. 15, it is found that the surface shape measurement result of the object 12 when there is no foreign matter shown in Fig. 16 is obtained. As described above, according to the present embodiment, by performing the interpolation processing described above, the influence of the foreign matter in the gap data is reduced, and even when foreign matter or the like is present on the surface of the object 12, the same surface shape as when no foreign matter or the like is present can be obtained. Measurement results.

As described above, the shape measuring apparatus 100 according to the present embodiment can measure the surface shape with high precision even if the object 12 such as foreign matter or scratches such as garbage or oil is present on the surface.

Further, in the processing apparatus 200 equipped with the shape measuring apparatus 100 according to the present embodiment, after the surface of the object 12 is ground, the shape is mounted on the movable table 10 by the shape. The surface shape measurement result performed by the measuring apparatus 100 can perform correction processing or the like. Therefore, the object 12 can be processed with high efficiency and high precision.

In the above, the shape measuring device, the processing device, and the shape measuring method according to the embodiment have been described. However, the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the invention.

For example, the shape measuring device 100 can be mounted on a processing device, the plus The workpiece 12 is subjected to grinding or the like in a configuration different from that of the present embodiment.

Claims (5)

A shape measuring device that scans an object to be measured by a detector in which three displacement meters are arranged in a row, and measures a surface shape of the object to be measured, and the shape measuring device is characterized in that: a gap calculating mechanism is provided The gap data is obtained by the difference between the measured value measured by the displacement meter located in the middle of the three displacement meters and the measured value measured by another displacement meter; and the interpolation means determines the average value and the standard deviation of the gap data. And performing interpolation processing repeatedly until the rate of change of the standard deviation is equal to or less than a predetermined value, and the interpolation process performs interpolation on a value outside the range set by the standard deviation in the gap data by the average value; and a shape The calculation means calculates the surface shape of the object to be measured by the aforementioned gap data on which the interpolation process has been performed. The shape measuring device according to the first aspect of the invention, wherein the interpolation means includes, in the gap data in which the interpolation processing has been performed, a value of an interpolation region of data before and after interpolation data interpolated by the average value, The average value of each of the data before and after the interpolation data of the interpolation region is linearly interpolated. The shape measuring device according to claim 1 or 2, wherein the shape measuring device includes a display mechanism, and when the gap information includes a value other than the range, the display mechanism is displayed on the object to be measured Foreign matter is present on the surface. A processing apparatus comprising the shape measuring apparatus according to claim 1 or 2 of the patent application. A shape measuring method is characterized in that a measuring object is scanned by three detectors arranged in a row, and a surface shape of the measuring object is measured, and the shape measuring method is characterized by: a gap calculating step The gap data is obtained by the difference between the measured value measured by the displacement meter located in the middle of the displacement meter of the above 3 and the measured value measured by another displacement meter; and the interpolation step is performed to obtain the average value and the standard deviation of the gap data. And performing interpolation processing repeatedly until the rate of change of the standard deviation is equal to or less than a predetermined value, and the interpolation process performs interpolation on a value outside the range set by the standard deviation in the gap data by the average value; and a shape The calculating step calculates the surface shape of the object to be measured by the aforementioned gap data on which the interpolation process has been performed.