JPH0771933A - Method and device for measuring shape - Google Patents

Abstract

PURPOSE:To enable measurements in a temperature-varying environment while reducing waiting time by performing compensating operations on a measured value of the position of a point for measurement, according to the relation between a compensation constant and the position coordinates of a reference point as measured at the time of measurement. CONSTITUTION:A proportional (compensation) constant A for a measured value of a shape and the position coordinates of a reference point is inputted to an information processor 10 by a compensation constant input means 26 and stored 27. The constant A shows the proportion of changes in position coordinates of the reference point to changes in amount of thermal deformation. A shape measuring means 12 measures the position of one measuring point disposed along the contour of a subject for measurement. That is, the means 12 fetches an output voltage from a measuring terminal 9 and puts the voltage in storage 13. Simultaneously, a reference-point position coordinates measuring means 23 detects the position coordinates of the predetermined reference point and puts it in storage 24. A compensating operation means 14 performs compensating operations on the measured value of the shape at the measuring point using the constant A and from the proportion of the measured value of the shape to the position coordinates of the reference point, thereby determining the corrected measured value of the shape and putting the value in storage 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the shape of an object to be measured under an environment where the temperature changes, and more particularly to a shape measuring method which can be used in an NC processing machine or the like.

[0002]

2. Description of the Related Art After machining a workpiece, shape measurement is performed in order to determine whether the machining shape of the workpiece is good or bad, and to obtain correction data used for subsequent correction processing. In this case, in order to eliminate the loss of time associated with attachment / detachment of the work, it is difficult to obtain the reproducibility of the work attachment state, and the machining accuracy of correction machining deteriorates.
Shape measurement is performed.

[0003]

When the shape of the work is measured on the processing machine as described above, the temperature of the work mounting portion rises due to the heat generated by the spindle motor rotating the work during the processing. After machining, when the spindle motor is stopped for measurement, the temperature of the work attachment part decreases. By the way, in the shape measurement, accurate measurement cannot be performed until a stable state with little temperature change is reached. However, the waiting time for the temperature to stabilize is long. For this reason,
Conventionally, in practice, the waiting time was reduced and the measurement accuracy was sacrificed to perform the measurement.

An object of the present invention is to provide a shape measuring method and apparatus capable of performing shape measurement in an environment where temperature changes, without sacrificing measurement accuracy and reducing waiting time.

[0005]

In order to achieve the above object, according to one aspect of the present invention, the positions of a plurality of measurement points arranged along the outline of an object to be measured are measured to determine the shape of the measurement points. In the shape measuring method to be measured, the correction constant based on the proportional relationship between the thermal deformation amount of the measured object and the position coordinate of the predetermined reference point is stored in advance, and the measurement of the position for each measured point of the measured object, When measuring the position of each measurement point, the position coordinates of the reference point are measured, and for each measurement value, the correction value is calculated and the correction calculation is performed based on the relationship between the correction constant and the position coordinate of the reference point at the time of measurement. A shape measuring method is provided which is characterized by being performed.

According to another aspect of the present invention, a measuring terminal for moving relative to a plurality of measuring points arranged along the outer shape of the object to be measured to detect a relative positional relationship with the measuring points. And an information processing device that obtains the shape of the object to be measured based on the output and the position of the measurement terminal at each measurement point, and moves the measurement terminal to the target position for each measurement point, and In a shape measuring device including a moving mechanism that relatively moves the information processing device, the information processing device captures the output of a measurement terminal for each of a plurality of measurement points arranged along the outer shape of the measured object, and measures the measured object. Shape measuring means for measuring the shape of the object, shape measured value storing means for storing the shape measured value, reference point position coordinate measuring means for measuring the position coordinates of the reference point at the time of measuring the position of each measuring point, and Position Reference point position coordinate storage means for storing the mark corresponding to the measurement point, correction constant input means for externally inputting a correction constant based on the proportional relationship between the thermal deformation amount of the object to be measured and the position coordinates of the reference point, Correction constant storage means for storing the input correction constant, correction calculation processing means for correcting the shape of the object to be measured, correction calculation value storage means for storing the calculated correction calculation value, and external measurement The correction calculation processing means includes an input / output means for receiving a command and outputting the correction calculation value stored in the correction calculation value storage means.
The measurement value of the position of each measurement point of the object to be measured is read from the measurement value storage means, the measurement position coordinate of each measurement point is read from the reference point position coordinate storage means, and further,
There is provided a shape measuring apparatus characterized in that a correction constant is read from a correction constant storage means, a correction value is obtained from a measurement position coordinate and a correction constant, and the measurement value is corrected by this correction value.

[0007]

According to the present invention, the amount of thermal deformation due to the temperature change of the shape of the object to be measured is calculated in advance based on the proportional relationship with the position coordinates of the reference point, and the correction constant is calculated in advance. , Correct the measured value. That is, for each measurement point, by knowing the position coordinates of the reference point at the time of measuring each position, the correction amount can be obtained from this correction constant, and the position measurement value can be corrected accordingly.

As described above, according to the present invention, since the amount of thermal deformation can be obtained and corrected, the waiting time can be reduced under the environment where the position coordinates change without sacrificing the measurement accuracy. The shape can be measured. That is, if the present invention is applied to a processing machine, it is possible to measure the shape of a work with high accuracy and high throughput.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of a state in which the first embodiment of the present invention is applied to a processing machine 1. FIG. 2 shows an example of the hardware system configuration of the information processing apparatus used in this embodiment. Further, FIG. 3 shows an outline of functions of the information processing apparatus in this embodiment.

In FIG. 1, an object to be measured 50 is used in this embodiment.
A measurement terminal 70 that is provided so as to be movable relative to each other and that detects the relative positional relationship of the object to be measured; a position measuring instrument 90 that measures the position of this measurement terminal 70 with a predetermined origin as a reference; Information processing device 10 for processing data
And a moving mechanism 80 for moving the measuring terminal 70 and the object to be measured (work). Measuring terminal 70 and position measuring device 9
0 (length measuring device 91) is mounted on the processing machine 1 as shown in FIG.

The shape measuring apparatus of this embodiment is provided in the processing machine 1. The processing machine 1 includes, as the moving mechanism 80, a stage 81 on which a workpiece, which is the object 50 to be measured, is placed, a support base 82 for movably supporting the stage 81, and a stage for moving the stage 81 by a necessary amount. Drive device 83
And a stage 84 for supporting the tool base 51 and the measurement terminal 70, a support base 85 for movably supporting the stage 84, and a stage drive device 86 for moving the stage 84 by a necessary amount. Also, the processing machine 1
Is an NC that controls the operation of the stage drive devices 83 and 86.
It is controlled by the controller 30 and the host computer 40 connected to the NC controller 30 and the information processing apparatus 10. The host computer 40 creates a control program for the NC controller 30 and various parameters necessary for machining, measurement, etc., outputs the parameters, and takes in the shape measurement information from the information processing device 10 to correct it. Create programs, parameters, etc.
Send to the NC controller 30.

The measuring terminal (measuring probe) 70 is composed of, for example, a differential transformer, and outputs a signal indicating a displacement amount of ± from the center position. In this embodiment, the measuring terminal 70 is of a contact type, but may be of a non-contact type.

As the position measuring device 90, an optical length measuring instrument 91 is used in this embodiment. That is, a mirror 94 is attached to the stage 81 and a mirror 96 is attached to the stage 84, and light rays are incident on the former via the mirrors 92 and 93 and on the latter via the mirror 95, respectively. The length measuring instrument 91 of this embodiment is provided with a mirror 94.
And 96 displacements are optically measured, and coordinate data based on a predetermined origin is output. In this embodiment, what is provided in the processing machine is shared, but it may be provided independently.

The information processing apparatus 10 is, as shown in FIG.
A central processing unit (CPU) 101, a first memory (ROM) 102 for storing a program of the CPU 101 and each fixed data, and a second memory (RAM) 103 for storing data read from the outside, a calculation result and the like. , A host computer interface 104 for connecting to an external host computer 40, a length measuring interface 105 for connecting to a length measuring device 91, and a measuring terminal 7.
A / D converter 107 for converting the output signal from 0 into a digital signal. In this embodiment, the input device, the display device, etc. are provided in the host computer 40. Of course, in the information processing device 10,
The input device and the display device may be connected.

The information processing apparatus 10 executes various functions shown in FIG. 3 by the CPU 101 and the first and second memories 102 and 103.

That is, the information processing apparatus 10 receives an external communication means 11 for exchanging data with the host computer 40, and a measurement command sent from the host computer 40 via the external communication means 11 for measurement. A shape measuring means 12 for taking the output signal from the terminal 70 to measure the shape of the object to be measured, a shape measured value storage means 13 for storing the measured value at each measuring point, and a reference point for receiving the above measurement command. Reference point position coordinate measuring means 23 for measuring the position coordinates of the reference point, reference point position coordinate storing means 24 for storing the reference point position coordinates corresponding to the measurement points, and correction calculation processing for performing calculation for correcting the temperature change of the shape measurement value. Means 14 and a correction calculation value storage means 15 for storing the corrected measurement value;
It has a correction constant input means 26 for externally inputting a correction constant used in the correction calculation, and a correction constant storage means 27 for storing the input correction constant.

The reference point position coordinate measuring means 23 is composed of a length measuring instrument 25 in this embodiment. And in FIG.
As shown in FIG. 10, a reflection part 52 showing a reference point on a work attachment part 52 for attaching an object to be measured (workpiece) 50.
The position of the reference point is measured by providing a, irradiating the measuring light from the length measuring device 21 to the reflecting portion 52a, and receiving the reflected light. The reflecting portion 52a may be provided on the surface of the work attaching portion 52 as shown in FIG. 9, or as shown in FIG.
It may be provided at the tip of the passage for measuring light provided inside the work attachment portion 52.

The shape measuring means 12 takes in the output of the measuring terminal 70 for each of a plurality of measuring points arranged along the outer shape of the object 50 to be measured, and measures the shape of the object 50 to be measured. For each measurement point, the relative position between each measurement point and the measurement terminal 70 is detected. The position of the measuring terminal 70 can be known from the coordinates of the target position of the movement command for the moving mechanism 80 that moves the measuring terminal 70. The host computer 40 sends the target position to the NC controller 30. The information processing device 10 can obtain the position of each measurement point from this and the output of the measurement terminal 70 by receiving the information of the target position from the host computer 40. That is, the shape measuring unit 12 measures the position of each measurement point to measure the shape of the measured object on which they are arranged.

The shape measurement value storage means 13, the reference point position coordinate storage means 24, and the correction calculation value storage means 15 are the second
The memory 103 is provided with each storage area.

The correction constant input means 26 is connected to an input device such as a keyboard, a keypad including a numeric keypad, a digital switch, or the like. In this embodiment, the keypad 2
0 is connected. The keypad 20 has a ten-key input unit 20a and a display unit 20b for displaying an input value, a message from the information processing device, and the like. An instruction as to whether or not to input the correction constant and the correction constant may be transferred and input from the host computer 40 via the external communication unit 11.

The input constants are stored in the correction constant storage means 27.
Stored in. The correction constant storage means 27 is, for example,
It is composed of registers. Note that this correction constant may be set to a different value depending on the material of the work. In this case, since it is complicated to reset the material each time the material of the work changes, a plurality of types of correction constants may be set in advance and the value to be applied may be selected from them. At this time, the correction constant input means 26 is provided with keys and functions for performing such selection operation. Further, the correction constant storage means 27 may be configured by providing a storage area in the second memory 103 described above.

When the correction constants are input from the host computer 40, various correction constants are stored in the host computer, and the host computer 40
In, the required correction constant may be selected and the corresponding correction constant may be transferred to the information processing device 10.

Next, the measurement operation of this embodiment will be described.

FIG. 4 shows an outline of the procedure of the measurement operation. This procedure is executed by the host computer 40 and the information processing device 10 that operates accordingly. In this embodiment, the theoretical shape of the object to be measured is given in advance, and the shape error is measured by the measuring terminal 70 to measure the shape of the object to be measured. Of course, the shape can be measured without giving the theoretical shape. In this case, from the output value of the length measuring instrument 91 and the output of the measuring terminal 70,
The shape of the measured object is measured by obtaining the position coordinates of each measurement point of the measured object.

Prior to the measurement, the information processing apparatus 10 receives an input of a proportional constant A (hereinafter, simply referred to as a correction constant) between the shape measurement value and the position coordinates of the reference point in the correction constant input means 26. First, it is determined whether a correction constant needs to be input (step 901). This is done by the correction constant input means 26 determining when a user presses a pre-defined key (s) for each input / non-input. Alternatively, a dedicated key may be provided and the determination may be made based on the key operation.

When it is necessary to input the correction constant, the user's key input is accepted and stored in the correction constant storage means 27 (step 902). This is performed by the user, for example, by keying in a correction constant previously obtained for the object to be measured. If you do not need to enter the correction constant, skip this step.

The proportionality constant A indicates, for example, as shown in FIG. 8, a proportional relationship between a change in the position coordinates of the reference point and a change in the thermal deformation amount.

Next, the host computer 40 instructs the NC controller 30 to move the measuring terminal 70 to the measuring point P1 (step 903). The movement to the measurement point P1 is accurately performed by measuring the relative movement position of the measurement terminal and the measured object by the length measuring instrument 91.

Next, a measurement command is output to the information processing device. In the information processing device 10, the external communication means 1
When this measurement command is received via 1, the shape measuring means 12 performs the first shape measurement for the point P1 (hereinafter, shape measurement is strictly speaking position measurement). That is, the output value M1 is taken in from the measuring terminal 70.
Further, the reference point position coordinate measuring means 23 detects the position coordinate Z1 at that time. Then, these are stored by the shape measurement value storage means 13 and the reference point position coordinate storage means 24, respectively (step 904).

Here, the measurement of the shape error by the measuring terminal 70 will be described. Here, the measurement principle when the differential transformer type measurement terminal is used will be described.

FIG. 5A shows that when the measuring terminal 70 is moved to the theoretical position, the shape of the DUT 50 is the theoretical shape, that is, the DUT 50 and the measuring terminal 70 are in contact with each other at the theoretical position. It shows the state of being done. At this time, the measuring terminal 70
The measurement terminal 70 is adjusted in advance so that the output voltage of the output signal becomes zero.

FIG. 5B shows that when the measuring terminal 70 is moved to the theoretical position, the object 50 to be measured has a shape error 32 with respect to the theoretical shape, that is, the object 50 to be measured and the measuring terminal 70 are The figure shows a state where the shape is in contact with the theoretical position at a position with a shape error 32.

On the other hand, since the relationship between the shape error and the output voltage of the measuring terminal is known in advance as shown in FIG. 6, the shape error e can be obtained by measuring the output voltage of the measuring terminal.

At this time, the positional accuracy of the work and the measuring terminal is guaranteed by the length measuring instrument 91 used for position control of each stage to which the work and the measuring terminal are attached.

In this example, the object to be measured 50 mounted on the stage 81 of the processing machine 1 and the measuring terminal 70 mounted on the stage 84 are moved in the measuring procedure of FIG. The position of the measurement point is the object to be measured 5
Assuming that 0 is formed according to the theoretical value, the measurement terminal 70
To the position where the output voltage of is zero. The output voltage of the measurement terminal 70 obtained at the position of each measurement point is taken in by the shape measuring means 12. Next, the shape is measured and the reference point position coordinates are measured by moving to the measurement point Pi, and the resulting shape measurement value Mi and reference point position coordinates Zi are stored (steps 905 and 906). This is performed for the number N of measurement points (step 907).

Next, the correction calculation processing means 14 uses the correction constant A input in advance from the proportional relationship between the shape measurement value and the reference point position coordinates to measure the shape of the measurement point Pi as shown in the following equation. A correction shape measurement value Mi <h>, which is a corrected measurement value, is calculated and stored in the correction calculation value storage means 15 (step 808).

[0038]

## EQU1 ## Mi <h> = Mi-A * (Zi-Z1) That is, P1 point is measured first, P2 point is then measured, and then P3 point and P4 point are measured. , Finally P
Measure N points. Then, the shape error is calculated based on the measurement principle. Table 1 shows an example of the measurement results.

[0039]

[Table 1]

From Table 1, it can be seen that the measurement temperature changes with the number of times of measurement, and the thermal deformation amount changes accordingly.

In each of the above embodiments, the information processing device and the NC controller 30 are configured by using independent hardware resources, but the present invention is not limited to this. For example, the configuration shown in FIGS. 10 and 11 can be adopted. Here, the hardware system shown in FIGS. 11 and 12 will be described focusing on the differences from the systems shown in FIGS. 1 and 2.

The processing machine 1 shown in FIG.
0 and the NC controller 30 are configured by a control computer 100 which is a common hardware resource. Therefore, the information processing device 10 and the NC controller 30 are each realized as a function of the control computer 100.

The hardware system shown in FIG. 12 is C
D / A converter 10 that converts a control signal from the PU 101 into an analog signal and outputs the analog signal to the stage driving devices 83 and 86
6 is further provided, and the other configuration is configured with the same hardware resources as the hardware system shown in FIG. Also,
The information processing device 10 and the NC controller 30 in this embodiment are functionally the same as those shown in FIG. Therefore, in this example, the same reference numerals are given.
For those functions, refer to the explanation already given.

[0044]

According to the present invention, since the amount of thermal deformation can be obtained and corrected, the waiting time can be reduced and the shape measurement can be performed under the environment where the temperature changes without sacrificing the measurement accuracy. Can be done. That is, if the present invention is applied to a processing machine, it is possible to measure the shape of a work with high accuracy and high throughput.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a configuration of a processing machine to which an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a hardware system configuration of an information processing device used in an embodiment of the present invention.

FIG. 3 is a block diagram functionally showing the configuration of an information processing apparatus used in an embodiment of the present invention.

FIG. 4 is a flowchart showing a measurement procedure according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a measuring principle of a measuring terminal used in the embodiment of the present invention.

FIG. 6 is a graph showing an example of output characteristics of the measurement terminal.

FIG. 7 is an explanatory diagram showing a measurement order for each measurement point of the measured object.

FIG. 8 is a graph showing an example of the relationship between the passage of measurement time and the positional coordinates of a reference point and changes in the amount of thermal deformation.

FIG. 9 is an explanatory diagram showing an example of a length measuring device that constitutes a reference point used in the embodiment of the present invention.

FIG. 10 is an explanatory diagram showing another example of the length measuring device that constitutes the reference point used in the embodiment of the present invention.

FIG. 11 is a block diagram showing another example of the configuration of a processing machine to which the embodiment of the present invention is applied.

FIG. 12 is a block diagram showing another example of the hardware system configuration of the information processing apparatus used in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing machine, 10 ... Information processing apparatus, 11 ... External communication means, 12 ... Shape measuring apparatus, 13 ... Shape measured value storage means,
14 ... Correction calculation processing means, 15 ... Correction calculation value storage means,
23 ... Reference point position coordinate measuring means, 24 ... Reference point position coordinate storing means, 25 ... Length measuring device, 26 ... Correction constant input means, 2
7 ... Correction constant storage means, 20 ... Keypad, 20a ... Numeric keypad input section, 20b ... Display section, 30 ... NC controller, 40 ... Host computer, 50 ... Object to be measured (work), 51 ... Tool stand, 52 ... Work Attachment part, 70 ... Measuring terminal.

Claims (2)

[Claims] 1. A shape measuring method for measuring a shape of a measurement point by measuring positions of a plurality of measurement points arranged along an outer shape of the measurement object, wherein a thermal deformation amount of the measurement object and a predetermined reference. A correction constant based on the proportional relationship with the position coordinate of the point is stored in advance, and the position of each measured point of the DUT is measured and the position coordinate of the reference point is measured when measuring the position of each measured point. A shape measuring method characterized in that, for each measurement value, a correction value is obtained and correction calculation is performed based on the relationship between the correction constant and the position coordinates of the reference point at the time of measurement. 2. A measuring terminal that moves relative to a plurality of measuring points arranged along the outer shape of an object to be measured to detect a relative positional relationship with the measuring point, and a measuring terminal at each measuring point. An information processing apparatus that determines the shape of the object to be measured based on the output and the position thereof, and a moving mechanism that moves the measurement terminal to a target position for each measurement point and moves the measurement terminal relative to each measurement point In the shape measuring device, the information processing device includes a shape measuring means for measuring the shape of the object to be measured by capturing the output of the measuring terminal for each of the plurality of measuring points arranged along the outer shape of the object to be measured. , Shape measurement value storage means for storing the shape measurement value, reference point position coordinate measurement means for measuring the position coordinates of the reference point at the time of measuring the position of each measurement point, and the measured position coordinates are stored for each measurement point. Ginseng Point position coordinate storage means, correction constant input means for externally inputting a correction constant based on the proportional relationship between the thermal deformation amount of the object to be measured and the position coordinates of the reference point, and correction for storing the input correction constant Constant storage means, correction calculation processing means for performing correction calculation of the shape of the object to be measured, correction calculation value storage means for storing the calculated correction calculation value, reception of a measurement command from the outside, correction calculation value storage means And an input / output unit for outputting the correction calculation value stored in the correction calculation processing unit. The correction calculation processing unit reads out the measurement value of the position of each measurement point of the measured object from the shape measurement value storage unit and , The measured position coordinate is read from the reference point position coordinate storage means, the correction constant is read from the correction constant storage means, the correction value is obtained from the measured position coordinate and the correction constant, and the measured value is calculated using this correction value. A shape measuring device characterized by performing correction of.