JP2010185804A - Shape measuring apparatus, shape measuring method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measuring apparatus capable of measuring a measuring object composed of a rotational body with high accuracy by a simple structure concerning measurement peculiar to the object, and to provide its measuring method, and a program. <P>SOLUTION: The shape measuring apparatus measures a displacement of a surface at each rotation angle of the measuring object 4 composed of the rotational body, while rotating the measuring object 4 around a predetermined axis of rotation. A controller 41 of the shape measuring apparatus preparatorily measures the displacement of the surface at each rotation angle of the measuring object 4 (S11). From a measured value representing a surface profile of the measuring object 4 acquired by the preparatory measurement and a design value of the measuring object 4 stored previously, the controller 41 calculates the amount of the deviation of the measured value from the design value (S12). The controller 41 adjusts the posture of the measuring object 4 on the basis of the calculated deviation amount (S13). While rotating the measuring object 4 after the posture adjustment around the rotation axis, the controller 41 measures the displacement of the surface at each rotation angle of the measuring object 4 regularly (S14). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a shape measuring apparatus such as a so-called roundness measuring device, a shape measuring method, and a shape measuring program for measuring displacement in synchronization with a rotation angle of a measured object that rotates relatively around a predetermined rotation axis. About.

  Conventionally, in measuring an object to be measured having an aspheric shape such as an aspheric lens, a method of measuring the surface of the object to be measured while moving a contact-type measurement probe along an X axis and a Y axis orthogonal to each other (Patent Documents 1 and 2), a method using an optical probe (Patent Documents 3 and 4), and the like are known.

  Of these, the method of moving the contact measurement probe along the X-axis and the Y-axis is difficult to obtain accurate measurement data as surface data when either one of the straightness accuracy is poor. However, there is a problem that the accuracy is insufficient to obtain measurement items such as coaxiality and rotational runout characteristic of the rotating body.

  Further, the method using an optical probe requires a laser light emitting device, and there is a problem that the device is large and expensive.

JP-A-7-120239 JP 2002-357415 A JP-A-4-340406 Japanese Patent Laid-Open No. 7-4929

  The present invention provides a shape measuring apparatus, a method, and a program capable of performing measurement peculiar to an object to be measured that is a rotating body with a simple configuration and high accuracy.

  The shape measuring apparatus according to the present invention is a shape measuring apparatus for measuring a displacement of a surface at each rotation angle of the object to be measured while rotating the object to be measured which is a rotating body around a predetermined rotation axis. Means for preliminarily measuring the displacement of the surface at each rotation angle of the measurement object, the measurement value indicating the surface shape of the measurement object obtained by the preliminary measurement, and the measurement object stored in advance Means for calculating a deviation amount of the measurement value from the design value with respect to the design value, means for adjusting the posture of the object to be measured based on the calculated deviation amount, and the measurement object after the posture adjustment. And a means for performing a control for actual measurement of the displacement of the surface at each rotation angle of the object to be measured while rotating the object about the rotation axis.

  The shape measuring method according to the present invention is the shape measuring method for measuring the displacement of the surface at each rotation angle of the measured object while rotating the measured object made of a rotating body around a predetermined rotation axis. Preliminarily measuring the displacement of the surface at each rotation angle of the measurement object, the measurement value indicating the surface shape of the measurement object obtained by the preliminary measurement, and the design value of the measurement object stored in advance Calculating a deviation amount of the measurement value with respect to the design value; adjusting a posture of the measurement object based on the calculated deviation amount; and And measuring the displacement of the surface at each rotation angle of the object to be measured while rotating around the center.

  The shape measurement program according to the present invention is a shape measurement program for measuring a displacement of a surface at each rotation angle of the measurement object while rotating the measurement object formed of a rotating body around a predetermined rotation axis. Preliminarily measuring the displacement of the surface at each rotation angle of the object to be measured in the computer, the measurement value indicating the surface shape of the object to be measured obtained by the preliminary measurement, and the object to be measured stored in advance Calculating a deviation amount of the measurement value from the design value with respect to the design value, adjusting a posture of the object to be measured based on the calculated deviation amount, and the measurement object after the posture adjustment. And measuring the displacement of the surface at each rotation angle of the object to be measured while rotating the object around the rotation axis.

  According to the present invention, it is possible to provide a shape measuring apparatus, a method thereof, and a program capable of performing measurement peculiar to a measured object made of a rotating body with a simple configuration and high accuracy.

It is an external appearance perspective view which shows schematic structure of the shape measuring apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the arithmetic processing unit main body 31 of the shape measuring apparatus which concerns on embodiment. It is a flowchart which shows operation | movement of the shape measuring apparatus which concerns on embodiment. It is a figure for demonstrating operation | movement of step S112. It is a figure which shows the pseudo | simulation measurement point Pi. It is a figure for demonstrating operation | movement of step S113. It is a figure which shows distribution of the pseudo | simulation measurement point Pi obtained after step S11 (step S114). It is a figure for demonstrating the least square method.

  Next, an embodiment according to the present invention will be described with reference to the drawings.

[Configuration of Shape Measuring Device According to Embodiment]
First, the configuration of the shape measuring apparatus according to the embodiment will be described with reference to FIG. FIG. 1 is an external perspective view of a shape measuring apparatus (roundness measuring apparatus) according to an embodiment.

  The shape measuring apparatus measures the displacement of the surface at each rotation angle of the measurement object 4 while rotating the measurement object 4 (for example, an aspheric lens) made of a rotating body around a predetermined rotation axis. As shown in FIG. 1, the shape measuring apparatus includes a measuring machine main body 1 and an arithmetic processing device 2 connected to the measuring machine main body 1 via a drive control device 1a.

  The measuring machine main body 1 includes a base 3, a table 5 provided on the base 3 for placing and rotating a hemispherical measurement object 4, and a measurement object 4 placed on the table 5. The displacement detection device 6 for detecting the displacement of the first and the operation unit 7 for operating these are provided.

  The table 5 rotates the measurement object 4 placed on the stage 11 by rotating the disk-like stage 11 with a rotation driving device 12 disposed below the disk-like stage 11. It is. On the side surface of the rotary drive device 12, adjustment knobs 13 are arranged at intervals of approximately 90 degrees in the circumferential direction. By operating these adjustment knobs 13, the stage 11 can be centered and leveled manually. That is, the stage 11 is configured to be adjustable in the X-axis, Y-axis, and Z-axis directions. Further, the stage 11 is configured such that centering and leveling are performed by a control unit 41 described later.

  The displacement detection device 6 is configured as follows. That is, a column 21 extending upward is erected on the base 3, and a slider 22 is mounted on the column 21 so as to be movable up and down. A stylus 23 is attached to the slider 22. The stylus 23 is configured to be drivable in the horizontal (X-axis, Y-axis) and vertical (Z-axis) directions, and a contactor 24 is provided at the tip thereof. The contact 24 is configured such that the tip thereof can contact the object to be measured. The column 21, the slider 22, and the stylus 23 constitute contactor driving means.

  The slider 22 and the stylus 23 are moved, and the contact 24 is scanned (traced) on the surface of the DUT 4 so that the surface height Z at each position in the X-axis direction is measured data (pseudo measurement point Pi). It has come to be obtained as.

  The arithmetic processing device 2 takes in the pseudo measurement point Pi obtained by the displacement detection device 6. The arithmetic processing device 2 includes an arithmetic processing device main body 31 that executes arithmetic processing, an operation unit 32, and a display screen 33. Further, the arithmetic processing device 2 is configured to be able to control the operation of the measuring machine main body 1 in the same manner as the operation unit 7.

  Next, the configuration of the arithmetic processing unit main body 31 will be described with reference to FIG. FIG. 2 is a block diagram showing a configuration of the arithmetic processing unit main body 31 according to the embodiment of the present invention.

  As shown in FIG. 2, the arithmetic processing unit main body 31 mainly includes a control unit (CPU: Central Processing Unit) 41, a RAM (Random Access Memory) 42, a ROM (Read Only Memory) 43, and an HDD (Hard Disk Drive). 44 and a display control unit 45. In the arithmetic processing unit main body 31, code information and position information input from the operation unit 32 are input to the control unit 41 via the I / F 46a. The control unit 41 executes various processes according to the macro program stored in the ROM 43 and the various programs stored in the RAM 42 from the HDD 44 via the I / F 46b.

  The control unit 41 controls the measuring machine main body 1 via the I / F 46c according to the measurement execution process. The HDD 44 is a recording medium that stores various control programs. The RAM 42 stores various programs and provides a work area for various processes. In addition, the control unit 41 displays measurement results and the like on the display screen 33 via the display control unit 45.

  The control unit 41 reads out various programs from the HDD 44 and executes the programs, thereby executing the operation shown in FIG. The control unit 41 performs control for preliminarily measuring the displacement of the surface at each rotation angle of the DUT 4. The control unit 41 calculates a deviation amount of the measured value with respect to the design value from the measured value indicating the surface shape of the measured object 4 obtained by the preliminary measurement and the design value of the measured object 4 stored in advance. The control unit 41 adjusts the posture of the DUT 4 based on the calculated deviation amount. The control unit 41 performs control for main measurement of the displacement of the surface at each rotation angle of the DUT 4 while rotating the DUT 4 after posture adjustment about the rotation axis.

[Operation of Shape Measuring Device According to Embodiment]
Next, the operation of the shape measuring apparatus according to the embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the shape measuring apparatus according to the embodiment.

  First, the control unit 41 preliminarily measures the displacement of the surface at each rotation angle of the DUT 4 (step S11).

  Here, step S11 will be described more specifically. In step S11, the control unit 41 moves the contactor 24 to the start position Ps in the X-axis direction (step S111). Next, as illustrated in FIG. 4, the control unit 41 acquires the pseudo measurement point Pi by scanning the contact 24 as the table 5 is rotated 360 ° around the Z-axis direction (step S <b> 112). . As shown in FIG. 5, the pseudo measurement point Pi is a point indicating a predetermined position of the contactor 24 when contacting the measurement object 4. A line segment connecting the plurality of pseudo measurement points Pi has a predetermined distance from the work surface S0. Subsequently, as shown in FIG. 6, the control unit 41 moves the contactor 24 by a predetermined distance L in the X-axis direction (step S113). Next, the control unit 41 determines whether or not the contactor 24 is located at the end position Pe in the X-axis direction (step S114). Here, when the control unit 41 determines that the contactor 24 is not located at the end position Pe in the X-axis direction (step S114, N), the process from step S112 is executed again. On the other hand, when the control unit 41 determines that the contactor 24 is located at the end position Pe in the X-axis direction (step S114, Y), the process proceeds to step S12.

  In step S <b> 12, the control unit 41 calculates a deviation amount of the measured value with respect to the design value from the measured value indicating the surface shape of the measured object 4 acquired by the preliminary measurement and the design value of the measured object 4 stored in advance. Calculate (step S12). Specifically, the control unit 41 uses a least square method (best fit) to design the pseudo measurement point Pi (measured value) and the design surface f (a, x) (f (a, x)) = 0) (design value) and the arrangement state (deviation amount) of the DUT 4 is estimated by the comparison. Here, the arrangement state of the DUT 4 includes the direction in which the central axis of the DUT 4 is facing.

  Here, for example, when the center in the Z-axis direction of the DUT 4 is aligned with the center of the rotation axis (Z-axis) of the table 5, the pseudo measurement point Pi used in step S12 is as shown in FIG. In the XY plane, a plurality of concentric circles are distributed along the measurement path.

  Next, the control part 41 adjusts the attitude | position of the to-be-measured object 4 based on the calculated deviation | shift amount (step S13). Specifically, the control unit 41 adjusts the stage 11 so that the center axis of the DUT 4 coincides with the rotation axis of the stage 11 based on the estimated arrangement state of the DUT 4. The posture of the DUT 4 is adjusted.

  Subsequently, the control unit 41 performs the main measurement of the displacement of the surface at each rotation angle of the DUT 4 while rotating the DUT 4 after the posture adjustment about the rotation axis (Step S14).

  Here, step S14 will be described more specifically. In step S14, the control unit 41 moves the contactor 24 to the start position Ps' in the X-axis direction (step S141). Next, as the table 5 is rotated 360 ° about the Z-axis direction, the control unit 41 scans the contact 24 to obtain a pseudo measurement point Pi ′ (step S142). Subsequently, the control unit 41 moves the contactor 24 by a predetermined distance L in the X-axis direction (step S143). Next, the control unit 41 determines whether or not the contactor 24 is located at the end position Pe ′ in the X-axis direction (step S144). Here, when the control unit 41 determines that the contact 24 is not located at the end position Pe ′ in the X-axis direction (step S144, N), the process from step S142 is executed again. On the other hand, when the control unit 41 determines that the contactor 24 is located at the end position Pe ′ in the X-axis direction (step S144, Y), the process ends.

  Next, the process of the least square method (step S105) will be described with reference to FIG. As shown in FIG. 8, in the least square method, pseudo measurement points Pi (i = 1, 2,..., N) and a design surface f (a, x) are used. “A” of the design surface f (a, x) means a parameter expressing the design surface, and “x” of the design surface f (a, x) means coordinates constituting the design surface.

  In the least square method, the pseudo measurement point Pi is rigidly moved by the parallel movement T and the rotation R, and an attitude that best matches the design surface f (a, x) is obtained. This posture is given by the translation T and the rotation R. “Determining the best matching posture” means mathematically minimizing the sum of squares of the shortest distance between the value of the pseudo measurement point Pi after moving the rigid body and the design surface f (a, x). To do.

In FIG. 8, the pseudo measurement point Pi that is rigidly moved by the parallel movement T and the rotation R is represented as a point “xi”. Further, a point on the design surface that gives the minimum distance between the point xi and the design surface f (a, x) is represented as “xi”. Further, the pseudo measurement point Pi is obtained as a predetermined position of the contactor 24 as described above. When the point “xi ′” is a true measurement point in consideration of the offset due to the shape of the contactor 24, the amount to be minimized by the least square method is “Σ | xi′−xi ″ | ² ”. As described above, the arrangement state of the DUT 4 can be estimated from the translation T and the rotation R obtained by the method of least squares.

[Effect of the shape measuring apparatus according to the embodiment]
Next, the effect of the shape measuring apparatus according to the embodiment will be described. In the shape measuring apparatus according to the embodiment, the control unit 41 preliminarily measures the displacement of the surface at each rotation angle of the object to be measured 4, and the measurement value acquired by the preliminary measurement and the object 4 to be measured previously stored are measured. The amount of deviation of the measured value from the design value is calculated from the design value. With the above configuration, the shape measuring apparatus according to the embodiment can determine the amount of deviation from the rotation axis of the DUT 4 with high accuracy with a simple configuration.

  Further, the control unit 41 adjusts the posture of the DUT 4 based on the calculated deviation amount, and rotates each DUT 4 while rotating the DUT 4 after the posture adjustment about the rotation axis. Measure the displacement of the surface at the corner. With the above configuration, the shape measuring apparatus according to the embodiment can quickly guarantee the accuracy of the measurement with a simple configuration.

  With the guarantee of the accuracy, the shape measuring apparatus according to the embodiment can measure various geometric tolerances. For example, the relationship (coaxiality / perpendicularity / runout / flatness) between the optical axis of the lens (surface reference on the upper surface) and the outer periphery of the lens can be obtained. For example, the relationship between the axis of the upper surface of the lens and the axis of its lower surface can be obtained. For example, centering can be performed on the upper surface of the lens, and the axis of the lower surface of the lens can be evaluated.

  Further, the shape measuring apparatus according to the embodiment is not a three-dimensional measuring machine that performs measurement by moving the XYZ axes, but a perfect circle in which the rotation accuracy of the θ axis (the behavior of the table surface moving up and down / left and right) is guaranteed. Since the degree measuring machine is used, the above-mentioned measurement specific to the rotating body can be performed with high accuracy.

[Other Embodiments]
As mentioned above, although the embodiment of the shape measuring apparatus has been described, the present invention is not limited to the above-described embodiment, and various modifications, additions, substitutions, and the like are possible without departing from the spirit of the invention. .

  DESCRIPTION OF SYMBOLS 1 ... Measuring machine main body, 2 ... Arithmetic processing unit, 3 ... Base, 4 ... Object to be measured, 5 ... Table, 6 ... Displacement detection device, 7 ... Operation part, 21 ... Column, 22 ... Slider, 23 ... Stylus, 24: contact, 31 ... arithmetic processing unit main body, 32 ... operation unit, 33 ... display screen.

Claims (3)

In the shape measuring apparatus for measuring the displacement of the surface at each rotation angle of the object to be measured while rotating the object to be measured made of a rotating body around a predetermined rotation axis,
Means for preliminarily measuring the displacement of the surface at each rotation angle of the object to be measured;
Means for calculating an amount of deviation of the measured value with respect to the design value from a measured value indicating the surface shape of the measured object obtained by the preliminary measurement and a design value of the measured object stored in advance;
Means for adjusting the posture of the object to be measured based on the calculated deviation amount;
And means for performing control for main measurement of the displacement of the surface at each rotation angle of the object to be measured while rotating the object to be measured after the posture adjustment about the rotation axis. Shape measuring device. In the shape measurement method for measuring the displacement of the surface at each rotation angle of the measurement object while rotating the measurement object made of a rotating body around a predetermined rotation axis,
Preliminarily measuring the displacement of the surface at each rotation angle of the object to be measured;
Calculating a deviation amount of the measured value from the measured value indicating the surface shape of the measured object acquired by the preliminary measurement and a previously stored design value of the measured object;
Adjusting the posture of the object to be measured based on the calculated shift amount;
And measuring the displacement of the surface at each rotation angle of the object to be measured while rotating the object to be measured after the posture adjustment about the rotation axis. A shape measurement program for measuring a displacement of a surface at each rotation angle of the measurement object while rotating the measurement object made of a rotating body around a predetermined rotation axis,
On the computer,
Preliminarily measuring the displacement of the surface at each rotation angle of the object to be measured;
Calculating an amount of deviation of the measured value with respect to the design value from a measured value indicating the surface shape of the measured object obtained by the preliminary measurement and a design value of the measured object stored in advance;
Adjusting the posture of the object to be measured based on the calculated shift amount;
And a step of performing a main measurement of a displacement of a surface at each rotation angle of the measurement object while rotating the measurement object after the posture adjustment around the rotation axis.

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