JP2009271030A - Shape measuring apparatus and shape measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measuring apparatus and a shape measuring method for determining a coordinate system of a rotating table while suppressing errors. <P>SOLUTION: The shape measuring apparatus includes the rotating table 50, a reference sphere 61b located at a distance h1 in a first direction from the surface of the rotating table 50, and a reference sphere 61c located at a distance h2 (h2>h1) in the first direction from the surface of the rotating table 50. A controller 31 rotates the rotating table 50 by 120° each time around a rotating shaft three times, and makes a contact 17a follow the reference spheres 61b, 61c at each 120° rotation. The controller 31 finds the center position O1 of a circle C1 passing the center positions Ma11-Ma13 of the reference sphere 61b, and the center position O2 of a circle C2 passing the center positions Ma21-Ma23 of the reference sphere 61c, to calculate a straight line A1 passing each center position O1, O2 as a Z<SB>T</SB>axis. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shape measuring device such as a three-dimensional measuring device that performs displacement measurement using a contact, and a shape measuring method.

  2. Description of the Related Art Conventionally, there is known a three-dimensional measuring apparatus that causes a contact to follow an object to be measured (hereinafter referred to as a workpiece) and measures the shape of the workpiece based on the contact between the contact and the workpiece. Furthermore, a three-dimensional measuring apparatus provided with a rotary table (rotary table) is also known (for example, see Patent Document 1). The rotary table is configured such that the work can be placed and the work can be rotated about the rotation axis.

  When performing measurement using the rotary table, it is necessary to set the coordinate system of the rotary table in advance. For registration of the coordinate system of the rotary table, a reference sphere (master ball) fixed to the upper end of the rotary table is usually used. For example, the three-dimensional measuring apparatus rotates the rotary table from a predetermined angle by 0 °, 120 °, and 240 °, and measures the center position of the reference sphere at each rotation angle. Subsequently, the three-dimensional measuring apparatus calculates a circular plane passing through the measured center position of the reference sphere and the center of the circular plane. The three-dimensional measuring apparatus calculates a normal passing through the center of the circular plane and perpendicular to the circular plane, and uses the normal as the Z axis of the coordinate system of the rotary table.

JP 2001-264048 A

  However, when the rotation axis of the rotary table swings around, using the above coordinate system setting method, the diameter value of the cylindrical axis measured at a position away from the upper surface of the rotary table by a predetermined length is It is obtained larger than the diameter value. That is, the conventional method for setting the coordinate system of the rotary table does not support the rotation of the rotary shaft, and has a large error and lacks reliability.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a shape measuring device and a shape measuring method for determining a coordinate system of a rotary table while suppressing errors.

  A shape measuring apparatus according to the present invention is a shape measuring apparatus for measuring a surface shape of an object to be measured, the position information acquiring unit acquiring position information based on contact between a contact and the object to be measured, and the object to be measured. The position information acquisition unit acquires a rotary table configured to be able to place a measurement object and rotating about a rotation axis, and a first position located at a first distance in a first direction from the surface of the rotary table. A first information providing unit configured to be capable of acquiring a second position located at a second distance longer than the first distance in the first direction from the surface of the turntable by the position information acquiring unit. A second information providing unit configured as described above, a drive control unit that controls driving of the contactor and the rotary table, and a coordinate system calculation unit that calculates coordinate axes constituting a coordinate system on the rotary table, The drive control unit The rotary table is rotated n times (360 / n) degrees (n: an integer of 3 or more) around the rotation axis, and the contact is provided with the first information each time the rotation table is rotated (360 / n) degrees. The coordinate system calculating unit obtains a first center of a first circle passing through the first position acquired by the first information providing unit, and the coordinate system calculating unit is configured to follow the second information providing unit and the second information providing unit. 2 Finding a second center of a second circle passing through the second position acquired by the information providing unit, and calculating a straight line passing through the first center and the second center as the coordinate axis. And

  With the above configuration, the shape measuring apparatus can calculate the coordinate axes that constitute the coordinate system on the rotary table.

  The first information providing unit is formed in a spherical shape with a first columnar part extending in the first direction from the surface of the rotary table and a first length from the surface of the rotary table with the first length at the center of the first columnar part. The second information providing unit includes a second columnar part extending in the first direction from the surface of the rotary table, and the second length from the surface of the rotary table. It is good also as a structure provided with the 2nd spherical part which provided the center in the 2 columnar part and was formed in the spherical shape.

  The shape measuring method according to the present invention includes a position information acquisition unit that acquires position information based on contact between a contact and the object to be measured, and is configured to be able to place the object to be measured and rotates about a rotation axis. A rotary table, a first information providing unit configured to be able to acquire a first position located at a first distance in a first direction from the surface of the rotary table by the position information acquiring unit, and a surface of the rotary table A second information providing unit configured to be able to acquire a second position located at a second distance longer than the first distance in the first direction by the position information acquiring unit, the contact and the rotation A shape that measures the surface shape of the object to be measured using a shape measuring device that includes a drive control unit that controls driving of the table and a coordinate system calculation unit that calculates coordinate axes that constitute the coordinate system on the rotary table. Measurement method , The drive control unit rotates the rotary table around the rotation axis by (360 / n) degrees (n: integer of 3 or more) n times, and every time the rotation table is rotated (360 / n) degrees, the contact is performed. Obtaining the first center of the first circle passing through the first position acquired by the first information providing unit, the step of causing the child to follow the first information providing unit and the second information providing unit, Obtaining a second center of a second circle passing through the second position acquired by the second information providing unit, and calculating a straight line passing through the first center and the second center as the coordinate axis; It is characterized by providing.

  ADVANTAGE OF THE INVENTION According to this invention, the shape measuring apparatus and shape measuring method which suppress an error and determine the coordinate system of a rotary table can be provided.

  Hereinafter, a shape measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Configuration of the shape measuring apparatus according to the embodiment)
FIG. 1 is a perspective view showing a schematic configuration of a shape measuring apparatus according to an embodiment of the present invention. This shape measuring apparatus includes a three-dimensional measuring machine 1 and a computer 2 that drives and controls the three-dimensional measuring machine 1 to take in necessary measurement values and execute arithmetic processing necessary for shape processing.

  The coordinate measuring machine 1 is configured as shown in FIG. 1, for example, and a surface plate 11 is placed on the base table 10 so as to coincide with a horizontal plane with the upper surface as a base surface. A beam 13 extending in the X-axis direction is supported by the upper ends of beam supports 12a and 12b which are erected from both ends of the board 11. The lower end of the beam support 12 a is driven in the Y-axis direction by the Y-axis drive mechanism 14. Further, the lower end of the beam support 12b is supported on the surface plate 11 by an air bearing so as to be movable in the Y-axis direction. The beam 13 supports a column 15 extending in the vertical direction (Z-axis direction). The column 15 is driven along the beam 13 in the X-axis direction. The column 15 is provided with a spindle 16 so as to be driven along the column 15 in the Z-axis direction. A contact type probe 17 is attached to the lower end of the spindle 16. In addition, a contact 17 a having an arbitrary shape, for example, an elliptical sphere shape, is formed at the tip of the probe 17. The contact 17a is used to measure the workpiece 71, and the computer 2 takes in the XYZ coordinate values associated with the measurement.

  At a predetermined position on the surface plate 11, a surface plate reference sphere 61a used for setting a machine coordinate system described later is mounted. The surface plate reference sphere 61a is a steel ball, a ceramic sphere, or the like. The radius of the reference sphere 61a for the surface plate is known. That is, the three-dimensional measuring machine 1 can uniquely identify the center position of the reference sphere 61a for the platen by measuring the contact 17a.

  The reference sphere 61a for the surface plate is provided with a predetermined height h0 in a direction orthogonal to the upper surface of the turntable 11 from the upper surface of the surface plate 11 via the columnar portion 62a for the surface plate. The platen portion 62a for the surface plate is fixed to the surface plate 11 by the surface plate chuck 63a.

  FIG. 2 is a cross-sectional view of the surface plate 11 of the three-dimensional measuring machine 1. As shown in FIG.1 and FIG.2, the surface plate 11 has the recessed part 11A in the upper surface. A rotary table 50 is provided in the recess 11A. The rotary table 50 is configured such that the work 71 can be placed and the work 71 can rotate about the rotation axis H. The turntable 50 has a through hole 50A at the center thereof. The through hole 50 </ b> A is provided for placing the long work 71 on the turntable 50.

  On the turntable 50, a first reference sphere 61b and a second reference sphere 61c are provided. The first reference sphere 61b and the second reference sphere 61c are steel balls, ceramic balls, or the like. The radii of the first reference sphere 61b and the second reference sphere 61c are known. That is, the three-dimensional measuring machine 1 can uniquely determine the center positions of the first reference sphere 61b and the second reference sphere 61c by measuring the scanning of the contact 17a.

  The first reference sphere 61b is provided with a first height h1 in a direction perpendicular to the upper surface of the turntable 50 from the upper surface of the turntable 50 via the first columnar portion 62b. The first columnar part 62b is fixed to the rotary table 50 by the first chuck 63b. The first reference sphere 61b (first information providing unit) is configured to be able to acquire a first position located at a first distance in the first direction from the surface of the rotary table 50 by the control unit 31 (CPU 31 described later). ing.

  The second reference sphere 61c is provided with a second height h2 in a direction orthogonal to the upper surface of the turntable 50 from the upper surface of the turntable 50 via the second columnar portion 62c. The second height h2 is higher than h1 than the first height. The second columnar part 62c is fixed to the rotary table 50 by the second chuck 63c. The second reference sphere 61c (second information providing unit) gives the control unit 31 (a CPU 31 to be described later) a second position located at a second distance longer than the first distance in the first direction from the surface of the turntable 50. It is configured to be obtainable.

  The first reference sphere 61b (first columnar portion 62b, first chuck 63b) and the second reference sphere 61c (second columnar portion 62c, second chuck 63c) have a predetermined length from the center (rotation axis H) of the rotary table 50. It is provided at a remote location. The second reference sphere 61c (second columnar portion 62c, second chuck 63c) is 180 ° from the center (rotation axis H) of the first reference sphere 61b (first columnar portion 62b, first chuck 63b) and the rotary table 50. It is provided at the opposite position.

  Next, the configuration of the computer 2 will be described. As shown in FIG. 1, the computer 2 includes a computer main body 21, a keyboard 22, a mouse 23, a CRT 24, and a printer 25.

  The computer main body 21 is configured as shown in FIG. FIG. 3 is a block diagram showing a configuration of the computer main body 21 according to the embodiment of the present invention.

  The computer main body 21 mainly includes a CPU (control unit) 31, a RAM 32, a ROM 33, an HDD (storage unit) 34, and a display control unit 35. In the computer main body 21, code information and position information input from the keyboard 22 and the mouse 23 are input to the CPU 31 via the I / F 36a. The CPU 31 executes a measurement execution process, a rotation table coordinate system calculation process, which will be described later, and the like according to a macro program stored in the ROM 33 and various programs stored in the RAM 32 from the HDD 34 via the I / F 36b.

  The CPU 31 controls the three-dimensional measuring machine 1 through the I / F 36c according to the measurement execution process. The HDD 34 is a recording medium that stores various control programs. The RAM 32 stores various programs and provides a work area for various processes. Further, the CPU 31 displays the measurement result and the like on the CRT 24 via the display control unit 35.

The CPU (control unit) 31 has various functions by reading various programs from the HDD 34 and executing the programs. The CPU (control unit) 31 functions as a position information acquisition unit that acquires position information based on the contact between the contact 17 a and the work 71. The CPU (control unit) 31 functions as a drive control unit that controls driving of the contact 17 a and the rotary table 50. The CPU 31 (control unit) functions as a coordinate system calculation unit that calculates a Z _T axis (coordinate axis) constituting a coordinate system (rotation table coordinate system (X _T , Y _T , Z _T )) on the rotation table 50.

Further, the CPU 31 (control unit) rotates the rotary table 50 around the rotation axis H by 120 ° three times, and the contact 17a follows the first reference sphere 61b and the second reference sphere 61c each time the rotary table 50 is rotated by 120 °. Let Further, the CPU 31 (control unit) obtains the first center of the first circle passing through the center position of the acquired plurality of first reference spheres 61b, and passes through the center position of the acquired plurality of second reference spheres 61c. obtains a second center of the second circle, it calculates the straight line a passing through the first center and the second center as Z _T axis (axes).

(Explanation of coordinate system)
Next, a coordinate system used in the present embodiment will be described with reference to FIG. FIG. 4 is a diagram for explaining a coordinate system according to the present embodiment.

In the present embodiment, the scale coordinate system (X _S , Y _S , Z _S ), machine coordinate system (X _M , Y _M , Z _M ), rotary table coordinate system (X _T , Y _T , Z _T ), rotation A time table coordinate system (X _Tθ , Y _Tθ , Z _Tθ ) and a work coordinate system (X _W , Y _W , Z _W ) are set.

Scale coordinate system _{(X S, Y S, Z} S) is the coordinate system of the three-dimensional measuring machine 1 (machine) for a preset absolute position as the origin _{O S.} Machine coordinate system (X _M , Y _M , Z _M )
Is a scale coordinate system as the center position of the surface plate reference sphere 61a the origin _{O M (X S, Y S} , Z S) coordinate system is moved parallel.

Rotating table coordinate system _{(X T, Y T, Z} T) is a coordinate system in which the center of the upper surface of the rotary table 50 when the rotation angle is 0 ° as the origin _{O T.} The rotary table coordinate system (X _T , Y _T , Z _T ) does not change even when the rotary table 50 rotates. Rotating table coordinate system _{(X T, Y T, Z} T) is the center of the rotary table 50 as the origin _{O T,} the central axis of the rotary table 50 is an orthogonal coordinate system with _{Z T.}

During rotation table coordinate system _{(X Tθ, Y Tθ, Z} Tθ) is a coordinate system in which the center of the rotating table 50 when rotating the rotary table 50 by the rotation angle θ as the origin O _T. The rotating table coordinate system (X _Tθ , Y _Tθ , Z _Tθ ) changes each time the rotating table 50 rotates.

Work coordinate system _{(X W, Y W, Z} W) is a coordinate system in which the upper surface of the workpiece 71 _X W _{Y W} plane, the predetermined position of the upper surface of the workpiece 71 as the origin _{O W.}

  That is, as shown in FIG. 4, an arbitrary point P positioned above the surface plate 11 can be expressed in various coordinate systems as shown in Equation 1 below.

Next, a method of calculating a vector extending in the positive direction along the axis of each coordinate system from the origin of each coordinate system will be described. In the following, the vector X _S in the scale coordinate system (X _S , Y _S , Z _S ) is expressed as (Equation 2) shown below. A vector X _M in the machine coordinate system (X _M , Y _M , Z _M ) is expressed as (Equation 3) shown below. Rotating table coordinate system _{(X T, Y T, Z} T) vector _{X T} in is represented as shown below (Equation 4). A vector X _Tθ in the rotating table coordinate system (X _Tθ , Y _Tθ , Z _Tθ ) is expressed as (Formula 5) shown below. A vector X _W in the workpiece coordinate system (X _W , Y _W , Z _W ) is expressed as (Equation 6) shown below.

Furthermore, the vector _{O M} directed from the origin _{O S} to the origin _{O M} is represented as shown below (Equation 7). Vector _{O T} directed from the origin _{O M} to the origin _{O T} is represented as shown below (Equation 8). Vector _{O W} extending from the origin _{O T} to the origin _{O W} is expressed as shown below (Equation 9).

Vector X _M can be expressed as shown below (Equation 10).

Vector X _T can be expressed as shown below (Equation 11).

Transformation matrix _{M 1} is represented as shown below (Equation 12). In (Equation 12), the first line shows the unit vector component of the _XT axis, the second line shows the unit vector component of the _YT axis, and the third line shows the unit vector component of the _ZT axis. . Coordinate system, because it is right-handed, the value of the determinant of the transformation matrix M ₁ is, must be a "+ 1".

The vector _XTθ can be expressed as (Formula 13) shown below.

Rotation matrix _{M 2} can be expressed as shown below (Equation 14). Coordinate system, because it is right-handed, the value of the determinant of the rotation matrix M ₂ is, must be a "+ 1".

Vector X _W can be expressed as shown below (Equation 15).

Transformation matrix _{M 3} represents, expressed as shown below (Equation 16). In (Equation 16), the first line shows the unit vector component of the _XW axis, the second line shows the unit vector component of the _YW axis, and the third line shows the unit vector component of the _ZW axis. . Coordinate system, because it is right-handed, the value of the determinant of the transformation matrix M ₃ is, must be a "+ 1".

From above (Equation 10) to (Equation 16), the vector _{X W} can be expressed as shown below (Equation 17).

(Calculation processing of rotation table coordinate system (X _T , Y _T , Z _T ) in the embodiment)
Next, with reference to FIG. 5, the calculation process of the rotation table coordinate system (X _T , Y _T , Z _T ) in the embodiment will be described. FIG. 5 is a flowchart showing a calculation process of the rotary table coordinate system (X _T , Y _T , Z _T ) in the embodiment. Note that the processing shown in FIG. 5 is performed by the control unit 31 executing a program or the like stored in the storage unit.

  As shown in FIG. 5, first, the control unit 31 sets the rotation angle of the turntable 50 to a predetermined angle (step S101).

  Next, the controller 31 causes the contact 17a to follow the first reference sphere 61b as shown in the first state I of FIG. 6, and measures the position of the sphere center of the first reference sphere 61b (step S102). . Subsequently, as shown in the second state II of FIG. 6, the control unit 31 causes the contact 17a to follow the second reference sphere 61c, and measures the center of the second reference sphere 61c (step S103). .

  Next, the control unit 31 determines whether or not the rotary table 50 has been rotated 360 ° (step S104). If the control unit 31 determines that the rotary table 50 is not rotated 360 ° (step S104, N), the control unit 31 rotates the rotary table 50 by 120 ° (step S105), and repeats the processing from step S102 again. To do. On the other hand, when determining that the rotary table 50 has been rotated 360 ° (step S104, Y), the control unit 31 executes a process of step S106 described later.

  Here, FIG. 7 is a top view schematically showing the rotation of the turntable 50 and the measurement of the first and second reference balls 61b and 61c accompanying the rotation. Through the steps S101 to S105, as shown in FIGS. 7A to 7C, the rotary table 50 determines the position of the first reference sphere 61b and the position of the second reference sphere 61c. It is measured at three points rotated by 0 °, 120 °, and 240 °. The ball center position is determined from position information of at least four points.

  FIG. 8 is a diagram illustrating the position of the center of the first reference sphere 61b and the position of the center of the second reference sphere 61c as viewed from the direction of the arrow C1 in FIG. As shown in FIGS. 8A to 8C, the rotation axis H of the rotary table 50 and the ideal axis center with changes in the rotation angle (0 °, 120 °, 240 °) of the rotary table 50. Between Ho, it changes over the angles φ1 to φ3. That is, a swinging error occurs on the rotation axis H of the rotary table 50. As shown in FIG. 8A, when the rotary table 50 is rotated by 0 °, the center position Ma11 of the first reference sphere 61b is measured, and the center position Ma21 of the second reference sphere 61c is measured. Similarly, as shown in FIG. 8B, when the rotary table 50 rotates by 120 °, the spherical center position Ma12 of the first reference sphere 61b is measured, and the spherical center position Ma22 of the second reference sphere 61c is measured. Similarly, as shown in FIG. 8C, when the rotary table 50 rotates by 240 °, the center position Ma13 of the first reference sphere 61b is measured, and the center position Ma23 of the second reference sphere 61c is measured.

  Subsequent to step S104, the control unit 31, as shown in FIG. 9, is based on the measured three ball center positions Ma11 to Ma13 of the first reference sphere 61b, and passes the first ball center positions Ma11 to Ma13. A circle C1 is calculated. Further, the control unit 31 calculates the first center position O1 of the first circle C1 (step S106).

  Subsequently, as illustrated in FIG. 9, the control unit 31 moves the second circle C2 passing through the center positions Ma21 to Ma23 based on the measured three center positions Ma21 to Ma23 of the second reference sphere 61c. calculate. Further, the control unit 31 calculates the second center position O2 of the second circle C2 (step S107).

  Next, as shown in FIG. 9, the control unit 31 calculates a straight line A of the turntable 50 that passes through the first center position O1 of the first circle C1 and the second center position O2 of the second circle C2. (Step S108).

Then, the control unit 31 calculates the rotary table coordinate system (X _T , Y _T , Z _T ) based on the straight line A of the rotary table 50 (step S109). In step S109, the control unit 31, a first center position O1 and origin _{O T.} The control unit 31 sets the direction along the straight line A from the origin O _T (center position O1) to the second center position O2 as the Z _T axis (coordinate axis). For example, the control unit 31, and _{X T} axis parallel to the direction B from the origin _{O T} (first center position O1). Here, the direction B refers to the first reference sphere 61b when the rotation angle of the rotary table 50 is 120 ° from the spherical center position Ma11 of the first reference sphere 61b when the rotation angle of the rotary table 50 is 0 °. This is the direction toward the ball center position Ma12. The control unit 31, _{Z T} axis, and an axis orthogonal to the _{X T} axis and _{Y T} axis.

After calculation of the rotary table coordinate system (X _T , Y _T , Z _T ), as shown in FIG. 10, from the rotary table 50, the first reference sphere 61b (first columnar part 62b, first chuck 63b) and The second reference sphere 61c (second columnar part 62c, second chuck 63c) is removed. Subsequently, the work 71 is inserted into the through hole 50 </ b> A of the turntable 50, and the work 71 is fixed by the chuck 81 on the upper surface of the turntable 50. Then, as shown in the third state III of FIG. 10, the shape of the work 71 is measured by the contact 17a.

(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. The shape measuring apparatus according to the embodiment calculates the rotary table coordinate system (X _T , Y _T , Z _T ) as described above in consideration of the run-out error. Therefore, the shape measuring apparatus according to the embodiment calculates the rotary table coordinate system (X _T , Y _T , Z _T ) while suppressing the error even when a swing error occurs in the rotary table 50. Can do.

(Other embodiments)
As mentioned above, although embodiment of invention was described, this invention is not limited to these, A various change, addition, substitution, etc. are possible within the range which does not deviate from the meaning of invention.

  For example, the shape measuring apparatus according to the present invention is not limited to the configuration having the first reference sphere 61b. The shape measuring apparatus according to the present invention has a configuration in which the controller 31 can acquire a first position located at a first distance in the first direction from the surface of the rotary table 50, instead of the first reference sphere 61b. If you do.

  For example, the shape measuring apparatus according to the present invention is not limited to the configuration having the second reference sphere 61c. In the shape measuring apparatus according to the present invention, instead of the second reference sphere 61c, the control unit 31 sets a second position located at a second distance longer than the first distance in the first direction from the surface of the turntable 50. What is necessary is just to have the structure which can be acquired.

  For example, the shape measuring apparatus according to the present invention is not limited to the configuration in which the rotary table 50 is rotated by 120 °. The shape measuring apparatus according to the present invention rotates the rotary table 50 around the rotation axis H by (360 / n) degrees (n: integer of 3 or more) n times, and contacts each time it is rotated (360 / n) degrees. Any configuration may be used as long as the child 17a follows the first reference sphere 61b and the second reference sphere 61c.

  For example, the shape measuring apparatus according to the present invention rotates the rotary table 50 360 degrees to measure the ball center positions Ma11 to Ma13 related to the first reference sphere 61b, and then further rotates the rotary table 50 360 degrees. The structure which measures the ball | bowl center position Ma21-Ma23 which concerns on the 2 reference sphere 61c may be sufficient.

It is a schematic block diagram of the shape measuring apparatus which concerns on embodiment of this invention. It is sectional drawing of the surface plate 11 of the three-dimensional measuring machine 1 which concerns on embodiment. It is a functional block diagram of the computer main body 21 which concerns on embodiment. It is a figure explaining each coordinate system. Rotating table coordinate system of the embodiment _{(X T, Y T, Z} T) is a flowchart illustrating a process for calculating. It is a figure which shows operation | movement of the contactor 17a which concerns on embodiment. It is a top view which shows the outline of the measurement of 1st, 2nd reference ball | bowl 61b, 61c accompanying rotation of the turntable 50 of embodiment, and its rotation. It is a figure which shows the ball | bowl center position of the 1st reference ball | bowl 61b seen from the arrow C1 direction of FIG. Rotating table coordinate system of the embodiment _{(X T, Y T, Z} T) is a diagram for explaining the outline calculated. It is a figure explaining the outline of the shape measurement of the workpiece | work 71 which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Three-dimensional measuring machine, 2 ... Computer, 10 ... Isolation table, 11 ... Surface plate, 12a, 12b ... Beam support, 13 ... Beam, 14 ... Y-axis drive mechanism, 15 ... Column, 16 ... Spindle, 17 DESCRIPTION OF SYMBOLS ... Probe, 17a ... Contact, 21 ... Computer main body, 22 ... Keyboard, 23 ... Mouse, 24 ... CRT, 25 ... Printer.

Claims (3)

A shape measuring device for measuring the surface shape of an object to be measured,
A position information acquisition unit that acquires position information based on contact between the contact and the measurement object;
A rotary table configured to be capable of placing the object to be measured and rotating about a rotation axis;
A first information providing unit configured to be able to acquire a first position located at a first distance in a first direction from the surface of the rotary table by the position information acquiring unit;
A second information providing unit configured to be able to acquire a second position located at a second distance longer than the first distance in the first direction from the surface of the rotary table;
A drive controller for controlling the drive of the contact and the rotary table;
A coordinate system calculation unit for calculating coordinate axes constituting a coordinate system on the rotation table,
The drive control unit
The rotary table is rotated n times (360 / n) degrees (n: an integer of 3 or more) around the rotation axis, and the first information is provided to the contact each time the rotary table is rotated (360 / n) degrees. Follow the second information providing unit,
The coordinate system calculation unit
A second circle passing through the second position acquired by the second information providing unit by obtaining a first center of the first circle passing through the first position acquired by the first information providing unit. The shape measuring device is characterized in that a second center is obtained and a straight line passing through the first center and the second center is calculated as the coordinate axis. The first information providing unit includes:
A first columnar portion extending in the first direction from the surface of the rotary table;
A first spherical portion formed in a spherical shape with a center on the first columnar portion having the first length from the surface of the rotary table;
The second information providing unit includes:
A second columnar portion extending in the first direction from the surface of the turntable;
The shape measuring apparatus according to claim 1, further comprising: a second spherical portion that is formed in a spherical shape with a center at the second columnar portion having the second length from the surface of the rotary table. A position information acquisition unit that acquires position information based on contact between the contact and the object to be measured;
A rotary table configured to be capable of placing the object to be measured and rotating about a rotation axis;
A first information providing unit configured to be able to acquire a first position located at a first distance in a first direction from the surface of the rotary table by the position information acquiring unit;
A second information providing unit configured to be able to acquire a second position located at a second distance longer than the first distance in the first direction from the surface of the rotary table;
A drive controller for controlling the drive of the contact and the rotary table;
A shape measuring method for measuring a surface shape of the object to be measured using a shape measuring device comprising: a coordinate system calculating unit that calculates a coordinate axis constituting a coordinate system on the rotating table,
Each time the drive control unit rotates the rotary table around the rotation axis by (360 / n) degrees (n: integer of 3 or more) n times, and each time the rotary table is rotated (360 / n) degrees, the contactor Following the first information providing unit and the second information providing unit,
A second circle passing through the second position obtained by the second information providing unit by obtaining a first center of the first circle passing through the first position obtained by the first information providing unit. And calculating a straight line passing through the first center and the second center as the coordinate axis. A shape measuring method comprising:

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