JPS62163914A - Shape measuring apparatus - Google Patents

Abstract

PURPOSE:To enable the highly accurate measuring, corresponding to the accuracy on the side of a measuring section, of a shape while being economical without being affected by a rotational position accuracy of an object to be measured, by providing a detector for detecting the angle of rotation of the object being measured to correct deviation of the angle on the measuring section side. CONSTITUTION:A positioner 5 has a highly accurate encoder 26 connected directly to a rotating shaft to detect the angle of rotation thereof. The detector 26 detect the actual angle of rotation. A control section 28 performs a positioning control in the three axes - X, Y and Z - at a shape measuring section 4 and theta axis of the positioner 5 and has a measuring control section 15 and driving control sections 16a, 16b, 16c and 23. The driving control section 16a controls a servo-motor for setting a position with respect to the X-axis of the shape measuring section 4, the driving control section 16b controls a servo-motor 14 for setting a position with respect to the Y-axis, the driving control section 16c controls a servo-motor 13 for setting a position with respect to the Z-axis and furthermore, the drive control section 23 controls a servo-motor 21 for setting the rotating position of the positioner 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shape measuring device, and in particular, the present invention relates to a shape measuring device, and in particular, a measuring head fixed to an I1I11 fixed axis is brought close to the surface of the measured object by rotating the measured object. The present invention relates to a shape measuring device that measures the amount of displacement, etc. of an object to be measured by bringing it into contact with the object, and is capable of performing more accurate measurements without being affected by the accuracy of positioning the rotational position of the object.

[Prior Art] As a conventional technology of this type, there is a three-dimensional shape meter 71tll device. This three-dimensional shape measuring device has, for example, a robot with 1'' L and 3 axes JF2, and a measurement head (ri/notch sensor) is attached to the tip of the arm.

When measuring the shape of a propeller as an object to be measured in such a measuring device, for example, the blade is rotated by a positioner and stopped at the blade position to be measured, and the column (support) that constitutes the two axes Y and Z is used. Move the arm left and right (X-axis direction), and lower the arm that makes up the Y-axis with a touch sensor attached to the tip.

1) After 11, the shape of the object to be measured (propeller) is measured by touching the wing surface by moving freely and reading the linear scale coordinate values of the three axes x, y, and z at the moment of touch. .

Here, positioning accuracy when moving the shape measuring device in the three axes x, y, and z is achieved through highly accurate linear bearings, ball screws, linear scales, servo motors, etc., and extremely accurate positioning is achieved. It can be achieved. This allows positioning, for example, on the order of several μ to several tens of μli.

[Problems to be Solved] On the other hand, there is a problem with the positioning accuracy of the bomb 7FI which determines the position of the object to be measured.

An example of position control of a conventional positioner is shown in a block as shown in FIG. In the figure, numeral 5 is a positioner, which transfers the rotational force of the servo motor 21 to the pinion 20. It is rotated by being received via the gear 19.

Here, 23 is a drive control section of the servo motor 21, 25 is its feedback signal line, and 15 is
This is the measurement control section.

Here, if the propeller of the object to be measured becomes heavy and large in size, GD2 becomes large, and the positioner 5 needs to have a large torque as a driving device. Therefore, as shown in FIG. 5, the torque of the servo motor 21 is adjusted to
0. The gear 19 is used to increase the size and move the positioner 5.

Because of this relationship, even if the encoder 22, which is a rotary encoder or the like, is used to determine the rotational angle with high accuracy and determine the rotational position, the pinion 21. Lost motion occurs due to backlash such as bank crash in the reduction mechanism portion of the gear 19, and a rotation angle positioning accuracy of about 1 to IO minutes at most can only be achieved.

Furthermore, assuming that the propeller dimensions are 2 m in radius, the positioning accuracy at the outermost diameter will be as given by the following equation.

GO+80 In such a case, it is impossible to achieve higher accuracy than this, and it is unreasonable to desire higher shape measurement accuracy.

[Purpose of the Invention] This invention solves the problems of the prior art, and even if the rotational positioning accuracy of the object to be measured is lower than the positioning accuracy of the measuring side, it is not limited to this. It is an object of the present invention to provide a shape measuring device that is capable of performing more accurate measurements.

[Means for Solving the Problems] The feature of the present invention is to correct the rotational deviation IIL of the object to be measured, and to determine the rotational position of the object to be measured by the shape measuring device. A high-performance encoder detects the deviation in the rotation angle of the shank, and the measurement unit corrects the deviation in the coordinate position of the measurement point according to this detected value, making highly accurate shape measurement possible. .

Therefore, the means of the shape measuring device of the present invention for achieving the above object is to control a moving mechanism that moves the measuring head in a plane parallel to the rotary table (at least in one direction). It has a control unit that controls moving the head in one direction and setting the rotary table to a target rotation position, and a detector that detects the rotation angle of the object to be measured, and the control unit controls the rotation angle of the object to be measured. The correction M for the positional deviation of the measuring head in one direction is calculated based on the detection signal from the measuring head and information on the target rotational position, and control is performed to correct the position of the measuring head.

[Function] In this way, by providing a detector to detect the rotation angle of the object to be measured, the angle deviation can be detected! Since 11 is corrected on the measurement unit side, economical shape measurement with high viscosity corresponding to the accuracy of the measurement unit is possible without being affected by the rotational positioning accuracy of the object to be measured. becomes.

[Example] Please refer to the drawings below for an example of this invention! ((1) will be explained in detail.

FIG. 1 is a block diagram centered on positioner (0 axis) control in a shape measuring device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of the overall configuration of the shape measuring device, and FIG. Figure 3 is a block diagram of the Y-axis control, and Figure 4 is
FIG. 3 is an explanatory diagram of measurement points of the object to be measured. Note that the same parts as in FIG. 5 above are indicated by the same reference numerals.

In FIG. 2, ■ is a shape meter 4 (+1 device,
The shape measuring mechanism consists of a control section 28 and a shape measuring mechanism 11111 shown in FIG. The fixed part 4 and the positioner 5 are placed on the bed 6-1r, and the position of the phase 7Z is accurately determined.

Reference numeral 7 in FIG. 1 is the base of the shape measuring section 4, and is a lower frame that constitutes the Y axis of the shape measuring section 4, and has a built-in linear bearing, ball screw, etc.

Reference numeral 7a denotes a linear scale, which is attached to the base 7 on the X-axis direction side, and 8, a travel frame, which runs on the base 7t in the X-axis direction via an lJ near bearing. Furthermore, a scale sensor 8a is attached to the side surface of the travel frame 8.

The column 9 is fixed perpendicularly to the travel frame 8-1-, and includes linear bearings that constitute two axes of the shape measuring section 4;
It has a built-in ball screw. In this column 9, the Z
A linear scale 9a is attached to the side surface in the axial direction, and a servo motor 13 is attached to the top of the column 9.
It is connected and fixed with a ball screw.

On the other hand, 10 is a saddle that runs in the Z-axis direction close to the linear scale 9a of the column 9.

This saddle 10 has a scale sensor 10a on its side.
is installed, and a scale sensor "l-10b" is installed in front of it.
is installed.

The arm 11 constitutes the Y axis of the shape measuring section 4, has a built-in linear scale, a ball screw, etc., and is attached to the saddle 10 via the linear scale. and arm 1
A touch sensor 12 (measuring head) is attached to the tip of the probe 1, and comes into contact with the surface of the blade 3 of the propeller 2, which is the object to be measured.

Further, a servo motor 14 is fixed to the rear part of the arm 11 in connection with a Y-axis ball screw, and as shown in FIG. It matches.

On the other hand, as shown in FIG. 1, a high-precision encoder (detector) 26 for detecting the rotation angle is attached to the positive 7E15 and is directly connected to its rotation axis.
Detects the actual rotation angle.

Here, the shape measuring device I first calculates the total value d (11) of the propeller 2 as a constant object when performing
Rotate with and stop at the blade position to be measured.

Next, column 9, which constitutes the three columns x, y, and z. Arm 1
1 is moved left and right and up and down to touch the wing surface of the fixed object using the touch sensor 12. Then, the linear scale coordinate values of the three axes x, y, and z at the moment of touch are read. With this, the shape of the propeller 2 is measured.

Now, the control section 28 shown in FIG.
5, and drive control sections 18a, 16b, 16c, and 23. Here, the drive control section lea is the Y of the shape measurement section 4.
The drive control unit 16b controls the servo motor 14 that sets the position about the axis, and the drive control unit≦18c controls the servo motor 13 that sets the position about the Z axis. control. Furthermore, the drive control unit 23 controls the servo motor 21 to set the rotational position (position about the θ axis) of the positive shifter 5.
control.

Here, each drive control ff1N 6 a, l 8 b, 1
8c and 23 each consist of an operational amplifier, etc., and each drive control section generates and amplifies a deviation signal between the target signal from the measurement control section 15 and the feedback signal of each scale sensor. , servo motor 13
, 14.23, etc. In addition, a total of 4111 control units 1
5 is equipped with a microprocessor, 7, etc., and the control program realizes the 1 mark position control means 15a and the correction amount calculation means 15b, and the positioning I of the positioner 5 is realized.
The Y-axis and Y-axis position correction control is performed in accordance with the Fi difference.

Next, positioning control of the positioner 5 will be explained based on FIG. 1. The 0-axis coordinate values of a total of 1lIII points from the measurement control section 15 are attached to the bend 6 via the drive control section 23 as a target signal. The signal is input to the servo motor 21 and rotates the pinion 20 attached to the output shaft of the servo motor 21. Gear 1 that meshes with this
9 rotates and the positioner 5 has the gear 19 attached.
The propeller 2 is set at a predetermined angular position by rotating the rotation axis of the propeller 2.

Here, the rotation speed of the servo motor 21 during this rotational positioning is determined by a detector (encoder) directly connected to the rotation axis.
22, and this detection signal is manually input to the drive control section 23 via the feedback signal line 25.

The drive control unit 23 compares this detection signal value with the target signal M from the measurement control unit 15, generates a deviation signal b (with respect to the rotation h1 of the servo motor 22), amplifies it, and outputs it. As a result, the rotation of the servo motor 22 is stopped when the deviation signal fit becomes zero, and the servo motor 22 is positioned at the target position.

Therefore, the servo motor 22 is operated by the signal amount (control signal) from the measurement control section 15. At this time, since the positioner 5 is rotated via the pinion 20 and the gear 19, a slight rotational error occurs due to lost motion due to bumps, bumps, etc. This becomes the position coordinate error of the measurement point.

The position coordinate error caused by the rotation angle error △0 is (△Xn+
If the relationship is shown in Figure 4 as Δyn), ΔXn,
Δyn is expressed by the following formula.

Δx=xn'-xn=R(cos(On-Δθn)-cosθn)...
・・・・・・・・・(1) Δy=yn'-yn :R(sin(on-ΔOn)-5lnOn)
(2) Here, let the measurement point of the blade be Pn, its radius be R1, and the X and Y coordinate values of the measurement point Pn be (xn + yn). On the other hand, position Pn' is measured at point P with rotation angle error Δ0.
Let n be the actual shifted position, and calculate the X, Y of this position Pn'
Let the coordinate value be (xn'+Yn').

Further, On is the target rotation angle from the measurement control unit 15, and is the angle formed by the angle reference line oO' and OPn. And (On-ΔOn) is the actual rotation angle, which is detected by the detector 26.

By the way, the X and Y coordinate values (xn.

Vn) and the X, Y coordinate values (xn
'+yn') is as follows.

xn = Rcosθn ・・・・・・・・・
...(3) yi = R5lnOn
・・・・・・・・・・・・(4)xn'
=R cos(On −Δθ) ・・・・・・・・・
...(5) yn' = Rsln((7n −Δ
0 ) ・−・−:・−・−(G ) Therefore,
From the above formulas (3) to (6), 1δ coordinate error △Xn, Δ
When yn is determined, it becomes as shown in Equation (I)9 and Equation (2).

As seen in equations (1) and (2), the position coordinate error △Xn
+Δyn becomes the measurement point error, which becomes the shape measurement error of shape measurement ■ζ4. Therefore, this error is corrected for the Y-axis and the Y-axis.

Next is the Y-axis, which is subject to such position correction.

Position control on the Y axis, etc. will be explained.

By the way, the positioning of the three axes of X, Y, and Z in the shape measuring device 1 is performed independently by the control unit 28, and the control method is the same. Therefore, in the following explanation, the Y axis of the shape measuring section 4 will be used as a representative, and the explanation about the X axis will be omitted. Note that the control for the Z axis is also controlled by the X machine.

It is similar to the Y axis.

Y-axis control is feedback control performed by generating a deviation value with respect to the target value, similar to the control of the +If positioner. To explain this according to FIG. 3, measurement control
The axial coordinate values of the measurement points from fi<15 are input to the drive control unit 16b as the 1-1 beam signal, and the drive control unit 16b
The signal is output to the servo motor 14 via. As a result, the ball screw itb rotates, and the ball screw rotates by that amount.) 1
0c moves, and the arm 11 shifts in the Y-axis direction.

This shift m is detected by the relationship between the linear scale lla and the scale sensor 10b, and is manually input to the drive control m<16b via the feed bank signal line 18.

The drive control section 18b generates a deviation signal amount between the target signal amount from the measurement control section 15 and the shift ffi of the arm 11, amplifies it, and outputs it. Therefore, the rotation of the servo motor 14 will stop when the deviation signal amount becomes zero. That is, the arm 11 receives the signal r3. from the measurement control section 15. 'Move again.

Therefore, to explain the process of correcting the position error for the Y-axis and the object to be measured on the Y-axis, the 11 mark position control means 15a of the measurement control unit 15 sends a signal regarding the 1" mark angle θ to the correction h1 calculation means 15b. do.

The correction tit calculation means 15b calculates the position coordinate error based on equations (1) and (2) based on the information about the target angle On and the actual positioning angle (θn-ΔO) obtained from the detector 26. (Δxn, Δyn) and sends a control signal to the shape measurement section 4 to eliminate the corresponding position coordinate error.

That is, the measurement control unit 15 controls the position coordinate 1 error (Δ
A control signal corresponding to the correction "i" corresponding to XntΔyn) is sent to the drive control units 16a and L6b to drive each servo motor, and the positions of the Y-axis and the Y-axis are adjusted to the correct position with respect to the propeller 2. Correct it so that

In this case, as a control signal, the result of adding or subtracting a correction value to the target signal amount may be given as a new [1 target signal to each drive control ff1N6a, 16b, or the target signal may be sent and Y After the positioning of the Y-axis and the Y-axis is completed, control brackets for correction may be independently given.

This position correction corrects the Y-axis and Y-axis positions of the shape measuring section 4, and positions the touch sensor 12 at the correct position.

By the way, the correction control of the position coordinates is performed after the positioning of the Bonon Yona 5 is completed, but this is not after or before the completion of the positioning between the Y-axis and the Y-axis. Good too.

In this way, the rotation angle of the positioner 5 is detected by the detector 26 to obtain the actual rotation angle ((7n-ΔOn), which is fed back to the measurement control unit 15, and the total d]11 control is performed. The measurement control section 15 calculates the deviation amount ΔXn+Δyn of the measurement point using calculation formulas (1) and (2).The measurement control section 15 then uses the signal amount corresponding to the calculated value as the positioning correction amount of the shape measurement section 4. It is output from the control processor processing etc.

By performing the position correction IE in this manner, the pod 3 of the propeller 2 of the object to be measured and the evening/notch sensor 12 are captured in a +F, I, positive positional relationship, making it possible to measure the shape more accurately.

Here, assuming that the resolution of the detector 26 is high precision of about 218 to 220, in this case, about 5 to 1
．． It can be detected for up to 2 seconds, and if R=200Q mm, the resolution is about 50 to 12μ.

As explained above, in the embodiment, the encoder is directly coupled to the rotation axis of the positioner to detect the rotation angle of the object to be measured. Alternatively, the detector may be indirectly coupled to the rotation shaft of the positioner through means such as a roller with little engagement loss.

Furthermore, other detectors that directly detect the rotation angle from the fixed object 11111 may be used.

In addition, in the measurement control unit explained in the embodiment, the correction amount is directly calculated from the Ig + target angle value from the target position control means and the actual angle from the detector, but this is due to the positioning angle error of the positioner. It is also possible to calculate −r1 and calculate the corresponding correction 1, generate it in a function generator, or generate it in a memory table or the like as l jj (j L).

In the embodiment, a microprocessor is built into the measurement control unit to calculate the amount of angular deviation and correction Fit, but this calculation is not limited to the microprocessor (for example, function generation The calculation may be performed using a device, etc., and the generation of the corresponding angle deviation iit or correction amount by a function generator is included in the concept of calculation here.

Furthermore, the shape 31 measuring device in the example is XIY, 2
A three-dimensional measuring device with three axes is used as an example, but this is a three-dimensional measuring device. The correction may be made in at least one direction within a plane parallel to the rotation plane (rotary table) of the positioner that rotates the constant object, and this may be
The invention is not limited to three-dimensional measuring devices. That is,
It may also be a two-dimensional or --dimensional measuring device that performs measurements in the above-mentioned directions.

Further, although a touch sensor is provided on the measurement head as a sensor, it goes without saying that other sensors may be used.

[Effects of the Invention] As can be understood from the explanation in I- below, in the present invention, the measuring head is moved by controlling a moving mechanism that moves the measuring head in at least one direction in a plane parallel to the rotary table. The control unit includes a control unit that controls moving the rotary table in one direction and setting the rotary table to an 11-point rotation position, and a detector that detects the rotation angle of the object to be measured. Since the control is performed to correct the position of the measuring head by calculating the correction value for the positional deviation of the measuring head in one direction based on the detection signal and the information on the target rotational position, the accuracy of the rotational positioning of the object to be measured is improved. It is possible to economically measure the shape with a high degree of γIIj corresponding to the accuracy of the measurement unit without being affected.

4. @l' explanation of the drawings Figure 1 is a block diagram centered on positioner (0 axis) control in a shape measuring device according to an embodiment of the present invention, and Figure 2 is a block diagram of the shape measuring device according to an embodiment of the present invention. Overall configuration diagram,
Fig. 3 is a block diagram of the Y-axis control, Fig. 4 is an explanatory diagram of measurement points of the object to be measured, and Fig. 5 is a block diagram centered on positioner control in a conventional shape measuring device. .

1... Shape measuring device, 2... Propeller (object to be measured)
3... Wing, 4... Shape measurement unit, 5... Positioner, 6... Bed, 7... Base, 7a... Linear scale, 8... Travel frame, 8a... Scale sensor, 9... Column, 9a... Linear scale, 10... Saddle, 10a... Scale sensor,
10b... Scale sensor, 10C... Nando, 1
1... Arm, 12... Touch sensor, 13.14
...Servo motor, 15...Measurement control section, lea,
18b, 16c, 23..." Drive control unit, 18... Feedback signal line, 19... Gear, 20... Pinion, 21... Servo motor, 22... Detector, 2
5... Feed bank signal line, 26... Detector, 2
7... Feedback signal line, 28... Control unit.

Claims (2)

[Claims] (1) A rotary table on which the object to be measured is placed and rotated;
A shape measuring device comprising a measuring head that approaches or contacts the object to be measured, and a moving mechanism that moves the measuring head in at least one direction in a plane parallel to the rotary table, wherein the moving mechanism is controlled to a control unit that controls moving the measurement head in the one direction and setting the rotary table to a target rotation position; and a detector that detects the rotation angle of the object to be measured; A shape characterized in that control is performed to correct the position of the measuring head by calculating a correction amount for a positional deviation of the measuring head in the one direction based on a detection signal from a detector and information on the target rotational position. Measuring device. (2) The moving mechanism is a mechanism for moving the measurement head in at least two directions in a plane parallel to the rotary table, the detector is an encoder that engages with the rotation axis of the rotary table, and the control unit 2. The shape measuring device according to claim 1, wherein the shape measuring device calculates a correction amount for a positional deviation of the measuring head in two directions, and corrects the position of the measuring head in the two directions.