JPH05253795A - Alignment adjusting method for non-circular shaped work in cylindrical coordinate type three-dimensional measuring device - Google Patents

Abstract

PURPOSE:To provide a method by which aligning adjustment in a cylindrical coordinate type three-dimensional measuring device for a cam shaped work W being hitherto difficult as for aligning adjustment by a coordinate transformation computing process can be performed quickly and surely. CONSTITUTION:The whole form due to the measured point group data obtained by sampling a work W on a rotary table 4 by means of a detector 22, and the whole form due to the ideal form point group data on design input from a keyboard input part 31, are piled up on the same axis of coordinates and displayed as a picture for rough adjustment, the picture and a picture for fine adjustment displaying a form error curve due to difference between the measured point group data and the ideal form data are selectively displayed, and an angle adjusting quantity and/or an eccentricity adjusting quantity which are set by an operator from these displays, are input so as to make the error to a minimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for centering and adjusting a non-round work in a cylindrical coordinate type three-dimensional measuring device such as a perfect circle measuring device.

[0002]

2. Description of the Related Art Conventionally, when a cylindrical workpiece is measured by a cylindrical coordinate type three-dimensional measuring apparatus as shown in FIG. 11, a rotary shaft of a rotary table 101 and the measuring workpiece 10 are used.
It is necessary to match the center axes of the two. In the case of a center-supported work that can use the tailstock 103 indicated by a virtual line, centering is not necessary, but in the case of a chucked work, centering adjustment needs to be performed. In this chucking work centering method, an X / Y biaxial linear movement type cross slide dedicated to centering is provided on the rotary table 101,
A method of actually aligning the center axis of the work with the rotary axis of the rotary table and a method of measuring the work placed on the rotary table with misalignment on polar coordinates (r, θ) and performing coordinate conversion by calculation processing. There is a method in which the same effect as when the work is moved is obtained. The latter method is generally used because the latter method can perform centering only by calculation and can speed up the centering as compared with the former method.

[0003]

The centering adjustment method by the coordinate conversion calculation processing of the prior art calculates the center of the work from the measured point group, so that the difference in radius is measured as in the roundness measurement of a cylindrical work. In the case of small, the minimum error circle is obtained and the center of this circle is used. However, in the case of a work having a large radius difference such as a cam-shaped work, there is a problem that it is difficult to calculate the center. The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a centering adjustment method for a non-perfect circular shape work by coordinate conversion calculation processing. .

[0004]

In order to achieve the above object, the method for centering and adjusting a non-round work in a cylindrical coordinate type three-dimensional apparatus according to the present invention is a rotary table (C).
(Axis) and two orthogonal linear guide axes (X / Z axes), the coordinate conversion is performed after sampling the non-round work on the rotary table at the approximate turning center position to create measurement point group data. In a method of performing a centering adjustment suitable for calculation processing, a rough adjustment screen in which a first overall shape based on the measurement point cloud data and a second overall shape based on previously input ideal shape point cloud data are superimposed and displayed on the same coordinate axis. And a fine adjustment screen displaying a shape curve based on the difference between the measurement point cloud data and the ideal shape point cloud data, and the adjustment set by the operator while looking at the adjustment screen or the fine adjustment screen. The angle is adjusted and the eccentricity is adjusted according to the amount to minimize the error.

[0005]

[Operation] A non-round work is placed on a rotary table, sampling is performed to create measurement point cloud data, and a first overall shape based on this measurement point cloud data and a second based on ideal shape point cloud data for design purposes. Looking at the coarse adjustment screen where the overall shape is displayed in an overlapping manner, the angle adjustment amount and the eccentricity adjustment amount are set respectively, and these are input to perform coordinate conversion to reduce the error. When the error becomes small to some extent in this way, the angle adjustment amount and the eccentricity adjustment amount are set by looking at the screen for fine adjustment of the shape error curve of the difference between the measurement point group data and the ideal shape point group data. , Inputting this and performing coordinate conversion gradually approaches the minimum error.

[0006]

EXAMPLES Examples will be described with reference to FIGS. In the cylindrical coordinate type three-dimensional measuring apparatus of FIGS. 1 and 2, a rotary table 4 is concentrically fixed to the upper end of a vertical center axis 3 of rotation which is rotatably supported by an air bearing 2 on a frame 1. The rotation shaft of the C-axis rotary encoder 5 is concentrically fitted to the lower end of the turning center shaft 3. The rotary table 4 is rotated by a C-axis pulse motor 6 fixed inside the frame via a belt 7, and an evaluation cam-shaped work W is placed on the rotary table 4 via a table 8. A column 9 is erected on the rear side of the frame body 1, and a guide 1 in the Z-axis direction is provided on the front surface of the column 9.
A saddle 12 is provided so as to be movable along 1. The saddle 12 is moved and positioned via the ball screw 13 by the Z-axis pulse motor 14 fixed to the column 9, and the guide 1
The position is detected by the Z-axis linear encoder 15 provided in parallel with 1.

A guide 16 in the X-axis direction is provided on the front surface of the saddle 12.
Is provided, and a slider 17 is provided so as to be movable along the guide 16. The slider 17 is moved and positioned by an X-axis pulse motor 18 fixed to the saddle 12 via an X-axis ball screw 19, and is provided in parallel with the guide 16 so that position detection is performed by an X-axis linear encoder 21. A differential transformer type displacement type (electric micro) is used as the detector 22 attached to the slider 17, and detects a linear minute displacement in the X-axis direction separately from the X-axis movement of the slider 17. Further, a computing personal computer 23 is installed near the frame 1.

FIG. 3 is a block diagram of a control system including a configuration diagram of a partial three-dimensional measuring device. The control device 24 on the side of the three-dimensional measuring device has a C for driving the C-axis pulse motor 6.
Axis driver 25, detector interface 26 for passing output signals of detector 22, X-axis driver 27 for driving X-axis pulse motor 18, X-axis linear encoder 21
The X-axis linear encoder interface 28 for delivering the output signal of the C-axis rotary encoder 5 and the C-axis rotary encoder interface 29 for delivering the output signal of the C-axis rotary encoder 5 are respectively incorporated. The control input personal computer 23 has a keyboard input section 3 for inputting commands and information.
1, a calculation processing unit 32 that performs each calculation described below, a calculation result display unit 33 that displays a calculation result, etc., and a control processing unit 34 that controls signals between the control device 24 and the calculation processing unit 32, respectively. ..

Next, the operation of this embodiment will be described.
First, the sampling procedure of the cam-shaped work W will be described with reference to the flowchart of FIG. In step S1, a rotary table rotation command is issued to cause the rotary table 4 to rotate by a unit angle (1 °), and the C-axis rotary encoder 5 detects the rotation angle. In step S2, it is confirmed whether or not it is within the detection range (± 0.2 mm) of the electric micro (detector) 22, and in the case of NO, it is confirmed again in step S3 that it is far (NO) (near).
In this case, in step S4, the X-axis reference amount (0.36 m
If the answer is YES, the slider 17 is moved closer by the X-axis reference amount so as to be within the measuring range of the detector in step S5. If YES in step S2, steps S3 to S5 are skipped.

Next, in step S6, the value of the electric micro 22 is read into the control processing section 34 via the detector interface 26, and in step S7, the value of the X-axis linear encoder 21 is read into the control processing section 34 via the interface 28. Read. In step S8, the arithmetic processing unit 32 calculates the sum of the value of the electric micro 22 and the X-axis linear encoder 21 to calculate the detection point center X coordinate. Next, in step S9, the value of the rotary encoder 5, that is, the rotation angle of the work table 4 is read, and step S1
At 0, the value of the point cloud (X, C) is registered. Step S
In 11, it is confirmed whether or not one rotation (180 °) has been completed. If NO, the process returns to step S1, and if YES, the sampling ends.

Next, referring to FIG.
It will be described in accordance with the flowchart of. In step S12, it is confirmed whether or not the input command from the keyboard input unit 31 is the rough adjustment screen, and if YES, the screen of the ideal shape point group is output based on the ideal shape data input in advance in step S13. In step S14, the screen of the measurement point group is output based on the measurement data obtained by the above-described sampling, and the ideal shape and the measured shape are superposed on the same XY coordinate axis line as shown in FIG. 6 on the CRT screen, for example. indicate. Then, the operator looks at this screen display and determines in step S15 whether or not to adjust the angle.
In the case of S, in step S16, as shown in FIG. 7, focusing on only the phase shift among the centering errors of the ideal shape and the actually measured shape, the mounting error angle θc is registered, and it is considered that it is close to this. The angle adjustment amount is input from the keyboard input unit 31. In step S17, the input angle adjustment amount is added to the table turning angle θi in the arithmetic processing unit 32, and the centering angle error is reduced by this arithmetic processing. If NO in step S15, steps S16 and S17 are skipped.

Next, in step S18, it is judged whether or not the eccentricity is adjusted. If YES, in step S19, as shown in FIG. 8, focusing only on the eccentricity error among the centering errors, the misalignment amount εX, With the register of εY, the adjustment amounts εX ′ and εY ′ are input. Next, in step S20, the first measurement point group coordinate conversion is performed to convert the polar coordinates r, θ into X, Y coordinates. Then, the measurement point group is translated by the adjustment amounts εX ′ and εY ′ input to the point groups Xi and Yi of the X and Y coordinates. However, Xi 'and Yi' are X after translation
Y coordinate value.

Next, in step S22, the second measurement point group coordinate bearing conversion is performed, and the coordinate axis Xi after the parallel movement is performed.
′, Yi ′ is returned to polar coordinates (r, θ) by the following equation: ri = √ (Xi ′ ² + Yi ′ ² ) θi = tan ⁻¹ (Yi ′ / Xi ′). However, if the number of point groups in polar coordinates is n, then 1 ≦ i <n. If NO at step S18, the process between steps S9 and S22 is skipped.

In step S23, it is confirmed whether or not the error is minimum. If YES, the process ends. On the other hand, in the case of NO, the process returns to step S12, and it is confirmed again whether the rough adjustment screen is required. If the fine adjustment screen is desired, the answer is NO, and in step S24, the difference between the input ideal shape data and the actually measured shape obtained by scanning, that is, the error between the ideal value and the actually measured value is calculated, and in step S25, This error is displayed as a shape error curve as shown in FIG. Next, in step S15, the operator looks at this display and determines whether the angle adjustment is necessary, and thereafter, the same adjustment as described above is performed, and the adjustment is repeatedly performed until the error is confirmed to be minimum in step S23.

[0015]

Since the present invention is configured as described above, it has the following effects. The coarse adjustment screen and the fine adjustment screen are selected and displayed, the adjustment amount is set and entered while looking at the screen, and the angle adjustment and the eccentricity adjustment are performed respectively. Can be implemented quickly and reliably. When measuring workpieces continuously,
The work centering error can be adjusted in parallel during the next work measurement, improving the efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of a cylindrical coordinate type three-dimensional measuring apparatus of this embodiment.

FIG. 2 is a structural diagram of a cylindrical coordinate type three-dimensional measuring device.

FIG. 3 is a block diagram of a control system including a configuration diagram of a partial measuring device.

FIG. 4 is a flow chart for explaining the sampling operation of the present embodiment.

FIG. 5 is a flow chart for explaining the centering adjustment operation of the present embodiment.

FIG. 6 is an explanatory diagram showing an example of a rough adjustment screen in which an actually measured shape and an ideal shape are displayed in an overlapping manner.

FIG. 7 is an assumed diagram focusing only on an angular error of the errors between the actually measured shape and the ideal shape.

FIG. 8 is an assumed diagram focusing only on an eccentricity error of an error between a measured shape and an ideal shape.

FIG. 9 is an explanatory diagram of parallel movement of X and Y coordinate values depending on an input adjustment amount when adjusting an eccentricity error.

FIG. 10 is an explanatory diagram showing an example of a fine adjustment screen displaying an error.

FIG. 11 is a perspective view of a conventional cylindrical coordinate type three-dimensional measuring device.

[Explanation of sign]

4 rotary table 5 rotary encoder 6 C-axis pulse motor 17 slider 18 X-axis pulse motor 22 detector 23 computing PC 24 controller W cam shape work

Claims (1)

[Claims] 1. A non-round work which is approximately at the center of turning on the rotary table of a three-dimensional measuring device comprising a rotary table (C axis) and two orthogonal linear guide axes (X and Z axes) is sampled and measured. In the method of performing centering adjustment by coordinate conversion calculation processing after creating the point cloud data, the first overall shape based on the measurement point group data and the second overall shape based on the ideal shape point group data previously input are placed on the same coordinate axis. The coarse adjustment screen displayed in an overlapping manner and the fine adjustment screen displaying the shape error curve due to the difference between the measurement point cloud data and the ideal shape point cloud data are selectively displayed, and the operator displays the coarse adjustment screen or A non-round work center in a cylindrical coordinate type three-dimensional measuring device characterized by performing an angle adjustment and an eccentricity adjustment according to an adjustment amount set while looking at a fine adjustment screen to minimize an error. Adjusting method.