JPH0613965B2 - Three-dimensional measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improved technique of a three-dimensional measuring device that measures, for example, the shape and assembly dimensions of a vehicle body or the like.

[Conventional technology]

At the inspection stage in the vehicle manufacturing process, for example, a three-dimensional measuring device as shown in FIG. 5 is used.

The outline of this apparatus will be described. After the vehicle body 1 as the object to be measured, which has been assembled in a predetermined manner, is set on the surface plate 2, it is composed of a moving body 4 and an arm 5 which move respectively on the base 3 and the column 4a. With a measuring mechanism having an axial degree of freedom, the tracing stylus 6 attached to the tip of the arm 5 is moved to preset measurement points of the vehicle body 1, and the base 3, moving body 4 and arm for each of these measurement points are moved. The movement amount of 5 is detected.

Then, each of these movement amounts is input as a measurement value to the operation unit 7 having a built-in data processing device, and the data processing device compares the input measurement value with a preset reference value of the measurement point. Then, the dimensional error between the two is obtained, and the obtained dimensional error is displayed numerically on the display 8 together with the code indicating the measurement point. (For example, a similar one to Japanese Utility Model Laid-Open No. 58-99614 is disclosed.) [Problems to be Solved by the Invention] However, in such a conventional three-dimensional measuring device, Since the error for each axis is simply calculated from the reference value which is the corresponding triaxial drawing coordinate value and the measured value, there are the following problems.

For example, in FIG. 5, when the vehicle body 1 is measured, the probe 6 is attached to the vehicle body 1 such as a reference point 1-I of the entire vehicle body.
, And the count value of each axis counter circuit described later is set to the corresponding drawing coordinate value, and then each measurement point is measured to evaluate the quality of the vehicle body 1. In the quality evaluation, the quality of the vehicle body 1 is measured. In order to determine whether the component parts 1A, 1B, 1C have poor assembly accuracy or the part precision before assembly, the reference point is changed to the reference point 1-II of the part 1A, for example. Therefore, it is necessary to evaluate the quality by re-measuring each measurement point.

As described above, in the conventional apparatus, in order to evaluate the quality of the vehicle body 1, it is necessary to always perform the measurement several times, and there is a problem that the man-hours are extra.

The present invention is intended to solve such a problem.

[Means for solving problems]

Therefore, as shown in FIG. 1, the three-dimensional measuring apparatus according to the present invention moves a probe having three-axis degrees of freedom onto an object to be measured placed on a surface plate to measure its shape and dimensions. In the three-dimensional measuring apparatus 100 configured as described above, the coordinate values of the triaxial drawing corresponding to each predetermined measurement point on the measured object and the component-specific coordinate conversion coefficient corresponding to the component on the measured object where each measurement point exists Based on the storage means 101 storing the measurement values, the measurement value at the measurement point where the probe is moved, and the triaxial drawing coordinate value stored in the storage means 101 corresponding to the measurement point, the design dimension for each measurement point. And a measurement value when the probe is moved to a predetermined component measurement reference point of the component, triaxial drawing coordinate values of the component measurement reference point,
And a second calculation means 103 for calculating a coordinate conversion coefficient relating to the measurement reference of the part based on the part-specific coordinate conversion coefficient stored in the storage means 101 corresponding to the part, and a measurement in which the probe is moved. Third calculation means 104 for performing coordinate conversion on the basis of the coordinate conversion coefficient calculated by the second calculation means 103 for the measured value at the point, and the third calculation means 1.
The fourth calculation means 105 is provided for calculating an error with respect to the design dimension of each component based on the measurement value coordinate-converted by 04 and the corresponding triaxial drawing coordinate value stored in the storage means 101. .

〔Example〕

Embodiments of the present invention will be described below with reference to FIG. 2 and subsequent drawings.

FIG. 2 is a perspective view showing the outline of the mechanical portion of the coordinate measuring apparatus according to the present invention, and the portions corresponding to those in FIG. 5 are designated by the same reference numerals.

In the figure, a base 3 is mounted on a surface plate 2 on which a vehicle body 1 is mounted.
Is mounted so as to be movable in the Y-axis direction of the measurement coordinate system (orthogonal coordinate system), and a column 4a is erected on this base 3 in the Z-axis direction of the measurement coordinate system.

A moving body 4 is attached to the column 4a so as to be movable up and down, and an arm 5 having a probe 6 attached to its tip is attached to the moving body 4 so as to be movable in the X-axis direction of the measurement coordinate system.

The movement of the base 3 is monitored by a Y-axis pulse generator 11 (FIG. 3) including a Y-axis photo pickup 9 attached to the base 3 and a Y-axis digital scale 10 attached to the surface plate 2. The movement of the mobile unit 4 is
Monitoring is performed by a Z-axis pulse generator 14 (FIG. 3) including a Z-axis photo pickup 12 attached to the moving body 4 and a Z-axis digital scale 13 attached to the column 4a.

The movement of the arm 5 is monitored by an X-axis pulse generator 17 (FIG. 3) including an X-axis photo pickup 15 attached to the moving body 4 and an X-axis digital scale 16 attached to the arm 5. It is like this.

Therefore, these pulse signals from the X, Y, and Z axis pulse generators 17, 11, and 14 are respectively supplied by the counter circuits 180 to 182 in FIG. By counting up or down according to the moving direction of the arm 5, the base 3, and the moving body 4 with reference to the origin or the reference position of the measuring coordinate system, the moving amount of each contact of the probe 6 can be measured. It becomes possible to do so, and by doing so, the tracing stylus 6 is attached to each predetermined measurement point on the vehicle body 1, for example, 1a to 1
It is possible to measure the dimensions (three-axis coordinate values in the measurement coordinate system) of those measurement points when moved to f.

It should be noted that the display 8 for displaying measured values and dimensional errors described later.
Are attached to the moving body 4.

FIG. 3 is a block diagram showing the configuration of the operation unit 7.

The operation unit 7 is composed of a triaxial coordinate value detection unit 18, a keyboard 19, a start command button 20, a data processing microcomputer 21, a data storage device 22, and the like.

The triaxial coordinate value detection unit 18 includes X, Y, and Z axis counter circuits 180 to 182, decoders 183 to 185, and a gate circuit 186, and operates as follows.

That is, the counter circuits 180 to 182 for the X, Y, and Z axes.
Are reset to "0" by turning on the reset key on the keyboard 19 when the origin is set, and similarly, when the designated coordinate value is set, the coordinate value is set by the character key and the ten-key on the keyboard 19, respectively.
The pulse signals Px, Py, Pz accompanying the movement of the arm 5, the base 3, and the moving body 4 from the Y, Z axis pulse generators 17, 11, 14 are counted up or down according to the respective movement directions, The count values Nx, Ny, Nz corresponding to the movement amount of the probe 6 for each axis are output.

Then, the decoders 183 to 185 cause the count values Nx, Ny, and Nz from the X, Y, and Z axis counter circuits 180 to 182.
By inputting these count values to coordinate values (measurement values) [X], [Y], in the measurement coordinate system in which the probe 6 is located.
It is designed to be converted into [Z], and these coordinate values indicate the size of the measurement point.

The coordinate values [x], [y], and [z] converted by the decoders 183 to 185 are input to the display device 8 and displayed, and at the same time, output to the gate circuit 186 so that the gate circuit 186 can When the start command button 20 is opened by being turned on, it is input to the microcomputer 21.

The keyboard 19 is a reset reset key for the X, Y, and Z axis counter circuits 180 to 182 described above, a three-axis drawing coordinate value, a part identification symbol, and a part for storing a command coordinate value setting and a data storage device 22 described later. Equipped with a character key for setting the drawing coordinate value of the reference point and the identification symbol of the conversion target part, a numeric keypad, and an end key that is turned on at the end of measurement (a combination operation of character keys may be used instead) is doing.

The start command button 20 is used for the gate circuit 1 of the triaxial coordinate detection unit 18.
The coordinate values [x], [y], which are output when 86 is opened,
This is a push button switch that is turned on when [z] is temporarily stored in a data memory in the microcomputer 21 and execution of data processing is prompted.

The data processing microcomputer 21 includes a central processing unit (CPU) 210 and a program memory (ROM) 21.
1, a data memory (RAM) 212, an input interface 213, an output interface 214, etc., and outputs a coordinate value from the triaxial coordinate detection unit 18, key operation data from the keyboard 19, and an ON command for the start command button 20. The CPU 210 executes various programs, which will be described later, stored in the ROM 211 in advance to perform processing, display the processing results on the display 8, and display the result on a peripheral device such as a data typewriter, CRT, or XY plotter (not shown). Output.

The data storage device 22 is connected to the bus line of the microcomputer 21 and is assigned an address defined on the microcomputer 21 side.
10 are directly accessible.

Then, in the data storage device 22, the designed triaxial drawing coordinate value of each predetermined measurement point on the vehicle body 1 as the object to be measured, and the part identification of the part before assembly in which each measurement point exists. The component-specific coordinate conversion coefficient and the like corresponding to the component indicated by the symbol and its partial identification symbol are stored.

That is, for example, as shown in FIG.
The triaxial drawing coordinate values and the component identification symbols of the measurement points 1a to 1f of A and 1B are stored in the following form.

iDa xa ya za PA iDb xb yb zb PA iDc xc yc zc PA iDd xd yd zd PB iDex xye ze PB iDf xf yf zf Pd] [identification, [identification] [where x is yf zf]]
Is a triaxial drawing coordinate value, and [P] is a part identification symbol.

Regarding the component-specific coordinate conversion coefficient, the components 1A, 1
Required coefficient data corresponding to each of B and the component 1C is stored for each component group.

Hereinafter, with reference to the flow chart of FIG. 4, the usage and operation of the three-dimensional measuring apparatus according to the present invention will be described step by step.

When the power of the operation unit 7 is turned on, the CPU 210 of the microcomputer 21 performs a predetermined initialization process (not shown) and then proceeds to STEP 1 shown in FIG. 4 to wait for the activation command button 20 to be turned on.

Next, the measurer moves the tracing stylus 6 shown in FIG. 2 to the measurement reference point 1-I of the vehicle body 1 as the object to be measured, and then uses the ten keys and the letter keys on the keyboard 19 of the operation unit 7 to measure the measurement reference. By inputting drawing coordinate values of point 1-point I, X in the triaxial coordinate detection unit 18 of the operation unit 7,
Count values Nx, Ny of the counter circuits 180 to 182 for Y and Z axes,
Set Nz to the drawing coordinate value of measurement reference point 1-I.

Next, when the measurer moves the probe 6 of FIG. 2 to, for example, the component measurement reference point 1-II of the component 1A, and then turns on the start instruction button 20 in the operation unit 7, the on instruction is the microcomputer. 21 input interfaces 2
Of the component measurement reference point 1-II output from the decoders 183 to 185 of the triaxial coordinate detection unit 18 at the time of reaching the component measurement reference point 1-II of the component 1A of the tracing stylus 6. The coordinate values [x], [y], and [z] in the measurement coordinate system of the tracing stylus 6 indicating the dimensions pass through the gate circuit 186 and are also input to the input interface 213, so that the CPU 210 of FIG. Go from STEP1 to STEP2,
The input measurement coordinate values are stored in the component measurement reference point coordinate value storage area in the RAM 212 as [x], [y], and [z].

Then, the character keys and numeric keys in the keyboard 19 of the operation unit 7, part drawing coordinates of reference point 1-II [x _2], [y _2], [z _2] and component identification symbol [P
When [A] is input, the CPU 210 proceeds from STEP 2 to STEP 3, and the drawing coordinate values [x ₂ ], [y ₂ ], [z ₂ ] and the part identification code (PA) of the input part measurement reference point 1-II are input. Is stored in the component measurement reference point drawing coordinate value storage area and the component identification symbol storage area in the RAM 212.

Then, the CPU 210 proceeds from STEP3 to STEP4 and obtains the origin movement component of the coordinate conversion coefficient according to the following equation (corresponding to the second computing means 103).

However, [x ₁ , y ₁ , z ₁ ] is the measurement coordinate value of the part measurement reference point [x ₂ , y ₂ , z ₂ ] is the drawing coordinate value of the part measurement reference point [x ₃ , y ₃ , Z ₃ ] is the origin movement component of the coordinate conversion coefficient related to the measurement standard of the part. Then, the obtained coordinate conversion coefficient (including the rotational movement component) is stored in the coordinate conversion coefficient storage area in the RAM 212 in STEP5.

The component-specific coordinate conversion coefficient (rotational movement component) is stored in the data storage device 22 in advance and is searched by the component identification symbol “PA”.

Next, the CPU 210 proceeds to STEP 6 and restarts the command button 2 again.
Wait for 0 to turn on.

Here, the measurer attaches the measuring element 6 shown in FIG.
When the start command button 20 in the operation unit 7 is turned on after moving to a, the on command is input to the input interface 213 of the microcomputer 21 and the measurement of the contact point 6 is performed as in the case of the reference point. Point 1
Decoder 1 of triaxial coordinate value detection unit 18 at the time of reaching a
Coordinate values (measurement values) [x] in the measurement coordinate system of the tracing stylus 6 indicating the dimensions of the measurement points 1a output from 83 to 185.
[Y] and [z] pass through the gate circuit 186 and are also input to the input interface 213. Therefore, CP
The U210 proceeds from STEP6 to STEP7 in FIG. 4 to temporarily store the input coordinate values [x], [y], [z] in the measurement value storage area in the RAM 212.

The coordinate values stored in the RAM 212 are numerically displayed on the display 8.

When the storage process of STEP7 is completed, the CPU 210 proceeds to STEP8 and searches the data storage device 22 for the drawing coordinate value and the part identification symbol corresponding to the measurement point (in this case, the measurement point 1a).

As a search method, for example, measured value coordinates [x],
[Y], [z] and drawing coordinate values, [x ₀ ], [y ₀ ], [z
₀ ] and a method in which the difference between the measured value and the measured value is a fixed value or less is retrieved as a drawing coordinate value corresponding to the measured value, and a method of reading out in a predetermined measurement order.

Then, the CPU 210 stores the retrieved data in a required data storage area in the temporary RAM 212 in STEP 9, and then in the next STEP 10, RAM 7 in STEP 7 and STEP 8.
Measurement coordinate values stored in the 2 [x], [y], [z], drawings coordinates [x _0], [y _0], [z _0], and part identification symbols [PA] respectively read out, the coordinates Value error Δx = x-
x ₀ , Δy = y−y ₀ , Δz = z−z ₀ are calculated (first
(Corresponding to the calculation means 102).

The CPU 210 temporarily stores the calculated coordinate value errors (errors for each axis) Δx, Δy, Δz in the error data storage area in the RAM 212 in STEP 11, and then the next STEP 12
Then, the coordinate value errors Δx, Δy, and Δz obtained by calculation are displayed on the display 8 as numerical values.

Next, the CPU 210 proceeds to STEP13 and RAM2 in STEP3.
The component identification code stored in 12 is read, and it is determined whether or not it matches the component identification symbol read in STEP 10. If they match, the process proceeds to STEP 14, otherwise, the process proceeds to ST.
Proceed to EP7.

In STEP14, the coordinate conversion coefficient stored in RAM212 in STEP5 and STEP7 And the measured coordinate values [x], [y], and [z] are read out, and the coordinate conversion calculation of the measured coordinate values (corresponding to the third calculating means 104) is performed as follows.

Further, in STEP 8, the drawing coordinate values [x ₀ ], [y ₀ ] and [z ₀ ] stored in the RAM 212 are read out, and there is an error between the converted measured values [x ₃ ], [y ₃ ] and [z ₃ ]. Calculations (corresponding to the fourth calculation means 105) Δx ′ = x ₃ −x ₀ , Δy ′ = y ₃ −y ₀ , Δz ′ = z ₃ −z ₀ are performed.

Then, the CPU 210 causes the calculated conversion value error Δ
After temporarily storing x ′, Δy ′, and Δz ′ in the conversion value error data storage area in the RAM 212 in STEP 15, the next ST
Proceed to EP16 and calculate the converted value error Δx ′, Δ
Numerical values are displayed on the display 8 for y'and Δz '.

In the next STEP 17, if the end key on the keyboard 19 is turned on and the measurement is completed, the process is ended, otherwise, the process returns to STEP 6 and waits for the start command button 20 to be turned on again.

In this way, the measurer can measure the measurement points 1b and 1 in FIG.
By repeating the above-described measurement work for each of c and 1d, the coordinate value error Δx, Δy, Δz as the dimension error with respect to the design dimension of each measurement point 1b, 1c, 1d, and the coordinate based on the measurement standard of the designated component. Converted value and converted value error Δx ', Δy', Δ as dimension error for design dimension
z'can be measured.

〔The invention's effect〕

As described above, according to the present invention, a probe having three-axis degrees of freedom is moved onto an object to be measured placed on a surface plate to measure its shape and dimensions. In the measuring device, storage means for storing triaxial drawing coordinate values corresponding to respective predetermined measurement points on the object to be measured and component-specific coordinate conversion coefficients corresponding to parts on the object to be measured where the respective measurement points exist. And an error with respect to the design dimension at each measurement point, based on the measurement value at the measurement point where the probe is moved and the triaxial drawing coordinate value stored in the storage means corresponding to the measurement point. First calculation means, a measurement value when the probe is moved to a predetermined component measurement reference point of the component, triaxial drawing coordinate values of the component measurement reference point, and the storage corresponding to the component. The parts stored in the means Second calculation means for calculating the coordinate conversion coefficient related to the measurement reference of the component based on the coordinate conversion coefficient, and the measurement value at the measurement point to which the probe is moved were calculated by the second calculation means. Based on the third calculation means for coordinate conversion based on the coordinate conversion coefficient, the measured value coordinate-converted by the third calculation means, and the corresponding triaxial drawing coordinate value stored in the storage means, respectively. Since the fourth calculating means for calculating the error with respect to the design dimension of the component is provided, it is possible to perform the measurement work involving the change of the reference point several times for each measurement point unlike the conventional case.
It becomes possible to simultaneously obtain a dimensional error with respect to the design dimension at each measurement point of the object to be measured and a dimensional error with respect to the design dimension of each of the parts constituting the object to be measured at one measurement.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a perspective view showing the outline of the mechanical portion of the coordinate measuring apparatus according to the present invention, and FIG. 3 is a block showing the configuration of the operating unit 7 of FIG. FIG. 4 is a flow chart of a processing program executed by the CPU 210 of FIG. 3, and FIG. 5 is a perspective view showing a conventional example of a three-dimensional measuring apparatus. 1 ... vehicle body (object to be measured), 2 ... surface plate, 3 ... base, 4 ...
Moving body, 4a ... column, 5 ... arm, 6 ... measuring element, 7 ...
Operation unit, 8 ... Display device 11 ... Y-axis pulse generator 14 ... Z-axis pulse generator 17 ... Z-axis pulse generator 19 ... Keyboard, 20 ... Startup command button 21 ... Microcomputer 22 ... Data storage device

Claims (1)

[Claims] 1. A three-dimensional measuring device in which a probe having three-axis degrees of freedom is moved onto an object to be measured placed on a surface plate to measure its shape and dimensions. In the storage means for storing the triaxial drawing coordinate values corresponding to each predetermined measurement point in and the component-specific coordinate conversion coefficient corresponding to the component in the measured object where each measurement point exists, and moving the tracing stylus. First calculation means for calculating an error with respect to the design dimension for each measurement point based on the measurement value at the measurement point and the triaxial drawing coordinate value stored in the storage means corresponding to the measurement point, Measured values when the probe is moved to a predetermined part measurement reference point of the part, triaxial drawing coordinate values of the part measurement reference point, and part-specific coordinate conversion stored in the storage means corresponding to the part Based on the coefficient and Second calculation means for calculating a coordinate conversion coefficient related to the measurement standard of the component, and coordinate conversion based on the coordinate conversion coefficient calculated by the second calculation means for the measurement value at the measurement point to which the probe is moved. Based on the third calculation means, the measured values coordinate-converted by the third calculation means, and the corresponding triaxial drawing coordinate values stored in the storage means corresponding thereto, an error with respect to the design dimension of each component is calculated. A three-dimensional measuring device, characterized in that it is provided with a fourth computing means for computing.