JP3373880B2 - How to measure assembly accuracy - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembling accuracy measuring method for measuring the consistency of building members and the like.

[0002]

2. Description of the Related Art For example, in an automobile manufacturing plant, in order to assemble building members such as a front hood, a trunk lid, a front door, and a rear door to a vehicle body, a front fender, a rear quarter, Maintains proper assembly accuracy for the surface difference that is the gap between the body parts such as the rear skirt and the level difference between the mutual members, and between the adjacent building members such as the front and rear doors. It is desired to improve the quality and aesthetics of the vehicle body and reduce the number of man-hours for correction in the post process.

Therefore, after mounting members such as a front hood and a trunk lid are attached to the vehicle body, the division and surface difference between these adjacent members are extracted by a worker using a measuring instrument such as a taper gauge or a caliper. Measurements are being made.

On the other hand, as shown in FIG. 9 disclosed in Japanese Patent Laid-Open No. 61-98683 and showing a plan view of the essential parts of FIGS. 8 and 8, a door supported by a door assembling device is provided. A door assembling method in which the door assembling device is positioned at a door opening of a vehicle body based on a positioning operation of a door assembling apparatus and is automatically assembled, wherein an accent line 21 on a door 20 side and an accent line 23 on a vehicle body 22 side are provided. In the continuous portion of the door, the sensor 25 provided in the door assembling device 24 detects the vertical shift between the two and the door 2 supported by the door assembling device 24 based on the sensor output.
Correct the direction of 0 and accent line 21 on the door 20 side
There has been proposed a vehicle door assembling method for aligning the accent line 23 on the vehicle body 22 side with the vehicle body 22 side by side.

Further, as shown in Japanese Patent Application Laid-Open No. 4-76409, a measuring object is irradiated with a light beam while scanning in a predetermined direction, the reflected light from the object is received, and based on the information on the reflected light. A step detection method for detecting a step has been developed.

[0006]

In the measurement by the worker using the above-mentioned measuring instrument, the measurement work in which the worker individually measures the surface difference between adjacent members such as various building members is required. It is cumbersome and requires a huge number of man-hours to measure over all manufactured products, and must rely on unannounced measurements, and there is a risk of damage to parts due to contact with the measuring instrument. There are problems such as.

Further, in the method of assembling an automobile door disclosed in Japanese Patent Laid-Open No. 61-98683, a sensor detects a vertical shift of each accent line between the door and the vehicle body to detect the door. Since the orientation of the door is corrected, the shapes of the door and the vehicle body are limited, and it is difficult to apply the same to the front hood and the trunk lid. Further, since the sensor comes into contact with the vehicle body, the vehicle body may be damaged and the quality may be deteriorated.

Further, in the step detecting method disclosed in Japanese Patent Laid-Open No. 4-76409, an object is irradiated with a light beam, reflected light from the object is received, and the step is detected based on the information. The step of the object can be detected by non-contact, and the step can be measured without inducing the occurrence of scratches. However, there is a problem such that it is difficult to obtain a highly accurate measurement result when there is a gap between the members to be measured, that is, there is a gap between adjacent members, and especially when the member has a curved surface.

Therefore, an object of the present invention is to efficiently measure a surface difference between adjacent members such as a main body member, a building member, and adjacent building members, and to limit the shape of the members. It is an object of the present invention to provide a method for measuring the assembling accuracy that can obtain a high-quality product without the risk of scratches.

[0010]

In order to achieve the above object, a method of measuring the assembling accuracy according to the present invention is to irradiate the matching points of adjacent members to be measured with a one-dimensional laser beam in a transverse direction, In an assembling accuracy measuring method in which a CCD camera detects a point on both members as a reference point and a surface difference between the two members is calculated based on the detection signal, a method for measuring a laser beam irradiation on one member is performed. One reference point and other reference points on the member existing between these reference points are used to obtain the center of the approximate circle and the radius of the approximate circle having an arc of a point sequence formed on the member, and to irradiate the laser beam on the other member. The distance between the reference point and the center of the approximate circle is obtained, and the difference between this distance and the radius is used as the surface difference between the two members.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an assembly accuracy measuring method according to the present invention will be described below with reference to the drawings, taking as an example the case where the assembly accuracy of an automobile body is measured.

FIG. 1 is an explanatory perspective view showing a usage state of an assembling accuracy measuring device 11 used for carrying out the assembling accuracy measuring method in the present embodiment, and FIG. 2 is a plan view of the same. 1 is an assembly line for transporting the vehicle body 2. A vehicle body 2 conveyed by the assembly line 1 is a vehicle body body member such as a front fender 4, a rear quarter 5, a rear skirt 6 and the like, which constitutes a vehicle body 3, and a building member such as a front hood 7, a front door 8, a rear door 9, a trunk lid. 1
It has 0 and so on.

An assembling accuracy measuring device 11 is arranged on the side of the assembly line 1 serving as the measuring station I. The assembling accuracy measuring device 11 is separated from the assembly line 1 by the assembly line 1
A pair of guide rails 12 arranged along the guide rails, a robot 13 that reciprocates on the guide rails 12, and a robot 13.
Measuring device 14 provided at the arm tip 13a of the vehicle, assembly specifications such as a vehicle type of the vehicle body 2 that is provided at an appropriate position on the side of the assembly line 1, and is conveyed along the assembly line 1 and a stop position of the vehicle body 2 Reading device 15 for reading an image, reading device 15
The control unit 16 for operating each device according to the detection signal from the robot 1 and the robot 1 according to the signal from the control unit 16
The robot controller 17 which gives a control instruction to 3 is the main constituent device.

The vehicle body 2 conveyed by the assembly line 1 is stopped at the measuring station I in which the assembling accuracy measuring device 11 is installed, and the vehicle body 2 is read by the reading device 15.
The assembly specification and the accurate stop position of the device are detected, and the detection signal is transmitted to the control unit 16. Measurement conditions such as measurement points in each assembly specification are input to the control unit 16 in advance, and the measurement apparatus 14 is installed at the measurement location corresponding to the assembly specification of the vehicle body 2 conveyed based on the detection signal from the reader 15. The robot controller 17 is instructed to move, and the robot controller 17 causes the robot 13 to move along the guide rails 12 and to swing the robot arm.

The points of division and surface differences measured by the measuring device 14 are, for example, hatched front fender 4 and front hood 7, front fender 4 and front door 8, front door 8 and rear door 9, rear door 9 and rear quarter 5, rear quarter. 5 and the trunk lid 10, and the matching points A such as the trunk lid 10 and the rear skirt 6,
B, ... F.

The measuring device 14 provided on the arm tip 13a of the robot 13 has a perspective view as shown in FIG.
The laser light emitter 14a and the CCD camera 14b are provided, and the laser light emitter 14a irradiates a measurement point, for example, a matching point B between the front fender 4 and the front door 8 with a one-dimensional linear laser beam, and the irradiated state. CCD
A division D between the front fender 4 and the front door 8 is provided between the end points on the front fender 4 and the front door 8 where the irradiation is interrupted in the portion read and irradiated by the camera 14b.
Assumed to be A, an arithmetic unit 14c attached to the measuring device 14 or a control unit 16 separately arranged based on the information.
The coordinate of the end point is obtained by calculating the division DA by calculating the numerical data based on the coordinate, and the coordinate of the point on the irradiation separated from the both end points by a predetermined distance, and calculating the numerical data based on this coordinate. Thus, the surface difference between the front fender 4 and the front door 8 is obtained. The suitability of the assembling accuracy of these divided DA and surface difference DB is determined and displayed.

The other matching points A, C ... F are measured by such a measuring method, and the suitability of the assembling accuracy of each division and surface difference is judged and displayed.

Next, the measuring method by the assembling accuracy measuring apparatus thus constructed will be described in detail with reference to the flow chart shown in FIG. 4 and the explanatory views shown in FIGS.

An object to be measured in which a front hood 7, a front door 8, a rear door 9 and a trunk lid 10 which are building members are attached to a vehicle body 3 composed of a front fender 4, a rear quarter 5, a rear skirt 6 and other members. The vehicle body 2 to be described is carried into the measuring station I by the assembly line 1 and stopped at a predetermined position (step 1).

The vehicle body 2 carried into the predetermined position of the measuring station I in step 1 is managed by the reading device 15 according to the instruction of the control unit 16. Information necessary for measurement such as vehicle type, assembly specifications, and accurate stop position is read (step 2), and the detection signal is input to the control unit 16.

The control unit 16 to which the detection signal corresponding to the carried-in vehicle body 2 is input selects a measuring condition corresponding to the vehicle body from various measurement conditions inputted in advance, according to the assembly specification of the vehicle body. Robot 13 to operate
Give instructions to. In response to this instruction, the robot 13 is moved along the guide rail 12 and the arm is swung to move to the alignment point to be measured, for example, the alignment point B by the measuring device 14 provided at the arm tip 13a (step 3), and the alignment point. The divided DA of B and the surface difference DB are measured, and these measurement results are compared with a predetermined reference value to determine the suitability of the measurement results (step 4).

The measurement of the division of the matching point B in step 4 and the determination of suitability will be described with reference to the flow charts shown in FIGS. 5 and 6 which are sectional views taken along line VV of FIG. In the present invention, the laser light emitter 14a is a one-dimensional line extending in the front-rear direction of the vehicle body 2 by the laser light, and has a front fender 4 and a front door 8.
The CCD camera 14b reads the irradiation state, and the control unit 16 performs image processing. In this description, the coordinate system for image processing is defined as Y in the vehicle longitudinal direction.
It is assumed that the axis and the vehicle width direction are the Z axis and the front door 8 projects outward from the front fender 4 by the surface difference DB.

At step a, the interrupted end point of the irradiation line on the front door 8 side is regarded as the front end of the front door 8,
The coordinates are read by the CCD camera and the coordinates (Ya, Za) are obtained with the tip as the division reference point G _1.
By using the divided end point of the irradiation line on the rear end side of the front fender 4 as the division reference point G ₂ , the coordinates (Yb, Zb)
Ask for. Next, in step c, the division reference points G ₁ and G
The difference (Ya-Yb) in the Y coordinate from ₂ is obtained and used as the division DA. This Y coordinate difference (Ya-Yb) is compared with a reference value preset and input in the next step d to determine whether or not it is appropriate and displayed, and the result is stored (step e) and the matching point B is stored. Complete the measurement and determination of the divided DA.

Similarly, the surface difference measurement and suitability determination of the matching point B in step 4 will be described with reference to the flowcharts shown in FIGS. 5 and 7.

First, at step f, since the front end of the front door 8 is bent back, in order to obtain an accurate value, the divided reference point G ₁ excluding this curved portion is separated by a predetermined distance a _{1 in the} Y-axis direction. An irradiation point on the front door 8 is defined as a plane difference reference point Pa ₁ and its coordinates (Ya + a ₁ ,
Za ₁ ) is calculated.

The subsequent set said division criterion G ₁ plane difference reference point Pa ₂ points on a predetermined dimension a ₂ away front door 8 in the Y-axis direction from the front door 8 in step g, the coordinate (Ya + a ₂ , Za ₂ ) and these surface difference reference points Pa
_One point on the front door 8 existing between ₁ and Pa ₂ , for example, a point distant from the division reference G _{1 by} a predetermined dimension a _{3 in the} Y-axis direction is defined as a plane difference base point Pa ₃ and its coordinates (Ya + a ₃ , Za ₃ ) Ask for.

At the next step h, the front fender 4
A point on the front fender 4 which is separated from the dividing reference point G ₂ by a predetermined dimension b _{1 in the} Y-axis direction in order to avoid the bent back portion of the front end is defined as a surface difference reference point Pb ₁ and its coordinates (Yb- b ₁ , Zb ₁ ) is obtained.

In the next step i, the surface difference reference point Pa
₁ , Pa ₂ and Pa ₃ coordinates (Ya + a ₁ , Za ₁ ),
The coordinates (Yc ₁ , Zc ₁ ) of the center O of the approximate circle having the coordinate data string formed by (Ya + a ₂ , Za ₂ ) and (Ya + a ₃ , Za ₃ ) as the arc a and the radius R of this approximate circle
O is obtained, and this arc a is assumed to be the reference surface of the front door 8.

In the subsequent step j, the coordinates (Yc ₁ , Zc ₁ ) of the center O of the approximate circle obtained in step i and the coordinates (Yb-b ₁ , of the surface difference reference point Pb ₁ on the front fender 4).
Zb ₁ ), the distance Rb of the surface difference reference point Pb ₁ on the front fender 4 from the center O of the approximate circle is calculated, and then in the next step k, the radius RO of the approximate circle and the center of the front fender 4 are measured. The surface difference DB is obtained by calculating the difference between the surface difference reference point Pb _{1 and} the distance Rb.

This surface difference DB is compared with the reference value preset and input in the next step l to judge and display the suitability of the surface difference DB, and the result is stored in step m to store the matching point. The measurement and determination of the surface difference DB of B are completed.

In the above description, three points on the laser light irradiation, which are separated by a predetermined distance a ₁ , a ₂ , a ₃ from the division reference point G ₁ of the front door 8 in the Y-axis direction, are plane difference reference points Pa ₁ , Pa _2. ,
As Pa ₃ , these surface difference reference points Pa ₁ , Pa ₂ , Pa
The arc a of the approximate circle determined by ₃ is used as the front door 8
Of was determined plane difference DB front door 8 and the front fender 4 on the assumption that the reference surface, the two surfaces difference reference points Pa ₁ and P
a ₁ and a plurality of points on the front door 8 which are continuously irradiated between the surface difference reference points Pa ₁ and Pa ₂ and are irradiated with laser light, are used as the surface difference reference points, and the respective coordinates are obtained. The approximate circle is obtained by a circle approximation method or the like based on the least squares method based on the coordinate data sequence described above, and the arc a determined by the approximate circle is assumed to be the reference plane of the front door 8 and the coordinates of the center O (Yc ₁ , Zc ₁ ), and
The radius RO is obtained, and the coordinates (Yb-b ₁ , Zb ₁ ) of the surface difference reference point Pb ₁ on the front fender 4 and the coordinates (Yc ₁ , Zc ₁ ) of the center O on the front fender 4 are used. Find the distance Rb to the surface difference reference point Pb ₁ ,
It is also possible to calculate the difference between the radius RO and the distance Rb to obtain the surface difference DB, and in this case, the accuracy can be improved.

By such a method, the assembling accuracy measurement and suitability determination of the division and the surface difference at the preset matching points A to F are executed.

After the division of the matching points A to F and the measurement of the surface difference and the determination of suitability are completed in step 4, the robot 13 is returned to the original state in step 5, and the measurement is completed in step 6. The completed vehicle body 2 is unloaded, and the operation is completed by waiting for the measurement of the next transported vehicle body.

[0034]

As described above, according to the present invention, a surface difference between an arc-shaped reference surface conforming to the curved surface of one adjacent member and the other member can be obtained based on the reference points on the adjacent one member. As a result, it is possible to obtain a highly accurate surface difference that matches the shape, and it is possible to efficiently measure the assembly accuracy of the surface difference between the members at the matching point of the members that are adjacent to each other in the contacted state. In addition to improving the quality, contact scratches that occur on the product can be prevented, and the number of repair steps in the subsequent steps can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory perspective view illustrating an embodiment of an assembly accuracy measuring method and an assembly accuracy measuring apparatus for an automobile body of the present invention.

FIG. 2 is likewise a plan view of FIG.

FIG. 3 is likewise an explanatory view of a main part of the assembling accuracy measuring method and the assembling accuracy measuring device.

FIG. 4 is likewise a flowchart illustrating a measuring method.

FIG. 5 is likewise a cross-sectional explanatory view taken along the line VV in FIG.

FIG. 6 is likewise a flowchart illustrating a measuring method.

FIG. 7 is likewise a flowchart illustrating a measuring method.

FIG. 8 is an explanatory diagram illustrating a conventional method.

FIG. 9 is an explanatory diagram similarly illustrating a conventional method.

[Explanation of symbols]

1 ... Assembly line 2 ... Car body 3 ... Car body 4 ... Front fender 5 ... Rear quarter 6 ... Rear skirt 7 ... Front hood 8 ... Front door 9 ... Rear door 10 ... Trunk lid 11 ... Assembly accuracy measuring device 13 ... Robot 13a ... Arm tip 14 ... Measuring device 14a ... Laser emitter 14b ... CCD camera 14c ... Calculation unit 15 ... Reader 16 ... Control unit A ... Alignment point to be measured B ... Alignment point to be measured C ... Alignment point to be measured D ... Measurement position Alignment point to be measured E ... Alignment point to be measured F ... Alignment point to be measured DB ... Surface difference Pa ₁ ... Surface difference reference point Pa ₂ ... Surface difference reference point Pa ₃ ... Surface difference reference point Pb ₁ ... Surface difference reference point a ... Arc O ... Center RO ... Radius Rb ... Distance from center to surface difference reference point Pb ₁

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23Q 17/00-23/00 B62D 65/00 B23P 19/00-21/00 G01B 11/00-11 / 30 G01B 21/00-21/32

Claims (2)

(57) [Claims] 1. A CCD irradiates the alignment points of adjacent members to be measured with a one-dimensional laser beam in a transverse direction to obtain a CCD.
In an assembly accuracy measuring method for detecting a point on the both members irradiated by the camera as a reference point, and calculating a surface difference between the two members based on the detection signal, in the assembling accuracy measuring method, two members on the laser beam irradiation for one member are detected. Obtain the center of the approximate circle and the radius of the approximate circle having the point sequence formed by the reference point and the other reference points on the member existing between these reference points as an arc, and on the laser beam irradiation on the other member. A method for measuring assembly accuracy, characterized in that a distance between a reference point and a center of the approximate circle is obtained, and a difference between the distance and the radius is used as a surface difference between both members. 2. A CCD is irradiated with a one-dimensional laser beam in a transverse direction at alignment points of adjacent members to be measured, and a CCD
In an assembly accuracy measuring method for detecting a point on the both members irradiated by the camera as a reference point, and calculating a surface difference between the two members based on the detection signal, in the assembling accuracy measuring method, two members on the laser beam irradiation for one member are detected. The coordinates of the reference points and other reference points on the member existing between these reference points are obtained, and the center coordinates of the approximate circle and the radius of the approximate circle having the coordinate data string formed by these coordinates as an arc are obtained, And the coordinates of the reference point on the laser beam irradiation in the other member is obtained, and the surface difference between both members is calculated from the distance between this coordinate and the center coordinate of the approximate circle and the radius of the approximate circle. A characteristic method of measuring assembly accuracy.