JPH10213425A - Measuring plate and device for measuring wheel alignment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the constitution of a device, to decrease the cost of manufacturing and to facilitate the control and the adjustment. SOLUTION: In a measuring plate 4, an optically uniform distance measuring region MLA is provided in the extending direction to the sides of the front and rear directions of a vehicle under inspection with respect to a measuring mark region MRK. Therefore, the distance to the measuring plate 4 can be accurately obtained without the effect on the measurement using the measuring mark region MRK by irradiating distance measuring light on the distance measuring region MLA. Thus, the accuracy of the measurement of wheel alignment can be improved. Furthermore, since the distance measuring region can be provided as the large area, outer distance measuring light emitting devices 6-1 and 6-2 for irradiating the distance measuring light can be used under the fixed state. The constitution of the device can be simplified without decreasing the measuring accuracy. Furthermore, the irradiating positions of the distance measuring light beams of the distance measuring light emitting devices 6-1 and 6-2 can be largely separated, and the angle measuring accuracy of the measuring plate 4 based on the distance difference of both parts can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring plate and a wheel alignment measuring device, and more particularly to a measuring device used in a vehicle basic characteristic measuring device for three-dimensionally measuring a displacement and an angle of a tire wheel when a vehicle is driven. The present invention relates to a plate and a wheel alignment measurement device that performs wheel alignment measurement using the measurement plate.

[0002]

2. Description of the Related Art A vehicle basic characteristic measuring device is known as a test device for measuring basic characteristics of a vehicle such as a suspension characteristic and a steering characteristic of a vehicle in a test room.
In the vehicle basic characteristic measuring device, a test vehicle is fixed at a predetermined position, a force such as rotation, left, right, up, down, front and back is applied to a tire wheel, and a measurement obtained in consideration of a reaction force generated at that time. By processing the data, it is possible to measure various vehicle basic characteristics.

[0003] As a part of the vehicle basic characteristic measuring device, a wheel alignment measuring device for measuring a wheel alignment such as a spin angle, a camber angle and a toe angle based on a distance from a reference position to a tire wheel side surface. There is. Conventional wheel alignment measuring devices generally support a tire wheel and are fixed on a platform driven by an actuator, and are connected to the tire wheel to mechanically detect the movement of the tire wheel. . This type of mechanical wheel alignment measurement device has a problem that high-speed measurement cannot be performed due to a reduction in measurement accuracy due to friction of a movable portion and restrictions due to inertial mass of components and the like.

In order to solve this problem, a non-contact wheel alignment measuring apparatus using a non-contact distance sensor such as a laser beam sensor or an ultrasonic sensor has been proposed. More specifically, a conventional optical wheel alignment measurement device includes a plurality of optical sensors (for example,
A measurement unit equipped with a laser displacement meter is installed on a platform on the side of the tire wheel, and the measurement unit is moved in the front-rear direction of the vehicle so that a measurement plate 4P ( FIG.
4) is optically measured, and the camber angle and the toe angle are determined based on the obtained measurement data.

[0005]

In the above-mentioned conventional optical wheel alignment measuring apparatus, the laser displacement meter follows the movement of the measuring plate 4P, and the laser beam is always irradiated onto the measuring plate P. The laser displacement meter is driven using a two-dimensional stage based on the origin position of the measurement plate 4P.

Therefore, there has been a problem that the device configuration is complicated and the manufacturing cost is increased. Also,
The drive control of the two-dimensional stage for driving the laser displacement meter becomes complicated, and the two-dimensional stage for improving the measurement accuracy, and further, the adjustment of the laser displacement meter becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a measuring plate and a wheel alignment measuring device capable of simplifying the structure of the device, reducing the manufacturing cost, and facilitating control and adjustment.

[0008]

According to a first aspect of the present invention, there is provided a measuring plate which is mounted so that an origin position coincides with a center of a rotation axis of a wheel of a vehicle to be inspected. A measurement mark area provided around the origin position including the origin position of the measurement plate, and a measurement mark area on which various measurement marks are drawn, and extends in the front-rear direction of the inspected vehicle with respect to the measurement mark area. And an optically uniform distance measuring area to which the distance measuring light is radiated from the outside.

According to the first aspect of the present invention, the measurement plate is provided with an optically uniform distance measurement area in a direction extending in the front-rear direction of the inspected vehicle with respect to the measurement mark area. Therefore, by irradiating the distance measurement area with the distance measurement light, the distance to the measurement plate can be accurately obtained without affecting the measurement using the measurement mark area.

According to a second aspect of the present invention, in the first aspect of the invention, the distance measuring area is provided in both front and rear directions of the vehicle to be inspected. According to the second aspect of the invention, in addition to the operation of the first aspect,
Since the distance measurement area is provided in both the front and rear directions of the vehicle to be inspected, it is possible to irradiate two distance measurement lights at a large distance in the front and rear direction of the vehicle to be inspected. It is possible to improve the angle measurement accuracy of the measurement plate using the difference in distance to the application light irradiation position.

According to a third aspect of the present invention, in the first or second aspect of the invention, the measurement mark area includes a first fiducial mark having the origin position as a center coordinate;
Assuming a plurality of first imaginary lines parallel to each other and a second imaginary line that intersects with the first imaginary line and is parallel to each other, an intersection position between the first imaginary line and the second imaginary line is set as central coordinates. A plurality of second reference marks and a plurality of correction lines parallel to one of the first virtual line or the second virtual line and having a constant separation distance are drawn. .

According to the third aspect of the present invention, in addition to the operation of the first or second aspect of the present invention, the first reference mark, the plurality of second reference marks, and the correction mark area are provided in the measurement mark area. Since the line is drawn, various wheel alignment measurements can be performed quickly and accurately by imaging the mark area for measurement and performing image processing.

According to a fourth aspect of the present invention, there is provided a wheel alignment measuring apparatus for measuring a wheel alignment using the measuring plate according to any one of the first to third aspects, wherein the predetermined reference distance is a predetermined distance from each other. Based on the distance measurement signal, at least two distance measurement means, each of which is fixed in advance at each position, emits the distance measurement light, and outputs a distance measurement signal corresponding to the distance to the measurement plate, Distance calculating means for calculating a distance to a predetermined position of the measurement plate corresponding to the reference position.

According to the fourth aspect of the invention, each of the distance measuring means is fixed in advance to a predetermined reference position which is separated from each other by a predetermined distance, emits light for distance measurement, and corresponds to the distance to the measurement plate. Outputs ranging signal. The distance calculation means,
Based on the distance measurement signal, a distance to a predetermined position on the measurement plate corresponding to the reference position is calculated.

[0015]

Preferred embodiments of the present invention will now be described with reference to the drawings. Schematic Configuration of Alignment Measuring Device FIG. 1 shows a schematic configuration block diagram of a wheel alignment measuring device.

The wheel alignment measuring device 1 is roughly classified into a measuring plate 4 attached to a tire wheel 3 of a measuring vehicle 2 and two CCs capable of color imaging.
Measurement plate 4 by imaging unit 5 having D camera
Of the test surface 4S, and a measurement unit 7 for measuring the distance of the measurement plate to the test surface 4S by the two laser displacement gauges 6-1 to 6-2, based on the output signal of the measurement unit 7. Data processing control unit 8 that performs alignment calculation and controls measurement unit 7
And is provided. Configuration of Measurement Plate FIG. 2 shows the measurement plate. FIG. 2A is a front view of the measurement plate, and FIG. 2B is a side view of the measurement plate.

The test surface 4S of the measurement plate 4 has a planar shape, and as shown in FIG. 2, a measurement mark area MRK on which various measurement marks are drawn and a measurement mark area M
It extends optically to the origin position O of the RK in the front-rear direction of the measuring vehicle 2 and is irradiated with measuring light of the laser displacement gauges 6-1 to 6-2 to optically measure the distance to the test surface 4S. And a uniform (that is, uniform in reflectivity) distance measurement area MLA.

The measurement mark area MRK includes a base portion BB colored black and a first circular mark MC as a reference mark centered on the origin O of the test surface 4S colored red.
1 and a plurality of first virtual lines parallel to each other (in FIG. 2A,
Only two first virtual lines VL11 and VL12 are shown. )
And a second virtual line that intersects the first virtual lines VL11 and VL12 and is parallel to each other (only two second virtual lines VL21 and V22 are shown in FIG. 2A). A plurality of blue-colored second circle marks MC2 centered at the intersections of the virtual lines VL11, VL12 and the second virtual lines VL21, V22, and the first virtual lines VL11, VL12 or the second virtual line VL21, V22 (in FIG. 2A, parallel to the second imaginary lines VL21, V22) and a plurality of corrections drawn in white with a constant distance Δd. And a service line CL.

Since the above-mentioned circle marks MC1 and MC2 and the correction line CL are used as a measurement scale, they need to be drawn with a predetermined accuracy so as to achieve a desired accuracy.
As shown in the perspective front view of FIG. 2B and FIG. 3, on the back surface of the measurement plate, a mounting bracket HLD for mounting to the tire wheel 3 of the measurement vehicle 2 and a camber angle of the tire wheel 3 are measured. And a second inclination data DSL for measuring the caster angle of the tire wheel 3.
And a caster angle measuring inclinometer SCAS that outputs 2.

FIG. 4 is a detailed explanatory view of the measurement mark area MRK of the measurement plate 4. In the measurement mark area MRK, the center of the first circle mark MC1 and the first circle mark MC1
1, the distance between the center of the second circle mark MC2 and the center of the second circle mark MC2 and the center of the second circle mark MC2.
Are spaced apart by the distance Lx from the center of the second circle mark MC2 closest to.

The distance between the center of the first circle mark MC1 and the center of the second circle mark MC2 closest to the first circle mark MC1 in the Z direction, the center of the second circle mark MC2 and the two circle mark M
The distance in the Z direction from the center of the second circle mark MC2 closest to C2 is spaced by the distance Lz.

In this case, the distance Lx and the distance Lz do not necessarily have to be equal, but it is preferable to set Lx = Lz in order to simplify the arithmetic processing.

A certain correction line CL and a certain correction line C
The correction line CL closest to L is arranged at a distance Δd. In this case, in order to simplify the image processing, the correction line CL is set to the first circle mark MC1.
It is preferable to set Δd = Lz so as not to overlap with the second circle mark MC2, and to set the distance between the correction line CL and the center of the second circle mark MC2 to Δd / 2 = Lz / 2. .

Further, the diameter RMC of the first circle mark MC1
1 and the diameter RMC2 of the second circle mark MC2, since the first circle mark MC1 is used for coarse (rough) measurement and the second circle mark MC2 is used for precise (fine) measurement, RMC1 ≒ 2 × RMC2 is preferred from the viewpoints of measurement accuracy, ease of image processing, etc., and the size of the second circle mark MC2 is 1
[Cm] is preferable.

The dimensional tolerance is preferably within ± several tens [μm] when the final target accuracy is about several hundreds [μm]. In the above description, the first circle mark MC1 is colored red and the second circle mark MC2 is colored blue, but any one of the three primary colors of light, red, green and blue, which are different from each other, is used. The processing described below is also possible.

In this case, it is preferable to set the color of the first circle mark MC1 to a color other than the color included in the imaging screen of the measurement vehicle 2 in order to prevent a data processing error from occurring. More specifically, for example, when the measurement vehicle 2 is painted red, the first circle mark is green.

Similarly, the base portion BB is black and the correction line C
Although L is white, image processing described later can be performed in the opposite case. In the present embodiment, the first virtual line VL1
1, VL12 and the second imaginary lines VL21, VL22 are orthogonal to each other. However, the present invention is not limited to this. The arithmetic processing becomes complicated, but at predetermined intervals so as to intersect at a predetermined angle. The same effect can be obtained if it is assumed that they are arranged.

Configuration of Measurement Unit FIG. 5 is a partial perspective external view of the measurement unit, FIG. 6 is a front view of the measurement unit, and FIG. 7 is a side view of the measurement unit. The measuring unit 7 includes two laser displacement meters 6-1 to 6
A holding plate 10 having a substantially "U" -shape for holding -2;
The imaging unit 5 is provided on the back side of the holding plate 10 so as to image the measurement plate 4 from behind the holding plate 10 through the opening 5A (see FIG. 7).

In this case, the measurement plate position 4UP when the measurement plate 4 is positioned most upward in the measurement allowable range and the measurement plate position when the measurement plate 4 is positioned most downward in the measurement allowable range. Position 4DN, where the measurement plate position is 4F symmetrical with respect to the measurement plate position 4FR with respect to the measurement plate position 4FR and the origin O when located closest to the front of the measurement vehicle 2 In any of the measurement plate positions (not shown), the laser displacement meter 6 is
The laser emission surfaces LP of -1 to 6-2 are held at positions where measurement light can be applied to the distance measurement area MLA of the measurement plate 4. Shows a schematic configuration block diagram of a data processing control unit 8 in block diagram 8 of a processor body.

The data processing control unit 8 is provided with a first imaging data DGG output from a color CCD camera 5A to be described later.
1 or a display 25 for displaying an image based on the second imaging data DGG2 output from the color CCD camera 5B, and a first image output from the imaging unit 5
Color separation processing for performing color separation processing based on the imaging data DGG1 and the second imaging data DGG2 and outputting red imaging data DR corresponding to red, green imaging data DG corresponding to green, and blue imaging data DB corresponding to blue. Circuit 2
7 and output signals DLD of two laser displacement gauges 6-1 to 6-2
1 to DLD2, the first tilt data DSL1 output from the camber angle measuring inclinometer SCAM, the second tilt data DSL2 output from the caster angle measuring inclinometer SCAS, and the red image data D
Based on R, green imaging data DG, and blue imaging data DB, a test of the measurement plate 4 at a predetermined position (for example, the center position of the imaging screen) in the high-resolution imaging screen of the two imaging screens of the imaging unit 5. X coordinate data X on the surface 4S, Y coordinate data Y on the test surface 4S, Z coordinate data Z on the test surface 4S of the measurement plate 4 at a predetermined position in the high-resolution imaging screen, and inclination of the test surface 4S with respect to the X axis. an arithmetic processing unit 28 that outputs θx, the inclination θy of the test surface 4S with respect to the Y axis, and the inclination θz of the test surface 4S with respect to the Z axis (these inclinations serve as a reference for the calculation of the spin angle data DSP). It is configured.

In this case, the red image data DR includes the first red image data DR1 corresponding to the first image data DGG1 and the second image data DGG2 corresponding to the second image data DGG2.
Red imaging data DR2 is included, and green imaging data DG includes first green imaging data DG1 corresponding to first imaging data DGG1 and second imaging data DGG2 corresponding to second imaging data DGG2.
The green image data DG2 is included, and the blue image data DB includes first blue image data DB1 corresponding to the first image data DGG1 and second image data DGG2 corresponding to the second image data DGG2.
It is assumed that blue image data DB2 is included. Configuration of Imaging Unit FIG. 9 shows a schematic configuration diagram of the imaging unit.

The image pickup unit 5 has an optical axis forming a predetermined angle θCCD with an optical axis of a color CCD camera 5B described later, and has a visual field ARA (see FIG. 10) on the test surface 4S of the measurement plate 4. 1 has a low-resolution color CCD camera 5A for outputting the imaging data DGG1, and an optical axis perpendicular to the test surface 4S of the measurement plate 4 in an initial state;
A high-resolution color CCD camera 5B having a visual field ARB (see FIG. 10) on the test surface 4S of the measurement plate 4 and outputting the second image data DGG2 is provided.

In this case, the predetermined angle θCCD is between the maximum displacement position 4SFR in the positive Y-axis direction and the maximum displacement position 4SRR in the negative Y-axis direction of the test surface 4S corresponding to the initial reference position 4SREF in the Y-axis direction of the test surface 4S. , Optical axis position of color CCD camera 5A on test surface 4S and color CCD camera 5
The difference ΔE in the Z-axis direction from the optical axis position of B is set so as to fall within a preset maximum allowable error range.

The field of view AR of the color CCD camera 5B
B is included in the field of view ARA of the color CCD camera 5A as shown in the perspective view of FIG. 10A and the front view of FIG.
Is set to cover almost the entire area of the test surface 4S of the measurement plate 4.

Therefore, for example, the color CCD camera 5
When the same pixel number is used as A and 5B, the color CCD camera 5A captures a wide area, so that the resolution is substantially low, and the position can be detected only with low accuracy. Since the region is imaged, the resolution is substantially high, and the position can be detected with high accuracy.

In this case, since the actual distance to the measurement plate differs between the two color CCD cameras, it is necessary to correct the distance when performing more precise measurement.
In the present embodiment, the two color CCD cameras 5A and 5B are of a multi-optical axis system in which the optical axes are not aligned. However, as shown in FIG.
It is also possible to use a single optical axis system in which the optical axes of A 'and 5B' are matched.

More specifically, the color CCD camera 5A '
And a color CCD camera 5A 'and a color CCD camera 5
And a half mirror 5C arranged in the optical path of B ′. Also in this case, the field of view ARB of the color CCD camera 5B 'is the same as the perspective view of FIG.
As shown in the front view of FIG.
The field of view ARA of A ′ is included in the field of view ARA, and the field of view ARA of the color CCD camera 5A ′ is set so as to cover almost the entire area of the test surface 4S of the measurement plate 4.

As a result, even when precision measurement is performed,
There is no need to perform distance correction. Two color CCDs in either multi-optical axis system or single optical axis system
It suffices if the absolute positional relationship between the cameras 5A 'and 5B' is known and the positional relationship is maintained without change during the measurement. FIG. 13 shows an arrangement diagram of the laser displacement meter. FIG. 13 (a)
Fig. 13B is a perspective view of the arrangement of the laser displacement meter, Fig. 13B is a side view of the arrangement of the laser displacement meter in an initial state, and Fig. 13C.
FIG. 4 is an arrangement side view in a measurement state of the laser displacement meter.

The laser displacement meters 6-1 to 6-2 are shown in FIG.
13 (b), in the initial state, the measurement light irradiation point P1 of the laser displacement meter 6-1 and the laser displacement meter 6-
An imaginary line connecting the measurement light irradiation points P2 is the first circle mark MC1.
Are arranged so as to include the origin O which is the center point of.

The measurement light emission point of the laser displacement meter 6-1 and the measurement light emission point of the laser displacement meter 6-2 are a distance LX ″.
Are only spaced apart. Measurement Operation Next, the measurement operation will be described with reference to FIGS.

In this case, the first screen is always displayed on the imaging screen of the color CCD camera 5A constituting the imaging unit 5.
It is assumed that a circle mark MC1 is set to be included, and a test surface 4S
It is assumed that the measurement plate 4 is mounted so that the origin O of the tire wheel 3 coincides with the rotation center axis of the tire wheel 3.

FIG. 14 shows a flowchart of the measuring operation process. First, the operator drives the tire wheels 3 of the measurement vehicle 2 upward or downward independently for each tire wheel by an actuator (not shown). Then, the actuator is stopped at the empty vehicle load value, and the state at the time of stop is maintained (step S1).

Next, the holding plate 10 and the imaging unit 5 are driven in the Z-axis direction by manual operation, and
0 and the imaging unit 5 are opposed to the test surface 4S of the measurement plate 4, and the optical axes of the color CCD camera 5A and the color CCD camera 5B constituting the imaging unit 5 are aligned with the test surface 4S.
(Step S2).

As a result, a virtual line connecting the irradiation points P1 and P2 of the measuring laser light of the laser displacement meters 6-1 and 6-2 is set so as to include the origin O. As a result, the arithmetic processing circuit 28 can calculate the distance to the first circle mark MC1 on the test surface 4S of the measurement plate 4 based on the output signals DLD1 to DLD2 of the laser displacement meters 6-1 to 6-2.

More specifically, the distance measuring area M of the measuring plate 4 corresponding to the output signal DLD1 of the laser displacement meter 6-1.
The distance to LA is LY1, and the distance measurement area M of the measurement plate 4 corresponding to the output signal DLD2 of the laser displacement meter 6-1.
Assuming that the distance to LA is LY2, the first EN mark MC1
The distance LMC1 to LMC1 is as follows: LMC1 = (LY1 + LY2) / 2.

In this state, the relationship between the measurement plate 4, the field of view ARA of the color CCD camera 5A and the field of view ARB of the color CCD camera 5B is shown in FIG. 10 (a) or FIG.
In the state of (a), the imaging unit 5 images the test surface 4S of the measurement plate 4 (step S3),
The first imaging data DGG1 and the second imaging data DGG2 are output to the color separation processing circuit 27 of the processor 8A (step S4).

Under the control of the controller 25, the color separation processing circuit 27 separately performs the color separation processing of the first image data DGG1 and the second image data DGG2 output from the image pickup unit 5 to correspond to red. Processing unit 28 converts red imaging data DR, green imaging data DG corresponding to green, and blue imaging data DB corresponding to blue.
(Step S5).

Here, a specific calculation process will be described with reference to FIGS. As shown in FIG. 15, the focal length of the lens of the color CCD camera 5A is f = f5A [m
m], and the number of pixels of the color CCD camera 5A is, for example,
Nx × Nz [dots] (Nx and Nz are natural numbers; for example, Nx = 400, Nz = 400), and the focus is on the test surface 4S so that the field of view ARA can cover the area of L5A × L5A [mm]. If the color CCD camera 5A is arranged at a distance Lf5A corresponding to the distance f5A, and Nx = Nz = NN (NN: natural number), one pixel corresponds to the pitch of L5A / NN [mm]. .

Next, in order to obtain the center coordinates of the Z axis, FIG.
As shown in the figure, based on the first red imaging data DR1,
Color CCD camera 5A while scanning in the positive X-axis direction
In the first predetermined direction (for example, the positive direction of the Z-axis; upward in FIG. 16) from the center coordinate CCA, for example, at a DN dot interval (equivalent to DN · L5A / NN [mm] interval in the above example). A rough search is performed to detect the first circle mark MC1 (step S6). In this case, the setting of DN must satisfy the condition of DN · L5A / NN ≦ RMC1 in relation to the diameter RMC1 of the first circle mark MC1.

If the first circle mark MC1 is detected by the rough search in step S6, as shown in FIG. 17A, one dot interval (L5A / NN [m
m] interval, fine scanning is performed while scanning in the positive direction of the X-axis, and the detection is continued until the first circular mark MC1 cannot be detected. The pixel number in the Z-axis direction at the time of detecting the circle mark MC1 (N1th dot (N1 = 1 to NN) of NN dots) is stored.

Then, as shown in FIG.
The direction opposite to the predetermined direction (for example, the negative direction of the Z axis;
A fine search is performed (downward) (step S7). In the process of step S7, if the first circle make MC1 cannot be detected again, the pixel number in the Z-axis direction at the time when the first circle mark MC1 is finally detected (N2 of NN dots, N2
Based on the dot (N2 = 1 to NN), Z
The axis center coordinates Z0 are obtained (step S8).

Z0 = (N1 + N2) / 2 Here, the Z-axis center coordinate Z0 is substantially equal to the Z-coordinate of the center coordinate of the first circle mark MC1, and the accuracy of the obtained Z-axis center position Z0 is ± L5A / NN [mm]. Subsequently, similarly, in order to obtain the center coordinate X0 of the X axis, while scanning in the positive direction of the Z axis based on the first red imaging data DR1,
From the center coordinate CCA of the color CCD camera 5A, a rough search is performed in a third predetermined direction (eg, the positive direction of the X-axis; rightward in FIG. 15) at, for example, DN dot intervals (equivalent to DN · L5A / NN [mm] intervals). Then, the first circle mark MC1 is detected (step S9).

If the first circle mark MC1 is detected by the rough search in step S9, one dot interval (L5A / N
Fine search is performed in units of (N [mm] intervals), and the detection is continued until the first circle mark MC1 cannot be detected. When the first circle mark MC1 cannot be detected, the first circle mark MC1 is finally detected. The pixel number in the X-axis direction at the time (M1 dot (M1 = 1 to N
N)), and the direction opposite to the third predetermined direction (for example, X
Fine search is performed in the negative axis direction (left direction in FIG. 16) (step S10).

In the process of step S10, the first
If the circle mark MC1 can no longer be detected, the pixel number in the X-axis direction (N
Based on the M2 dot (M2 = 1 to NN) of the N dots, the X-axis center coordinate X0 is obtained by the following equation (step S11).

X0 = (M1 + M2) / 2 As a result, the accuracy of the obtained X-axis center coordinate X0 is ± L5A
/ NN [mm]. On the other hand, as shown in FIG. 18, the focal length of the lens of the color CCD camera 5B is set to f = f5B
[Mm], and the number of pixels of the color CCD camera 5B is set to the first
The color CCD camera is set to Nx × Nz [dots] similarly to the color CCD camera, and separated from the test surface 4S by the distance Lf5B corresponding to the focal length f5B so that the field of view ARB can cover the area of L5B × L5B [mm]. Assuming that 5B is arranged and Nx = Nz = NN (NN: natural number), one pixel corresponds to the pitch of L5B / NN [mm].

Next, as shown in FIG.
The second red imaging data DR2 output from the camera 5B,
The correction line CL is sampled based on a white image obtained by adding the green imaging data DG2 and the second blue imaging data DB2, and a least squares method (LSM: Least Squares Method) is obtained from a plurality of position data. Of the correction line CL is determined by the above (Step S12).

Subsequently, based on the image picked up by the color CCD camera 5A, the center coordinates (X0, Z0) of the first circle mark MC1 obtained in the processing of steps S8 and S11 and the color CC
The distance LL between the D camera 5B and the center coordinate CCB of the visual field ARB is obtained (step S13).

Thus, the correction line CL surrounding the center coordinates of the visual field ARB can be specified, and the approximate position of the visual field ARB can be grasped. Furthermore, this first circle mark M
In parallel with the calculation of the center coordinates (X0, Z0) of C1 and the distance LL, the arithmetic processing circuit 28 controls the laser displacement meters 6-1 to 6-2.
Based on the output signals DLD1 to DLD2, the distance between the irradiation point P1 and the irradiation point P2 on the test surface 4S of the measurement plate 4, that is, the optical axis position of the camera 5B is calculated (step S14).

Here, the calculation of the distance to the optical axis position will be specifically described. In this case, as shown in FIG. 20, the laser emitting section P6-1 of the laser displacement gauges 6-1 to 6-2.
To P6-2 (the symbols P6-1 to P6-2 are also used to indicate the position of the emission unit) are on a virtual plane VPL including a straight line VL parallel to the vertical direction of the measurement vehicle. The emission unit P6 is disposed at a position equidistant from the straight line VL on the straight line VL and on a straight line orthogonal to the straight line VL.
-1 and P6-2 are respectively arranged.

As shown in FIG. 20, the distance to the irradiation point P1 on the distance measuring area MLA of the measuring plate 4 corresponding to the output signal DLD1 of the laser displacement meter 6-1 is LP1, and the laser displacement meter 6-2 The distance to the irradiation point P2 on the distance measuring area MLA of the measuring plate 4 corresponding to the output signal DLD2 of
Then, the midpoint P of the line segment connecting the irradiation points P1 and P2
The distance to P, that is, the distance LPP to the optical axis position of the camera 5B is LPP = (LP1 + LP2) / 2.

As a result, the magnification of the imaging screen according to the distance between the camera 5B and the test surface 4S of the measurement plate 4 can be grasped, and the actual dimensions can be easily obtained and corrected in the image processing. Becomes Measurement of Toe Angle In parallel with the calculation of the distance to the optical axis position, the arithmetic processing circuit 28 measures the toe angle (step S15).

More specifically, the toe angle θTOE is calculated as shown in FIG.
Has the following relationship: tan (θTOE) = LPY / LX ″ Here, the distance LX ″ is the separation distance between the measurement light emission point of the laser displacement meter 6-1 and the measurement light emission point of the laser displacement meter 6-2 (FIG. 13). Therefore, the toe angle θTOE to be obtained is θcam = tan ⁻¹ (LPY / LX ″). Here, since LPY = | LP1−LP2 |, θTOE = tan ⁻¹ (| LP1−LP2 | / LX ").

At this time, according to the measuring plate of the present embodiment, the distance X ″ between the irradiation point P1 and the irradiation point P2 can be increased, so that the measurement accuracy of the toe angle θTOE can be improved. Next, the calculation of the center coordinates of the visual field ARB will be described with reference to FIGS.

First, the center coordinates CCA of the field of view ARA and the first circle mark MC1 are displayed on the image screen of the color CCD camera 5A.
Then, the distance da from the center coordinates (X0, Z0) is calculated (step S16). da = √ (xa ² + ya ² ) Next, a line parallel to the correction line CL passing through the center coordinates of the field of view ARA is assumed, and this line is connected to the center coordinates of the field of view ARA and the center coordinates of the first circle mark MC1. The angle θa formed by the line is calculated (step S17).

Θa = tan ⁻¹ (ya / xa) −θ0 From these, the distance da obtained in steps S14 and S15 is obtained.
Then, the distance Xa and the distance Ya are calculated based on the angle θa (step S18). Xa = da × cos (θa) Ya = da × sin (θa) Next, based on the distance Xa and the distance Ya, the second circle mark MC2n located closest to the center coordinates of the visual field ARA is determined by the first circle mark.
It is determined whether the mark is the nx-th (nx is a natural number) second circle mark in the X direction and the ny-th (ny is a natural number) second circle mark in the Z direction when viewed from the circle mark MC1 (step S).
19). In FIG. 21, nx = 4 and ny = 3 for the second circle mark MC2n.

Nx = int (Xa / Lx) ny = int (Ya / Lz) where int (R) represents the largest integer not exceeding R, and Lx is the second circle in the X-axis direction. The distance between the marks MC2 (see FIG. 3) and Lz is the distance between the second circular marks MC2 in the Z-axis direction (see FIG. 3).

Thus, the center coordinates (X0, Z) of the second circle mark MC2n located closest to the center coordinates of the visual field ARA.
0) from the center coordinate of the first circle mark MC1 to Xb,
Yb is calculated (step S20). This distance Xb, Yb
Has a high precision value corresponding to the drawing precision of the first circle mark MC1 and the second circle mark MC2.

Xb = nx × Lx Yb = ny × Lz Subsequently, the distance dd (low accuracy) from the center coordinate of the second circle mark MC2n closest to the center coordinate of the visual field ARA to the center coordinate of the visual field ARA, and An angle θi (low accuracy) formed between the visual field ARA and the X axis is calculated (step S21). Here, the low accuracy means the measurable accuracy based on the image data of the color CCD camera 5A (± 1 [mm] in the above example).
Precision).

Dd = {(Xa−Xb) ² + (Ya−Yb) ² } θi = tan ⁻¹ {(Ya−Yb) / (Xa−Xb)} + θ0 Next, the distance dd and the angle θi are obtained. Based on the field of view ARA
And the low-precision distances Xi and Yi between the center coordinates of the second circle mark MC2n located closest to the center coordinates of the visual field ARA are calculated (step S22).

Xi = dd × cos (θi) Yi = dd × sin (θi) Further, based on the low-precision distances Xi and Yi, the color CC
The center coordinates of the second circle mark MC2n with respect to the center coordinates of the visual field ARb of the D camera 5B are converted into dot addresses IX and IY (address display based on the number of dots) (step S2).
3).

In this case, since the visual field ARB is composed of NN × NN (dots) as described above, the dot address of the center coordinate of the visual field ARB in the X direction = NN / 2,
The dot address of the center coordinate in the Y direction = NN / 2. IX = NN / 2 + Xi × Sn / Lx IY = NN / 2−Yi × Sn / Lz Here, Sn is the number of dots per 1 [mm].

Next, based on the distances Xb and Yb, the color CC
On the visual field ARB of the D camera 5B, the distance Db (high precision) between the central coordinates of the visual field ARB and the central coordinates of the second circle mark MC2n.
And the angle θb (high accuracy) between the visual field ARA and the X axis is calculated (step S24). Here, the high precision means a measurable precision based on the image data of the color CCD camera 5B (± L5B / NN [mm] precision in the above example).

Db = √ (Xb ² + Yb ² ) θb = tan ⁻¹ (nYb / Xb) + θ0 Based on the calculated distance Db and angle θb, the visual field AR
The high-precision distances Xc and Yc between the center coordinates of B and the center coordinates of the second circle mark MC2n closest to the center coordinates of the visual field ARB are calculated (step S25).

Xc = Db × cos (θb) Yc = Db × sin (θb) Subsequently, the high-precision distances Xc and Yc and the dot address IX,
Field of view ARb of color CCD camera 5B based on IY
The center coordinates of the second circle mark MC2n with respect to the center coordinates are converted into dot addresses X and Y (address display based on the number of dots) (step S26).

In this case, since the field of view ARB is composed of NN × NN (dots) as described above, the dot address of the center coordinate of the field of view ARB in the X direction = NN / 2,
The dot address of the center coordinate in the Y direction = NN / 2. X = Xc + (NN / 2 + IX) × Lx / Sn Y = Yc + (NN / 2−IY) × Lz / Sn Further, the obtained dot addresses X and Y are based on the X axis and Z axis of the test surface 4S of the measurement plate 4. Is converted to a coordinate system of the following formula, and dot addresses x and y in the coordinate system based on the X axis and the Z axis of the test surface 4S are calculated (step S2).
7). In this case, the following equation is established: X = x / cos (θx) Y = y / cos (θy) From these equations, the dot addresses x and y are obtained as follows: x = X × cos (θx) y = Y × cos (θy).

Next, the arithmetic processing section 28 calculates the caster angle θcas based on the second tilt data DSL2 output from the caster angle measuring inclinometer SCAS (step S28), and outputs the camber angle measuring inclinometer SCAM. First inclination data DSL1
Camber angle θcam is calculated based on
9).

According to the present embodiment as described above,
With the laser displacement meter fixed, the distance in the Y direction to the measurement plate can be accurately calculated, and there is no need to provide an XY stage or the like for driving the laser displacement meter. It is possible to reduce the device manufacturing cost.

In the above embodiment, the distance measurement areas MLA are provided in both the front and rear directions of the measurement vehicle 2 with respect to the measurement mark area MRK. However, the measurement accuracy is reduced because the measurement cannot be performed, but it is also possible to provide the measurement device in any one direction.

[0079]

According to the first aspect of the present invention, the measurement plate has an optically uniform distance measurement area in a direction extending in the front-rear direction of the test vehicle with respect to the measurement mark area. Is provided, by irradiating the distance measurement area with the distance measurement light, it is possible to accurately determine the distance to the measurement plate without affecting the measurement using the measurement mark area, The accuracy of the wheel alignment measurement can be improved.

Further, since the distance measuring area can be made large, it is possible to use the external distance measuring light irradiating device for irradiating the distance measuring light in a fixed state, thereby lowering the measuring accuracy. Therefore, the configuration of the wheel alignment measuring device can be simplified.

According to the second aspect of the invention, in addition to the operation of the first aspect, the distance measurement areas are provided in both front and rear directions of the vehicle to be inspected. It is possible to irradiate the light at a large distance in the front-rear direction of the vehicle to be inspected, and it is possible to measure the angle of the measuring plate with high accuracy using the difference in distance between the two irradiation positions of the rejection light. The accuracy of the wheel alignment measurement can be further improved.

According to the third aspect of the present invention, in addition to the operation of the first or second aspect of the present invention, the first reference mark, the plurality of second reference marks, and the correction mark area are provided in the measurement mark area. Since the line is drawn, various wheel alignment measurements can be performed quickly and accurately by imaging the mark area for measurement and performing image processing.

According to the fourth aspect of the present invention, each of the distance measuring means is fixed in advance to a predetermined reference position which is separated from each other by a predetermined distance, emits distance measuring light, and corresponds to the distance to the measuring plate. A distance measurement signal is output to the distance calculation means, and the distance calculation means calculates a distance to a predetermined position of the measurement plate corresponding to the reference position based on the distance measurement signal, so that a driving mechanism for driving the distance calculation means is provided. In spite of the simplicity of the device configuration without the necessity of providing, the distance measurement accuracy, and thus the angle measurement accuracy of the measurement plate, can be maintained with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration block diagram of a wheel alignment measurement device.

FIG. 2 is an explanatory diagram of a measurement plate.

FIG. 3 is a transparent front view of a measurement plate.

FIG. 4 is a diagram illustrating a detailed configuration of a measurement plate.

FIG. 5 is a perspective view illustrating the arrangement of a measurement unit.

FIG. 6 is a side view of the measurement unit.

FIG. 7 is a front view of the measurement unit.

FIG. 8 is a schematic configuration block diagram of a data processing control unit.

FIG. 9 is a schematic configuration block diagram of an imaging unit.

10 is an explanatory diagram of a field of view of a color CCD camera in the imaging unit in FIG. 9;

FIG. 11 is a schematic block diagram of another imaging unit.

FIG. 12 is a color CCD in the imaging unit of FIG. 10;
It is explanatory drawing of the visual field of a camera.

FIG. 13 is an explanatory view of an arrangement of a laser displacement meter.

FIG. 14 is a flowchart of a measurement operation process.

FIG. 15 is an explanatory diagram of an imaging area of a color CCD camera 5A.

FIG. 16 is an explanatory view (1) of scanning a first circle mark.

FIG. 17 is an explanatory view (2) of scanning a first circle mark.

FIG. 18 is an explanatory diagram of an imaging area of a color CCD camera 5B.

FIG. 19 is an explanatory diagram (part 1) of the wheel alignment measurement.

FIG. 20 is an explanatory diagram of distance measurement.

FIG. 21 is an explanatory diagram of toe angle θTOE measurement.

FIG. 22 is an explanatory diagram (part 2) of the wheel alignment measurement.

FIG. 23 is an explanatory view (part 3) of the wheel alignment measurement.

FIG. 24 is a schematic explanatory diagram of wheel alignment measurement.

[Explanation of symbols]

 Reference Signs List 1 wheel alignment measuring device 2 measuring vehicle 3 tire wheel 4 measuring plate 4S test surface 5 imaging unit 5A opening 5A, 5B color CCD camera 5C half mirror 6-1 to 6-2 laser displacement meter 7 measuring unit 8 data processing control unit 9 Forced head 10 Holding plate 25 Display 27 Color separation processing circuit 28 Arithmetic processing unit ARA, ARB visual field BB Base unit CL Correction line DR Red imaging data DR1 First red imaging data DR2 Second red imaging data DG Green imaging data DG1 First 1 green imaging data DG2 2nd green imaging data DGG1 1st imaging data DGG2 2nd imaging data DB blue imaging data DB1 1st blue imaging data DB2 2nd blue imaging data DLD1 to DLD2 output signal DSL1 first inclination data DSL2 second inclination Data MC1 Backslash MC2 second circular mark O origin P1~P2 irradiation point SCAM camber angle measuring inclinometer SCAS caster angle measuring inclinometer VL11, VL12 first virtual line VL21, VL22 second imaginary line

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[Procedure amendment]

[Submission date] February 3, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Patent application title: Measuring plate and wheel alignment measuring device

Claims (4)

[Claims] 1. A measurement plate mounted so that an origin position coincides with a center of a rotation axis of a wheel of a vehicle to be inspected, provided around the origin position including the origin position of the measurement plate, and used for various kinds of measurement. A mark area for measurement on which a mark is drawn, and an optically uniform, which is provided in a direction extending in the front-rear direction of the vehicle to be inspected with respect to the mark area, and is irradiated with light for distance measurement from outside. A measuring plate comprising: a distance measuring area; 2. The measurement plate according to claim 1, wherein the distance measurement area is provided in both front and rear directions of the vehicle to be inspected. 3. The measurement plate according to claim 1, wherein the measurement mark area includes a first reference mark whose center coordinate is the origin position, and a plurality of first virtual lines parallel to each other. A plurality of second fiducial marks intersecting with the first virtual line and assuming parallel second virtual lines, and having, as central coordinates, an intersection position between the first virtual line and the second virtual line; A measurement plate, wherein a plurality of correction lines are drawn parallel to one of the first imaginary line and the second imaginary line and the distance between them is constant. 4. A wheel alignment measuring device for measuring wheel alignment using the measuring plate according to claim 1, wherein the wheel alignment measuring device is fixed in advance at predetermined reference positions separated by a predetermined distance from each other. At least two distance measuring means for emitting the distance measuring light and outputting a distance measuring signal corresponding to the distance to the measuring plate; and corresponding to the reference position based on the distance measuring signal. And a distance calculating means for calculating a distance to a predetermined position of the measurement plate.