JPH0261790B2 - - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a positional deviation detection system, and more particularly to a system for detecting positional deviation in a plane including the insertion direction of an object to be inserted into a housing.

(Description of Prior Art) Conventionally, as a housing insertion system, there is a system in which, for example, a terminal connected to an electric wire is inserted into a housing. FIG. 1 is a schematic diagram showing an example of a terminal and a housing that are inserted using such a system. The housing 1 has an appropriate number (six in the figure) of insertion holes,
The terminal 3 connected to the electric wire 2 is inserted into one of the insertion holes, for example, along the illustrated dashed line.

The inside of the insertion hole has a structure as shown in FIG. 2, for example. At the top and bottom of the insertion hole,
An upper guide part 4 and a lower guide part 5 are provided for guiding the terminal 3. The upper guide part 4 is
Slanted surface 6 that becomes higher toward the inside from the entrance of the insertion hole
has. By the action of the inclined surface 6, the terminal 3 properly fitted into the entrance of the insertion hole is positioned between the flat part of the upper guide part 4 and the lower guide part 5 as it is inserted. The upper guide part 4 further includes:
A stopper portion 7 and a detent claw 8 are provided. The terminal 3 whose tip end has been inserted up to the stopper portion 7 is prevented from returning in the opposite direction to the insertion direction by the action of the claw 8.

FIG. 3 is a schematic cross-sectional view schematically showing the above-mentioned insertion operation. As shown in Figure 3a,
The terminal 3 properly fitted into the entrance of the insertion hole is pushed forward in the insertion direction indicated by the solid arrow and comes into contact with the inclined surface 6 of the upper guide portion 4. FIG. 3b shows the state in which the terminal 3 has been pushed further. terminal 3
As it is inserted, it is slid downward by the action of the inclined surface 6 and is positioned between the flat part of the upper guide part 4 and the lower guide part 5. In this state, the claw 8 made of an elastic material is pushed upward by the terminal 3. FIG. 3c shows a state in which the terminal 3 has been inserted. In this state, the tip of the terminal 3 reaches the stopper portion 7, and the claw 8 is restored to its original state due to its elasticity, thereby preventing the terminal 3 from returning.

When inserting a terminal into the housing as described above, a particular problem with conventional housing insertion systems is how to properly guide and position the terminal to the entrance of the insertion hole of the housing. If this positioning is insufficient, insertion errors will naturally occur. In order to avoid insertion errors and improve the performance of the housing insertion system, it is necessary to position the terminals very carefully. As a cause of positional displacement of the terminal, for example, rotation or movement of the terminal tip caused by twisting or constriction of the electric wire when the electric wire connected to the terminal is gripped by the transfer means can be cited. FIG. 4A shows an example in which the terminal rotates, and FIG. 4B shows an example in which the terminal moves upward. Both of these positional deviations A and B are within the permissible range, and if the terminal is pushed in the insertion direction as it is, the terminal can be positioned at a predetermined position within the housing by the action of the above-mentioned inclined surface 6.
However, for example, if the terminal rotates more than A or moves upward more than A, it is obvious that pushing the terminal in the insertion direction will result in an insertion error.

In conventional housing insertion systems, the problem of insertion errors has been solved by interposing a guide between the terminal and the housing to perform the insertion process. The guide is, for example, in the shape of a funnel with a wide entrance and a narrow exit, and has been used to guide a terminal that has been misaligned beyond a permissible range to the entrance of the insertion hole of the housing. However, it is necessary to prepare a variety of such guides depending on the type of terminal, and when the terminal is changed, it is necessary to change the guide, which is complicated. Furthermore, the provision of the guide makes the housing insertion system mechanically complex. Furthermore, if an attempt is made to push the terminal in from an unreasonable position, the conductive wire portion will bend and buckle within the guide. It is desired to realize a housing insertion system that does not rely on guides.

(Summary of the Invention) The present invention has been made from the above-mentioned viewpoint, and its purpose is to realize a housing insertion system that does not rely on guides.

The present invention is directed to a misalignment detection system for use in a housing insertion system.
The positional deviation detection system according to the present invention detects positional deviation in a plane including the insertion direction of an object to be inserted into a housing.

The positional deviation detection system according to the present invention includes means for imaging an object that is stationary along the housing insertion direction from above the periphery in the insertion direction and providing image data, and means for extracting the outline of the object from the image data. , a means for detecting the position of a predetermined feature point with respect to the extracted contour line, and a means for detecting a positional deviation of the object based on the feature point and providing positional deviation information.

(Description of Embodiments) FIG. 5 shows a housing insertion system that is the background of this invention. Shown schematically. The housing insertion system includes a terminal transfer mechanism 11 for transferring the terminals, a housing movement mechanism 12 for moving the housing, a central controller 13 for controlling the operation of the terminal transfer mechanism 11 and the housing movement mechanism 12, and the terminals. The system is comprised of a positional deviation detection system 14 for detecting positional deviations.

Before being brought into the housing insertion system, the wires and terminals are subjected to a predetermined treatment in the processing section 15. The processing in the processing unit 15 is as follows:
For example, it includes a wire cutting process, a coating stripping process, and a terminal crimping process. For example, the electric wire cut to a predetermined length at the electric wire cutting part (not shown) is
It is bent into a U-shape, its both ends are gripped by a gripping mechanism 16, and then transported by an endless chain 17. Subsequently, at a stripper section (also not shown), the coating on the tip of the end of the wire gripped by the gripping mechanism 16 is stripped off by a predetermined length. after that,
The electric wire 2 is brought to the terminal crimping section 18, and the terminal 3 is crimped onto the core wire portion from which the sheathing has been stripped off (step S1 in the figure).

After the processing process is completed, the wires are crimped with terminals.
It is further transported by the endless chain 17 to the terminal transport mechanism 11 part of the housing insertion system. There, the wire 2 is released from the gripping mechanism 16 associated with the endless chain 17 and is replaced by the terminal transfer mechanism 1 of the housing insertion system.
1 (step S2 in the figure).

At this point, the positional shift of the terminal 3, which is crimped to the tip of the electric wire gripped by the gripping mechanism 19,
It is detected by the positional deviation detection system 14. This detection procedure will be explained later. As a result of the detection, if the terminal positional deviation exceeds the permissible range, error information is provided to the central control unit 13. The central controller 13 controls the terminal transfer mechanism 11 and the housing movement mechanism 12 based on the error information, and discards the terminal without performing the insertion process. Discarding may be performed, for example, after the terminal is transferred to an appropriate location by the terminal transfer mechanism 11.

As a result of the detection, if it is found that the positional deviation of the terminal is within the permissible range, the positional deviation detection system 14
gives positional deviation information to the central control device 13. The central control device 13 controls the operations of the terminal transfer mechanism 11 and the housing movement mechanism 12 based on the provided positional deviation information to perform the insertion process (step S3 in the figure).

The terminal transfer mechanism 11 moves the terminal in the direction of the illustrated bidirectional arrow P. Housing moving mechanism 12
moves the housing in the direction of the double arrows Q and R shown and in the direction perpendicular to the plane of the paper. Q
The movement in the direction is performed by moving the cart 23 by the action of the screw 20, and the movement in the R direction and the direction perpendicular to the plane of the paper is performed by the screws 21 and 2, respectively.
This is done by moving the trolley 24 by means of 2.

For insertion into the housing 1, the terminals 3 are transferred to the terminal transfer means 1 on the basis of instructions from the central control unit 13.
1 for a predetermined distance and brought to the front of the housing moving mechanism 12. The housing 1 is now at position A within the housing moving mechanism 12. The central controller 13 gives a movement command to the housing moving mechanism 12 based on the positional deviation information from the positional deviation detection system 14 . Accordingly, the housing 1 is moved by an appropriate distance in the Q direction and in the direction perpendicular to the plane of the paper, and the terminal 3 and the housing insertion hole entrance are positioned. Thereafter, the housing 1 is moved in the R direction from position A to position B based on a movement command from the central control device 13 to the housing moving mechanism 12. In this way, the insertion of the terminal 3 into the housing 1 is completed.

In the above explanation, it is stated that the movement of the terminal 3 and the movement of the housing 1 are performed sequentially.
These will actually be done in parallel. The movement for positioning the terminal 3 and the entrance of the housing insertion hole is relative, and the amount of movement of only the housing 1 may be controlled as described above, or alternatively, only the terminal 3 or both may be controlled. This can also be achieved by appropriately controlling the amount of movement. When inserting, the housing 1 is in the R direction (from A to B)
Instead of moving to the housing 1 side, the terminal 3 may be moved to the housing 1 side. If the housing moving mechanism 12 is constructed so that the housing 1 can be rotated by an appropriate angle within a plane perpendicular to the insertion axis (R direction), it is also possible to correct the rotational positional deviation of the terminal 3. Alternatively, the terminal transfer mechanism 11 may be provided with a similar function, that is, a function capable of rotating the terminals 3 by an appropriate angle, and the rotational position shift of the terminals 3 can be similarly corrected.

Next, detection of positional deviation by the positional deviation detection system 14, which is the background of this invention, will be explained in detail. The positional deviation detection system 14 includes a television camera 25 that images the terminal 3, an image processing section 26 that receives an image signal, processes the image, and provides positional deviation information, and a light source 27.

Now, the terminal 3, which is the object to be imaged by the television camera 25, is inserted in the insertion direction (direction R) at the position S2.
It is stationary along. The light source 27 illuminates the terminal 3 from an appropriate position in front. TV camera 2
5 images the terminal 3 from the front in the insertion direction. The imaging is performed so that the characteristic portion of the outline of the terminal 3 can be sufficiently captured. For example, the illustrated terminal 3 has an external shape as shown in FIG. 1 and consists of two curved parts when viewed from the front.
The television camera 25 is arranged so as to image only one curved portion. It is desirable that the background of the object has uniform density and sufficient contrast with the object.

FIG. 6 is a flowchart schematically showing the operation of the positional deviation detection system 14 of FIG. 5, which is the background of the present invention. This positional deviation detection system 1
Since the operation of No. 4 is substantially the same as the operation of the positional deviation detection system according to the present invention, which will be described later, only a very schematic explanation will be given here.

First, in step S1, an image data signal from the camera is taken into an image memory (not shown) in the image processing device 26 and fixed. Next, in step S2,
A Laplacian filter is applied to the image data to emphasize the edges of the object on the image data. Next, in step S3, the edge-enhanced image data is applied with a threshold filter and converted into binary data indicating whether the density value of each dot of the image data exceeds the threshold value. As a result, as shown in FIG. 7, a contour image of the object is obtained.

Next, in step S4, feature points are extracted from the binary image data and their positions on the screen are determined. For example, as shown in FIG. 7, the feature point is a point P1 where the Y coordinate value (distance from the top of the screen) is the minimum when the screen is scanned in the X-axis and Y-axis directions;
The point P2 may have the maximum value, and the point P3 may have the minimum X coordinate value (distance from the left edge of the screen).
The image processing device 26 calculates the distance a in the Y direction between P1 and P2.
By checking the distance b in the Y direction between P1 and P3, it is determined whether the rotational positional deviation of the terminal is within an allowable range. As shown in Figure 8A,
As the terminal undergoes a leftward rotational displacement, the value of a becomes slightly larger and the value of b becomes significantly larger. Furthermore, as shown in FIG. 8B, as the terminal rotates to the right and shifts its position,
The value of b becomes slightly smaller, and the value of a becomes significantly larger. By utilizing this fact and checking whether the values of a and b are both within predetermined reference values, it is possible to know whether the rotational positional deviation of the terminal is within the permissible range.

If the rotational positional deviation of the terminal is within the allowable range, the amount of deviation of the terminal in the X and Y directions is calculated. This deviation may be determined, for example, between the origin PO located at the center of the screen and the feature point P3. △ in Figure 7
x represents the amount of deviation in the X direction, and Δy represents the amount of deviation in the Y direction. After determining the amount of deviation based on the number of dots on the screen, the image processing device 26 converts this into an actual distance.

Next, proceed to step S5, and the deviation amounts △x, △y
is transmitted to the central control device 13. As a result, the central control device 13 causes the terminal transfer mechanism 1 to perform the insertion process by correcting the positional deviation based on Δx and Δy.
1 and the housing moving mechanism 12. If it is found in step S4 that the rotational position deviation of the terminal is outside the allowable range, △
An error signal is sent to the central controller 13 instead of x, △y.
sent to. As a result, the central control device 13
A command is given to the terminal transfer mechanism 11 and the housing movement mechanism 12 to discard the terminal without inserting the terminal.

As shown in FIG. 9, the positional deviation detection system 14 shown in FIG. 5 detects the deviation of the terminal in the X-Y direction using an image from the front of the terminal. However, since the portion to be photographed is a cut surface of a terminal, there are many unevenness to begin with, and it may be difficult to focus or the illumination light reflection 28 may be irregular, making it difficult to obtain a correct image. Furthermore, there are cases where it is difficult to separate the image and the background due to the influence of reflected light 29 from areas other than the photographed area. In such a case, if the misalignment in the camera optical axis direction (Z direction) overlaps, it will have an even more negative effect.
It is also conceivable that the edges of the object cannot be accurately extracted, making it impossible to detect positional deviations. That is, even though the terminal has a three-dimensional (six degrees of freedom) positional shift, accurate measurement is difficult to be expected if the terminal is photographed from only one direction.

This invention was made against this background, and previously, for example, image processing was performed on an image seen from above, and the deviation in the Z direction, furthermore, the deviation in the X direction, and the rotation in the X-Z plane were detected. This is to detect. If the displacement in the X-Z plane detected in this way is removed in advance by the control system, and then the above-mentioned image processing from the front is performed under optimal conditions, the positional displacement in the X-Y plane can be detected. It can be done easily and accurately.

FIG. 10 is a block diagram schematically showing a preferred embodiment of the positional deviation detection system according to the present invention. The positional deviation detection system according to the present invention includes a television camera 30 that images the terminal 3, a camera control device 31 that controls and processes an image signal, an image processing unit 32 that receives and processes the image signal and provides positional deviation information, and a monitor television 33. , and light source 34
It consists of The image processing section 32 includes an image memory 35 for capturing and fixing image signals from the television camera 30, a memory 36 for pre-storing data necessary for image processing, and a memory 36 for storing and storing image signals from the television camera 30. an arithmetic processing device 37 that executes predetermined arithmetic processing based on the
It consists of a CRT display 38. The terminal 3 is held by the terminal transfer mechanism 11 shown in FIG. 5, for example, and the central control unit 13 is the same as that shown in FIG. Therefore, the central control unit 13 of FIG. 10 is connected to the terminal transfer mechanism 11 and the housing movement mechanism 12 of FIG. 5.

It is now assumed that the terminal 3 is stationary along the insertion direction (direction R), for example, at position S2 in FIG. In this state, as a preprocess for detecting a positional deviation from the front of the terminal by the positional deviation detection system 14 shown in FIG. 5, the positional deviation detection system according to the present invention shown in FIG. 10 is used to detect a positional deviation from above the terminal. The light source 34 illuminates the reflective surface 39 from a suitable position above the terminal. The reflective surface 39 is desirably one that produces diffused reflection in order to make the density of the background uniform and facilitate the detection of positional deviation. Note that instead of the reflective surface 39, a screen 40 may be used as shown in FIG.
In this case as well, the screen is preferably one that scatters and transmits light. The reason why indirect illumination is used in this way is to remove the adverse effects of reflected light and perform more accurate positional deviation detection.

The television camera 30 images the terminal 3 from above. The imaging is performed so that the characteristic portion of the outline of the terminal 3 can be sufficiently captured. For example, the illustrated terminal 3 has an external shape as shown in FIG. 9, and the television camera 30 is arranged to take an image of the cut-off tab portion 41 of the terminal 3. At least while the image data is being loaded into the image memory 35, the terminal 3 must remain stationary.

FIG. 12 is a flowchart schematically showing the operation of the positional deviation detection system shown in FIG. 10, which is a preferred embodiment of the present invention. Operation begins upon receipt of an activation command from central controller 13. Step S6 is in a state of waiting for a startup command, and upon reception of the startup command, the process moves to step S7.

In step S7, the image signal captured by the television camera 30 is taken into the image memory 35. This image signal is a digital multi-gradation image data signal representing the shading of the image, for example f(m,
n). m and n represent dot positions in the image. The image data f(m, n) is stored in the image memory 3 under the write control of the camera control device 31.
5 and is fixed. Note that the image captured by the television camera 30 is transmitted to the camera control device 31.
The image is displayed on a monitor television 33 at all times through which it can be monitored.

Next, the process moves to step S8. In step S8,
The edges of the object on the image data are emphasized and converted into a contour image. This operation is performed as follows. First, the image data f(m, n) taken into the image memory 35 is sequentially transferred to the arithmetic processing unit 3.
7. The arithmetic processing unit 37 applies a Laplacian filter to the image data f(m, n) and converts it into contour image data g ₁ (m, n). That is, the density value at a certain point is replaced with the value of the square of the Laplacian. Expressing this in a formula is as follows.

g ₁ (m, n) = (▽ ² f (m, n)) ² = {f (m, n+
1) +f(m,n-1)+f(m+1,n) +f(m-1,n)-4f(m,n)} ² The maximum value of g ₁ (m, n) is g _1nax (m, n ),
The minimum value is g _1nio (m, n).

Next, the process moves to step S9. In step S9,
By applying a threshold filter to the contour image data g ₁ (m, n), it is possible to determine whether the density value of each dot in g ₁ (m, n) exceeds the threshold value into binary data. A conversion takes place. For example, the average value g _1thr (m, n) of g 1nax (m, n) and _{g 1nio (} m, n) may be selected as the threshold value. Also, other suitable threshold values may be selected. The arithmetic processing unit 37 determines that the value g ₁ (m, n) at a certain point is a threshold value.
When exceeding g _1thr (m, n), the maximum concentration value (3FH)
If it does not exceed the value, replace it with the lowest density value (0). This can be expressed as a formula as follows.

g ₁ (m, n) = 3F (g ₁ (m, n
)>g _1thr (m, n)) 0(g ₁ (m, n) g _1thr (m, n)) The binary data replaced in this way is g ₂
(m, n). Contour image data
The purpose of replacing g ₁ (m, n) with binary data g ₂ (m, n) is to make the contour part of the edge-enhanced contour image data even clearer and to facilitate subsequent processing. be. The contour image obtained in this way is shown in FIG.

Next, the process moves to step S10. Step S10
Then, binary data g ₂ (m,
n) detect the position of the feature point on the screen. The positions of the feature points are determined in advance with respect to the outline of the object, depending on the shape of the object. In this embodiment, the cut-off tab section is used for image processing, and the 13th cut-off tab section is used for image processing.
The figure shows a contour image of the cut-off tab portion that has been binarized as described above. In FIG. 13, b-c-de is the cut-off tab portion. The feature points of this image are point c, point d,
Possible points include point b, point e, and others.

Next, an example of a method for extracting feature points will be described. The x-y coordinates are taken as shown in FIG. 13, and the edge line a-b-c-d-e-f is expressed as y=f(x).
Calculating y'=f'(x) by first differentiation: Between a and b: f'(x)=c Between constant value b and c: f'(x)=c→+∞, -∞→ Between c and change c-d: f'(x)=c Between constant value d-e: f'(x)=c→negative→0→c. In this way, each point b, c, d, e is
It can be detected that f'(x) changes from a constant value c to another value, or from another value to a constant value c.

Also, when calculating y″=f″(x) by second-order differentiation, between a and b: f″(x)=0 between b and c: f″(x)≠0 between c and d: f″(x )=0 Between d and e: f″(x)≠0 Between e and f: f″(x)=0 According to this, each point b, c, d, and e is It can be detected by checking whether x) is 0.

Next, the process moves to step S11. Step S11
Now, b, c, d, detected as described above,
The actual position of the terminal is detected based on the position of point e on the screen. This detection can be done, for example, by setting the origin at one point on the screen (for example, the center point), and then
This may be done by converting the deviations of points d and e from the origin on the screen into actual distances. Data necessary for conversion is stored in memory 36 in advance.
Since a specific point on the screen corresponds to a certain point at the imaging point, by knowing the deviation from the origin, it is possible to know the actual positional deviation of the object. Furthermore, the rotation direction and rotation angle of the terminal can also be determined from the value c of f'(x).

Next, the process moves to step S12. Step S12
Then, the positional deviation information obtained in step S11 is transmitted to the central control device 13. The central control device 13 controls, for example, the gripping mechanism 19 (see FIG. 5) of the terminal transfer mechanism 11 based on the provided positional deviation information, and moves the terminal 3 in the X-Z plane of FIG.
Remove the misalignment. Thereafter, by correcting the positional deviation by imaging from the front of the terminal as described above, it becomes possible to easily and accurately correct the positional deviation in the X-Y plane.

In the above-mentioned embodiment, feature points are extracted by arithmetic processing, but depending on the shape of the object, other methods may be used, such as matching with basic shapes, or moving the screen in the X and Y directions. This may be performed by a method of scanning in the direction. Also, although the image is taken from above the terminal, if only the shift in the Z direction is to be detected, the
For example, it is also possible to take an image from the side of the terminal.
When the positional deviation detection system according to the present invention is used as pre-processing for the positional deviation detection system shown in FIG. 5, the image processing section and the television camera can be used in common. Further, since the positional deviation detection system according to the present invention alone can detect horizontal deviations and rotations, it is believed that this system alone has a wide range of applications.

(Effects of the Invention) As described above, according to the present invention, the positional deviation in a plane including the insertion direction of the object to be inserted into the housing is detected by image processing.
It becomes possible to accurately position the object at a certain point along the insertion direction. In particular, if the positional deviation detection system according to the present invention is used for preprocessing, it becomes possible to easily and accurately detect positional deviations by imaging from the front of the object.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the state before the terminal and housing are inserted, Fig. 2 is an explanatory diagram showing the internal structure of the insertion hole of the housing, and Fig. 3 is a sectional view showing the state of the terminal being inserted into the housing insertion hole. , FIG. 4 is an explanatory diagram showing the state of terminal misalignment, FIG. 5 is a schematic explanatory diagram showing the entire housing insertion system which is the background of this invention, and FIG. 6 is an explanatory diagram of the state of FIG. A flowchart showing the operation of the positional deviation detection system 14, FIGS. 7 and 8 are explanatory diagrams showing the outline of the terminal on the screen, FIG. 9 is a diagram explaining imaging from the front of the terminal, and FIG. A block diagram schematically showing a preferred embodiment of the positional deviation detection system according to the invention, FIG. 11 is an explanatory diagram showing another method of illumination, and FIG. 12 schematically shows the operation of the positional deviation detection system of FIG. 10. Flowchart showing 13th
The figure is an explanatory diagram showing the outline of the cut-off tab portion of the terminal on the screen. In the figure, 1 is a housing, 2 is an electric wire, 3 is a terminal, 11 is a terminal transfer mechanism, 12 is a housing movement mechanism, 13 is a central control device, 14 is a positional deviation detection system which is the background of this invention, 25 and 30 are A television camera, 27 and 34 are light sources, 31 is a camera control device, 35 is an image memory, 36 is a memory, 3
7 indicates arithmetic processing units, respectively.

Claims (1)

[Claims] 1. A system for detecting positional deviation of an object to be inserted into a housing in a plane including the direction of insertion, the system comprising: means for capturing an image from above and providing image data; means for extracting a contour of the object from the image data; and positioning of feature points predetermined with respect to the contour based on the extracted contour. A positional deviation detection system, comprising: means for detecting a positional deviation of the object based on the feature points, and means for providing positional deviation information by detecting a positional deviation of the object based on the feature points. 2. The positional deviation detection system according to claim 1, wherein the means for detecting the position of the feature point includes means for differentiating a function represented by the contour line. 3. The means for extracting the contour line includes: means for emphasizing the edges of the object on the image data; and means for performing threshold discrimination on the edge-enhanced image data and converting it into binary data. A positional deviation detection system according to claim 1. 4. A system for detecting positional deviation of an object to be inserted into a housing in a plane perpendicular to the direction of insertion, which images the object held still along the direction of insertion of the housing from above the periphery of the direction of insertion. means for providing image data; means for extracting a contour of the object from the image data; and means for detecting positions of predetermined feature points on the contour based on the extracted contour. , means for detecting positional deviation in a plane including the insertion direction of the object based on the feature points and providing positional deviation information; and controlling the posture of the object based on the positional deviation information. , a means for removing a positional deviation in a plane including the insertion direction of the object; and a means for removing a positional deviation in a plane perpendicular to the insertion direction of the object from which the positional deviation in the plane including the insertion direction has been removed. A positional deviation detection system comprising: means for detecting.