JPH0732231A - Position detecting device for protrusion - Google Patents

Abstract

PURPOSE:To provide a position detecting device capable of detecting the correct position of a protrusion regardless of the tip part shape of the protrusion and even in the case of no space existing around the protrusion. CONSTITUTION:A position detecting device for a protrusion is provided with a visual sensor 3 disposed on the opposite side to the base 1 side with the tip of a protrusion 2 as a reference, a lighting unit 4 disposed annularly on the visual sensor 3 side so as to irradiate the protrusion 2 and the base 1, and a shading member 8 disposed protruding onto the protrusion 2 side from the lighting unit 4 on the inside of the lighting unit 4 so as to limit the incidence of light from the lighting unit 4 into the vicinity of the tip of the protrusion 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device for visually detecting the position of a protrusion protruding on a base.

[0002]

2. Description of the Related Art Conventionally, in a vehicle assembly factory, for example, an automatic tire assembling work using a robot has been performed. In this case, in order to control the automatic assembling robot, the position of the hub bolts installed in the hub unit is detected by a position detecting device including a CCD (charge coupled device) camera before assembling the tire. .

A position detecting device used for such a purpose has a surface of a base called a disk plate of a hub unit and a hub bolt planted on the base, which is C
An image of the tip of the hub bolt and the surface of the base is captured while being illuminated by the illumination unit attached to the CD camera, and this is transmitted to the image processing apparatus. In the image processing apparatus, the analog waveform corresponding to the brightness of the image is binarized for brightness and darkness so that the portion corresponding to the base is bright and the portion corresponding to the top portion of the hub bolt is dark. Is detected and displayed, and the position data is transmitted to the tire automatic assembly robot to control the robot.

However, when a hub bolt, which is a protrusion whose position is to be detected, is formed by rolling, the end surface of the tip of the protrusion is not flat but has an irregular shape, as shown in the sectional shape of FIG. Therefore, when the position detecting device described above is used, as shown in FIG. 5, an image in which the contrast between the protrusion and the base that is the background is not very clear and which is not a perfect circle can be obtained from the CCD camera. Like Therefore, since it is difficult to binarize the brightness and darkness as it is, conventionally, binarization processing is performed after differentiating the video signal. However, not only time is required for calculation, but also highly accurate position detection is possible. Sometimes it was impossible.

Therefore, for example, in the position detecting device for a protrusion disclosed in Japanese Patent Laid-Open No. 3-209110, a protrusion (hub bolt) protruding from the base is provided so as not to illuminate the tip of the protrusion with illumination light. ) Is arranged in the vicinity of the tip of the projection plate, and a translucent projection plate that restricts the incidence of light on the tip is arranged. The bright and dark pattern is projected on the projection plate, and the bright and dark pattern is projected on the projection plate.
The position of the protrusion is detected by capturing an image with the D camera.

[0006]

However, in the position detecting device for the protrusion described in the above publication, a light-transmitting material that limits the incidence of light onto the tip of the protrusion (hub bolt) is provided. Not only does it have the drawback of complicating the device because the projection plate needs to be placed, but it also requires space for placing the projection plate and the lighting unit. In some cases it was not applicable.

In view of the above-mentioned circumstances, the present invention does not depend on the shape of the tip of the projection whose position is to be detected, and even when there is no space around the projection, It is an object of the present invention to provide a position detecting device for a protrusion capable of accurately detecting a position.

[0008]

SUMMARY OF THE INVENTION A projection position detecting apparatus according to the present invention includes a visual sensor disposed on the side opposite to the base side with respect to the tip of the projection, and the projection and the base. An illumination unit annularly arranged on the side of the visual sensor to irradiate, and an illumination unit disposed inside the illumination unit so as to project toward the protrusion side with respect to the illumination unit and near the tip of the protrusion from the illumination unit. It is characterized by comprising a light shielding member for limiting the incidence of light.

According to one embodiment of the present invention, the protrusion comprises a bolt erected on the base, and a light shielding cylinder is provided as the light shielding member coaxially with the illumination unit.

[0010]

According to the present invention, the illumination unit and the light shielding member are arranged on the visual sensor side coaxially with the visual sensor, and the light shielding member brings the light emitting member and the light shielding member to the vicinity of the tip of the projection whose position is to be detected. Since it is configured to limit the incidence of light from the illumination unit, without being influenced by the shape of the tip of the protrusion whose position is to be detected,
From the visual sensor, it is possible to obtain video data that expresses a clear light and dark pattern to the extent that it does not require binarization and does not necessarily require binarization. Can be increased.

Further, according to the present invention, since the illumination unit and the light blocking member are arranged coaxially with the visual sensor on the visual sensor side, no space is required around the protrusion whose position is to be detected. There is.

Further, according to the present invention, since the position detecting device used in the past can be constructed by simply adding a light shielding member, it is easy to modify the conventional device and the structure is simple. However, it has an excellent effect.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a position detecting device for a protrusion according to an embodiment of the present invention.

This position detecting device is a CCD arranged on the side opposite to the base 1 side with reference to the tip of a hub bolt 2 erected on the base 1 called a disk plate.
It is composed of a (charge coupled device) camera 3 and an illumination unit (ring light) attached to the CCD camera 3 for illuminating the surface 1a of the hub bolt 2 and the base 1 and having an annular light emitting portion.

The CCD camera 3 is provided with a camera body 5 having a CCD image sensor as a visual sensor, a lens portion 6, and a cylindrical hood portion 7. The hood portion 7 has an annular shape outside the hood portion 7. The lighting unit 4 is coaxially attached. This illumination unit 4 has an annular slit 4b for light emission on the end face (lower end face in FIG. 1) of the container 4a containing a large number of optical fibers on the base 1 side.
Is coaxially provided with the CCD camera 3.

Further, in the CCD camera 3, a light shielding tube 8 is attached coaxially with the illumination unit 4 inside the annular illumination unit 4. The end face of the light-shielding tube 8 on the hub bolt 2 side is projected toward the hub bolt 2 side more than the end face of the illumination unit 4 on which the slit 4b is formed, whereby a part of the light emitted from the slit 4b. And the light is blocked by the tip 2a of the hub bolt 2.
It has the function of limiting the incidence on the.

In this embodiment, since the light-shielding cylinder 8 having the above-mentioned functions is attached to the CCD camera 3, the clear brightness as shown in FIG. Image with contrast of CCD
It can be easily obtained from the camera 3. Therefore, it is possible to accurately and quickly detect the position of the hub bolt 2 erected on the base 1. Further, since the illumination unit 4 and the light shielding tube 8 are arranged coaxially with the CCD camera 3 on the CCD camera 3 side, no extra space is required around the hub bolt 2 which is a protrusion whose position is to be detected. There are advantages. Furthermore, according to the present embodiment, the position detecting device which has been conventionally used can be constructed by adding the light-shielding tube 8. Therefore, the conventional device can be easily modified and the structure is simple. Nevertheless, it has an excellent effect.

As shown in FIG. 3, when five hub bolts 2 are erected on the base 1, two CCD cameras 3 each having the above-mentioned illumination unit 4 and light-shielding tube 8 are provided. Is arranged with a predetermined distance D, that is, the two hub bolts 2 and 2 selected every other interval are maintained, and based on the position detection of these two hub bolts 2 and 2, the tire automatic assembly robot is I'm trying to control.

From the above description, the structure of the position detecting device for protrusions according to the present invention and the operation and effects thereof have been clarified. However, the present invention is not limited to detecting the position of the hub bolt,
It is applicable to position detection of various protrusions. In that case, a zoom lens is adopted as the lens portion 6 of the CCD camera 3 in the above embodiment, and the projecting length of the light shielding tube 8 from the end face of the illumination unit 4 can be varied, so that the applicable range is remarkably increased. Can be expanded.

[Brief description of drawings]

FIG. 1 is a side view, partly in section, showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an image obtained from the device of the present invention.

FIG. 3 is a front view of a hub unit to which the device of the present invention is applied.

FIG. 4 is a cross-sectional view showing a tip shape of a hub bolt.

FIG. 5 is a diagram showing an image obtained from a conventional device.

[Explanation of symbols]

 1 Base 2 Hub Bolt (Protrusion) 3 CCD Camera 4 Lighting Unit 5 Camera Body 6 Lens 8 Shading Tube

Claims (2)

[Claims] 1. A position detection device for visually detecting the position of a protrusion protruding on a base, wherein the visual sensor is arranged on the side opposite to the base side with respect to the tip of the protrusion. An annular illumination unit arranged on the side of the visual sensor to illuminate the protrusion and the base; and a protrusion disposed on the inside of the illumination unit so as to protrude toward the protrusion with respect to the illumination unit. A position detecting device for a protrusion, comprising: a light blocking member that restricts the incidence of light from the illumination unit near the tip. 2. The projection according to claim 1, wherein the projection is a bolt erected on the base, and the light blocking member is a light blocking tube arranged coaxially with the lighting unit. Object position detection device.