KR20150097941A

KR20150097941A - Auto-inspection method for reduction gear

Info

Publication number: KR20150097941A
Application number: KR1020140018832A
Authority: KR
Inventors: 박두진; 한월숙
Original assignee: 동명대학교산학협력단; 주식회사 알파로보틱스
Priority date: 2014-02-19
Filing date: 2014-02-19
Publication date: 2015-08-27

Abstract

The present invention relates to a speed reducer automatic inspection method capable of performing the performance of a speed reducer quickly, accurately and automatically. A method for automatically inspecting a speed reducer according to the present invention includes the steps of connecting a test disk having a mark to a driving shaft of a speed reducer, photographing the inspection disk, analyzing the photographed image, Rotating the drive shaft of the speed reducer by a reference angle, photographing the inspection disc after the speed reducer is rotated, analyzing the photographed image to confirm the position of the mark, Measuring an actual rotation angle at which the inspection disc is actually rotated from a position of a mark in a previously photographed image and a position of a mark in an image photographed after the reduction gear rotates; comparing the actual rotation angle and the reference angle And evaluating the performance of the speed reducer.

Description

{Auto-inspection method for reduction gear}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of automatically checking a speed reducer, and more particularly, to a method of automatically checking whether a speed reducer has an error.

The speed reducer is currently used in various industrial fields by adjusting the rotation speed by using two or more gears meshing with each other. Currently, there are many patent applications such as Korean Registered Patent No. 10-0955093 .

However, since the speed reducer is composed of gears which mesh with each other, even if the speed reducer is made precise, in some cases, an error occurs in the gear engagement due to a work error or the like, thereby causing an error in driving the speed reducer. Therefore, after manufacturing a speed reducer, the performance of the speed reducer must be checked.

Accordingly, the present invention proposes a method for quickly and accurately performing the performance of the speed reducer.

Korean Registered Patent No. 10-0955093 (Title of the Invention: Design Method of Precision Reducer and Precision Reducer)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of automatically testing a speed reducer capable of quickly and accurately performing the performance of the speed reducer.

A method for automatically inspecting a speed reducer according to the present invention includes the steps of connecting a test disk having a mark to a driving shaft of a speed reducer, photographing the inspection disk, analyzing the photographed image, Rotating the drive shaft of the speed reducer by a reference angle, photographing the inspection disc after the speed reducer is rotated, analyzing the photographed image to confirm the position of the mark, Measuring an actual rotation angle at which the inspection disc is actually rotated from a position of a mark in a previously photographed image and a position of a mark in an image photographed after the reduction gear rotates; comparing the actual rotation angle and the reference angle And evaluating the performance of the speed reducer.

According to the present invention, the step of analyzing the photographed image may include the steps of removing noise from the photographed original image using an image filter, smoothing the histogram of the noise-removed image, And binarizing the binarized image with a morphology technique.

According to the present invention, it is possible to automatically, quickly and accurately check whether the speed reducer malfunctions.

FIG. 1 is a schematic block diagram of an automatic speed reducer inspection apparatus for implementing a method of automatic gear reducer inspection according to the present invention.
2 is a photograph of the illumination unit shown in Fig.
3 is a plan view of the inspection disc shown in Fig.
4 is a flowchart illustrating a process of analyzing a photographed image according to an exemplary embodiment of the present invention.
5 to 7 are views showing images of respective stages in the image analysis process.
FIG. 8 is a flowchart illustrating a process of inspecting four decelerators using the automatic speed reducer inspection apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of automatically checking a speed reducer according to an embodiment of the present invention will be described with reference to the accompanying drawings, together with a speed reducer automatic inspection apparatus for implementing the method.

FIG. 2 is a photograph of the illuminating unit shown in FIG. 1, FIG. 3 is a plan view of the inspection disc shown in FIG. 1, and FIG. 4 is a flowchart for explaining a process of analyzing a photographed image according to an embodiment of the present invention, and FIGS. 5 to 7 are views showing images of each step in an image analysis process.

1 to 3, an automatic gear-reducer automatic inspection apparatus 100 for implementing a method of automatically testing a speed reducer according to the present embodiment includes a mounting table 10, an inspection disc 20, a transfer rail 30, A vision unit 50, an illumination unit 60, and a control unit 70. [

The mounting table 10 is a place where a speed reducer to be inspected is installed. In this embodiment, the mounting table 10 is formed in a flat plate shape elongated in the left-right direction, and a plurality of through-holes are formed so as to insert a drive shaft of the speed reducer, and the mounting table 10 is provided with a plurality of speed reducers. Particularly, in the case of this embodiment, four different speed reducers are provided as shown in FIG.

The inspection disc 20 is formed in a circular plate shape, and is coupled (connected) to the driving shafts of the respective speed reducers one by one. Then, the inspection disc 20 rotates when the reducer is driven. As will be described later, marks are formed on the inspection disc 20 so as to be discernible when the image is photographed by the vision unit 50. Particularly, in this embodiment, as shown in FIG. 3, eight through holes 21 are formed in the inspection disk 20 at equal angles along the circumferential direction, and the through holes 21 are used as marks. At this time, each of the through holes 21 has a circular shape. On the other hand, the mark may be formed in a form that can be discerned when the image is photographed. Therefore, a sticker may be attached to the top surface of the inspection disc, or a pattern (circular pattern) may be drawn in a form other than the through hole .

The conveying rail 30 is for moving the vision unit 50 to be described later. In this embodiment, the conveying rail 30 is formed to be long in the left-right direction, and is disposed above the mounting base 10. The feed rail 30 is coupled with a feed nut portion 40 that slides along the lengthwise direction of the feed rail (i.e., the left-right direction). The transfer nut unit 40 is provided with a transfer unit 41 (for example, a ball screw or the like) for transferring the object in the vertical direction. At this time, it is preferable that two transfer units are provided. One transfer unit 41 is coupled to the lower end of the transfer nut 40 as shown in FIG. 1, and the other is installed at the center of the transfer nut . However, in Fig. 1, the conveying unit provided at the center of the conveying nut portion is not shown because it is covered by the non-conveying portion.

The vision unit 50 is for photographing the inspection disc 20, and a high-definition digital camera and a lens coupled to the digital camera can be employed as a vision unit. The vision unit 50 is coupled to a conveyance nut unit 40 provided on the conveyance rail 30 and is conveyed (slid) along the conveyance rail 30 in the left and right direction. The conveyance unit That is, in the direction of approaching or separating from the inspection disc 20 by the transfer unit (the transfer unit obscured by the unit).

The illumination unit 60 irradiates the inspection disc 20 with the illumination light when the inspection disc 20 is photographed. In this embodiment, the illumination unit 60 is formed in a circular donut shape as shown in FIG. 2, And the light source 61 of the light source is coupled. The illumination unit 60 is provided below the vision unit 50 (more specifically, between the vision unit and the inspection disc). At this time, the illumination unit 60 is coupled to the transfer unit 41 of the transfer nut, As shown in Fig.

The distance between the illumination unit 60 and the non-electric part (lower end of the lens) 50 is set to about 30 to 80 mm from the inspection disc 20 to the non-electric part Is preferably about 10 mm. Particularly, the non-electric part (direction of the optical axis) should be installed perpendicular to the inspection disc 20.

The control unit 70 includes a communication unit 71, a motion control unit 72, and an analysis unit 73. The communication unit 71 is connected to the vision unit 50 and receives the image photographed by the vision unit 50. [ The communication unit 71 may be an Ethernet card or the like. The motion control unit 72 is connected to a speed reducer (more specifically, a motor installed in the speed reducer), and outputs driving signals to the speed reducer to control the driving. For example, a driving signal is outputted such that the inspection disk connected to the speed reducer rotates at a reference angle, for example, 360 deg., 180 deg.

The analysis unit 73 analyzes the image received by the communication unit 71 and analyzes the performance of the decelerator based on the analyzed image. Hereinafter, an inspection process performed by the analyzer will be described with reference to FIG.

First, the analyzing unit analyzes the photographed image in the initial state (i.e., before the speed reducer is rotated), and confirms the position of the mark (assuming, for example, that the vision unit shoots the first mark in the initial state). Thereafter, the image is photographed in the state where the inspection disc is rotated by the reference angle (for example, 45 DEG), and the position of the mark is confirmed. At this time, if the test disc is rotated exactly by the reference angle, since the second mark is moved to the first mark position, the mark should be positioned at the same position after the rotation. However, if the position of the mark on the image taken by the vision unit after rotation is different from the initial position, this means that an error has occurred in the rotation amount of the inspection disc, and the difference between the position of the first mark and the position of the mark after rotation is calculated In practice, you can calculate the actual rotation angle at which the inspection disc is rotated, and you can calculate the error by comparing this actual rotation angle with the reference angle. That is, the analyzing unit compares the amount of rotation output from the driving signal with the amount of rotation measured as a result of image analysis, and evaluates the performance of the speed reducer (evaluates the error and the degree of error).

Hereinafter, a process of analyzing a photographed image will be described with reference to FIGS. 4 to 7. FIG.

First, the noise is removed from the original image S10 photographed at the non-production section (S20). The noise elimination method uses an averaging filter to remove high frequency component image noise. At this time, the averaging filter can be appropriately selected for the image, and a Gaussian filter is used in the present embodiment. Thereafter, the image is improved by smoothing the histogram of the noise-removed image (S30). Then, only the region of interest is extracted by binarizing the image based on the threshold value (S40), and then post-processing is performed using the morphology technique (S50). If the post-processing is performed in this way, it can be seen that small black dots outside the region of interest (black circle) disappear. Then, the center coordinates are obtained from the remaining black circles (S60).

At this time, the center coordinate of the X axis is d + (f / 2), where f = e - d,

The center coordinate of the Y axis is a + (c / 2), where c = b - a.

FIG. 8 is a flowchart illustrating a process of inspecting four speed reducers using the automatic speed reducer automatic inspection apparatus and the automatic speed reducer inspection method according to the above configuration.

Referring to FIG. 8, when the inspection is first started, the vision unit (vision motion) moves to the origin. In this case, the motor of the first speed reducer is rotated by the selected angle, and at this time, the inspection disk is photographed and analyzed, and the speed reducer Gt; This process is repeated a predetermined number of times. Then, the vision part where the repeated inspection is completed is automatically moved to the second position, and the second speed reducer is inspected (repeated inspection as described above). When the inspection of the second speed reducer is completed, the inspection for the third and fourth speed reducers is sequentially carried out. When the repeated inspection is completed up to the fourth speed reducer, the vision part is moved to the origin again.

On the other hand, if the manual inspection is selected instead of the automatic inspection, the vision unit moves to the position to be inspected (i.e., the position of the manually selected speed reducer), and then performs the inspection only for the speed reducer. When the inspection is completed, the vision is moved to the origin and the inspection is terminated.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, performance evaluation of a speed reducer can be performed automatically, quickly, and accurately, and automatic testing of a plurality of speed reducers can be performed.

In addition, since the non-electric part and the illuminating part can be elevably installed to adjust the distance from the inspection disk, the position of the non-electric part and the illumination part can be appropriately changed according to the inspection conditions (ambient brightness, .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

100 ... Reducer automatic inspection system
10 ... Mounting base 20 ... Inspection disk
30 ... Feed rail 40 ... Feed nut part
41 ... transfer unit 50 ... vision unit
60 ... illumination unit 70 ... control unit

Claims

Connecting a test disk, which is formed in a flat plate shape and on which a mark is displayed, to a drive shaft of the speed reducer,
Photographing the inspection disc, analyzing the photographed image to confirm the position of the mark,
Rotating the drive shaft of the speed reducer by a reference angle;
Photographing the inspection disc after the speed reducer is rotated, analyzing the photographed image to confirm the position of the mark,
Measuring an actual rotation angle at which the inspection disc is actually rotated from a position of a mark in an image captured before the speed reducer rotates and a position of a mark in an image captured after the speed reducer rotates; And evaluating the performance of the speed reducer by comparing the reference angles.

The method according to claim 1,
Wherein the step of analyzing the captured image comprises:
Removing noise from the photographed original image using an image filter,
Smoothing a histogram of the noise-removed image,
Binarizing the smoothed image based on a threshold value;
And post-processing the binarized image by a morphology technique.