WO2020170531A1

WO2020170531A1 - Inspection device and inspection method

Info

Publication number: WO2020170531A1
Application number: PCT/JP2019/045795
Authority: WO
Inventors: 努作山
Original assignee: 株式会社Ｓｃｒｅｅｎホールディングス
Priority date: 2019-02-22
Filing date: 2019-11-22
Publication date: 2020-08-27
Also published as: JP7161956B2; TW202043752A; JP2020134402A

Abstract

In order to inspect, with a high inspection efficiency, a workpiece serving as an inspection target, the present invention is provided with: a line imaging unit that acquires a line image by imaging, at a workpiece holding position, a linear region radially extending from a portion positioned on a symmetric axis in the workpiece held by a workpiece holding unit; a determination unit that determines, before the movement of the workpiece from the workpiece holding position to an inspection position, whether the workpiece held by the workpiece holding unit is an inspection target or not on the basis of the line image acquired by the line imaging unit; and a inspection control unit that restricts the movement and inspection of the workpiece held by the workpiece holding unit toward the inspection position when the workpiece held by the workpiece holding unit is not determined to be an inspection target.

Description

Inspection device and inspection method

The present invention relates to an inspection device and an inspection method for inspecting the appearance of a work based on an image obtained by imaging a work having a rotationally symmetric outer peripheral portion around an axis of symmetry.

The disclosures in the specification, drawings and claims of the following Japanese application are incorporated herein by reference in their entirety:
Japanese Patent Application 2019-030650 (filed on February 22, 2019).

As an apparatus for inspecting the appearance of a work rotationally symmetrical about the axis of symmetry, for example, the inspection apparatus described in Patent Document 1 is known. In this inspection apparatus, the position of the work on the holding table is corrected before the work held by the holding table is imaged and inspected by the imaging unit for inspection. More specifically, on the basis of an image of the work obtained by imaging the work held by the holding table around the rotation axis with the core deviation detection imaging unit, the deviation of the axis of symmetry with respect to the rotation axis, that is, the core Seeking a gap. Then, in parallel with moving the holding table holding the work to the inspection position, the position of the work is corrected by the holding table. After that, while rotating the work held by the holding table at the inspection position around the rotation axis, the inspection image pickup unit captures an image, acquires an image, and performs inspection based on the image.

Japanese Patent Laid-Open No. 2018-151243

In the apparatus described in Patent Document 1, for example, a work whose size and shape are different from the inspection target (hereinafter referred to as “non-inspection target work”) may be loaded and set on the holding table. There is no means for detecting non-target work. Therefore, the misalignment detection, the position correction, the work movement, and the work inspection may be performed on the non-inspection target work. In this way, wasteful inspection is performed, which is one of the factors leading to a decrease in inspection efficiency.

Further, in order to perform the misalignment detection, the position correction, the work movement, and the work inspection, it is necessary to move the holding table holding the work, and the following problems occur to further lower the inspection efficiency. There was also. For example, although a non-inspection target work can be set and held in the holding table, the non-inspection target work differs from the original inspection target work in terms of size, shape, etc. The work holding force may not be sufficient. When the holding table moves without having a sufficient holding force in this way, the non-inspection target work may drop off from the holding table. In this case, it is necessary to suspend the inspection until the device is recovered and the device is restored, and the reduction of the inspection efficiency is unavoidable.

The present invention has been made in view of the above problems, and an object thereof is to provide an inspection device and an inspection method capable of inspecting a workpiece to be inspected with high inspection efficiency.

One aspect of the present invention is a workpiece to be inspected by holding a workpiece having a rotationally symmetric outer peripheral portion around an axis of symmetry at a workpiece holding position by the workpiece holding unit and then moving the workpiece held by the workpiece holding unit to an inspection position. An inspection device, a line image capturing unit that captures a line image by capturing an image of a linear region that extends in a radial direction from a site located on the axis of symmetry of the workpiece held by the workpiece holding unit, Prior to the movement of the work from the work holding position to the inspection position, a determination unit that determines whether the work held by the work holding unit is an inspection target based on the line image acquired by the line imaging unit, When the determination unit determines that the work held by the work holding unit is not the inspection target, the inspection control unit that restricts the movement of the work held by the work holding unit to the inspection position and the inspection is provided. I am trying.

Another aspect of the present invention is an inspection method, comprising a work holding step of holding a work having a rotationally symmetric outer peripheral portion about a symmetry axis by a work holding portion at the work holding position, and a work holding position. An image acquisition step of acquiring a line image by imaging a linear region extending in the radial direction from a portion of the work held by the holding unit on the axis of symmetry, and the work being held by the work holding unit based on the line image. A determination process for determining whether or not the work is an inspection target, and when the determination process determines that the work is an inspection target, the work held by the work holding unit is moved to the inspection position for inspection. When it is determined that the workpiece is not the inspection target, the movement of the workpiece held by the workpiece holder to the inspection position and the inspection are restricted.

In the invention thus configured, the line image of the work held in the work holding unit is acquired. Then, based on the line image, it is determined whether or not the work is an inspection target. When it is determined that the workpiece is not the inspection target, movement of the workpiece to the inspection position and inspection are restricted. As a result, only the work to be inspected is moved to the inspection position and inspected.

As described above, according to the present invention, while the inspection of the non-inspection target work is regulated, only the work to be inspected is inspected, so that unnecessary inspection is eliminated and high inspection efficiency is achieved. Is obtained. Further, when the work held in the work holding unit is out of the inspection target, movement of the work from the work holding position to the inspection position is regulated, so that the work is dropped from the work holding unit during the movement. It is possible to prevent interruption of the required inspection and ensure high inspection efficiency.

The plurality of constituent elements of each aspect of the present invention described above are not all indispensable, in order to solve a part or all of the above problems, or part or all of the effects described in the present specification. In order to achieve the above, it is possible to appropriately change or delete a part of the plurality of constituent elements, replace it with another constituent element, or partially delete the limited content. In addition, in order to solve some or all of the above problems, or to achieve some or all of the effects described in the present specification, the technical features included in one aspect of the present invention described above. Part or all of the technical features included in other aspects of the present invention described above may be combined with each other to form an independent form of the present invention.

It is a figure which shows the whole structure of one Embodiment of the inspection apparatus which concerns on this invention. It is a block diagram which shows the electric constitution of the inspection apparatus shown in FIG. It is a perspective view which shows the structure of a work holding unit. 3 is a flowchart showing a work inspection operation by the inspection device shown in FIG. 1. It is a graph which shows the evaluation value of the surface side template and each line image. It is a graph which shows the evaluation value of a back side template and each line image.

FIG. 1 is a diagram showing the overall configuration of an embodiment of an inspection device according to the present invention. 2 is a block diagram showing an electrical configuration of the inspection device shown in FIG. The inspection apparatus 100 is an apparatus for inspecting the external appearance of a work W having a peripheral portion in which a convex portion and a concave portion are cyclically and repeatedly provided in a rotationally symmetric shape around a symmetry axis, such as a gear or an impeller. It has a loading unit 1, a work holding unit 2, an imaging unit 3, an unloading unit 4, and a control unit 5. Note that, here, the work W is a mechanical component in which a gear Wb is provided on an upper portion of a shaft portion Wa as shown in FIG. 1, and is formed by forging or casting, for example. After the parts are manufactured, the work W is transferred to the loading unit 1 by an external transfer robot or an operator.

The loading unit 1 is provided with a work storage unit (not shown) such as a table or stocker. When the work W is temporarily accommodated in the work accommodating portion by an external transfer robot or the like, the work detection sensor 11 (FIG. 2) provided in the work accommodating portion detects the work W and sends a signal to that effect to the device. It transmits to the control unit 5 which controls the whole. Further, the loading unit 1 is provided with a loader 12 (FIG. 2), which receives an uninspected work W accommodated in the work accommodating portion in response to an operation command from the control unit 5 and receives the work holding unit 2 Transport to.

FIG. 3 is a perspective view showing the structure of the work holding unit. The work holding unit 2 is equipped with holding tables 21A and 21B that hold the work W conveyed by the loader 12. The holding tables 21A and 21B have the same configuration, and can hold and hold a part of the shaft portion Wa of the work W in a posture in which the gear Wb is in the horizontal state. Hereinafter, the configuration of the holding table 21A will be described with reference to FIG. 3, while the holding table 21B has the same configuration as the holding table 21A, so the holding table 21B is denoted by the same reference numeral and description thereof will be omitted.

In the holding table 21A, as shown in FIG. 3, a chuck mechanism 22, a horizontal positioning mechanism 23, a rotating mechanism 24, and a vertical positioning mechanism 25 are vertically stacked. The chuck mechanism 22 has movable members 221 to 223 that are substantially L-shaped in a side view, and a moving portion 224 that moves the movable members 221 to 223 in a radial interlocking manner in response to a movement command from the control unit 5. ing. A projecting member 225 is projectingly provided on the upper end surface of each of the movable members 221 to 223, and the upper end surface and the projecting member 225 can engage with the step portion of the shaft portion Wa. Therefore, the moving unit 224 moves the movable members 221 to 223 close to each other in response to a gripping command from the control unit 5, so that the workpiece W is aligned while the central axis of the chuck mechanism 22 and the shaft center of the shaft unit Wa are aligned. Can be held. On the other hand, the moving unit 224 moves the movable members 221 to 223 away from each other in response to a release command from the control unit 5, thereby loading the uninspected work W by the loading unit 1 and the tested work W by the unloading unit 4. It becomes possible to unload.

The chuck mechanism 22 configured in this way is supported by the horizontal positioning mechanism 23. The horizontal positioning mechanism 23 has a so-called XY table that moves the horizontal positioning mechanism 23 in directions orthogonal to each other in the horizontal direction. Therefore, the XY table is driven according to the movement command from the control unit 5, and the chuck mechanism 22 can be positioned with high accuracy on the horizontal plane. As the XY table, a combination of a motor and a ball screw mechanism, a combination of two linear motors that are orthogonal to each other in the horizontal direction, or the like can be used.

The rotating mechanism 24 has a motor 241. The rotation shaft of the motor 241 is extended vertically upward, and the horizontal positioning mechanism 23 is connected to the upper end portion thereof. Therefore, when a rotation command is given from the control unit 5, the motor 241 is operated to integrally integrate the horizontal positioning mechanism 23, the chuck mechanism 22, and the work W gripped by the chuck mechanism 22 around the rotation axis of the motor 241. Rotate.

Here, in the present embodiment, the horizontal positioning mechanism 23 is provided between the chuck mechanism 22 and the rotation mechanism 24, but the technical significance thereof is the central axis of the chuck mechanism 22 and the work W gripped by the chuck mechanism 22. The relative positional relationship between the symmetry axis of the gear Wb and the rotation axis of the motor 241 can be adjusted by the horizontal positioning mechanism 23. That is, by making the center axis of the chuck mechanism 22 and the rotation axis of the motor 241 coincide with each other, the work W gripped by the chuck mechanism 22 can be rotated around the shaft portion Wa. However, when the axis of symmetry of the gear Wb is off the shaft portion Wa, the motor 241 is misaligned and the gear Wb is eccentrically rotated. Therefore, the horizontal positioning mechanism 23 is provided and driven so as to correct the deviation amount and the deviation direction, so that the axis of symmetry of the gear Wb and the rotation axis of the motor 241 can be aligned. As a result, the image of the gear Wb by the imaging unit 3 can be captured with high accuracy, and the inspection accuracy of the work W can be improved.

The vertical positioning mechanism 25 includes a holding plate 251 for holding the motor 241, a base plate 252 arranged below the motor 241, four connecting pins 253 for connecting the holding plate 251 and the base plate 252, and the base plate 252. And an elevating part 254 that elevates and lowers in the direction. The elevating part 254 moves the rotating mechanism 24, the horizontal positioning mechanism 23, and the chuck mechanism 22 integrally in the vertical direction by elevating the base plate 252 according to the elevating command from the control unit 5, and the pre-alignment position described next. It is possible to optimize the height position of the work W at the PA and the inspection position PI (corresponding to an example of the “work holding position” of the present invention).

As shown in FIG. 3, the holding tables 21A and 21B thus configured are fixed on the support plate 261 with a certain distance therebetween. The support plate 261 is supported by the turning drive unit 262 at an intermediate position between the holding tables 21A and 21B. The turning drive unit 262 can turn the support plate 261 by 180 degrees around a turning axis AX1 extending in the vertical direction in response to a turning command from the control unit 5, and as shown in FIG. It is possible to switch between a first position located at the pre-alignment position PA and the inspection position PI, and a second position where the holding tables 21A and 21B are located at the inspection position PI and the pre-alignment position PA, respectively. For example, while the pre-alignment process is performed on the work W held by the holding table 21A located at the pre-alignment position PA, the turning drive unit 262 switches from the first position to the second position, whereby the holding table 21A is moved. Shifts from the pre-alignment position PA to the inspection position PI, and the pre-aligned workpiece W can be positioned at the inspection position PI. Further, after finishing the inspection of the work W, the holding table 21A shifts from the inspection position PI to the pre-alignment position PA by turning in the opposite direction, and the inspection-processed work W is positioned at the pre-alignment position PA. You can As described above, in the present embodiment, the position switching mechanism 26 that switches the position of the work W is configured by the support plate 261 and the turning drive unit 262.

The pre-alignment position PA is a position for performing the pre-alignment process as described above, and also a position for determining whether or not the work W held by the work holding unit 2 is an inspection target, and is positioned at the pre-alignment position PA. The alignment camera 27 is arranged above the held table 21A (or 21B). As shown in FIG. 3, the alignment camera 27 is arranged on the side opposite to the motor 241 with respect to the work W, that is, on the upper side of the work W, and extends outward in the radial direction with respect to the symmetry axis AX2 of the work W. It has a line sensor 271 and can acquire two types of images. That is, the linear region (dotted region in FIG. 3) Wc that extends in the radial direction from the portion of the upper surface of the work W located on the symmetry axis AX2 while the work W is stationary at the pre-alignment position PA is imaged. The line image can be acquired. Further, while the work W is being rotated, the upper surface of the work W can be imaged by the line sensor 271. By rotating the work W at least once, a convex portion (tooth end) formed on the outer peripheral portion of the gear Wb. And a two-dimensional image including all the concave portions (roots) is obtained.

Although not shown in FIG. 3, an alignment illumination unit 28 (FIG. 2) is provided for illuminating the work W held on the holding table 21A (or 21B) to perform the alignment process favorably. Has been. Therefore, when the line image of the linear region Wc is acquired, the rotation of the work W by the rotation mechanism 24 is stopped, and when the two-dimensional image of the upper surface of the work W is acquired, the work W is rotated by the rotation mechanism 24 and the alignment illumination unit is used. The work W can be imaged by the alignment camera 27 while the work W is illuminated by 28. Then, the image data of the linear region Wc of the work W is sent to the control unit 5 and it is determined whether or not the work W held by the work holding unit 2 is an inspection target. On the other hand, the image data of the upper surface of the work W is sent to the control unit 5 to correct the misalignment so that the symmetry axis of the gear Wb and the rotation axis of the motor 241 coincide with each other, that is, the pre-alignment process is executed.

On the other hand, the inspection position PI is a position where inspection processing is performed, and the imaging unit 3 is arranged above the holding table 21A (or 21B) positioned at the inspection position PI. At this inspection position PI, the work W can be imaged by the imaging unit 3 while rotating the work W in a state where the axis of symmetry of the gear Wb and the rotation axis of the motor 241 coincide. Then, the image data of the work W is sent to the control unit 5, and the inspection process for inspecting the gear Wb for the presence of scratches or defects is executed.

The image pickup unit 3 has a plurality of inspection cameras 31 and a plurality of inspection illumination units 32, as shown in FIG. In this imaging unit 3, a plurality of inspection illumination units 32 are arranged so as to illuminate the work W held on the holding table 21A (or 21B) positioned at the inspection position PI from various directions. Then, the work W can be rotated by the rotating mechanism 24, and the work W can be imaged from various directions by the plurality of inspection cameras 31 while the work W is illuminated by the inspection illumination unit 32. These plural image data are sent to the control unit 5, and the control unit 5 inspects the work W.

The holding table 21A (or 21B) holding the workpiece W thus inspected is shifted from the inspection position PI to the pre-alignment position PA by the position switching mechanism 26 as described above. Then, the unloading unit 4 carries out the inspected work W from the holding table 21A (or 21B). The unloading unit 4 is basically the same as the loading unit 1. In other words, the unloading unit 4 has a work accommodating portion (not shown) for temporarily accommodating the inspected work W, the work detection sensor 41 (FIG. 2) and the unloader 42 (FIG. 2), and the control unit. The inspected work W is conveyed from the holding table 21A (or 21B) to the work accommodating portion in accordance with the operation command from 5.

As shown in FIG. 2, the control unit 5 has a well-known CPU (Central Processing Unit) that executes logical operations, a ROM (Read Only Memory) that stores initial settings, and various data that is being operated by the device. It is composed of a RAM (Random Access Memory), etc. that stores information in a memory. The control unit 5 functionally includes an arithmetic processing unit 51, a storage unit 52, a drive control unit 53, an external input/output unit 54, an image processing unit 55, and an illumination control unit 56.

The drive control unit 53 controls the drive of the drive mechanism provided in each unit of the apparatus, such as the loader 12 and the chuck mechanism 22. The external input/output unit 54 inputs signals from various sensors provided in each unit of the apparatus, and outputs signals to various actuators provided in each unit of the apparatus. The image processing unit 55 takes in image data from the alignment camera 27 and the inspection camera 31, and performs image processing such as binarization. The illumination control unit 56 controls turning on and off of the alignment illumination unit 28 and the inspection illumination unit 32.

The arithmetic processing unit 51 has an arithmetic function, and will be described below by controlling the drive control unit 53, the image processing unit 55, the illumination control unit 56, and the like according to the program 521 stored in the storage unit 52. Execute a series of processing. As a result, the arithmetic processing unit 51 serves as the determination unit 511 that determines whether or not the workpiece W is the inspection target based on the line image of the linear region Wc based on the determination reference information 522 stored in advance in the storage unit 52. Function. Further, the arithmetic processing unit 51 also functions as a center deviation detection unit 512 that detects a center deviation of the work W with respect to the motor 241 based on the two-dimensional image of the upper surface of the work W. Further, the arithmetic processing unit 51 also functions as an inspection control unit 513 that moves the work W determined as the inspection target to the inspection position PI and then inspects the work W.

Reference numeral 6 in FIG. 2 is a display unit that functions as an interface with the operator, has a function of displaying the operation state of the inspection apparatus 100, which is connected to the control unit 5, and is also configured by a touch panel to input from the operator. It also has a function as an input terminal for accepting. Further, the present invention is not limited to this configuration, and a display device for displaying the operation state and an input terminal such as a keyboard and a mouse may be adopted.

FIG. 4 is a flowchart showing the inspection operation of the work by the inspection apparatus shown in FIG. In this inspection apparatus 100, the arithmetic processing unit 51 controls each unit of the apparatus according to an inspection program stored in advance in the storage unit 52 of the control unit 5 to execute the following operations. Here, focusing on one work W, various operations executed for the work W will be described. In the control unit 5, the work W does not exist on the holding table 21A located at the pre-alignment position PA, and the work detection sensor 11 stores the uninspected work W in the work storage portion of the loading unit 1. When the confirmation is made, loading of the work W on the holding table 21A is started (step S1). In this loading process, the loader 12 grips the uninspected work W in the work accommodating portion and conveys it from the loading unit 1 to the holding table 21A. In the present embodiment, in order to smoothly perform the loading process and the subsequent misalignment detection process, the central axis of the chuck mechanism 22 and the motor 241 are moved by the horizontal positioning mechanism 23 before the work W is transferred to the holding table 21A. And the three movable members 221 to 223 are separated from each other to prepare for receiving the work W.

When the work W is conveyed to the holding table 21A by the loader 12, the chuck mechanism 22 moves the three movable members 221 to 223 close to each other to sandwich a part of the shaft Wa of the work W, as described above. The work W is gripped (work holding process). At this time, if the work W is an inspection target, the work W is firmly gripped by the chuck mechanism 22 and held by the work holding unit 2 with a sufficient holding force. On the other hand, if the work W is not the inspection target, the work W is gripped by the chuck mechanism 22, but the holding force is not sufficient, and the work W may fall off from the work holding unit 2 when the work W rotates or moves.

Therefore, in the present embodiment, the control unit 5 stops the rotation and movement of the work W, that is, the pre-alignment, before executing a series of operations (deviation detection, position correction, work movement and inspection) described later. The work W located at the position PA is stopped. Then, the alignment illumination unit 28 (FIG. 2) illuminates the work W for a certain period of time in the still state, and the alignment camera 27 acquires a line image (step S2: image acquisition step). It is determined whether the work W is an inspection target (step S3: determination step).

In the present embodiment, the above determination is template matching, that is, the evaluation value indicating the degree of similarity between the reference template and the line image is obtained by Normalized Cross-Correlation (NCC). In the normalized cross-correlation, the closer the evaluation value is to “1”, the more similar the line image to the template, that is, the higher the probability that the work W is the inspection target. Therefore, the evaluation value is compared with the determination reference information 522 stored in the storage unit 52 to determine whether or not the work W is an inspection target. When the normalized cross-correlation is used, the determination criterion information 522 is set to a value larger than zero and smaller than 1, but what value to set is closely related to the determination accuracy. Therefore, it is desirable to set the judgment criterion information 522 after performing verification using a plurality of samples.

In this embodiment, the criterion information 522 is set as follows. First, the front surface and the back surface of the workpiece W to be inspected are imaged by the alignment camera 27, and the line images obtained by them are acquired as a front surface side template and a back surface side template, respectively. On the other hand, in addition to that, 176 workpieces W to be inspected are prepared, the front surface and the back surface of each workpiece W are imaged by the alignment camera 27, and the line images obtained by them are respectively the front surface side line image and the back surface side line image. To get as. Then, using the normalized cross-correlation:-Evaluation value between the front-side template and each front-side line image... Front/front NCC score-Evaluation value between front-side template and each back-side line image-Front/back NCC score I asked. A plot of them is the graph shown in FIG. Also, using normalized cross-correlation:-Evaluation value between backside template and each backside line image... Backside/backside NCC score-Evaluation value between backside template and each frontside line image-Backside/front NCC score I asked. A plot of these is the graph shown in FIG. As is clear from these drawings, the evaluation value is below 0.8 when the work W to be inspected is not properly held on the work holding unit 2, and the work not to be inspected is It is predicted that the evaluation value will certainly fall below 0.8 even when the work holding unit 2 holds the work. Therefore, in the present embodiment, the determination criterion information 522 is set to “0.8” based on the verification experiment shown in FIGS. 5 and 6, and when the evaluation value is 0.8 or more, the work holding unit 2 holds it. The control unit 5 determines that the workpiece W being processed is an inspection target, but is not an inspection target when the evaluation value is less than 0.8.

Return to Figure 4 and continue the explanation. When it is determined in step S3 that the work W is not the inspection target, that is, when the determination is “NO”, the control unit 5 displays that the work W held by the work holding unit 2 is not the inspection target while maintaining the stationary state of the work W. It is displayed on the unit 6 and the inspection is interrupted (step S4).

On the other hand, when it is confirmed that the work W is the inspection target (“YES” in step S3), the work W is inspected in the same manner as the device described in Patent Document 1. That is, the alignment illumination unit 28 (FIG. 2) illuminates the uninspected work W, and the alignment camera 27 images the gear Wb while rotating the uninspected work W by the motor 241 of the holding table 21A to obtain a two-dimensional image. To do. The image data of this two-dimensional image is stored in the storage unit 52 (step S5).

After the completion of this imaging, the turning drive unit 262 switches from the first position to the second position. That is, the turning drive unit 262 turns the support plate 261 about the turning axis AX1 by 180°, whereby the holding table 21A holding the uninspected work W moves from the pre-alignment position PA to the inspection position PI and the elevating unit 254. The work W is moved to a height position where the image pickup unit 3 can pick up an image (step S6).

Further, in the present embodiment, in parallel with the above movement, the image data of the work W is read from the storage unit 52, and the center deviation of the work W with respect to the rotation mechanism 24 (motor 241) (in the present embodiment, the deviation amount and the deviation direction). (Corresponding to information including and) is detected (step S7), and subsequently, misalignment correction in the holding table 21A is performed (step S8). In this misalignment correction, the chuck mechanism 22 is moved by the horizontal positioning mechanism 23 so as to eliminate the misalignment detected in step S7. As a result, the symmetry axis of the gear Wb and the rotation axis of the motor 241 coincide with each other at or before the holding table 21A reaches the inspection position PI, and the workpiece imaging step (step S9) can be started immediately.

In this step S9, the rotation mechanism 24 of the holding table 21A positioned at the inspection position PI operates to start the work rotation. At this time, the work W held by the holding table 21A is in the so-called centering state in which the above-mentioned center misalignment is corrected, and rotates about the symmetry axis AX2. In addition, in response to the rotation, the plurality of inspection illumination units 32 are turned on to illuminate the rotating work W from a plurality of directions.

Thus, while the workpiece W is being rotated and illuminated, the plurality of inspection cameras 31 image the workpiece W from various directions, and image data of the image of the workpiece W from a plurality of directions (hereinafter referred to as “work image”). Is transmitted to the control unit 5. On the other hand, the control unit 5 stores the image data in the storage unit 52, and inspects the work W based on the image data at the following timing.

After such an image is acquired, the rotation of the work is stopped in the holding table 21A, and the inspection illumination unit 32 is turned off in the imaging unit 3. Further, the turning drive unit 262 turns the support plate 261 180° about the turning axis AX1 so that the holding table 21A moves from the inspection position PI to the pre-alignment position PA while holding the inspected work W and moves up and down. The work W is moved to the original height position by the part 254 (step S10). In parallel with the movement of the work W, the control unit 5 reads out the image data from the storage unit 52, determines whether or not the gear Wb has a scratch or a defect on the basis of the work image, and stores it in the holding table 21A. A work inspection is performed on the held work W (step S11).

The work W returned to the pre-alignment position PA is gripped by the unloader 42, and then transferred from the holding table 21A to the unloader 42 by releasing the grip by the movable members 221 to 223. Then, the unloader 42 conveys the work W to the unloading unit 4 and conveys it to the work accommodating portion (not shown) (step S12). The series of steps (steps S1 to S12) described above are alternately repeated by the holding tables 21A and 21B.

As described above, in the present embodiment, the line image of the work W in the stationary state held by the work holding unit 2 is acquired, and it is determined whether or not the work W is the inspection target based on the line image. There is. Then, only the determined work W that is the inspection target is inspected. For this reason, it is possible to regulate the inspection of the work that is not the inspection target and inspect the work W with high inspection efficiency. By carrying out such a regulation, it is possible to reliably prevent the non-inspection target work from being moved from the pre-alignment position PA (work holding position) to the inspection position PI, and the non-inspection target work is held during the movement. It is possible to prevent the unit 2 from falling off, prevent the inspection from being interrupted due to the drop, and ensure high inspection efficiency.

Further, since the alignment camera 27 used for detecting the misalignment is diverted to determine whether or not the work W is an inspection target, the following operational effects can be obtained. In order to add a function of determining whether or not the work W is an inspection target to the conventional apparatus, for example, a photoelectric sensor for detecting the work W is added, and the work W is kept in a posture specified at a specific position. May be detected by a photoelectric sensor, and the above determination may be performed based on the output from the photoelectric sensor. However, when adopting such a configuration, not only the addition of the photoelectric sensor but also the adjustment for each shape of the work W is necessary, and it is difficult to cope with many kinds. Moreover, the above determination becomes difficult because the work position is slightly displaced from the specific position or the work posture is slightly displaced from the designated position. On the other hand, according to the present embodiment, the above determination can be performed without performing hardware modification or adjustment on the conventional device. Further, it is possible to deal with many kinds by setting the judgment reference information 522 individually for each kind in advance. Further, even if the position or orientation of the work W is deviated, it is possible to make the above determination as it is, and it is possible to make the above determination by performing image correction even if the deviation amount is large.

In this way, the work holding unit 2 in this embodiment corresponds to an example of the “work holding unit” of the present invention. Further, the alignment camera 27 corresponds to an example of the “line image pickup section” in the present invention.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the present invention is applied to the work holding device that holds the work W having the gear Wb and the inspection device equipped with the device, but the type of the work W is not limited to this. However, the "workpiece" of the present invention includes all work pieces having an outer peripheral portion that is rotationally symmetrical about the axis of symmetry.

Further, in the above embodiment, the work W is held by the three movable members 221 to 223, but the work W may be held by two or four or more movable members. Good.

Further, in the above-described embodiment, the present invention is applied to the inspection device 100 that detects the misalignment by alternately arranging the two holding tables 21A and 21B at the pre-alignment position PA, but a single device or three or more devices is used. The present invention can be applied to an inspection device having a holding table.

In the above embodiment, the pre-alignment position PA is the “work holding position” of the present invention, but other positions (except the inspection position PI) may be set as the “work holding position”.

Further, in the above-described embodiment, the determination of whether or not the work W is the inspection target is performed by using the normalized cross-correlation, but the determination may be performed by a method other than this. For example, SSD (Sum of Squared Difference), SAD (Sum of Absolute Difference), etc. may be used as template matching.

The invention has been described above with reference to the specific embodiments, but this description is not intended to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description of the invention. Therefore, the appended claims are considered to cover such variations or embodiments without departing from the true scope of the invention.

The present invention can be applied to general inspection devices and inspection methods for inspecting the external appearance of a work based on an image obtained by imaging a work having a rotationally symmetric outer peripheral portion around the axis of symmetry.

2... Work holding unit (work holding unit)
5... Control unit (determination unit, inspection control unit, misalignment detection unit)
24... Rotation mechanism 27... Alignment camera (line imaging unit)
511... Judgment unit 512... Core misalignment detection unit 513... Inspection control unit AX2... Symmetry axis PA... Pre-alignment position (work holding position)
PI...Inspection position W...Work Wc...Linear area

Claims

An inspection device for inspecting a workpiece having a rotationally symmetric outer peripheral portion about a symmetry axis by moving the workpiece held by the workpiece holding portion to an inspection position after holding the workpiece by the workpiece holding portion at the workpiece holding position,
At the work holding position, a line imaging unit that acquires a line image by imaging a linear region that extends in a radial direction from a portion of the work held by the work holding unit that is located on the axis of symmetry,
Whether the work held in the work holding unit is an inspection target based on the line image acquired by the line imaging unit prior to the movement of the work from the work holding position to the inspection position. A determination unit for determining
When it is determined by the determination unit that the work held in the work holding unit is not an inspection target, an inspection control unit that regulates movement and inspection of the work held in the work holding unit to the inspection position. ,
An inspection apparatus comprising:
The inspection apparatus according to claim 1, wherein
The work holding unit has a rotation mechanism that rotates the work around a rotation axis,
An inspection apparatus in which the determination unit makes a determination based on the line image acquired by the line imaging unit in a state where the rotation of the work by the rotation mechanism is stopped.
The inspection apparatus according to claim 2, wherein
Based on a two-dimensional image obtained by imaging the work rotated by the rotation mechanism at the work holding position by the line imaging unit prior to the movement of the work from the work holding position to the inspection position. Further comprising a core misalignment detection unit for detecting misalignment of the work with respect to the rotating mechanism,
Acquisition of the line image by the line imaging unit is performed before acquisition of the two-dimensional image by the line imaging unit,
The inspection control unit, when the determination unit determines that the work held in the work holding unit is not an inspection target, starts the rotation of the work by the rotation mechanism for acquiring the two-dimensional image. Inspection device to regulate.
A work holding step of holding a work having a rotationally symmetric outer peripheral portion around the axis of symmetry at the work holding position by the work holding portion;
In the work holding position, an image acquisition step of acquiring a line image by imaging a linear region extending in a radial direction from a site located on the axis of symmetry of the work held by the work holding portion,
A determination step of determining whether or not the work held by the work holding section is an inspection target based on the line image,
When the work is determined to be an inspection target by the determination step, the work held by the work holding unit is moved to the inspection position and inspected, while when it is determined not to be the inspection target, the work holding unit An inspection method which regulates movement and inspection of the held work to the inspection position.