Device for examining the surface of a component

Abstract

Device for examining a surface (9) of a component (8), in particular for examining a painted surface (9) of a body component, comprising - a light source with a light-emitting surface (7), wherein the light source is configured to generate light (6) which strikes the surface (9) of the component (8) to be examined, - a sensor unit (10) which is configured to detect a proportion (11) of the light (6) incident on the surface (9) of the component (8) emanating from the surface (9) of the component (8) to be examined, - a reflector (14) with a reflective surface (15) which is configured to reflect a portion of the light (6) emanating from the surface (9) of the component (8) to be examined onto the sensor unit (10), characterized in that the device comprises a housing (1) with a first housing part (2) and a second housing part (3), wherein the sensor unit (10) and / or the reflector (14) are arranged on or in the first housing part (2), and wherein the light emission surface (7) of the light source is arranged on or in the second housing part (3), wherein the second housing part (3) is less extended in the direction of the normal (N) on the light emission surface (7) than the first housing part (2).

Description

[0001] The present invention relates to a device for examining a surface of a component according to the preamble of claim 1, a device for examining a surface of a component according to the preamble of claim 12 and a system for examining a surface of a component according to the preamble of claim 15.

[0002] A device, a facility, and a system of the aforementioned type are known from DE 10 2018 113 919 A1. The device described therein comprises a plurality of line lasers, at least one reflector shield, and at least one camera, wherein the plurality of line lasers each cover a region of a surface of a motor vehicle to be inspected with a linear beam, wherein the linear beams of different line lasers have different colors at least in some regions with a small aperture angle, wherein each line laser is mounted on a pivoting device, and wherein the camera records an image of the region to be inspected via the reflector shield and feeds it to an evaluation unit, so that an assessment of the surface in the region to be inspected can be carried out.

[0003] Another device, another apparatus, and another system for examining a surface of a component are known from DE 10 2004 007 828 A1. The device described therein is an inspection device for a painted surface of a vehicle, which has a base layer and a clear layer applied to the base layer, the device comprising: a frame mounted on an arm of a robot; a line scan camera, wherein a first light source is provided on the line scan camera, which light source illuminates at a predetermined angle, and wherein the line scan camera is mounted on the frame and acquires first visual data by specularly reflected light from the painted surface using light from the first light source;and a controller that receives / records the first visual data from the line scan camera and detects a possible surface defect of the painted surface according to the first visual data, wherein the inspection device further comprises a second light source that vertically illuminates the painted surface so that the line scan camera acquires second visual data by diffuse reflection light from the painted surface, and wherein the controller receives / records the second visual data from the line scan camera and detects a possible interlayer defect between the base layer and the clear layer of the painted surface according to the second visual data.;

[0004] Another device, another apparatus, and another system for examining a surface of a component are known from DE 10 2004 007 828 A1. The device, the apparatus, and the system are used to examine painted surfaces of a body component. The device comprises a light source that can generate structured light, in particular light with a striped pattern. The light strikes the surface to be examined and is reflected by it. The reflected light strikes a camera, which generates corresponding image data from the detected light. The image data is evaluated by an evaluation device of the system in order to detect defects in or on the painted surface. The system further comprises a multi-axis robot that carries the device and positions it appropriately.A control device of the system controls the robot so that the device is positioned appropriately to the surface to be examined.

[0005] Painted body components can exhibit a wide variety of defects. These include, for example, raw part defects (physical damage to the raw part), inclusions (e.g., small particles that have been painted over), and a lean coating (e.g., a thin coating that corresponds to an uneven surface). These defects usually have a three-dimensional appearance on the surface. By generating a striped light that is reflected from the surface being examined, defects are easier to detect. Because a typical defect on a painted surface is usually three-dimensional, the stripes or lines of the light applied to the surface curve around the defect, making it easier to detect during analysis.

[0006] Body components whose painted surfaces must be inspected are usually held on carriers that have a plurality of superimposed receptacles for the body components. On these carriers, the individual body components are often located very close together. A disadvantage of prior art devices is that they are not capable of being inserted into the spaces between the individual body components on carriers. Therefore, these devices cannot evenly illuminate the areas located in the spaces with light. This leads to at least partially poor image quality of the generated images due to a comparatively low light output. This can lead to an increased risk of errors in the detection of defects.Furthermore, state-of-the-art devices can only expose small sections of the surface to be examined with a strip light. Furthermore, state-of-the-art devices can only capture a comparatively small section of the surface when taking an image of the surface to be examined. Both of these factors result in the need to move to many different positions, resulting in a correspondingly large number of images. This slows down the inspection of the surfaces of body components.

[0007] The problem underlying the present invention is to provide a device, a facility and a system of the type mentioned above which enable a higher process speed and / or a more reliable defect detection.

[0008] This is achieved by a device of the type mentioned at the outset having the characterizing features of claim 1, a device of the type mentioned at the outset having the characterizing features of claim 12, and a system of the type mentioned at the outset having the characterizing features of claim 15. The subclaims relate to preferred embodiments of the invention.

[0009] According to claim 1, the device comprises a housing with a first housing part and a second housing part, wherein the sensor unit and / or the reflector are arranged on or in the first housing part, and wherein the light exit surface of the light source is arranged on or in the second housing part, wherein the second housing part is less extensive in the direction of the normal to the light exit surface than the first housing part. By using a reflector, the device can be designed such that it can be introduced at least partially more easily, for example, into narrow spaces between individual body components on product carriers, thereby resulting in better accessibility in tight spaces. Furthermore, by partially introducing the device into a gap, the surface can be illuminated better and more evenly, resulting in a higher light output.Furthermore, the illuminated area of ​​the surface is increased, so that fewer images are required overall and thus faster evaluation can be achieved, which leads to a higher process speed.

[0010] It can be provided that the reflective surface forms an angle between 20° and 70° with the light exit surface, in particular an angle between 30° and 60°, preferably an angle between 40° and 50° with the light exit surface. Such an angle between the light exit surface and the reflective surface facilitates the at least partial insertion of the light exit surface into narrow spaces, for example, between individual body components on product carriers.

[0011] It is possible for the second housing part to protrude from the first housing part in a direction parallel to the light-emitting surface. In particular, this allows the second housing part with the light-emitting surface to be at least partially inserted into narrow spaces, for example, between individual body components on product carriers.

[0012] It can be provided that the first housing part and the second housing part are rigidly connected to one another. Alternatively, it is possible for the first housing part and the second housing part to be pivotably connected to one another, so that the angle between the first and second housing parts, or the angle between the reflector and the light exit surface, can be changed. In particular, the angle between the housing parts can be changed during the movement of the device.

[0013] It can be provided that the extension of the second housing part in the direction of the normal to the light exit surface is less than 20 cm, in particular less than 10 cm, preferably less than 5 cm, for example, between 1 cm and 3 cm. This greatly facilitates the insertion of the second housing part with the light exit surface into correspondingly narrow spaces between components to be examined and the illumination of these components' surfaces.

[0014] The reflector may include a mirror or consist of a mirror, with the mirror providing the reflecting surface for the portion of the light emanating from the component surface under investigation. The reflecting surface of the mirror may be flat. Alternatively, the surface may also be curved.

[0015] The sensor unit may comprise a camera with a sensor surface. A digital camera can capture images at a very high frame rate and convert the captured images into image data.

[0016] It is possible for the sensor unit to comprise a lens configured to direct, in particular focus, at least a portion of the reflected light onto the sensor surface of the camera. Due to the preferably uniform and bright illumination of the surface to be examined, an aperture provided in the lens can be partially closed. This results in a greater depth of field in the images.

[0017] It can be provided that the light source is configured to generate diffuse light at least in sections, and / or that the light source is configured to generate structured light, in particular light with a striped pattern. The preferably uniform and bright illumination of the surface to be examined and, in particular, the increased depth of field results in a robust image of the striped light reflection, so that the image of the striped light reflection hardly changes, at least with slightly different component positioning.

[0018] The camera may be designed to capture images at a frame rate of at least 10 FPS, particularly at least 25 FPS, and preferably at least 40 FPS. This allows for high processing speeds during surface inspection.

[0019] The sensor unit can, in particular, have a data interface, wherein the data interface can transmit data at a data transmission rate of at least 100 Mbit / s, in particular at a data transmission rate of at least 500 Mbit / s, preferably at a data transmission rate of at least 1 Gbit / s, for example at a data transmission rate of 5 Gbit / s. This ensures that the data generated at the high frame rate can be read from the sensor unit sufficiently quickly.

[0020] It can be provided that the device is configured to be connected to a robot and moved by the robot relative to the surface of the component to be examined, in particular wherein the device comprises connecting means for connection to the robot. In this way, the robot can position the device or the second housing part with the light exit surface appropriately for examining the surface.

[0021] According to claim 12, it is provided that the device is a device according to the invention.

[0022] The robot can be a multi-axis robot, in particular a 6-axis robot or a robot with more than six axes. Such a robot can move the device or the second housing part with the light-emitting surface into the required positions very quickly and very flexibly.

[0023] It is possible for the camera's exposure time to be between 30 µs and 100 µs, allowing the robot to move the device at a speed of at least 2 m / s without the captured images becoming blurred. Higher process speeds can also be achieved with such fast robot movements.

[0024] According to claim 15, it is provided that the device is a device according to the invention.

[0025] The evaluation device for evaluating the image data captured by the sensor unit can be configured to perform the evaluation with the aid of artificial intelligence. The artificial intelligence can have learned what a defect pattern looks like before beginning the surface inspection. During the inspection, the artificial intelligence analyzes the images and looks for defects.

[0026] It is possible that the control device and / or the evaluation device are implemented by at least one computer on which at least one computer program suitable for control and / or evaluation is installed.

[0027] Further features and advantages of embodiments of the invention are described below with reference to the drawings. The same reference numerals are used for identical or similar parts and for parts with identical or similar functions. They show: Fig. 1 a perspective view of a device according to the invention; Fig. 2 a front view of the device according to Fig. 1; Fig. 3 a section according to arrows III - III in Fig. 2; Fig. 4 a Fig. 3 corresponding view of the device with components to be examined and schematic beam paths of the light emanating from a light source of the device.

[0028] The device shown comprises a housing 1 with a first and a second housing part 2, 3. The first housing part 1 is box-shaped or cuboid-shaped, wherein the first housing part 2 is in a first direction X, which is the vertical in Fig. 2 corresponds to approximately twice as large as in the two perpendicular transverse directions (see also Fig. 3). The first direction X thus forms a longitudinal direction of the first housing part 2.

[0029] The first housing part 2 has a first or Fig. 2 lower end 4 which extends at an angle α, which in particular corresponds to approximately 135°, to the first direction X (see Fig. 3). The second housing part 3 is screwed to this first end 4 and projects away from the first housing part 2 at an angle α to the first direction X.

[0030] The second housing part 3 is vertically in Fig. 2 to Fig. 4 or in the direction of the normal N on the light exit surface 7 (see Fig. 3) significantly less extensive than the first housing part 2, wherein the extension of the second housing part in this direction is less than 20 cm, in particular less than 10 cm. Advantageously, the extension of the second housing part in this direction can be less than 5 cm, in particular between 1 cm and 3 cm, for example 2 cm. A plate 5 extends from the second housing part 3 below the first end 4 of the first housing part 2. The plate 5 is attached to this end 4, in particular by a screw connection.

[0031] The device comprises a light source arranged in the second housing part 3. The light source has at least one light-emitting diode (LED), the light 6 of which can emerge from a light exit surface 7 arranged on the underside of the second housing part 3 (see also Fig. 4). The light exit surface 7 is square in the illustrated embodiment. However, it can have a different shape, such as rectangular, circular, or oval.

[0032] The light source can be configured to generate diffuse light, at least in sections. This can be light in the visible spectral range. However, it is also entirely possible for the light source to generate infrared light instead of visible light.

[0033] The light source can be configured to generate structured light. In particular, the light source can generate light with a striped pattern. To generate light with a striped pattern, a striped light sheet can be used, which is arranged, for example, in front of the light exit surface 7. Alternatively, an LCD display, a printed film, a printed glass pane, or a printed Plexiglas pane can be used. The advantage of an LCD display is that the stripes can be switched on and off.

[0034] During operation of the device, the light 6 emanating from the light exit surface 7 strikes a surface 9 of a component 8 to be examined. The light 6 is reflected from this surface 9 (see Fig. 4).

[0035] The device further comprises a sensor unit 10 arranged in the first housing part 2. The sensor unit 10 is configured to detect a portion 11 of the light 6 incident on the surface 9 of the component 8 to be examined, which portion 11 is emitted by the surface 9 of the component 8. The sensor unit 10 generates image data based on the detected light.

[0036] The sensor unit 10 comprises a camera 12 and a lens 13. The camera 12 can, in particular, be designed to capture images at a frame rate of at least 10 FPS, in particular at least 25 FPS, preferably at least 40 FPS. The camera 12 can, for example, be a 12-megapixel monochrome camera capable of capturing images at a maximum frame rate of 63 FPS.

[0037] The lens 13 can focus the portion 11 of the light 6 at least partially onto the sensor surface of the camera 12. The lens 13 can, for example, be a 12 mm lens.

[0038] The device further comprises a reflector 14 with a reflective surface 15, which is configured to reflect a portion 11 of the light 6 emanating from the surface 9 of the component 8 to be examined onto the sensor unit 10. The reflector 14 can comprise a mirror or consist of a mirror, wherein the mirror has the reflective surface 15.

[0039] On the side facing away from the first housing part 2, a holder 16 for the reflector 14 is attached to the plate 5, in particular via the same screw connection with which the plate 5 is attached to the first housing part 2 (see Fig. 1). In the illustrated embodiment, the holder 16 of the reflector 14 is attached to the first housing part 2 such that the reflective surface 15 of the reflector 14 extends at an angle of 45° to the light exit surface 7, or such that the reflective surface 15 extends in the first direction X, which corresponds to the longitudinal direction of the first housing part 2.

[0040] The first housing part 2 has a second or Fig. 2 has an upper end 17, which is opposite the first end 4. In the area of ​​the second end 17, a flange attachment 18 is provided, serving as a connecting means for connection to a robot (not shown). The robot supports the device and can move it appropriately. The robot can be a multi-axis robot, in particular a 6-axis robot.

[0041] Due to the very flat design of the second housing part 3, which extends at an angle α from the first housing part 2, the robot can push the second housing part 3 into a narrow space 19 between two components 8 with surfaces 9 to be examined (see Fig. 4). The light 6 emitted from the light exit surface 7 of the light source is reflected by a surface 9 to be examined. A portion 11 of the reflected light strikes the reflective surface 15 of the reflector 14 and is redirected by it to the sensor unit 10. The camera 12 of the sensor unit 10 generates corresponding image data based on the captured light, which can be used to evaluate the quality of the surface.

[0042] The robot and the device are part of a system for examining the surface 9 of the component 8. In addition to the robot and the device, the system comprises a control device (not shown) for controlling the robot and an evaluation device (not shown) for evaluating the image data acquired by the sensor unit 10.

[0043] For transmitting the image data to the evaluation device, the sensor unit 10 includes a data interface (not shown). The data interface allows data to be transmitted at a data transmission rate of at least 100 Mbit / s, in particular at a data transmission rate of at least 500 Mbit / s, preferably at a data transmission rate of at least 1 Gbit / s, for example at a data transmission rate of 5 Gbit / s.

[0044] The control device and the evaluation device are implemented by at least one computer on which at least one computer program suitable for control and / or evaluation is installed. For example, a computer program suitable for both control and evaluation can be installed. Alternatively, a computer program suitable for control and a computer program suitable for evaluation can also be installed.

[0045] The control device controls the robot so that the device is positioned appropriately relative to the surface to be examined. The control device can also be configured to control the camera via the robot so that it captures images.

[0046] The evaluation device is designed to carry out the evaluation with the aid of artificial intelligence.

Claims

[1] Device for examining a surface (9) of a component (8), in particular for examining a painted surface (9) of a body component, comprising - a light source with a light exit surface (7), wherein the light source is designed to generate light (6) which impinges on the surface (9) of the component (8) to be examined, - a sensor unit (10) which is designed to detect a portion (11) of the light (6) incident on the surface (9) of the component (8) to be examined, - a reflector (14) with a reflective surface (15) which is designed to reflect a portion of the light (6) emanating from the surface (9) of the component (8) to be examined onto the sensor unit (10), characterized bythat the device comprises a housing (1) with a first housing part (2) and a second housing part (3), wherein the sensor unit (10) and / or the reflector (14) are arranged on or in the first housing part (2), and wherein the light exit surface (7) of the light source is arranged on or in the second housing part (3), wherein the second housing part (3) is less extensive in the direction of the normal (N) on the light exit surface (7) than the first housing part (2). [2] Device according to claim 1, characterized by that the reflecting surface (15) encloses an angle between 20° and 70° with the light exit surface (7). [3] Device according to one of claims 1 or 2, characterized by that the second housing part (3) projects away from the first housing part (2) in a direction parallel to the light exit surface (7). [4] Device according to one of claims 1 to 3, characterized bythat the extension of the second housing part (3) in the direction of the normal (N) on the light exit surface (7) is less than 20 cm. [5] Device according to one of claims 1 to 4, characterized by that the reflector (14) comprises or consists of a mirror, wherein the mirror has the reflecting surface (15) for the portion (11) of the light (6) emanating from the surface (9) of the component (8) to be examined. [6] Device according to one of claims 1 to 5, characterized by that the sensor unit (10) comprises a camera (12) with a sensor surface. [7] Device according to claim 6, characterized by that the sensor unit (10) comprises a lens (13) which is designed to direct, in particular to focus, at least a portion of the reflected light onto the sensor surface of the camera (12). [8] Device according to one of claims 1 to 7, characterized bythat the light source is designed to generate diffuse light (6) at least in sections, and / or that the light source is designed to generate structured light (6). [9] Device according to one of claims 6 to 8, characterized by that the camera (12) is designed to capture images at a frame rate of at least 10 FPS. [10] Device according to one of claims 1 to 9, characterized by that the sensor unit (10) has a data interface, wherein the data interface can transmit data at a data transmission rate of at least 100 Mbit / s. [11] Device according to one of claims 1 to 10, characterized by that the device is designed to be connected to a robot and to be moved by the robot relative to the surface (9) of the component (8) to be examined. [12] Device for examining a surface (9) of a component (8), in particular for examining a painted surface (9) of a body component, comprising - a device for examining a surface (9) of a component (8), in particular for examining a painted surface (9) of a body component, - a robot which is connected or connectable to the device and is designed to move the device relative to the surface (9) of the component (8) to be examined, characterized by that the device is a device according to one of claims 1 to 11. [13] Device according to claim 12, characterized by that the robot is a multi-axis robot. [14] Device according to one of claims 12 or 13, characterized bythat the exposure time with which the camera (12) takes pictures is between 30 µs and 100 µs, so that the robot can move the device at a speed of at least up to 2 m / s without the taken pictures becoming blurred. [15] System for examining a surface (9) of a component (8), comprising - a device for examining a surface (9) of a component (8), - a control device for controlling the robot, - an evaluation device for evaluating the image data acquired by the sensor unit (10), characterized by that the device is a device according to one of claims 12 to 14. [16] System according to claim 15, characterized by that the evaluation device for evaluating the image data acquired by the sensor unit (10) is designed to carry out the evaluation with the aid of artificial intelligence. [17] System according to one of claims 15 or 16, characterized by that the control device and / or the evaluation device are implemented by at least one computer on which at least one computer program suitable for control and / or evaluation is installed.

Images