TESTING DEVICE FOR OPTICAL INSPECTION OF AN OBJECT, PRODUCTION PLANT WITH THE TESTING DEVICE AND METHOD FOR OPTICAL INSPECTION OF THE OBJECT WITH THE TESTING DEVICE

Description

State of the art

[0001] The invention relates to a testing device for optically testing an object, comprising a camera device, wherein the camera device has a focal plane with a recording area and is designed to record an image of the recording area, comprising a handling device for gripping and / or recording the object, comprising a control device for controlling the handling device, wherein the control device is designed to control the handling device for positioning the object in the recording area.

[0002] Special-purpose machines are typically used in production to automate visual inspection tasks. The product range to be inspected, including all inspection positions, must be known during system development. For this purpose, fixed camera positions are defined for each product-specific inspection task. During commissioning, the image width and / or focal length are manually adjusted so that the image quality meets the requirements of the inspection task and then mechanically fixed. Later adjustments are sometimes possible, but this is very complex and expensive.

[0003] The document DE 44 26 968 C2 discloses an optical inspection device with at least one light source, a light guide, and a light-receiving inspection system, wherein the at least one light source feeds light into the light guide. The optical inspection device has an opening delimited on an inner side by four walls, in which an object to be examined is received and has reflectors on its outer edge and further reflectors inclined at different angles to the walls. The reflectors redirect a portion of the fed-in light such that the side surfaces of the object are illuminated, the further reflectors redirect a further portion of the fed-in light such that the top side of the object is illuminated, and the walls redirect the light reflected from the side surfaces of the object toward the inspection system, which faces the top side of the object.

[0004] EP 2 684 651 A2 discloses a robot system with a motion unit, for example, a robot arm, and a camera. The motion unit is movable within a workspace. A storage unit contains a shape model of the motion unit. The orientation and position of the motion unit are determined based on a matching process between the camera images and the shape model.

[0005] Publication WO 03 / 039820 A1 describes a method for determining the position and orientation of an object in three-dimensional space. A camera captures images of the object, which are then evaluated and compared with a model.

[0006] EP 2 639 766 A1 discloses a device for creating a model of an object under examination. The model is created based on images of the object under examination.

[0007] Document DE 10 2012 014 451 A1, which represents the closest prior art, describes a method for controlling a robot. A sensor unit is located on one of the robot's arms. The robot arm is controlled in such a way that a linear area of ​​a test object is inspected based on sensor data and a model. Disclosure of the invention

[0008] Within the scope of the invention, a testing device for optically testing an object with the features of claim 1 is proposed. Furthermore, a production system with the features of claim 11 and a method for optically testing the object with the testing device with the features of claim 12 are proposed. Preferred and / or advantageous embodiments of the invention emerge from the subclaims, the following description, and the accompanying figures.

[0009] According to the invention, a testing device for optically inspecting an object is proposed. The testing device is a stationary or mobile testing device. In particular, the testing device is designed for integration into a production system, a manual workstation, or as a standalone system. It is particularly preferred that the testing device be a pick-and-place testing device.

[0010] Optical testing corresponds in particular to a visual inspection of the object, for example in the visible wavelength range, the infrared wavelength range, or the ultraviolet wavelength range of light. The object is, for example, a component, a workpiece, and / or a product of a production plant. The object, as a whole or in sections, has a shiny, reflective, matte, or absorbent surface. The object can have different sizes, for example, be smaller than ten centimeters or larger than one hundred centimeters. The testing device is particularly designed to optically inspect a different portfolio of objects, in particular to optically inspect different objects.

[0011] The testing device has a camera device. Preferably, the camera device comprises one camera or a plurality of cameras, such as at least two cameras and in particular at least ten cameras. In particular, the camera device has a transmitted-light camera. The camera device and / or the cameras have a recording direction. The camera device has at least one plane of focus; for a large number of cameras included in the camera device, the camera device can have a plurality of planes of focus. The plane of focus can also be designed as a field of focus. The plane of focus comprises a recording region, wherein, if there are multiple planes of focus, the camera device can comprise a plurality of recording regions. The recording direction is in particular perpendicular to the recording plane.The recording plane is in particular the area that is completely and sharply depicted in the image by the camera device.

[0012] The camera device is designed to capture at least one image of the recording area. The camera is, in particular, a video camera; alternatively, the camera is a single-image camera. In particular, the camera is a CCD camera, for example, a color camera or a black-and-white camera. Alternatively, the camera is a CMOS camera. The camera can also be an infrared camera or an ultraviolet camera.

[0013] The testing device comprises a handling device for gripping and / or picking up the object. In particular, the handling device is designed to move the object, for example, to move the object along a path and / or a trajectory. The handling device is, for example, a robot, in particular a robot arm. The handling device is preferably a three-axis, a six-axis, or a multi-axis robot. The handling device has, for example, a gripper, wherein the gripper is designed to grip and hold the object. The handling device can hold the object, for example, pneumatically, mechanically, or by means of an electromagnetic force. The handling device holds and / or picks up the object, in particular, in a force-fitting, positive-fitting, or friction-fitting manner.

[0014] The testing device has a control device for controlling the handling device. The control device is embodied, for example, as a computer unit, a processor unit, or a microchip. For example, the control device controls the handling device using control signals, wherein the control device is connected to the handling device via data and / or signaling. It is particularly preferred that the control device is part of the handling device and / or is included in it.

[0015] The control device is designed to control the handling device for positioning the object in the receiving area. For example, the control device controls the handling device with control signals, wherein the handling device moves the object into the receiving area and / or positions the object in the receiving area based on the control signals. In particular, the positioning of the object in the receiving area is the positioning of the surface of the object in the receiving area.

[0016] The control device comprises a model of the object. In particular, the model of the object can be stored in the control device, for example, in data format. The model of the object is preferably a 3D model; in particular, the model of the object is a CAD model.

[0017] The control device is configured to control the handling device to position the object in the recording area based on the model of the object. The control device can control the handling device to move the object according to a trajectory to the recording area based on the model. In particular, the control device uses the model to calculate and / or determine the trajectory and / or path along which the handling device must move the object into the recording area.

[0018] The invention is based on the idea of ​​providing a test device that is adaptable to different objects, whereby the optics and / or handling device do not need to be adjusted when changing the objects to be tested. In particular, the invention enables a adaptable test device for testing an object without having to make a hardware change when the object portfolio to be tested changes. In particular, the test device represents a cost-effective solution to the disadvantages of the prior art.

[0019] In a particularly preferred embodiment of the invention, the control device is designed to control the handling device for positioning the object in the focal plane based on the model. In particular, the handling device positions the object in the focal plane of the camera device based on the control signals. In particular, the positioning of the object in the focal plane is the positioning of the object's surface in the focal plane. Specifically, the recording area is understood to be an area that lies entirely within the focal plane.

[0020] One possible embodiment of the invention provides that a section of the model, in particular any section of the model, can be selected as a selection area. For this purpose, the testing device comprises, for example, an input device and / or input means, wherein a user can select the section of the model as a selection area using the input device. Specifically, multiple sections of the model can be selected as selection areas. Preferably, the section of the model can be selected graphically in the model, for example, on a display device included in the input device.

[0021] The control device is designed to determine a section of the object corresponding to the selection area as the object selection area. The object selection area corresponds in particular to the area on the object that is correspondingly selected on the model as the selection area. The control device is designed to control the handling device for positioning the object with the object selection area in the recording area and / or the focal plane. In particular, the control device is designed to control the handling device such that the object with the object selection area is moved into the recording area and / or the focal plane and / or is positioned there. When selecting several selection areas, the control device is designed, for example, to position corresponding object selection areas one after the other in the recording area and / or the focal plane of the camera device.This design is based on the idea of ​​providing a testing device that allows a selective and specific testing of the object with a testing device.

[0022] In one possible embodiment of the invention, the control device comprises device data. The device data includes, in particular, information on the geometry, structure, distances, and / or possible movements and / or trajectories of the handling device. For example, the device data includes all possible paths that the handling device can travel and / or on which the handling device can move the object.

[0023] The control device is configured to control the handling device based on the device data for collision-free positioning of the object in the recording area and / or the focal plane. Collision-free means, in particular, without collision between the object, the camera device, and / or the handling unit. In particular, the control device is configured to use the device data to determine a path and / or trajectory along which the object can be positioned in the recording area and / or the focal plane and / or moved into the recording area and / or the focal plane without collision and / or crash. This configuration is based on the idea of ​​providing a testing device that enables safe handling of the object during testing.

[0024] It is particularly preferred for the testing device to comprise a lighting device. The lighting device, in particular, has a plurality of light sources. In particular, the lighting device has more than ten, in particular more than fifteen, and especially more than one hundred light sources. The light sources are, for example, LEDs. In particular, the light sources are white light sources, infrared sources, colored light sources, and especially RGB light sources. The light sources are, in particular, point light sources; alternatively and / or additionally, the light sources are planar light sources, such as OLED surfaces.

[0025] The control device is designed to control the illumination unit in order to be able to record a high-contrast image of the recording area and / or the plane of focus, in particular in order to record a high-contrast image of the object positioned in the recording area and / or in the plane of focus with the camera device. The control device is designed, for example, to control the light sources of the illumination unit individually and / or in groups, for example, to switch an LED and / or a group of LEDs on or off, so that the desired illumination of the recording area and / or the plane of focus is achieved. This embodiment is based on the idea of ​​providing an inspection device that records high-quality and analyzable images of the object. In particular, this embodiment enables consistent image quality.

[0026] One possible embodiment provides for the control device to include at least one selectable test program. The test program contains, for example, information about the type of image to be captured, such as an infrared image, a visual image, or a black-and-white image. In particular, the test program includes the selected area of ​​the object to be examined. Specifically, the test program also includes information about the illumination provided by the lighting unit.

[0027] The control device is particularly designed to control the handling device based on the selected test program for positioning the object in the recording area and / or the focal plane. In particular, the control device is designed to capture the object selection area of ​​the object as an image based on the test program, which corresponds to the selection area of ​​the selection area stored in the test program. Specifically, the test program can be selected, adapted, and / or set using the input device. This embodiment is based on the idea of ​​providing a testing device that can be particularly easily adjusted by a user to the test to be performed.

[0028] It is particularly preferred that the control device is configured to control the illumination unit in order to capture an image of the object positioned in the recording area and / or in the focal plane in accordance with the inspection program. In particular, the control device is configured to illuminate the object by controlling the illumination unit in such a way that an image can be captured in accordance with the inspection program.

[0029] One embodiment provides that the testing device has a rest detector. The rest detector is preferably arranged on the gripper and / or on the handling device. The rest detector is in particular a vibration detector and / or an acceleration sensor. The rest detector is designed to detect when the handling device and / or the gripper is at rest and / or when the handling device and / or the gripper is free of vibration. The camera device is designed to only record an image when the rest detector has detected that the handling device is at rest and / or free of vibration. This embodiment is based on the idea of ​​providing a testing device that excludes the recording of unevaluable and / or blurry images of the object.

[0030] In a particularly preferred embodiment of the invention, the camera device is a camera device with a fixed focal length and / or a fixed image distance. In particular, the camera device comprises cameras with a fixed focal length and / or a fixed image distance. The focal length and / or the image distance of the camera device is therefore, in particular, not adjustable. In particular, the camera device is a non-focusable camera device. This embodiment is based on the idea of ​​providing a particularly inexpensive testing device without having to use expensive focusing lenses for the camera devices.

[0031] A particularly preferred embodiment of the invention provides that the testing device comprises a start position determination module. The sharpness of the image is used, in particular, as an optimization parameter for determining the start position. For example, it is also possible for the start position determination module to be part of the control device. The start position determination module is designed to determine a start position of the object gripped and / or held by the handling device. In particular, the start position determination module is designed to determine the start position for a fixed focal length and image length. In particular, the start position comprises the position and / or orientation of the object gripped by the holding device, in particular at an initial point in time.This embodiment is based on the consideration of providing a testing device which enables referencing of a starting position of the object, in particular so that the path and / or trajectory for positioning the object in the recording area can be correctly determined and / or executed.

[0032] In this case, it can be provided that the control device is configured to control the handling device so that the object is moved from the starting position into the receiving area and / or positioned in the receiving area. In particular, the control device is configured to control the handling device such that the object is moved from the starting position into the receiving area without crashes and / or collisions. Preferably, the control device is configured to optimize the path with regard to short cycle times.

[0033] It is particularly preferred that the start position determination module is designed to control the camera device to record at least one estimated image, in particular at least two estimated images, and especially at least three estimated images. Preferably, fewer than ten estimated images and especially fewer than five estimated images are recorded. Particularly preferred is the recording of three estimated images. The estimated image is preferably a live image of the object recorded by the camera device. In particular, the estimated images are images of image sections of the object, wherein these image sections are not far apart. Preferably, the different image sections of the object can be recorded by the camera device as an estimated image without moving and / or with slight movement of the handling device. For example, the image sections overlap at least in pairs.

[0034] The start position determination module is designed to compare the model with the at least one estimated image, for example to compare it with the CAD model. In particular, the start position determination module is designed to compare the model with a plurality of estimated images of the object. The start position determination module is further designed to determine the start position of the object by comparing the model with the at least one estimated image, in particular to determine the orientation, position and / or arrangement of the object in the start position. The determination of the start position by the start position determination module is to be understood in particular as an initialization of the testing device. This embodiment is based on the idea of ​​providing a testing device which determines the start point of a position of the object to be measured in a particularly simple manner.Furthermore, it is a consideration of the invention to determine the starting position without completely scanning the object, whereby in particular the time for determining the starting position can be reduced, since it is not necessary to wait for the mechanical settling times when moving the object.

[0035] A further subject matter of the invention is a production plant with the inspection device. The production plant is, in particular, a workstation, a robot workstation, a machine workstation, or a manual workstation for a person for producing the object. The inspection device is preferably designed to automatically and / or independently grasp and / or pick up an object produced by the production plant. In particular, the inspection device is designed to optically inspect at least 90 percent of the produced parts. Specifically, the inspection device is designed to optically inspect all, i.e., in particular, 100 percent, of the objects produced by the production plant.This design is based on the idea of ​​providing a production plant, in particular a production plant with a changing product portfolio, with a testing device which enables a particularly simple and inexpensive optical inspection of the produced objects.

[0036] A further subject of the invention is a method for optically inspecting the object using the inspection device. The method is characterized in particular by the control device controlling the handling device. In particular, the control device controls the handling device such that the object is positioned in the recording area of ​​the camera device based on the model. In particular, the object is positioned by the handling device in the recording area and / or in the focal plane. This subject of the invention is based on the idea of ​​providing a simple and cost-effective method for optically inspecting an object.

[0037] A particularly preferred embodiment of the method provides for the handling device to pick up the object. For example, the handling device picks up the object directly from the production system. The handling device is, for example, a pick-and-place device. In this embodiment, the camera device records at least one estimated image of the object, and the starting position determination module compares this estimated image with the model of the object and determines the object's starting position based on this comparison.

[0038] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. It shows: Figure 1 an embodiment of the test device.

[0039] Figure 1shows an embodiment of the testing device 1. The testing device 1 comprises a handling device 2 and a camera device 3. The handling device 2 is designed to handle and grip an object O.

[0040] The handling device 2 comprises a base 4 and a multi-axis robot 5 mounted and / or arranged thereon. In particular, the base 4 is for vibration-free and / or stable mounting of the multi-axis robot 5. At its free end, the multi-axis robot 5 comprises a gripper 6. The gripper 6 is designed to grip and hold, in particular to hold the object O in a force-fitting, form-fitting and / or friction-fitting manner. The gripper 6 is movable in a working area of ​​the handling device 2, wherein the gripper 6 is movable on a definable path within the working area.

[0041] The object O is, in particular, a component. The component is preferably an electronic component, an automotive supplier part, or a production product. The object O is preferably smaller than ten centimeters and, in particular, smaller than five centimeters. Alternatively, the object O can be a larger-format object, for example, a fender, with such an object preferably having a length greater than half a meter and, in particular, greater than one millimeter. The object O can be a flat object; alternatively, the object O is a voluminous object.

[0042] An object O gripped by the gripper is movable in particular in the working area of ​​the handling device 2, wherein the object O describes the same path as the gripper 6 of the handling device 2.

[0043] For orientation, a coordinate system K is shown, wherein the coordinate system K defines an X-direction, a Y-direction, and a Z-direction. The path traversed by the gripper 6 and / or the object O in the working area of ​​the handling device 2 can be described in particular by the X-direction, Y-direction, and Z-direction.

[0044] The testing device 1 comprises the camera device 3, which has a housing 7, a camera 8, and an illumination unit 9. The camera 8 is, for example, a CCD camera; alternatively, the camera 8 is a CMOS camera.

[0045] The housing 7 is designed as a dome-shaped hollow body, in this exemplary embodiment as a hemispherical hollow body. The hemispherical hollow body is cut open, in particular, in the equatorial plane. The housing 7 has an opening, wherein a focal plane 10 of the camera 8 and / or the camera device 3 is arranged in the opening. The housing 7 has an interior region, wherein the interior region is preferably reflective; alternatively, the interior region is absorbent.

[0046] The illumination unit 9 is arranged in the interior of the housing 7, wherein the illumination unit 9 comprises a plurality of light sources, in particular LEDs. The LEDs are arranged, in particular, equidistantly and / or uniformly on the interior of the housing 7. Opposite the focal plane 10 is another opening, which is arranged at the pole of the hemispherical housing 7. The camera 8 is arranged in this opening at the pole, facing the focal plane 10.

[0047] The focal plane 10 has a recording area 11. The recording area 11 is, in particular, the area that is imaged completely, in particular with high contrast, by the camera 8. The recording area 11 is, in particular, an area with a surface area greater than one square centimeter, and more specifically, greater than ten square centimeters. The recording area 11 is a flat area, in particular a planar area. Alternatively, the recording area 11 is a curved area, in which case the focal plane 10 is also a curved plane.

[0048] The handling device 2 is connected to the control device 13 via a data connection 12. The data connection 12 can be a wired connection; alternatively, the connection 12 is a virtual connection, for example, a wireless connection in the form of an infrared connection.

[0049] The control device 13 is embodied, for example, as a computer unit. The control unit 13 preferably comprises a display unit 14. The display unit 14 is, in particular, a touchscreen monitor. The control device 13 comprises a model 15 of the object O. The model 15 is, in particular, a 3D model, for example, a CAD model. The model 15 is, in particular, a true-to-scale model. The model 15 preferably comprises the position, orientation, position, and / or geometric information of the camera device 3. It is particularly preferred that the model 15 comprises the position of the focal plane 10 and, in particular, of the recording area 11.

[0050] The control device 13 has input means 16, wherein the input means 16 are, for example, a computer mouse; alternatively, the input means 16 can also be designed as a touchscreen monitor. By means of the input means 16, a user can select a selection area 17 in the model 15 of the object O. In particular, the selection area 17 can be freely selected in the model 15. The selection area 17 is, in particular, a flat area which can be delimited by a straight line and / or a curvature. In addition, the selection area 17 of the model 3 corresponds in the real world on the object O to an object selection area 18. The object selection area 18 is the area on the real object that was selected on the model 15 as the selection area 17.The control device 13 is configured to determine a trajectory 19 along which the object O must be moved with the object selection area 18 so that the object selection area 18 lies in the recording area 11 and / or the focal plane of the camera device 3. This trajectory 19 can be parameterized and / or calculated, in particular, using the coordinate system K.

[0051] The handling device 2 is controlled by the control device 13 such that the object O is moved along the trajectory 19 with the object selection area 18, and after the movement, the object selection area 18 is located in the recording area 11. By moving the object O with the object selection area 18 into the recording area 11 and / or into the focal plane, a particularly cost-effective inspection device 1 can be achieved, since cameras 8 with a constant focal length and without expensive focusing devices can be used.

Claims

1. Inspection apparatus (1) for optically inspecting an object (O), comprising a camera device, the camera device (3) having a focal plane (10) with recording region (11) and being configured to record an image of the recording region (11), comprising a handling device (2) for gripping and / or picking up the object (O), comprising a control device (13) for controlling the handling device (2), the control device (13) being configured to control the handling device (2) for positioning the object (O) in the recording region (11), the control device (13) comprising a model (15) of the object (O), the model (15) of the object (O) being configured as a 3D model, the control device (13) being configured to control the handling device (2) for positioning the object (O) in the recording region (11) on the basis of the model (15), characterized in that the handling device (2) has a rest detector, the rest detector being configured to detect when the handling device (2) is at rest and / or is free of vibration, the camera device (3) being configured to record the image only if the handling device (2) is at rest and / or is free of vibration.

2. Inspection apparatus (1) according to Claim 1, characterized in that a section of the model (15) is selectable as a selection region (17), the control device (13) being configured to determine a section of the object (O) that corresponds to the selection region (17) as an object selection region (18), and to control the handling device (2) for positioning the object (O) with the object selection region (18) in the recording region (11).

3. Inspection apparatus (1) according to any of the preceding claims, characterized in that the control device (13) is configured to control the handling device (2) on the basis of the apparatus data for collision-free positioning of the object (O) in the recording region (11).

4. Inspection apparatus (1) according to any of the preceding claims, characterized by an illumination device (9), the control device (13) being configured to control the illumination unit (9) in order to record a high-contrast image of the object (O) positioned in the recording region (11) by way of the camera device.

5. Inspection apparatus (1) according to any of the preceding claims, characterized in that the control device (13) comprises at least one selectable inspection program, the control device (13) being configured to control the handling device (2) on the basis of the selected inspection program for positioning of the object (O) in the recording region (11).

6. Inspection apparatus (1) according to Claim 5, characterized in that the control device (13) is configured to control the illumination unit (9) in order to record an image of the object (O) positioned in the recording region (11) in accordance with the inspection program.

7. Inspection apparatus (1) according to any of the preceding claims, characterized in that the camera device is a camera device having a fixed focal length and / or having a fixed image distance.

8. Inspection apparatus (1) according to any of the preceding claims, characterized by a starting position determining module, the starting position determining module being configured to determine a starting position of the object (O) gripped and / or held by the handling device (2).

9. Inspection apparatus (1) according to Claim 8, characterized in that the control device (13) is configured to control the handling device (2) so that the object (O) moves from the starting position into the recording region (11) and / or is positioned in the recording region (11).

10. Inspection apparatus (1) according to Claim 8 or 9, characterized in that the starting position determining module is configured to control the camera device for recording at least one estimated image, and to compare the model (15) with the at least one estimated image, and to determine the starting position of the object (O) by way of the comparison.

11. Production facility comprising the inspection apparatus (1) according to any of the preceding claims for the production of the object (O), the inspection apparatus (1) being configured to optically inspect at least 90 per cent of the produced objects (O).

12. Method for optically inspecting the object using the inspection apparatus (1) according to any of the preceding claims, characterized in that the control device (13) controls the handling device (2) to position the object in the recording region (11) of the camera device on the basis of the model (15).

13. Method for optical inspection according to Claim 12, characterized in that the handling device (2) picks up and / or grips the object, the camera device records at least one estimated image of the object, the starting position determining module comparing the estimated image with the model (15) and determining the starting position on the basis of the comparison.