DE102018107726B4 - Tool for machining a workpiece and recording machining points - Google Patents

Abstract

Tool (1) for machining a workpiece and for detecting machining points, the tool (1) having a time-of-flight camera (2) with a transmitter (5) that emits light, an optical sensor (6) operating according to the time-of-flight method and control electronics (7) , which controls the transmitter (5) and the optical sensor (6), the sensor (6) being constructed as a pixel array, characterized in that the tool (1) has a release device (11) which enables processing with the Tool (1) only releases when the processing point has been recognized and a storage entry has been created for documentation.

Description

The present invention relates to a tool for machining a workpiece and for detecting machining locations, a method for machining a workpiece and for detecting machining locations, and the use of a tool with a time-of-flight camera.

In automated series production, the assembly processes of machines are carried out automatically. These assembly processes include in particular the tightening or loosening of screws or nuts, or riveting processes. The machines can carry out the work steps quickly, precisely and carefully with the help of conventional sensors, for example by using laser path measuring systems.

The writings show generic hand tools: EP 3 162 479 A1 , EP 1 275 470 A2 , WO 2007/ 042 569 A1 , DE 100 37 019 A1 , DE 103 40 426 B4 , EP 1 908 542 A1 , DE 43 36 730 A1 , US 6,536,536 B1 , US 9,114,493 B2 , US 2002 / 0 162 978 A1 , DE 10 2006 005 410 A1 , DE 10 2009 007 977 A1 , DE 10 2015 215 406 A1 . Hand tools with a TOF camera as a sensor show the writings US 2012 / 0 006 877 A1 and DE 10 2017 203 149 A1 .

However, there are work processes that cannot be carried out using machines or can only be carried out purely mechanically with disproportionate effort. Such operations are still carried out by hand. As a rule, hand-held tools, such as hand-held electric screwdrivers, are used for this purpose. These electric tools are used either corded or cordless, i.e. battery operated.

However, these machining processes, which are carried out manually with the help of tools, cause problems in connection with process reliability. In order to guarantee and prove product safety, it is necessary to manufacture the products according to the current state of the art and to document the assembly process in a comprehensible and detailed manner. Correct processing can only be documented with fully monitored processing processes and a clear distinction between each processing process. This applies especially to safety-relevant screw connections, such as category A screwing cases according to VDIA/DE 2862, which pose a danger to life, limb and the environment in the event of failure, for example due to incomplete or improper screw connection. In order to distinguish and document the individual machining processes in as much detail as possible, attempts are made to record the positioning of the tools, especially the hand-held tools, as precisely as possible throughout.

For this purpose, the tools are brought to the processing points via manipulators with measurement recording devices, or real-time positioning systems are used that can locate the tools in space. Localization is carried out using radio transmitters attached to the tools, using cameras positioned in the room that record the tool and the workpiece, or, in the case of wired tools, using a camera attached directly to the tool that records the processing points.

However, localization using radio transmitters or cameras arranged in space requires a complex network of sensors/receivers/cameras and is associated with high costs.

The disadvantage of the tools known from the prior art, which have a camera for recording the processing point, is that the images recorded are often unusable. This is due, among other things, to the fact that ambient light, changing material surfaces and material colors as well as perspective distortions affect the recordings. In addition, reference images that show the workpiece against a background can no longer be used if the background has changed, for example due to changed lighting conditions. The lenses used in these industrial cameras are heavy and have an extremely negative impact on the handling of the tools. In addition, powerful data processing systems are necessary for evaluating the recordings, as the evaluation is computationally intensive, so such data processing systems cannot be attached to wireless, i.e. battery-operated, tools due to the high energy requirement. In the event that data processing takes place externally, high latency times are recorded or additional data and power lines are necessary, which limit the manageability of the tools.

The object of the invention is to provide a tool that overcomes the disadvantages known from the prior art. The object of the invention can therefore be seen as providing a tool that can clearly detect the processing locations regardless of the ambient light, the material surface and color, and the perspective, without significantly restricting the handling of the tool.

To solve the problem, a tool is provided for machining a workpiece and for detecting machining points, which is characterized in that the tool has a time-of-flight camera with a transmitter that emits light, an optical sensor that works according to the time-of-flight method and control electronics that control the Transmitter and the optical sensor.

The aim of the workpiece detection systems according to the state of the art is to capture the workpiece with as high a resolution as possible and therefore in detail. However, since the sensors used in time-of-flight cameras have a much lower pixel density, sometimes less than 200 x 200 pixels, it was particularly surprising that a tool with a time-of-flight camera for workpiece detection is advantageous over the conventional tools used in the prior art high-resolution cameras.

The time-of-flight camera can be integrated into the tool or placed on the outside of the tool. The individual components of the time-of-flight camera can be arranged at different locations. Components can be partially integrated into the tool and partially placed on the tool from the outside. It is clear that the transmitter is arranged so that the emitted light can hit the workpiece and the sensor is arranged so that it can detect the light reflected back from the workpiece.

The time-of-flight camera is a camera that determines distances using the time-of-flight method, for which light is emitted onto an area of the workpiece via a transmitter, i.e. an emitter, and the distance is determined based on the time that the light takes from the transmitter to the workpiece and the sensor is calculated for each pixel. The light is emitted either as a light pulse or modulated with a sinusoidally changing intensity.

The time-of-flight camera comprises a transmitter, preferably in the form of LEDs or laser diodes, which preferably emits light with wavelengths of >700 nm, particularly preferably >750 nm, in particular >800 nm, in order to ensure as little disruption to the environment as possible. This also ensures that the time-of-flight camera is less sensitive to natural environmental influences.

Another component of the time-of-flight camera is a sensor, i.e. detector, which is constructed as a pixel array and measures the time of flight for each pixel. A PMD sensor (photomix detector) is preferably used as the sensor. The PMD sensor can preferably actively suppress extraneous light.

The time-of-flight camera also includes control electronics that control the transmitter and the optical sensor.

The time-of-flight camera can further comprise one or more of the components selected from the group consisting of a light filter, lens, data storage, interface and output unit, such as a screen or loudspeaker.

The tool preferably has optics that collect the light reflected from the environment and direct it to the sensor.

The tool preferably has a handle and a tool head. The tool head includes the area that is brought into contact with the workpiece for processing or with the element to be attached to the tool, i.e. the holding device. In the case of a screwdriver, for example, this would be the screwdriver holder for a screwdriver socket or a bit. The time-of-flight camera, at least the transmitter and the sensor, are preferably arranged in the area of the tool head. The transmitter and the sensor of the time-of-flight camera are preferably arranged on the tool head in such a way that they are directed towards the machining point during the machining process.

The distance to the workpiece calculated by the time-of-flight camera is preferably output as a coordinate (X, Y, Z) per pixel by the time-of-flight camera, so that the output data provides information via a type of “point cloud”. Since only one distance is stored per pixel, the amount of data per shot is very small compared to a conventional photo shot. This has the advantage that the data can be transferred and processed quickly and takes up little storage space. It is therefore advantageous that the workpiece can be captured three-dimensionally without large amounts of data being generated per recording.

The tool is preferably a hand-held electric tool, preferably a hand-held EC tool, particularly preferably a hand-held EC screwdriver.

In an advantageous embodiment, the tool according to the invention is operated wirelessly. According to the invention, “wireless” means that no external power source supplies the energy using a cable, but rather a battery, an accumulator or a capacitor is integrated into the tool for the energy supply is. Cordlessly operated tools can be handled flexibly, can be carried along without the need for an additional storage option for the tool near the processing point, and, in the case of a sensitive workpiece, such as a painted one, cause less damage due to the elimination of the cable. Until now, tools with an integrated camera could only be operated using a cable, as the conventional cameras and data processing devices used required such high performance that battery operation was not possible for a sufficiently long time. The power consumption of the tools according to the invention, on the other hand, is sufficiently low so that long working times are possible.

In an advantageous embodiment of the invention, the tool has a data processing device and/or can access an externally arranged data processing device which processes the data output by the time-of-flight camera. The data processing device is preferably integrated in the tool according to the invention, so that the tool does not have to access any external data processing device.

It is advantageous if the tool has a data memory and/or can access an external data memory in which the data output by the data processing device and/or by the time-of-flight camera are stored, preferably together with time information. The time information contains information about at least one time, preferably selected from the output time of the data output by the time-of-flight camera, the time of the photo camera recording or the storage time, whereby it should be noted that these times usually only differ minimally from one another. The time information therefore preferably contains information about the date and time, which is preferably determined at least to the second. The data storage is preferably integrated in the tool according to the invention, so that no external data storage is necessary. The time-of-flight camera is preferably set so that continuously and at a short time interval, preferably at a time interval of less than 5 seconds, particularly preferably of less than 1 second, very particularly preferably of less than 0.5 seconds, before the processing process, at least one recording is made during the editing process and/or after the editing process, the data and/or the corresponding time information being stored in the data memory for documentation.

In an advantageous embodiment, the data processing device compares the data output by the time-of-flight camera with stored data from predetermined processing points and, if there is a match, assigns the data output by the time-of-flight camera to the corresponding predetermined processing point and creates a memory entry. The specified machining points are the points on the workpiece where the tool is to be placed for machining. The data of these predetermined processing points were created in advance and stored in the data memory, preferably in the data memory integrated in the tool, to serve as a reference. By comparing the stored data of the reference points with the data output by the time-of-flight camera with the specified processing points, it can be determined whether the recorded area of the workpiece corresponds to one of the specified processing points, which is the case if there is a match. The data output by the time-of-flight camera can first have been processed by the data processing device before the comparison and can only be compared with the reference data in processed form. The type of reference data preferably corresponds to the data output by the time-of-flight camera, so that the reference data is also preferably available as a “point cloud”, i.e. as a 3D image.

The data are preferably compared using logic, with fuzzy logic preferably being used. Agreement does not necessarily mean 100% agreement, so that deviations due to recording inaccuracies can be tolerated.

In an advantageous embodiment, the comparison process, in which the data processing device compares the data output and possibly processed by the time-of-flight camera with reference data, is continuously optimized using machine learning methods.

In an advantageous embodiment, the memory entry contains at least information about the recognized, assigned processing point, preferably together with time information. The time information contains information about at least one time, preferably selected from the output time of the data output by the time-of-flight camera, the time of the photo camera recording or the storage time. The time information therefore preferably contains information about the date and time, which is preferably determined at least to the second. This ensures complete documentation of the processing of the workpiece. It is also planned that data from the already stored prepared workpiece areas are used as a reference with which the data output by the time-of-flight camera is compared. If the data output by the time-of-flight camera of a processing point that has already been processed match the stored data of the corresponding processed processing point specified as a reference, it can be documented in this way that the processing was carried out correctly. In this way, for example, it can be monitored and/or documented whether the correct component has been installed and whether the component is arranged in the workpiece as specified. Additional parameters are preferably saved for documentation, such as target and/or actual processing parameters.

The tool preferably has a machining parameter specification device, wherein the data processing device outputs the intended machining parameters stored for the recognized and assigned machining point to the machining parameter specification device. The processing parameters are preferably screwing parameters, particularly preferably a predetermined torque and/or a predetermined angle of rotation, or riveting parameters, particularly preferably a predetermined force. These processing parameters with which the workpiece is processed, e.g. a screw is tightened, usually differ from processing point to processing point. The machining parameter specification device automatically specifies the parameters for the recognized machining location, so that the parameters do not have to be set elsewhere on the tool.

It is also advantageous if the tool has a release device that only releases processing with the tool if the processing point has been recognized and/or a memory entry has been created for documentation. As long as the tool is not released by the release device, the tool cannot be operated despite actuation of a trigger or despite switching on.

In an advantageous embodiment, the tool has a control device which regulates the tool so that the actual and target machining parameter values are brought into agreement. The control device thus monitors the machining process by measuring the actual parameter value during the machining process and comparing it with the target parameter value. As soon as the actual parameter value reaches the target parameter value, the machining process is stopped.

• - Erfassen eines Werkstücks mit Hilfe eines Werkzeugs mit einer Lichtlaufzeitkamera,
• - Verarbeiten der von der Lichtlaufzeitkamera ausgegebenen Daten, umfassend den Schritt des Vergleichens der von der Lichtlaufzeitkamera ausgegebenen Daten mit gespeicherten Daten von vorgegebenen Bearbeitungsstellen, wobei bei Übereinstimmung den ausgegebenen Daten die entsprechende vorgegebene Bearbeitungsstelle zugewiesen wird,
• - Erstellen eines Speichereintrages, wobei der Speichereintrag zumindest Informationen über die zugewiesene Bearbeitungsstelle, bevorzugt zusammen mit einer Zeitinformation, enthält.

To solve the problem, a method for machining a workpiece and for detecting machining points is also provided, comprising the steps:

• - Capturing a workpiece using a tool with a time-of-flight camera,
• - Processing the data output by the time-of-flight camera, comprising the step of comparing the data output by the time-of-flight camera with stored data from predetermined processing points, whereby if there is a match, the corresponding predetermined processing point is assigned to the output data,
• - Creating a memory entry, the memory entry containing at least information about the assigned processing point, preferably together with time information.

To solve the problem, the use of a tool with a time-of-flight camera for processing a workpiece, for recording processing points and for documenting the recording of the processing points is also provided. The documentation preferably includes the creation of storage entries that contain information about the recorded processing points together with time information about the time of recording the processing points or the creation of the storage processes themselves.

The description of the tool according to the invention and the method according to the invention, including the use according to the invention, are to be provided as complementary to one another, so that method steps that are explained in connection with the device are also to be understood individually or in combination as steps of the method according to the invention. Features of the device that are explained in connection with the method are also to be understood individually or combined with one another as features of the device according to the invention.

• 1 zeigt eine schematische Darstellung einer erfindungsgemäßen Ausführungsform eines Werkzeugs.
• 2 zeigt eine schematische Darstellung einer weiteren erfindungsgemäßen Ausführungsform eines Werkzeugs.
• 3 zeigt eine schematische Darstellung einer weiteren erfindungsgemäßen Ausführungsform eines Werkzeugs.
• 4 zeigt eine schematische Darstellung einer weiteren erfindungsgemäßen Ausführungsform eines Werkzeugs.

The invention is explained again below with reference to the figures.

• 1 shows a schematic representation of an embodiment of a tool according to the invention.
• 2 shows a schematic representation of a further embodiment of a tool according to the invention.
• 3 shows a schematic representation of a further embodiment of a tool according to the invention.
• 4 shows a schematic representation of a further embodiment of a tool according to the invention.

1 shows a schematic representation of an embodiment of a tool 1 according to the invention comprising a time-of-flight camera 2, which is placed on the tool 1. The tool further comprises a handle 3, which contains the drive unit and the accumulator, as well as a holding device 4.

2 shows a schematic representation of an embodiment according to the invention of a tool 1 comprising a time-of-flight camera 2, which is arranged integrated in the tool handle 3, the time-of-flight camera being arranged in the vicinity of the recording device 4 so that the workpiece area to be machined (not shown) is recorded.

3 shows a schematic representation of a further embodiment of a tool 1 according to the invention comprising a handle 3, a recording device 4 and a time-of-flight camera 2, which has a transmitter 5, a sensor 6 and control electronics 7.

4 shows a schematic representation of a further embodiment of a tool 1 according to the invention, comprising a handle 3, a recording device 4 and a time-of-flight camera 2, which has a transmitter 5, a sensor 6 and control electronics 7. The tool also includes a data processing device 8, a data memory 9, a processing parameter specification device 10 and a release device 11.

Reference symbol list

1

Tool

2

Time of flight camera

3

Handle

4

Recording device

5

Channel

6

sensor

7

Control electronics

8th

Data processing device

9

Data storage

10

Machining parameter specification device

11

Release facility

12

Control device

Claims (11)

Tool (1) for machining a workpiece and for detecting machining points, the tool (1) having a time-of-flight camera (2) with a transmitter (5) that emits light, an optical sensor (6) operating according to the time-of-flight method and control electronics (7 ), which controls the transmitter (5) and the optical sensor (6), the sensor (6) being constructed as a pixel array, characterized in that the tool (1) has a release device (11) which enables processing with the tool (1) is only released if the processing point has been recognized and a memory entry has been created for documentation. tool (1). Claim 1 , characterized in that the tool (1) is a hand-held tool, preferably a hand-held EC tool, particularly preferably a hand-held EC screwdriver. tool (1). Claim 1 or 2 , characterized in that the tool (1) is operated wirelessly. Tool (1) according to one of the Claims 1 until 3 , characterized in that the tool has a data processing device (8) and / or can access an externally arranged data processing device which processes the data output by the time-of-flight camera (2). Tool (1) according to one of the Claims 1 until 4 , characterized in that the tool (1) has a data memory (9) and / or can access an external data memory in which the data output by the data processing device (8) and / or by the time-of-flight camera (2), preferably together with a Time information can be saved. tool (1). Claim 4 or 5 , characterized in that the data processing device (8) compares the data output by the time-of-flight camera (2) with stored data from predetermined processing points and, if there is a match, assigns the data output by the time-of-flight camera (2) to the corresponding predetermined processing point and creates a memory entry. tool (1). Claim 6 , characterized in that the memory entry contains at least information about the recognized, assigned Processing point, preferably together with time information. Tool (1) according to one of the Claims 4 until 7 , characterized in that the tool has a machining parameter specification device (10), wherein the data processing device (8) outputs the intended machining parameters stored for the recognized, assigned machining point to the machining parameter specification device (10). Tool (1) according to one of the Claims 1 until 8th , characterized in that the tool (1) has a control device (12) which regulates the tool (1) so that the actual and target machining parameter values are brought into agreement. Method for machining a workpiece and for detecting machining points, comprising the steps, - Detecting a workpiece using a tool (1) with a time-of-flight camera (2) with an optical sensor (6) that works according to the time-of-flight method and is constructed as a pixel array, - Processing the data output by the time-of-flight camera (2), comprising the step of comparing the data output by the time-of-flight camera (2) with stored data from predetermined processing points, whereby if the output data matches, the corresponding predetermined processing point is assigned, - Creating a memory entry, the memory entry containing at least information about the recognized, assigned processing point, preferably together with time information. Use of a tool (1) with a time-of-flight camera (2) with an optical sensor (6) operating according to the time-of-flight method, which is constructed as a pixel array, for machining a workpiece, for detecting machining locations and for documenting the detection of the machining locations.

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