DE102019115559A1 - Gripping system for gripping processed parts and method for detecting whether a processed part has been cut - Google Patents

Abstract

The present invention relates to a gripping system for gripping parts of a workpiece that have been processed in a processing plant. The gripping system comprises a gripping arm, a gripping tool for lifting the processed parts from the workpiece. The gripping tool is arranged on the gripping arm. The gripping system also includes a control unit that communicates with the gripping system. The present invention also relates to a method for detecting whether a processed part has been completely cut from a workpiece processed in a processing system.

Description

The present invention relates to a gripping system for gripping parts of a workpiece processed in a processing system and a method for detecting whether a processed part of a workpiece processed in a processing system has been completely cut.

In the processing industry, in particular in the metal processing industry, a large proportion of the processing steps and / or manufacturing steps are carried out fully automatically. These steps also include the fully automatic loading and unloading of processing systems, especially cutting systems, which can reduce set-up times and maximize machine utilization. A transport unit can be used for loading and unloading the cutting systems, for example a changing table for transporting the raw material (workpiece) into the cutting system and a gripping system for unloading the parts cut from the workpiece after processing. In order to avoid malfunctions and / or downtimes in the cutting system, especially during unloading, it is necessary to check the processed (cut) parts for correct processing, in particular completely performed cuts, before unloading from the transport unit. An incomplete cut between the processed part and the workpiece, the so-called scrap skeleton, can lead to the processed part jamming when the processed part is gripped by the gripping system. The entire workpiece or scrap skeleton would be lifted by the transport unit, which can lead to a disruption of the gripping system and the processing plant.

Solutions known in the prior art provide for a check of the cuts between the processed part and / or the processed parts and the skeleton by means of an optical sensor, for example a surface scanner. Area scanners have the disadvantage that they are sensitive to external light radiation, for example sunlight, which can influence the measurement result or lead to a malfunction of the area scanner. In addition, when using area scanners to check remaining material webs (residual material in the case of an incomplete cut) between the processed part and the scrap skeleton, due to the way it works, it is necessary to lift the processed part to a specified height of at least 50 mm with a gripping system can be mapped and evaluated on the processed part via an area field generated by the area scanner. However, if there are material webs between the processed part and the scrap skeleton, raising the processed part to this predetermined height can lead to jamming and thus lifting of the entire scrap skeleton. The position of the skeleton on the transport unit can be changed in this regard, so that further processed parts can no longer be gripped / lifted off. The unloading process is disrupted and the entire processing plant can go into a fault state, which leads to a loss of production and increased production costs. In addition, the other processed parts can be damaged. Furthermore, the lifting to the specified height and the checking must be carried out for each processed part of the processed workpiece, which increases the processing time of the processing plant and reduces productivity and machine utilization.

It is therefore the object of the present invention to ensure trouble-free checking of the processed parts of the workpiece and to at least partially overcome the disadvantages known in the prior art.

This object is achieved according to the invention by a gripping system for gripping parts of a workpiece processed in a processing system and by a method for detecting whether a processed part of a workpiece processed in a processing system is completely cut with the features specified in the mutually dependent claims.

• - mit einem Greifarm;
• - mit einem Greifwerkzeug zum Anheben der verarbeiteten Teile aus dem Werkstück, wobei das Greifwerkzeug an dem Greifarm angeordnet ist;
• - mit einer Steuereinheit, die mit dem Greifsystem kommuniziert und insbesondere das Greifwerkzeug und/oder den Greifarm steuert.

According to a first aspect, the invention accordingly creates a gripping system for gripping parts of a workpiece that are processed in a processing system:

• - with a gripper arm;
• with a gripping tool for lifting the processed parts from the workpiece, wherein the gripping tool is arranged on the gripping arm;
• - With a control unit which communicates with the gripping system and in particular controls the gripping tool and / or the gripping arm.

In the context of the present invention, a processing system is to be understood as a cutting system, in particular a laser cutting system. The laser cutting system comprises the actual laser cutting unit in which a workpiece or a workpiece to be processed, for example a sheet metal, is processed into individual parts, for example cut into individual sheet metal parts or from which individual contours are cut out. In addition, the processing system can have a transport system, for example a transport unit for transporting the workpiece from a loading and unloading Include discharge area into and out of the laser cutting unit. The transport unit can be designed as a transport table. The transport table can be moved into and out of the laser cutting system. The workpiece (sheet metal) to be processed lies on the transport table from which the parts to be processed (individual contours) are cut out by the laser cutting system. In addition, a transport unit can be understood to mean a changing table in one embodiment. A shuttle table comprises two separate tables stacked on top of each other, which run on two guide levels and which can be moved separately. This has the advantage that a workpiece is processed on a first table in the processing system and a workpiece that has already been processed and transported on the second table can be unloaded. In an advantageous manner, a new workpiece can be processed and a previously processed workpiece or processed parts can be transported away at the same time.

The present invention is based on the knowledge that there is a need for an improved inspection of the cuts between the processed parts and the workpiece, prior to the actual lifting of the processed parts by the gripping system. Advantageously, the processed parts can be checked for contact with the workpiece before they are actually lifted. This contact represents a material connection, for example a material web between the processed part and the workpiece, which is recognized before lifting, which avoids tilting or catching of the processed part during lifting and thus the entire workpiece or the scrap skeleton the transport unit is not moved. The processing plant and the entire processing process are therefore less prone to failure. In addition, the process time for checking the processed parts is advantageously reduced, since the present invention can detect at any time whether the processed part is still in contact with the workpiece or the scrap skeleton and the transport unit (material web, so-called microjoint ) stands as soon as the gripping tool touches the processed part.

Advantageous embodiments and developments emerge from the subclaims and from the description with reference to the figures.

In an advantageous embodiment, the gripping system has an analog input which is designed to receive an analog electrical signal. An analog electrical signal can advantageously be received by the gripping system. An electrical voltage can be applied to the analog input, which can advantageously be evaluated for its voltage value. The evaluated voltage value can be used for driving or controlling electronic units.

In an advantageous embodiment, the control unit comprises a detector unit which has a 0 volt potential and which is designed to detect a voltage drop at the analog input. In the context of the present invention, a voltage drop is understood to mean the reduction from a previously applied voltage value to a lower voltage value caused by an event. The detector unit can be designed, for example, as a measuring device, in particular a voltage measuring device, via which a voltage or an applied or falling voltage can be determined. The voltmeter is connected in parallel to a consumer, component or voltage source. When measuring at the voltage source, the current voltage value is measured. The voltage drop at one consumer is measured at this one consumer. This voltage drop corresponds to a partial voltage of the total voltage of the voltage source. In order not to influence the circuit to be measured, the internal resistance of the voltage measuring device should be as high as possible. An infinitely high internal resistance would be ideal. In an advantageous manner, a voltage drop with reference to an identical potential can thus be determined and evaluated. In an advantageous embodiment, the detector unit is designed as an analog input card of the control unit. The analog input card can be configured to be configurable, so that it has a different functional behavior / output behavior in response to changing voltage drops.

In an advantageous embodiment, the gripping system is a gripping robot. In the context of the present invention, a gripping robot is to be understood as a universal, programmable machine for handling processed parts. The gripping system can be designed as a gripping robot with several differently controllable axes with separate drive units. The drive units can include electrical, pneumatic and / or hydraulic drives. With a gripping robot, a work sequence can be carried out autonomously, precisely and at high speed, exactly repeatable and automatically. The gripping system can comprise one or more gripping tools. The gripping tools are interchangeable and can be exchanged or changed automatically by the gripping system or by manual input.

In an alternative embodiment, the gripping system can be a Cartesian Be trained robot system. The Cartesian robot system comprises linear drives and can be designed as a two- or three-axis Cartesian robot system.

In an advantageous embodiment, the gripping tool comprises at least one electrically conductive gripping tool. In the context of the present invention, an electrically conductive gripping tool is to be understood as a gripping tool with which objects can be gripped or held and transported from a first position to a second position by the gripping system. The electrically conductive gripping tool is designed such that it conducts an electrical current. In an advantageous manner, the electrically conductive gripping tool can thus be connected to a voltage source via an electrical connection, for example an electrical line. The electrically conductive gripping tool has a resistor with a specific, material-dependent resistance value, as a result of which a voltage drops across the electrically conductive gripping tool when a current flows through the electrically conductive gripping tool. The resistance value is also dependent on the size of the electrically conductive gripping tool.

In an advantageous embodiment, the gripping tool can be exchanged in a modular manner. In an advantageous manner, processed parts of the most varied shape, size, mass, material and / or material thickness can thus be gripped and transported with a gripping tool designed for this purpose. The gripping system can have a storage / changing station for storing and changing a large number of modular, exchangeable gripping tools.

In an advantageous embodiment, the electrically conductive gripping tool is designed as an electrically conductive suction cup, preferably as an electrically conductive vacuum suction cup. In an advantageous manner, electrically conductive suction cups are available in different materials with different Shore hardnesses, so that a corresponding suction cup can be selected and used for each processed part with the most varied of shape, size, mass, material and / or material thickness. The electrically conductive vacuum suction cup forms the interface or interfaces to the processed part. The electrically conductive vacuum suction device can have a round and an oval design. The round, electrically conductive vacuum suction cup is suitable for handling flat workpieces. The oval, electrically conductive vacuum suction cup can be used for narrow, elongated workpieces. In one embodiment, the electrically conductive vacuum suction cup can be designed as a flat suction cup or a bellows suction cup. Flat suction cups have the advantage of a low overall height and a small internal volume. The small volume ensures short blow-off times. In addition, flat suction cups in this design have good inherent stability and ensure high positional accuracy. Flat suction cups can be used in highly dynamic processes. Bellows suction cups with one or more bellows have the advantage that height differences can be compensated for. The bellows also provides a damping effect when the gripping system touches the part of the processed workpiece. Sensitive parts of the processed workpiece can be gripped gently with a bellows suction cup. In a further embodiment, the electrically conductive vacuum suction device can be designed as a flat suction device with a spring plug. The height can advantageously be compensated for.

In one embodiment, the electrically conductive vacuum suction cup has a diameter of 40 mm, 50 mm, 60 mm or 80 mm. As the size changes, the resistance value of the electrically conductive vacuum suction device also changes.

In one embodiment, the electrically conductive gripping tool can have a plurality of vacuum suction cups, in which one vacuum suction device is designed as an electrically conductive vacuum suction cup. In this way, processed parts with a wide variety of shapes, sizes, dimensions, materials and / or material thicknesses can be sucked in (gripped).

In a further embodiment, the electrically conductive gripping tool can have a plurality of vacuum suction cups, in which at least two vacuum suction cups are designed as electrically conductive vacuum suction cups. In this way, processed parts with a wide variety of shapes, sizes, dimensions, materials and / or material thicknesses can be sucked in (gripped). Furthermore, the functionality of the electrically conductive vacuum suction device is designed in a redundant manner.

In an advantageous embodiment, the at least one electrically conductive vacuum suction device lifts the processed parts by the lifting height of the vacuum suction device out of the workpiece. The lifting height represents the height at which the processed part is lifted or gripped from the workpiece when a vacuum is applied. The height corresponds to the suction volume of the electrically conductive vacuum suction device, in particular the height corresponds to the movement potential of the suction device material up to the suction nozzle. The electrically conductive vacuum suction device is used to grab the processed part from the workpiece and move it. The electrically conductive vacuum suction cup does not stick to the part, but the ambient pressure (atmospheric pressure) presses the part against the electrically conductive vacuum suction cup or the electrically conductive vacuum suction cup against the processed part of the processed workpiece. For this, the surrounding pressure (ambient pressure) must be higher than the pressure between the electrically conductive vacuum suction device and the processed part. This pressure difference can be achieved by connecting the electrically conductive vacuum suction cup to a vacuum generator. The vacuum generator sucks the air between the electrically conductive vacuum suction cup and the processed part. The air is thus evacuated. As soon as there is contact between the electrically conductive vacuum cup and the surface of the processed part and the electrically conductive vacuum cup seals the workpiece surface against the ambient pressure, the necessary negative pressure is generated. The holding force of an electrically conductive vacuum suction cup is obtained by multiplying the pressure difference with the effective suction area of the electrically conductive vacuum suction cup. The holding force F results from the following formula: $$\text{F =}\Delta \text{p}\times \text{A.}\text{.}$$

The parameter Δp is the difference between the ambient pressure and the system pressure and the parameter A is the effective suction area (which is subjected to a vacuum, the effective area of an electrically conductive vacuum suction device). The holding force F is therefore proportional to the pressure difference and the area. The holding force F is greater, the greater the difference between ambient pressure and pressure in the electrically conductive vacuum suction cup or the greater the effective suction area. The holding force F can be varied by changing the parameters pressure difference and area.

In an advantageous embodiment, the electrically conductive gripping tool can be connected to a voltage source, in particular a direct voltage source. The electrically conductive gripping tool is advantageously conductive and has a resistance, as a result of which a voltage on the conductive gripping tool drops in the event of a closed electrical circuit. This voltage drop can be detected and measured.

In an advantageous embodiment, the voltage source provides a voltage in a range from 0.1 to 24 volts, in particular in a range from 8 to 12 volts, preferably from 10 volts to the electrically conductive gripping tool. In an advantageous manner, safely reduced voltages in a range from 0.1 to 24 volts can be applied to the electrically conductive gripping tool via a voltage source. The safely reduced voltages are preferably reduced via a voltage divider in such a way that 10 volts are applied to the analog input and, in parallel, to the electrically conductive gripping tool. Here, safely reduced voltages are to be understood as those voltages that are present in electrical systems through a corresponding type of protective separation of different voltage levels. A distinction is made between safety extra-low voltage (SELV), functional extra-low voltage with electrically safe separation (PELV) and functional extra-low voltage without electrically safe separation (FELV).

In an advantageous embodiment, the analog input can be connected to the same voltage source parallel to the electrically conductive gripping tool. The analog input is advantageously connected to the same voltage source in parallel with the electrically conductive gripping tool. Thus, the voltage provided by the voltage source at the analog input drops as long as there is no electrical connection between the processed part and the workpiece. If there is an electrically conductive connection between the processed part and the workpiece and the electrically conductive gripping tool grips the processed part, a current flows from the electrically conductive gripping tool via the processed part to the workpiece, which is connected to the transport unit. The transport unit has the corresponding ground potential for this. By connecting the electrically conductive gripping tool and the analog input to a common voltage source in parallel, a voltage drop at the analog input can be generated and detected in the event of a faulty cut of the processed part.

In an advantageous embodiment, the workpiece with the processed parts is stored on a transport unit of the processing system and the transport unit has the same potential as the detector unit. In an advantageous manner, a current flow is thus established via the electrically conductive gripping tool when there is an electrically conductive connection between the processed part and the workpiece and the electrically conductive gripping tool is in contact with the processed part. A voltage drop can be detected by the same potential of the detector unit, including the analog input.

In an advantageous embodiment, the detector unit detects a voltage drop at the analog input if a processed part has an electrical connection to the workpiece. In the context of the present invention, a voltage drop is understood to mean the reduction from a previously applied voltage value to a lower voltage value caused by an event. In this way, a faulty processed part can advantageously be recognized. The event can, for example, represent the electrical connection between the processed part and the workpiece, as well as the transport unit.

• - Erfassen des Werkstücks mit verarbeiteten Teilen auf der Transporteinheit der Verarbeitungsanlage;
• - Anheben eines verarbeiteten Teils des Werkstücks mit einem Greifwerkzeug eines Greifsystems; und
• - Detektieren eines Spannungsabfalls an einem analogen Eingang des Greifsystems, falls ein verarbeitetes Teil eine elektrische Verbindung zu dem Werkstück aufweist.

According to a further aspect, the invention creates a method for detecting whether a processed part is completely cut from workpieces processed in a processing plant, with the following process steps:

• - Detecting the workpiece with processed parts on the transport unit of the processing plant;
• - Lifting a processed part of the workpiece with a gripping tool of a gripping system; and
• - Detecting a voltage drop at an analog input of the gripping system if a processed part has an electrical connection to the workpiece.

In an advantageous embodiment, the gripping tool comprises at least one electrically conductive gripping tool that can be connected to the analog input.

In an advantageous embodiment of the method, the electrically conductive gripping tool is designed as an electrically conductive suction cup, preferably as an electrically conductive vacuum suction cup.

The invention also provides a computer program with program code for controlling a method according to one of the preceding method claims when the computer program is executed on an electronic device. The computer program can be provided as a signal by download or stored in a memory unit of a portable device with the computer-readable program code contained therein in order to cause a gripping system to execute instructions according to the above-mentioned method. The implementation of the invention by means of a computer program product has the advantage that existing electronic devices, for example computers, portable devices, can easily be used by software updates in order, as proposed by the invention, to detect whether a processed part has been processed in a processing system Workpiece is completely cut to allow.

The computer program can be executed in a distributed manner so that, for example, individual method steps are executed on a first processing unit and other method steps are executed on a second processing unit.

The above configurations and developments can be combined with one another as desired, provided that it makes sense. Further possible configurations, developments and implementations of the invention also include combinations, not explicitly mentioned, of features of the invention described above or below with regard to the exemplary embodiments. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

Figure list

• 1 ein Blockdiagramm zur Darstellung eines möglichen Ausführungsbeispiels eines erfindungsgemäßen Greifsystems;
• 2 ein Ablaufdiagramm zur Darstellung eines möglichen Ausführungsbeispiels eines erfindungsgemäßen Verfahrens;
• 3 ein Blockdiagramm zur Darstellung eines weiteren möglichen Ausführungsbeispiels eines erfindungsgemäßen Greifsystems;
• 4 ein Blockdiagramm zur Darstellung eines weiteren möglichen Ausführungsbeispiels eines erfindungsgemäßen Greifsystems.

In the following detailed description of the figures, non-restrictive exemplary embodiments with their features and further advantages are discussed with reference to the drawing. It shows:

• 1 a block diagram to illustrate a possible embodiment of a gripping system according to the invention;
• 2 a flow chart to illustrate a possible embodiment of a method according to the invention;
• 3 a block diagram to illustrate a further possible embodiment of a gripping system according to the invention;
• 4th a block diagram to illustrate a further possible embodiment of a gripping system according to the invention.

The accompanying drawings are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the advantages mentioned emerge with a view to the drawings. The elements of the drawings are not necessarily shown to scale with one another.

In the figures of the drawing, identical, functionally identical, and identically acting elements, features and components - unless otherwise stated - are each provided with the same reference symbols.

Detailed description of the invention

1 shows a block diagram to illustrate a possible embodiment of a gripping system according to the invention 10 . In 1 denotes reference numerals 10 the gripping system according to the present invention. The gripping system 10 is designed to be a processed part 41 (see. 4th ) of a workpiece 40 to grab and, for example, to transport to another transport system and store it. The workpiece 40 , for example a sheet metal, is in a processing plant 30th processed. In one embodiment, the processing facility comprises 30th a Laser cutting machine in which a processed part 41 , for example a contour from the workpiece 40 is cut. The workpiece 40 can have different sheet thicknesses and / or sheet metal areas with different external dimensions according to the processing plant 30th Include that by the processing plant 30th can be processed. From one workpiece 40 a contour or a large number of contours can be cut.

The workpiece 40 is used for processing on a transport unit 31 filed. The transport unit 31 can for processing the workpiece 40 into the processing plant 30th and for the removal of the processed part 41 from the transport unit 31 from the processing plant 30th be driven out. In one embodiment, the transport unit is 31 designed in redundant form as a shuttle table. This enables a workpiece to be processed at the same time 40 in the processing plant 30th and the unloading of a previously processed item of value 40 through the gripping system 10 . Here, the tables of the changing table are exchanged outside the processing plant 30th such that the already unloaded table is outside the processing plant 30th is lowered and the table with the processed workpiece 40 from the processing plant 30th is moved over the lowered shuttle table. Both tables located outside the processing plant are raised and the processed parts are unloaded by the gripping system 10 . The lower table is in the processing plant 30th move and a previously placed new workpiece 40 can be inside the processing plant 30th are processed. This is only an exemplary and not a restrictive embodiment of the changing table and its movement sequences. Rather, further sequences with possibly further and / or different steps are conceivable, for example without changing table with a different type of transport unit.

The gripping system 10 can be designed as a gripping robot. In one embodiment, the gripping system 10 a gripper arm 11 on. In an advantageous embodiment, the gripping system 10 at least one gripper arm 11 with several axes that can be controlled differently from one another. Due to the different axes, the mobility, precision and the range of the gripping system 10 increase.

The gripping system 10 has a gripping tool 12th for lifting the processed parts 41 from the workpiece 40 on. The gripping tool 12th is on the gripper arm 11 of the gripping system 10 arranged. In an advantageous embodiment, the gripping tool is 12th as a modular, interchangeable gripping tool 12th educated. In one embodiment, the gripping system 10 a gripping tool change system in which predefined gripping tools are stored in accordance with specific requirements, activities and / or work processes. The gripping system 10 can automatically change the gripping tool according to the requirements, activities and / or work processes 12th carry out.

The gripping system 10 has a control unit 13th on that with the gripping system 10 communicates. A control unit 13th refers to any electronic device that includes a processor, such as a main processor (CPU), special purpose processor, or microcontroller. The processor is adapted to carry out a special computing task, namely to detect a voltage drop. The control unit 13th can receive data (an input), then perform a sequence of predetermined operations and thereby generate a result in the form of information or signals (an output). Depending on the context, the computing unit means either a processor or, more generally, may refer to a processor in connection with an assembly of interconnected elements contained in a single housing or cases. In one embodiment, the control unit 13th as a programmable logic controller (PLC) or software implementation of a PLC on a processor. Furthermore, the control unit 13th run as one instance on another system.

In one embodiment, the control unit 13th a detector unit 15th on. In one embodiment, the detector unit 15th be designed as a voltage measuring device via which a falling voltage can be determined. In one embodiment, the detector unit 15th continue to have an analog input card (not shown) connected to the analog input 14th for evaluating the voltage drop at the analog input 14th connected is. The analog input 14th is designed to receive an analog electrical signal, in particular a DC voltage signal. The analog electrical signal is evaluated by the analog input card and can be converted into a digital signal that can be used for control purposes by an analog-digital conversion integrated on the analog input card using an AD converter. This usable digital signal can be used to control the processing plant according to the value 30th and / or for display to an operator of the processing plant 30th be used. In one embodiment, these are analog inputs 14th and the detector unit 15th in the gripping system designed as a gripping robot 10 integrated and the control unit 13th is an external component that has a communication link with the gripping system 10 communicates, educated. This has the advantage that the voltage losses in the connecting lines, especially between the electrically conductive gripping tool and the analog input 14th or detector unit 15th can be minimized or limited. Lines that are too long lead to an increased voltage drop on the connecting lines, which leads to the detection of the voltage drop at the analog input 14th falsified and can lead to a measurement error.

In addition, the gripping system 10 a voltage supply via a voltage source 20th , in particular via a DC voltage source. The voltage source 20th can provide a voltage in a voltage range of 0.1 to 20 volts, in particular in a range of 8 to 12 volts, preferably 10 volts. In embodiments with a voltage higher than 10 volts, the 10 volt voltage can be provided via a voltage divider. The voltage source 20th is with the electrically conductive gripping tool 12th connected. The voltage source 20th is also parallel to the electrically conductive gripping tool 12th on the analog input 14th switched. Preferably, both on the electrically conductive gripping tool 12th and the analog input 14th a DC voltage of 10 volts was applied.

In one embodiment, the detector unit 15th and the transport unit 31 an equal ground potential. Has a processed part 41 an electrical connection 50 (see. 4th ) over a material web (residual material in the case of a faulty cut), the ground potential of the transport unit lies 31 over the workpiece 40 on the processed part 41 even at the moment when the electrically conductive gripping tool 12th the processed part 41 has increased above the height of the suction volume. This leads to a voltage drop of 10 volts at the analog input, which can be evaluated in an advantageous manner and information about the corresponding processed part to be lifted 41 provides, for example which part processed 41 of the workpiece 40 is flawed.

The gripping system 10 has a gripping tool 12th on. In one embodiment, the gripping tool comprises 12th at least one electrically conductive gripping tool 12th . The electrically conductive gripping tool 12th is made of a material that conducts the electric current and has an electrical resistance with a resistance value. The resistance depends on the material and size of the electrically conductive gripping tool 12th from.

In one embodiment the electrically conductive gripping tool 12th of the gripping system 10 modular interchangeable. In the context of the present invention, modular is to be understood as meaning that different gripping tools correspond to the requirements for size and weight of the processed parts to be lifted 41 , as well as the type and area of use are interchangeable.

The electrically conductive gripping tool 12th comprises an electrically conductive suction cup, preferably an electrically conductive vacuum suction cup. In one embodiment, the electrically conductive gripping tool comprises 12th at least one teat or a plurality of teats and one electrically conductive teat or a plurality of electrically conductive teats. In an advantageous manner, differently processed parts can thus 41 to be raised with different requirements. There is also redundancy for the electrically conductive vacuum cleaner and for the voltage drop at the analog input 14th in front. This is an advantage if you have a second analog input 14th and a second analog input card is present. This results in redundant monitoring of the measurement and evaluation of the voltage drop.

2 shows a flow chart to illustrate a possible embodiment of a method according to the invention.

The procedure 1 comprises several steps in the illustrated embodiment. In a first step S1, the workpiece 40 with the processed parts 41 on one to the processing plant 30th belonging transport unit 31 detected. Step S1 takes into account those from the processing facility 30th provided cutting information of the processed parts 41 , for example a cutting plan. Thus, the positions of the processed parts are 41 which are to be transported away.

In a further step S2, a processed part is raised 41 of the workpiece 40 with a gripping tool 12th a gripping system 10 . In one embodiment of the present invention, the gripping tool comprises 12th an electrically conductive gripping tool, in particular an electrically conductive suction device, preferably an electrically conductive vacuum suction device. For the purposes of the present invention, lifting is the lifting of a processed part 41 by the height of lift of the suction cup from the workpiece 40 to understand. In one embodiment, the stroke height corresponds to a suction volume of the vacuum suction device.

In a further step S3 there is a voltage drop at an analog input 14th of the gripping system 10 detected if a processed part 41 an electrical connection 50 (see. 4th ) to the workpiece. The voltage drop at the analog input 14th can then be detected when the electrically conductive gripping tool 12th the processed part 41 from the workpiece 40 raises. The detected voltage change can trigger a message.

3 shows a block diagram to illustrate a further possible embodiment of a gripping system according to the invention 10 . In 3 is a gripping system 10 shown by an electrically conductive gripping tool 12th , preferably a processed part by an electrically conductive vacuum suction device 41 from the workpiece 40 raises. The gripping system 10 conducts the procedure 1 (see. 2 ) according to the present invention. The electrically conductive vacuum suction cup 12th has a resistance value. The resistance value of the electrically conductive vacuum cup 12th can be measured. On the electrically conductive vacuum suction cup 12th can apply a voltage across the voltage source 20th (see. 1 ), preferably of 10 volts. The voltage of 10 volts of the voltage source 20th is parallel to an analog input 14th created. The analog input 14th has a connection to a detector unit 15th to detect the voltage drop. In one embodiment, the detector unit comprises 15th an analog input card. The transport unit 31 and the detector unit 15th have a ground potential. When the electrically conductive vacuum suction device 12th contact with the transport unit during lifting 31 gets over a processed part 41 that with the workpiece 40 is in electrical contact, the voltage at the analog input breaks 14th at an originally applied voltage of, for example, 10 volts to 2 volts. If now, as in 3 shown, the processed part 41 through the electrically conductive vacuum suction device 12th is sucked in or raised and there is no contact between the processed part 41 and the workpiece 40 and thus the transport unit 31 exists, the 10 volts are still at the analog input 14th and are measurable and evaluable.

4th shows a block diagram to illustrate a further possible embodiment of a gripping system according to the invention 10 . In 4th is a gripping system 10 shown by an electrically conductive gripping tool 12th , preferably an electrically conductive vacuum suction cup a processed part 41 from the workpiece 40 raises. The gripping system 10 conducts the procedure 1 (see. 2 ) according to the present invention. On the electrically conductive vacuum suction cup 12th can apply a voltage across the voltage source 20th (see. 1 ), preferably of 10 volts. The voltage of 10 volts of the voltage source 20th is parallel to an analog input 14th created. The analog input 14th has a connection to a detector unit 15th to detect the voltage drop. In one embodiment, the detector unit comprises 15th an analog input card. The transport unit 31 and the detector unit 15th have a ground potential. When the electrically conductive vacuum suction device 12th Contact to the transport unit 31 about one with the workpiece 40 processed part in electrical contact 41 while it is being raised, the voltage at the analog input breaks 14th at an originally applied voltage of, for example, 10 volts to 2 volts. If now, as in 4th shown, the processed part 41 through the electrically conductive vacuum suction device 12th is sucked or raised and an electrical contact or an electrical connection 50 between the processed part 41 and the workpiece 40 and thus the transport unit 31 exists, the one at the analog input breaks 14th previously applied 10 volts voltage, for example to a voltage value of 2 volts. This voltage drop is through the detector unit 15th evaluable and appropriate measures can be implemented. For example, the gripping system 10 Issue a fault message or warning and indicate which part has been processed 41 an electrical connection 50 to the workpiece 40 having.

In an advantageous embodiment, the analog input is 14th configurable. The analog input 14th can be configured to changing values for the voltage drop, which are due to the conductivity value of different materials for the parts to be processed 41 can result. For example, copper has a better conductivity coefficient than steel, making copper a better conductor than steel. In this regard, the voltage drop with a 10 volt output voltage for copper is higher than that for steel. The higher voltage drop can be achieved through the configurable input 14th are specified, whereby different types of material can be checked with the present invention.

Finally, it should be pointed out that the description of the invention and the exemplary embodiments are in principle not to be understood as restrictive with regard to a specific physical implementation of the invention. All the features explained and shown in connection with individual embodiments of the invention can be provided in different combinations in the subject matter of the invention in order to simultaneously realize their advantageous effects.

The scope of protection of the present invention is given by the claims and is not restricted by the features explained in the description or shown in the figures.

List of reference symbols

1

Procedure

10

Gripping system

11

Gripper arm

12

Gripping tool

13th

Control unit

14th

analog input

15th

Detector unit

20th

Voltage source

30th

Processing plant

31

Transport unit

40

workpiece

41

processed parts

50

electrical connection

S1-S3

Procedural steps

Claims (18)

Gripping system (10) for gripping parts (41) of a workpiece (40) processed in a processing system (30) - At least one gripping arm (11); - At least one gripping tool (12) for lifting the processed parts (41) out of the workpiece (40), the gripping tool (12) being arranged on the gripping arm (11); - A control unit (13) which communicates with the gripping system (10). Gripping system (10) according to the immediately preceding claim, wherein the gripping system (10) has an analog input (14) which is designed to receive an analog electrical signal. Gripping system (10) according to the immediately preceding claim, wherein the control unit (13) comprises a detector unit (15) which has a 0 volt potential and which is designed to detect a voltage drop at the analog input (14). Gripping system (10) according to one of the preceding claims, wherein the gripping system (10) is a gripping robot. Gripping system (10) according to one of the preceding claims, wherein the gripping tool (12) comprises at least one electrically conductive gripping tool (12). Gripping system (10) according to one of the preceding claims, wherein the gripping tool (12) is modularly exchangeable. Gripping system (10) according to the immediately preceding claim, wherein the electrically conductive gripping tool (12) is designed as an electrically conductive suction device, preferably as an electrically conductive vacuum suction device. Gripping system (10) according to the immediately preceding claim, wherein the electrically conductive vacuum suction device lifts the processed parts by the lifting height of the vacuum suction device from the workpiece. Gripping system (10) according to the immediately preceding claim, wherein the lifting height corresponds to a suction volume of the vacuum suction device. Gripping system (10) according to one of the preceding Claims 5 to 9 wherein the electrically conductive gripping tool (12) can be connected to a voltage source (20), in particular a direct voltage source. Gripping system (10) according to the immediately preceding claim, wherein the voltage source (20) applies a voltage in a range from 0.1 to 24 volts, in particular in a range from 8 to 12 volts, preferably from 10 volts to the electrically conductive gripping tool (12 ) provides. Gripping system (10) according to one of the preceding Claims 5 to 8th , wherein the analog input (14) can be connected to the same voltage source (20) parallel to the electrically conductive gripping tool (12). Gripping system (10) according to the immediately preceding claim, wherein the workpiece (40) with the processed parts (41) is stored on a transport unit (31) of the processing system (30) and the transport unit (31) has the same potential as the detector unit ( 15). Gripping system (10) according to the immediately preceding claim, wherein the detector unit (15) detects a voltage drop at the analog input (14), if a processed part (41) has an electrical connection (50) to the workpiece (40). Method for detecting (1) whether a processed part (41) of workpieces (40) processed in a processing system (30) has been completely cut, with the following process steps: - Detecting (S1) the workpiece (40) with processed parts (41) on a transport unit (31) of the processing installation (30); - Lifting (S2) a processed part (41) of the workpiece (40) with a gripping tool (12) of a gripping system (10); and - Detecting (S3) a voltage drop at an analog input (14) of the gripping system (10) if a processed part (41) has an electrical connection (50) to the workpiece (40). Method according to the immediately preceding method claim, wherein the gripping tool (12) comprises at least one electrically conductive gripping tool (12) which can be connected to the analog input (14). Method according to the immediately preceding method claim, wherein the electrically conductive gripping tool (12) is designed as an electrically conductive suction device, preferably as an electrically conductive vacuum suction device. Computer program with program code for controlling a method (1) according to one of the preceding method claims, when the computer program is executed on an electronic device.

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