METHOD AND DEVICE FOR MONITORING A PROCESS

Description

[0001] The invention relates to a method for monitoring a machining process in which a workpiece is continuously machined along at least one predetermined machining path on the workpiece using a machining tool arranged on a collaborative robot during at least one machining period, wherein the environment of the collaborative robot is monitored and an object in a manipulation area of ​​the collaborative robot around one of the predetermined machining paths on the workpiece is detected, and in the event of the detection of an object in the manipulation area of ​​the collaborative robot around one of the predetermined machining paths on the workpiece within an instruction phase, an instruction signal is issued and the machining process along one of the predetermined machining paths on the workpiece is continued without interruption.wherein an instruction signal is issued to the collaborative robot to replan the processing process, and according to the issued instruction signal, in the event of the detection of an object in the manipulation area around one of the predetermined processing paths of the collaborative robot, the processing process is changed by changing the sequence of the predetermined processing paths.

[0002] The invention further relates to a device for monitoring a machining process in which a workpiece can be continuously machined along at least one machining path on the workpiece using a machining tool arranged on a collaborative robot during at least one machining period, comprising a sensor device for monitoring the environment of the collaborative robot and a detection device for detecting an object in a manipulation area of ​​the collaborative robot around one of the predetermined machining paths on the workpiece, wherein the detection device is connected to a device for outputting an instruction signal within an instruction phase in the event of the detection of an object in the manipulation area of ​​the collaborative robot around one of the predetermined machining paths on the workpiece.so that the machining process along one of the predetermined machining paths on the workpiece can be continued without interruption, wherein the device for outputting an instruction signal is formed by a device for outputting an instruction signal to the collaborative robot for replanning the machining process, in accordance with the output instruction signal, in the event of the detection of an object in the manipulation area around one of the predetermined machining paths of the collaborative robot, the machining process is changed by changing the sequence of the predetermined machining paths.

[0003] Finally, the invention is also directed to a processing machine, in particular a welding device, with a collaborative robot for the continuous processing of a workpiece during at least one processing period along at least one processing path.

[0004] A collaborative robot, or cobot, is an industrial robot that works alongside humans and is not separated from them by safety devices during the processing process. The safety requirements for collaborative robots are defined in relevant standards and stipulate that collisions between robots and humans must be prevented to protect people. For this purpose, the robots are equipped with appropriate sensors, and certain sensor signals trigger an automatic shutdown of the robot. For example, US 5,952,796 A describes such a collaborative robot.

[0005] Methods for planning machining processes involving collaborative robots, in order to achieve maximum machining speeds on the one hand and to minimize the risk of injury to persons involved on the other, are described in the prior art, for example in WO 2015 / 049207 A2.

[0006] US 2015 / 0112483 A1 and US 2018 / 0297201 A1 describe handling procedures in which pallets are loaded using a robot and certain zones within the robot's area are monitored. This prior art does not involve machining processes on a workpiece, nor does it utilize a collaborative robot capable of working alongside humans without safety precautions.

[0007] WO 2014 / 048444 A1 and US 2018 / 222051 A1 also describe the operating mode of a collaborative robot.

[0008] In machining processes where the movement of the collaborative robot is an integral part of the process, the prescribed safety measures for collaborative robots are not always easily applicable. The standard safety measure for the collaborative robot is to stop its movement, which is equivalent to interrupting the machining process and negatively impacting manufacturing quality. Examples of such machining processes, where the movement of the collaborative robot is part of the manufacturing process, include welding or soldering, painting, bonding, and surface treatment, to name a few. During the machining process, the workpiece can also be moved in a controlled manner, either in addition to or instead of the collaborative robot, and does not necessarily have to be stationary.When the workpiece is moved, the device that causes the movement of the workpiece is subject to the same rule as a collaborative robot.

[0009] The present invention relates to such machining processes in which predetermined machining paths are to be processed continuously over at least one processing period, and in order to achieve the highest possible machining quality, the processing of these machining paths should not be interrupted during the processing periods. The formation of one or more weld seams on a workpiece is mentioned as an example of such a machining process. If the continuous processing of a machining path, for example the formation of a weld seam, were interrupted by the automatic shutdown of the collaborative robot, the processing would have to be continued at the point of interruption, which could lead to a loss of quality or even to the rejection of the workpiece.

[0010] The object of the present invention is to provide the aforementioned method and device for monitoring a machining process and a machining machine with such a monitoring device, enabling the machining process to proceed with as few interruptions as possible. Disadvantages of known methods are to be reduced or avoided.

[0011] The problem according to the invention is solved in terms of method by issuing an instruction signal to the collaborative robot to replan the machining process, and in accordance with the issued instruction signal, in the event of the detection of an object in the manipulation area around one of the predetermined machining paths of the collaborative robot, the machining process is changed by changing the sequence of the predetermined machining paths.The present invention provides for the timely detection of whether an object is present in the manipulation area of ​​a collaborative robot's processing path. This allows for timely intervention before the collaborative robot automatically shuts down, enabling measures to be taken to remove the object from the manipulation area, allow the object (if it is a person) to move out of the manipulation area, or replan the processing accordingly so that the detected object no longer poses an obstacle for the collaborative robot, allowing the processing process to continue. The term "object" encompasses all objects or persons with which parts of the collaborative robot could collide. The term "manipulation area" refers to the area along the collaborative robot's processing path within which collisions are possible during the processing process.Depending on the type of collaborative robot, this can involve a small area around the machining path or a larger area that also takes into account the robot's axes and their movement capabilities. By outputting an instruction signal according to the invention upon detection of an object in the manipulation area of ​​a machining path, it is thus possible to ensure that the object is removed from the manipulation area in a timely manner or that the machining process is modified accordingly, so that the machining process can continue. Should the measures to remove the object or replan the machining process fail, the usual protective measures, i.e., generally stopping the robot's movement, are of course carried out as before to comply with the relevant standards and to prevent endangering personnel or damaging the machining equipment or the workpiece.A change or replanning of the machining process can be achieved in various ways, for example, by machining the same machining path in whose manipulation area the object was detected, by using different robot movements, or by changing the sequence of machining paths if the machining process includes multiple paths. Object detection within the manipulation area of ​​a machining path can be accomplished by a wide variety of sensors and devices, which are either mounted on the collaborative robot or placed at suitable locations. When an object is detected within the manipulation area of ​​a machining path, a corresponding instruction signal is issued to the collaborative robot to modify or replan the machining process.This automatically prompts the collaborative robot to replan its processing if an object is located within the manipulation area of ​​a processing path. As briefly mentioned above, the modification or replanning of the processing process can be implemented in various ways. If multiple processing paths are being processed simultaneously, replanning can be achieved by changing the sequence of these paths. This allows a processing path blocked by a detected object to be processed later, in the hope that the object has been removed or moved out of the manipulation area of ​​that path in the meantime. If the detected object is located in a part of the manipulation area that can be bypassed by the collaborative robot through appropriate replanning, this represents another way to modify the processing process.For example, a multi-axis robot can process the machining path from a different direction than originally planned.

[0012] When an object is detected within the manipulation zone of a processing path, a warning signal can be issued as an instruction signal. This warning alerts personnel that an object is located within the manipulation zone of a processing path, prompting them to remove the object or take other necessary actions. The warning is preferably issued as an audible, visual, and / or tactile signal. The different types of warnings can be issued alternatively or cumulatively and are preferably issued within the processing area or along the processing paths, enabling appropriate measures to be taken to remove the detected object. Additionally or alternatively, warnings can also be issued at locations remote from the processing area, such as...a monitoring center of a processing hall, or for documentation purposes.

[0013] Depending on the instruction signal issued when an object is detected within the manipulation area of ​​a collaborative robot's machining path, workpiece processing can continue at a reduced speed along at least one machining path. This option is intended solely to prevent a potential collision between the robot and the object if other measures, such as modifying or replanning the machining process or removing the object from the manipulation area, fail. Depending on the machining process, a reduction in processing speed can negatively impact manufacturing quality.

[0014] The output instruction signal can be adapted to the type of object detected. This allows information about the type of object to be conveyed within the output instruction signal. For example, the volume of an audible warning, the brightness of a visual warning, or the intensity of a tactile warning can be adjusted to the size of an object. Provided that appropriate detection devices, such as automatic image processing systems, are available, corresponding information describing the type of object can also be output audibly or visually, so that the operator receives information about the type of object (for example, a tool lying on the processing path or a person near the processing path).

[0015] The output instruction signal can be further adapted to the position and / or orientation of the detected object. Since the position and / or orientation of the detected object influences the potential modification or replanning of the machining process, its inclusion in the output instruction signal is also of great importance. If an object is located directly on the machining path, a change to the machining process can only be achieved by temporarily altering the sequence of machining paths. In contrast, an object can be positioned near the machining path by changing the robot's angle of attack without requiring subsequent machining of that path. For example, a robot can machine the machining path from the opposite side if a person is positioned on the other side of the path.

[0016] Immediately before an imminent collision between the collaborative robot and the detected object, the workpiece processing is preferably stopped in a controlled manner. This measure prevents damage to the machine tool or its components, as well as to the workpiece itself, and facilitates the subsequent continuation of the processing process. For example, before an imminent collision between the robot and the detected object, a welding process can be terminated by adjusting appropriate welding parameters, rather than simply by abruptly switching off the welding power source. This would allow the welding of the seam to continue without significant loss of quality. This approach is also conceivable for other processing processes.

[0017] The problem according to the invention is also solved by a device mentioned above for monitoring a machining process, wherein the device for outputting an instruction signal is formed by a device for outputting an instruction signal to the collaborative robot for replanning the machining process, in that, according to the output instruction signal, the machining process is changed in the event of the detection of an object in the manipulation area around one of the predetermined machining paths of the collaborative robot by changing the sequence of the predetermined machining paths. As already mentioned, the monitoring device can be integrated into the collaborative robot or can also be located at a remote location or locations from which optimal detection of objects in the manipulation area of ​​the machining paths is possible.It is important that the object is detected proactively within the manipulation area of ​​the collaborative robot's processing path, ideally well in advance of an impending collision. Furthermore, the components of the monitoring device, such as the sensor array, detection device, and instruction signal output device, can be positioned at different, appropriately sized locations. For further information on the advantages of this monitoring device for the processing process, please refer to the description of the process monitoring method.

[0018] The device for outputting an instruction signal can also be formed by a warning device for outputting a warning.

[0019] The warning device can consist of a loudspeaker, a visual display, and / or a vibration device. Depending on the processing operation, different types of warnings and warning devices may offer advantages. For example, in very noisy processing operations, a visual or tactile warning will be more beneficial than an audible one. The warning device can be placed in appropriately suitable positions, including directly in a device worn on the operator's body, such as headphones, a wristband, a welding helmet, smart glasses, or many other similar devices.

[0020] If the detection device is wirelessly connected to the device for outputting an instruction signal, the warning can be transmitted to remote locations without disruptive wire connections.

[0021] According to a further feature of the invention, the detection device is connected to an interface for communication with the collaborative robot. The connection between the monitoring device and the collaborative robot enables modification and replanning of the machining process within certain limits, thereby ensuring the continuation of the machining process and preventing any impairment of manufacturing quality. Various standardized interfaces, such as CAN bus connections or similar, are suitable. These interfaces can be used for wired or wireless connections.

[0022] If the detection device is connected to a database containing various instruction signals depending on the type, position, and / or orientation of the detected objects, targeted instruction signals (warnings and / or command signals) can be issued to the collaborative robot. For example, suitable information can be stored in the database for various objects, such as specific tools or personnel, which is then displayed as a warning or command signal upon detection of these objects. For instance, an audible or visual warning can be issued that a pair of pliers is on the work path, prompting the operator to quickly remove them so that the processing can continue without interruption.In addition to image processing methods, other physical methods, such as those that determine the material of the object, can also be used.

[0023] The sensor setup can, for example, consist of at least one camera. This represents a suitable implementation of the sensor setup. Suitable cameras include standard cameras, high-speed cameras, and depth cameras, which can also determine the object's position in three-dimensional space. Furthermore, other sensors, such as ultrasonic transmitters and receivers, radar systems, and LiDAR (Light Detection and Ranging) systems, are also suitable.

[0024] If a device is provided for the removal of a detected object, automated removal or an attempted removal may also occur. Such devices can vary considerably depending on the processing method and the detected object, for example, from a compressed air device that can remove smaller objects using compressed air, to sliders that push the objects out of the manipulation area, to gripping systems that grasp the objects and remove them from the manipulation area.

[0025] The problem according to the invention is also solved by a processing machine, in particular a welding device, with a collaborative robot for the continuous processing of a workpiece during at least one processing period along at least one processing path, which includes a monitoring device as described above. A processing machine equipped with a monitoring device according to the invention can prevent interruptions of the processing process by automatically switching off the collaborative robot, or at least reduce its frequency, thereby increasing the cycle time for processing the workpieces and reducing rejects due to inferior quality workpieces. For further advantages, reference is made to the above description of the monitoring method and the monitoring device.

[0026] The present invention is explained in more detail with reference to the accompanying drawings. These show: Fig. 1 a schematic diagram of a processing machine for carrying out a machining process; Fig. 2 a block diagram of a monitoring device according to the invention for monitoring a machining process; Fig. 3 an embodiment of a monitoring device for monitoring a machining process; Fig. 4 a further embodiment of a monitoring device integrated in a welding robot; Fig. 5 a machining process consisting of several machining paths, during which no object was detected in the manipulation area; Fig. 6 the machining process according to Fig. 5 , wherein an object is detected in the manipulation area of ​​a processing path and a corresponding warning is issued as an instruction signal; Fig. 7 a variant of the processing process according to Fig. 6 , wherein an object was detected in the manipulation area of ​​a machining path and, according to an instruction signal, a replanning of the machining takes place; Fig. 8 shows another variant of the machining process according to Fig. 6 , wherein an object was detected in the manipulation area of ​​a machining path and the machining process is replanned according to an instruction signal; and Fig. 9 shows another variant of the machining process according to Fig. 6 , wherein an object was detected in the manipulation area of ​​a processing path and, according to an instruction signal, the processing of a processing path is continued at a reduced speed.

[0027] Fig. 1 Figure 1 shows a schematic diagram of a machining center 18 for carrying out a machining process in which a workpiece 2 is machined along at least one machining path xB using a machining tool 3 mounted on a collaborative robot 1 for at least one machining period ΔtB. In the simplest case, one machining path xB is machined for one machining period ΔtB, for example, producing a weld seam along a machining path xB. In addition to such simple machining processes, typical machining processes include the machining of several machining paths xB for several machining periods ΔtB, with breaks being inserted between the machining of the individual machining paths xB, during which the collaborative robot 1 is repositioned, tools are changed, or machining parameters are modified.The present invention relates to machining processes in which an interruption of the machining of a machining path x Bi leads to changes in the manufacturing quality and may even necessitate the discarding of the tool 3. Examples of such machining processes include welding, soldering, painting, surface treatment (e.g., using plasma jets), and many others. As mentioned above, in addition to or as an alternative to the collaborative robot 1, the workpiece 2 can also be moved using a suitable device (not shown).

[0028] Fig. 2 Figure 1 shows a block diagram of a monitoring device 10 according to the invention for monitoring a machining process. The monitoring device 10 includes a sensor device 5 for monitoring the environment of the collaborative robot 1, or at least the manipulation area around the machining path x B of the collaborative robot 1. A detection device 6 is connected to the sensor device 5, which detects objects 4 in a manipulation area around each machining path x B of the collaborative robot 1. Objects 4 can be, for example, objects on the machining path x B, objects near the machining path x B, or persons in the manipulation area. A device 7 is connected to the detection device 6, which outputs an instruction signal I if an object 4 is detected in the manipulation area of ​​a machining path x B.The instruction signal I output by device 7 can be a warning W, alerting an operator to the detection of an object 4 and prompting them to remove the object 4 within an instruction phase Δt I. Additionally or alternatively, an instruction signal A can also be output to the collaborative robot 1 as an instruction signal I for replanning the machining process. The instruction signal A can reach the collaborative robot 1 via various methods (wireless or wired), where, for example, stored alternative machining processes can be used to determine whether a change or replanning of the machining process is possible.If, within this instruction phase Δt I, it is not possible to remove object 4 from the manipulation area or to modify or replan the machining process, the usual standard safety measures of the collaborative robot 1 are triggered, typically resulting in the robot's movement stopping and thus the machining process being terminated. However, the instruction signal I, which is output by the device 7 when an object 4 is detected in the manipulation area of ​​the machining path x B, provides the possibility of taking measures to continue the machining process, or at least individual machining paths x Bi, continuously. This allows the quality of the machining process and thus of the machined workpiece 2 to be improved, and rejects to be avoided.

[0029] Fig. 3 Figure 1 shows an embodiment of a monitoring device 10 for monitoring a machining process. The monitoring device 10 includes a sensor device 5, which can, for example, be a camera 14. The sensor device 5 is connected to the detection device 6, for example, to an image processing device for processing the images captured by the camera 14. The device 7 for outputting an instruction signal I is here formed by a warning device 7' for issuing a warning W. A loudspeaker 8, an optical display 9, or a vibration device 11 can be provided as a warning device 7', which can be used optionally or cumulatively. In addition to directly connected warning devices 7', various warning devices 7' can also be wirelessly connected to the detection device 6 (not shown).The detection device 6 of the monitoring device 10 can have an interface 12 for connection with the collaborative robot 1, via which an instruction signal A from a device 7 can be output to the collaborative robot 1 (not shown) for replanning the machining process. Further interfaces (not shown) for connection with other components involved in the machining process are also conceivable.

[0030] The detection device 6 can be connected to a database 13, which contains various warnings W or instruction signals A depending on the type, position, and / or orientation of the detected objects 4. This allows the device 7 to output a different instruction signal I depending on the type, position, or orientation of the detected object 4. The database 13 can also be connected to the detection device 6 via a network 15, in particular the Internet.

[0031] Fig. 4 Figure 1 shows another embodiment of a monitoring device 10 integrated into a welding robot. In this embodiment, a welding torch is arranged on the collaborative robot 1 as a processing tool 3, or the welding device 19 is integrated into the collaborative robot 1. In the illustrated embodiment, the monitoring device 10 is located remotely from the welding device 19, but it can also be integrated into it. A warning device 7' in the form of a loudspeaker 8 is provided as part of the monitoring device 10 or externally. This loudspeaker emits a warning W when an object 4 is detected in the manipulation area of ​​the processing path x B. The warning W can, for example, also be displayed as a visual warning W on the head-up display of a welding helmet 16 to a welder S.This prompts the welder S to remove object 4 from the manipulation area of ​​the processing path x B, allowing the processing process to continue. Alternatively, a device 17 for removing a detected object 4 can be connected to the monitoring device 10, which removal device 17 automatically removes the detected object 4 from the manipulation area of ​​the collaborative robot 1. A further component of the monitoring device 10 can be a device 7" for outputting an instruction signal A to the collaborative robot 1 as a further instruction signal I. The instruction signal A can be transmitted to the collaborative robot 1 via an interface 12 of the monitoring device 10, enabling the processing process to be modified or rescheduled upon detection of an object 4.When changing the processing process, it is important that if the access of the collaborative robot 1 to the processing path x B changes, the TCP (Tool Center Point) remains the same, so that processing of the processing path x B can be guaranteed with the same quality.

[0032] Fig. 5 This diagram shows a machining process consisting of several machining paths x B1 to x B6, during which no object 4 was detected in the manipulation area. Workpiece 2 has six machining paths x B1 to x B6, which are machined sequentially. Accordingly, machining B begins at time t 0 with the machining of the first machining path x B1, which is carried out at a machining speed v B for the machining duration Δt Bi until time t 1. After a pause, machining of machining path x B2 begins at time t 2 and is completed at time t 3. The machining process is completed after machining path x B6 is finished at time t 11. Since no object 4 is located in the manipulation area of ​​any machining path x B1 to x B6, no instruction signal I in the form of a warning W or a command signal A is issued during the machining duration.

[0033] Fig. 6 shows the processing process according to Fig. 5 , in which an object 4 is detected in the manipulation area of ​​a processing path, here processing path x B3. Processing B begins with processing of processing path x B1 and continues with processing of processing path x B2. Just before processing of processing path x B3, the detection device 6 detects an object 4 in a processing path, here in processing path x B3, and issues a warning W as an instruction signal I in a timely manner. The warning W begins at time t WA and continues until the object 4 is removed. In the illustrated embodiment, the warning W ends at time t WE, whereupon the processing process continues with processing of processing path x B3 and proceeds as planned, as in the case of processing according to Fig. 5 , can be ended.

[0034] Fig. 7 shows a variant of the processing process according to Fig. 6 In this embodiment, an object 4 is detected in the manipulation area of ​​processing path x B3, and a replanning of the processing process takes place according to instruction signal I, as indicated by instruction signal A. In this embodiment, the replanning of the processing occurs by changing the sequence of the processing paths x Bi. In the illustrated embodiment, after processing path x B2 is completed at time t 4, processing of processing path x B4 continues, followed by processing of processing path x B5 and then processing of processing path x B6. During the processing of processing path x B6, the detected object 4 is removed from the manipulation area at time t IE, thereby stopping the output of instruction signal I or instruction signal A. The processing is then completed with processing path x B3 in the modified sequence.As long as object 4 is detected in the manipulation area, the instruction signal I or instruction signal A is output (between times t IA and t IE ).

[0035] Fig. 8 Figure 1 shows another variant of a machining process, in which an object 4 was detected in the manipulation area of ​​the machining path x B3 and, according to an instruction signal A to the collaborative robot 1, a replanning of the machining process takes place. In contrast to the embodiment according to Figure 2, the following applies: Fig. 7 Here, the replanning of the processing process does not occur by changing the sequence of the processing paths x B1, but rather by extending the pause between the processing of processing path x B2 and processing of processing path x B3, until object 4 has been successfully removed from processing path x B3 or its manipulation area. In the illustrated embodiment, object 4 is detected in the manipulation area between times t IA and t IE. At time t IE, object 4 is removed from processing path x B3, thus ending the output of an instruction signal I or instruction signal A. Processing of processing path x B3 can then resume at time t 4, and the processing can be completed as planned until processing path x B6 is processed.Although this variant increases the overall processing time, there is no interruption of the processing of the individual processing paths x Bi during the processing periods Δt Bi, thus the quality of the processing is not negatively affected.

[0036] In Fig. 9 is another variant of the processing process according to Fig. 6 The diagram shows that an object 4 was detected in the manipulation area of ​​the processing path x B3, and, according to an instruction signal A, the processing of a processing path is continued at a reduced speed. Here, after the detection of an object 4, the currently running processing, in this case the processing of processing path x B2, is completed, and then the processing of processing path x B3, in whose area the object 4 was detected, is carried out at a reduced speed v B' compared to the normal processing speed v B. This extends the processing time Δt B3 of the processing path x B3, thus creating more time to remove the object 4 from the processing path x B3 or to change the movement of the collaborative robot 1.If object 4 is no longer recognized at time t IE, the machining of workpiece 2 can be completed by machining the machining path x B3 at normal machining speed v B and continued with the machining of the further machining paths x B4 and x B5, and finally completed with the machining of machining path x B6. In this variant of the machining process, the total machining time is also reduced compared to the variant according to... Fig. 5 increased, yet ensures that the processing of the individual processing paths x Bi can be carried out continuously without interruption during the processing periods Δt Bi.

[0037] The present invention ensures the execution of a machining process with uninterrupted machining of the machining path(s) without impairing the quality of the machined workpiece 2.

Claims

1. A method for monitoring a working process, in which a workpiece (2) is worked continuously along each of at least one predetermined working path (xBi) on the workpiece (2) during at least one working time period (ΔtBi) by means of a working tool (3) arranged on a collaborative robot (1), wherein the environment of the collaborative robot (1) is monitored and an object (4) in a manipulation region of the collaborative robot (1) around one of the predetermined working paths (xBi) on the workpiece (2) is detected, characterized in that in the event that an object (4) is detected in the manipulation region of the collaborative robot (1) around one of the predetermined working paths (xBi) on the workpiece (2) within an instruction phase (ΔtI) an instruction signal (I) is emitted and the working process is continued along one of the predetermined working paths (xBi) on the workpiece (2) without interruption, characterized in, that as instruction signal (I) a command signal (A) to the collaborative robot (1) for the re-planning of the working process is emitted, and in accordance with the emitted command signal (A), in the event that an object (4) is detected in the manipulation region around one of the predetermined working paths (xBi) of the collaborative robot (1), the working process is changed by the sequence of the predetermined working paths (xBi) being altered.

2. The method according to Claim 1, characterized in that an alarm (W), preferably in the form of an acoustic, visual and / or tactile alarm (W), is emitted as instruction signal (I).

3. The method according to Claim 1 or 2, characterized in that in accordance with the emitted command signal (A) in the event of the detection of an object (4) in the manipulation region around one of the predetermined working paths (xBi) of the collaborative robot (1), the working of the workpiece (2) is continued at reduced working speed (vB') along at least one of the predetermined working paths (xBi) .

4. The method according to one of Claims 1 to 3, characterized in that the emitted instruction signal (I) is adapted to the type and / or the position and / or location of the detected object (4).

5. The method according to one of Claims 1 to 4, characterized in that immediately before an imminent collision of the collaborative robot (1) with the detected object (4), the working of the workpiece (2) is stopped in a controlled manner.

6. A device (10) for monitoring a working process, in which a workpiece (2) can be worked continuously along each of at least one predetermined working path (xBi) on the workpiece (2) during at least one working time period (ΔtBi) by means of working tool (3) arranged on a collaborative robot (1), said device comprising a sensor apparatus (5) for monitoring the environment of the collaborative robot (1) and a detection device (6) for detecting an object (4) in a manipulation region of the collaborative robot (1) around one of the predetermined working paths (xBi) on the workpiece (2), characterized in that the detection device (6) is connected to a device (7) for emitting an instruction signal (I) within an instruction phase (ΔtI) in the event that an object (4) is detected in the manipulation region of the collaborative robot (1) around one of the predetermined working paths (xBi) on the workpiece (2), so that the working process can be continued along one of the predetermined working paths (xBi) on the workpiece (2) without interruption, characterized in that the device (7) for emitting an instruction signal (I) is formed by a device (7") for emitting a command signal (A) to the collaborative robot (1) for the re-planning of the working process, in that in accordance with the emitted command signal (A), in the event that an object (4) is detected in the manipulation region around one of the predetermined working paths (xBi) of the collaborative robot (1), the working process is changed by the sequence of the predetermined working paths (xBi) being altered.

7. The device (10) according to Claim 6, characterized in that the device (7) is formed for emitting an instruction signal (I) by an alarm device (7') for emitting an alarm (W).

8. The device (10) according to Claim 7, characterized in that the alarm device (7') is formed by a loudspeaker (8), a visual display (9) and / or a vibration device (11).

9. The device (10) according to one of Claims 6 to 8, characterized in that the detection device (6) is connected wirelessly to the device (7) for emitting an instruction signal (I) .

10. The device (10) according to one of Claims 6 to 9, characterized in that the detection device (6) is connected to an interface (12) for connection to the collaborative robot (1).

11. The device (10) according to one of Claims 8 to 13, characterized in that the detection device (6) is connected to a database (13), which database (13) comprises various instruction signals (I) as a function of the type and / or the position and / or the location of the detected objects (4).

12. A working machine (18), in particular a welding device (19), comprising a collaborative robot (1), for the continuous working of a workpiece (2) during at least one working time period (ΔtB) along at least one predetermined working path (xB), characterized in that a monitoring device (10) according to one of Claims 6 to 11 is provided.