CN109794967B

CN109794967B - Method and device for protecting the working area of a robot during a use phase

Info

Publication number: CN109794967B
Application number: CN201811383805.3A
Authority: CN
Inventors: M.莫尔
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2017-11-17
Filing date: 2018-11-15
Publication date: 2022-05-27
Anticipated expiration: 2038-11-15
Also published as: CN109794967A; DE102018214439A1

Abstract

The invention relates to a method for protecting a working area of a robot during a use phase and to a device for carrying out the method. The working area of 360 ° around the robot is divided into planar units and the locally fixedly mounted scanning device is calibrated in a coordinate system. The working area is completely scanned after the scanning device is aligned. The robot divides the plane elements into at least two differently weighted plane elements and unweighted plane elements according to its movement. This is done dynamically and continuously before and during the use phase. The weighted plane elements represent the protection ranges. After transmitting the information about the protective range to the scanning device, it is possible to monitor the working area, wherein undesired events in the protective range can be recorded. Information about it is sent to the robot or a reliable control device. Depending on where the undesired event has occurred, a corresponding specific event is triggered at the robot, wherein the plane elements are subdivided immediately after the robot reaction.

Description

Method and device for protecting the working area of a robot during a use phase

Technical Field

The invention relates to a method for protecting a working area of a robot during a use phase. In particular, the invention relates to a method and an apparatus for carrying out the method according to the invention.

Background

Robots are used in industrial automation and semi-automation manufacturing. In this case, also fields of application are known, in which humans and machines work together in a defined area. For example, hybrid assembly work stations are known. The division of tasks between human and machine results in the robot and human passing through a localized area in a tight space. In order to protect mankind and for a smooth completion of the working process, different solutions and technical achievements have been proposed in recent years in the technical field of fennerless manufacturing and human-machine cooperation.

In order to prevent a general collision, camera-based monitoring of a mobile machine and/or of a mobile machine element is proposed, for example, in DE 102006048163. In this case, the area of the machine is monitored by means of a camera by comparing the captured image data with a database created in advance. Furthermore, a current position of the machine is determined based on the correlation of the currently acquired image data with the database and a future position reached within the stopping time is estimated. From this estimate, a monitor can then be generated based on the estimate. The size of the safety zone is determined from the estimate.

In this process, it is considered disadvantageous that a comprehensive database must first be generated, in which it is not guaranteed that all possible situations around the use of the collection machine are present. Finally, the method is based only on estimates that are also likely to be inaccurate.

Document DE 102006057605 discloses a method and a device for monitoring a three-dimensional space, in which a sensor unit is used. The sensor unit comprises two cameras capable of taking two independent images of the space surrounding the machine. The images are compared to each other to identify image regions in the images that are disjoint with respect to each other. In this case, the alarm signal is generated when the disjoint image areas cover the previously determined virtual protection area. The machine can then be shut down if necessary based on the signal. Advantageously, the protection area virtually generated by the sensor unit may be three-dimensional. It would be considered disadvantageous that very subdivided divisions are not realized here.

DE 102007006708 proposes a method for protecting a robot device, in which the current direction of movement of the device is compared with the direction of a reference vector and safety-relevant functions are triggered when deviations occur in a defined region.

Document DE 102010017857 shows a 3D security device and a method for protecting and operating at least one machine. Here, three-dimensional image data is first acquired from a work station. Furthermore, the movement pattern of the operator at the work station is determined and a protection command is issued to the machine upon recognition of the danger of the operator. There is no explicit provision for differential treatment of the various zones of the job site.

DE 202009012589 proposes a photosensor. The sensor can acquire a planar or three-dimensional shaped protection area. Here, the received light is received from the protected area, and then the emitted light is emitted into the protected area where the object is located by means of the light emitter.

According to the prior art, the size of the protection area must usually be calculated as "worst case". In addition to this, for example, the maximum possible speed of the robot and the very probable danger location for humans are taken into account. A general disadvantage of the solutions according to the prior art is that only static or fixed protection and warning ranges exist, which are activated or deactivated by the robot or the SPS. The protection range is therefore always kept large or a switch to a smaller protection range is necessary. For this reason, a plurality of scanners, cameras or sensor units is usually required, since the protective range of each scanner is limited, for example. Thus, although the robot is not in a hazardous area, a loss of clock time may result in the area being violated. There is no fine division in the dynamically weighted protection range.

Disclosure of Invention

The object of the present invention is therefore to provide a method and a device which allow dynamic processes in the protection of robots to be taken into account in an efficient manner.

In a preferred embodiment of the invention, a method for protecting a working area of a robot during a use phase is provided, comprising the following steps. The 360 ° working area around the robot is divided into planar units which are part of the coordinate system of the robot. The locally fixedly mounted scanning device is calibrated in the coordinate system of the robot. The scanning device is aligned such that the working area can be completely scanned, wherein the method comprises the further steps of. The plane elements are divided by the robot into at least two plane elements with different weights and into plane elements without weights according to the movement process and the speed of the robot, wherein the weights are dynamically and continuously applied before and during the use phase, and the weighted plane elements represent the protection range. Information about the protection range is provided to the scanning device. The scanning device is used to monitor the working area for the occurrence of an undesired event in the protective range. Information about the protective range in which the undesired event has occurred is transmitted from the scanning device to a reliable control device or robot. The control device or the robot distinguishes in which of the at least two differently weighted planar units an undesired event has occurred. Depending on the distinction, a specific event is triggered by the control device or the robot at the robot, and the individual surface elements are subdivided by the robot depending on the specific event triggered at the robot.

In this way, a finer resolution of the 360 ° safety space around the robot can be achieved in an efficient manner, wherein at the same time a flexible and dynamic protection range is achieved. This eliminates the need for a separate static protective range, but creates and permanently analyzes its own protective range from a large number of planar elements. The scanner need not create a dynamic range of protection, but merely report the violation of a planar element. In particular, by the repartitioning in the last step, a basis for a very dynamic system is obtained. That is, once the new partitioning of the planar elements is performed, the information is reanalyzed and may have dynamically caused additional specific events at the robot.

Other preferred implementations of the invention derive from the remaining features of the invention.

In the implementation of the invention, it is therefore provided that the event which is dependent on the specific trigger at the robot being differentiated can be the stopping of the robot, or can be a matching of the speed of the robot to the MRK speed, or can be a reduction in the speed of the robot. Thus, it can be reported how close a planar unit is to the robot to be violated to trigger a corresponding specific event. Thus, for example, a planar unit can be provided which is only responsible for the speed reduction of the robot. In contrast, other planar elements are associated with triggering a robot stop or MRK speed when reporting an infringement. The appropriate event is triggered accordingly as a function of the weighting, wherein after the interference has been eliminated, a non-interfering robot operation can be achieved on the basis of an immediate re-analysis of the planar unit. In this way, the particularly fine division ensures that the loss of clock time is not necessarily undertaken each time a region is violated, and nevertheless ensures proper protection of the work region.

In a further preferred embodiment of the invention, it is provided that the at least two differently weighted plane elements each represent a first protective range area and a second protective range area, wherein the first protective range area is in the immediate vicinity of the robot and the second protective range area at least partially adjoins the outside of the first area. Thus, in general, it is possible to determine in the robot or in the controller which specific event is associated with which protection range area. A particularly fast and dynamic analysis of the planar unit can thus be achieved on this plane, which is particularly advantageous for fast robot operation.

In a further preferred embodiment of the invention, it is provided that the undesired event is the movement of a person into the working area of the robot. Such undesirable events are present in the manufacture of unguarded fences, particularly in the human-machine cooperation. This can be an estimated, i.e. deliberately caused violation of the protected space, or an unintentional violation, e.g. during a fault. In the case of deliberate action, it is conceivable, for example, for humans to provide material in an external safety area, as a result of which the robot briefly reduces its speed. Once the human leaves the planar cell, the robot's previous work program can continue seamlessly and without clock time loss based on the dynamic repartitioning of the planar cell.

In a further preferred embodiment of the invention, it is provided that the planar units are designed, for example, in the form of squares and have a minimum dimension of 100 × 100mm, preferably 200 × 200mm, more preferably 300 × 300 mm. Thereby ensuring a particularly fine division. Thus, depending on the course of the movement of the robot, it can be determined in a very subtle manner, for example whether it is really necessary to stop the robot or whether it may be sufficient to analyze the reduction in speed.

Alternatively, the planar elements may have any other shape, such as rectangular, diamond, trapezoidal, parallelogram, etc. Combinations of planar elements having different sizes and/or different shapes are also possible.

According to a further embodiment of the invention, the minimum size of a protective range and, if necessary, of the planar unit is increased as a function of the movement process, position and direction of travel of the robot. In this way, personalization can be achieved according to the working use of the robot. For any conceivable course of motion, a separate suitable safety range can be determined which is constantly dynamically adjusted during operation.

In addition, in a further embodiment of the invention, it is provided that the minimum size of the plurality of protective ranges is increased depending on the movement process, position and travel direction of the robot. This makes it possible to realize individual adjustment of the guard space during dynamic weighting.

In a further preferred embodiment of the invention, provision is made for the robot to carry out a subdivision of the individual planar units as a function of the particular event triggered at the robot and as a function of the distance from the planar unit in which the undesired event occurred to the robot. In this way, individual adjustment of the protective space can also be achieved in a better manner.

Furthermore, in a further preferred embodiment of the invention, it is provided that the scanning device comprises at least one scanning element, wherein the at least one scanning element is placed directly on the robot and, if necessary, in particular if shadows formed by equipment parts or other interference influences block the at least one scanning element on the robot, at least one further scanning element is placed outside the robot. In this way, it is ensured that the entire required working area is scanned completely. The final number of scanning elements can thus be determined depending on the application. Thus, the scanning element placed on the robot may already be considered sufficient to provide the desired effect. Also, two scanning elements may be provided on the robot. If this is considered insufficient, for example when the at least one scanning element on the robot is obscured by shadows formed by equipment components or other disturbing influences, at least one further scanning element may be placed outside the robot. In other words, the scanning device may comprise only scanning elements arranged on the robot. Furthermore, in another implementation, the scanning device may further comprise a scanning element on the robot and at least one further scanning element external to the robot. Depending on how detailed the existing application area of the robot has to be acquired in order to ensure safe production management, the final number of scanning elements can be specified. The position or location or place outside the robot where the at least one further scanning element of the scanning device is arranged is not particularly limited. Thus, the position may be directly on the outer edge of the entire protection range or even inside the outer area of the protection range at the same height as the robot. Furthermore, it is also conceivable to position at least one further scanning element in this area on the ceiling or on a structure located above the working area, for example a beam or other building. Above all, the scanning device scans the entire required working area completely by means of one scanning element or, if necessary, a plurality of scanning elements, so that the method described in the present invention can be implemented accordingly.

In particular, a person entering the protected area hides one of the scanning elements. In this case, it is important that there is sufficient scanner for the respective application, for example on the robot base. The final number of scanning elements depends on the respective application or the environment to be protected. Depending on the application, a scanning element is also required which scans in the direction of the robot. In particular, if the scanning elements form shadows due to, for example, being mounted on the robot base by means of equipment or hall posts or the like, these scanning elements are necessary. In other words, the number of scanning elements is determined by the local conditions and the application. The premise is that: the entire coverage of the secure area is not affected by the shadows formed by the equipment components.

In a further embodiment of the invention, it is provided that the method according to the invention comprises a robot, a scanning device and a control unit, and the device protects the working area of the robot during the use phase. The device can thus be individually adapted according to the desired implementation and set up for the method to ensure an effective and dynamic protection of the robot.

The different embodiments of the invention mentioned in the present application can advantageously be combined with one another, unless otherwise stated in individual cases.

Drawings

The invention is elucidated in the following in an embodiment in accordance with the relevant figures. In the drawings:

fig. 1 shows an arrangement for protecting a working area of a robot;

fig. 2 shows a device for protecting the working area of a robot during an infringement;

fig. 3 shows a device for protecting the working area of a robot during an infringement.

Detailed Description

Fig. 1 shows an apparatus 10 for protecting a work area of a robot 12, which apparatus 10 is adapted to perform the method according to the invention. Here, a working area is determined around 360 ° of the robot 12. The movement process of the robot 12 can thus take place in the entire working area, in which the robot 12 is rotated, for example, about its axis of rotation through all angular ranges, or in which, for example, the boom of the robot 12 moves back and forth. A combination of the two procedures is also possible. Finally, all the movement processes that may occur at the robot 12 during the operating phase are conceivable. In fig. 1, the robot 12 is fixed in a central point. However, the following working spaces are also conceivable: in which the robot 12 itself places the central point in a certain frame. In addition to the robot 12, a scanning device 14 can also be seen. The scanning device 14 here comprises different scanning elements, two of which are placed directly on the robot 12 and one on the outside. Here, the robot 12 is located, for example, in the center of a coordinate system 16, and the coordinate system 16 is divided into individual plane units 18, which are arranged, for example, in a square shape, so as to present the appearance of a checkered pattern. Here, the checkered pattern size depends on the size of the planar unit 18, which planar unit 18 can have a minimum size of, for example, 200 × 200 mm. It is also conceivable that the minimum dimension of 200 x 200mm simultaneously represents the maximum dimension of the planar unit 18. Here, the coordinate system 16 represents the system of the robot 12 and the system of the scanning device 14. This is the case in particular after calibration of the respective systems of the robot 12 and the scanning device 14. This calibration may also be understood as comparing the position of the scanning device 14 and the robot 12 in the coordinate system 16. The scanning device 14 may also be a sensor, for example. The scanning device 14 is adapted to scan the entire working area of the robot 12. The electronic sampling can be carried out in various ways and is not necessarily specified only by technical specifications. The scanning device 14 can cover the working area, for example, with protective rays or the like from different locations and thus ensure a reliable output of raw data with X/Y coordinates in planar units. Furthermore, fig. 1 shows a protective range area 22 and a protective range area 20 in the immediate vicinity of the robot 12, the protective range area 20 surrounding the protective range area 22 on the outside. The two

protective range regions

20, 22 are formed by a plurality of planar elements 18. Outside the

protective area

20, 22, a person 24 is visible, which is located in a marked planar unit 26. Although the scanning device 14 acquires the person 24. However, the lack of weighting in the planar unit 18 does not result in a reaction of the robot 12.

Fig. 2 shows an apparatus 10 for protecting the working area of a robot 12 during an infringement. A person 24 can be seen, who enters the first protective zone 20 and thus indirectly triggers a specific event at the robot 12. The marked planar element 26 is registered by the scanning device 14 as violating the planar element 18. This information is transmitted to the robot 12 or a control device, not shown, where further division is performed. In the example shown in fig. 2, this is an infringement of a planar element 18 with a velocity reduction weighting. Thus, the speed reduction has been a specific event associated with the violation.

Fig. 3 shows an arrangement 10 for protecting the working area of a robot 12 during an infringement. A person 24 can also be seen, who enters the second protective range area 22. Otherwise, fig. 3 is the same as fig. 2. The marked planar unit 26 is now in close proximity to the robot 12. The scanning device 14 transmits the violation to the robot 12 or to a control device not shown, where further partitioning is performed there. In the example shown in fig. 3, this is an infringement of a plane element 18 with a stop or MRK mode weighting.

List of reference numerals

10 device

12 robot

14 scanning device

16 coordinate system

18 plane unit

20 first protective zone

22 second protective range region

24 persons

26 plane element

Claims

1. A method for protecting a working area of a robot (12) during a use phase, comprising the steps of:

-dividing a 360 ° work area around the robot (12) into planar units (18), the planar units (18) being part of a coordinate system (16) of the robot (12);

-calibrating the coordinate system (16) of the locally fixedly mounted scanning device with the coordinate system (16) of the robot (12);

-aligning the scanning device (14) so as to be able to scan the work area completely;

characterized in that the method comprises the further steps of:

dividing the planar unit (18) by the robot (12) into at least two differently weighted planar units (18) and into unweighted planar units (18) depending on the course of its movement and its speed, wherein the weighting is carried out dynamically and continuously before and during the use phase and the weighted planar units (18) represent the protection range;

-providing information about the protection range to the scanning device (14);

monitoring, by means of the scanning device (14), whether an undesired event has occurred in the working area within the protective range;

-transmitting information about the protection area in which the undesired event occurred from the scanning device (14) to a reliable control device or robot (12);

distinguishing, by the control device or the robot (12), in which of the at least two differently weighted planar units (18) an undesired event has occurred;

-triggering a specific event at the robot (12) by means of the control device or the robot (12) depending on the differentiation, and subdividing the individual plane elements (18) by the robot (12) depending on the specific event triggered at the robot (12).

2. The method according to claim 1, characterized in that the event that is triggered specifically at the robot (12) upon distinguishing can be a stop of the robot (12), or can be a matching of the speed of the robot (12) to the MRK speed, or can be a reduction of the speed of the robot (12).

3. The method according to claim 1, characterized in that the at least two differently weighted plane elements (18) represent a first protection range area (20) and a second protection range area (22), respectively, wherein the first protection range area (20) is in close proximity to the robot (12) and the second protection range area (22) at least partially adjoins outside the first protection range area (20).

4. A method according to any of claims 1-3, characterized in that the undesired event is a person (24) moving into the working area of the robot (12).

5. A method according to any one of claims 1 to 3, characterized in that the planar unit (18) has a minimum size of 100 x 100 mm.

6. A method according to any one of claims 1 to 3, characterized in that the planar unit (18) has a minimum dimension of 200 x 200 mm.

7. A method according to any one of claims 1 to 3, characterized in that the planar unit (18) has a minimum dimension of 300 x 300 mm.

8. A method according to any one of claims 1-3, characterized in that the minimum size of a protective range is increased depending on the course of movement, position and direction of travel of the robot (12).

9. A method according to any one of claims 1 to 3, characterized by increasing the minimum size of the plurality of protection ranges (20, 22) in dependence on the course of movement, position and direction of travel of the robot (12).

10. A method according to any one of claims 1 to 3, characterized in that the individual plane elements (18) are subdivided by the robot (12) in dependence on the specific event triggered at the robot (12) and in dependence on the distance of the plane element (18) from the robot (12) in which the undesired event occurs.

11. Method according to any of claims 1 to 3, characterized in that the scanning device (14) comprises at least one scanning element, wherein at least one scanning element is placed directly on the robot (12) and at least one further scanning element is placed outside the robot (12) when necessary, in particular when a shadow formed by a piece of equipment or other disturbing influences obscures at least one scanning element on the robot.

12. Device (10) for protecting a working area of a robot (12) during a use phase according to the method of claims 1 to 11, comprising the robot (12), a scanning device (14) and a control unit.