METHOD FOR OPERATING A ROBOT ASSEMBLY AND ROBOT ASSEMBLY

Description

[0001] The invention relates to a method for operating a robot assembly, wherein a plurality of distance sensor units are arranged on a surface of the robot assembly for collision protection of the robot assembly.

[0002] Furthermore, the invention is directed to a robot assembly. The robot assembly comprises a manipulator unit and / or an effector unit, a plurality of distance sensor units for collision protection of the robot assembly, and a control unit. The distance sensor units are arranged on a surface of the manipulator unit and / or on a surface of the effector unit.

[0003] In this context, the manipulator unit is understood to be a programmable device with one end that can be positioned essentially freely in space. For example, the manipulator unit is designed as a robot arm. The effector unit is understood to be an assembly designed to interact with a workpiece to be machined and / or handled. For example, the effector unit can be designed as a gripper unit or a tool unit.

[0004] Collision protection that uses distance sensor units arranged on the robot assembly is also called robot-centric protection.

[0005] Such robot assemblies and methods for their operation are known from the prior art. Robot assemblies with a plurality of distance sensor units for collision protection are used, particularly when the robot assemblies share their workspace with humans. This is known under the term human-robot cooperation AS:TOP. In such cases, the distance sensor units ensure that the humans present within the workspace of the robot assembly remain unharmed. Furthermore, collisions between the robot assembly and its components and other non-human objects in the workspace must be avoided. Based on the distances measured by the distance sensor units, a movement of the robot assembly can be slowed down, changed in direction, stopped, or prevented entirely.The working speed of the robot assembly depends on the detection range of the distance sensor units. The robot assembly may only move at a speed that allows it to come to a stop or decelerate to a desired speed before coming into contact with a detected person or object. US 2019 / 143522 A1 discloses a robot. Furthermore, US 8 504 203 B2 discloses a manipulator and a method for controlling the same. US 2018 / 229379 A1 describes a contact detection device, a control device, a contact detection system, a contact detection method, and a contact detection program.

[0006] In contrast, the working speed of robot assemblies that do not share their workspace with humans is limited only by the process to be performed and / or the performance of the robot assembly's drives. In some applications, such robot assemblies can therefore achieve higher working speeds and thus greater work efficiency than is possible with robot assemblies operated in a human-robot collaboration.

[0007] The objective of the invention is therefore to further increase the efficiency of robot assemblies operated within the framework of human-robot cooperation. Naturally, this should be done while maintaining known safety standards.

[0008] The object is achieved by a method for operating a robot assembly of the type mentioned above, comprising the following steps: Providing a switch-off space which is defined within a working space of the robot assembly in a fixed location or depending on a pose of the robot assembly, wherein the switch-off space is a section of the working space of the robot assembly in which an undesired collision of the robot assembly or its components with a human and / or other objects can be excluded, operating those distance sensor units which are located outside the switch-off space for collision protection of the robot assembly, and deactivating those distance sensor units which are located within the switch-off space.

[0009] The shutdown chamber can therefore also be referred to as a collision exclusion chamber. Thus, the operating speed of those sections of the robot assembly located within the shutdown chamber is limited only by the requirements of the process being performed and by the performance of the robot assembly's drives. Robot-centric collision protection is not required within the shutdown chamber. The check to determine whether a distance sensor unit is located inside or outside the shutdown chamber is performed individually, i.e., for each of the distance sensor units. In this context, the plurality of distance sensor units comprises at least two distance sensor units. Thus, the overall operating speed of the robot assembly can be increased while maintaining the known, high safety standards. The robot assembly can thus be operated with high operating efficiency.This is especially true considering that different sections of the robot assembly often move at different speeds. In many applications, sections of the robot assembly located close to an effector move faster than sections of the robot assembly located close to a robot base. The efficiency gain is therefore particularly significant when those sections of the robot assembly operating at comparatively high speeds are located in the shutdown area. Disabling individual distance sensor units also promotes energy efficiency. Furthermore, an efficiency gain is realized with regard to the processing of sensor data.

[0010] The shutdown room is a three-dimensional space.

[0011] Disabling distance sensor units can be achieved, for example, by switching them off or deactivating them. It is also possible to simply ignore the detection results of the distance sensor units that are to be disabled in a control unit of the robot assembly.

[0012] A fixed, defined cut-off space can be a section of the workspace that is inaccessible to collision objects due to at least one surrounding object or at least one safety device. In other words, the surrounding object or the safety device prevents a collision object, which in this case also includes a human, from entering the cut-off space. The robot assembly itself can also cause the inaccessibility. This can be because the spaces between the robot assembly and surrounding objects and safety devices can be shaped in such a way that a collision object cannot enter the cut-off space. It is also possible that the spaces between the robot assembly and surrounding objects and safety devices are simply too small for a collision object.In this context, environmental objects include walls, ceilings, columns, or other objects present in the vicinity of the robot assembly. Safety devices can be implemented as fences, gratings, and / or light barriers, for example. This reliably prevents collisions between the robot assembly and a collision object in the shutdown area, allowing the robot assembly to operate at increased speed in the shutdown area.

[0013] Furthermore, a shutdown space defined depending on a pose of the robot assembly can be a section of the workspace that is inaccessible to collision objects due to a spatial arrangement of components of the robot assembly that forms the pose. In this case, the components of the robot assembly are positioned in space such that a collision object cannot penetrate the shutdown space, either due to its size or shape. Again, a collision object also includes a human. Thus, in this case, too, it can be reliably ruled out that a collision will occur in the shutdown space. Consequently, those sections of the robot assembly located in the shutdown space can operate at high speed.

[0014] In one variant, the shutdown area is taught. In other words, the shutdown area is taught. The robot assembly specifically moves to boundary points or interfaces of the shutdown area. A corresponding position is then saved and linked to a location definition of the shutdown area. The shutdown area is therefore stored on a control unit of the robot assembly. In this way, a shutdown area can be easily and reliably provided. In one example, a shutdown area is located inside a container from which the robot assembly removes objects. In such a case, points on the container edge, for example, are taught as boundary points of the shutdown area.

[0015] In one embodiment, each of the distance sensor units is deactivated upon entering the shutdown area. This ensures that distance sensor units located within the shutdown area are deactivated. These distance sensor units are therefore not used for collision protection, allowing at least those sections of the robot assembly located within the shutdown area to operate at high operating speeds.

[0016] In addition, each of the distance sensor units can start operating when the robot assembly exits the shutdown area to provide collision protection. As soon as a distance sensor unit leaves the shutdown area, it is reused for collision protection. Consequently, the robot assembly, or more precisely those sections of the robot assembly located outside the shutdown area, are reliably protected against collisions.

[0017] In an alternative, each distance sensor unit is periodically checked to determine whether it is located inside or outside the shutdown compartment. In this context, its position within the robot assembly is assumed to be known for each distance sensor unit. Such information can be stored on a control unit of the robot assembly. Furthermore, it is assumed that information about the current position of movable joints within the robot assembly is available via corresponding sensors. Corresponding sensor values ​​can be communicated to a control unit of the robot assembly. In this way, it can be reliably determined for each distance sensor unit whether it is located inside or outside the shutdown compartment. Periodic checking is efficient in terms of computing capacity and energy consumption. An assigned checking frequency can also be set depending on the situation.

[0018] Alternatively or additionally, a detection radius of a distance sensor unit positioned adjacent to a shutdown area can be set to a distance of the distance sensor unit from the shutdown area. This means that a distance of the distance sensor unit from the shutdown area corresponds to the detection radius of the distance sensor unit. Using the detection radius, a spherical segment-shaped detection area is spanned around the distance sensor unit. This ensures that the distance sensor unit is only used for collision protection outside the shutdown area. In other words, objects within the shutdown area cannot be detected. Setting the detection radius in this way means that it is successively reduced when a section of the robot assembly carrying the distance sensor units approaches a shutdown area.Similarly, the detection radius can be increased if a section of the robot assembly on which the distance sensor unit is mounted moves away from the cut-off area. This ensures reliable collision monitoring up to a boundary surface of the cut-off area.

[0019] Alternatively, the detection radius of a distance sensor unit positioned adjacent to a shutdown room can be set smaller than the distance between the distance sensor unit and the shutdown room. For example, the detection radius can be set to a percentage less than 100% of the distance, for example 95% or 98%. In this case, it is deliberately accepted that a detection gap will arise between a boundary surface of the shutdown room and a detection area of ​​the distance sensor unit spanned by the detection radius. However, the detection radius is set such that the detection gap is always smaller than a specified maximum gap, i.e. a gap with a specified maximum size. This ensures that all potential collision objects are detected despite the detection gap.At the same time, this alternative ensures that elements or objects that physically delimit the shutdown area are reliably not detected as collision objects. This allows the robot assembly to operate efficiently.

[0020] In one embodiment, the detection radii of distance sensor units arranged adjacently on the surface of the robot assembly, which span adjacent or overlapping detection areas, are coordinated such that detection gaps between the detection areas do not exceed a maximum size. This ensures that no unwanted detection gaps arise in situations where a detection radius of a distance sensor unit is changed as explained above. The robot assembly is thus always reliably protected against unwanted collisions.

[0021] Additionally, the object is achieved by a robot assembly of the type mentioned above, in which the control unit comprises means for carrying out the method according to the invention. Such a robot assembly can therefore be operated at comparatively high operating speeds while maintaining the usual high safety standards with regard to unwanted collisions. In other words, such a robot assembly can be operated efficiently and simultaneously safely. It is understood that the control unit can comprise means for deactivating individual distance sensor units, keeping them deactivated, and switching them back on. As already mentioned, a distance sensor unit can be deactivated either by switching it off or deactivating it. For this purpose, a power supply to the distance sensor units can be selectively interrupted.It is also possible to simply ignore a detection result from the distance sensor units depending on the situation.

[0022] The distance sensor units can operate according to a time-of-flight method. In this context, a sensor operating according to a time-of-flight method comprises a transmitter unit and a receiver unit. As already mentioned, the distance sensor units are coupled to the control unit, which includes an evaluation unit. The evaluation unit determines a sensor signal in the form of a distance value based on the propagation time required for a signal emitted by the transmitter unit to be detected by the receiver unit and on knowledge of the wave propagation speed in the relevant space. Time-of-flight sensors therefore operate comparatively quickly and precisely. This makes them particularly well-suited for use in the context of robot assemblies.

[0023] In addition, the detection radius for each distance sensor unit can be changed during operation. As already explained, each detection radius defines a detection area. This can therefore be adapted to the situation. This ensures, on the one hand, that the robot assembly is reliably protected against collisions outside the shutdown area, and, on the other hand, that no detection occurs inside the shutdown area.

[0024] In one variant, each of the distance sensor units comprises at least two distance sensors. The detection range of one of the distance sensors and the detection range of the other distance sensor overlap at least partially. The detection ranges can also be essentially identical, or one of the detection ranges can completely encompass the other detection range. This results in particularly reliable protection against unwanted collisions.

[0025] It is possible for the distance sensors in a distance sensor unit to use different sensor principles. In particular, one of the distance sensors uses an electromagnetic, preferably optical, sensor principle, while another uses an acoustic sensor principle. The acoustic sensor principle is based primarily on ultrasound. Since different sensor principles have different advantages and disadvantages, a combination of two distance sensors with different sensor principles combines the advantages, resulting in particularly reliable collision protection. For example, this makes it possible to detect people wearing any clothing and objects made of any material under different environmental conditions (brightness, fog, humidity, etc.).This is especially true when compared to capacitive sensors, which are less reliable, especially when humidity in the work area fluctuates and when dust is present.

[0026] The distance sensor units can be distance sensor units of a safety device according to international patent application PCT / EP2021 / 054849. The distance sensor units can be signal-coupled to an evaluation unit of the safety device from international patent application PCT / EP2021 / 054849. The evaluation unit can be implemented as a component of a control unit of the robot assembly according to the invention.

[0027] A method for determining a minimum distance according to the international patent application PCT / EP2021 / 054849 can therefore be used to determine the distance using the distance sensor units.

[0028] Regarding the method for determining a minimum distance and the safety device with a distance sensor unit and an evaluation unit, reference is made to the international patent application PCT / EP2021 / 054849.

[0029] The method according to the international patent application PCT / EP2021 / 054849 for determining a minimum distance of an object from a device surface, in particular for determining a minimum distance of an object from a device surface of a handling device, comprises the following steps: Detecting a primary distance of the object by means of a first distance sensor unit positioned on or in the device surface, wherein the primary distance is the distance of the object from the distance sensor unit, determining a critical point which lies at the primary distance from the first distance sensor unit and within a detection range of the first distance sensor unit and which comes closest to the device surface taking into account a spatial course of the device surface, and determining the minimum distance of the critical point from the device surface.

[0030] Such a method can be carried out simply and reliably. In this context, it is taken into account that distance sensor units can usually determine a distance, but cannot specify where within the corresponding detection range the distance is measured. This problem is solved by determining the critical point and the corresponding minimum distance. This prevents the method from determining a minimum distance that is greater than the actual distance, for example due to a spatial configuration of the device surface. Rather, in cases of doubt, a distance that is slightly too small is output. The method is therefore particularly safe. In this context, the robot assembly according to the invention has a device surface. More precisely, the device surface is designed as a surface of the manipulator unit and / or as a surface of the effector unit.

[0031] The robot assembly according to the invention can also be designed as a handling device within the meaning of the international patent application PCT / EP2021 / 054849.

[0032] The following information must be known for the method: the profile of the device surface, at least in the relevant area, the position of the distance sensor unit on the device surface, and the detection range of the distance sensor unit. This information can easily be stored on a control unit configured to execute the method. It is also understood that the detection range of a distance sensor unit is always selected such that the device surface does not shield it. Otherwise, the distance sensor unit would not be operable with the desired reliability.

[0033] The safety device according to international patent application PCT / EP2021 / 054849 is suitable for a handling device having a device surface, in particular for a robot or robot assembly having a device surface. The safety device comprises a first distance sensor unit positionable on or in the device surface, i.e., on a surface of the manipulator unit and / or on a surface of the effector unit, and an evaluation unit that is signal-coupled to the distance sensor unit and is designed to carry out the method according to international patent application PCT / EP2021 / 054849 when the distance sensor unit is in the mounted state. Thus, by means of the safety device, minimum distances from device surfaces, i.e., from a surface of the manipulator unit and / or from a surface of the effector unit, can be determined easily and reliably.As a result, devices equipped with the safety device, for example the robot assembly according to the invention and in particular handling devices, can be operated reliably in work spaces in which objects potentially at risk of collision and in particular people are present.

[0034] The invention is explained below using various embodiments shown in the accompanying drawings. They show: Figure 1 shows a robot assembly according to the invention, which can be operated by means of a method according to the invention, in a first operating scenario, Figure 2 shows the robot assembly from Figure 1 In a second operating scenario, Figure 3, the robot assembly from the Figures 1 and 2 in a third operating scenario, and Figures 4 to 6 show an illustration of an adjustable detection range of two exemplary distance sensor units of the robot assembly from the Figures 1 to 3 .

[0035] Figure 1 shows a robot assembly 10 comprising a manipulator unit 12 and an effector unit 14.

[0036] In the illustrated embodiment, the manipulator unit 12 is designed as a robot arm having a first end fixed to a base 16.

[0037] The effector unit 14 is mounted at a second end of the robot arm. The second end of the robot arm is opposite the first end of the robot arm.

[0038] In the present case, the effector unit 14 is designed as a gripper unit.

[0039] The manipulation unit 12 further comprises three driven joints 18a, 18b, 18c. Each of these driven joints 18a, 18b, 18c is equipped with an actuator (not shown in detail), so that the effector unit 14 can be positioned and oriented essentially freely within a workspace 20 of the robot assembly 10.

[0040] The robot assembly 10 is operated within the framework of a human-robot cooperation.

[0041] This means that a human 22 can also be present in the workspace 20 of the robot assembly 10. Furthermore, objects can be present in the workspace 20, two of which are shown as examples. As will be explained below, collisions between the robot assembly 10 and these objects are to be prevented. For this reason, the two objects shown as examples are referred to as collision objects 24a, 24b.

[0042] Collisions of the robot assembly 10, ie the manipulator unit 12 or the effector unit 14 with the human 22 and the collision objects 24a, 24b are not desired.

[0043] The robot assembly 10 is therefore equipped with a plurality of distance sensor units 26. Some of the distance sensor units 26 are mounted on a surface of the manipulator unit 12. Other distance sensor units 26 are mounted on a surface of the effector unit 14. Overall, all distance sensor units are attached to a surface of the robot assembly 10.

[0044] All distance sensor units 26 serve to protect the robot assembly 10 from collisions.

[0045] For this purpose, all distance sensor units 26 are signal-coupled to a control unit 28. The driven joints 18a, 18b, 18c, in particular their actuators, are also signal-coupled to the control unit 28.

[0046] The distance sensor units 26 are designed to determine distances of the surface of the robot assembly 10 from the human 22 and the collision objects 24a, 24b.

[0047] Based on the distances determined by means of the distance sensor units 26, the driven joints 18a, 18b, 18c can be controlled by means of the control unit 28 to prevent collisions in such a way that a movement of the robot assembly 10 is slowed down, changed in direction, stopped or completely prevented.

[0048] In order to achieve this with high reliability, each of the distance sensor units 26 comprises two distance sensors 30a, 30b. This is shown in Figure 1 shown as an example only for one of the distance sensor units 26 (see detailed illustration). It is understood that the remaining distance sensor units 26 are constructed in the same way.

[0049] The distance sensors 30a, 30b use different sensor principles, with both distance sensors 30a, 30b operating according to a time-of-flight method.

[0050] In the illustrated embodiment, distance sensor 30a uses an optical sensor principle. Distance sensor 30b is an ultrasonic sensor.

[0051] The detection areas assigned to the distance sensors 30a, 30b are essentially identical.

[0052] The detection zones are shaped like a three-dimensional spherical segment, the center of which is formed by the distance sensor unit 26 or the distance sensors 30a, 30b encompassed by it, and which is spanned by an associated detection radius. Such detection zones are also referred to as conical or truncated conical. In the figures, the detection zones are symbolized by thin boundary lines b. For clarity, only some boundary lines are provided with a reference symbol.

[0053] In the robot assembly 10 shown, the detection radii can be changed during operation so that the size of the detection areas can be adjusted.

[0054] In this context, the control unit 28 is designed to change the detection radii and thereby adjust the size of the detection areas. This will be explained in more detail below.

[0055] The control unit 28 is further configured to execute a method for operating the robot assembly 10. In other words, the robot assembly 10 can be operated by means of the control unit 28.

[0056] For this purpose, the driven joints 18a, 18b, 18c of the robot assembly 10 are controlled depending on a task to be carried out by the robot assembly 10 and the detection results of the distance sensor units 26.

[0057] In Figure 1 In this context, an initial operating scenario is presented.

[0058] In a first step of the method for operating the robot assembly 10, a shutdown chamber 32 is provided. The shutdown chamber 32 is located within the workspace 20.

[0059] In the operating scenario according to Figure 1 the switch-off room 32 is separated from the other sections of the working room 20 by a safety device 34 in the form of a light barrier.

[0060] In this context, the light barrier can prevent the person 22 or the collision object 24a, with which no collision is allowed, from entering the switch-off room 32.

[0061] In this operating scenario, the collision object 24b is located within the shutdown room 32 and is not at risk of collision.

[0062] For this reason, only those distance sensor units 26 located outside the switch-off space 32 are operated to protect the robot assembly 10 against collisions.

[0063] Those distance sensor units 26 located within the switch-off chamber 32 are deactivated. Figure 1 This is symbolized by the fact that for those distance sensor units 26 which are located within the switch-off space 32, no boundary lines b symbolizing the detection area are shown.

[0064] Therefore, no sensor values ​​can originate from those distance sensor units 26 located within the shutdown space 32 that would cause a slowing down or stopping of a movement of the robot assembly 10. Accordingly, those sections of the robot assembly 10 located within the shutdown space 32 can be operated at a working speed that is limited only by the performance of the actuators of the driven joints 18a, 18b, 18c and, if applicable, a process to be performed by the robot assembly 10.

[0065] The situation is different for those sections of the robot assembly 10 located outside the shutdown area 32. These can only be operated at a working speed that always allows the relevant sections of the robot assembly 10 to be stopped in time or decelerated to a tolerated speed for collision protection.

[0066] In the operating scenario from Figure 1 the shutdown room 32 is designed as a stationary section of the working room 20.

[0067] It is understood that the Figure 1 shows a snapshot of the robot assembly 10.

[0068] Each of the distance sensor units 26 is deactivated upon entering the shutdown chamber 32. This is achieved by means of the control unit 28.

[0069] When leaving the shutdown compartment 32, each of the distance sensor units 26 resumes operation for collision protection. The control unit 28 is also used for this purpose.

[0070] For this purpose, the control unit 28 periodically checks whether each of the distance sensor units 26 is located inside or outside the shut-off chamber 32. For this purpose, the control unit 28 stores the locations of the robot assembly 10 where the individual distance sensor units 26 are mounted. Furthermore, the control unit 28 knows the respective position of the driven joints 18a, 18b, 18c.

[0071] Figure 2 shows a second operating scenario in which the robot assembly 10 is used to remove objects (not shown in detail) from a box 35.

[0072] The box 35 is dimensioned in such a way that it can be ruled out that the human 22 or one of the collision objects 24a, 24b moves into the box when a section of the robot assembly 10, more precisely the effector unit 14, is reaching into the box 35.

[0073] Thus, the interior of the box 35 is defined as the switch-off space 32.

[0074] Consequently, in the second operating scenario, the shutdown area 32 is also defined as being stationary within the working area 20 of the robot assembly 10.

[0075] However, since replacing the box 35 may result in a position of the box 35 within the work area 20 changing at least slightly, the position of the switch-off compartment 32 is taught in the second operating scenario. In other words, the position of the switch-off compartment 32 is taught.

[0076] In the second operating scenario, for example, the points marked with arrows 36 are approached and taught.

[0077] Furthermore, the explanations for the first operating scenario also apply to the second operating scenario.

[0078] A third operating scenario is in Figure 3 shown. In contrast to the previously explained operating scenarios, the shutdown space 32 is now defined depending on a pose of the robot assembly 10.

[0079] More specifically, two shutdown rooms 32a, 32b are provided in the third operating scenario.

[0080] In the illustrated pose of the robot assembly 10, the switch-off space 32a is inaccessible to the human 22 and to other collision objects, for example the collision objects 24a, 24b, due to the spatial arrangement of the components of the robot assembly 10.

[0081] The same applies to the shutdown space 32b, which is defined as a space between the robot assembly 10 and an environmental object 37, which in the present case is designed as a wall section.

[0082] For further information, please refer again to the explanations of the previous operating scenarios.

[0083] As already explained, a detection radius R can be set for each of the distance sensor units 26. The detection radii R are set using the control unit 28.

[0084] This will be explained below using the Figures 4 to 6 These explanations apply to all of the aforementioned operating scenarios.

[0085] Two adjacent distance sensor units 26 are arranged on a surface 38 of the robot assembly 10, which is only shown schematically. To simplify the following explanations, these distance sensor units are designated 26a and 26b.

[0086] In the initial situation, which is Figure 4 As shown, the distance sensor unit 26a is operated with a detection radius R, which is additionally designated R a for better differentiation. The distance sensor unit 26b is also operated with a detection radius R, which is designated R b for better differentiation. The detection radii R a , R b are essentially the same size.

[0087] Both distance sensor units 26a, 26b are located outside the switch-off compartment 32.

[0088] However, the distance sensor unit 26a is arranged adjacent to the switch-off chamber 32. A distance A of the distance sensor unit 26a from the switch-off chamber 32 is greater than the corresponding detection radius R a .

[0089] If the robot assembly 10 is now moved with the surface 38 in the direction of the switch-off space 32, the distance A of the distance sensor unit 26a from the switch-off space 32 decreases (see Figure 5compared to Figure 4 ).

[0090] To prevent collision objects within the switch-off space 32 from being detected by the distance sensor unit 26a, the detection radius Ra of the distance sensor unit 26a is set to this distance A. The distance A and the detection radius Ra are therefore essentially the same size.

[0091] At the same time, the detection radius R b is calculated based on the situation in the Figure 4 enlarged (see Figure 5 compared to Figure 4 ).

[0092] This ensures that detection gaps between the detection areas spanned by the detection radii R a , R b do not exceed a maximum size.

[0093] It is pointed out that in the illustrations according to Figures 4 to 6The detection areas are shown only in two dimensions. In the figures, the detection areas overlap, but this may not be the case everywhere in the room.

[0094] If the robot assembly 10 with the surface 38 is moved further in the direction of the switch-off space 32, the distance A of the distance sensor unit 26a from the switch-off space 32 can be reduced to zero. This is in Figure 6 shown.

[0095] At this position, the distance sensor unit 26a is deactivated, which is illustrated by the fact that it is no longer provided with boundary lines indicating the corresponding detection area. The detection radius Ra is zero in this situation.

[0096] In order to further protect the robot assembly 10 against collisions, the detection radius R b of the distance sensor unit 26b is increased again (see Figure 6 compared to Figure 5 ).

[0097] It is understood that the Figures 4 to 6 explained settings of the detection radii R a , R b run in the opposite directions when the robot assembly 10 is moved out of the switch-off space 32 or away from the switch-off space 32.

[0098] In addition, it is understood that the radius R a does not necessarily have to be set to the distance A (compare Figure 5and associated explanations). Rather, it is also possible to set the detection radius Ra so that it is smaller than the distance A. For example, the detection radius Ra can be set to 95% of the distance A. In this variant, a detection gap between the detection range of the distance sensor unit 26a and the switch-off space 32 is deliberately accepted. However, it is ensured that the size of this detection gap does not exceed a predetermined maximum size. In this way, the robot assembly 10 can be reliably protected against collisions. List of reference symbols

[0099] 10Robot assembly 12Manipulator unit 14Effector unit 16Floor 18aDriven joint 18bDriven joint 18cDriven joint 20Working space 22Human 24aCollision object 24bCollision object 26Distance sensor unit 26aDistance sensor unit 26bDistance sensor unit 28Control unit 30aDistance sensor 30bDistance sensor 32Shutdown space 32aShutdown space 32bShutdown space 34Safety device 35Box 36Arrow 37Environmental object 38Surface ADistance of a distance sensor unit from the shutdown space bBoundary line REDetection radius R a Detection radius R b Detection radius

Claims

1. Method for operating a robot assembly (10), wherein a plurality of distance sensor units (26) for collision protection of the robot assembly (10) is arranged on a surface (38) of the robot assembly (10), characterized in that the method comprises the following steps: - providing a shutdown space (32) which is defined within a working space (20) of the robot assembly (10) in a fixed manner or in dependence upon a pose of the robot assembly (10), wherein the shutdown space (32) is a section of the working space (20) of the robot assembly (10) in which it is possible to rule out an undesired collision of the robot assembly (10) or its components with a human and / or other objects, - operating the distance sensor units (26) that are located outside the shutdown space (32) for collision protection of the robot assembly (10), and - keeping the distance sensor units (26) that are located within the shutdown space (32) ineffective.

2. Method according to claim 1, wherein a fixedly, defined shutdown space (32) is a section of the working space (20) that is inaccessible to collision objects (24a, 24b) due to at least one surrounding object (37) or due to at least one safety device (34).

3. Method according to claim 1 or 2, wherein a shut-down space (32) that is defined in dependence upon a pose of the robot assembly (10) is a section of the working space (20) which is inaccessible to collision objects (24a, 24b) due to a spatial arrangement of components of the robot assembly (10) that are forming the pose.

4. Method according to one of the preceding claims, wherein the shutdown space (32) is learned.

5. Method according to one of the preceding claims, wherein each of the distance sensor units (26) is deactivated when it is moved into the shutdown space (32).

6. Method according to one of the preceding claims, wherein each of the distance sensor units (26) commences operation as it is moved out of the shutdown space (32) in order to protect the robot assembly (10) against collision.

7. Method according to one of claims 1 to 4, wherein a check is periodically performed as to whether each distance sensor unit (26) is located inside or outside the shutdown space (32).

8. Method according to one of the preceding claims, wherein a detection radius (R) of a distance sensor unit (26) that is positioned adjacent to a shutdown space (32) is set to a distance (A) of the distance sensor unit (26) from the shutdown space (32).

9. Method according to one of claims 1 to 7, wherein a detection radius (R) of a distance sensor unit (26) that is positioned adjacent to a shutdown space (32) is set smaller than a distance (A) of the distance sensor unit (26) from the shutdown space (32).

10. Method according to one of the preceding claims, wherein detection radii (R) of distance sensor units (26) which are arranged adjacent to one another on the surface (38) of the robot assembly (10) and which span adjacent or overlapping detection regions are matched to one another in such a manner that detection gaps that are located between the detection regions do not exceed a maximum size.

11. Robot assembly (10) having a manipulator unit (12) and / or an effector unit (14), a plurality of distance sensor units (26) for collision protection of the robot assembly (10), and a control unit (28), wherein the distance sensor units (26) are arranged on a surface (38) of the manipulator unit (12) and / or on a surface of the effector unit (14), and wherein the control unit (28) comprises means for implementing the method according to one of the preceding claims.

12. Robot assembly (10) according to claim 11, wherein the distance sensor units (26) operate according to a time-of-flight method.

13. Robot assembly (10) according to claim 11 or 12, wherein a detection radius (R) can be changed during operation for each distance sensor unit (26).

14. Robot assembly (10) according to one of claims 11 to 13, wherein each of the distance sensor units (26) comprises at least two distance sensors (30a, 30b).

15. Robot assembly (10) according to claim 14, wherein the distance sensors (30a, 30b) of a distance sensor unit (26) use different sensor principles, in particular wherein one of the distance sensors (30a, 30b) uses an electromagnetic, preferably optical, sensor principle and another of the distance sensors (30a, 30b) uses an acoustic sensor principle.