Safety device for protecting hazardous area of automatically operated machine, in particular robot

Abstract

A safety device for protecting a hazardous area of an automatically operated machine, in particular a robot (18), has a plurality of sensors (12-1 to 12-6) which are mechanically coupled to the machine during operation of the machine such that the sensors (12-1 to 12-6) rotate together with the machine or with a machine body portion (24, 26) in a current direction of rotation (22). The analysis and control unit (14, 28) controls the rotation of the machine body part (24, 26) as a function of the sensor signal. The safety device comprises a first sensor (12-1) for monitoring a defined first space section (32-1), a second sensor (12-2) for monitoring a defined second space section (32-2), and a third sensor (12-3) for monitoring a defined third space section (32-3). The first spatial section, the second spatial section, and the third spatial section are different from each other. The first space section (32-1) and the second space section (32-2) adjoin each other. In addition, the second space section (32-2) and the third space section (32-3) adjoin one another. During operation of the machine, the first spatial section (32-1), the second spatial section (32-2) and the third spatial section (32-3) are distributed about the axis of rotation (20) such that the first spatial section (32-1), the second spatial section (32-2) and the third spatial section (32-3) follow one another in a current direction of rotation (22) of the machine body part (24, 26).

Description

[0001] The present invention relates to a safety device for protecting a dangerous area of an automatically operating machine, in particular for protecting a dangerous area of a robot, wherein the machine has a machine body part that performs a rotational movement about a rotational axis during machine operation and thereby defines a current rotational direction, the safety device comprising a plurality of sensors configured to be mechanically coupled to the machine body part such that the plurality of sensors move with the machine body part in the current rotational direction during machine operation, and the safety device comprising an evaluation and control unit configured to control the rotational movement of the machine body part in response to sensor signals from the plurality of sensors, wherein the plurality of sensors comprise a first sensor that monitors a defined first spatial sector and generates a first sensor signal when an object is detected in the first spatial sector, wherein the plurality of sensors comprise a second sensor that monitors a defined second spatial sector and generates a second sensor signal when an object is detected in the second spatial sector, and wherein the plurality of sensors comprise a third sensor that monitors a defined third spatial sector and generates a third sensor signal when an object is detected in the third spatial sector, wherein the first spatial sector, the second spatial sector and the third spatial sector are different from each other, wherein the first spatial sector and the second spatial sector are adjacent to each other during machine operation, and wherein the second spatial sector and the third spatial sector are adjacent to each other during machine operation.

[0002] Such a safety device is known from EP 3 909 727A1.

[0003] For many years, there has been a desire and an effort to protect the dangerous area caused by the rapid movement of robots as simply and flexibly as possible in order to prevent accidents and injuries. In particular, a safety device is desired that allows a person to stay near the robot and perform any activity, for example to enable a person and a robot to work together. This effort is called human-robot collaboration. The two-part standard EN ISO 10218 defines the requirements for collaborative operation of robots. For example, in the case of contact between a robot and a person, a predefined contact force on the person must not be exceeded. Therefore, it is known that the position, force and / or torque and / or speed of the movement of a robot or a part of the robot body must be monitored and, if necessary, limited. Monitoring and limitation must also be ensured in the event of a fault, for example if a component fails or in the case of a software error, i.e. it must be fail-safe.

[0004] Hereinafter, the term "fail-safe" is used to mean that a component or arrangement meets the requirements of category 3 or the so-called performance level PL d according to standard EN ISO 13849-1 and / or the safety requirement level SIL 3 according to standard IEC 61508 and the machine-specific industry standard EN62061.

[0005] EP 3 909 727 A1 discloses a safety device having a total of six presence sensors, all of the presence sensors among the presence sensors being arranged on a U-shaped holder. On each of the two legs of the U-shaped holder, three presence sensors are respectively arranged vertically one above the other. The respective opposite sensors "look" in opposite directions and monitor the areas at the sides of the robot. The holder having the six presence sensors is arranged on a linkage, which in turn is attached to a robot arm. The linkage moves in a direction opposite to the movement of the robot arm, such that the holder having the presence sensors always remains in a horizontal position and maintains the vertical alignment of the sensors. The presence sensors arranged one above the other on each side respectively monitor a spherical sector space segment. The space segments are vertically staggered on each side and thus monitor the spatial area at the side of the robot, which is located at different heights and lateral distances from the robot. The two lowest sensors on each side monitor the area close to the robot. If a person or an object is detected in this close range, the movement of the robot is stopped. The two intermediate sensors on each side monitor a farther area. If a person or an object is detected in this farther area, the robot moves at a reduced speed.

[0006] WO 2018 / 145990 A1 discloses another safety device for protecting a robot. On the one hand, the known device uses a sensor permanently installed in the occupancy area of the robot, which can be, for example, a safety mat, a laser sensor, a camera or an ultrasonic sensor. The permanently installed sensor is used to monitor the occupancy area around the robot. Additionally, the safety device of WO 2018 / 145990 A1 includes another sensor at the free end of the robot arm in the area of a so-called end effector. This another sensor is arranged vertically above the end effector and monitors an umbrella-shaped downward-facing sensor field. The additional sensor can be a laser sensor, a camera or an ultrasonic sensor. The ground-level sensor field of the permanently installed sensor can be divided into a number of concentric sub-circles, where each sub-circle is assigned a different safety level. The different safety levels can be associated with different movement speeds of the robot.

[0007] WO 2006 / 024431 A1 discloses another safety device for protecting a robot. The device includes eight ultrasonic proximity sensors permanently installed in the floor area of the robot, and each of the proximity sensors monitors a defined sector. The monitored sectors are distributed around the robot like a fan within an angular range of approximately 180°. The safety device further includes a fence or a light barrier for preventing lateral approach to the robot behind the monitored sectors, and a rear-mounted laser scanner for monitoring the fence area on the back of the robot at the ground plane. The safety controller ensures that the robot switches to a slower mode or even stops if a person moves into a sector within the current position range of the robot arm.

[0008] The known safety devices are in principle suitable for achieving safe operation of the robot. However, they partly impair the productivity of the robot because, for safety reasons, the movement speed of the robot is usually limited to a very slow speed, even if this is not necessary during closer inspections. In addition, some of the known safety devices require a large number of sensors for monitoring a static spatial area around the robot.

[0009] Against this background, the object of the present invention is to provide a safety device of the type initially described, which is capable of protecting a robot or a similar machine in an efficient manner. In particular, the object is to provide a safety device which is capable of achieving a high productivity of the robot without endangering a person in the vicinity of the robot.

[0010] According to one aspect of the present invention, there is provided a safety device of the above-mentioned type for achieving these objects, wherein a first spatial sector, a second spatial sector and a third spatial sector are distributed around a rotation axis during machine operation such that when the machine body part rotates around the rotation axis, the first spatial sector, the second spatial sector and the third spatial sector follow one another in the current rotation direction. Preferably, the new safety device is used for protecting a multi-axis robot having a serial kinematic mechanism, in particular for protecting an articulated arm robot or a SCARA robot. In a particularly preferred exemplary embodiment, the machine body part is a robot arm part rotating about a vertical rotation axis.

[0011] The sensors of the aforementioned new safety device are rigidly connected to the rotating machine body part and thus change their current "viewing direction" in response to the rotational movement of the machine body part. The spatial sectors rotate around the rotation axis together with the machine body part and are thus quasi-stationary relative to the moving machine body part. However, the monitored spatial sectors move relative to a fixed point near the machine. This differentiates the new safety device from the concept of using fixed sensors for monitoring a static spatial area. The new safety device allows for use with a relatively small number of sensors, which contributes to an efficient and cost-effective implementation.

[0012] In addition, the monitored spatial sectors are adjacent to each other in the plane of rotation and thus follow each other as the machine body part rotates. The plane of rotation is substantially perpendicular to the axis of rotation, in particular orthogonal to the axis of rotation. This means that the monitored spatial sectors sweep over the same spatial region one after another along the current direction of rotation. Therefore, the new safety device conceptually differs from the safety device of the aforementioned EP 3 909 727 A1. At least three spatial sectors following or guiding each other make it possible to increase the productivity of the machine by triggering a low-speed creep speed or a safety stop only when the object to be protected, such as a person or a part of the human body, is directly within the movement range of the moving machine body part. Due to the arrangement of the moving spatial sectors, the movement path of the machine body part can be divided into very critical spatial regions and less critical spatial regions in a very simple and cost-effective manner. Compared with known safety devices, the safety distance for triggering the safety function can be reduced. Unnecessary low-speed creep movements can be minimized. However, at the same time, the rotating spatial sectors mean that if a person is directly in front of the machine body part in the current direction of rotation, a safety stop or a creep speed can be triggered at any time.

[0013] Therefore, the above object is fully achieved.

[0014] Preferably, each of the above-mentioned sensors is a radar sensor, because radar radiation with electromagnetic waves from the microwave range is very robust against fog, dust, dirt, flying sparks or rain. In a preferred exemplary embodiment, the radar sensor operates at an operating frequency in the range of 10 GHz to 80 GHz, preferably at an operating frequency in the range between 20 GHz and 30 GHz or at an operating frequency in the range between 60 GHz and 70 GHz. These frequency ranges are capable of quickly and accurately detecting a collision object even when the above environmental factors impair the "clear view". This makes these sensors very suitable for harsh industrial environments. Alternatively, the above-mentioned sensors can in principle be lidar sensors, cameras or ultrasonic sensors that work with light from the optical and / or infrared wavelength ranges. For multiple sensors, a combination of different sensor principles can also be envisaged.

[0015] In a preferred refinement, the sensors each monitor a sector of the pie-shaped space that extends from the respective sensor over an azimuthal opening angle that is greater than the opening angle in height. Preferably, the azimuthal opening angle lies in the plane of rotation of the respective sensor. The opening angle in height is preferably defined parallel to the axis of rotation. In some advantageous exemplary embodiments, the azimuthal opening angle lies in the range between 20° and 120°, and the opening angle in height lies in the range between 10° and 30°. Adjacent space sectors can overlap at their respective boundaries. Preferably, the angular range of overlap of adjacent space sectors is smaller compared to the respective opening angles. In a preferred exemplary embodiment, the azimuthal overlap angle of two adjacent space sectors is at most 20%, preferably at most 10%, of the respective azimuthal opening angle. Thus, each of the three sensors mentioned above monitors more than half of the space sector assigned to it. Preferably, each of the three sensors mentioned above monitors more than 75% of the space sector assigned to it.

[0016] This refinement makes a favorable contribution to maximizing the productivity of the machine by reducing or even avoiding unnecessary error stops and slow-down movements of the machine and triggering the safety function in the form of a stop or slow-down movement only in cases where it is necessary, by means of the new safety device.

[0017] In another refinement, the evaluation and control unit is configured to limit the rotational speed of the machine body part about the axis of rotation in a fail-safe manner to a defined value greater than zero in response to the first sensor signal, the second sensor signal, and the third sensor signal.

[0018] In this refinement, in the absence of any interference, the machine body part moves at a reduced rotational speed compared to machine operation. When an object is detected in the respective space sector guided in the rotational direction, the so-called slow-down speed of the machine body part advantageously contributes to maintaining the productivity of the machine, despite the slower movement due to the risk of collision in the space sector guided in the rotational direction.

[0019] In another refinement, the machine body part has a profile guided in the current rotational direction, wherein the first space sector is arranged in front of the guided profile in the current rotational direction, wherein the second space sector is arranged in front of the first space sector in the current rotational direction, wherein the third space sector is arranged in front of the second space sector in the current rotational direction, and wherein the evaluation and control unit is configured to rotate the machine body part selectively about the axis of rotation at a first speed or at a second speed, wherein the first speed is higher than the second speed, and wherein, if the first sensor signal indicates that there is no object in the first space sector, the evaluation and control unit rotates the machine body part about the axis of rotation at the first speed.

[0020] In this improvement, if the space sector immediately in front in the current rotation direction is free, or correspondingly, if the assigned sensor does not detect a potential collision object in the first space sector immediately in front, the new safety device allows the machine body part to move at a speed higher than the slow travel speed. Therefore, in this improvement, allowing the machine body part to move at high speed depends respectively and decisively on the state in the first guiding space sector or the sensor signal of the first guiding sensor. This improvement enables the machine body part to rotate at high speed even if an object is detected in another guiding space sector or a subsequent space sector. This improvement achieves a particularly high productivity because the number and / or duration of slow travel movements with low productivity are reduced.

[0021] In another improvement, if the first sensor signal indicates an object in the first space sector, the evaluation and control unit limits the current rotational speed of the machine body part about the axis of rotation to a second speed.

[0022] In this improvement, if a potential collision object is detected in the first guided space sector, the machine body part is restricted to the slow travel speed by the new safety device. This improvement ensures a high level of operational safety and advantageously contributes to the safe operation of the monitored machine while maintaining high productivity.

[0023] In another improvement, the evaluation and control unit is configured to reverse the direction of rotation of the machine body part and selectively rotate the machine body part about the axis of rotation at a first speed when a third sensor signal indicates that there is no object in the third space sector.

[0024] In this improvement, when the direction of rotation of the machine body part is reversed, the decisive role of the guided space sector changes from the first sensor to the third sensor. This improvement advantageously contributes to the dynamic adaptation protection of the machine.

[0025] In another improvement, the evaluation and control unit has a fail-safe first evaluation and control unit and a non-fail-safe second control unit, wherein the second control unit controls the movement of the machine body part in response to the operating program and in response to a binary enabling signal from the first evaluation and control unit, and wherein the first evaluation and control unit generates the binary enabling signal in response to the first sensor signal, the second sensor signal, and the third sensor signal.

[0026] As mentioned above, in this case, "fail-safe" means that the first evaluation and control unit meets the requirements of Category 3 or the so-called Performance Level PL d according to the standard EN ISO 13849-1 and / or the safety requirement level SIL 3 according to the standard IEC 61508 or the machine-specific industry standard EN 62061. In contrast, the second control unit does not meet these requirements. Therefore, it is a so-called standard control unit that basically controls the desired operating sequence of the machine according to the operating procedure. This improvement enables the machine to operate safely and productively in a cost-effective manner. In particular, this improvement allows machines that were previously protected in different ways to be retrofitted with new safety devices and thus achieve increased productivity without significant changes to the desired operating sequence.

[0027] Preferably, the first evaluation and control unit generates two mutually redundant binary enable signals, and each of the binary enable signals can have a high signal level (on state) or a low signal level (off state). The high signal level indicates that the first spatial sector, especially guided in the rotational direction, is free. Then, the second control unit can rotate the machine body part at a high rotational speed if this is expected in the desired operating sequence. Therefore, the high signal level is a fail-safe enable signal for the high rotational speed. On the other hand, the low signal level indicates the absence of the enable signal, which means that the second control unit moves the machine body part at most at a limited slow rotational speed. Preferably, the first evaluation and control unit generates two redundant binary enable signals, and each of the two redundant binary enable signals has a test pulse, i.e., a defined pulse from the high signal level to the low signal level. The test pulse enables the detection of a fixed high-level fault in the output circuit of the first evaluation and control unit. Preferably, the test pulses of the two mutually redundant binary enable signals are out of phase with each other, which enables advantageous cross-circuit detection. This improvement enables a simple hard-wired synchronous information exchange between the first evaluation and control unit and the non-fail-safe second control unit.

[0028] In another improvement, the first sensor, the second sensor, and the third sensor are connected in series to the evaluation and control unit.

[0029] In a preferred exemplary embodiment, the series connection includes a serial bus, especially a CAN bus for example, via which the sensors communicate with the (first) evaluation and control unit. This improvement simplifies the installation of the sensors on the machine and contributes to a very cost-effective implementation.

[0030] In another improvement, at least one of the plurality of sensors has a first detection area and a separate second detection area within an associated spatial sector, where the first detection area is closer to the sensor than the second detection area, where the sensor generates a separate sensor signal for each of the two detection areas, and where the evaluation and control unit is configured to control the rotation of the machine body part in response to the separate sensor signals.

[0031] In this improvement, the spatial sector of at least one sensor is divided into two different distance ranges. Advantageously, all of the sensors among the plurality of sensors have such a first detection range and a separate second detection range within the respective monitored spatial sectors. This improvement enables the evaluation and control unit to trigger different reactions in a simple manner based on the distance of an object in the monitored spatial sector. Advantageously, the evaluation and control unit can generate an optical and / or acoustic warning signal in the case of a relatively long distance in order to prevent a person from further entering the working area of the machine. On the other hand, when an object is detected at a relatively short distance, the evaluation and control unit can immediately reduce the movement speed of the machine body part and / or stop the movement of the machine body part. Alternatively, once the warning signal is generated, the evaluation and control unit can also reduce the rotation speed of the machine body part. This improvement helps to achieve high productivity and the safe operation of the machine.

[0032] In another improvement, a plurality of sensors form a first sensor group and a second sensor group, where the sensors of the first sensor group define a first plane during the operation of the machine, where the sensors of the second sensor group define a second plane during the operation of the machine, and where the first plane is vertically below the second plane.

[0033] This improvement enables the mobile machine body part to be advantageously comprehensively protected with a small number of sensors. In a preferred exemplary embodiment, the first plane is close to the floor, that is, the monitored spatial sectors of the sensors from the first sensor group extend downward to the floor. It can be said that they rest on the floor. The sensors of the first sensor group advantageously have a main observation direction that is substantially perpendicular to the axis of rotation. In contrast, in a preferred exemplary embodiment, the main observation direction of the sensors of the second sensor group extends at an angle with respect to the main observation direction of the sensors of the first sensor group, particularly at an angle with respect to the floor. The sensors of the first sensor group can be used to effectively monitor the spatial area around the mobile machine body part but not the mobile machine body part itself. On the other hand, the sensors of the second sensor group can be used to monitor the spatial area in front of the mobile machine body part radially, as if the sensors of the second sensor group monitor from above the diagonal, and the machine body part does not block the line of sight of the sensors of the second sensor group.

[0034] Thus, in another improvement, the sensors of the first sensor group jointly monitor an azimuthal spatial region that does not include the machine body part. In another improvement, the sensors of the second sensor group jointly monitor an azimuthal spatial region that extends behind the machine body part as seen by the sensors of the second sensor group.

[0035] Through these improvements, effective and favorable comprehensive protection for the moving machine body part can be achieved. If comprehensive protection is not required, for example, because a fence or other separate protection device prevents the moving machine part from approaching from some radial directions, the unnecessary sensor groups can be omitted in a cost-effective manner.

[0036] In another improvement, the machine body part performs a rotational movement within a defined range of rotational angles during machine operation, wherein the first spatial sector, the second spatial sector, and the third spatial sector each cover a sub-range of the defined range of rotational angles.

[0037] In some preferred exemplary embodiments, the sizes of the sub-ranges covered by the first spatial sector, the second spatial sector, and the third spatial sector are substantially equal. For example, the first spatial sector, the second spatial sector, and the third spatial sector each cover one-third of the defined range of rotational angles. In other exemplary embodiments, the first spatial sector and the third spatial sector each cover a larger sub-range of rotational angles compared to the second spatial sector. In some exemplary embodiments, the first spatial sector, the second spatial sector, and the third spatial sector each cover a range of rotational angles between 45° and 90°.

[0038] This improvement enables very effective protection of the robot working unit with a small number of sensors.

[0039] It should be understood that, without exceeding the scope of the present invention, the features mentioned above and the features to be explained below can be used not only in the combinations indicated in each case, but also in other combinations or in independent situations.

[0040] Exemplary embodiments of the present invention are shown in the drawings and will be explained in more detail in the following description. The drawings show:

[0041] Figure 1 is an exemplary embodiment of a new safety device on an articulated robot,

[0042] Figure 2 is Figure 1 the safety device, wherein three monitored spatial sectors are schematically shown,

[0043] Figure 3 is Figure 1safety device, in which three additional monitored spatial sectors are schematically shown.

[0044] In Figure 1 , an exemplary embodiment of the new safety device is generally designated by the reference numeral 10. In this exemplary embodiment, the safety device 10 includes six radar sensors 12-1, 12-2, 12-3, 12-4, 12-5, and 12-6, collectively designated hereinafter by the reference numeral 12, and a fail-safe evaluation and control unit 14 that is connected to the radar sensors 12 via a serial bus connection 16 (only schematically shown herein). In a preferred exemplary embodiment, the serial bus connection 16 is based on the CAN bus protocol, which enables very efficient data transfer between the serially connected sensors and the evaluation and control unit 14. In some exemplary embodiments, the evaluation and control unit 14 includes a fail-safe controller called PNOZmulti2, which is commercially available from the applicant Pilz GmbH & Co KG, 73760 Ostfildern, Germany.

[0045] In this case, the sensor 12 is arranged on the articulated arm robot 18 and can thus rotate together with the robot 18 about the axis of rotation 20 of the robot 18. In this case, the axis of rotation 20 is the first axis of rotation among a plurality of axes of rotation of the robot 18, and the axis of rotation 20 extends perpendicular to the floor on which the robot 18 is placed with its base. In some exemplary embodiments, the robot 18 can perform pick-and-place tasks, whereby it rotates about the axis of rotation 20 in alternating directions. The corresponding current direction of rotation is indicated by the reference numeral 22. As is known to those skilled in the art, the robot 18 has a number of arm portions rotatably connected to each other via additional rotational joints here. Some of these arm portions are denoted here by the reference numerals 24, 26. The rotation of the arm portions 24, 26 relative to each other and the rotation of the robot 18 about the axis of rotation 20 are controlled here by the non-failsafe control unit 28. The control unit 28 can be a conventional robot controller, such as a robot controller typically provided by the manufacturer of the robot 18 and supplied together with the robot. The control unit 28 controls the desired sequence of operations of the robot 18 in a manner known per se according to the operating program typically loaded into the control unit 28. In some preferred exemplary embodiments, the evaluation and control unit 14 of the robot and the operating control unit 28 can communicate with each other via a bidirectional connection 29. In some exemplary embodiments, the connection 29 can include, for example, a failsafe bus connection based on the failsafe Ethernet protocol. In a preferred exemplary embodiment, the connection 29 includes two or more redundant binary enable signals 29a, 29b, so-called OSSD signals, such as those provided by the applicant's failsafe controller PNOZmulti 2.

[0046] Depending on the operating situation, the movable arm portions 24, 26 form a profile 30 guided in the current direction of rotation 22, which can exert a high contact force on a person or another object (not shown here) in the event of a collision with a person or an object within the rotation range of the robot 18. To prevent this, the sensors 12 each monitor a defined assigned spatial sector 32. In Figure 1 FIG., the first spatial sector 32-1, the second spatial sector 32-2 and the third spatial sector 32-3 are each indicated by a dashed line. By way of example, in this case, the first sensor 12-1 monitors the first spatial sector 32-1, the second sensor 12-2 monitors the second spatial sector 32-2, and the third sensor 12-3 monitors the third spatial sector 32-3. The three spatial sectors 32-1, 32-2 and 32-3 are adjacent to each other, and the sensors 12-1, 12-2 and 12-3 define a plane 34, in this case, the plane 34 is close to the ground and is substantially parallel to the ground. Figure 2Three spatial sectors 32-1, 32-2, and 32-3 are shown in a perspective view.

[0047] As can be seen from Figure 2 it, the monitored spatial sectors 32-1, 32-2, and 32-3 overlap from a certain distance in the adjacent area such that the three sensors 12-1, 12-2, and 12-3 together cover a continuous angular range of rotation 36 here, and the angular range of rotation 36 here surrounds the robot 18 on three sides. In the illustrated exemplary embodiment, the spatial sectors 32-1, 32-2, and 32-3 together cover an angular range of rotation 36 of approximately 270°. In this case, each of the three sensors 12-1, 12-2, and 12-3 monitors the spatial sector 32-1, 32-2, and 32-3 assigned to it, and the corresponding sector covers approximately one-third of the angular range of rotation 36. The jointly monitored angular range of rotation 36 extends in the azimuthal direction and does not include the robot 18 and the machine body parts 24, 26. Thus, in this exemplary embodiment, the machine body parts 24, 26, and more generally, the robot 18 do not produce any radar reflections that can be detected by the sensors 12-1, 12-2, and 12-3.

[0048] In some exemplary embodiments, dividing the azimuthal spatial sector 36 into three monitored spatial sectors 32-1, 32-2, 32-3 of approximately equal size has proven to be very advantageous, such that a small number of sensors are used to monitor the angular range of rotation of the robot 18, enabling the robot 18 to operate with a high level of productivity. Advantageously, if the immediately preceding spatial sector in the current direction of rotation is "idle", i.e., the assigned sensor does not detect any potential collision objects in the spatial sector it is monitoring, the fail-safe evaluation and control unit 14 generates the above-mentioned enabling signal. Thus, for example, if the robot 18 rotates clockwise in a defined operating situation, the evaluation and control unit 14 generates the above-mentioned enabling signal if the spatial sector 32-1 is idle, i.e., if the first sensor 12-1 does not detect a collision object in the spatial sector 32-1. Conversely, if the robot 18 rotates counterclockwise in another operating situation and the spatial sector 32-3 is idle, i.e., if the third sensor 12-3 does not detect a collision object in the spatial sector 32-3, the evaluation and control unit 14 generates the above-mentioned enabling signal. Regardless of this exemplary embodiment, in additional exemplary embodiments in which the machine body parts 24, 26 pass through an angular range of rotation of less than or equal to 300° during the intended operation, it is advantageous for the safety device 10 to monitor the angular range of rotation using three, four, or at most five spatial sectors that together cover the entire angular range of rotation.

[0049] As in Figure 2It can also be seen that, in this case, the monitored spatial sectors 32-1, 32-2, 32-3 each have a shape similar to a slice of pie or cake, i.e., a sector corresponding to a circle in a plan view, but are limited in height. In other words, in Figure 1 the azimuth opening angle 38 indicated by reference numeral 38 for the spatial sector 32-3 in is greater than the opening angle 40 in height.

[0050] In a preferred exemplary embodiment, some or even all of the plurality of sensors 12-1 to 12-6 have a first detection area 42 and a separate second detection area 44 in the respective monitored spatial sectors (indicated by the example of using the first sensor 12-1 in Figure 1 . The first detection area 42 is positioned closer to the respective sensor than the second detection area 44. The respective sensor generates a separate sensor signal for each of the two detection areas 42, 44, and the evaluation and control units 14, 28 are configured to control the rotation of the machine body parts 24, 26 in response to the separate sensor signals. The separate detection areas 42, 44 enable the current distance of potential collision objects to the robot 18 to be taken into account when controlling the rotational movement. For example, if an object is detected in the more distant second detection area 44, the evaluation and control units 14, 28 can trigger only a visual and / or audible warning signal, and only the detection of an object in the first detection area 42 triggers a reduction in the current rotational speed or even an emergency stop. In a further exemplary embodiment, the evaluation and control units 14, 28 can be configured to limit the current rotational speed of the machine body part in the case of detecting an object in the more distant detection area 44, or to reduce the current rotational speed to a slow travel speed, while the detection of an object in the closer detection area 42 always triggers an emergency stop. In principle, the monitored spatial sectors can also have more than two separate detection areas staggered in distance, whereby the evaluation and control units 14, 28 are configured to control the rotational movement of the machine body part in response to the azimuth position of the object (detected by means of the respective spatial sector or sensor signal) and the respective distance (detected by means of the respective detection area).

[0051] In Figure 1 the exemplary embodiment shown, the safety device 10 has two sensor groups with a total of 6 sensors. The sensors 12-1, 12-2, and 12-3 form the first sensor group and define a plane 34 close to the ground. The sensors 12-4, 12-5, and 12-6 are arranged on a platform above the sensors 12-1, 12-2, and 12-3 and form the second sensor group. The sensors 12-4, 12-5, and 12-6 of the second sensor group hereby define a plane 46 vertically above the plane 34. As can be seen from Figure 1 and Figure 3As can be seen, sensors 12-4, 12-5, and 12-6 of the second sensor group together monitor another azimuthal spatial region 48, as seen through sensors 12-4, 12-5, and 12-6 of the second sensor group, which extends behind the robot 18 or its machine body parts 24, 26. The viewing directions of sensors 12-4, 12-5, and 12-6 of the second sensor group are inclined downwardly from a position slightly above the robot 18. Thus, the spatial sectors monitored by sensors 12-4, 12-5, and 12-6 particularly cover Figure 2 the gap left by the azimuthal spatial region 36 as shown therein.

Claims

1. A safety device for protecting a dangerous area of a machine with automated operation, in particular for protecting a dangerous area of a robot (18), the machine having a machine body part (24, 26) which performs a rotational movement about a rotational axis (20) during machine operation and thereby defines a current rotational direction (22), the safety device comprising a plurality of sensors (12-1 to 12-6), the plurality of sensors (12-1 to 12-6) being configured to be mechanically coupled to the machine body part (24, 26) such that the plurality of sensors (12-1 to 12-6) move along the current rotational direction together with the machine body part (24, 26) during machine operation, and the safety device comprising an evaluation and control unit (14, 28), the evaluation and control unit (14, 28) being configured to control the rotational movement of the machine body part (24, 26) in response to sensor signals from the plurality of sensors (12-1 to 12-6), wherein, The plurality of said sensors (12-1 to 12-6) includes a first sensor (12-1) that monitors a defined first spatial sector (32-1) and generates a first sensor signal when an object is detected in the first spatial sector (32-1), wherein the plurality of said sensors (12-1 to 12-6) includes a second sensor (12-2) that monitors a defined second spatial sector (32-2) and generates a second sensor signal when an object is detected in the second spatial sector (32-2), and wherein the plurality of said sensors (12-1 to 12-6) includes a third sensor (12-3) that monitors a defined third spatial sector (32-3) and generates a third sensor signal when an object is detected in the third spatial sector (32-3), wherein the first spatial sector (32-1), the second spatial sector (32-2), and the third spatial sector (32-3) are different from each other, wherein the first spatial sector (32-1) and the second spatial sector (32-2) are adjacent to each other during machine operation, and wherein the second spatial sector (32-2) and the third spatial sector (32-3) are adjacent to each other during machine operation, characterized in that the first spatial sector (32-1), the second spatial sector (32-2), and the third spatial sector (32-3) are distributed around the rotation axis (20) during machine operation such that when the machine body parts (24, 26) rotate about the rotation axis (20), the first spatial sector (32-1), the second spatial sector (32-2), and the third spatial sector (32-3) follow each other in the current rotation direction (22).

2. The safety device according to claim 1, characterized in that, The plurality of said sensors (12-1 to 12-6) each monitors a pie-shaped spatial sector (32-1, 32-2, 32-3) that extends from the respective sensor over an azimuthal opening angle (38) greater than the height opening angle (40).

3. The safety device according to claim 1 or 2, characterized in that, The machine body parts (24, 26) have a profile (30) guided in the current rotational direction (22), wherein the first spatial sector (32-1) is arranged in front of the guided profile (30) in the current rotational direction (22), wherein the second spatial sector (32-2) is arranged in front of the first spatial sector (32-1) in the current rotational direction (22), wherein the third spatial sector (32-3) is arranged in front of the second spatial sector (32-2) in the current rotational direction (22), and wherein the evaluation and control unit (14, 28) is configured to rotate the machine body parts (24, 26) selectively at a first speed or at a second speed about the rotational axis (20), wherein the first speed is higher than the second speed, and wherein, when the first sensor signal indicates that there is no object in the first spatial sector (32-1), the evaluation and control unit (14, 28) rotates the machine body parts (24, 26) at the first speed about the rotational axis (20).

4. The safety device according to claim 3, characterized in that, When the first sensor signal indicates an object in the first spatial sector (32-1), the evaluation and control unit (14, 28) limits the current rotational speed of the machine body parts (24, 26) about the rotational axis (20) to the second speed.

5. The safety device according to claim 3 or 4, characterized in that, The evaluation and control unit (14, 28) is configured to reverse the current rotational direction of the machine body parts (24, 26) and selectively rotate the machine body parts (24, 26) at the first speed about the rotational axis (20) when the third sensor signal indicates that there is no object in the third spatial sector (32-3).

6. The safety device according to any one of claims 1 to 5, characterized in that, The evaluation and control unit includes a fail-safe first evaluation and control unit (14) and a non-fail-safe second control unit (28), wherein the second control unit (28) controls the movement of the machine body parts (24, 26) in response to an operating program and in response to binary enable signals (29a, 29b) from the first evaluation and control unit (14), and wherein the first evaluation and control unit (14) generates the binary enable signals (29a, 29b) in response to the first sensor signal, the second sensor signal, and the third sensor signal.

7. The safety device according to any one of claims 1 to 6, characterized in that, The first sensor (12-1), the second sensor (12-2), and the third sensor (12-3) are connected to the evaluation and control unit (14, 28) in a series connection.

8. The safety device according to any one of claims 1 to 7, characterized in that, At least one of the plurality of sensors (12-1 to 12-6) has a first detection area (42) and a separate second detection area (44) within an associated spatial sector, wherein the first detection area (42) is closer to the sensor than the second detection area (44), wherein the at least one sensor generates a separate sensor signal for each of the two detection areas (42, 44), and wherein the evaluation and control unit (14, 28) is configured to control the rotation of the machine body part (24, 26) in response to the separate sensor signals.

9. The safety device according to any one of claims 1 to 8, characterized in that, The plurality of sensors (12-1 to 12-6) form a first sensor group and a second sensor group, wherein the sensors (12-1, 12-2, 12-3) of the first sensor group define a first plane (34) during machine operation, wherein the sensors (12-4, 12-5, 12-6) of the second sensor group define a second plane (46) during machine operation, and wherein the first plane (34) is vertically below the second plane (46).

10. The safety device according to claim 9, characterized in that, The sensors (12-1, 12-2, 12-3) of the first sensor group jointly monitor an azimuthal spatial region (36) that does not include the machine body part (24, 26).

11. The safety device according to claim 9 or 10, characterized in that, The sensors (12-4, 12-5, 12-6) of the second sensor group jointly monitor another azimuthal spatial region (48) seen through the sensors (12-4, 12-5, 12-6) of the second sensor group, and the another azimuthal spatial region (48) extends behind the machine body part (24, 26).

12. The safety device according to one of claims 1 to 11, characterized in that, The machine body part (24, 26) performs a rotational movement within a defined rotational angle range (36) during machine operation, wherein the first spatial sector (32-1), the second spatial sector (32-2), and the third spatial sector (32-3) each cover a partial range of the defined rotational angle range (36).

13. An automatically operating machine having a machine body part (24, 26) that performs a rotational movement about a rotational axis (20) during machine operation and thereby defines a current rotational direction (22), the automatically operating machine comprising a safety device (10) according to any one of claims 1 to 12.

14. The automatic operation machine according to claim 13, wherein, The machine body part (24, 26) is a robot arm part that rotates particularly about a vertical rotational axis (20).

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