Safety devices for protecting danger zones in automatically operated machines, especially robots

Abstract

A safety device for protecting danger areas of an automatically operated machine, particularly a robot (18), is provided. The safety device includes a plurality of sensors, each configured to monitor a defined spatial region in the vicinity of the machine and to generate a respective sensor signal when an object is detected in the respective defined spatial region. The machine has a machine body (24, 25, 26) having an outer shell (56) and performing a rotational movement (22) about a rotation axis (20) during machine operation. The safety device includes a support structure that secures the sensors to the machine so that the sensors rotate together with the machine body during machine operation. The support structure has a support base (54) that externally surrounds the outer shell (56) of the machine body in a form that fits snugly.

Description

[Technical Field]

[0001] The present invention relates to a safety device for protecting danger zones of automatically operating machines, in particular for protecting danger zones of robots, the machine having an outer shell and a machine body that performs a rotational movement about a rotation axis during machine operation, the safety device comprising a plurality of sensors, each configured to monitor a defined spatial region in the vicinity of the machine and to generate a respective sensor signal when an object is detected in the respective defined spatial region, a support structure for fixing the plurality of sensors to the machine in such a way that the plurality of sensors rotate together with the machine body during machine operation, and an evaluation unit (14) and a control unit configured to control the rotational movement of the machine body in response to the sensor signals of the plurality of sensors. [Background technology]

[0002] Such a safety device is known from the following patent document 1.

[0003] For many years, there has been a desire and effort to protect danger zones resulting from rapid robot movements as simply and flexibly as possible to prevent accidents and injuries. In particular, it is desirable to have protection measures that allow humans to remain close to the robot and perform activities, for example, to enable collaboration between humans and robots. This approach is known as human-robot collaboration. The two-part standard EN ISO 10218 specifies requirements for collaborative robot operation. For example, if contact occurs between a robot and a human, a predetermined contact force on the human must not be exceeded. As a result, it is known that the position, force, and / or torque and / or speed at which a robot or a part of its body moves must be monitored and, if necessary, limited. This monitoring and limitation must also be guaranteed in the event of an error, i.e., fail-safe in the event of a component malfunction or software error, for example.

[0004] In the following, the term "fail-safe" is used to indicate that a component or configuration meets the requirements of category 3 according to standard EN ISO 13849-1, i.e. the requirements for the so-called performance level PL d, and / or the safety requirement level SIL3 according to standard IEC 61508 and the machine-specific sector standard EN 62061.

[0005] Patent Document 1 below discloses a safety device having a total of six presence sensors, all arranged in a U-shaped holder. Three presence sensors are arranged vertically one above the other, on each of two legs of the U-shaped holder. Each opposing sensor "looks" in an opposite direction and monitors an area to the side of the robot. The holder with the six presence sensors is arranged on a lever mechanism attached between two swivel joints of the robot. The lever mechanism moves in a direction opposite to the movement of the arm so that the holder with the presence sensors is always held in a horizontal position and the vertical alignment of the sensors is maintained.

[0006] Patent Document 2 discloses a further safety device for protecting a robot. On the one hand, this known device uses a sensor permanently attached to the floor area of ​​the robot, which may be, for example, a safety mat, a laser sensor, a camera, or an ultrasonic sensor. The permanently attached sensor is used to monitor the floor area around the robot. Additionally, the safety device of Patent Document 2 includes an additional sensor at the free end of the robot arm, in the area of ​​the so-called end effector. The additional sensor is positioned vertically above the end effector and monitors an umbrella-shaped, downward-facing sensor field of view. The additional sensor may be a laser sensor, a camera, or an ultrasonic sensor. The ground-level sensor field of view of the permanently attached sensor can be divided into several concentric subcircles, each of which is assigned a different safety level. Different safety levels may be associated with different movement speeds of the robot.

[0007] Patent Document 3 (U.S. Pat. No. 6,299,399) discloses a further safety device for protecting robots. This device includes eight ultrasonic proximity sensors permanently attached to the robot's floor area, each monitoring a defined area. The monitored area is divided into a fan-like area extending approximately 180 degrees around the robot. The safety device also includes a fence or light barrier behind the monitored area to prevent lateral access to the robot, and a rear-mounted laser scanner that monitors the fenced area behind the robot at ground level. A safety controller ensures that the robot switches to a slowed-down mode or even stops if a person moves into an area within the robot arm's current position.

[0008] In principle, the known safety devices are suitable for achieving safe operation of the robot. However, they partially impair the productivity of the robot, since its movement speed is often limited to a low speed for safety reasons, even if, upon closer inspection, this is not necessary. In addition, some known safety devices require a large number of sensors to monitor a static spatial area around the robot, or they are specially developed for a specific type of robot and cannot be used on another robot without expensive modifications. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent Application Publication No. 3 909 727 A1 [Patent Document 2] International Patent Application Publication No. WO 2018 / 145990 A1 [Patent Document 3] International Patent Application Publication No. WO 2006 / 024431 A1 Summary of the Invention [Problem to be solved by the invention]

[0010] Against this background, it is an object of the present invention to provide a safety device of the kind mentioned at the outset, which makes it possible to protect a robot or similar machine in an efficient manner, in particular one that allows high productivity of the robot without endangering people in the vicinity of the robot, and which can be used in a cost-effective manner for multiple robot types. [Means for solving the problem]

[0011] According to one aspect of the invention, a safety device of the type mentioned at the outset is provided to achieve this object, in which the support structure has a support base designed to surround the outer shell of the machine body from the outside in a snug manner.

[0012] The sensors of the novel safety device are fixedly connected to the rotating machine body and therefore change their current "looking direction" in response to the rotational movement of the machine body. The volume rotates around the axis of rotation together with the machine body and is therefore quasi-stationary relative to the moving machine body. However, the monitored volume moves relative to a fixed point in the vicinity of the machine. This distinguishes the novel safety device from concepts that use fixed sensors to monitor static volume areas. The novel safety device makes it possible to get by with a relatively small number of sensors, which contributes to efficient and cost-effective implementation.

[0013] Furthermore, the sensor is mechanically connected to a moving machine body via a novel support structure. The machine is in particular a robot with serial kinematics, in particular an articulated arm robot or a SCARA robot, and the moving machine body is in a preferred embodiment a rotatable arm of the robot. The serial kinematics comprises a first rotation axis and a further rotation axis or swivel joint, via which the arm parts are connected so that they can rotate or pivot (relative to each other).

[0014] In a preferred embodiment of the novel safety device, the machine body, whose shell is surrounded by the support base in a form-fitting manner, is the robot's first axis of rotation (i.e., the axis of rotation that connects the robot to a stationary base). Mounting the support structure at or on the first axis of rotation has the advantage that the payload (i.e., the load that the robot can carry and handle) is only slightly reduced by the support structure and sensors, if any. In a preferred embodiment, the support base surrounds the vertical axis of rotation shell (i.e., the machine body that allows the machine to rotate about the vertical axis of rotation).

[0015] The machine body shell is the exterior of the housing, i.e., the outer covering that separates the machine body from its surroundings. The support base preferably matches the machine body shell and is placed on the machine body shell. The support base "rides" on the machine body while it rotates, so to speak. In a preferred embodiment, the support base is composed of several parts that surround the machine body shell like a clamp. An advantage of this embodiment is that the support structure with sensors can be very easily and cost-effectively adapted to a variety of different robot types and robot sizes from different manufacturers. In a preferred embodiment, it is sufficient to use 3D data of the shell (e.g., CAD data or 3D data captured by a 3D scanner) to build a support base that matches the shell.

[0016] In a preferred embodiment, the support structure is also made up of several parts and comprises, in addition to the support base, further elements on which the sensors are or may be attached, in which case it is sufficient to construct a matching support base in order to fit the support structure to different robot types or different robot sizes.

[0017] Preferably, each of the aforementioned sensors is a radar sensor, since radar radiation, which has electromagnetic waves from the microwave range, is highly robust against fog, dust, dirt, flying sparks, or rain. In a preferred embodiment, the radar sensor operates at an operating frequency in the range of 10 GHz to 80 GHz, preferably in the range of 20 GHz to 30 GHz, or in the range of 60 GHz to 70 GHz. These frequency ranges allow fast and accurate detection of impacting objects, even when the aforementioned environmental factors impair "clear visibility." This makes these sensors ideal for harsh industrial environments. Alternatively, the aforementioned sensors may in principle be lidar sensors, cameras, or ultrasonic sensors operating with light from the visible and / or infrared wavelength ranges. A combination of different sensor principles is also conceivable for multiple sensors.

[0018] The novel configuration can be used very universally and cost-effectively for a variety of machines. The co-rotating sensors allow for efficient protection and high productivity, especially in the case of human-robot cooperation. Thus, the above objectives are fully achieved.

[0019] In a preferred refinement, the support base is designed to accommodate the machine body in a pot-like manner.

[0020] In this refinement, the support base defines an interior space that accommodates, to some extent, the outer shell of the machine body when the support structure is attached to the machine. In preferred embodiments, the interior space is substantially cylindrical. Moreover, in some embodiments, the interior space need only accommodate more than 50% of the outer shell, and preferably more than 75% of the outer shell of the moving machine body. This refinement allows for a very stable attachment of the support base to the outer shell of the machine body. The substantially cylindrical interior space can be used for a variety of robot types and sizes, thus allowing for cost-effective implementation and adaptation. To save material and weight, the pot-shaped receptacle may have openings or holes in its side walls. That is, the "pot" may be completely closed everywhere, but this is not required. A completely enclosed interior space is preferred in some embodiments to prevent debris or other contaminants from machining the workpiece from collecting where the support base is attached to the machine body.

[0021] In a further refinement, the support base comprises a first half-shell and a second half-shell, which together are designed to surround the outer shell in a clamp-like manner.

[0022] In this refinement, the support base is essentially two parts: in some preferred embodiments, half shells are bolted together. This refinement allows a very simple and stable assembly of the support base to the machine body.

[0023] In a further refinement, the support base is designed to surround the outer shell of the machine body in two mutually different, non-parallel planes.

[0024] Particularly in robots with serial kinematics, such as articulated arm robots, the machine body surrounded by a support base is often followed by further arms which have a transverse, and often perpendicular, orientation to the main direction of the machine body or to its axis of rotation. This refinement makes it possible to fix the support base to the machine body in a particularly stable manner, especially when non-parallel planes are perpendicular to the axis of rotation of the machine body and the further arms.

[0025] In a further refinement, the support structure comprises a beam fixed to the support base, and at least one sensor of the plurality of sensors is held via the beam at a distance from the support base.

[0026] This refinement makes it easy to arrange one or more sensors at a freely selectable height or distance from the moving parts of the machine body, for example, one or more sensors can be arranged very easily in such a way that their field of view is not impaired or only slightly impaired by other machine parts in this refinement.

[0027] In some preferred embodiments, the sensor configuration comprises a plurality of sensors forming a first sensor group and a second sensor group, where the sensors of the first sensor group define a first sensor surface during machine operation, and the sensors of the second sensor group define a second sensor surface during machine operation, with the first sensor surface being remote from the second sensor surface. For example, the first sensor surface may be located vertically below the second sensor surface. Such an arrangement of multiple sensors at separate levels can be implemented very easily and cost-effectively with this refinement and allows suitable comprehensive protection of a moving machine body with a small number of sensors. In preferred embodiments, the first level is close to the floor. That is, the monitored spatial area of ​​the sensors of the first sensor group extends downward to the floor. They, so to speak, rest on the floor.

[0028] The sensors of the first sensor group preferably have a main viewing direction that is essentially perpendicular to the rotation axis. In contrast, in a preferred embodiment, the main viewing direction of the sensors of the second sensor group extends obliquely (in particular obliquely to the floor) with respect to the main viewing direction of the sensors of the first sensor group. The sensors of the first sensor group can be used to efficiently monitor a spatial area around the moving machine body, but without the moving machine body itself. On the other hand, the sensors of the second sensor group can be used to monitor a spatial area radially in front of the moving machine body, as it were, from above diagonally, without the machine body obscuring the line of sight of the sensors of the second sensor group.

[0029] In a further refinement, at least one sensor of the plurality of sensors is held by the support base.

[0030] This refinement allows a very simple installation of at least one sensor in the direct vicinity of the moving machine body, which can therefore be very effectively protected.

[0031] In some embodiments, the sensor device has three sensors covering a comprehensive field of view of approximately 270 degrees. In particular, the plurality of sensors may include a first sensor monitoring a first defined spatial region and generating a first sensor signal when an object is detected in the first spatial region. Furthermore, the plurality of sensors may include a second sensor monitoring a second defined spatial region and generating a second sensor signal when an object is detected in the second spatial region, and the plurality of sensors may include a third sensor monitoring a third defined spatial region and generating a third sensor signal when an object is detected in the third spatial region. The first spatial region, the second spatial region, and the third spatial region are distinct from one another, the first and second spatial regions are adjacent to one another during machine operation, and the second and third spatial regions are adjacent to one another during machine operation. Preferably, the first, second and third spatial regions are divided around the axis of rotation during operation of the machine such that when the machine body rotates, the first, second and third spatial regions follow each other in the current direction of rotation. The sensors preferably form a first sensor group close to the ground and are able to monitor an azimuthal spatial region excluding the machine body so that the field of view of these sensors is clear.

[0032] Preferably, the monitored spatial regions are located next to each other in the rotational plane of the machine body and follow each other as the machine body rotates. The rotational plane is essentially perpendicular to the rotation axis, in particular perpendicular to the rotation axis. This means that the monitored spatial regions move quickly through the same spatial section one after the other along the current direction of rotation. The respective trailing and leading spatial regions allow for high productivity, since a slow creep speed or a safety stop is only activated if an object to be protected, in particular a person or a part of a person, is directly in the range of motion of the moving machine body. Due to the arrangement of the moving spatial regions, the movement path of the machine body can be divided into critical and less critical spatial regions in a very simple and cost-effective manner. The safety distance at which the safety function is activated can be reduced compared to known safety devices. Unnecessary creeping movements at slow speeds can be minimized. At the same time, the rotating spatial region means that a safety stop or creep speed can be activated whenever a person is directly in front of the machine body in the current direction of rotation.

[0033] In preferred embodiments, the sensors each monitor a cylindrical region of space extending from the respective sensor over an azimuthal opening angle greater than the elevation opening angle. The azimuthal opening angle preferably lies in the plane of rotation of the respective sensor. The elevation opening angle is preferably defined parallel to the axis of rotation. In some preferred embodiments, the azimuthal opening angle is in the range between 20 degrees and 120 degrees, and the elevation opening angle is in the range between 10 degrees and 300 degrees. Adjacent regions of space may overlap at their respective boundaries. Preferably, the angular range over which adjacent regions of space overlap is small compared to their respective opening angles. In preferred embodiments, the azimuthal overlap angle of two adjacent regions of space is at most 20%, preferably at most 10%, of their respective azimuthal opening angles. Thus, each of the three sensors monitors more than half of the region of space exclusively assigned to it. Preferably, each of the three sensors monitors more than 75% of the region of space exclusively assigned to it.

[0034] This improvement advantageously contributes to maximizing machine productivity by reducing or even avoiding unnecessary false stops and creeping of the machine and by activating safety functions in the form of novel safety device stops and creeping movements only when necessary.

[0035] In a further refinement, the support structure comprises a friction-enhancing intermediate element intended to be arranged between the support base and the shell.

[0036] The intermediate element may be an insert made of an elastic material such as rubber or sponge rubber, or a fabric-like material such as a felt material. The intermediate element may be arranged over a large area in the interior space of the support base, in particular covering more than 50% of the contact surface between the outer shell of the machine body and the support base. Alternatively, the intermediate element may comprise a plurality of intermediate elements arranged at several separate contact points. In some embodiments, the intermediate element may be arranged around the machine body as a loose insert before the support base is assembled to the machine body. In other embodiments, the intermediate element may be attached to the contact surface of the support base before assembly, for example by an adhesive connection. The friction-enhancing intermediate element improves the contact friction between the outer shell of the machine body and the support base compared to an assembly without the intermediate element. This refinement advantageously contributes to a stable, torsion-resistant connection between the support base and the outer shell of the machine body by achieving an (improved) frictional connection in addition to a snug fit. In a preferred embodiment, the outer shell of the machine body is suction-fitted to the support base with the aid of an intermediate element.

[0037] In a further refinement, the support base is adapted to be attached to the machine body in a non-destructive and removable manner.

[0038] This refinement is advantageous because it facilitates the maintenance and, if necessary, repair of the machine in the area of ​​the rotating shaft. Furthermore, the machine can be very easily retrofitted, for example if new safety devices are required for a new use of the machine.

[0039] In a further refinement, the evaluation and control unit comprises a first fail-safe evaluation and control unit and a second non-fail-safe control unit, the second control unit controlling the movement of the machine body in response to an operating program and in response to a binary enable signal from the first evaluation and control unit, the first evaluation and control unit generating the binary enable signal in response to the plurality of sensors.

[0040] As mentioned above, "fail-safe" in this case means that the first evaluation unit and control unit meet the requirements of Category 3, i.e., the so-called performance level PL d according to standard EN ISO 13849-1 and / or the safety integrity level SIL 3 according to IEC 61508 or the machine-specific standard EN 62061. In contrast, the second control unit does not meet these requirements. It is therefore a so-called standard control unit, which essentially controls the desired operating sequence of the machine according to an operating program. This modification enables the safe and productive operation of the machine in a cost-effective manner. In particular, this modification allows the retrofitting of new safety devices to machines that were previously protected differently, thus achieving increased productivity without extensive changes to the desired operating sequence.

[0041] Preferably, the first evaluation unit and the control unit generate two mutually redundant binary enable signals, each of which may have a high signal level (on state) or a low signal level (off state). The high signal level indicates, in particular, that the preceding first spatial region in the direction of rotation is free. The second control unit can then rotate the machine body at a high rotational speed if this is intended in the desired operating sequence. Thus, the high signal level is a fail-safe enable signal for high rotational speeds. On the other hand, the low signal level indicates that the enable signal is no longer present, which means that the second control unit can only move the machine body at a limited, slow rotational speed. Preferably, the first evaluation unit and the control unit each generate two redundant binary enable signals with a test pulse (i.e., a defined pulse from a high signal level to a low signal level). The test pulse allows for detecting stuck-at-high errors in the output circuits of the first evaluation unit and the control unit. Preferably, the test pulses of the two mutually redundant binary enable signals are out of phase with one another, which allows for good cross-circuit detection. This refinement allows for hardwired handshake between the first evaluation and control unit and the non-fail-safe second control unit.

[0042] In a further refinement, the evaluation unit 14 and the control unit are arranged to limit the rotation speed of the machine body about the rotation axis in a fail-safe manner depending on the sensor signal from the sensor.

[0043] In this refinement, the machine body is moved at a reduced rotational speed compared to unimpeded operation, the so-called creep speed of the machine body beneficially contributing to maintaining the productivity of the machine, albeit at a slower movement due to the risk of collision in the preceding spatial region in the direction of rotation, when an object is detected in the respective preceding spatial region in the direction of rotation.

[0044] In a further refinement, at least one sensor of the plurality of sensors has a first sensing area and a separate second sensing area within the associated spatial region, the first sensing area being closer to the sensor than the second sensing area, the sensor generating a separate sensor signal for each of the two sensing areas, and the evaluation unit 14 and the control unit being configured to control the rotation of the machine body depending on the separate sensor signals.

[0045] In this refinement, the spatial region of at least one region is divided into two different distance ranges. Preferably, all sensors of the plurality of sensors have such a first and a separate second detection zone within their respective monitored spatial region. This refinement allows the evaluation unit 14 and the control unit to easily trigger different reactions depending on the distance of an object in the monitored spatial region. Preferably, the evaluation unit 14 and the control unit can generate an optical and / or acoustic warning signal at a larger distance to prevent a person from moving further into the working area of ​​the machine. On the other hand, the evaluation unit 14 and the control unit can immediately reduce the speed of movement of the machine body and / or stop the movement of the machine body when an object is detected at a shorter distance. Alternatively, the evaluation unit 14 and the control unit can reduce the rotational speed of the machine body as soon as the warning signal is generated. This refinement helps to achieve high productivity along with safe operation of the machine.

[0046] It is understood that the features mentioned above and those that will be described below can be used not only in the combination indicated in each case, but also in other combinations or alone, without departing from the scope of the invention.

[0047] Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. [Brief explanation of the drawings]

[0048] [Figure 1] 1 shows an embodiment of a novel safety device for an articulated robot. [Figure 2] 2 is a schematic diagram of the safety device of FIG. 1 showing three monitored spatial regions; [Figure 3] 2 shows the safety device of FIG. 1, schematically illustrating three further monitored spatial regions; [Figure 4] 2 shows the articulated arm robot of FIG. 1 with a half-shell of the support base of the safety device of FIG. 1; [Figure 5] 2 shows the support base of the safety device of FIG. 1 having two half shells; DETAILED DESCRIPTION OF THE INVENTION

[0049] In Figure 1, an embodiment of the novel safety device is indicated generally by the reference number 10. In this embodiment, the safety device 10 comprises six radar sensors 12-1, 12-2, 12-3, 12-4, 12-5 and 12-6, hereinafter collectively referred to by the reference number 12, and a fail-safe evaluation unit 14 and a control unit, which in this case are connected to the radar sensors 12 via a serial bus connection 16 (shown here only schematically). In preferred embodiments, the serial bus connection 16 is based on the CAN bus protocol, which allows for highly efficient data transmission between the serially connected sensors and the evaluation unit 14 and control unit. In some embodiments, the evaluation unit 14 and control unit comprise a fail-safe controller called PNOZmulti 2, which is commercially available from the applicant Pilz GmbH & Co KG, 73760 Ostfildern, Germany.

[0050] The sensor 12 is in this case located on the articulated arm robot 18 and is therefore able to rotate together with the robot 18 about its axis of rotation 20. In this case, the axis of rotation 20 is a first of several axes of rotation of the robot 18, which here extends perpendicular to the floor or foundation on which the robot 18 is placed with its base.

[0051] In some embodiments, the robot 18 is capable of pick-and-place operations, whereby it rotates in alternating directions about its axis of rotation 20. Each current rotation direction is indicated by reference numeral 22. As is known to those skilled in the art, the robot 18 has multiple arms rotatably connected to one another via swivel joints. Some of these arms are indicated here by reference numerals 24, 25, and 26 (see also FIG. 4). The rotation of the arms 24, 25, and 26 relative to one another and the rotation of the robot 18 about its axis of rotation 20 are controlled here by a non-failsafe control unit 28. The control unit 28 may be a conventional robot controller typically provided by the manufacturer of the robot 18 and delivered with the robot. The control unit 28 controls the desired operating sequence of the robot 18 in a manner known per se according to an operating program typically loaded on the control unit 28. In some preferred embodiments, the evaluation unit 14 and the control unit, as well as the robot's operating control unit 28, may communicate with each other via a bidirectional connection 29. In some embodiments, the connection 29 may comprise a fail-safe bus connection, for example based on a fail-safe Ethernet protocol. In a preferred embodiment, the connection 29 comprises two or more redundant binary enable signals 29a, 29b (so-called OSSD signals), such as those provided by the applicant's fail-safe miniature controller PNOZmulti 2.

[0052] Depending on the operating situation, the movable arm sections 24, 26 form a contour 30 that is aligned with the current rotation direction 22. This contour may exert a large contact force on a person or object (not shown) if it comes into contact with the person or object within the rotation range of the robot 18. To prevent this, each sensor 12 monitors a predetermined assigned spatial region 32. In FIG. 1, a first spatial region 32-1, a second spatial region 32-2, and a third spatial region 32-3 are indicated by dashed lines. For example, the first sensor 12-1 monitors the first spatial region 32-1, the second sensor 12-2 monitors the second spatial region 32-2, and the third sensor 12-3 monitors the third spatial region 32-3. The three spatial regions 32-1, 32-2 and 32-3 are adjacent to one another, and the sensors 12-1, 12-2 and 12-3 define a plane (level) 34, which in this case is close to the ground and is mostly parallel to the ground.

[0053] FIG. 2 shows the spatial regions 32-1, 32-2, and 32-3 in a perspective view. As can be seen from FIG. 2, the monitored spatial regions 32-1, 32-2, and 32-3 overlap at a certain distance in adjacent areas, so that the three sensors 12-1, 12-2, and 12-3 together cover a continuous rotation angle range 36 that surrounds the robot 18 on three sides. In the illustrated embodiment, the spatial regions 32-1, 32-2, and 32-3 together cover a rotation angle range 36 of approximately 270 degrees. In this case, each of the three sensors 12-1, 12-2, and 12-3 monitors its assigned spatial region 32-1, 32-2, and 32-3, and each of these regions covers approximately one-third of the rotation angle range 36. The jointly monitored rotation angle range 36 extends in the azimuth direction and does not include the robot 18. Thus, in this embodiment, arms 25, 26 (and more generally robot 18) do not generate radar reflections that can be detected by sensors 12-1, 12-2 and 12-3.

[0054] Dividing the azimuth spatial region 36 into three largely equal-sized monitored spatial regions 32-1, 32-2, 32-3 has proven to be very suitable in some embodiments for monitoring the rotational angular range of a robot 18 with a small number of sensors in a manner that allows the robot 18 to operate at a high level of productivity. Preferably, the fail-safe evaluation unit 14 and control unit generate the above-mentioned enable signal if the previous spatial region in the current direction of rotation is "free" (i.e., the assigned sensor does not detect any potential collision object in the spatial region it is monitoring). Thus, for example, if the robot 18 is to rotate clockwise in a specified operating situation, the evaluation unit 14 and control unit generate the above-mentioned enable signal if the spatial region 32-1 is free (i.e., the first sensor 12-1 does not detect any collision object in the spatial region 32-1). Conversely, the evaluation unit 14 and the control unit will generate the aforementioned enable signal if the robot 18 is to rotate counterclockwise in another operating situation and if the spatial region 32-3 is free (i.e. if the third sensor 12-3 does not detect a collision object in the spatial region 32-3). Notwithstanding this embodiment, in further embodiments in which the machine bodies 24, 26 pass through a rotation angle range of less than 300 degrees during their intended operation, it is preferred if the safety device 10 monitors said rotation angle range in three, four or up to five spatial regions which together cover the entire rotation angle range.

[0055] As can also be seen from Figure 2, each of the monitored spatial regions 32-1, 32-2, 32-3 in this case has a shape similar to a slice of pie or cake (i.e., corresponding to a sector of a circle in plan view), but is limited in height, i.e., the azimuthal opening angle 38, shown for spatial region 32-3 in Figure 1 by reference number 38, is made larger in height than the opening angle 40.

[0056] In a preferred embodiment, some or even all of the sensors 12-1 through 12-6 have a first sensing area 42 and a separate second sensing area 44 within their respective monitored spatial regions (shown in FIG. 1 using the example of first area 12-1). The first sensing area 42 is located closer to the respective sensor than the second sensing area 44.

[0057] Each sensor generates a separate sensor signal for each of the two detection zones 42, 44, and the evaluation unit 14 and the control unit 28 are configured to control the rotation of the machine body 24, 26 in response to the separate sensor signals. The separate detection zones 42, 44 make it possible to take into account the current distance of a potential collision object to the robot 18 when controlling the rotational movement. For example, a visual and / or acoustic warning signal can only be triggered by the evaluation unit 14 and the control unit 28 if an object is detected in the second, more distant detection zone 44, while only detection of an object in the first detection zone 42 triggers a reduction in the current rotational speed or even an emergency stop. In a further embodiment, the evaluation unit 14 and the control unit 28 can be configured to limit the current rotational speed of the machine body or reduce it to a creeping speed in the event of detection of an object in the more distant detection zone 44, while detection of an object in the closer detection zone 42 always triggers an emergency stop. In principle, the monitored spatial region may also have more than two separate detection areas spaced apart, whereby the evaluation unit 14 and the control unit 28 are configured to control the rotational movement of the machine body depending on the azimuthal position of the object (detected by the respective spatial region or sensor signal) and the respective distance (detected by the respective detection area).

[0058] In the embodiment shown in FIG. 1, the safety device 10 has two sensor groups with a total of six sensors. Sensors 12-1, 12-2, and 12-3 form the first group and define a level 34 close to the ground. Sensors 12-4, 12-5, and 12-6 form the second sensor group, located on a platform 50 above sensors 12-1, 12-2, and 12-3. Platform 50 is supported by a support base 54 via a beam 52. Sensors 12-4, 12-5, and 12-6 in this case define a plane (level) 46, which is located vertically above plane (level) 34. In this embodiment, sensor 12-6 is even located slightly above plane 46.

[0059] In the illustrated embodiment, beam 52 is a telescoping beam with a variably adjustable beam length, thereby allowing adjustment of the distance of platform 50 from support base 54. Advantageously, in this manner, the distance between sensor level 34 and sensor level 46 can be adjusted depending on the height of robot 18 so that sensors 12-4, 12-5, and 12-6 have a largely unobstructed field of view beyond robot 18 and its arms.

[0060] 1 and 3, the sensors 12-4, 12-5, 12-6 of the second sensor group jointly monitor an additional azimuthal spatial region 48 that, from the perspective of the sensors 12-4, 12-5, 12-6, extends behind the robot 18 or its arm. Thus, the spatial region monitored by the sensors 12-4, 12-5, 12-6 notably covers the gaps left by the azimuthal spatial region 36, as shown in FIG.

[0061] 4 shows another robot 18 without the safety device 10 but with a half-shell 54a of a support base 54 on the outer shell 56 of the machine body 24. Otherwise, the same reference numerals refer to the same elements as before.

[0062] 5 shows a half shell 54a and a second half shell 54b, which can be placed as separate parts on the outer shell 56 of the machine body 24 from the outside in order to assemble the support base 54 to the machine body 24. As can be seen from FIGS. 4 and 5, the half shells 54a, 54b in this embodiment together form an interior space 58 that can almost completely accommodate the outer shell 56 of the machine body 24.

[0063] In some preferred embodiments, a friction-enhancing, particularly rubber-like, intermediate element 60 can be placed in the inner space 58 of the support base 54, which can "pad" the inner space 58 to some extent. In some embodiments, the inner space 58 is essentially complementary to the outer shell 56 of the machine body 24, so that the outer shell 56 is received in the inner space 58 in a snug and precise-fitting manner. The optional intermediate element 60 can preferably compensate for small deviations between the actual shape of the inner space 58 and the actual shape of the outer shell 56, contributing to a particularly torsion-resistant and stable connection.

[0064] As can be seen particularly in Figure 5, the support base 54 surrounds the outer shell 56 of the machine body 24 in this embodiment on two different sides 62, 64. Each of the two half shells 54a, 54b has a substantially semicircular edge 66, 68. The semicircular edge 66 of the half shells 54a, 54b is located in a plane 62 that is substantially perpendicular to the rotation axis 20 of the machine body 24. In contrast, the semicircular edge 68 of the half shells 54a, 54b is located in a plane 64 that is substantially parallel to the rotation axis 20 of the machine body 24. In the embodiment shown here, each of the half shells 54a, 54b has a flange-like protrusion 70 that allows the two half shells 54a, 54b to be screwed together after the half shells 54a, 54b have been placed on the outer shell 56 of the machine body 24 from the outside.

[0065] Reference number 72 in Figure 5 indicates an assembly surface where one of the sensors 12 can be mounted directly on the support base 54 for rotation together with the machine body 24 during machine operation. Reference number 74 indicates a further interior space formed by the half shells 54a, 54b where the beam 52 can be inserted.

Claims

1. A safety device for protecting danger zones of an automatically operating machine, in particular a robot (18), comprising: the machine comprises a machine body (24, 25, 26) having an outer shell (56) and performing a rotational movement (22) about an axis of rotation (20) during operation of the machine; The safety device comprises a plurality of sensors (12-1 to 12-6), each configured to monitor a defined spatial region (32-1, 32-2, 32-3) in the vicinity of the machine and to generate a respective sensor signal when an object is detected in the respective defined spatial region (32-1, 32-2, 32-3); a support structure (50, 52, 54) for fixing the plurality of sensors to the machine in such a manner that the plurality of sensors (12-1 to 12-6) rotate together with the machine body during operation of the machine; an evaluation unit (14) and a control unit (28) configured to control the rotational movement of the machine body in response to the sensor signals of the plurality of sensors (12-1 to 12-6); A safety device, wherein the support structure (50, 52, 54) has a support base (54) designed to surround the outer shell (56) of the machine body from the outside in a snug manner.

2. 2. A safety device according to claim 1, wherein the support base (54) defines an interior space (58) designed to accommodate the machine body in a pot-like manner.

3. 2. The safety device of claim 1, wherein the support base (54) has a first half shell (54a) and a second half shell (54b) that are designed to surround the outer shell (56) in a clamp-like manner.

4. 4. A safety device according to any one of claims 1 to 3, wherein the support base (54) is designed to surround the outer shell (56) of the machine body along two different, non-parallel planes (62, 64).

5. 4. The safety device according to claim 1, wherein the support structure comprises a beam (52) fixed to the support base (54), and at least one sensor (12-4, 12-5, 12-6) of the plurality of sensors is held at a distance from the support base (54) via the beam (52).

6. The safety device according to any one of claims 1 to 3, wherein at least one sensor (12-1, 12-2, 12-3) of the plurality of sensors is held by the support base (54).

7. 4. A safety device according to any one of claims 1 to 3, wherein the support structure comprises a friction-increasing intermediate element (60) intended to be placed between the support base (54) and the outer shell (56).

8. A safety device according to any one of claims 1 to 3, wherein the support base (54) is configured to be attached to the machine body in a non-destructive and removable manner.

9. The evaluation unit (14) and the control unit comprise a first fail-safe evaluation unit and control unit (14) and a second non-fail-safe control unit (28), the second control unit (28) controls the movement of the machine body in response to a running program and in response to binary enable signals (29a, 29b) from the first evaluation unit and the control unit (14); 2. The safety device according to claim 1, wherein the first evaluation and control unit (14) generates the binary enable signal (29a, 29b) in response to the plurality of sensor signals.

10. 10. An automatically operating machine having a machine body that performs a rotational movement (22) about a rotation axis (20) during operation of the machine, the machine having a safety device (10) according to claim 1.

11. 11. The autonomously operated machine of claim 10, wherein the machine body is a robot arm of a robot having serial kinematics.

12. 12. The autonomously operated machine of claim 11, wherein the serial kinematics comprises a first rotation axis (20) and a further rotation axis (21), the first rotation axis (20) connecting the robot arm portion (24) to a stationary base.

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