Method and system for controlling access to an environment

Abstract

Methods and systems are provided for controlling access to an environment. A set of one or more radar sensors (2) controls access of an object (200) to an environment (100) having a hazardous device (110). The radar sensor (2) initiates detection in a first region of interest (3) in an access path (130) to the environment (100). Upon detection of the object (200), the hazard device (110) is commanded to take a first security measure, interrupt the detection in the first region of interest (3), and start the detection at a second region of interest (4) arranged more internally than the first region of interest (4). When an object (200) is detected in the second region of interest (4), a second security measure is activated. Alternatively, if there is no object (200) in the second region of interest (4) within a predetermined time, the detection in the second region of interest (4) is interrupted and the detection in the first region of interest (3) is restarted.

Description

Technical Field

[0001] The invention was developed in the technical field of radar detection for controlling access to an environment, in particular an environment in which hazardous installations are present, for example in the industrial sector. Background Art

[0002] It is well known in the industrial field to use sensors to detect workers accessing areas where there are hazardous devices, such as machines with moving parts, etc. Two (or more) regions of interest are usually defined, one extending further from the machine, which causes the machine to slow down when an object intrudes, and another closer to the machine, which causes the machine to stop.

[0003] Sensors used for this purpose include photoelectric barriers, laser scanners and radar. Radar sensors have advantages in terms of flexibility and robustness in harsh environments, but they pose difficulties in generating regions of interest of small size (depending on the shape of the region of interest).

[0004] In particular, the simplest region of interest for which a radar sensor can be defined is a circular sector, which is identified by a distance radius from the sensor and the opening angle of the sector. However, usually a single circular sector is not sufficient to adequately monitor all possible machine access trajectories. Therefore, several radar sensors, appropriately positioned and oriented, are usually installed, which together identify the desired region of interest. These regions become particularly complex when the access path to the machine is not laterally delimited, so that the possibility of access from several directions is envisaged.

[0005] Alternatively or additionally, with a greater computational burden, each radar sensor may cover an area not given by a single circular sector, but by the union of a number of circular sectors centered on the same radar sensor. Thus, a single radar sensor or a small number of radar sensors may cover an area of ​​interest having an approximately rectangular plane (more versatile from the point of view of the final shape of the monitored area).

[0006] When the outermost zone for decelerating the machine and the innermost zone for stopping must be distinguished, each radar sensor in the overall arrangement can define two corresponding different regions of interest. In this case, however, it is customary for each such region to be identified by a single circular sector or circular crown shape.

[0007] In fact, the simultaneous coverage of two zones by the same radar sensor constitutes a computational burden that is acceptable only when the shape of the zone is simple. On the contrary, when the radar sensor covers more complex zones (such as approximately rectangular zones, etc.), the simultaneous coverage of two zones with complex shapes requires the radar sensor to spend too much time to perform all the necessary processing, which often results in unacceptable delays in signaling objects and increases the computational capacity of the radar sensor, thereby increasing its cost. Summary of the invention

[0008] The object of the present invention is to address the disadvantages of the prior art and in particular to allow a single radar sensor to identify areas of interest, such as to trigger different safety measures etc., without unduly increasing the computational burden, thereby allowing the use of zones with more complex shapes for each sensor for a single circular sector.

[0009] These and other objects are achieved by a method and a system for controlling access to an environment according to any of the appended claims.

[0010] According to the invention, at least one radar sensor detects the access of an object to a first area of ​​interest in an access path to an area where there are devices, such as machines with movable parts, etc. When the access of an object to the first area of ​​interest is detected, a first safety measure is triggered, such as a deceleration of the machine, etc. Furthermore, the detection in the first area of ​​interest is interrupted, and the detection of the object access to a second area of ​​interest in the access path is started.

[0011] The second area is closer to the potentially dangerous device, so as to be encountered by an object approaching the device after the first area. When an object is detected in the second area, a second safety measure is triggered, such as shutting down the dangerous device.

[0012] If there is a lack of an object room in the second area within a predetermined time, the radar sensor interrupts detection in the second area and resumes detection in the first area.

[0013] Advantageously, the radar sensor, although it has a first region of interest and a second region of interest in its memory, does not verify the presence of an object in both regions of interest in the same detection cycle, but only in one of them. In particular, at a first moment, for some cycles, the radar performs processing to determine the presence of an object only in the first region, but not in the second region, and then for other cycles only determines whether an object is in the second region, but not in the first region. The additional processing of commanding the sensor to switch between the two regions of interest is inexpensive. As a result, the time used for processing the individual cycles is limited, and there is no significant delay in signaling an object, even when using complex regions of interest.

[0014] Furthermore, although the deceleration and stop zones are not active simultaneously, this does not significantly reduce the safety of the system. In fact, by arranging the zones of interest so that an object approaching a hazardous installation encounters the deceleration zone before the stop zone, the activation of the safety measure occurs at a moment equivalent to the case where both zones always operate simultaneously (except for a minimum time delay due to the change of mode, which can be compensated by slightly increasing the size of the deceleration zone).

[0015] Those skilled in the art will recognize other features and advantages of the present invention from the following detailed description of exemplary embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to better understand the following detailed description, some embodiments of the present invention are shown in the accompanying drawings, in which:

[0017] - Figure 1 An example of a system for controlling access to an environment according to an embodiment of the present invention is shown.

[0018] - Figure 2 shows an example of a radar area monitored by a radar sensor that may be used in a system according to some embodiments of the present invention,

[0019] - Figure 3 , Figure 4 and Figure 5 Another embodiment of a system for controlling access to an environment in three different detection modes is shown. DETAILED DESCRIPTION

[0020] A system for controlling access to an environment is generally indicated by numeral 1. The system 1 comprises one or more radar sensors 2 and a control system (not illustrated). The control system may comprise one or more controllers, which may or may not be partially or fully integrated in the radar sensor 2.

[0021] The environment 100 to be monitored for access is an environment in which a hazardous device 110 exists. The hazardous device 110 may be a machine having one or more parts that move automatically. In other embodiments, the hazardous device may be a device having exposed active electrical components or other sources of danger, without necessarily including movable parts.

[0022] The environment 100 may be bounded on one or more sides by one or more barriers 120 (e.g., a fence section such as a wire mesh or a wall of a room, etc.). The environment 100 may be accessed from an outside area by an operator along one or more access paths 130 leading to the hazardous device 110. Each access path 130 passes through at least one side of the environment 100 that is not enclosed by a barrier 120. In some embodiments, the environment 100 of the hazardous device 110 is not bounded by any barrier 120, thereby allowing access to the environment 100 from all sides from an outside area.

[0023] Each radar sensor 2 of the system 1 is positioned along an access path 130 to the environment 100. For example, the radar sensor 2 may be positioned in the access path 130, or at a side or end of the access path 130, or near the access path 130.

[0024] In the first detection mode, the control system controls each radar sensor 2 to start cyclically detecting a visit of an object 200 to a first region of interest 3 occupying at least a portion of the access path 130 .

[0025] Preferably, in the presence of more than one radar sensor 2, in the first detection mode, the radar sensors 2 are configured to detect together the access of the object 200 to the first region of interest 3. In other words, the first region of interest 3 may consist of a union of a plurality of first radar regions 31 monitored by different radar sensors 2, each radar sensor 2 detecting the access of the object 200 to the respective first radar region 31. The first radar regions 31 typically overlap at least partially with one another. Optionally, not all radar sensors 2 are activated in the first mode, but it is conceivable that some radar sensors 2 are activated only in other modes, as described below.

[0026] In the case of a single radar sensor 2 , first region of interest 3 coincides with first radar region 31 of single radar sensor 2 .

[0027] In general, the first region of interest 3 is shaped to occupy all sides of the environment 100 that are not surrounded by the barrier 120. In other words, the first region of interest 3 is interposed between the environment 100 and the outside area, so that objects 200 from the outside area cannot reach the environment 100 without passing through the first region of interest 3.

[0028] The first region of interest 3 may also optionally extend into the environment 100, but preferably the first region of interest 3 does not cover the hazardous device 110. This is advantageous in the case of hazardous devices 110 having movable parts, since otherwise the movable parts may be detected by the radar sensor 2, thereby causing a false alarm. In a less preferred alternative, the radar sensor 2 may envisage appropriate processing of a known type to discern and ignore specific types of objects 200 (such as the movable parts in question, etc.), so that the hazardous device 110 does not need to be excluded from the first region of interest 3.

[0029] In the case where no object 200 is detected, the first detection mode remains substantially active. Figure 3 As shown, when access of the object 200 is detected in the first region of interest 3, the first detection mode is interrupted and the second detection mode is started.

[0030] Furthermore, once again, upon detection of access of the object 200 in the first area of ​​interest 3, the control system commands the hazardous device 110 to activate a first safety measure. Preferably, the first safety measure comprises slowing down the movement speed of at least one movable part of the hazardous device 110. However, other safety measures may be envisaged by a person skilled in the art, both in the case of a machine with movable parts and in the case of a hazardous device 110 without movable parts.

[0031] The command of the first safety measure and the transition from the first detection mode to the second detection mode are preferably substantially simultaneous, but in other embodiments the two events may occur consecutively, such as first the command of the first safety measure and then the transition from the first detection mode to the second detection mode.

[0032] With the transition from the first detection mode to the second detection mode, the set of radar sensors 2 is controlled to interrupt the detection of access to the object 200 in the first region of interest 3. Furthermore, in the second detection mode, the set of radar sensors 2 is controlled to start cyclically detecting the access of the object 200 to the second region of interest 4 (e.g., the region of interest that occupies at least a portion of the access path 130) in a loop. Figure 4 Detection shown).

[0033] It should be noted that in the first detection mode, only the first region of interest 3 is active and the second region of interest 4 is inactive, and vice versa, in the second detection mode, only the second region of interest 4 is active and the first region of interest 3 is inactive. Figure 1, the first region of interest 3 and the second region of interest 4 are shown together only to facilitate comparison of their shapes. Therefore, when controlled to detect that an object 200 accesses the first region of interest 3, the set of radar sensors 2 is configured not to distinguish whether each object 200 is inside or outside the second region of interest 4. Similarly, when controlled to detect that an object 200 accesses the second region of interest 4, the radar sensor group 2 is configured not to distinguish whether each object 200 is inside or outside the first region of interest 3.

[0034] Advantageously, each radar sensor 2 does not monitor first radar area 31 and second radar area 41 simultaneously, but rather monitors only one of the two areas 31 , 41 for each detection cycle. This limits the computational load required of each radar sensor 2 .

[0035] Similar to the first detection mode, the second region of interest 4 as a whole is shaped to occupy all sides of the environment 100 that are free of the barrier 120. Furthermore, preferably, the second region of interest 4 does not cover the hazardous device 110.

[0036] Still similar to the first detection mode, in the second detection mode, in the presence of more than one radar sensor 2, the radar sensors 2 are configured to detect together the access of the object 200 to the second area of ​​interest 4. Therefore, the second area of ​​interest 4 may contain a union of multiple second radar areas 41 monitored by different radar sensors 2.

[0037] For at least one radar sensor 2, second radar region 41 is different from first radar region 31. However, it is not excluded that there may be radar sensors 2 for which first radar region 31 and second radar region 41 coincide.

[0038] It should be noted that in the illustrated embodiment, each active radar sensor 2 for monitoring the first region of interest 3 is also active for monitoring the second region of interest 4, and vice versa. However, in other examples, the radar sensors 2 active in the second detection mode may be generally inconsistent with the radar sensors 2 active in the first detection mode. In any case, at least one radar sensor 2 is active in both modes, thereby respectively monitoring the first radar area 31 and the second radar area 41, which are different from each other.

[0039] The second region of interest 4 is arranged such that an object 200 traveling along the access path 130 toward the hazardous device 110 encounters the second region of interest 4 after the first region of interest 3. In particular, a portion of the second region of interest 4 that is far from the environment 100 and / or the hazardous device 110 is closer to the environment 100 and / or the hazardous device 110 than a portion of the first region of interest 3 that is also far from the environment 100 and / or the hazardous device 110.

[0040] Preferably, the first region of interest 3 and the second region of interest 4 partially overlap, so that no uncovered area is left between the first region of interest 3 and the second region of interest 4. In an embodiment, the second region of interest 4 may be a subset of the first region of interest 3.

[0041] It should be noted that on the side of the environment 100 bounded by the barrier 120 it is generally unimportant whether the second region of interest 4 is inside or outside the first region of interest 3 , so in some embodiments parts of the second region of interest 4 may protrude from the first region of interest 3 .

[0042] Since the object 200 that continues to approach the hazardous device 110 after encountering the first area of ​​interest 3 encounters the second area of ​​interest 4, when the access of the object 200 is detected in the second area of ​​interest 4, the control system commands the hazardous device 110 to activate a second safety measure that is different from the first safety measure and is generally more severe than the first safety measure.

[0043] In a preferred embodiment, the second safety measure comprises stopping at least one movable part, preferably all movable parts, of the hazardous device 110. However, other safety measures are conceivable.

[0044] It should be noted that the security obtained by the above steps is equivalent to the security obtained with more computational burden by envisaging a single detection mode in which, at each cycle, the set of radar sensors 2 monitors access to both the first region of interest 3 and the second region of interest 4 .

[0045] If the object 200 does not invade the second region of interest 4 (eg Figure 4 As shown), the control system can evaluate whether the first safety measure is maintained. In particular, in the case where the object 200 is not detected in the second region of interest 4 within the first predetermined time, the control system controls the set of radar sensors 2 to return from the second detection mode to the first detection mode (i.e., interrupt the detection of the access to the object 200 in the second region of interest 4), and restart the detection of the access of the object 200 to the first region of interest 3.

[0046] By this mode change, the object 200 that has been previously detected in the first region of interest 3, which causes the transition from the first detection mode to the second detection mode, may remain in the first region of interest 3 or exit from the first region of interest 3. If the object 200 remains inside, the object 200 is immediately detected again in the first region of interest 3, and returns to the second detection mode. In this case, it is preferred that the first safety measure is not interrupted when exiting from the second mode, because such an interruption will have a very short duration.

[0047] Therefore, the control system commands the hazard device 110 to interrupt the first safety measure when no object 200 is detected in the second area of ​​interest 4 within a first predetermined time, which is necessary to return to the first mode, but preferably only after a further safety time has passed in which it is confirmed that there is no object 200 in the first area of ​​interest 3.

[0048] The dynamics described for the first region of interest 3 and the second region of interest 4 can be extended to a sequence of three or more regions of interest 3, 4 and thus to a corresponding number of detection modes. In each detection mode, the control system controls the set of radar sensors 2 to always start the detection of the access of the object 200 to the corresponding region of interest 3, 4 in the access path 130 one at a time.

[0049] The regions of interest 3, 4 are arranged in the access path 130 so that they are encountered by an object 200 travelling along the access path 130 towards the hazardous device 110 according to a predetermined sequence, starting with the first region of interest 3, then the second region of interest 4, until the last region of interest in the sequence.

[0050] When an access of an object 200 is detected in any region of interest 3, 4 other than the last region of interest, the control system controls the set of radar sensors 2 through different detection modes, thereby interrupting the detection of the access of the object 200 in the region of interest 3, 4 in question, and starting the detection of the access of the object 200 to the next region of interest in the sequence. In addition, when an access of an object 200 is detected in the respective region of interest 3, 4, different safety measures can be commanded.

[0051] Alternatively, when no object 200 is detected in any region of interest other than the first region of interest 3 within a predetermined time, the control system changes the detection mode again by controlling the set of radar sensors 2 to interrupt the detection of access of the object 200 to such region of interest, and starts the detection of access of the object 200 to the immediately preceding regions of interest 2, 3 in sequence.

[0052] In the following, for simplicity, reference will be made to the case of two regions of interest 3, 4, it being understood that the same may also be applied to longer sequences.

[0053] If an object 200 intrudes into the last area of ​​interest of the sequence (e.g., the second area of ​​interest 4), when the set of radar sensors 2 is in a relevant detection mode (e.g., the second detection mode), in an embodiment, in addition to activating the second safety measure, such a detection mode is simply maintained until no object 200 is detected for at least a first predetermined time.

[0054] In an alternative embodiment, upon detection of the access of an object 200 in the last region of interest 4 , the control system can command the interruption of the relative detection mode and the start of a different, further detection mode.

[0055] In a further detection mode, the set of radar sensors 2 is controlled to enable detection of objects 200 in a further region of interest 5, such as Figure 5 As shown, the further region of interest 5 is also identified by the union of one or more further radar regions 51. The further region of interest 5 covers at least a portion of the environment 100 that is not covered by the second region of interest 4. Preferably, the further region of interest 5 also completely covers the second region of interest 4 in addition to such a portion of the environment.

[0056] Thus, the second region of interest 4 extends at least in the access path 130 and only optionally also in a part of the environment 100 , while the further region of interest 5 extends at least in the environment 100 and only optionally in the access path 130 .

[0057] In the illustrated embodiment, the additional detection mode includes activating a radar sensor 2 that is inactive in the first detection mode and the second detection mode. In particular, such a radar sensor 2 is configured to monitor a radar region 51 in the vicinity of (e.g., above) the hazardous device 110. Thus, such a radar sensor 2 is not dedicated to detecting whether an object 200 has arrived in the immediate vicinity of the hazardous device 110 (which is considered to have occurred since the additional mode was activated after the object 200 was detected in the second region of interest). Instead, such a radar sensor 2 is dedicated to ensuring whether a physical interaction of the object 200 with the hazardous device 110 is ongoing or has terminated.

[0058] Therefore, radar sensor 2 that is active in the further detection mode may not generally correspond to radar sensor 2 that is active in the first detection mode and / or the second detection mode.

[0059] If the object 200 is not detected in the further region of interest 5 within at least a second predetermined time that is equal to or different from the first predetermined time, the detection of the presence of the object 200 in the further region of interest 5 can be interrupted, and the detection of access to the object 200 in the first region of interest 3 or the second region of interest 4, preferably in the second region of interest 4, can be started again.

[0060] It should be noted that in each detection mode, between the first detection mode, the second detection mode and the further detection mode, the set of radar sensors 2 can be configured to detect only the access of the object 200 to each region of interest 3, 4, 5, or to detect the access and persistence of the object 200 therein. This selection can be independent for different detection modes. For example, the first detection mode can be set to detect only the access, while the second detection mode and the further detection mode can be set to also detect the persistence.

[0061] In more detail, in the access-only detection mode, only mobile objects 200 are detected, while the set of radar sensors 2 is insensitive to fixed objects 200 , which are therefore excluded from detection in the regions of interest 3 , 4 , 5 in question.

[0062] This can be achieved in a known manner, for example, by removing only the background component representing the fixed object 200 from the radar signal and identifying the mobile object 200 after the background component has been subtracted. Thus, the access of the mobile object 200 at the region of interest 3, 4, 5 in question is detected, but after its persistence at the fixed position, the object 200 is no longer detected. On the other hand, this detection mode determines only a minimum number of false alarms.

[0063] Instead, in a detection mode that also detects the permanence of the object 200 , the safety measure will avoid being interrupted because the object 200 is no longer detectable when immobile.

[0064] In an example, according to techniques known to those skilled in the art, detecting the presence of the object 200 includes detecting the presence of a signal compatible with a vital sign in the involved region of interest 3, 4, 5. In another example, detecting the presence of the object 200 includes detecting fixed objects and moving objects in the involved region of interest 3, 4, 5, for example by avoiding removal of background components.

[0065] Depending on the number of radar sensors 2 , their arrangement and the shape of radar areas 31 , 41 , 51 monitored by individual radar sensors 2 , first area of ​​interest 3 , second area of ​​interest 4 and, if envisaged, further areas of interest 5 may assume generally different shapes.

[0066] In the example, first radar region 31 , second radar region 41 and / or further radar region 51 are each identified by a single circular sector 6 centered on the respective radar sensor 2 , as shown in FIG. Figure 1 Each circular sector 6 is defined by two sides 61 and a circular arc 62 opposite to the radar sensor 2, the two sides 61 are spaced apart from each other by a predetermined angle and converge to the radar sensor 2. The circular arc 62 is spaced apart from the radar sensor 2 by a predetermined radius and is connected to the side 61 at an outer vertex 63.

[0067] For simplicity, reference is made here to the shape of a circular sector 6, but for three-dimensional detection it should be understood that the radar region 31, 41, 51 is a volume that is identified by the circular sector 6 (in the sense that such a sector surrounds a plane of the volume) while two other surfaces (e.g. two planes 64 converging to the radar sensor 2) bound the volume from above and below.

[0068] If a single radar sensor 2 is envisaged, this can also be the overall shape of the first region of interest 3, the second region of interest 4 and / or the further region of interest 5. Alternatively, the regions of interest 3, 4, 5 are identified (on the plane) by the union of a plurality of circular sectors 6, each sector 6 being for a different radar sensor 2.

[0069] In another example, if Figure 2 As shown, radar regions 31 , 41 , 51 have been identified for each radar sensor 2 by a union of a plurality of circular sectors 6 that are all centered around the same radar sensor 2 . Figure 2 The shapes of radar regions 31, 41, 51 used in Figure 3 , Figure 4 and Figure 5 Adopted in.

[0070] Preferably, such circular sectors 6 are juxtaposed to one another along their sides 61. Thus, a first end sector 65 and a second end sector 66 are identified, as well as a plurality of intermediate sectors 67 between the end sectors 65,66.

[0071] In particular, it is preferred that, among the circular sectors 6 monitored by the same radar sensor 2 in the same detection mode, at least one end sector 65 , 66 (optionally both) has a smaller radius relative to the middle sector 67 .

[0072] exist Figure 2 In the embodiment of the invention, the sectors 6 of the first set 71 of circular sectors 6 (from the first end sector 65 to the extreme sector 68 selected from the intermediate sectors 67) all have the same maximum radius. Furthermore, the sectors 6 of the second set 72 of circular sectors 6 have increasing radius from the second end sector 66 having the smallest radius to the extreme sector 68. The outer vertices 63 of the sectors of the second set 72, in particular those facing away from the first end sector 65, are preferably aligned with each other along a line which is preferably substantially parallel to the side 61 of the first end sector 65.

[0073] Therefore, each radar region 31, 41 can present an irregular, asymmetric shape that approximates a quadrilateral. One of the sides is identified by the side 61 of the first end sector 65. The other side is identified by the arc 62 of the sector 6 of the first set 71 with the largest radius. Such a side, although not straight, is arched, but the larger the maximum radius, the smaller the arch and the more similar to a line segment. Another side is identified by the outer vertices 63 of the sector 6 of the second set 72, which are preferably at least three, but more preferably much more, such as at least ten. The last side is identified by the side 61 of the second end sector 66 with the smallest radius.

[0074] Depending on the mutual orientation of the first end sector 65 and the second end sector 66, the radar region 31, 41, 51 can present an overall polyhedral shape with an approximately rectangular plane, for example a substantially parallelepiped shape, in particular when the end sectors 65, 66 identify an angle of substantially 90°. Alternatively, as shown in the figure, although the shape of the individual radar regions 31, 41, 51 does not substantially have a rectangular plane, the radar sensors 2 in pairs can be arranged so that the union of their radar regions 31, 41, 51 is approximately rectangular in plane. To this end, the first end sectors 65, 66 of the respective radar sensors 2 in the pair are oriented toward the other radar sensor 2 in the pair.

[0075] In another embodiment not shown, the circular sectors 6 of the first set of sectors of the radar regions 31, 41, 51 have an increasing radius from a first end sector 65 to a first limiting sector with a maximum radius. Furthermore, the circular sectors 6 of the second set of sectors have an increasing radius from a second end sector 66 to a second limiting sector with a maximum radius. Preferably, the circular sectors of the third set of sectors, located between the first set and the second set, have a constant radius equal to the maximum radius.

[0076] Preferably, the outer vertices 63 of the sectors 6 of the first set, in particular those facing away from the second end sector 66, are aligned with each other on a first line, and the outer vertices 63 of the sectors 6 of the second set, in particular those facing away from the first end sector 65, are aligned with each other on a second line preferably parallel to the first line. Thus, there are two sides identified by the outer vertices 63 of the sectors 6 of the first set and the second set, respectively. The arrangement of the sectors of the first set and the second set may or may not be symmetrical. Furthermore, the sector with the smallest radius may be the first end sector or the second end sector, or both.

[0077] Again, by a suitable arrangement of a pair of radar sensors 2 facing each other, a union of the respective regions of interest 31 , 41 , 51 can be obtained in a substantially rectangular shape on a plane.

[0078] Also in these examples, the overall shape of the first region of interest 3 and / or the second region of interest 4 may correspond to the shape of a single radar region 31, 41, 51 (if only one radar sensor 2 is present), or may present a more complex shape (in the sense understood above, these more complex shapes are given by one or more radar regions 31, 41, 51 or a union of a pair of substantially quadrilateral radar regions 31, 41, 51), and optionally one or more radar regions 31, 41, 51 are given by a single circular sector. In these cases, at least one side of at least one radar region 31, 41, 51 and at least one side of the region of interest 3, 4, 5 are identified by a sequence of outer vertices 63 of circular sectors 6 (preferably at least three circular sectors 6) aligned with one another.

[0079] It should be noted that the use of relatively complex radar regions 31, 41, 51, which can be given by a plurality of circular sectors 6 for a single radar sensor 2, on the one hand increases the computational burden, but to an acceptable degree, since there is no simultaneous monitoring of the first region of interest 3, the second region of interest 4 (and if envisaged further regions of interest 5). On the other hand, this makes the overall shape obtainable for the first region of interest 3, the second region of interest 4 or the further region of interest 5 universal, without requiring an excessive increase in the number of radar sensors 2.

[0080] On the other hand, selecting a small number of possible shapes (eg the above-mentioned quadrilateral shapes) for the radar regions 31 , 41 , 51 , without including many possible customizations, simplifies the firmware of the radar sensor 2 .

[0081] Obviously, a person skilled in the art will be able to make many equivalent modifications to the above variations without thereby departing from the scope of protection defined by the appended claims.

Claims

1. A method for controlling access to an environment (100), comprising: - positioning a collection of one or more radar sensors (2) along an access path (130) to an environment (100) where a hazardous device (110) is present, - controlling the set of radar sensors (2) to initiate detection of an access by an object (200) to a first area of ​​interest (3) in the access path (130), - In case an access of an object is detected in said first region of interest (3): - commanding said hazardous device (110) to activate a first safety measure, - controlling said set of radar sensors (2) to interrupt the detection of access to an object (200) in said first area of ​​interest (3), and - controlling the set of radar sensors (2) to initiate detection of access by an object (200) to a second area of ​​interest (4) in the access path (130), the second area of ​​interest (4) being arranged such that an object (200) travelling along the access path (130) towards the hazardous device (110) encounters the second area of ​​interest (4) after the first area of ​​interest (3), - in the event of detection of access by an object (200) in said second area of ​​interest (4), commanding said hazardous device (110) to activate a second safety measure different from said first safety measure, and - in the event that no object (200) is detected in the second region of interest (4) within a first predetermined time: - controlling said set of radar sensors (2) to interrupt the detection of access to an object (200) in said second area of ​​interest (4), and - controlling said set of radar sensors (2) to initiate detection of a visit of an object (200) to said first area of ​​interest (3).

2. The method according to claim 1, wherein: The first region of interest (3) and / or the second region of interest (4) are identified by a union of a plurality of circular sectors (6).

3. The method according to claim 1 or 2, wherein: The first region of interest (3) and the second region of interest (4) respectively include a union of a plurality of first radar regions (31) monitored by different radar sensors (2) and a union of a plurality of second radar regions (41) monitored by different radar sensors (2).

4. The method according to claim 3, wherein: At least one first radar region (31) and / or at least one second radar region (41) has a shape with a plurality of sides, wherein at least one side is identified by a sequence of outer vertices (64) of circular sectors (6), preferably at least three circular sectors (6), aligned with one another.

5. The method according to any one of claims 1 to 4, wherein: - when controlled to detect access of an object (200) to the first region of interest (3), the set of radar sensors (2) is configured not to distinguish whether the respective object (200) is inside or outside the second region of interest (4), and - when controlled to detect access of an object (200) to the second region of interest (4), the set of radar sensors (2) is configured not to distinguish whether the respective object (200) is inside or outside the first region of interest (3).

6. The method according to any one of claims 1 to 5, comprising controlling the set of radar sensors (2) to start detecting, one at a time, access by an object (200) to three or more areas of interest (3, 4) in the access path (130), the three or more areas of interest (3, 4) comprising the first area of ​​interest (3) and the second area of ​​interest (4), the areas of interest (3, 4) being arranged such that an object (200) travelling along the access path (130) towards the hazardous device (110) encounters the areas of interest (3, 4) in a predetermined sequence, the steps comprising: - in the event that a visit of an object (200) is detected in each region of interest (3, 4) other than the last region of interest in the sequence, controlling the set of radar sensors (2) to interrupt the detection of a visit of the object (200) in this region of interest (3, 4) and to start the detection of a visit of the object (200) to a subsequent region of interest according to the sequence, and - in each region of interest other than the first region of interest (3) in the sequence, if no object (200) is detected within a predetermined time, controlling the set of radar sensors (2) to interrupt the detection of the visit of the object (200) in the region of interest and to start the detection of the visit of the object (200) to the previous region of interest according to the sequence.

7. The method according to any one of claims 1 to 5, comprising: - In case an access of an object (200) is detected in said second region of interest (4): - controlling said set of radar sensors (2) to interrupt the detection of access to an object (200) in said second area of ​​interest (4), - controlling the set of radar sensors (2) to initiate detection of an object (200) in a further region of interest (5) in the access path (130), the further region of interest (5) covering at least a portion of the environment (100) not covered by the second region of interest (4), - in the event that no object (200) is detected in the further region of interest (5) within a second predetermined time: - controlling the set of radar sensors (2) to interrupt the permanent detection of an object (200) in the further region of interest (5), and - controlling the set of radar sensors (2) to initiate detection of an access of an object (200) to the first region of interest (3) or the second region of interest (4).

8. The method according to any one of claims 1 to 7, wherein: The hazardous device (110) is a machine having a movable part, the first safety measure comprises slowing down the movement speed of the movable part, and the second safety measure comprises stopping the movable part.

9. The method according to any one of claims 1 to 8 comprises commanding the hazard device (110) to interrupt the first safety measure when no object (200) is detected in the second area of ​​interest (4) within a first predetermined time, preferably interrupting the first safety measure after a safety time has passed when no object (200) is detected in the first area of ​​interest (3).

10. A system for controlling access to an environment (100), comprising a collection of one or more radar sensors (2) positioned along an access path (130) to an environment (100) where a hazardous device (110) is present, and a control system, the control system being configured to: - controlling the set of radar sensors (2) to initiate detection of an access by an object (200) to a first area of ​​interest (3) in the access path (130), - in the event that access by an object (200) is detected in the first region of interest (3) by the set of radar sensors (2): - generating a control signal for activating a first safety measure by the hazardous device (110), - controlling said set of radar sensors (2) to interrupt the detection of access to an object (200) in said first area of ​​interest (3), and - controlling the set of radar sensors (2) to initiate detection of access by an object (200) to a second area of ​​interest (4) in the access path (130), the second area of ​​interest (4) being arranged such that an object (200) travelling along the access path (130) towards the hazardous device (110) encounters the second area of ​​interest (4) after the first area of ​​interest (3), - generating a command signal for activating, by the hazard device (110), a second safety measure different from the first safety measure, if access of an object (200) is detected by the set of radar sensors (2) in the second area of ​​interest (4), and - in the event that no object (200) is detected by the set of radar sensors (2) in the second region of interest (4) within a first predetermined time: - controlling said set of radar sensors (2) to interrupt the detection of access to an object (200) in said second area of ​​interest (4), and - controlling said set of radar sensors (2) to initiate detection of a visit of an object (200) to said first area of ​​interest (3).

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