Obstacle sensing device

Abstract

To provide an obstacle sensing device that can remove an obstacle that generates or may generate a portion where presence or absence of an obstacle cannot be sensed within a monitoring area.SOLUTION: An obstacle sensing device 10 includes a first laser distance measurement sensor 11 and a second laser distance measurement sensor 13 that scan a monitoring area MA with laser beams and receive reflected beams, which is configured to output an obstacle sensing signal when positions where the laser beams are reflected are in the monitoring area MA and to output an outside-area object sensing signal when the positions where the laser beams are reflected are in non-monitoring areas (a first non-monitoring area NMA1 and a second non-monitoring area NMA2).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an obstacle detection device that detects the presence or absence of an obstacle in a monitoring area. [Background technology]

[0002] One known example of this type of obstacle detection device is the obstacle detection device described in Patent Document 1. The obstacle detection device described in Patent Document 1 includes a detection device that is configured to detect whether or not there are obstacles such as people or vehicles within a set area within the railroad crossing, i.e., within a monitoring area, by receiving reflected light from a laser beam that scans within a predetermined angle range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-227608 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the obstacle detection device described in Patent Document 1 has a problem in that, if there is an object that blocks the laser light directed toward the set area (monitoring area), the object creates a part of the set area (monitoring area) within the railroad crossing where it is not possible to detect the presence or absence of an obstacle.For example, weeds may grow between the set area (monitoring area) and the detection device within the railroad crossing, and as such weeds grow, they may become an object that blocks the laser light directed toward the set area (monitoring area).

[0005] Therefore, an object of the present invention is to provide an obstacle detection device that can remove objects that cause or are likely to cause areas within a monitoring area where the presence or absence of an obstacle cannot be detected. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a novel obstacle detection device that includes a distance measuring sensor that scans a laser beam and receives reflected light, and is configured to output an obstacle detection signal when the reflected laser beam is within a monitored area, and to output an out-of-area object detection signal when the reflected laser beam is within a non-monitored area in front of the monitored area as viewed from the distance measuring sensor. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an obstacle detection device that can remove objects that cause or are likely to cause areas within a monitoring area where it is not possible to detect the presence or absence of obstacles. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a railroad crossing where an obstacle detection device according to an embodiment is installed; [Figure 2] FIG. 2 is a schematic plan view of the obstacle detection device. [Figure 3] FIG. 2 is a block diagram showing a schematic configuration of a control system of the obstacle detection device. [Figure 4] 4 is a flowchart illustrating an example of a process executed by the obstacle detection device. [Figure 5] 4 is a flowchart illustrating an example of a process executed by the obstacle detection device. [Figure 6] 4 is a flowchart illustrating an example of a process executed by the obstacle detection device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1 is a diagram showing a railroad crossing RC on which an obstacle detection device 10 according to an embodiment of the present invention is installed, FIG. 2 is a schematic plan view of the obstacle detection device 10, and FIG. 3 is a block diagram showing the control system configuration of the obstacle detection device 10 and the like.

[0011] First, a railroad crossing RC on which an obstacle detection device 10 according to the embodiment is installed will be described.

[0012] Referring to Fig. 1, the level crossing RC is equipped with level crossing warning devices 21, 21 and level crossing gates 22, 22 as level crossing safety devices. Here, the level crossing warning devices 21, 21 and the level crossing gates 22, 22 are installed on the near side and the far side of the tracks T1, T2, respectively, and road R is located on the near side and the far side of the tracks T1, T2, respectively, but the level crossing warning devices 21, 21, the level crossing gates 22, 22, and road R on the near side of the tracks T1, T2, and road R are omitted here. Also, although not shown in Fig. 1, a train detection unit 51 is installed on each of the tracks T1, T2 upstream of the level crossing RC in the direction of train travel for detecting that a train is approaching the level crossing RC (see Fig. 3). Furthermore, each of tracks T1 and T2 is equipped with an entry detection unit 52 for detecting when a train has entered a railroad crossing RC, and an exit detection unit 53 for detecting when a train has exited the railroad crossing RC (has passed through the railroad crossing RC) (see Figure 3).

[0013] The operation of the level crossing protection devices, i.e., the operation of the level crossing warning devices 21, 21 and the level crossing gates 22, 22, is controlled by a level crossing control device 23. When the level crossing control device 23 detects that a train is approaching the level crossing RC based on a detection signal from the train detection unit 51, it activates the level crossing protection devices. Specifically, the level crossing control device 23 activates the level crossing warning devices 21, 21 to warn those in the vicinity that a train is approaching the level crossing RC, and lowers the barrier bars 22a, 22a of the level crossing gates 22, 22 to prevent people, automobiles, etc. from entering the level crossing RC from the road R. Furthermore, when the level crossing control device 23 detects that a train has exited the level crossing RC (has passed through the level crossing RC) based on a detection signal from the exit detection unit 53, it stops the operation of the level crossing protection devices. Specifically, the railroad crossing control device 23 stops the operation of the railroad crossing warning devices 21, 21 and raises the barrier bars 22a, 22a of the railroad crossing barriers 22, 22 to allow people, vehicles, etc. to enter the railroad crossing road RC from the road R.

[0014] Next, the obstacle detection device 10 according to the embodiment will be described.

[0015] The obstacle detection device 10 is configured to detect the presence or absence of an obstacle in a monitoring area MA that is set mainly for the level crossing RC. In this embodiment, the monitoring area MA is set as a substantially rectangular area in a plan view that includes all or most of the level crossing RC, and the four corners C1 to C4 of the monitoring area MA are located outside the level crossing RC (see FIG. 2).

[0016] 1 to 3, the obstacle detection device 10 includes a first laser distance measuring sensor 11, a second laser distance measuring sensor 13, a processing unit 15, and a wireless communication unit 17.

[0017] The first laser ranging sensor 11 is a so-called ToF sensor, and is disposed outside the monitoring area MA and near a first corner C1 of the monitoring area MA. The first laser ranging sensor 11 is held at a first predetermined height by a support.

[0018] The second laser ranging sensor 13, like the first laser ranging sensor 11, is a so-called ToF sensor and is disposed outside the monitoring area MA and near a third corner C3 diagonally opposite the first corner C1. The second laser ranging sensor 13 is held at a second predetermined height, which is lower than the first predetermined height, by a support. In other words, the first laser ranging sensor 11 and the second laser ranging sensor 13 are positioned diagonally opposite each other across the monitoring area MA and are held at different heights.

[0019] The first laser ranging sensor 11 and the second laser ranging sensor 13 are configured to scan (two-dimensionally scan) a laser beam within a plane (i.e., a horizontal plane) parallel to the road surface of the level crossing RC within the monitoring area MA, and to receive reflected light of the scanned laser beam. More specifically, the first laser ranging sensor 11 and the second laser ranging sensor 13 are configured to (a) emit laser beams by changing the emission direction by a predetermined angle within an angular range that can cover the monitoring area MA along the plane (horizontal plane) parallel to the road surface of the level crossing RC, (b) receive reflected light of the emitted laser beam, and (c) calculate the distance to the reflection position of the laser beam based on the time difference between the emission timing of the laser beam and the reception timing of the reflected light of the laser beam.

[0020] The processing unit 15 stores information about the monitoring area MA. For example, the processing unit 15 stores the direction of and distance to each point on the boundary of the monitoring area MA as seen from the first laser ranging sensor 11, and the direction of and distance to each point on the boundary of the monitoring area MA as seen from the second laser ranging sensor 13.

[0021] The processing unit 15 receives input of information such as the direction of laser light emission and the distance to the reflection position of the laser light from each of the first laser ranging sensor 11 and the second laser ranging sensor 13. The processing unit 15 also receives input of detection signals from the train detection unit 51, the approach detection unit 52, and the exit detection unit 53.

[0022] The processing unit 15 is configured to detect whether or not there is an obstacle within the monitoring area MA, and if an obstacle is detected within the monitoring area MA, to notify the outside. This processing by the processing unit 15 is called "obstacle detection processing." Although not particularly limited, in this embodiment, the processing unit 15 is configured to perform obstacle detection processing when a detection signal from the train detection unit 51 is input, in other words, when a train approaches the level crossing RC and the level crossing protection device starts operating.

[0023] Specifically, the processing unit 15 determines whether the reflected position of the laser light emitted from the first laser ranging sensor 11 and / or the laser light emitted from the second laser ranging sensor 13 is within the monitoring area MA, and detects the presence of an obstacle in the monitoring area MA if the reflected position of the laser light is within the monitoring area MA. When the processing unit 15 detects the presence of an obstacle in the monitoring area MA, it outputs an obstacle detection signal indicating this to the wireless communication unit 17, and transmits it from the wireless communication unit 17 to a train approaching the railroad crossing RC, a management center, etc.

[0024] However, if an object exists that blocks the laser light directed toward the monitoring area MA, a portion of the monitoring area MA where it is not possible to detect whether or not an obstacle is present, i.e., a "blind spot" for obstacle detection, may occur. In this embodiment, two laser ranging sensors are provided on either side of the monitoring area MA. Therefore, even if the laser light directed toward the monitoring area MA from one laser ranging sensor is blocked, it is possible to detect whether or not an obstacle is present throughout the entire monitoring area MA based on information from the other laser ranging sensor. However, such a state is undesirable, and it is desirable to resolve it as quickly as possible.

[0025] Therefore, in this embodiment, the processing unit 15 is configured to detect whether there is an object that is blocking or is likely to block the laser light directed from the first laser ranging sensor 11 or the second laser ranging sensor 13 toward the monitoring area MA, and if the presence of such an object is detected, to notify the outside. This processing by the processing unit 15 is called "out-of-area object detection processing." Although not particularly limited, in this embodiment, the processing unit 15 is configured to perform out-of-area object detection processing when the level crossing protection device is not operating. The period when the level crossing protection device is not operating refers to any period between when a detection signal is input from the entrance detection unit 53 and when a detection signal is input from the train detection unit 51.

[0026] Specifically, processing unit 15 determines whether the reflection position of the laser light emitted from first laser ranging sensor 11 and / or second laser ranging sensor 13 is within the non-monitoring area NMA shown by hatching in Fig. 2, and if the reflection position of the laser light is within the non-monitoring area NMA, it detects the presence of an object that is or may be blocking the laser light directed toward the monitoring area MA from first laser ranging sensor 11 or second laser ranging sensor 13. When processing unit 15 detects the presence of an object that is blocking the laser light directed toward the monitoring area MA from first laser ranging sensor 11 or second laser ranging sensor 13, it outputs an out-of-area object detection signal indicating this to wireless communication unit 17, and transmits it from wireless communication unit 17 to a management center or the like.

[0027] Here, the non-monitored area NMA includes a first non-monitored area NMA1 that is within the scanning range of the laser light of the first laser ranging sensor 11 and is between the first laser ranging sensor 11 and the monitoring area MA, i.e., a first non-monitored area NMA1 on the near side of the monitoring area MA as seen from the first laser ranging sensor 11, and a second non-monitored area NMA2 that is within the scanning range of the laser light of the second laser ranging sensor 13 and is between the second laser ranging sensor 13 and the monitoring area MA, i.e., a second non-monitored area NMA2 on the near side of the monitoring area MA as seen from the second laser ranging sensor 13. The out-of-area object detection signal is a signal that mainly notifies a manager or the like that there is an object blocking the laser light directed from the first laser ranging sensor 11 or the second laser ranging sensor 13 to the monitoring area MA, and urges the manager or the like to remove the object.

[0028] 4 to 6 are flowcharts showing an example of processing performed by the obstacle detection device 10, more specifically, processing performed by the processing unit 15 of the obstacle detection device 10. FIG.

[0029] In step S1, the processing unit 15 determines whether or not a train is approaching the railroad crossing RC. This determination is made, for example, based on whether or not a detection signal from the train detection unit 51 has been input. If the train is approaching the railroad crossing RC, that is, if a detection signal from the train detection unit 51 has been input, the processing unit 15 proceeds to step S2 and performs obstacle detection processing (see FIG. 5). On the other hand, if the train is not approaching the railroad crossing RC, that is, if a detection signal from the train detection unit 51 has not been input, the processing unit 15 proceeds to step S3.

[0030] In step S3, the processing unit 15 determines whether or not to perform out-of-area object detection processing. Although not particularly limited, in this embodiment, the processing unit 15 determines to perform out-of-area object detection processing when the out-of-area object detection processing has not yet been performed or a predetermined time has elapsed since the previous out-of-area object detection processing. When the processing unit 15 determines to perform the out-of-area object detection processing, the processing proceeds to step S4 and performs the out-of-area object detection processing (see FIG. 6).

[0031] Fig. 5 is a flowchart showing an example of the obstacle detection process performed in step S2 of Fig. 4. In this obstacle detection process, as described above, it is detected whether or not there is an obstacle within the monitoring area MA.

[0032] In step S21, the processing unit 15 determines whether or not the train has entered the railroad crossing RC. This determination is made based on whether or not a detection signal has been input from the entry detection unit 52. If the train has not entered the railroad crossing RC, i.e., if a detection signal has not been input from the entry detection unit 52, the processing unit 15 proceeds to processing in step S22. On the other hand, if the train has entered the railroad crossing RC, i.e., if a detection signal has been input from the entry detection unit 52, the processing unit 15 ends this flow. Here, the reason for determining whether or not the train has entered the railroad crossing RC is to prevent the train from being detected as an obstacle.

[0033] In step S22, the processing unit 15 receives input of the emission direction of the laser light from the first laser distance measuring sensor 11 and the second laser distance measuring sensor 13 and the distance to the reflection position of the laser light.

[0034] In step S23, the processing unit 15 determines whether the reflected position of the laser light is within the monitoring area MA. If the reflected position of the laser light is within the monitoring area MA, the processing unit 15 proceeds to the processing of step S23. On the other hand, if the reflected position of the laser light is outside the monitoring area MA, the processing unit 15 returns to the processing of step S21.

[0035] In step S24, the processing unit 15 determines whether the reflected position of the laser beam is the same as the previous position. If the reflected position of the laser beam is the same as the previous position, the processing unit 15 proceeds to the processing of step S25. On the other hand, if the reflected position of the laser beam is different from the previous position, the processing unit 15 stores the reflected position of the laser beam and returns to the processing of step S21.

[0036] In step S25, processing unit 15 determines whether the laser beam is reflected at the same position N times in a row. N is an integer equal to or greater than 3 and is set in advance. If the laser beam is reflected at the same position N times in a row, processing unit 15 proceeds to processing in step S26. On the other hand, if the laser beam is not reflected at the same position N times in a row, processing unit 15 counts up the number of times the laser beam is reflected at the same position and returns to processing in step S21.

[0037] In step S26, the processing unit 15 assigns the reflection positions of the laser beam N times in succession to meshes for object tracking. Specifically, in this embodiment, the monitoring area MA is divided into N×M meshes, and among these meshes, a mesh corresponding to the reflection positions of the laser beam N times in succession is identified.

[0038] In step S27, the processing unit 15 determines whether or not the reflection positions of the laser beam N consecutive times are present within the same mesh for a predetermined period of time or more. If the reflection positions of the laser beam N consecutive times are present within the same mesh for a predetermined period of time or more, the processing unit 15 proceeds to the processing of step S28. On the other hand, if the reflection positions of the laser beam N consecutive times are not present within the same mesh for a predetermined period of time or more, the processing unit 15 returns to the processing of step S21.

[0039] In step S28, the processing unit 15 detects that there is an obstacle in the monitoring area MA (obstacle detection).

[0040] In step S29, the processing unit 15 outputs an obstacle detection signal to the wireless communication unit 17, which then transmits the signal to the train approaching the railroad crossing RC and the management center, etc. (obstacle notification).

[0041] Fig. 6 is a flowchart showing an example of the out-of-area object detection process performed in step S4 of Fig. 4. As described above, this out-of-area object detection process detects whether or not there is an object in the first non-monitoring area NMA1 and / or the second non-monitoring area NMA2, that is, whether or not there is an object that blocks or is likely to block the laser light directed from the first laser ranging sensor 11 or the second laser ranging sensor 13 toward the monitoring area MA.

[0042] In step S41, the processing unit 15 determines whether or not a train is approaching a railroad crossing RC. This determination is made based on whether or not a detection signal has been input from the train detection unit 51, similar to step S1 in FIG. 4. If the train is not approaching the railroad crossing RC, that is, if a detection signal has not been input from the train detection unit 51, the processing unit 15 proceeds to processing in step S42. On the other hand, if the train is approaching the railroad crossing RC, that is, if a detection signal has been input from the train detection unit 51, the processing unit 15 ends this flow.

[0043] In step S42, the processing unit 15 receives input of the direction of emission of the laser light from the first laser distance measuring sensor 11 and the second laser distance measuring sensor 13 and the distance to the position where the laser light is reflected.

[0044] In step S43, the processing unit 15 determines whether the reflected position of the laser light is within the non-monitoring area NMA, i.e., whether the reflected position of the laser light is within the first non-monitoring area NMA1 or the second non-monitoring area NMA2. If the reflected position of the laser light is within the non-monitoring area NMA, the processing unit 15 proceeds to the processing of step S44. On the other hand, if the reflected position of the laser light is outside the non-monitoring area NMA, the processing unit 15 ends this flow.

[0045] In step S44, the processing unit 15 determines whether the reflected position of the laser beam is the same as the previous position. If the reflected position of the laser beam is the same as the previous position, the processing unit 15 proceeds to the processing of step S45. On the other hand, if the reflected position of the laser beam is different from the previous position, the processing unit 15 stores the reflected position of the laser beam and returns to the processing of step S41.

[0046] In step S45, the processing unit 15 determines whether the state in which the reflected position of the laser beam remains the same continues for a certain period of time or more. If the state in which the reflected position of the laser beam remains the same continues for a certain period of time or more, the processing unit 15 proceeds to the processing of step S46. On the other hand, if the state in which the reflected position of the laser beam remains the same does not continue for a certain period of time or more, the processing unit 15 returns to the processing of step S41.

[0047] In step S46, the processing unit 15 detects that there is an object within the non-monitoring area NMA, i.e., that there is an object that is blocking or is likely to block the laser light directed from the first laser ranging sensor 11 or the second laser ranging sensor 13 toward the monitoring area MA (detection of an object outside the area).

[0048] In step S47, the processing unit 15 outputs an out-of-area object detection signal to the wireless communication unit 17, and transmits it to a management center or the like from the wireless communication unit 17 (out-of-area object notification).

[0049] According to the obstacle detection device 10 according to the embodiment, for example, the following effects can be obtained.

[0050] The processing unit 15 of the obstacle detection device 10 is configured to input the emission direction of the laser light and the distance to the reflected position of the laser light from the first laser ranging sensor 11 and the second laser ranging sensor 13, output an obstacle detection signal if the reflected position of the laser light is within the monitoring area MA, and output an outside-area object detection signal if the reflected position of the laser light is within the non-monitoring area NMA (NMA1, NMA2). Therefore, not only can the processing unit 15 detect the presence of an obstacle within the monitoring area MA and notify the outside, but it can also detect and notify the outside of an object that creates or is likely to create a blind spot for obstacle detection within the monitoring area MA, thereby urging the removal of such an object. Therefore, it is possible to quickly remove an object that creates or is likely to create a blind spot for obstacle detection within the monitoring area MA.

[0051] Furthermore, the processing unit 15 of the obstacle detection device 10 is configured to perform out-of-area object detection processing when the railroad crossing protection device is not operating, and to output an out-of-area object detection signal when the reflected position of the laser light within the non-monitored area NMA remains the same for a certain period of time or more, i.e., when the reflected position of the laser light within the non-monitored area NMA does not change for a certain period of time or more. Therefore, the out-of-area object detection processing can be performed without affecting the obstacle detection processing or train operation, and the output of unnecessary out-of-area object detection signals can be suppressed.

[0052] The obstacle detection device 10 is configured to detect the presence or absence of an obstacle in a monitoring area MA set mainly for a railroad crossing RC. However, this is not limited thereto. The obstacle detection device 10 may be configured to detect the presence or absence of an obstacle in any monitoring area.

[0053] In the above-described embodiment, the processing unit 15 of the obstacle detection device 10 determines whether the train has entered the railroad crossing RC to prevent the train from being detected as an obstacle, and terminates the obstacle detection process when the train has entered the railroad crossing RC. However, this is not limited to this. For example, the processing unit 15 of the obstacle detection device 10 may be configured to perform the obstacle detection process until the train exits the railroad crossing RC, and to stop outputting the obstacle detection signal from the time the train enters the railroad crossing RC until the time the train exits the railroad crossing RC.

[0054] Furthermore, in the above-described embodiment, the processing unit 15 of the obstacle detection device 10 performs out-of-area object detection processing when the railroad crossing protection device is not operating, and transmits an out-of-area object detection signal to a management center or the like via the wireless communication unit 17. However, this is not limited to this. The processing unit 15 of the obstacle detection device 10 may perform the obstacle detection processing and the out-of-area object detection processing simultaneously when there is no risk of affecting the obstacle detection processing or train operation.

[0055] The above describes the embodiments of the present invention and their modifications. However, the present invention is not limited to the above-described embodiments and modifications, and it goes without saying that further modifications and changes are possible based on the technical concept of the present invention. [Explanation of symbols]

[0056] 10...obstacle detection device, 11...first laser distance measuring sensor, 13...second laser distance measuring sensor, 15...processing unit, 17...wireless communication unit, 21...railroad crossing alarm, 22...railroad crossing barrier, 23...railroad crossing control device, 51...train detection unit, 52...entrance detection unit, 53...exit detection unit, R...road, RC...railroad crossing, T1, T2...railroad tracks

Claims

1. An obstacle detection device that includes a distance measuring sensor that scans laser light and receives reflected light, and outputs an obstacle detection signal when the reflected position of the laser light is within a monitored area, and outputs an out-of-area object detection signal when the reflected position of the laser light is within a non-monitored area in front of the monitored area as viewed from the distance measuring sensor.

2. 2. The obstacle detection device according to claim 1, wherein the out-of-area object detection signal is output when the reflection position of the laser light within the non-monitored area does not change.

3. 3. The obstacle detection device according to claim 1, wherein the non-monitored area is an area that is within a scanning range of the laser light of the distance measuring sensor and is between the distance measuring sensor and the monitored area.

4. The monitoring area is set for a railroad crossing, determining whether the reflected position of the laser light is within the non-monitoring area when a railroad crossing protection device installed at the railroad crossing is not operating; 3. An obstacle detection device according to claim 1 or 2.

5. 3. The obstacle detection device according to claim 1, wherein a pair of distance measuring sensors are arranged on either side of the monitoring area.

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