JP6396647B2 - Obstacle detection device and obstacle detection method - Google Patents

Description

  The present invention relates to an obstacle detection device and an obstacle detection method for detecting an obstacle on a train.

  As a technique for detecting an obstacle in a train, a vehicle radar system described in Japanese Patent Laid-Open No. 2001-116840 (Patent Document 1) has been proposed. In the vehicle radar system, a radar mounted on a train emits radio waves and measures reflected waves to detect obstacles existing on and around the track.

JP 2001-116840 A

  Radar detection objects, such as buildings around the orbit, are not always the same, and may change due to rebuilding, new construction, relocation, and the like. For this reason, it is difficult to distinguish whether the object detected by the radar is a permanent building or an obstacle such as a vehicle that has entered the track, and the obstacle recognition rate is good. It wasn't.

  Accordingly, an object of the present invention is to provide an obstacle detection device and an obstacle detection method that improve the recognition rate of obstacles.

The obstacle detection device is mounted on the train and outputs a peak signal proportional to the size of the object in the search range, position detection means for detecting the position of the train, and output from the radar while the train is running. Determining means for determining whether there is an obstacle in the radar search range based on a difference between the peak signal and the reference signal when there is no obstacle at the train position detected by the position detecting means; Have.

In the obstacle detection method, the control device is mounted on the train while the train is running, reads the radar output signal that outputs a peak signal proportional to the size of the object in the search range, and the peak signal output from the radar And whether or not there is an obstacle in the search range of the radar, based on the difference from the reference signal when there is no obstacle stored in the storage means at the train position.

  ADVANTAGE OF THE INVENTION According to this invention, the recognition rate of the obstruction of a train can be improved.

An example of an obstacle detection apparatus is shown, (A) is the block diagram which looked at the train from the side, (B) is the block diagram which looked at the train from upper direction. An example of the output characteristic of a radar is shown, (A) is an explanatory view of a building existing in the search range of the radar, and (B) is an explanatory view of an output signal of the radar. An example of the reference signal accumulated in the database is shown, (A) is an explanatory diagram of the situation when the train arrives at a predetermined point, and (B) is an explanatory diagram of the reference signal at points A to C. An example of an obstacle detection method is shown, (A) is an explanatory diagram of the situation when a train arrives at point B, and (B) is an explanatory diagram of a radar output signal, a reference signal, and their differences. It is a flowchart which shows an example of an obstacle detection process. The problem of the obstacle detection by a radar is shown, (A) is explanatory drawing of the positional relationship of a train and two obstacles, (B) is explanatory drawing of the output signal of a radar. It is explanatory drawing of the method of solving the problem of the obstacle detection by a radar.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of an obstacle detection device.

  A radar 110 that detects obstacles on the track 200 and in the search range 300 around it by emitting a radio wave such as a millimeter wave toward the front of the train 100 and measuring the reflected wave. Is installed. The output signal of the radar 110 is input to the control device 120 incorporating a computer. In addition, the control device 120 receives an output signal from the position detection unit 130 that detects the position of the train 100. As the position detection means 130, for example, an tacho generator, a ground element installed along the orbit 200, a GPS (Global Positioning System), or the like can be used. The radio waves emitted by the radar 110 are not limited to millimeter waves, and may be radio waves having other wavelengths.

  As shown in FIG. 2A, when the building 400 exists in the search range 300 in front of the train 100 as shown in FIG. 2A, as shown in FIG. An output signal corresponding to the size is output. Specifically, when there are four buildings 400 in the search range, the radar 110 outputs an output signal in which a peak signal proportional to the size of the building 400 appears for each distance from the radar 110 to each building 400. To do. In the output signal shown in FIG. 2B, four peak signals corresponding to the four buildings 400 are seen.

  Further, in order to determine whether or not there is an obstacle in the search range 300 in the train 100 by comparison with the output signal of the radar 110, a database 140 that stores a reference signal when there is no obstacle is provided. It is installed. The database 140 is constructed using, for example, a hard disk drive, a flash ROM (Read Only Memory), and the like, and is connected so as to be accessible from the control device 120. The reference signal stored in the database 140 is an output signal that is assumed to be output by the radar 110 at a predetermined point when there is no obstacle ahead of the train 100. The database 140 is an example of a storage unit.

  FIG. 3 assumes that when two buildings 400 (which are not obstacles) are present in front of the train 100, the radar 110 will output at points A, B and C, which are examples of predetermined points. The reference signal is shown. When the train 100 arrives at the point A, the distance from the train 100 to the building 400 is far away. Therefore, in the reference signal at the point A, two peak signals indicating the building 400 appear in a region with a large distance. When the train 100 travels to the point B, the distance from the train 100 to the building 400 becomes shorter than the point A. Therefore, in the reference signal at the point B, two peak signals indicating the building 400 in the medium distance region are displayed. Appears. Then, when the train 100 travels to the point C, the distance from the train 100 to the building 400 is further shortened compared to the point B. Therefore, in the reference signal at the point C, two peak signals indicating the building 400 in a region where the distance is small. Appears. As described above, the database 140 stores a plurality of reference signals in advance for each predetermined point along the track 200 of the train 100.

Here, an example of the obstacle detection method by the obstacle detection apparatus will be described.
When the train 100 arrives at a point B, as shown in FIG. At this time, the radar 110 mounted on the train 100 outputs an output signal in which the peak signal indicating the vehicle 500 is superimposed in addition to the peak signal indicating the two buildings 400. On the other hand, in the database 140, as a reference signal at the point B, an output signal when the vehicle 500 does not exist at a railroad crossing or the like is accumulated. If the difference between the output signal of the radar 110 and the reference signal at the point B is obtained, this represents the vehicle 500. Therefore, based on the difference between the output signal of the radar 110 and the reference signal when the train 100 is traveling, it can be determined whether there is an obstacle in the search range of the radar 110.

  When determining whether or not there is an obstacle in the search range of the radar 110, if the reference signal stored in the database 140 is sequentially updated, for example, the detection target can be detected by rebuilding, newly building, moving, or the like of the building 400. Even if it changes, it becomes possible to distinguish a building and an obstacle, and the recognition rate of an obstacle can further be improved. In this case, for example, the reference signal of the database 140 may be updated as appropriate using the output signal of the radar 110 measured during the maintenance work at midnight.

  FIG. 5 shows an example of an obstacle detection process that is repeatedly executed by the control device 120 every predetermined time when the train 100 is traveling. The determination unit is realized by the control device 120 executing the obstacle detection process.

  In step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), the control device 120 reads the position of the train 100 from the position detection means 130.

  In step 2, the control device 120 determines whether or not the train 100 has come to a predetermined point, in other words, whether or not the train 100 has come to a point where an obstacle ahead is detected. Here, the predetermined point is represented by, for example, longitude and latitude, and is registered in the database 140 in advance. The control device 120 advances the process to step 3 if it is determined that the train 100 has arrived at a predetermined point (Yes), and ends the process if it is determined that the train 100 has not arrived at the predetermined point (No). .

In step 3, the control device 120 reads the output signal of the radar 110.
In step 4, the control device 120 reads a reference signal at a predetermined point from the database 140.

  In step 5, the control device 120 calculates the difference between the output signal of the radar 110 and the reference signal at a predetermined point.

  In step 6, the control device 120 determines whether or not the difference calculated in step 5 is greater than or equal to a predetermined value. Here, the predetermined value is a threshold for suppressing noise or the like superimposed on the output signal of the radar 110 and erroneously detecting an obstacle, and is appropriately set according to the output signal characteristics of the radar 110, for example. can do. Then, if it is determined that the difference is greater than or equal to the predetermined value, the control device 120 advances the process to Step 7 (Yes), and if the difference is determined to be less than the predetermined value, the control device 120 ends the process (No). If there is a difference between a plurality of peak signals between the output signal and the reference signal, it is determined whether or not the difference is greater than or equal to a predetermined value for each peak signal, and at least one difference is greater than or equal to a predetermined value. If so, the process may proceed to step 7.

  In step 7, the control device 120 activates an alarm device such as a lamp or a buzzer attached to the driver's seat of the train 100 in order to notify that there is an obstacle ahead of the train 100.

  According to the obstacle detection process, when the train 100 arrives at a predetermined point, the control device 120 calculates the difference between the output signal of the radar 110 and the reference signal at the predetermined point, and whether or not this is equal to or greater than a predetermined value. Determine. If the control device 120 determines that the difference between the output signal and the reference signal is equal to or greater than a predetermined value, the control device 120 activates an alarm device such as a lamp or a buzzer to notify that there is an obstacle ahead of the train 100. To do. Therefore, the obstacle detection method can be executed by the obstacle detection device.

  In the search range 300 of the radar 110, as shown in FIG. 6A, when the vehicle 500 and the human 600 exist at substantially the same distance, as shown in FIG. 6B, the peak signal indicating the human 600 is obtained. Is hidden by a peak signal indicating the vehicle 500. This is because the vehicle 500 is larger than the human 600 and the peak signal indicating the human 600 becomes invisible.

  Therefore, as shown in FIG. 7, it may be determined whether there is an obstacle for each of the divided regions 702 to 732 obtained by dividing the region 700 where the obstacle is detected by the radar 110 into a plurality of regions. In this case, the search for each of the divided regions 702 to 732 by the radar 110 can be performed, for example, by scanning at least one of the angle and direction in which the radar 110 emits radio waves.

  In this way, even when different obstacles exist at substantially the same distance from the radar 110, the possibility of detecting this increases, and the safety related to the operation of the train 100 can be improved.

  The number of divisions for dividing the area 700 is not limited to the 16 divisions shown in FIG. Each divided area obtained by dividing the area 700 may be different in size, for example, by making an important partition finer (smaller) than others. In this case, the number of divisions of the area 700, the size of the division area, and the like can be determined in consideration of the characteristics of the radar 110, the processing capability of the control device 120, and the like.

  Note that the radar 110 is not limited to the front part of the train 100 but can be mounted on at least one of the front part and the rear part of the train 100.

100 train 110 radar 120 control device 130 position detection means 140 database 200 track 300 search range 400 building 500 vehicle 600 human 700 region 702 to 732 divided region

Claims (6)

A radar mounted on a train that outputs a peak signal proportional to the size of an object within the search range;
Position detecting means for detecting the position of the train;
While the train is running, based on the difference between the peak signal output from the radar and the reference signal when there is no obstacle at the train position detected by the position detection means, the search range of the radar is set. A determination means for determining whether an obstacle exists;
An obstacle detection device comprising: The determination means determines that there is an obstacle in the search range of the radar when the difference between the peak signal output from the radar and the reference signal is a predetermined value or more.
The obstacle detection apparatus according to claim 1. The reference signal is updated sequentially.
The obstacle detection device according to claim 1 or 2, characterized by the above. The radar can change the emission angle and emission direction of radio waves,
The obstacle detection device according to any one of claims 1 to 3, wherein The determination means determines whether or not the obstacle exists for each divided area obtained by dividing an obstacle detection area into a plurality of areas.
The obstacle detection apparatus according to any one of claims 1 to 4, wherein the obstacle detection apparatus is characterized in that: The control unit
While the train is running, read the radar output signal that is mounted on the train and outputs a peak signal proportional to the size of the object within the search range,
Whether or not there is an obstacle in the radar search range based on the difference between the peak signal output from the radar and the reference signal when no obstacle is stored in the storage means at the train position. Determine
An obstacle detection method characterized by that.