JP2013061690A - Obstacle detection system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an obstacle detection system for a vehicle which can prevent erroneous detection of irregularities of a road surface as an obstacle.SOLUTION: An obstacle detection system for a vehicle includes: a first side surface part sensor installed on a front side surface part of a vehicle; a second side surface part sensor which is installed on a rear side surface part of the vehicle and on the same side surface as the first side surface part sensor out of left and right side surfaces of the vehicle; and obstacle detection means. A threshold for detecting an obstacle by the second side surface part sensor is set on the basis of a reflected wave from the first side surface part sensor, so that a user can be precisely informed of an obstacle existing in a detection range on the rear side of his or her vehicle.

Description

  The present invention relates to an obstacle detection system for a vehicle, and more particularly to an obstacle detection technique for detecting a moving obstacle moving on a road.

  As a conventional technique, for example, an obstacle detection technique disclosed in Patent Document 1 is known. In Patent Document 1, a radio wave is irradiated by a millimeter wave radar in a direction that becomes a driver's blind spot such as a side of a vehicle, and a reflected wave of the radio wave is received. Then, it is determined whether or not an obstacle exists by comparing the reflectance with a threshold value.

  Furthermore, in patent document 1, the traveling lane of the own vehicle is specified from the measurement result of the navigation system, and it is determined from the identified traveling lane of the own vehicle that there is a possibility that other vehicles exist on the left and right of the own vehicle. And when detecting an obstacle with respect to the side judged that there is no possibility that another vehicle exists, in order not to detect roadside objects, such as a guardrail, a high threshold value is used.

JP 2008-40819 A

  The thing of patent document 1 has changed the threshold value for determining with an obstruction by a driving lane, but if a driving lane is the same, a threshold value is a fixed value. Naturally, this threshold value is set to a value higher than the intensity of the reflected wave generated by being reflected by the road surface.

  However, even in the same traveling lane, the degree of unevenness on the road surface may vary depending on the location. Depending on the degree of unevenness on the road surface, the intensity of the reflected wave from the unevenness may increase. Therefore, in the technique of Patent Document 1, there is a possibility that the unevenness on the road surface is erroneously detected as an obstacle.

  Then, an object of this invention is to provide the obstruction detection system for vehicles which can suppress misdetecting the unevenness | corrugation of a road surface as an obstruction.

  In order to achieve the above object, the invention according to claim 1 is installed on a front side surface portion of a vehicle, transmits a signal wave toward a detection range on the front side of the vehicle, and the signal wave is an obstacle. A first side surface sensor that receives a reflected wave reflected by the vehicle, and a rear side surface portion of the vehicle, the left side surface of the vehicle being installed on the same side surface as the first side surface sensor, and the rear side of the vehicle A second side surface sensor that transmits a signal wave toward the side detection range and receives the reflected wave reflected by the obstacle, and the intensity of the reflected wave received by the first side surface sensor And an obstacle in the front detection range based on the first sensor threshold, and based on the intensity of the reflected wave received by the second side surface sensor and the second sensor threshold, Obstacles that detect obstacles in the detection range An obstacle detection system for a vehicle, comprising: a detection unit; and a notification unit that notifies that an obstacle has been detected when the obstacle is detected by the obstacle detection unit, the obstacle detection unit Is characterized in that the second sensor threshold is set based on the reflected wave of the first side surface sensor.

  As described above, the reflected wave of the first side surface sensor reflects the road surface condition at that time, and the obstacle detection means sets the second sensor threshold based on the reflected wave of the first side surface sensor. doing. Therefore, this second sensor threshold value can be set to a threshold value according to the road surface situation at that time.

  In particular, the first side sensor and the second side sensor are installed on the same left and right sides of the vehicle, and if the road surface condition around the vehicle is the same in the left-right direction with respect to the vehicle, the front and rear parts of the vehicle In many cases, there is not much difference. Therefore, by setting the second sensor threshold based on the reflected wave of the first side sensor installed on the same side as the second side sensor, the second sensor threshold is set to a threshold that accurately reflects the road surface condition at that time. Can do.

  Further, the road surface range that is the detection range of the first side surface sensor becomes the detection range of the second side surface sensor after the vehicle travels forward. The road surface that is detected by the second side surface sensor can be set as the detection range earlier than the two side surface sensors. Therefore, by setting a threshold value for comparison with the reflected wave of the second side surface sensor based on the reflected wave at the first side surface sensor, the road surface irregularities in the rear side detection range can be obstructed early. Can be prevented from being erroneously detected. As a result, it is possible to accurately notify the user of obstacles existing in the detection range on the rear side of the vehicle.

  The invention according to claim 2 is characterized in that a maximum value of the intensity of the reflected wave received by the first side surface sensor for a certain period is sequentially set as the second sensor threshold value.

  Thereby, even when a reflected wave higher than the second sensor threshold set in advance to prevent notification related to the road surface condition is detected from the road surface, the change in the road surface can be excluded from the obstacle and notified. it can.

  Further, the second sensor threshold value may be changed as described in claim 3. In the invention according to claim 3, the obstacle detection means detects the obstacle by setting the second sensor threshold to either a high threshold or a low threshold lower than the high threshold. The second sensor threshold value is set to a high threshold value based on the fact that the intensity of the reflected wave received by the first side surface sensor exceeds the first sensor threshold value.

  Further, when the second sensor threshold value is set to a high threshold value as in claim 3, it is preferable that the second sensor threshold value is changed to a low threshold value as in claim 4. In the invention according to claim 4, when the second sensor threshold is a high threshold, the obstacle detection means is configured such that the intensity of the reflected wave received by the first side surface sensor is equal to or longer than the first sensor threshold. If not exceeded, the second sensor threshold value is changed to a low threshold value.

1 is a schematic diagram illustrating an overall configuration of a vehicle obstacle detection system 1 to which the present invention is applied. It is a model figure showing the installation location of sonar 2a, 2b of FIG. It is a flowchart explaining the obstacle detection process of ECU4 corresponding to 1st Embodiment. It is a flowchart explaining the obstacle detection process of ECU4 corresponding to 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram showing an overall configuration of an obstacle detection system 1 in the present embodiment. The obstacle detection system 1 includes a plurality of sonars 2 a, 2 b, 2 c, 2 d, a notification device 3 that informs the user of the detection of the obstacle, and an ECU 4 that controls each sonar 2 and the notification device 3.

  FIG. 2 is a model diagram showing the installation locations of the sonars 2a and 2b. The front side sonar 2a is installed on the side surface 6 of the front bumper, the rear side sonar 2b is installed on the side surface 7 of the rear bumper, and the front side sonar 2a and the rear side sonar 2b are the same on the left and right sides of the vehicle body 5 (in FIG. 5 on the left). Further, as shown in FIG. 2, the detection ranges 8 a and 8 b of the respective sonar are the left diagonal front and the left diagonal rear of the vehicle, and the detection range of the left diagonal rear includes a range that is a blind spot of the driver. It is out. In the following, it is assumed that the rear sonar detection range is the rear blind spot.

  Further, the front side sonar 2c and the rear side sonar 2d are installed on the side surface opposite to the above-described sonars 2a and 2b. Each of these four sonars 2 outputs an ultrasonic wave toward each detection range, and receives a reflected wave in which the ultrasonic wave is reflected by an obstacle, a road surface, or the like. Sensors 2a and 2b are paired, and sensors 2c and 2d are paired. The front side sonars 2a and 2c correspond to the first side surface sensor in the claims, and the rear side sensors 2b and 2d correspond to the second side surface sensor in the claims.

  As described above, the front side sonar 2 a and the rear side sonar 2 b are installed on the same side in the left and right sides of the vehicle body 5, and the detection range is also on the same side in the left and right direction of the vehicle body 5. Here, as for the road surface condition around the vehicle, if the left-right direction with respect to the vehicle is the same, there is often no significant difference between the front part and the rear part of the vehicle. The obstacle detection system 1 of the present embodiment utilizes this fact, and reflects the reflected wave detected by the front side sonar 2a as a rear threshold value (corresponding to the second sensor threshold value in the claims) as a notification threshold value of the rear side sonar 2b. It is used for. As a result, the rear threshold value can be set to a threshold value that accurately reflects the road surface condition at that time.

  Next, the obstacle detection process executed by the ECU 4 including the above-described rear threshold setting process will be described. FIG. 3 is a flowchart for explaining the obstacle detection process of the ECU 4. Note that the processing shown in FIG. 3 is repeatedly executed at a predetermined cycle.

  First, in step S20, a reception signal is acquired from the front side sonars 2a and 2c. In this process, first, ultrasonic waves are output from the front side sonars 2a and 2c. The ultrasonic waves output from the front side sonars 2a and 2c are reflected by obstacles and road surfaces in the detection ranges of the sonars 2a and 2c to generate reflected waves, and the reflected waves are received by the sonars 2a and 2c. ECU4 acquires the signal (henceforth a received signal) which shows this reflected wave which sonar 2a, 2c received.

  In step S21, the rear threshold value is determined with reference to the reception signals of the front side sonars 2a and 2c acquired in step S20.

  Specifically, the maximum intensity is determined among the received signals for a certain period acquired from the front side sonar 2a. Then, the determined maximum intensity is set as a rear threshold value. Accordingly, if the intensity of the reflected wave of the rear side sonar 2b is equal to or less than the maximum intensity of the received signal detected by the front side sonar 2a, it is not detected as an obstacle. Therefore, even if road surface unevenness equivalent to the road surface unevenness of the detection range of the front side sonar 2a is present in the detection range of the rear side sonar 2b, erroneous detection due to the presence of the unevenness is suppressed.

  The same process is performed for the sonars 2c and 2d installed on the side of the vehicle body opposite to the front side sonars 2a and 2b, and the rear threshold value is set.

  And after setting a rear threshold value, a reception signal is acquired also from rear side sonar 2b, 2d in step S22. This process is the same as step S20. Note that the order of the processing of step S22 and step S21 may be switched, and step S22 may be executed first.

  In the subsequent step S23, the threshold value set for each sonar 2a, 2b, 2c, 2d is compared with the intensity of the received signal acquired from each sonar 2a, 2b, 2c, 2d. As the threshold values of the rear side sonars 2b and 2d, the values set in step S21 are used. On the other hand, for the front threshold value (first sensor threshold value) which is the threshold value of the front side sonars 2a and 2c, a constant value set in advance is used.

  As a result of the comparison between the threshold and the intensity of the received signal, it can be determined that an obstacle exists when the intensity of at least one received signal exceeds the threshold. In this case, an affirmative decision is made in step S23 and the process proceeds to step S24. On the other hand, if the intensity of all received signals is smaller than the threshold value, the process shown in FIG. 3 is terminated without executing step S24.

  In step S24, the notification device 3 connected to the ECU 1 notifies the driver that there is an obstacle.

  Thus, according to the flowchart of FIG. 3, by setting the intensity of the reception signal of the front side sonars 2a and 2c as the rear threshold value, the rear side sonars 2b and 2d are moved forward to the detection ranges of those sonars 2b and 2d. Even if there is a road surface unevenness similar to the road surface unevenness in the detection range 8a, it is possible to suppress erroneous detection that an obstacle exists due to the presence of the unevenness.

  Further, the processing of FIG. 3 is repeatedly performed, that is, the rear threshold is updated based on the reception signals of the front side sonars 2a and 2c. Therefore, the unevenness of the road surface at that time can be reflected in the notification threshold.

  Further, since the front side sonars 2a and 2c used for setting the rear threshold are sonars on the same side as the rear side sonars 2b and 2d, the notification threshold value accurately reflecting the road surface irregularities of the rear side sonars 2b and 2d. Can be set.

  Further, when the vehicle is traveling forward, the road surface range that is the detection range of the front side sonars 2a and 2c becomes the detection range of the rear side sonars 2b and 2d after that. By setting the intensity of the received signal as the rear threshold, it is possible to prevent early detection of road surface unevenness in the detection range 8b on the rear side as an obstacle.

  For these reasons, by setting the intensity of the reception signals of the front side sonars 2a and 2c as the rear threshold value, erroneous detection is suppressed, and obstacles in the rear detection range 8b can be notified more accurately. .

(Second Embodiment)
Next, a second embodiment will be described. In the second embodiment, the obstacle detection system 1 of FIG. 1 does not set the maximum intensity of the reflected wave for a certain period of time acquired from the front side sonar 2a to the rear threshold as in the first embodiment, but instead of setting the rear threshold value. The intensity of the reflected wave acquired from the above and the front threshold value are compared, and the rear threshold value is determined as either the high setting threshold value or the low setting threshold value.

  A processing flow in the second embodiment will be described with reference to FIG. The process of FIG. 4 is periodically repeated.

  After receiving reception signals of reflected waves from the front side sonars 2a and 2c and the rear side sonars 2b and 2c (S30), it is confirmed whether the rear threshold value is a “high setting” threshold value or a “low setting” threshold value. (S31). If it is “high setting”, the process proceeds to S34. When it is not “high setting”, that is, when it is “low setting”, it is determined whether or not the intensity of the reflected waves of the front side sonars 2a and 2c received in S30 is larger than the front threshold ( S32). As a result of the determination, if it is larger than the threshold, the rear threshold setting is changed to “high setting”, and if it is smaller than the threshold, the process proceeds to S34. In this way, when the received signal acquired from the front side sonars 2a and 2c is larger than the front threshold value, there is some unevenness on the road surface of the detection range of the rear side sonars 2b and 2d by setting the rear threshold value high. Even if it does, it can suppress performing the false alerting | reporting that an obstruction exists by the presence of the unevenness | corrugation.

  Through the above processing, whether the rear threshold setting is “high setting” or “low setting” is periodically determined.

  Next, the reflected wave acquired from each sonar in S30 is compared with the threshold value for each sonar (S34). As a result of the comparison, when the magnitude of the reflected wave acquired from any one of the sonars is larger than the threshold value for the sonar, the user is notified that an obstacle exists (S35). On the other hand, if the magnitudes of the reflected waves acquired from the respective sonars are all smaller than the threshold value, no obstacle is present and the process proceeds to S36.

  In S36, it is determined whether or not the state in which the reflected waves of the front side sonars 2a and 2c do not exceed the front threshold value continues for a certain time (S36). If it is not determined that the reflected waves of the front side sonars 2a and 2c are larger than the front threshold value, the rear threshold value is set to “low setting” (S37). On the other hand, if the determination that the reflected waves of the front side sonars 2a and 2c are larger than the front threshold value is within the past fixed time, the threshold setting is not changed.

  When a large reflected wave is not received by the front side sonars 2a and 2c for a certain time or more, the front road surface is considered to be a road surface with small unevenness. In this case, even if the threshold value is lowered, the possibility that the road surface unevenness is erroneously detected as an obstacle is low, so the rear threshold value is set low so that even a small obstacle can be detected.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, The following embodiment is also contained in the technical scope of this invention, and also the summary other than the following is also included. Various modifications can be made without departing from the scope.

  For example, in the above-described first embodiment, the maximum intensity of the reception signals received by the front side sonars 2a and 2c is set as the rear threshold, but there are several other methods for setting the rear threshold. It is done.

  For example, you may set the average value of the reception signal acquired from front side sonar 2a, 2c for the fixed time as a rear threshold value. In addition, the reception signals of the front side sonars 2a and 2c reflect not only the road surface irregularities but also the obstacles within the detection range of the front side sonars 2a and 2c. It will be. Therefore, instead of setting the rear threshold for all the received signals for a certain period of time, the portion that can be clearly determined to be a signal due to an obstacle is excluded from the received signals for a certain period of time, and the rear threshold is set. It may be set. Whether the signal is caused by an obstacle is determined based on, for example, the fact that the reception signal exceeds the front threshold value by a predetermined value or more, or a predetermined ratio or more.

  In addition, if the predetermined time is extremely shortened, the waveform of the reflected wave received from the obstacle itself can be set as the rear threshold value. As described above, if the rear threshold value is set based on the reception signals of the front side sonars 2a and 2c, the rear threshold value may be set by various methods.

  Moreover, in this Embodiment, ECU1 is performing acquisition and notification of a detection result, However, Sonars may perform directly.

  In the present embodiment, four sonars are described. However, two or more sonars may be used as long as they are provided at the installation location described in FIG. The sensor may be a laser other than sonar.

DESCRIPTION OF SYMBOLS 1 Obstacle detection system, 2a Front side sonar (first side part sensor), 2b Rear side sonar (second side part sensor), 3 Alarm, 4 ECU, 5 Car body, 6 Front bumper side face, 7 Rear bumper side face, 8a Front detection range, 8b Rear detection range

Claims (4)

A first side surface sensor that is installed on the front side surface of the vehicle, transmits a signal wave toward a detection range on the front side of the vehicle, and receives a reflected wave in which the signal wave is reflected by an obstacle;
It is a rear side surface portion of the vehicle, and is installed on the same side surface as the first side surface portion sensor on the left and right side surfaces of the vehicle, transmits a signal wave toward a detection range on the rear side of the vehicle, and A second side surface sensor for receiving a reflected wave in which a signal wave is reflected by an obstacle;
Based on the intensity of the reflected wave received by the first side surface sensor and the first sensor threshold, the obstacle in the detection range in front is detected, and the intensity of the reflected wave received by the second side surface sensor and the first Obstacle detection means for detecting an obstacle in the detection range on the rear side based on a two-sensor threshold;
When the obstacle is detected by the obstacle detection means, a vehicle obstacle detection system comprising a notification unit for notifying that an obstacle has been detected,
The obstacle detection system for a vehicle, wherein the obstacle detection means sets the second sensor threshold based on a reflected wave of the first side surface sensor.   The obstacle detection system for a vehicle according to claim 1, wherein a maximum value of the intensity of the reflected wave received by the first side surface sensor for a certain period is sequentially set as the second sensor threshold value. The obstacle detection means includes
The second sensor threshold is set to one of a high threshold and a low threshold lower than the high threshold to detect an obstacle.
The vehicle obstacle according to claim 1, wherein the second sensor threshold is set to a high threshold based on the intensity of the reflected wave received by the first side surface sensor exceeding the first sensor threshold. Object detection system. When the second sensor threshold is a high threshold, the obstacle detection means is configured to detect the first sensor threshold when the intensity of the reflected wave received by the first side surface sensor does not exceed the first sensor threshold for a certain period. The vehicle obstacle detection system according to claim 3, wherein the two-sensor threshold value is changed to a low threshold value.

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