JP2015210138A - Obstacle detection device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an obstacle detection device for vehicle which suppresses erroneous detection due to a secondary echo and multiple reflection waves when detecting an obstacle existing in the periphery of the own vehicle.SOLUTION: An ultrasonic sensor 102 emits an ultrasonic wave to the front side of the own vehicle and receives a reflection wave reflected by the obstacle. The signal of the received reflection wave is input to a sensing processing part 1032. A delay time measuring part 10321 detects the peak of the received signal and measures the delay time of the detected peak with the timing at which the ultrasonic sensor emits the ultrasonic wave as a reference. A multiple reflection determination part 10322 determines whether or not multiple reflection due to the obstacle occurs on the basis of the delay time of the peak. An obstacle determination part 10323 determines the presence/absence of the obstacle on the basis of the delay time of the peak and the determination result of the multiple reflection determination part 10322.

Description

  The present invention relates to an obstacle detection device for a vehicle that detects an obstacle present around the host vehicle.

In recent years, a number of vehicles equipped with a preventive safety system have emerged due to an increase in safety awareness of automobiles. These preventive safety systems use a camera / RADAR (Radio Detecting And Ranging) / LIDAR (Light) in order to detect vehicles / motorcycles / pedestrians around the vehicle (hereinafter, these objects are referred to as obstacles). Sensing equipment such as (Detecting And Ranging) / ultrasonic sensor is used.
As an obstacle detection method using the ultrasonic sensor, the ultrasonic wave periodically transmitted from the ultrasonic sensor is reflected by the obstacle, and the obstacle is based on the time difference (delay time) until the reflected wave is received. There is a method for detecting the distance up to. In this case, the maximum detectable distance depends on the ultrasonic transmission period. That is, the shorter the transmission cycle, the shorter the observation period until the next transmission cycle, and the shorter the maximum detectable distance.

In the method of periodically transmitting ultrasonic waves, a reflected wave from an obstacle located farther than the maximum detection distance of the ultrasonic sensor (hereinafter, this reflected wave is referred to as a secondary echo), or from the same obstacle Multiple reflected waves (reflected waves that have been reflected many times) cannot be received in the observation period, and ultrasonic waves may be received in the observation period after transmission in the next transmission period.
In such a case, if it is a secondary echo, an obstacle located far away will be erroneously detected as an obstacle located in the vicinity, and if it is a multiple reflected wave, a false image will be observed. Therefore, it becomes necessary to determine whether it is a fake image or an actual obstacle.
As a method for solving such a problem, Patent Document 1 discloses that a reflected wave to be detected and other reflected waves (multiple reflected waves) are distinguished from each other by changing an ultrasonic transmission cycle and an observation period. What to do is described.

Japanese Patent Laid-Open No. 10-104361 (pages 3 to 4, FIG. 2)

However, in the case of the technique of Patent Document 1, since it is necessary to change the transmission period and observation period of ultrasonic waves, the sensing process for detecting an obstacle becomes complicated.
Moreover, since the technique of patent document 1 recognizes the reflected wave received for the first time as the reflected wave from an obstacle unconditionally, there exists a problem that a secondary echo and a reflected wave cannot be distinguished.

  The present invention has been made in order to solve the above-described problems, and in detecting an obstacle existing around the host vehicle, the obstacle for a vehicle that suppresses erroneous detection due to a secondary echo or multiple reflected waves. The object is to obtain a detection device.

In the vehicle obstacle detection device according to the present invention, an obstacle detection device for a vehicle that detects an obstacle existing around the host vehicle, wherein the ultrasonic wave is configured to transmit and receive an ultrasonic signal. A sensor and a sensing processing unit that detects an obstacle existing around the vehicle from the ultrasonic signal received by the ultrasonic sensor, and the sensing processing unit includes a peak of the ultrasonic signal received by the ultrasonic sensor. Based on the delay time measurement unit that measures the delay time of the detected peak on the basis of the timing at which the ultrasonic sensor transmits the ultrasonic signal, and the peak delay time measured by this delay time measurement unit A multiple reflection determination unit for determining whether or not multiple reflections due to an obstacle have occurred, a peak delay time measured by the delay time measurement unit, and a multiple reflection determination unit Based on the constant results, and has a determining obstacle determining unit the presence or absence of obstacles.

  According to the present invention, an obstacle detection device for a vehicle that detects an obstacle existing around the host vehicle, the ultrasonic sensor configured to transmit and receive an ultrasonic signal, and the ultrasonic sensor A sensing processing unit that detects obstacles existing around the host vehicle from the ultrasonic signal received by the sensor, the sensing processing unit detects a peak of the ultrasonic signal received by the ultrasonic sensor, and the ultrasonic sensor Based on the timing at which the ultrasonic signal is transmitted, the delay time measurement unit that measures the delay time of the detected peak, and the multiple reflections by the obstacle based on the peak delay time measured by the delay time measurement unit. The presence of an obstacle is determined based on the multiple reflection determination unit that determines whether or not it has occurred, the peak delay time measured by the delay time measurement unit, and the determination result of the multiple reflection determination unit. Because it has a determining obstacle determining unit whether a, it is possible to suppress erroneous detection due to multiple reflected waves.

It is a block diagram which shows the structure of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a figure which shows the timing of the transmission signal and reception signal of the ultrasonic wave of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a figure which shows the vehicle-mounted arrangement | positioning of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is an image figure showing the false detection by the secondary echo of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a flowchart which shows the process of the sensing process part of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a flowchart which shows the process of the delay time measurement part of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a flowchart which shows the process of the multiple reflection determination part of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a flowchart which shows the process of the obstacle determination part of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention. It is a figure showing the propagation condition of an ultrasonic wave in case the false image which appears by the secondary echo of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention and an actual vehicle are the same positions. It is a figure which shows the timing of the transmission signal and reception signal of an ultrasonic wave in case the false image which appears with the secondary echo of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention and an actual vehicle are the same positions. It is a figure showing the propagation condition of an ultrasonic wave when the multiple reflection of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention has generate | occur | produced. It is a figure which shows the timing of the transmission signal and reception signal of an ultrasonic wave in case the multiple reflection of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention has generate | occur | produced. It is a figure which shows the timing of the transmission signal and reception signal of an ultrasonic wave in case the false detection of the peak by the noise of the obstacle detection apparatus for vehicles by Embodiment 1 of this invention has generate | occur | produced.

Embodiment 1 FIG.
[Constitution]
1 is a block diagram showing a configuration of a vehicle obstacle detection device according to Embodiment 1 of the present invention.
In FIG. 1, the vehicle obstacle detection device according to the first embodiment includes an ultrasonic sensor ECU 10, a brake control ECU 11, and a CAN communication line 12 that are on-vehicle equipment. The ultrasonic sensor ECU 10 and the brake control ECU 11 are connected via the CAN communication line 12, and the respective ECUs can communicate with each other by using the communication means 101 and 111, respectively.

The ultrasonic sensor ECU 10 includes an ultrasonic sensor 102 and a microcomputer 103.
The ultrasonic sensor 102 boosts the ultrasonic drive instruction signal input from the microcomputer 103 and converts it into a drive pulse voltage. The ultrasonic sensor 102 electrically excites the drive pulse voltage, and converts it into mechanical vibration by a piezoelectric element. The ultrasonic transducer unit 1021 that radiates ultrasonic waves to the space, and the electric signal in which the emitted ultrasonic wave is reflected by the obstacle and the reflected wave that has arrived at the ultrasonic transducer unit 1021 is converted by the piezoelectric element. An AMP unit 1023 that amplifies (ultrasonic signal) voltage, and a filter unit 1024 that filters the output of the AMP unit 1023 and inputs it to the microcomputer 103.

  On the other hand, the microcomputer 103 converts an analog signal input from the ultrasonic sensor 102 into a digital signal, and a received signal (ultrasonic signal) converted into a digital signal by the A / D converter 1031. And a sensing processing unit 1032 for detecting an obstacle and a vehicle control unit 1033.

The sensing processing unit 1032 is configured as follows in order to determine an obstacle from the reflected wave.
The delay time measurement unit 10321 detects a peak from the reception signal converted into a digital signal by the A / D conversion unit 1031 and measures a time difference (delay time) of the detected peak with reference to the ultrasonic transmission timing. . The multiple reflection determination unit 10322 determines whether multiple reflection has occurred based on the peak delay time measured by the delay time measurement unit 10321. The obstacle determination unit 10323 selects the reflected wave of the obstacle to be detected based on the delay time of the delay time measurement unit 10321 and the occurrence information of multiple reflection waves of the multiple reflection determination unit 10322, and the obstacle determination unit 10323 Calculate the distance.

  The vehicle control unit 1033 determines the possibility of a collision with the preceding vehicle based on the processing result of the obstacle determination unit 10323, and determines that there is a possibility of a collision, the brake control ECU 11 via the communication unit 101. The brake instruction is given to.

FIG. 2 is a diagram showing timings of ultrasonic transmission signals and reception signals of the vehicle obstacle detection device according to Embodiment 1 of the present invention.
FIG. 2A is a diagram illustrating timings of ultrasonic transmission signals and reception signals, and periodically transmits transmission signals. The reflected wave from the obstacle is received as a received signal within the observation period with the transmission period as an observation period.
FIG. 2B is a diagram showing timings of ultrasonic transmission signals and reception signals with respect to an obstacle located farther than the maximum detection distance, and reflection from an obstacle located farther than the maximum detection distance. A wave (secondary echo) is received in the next observation period.
That is, the reflected wave A by the transmission A is received not in the observation period A but in the observation period B, and an obstacle located far away is erroneously detected as an obstacle located in the vicinity.
FIG. 2C is a diagram showing the timing of the ultrasonic transmission signal and the reception signal when multiple reflection occurs, and when multiple reflected waves from the same obstacle are received in the next observation period. Is shown.
That is, the multiple reflected wave A ′ by the transmission A and the reflected wave B by the transmission B are received in the observation period B, and it is determined whether the multiple reflected wave A ′ or the reflected wave B is an obstacle to be detected. If you need to do that.

FIG. 3 is a diagram showing an on-vehicle arrangement of the vehicle obstacle detection device according to Embodiment 1 of the present invention.
In FIG. 3, an ultrasonic sensor ECU 10 that is a vehicle obstacle detection device is mounted on the front portion of the host vehicle 1 in order to detect the preceding vehicle 2. It is assumed that a horn 14 is loaded on the ultrasonic sensor ECU 10. Thereby, since the ultrasonic radiation pattern 3 of the ultrasonic sensor ECU 10 is narrowed in the front direction by the horn 14, the preceding vehicle 2 can be detected at a far point.

FIG. 4 is an image diagram showing erroneous detection by secondary echo of the vehicle obstacle detection device according to Embodiment 1 of the present invention.
In FIG. 4, 1-3, 10, and 14 are the same as those in FIG. FIG. 4 shows a false image vehicle 2 ′ that erroneously detects the preceding vehicle 2 that is originally located far away.

FIG. 9 is a diagram showing an ultrasonic wave propagation state in the case where the false image appearing by the secondary echo of the vehicle obstacle detection device according to Embodiment 1 of the present invention and the actual vehicle are at the same position.
In FIG. 9, 1-3, 10, 14, 2 ′ are the same as those in FIG.
The false image vehicle 2 ′ by the secondary echo in FIG. 9A and the actual preceding vehicle 2 in FIG. 9B are at the same position with respect to the host vehicle 1.

FIG. 10 shows the timing of the ultrasonic transmission signal and reception signal when the false image appearing by the secondary echo of the vehicle obstacle detection device according to Embodiment 1 of the present invention and the actual vehicle are at the same position. FIG.
FIG. 10A is a diagram showing a timing relationship between the ultrasonic transmission signal and the reception signal in FIG. 9A, and FIG. 10B is a diagram of the ultrasonic transmission signal and the reception signal in FIG. 9B. It is a figure which shows a timing relationship.

FIG. 11 is a diagram illustrating an ultrasonic wave propagation state when multiple reflections occur in the vehicle obstacle detection device according to Embodiment 1 of the present invention.
In FIG. 11, 1-3, 10, and 14 are the same as those in FIG. In FIG. 11, multiple reflections occur between the host vehicle 1 and the preceding vehicle 2.

FIG. 12 is a diagram showing timings of ultrasonic transmission signals and reception signals when multiple reflections occur in the vehicle obstacle detection device according to Embodiment 1 of the present invention.
FIG. 12 shows the timing relationship between the ultrasonic transmission signal and the reception signal in a situation where multiple reflection occurs between the host vehicle 1 and the preceding vehicle 2 in FIG.

FIG. 13 is a diagram showing timings of ultrasonic transmission signals and reception signals when an erroneous peak detection due to noise occurs in the vehicle obstacle detection device according to Embodiment 1 of the present invention.
FIG. 13 shows a timing relationship between an ultrasonic transmission signal and a reception signal in a situation where multiple reflection occurs between the host vehicle 1 and the preceding vehicle 2 in FIG. 9B. 10 (b) is an enlarged view of observation period A, but is different by one point, and noise N is detected as a peak at the delay time: T_noise.

Next, the operation will be described.
When an ultrasonic drive instruction signal is input from the microcomputer 103 to the ultrasonic sensor 102, the ultrasonic drive instruction signal is boosted by the transformer unit 1022 and converted into a drive pulse voltage. As a result, when the drive pulse voltage is input to the ultrasonic transducer unit 1021, the ultrasonic transducer unit 1021 is electrically excited and converted into mechanical vibration by the piezoelectric element in the ultrasonic transducer unit 1021. On the other hand, ultrasonic waves are emitted.
The ultrasonic wave propagated through the space is reflected by the obstacle, and the reflected wave arrives at the ultrasonic transducer unit 1021 as an obstacle echo.
This reflected wave is again converted into an electric signal by the piezoelectric element in the ultrasonic transducer unit 1021, voltage amplified by the AMP unit 1023 as a reception signal, and input to the microcomputer 103 via the filter unit 1024.

A received signal (analog signal) input to the microcomputer 103 is digitally converted by the A / D converter 1031 and then used by the sensing processor 1032 in the microcomputer 103 to detect an obstacle.
In the sensing processing unit 1032, a peak is detected from the reception signal converted into a digital signal by the A / D conversion unit 1031, and a time difference (delay time) of the detected peak with reference to the ultrasonic transmission timing is determined as a delay time measurement unit. Measure according to 10321.
Based on the peak delay time measured by the delay time measurement unit 10321, the multiple reflection determination unit 10322 determines whether multiple reflection has occurred.
Based on the delay time of the delay time measuring unit 10321 and the information on whether multiple reflected waves are generated by the multiple reflection determining unit 10322, the obstacle determining unit 10323 selects the reflected wave of the obstacle to be detected, and the obstacle The distance to is calculated.

  Next, the vehicle control unit 1033 determines the possibility of a collision with the preceding vehicle based on the processing result of the obstacle determination unit 10323. If it is determined that there is a possibility of a collision, the brake control is performed via the communication unit 101. A brake instruction is given to the ECU 11.

By the way, as shown in FIG. 3, by narrowing the radiation pattern 3 with the horn 14, an obstacle can be detected at a farther point, while secondary echoes and multiple reflected waves are easily generated.
FIG. 3 shows a situation where secondary echo is occurring. As shown in FIG. 3, since the preceding vehicle 2 is located farther than the maximum detection distance in one observation period, the reflected wave from the preceding vehicle 2 is 2 in the next observation period in which the ultrasonic wave is transmitted. It is received as the next echo (the transmission / reception timing of the ultrasonic wave is the same as in FIG. 2B).
That is, as shown in FIG. 4, the preceding vehicle 2 that is originally located far away is erroneously detected as a false image vehicle 2 ′. As a result, although there is no possibility of collision, brake control is performed.

In such a situation, if the erroneous detection suppression method in the first embodiment is used, erroneous detection of the preceding vehicle 2 can be suppressed.
Hereinafter, the flow of each process of the sensing processing unit 1032 will be sequentially described with reference to flowcharts of the respective processing units in FIGS.

[Processing flow]
First, a rough processing flow of the sensing processing unit 1032 will be described with reference to FIG.
The activation timing of the sensing processing unit 1032 is assumed to be activated after the A / D conversion unit 1031 has converted all ultrasonic reception signals within one observation period into digital signals.
When activated, the sensing processing unit 1032 measures the delay time of the ultrasonic reception signal (step S10321). Details of the processing content of step S10321 will be described later. After step S10321 is completed, the process proceeds to step S10322.

In step S10322, it is determined whether multiple reflection has occurred based on the delay time measurement result in step S10321. Details of the processing content of step S10322 will be described later. After step S10322 is completed, the process proceeds to step S10323.
In step S10323, based on the delay time measurement result in step S10321 and the multiple reflection determination result in step S10322, it is determined whether there is an obstacle to be detected, and the distance to the obstacle is calculated. Details of the processing content of step S10323 will be described later.
After the completion of step S10323, the processing of the sensing processing unit 1032 is terminated.

Next, the processing flow of the delay time measurement unit 10321 of the sensing processing unit 1032 will be described with reference to FIG.
First, a peak is detected from the received ultrasonic reception signal (digitalized) (step S103211). After step S103211 is completed, the process proceeds to step S103212.
In step S103212, the delay time of the detected peak is measured based on the peak detection result in step S103211. After step S103212 is completed, the processing of the delay time measurement unit 10321 is terminated.

Next, the processing flow of the multiple reflection determination unit 10322 of the sensing processing unit 1032 will be described with reference to FIG.
First, based on the peak detection result of the delay time measurement unit 10321, it is determined whether or not there is a peak in the ultrasonic reception signal (step S103221). If there is a peak, the process proceeds to step S103222. If there is no peak, it is determined that there is no obstacle to be detected, and the processing of the multiple reflection determination unit 10322 is terminated.

In consideration of the case where the delay time measuring unit 10321 detects a plurality of peaks, the role of the reference peak is assigned in order from the first peak (the peak with the short delay time). Therefore, in step S103222, it is determined whether there is a peak not selected as the reference peak.
If there is a peak that is not selected as the reference peak, the process proceeds to step S103223. If there is no peak that is not selected as the reference peak, the processing of the multiple reflection determination unit 10322 is terminated.

In step S103223, based on the determination result in step S103222, the peak: P_k is selected as the reference peak: P_Std_k. After the selection of the reference peak is completed, the process proceeds to step S103224.
In step S103224, it is determined whether multiple reflection has occurred based on the reference peak P_Std_k delay time T_Std_k selected in step S103223.
Specifically, it is determined whether or not there is a peak P_i having a delay time T_i in the vicinity of the reference peak P_Std_k delay time T_Std_k multiplied by an integer: M (integer) × T_Std_k. If there is a peak P_i satisfying this condition, the process proceeds to step S103225. If a peak P_i satisfying this condition does not exist, the process proceeds to step S103227.

In step S103225, the peak: P_i that satisfies the condition of step S103224 is determined as the multiple reflected wave: MPR_k of the reference peak: P_Std_k. After completion of the determination of multiple reflected waves, the process proceeds to step S103226.
In step S103226, the number of MPR_k_cnt that has been determined as the multiple reflected wave MPR_k of the reference peak P_Std_k in step S103225 is counted. After completion of counting the number of multiple reflected waves, the process proceeds to step S103227.
In step S103227, the reference peak is updated to the next peak: P_k + 1, assuming that the multiple reflected wave determination process for the reference peak: P_Std_k (peak: P_k) is completed. After the peak update is completed, the process returns to step S103222.

Next, a processing flow of the obstacle determination unit 10323 of the sensing processing unit 1032 will be described with reference to FIG.
First, based on the peak detection result of the delay time measurement unit 10321, it is determined whether or not there is a peak in the received ultrasonic wave reception signal (step S103231). If there is a peak, the process proceeds to step S103232. If no peak is present, the process proceeds to step S103233, where it is determined that there is no obstacle to be detected, and the processing of the obstacle determination unit 10323 is terminated.

In step S103232, it is determined whether or not there is a peak: P_i whose delay time: T_i is less than or equal to half of the observation period: T_obsv. If there is a peak: P_i in which the delay time: T_i is equal to or less than half of the observation period: T_obsv, it can be determined whether or not secondary echoes and multiple reflected waves are included in the received ultrasonic signal. The process proceeds to step S103234.
Delay time: T_i is less than half of the observation period: T_obsv If there is no peak: P_i, it cannot be determined whether secondary echo or multiple reflected waves are included in the ultrasonic reception signal The process proceeds to step S103237.

  In step S103234, it is determined whether or not there is a multiple reflected wave MPR_i corresponding to the peak: P_i, which is a delay time equal to or less than half of the observation period: T_obsv. Observation period: When there is a multiple reflected wave MPR_i corresponding to a peak: P_i that is a delay time equal to or less than half of T_obsv, since the peak: P_i is a reflected wave from an obstacle, the process proceeds to step S103235. Observation period: When the multiple reflected wave MPR_i corresponding to the peak: P_i, which is a delay time equal to or less than half of T_obsv, does not exist, the peak: P_i is a secondary echo or multiple reflected wave, so the process proceeds to step S103236.

  In step S103235, considering the case where a plurality of peaks in which multiple reflected waves exist are detected, the peak having the maximum number of multiple reflected waves: MPR_i_cnt: P_i is determined as a reflected wave from the obstacle (determined), and the obstacle Calculate the distance to (confirm). After calculating the distance to the obstacle (determined), the processing of the obstacle determination unit 10323 is terminated.

  In step S103236, the peak: P_i, which is a delay time equal to or less than half of the observation period: T_obsv in which no multiple reflected wave exists, is determined as a secondary echo or multiple reflected wave, and the peak is determined not to be an obstacle. After step S103236 is completed, the process proceeds to step S103237.

  In step S103237, since it is not possible to determine whether the reflected wave is from the obstacle or the secondary echo / multiple reflected wave at the present time, the peak: P_i, which is a delay time exceeding half of the observation period: T_obsv, is determined from the obstacle (undefined). And the distance to the obstacle (undefined) is calculated. After calculating the distance to the obstacle (unconfirmed), the processing of the obstacle determination unit 10323 is terminated.

[Effect of Embodiment 1]
The effect of suppressing erroneous detection by the secondary echo according to the first embodiment will be described with reference to FIGS.
FIG. 9A shows the propagation state of the false image and the ultrasonic wave that can be seen by the secondary echo, and FIG. 9B shows the case where an actual vehicle is present at the same position as the false image of FIG. It is a figure showing the propagation condition of an ultrasonic wave.
10A shows the timing relationship between the ultrasonic transmission signal and the reception signal in FIG. 9A, and FIG. 10B shows the timing relationship between the ultrasonic transmission signal and the reception signal in FIG. 9B. Represents.

Here, in FIG. 9A, it is assumed that multiple reflection does not occur because the positional relationship between the host vehicle 1 and the preceding vehicle 2 is far. On the other hand, in FIG. 9B, it is assumed that multiple reflection occurs because the positional relationship between the host vehicle 1 and the preceding vehicle 2 is close.
In FIG. 10B, the delay time T_A (T_B, T_C) of the reflected wave A1 (B1, C1) is set to be equal to or less than one-fourth of the observation period T_obsv.
That is, in the situation shown in FIG. 9B and FIG. 10B, the transmission A (B, C1) is transmitted around the delay time of the reflected wave A1 (B1, C1): T_A (T_B, T_C) multiplied by an integer. C) multiple reflected waves A2, A3 (B2, B3, C2, C3) are observed.

  On the other hand, when a false image is erroneously detected by the secondary echo shown in FIGS. 9A and 10A, the delay time of the reflected wave A in the observation period B: around the time obtained by multiplying T_B ′ by an integer, There are no multiple reflected waves. Therefore, the reflected wave A received in the observation period B is determined not to be a reflected wave due to the transmission B, and is not detected as an obstacle.

Next, the effect of suppressing erroneous detection due to multiple reflected waves according to the first embodiment will be described with reference to FIGS.
FIG. 11 shows a situation in which multiple reflection occurs between the host vehicle 1 and the preceding vehicle 2. The timing relationship between the ultrasonic transmission signal and the reception signal in this situation is as shown in FIG.
In FIG. 12, the delay time: T_A1 (T_B1, T_C1) of the reflected wave A1 (B1, C1) is set to be not less than half of the observation period: T_obsv and not more than three-quarters. Further, since the reflected wave B2 (C2) is a multiple reflected wave: A ′ (B ′) in the transmission A (B), the delay time of the reflected wave B2 (C2): T_B2 (T_C2) is half of the observation period: T_obsv. It becomes as follows.

From FIG. 12, although two reflected waves B1 and reflected wave B2 are received in observation period B, it cannot be determined which of these observation results is a reflected wave from an obstacle to be detected. Therefore, according to the first embodiment, it is determined whether or not multiple reflected waves are included in the received reflected waves.
First, it is determined whether or not the delay time of each reflected wave is equal to or less than half of the observation period: T_obsv. In this case, the delay time T_B2 of the reflected wave B2 is less than or equal to half of the observation period T_obsv.
Observation period: When it is assumed that the reflected wave B2 having a delay time of half or less of T_obsv is a reflected wave returned from the obstacle by the transmission B, the delay time of the reflected wave B2 is around the time obtained by multiplying T_B2 by an integer. , Multiple reflected waves of transmission B should be observed.
However, the multiple reflected waves of the transmission B are not observed before and after the delay time of the reflected wave B2: a time obtained by multiplying T_B2 by an integer. Therefore, the reflected wave B2 is determined not to be a reflected wave by the transmission B, and is not recognized as an obstacle.

  On the other hand, regarding the reflected wave B1, since the delay time T_B1 of the reflected wave B1 is longer than half of the observation period T_obsv, it cannot be determined at this time whether or not it is a reflected wave from an obstacle by the transmission B. Therefore, considering the possibility that the reflected wave B1 is a reflected wave from the transmission B, it is recognized as an undetermined obstacle.

Furthermore, the effect of suppressing erroneous detection due to noise or the like according to Embodiment 1 will be described with reference to FIG.
FIG. 13 shows the timing relationship between the ultrasonic transmission signal and the reception signal under the situation where multiple reflection occurs between the host vehicle 1 and the preceding vehicle 2 as shown in FIG. 9B. Is.
FIG. 13 is an enlarged view of the observation period A in FIG. 10B, and basically shows the same situation. However, only one point is different, and the noise N is detected as a peak at the delay time: T_noise.
Here, the delay time of the noise N: T_noise is any one of the delay time of the reflected wave A1: half of the T_A, or the delay time of the reflected wave A1: 1.5 times the T_A and the observation period: less than half of the T_obsv Is not satisfied, since the reflected wave and the multiple reflected wave of the transmission A are not observed before and after the delay time of the noise N: T_noise multiplied by an integer, the noise N is not erroneously detected as an obstacle.

  However, the delay time of the noise N: T_noise is one of the following conditions: the delay time of the reflected wave A1: half of the T_A, or the delay time of the reflected wave A1: 1.5 times the T_A and the observation period: less than half of the T_obsv Is satisfied, since the reflected wave and the multiple reflected wave of the transmission A are observed before and after the delay time of the noise N: T_noise multiplied by an integer, the noise N is erroneously detected as an obstacle.

Therefore, using the number of multiple reflected waves of each peak: MPR_i_cnt, a peak that is most likely to be an obstacle is selected from a plurality of peaks detected as an obstacle.
From FIG. 13, the peaks detected as obstacles are the reflected wave A1 and noise N. The multiple reflected waves A2 and A3 are not detected as obstacles because the corresponding multiple reflected waves are not observed when each is used as a reference peak.

When the number of the multiple reflected waves corresponding to the reflected wave A1 and the noise N is counted, the number of the multiple reflected waves of the reflected wave A1 is two (the multiple reflected waves A2 and A3), and the number of the multiple reflected waves of the noise N is one. (Multiple reflected wave A3).
Therefore, since the reflected wave A1 is more likely to be an obstacle than the noise N, the reflected wave A1 is determined to be a reflected wave from the obstacle by the transmission A and detected as an obstacle.

As described above, according to the vehicle obstacle detection device of the first embodiment, multiple reflected waves are included in the received signal based on the peak delay time detected from the received ultrasonic signal received in the same observation period. It is determined whether or not it is included, and the number of peaks determined as multiple reflected waves is counted.
Thereby, it is possible to suppress erroneous detection due to secondary echoes, multiple reflected waves, or the like without changing the ultrasonic transmission cycle or observation period.

  In the present invention, the embodiments can be appropriately modified and omitted within the scope of the invention.

1 own vehicle, 2 preceding vehicle, 3 radiation pattern, 10 ultrasonic sensor ECU,
11 brake control ECU, 12 CAN communication line, 14 horn,
101, 111 communication means, 102 ultrasonic sensor, 103 microcomputer,
1021 Ultrasonic transducer part, 1022 transformer part, 1023 AMP part,
1024 filter unit, 1031 A / D conversion unit, 1032 sensing processing unit,
1033 Vehicle control unit, 10321 delay time measurement unit, 10322 multiple reflection determination unit,
10323 An obstacle determination unit.

In the vehicle obstacle detection device according to the present invention, an obstacle detection device for a vehicle that detects an obstacle existing around the host vehicle, wherein the ultrasonic wave is configured to transmit and receive an ultrasonic signal. A sensor and a sensing processing unit that detects an obstacle existing around the vehicle from the ultrasonic signal received by the ultrasonic sensor, and the sensing processing unit includes a peak of the ultrasonic signal received by the ultrasonic sensor. Based on the delay time measurement unit that measures the delay time of the detected peak on the basis of the timing at which the ultrasonic sensor transmits the ultrasonic signal, and the peak delay time measured by this delay time measurement unit A multiple reflection determination unit for determining whether or not multiple reflections due to an obstacle have occurred, a peak delay time measured by the delay time measurement unit, and a multiple reflection determination unit Based on the constant result, possess a determining obstacle determining unit the presence or absence of an obstacle, the multiple reflection judgment unit, for each peak measured by the delay time measuring unit, the ascending order of the delay time, the peak When there are a plurality of peaks received after the peak before and after the time obtained by multiplying the delay time by an integer, the plurality of peaks received later are determined as multiple reflected waves and a process of counting the number of multiple reflected waves is performed. The obstacle determination unit determines whether there is an obstacle based on the delay time of each peak measured by the delay time measurement unit, the information of the multiple reflected waves determined by the multiple reflection determination unit, and the number of multiple reflected waves. If there is an obstacle, the distance to the obstacle is calculated .

According to the present invention, an obstacle detection device for a vehicle that detects an obstacle existing around the host vehicle, the ultrasonic sensor configured to transmit and receive an ultrasonic signal, and the ultrasonic sensor A sensing processing unit that detects obstacles existing around the host vehicle from the ultrasonic signal received by the sensor, the sensing processing unit detects a peak of the ultrasonic signal received by the ultrasonic sensor, and the ultrasonic sensor Based on the timing at which the ultrasonic signal is transmitted, the delay time measurement unit that measures the delay time of the detected peak, and the multiple reflections by the obstacle based on the peak delay time measured by the delay time measurement unit. The presence of an obstacle is determined based on the multiple reflection determination unit that determines whether or not it has occurred, the peak delay time measured by the delay time measurement unit, and the determination result of the multiple reflection determination unit. Possess the obstacle determining unit determines the presence or absence of multiple reflection judgment unit, for each peak measured by the delay time measuring unit, the ascending order of the delay time, before and after the delay time of the peak integral multiple the time When there are a plurality of peaks received after the peak, the plurality of peaks received later are determined to be multiple reflected waves and the number of multiple reflected waves is counted. The obstacle determination unit is a delay time measurement unit. If there is an obstacle, the presence or absence of an obstacle is determined based on the delay time of each peak measured by the above, and the information of the multiple reflected waves determined by the multiple reflection determination unit and the number of multiple reflected waves Calculates the distance to the obstacle, so that erroneous detection due to multiple reflected waves can be suppressed.

Claims (3)

An obstacle detection device for a vehicle that detects obstacles around the host vehicle,
An ultrasonic sensor configured to transmit and receive ultrasonic signals;
And a sensing processing unit for detecting an obstacle existing around the own vehicle from the ultrasonic signal received by the ultrasonic sensor,
The sensing processing unit
A delay time measuring unit that detects a peak of the ultrasonic signal received by the ultrasonic sensor and measures the delay time of the detected peak with reference to a timing at which the ultrasonic sensor transmits the ultrasonic signal;
Based on the delay time of the peak measured by the delay time measurement unit, a multiple reflection determination unit that determines whether multiple reflections due to the obstacle have occurred,
The vehicle has an obstacle determination unit that determines the presence or absence of an obstacle based on the delay time of the peak measured by the delay time measurement unit and the determination result of the multiple reflection determination unit. Obstacle detection device. In the multiple reflection determination unit, for each peak measured by the delay time measurement unit, there are peaks received after the peak around the time obtained by multiplying the delay time of the peak by an integer in order of increasing delay time. In such a case, the peak received after the above process is determined as a multiple reflected wave,
The obstacle determination unit
Based on the delay time of each peak measured by the delay time measurement unit and the information of the multiple reflected wave determined by the multiple reflection determination unit, the presence / absence of an obstacle is determined, and the obstacle exists The vehicle obstacle detection device according to claim 1, wherein a distance to the obstacle is calculated when the obstacle is to be detected. The multiple reflection determination unit includes, for each peak measured by the delay time measurement unit, a plurality of peaks received after the peak around the time obtained by multiplying the peak delay time by an integer in order of increasing delay time. In the case of performing the process of determining the plurality of peaks received later as multiple reflected waves and counting the number of the multiple reflected waves,
The obstacle determination unit
Based on the delay time of each peak measured by the delay time measurement unit, the information on the multiple reflection waves determined by the multiple reflection determination unit, and the number of multiple reflection waves, the presence or absence of an obstacle is determined. The vehicle obstacle detection device according to claim 1, wherein the vehicle obstacle detection device determines and calculates a distance to the obstacle when an obstacle is present.