JP-7856548-B2 - Obstacle detection device

JP7856548B2JP 7856548 B2JP7856548 B2JP 7856548B2JP-7856548-B2

Inventors

深代優輝
永井秀幸
水谷厚司
加藤哲弥
片山雅之

Assignees

株式会社デンソー
トヨタ自動車株式会社
株式会社ミライズテクノロジーズ

Dates

Publication Date: 20260511
Application Date: 20221109

Claims (11)

Obstacle detection device (1) mounted on a vehicle, A transmitter (10A) that transmits a probe wave, At least one receiving unit (10B) is positioned differently from the transmitting unit and receives reflected waves generated when the probe wave is reflected by an object, A determination unit (53) determines a detectable distance from the vehicle's current position to the height of the obstacle, using a first threshold for reception intensity, which is determined according to the propagation time until the reflected wave reflected off the upper end of the obstacle is received, and data showing the time-series change in reception intensity of the road surface reflected wave among the reflected waves received by the receiving unit, and using the propagation time at which the reception intensity of the road surface reflected wave is equal to or greater than the first threshold, An obstacle detection unit (51) detects the distance to the obstacle based on the reflected wave received by the receiving unit, A height detection unit (53) for detecting the height of the obstacle, If the detected distance is less than or equal to the detectable distance, the receiving unit detects the height of the obstacle based on the reflected wave it has received. A height detection unit that does not detect the height of the obstacle when the detected distance is greater than the detectable distance, An obstacle detection device equipped with [a specific feature].
Obstacle detection device according to claim 1, The first threshold is set based on distance-dependent data that shows the relationship between the received intensity of the reflected wave reflected at the upper end of a pre-prepared obstacle and the distance to the pre-prepared obstacle. The determination unit finds one of the intersection points between the waveform representing continuous data on the time axis of the received intensity of the reflected wave received by the receiving unit and the waveform representing the first threshold, and uses the position on the time axis where the intersection point is located to determine the detectable distance at which the height of the obstacle can be detected. Obstacle detection device.
Obstacle detection device according to claim 2, The aforementioned pre-prepared obstacle is an object with a height that is assumed to be a wheel stop or curb. Obstacle detection device.
An obstacle detection device according to any one of claims 1 to 3, In a predetermined time interval after the transmission of the exploration wave, if the received intensity of the reflected wave received by the receiving unit exceeds a second threshold that is greater than the first threshold, The determination unit determines a detectable distance from the vehicle's current position to the height of the obstacle, using the first threshold and a first range of data showing the time-series change in the received intensity of the reflected wave received by the receiving unit, excluding at least the range in which the received intensity exceeds the second threshold. Obstacle detection device.
Obstacle detection device according to claim 4, A pulse signal is transmitted as the aforementioned exploration wave. The determination unit, when the waveform representing the time-series change in the received intensity of the reflected wave received by the receiving unit includes a maximum point, and the received intensity at the maximum point exceeds the second threshold, uses the range including the maximum point, excluding the pulse width range of the pulse signal, as the first range. Obstacle detection device.
Obstacle detection device according to claim 1, The transmitting unit and the receiving unit are, Both are located at the front end of the vehicle, or both are located at the rear end of the vehicle. In the vehicle width direction, on one side from the vehicle center, the following are arranged at different positions in the vehicle width direction: Obstacle detection device.
Obstacle detection device according to claim 1, It comprises a first pair of the transmitting unit and the receiving unit, and a second pair of the transmitting unit and the receiving unit, The first pair of transmitting units is positioned differently from the second pair of transmitting units. The receiving unit of the first pair is positioned differently from the receiving unit of the second pair. The receiving unit of the first pair receives the reflected wave generated by the reflection of the probe wave transmitted by the transmitting unit of the first pair. The receiving unit of the second pair receives the reflected wave generated by the reflection of the probe wave transmitted by the transmitting unit of the second pair. The aforementioned determination unit, For each of the receiving units, the detectable distance is calculated using the position on the time axis where the intersection point of the waveform representing the time-series change in the received intensity of the reflected wave and the waveform representing the first threshold is located. The average value of the detectable distance calculated for each of the aforementioned receiving units is determined. The height detection unit is If the detected distance is less than or equal to the average value of the detectable distance, the height of the obstacle is detected. If the detected distance is greater than the average value of the detectable distance, the height of the obstacle is not detected. Obstacle detection device.
An obstacle detection device according to claim 1, The receiving unit comprises two or more of the above-mentioned receiving units, Each of the aforementioned receiving units is: The transmitting unit and the other receiving units are located in different positions. The transmitting unit receives the reflected wave that is generated when the probe wave transmitted by the transmitting unit is reflected. The aforementioned determination unit, For each of the receiving units, the detectable distance is calculated using the position on the time axis where the intersection point of the waveform representing the time-series change in the received intensity of the reflected wave and the waveform representing the first threshold is located. The average value of the detectable distance calculated for each of the aforementioned receiving units is determined. The height detection unit detects the height of the obstacle when the detected distance is less than or equal to the average value of the detectable distances. If the detected distance is greater than the detectable distance, the height of the obstacle is not detected. Obstacle detection device.
Obstacle detection device according to claim 1, The transmitting unit transmits a pulse signal as the probe wave, and then, after a predetermined time has elapsed, transmits another pulse signal. The determination unit determines the intersection point between the waveform obtained by averaging the waveform of the reflected wave received earlier and the waveform of the reflected wave received later, and the waveform representing the first threshold, and uses the position on the time axis where the intersection point is located to determine the detectable distance. Obstacle detection device.
Obstacle detection device according to claim 3, An image sensor that photographs the upper end of the obstacle in the direction of travel of the vehicle and outputs image data, A storage unit that stores a first threshold value, which is set in advance for each size of the radius of curvature of the cross-section passing through the central position of the front and rear ends of the vehicle at the upper end of the obstacle, and data indicating the correspondence between the degree of brightness change of the image data output by the image sensor and the radius of curvature. Furthermore, The transmitting unit and the receiving unit are both located at the front end of the vehicle, or both are located at the rear end of the vehicle. The determination unit determines the detectable distance using the first threshold defined for each radius of curvature, which is determined from the degree of brightness change of the image data output by the image sensor. Obstacle detection device.
Obstacle detection device according to claim 1, It comprises a first pair of the transmitting unit and the receiving unit, and a second pair of the transmitting unit and the receiving unit, The first pair of transmitting units is positioned differently from the second pair of transmitting units. The receiving unit of the first pair is positioned differently from the receiving unit of the second pair. The first pair of transmitting units and receiving units, and the second pair of transmitting units and receiving units are arranged at the rear end of the vehicle. The first pair of transmitting and receiving units are arranged on one side of the vehicle center in the vehicle width direction, and the second pair of transmitting and receiving units are arranged on the other side of the vehicle center in the vehicle width direction. The aforementioned determination unit, When the vehicle is moving backward while turning, the detectable distance is determined using the propagation time obtained using data showing the time-series change in the received intensity of the road surface reflected wave included in the reflected wave received by the receiving unit located closer to the inner wheel of the vehicle among the first pair and the second pair, and the first threshold. Obstacle detection device.

Description

This disclosure relates to an obstacle detection device. In the technology described in Patent Document 1, an ultrasonic sensor installed on the vehicle is used to detect the height of obstacles surrounding the vehicle. Japanese Patent Publication No. 2021-38977 This diagram shows the positional relationship between a distance sensor mounted on a vehicle and an object.This is a block diagram illustrating the schematic configuration of an obstacle detection device.This is an explanatory diagram of the peak in the reflected wave received by the distance sensor.This is an explanatory diagram showing how to calculate the distance to an object and the height of the object.This is an explanatory diagram about reflected waves that occur when reflected by a tall obstacle.This figure shows an example of reflected waves, including road surface reflected waves.This is an explanatory diagram illustrating the advantages of placing ultrasonic sensors in different locations.This is a flowchart of the height calculation process.This is an explanatory diagram on how to identify the scope of exclusion.This is an explanatory diagram of the method for calculating the detectable distance.This is a cross-sectional view of the obstacle.This diagram shows an example of a vehicle equipped with two pairs of ultrasonic sensors.This diagram shows a vehicle moving while turning.This is an explanatory diagram of the control of vehicle A1 using the calculated detectable distance. A1. Embodiment The vehicle A1 shown in Figure 1 is equipped with a function to detect an object M1 in the vicinity of the vehicle A1. In Figure 1, a left-handed Cartesian coordinate system is set up with the X-axis being the direction parallel to the width direction of the vehicle A1, the Y-axis being the direction parallel to the front-rear direction of the vehicle A1, and the Z-axis being the direction parallel to the vertical direction. The rear of the vehicle A1 is defined as the positive Y-axis direction, and the vertically upward direction is defined as the positive Z-axis direction. In this embodiment, the assumed object M1 is a wheel stop composed of two blocks. Each block has a roughly rectangular parallelepiped shape extending in the X-axis direction. Note that one of the two blocks is located on the +X side of the other and is therefore not shown in Figure 1. In this embodiment, it is assumed that the object M1 is a low-height object. The object M1 is also called an obstacle. As shown in Figure 2, the obstacle detection device 1 comprises an injection unit 10A, a receiving unit 10B, a transmitting circuit 20, a receiving circuit 30, and a processing unit 50. As shown in Figure 1, the injection unit 10A and the receiving unit 10B are installed on the rear bumper of vehicle A1. The injection unit 10A and the receiving unit 10B are positioned at a distance from each other in the X-axis direction of vehicle A1. Note that the receiving unit 10B is positioned on the +X side of the injection unit 10A and is therefore not shown in Figure 1. Assume that the positions of the injection unit 10A and the receiving unit 10B are the same on the Y-axis and Z-axis. The ejection unit 10A and the receiving unit 10B are ultrasonic sensors using piezoelectric elements. The ejection unit 10A transmits ultrasonic waves as probe waves. For example, the ejection unit 10A transmits ultrasonic waves horizontally. The receiving unit 10B receives reflected waves that are reflected by objects around the vehicle A1. The ejection unit 10A is also called the transmitter. The receiving unit 10B is also called the receiver. In this embodiment, the ejection unit 10A is not used for receiving reflected waves. Also, the receiving unit 10B is not used for transmitting probe waves. The reason for using two ultrasonic sensors positioned at different locations for transmitting probe waves and receiving reflected waves will be explained later. As shown in Figure 2, the transmitting circuit 20 drives the ejection unit 10A according to the control of the processing unit 50, causing the ejection unit 10A to transmit ultrasonic waves at a preset frequency. The receiving circuit 30 supplies the processing unit 50 with a received signal indicating the reflected wave received by the receiving unit 10B. The ejection unit 10A, the receiving unit 10B, the transmitting circuit 20, and the receiving circuit 30 constitute the sonar system mounted on vehicle A1. The processing unit 50 detects the position and height of object M1 using the injection unit 10A and the receiving unit 10B. The processing unit 50 includes, as functional units, an obstacle detection unit 51, a height detection unit 53, and a storage unit 55. Each function of the processing unit 50 is implemented by a computer mounted on vehicle A1, which includes a processor, memory, etc. This computer can communicate with the ECU (Electronic Control Unit) of vehicle A1. The obstacle detection unit 51 determines whether or not there is an obstacle