JP7706433B2 - Driving Support Devices - Google Patents

Description

The present invention relates to a driving assistance device that assists in driving a vehicle.

Conventionally, there is technology for vehicles (such as passenger cars) to detect targets (other vehicles, pedestrians, etc.) around the vehicle based on sensor data (such as camera image data), and when the target enters a specified area that includes the planned driving route, calculate the collision risk based on the relative speed of the target with respect to the vehicle.

JP 2022-113974 A

In the above-mentioned conventional technology, the amount of movement of the target after it enters a predetermined area including the planned travel route is calculated, and the relative speed of the target is calculated based on the amount of movement. Therefore, it takes time to calculate the collision risk, and there is a problem that a situation may arise where a collision between the vehicle and the target cannot be avoided by the time the collision risk is calculated.

The objective of the present invention is to provide a driving assistance device that can reduce the risk of collision between the vehicle and a target.

In order to solve the above-mentioned problems, the driving assistance device of the present invention includes an acquisition unit that acquires target information, which is information on targets present around the vehicle, from a predetermined sensor; a determination unit that determines whether the target is present in an outer area, which is an area outside a predetermined area including the planned driving route of the vehicle, based on the target information; a detection unit that detects the target in the predetermined area based on the target information; and a calculation unit that calculates a collision risk based on the relative speed of the target with respect to the vehicle when the detection unit detects the target in the predetermined area.

With this configuration, the collision risk is calculated based on the relative speed of the target to the vehicle immediately after the target enters the specified area, thereby reducing the risk of collision between the vehicle and the target.

In addition, when the host vehicle is traveling, the specified area is defined by a length in the direction of movement corresponding to the vehicle speed of the host vehicle and a length in the vehicle width direction of the host vehicle corresponding to the distance from the host vehicle in the direction of movement, and when the detection unit detects the target in the specified area, the calculation unit calculates the collision risk based on a value obtained by adding a specified relative speed to the relative speed of the target with respect to the host vehicle.

With this configuration, the risk of collision between the vehicle and the target can be further reduced by calculating the collision risk based on the value obtained by adding a predetermined relative speed to the relative speed of the target with respect to the vehicle.

According to the present invention, the collision risk is calculated based on the relative speed of the target to the vehicle immediately after the target enters a specified area, thereby reducing the risk of collision between the vehicle and the target.

FIG. 1 is a block diagram showing the configuration of a driving assistance system according to the first embodiment. FIG. 2 is a diagram showing an example of the positional relationship between the host vehicle and a target in the first embodiment. FIG. 3 is a flowchart showing a process performed by the driving assistance system of the first embodiment. FIG. 4 is a flowchart showing a process performed by the driving assistance system of the second embodiment.

Below, an embodiment of a driving assistance system including a driving assistance device of the present invention will be described with reference to the attached drawings.

Figure 1 is a block diagram showing the configuration of a driving assistance system 1 of the first embodiment. The driving assistance system 1 is a system that is installed in a host vehicle C1 (Figure 2) and assists a driver in driving the host vehicle C1. The driving assistance system 1 has a collision warning function, a primary braking function (gentle braking function), and a secondary braking function (hard braking function) as driving assistance functions for avoiding a collision between the host vehicle C1 and an object (such as other vehicles C2, C3, or pedestrian M in Figure 2) or reducing damage caused by the collision.

The collision warning function uses an alarm 26 (described in detail later) to warn (notify) the driver of the possibility of a collision. The primary braking function uses automatic braking to decelerate the host vehicle C1 at a primary target deceleration in order to encourage the driver to take action to avoid the collision. The secondary braking function uses automatic braking to decelerate the host vehicle C1 at a secondary target deceleration that is greater than the primary target deceleration in order to avoid the collision and reduce the damage caused by the collision.

The driving assistance system 1 includes an ECU (Electronic Control Unit) 11. The ECU 11 is equipped with a microcomputer (microcontroller) 12. The microcomputer 12 has a built-in CPU 13 and memory 14. In addition to the ECU 11, the vehicle C1 is equipped with multiple ECUs for controlling various parts, and the ECU 11 is connected to the other ECUs so that bidirectional communication is possible using a CAN (Controller Area Network) communication protocol.

The vehicle C1 is also equipped with a camera 21 (an example of a predetermined sensor). The camera 21 is, for example, a stereo camera capable of continuously capturing still images at a predetermined frame rate. The camera 21 is installed in a position that allows it to capture images of the surroundings of the vehicle C1 at a wide angle. For example, four cameras 21 are installed so that each camera captures images of the front, rear, left, and right of the vehicle C1.

For example, camera 21 extracts target pixels corresponding to the same object in each image captured by the image sensor from a pair of image data input from the image sensors of both the left and right eyes, detects the amount of deviation in the position of the target pixels between the pair of images, and calculates the distance to the same object using the principle of triangulation. The output signal of camera 21 is input to ECU 11.

The vehicle C1 is further provided with a vehicle speed sensor 22, a steering angle sensor 23, and a yaw rate sensor 24. The vehicle speed sensor 22 outputs a detection signal in the form of a pulse signal synchronized with the rotation of a rotating body (e.g., a drive shaft) that rotates as the vehicle C1 travels. The steering angle sensor 23 outputs a detection signal corresponding to the steering angle (absolute steering angle) relative to the steering angle midpoint of the steering mechanism (e.g., a steering wheel) of the vehicle C1. The steering angle takes a positive value when the steering mechanism is turned to the right from the steering angle midpoint (the steering wheel is turned to the right), and takes a negative value when the steering mechanism is turned to the left (the steering wheel is turned to the left). The yaw rate sensor 24 outputs a detection signal corresponding to the yaw rate, which is the angular velocity of rotation around a vertical axis passing through the center of gravity of the vehicle C1. The detection signals of the vehicle speed sensor 22, the steering angle sensor 23, and the yaw rate sensor 24 are input to the ECU 11.

The vehicle C1 is equipped with a hydraulic brake system. The brake system includes a brake pedal, a brake booster, a master cylinder, a brake actuator 25, and brakes provided on each wheel. The brake pedal is located in a position that is convenient for the driver in the driver's seat to step on it with his right foot. When the brake pedal is stepped on, the force input to the brake pedal is transmitted to the brake booster. The brake booster uses the negative pressure generated in the engine's intake system, and the pressure difference between the negative pressure and atmospheric pressure amplifies the force applied to the brake pedal.

The force amplified by the brake booster is transmitted from the brake booster to the master cylinder, and hydraulic pressure corresponding to that force is generated from the master cylinder. The hydraulic pressure of the master cylinder is transmitted to the brake actuator 25, which supplies hydraulic pressure to the wheel cylinders of the brakes provided on each wheel, and the hydraulic pressure causes each brake to apply braking force to the wheel. The brake actuator 25 also has a built-in electric pump, which is driven by power from the battery when the automatic brake is activated, and the hydraulic pressure generated by the electric pump is supplied to each wheel cylinder.

The vehicle C1 is also provided with an alarm 26. The alarm 26 outputs various types of alarms, which may be output by light, sound, or voice.

Next, the ECU 11 will be described in detail with reference to FIG. 2. FIG. 2 is a diagram showing an example of the positional relationship between the host vehicle C1 and targets (vehicles C2, C3, and pedestrian M) in the first embodiment. In this example, the host vehicle C1 is traveling backward. However, the present invention is not limited to this, and can also be applied when the host vehicle C1 is traveling forward.

When the host vehicle C1 is traveling, the specified area (area R2) is defined by the length in the direction of travel (A: for example, "vehicle speed (m/s) x 3" (m)) corresponding to the vehicle speed of the host vehicle C1, and the length in the vehicle width direction (B: for example, "1 + distance (m) x 1.1" (m)) corresponding to the distance in the direction of travel from the host vehicle C1. The lateral length C of the rectangular area R is a predetermined value (for example, 9 (m)).

The ECU 11 (acquisition unit) acquires target information (such as position information) from the camera 21, which is information about targets present around the host vehicle C1.

The ECU 11 (determination unit) also determines whether or not a target exists in an outer region (region R1), which is an area outside a predetermined region (region R2) including the planned driving route of the vehicle C1, based on the target information. Note that in the example of FIG. 2, the targets are vehicles C2, C3, and pedestrian M, but vehicles C2 and C3 are stopped, and pedestrian M will be mainly used as an example of a target in the following description.

In addition, in the image captured by the camera 21, part of the body of the pedestrian M may be hidden by the vehicle C2, but if part of the body of the pedestrian M, such as the feet, is included in the captured image, it is possible not only to recognize the presence of the pedestrian M, but also to calculate the position of the pedestrian M and the distance from the vehicle C1 to the pedestrian M. In addition, recognition that the detected object is a human body can be achieved, for example, by image recognition technology such as pattern matching.

In addition, immediately after pedestrian M is walking and enters area R2 from area R1, ECU 11 (detection unit) detects pedestrian M in area R2 based on the target information.

Furthermore, when pedestrian M is detected in region R2, ECU 11 (calculation unit) calculates the collision risk based on the relative speed and distance (distance to pedestrian M; same below) of pedestrian M with respect to vehicle C1. In other words, since ECU 11 recognizes the position of pedestrian M from the time pedestrian M is present in region R1, it can calculate the relative speed of pedestrian M with respect to vehicle C1 immediately after detecting pedestrian M in region R2, and calculates the collision risk based on the relative speed and distance. For example, if the relative speed is the same, the shorter the distance, the higher the collision risk. Also, for example, if the distance is the same, the higher the relative speed, the higher the collision risk.

Figure 3 is a flowchart showing the processing by the driving assistance system 1 of the first embodiment. First, in step S1, the ECU 11 acquires target information around the host vehicle C1 from the camera 21. This acquisition of target information is performed, for example, at intervals of 50 ms.

Next, in step S2, the ECU 11 determines whether or not a target is present in the outer region (region R1) based on the target information, and if Yes, proceeds to step S3, and if No, returns to step S1. For example, if it is determined that a pedestrian M is present in region R1, the ECU 11 proceeds to step S3.

In step S3, the ECU 11 determines whether or not a target has been detected in a predetermined area (area R2). If the answer is Yes, the process proceeds to step S4. If the answer is No, the process returns to step S1. For example, if a pedestrian M has been detected in area R2, the process proceeds to step S4.

In step S4, the ECU 11 calculates the collision risk based on the relative speed and distance of the pedestrian M to the vehicle C1. The collision risk is calculated as one of three levels: "low collision risk," "medium collision risk," or "high collision risk," depending on factors such as the distance from the vehicle C1 to the pedestrian M.

Next, in step S5, the ECU 11 performs processing according to the collision risk calculated in step S4. For example, when the collision risk is "low," the ECU 11 executes a collision warning function to warn the driver of the possibility of a collision.

When the collision risk is "medium," the primary braking function is executed, and the vehicle C1 is decelerated at the primary target deceleration by automatic braking to prompt the driver to take action to avoid the collision.

In addition, when the collision risk is "high," the secondary brake function is executed, and the vehicle C1 is decelerated at the secondary target deceleration (> primary target deceleration) by automatic braking in order to avoid the collision and reduce the damage caused by the collision.

In this way, according to the first embodiment, the collision risk is calculated based on the relative speed of the target with respect to the vehicle C1 immediately after the target enters a specified area, thereby reducing the risk of collision between the vehicle C1 and the target. For example, a more effective pedestrian collision damage reduction system can be realized in a parking lot where there are many obstructions, such as parked vehicles, when the vehicle C1 is traveling.

Second Embodiment
Next, a second embodiment will be described. Descriptions of matters similar to those of the first embodiment will be omitted as appropriate. When a target is detected in a predetermined area, the ECU 11 (calculation unit) calculates a collision risk level based on a value obtained by adding a predetermined relative speed (e.g., about 1 m/s) to the relative speed of the target with respect to the host vehicle C1 and the distance.

Figure 4 is a flowchart showing the processing by the driving assistance system 1 of the second embodiment. Steps S1 to S3 are the same as steps S1 to S3 in Figure 3.

After step S3, in step S4a, the ECU 11 calculates the collision risk based on the distance and a value obtained by adding a predetermined relative speed to the relative speed of the pedestrian M with respect to the vehicle C1. Step S5 is the same as step S5 in FIG. 3.

With this configuration, the collision risk between the vehicle C1 and the target can be further reduced by calculating the collision risk based on the value obtained by adding a predetermined relative speed to the relative speed of the target with respect to the vehicle C1.

For example, if a pedestrian M who was not detected in region R1 (Fig. 2) is suddenly detected in region R2 (Fig. 2), even if the relative speed of pedestrian M cannot be calculated immediately after that, the collision risk can be calculated based on a value to which a predetermined relative speed (e.g., about 1 m/s) has been added. This can further increase the damage reduction effect.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

The program executed by the ECU 11 of this embodiment can be provided by recording it in an installable or executable file format on a recording medium that can be read by a computer device, such as a CD (Compact Disc)-ROM (Read Only Memory), a flexible disk (FD), a CD-R (Recordable), or a DVD (Digital Versatile Disk). The program can also be provided or distributed via a network such as the Internet.

In addition, the target objects are not limited to pedestrians and other vehicles, but include all moving objects such as bicycles, motorbikes, and animals (dogs, cats, etc.).

In addition, the sensor for detecting the target is not limited to a camera, but may be a sensor that uses electromagnetic waves, ultrasonic waves, etc.

In addition, in the second embodiment, the predetermined relative speed that is further added to the relative speed of the target is not limited to being a constant value, but may be, for example, a value that varies depending on the distance from the host vehicle C1 (for example, a larger value the smaller the distance from the host vehicle C1).

In addition, in an embodiment, if the specified relative speed cannot be calculated, the distance from the vehicle C1 to the pedestrian M may be subtracted (e.g., 1 m).

1... Driving assistance system, 11... ECU, 12... Microcomputer, 13... CPU, 14... Memory, 21... Camera, 22... Vehicle speed sensor, 23... Steering angle sensor, 24... Yaw rate sensor, 25... Brake actuator, 26... Alarm

Claims (4)

an acquisition unit that acquires target information, which is information on targets present around the host vehicle, from a predetermined sensor;
a determination unit that determines whether the target is present in an outer area that is an area outside a predetermined area including a planned driving route of the host vehicle based on the target information;
a detection unit that detects the target in the predetermined area based on the target information;
a calculation unit that calculates a collision risk level based on a relative speed of the target with respect to the host vehicle when the target is detected in the predetermined area by the detection unit ,
The calculation unit calculates the collision risk based on a value obtained by adding a predetermined relative speed to the relative speed of the target with respect to the host vehicle when the detection unit detects the target in the predetermined area . The driving assistance device according to claim 1 , wherein the predetermined area is defined according to a vehicle speed of the host vehicle while the host vehicle is traveling. 3. The driving assistance device according to claim 1, wherein, when the host vehicle is traveling, the predetermined area is defined by a length in a moving direction corresponding to a vehicle speed of the host vehicle and a length in a vehicle width direction of the host vehicle corresponding to a distance from the host vehicle in the moving direction . The driving support device according to claim 1 or 2, wherein the predetermined area is defined so as to widen in a vehicle width direction of the host vehicle as the predetermined area becomes farther away from the host vehicle.

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