Driving assistance method and driving assistance device

Abstract

The present invention provides a driving assistance method and a driving assistance device. The driving assistance device (1) comprises: a sensor (camera (10)) for detecting an object in front of a vehicle, and a controller (20). The controller (20) sets the detection range of the sensor (camera (10)) so that the detection range is expanded in the vehicle width direction when the vehicle is stopped compared to when the vehicle is following a preceding vehicle.

Description

Technical Field

[0001] The present invention relates to a driving assistance method and a driving assistance device. Background Art

[0002] Conventionally, an invention for automatically following a preceding vehicle is known (Patent Document 1). The invention described in Patent Document 1 detects the number of start requests when the vehicle stops and waits for a traffic light, and sets a start permission period based on the number of detected start requests.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2017 / 009940 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] When the vehicle starts from a stopped state following the vehicle in front, it is required to detect objects that may enter in front of the vehicle.

[0008] The present invention is proposed in view of the above-mentioned problems, and its object is to provide a driving assistance method and a driving assistance device that can detect objects that may enter in front of the vehicle.

[0009] Technical solutions to technical problems

[0010] A driving assistance method according to one embodiment of the present invention sets a detection range of a sensor for detecting an object in front of a host vehicle, and expands the detection range in the vehicle width direction when the host vehicle is stopped compared to when the host vehicle is following a preceding vehicle.

[0011] Effects of the Invention

[0012] According to the present invention, it is possible to detect an object that may enter in front of a host vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a configuration diagram of a driving assistance device 1 according to an embodiment of the present invention.

[0014] Figure 2 This is a diagram illustrating an example of a detection range.

[0015] Figure 3 This is a diagram illustrating another example of the detection range.

[0016] Figure 4 This is a diagram illustrating another example of the detection range.

[0017] Figure 5 This is a flowchart for explaining an operation example of the driving assistance device 1 .

[0018] Figure 6 This is a diagram illustrating an example of a method for setting a detection range.

[0019] Figure 7 This is a diagram illustrating another example of the detection range. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same parts, and the description thereof will be omitted.

[0021] Reference Figure 1 , an example configuration of a driving assistance device 1 is described. The driving assistance device 1 is installed in a vehicle equipped with an autonomous driving function. Autonomous driving functions include ACC (Adaptive Cruise Control), lane keeping, automatic lane changing, and automatic parking. However, in this embodiment, the driving assistance device 1 is primarily used for ACC. ACC is an autonomous driving function that automatically controls the acceleration and deceleration of the vehicle, using a speed set in advance by the user as an upper limit, to follow the vehicle ahead. Distance control is also performed to maintain the inter-vehicle distance corresponding to the set speed.

[0022] Following control also includes control to follow the preceding vehicle after detecting that the preceding vehicle has started moving, even when the own vehicle is stopped due to waiting for a traffic light or traffic congestion.

[0023] like Figure 1 As shown, the driving assistance device 1 includes a camera 10 , a radar 11 , a sonar 12 , a vehicle speed sensor 13 , a GPS receiver 14 , a switch 15 , a controller 20 , a steering actuator 30 , an accelerator pedal actuator 31 , and a brake actuator 32 .

[0024] Multiple cameras 10 are installed in the front, sides, rear, and side mirrors of the vehicle. Cameras 10 include imaging elements such as CCDs (charge-coupled devices) and CMOSs (complementary metal oxide semiconductors). Cameras 10 detect objects around the vehicle (pedestrians, bicycles, two-wheeled vehicles, other vehicles, etc.) as well as information about the vehicle's surroundings (dividing lines, traffic lights, signs, crosswalks, intersections, etc.). Cameras 10 output captured images to a controller 20.

[0025] Multiple radars 11 are installed in front of, to the sides of, and behind the vehicle. The radars 11 emit radio waves toward objects around the vehicle and measure the reflected waves, thereby determining the distance and direction to the objects. The radars 11 output the measured data to the controller 20.

[0026] The sonar 12 is mounted on the front bumper or grille. It emits ultrasonic waves and measures the reflected waves, thereby measuring the distance and direction of objects near the vehicle (e.g., approximately 1 to 2 meters). The sonar 12 outputs the measured data to the controller 20.

[0027] The vehicle speed sensor 13 detects the speed of the vehicle and outputs the detected speed to the controller 20 .

[0028] The GPS receiver 14 detects the position information of the vehicle on the ground by receiving radio waves from artificial satellites. The position information of the vehicle detected by the GPS receiver 14 includes latitude information and longitude information. It should be noted that the method of detecting the position information of the vehicle is not limited to the GPS receiver 14. For example, the position can also be estimated using a method called odometry. The odometry method is a method of estimating the position of the vehicle by calculating the movement amount and movement direction of the vehicle based on the rotation angle and rotation angular velocity of the vehicle. The location where the GPS receiver 14 is set is not particularly limited, but as an example, the GPS receiver 14 is set on the dashboard of the vehicle. The GPS receiver 14 outputs the detected position information to the controller 20.

[0029] The steering wheel is equipped with multiple switches 15. These switches 15 include a switch for selecting a radio channel, a switch for adjusting the volume, a switch for activating ACC, a switch for adjusting the speed controlled by ACC, a switch for setting the inter-vehicle distance when ACC is in effect, and a switch for initiating follow-up driving when the preceding vehicle starts. In this embodiment, the switches 15 are described as physical switches, but are not limited to this. The switches 15 may also be virtual switches. In this case, the switches 15 may be displayed on a touch panel used in the navigation system.

[0030] The controller 20 is an electronic control unit (ECU) having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and a CAN (Controller Area Network) communication circuit. A computer program for functioning as the driving assistance device 1 is installed in the controller 20. By executing the computer program, the controller 20 functions as a plurality of information processing circuits included in the driving assistance device 1. It should be noted that while an example of implementing the plurality of information processing circuits included in the driving assistance device 1 using software is shown here, it is also possible to prepare dedicated hardware for performing each of the information processing steps described below to constitute the information processing circuits. Alternatively, a single piece of hardware may constitute the plurality of information processing circuits. The controller 20 includes a lane detection unit 21, a preceding vehicle detection unit 22, a following driving unit 23, a stop determination unit 24, and a detection range setting unit 25 as the plurality of information processing circuits.

[0031] The lane detection unit 21 uses the image captured by the camera 10 to detect the lane in which the vehicle is traveling. Specifically, the lane detection unit 21 extracts the demarcation lines from the image to detect the lane in which the vehicle is traveling. The lane detection unit 21 can also add the vehicle's position information to detect the lane in which the vehicle is traveling.

[0032] The preceding vehicle detection unit 22 detects the preceding vehicle in front of the host vehicle using images acquired from the camera 10. Furthermore, the preceding vehicle detection unit 22 detects the distance between the host vehicle and the preceding vehicle, as well as the relative speeds of the preceding vehicle and the host vehicle, using data acquired from the radar 11. In this embodiment, the preceding vehicle is defined as a vehicle traveling in the same lane as the host vehicle.

[0033] The following driving unit 23 controls the vehicle so that it automatically follows the preceding vehicle. Specifically, when the user turns on the ACC switch, the following driving unit 23 controls the steering actuator 30, accelerator pedal actuator 31, and brake actuator 32 to cause the vehicle to follow the preceding vehicle, with the speed set by the user as the upper limit. At this time, the following driving unit 23 also performs distance control to maintain the inter-vehicle distance corresponding to the set speed. It should be noted that the user can also specify the inter-vehicle distance.

[0034] If the user turns on the ACC switch and no preceding vehicle is detected, the following driving unit 23 causes the host vehicle to travel at a set speed. If no speed is set, the following driving unit 23 can automatically drive the host vehicle using the legal speed limit on the road where the host vehicle is currently traveling as the upper limit.

[0035] The stop determination unit 24 determines whether the vehicle has stopped. Specifically, the stop determination unit 24 determines that the vehicle has stopped when the speed of the vehicle measured by the vehicle speed sensor 13 is 0 km / h.

[0036] The detection range setting unit 25 sets the detection range. In this embodiment, the detection range is defined as the range within which the camera 10 detects objects that could interfere with following control. Objects that could interfere with following control are vehicles that cut in while the host vehicle is traveling. Consider a scenario where the host vehicle is following a preceding vehicle and another vehicle cuts in between them. In this scenario, the following driving unit 23 decelerates the host vehicle and then follows the cutting vehicle. Alternatively, the following driving unit 23 may stop the host vehicle and release following control.

[0037] In addition, the object that may interfere with the following control is a pedestrian or a bicycle when the host vehicle is stopped. When the host vehicle is stopped, the pedestrian or the bicycle can be said to be an object that may enter the front of the host vehicle.

[0038] Next, refer to Figures 2 and 3 , the detection range set by the detection range setting unit 25 is described. Figure 2 The scene shown is a scene where the vehicle 40 follows the preceding vehicle 41 and drives automatically. In this scene, the detection range setting unit 25 sets the detection range R1. The detection range R1 is the area on the lane where the vehicle 40 is driving. The size of the detection range R1 is described below. Figure 2 As shown, the length of the detection range R1 in the vehicle width direction is the vehicle width W1 of the host vehicle 40. The length of the detection range R1 in the traveling direction is from the front end of the host vehicle 40 to the front end of the preceding vehicle 41.

[0039] The size of the detection range R1 is not limited to Figure 2 .like Figure 3 As shown in the detection range R2 of , the length in the vehicle width direction may be the width W2 of the lane in which the host vehicle 40 is traveling. In addition, the length in the traveling direction may be from the front end of the host vehicle 40 to the rear end of the preceding vehicle 41.

[0040] Figures 2 and 3 The detection ranges R1 to R2 described in the preceding paragraph are areas set when the host vehicle 40 follows the preceding vehicle 41 and automatically travels. Figure 4 , the detection range when the vehicle 40 is stopped is described. Figure 4The scenario shown is a scene where the preceding vehicle 41 and the host vehicle 40 are stopped while waiting for a traffic light. After the preceding vehicle 41 stops, the following driving unit 23 automatically stops the host vehicle 40 when it determines that the inter-vehicle distance is less than a predetermined value. At this time, the following driving unit 23 remains stopped.

[0041] When the host vehicle 40 is stopped, the detection range setting unit 25 expands the detection range in the vehicle width direction compared to when the host vehicle 40 is traveling. Figure 4 Indicated as R3. Figure 4 The detection range R3 shown is Figure 2 The detection range R1 shown or Figure 3 Compared to the detection range R2 shown in FIG. , the detection range R2 is wider in the vehicle width direction. Thus, when the host vehicle 40 is stopped, the controller 20 can detect objects (pedestrians 50) that may enter in front of the host vehicle 40 over a wider range than when the host vehicle 40 is moving. Furthermore, the controller 20 can detect objects that may enter in front of the host vehicle 40 more quickly when the host vehicle 40 is stopped than when the host vehicle 40 is moving.

[0042] When the host vehicle 40 is stopped and a pedestrian 50 is detected within the detection range R3, the controller 20 can restrict the behavior of the host vehicle 40. Details will be described later.

[0043] The size of detection range R3 will be explained. The length in the vehicle width direction is approximately twice the width of the host vehicle 40. This length is determined by taking into account the margin required to detect pedestrians 50 before the host vehicle 40 starts moving. Therefore, twice is an example and is not intended to be limiting. The length in the direction of travel is from the front end of the host vehicle 40 to the front end of the preceding vehicle 41. Although not specifically limited, specific values include 3 meters in the vehicle width direction and 10 meters in the direction of travel.

[0044] Then, in Figure 4 In the illustrated scenario, the behavior of the host vehicle 40 is described for the cases where a pedestrian 50 is detected within the detection range R3 and when no pedestrian 50 is detected. First, the case where no pedestrian 50 is detected within the detection range R3 is described. Assuming that the preceding vehicle 41 has already started, the host vehicle 40 will not automatically start. Unless the user inputs a start instruction (follow-up start instruction), the host vehicle 40 will not automatically start. The follow-up start instruction is input by operating a switch for activating follow-up travel or by operating the accelerator pedal. When the preceding vehicle 41 has already started, the follow-up travel unit 23 automatically starts the host vehicle 40 upon receiving the follow-up start instruction from the user.

[0045] Next, the case where a pedestrian 50 is detected within detection range R3 will be described. In this case, assuming that the user has input a follow-up start instruction, the following travel unit 23 prohibits the follow-up start while the pedestrian 50 is detected. If the pedestrian 50 is no longer detected within detection range R3, the following travel unit 23 automatically starts the host vehicle 40.

[0046] Alternatively, the follow-up driving unit 23 can disable the follow-up start system if a pedestrian 50 is detected within detection range R3. In this case, if the user inputs a follow-up start instruction and no pedestrian 50 is detected within detection range R3, the vehicle 40 will not automatically start. This prevents follow-up starting in an area where a pedestrian 50 might pass in front of the vehicle 40 if the pedestrian 50 is detected after the vehicle 40 stops. Furthermore, since the user cannot use the follow-up start system, they must manually start the vehicle 40. This allows the user to start the vehicle 40 after confirming the road ahead. It should be noted that even if the follow-up start system is disabled, the vehicle 40 can still remain stopped.

[0047] Next, refer to Figure 5 An operation example of the driving assistance device 1 will be described with reference to the flowchart of FIG.

[0048] In step S101, the stop determination unit 24 determines whether the host vehicle 40 has stopped using the speed of the host vehicle 40 measured by the vehicle speed sensor 13. If the speed of the host vehicle 40 is 0 km / h (YES in step S101), the process proceeds to step S103. If the speed of the host vehicle 40 is not 0 km / h (NO in step S101), the series of processes ends.

[0049] In step S103, the detection range setting unit 25 expands the detection range in the vehicle width direction compared to when the host vehicle 40 is traveling (see Figure 4 ).

[0050] The process proceeds to step S105. If a pedestrian 50 is detected within the expanded detection range R3 (YES in step S105), the following travel unit 23 prohibits the follow-up start. In other words, the following travel unit 23 disables the follow-up start system. On the other hand, if no pedestrian 50 is detected within the expanded detection range R3 (NO in step S105), the following travel unit 23 automatically starts the host vehicle 40 to follow the preceding vehicle 41 in accordance with the follow-up start instruction from the user.

[0051] (Effect)

[0052] As described above, according to the driving assistance device 1 of the present embodiment, the following operational effects can be obtained.

[0053] The detection range setting unit 25 sets the detection range of the sensor for detecting an object in front of the host vehicle 40. The detection range setting unit 25 expands the detection range in the vehicle width direction when the host vehicle 40 stops compared to when the host vehicle 40 is traveling following the preceding vehicle 41 (see Figure 4 ). Thus, when the host vehicle 40 is stopped, the controller 20 can detect objects (pedestrians 50) that may enter in front of the host vehicle 40 over a wider range than when the host vehicle 40 is moving. In addition, when the host vehicle 40 is stopped, the controller 20 can detect objects that may enter in front of the host vehicle more quickly than when the host vehicle 40 is moving.

[0054] Furthermore, the detection range of the host vehicle 40 is smaller when it is moving than when it is stopped. Therefore, when the host vehicle 40 is moving, the controller 20 can prevent control based on objects other than those that could interfere with the following control (such as adjacent vehicles, trees, and pedestrians walking on a crosswalk). It should be noted that adjacent vehicles are vehicles traveling in lanes adjacent to the lane in which the host vehicle 40 is traveling.

[0055] If the following driving unit 23 detects an object within the expanded detection range in the vehicle width direction, it prohibits the host vehicle 40 from starting to follow the preceding vehicle 41. This prevents the host vehicle 40 from starting to follow the preceding vehicle 41, even if the host vehicle 40 detects a pedestrian 50 after stopping. Furthermore, since the user cannot utilize the following start system, the user must manually start the host vehicle 40. This allows the user to start the host vehicle 40 while confirming the direction ahead.

[0056] It should be noted that the controller 20 can also determine whether the vehicle 40 is traveling on a motor vehicle lane based on the location information of the vehicle 40. A motor vehicle lane in Japan is defined as a road designated by a road manager on which only motor vehicles are allowed to travel. A typical motor vehicle lane is a highway. When it is determined that the vehicle 40 is traveling on a motor vehicle lane and an object is detected within the detection range expanded in the vehicle width direction, the controller 20 can also prohibit the vehicle 40 from following the preceding vehicle 41 and starting. The detection of pedestrians 50 or bicycles on a motor vehicle lane where there are no pedestrians 50 or bicycles may be due to erroneous location information being identified due to reduced accuracy of the GPS receiver 14. In the above case, the reliability of the system is improved by prohibiting the following start by the controller 20.

[0057] While the detection range setting unit 25 has been described as expanding the detection range using the stop of the host vehicle 40 as a trigger, this is not necessarily limited to expanding the detection range at the moment the host vehicle 40 stops. Specifically, after the host vehicle 40 stops, the detection range setting unit 25 may not change the detection range until a predetermined time has elapsed, but may expand the detection range after the predetermined time has elapsed. This is achieved by setting two modes (a first mode and a second mode) as modes that allow follow-up starting.

[0058] The first and second modes are described below. The first mode allows following vehicle start after the host vehicle 40 stops until a first predetermined time has passed and the preceding vehicle 41 has started. The second mode allows following vehicle start after a second predetermined time has passed, which is longer than the first predetermined time. An example of the first predetermined time is 3 seconds, and an example of the second predetermined time is 30 seconds. The first and second modes are set by the controller 20. The detection range setting unit 25 may maintain the detection range in the first mode but expand the detection range in the second mode.

[0059] Reference Figure 6 , and explain it with reference to a specific example. Figure 6 The first scene shown is a scene from when the host vehicle 40 stops to when the first prescribed time (3 seconds) has passed. That is, in the first scene, the mode of the host vehicle 40 is the first mode. Figure 6 As shown, the detection range setting unit 25 does not change the detection range R1 in the first mode. Figure 6 The second scene shown is a scene from the first predetermined time (3 seconds) to the second predetermined time (30 seconds). That is, in the second scene, the mode of the vehicle 40 is the second mode. Figure 6 As shown, the detection range setting unit 25 expands the detection range R1 in the vehicle width direction in the second mode (the expanded detection range is indicated as R3).

[0060] In the second mode, the start permission time is longer than in the first mode. When the start permission time is extended, the stop time is also extended. Therefore, by expanding the detection range in the vehicle width direction in the second mode, object detection is made easier. It should be noted that if the leading vehicle 41 does not start even after the second predetermined time has passed, the following travel unit 23 deactivates the following start system.

[0061] In this embodiment, the detection range set by the detection range setting unit 25 is the detection range of the camera 10. The object detected by the camera 10 is at least one of a pedestrian 50 and a bicycle. By limiting the device for detecting pedestrians 50 or bicycles within the detection range R3, which expands in the vehicle width direction, to the camera 10, other vehicles in adjacent lanes near the lane in which the host vehicle 40 is traveling can be excluded from detection targets.

[0062] The controller 20 can also detect pedestrians 50 or bicycles based on changes in the rear end of the preceding vehicle 41 displayed in the camera image. When a pedestrian 50 or bicycle passes in front of the host vehicle 40, the image of the rear end changes. If the image of the rear end changes, the controller 20 can determine the presence of a pedestrian 50 or bicycle. This allows the controller 20 to detect pedestrians 50 or bicycles with shapes that are difficult to identify as objects.

[0063] Each function described in the above embodiments can be implemented by one or more processing circuits. A processing circuit includes a programmable processing device such as a processing device with an electronic circuit. A processing circuit also includes a device such as an application-specific integrated circuit (ASIC) or circuit accessories arranged to perform the functions.

[0064] The embodiments of the present invention are described above, but the description and drawings constituting part of this disclosure should not be construed as limiting the present invention. Based on this disclosure, various alternative embodiments, examples, and application techniques will be apparent to those skilled in the art.

[0065] In the above embodiment, the camera 10 is used as the sensor for detecting objects within the detection range set by the detection range setting unit 25. However, a sonar 12 may be added in addition to the camera 10. While the camera 10 detects pedestrians 50 or bicycles, the sonar 12 is not particularly limited in its detection targets. The object detection method performed by the sonar 12 will be described. When the distance information within the lane where the vehicle 40 is stopped changes by a predetermined value or more, the object is detected. Alternatively, the object may be detected when the distance information changes dramatically. It should be noted that the sonar 12 is only used when the vehicle 40 is stopped.

[0066] like Figure 7 As shown, when traffic congestion occurs on the highway, the detection range set by the detection range setting unit 25 is the detection range R1. The size of the detection range R1 is as described above, so the description thereof is omitted.

[0067] Description of Reference Numerals

[0068] 1 Driving assistance device; 10 Camera; 11 Radar; 12 Sonar; 13 Vehicle speed sensor; 14 GPS receiver; 15 Switch; 20 Controller; 21 Lane detection unit; 22 Front vehicle detection unit; 23 Following driving unit; 24 Stop determination unit; 25 Detection range setting unit; 30 Steering actuator; 31 Accelerator pedal actuator; 32 Brake actuator.

Claims

1. A driving assistance method comprising a controller for controlling a vehicle to automatically drive following a preceding vehicle in front of the vehicle, wherein: The controller sets a detection range of a sensor for detecting an object in front of the host vehicle, When the host vehicle stops, the controller expands the detection range in the vehicle width direction compared to when the host vehicle follows the preceding vehicle. Furthermore, when the object other than the vehicle is detected within the detection range expanded in the vehicle width direction, the controller cancels the system in which the host vehicle starts following the preceding vehicle.

2. The driving assistance method according to claim 1, wherein: The controller obtains the position information of the vehicle. The controller determines whether the vehicle is traveling on a motor vehicle lane based on the position information. The controller prohibits the host vehicle from starting to follow the preceding vehicle when it is determined that the host vehicle is traveling on the motor vehicle-only lane and the object other than the vehicle is detected within the detection range expanded in the vehicle width direction.

3. The driving assistance method according to claim 1 or 2, wherein: The controller sets: a first mode that allows the host vehicle to start following the preceding vehicle if the preceding vehicle has started before a first predetermined time has passed since the host vehicle stopped; a second mode in which, if the preceding vehicle has started before a second predetermined time, which is longer than the first predetermined time, has elapsed, the preceding vehicle is allowed to start following the preceding vehicle; In the second mode, the detection range is expanded in the vehicle width direction.

4. The driving assistance method according to claim 1 or 2, wherein: The sensor is a camera, The object detected by the camera is at least either a pedestrian or a bicycle.

5. The driving assistance method according to claim 4, wherein: Using the camera, the rear end of the preceding vehicle is photographed. The controller detects the pedestrian or the bicycle based on a change in the rear end portion shown in an image captured by the camera.

6. A driving assistance device for controlling a vehicle to automatically drive following a preceding vehicle in front of the vehicle, the driving assistance device comprising: a sensor for detecting an object in front of the host vehicle; Controller; The controller sets the detection range of the sensor, When the host vehicle stops, the controller expands the detection range in the vehicle width direction compared to when the host vehicle follows the preceding vehicle. Furthermore, when the object other than the vehicle is detected within the detection range expanded in the vehicle width direction, the controller cancels the system in which the host vehicle starts following the preceding vehicle.

7. A driving assistance method comprising: a controller for controlling a host vehicle so as to automatically drive following a preceding vehicle in front of the host vehicle; the driving assistance method comprising: The controller sets a detection range of a sensor for detecting an object in front of the vehicle. When the host vehicle stops, the controller expands the detection range in the vehicle width direction compared to when the host vehicle follows the preceding vehicle. Furthermore, when a pedestrian is detected within the detection range expanded in the vehicle width direction, the controller cancels the system in which the host vehicle starts following the preceding vehicle.

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