Driving assistance method and driving assistance device

Abstract

Provided is a driving assistance method for use by a processor (10). In said method, when executing driving assistance that issues a warning sound if a host vehicle and a prescribed object approach each other, the processor (10) predicts driving details of the host vehicle on the basis of operation information input by the driver of the host vehicle, and, after the input of the operation information and before execution of the driving in the predicted driving details has started, outputs, by text, the reason for issuing the warning sound on the basis of the predicted driving details.

Description

Driving assistance method and driving assistance device

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

[0002] There is a system that warns the driver when it is determined that the vehicle is in a dangerous state, and notifies the driver of the content of the warning after the dangerous state has been resolved.

[0003] JP 2008-123112 A

[0004] However, with the conventional technology, the driver may be surprised by the warning sound.

[0005] The problem to be solved by the present invention is to prevent the driver from being startled by the warning sound.

[0006] The present invention solves the above problem by predicting the driving content of the vehicle based on input operation information when performing driving assistance that issues a warning sound when the vehicle approaches a specified object, and by notifying the driver in text form of the reason for issuing the warning sound based on the predicted driving content after the input of the operation information and before the driver begins to drive the predicted driving content.

[0007] According to the present invention, it is possible to prevent the driver from being surprised by the warning sound.

[0008] Fig. 1 is a block diagram showing an example of a hardware configuration of a driving assistance device; Fig. 2 is a flowchart showing an example of a driving assistance processing procedure; Fig. 3 is a diagram showing an example of correspondence information used in the driving assistance processing; Fig. 4 is a flowchart showing a driving assistance processing procedure subroutine; Fig. 5 is a flowchart showing a driving assistance processing procedure subroutine;

[0009] FIG. 1 shows the hardware configuration of a driving assistance system 100 including a driving assistance device 1. The driving assistance system 100 includes the driving assistance device 1, a plurality of sensors 2 (sensor group) that cooperate with the driving assistance device 1, a driving information acquisition device 3, a navigation device 4, and a vehicle controller 200. The driving assistance device 1 of this embodiment includes a processor 10 that executes control processing for driving assistance, an output device 20, an input device 30, and a communication device 40. The driving assistance method of this embodiment is implemented using the processor 10. The processor 10 of the driving assistance device 1 and these devices are connected via a communication device 40 such as a Controller Area Network (CAN) or other in-vehicle LAN, and exchange information with each other. The driving assistance device 1 cooperates with one or more of the plurality of sensors 2, the driving information acquisition device 3, and the navigation device 4.

[0010] The sensors 2 acquire detection information according to their respective functions. The sensors 2 transmit the acquired detection information to the processor 10 of the driving assistance device 1. The sensors 2 acquire information for calculating the distance to an object, the arrival time, and changes therein. In this embodiment, the term "object" includes three-dimensional objects such as other vehicles (including two-wheeled vehicles, four-wheeled vehicles, and trucks), pedestrians, animals, signs, billboards, and obstacles, as well as two-dimensional objects such as the lane in which the vehicle is traveling and lane markings for one or more lanes parallel to it, and signs displayed on the road surface. The sensors 2 provide the acquired detection information to the processor 10.

[0011] The sensor 2 includes a camera 21 or a radar device 22. The single or multiple cameras 21 capture images of the vehicle's surroundings in all directions. The camera 21 may include an image sensor with an imaging element such as a CCD, an ultrasonic camera, or an infrared camera. The camera 21 includes at least a front camera that captures images in front of the vehicle, a rear camera that captures images of the rear or rear side of the vehicle, a right camera that captures images of the right side, front right, and rear right of the vehicle, and a left camera that captures images of the left side, front left, and rear left of the vehicle. The type of camera 21 is not limited as long as it can capture images of the vehicle in all directions. A single camera 21 mounted on a base with a rotation mechanism may be used. The camera 21 captures images of objects in all directions (front, rear, left, and right sides) of the vehicle. The captured images of the "objects" captured by the camera 21 are provided to the processor 10. The radar device 22 detects the presence of objects around the vehicle, their positions and changes in their positions, the size (width and height) of the objects, and the area occupied by the objects. The sensor 2 includes a radar device 22 that includes a laser radar, a millimeter-wave radar, a LiDAR (light detection and ranging) unit, and an ultrasonic radar. The existence, distance, and position of an "object" measured by the radar device 22 are provided to the processor 10. The driving assistance device 1 cooperates with an external device, such as a server outside the vehicle or a roadside device, via a communication device 40, such as a wireless communication device, to acquire images captured by a camera of the roadside device functioning as the sensor 2, and the position and distance of the object measured by a distance measuring device of the roadside device. The processor 10 calculates the proximity between the object and the vehicle based on the detection information acquired from the sensor 2.

[0012] The driving information acquisition device 3 acquires driving information including operation information input to the vehicle. The operation information is input by the driver of the vehicle. The operation information includes shift position information (drive position, parking position, rear position), steering information (including steering amount, steering speed, and steering acceleration), driving information (including braking amount and acceleration amount), speed information (including acceleration and jerk), traveling direction information, attitude information, and behavior information. The driving information acquisition device 3 acquires operation information input via an input device 30 that functions as an operating device such as a steering wheel, brake pedal, accelerator pedal, shift lever, or turn signal of the vehicle. The input device 30 may provide the acquired operation information directly to the processor 10 or may provide it to the processor 10 via the driving information acquisition device 3. The driving information acquisition device 3 acquires necessary information from one or more of the vehicle's steering sensor, vehicle speed sensor, acceleration sensor, braking sensor, traveling direction sensor, attitude sensor, shift position sensor, and behavior sensor. The driving information acquisition device 3 may acquire this information via the vehicle controller 200. The driving information acquisition device 3 acquires the current position as driving information from a position detection device 41 of the navigation device 4, which will be described later. The driving information acquisition device 3 can also acquire each of the above information from the vehicle controller 200. The driving information acquisition device 3 provides the acquired driving information to the processor 10.

[0013] The navigation device 4 includes a position detection device 41 and map information 42. The navigation device 4 refers to the map information 42 and calculates a route to a set destination. This route includes a target trajectory in which the lanes to travel are identified. The route and target trajectory calculated by the navigation device 4 are provided to the vehicle controller 200 and used for autonomous driving control. The position detection device 41 includes a GPS (Global Positioning System) unit and a gyro sensor, and detects the position of the vehicle. The map information 42 stores lane identification information, the number of lanes, the positions of lane boundaries (the positions of lane marks, guardrails, and boundary structures), and the positions of adjacent lanes.

[0014] The driving assistance system 100 includes a vehicle controller 200. The vehicle controller 200 executes driving assistance control. The driving assistance control provides assistance to autonomous driving control or manual driving control by the driver. The vehicle controller 200 includes a steering control device 210 and a drive control device 220. The vehicle controller 200 acquires command values ​​for autonomous driving control according to a driving plan formulated by the processor 10 of the driving assistance device 1, and controls the host vehicle along a route to a destination. The command values ​​for autonomous driving control are vehicle control command values ​​for the host vehicle to travel at a predetermined speed along a target trajectory. Based on the command values, the vehicle controller 200 inputs longitudinal and lateral forces that control the traveling position of the host vehicle to the steering control device 210 and / or the drive control device 220, and controls the behavior of the vehicle body and the behavior of the wheels so that the host vehicle travels autonomously along a route according to these inputs. Based on these controls, at least one of the drive actuators and braking actuators of the drive mechanism of the vehicle body controlled by the drive control device 220 and the steering actuator of the steering control device 210, which is activated as needed, operate autonomously, and autonomous driving control is executed to make the vehicle travel autonomously along a target trajectory. The vehicle controller 200 performs driving in accordance with command values ​​based on manual operation by the driver input via the input device 30. The processor 10 provides assistance in autonomous driving and / or manual driving of the host vehicle to avoid contact with obstacles, lane departure, approaching a vehicle behind, and approaching a pedestrian or oncoming vehicle.

[0015] The processor 10 of the driving assistance device 1 executes a driving assistance method for assisting the driving of the vehicle. The processor 10 includes a ROM (Read Only Memory) 12 that stores programs for implementing a function of executing control to assist the driving of the vehicle and a function of outputting information as one form of driving assistance using an output device 20, a CPU (Central Processing Unit) 11 that executes the programs stored in the ROM 12, and a RAM (Random Access Memory) 13 that functions as an accessible storage device. The processor 10 executes the above functions through at least software that commands output control of information for driving assistance and in cooperation with the hardware components shown in FIG. 1 .

[0016] The output device 20 outputs audio information or display information generated by the processor 10. The output device 20 includes a speaker 201 and a display 202. The speaker 201 issues a text read-out voice or a warning sound such as a siren or beep. The display 202 presents text or image information. The output device 20 may include a lamp that lights up to notify information. As described above, the input device 30 acquires operation information from an occupant and provides it to the processor 10. The occupant in this embodiment includes the driver. The input device 30 may be configured as a touch panel display 202, or may be configured as a switch, button, etc. The communication device 40 has wireless communication capabilities including short-range communication, and transmits and receives information by connecting to the vehicle's CAN or other in-vehicle LAN, or to a communication network external to the vehicle.

[0017] The processor 10 of the driving assistance device 1 executes driving assistance for the vehicle. In this embodiment, the driving assistance includes one or more of: (A) obstacle avoidance, (B) lane departure prevention, (C) rear vehicle detection, (D) front emergency braking with pedestrian detection (hereinafter referred to as "front emergency braking" or "FEB"), and (E) front emergency braking with oncoming vehicle detection (hereinafter referred to as "FEB" or "FEB"). These driving assistance functions are executed during autonomous driving or manual driving. When executing each of the above driving assistance functions, the processor 10 issues an alarm if the vehicle approaches a predetermined object. Issuing this alarm is one of the driving assistance functions. The processor 10 issues an alarm if a predetermined condition predefined for each driving assistance function is met based on the proximity between the vehicle and the object. For example, the processor 10 calculates the proximity between the vehicle and the predetermined object, and issues an alarm if the proximity falls below a predetermined value. The "conditions" for issuing a warning sound are defined for each type (function) of driving assistance. Specifically, the monitored target, the definition of proximity, and the proximity threshold are defined for each driving assistance. The proximity can be defined using index values ​​such as TTC (Time To Collision) or THW (Time-Headway), or their derivatives or inverses. Examples of conditions for issuing a warning sound for each driving assistance are described below. (A) In obstacle avoidance, the specified target is an obstacle present around the host vehicle. In obstacle avoidance, the processor 10 issues a first warning sound when an obstacle (object) is present in front of or behind the host vehicle within a range less than a specified first proximity from the host vehicle. The proximity threshold (first proximity) when an obstacle is present in front of the host vehicle and the proximity threshold (first proximity) when an obstacle is present behind the host vehicle may be set to the same value or different values. The warning sound when an obstacle is present in front of the host vehicle and the warning sound when an obstacle is present behind the host vehicle may be the same sound or different sounds. (B) In lane departure prevention, the predetermined target is a lane mark of the lane the host vehicle is traveling in. In lane departure prevention, processor 10 issues a second warning sound when the lane mark (target) of the traveling lane is within a range of less than a predetermined second proximity to the reference lateral position of the host vehicle.(C) In rear vehicle detection, the predetermined target is a rear vehicle traveling behind the host vehicle in a lane adjacent to the host vehicle's lane. In rear vehicle detection, the processor 10 issues a third warning sound when the rear vehicle (target) is within a predetermined third proximity from the host vehicle. (D) In ​​FEB with pedestrian detection, the predetermined target is a pedestrian located at an intersection into which the host vehicle may enter. In FEB with pedestrian detection, the processor 10 issues a fourth warning sound when the pedestrian (target) is within a predetermined fourth proximity from the host vehicle. (E) In FEB with oncoming vehicle detection, the predetermined target is an oncoming vehicle approaching an intersection into which the host vehicle may enter. In oncoming vehicle detection, the processor 10 issues a fifth warning sound when the oncoming vehicle (target) is within a predetermined fifth proximity from the host vehicle. The first to fifth proximity degrees are set according to the general relative speed between the target and the host vehicle. These may be the same value as each other, or may be different values. The first to fifth warning sounds may be the same sound as each other, or may be different sounds.

[0018] The execution process of the driving assistance of this embodiment will be described based on the flowchart in FIG. 2. The flow of the main routine is indicated by solid lines, and the flow of the subroutine is indicated by dashed lines. The processor 10 of the driving assistance device 1 executes driving assistance ((A) to (D) described above) that assists driving of the vehicle, driving assistance that issues a warning sound when the vehicle approaches an object while driving, and driving assistance that outputs the reason for issuing the warning sound before issuing the warning sound. The processor 10 waits for input of driver operation information (S1) and acquires the operation information input by the driver (S2). The operation information is input by the driver while driving the vehicle via operating devices such as a shift lever, brake pedal, accelerator pedal, steering wheel, or blinker. The operation information is acquired via the input device 30, the driving information acquisition device 3, or the vehicle controller 200.

[0019] The processor 10 predicts the driving behavior based on the operation information (S3). The driving behavior includes forward driving, reverse driving, overtaking driving, lane change driving, and right / left turn driving. The processor 10 predicts the driving behavior (forward or reverse) based on the operation information including the position of the shift lever. The processor 10 predicts that the driving behavior of the host vehicle is reverse based on the operation information that the shift lever is in the reverse position. The processor 10 determines that the driving behavior of the host vehicle is forward based on the operation information that the shift lever is in the drive position. Incidentally, if a reverse driving behavior is performed by the host vehicle and the host vehicle approaches an obstacle behind while reversing, an alarm is sounded. Similarly, if a forward driving behavior is performed by the host vehicle and the host vehicle approaches an obstacle ahead while driving forward, an alarm is sounded. By predicting the driving behavior of the host vehicle based only on the operation information, the processing speed of the driving behavior prediction can be increased, and as a result, the reason for sounding the alarm can be output to the occupant in a timely manner.

[0020] Although not particularly limited, in this embodiment, the processor 10 may detect the surroundings of the vehicle using the sensor 2 (S21) and acquire detection information about the surroundings of the vehicle (S22) in parallel with the processing of S1-S2. The processing of S21-S22 can be skipped. When the detection processing of S21-S22 is executed, the processor 10 predicts the driving behavior based on the detection information about the surroundings of the vehicle and the operation information (S3). For example, the processor 10 predicts that the driving behavior is overtaking driving based on detection information that an obstacle is detected ahead of the vehicle and operation information that does not include a turn signal operation input of the vehicle's turn signal. The processor 10 acquires detection information from the sensor 2 that an obstacle such as a parked vehicle is present ahead of the vehicle, and when it determines that operation information acquired within a predetermined time after detecting the obstacle ahead does not include a turn signal operation input, it predicts that the driving behavior of the vehicle is overtaking driving to overtake the obstacle ahead in the driving lane. The processor 10 predicts that the driving behavior of the host vehicle is a lane-changing behavior based on detection information indicating that a vehicle ahead of the host vehicle is detected at a relative speed less than a predetermined value and operation information that does not include a brake operation input. For example, if the processor 10 acquires detection information from the sensor 2 indicating that the vehicle ahead is moving at a speed less than a predetermined value and determines that operation information acquired within a predetermined time after the detection of the vehicle ahead does not include a brake operation input signal, the processor 10 predicts that the driving behavior of the host vehicle is a lane-changing behavior to overtake the vehicle ahead. The processor 10 predicts that the driving behavior of the host vehicle is a right-left turn behavior based on detection information indicating the presence of an intersection in the host vehicle's direction of travel and operation information including the operation of the host vehicle's turn signal. In addition, the processor 10 may determine that the driving behavior is a right-left turn behavior when the host vehicle is in a right-left turn-only lane. Whether the host vehicle is traveling in a right-left turn-only lane can be determined based on the host vehicle's position obtained from the position detection device 41, with reference to high-precision map information 42 that identifies lanes. The processor 10 acquires detection information from the sensor 2 or the navigation device 4 that an intersection is located in the direction of travel of the vehicle, and if a blinker operation is input within a predetermined time after the intersection is detected, predicts that the vehicle will be turning right or left. By predicting the vehicle's driving behavior based on the operation information and detection information, the accuracy of the prediction of the driving behavior can be improved, and as a result, the appropriate reason for issuing a warning sound can be output.

[0021] The processor 10 acquires a reason for issuing an alarm based on the driving content (S4), and generates audio text information for output or visually recognizable text information via a display (S5). The processor 10 references correspondence information ( FIG. 3 ) that previously associates driving content with reasons for issuing an alarm, acquires the reason to be output based on the predicted driving content, and generates the text information. The correspondence information shown in FIG. 3 associates driving content with reasons / conditions for issuing an alarm. The correspondence information in the same figure associates driving content with text information corresponding to reasons / conditions for issuing an alarm. The processor 10 references the correspondence information in FIG. 3 to generate text information corresponding to the reason for issuing an alarm based on the driving content. For example, when the driving content is backing up / forward, the processor 10 references the correspondence information in FIG. 3 and outputs the text corresponding to the reason, such as "Approaching an obstacle behind / forward" or "An alarm will be sounded when approaching an obstacle behind / forward."

[0022] Although not particularly limited, the processor 10 may identify the driving assistance to be performed based on the predicted driving content, and output the reason for issuing a warning sound for the identified driving assistance in text format. After predicting the driving content (S3), the processor 10 identifies the driving assistance to be performed based on the predicted driving content (S7). S7 can be skipped. The driving content and the driving assistance to be activated when the driving content is performed are pre-associated and stored as correspondence information. The processor 10 identifies the driving assistance corresponding to the driving content by referring to the correspondence information between the driving content and the driving assistance prepared in advance. Figure 3 shows the correspondence information that associates "driving assistance" and "driving content," including the above-mentioned (A) obstacle avoidance, (B) lane departure prevention, (C) rear vehicle detection, (D) FEB with pedestrian detection, and (E) FEB with oncoming vehicle detection. In the correspondence information, the driving assistance that will assist the driving of the host vehicle when the driving content is performed is associated with each driving content. Therefore, if the driving content can be predicted, the driving assistance to be performed can be identified. In this embodiment, if the predicted driving content is reverse / forward, the driving assistance to be activated is identified as obstacle avoidance; if the predicted driving content is overtaking an obstacle, the driving assistance to be activated is identified as lane departure prevention; if the predicted driving content is a lane change, the driving assistance to be activated is identified as rear vehicle detection; and if the predicted driving content is a right or left turn, the driving assistance to be activated is identified as FEB detection with pedestrian detection or FEB with oncoming vehicle detection. For example, if the processor 10 predicts the driving content as overtaking and identifies the driving assistance as lane departure prevention, it references the correspondence information in Figure 3 and outputs text such as "approaching a lane mark" or "a warning sound will be sounded if there is a risk of approaching or leaving the lane," which are reasons associated with lane departure prevention.

[0023] In the process of identifying driving assistance, processor 10 can additionally use the driving scene of the host vehicle determined based on the detection information. Processor 10 acquires the detection information (S22), determines the driving scene of the host vehicle based on the detection information (S23), and identifies driving assistance based on the driving content predicted from the operation information and / or detection information and the driving scene. Processes S21-S22 or S21-S23 can be skipped. Processor 10 determines the driving scene of the host vehicle to be a large space such as a parking lot based on the detection information of sensor 2. If the driving content of the host vehicle is forward and / or backward and the driving scene is a parking lot, the driving assistance that assists the driving of the host vehicle is obstacle avoidance during parking. Processor 10 determines the driving scene of the host vehicle to be lane markings on the driving lane based on the detection information of sensor 2. If the driving content of the host vehicle is overtaking an obstacle ahead and the driving scene is a lane with lane markings, the driving assistance that assists the driving of the host vehicle is lane departure prevention. Based on the detection information from sensor 2, processor 10 determines the driving situation of the host vehicle, namely, that the road on which the host vehicle is traveling has two or more lanes. If the driving situation of the host vehicle is overtaking a slow-moving vehicle ahead and the driving situation is a road with two or more lanes, the driving assistance that assists the driving of the host vehicle is determined to be rear vehicle detection during lane change. Based on the detection information from sensor 2, processor 10 determines the driving situation of the host vehicle, namely, that the host vehicle is entering an intersection where there is a possibility of approaching a pedestrian and / or an oncoming vehicle. Details of this determination will be described later. If the driving situation of the host vehicle is turning right or left at an intersection and the driving situation is entering an intersection where there is a possibility of approaching a pedestrian and / or an oncoming vehicle, the driving assistance that assists the driving of the host vehicle is determined to be FEB with pedestrian detection or FEB with oncoming vehicle detection. Processor 10 determines the driving situation of the host vehicle based on the detection information and determines the driving assistance based on the predicted driving situation and the driving situation. As described above, driving assistance is performed in a specific driving situation. For example, the lane departure prevention function cannot be performed on lanes without lane markings, and the function of detecting vehicles behind the vehicle when changing lanes cannot be performed if there are no adjacent lanes.The processor 10 determines a driving scene in which driving assistance may be activated, and specifies the driving assistance based on the driving content predicted for that driving scene. By specifying the driving assistance using the driving scene determined based on the detection information in addition to the driving content, it is possible to accurately specify the driving assistance to be activated in the vehicle while it is moving, and to accurately output the reason for issuing a warning sound.

[0024] The processor 10 acquires the reason for issuing a warning sound in the specified driving assistance (S4), and generates audio text information or visible text information for output (S5). The processor 10 references correspondence information that previously associates driving assistance with the reason for issuing a warning sound, acquires the reason to be output in the specified driving assistance based on the predicted driving content, and generates the text information. The correspondence information shown in Figure 3 associates driving assistance with the reason / condition for issuing a warning sound. The correspondence information in the same figure associates driving assistance with text information corresponding to the reason / condition for issuing a warning sound in the driving assistance. The processor 10 references the correspondence information in Figure 3 and generates text information corresponding to the reason for issuing a warning sound based on the driving assistance.

[0025] The processor 10 outputs the reason for issuing a warning sound for the driving assistance identified based on the driving content by displaying the reason in text (S6). The reason for issuing a warning sound is output as audio text information via the speaker (201) or as visible text information via the display (202). The reason for issuing a warning sound is the cause of issuing the warning sound. The reason is created by the processor 10 based on the detection information. The information constituting the reason may originate from the detection information or may be a judgment result regarding the driving content or driving scene determined based on the detection information. For example, detection information indicating "the presence of an obstacle ahead" detected by the sensor 2 at the time when the driving content prediction or specific processing for the driving assistance is performed may be output as the reason for issuing a warning sound. In this specification, "reason for issuing a warning sound" includes "conditions for issuing a warning sound." The reason for issuing a warning sound may be a predetermined condition defined in advance to issue a predefined warning sound for each driving assistance. An alarm is actually sounded when a predetermined condition predefined for each driving assistance is satisfied. The conditions for sounding an alarm are stored in a readable state for each driving assistance function in a storage device such as RAM 13 provided in processor 10. Processor 10 outputs the driving assistance conditions in text form as a reason for sounding an alarm. Examples of reasons for sounding an alarm associated with driving content or driving assistance are shown in FIG. 3. When processor 10 predicts that the driving content is reverse driving (or forward driving) or identifies the driving assistance as obstacle avoidance, processor 10 refers to the corresponding information and outputs a message stating that "there is an obstacle approaching behind (or in front of) the vehicle" as the reason. When processor 10 predicts that the driving content is overtaking driving or identifies the driving assistance as lane departure prevention, processor 10 refers to the corresponding information and outputs a message stating that "the vehicle is approaching a lane mark" as the reason. If the driving situation is predicted to be a lane-changing driving or if the driving assistance determines that a rear vehicle has been detected, the corresponding information is referenced and a message is output indicating that "there is a rear vehicle approaching the vehicle behind the vehicle on the lane-changing lane side."When the processor 10 predicts that the driving content is a right or left turn or when it identifies that the driving assistance is FEB with pedestrian / oncoming vehicle detection, it refers to the corresponding information and outputs a message indicating that "there is a pedestrian or an oncoming vehicle approaching the vehicle at the intersection." The identification of the driving assistance is based on the results of the prediction of the driving content.

[0026] Although not particularly limited, after the reason for issuing the warning sound is output in text, the processor 10 stores the details of the reason for issuing the warning sound, the date and time of the warning sound, etc. as a warning history in a storage device such as the RAM 13 (S8). S8 can be skipped. After the reason for issuing the warning sound is output in text, execution of the predicted driving operation is initiated (S9). When the host vehicle starts driving according to the driving operation, the processor 10 periodically determines whether the conditions for determining whether to issue a warning sound are met based on driving information including target detection information and the host vehicle's position (S13). The timing for starting the determination is not particularly limited. During driving assistance, the processor 10 periodically determines whether to issue a warning sound. Based on the proximity between the host vehicle and the target, if the conditions for issuing a warning sound are met (YES in S13), the processor 10 issues a warning sound (S14), and if the conditions are not met (NO in S13), the processor 10 does not issue a warning sound (S15). In this embodiment, the output process (S6) for the reason for issuing the warning sound is executed after the input of operation information (S2) and before the start of the predicted driving operation (S9). After the reason for issuing the warning sound is output in text, the predicted driving operation is executed. After outputting the reason for issuing the warning sound (S6), the processor 10 issues the warning sound if a predetermined condition is met (S14). In other words, the warning sound is not issued (S14) before the reason for issuing the warning sound is output (S6). When the driving assistance system is activated and a warning sound is suddenly issued as one of its functions, the occupants, including the driver, are surprised. The sudden issuance of the warning sound can make the occupants feel anxious, wondering, "What does this sound mean?" In particular, if the occupants are unaware of why the warning sound was issued, their anxiety tends to increase. Although this varies from person to person, a driver surprised by the warning sound may panic. At the very least, driving performed in a surprised state may be less appropriate than driving performed in a calm state without being surprised. This driving assistance system can provide the occupant with the reason (including the condition) for issuing a warning sound associated with the driving content predicted based on the driver's operation information, using text (words) before the warning sound is issued.Furthermore, this driving assistance system can identify driving assistance to be performed based on the predicted driving content, and provide the occupant with text (words) explaining the reason (including conditions) for issuing a warning sound associated with the identified driving assistance before the warning sound is issued. This avoids a situation in which a warning sound is issued suddenly, and reduces the occupant's surprise and the magnitude of that surprise. This can prevent the occupant from being surprised by a warning sound for driving assistance, which can disrupt the occupant's calm mental state and prevent the occupant from being able to drive normally. By communicating the reason (including conditions) for issuing a warning sound to the occupant using text (words) before the warning sound is issued, it can prevent the occupant from being surprised or confused by the warning sound. Because the reason for issuing a warning sound for each driving assistance is explained in advance in text, the occupant hears the warning sound after understanding the content of the driving assistance, and the occupant is not surprised by the warning sound.

[0027] Although not particularly limited, the processor 10 does not output the reason if the time difference between the timing when the driving content is predicted (S3) and the timing when the driving of the driving content is started (S9) is less than a predetermined value. If the prediction of the driving content and the start of the driving content are performed simultaneously or with a short time difference, the output of the reason may not be completed before the driving starts. If the vehicle and the target come close to each other while the reason is being explained and a warning sound is sounded, the occupants may feel annoyed. This process can avoid such a situation.

[0028] The processor 10 outputs the warning sound itself (the same sound as the actual warning sound) along with the reason for issuing the warning sound. The warning sound issued along with the reason is output at the beginning, middle, and end of the explanation of the reason. By outputting the warning sound along with the reason, the occupant learns in advance that "this kind of sound will be issued in this kind of situation." Because the warning sound to be issued is output in advance along with the reason for issuing the warning sound, it is possible to reduce the occupant's surprise when the actual warning sound is issued.

[0029] If the processor 10 predicts that the execution of the driving action will be stopped within a predetermined time from the timing (S3) when the driving action is predicted (YES in S10), it does not output a reason for issuing a warning sound (S12). For example, in obstacle avoidance support, if a gear shift is performed, for example, if the host vehicle's shift position is set to park, the processor 10 determines that forward / reverse driving of the host vehicle will be stopped. In lane departure prevention support, if the host vehicle's turn signal is input, the processor 10 determines that overtaking in the host vehicle's own lane will be stopped (a lane change will be executed). In rear vehicle detection support, if the host vehicle's brake operation is input, the processor 10 determines that lane change driving of the host vehicle will be stopped. This is because the host vehicle usually accelerates when a lane change is performed. In pedestrian / oncoming vehicle detection FEB support, if the host vehicle's turn signal input is canceled, the processor 10 determines that right / left turn driving of the host vehicle will be stopped. S10 and S12 are optional processes and can be skipped. If the driving conditions change, different driving assistance will be activated. In this process, if it is predicted that the driving conditions will be discontinued, the reason for issuing a warning sound will not be notified. The output of unnecessary information according to changes in driving conditions can be suppressed to prevent the occupants from feeling annoyed.

[0030] If the predicted driving behavior continues (NO in S10), the processor 10 refers to the output history of the reasons for issuing the warning sound recorded in S8. If the same reason has been output within a predetermined period of time (YES in S11), the reason for that content is not output again (S12). If the same reason has not been output within a predetermined period of time (NO in S11), the processor 10 executes the processing from S4 onwards. S11-12 are additional processes and can be skipped. The reasons output within a predetermined period of time in the past may remain in the occupant's memory. This processing prevents the same reason from being notified multiple times within a predetermined period of time. Repeated output of the same information is suppressed to prevent the occupant from feeling annoyed.

[0031] Figures 4(a), (b), and (c) show examples of driving assistance processes for obstacle avoidance, lane departure prevention, and rear vehicle detection. The flowchart and its explanation in Figure 2 are used for overlapping parts. Figure 4(a) shows an example of the obstacle avoidance driving assistance process. After S1 in Figure 2, the processor 10 acquires the input operation information (SA1, corresponding to S2 in Figure 2). If the shift is in reverse (YES in SA2), it predicts that the driving is reverse driving (SA3). If the shift is in drive (YES in SA4), it predicts that the driving is forward driving (SA5). Based on the predicted forward / backward driving, the processor 10 references the corresponding information and identifies the driving assistance as obstacle avoidance (SA6). The reason (condition) for issuing an obstacle avoidance warning sound is output as text (SA7). For example, as shown in FIG. 3, text information such as "An alarm will sound when approaching an obstacle behind or ahead," "A beep, beep, beep sound will sound when approaching an obstacle behind or ahead," or "Be careful of obstacles behind or ahead" is output as a reason for issuing the alarm before the alarm is issued (SA7, S7 in FIG. 2). This allows the user to know in advance the reason for issuing the alarm or the conditions for issuing the alarm. After SA7, the process proceeds to S8 in FIG. 2, where the output processing history is recorded, and then the driving content is executed (S9 in FIG. 2). FIG. 4(b) shows an example of a driving assistance process for preventing lane departure. After S21 in FIG. 2, processor 10 acquires detection information (SB1, corresponding to S22 in FIG. 2). If an obstacle is detected ahead (YES in SB2) and lane markings for the host vehicle's driving lane can be detected (YES in SB3), the process further acquires vehicle operation information (SB4, corresponding to S2 in FIG. 2). In this way, the order in which detection information and operation information are acquired is not limited. In driving situations where lane markings are detectable, driving assistance processing for lane departure prevention is executed. If operation information that does not include a turn signal input signal is acquired within a predetermined time, i.e., if no turn signal input signal is received (YES in SB5), processor 10 predicts that the driving is an overtaking operation (SB6). Based on the fact that the driving is an overtaking operation, processor 10 determines that the driving assistance is a lane departure prevention operation (SB7).The driving behavior is predicted based on the detection information indicating the presence of an obstacle ahead (YES in SB2) and the operational information indicating the absence of a turn signal input. Driving assistance is determined based on the predicted driving behavior and the driving scene indicating that lane markings are detectable (YES in SB3). If no obstacles ahead are detected (NO in SB2), lane markings are not detected (NO in SB3), or a turn signal input is made (NO in SB4), the driving behavior is not predicted as overtaking, and the process returns to SB1 and repeats the judgment. Processor 10 outputs the reason (condition) for issuing a lane departure prevention warning sound in text form (SB8). For example, as shown in Figure 3, text information such as "A warning sound will sound if there is a risk of approaching or deviating from the lane," "A beep-beep sound will sound if there is a risk of approaching or deviating from the lane," and "Pay attention to lane departure" is output before the warning sound is issued. After step SB8, the process proceeds to step S8 in FIG. 2, where the output processing history is recorded, and then the driving operation of the driving content is executed (step S9 in FIG. 2). Figure 4(c) shows an example of rear vehicle detection driving assistance. After step S21 in FIG. 2, processor 10 acquires detection information (SC1, corresponding to step S22 in FIG. 2). If a vehicle traveling at a low speed ahead is detected (YES in SC2) and the host vehicle is traveling on a road with two or more lanes (YES in SC3), it acquires vehicle operation information (SC4, corresponding to step S2 in FIG. 2). In a driving scenario where two or more lanes are detected, lane change driving assistance processing can be executed. If operation information that does not include a brake operation signal is acquired within a predetermined time, i.e., if no deceleration operation input is made (YES in SC5), processor 10 predicts that the driving content is lane change driving (SC6). Based on the fact that the driving content is lane change driving, processor 10 determines that the driving assistance is rear vehicle detection (SC7). The driving behavior is predicted based on the detection information indicating the presence of a slow-moving vehicle ahead (YES in SC2) and the operation information indicating the absence of brake operation input. Driving assistance is determined based on the predicted driving behavior and the driving scene where two or more lanes are detected (YES in SC3).If a slow-moving vehicle ahead is not detected (NO in SC2), if an adjacent lane is not detected (NO in SC3), or if a brake operation is input (NO in SC4), the driving action is not predicted as a lane change, and the process returns to SC1 and repeats the judgment. Processor 10 outputs the reason (condition) for issuing an audible warning when a rear vehicle is detected in text form (SC8). For example, as shown in Figure 3, text information such as "An audible warning will be issued if a rear vehicle approaches in the lane you are changing lanes to," "A beep will be issued if there is a risk of approaching a rear vehicle in the lane you are changing lanes to," and "Watch out for a rear vehicle in the lane you are changing lanes to" is output as the reason for issuing an audible warning before the actual issuance of the audible warning. After SC8, the process proceeds to S8 in Figure 2, where the output processing history is recorded, and then the driving action is executed (S9 in Figure 2).

[0032] Figure 5 shows examples of driving assistance processing for FEB with pedestrian detection and FEB with oncoming vehicle detection. The overlapping parts are referenced in the flowchart of Figure 2. This processing assumes vehicles keep on the left side of the road. After S21 in Figure 2, processor 10 acquires detection information (SD1, corresponding to S22 in Figure 2). If a T-shaped intersection exists within a predetermined range (within a predetermined distance) in the direction of travel of the vehicle (YES in SD2) and a pedestrian crossing exists (YES in SD9), the processing proceeds to SD10. If a T-shaped intersection does not exist within the predetermined range (within a predetermined distance) (NO in SD2), the processing proceeds to SD3. If a traffic light exists and the traffic light has a dedicated right / left turn signal function (so-called arrow signal function) that indicates whether or not passage is permitted for each left and right path (NO in SD3), processor 10 returns to SD1 without outputting the reason for issuing a warning sound. If the intersection has a traffic light without a dedicated right / left turn signal function (YES in SD3) and there is an intersection within a specified distance ahead (for example, within 30 m), proceed to SD5. If there is no intersection within the specified distance ahead, return to SD1 without outputting the reason for issuing a warning sound and repeat the process. In a driving scenario where the vehicle passes through an intersection without traffic lights indicating whether or not the vehicle can pass in each direction of travel (YES in SD3), the vehicle may approach an oncoming vehicle or pedestrian, causing an alarm to be issued. Furthermore, if the vehicle is traveling in the left-turn lane (YES in SD5) and there is a crosswalk (YES in SD9), proceed to SD10. If the vehicle is traveling in the right-turn lane (NO in SD5, YES in SD6), the vehicle is traveling in a city center (YES in SD8), and there is a crosswalk (YES in SD9), proceed to SD10. If the host vehicle is not traveling in a right / left turn lane (NO in SD5, NO in SD6) and no blinker operation information is obtained (NO in SD7), the process returns to SD1 without outputting the reason for issuing a warning sound. On the other hand, if blinker operation information is obtained (YES in SD7), the host vehicle is traveling in a city (YES in SD8), and there is a crosswalk (YES in SD9), the process proceeds to SD10. Even if the host vehicle is not traveling in a city (NO in SD8), if it is during school hours (YES in SD13) and there is a crosswalk (YES in SD9), the process proceeds to SD10. In SD10, processor 10 predicts that the host vehicle is turning right or left at an intersection and that there is a crosswalk (SD10).Based on the predicted driving behavior, processor 10 refers to the corresponding information and identifies the driving assistance as FEB with pedestrian detection (SD11). The driving behavior is predicted based on detection information indicating the presence of an intersection or crosswalk ahead, detection information indicating the vehicle will be traveling in a right- or left-turn lane, and operational information indicating the vehicle will operate its turn signal. The driving assistance is identified by referring to the corresponding information based on the predicted driving behavior and the driving scene indicating the vehicle will be passing through a crosswalk (YES in SD9). Processor 10 outputs the reason (condition) for issuing the FEB with pedestrian detection warning sound in text form (SD12). For example, text information such as "As shown in the corresponding information in Figure 3, a warning sound will be issued when a pedestrian approaches," "When an approaching pedestrian is detected, a 'beep, beep, beep' sound will be issued," and "Pay attention to where you are turning right or left" is output as the reason for issuing the warning sound before the warning sound is issued. After step SD12, the process proceeds to step S8 in FIG. 2, where the output processing history is recorded, and then the driving content is executed (step S9 in FIG. 2). If processor 10 predicts that the specified driving assistance will not be executed based on the predicted driving content, it does not output a reason for issuing an alarm. For example, processor 10 does not output a reason for issuing an alarm for the FEB with pedestrian detection if the intersection ahead of the vehicle is an intersection with a traffic light with a dedicated right / left turn signal function, or if the intersection does not have a crosswalk. By refraining from outputting a reason for issuing an alarm in situations where there is no possibility of approaching a pedestrian, the occupants are not annoyed.

[0033] If the host vehicle is not traveling in a turn lane (NO in SD5, NO in SD6) through SD1-SD4, but acquires blinker operation information (YES in SD7), is not traveling in a city (NO in SD8), and is not traveling during school hours when students are going to or from school (NO in SD13), proceed to SD14. Also, if the host vehicle is traveling in a right-turn lane (YES in SD6), is not traveling in a city (NO in SD8), and is not traveling during school hours when students are going to or from school (NO in SD13), proceed to SD14. At SD14, processor 10 predicts that the host vehicle will turn right or left at an intersection (SD14). Based on the predicted driving behavior, processor 10 determines that the driving assistance is FEB with oncoming vehicle detection (SD15). The driving behavior is predicted based on the detection information that an intersection is ahead (SD4) and that the host vehicle will be traveling in a turn lane (SD5-SD6), and the operation information that the blinker will be operated (SD7). Driving assistance is determined based on the predicted driving content and the driving scene indicating that the vehicle is driving in a right-turn lane under left-hand traffic rules (NO in SD5, YES in SD6). Processor 10 outputs the reason (condition) for issuing an audible warning when an oncoming vehicle is detected in text form (SD16). For example, as shown in Figure 3, text information such as "An audible warning will be issued when an oncoming vehicle approaches," "A 'beep, beep, beep' sound will be issued when an approaching oncoming vehicle is detected," and "Please be careful where you are turning right or left" is output before the audible warning is issued. In each of the above processing examples, the audible warning output along with the reason is the same as the actual audible warning. The audible warning can be different depending on the type of driving assistance. After processing SD16, the process proceeds to S8 in Figure 2, where the output processing history is recorded, and then the driving operation specified in the driving content is executed (S9 in Figure 2). In a driving scene in which the host vehicle passes through an intersection, when the host vehicle passes through an intersection where there is a traffic light equipped with a dedicated signal function for right and left turns (NO in SD3), the processor 10 determines that there is a low possibility of approaching an oncoming vehicle and that the FEB with oncoming vehicle detection is unlikely to operate, and does not output a reason for the event.By refraining from outputting a reason for issuing a warning sound in a scene in which there is no possibility of approaching an oncoming vehicle, the occupants are not inconvenienced.Although the example in FIG. 5 shows processing under traffic regulations that require vehicles to keep to the left, the processing can also be applied under traffic regulations that require vehicles to keep to the right.

[0034] 1... driving assistance device, 10... processor, 11... CPU, 12... ROM, 13... RAM, 20... output device, 201... speaker, 202... display, 30... input device, 40... communication device, 2... sensor, 21... camera, 22... radar device, 3... driving information acquisition device, 4... navigation device, 41... position detection device, 42... map information

Claims

1. A driving assistance method used in a processor, wherein when the processor executes driving assistance that issues a warning sound when the host vehicle approaches a predetermined target, the processor predicts the driving content of the host vehicle based on operation information input by the driver of the host vehicle, and after the input of the operation information and before the start of the execution of the predicted driving content, outputs the reason for the issuance of the warning sound in text based on the predicted driving content.

2. The processor executes the driving assistance that issues the warning sound when a predetermined condition defined in advance for each driving assistance is satisfied based on the degree of approach between the host vehicle and the target, and when executing the driving assistance, identifies the driving assistance executed based on the predicted driving content, and outputs the condition of the identified driving assistance as the reason for the issuance of the warning sound in the text. The driving assistance method according to claim 1.

3. The processor predicts that the driving content is a reverse driving based on the operation information in which the shift of the host vehicle is input to reverse, and outputs the existence of a rear obstacle approaching the host vehicle as the reason. The driving assistance method according to claim 1 or 2.

4. The processor predicts that the driving content is a forward driving based on the operation information in which the shift of the host vehicle is input to drive, and outputs the existence of a front obstacle approaching the host vehicle as the reason. The driving assistance method according to claim 1 or 2.

5. The processor acquires detection information around the host vehicle, and predicts the driving content based on the operation information and the detection information. The driving assistance method according to any one of claims 1 to 4.

6. The processor determines the driving scene of the host vehicle based on the detection information, and identifies the driving assistance based on the predicted driving content and the driving scene. The driving assistance method according to claim 5.

7. The processor predicts that the driving content is a passing operation based on the detection information in which an obstacle is detected in front of the host vehicle and the operation information that does not include the operation input of the turn signal of the host vehicle, and outputs the existence of a lane mark approaching the host vehicle as the reason. The driving assistance method according to claim 5 or 6.

8. The processor predicts that the driving content is a lane change operation based on the detection information indicating that another vehicle with a relative speed less than a predetermined value is detected in front of the host vehicle, and the operation information not including an operation input of the brake of the host vehicle, and outputs, as the reason, the presence of a rear vehicle approaching the host vehicle behind the lane side of the lane change. The driving support method according to claim 5 or 6.

9. The processor predicts that the driving content is a right / left turn operation based on the detection information indicating that an intersection exists in the traveling direction of the host vehicle, and the operation information including the turn signal operation of the host vehicle, and outputs, as the reason, the presence of a pedestrian approaching the host vehicle. The driving support method according to claim 5 or 6.

10. The processor predicts that the driving content is a right / left turn operation based on the detection information indicating that an intersection exists in the traveling direction of the host vehicle, and the operation information including the turn signal operation of the host vehicle, and outputs, as the reason, the presence of an oncoming vehicle approaching the host vehicle. The driving support method according to claim 5 or 6.

11. In the case where the time difference between the timing at which the driving content is predicted and the timing at which the driving of the driving content is started is less than a predetermined value, the processor does not output the reason. The driving support method according to any one of claims 1 to 10.

12. In the case where it is predicted that the execution of the driving content is aborted within a predetermined time from the timing at which the driving content is predicted, the processor does not output the reason. The driving support method according to any one of claims 1 to 11.

13. The processor stores the output history of the reason and does not output the reason of the same content again within a predetermined period. The driving support method according to any one of claims 1 to 12.

14. After outputting the reason, the processor issues the warning sound. The driving support method according to any one of claims 1 to 13.

15. The processor outputs the reason by voice text information or visible text information. The driving support method according to any one of claims 1 to 14.

16. The processor issues the warning sound together with the reason. The driving support method according to any one of claims 1 to 15.

17. A driving support device including a processor, wherein when executing driving support for reporting a warning sound when the host vehicle approaches a predetermined target, the processor predicts the driving state of the host vehicle based on operation information input by the driver of the host vehicle, and outputs, in text, the reason for reporting the warning sound based on the predicted driving state after the input of the operation information and before the start of execution of the driving of the predicted driving state.

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