Driving assistance devices for vehicles

Abstract

The present invention provides a vehicle driving assistance device that can identify a location where sudden acceleration needs to be suppressed in advance without using an obstacle recognition sensor, and appropriately suppress the occurrence of sudden acceleration caused by improper pedaling at the location. The device reads vehicle position information (S5) estimated by a vehicle position estimation calculation unit (12a), and based on the vehicle position information, refers to road map information in a road map database (16) to read road map information in front of the vehicle position (S6). It then checks whether there is an intersecting road in front of the vehicle M (S7), estimates whether the vehicle M is turning right or left at the intersecting road based on the direction of illumination of the turn signal lamp (S10), and executes acceleration suppression control (S17) to suppress sudden acceleration when turning right or left based on the azimuth angle difference Δψ formed by the azimuth of the vehicle M's traveling direction and the azimuth of the intersecting road in the right or left turn direction and the acceleration operation amount Pacc.

Description

Technical Field

[0001] The present invention relates to a vehicle driving assistance device that allows the degree of acceleration suppression of a host vehicle to be changed according to the azimuth angle difference between the azimuth of the host vehicle's traveling direction and the azimuth of an intersecting road at which the host vehicle is about to turn. Background Art

[0002] When the driver is about to slow down and stop the vehicle from a moving state or keep it parked, he or she may not notice that the accelerator pedal and brake pedal are not visible, and may mistakenly step on the accelerator pedal for the brake pedal, resulting in the driver continuing to step on the accelerator pedal.

[0003] As a countermeasure, there are commercially available devices that can be installed separately from the accelerator pedal to prevent treading errors, as well as single-pedal devices that integrate the accelerator and brake pedals and can be installed in place of the existing accelerator and brake pedals. However, retrofitting such devices imposes a financial burden on users. Furthermore, single-pedal devices require a certain amount of time to become accustomed to.

[0004] Therefore, for example, Patent Document 1 (Japanese Patent Publication No. 2014-227877) discloses the following technology: using existing sensor types such as vehicle speed sensors, obstacle detection sensors that detect obstacles in front, and accelerator position sensors (accelerator opening sensors) to detect the driving state and driving environment of the vehicle to detect pedaling errors.

[0005] That is, in the technology disclosed in this document, an obstacle detection sensor is used to investigate whether there is an obstacle that hinders the movement of the vehicle. If an obstacle is detected, the accelerator pedal's depression amount and depression speed detected by the accelerator position sensor are investigated to investigate whether they exceed a preset threshold value. If the threshold value is exceeded, the throttle opening is limited to prevent sudden acceleration.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-227877 Summary of the Invention

[0009] Technical issues

[0010] In the technology disclosed in the above-mentioned document, when an obstacle that hinders the vehicle's travel is not detected by the obstacle detection sensor, it is determined that it is not necessary to prevent sudden acceleration, and subsequent processing is not performed.

[0011] However, there are the following problems: for example, in places where sudden acceleration should be prevented, such as in environments such as heavy fog, rain, and snowfall where the obstacle detection sensor cannot fully detect obstacles, or in places where there is a T-junction ahead and there are no obstacles that should be detected, the function of preventing sudden acceleration caused by improper pedaling cannot be fully utilized.

[0012] It should be noted that this also applies when the driving mode is changed from the automatic driving mode to the driving assistance mode based on the well-known following distance control (ACC: Adaptive Cruise Control) and lane keeping (ALK: Active Lane Keep) control during automatic driving control.

[0013] In view of the above circumstances, an object of the present invention is to provide a vehicle driving assistance device that can identify in advance a location where sudden acceleration needs to be suppressed without using an obstacle recognition sensor and appropriately suppress the occurrence of sudden acceleration due to erroneous pedaling at that location.

[0014] Technical Solution

[0015] The present invention provides a vehicle driving assistance device, comprising: an acceleration suppression degree calculation unit for calculating an acceleration suppression degree for suppressing the acceleration of a host vehicle; and a driving state control unit for suppressing a target acceleration of the host vehicle based on the acceleration suppression degree calculated by the acceleration suppression degree calculation unit. The vehicle driving assistance device further comprises: a map information storage unit for storing road map information; a host vehicle position estimation unit for estimating a host vehicle position as the current position of the host vehicle and determining a driving lane on the road map information stored in the map information storage unit based on the host vehicle position; and a crossing lane. A road detection unit detects, based on the road map information stored in the map information storage unit, whether there is an intersecting road in front of the driving lane estimated by the vehicle position estimation unit; and an azimuth angle difference calculation unit calculates the azimuth angle difference between the azimuth of the intersecting road on which the vehicle is about to turn and the azimuth of the traveling direction of the vehicle when the intersecting road is detected by the intersecting road detection unit. The acceleration suppression degree calculation unit sets the acceleration suppression degree to become higher as the azimuth angle difference becomes smaller based on the azimuth angle difference calculated by the azimuth angle difference calculation unit.

[0016] Technical Effects

[0017] According to the present invention, a driving lane on the road map information stored in a map information storage unit is determined based on an estimated position of the vehicle, and whether there is an intersecting road in front of the driving lane is detected. When an intersecting road is detected, the azimuth difference between the azimuth of the intersecting road on which the vehicle is about to turn and the azimuth of the direction of travel of the vehicle is calculated. Based on the azimuth difference, the acceleration suppression degree is set to become higher as the azimuth difference becomes smaller, and the target acceleration is suppressed based on the acceleration suppression degree. Therefore, without using an obstacle recognition sensor, a place where sudden acceleration needs to be suppressed can be identified in advance, and the occurrence of sudden acceleration caused by incorrect stepping can be appropriately suppressed at that place. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an overall schematic diagram of the driving assistance system.

[0019] Figure 2 This is a flowchart (part 1) showing the acceleration suppression control routine.

[0020] Figure 3 This is a flowchart showing the acceleration suppression control routine (part 2).

[0021] Figure 4 This is a flowchart showing the acceleration suppression control routine (part 3).

[0022] Figure 5 This is a conceptual diagram of the azimuth angle difference threshold setting table.

[0023] Figure 6 This is a conceptual diagram of the accelerator operation amount threshold setting table.

[0024] Figure 7 (a) is a conceptual diagram of the acceleration suppression gain setting map based on the azimuth angle difference and the acceleration operation amount. Figure 7 (b) is a characteristic diagram showing the relationship between the accelerator operation amount and the target acceleration limited by the acceleration gain.

[0025] Figure 8 This is a conceptual diagram of an acceleration suppression gain setting table based on the lane width of an intersecting road.

[0026] Figure 9 This is an explanatory diagram showing acceleration suppression control when the vehicle is traveling straight or turning left.

[0027] Figure 10 This is an explanatory diagram showing acceleration suppression control when turning left or right at a T-intersection.

[0028] Figure 11 This is an explanatory diagram showing acceleration suppression control when turning left or right at a T-junction toward a narrow intersection.

[0029] Figure 12 This is an explanatory diagram showing acceleration suppression control when a vehicle is traveling in the direction of an intersecting road that intersects at an obtuse angle at a T-junction.

[0030] Figure 13 This is an explanatory diagram showing acceleration suppression control when a vehicle is traveling in the direction of an intersecting road at an acute angle at a T-junction.

[0031] Figure 14 This is an explanatory diagram showing acceleration suppression control when traveling from a priority road to a narrow branch road at a T-junction.

[0032] Explanation of symbols

[0033] 1: Driving assistance device

[0034] 11: Navigation unit

[0035] 12: Map positioning calculation unit

[0036] 12a: Vehicle position estimation calculation unit

[0037] 12b: Driving route setting calculation unit

[0038] 13: GNSS receiver

[0039] 14: Autonomous Sensors

[0040] 15: Route information input device

[0041] 16: Road map database

[0042] 21: Camera unit

[0043] 21a: Main camera

[0044] 21b: Secondary camera

[0045] 21c: Image Processing Unit (IPU)

[0046] 21d: Forward driving environment recognition unit

[0047] 31: Driving control unit

[0048] 32: Accelerator opening sensor

[0049] 33: Brake switch

[0050] 34: Vehicle speed sensor

[0051] 35: Steering angle sensor

[0052] 36: Turn indicator switch

[0053] 37: Brake drive unit

[0054] 38: Acceleration and deceleration drive unit

[0055] 39: Notification device

[0056] 41: Driving source

[0057] F: Acceleration suppression control release flag

[0058] Ka: acceleration gain

[0059] Li: arrival distance

[0060] Lia, Lib, Lic, Lid: Limit distance

[0061] M: This vehicle

[0062] Pac1: Acceleration operation threshold

[0063] Pac2: Accelerated release threshold

[0064] Pacc: Acceleration operation volume

[0065] WLANE: Lane Width

[0066] WLAO: Lane width threshold

[0067] Δψ: azimuth difference

[0068] ψo: azimuth angle difference threshold DETAILED DESCRIPTION

[0069] Hereinafter, an embodiment of the present invention will be described based on the accompanying drawings. Figure 9 、 Figure 11 、 Figure 13 、 Figure 14 In FIG. 1 , for convenience, the vehicle M is shown as traveling alone on a single-lane road. Figure 9 , the vehicle M traveling straight and the vehicle M turning left are shown in one figure.

[0070] Figure 1 The symbol 1 is a driving assistance device, which is mounted on the vehicle M (refer to Figures 9 to 14 The driving assistance device 1 includes a navigation unit 11, a camera unit 21, and a driving control unit 31.

[0071] The navigation unit 11 includes a map positioning calculation unit 12 and a road map database 16 serving as a map information storage unit. The map positioning calculation unit 12, the forward driving environment recognition unit 21d (described later), and the driving control unit 31 are composed of a well-known microcomputer including a CPU, RAM, ROM, and non-volatile storage, and its peripheral devices. The ROM stores programs executed by the CPU, data tables, maps, and other fixed data.

[0072] Connected to the input side of the map positioning calculation unit 12 are a GNSS (Global Navigation Satellite System) receiver 13, an autonomous sensor 14, and a route information input device 15. The GNSS receiver 13 receives positioning signals transmitted from multiple positioning satellites. Furthermore, the autonomous sensor 14 estimates the vehicle's position in environments where the sensitivity of receiving information from GNSS satellites is low, such as when driving in a tunnel, and positioning signals cannot be effectively received. The autonomous sensor 14 is composed of a vehicle speed sensor, a yaw rate sensor, and a longitudinal acceleration sensor. The map positioning calculation unit 12 performs positioning based on the distance traveled and the direction, using the vehicle speed detected by the vehicle speed sensor, the yaw rate (yaw angular velocity) detected by the yaw rate sensor, and the longitudinal acceleration detected by the longitudinal acceleration sensor.

[0073] The route information input device 15 is a terminal device operated by the driver and passengers. The route information input device 15 can collectively input a series of information required for setting a driving route in the map positioning calculation unit 12, such as the destination and intermediate points (such as service areas on highways).

[0074] Specifically, the route information input device 15 is a touch panel of a display included in the navigation unit 11 , a mobile terminal represented by a smartphone, a personal computer, or the like, and is connected to the map positioning calculation unit 12 via a wired or wireless connection.

[0075] When a driver or passenger operates the route information input device 15 and inputs information of a destination or a stopover point (facility name, address, telephone number, etc.), the input information is read by the map positioning calculation unit 12 .

[0076] When a destination or a stopover point is input, the map positioning calculation unit 12 sets the position coordinates (latitude and longitude) thereof. The map positioning calculation unit 12 includes a vehicle position estimation calculation unit 12a, which estimates the current position of the vehicle M, i.e., the vehicle position, and determines the lane in which the vehicle M is traveling; and a driving route setting calculation unit 12b, which sets a driving route from the vehicle position to the destination (and the stopover point).

[0077] The road map database 16 is a large-capacity storage medium such as an HDD and stores known road map information. This road map information includes information indicating road conditions such as road type (general road, expressway, etc.), road shape, road direction, lane width, and intersections (crossroads, T-junctions).

[0078] The vehicle position estimation operation unit 12a obtains the current position coordinates (latitude, longitude) of the vehicle M based on the positioning signal received by the GNSS receiver 13, and matches the position coordinates to the map information to estimate the vehicle position (current position) on the road map, and determines the driving lane, and then calculates the direction of travel (vehicle direction) based on the movement history of the vehicle position.

[0079] Furthermore, in an environment where the sensitivity of the GNSS receiver 13 decreases and effective positioning signals from positioning satellites cannot be received, such as when traveling in a tunnel, the vehicle position estimation calculation unit 12 a performs positioning based on information from the autonomous sensor 14 as described above.

[0080] The driving route setting calculation unit 12b refers to the road map information stored in the road map database 16 based on the position information (latitude and longitude) of the vehicle position estimated by the vehicle position estimation calculation unit 12a and the position information (latitude and longitude) of the input destination (and via point). The driving route setting calculation unit 12b then constructs a driving route connecting the vehicle position and the destination (or, if via points have been set, the destination via the via points) on the road map information, based on pre-set route conditions (such as a recommended route and a fastest route).

[0081] Meanwhile, the camera unit 21 is fixed to the upper center of the front interior of the vehicle M. It includes an onboard camera (stereo camera) consisting of a main camera 21a and a sub-camera 21b, which are arranged at bilaterally symmetrical positions across the center in the vehicle width direction (the center of the vehicle width), an image processing unit (IPU) 21c, and a forward driving environment recognition unit 21d. The camera unit 21 captures reference image data using the main camera 21a and captures comparison image data using the sub-camera 21b.

[0082] The IPU 21c then processes these two image data sets in a predetermined manner. The forward driving environment recognition unit 21d reads the reference image data and comparison image data processed by the IPU 21c, identifies the same object in the two images based on their parallax, and calculates the distance data (the distance from the vehicle M to the object) using the principle of triangulation to recognize forward driving environment information.

[0083] This forward driving environment information includes the road shape (left and right lane lines, the road curvature [1 / m] between the lane lines, and the width between the left and right lane lines (lane width)) of the lane (driving lane) in which the vehicle M is traveling, intersections, traffic lights, road signs, and forward obstacles (crossing pedestrians, bicycles, utility poles, telephone poles, parked vehicles, etc.). These obstacles are identified using methods such as well-known pattern matching. Therefore, the camera unit 21 functions as an obstacle recognition sensor.

[0084] This forward driving environment information is read by a driving control unit 31. The forward driving environment recognition unit 21d of the camera unit 21 and the map positioning calculation unit 12 are connected to the input side of the driving control unit 31. Also connected to the input side are an accelerator opening sensor 32, which serves as an accelerator operation amount detection unit and detects the accelerator pedal operation amount (accelerator operation amount) Pacc[deg]; a brake switch 33, which is activated by depression of the brake pedal; a vehicle speed sensor 34 included in the autonomous sensor 14; a steering angle sensor 35, which detects the steering angle of the steering wheel operated by the driver; and a turn signal switch 36, which the driver activates to flash the right turn indicator or the left turn indicator when turning right or left.

[0085] On the other hand, connected to the output side of the driving control unit 31 are a brake driver 37 that decelerates the vehicle M through forced braking to avoid collision with an object; an acceleration / deceleration driver 38 that limits the output of a drive source 41 such as an engine and / or motor as needed based on the driver's accelerator operation amount; and a notification device 39 such as a display and a speaker that notifies the driver of a message urging caution. It should be noted that the driving control unit 31 can activate the brake driver 37 to brake each of the four wheels individually.

[0086] When an obstacle that may collide with the vehicle M is detected in the direction of the vehicle M based on the driver's steering wheel operation, the driving control unit 31 prompts the driver's attention through the notification device 39, and then assists the driver's steering wheel operation by performing a collision avoidance action through the vehicle integrated control of the braking drive unit 37 and the acceleration and deceleration drive unit 38 that brakes the four wheels individually.

[0087] Furthermore, the driving control unit 31 reads the road condition of the direction in which the vehicle M is traveling at the intersection according to the driver's steering wheel operation from the road map information stored in the road map database 16, and performs acceleration suppression control as needed to suppress sudden acceleration caused by incorrect depression of the brake pedal and accelerator pedal.

[0088] Specifically, the acceleration suppression control executed by the driving control unit 31 is performed according to Figures 2 to 4 The acceleration suppression control routine shown in FIG. 1 is used to process the acceleration suppression control routine. It should be noted that the following description is based on an example of a road where left-hand traffic is specified. Therefore, on a road where right-hand traffic is specified, the left side is replaced by the right side.

[0089] This routine first reads forward driving environment information identified by the forward driving environment recognition unit 21d of the camera unit 21 in step S1. The routine then proceeds to step S2, where it checks whether there are any potential obstacles ahead. If no potential obstacles are identified, the routine proceeds to step S3. If a potential obstacle is identified, the routine branches to step S4. If the routine branches to step S4, collision avoidance control based on known integrated vehicle control is executed by the braking drive unit 37 and the acceleration / deceleration drive unit 38 to avoid collision with the obstacle, and the routine then exits.

[0090] Meanwhile, in step S3, the value of the acceleration suppression control release flag F is referenced. This acceleration suppression control release flag F is set in step S20, described later, and cleared in step S26. If F = 1, the process branches to step S25. On the other hand, if F = 0, the process proceeds to step S5 to execute acceleration suppression control.

[0091] In step S5, the vehicle position information estimated by the vehicle position estimation calculation unit 12a of the map positioning calculation unit 12 is read. In step S6, the road map information of the road map database 16 is referenced and the road map information ahead of the vehicle position is read based on the vehicle position information.

[0092] Then, the process proceeds to step S7, where the presence of an intersecting road is checked based on the road map information ahead of the vehicle position. Here, the distance ahead of the vehicle position is the distance at which the driver turns on the turn signal switch 36 to turn left or right, for example, within 30 to 20 [m], but not limited to this. In addition, an intersecting road refers to another road connected to the road on which the vehicle M is traveling. Figure 9 The intersection shown and Figure 10 The other road at the T-junction shown is a representative example, and further, the road connected to the parking lot is also included in the intersecting roads. It should be noted that the processing in step S7 corresponds to the intersecting road detection unit of the present invention.

[0093] If an intersecting road is detected, the routine proceeds to step S8. If no intersecting road is detected, the routine exits immediately. If the turn signal switch 36 is detected in step S8, the routine checks whether it is on. If it is off, the routine branches to step S9. If it is on, the routine proceeds to step S10.

[0094] If the process branches to step S9, the vehicle M is checked based on the road map information to see whether the vehicle M is traveling in a lane that crosses the intersecting road and is traveling straight. Figure 10In the case of a T-junction as shown, the process jumps to step S11. In this case, it can be considered that the driver is about to turn right or left without turning on the turn signal switch 36.

[0095] On the other hand, in Figure 9 When straight roads continue like the intersection shown, it can be assumed that the driver will go straight. Therefore, since acceleration suppression control is not necessary, the routine is exited.

[0096] In this case, if Figure 9 、 Figure 10 As shown, when the field of view ahead of the vehicle M is not sufficiently ensured due to dense fog, rain, snow, etc., it is not possible to clearly determine whether the straight road is continuous based on the forward driving environment information acquired by the camera unit 21 .

[0097] In addition, even if the field of view is ensured, in the case of Figure 10 At the T-junction shown, if there is no obstacle such as a guardrail in front of the crossroad, the front driving environment information obtained by the camera unit 21 cannot determine whether the straight road is continuous or has a height difference such as a pier or cliff.

[0098] Consequently, sudden acceleration caused by erroneous depression of the brake and accelerator pedals cannot be sufficiently suppressed at locations where it is originally necessary. Therefore, in this embodiment, it is checked based on road map information whether the driving lane of the host vehicle M crosses the intersecting road and continues on the straight road.

[0099] If the turn signal switch 36 is determined to be on and the process proceeds to step S10, the direction indicator is checked to determine whether the vehicle M is turning right or left. If the right turn signal is on, the process proceeds to step S11, while if the left turn signal is on, the process branches to step S12. The processing in this step corresponds to the left or right turn prediction unit of the present invention.

[0100] If the process proceeds from step S9 or step S10 to step S11, the distance Li from the vehicle position of the host vehicle M to the right-turn lane of the intersecting road (hereinafter referred to as the "right-turn intersecting lane") is calculated based on the road map information. In addition, if the process branches to step S12, the distance Li from the vehicle position of the host vehicle M to the left-turn lane of the intersecting road (hereinafter referred to as the "left-turn intersecting lane") is calculated based on the road map information. In this case, Figure 10 As shown, in this embodiment, the position of the crossing lane is set to the center of the lane width WLANE (WLANE / 2). Therefore, in left-hand traffic, the reaching distance Li to the right-turn crossing lane is longer than the reaching distance Li to the left-turn crossing lane.

[0101] This is in Figure 9 、 Figure 11 As shown in FIG, the same is true when the driver is about to turn the vehicle M right or left at the intersection of the intersection. Figures 12 to 14 As shown, when the intersecting road intersects at an angle, the reach distance Li is the distance to the position where the traveling direction of the host vehicle M intersects the intersecting lane. The processing in steps S11 and S12 corresponds to the reach distance calculation unit of the present invention.

[0102] However, even if the turn signal switch 36 is off in step S8, if it is determined in step S9 that the straight road is discontinuous ahead of the intersecting road, it can be inferred that the driver is turning the vehicle M right or left. In this case, since the reach distance Li to the intersecting lane is longer for a right turn than for a left turn, the reach distance Li to the right-turn intersecting lane is calculated first. As will be described later, acceleration suppression control becomes stronger as the reach distance Li decreases. Therefore, if acceleration suppression control is based on the reach distance Li to the left-turn intersecting lane, the driver may be forced to suppress acceleration more than necessary when about to turn right, causing discomfort to the driver.

[0103] Next, the process proceeds to step S13, where the azimuth angle difference threshold value ψo[deg] and the acceleration operation amount threshold value Pac1[deg] are set based on the arrival distance Li by table search. Figure 12 、 Figure 13 As shown, the azimuth angle difference Δψ[deg] is the intersection angle formed by the direction of the vehicle M's traveling direction and the road direction on the side of the intersection road to be turned. Figure 9 The intersection shown, Figure 10 The T-junction shown has Δψ = 90 [deg].

[0104] Figure 5 The concept of the azimuth angle difference threshold value setting table is shown. As shown in the figure, the azimuth angle difference threshold value ψo is set to a value that becomes higher as the arrival distance Li becomes shorter. By the way, the distance (limit distance) Lia at which the azimuth angle difference threshold value ψo is constant is about 5 [m], and the limit distance Lib at a distance is about 30 [m]. Generally, as the azimuth angle difference Δψ becomes smaller, it is necessary to slow down as soon as possible and turn the vehicle M at a lower speed at the intersection. Therefore, the azimuth angle difference threshold value ψo is set to a value that becomes smaller as the arrival distance Li becomes longer, and when the azimuth angle difference Δψ is greater than the threshold value ψo, acceleration is suppressed. Therefore, when the azimuth angle difference Δψ is small, the time to suppress acceleration becomes earlier than when the azimuth angle difference Δψ is large.

[0105] in addition, Figure 6This figure shows the concept of the accelerator operation amount threshold setting table. As shown in the figure, the accelerator operation amount threshold Pac1 is set to a value that decreases as the arrival distance Li decreases. Incidentally, the short-distance limit Lic is approximately 10 [m], and the long-distance limit Lid is approximately 50 [m]. Typically, the driver sets the speed at which their vehicle M will turn at the intersection by visually targeting the intersection, and then decelerates from a distance to achieve that speed. In this case, the driver first releases the accelerator pedal at a distance to decelerate, and then presses the brake pedal to forcibly decelerate. Therefore, mistakenly pressing the brake pedal and the accelerator pedal occurs when the accelerator pedal is mistakenly pressed for the brake pedal.

[0106] Furthermore, if the accelerator pedal is mistakenly depressed as the brake pedal and the vehicle M suddenly accelerates, the driver may further depress the accelerator pedal in an attempt to stop the vehicle M. Therefore, the accelerator operation amount threshold value Pac1 is set in the accelerator operation amount threshold value setting table to a value that decreases as the arrival distance Li decreases, thereby suppressing acceleration as quickly as possible.

[0107] Then, the process proceeds to step S14, where the azimuth angle difference Δψ between the vehicle's orientation obtained based on the vehicle's movement history and the orientation of the road on the side of the intersection road where the vehicle is about to turn is obtained. Figure 12 、 Figure 13 As shown, when the road (driving lane) of the host vehicle M is connected at an angle to the intersecting road, the heading angle difference Δψ takes on different values ​​depending on the direction in which the host vehicle M is turning. Therefore, when calculating this heading angle difference Δψ, the determination result in step S10 is referenced to predict whether the host vehicle M is turning right or left. The processing in step S14 corresponds to the heading angle difference calculation unit of the present invention.

[0108] Next, the routine proceeds to step S15, where the azimuth angle difference Δψ is compared with the azimuth angle difference threshold value ψo. If the azimuth angle difference Δψ is less than the azimuth angle difference threshold value ψo (Δψ ≤ ψo), the routine proceeds to step S16. If the azimuth angle difference Δψ is greater than the azimuth angle difference threshold value ψo (Δψ > ψo), acceleration suppression is determined to be unnecessary, and the routine exits.

[0109] Once the process proceeds to step S16, the accelerator operation amount Pacc detected by the accelerator opening sensor 32 is compared with the accelerator operation amount threshold value Pac1. If the accelerator operation amount Pacc is greater than the accelerator operation amount threshold value Pac1 (Pacc>Pac1), the process proceeds to step S17. If the accelerator operation amount Pacc is less than the accelerator operation amount threshold value Pac1 (Pacc≤Pac1), it is determined that acceleration suppression is not necessary, and the routine exits. Thus, if Δψ>ψo or Pacc≤Pac1, acceleration suppression control is not executed, thereby preventing the driver from experiencing a sense of discomfort due to insufficient acceleration.

[0110] If the process proceeds to step S17 , acceleration suppression control is executed based on the azimuth angle difference Δψ and the accelerator operation amount Pacc, and the process proceeds to step S18 .

[0111] This acceleration suppression control sets the acceleration gain Ka [%] as the degree of acceleration suppression based on the azimuth angle difference Δψ and the accelerator operation amount Pacc with reference to the acceleration gain map. The concept of the acceleration gain map is shown in Figure 7 As shown in the figure, the acceleration gain Ka is gradually set to a value that increases the degree of acceleration suppression (reduces the acceleration gain Ka) as the acceleration operation amount Pacc changes from a small value to a large value and the azimuth angle difference Δψ changes from a large value to a small value, and the minimum degree is Ka = 100 [%].

[0112] For example, Figure 14 As shown, if the roads intersect at angles other than 90 degrees, when the vehicle M traveling downward from the top of the figure is about to turn right, or when the vehicle M traveling upward from the bottom of the figure is about to turn left, the vehicle M about to turn left must further decelerate when entering the intersection. Therefore, to suppress sudden acceleration caused by inadvertent pedaling, the acceleration gain Ka for suppressing acceleration must be set to a value that decreases as the heading angle difference Δψ decreases.

[0113] On the other hand, when the driver recognizes a right or left turn intersection ahead while operating the host vehicle M, the accelerator operation amount Pacc adjusts the speed at which the driver reaches the intersection by releasing the accelerator pedal and applying the brakes at a predetermined time. To suppress sudden acceleration caused by accidental pedaling, the acceleration increases as the accelerator operation amount Pacc increases, so the acceleration gain Ka needs to be set to a smaller value. Figure 7 The characteristics of the acceleration gain map shown in (a) are set in advance based on simulations, etc., and can be changed as appropriate. Then, the acceleration gain Ka set based on the acceleration gain map is used to limit the target acceleration for the drive source 41 set by the driving control unit 31, thereby suppressing the actual acceleration.

[0114] That is, based on the acceleration operation amount Pacc and the vehicle speed detected by the vehicle speed sensor 34, a target acceleration is set by referring to an acceleration / deceleration map (not shown in the figure). In this acceleration / deceleration map, the greater the acceleration operation amount Pacc and the lower the vehicle speed, the greater the value of the set target acceleration. Then, the acceleration gain Ka is multiplied by the set target acceleration to set a suppressed target acceleration. Therefore, as shown in (b) of Figure 7 , for the acceleration operation amount Pacc when the driver steps on the accelerator pedal starting from a stop state (vehicle speed = 0 [Km / h]), the target acceleration is set to a value suppressed according to the acceleration gain Ka.

[0115] As a result, when the vehicle M approaches an intersection or enters an arterial road from a parking lot, even if the accelerator pedal is misstepped as a brake pedal and stepped on forcefully, sudden acceleration can be prevented because the target acceleration is suppressed. It should be noted that the processing in the above steps S13 to S17 corresponds to the acceleration suppression degree calculation unit of the present invention.

[0116] The travel control unit 31 calculates a drive torque corresponding to the suppressed target acceleration, and outputs a drive signal corresponding to the drive torque from the acceleration / deceleration drive unit 38 to the drive source (engine, motor, etc.) 41 to make the vehicle M travel. Therefore, the travel control unit 31 has the function of the travel state control unit of the present invention.

[0117] Next, if step S18 is entered, the acceleration operation amount Pacc is compared with an acceleration release determination threshold Pac2. This acceleration release determination threshold Pac2 is a value for determining whether the driver has released the stepping on the accelerator pedal, and is set to be close to Pacc = 0 [deg].

[0118] Then, when Pacc ≥ Pac2, step S19 is entered. On the other hand, when Pacc < Pac2, it is determined that the driver has consciously released the accelerator pedal, and the routine branches to step S20, the acceleration suppression control release flag F is set (F ← 1), and the routine exits. The value of this acceleration suppression control release flag F is read in the above step S4, and when F = 1, the routine branches to step S25.

[0119] If step S19 is entered, it is investigated whether the vehicle M turns right or left and turns in the direction of the cross lane. Based on the steering angle of the steering wheel detected by the steering angle sensor 35, the yaw rate detected by the yaw rate sensor, or the relationship between the change in the azimuth of the vehicle position in the road map information of the road map database 16 during map matching and the travel lane, etc., it is investigated whether the vehicle M is turning. It should be noted that the processing in this step corresponds to the turning detection unit of the present invention.

[0120] If no turning of the vehicle M is detected, the process returns to step S17 and the processes of steps S17 to S19 are repeated until a turn toward the intersecting lane is detected. If a turn is detected in step S19, the process proceeds to step S21.

[0121] In step S21, the lane width WLANE of the intersecting road in the direction of travel is acquired by referring to the road map information in the road map database 16. Alternatively, if the left and right lane markings that demarcate the intersecting road in the direction of travel are identified based on the forward driving environment acquired by the forward driving environment recognition unit 21d of the camera unit 21, the lane width WLANE can be calculated based on the distance between these lane markings. The processing in this step corresponds to the lane width acquisition unit of the present invention.

[0122] Next, the process proceeds to step S22 , where the lane width WLANE is compared with a preset lane width threshold WLAO. This lane width threshold WLAO is the lower limit of the lane width within which the host vehicle M can pass with a margin, and is set according to the width of the host vehicle M. For example, if the lane width threshold WLAO is set to approximately twice the vehicle width, and the width of the host vehicle M is 1800 mm, the lane width threshold WLAO is set to approximately 3600 mm.

[0123] If WLANE > WLAO, acceleration suppression control is determined to be unnecessary and the routine exits. On the other hand, if WLANE ≤ WLAO, the process proceeds to step S23, where acceleration suppression control during cornering is executed. However, even if WLANE > WLAO, if the front driving environment recognition unit 21d of the camera unit 21 detects a potential obstacle (such as a curb, utility pole, telephone pole, parked vehicle, guardrail, or wall) in front of the vehicle during cornering, collision avoidance control is executed in step S4. Therefore, even if the accelerator pedal is mistakenly pressed for the brake pedal, sudden acceleration will not occur.

[0124] In step S23 , acceleration suppression control during turning is executed. In this acceleration suppression control, first, an acceleration gain Ka is set by referring to an acceleration suppression gain setting table based on the lane width WLANE in the traveling direction of the intersecting road. Figure 8 This table represents the concept of the acceleration suppression gain setting table. This acceleration gain Ka is proportional to the lane width WLANE and is set to a lower value as the lane width WLANE narrows. Specifically, when turning the host vehicle M, the narrower the lane width WLANE, the more it is necessary to suppress sudden acceleration caused by accidental stepping on the vehicle.

[0125] Then, the acceleration gain Ka is multiplied by the above-mentioned target acceleration to set the suppressed target acceleration. As a result, even when the driver missteps and forcefully steps on the accelerator pedal as if it were the brake pedal while turning the vehicle M in the lane direction of the intersection road, since, as shown in (b) of Figure 7 the target acceleration is suppressed according to the lane width WLANE, it is possible to prevent sudden acceleration when entering a narrow lane.

[0126] After that, step S24 is entered to investigate whether the vehicle orientation is the same as the road orientation of the traveling direction of the intersection road. For example, it is investigated whether the vehicle orientation is the same as the road orientation by determining whether the vehicle orientation obtained from the movement history of the vehicle position is the same as the road orientation obtained from the road map information. Alternatively, it is investigated by whether the traveling direction of the vehicle M is parallel to the lane lines dividing the left and right of the driving lane recognized by the camera unit 21.

[0127] Then, when the vehicle orientation and the road orientation do not match, the process returns to step S23 and the acceleration suppression control is repeatedly executed. In addition, when the vehicle orientation and the road orientation match, the routine is exited and the acceleration suppression control is ended.

[0128] On the other hand, if the process branches from step S3 to step S25, it is investigated whether the vehicle orientation is the same as the road orientation of the traveling direction of the intersection road. Since whether the vehicle orientation is the same as the road orientation of the traveling direction of the intersection road is the same as the processing in step S24 above, the description is omitted.

[0129] In this acceleration suppression control routine, if the driver releases the accelerator pedal (Pacc < Pac2), the acceleration suppression control release flag F is set (F ← 1) in step S20. As a result, the acceleration suppression control is not executed and the process branches from step S3 to step S25, so the acceleration suppression control is substantially released. Therefore, the processing in steps S18 and S20 corresponds to the acceleration suppression control release detection unit of the present invention.

[0130] Then, if it is determined in step S25 that the vehicle orientation is the same as the road orientation of the traveling direction of the intersection road, step S26 is entered, the acceleration suppression control release flag F is cleared (F ← 0), and the routine is exited.

[0131] Therefore, when the driver releases the accelerator pedal during the acceleration suppression control, the acceleration suppression control is automatically released. Therefore, if the driver steps on the accelerator pedal again, i.e.,所谓的二次踩踏, it is determined that the driver stepped on the accelerator pedal consciously, and the normal target acceleration corresponding to the operation amount of the driver's accelerator pedal is set (corresponding to Figure 7 Ka = 100 [%] in (b) of

[0132] In this way, according to this embodiment, the environment ahead that cannot be recognized by the camera unit 21 is obtained from the road map information, and it is investigated whether there is a straight road that is continuous with the lane in front of the intersection. When the straight road is not continuous, acceleration suppression control is performed. Therefore, without using an obstacle recognition sensor, the place where sudden acceleration needs to be suppressed can be identified in advance, and the occurrence of sudden acceleration caused by erroneous stepping can be appropriately suppressed at this place.

[0133] In addition, based on the arrival distance Li between the vehicle M and the intersection lane of the intersection road, the azimuth angle difference threshold ψo and the acceleration operation amount threshold Pac1 are set, and compared with the azimuth angle difference Δψ and the acceleration operation amount Pacc. When Δψ>ψo or Pacc≤Pac1, the acceleration suppression control is not performed. Therefore, the driver will not feel a sense of disharmony due to insufficient acceleration.

[0134] Furthermore, when the accelerator pedal is depressed a second time, it is determined that the acceleration request is in accordance with the driver's intention, and the acceleration suppression control is not executed. Therefore, traveling more in accordance with the driver's intention can be performed.

[0135] It should be noted that the present invention is not limited to the above-mentioned embodiment, and can also be applied, for example, when the driving mode in an autonomous vehicle is switched from an autonomous driving mode to a manual driving mode in which the driver operates the steering wheel.

Claims

1. A driving assistance device for a vehicle, characterized in that: have: an acceleration suppression degree calculation unit that obtains an acceleration suppression degree for suppressing acceleration of the host vehicle; and a running state control unit that suppresses a target acceleration of the host vehicle based on the acceleration suppression degree calculated by the acceleration suppression degree calculation unit, The vehicle driving assistance device further includes: A map information storage unit for storing road map information; a vehicle position estimating unit that estimates a vehicle position as a current position of the vehicle and determines a driving lane on the road map information stored in the map information storage unit based on the vehicle position; an intersecting road detecting unit that detects, based on the road map information stored in the map information storing unit, whether there is an intersecting road ahead of the driving lane estimated by the vehicle position estimating unit; as well as an azimuth difference calculating unit for calculating an azimuth difference between the azimuth of the intersecting road on which the host vehicle is about to turn and the azimuth of the traveling direction of the host vehicle when the intersecting road is detected by the intersecting road detecting unit; The acceleration suppression degree calculation unit sets the acceleration suppression degree to be higher as the azimuth angle difference is smaller, based on the azimuth angle difference calculated by the azimuth angle difference calculation unit. The vehicle driving assistance device further includes a distance calculation unit for calculating a distance from the host vehicle to the intersection road. The acceleration suppression degree calculation unit sets an azimuth angle difference threshold value, which becomes higher as the arrival distance becomes shorter, based on the arrival distance calculated by the arrival distance calculation unit, and sets the acceleration suppression degree based on the azimuth angle difference when the azimuth angle difference calculated by the azimuth angle difference calculation unit is less than the azimuth angle difference threshold value.

2. The vehicle driving assistance device according to claim 1, wherein: The vehicle driving assistance device further includes an accelerator operation amount detection unit that detects the operation amount of the accelerator pedal. The acceleration suppression degree calculation unit sets the acceleration suppression degree to be higher as the azimuth angle difference decreases and the accelerator pedal operation amount increases based on the azimuth angle difference calculated by the azimuth angle difference calculation unit and the accelerator pedal operation amount detected by the accelerator operation amount detection unit.

3. The vehicle driving assistance device according to claim 2, wherein: The vehicle driving assistance device further includes a distance calculation unit for calculating a distance from the host vehicle to the intersection road. The acceleration suppression degree calculation unit sets an acceleration operation amount threshold value, which becomes lower as the arrival distance becomes shorter, based on the arrival distance calculated by the arrival distance calculation unit, and sets the acceleration suppression degree based on the operation amount of the accelerator pedal when the operation amount of the accelerator pedal detected by the acceleration operation amount detection unit is greater than the acceleration operation amount threshold value.

4. The vehicle driving assistance device according to claim 1, wherein: The vehicle driving assistance device further comprises: a turning detection unit that detects a turning of the host vehicle toward the intersecting road; and a lane width acquiring unit, which acquires the lane width of the intersecting road; When the turn detection unit detects a turn toward the intersecting road, the acceleration suppression degree calculation unit sets the acceleration suppression degree to be higher as the lane width becomes narrower based on the lane width of the intersecting road acquired by the lane width acquisition unit.

5. The vehicle driving assistance device according to any one of claims 1 to 4, characterized in that: The vehicle driving assistance device further includes a right or left turn prediction unit for predicting whether the vehicle will turn right or left at the intersection. The heading angle difference calculation unit calculates the heading angle difference based on an intersection angle formed by the heading of the host vehicle and the heading of the right turn or left turn direction predicted by the right or left turn prediction unit.

6. The vehicle driving assistance device according to any one of claims 1 to 4, characterized in that: The vehicle is an autonomous driving vehicle. When the driving mode of the autonomous vehicle is changed from the autonomous driving mode to the manual driving mode in which the driver operates the steering wheel, the acceleration suppression degree calculation unit is used to calculate the acceleration suppression degree. The traveling state control unit suppresses acceleration of the host vehicle based on the acceleration suppression degree calculated by the acceleration suppression degree calculation unit.

7. The vehicle driving assistance device according to claim 5, wherein: The vehicle is an autonomous driving vehicle. When the driving mode of the autonomous vehicle is changed from the autonomous driving mode to the manual driving mode in which the driver operates the steering wheel, the acceleration suppression degree calculation unit is used to calculate the acceleration suppression degree. The traveling state control unit suppresses acceleration of the host vehicle based on the acceleration suppression degree calculated by the acceleration suppression degree calculation unit.

8. The vehicle driving assistance device according to claim 1, wherein: The vehicle driving assistance device further comprises: an accelerator operation amount detecting unit that detects an operation amount of an accelerator pedal; and an acceleration suppression control release detection unit that detects the release of the accelerator pedal based on the operation amount of the accelerator pedal detected by the accelerator operation amount detection unit, The traveling state control unit cancels acceleration suppression of the target acceleration when the acceleration suppression control cancellation detection unit detects release of the accelerator pedal.

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