Driving assistance devices for vehicles

Abstract

The present invention provides a vehicle driving assistance device capable of pre-identifying locations where sudden acceleration suppression is necessary and appropriately suppressing sudden acceleration caused by improper pedaling at those locations. The device reads vehicle position information estimated by a vehicle position estimation calculation unit, and based on this vehicle position information, references road map information from a road map database to read road map information ahead of the vehicle position. The device then checks whether there is an intersecting road ahead of the vehicle M. Based on the direction of the turn signal, it predicts whether the vehicle M will turn right or left at the intersecting road. Based on the predicted right or left turn of the vehicle M, a prohibited driving zone is set along the intersecting road. Based on the distance Li from the vehicle M to the prohibited driving zone, an acceleration gain Ka for suppressing acceleration is set. This acceleration gain Ka is used to correct a basic target acceleration αbs to set a target acceleration α.

Description

Technical Field

[0001] The present invention relates to a vehicle driving assistance device that suppresses acceleration of a host vehicle according to road conditions even when no obstacle is detected ahead of the host vehicle in its traveling direction. 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 the brake pedal are not visible, and may mistakenly step on the accelerator pedal instead of 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, the following technology is disclosed in Patent Document 1 (Japanese Patent Gazette No. 2014-227877): 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 check 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 checked to see 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 incorrect stepping 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 is a vehicle driving assistance device comprising: an acceleration suppression degree setting unit for setting an acceleration suppression degree for suppressing the acceleration of the host vehicle; and a driving state control unit for suppressing the target acceleration of the host vehicle based on the acceleration suppression degree set by the acceleration suppression degree setting unit. The vehicle driving assistance device further comprises: a map information storage unit for storing road map information; a host vehicle position estimating unit for estimating the host vehicle position as the current position of the host vehicle; and a cross-road detection unit for matching the host vehicle position map estimated by the host vehicle position estimating unit to the host vehicle position map stored in the map information storage unit. a prohibited driving area setting unit which, when the intersection road is detected by the intersection road detection unit, sets a prohibited driving area on the lane of the intersection road on the road map information and on the opposite side of the host vehicle; and an arrival distance calculation unit which calculates the arrival distance from the host vehicle to the prohibited driving area, wherein the acceleration suppression level setting unit sets the acceleration suppression level to be higher as the arrival distance becomes shorter based on the arrival distance calculated by the arrival distance calculation unit.

[0016] Technical Effects

[0017] According to the present invention, when it is determined that there is an intersection in front of the vehicle, a prohibited driving area is set on the opposite side of the vehicle across the lane of the intersection, and the acceleration suppression degree for suppressing the acceleration of the vehicle is set to become higher as the reaching distance from the vehicle to the prohibited driving area becomes shorter. Therefore, without using an obstacle recognition sensor, it is possible to identify in advance the place where sudden acceleration needs to be suppressed, and appropriately suppress the occurrence of sudden acceleration due to erroneous stepping at that place. BRIEF DESCRIPTION OF THE DRAWINGS

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

[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 3 is a flowchart showing the acceleration suppression control routine.

[0022] Figure 5 This is a conceptual diagram of the acceleration gain table.

[0023] Figure 6 This is a characteristic diagram showing the relationship between the accelerator operation amount and the target acceleration limited by the acceleration gain.

[0024] Figure 7 It is an explanatory diagram showing acceleration suppression control when the vehicle goes straight through an intersection.

[0025] Figure 8 It is an explanatory diagram showing acceleration suppression control when turning right at a T-intersection.

[0026] Figure 9 It is an explanatory diagram showing acceleration suppression control when turning left at a T-intersection.

[0027] Figure 10 This is an explanatory diagram showing acceleration suppression control when it is unclear which direction to turn at a T-junction.

[0028] Explanation of symbols

[0029] 1…Driving assistance devices

[0030] 11…Navigation unit

[0031] 12…Map positioning calculation unit

[0032] 12a…Own vehicle position estimation calculation unit

[0033] 12b…Driving route setting calculation unit

[0034] 13…GNSS receiver

[0035] 14…Autonomous sensors

[0036] 15…Route information input device

[0037] 16…Road map database

[0038] 21…Camera unit

[0039] 21a…Main camera

[0040] 21b…Secondary camera

[0041] 21c…Image Processing Unit (IPU)

[0042] 21d…Front driving environment recognition unit

[0043] 31…Driving control unit

[0044] 32…Accelerator opening sensor

[0045] 33…Brake switch

[0046] 34…Vehicle speed sensor

[0047] 35…Steering angle sensor

[0048] 36…Turn indicator switch

[0049] 37…Brake drive unit

[0050] 38…Acceleration and deceleration drive unit

[0051] 39…Notification device

[0052] 41…Drive source

[0053] Al…No left turn zone

[0054] Ar…No right turn zone

[0055] ALINE…Starting line

[0056] F…Acceleration suppression control release flag

[0057] Ka…acceleration gain

[0058] Li…reaching distance

[0059] Lia…Limit value

[0060] Lo…Left and right turn determination distance

[0061] M…this vehicle

[0062] Pac1…Acceleration operation threshold

[0063] Pacc…Acceleration operation volume

[0064] S…speed

[0065] WLANE…Lane Width

[0066] α…target acceleration

[0067] αbs…Basic target acceleration DETAILED DESCRIPTION

[0068] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Figure 1 The symbol 1 is a driving assistance device, which is mounted on the vehicle M (refer to Figures 7 to 10 The driving assistance device 1 includes a navigation unit 11 , a camera unit 21 , and a driving control unit 31 .

[0069] 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 pre-stores programs executed by the CPU, data tables, maps, and other fixed data.

[0070] 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.

[0071] 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).

[0072] Specifically, the route information input device 15 is a touch panel of a monitor provided 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 method.

[0073] 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 .

[0074] When a destination and a stopover are input, the map positioning calculation unit 12 sets their position coordinates (latitude and longitude). 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 stopover).

[0075] 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).

[0076] 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.

[0077] 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.

[0078] 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 received position information (latitude and longitude) of the destination (and intermediate point). The driving route setting calculation unit 12b then constructs a driving route connecting the vehicle position and the destination (or, if an intermediate point has been set, the destination via the intermediate point) on the road map information in accordance with pre-set route conditions (such as a recommended route and a fastest route).

[0079] The camera unit 21 includes an onboard camera (stereo camera) consisting of a main camera 21a and a sub-camera 21b fixed to the upper center of the front interior of the vehicle M and 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 with the main camera 21a and captures comparison image data with the sub-camera 21b.

[0080] 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.

[0081] 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.

[0082] This forward driving environment information is read by a driving control unit 31. Connected to the input side of the driving control unit 31 are the forward driving environment recognition unit 21d of the camera unit 21 and the map positioning calculation unit 12. Also connected to this input side are an accelerator opening sensor 32, which detects the accelerator pedal depression amount (accelerator operation amount) Pacc[deg], as an accelerator operation amount detection unit; 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.

[0083] 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 Pacc; and a notification device 39 such as a monitor 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.

[0084] 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.

[0085] 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.

[0086] 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 the figure is used for processing. It should be noted that the following description uses a road that stipulates left-hand traffic as an example. Therefore, on a road that stipulates right-hand traffic, the left side is changed to the right side, and right turns are changed to left turns, and left turns are changed to right turns.

[0087] In this program, first, in step S1, the forward driving environment information identified by the forward driving environment identification unit 21d of the camera unit 21 is read. The program then proceeds to step S2 to check whether there is a potential collision obstacle ahead. If no potential collision obstacle is identified, the program proceeds to step S3. If a potential collision obstacle is identified, the program branches to step S4. If the program branches to step S4, collision avoidance control based on known vehicle integrated control is executed by the braking driver 37 and the acceleration / deceleration driver 38 to avoid collision with the obstacle, and the program then exits.

[0088] 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 S27, described later, and cleared in step S28. If F = 1, the process branches to step S5, where the acceleration gain Ka is set to 100% and the process jumps to step S20. This acceleration gain Ka is a gain that suppresses the target acceleration α set in accordance with the driver's accelerator pedal depression amount (accelerator operation amount Pacc). If Ka = 100%, the normal target acceleration α is set for the accelerator operation amount Pacc.

[0089] On the other hand, if F = 0, the process proceeds to step S6 to execute acceleration suppression control. In step S6, the vehicle position information estimated by the vehicle position estimation calculation unit 12a of the map positioning calculation unit 12 is read. In step S7, 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.

[0090] Then, the process proceeds to step S8, where a check is made based on the road map information to see if there is an intersecting road. Here, the distance ahead of the vehicle's position refers to the normal distance at which the driver considers turning on the turn signal switch 36 to make a left or right turn, for example, within 30 to 20 [m], but not limited thereto. In addition, an intersecting road refers to another road connected to the road on which the vehicle M is traveling, such as a road in which the vehicle M is traveling. Figure 7 The intersection shown and Figure 8 The other road at the T-junction shown is a representative example. Further, the road connected to the parking lot is also included in the intersecting roads.

[0091] If it is determined in step S8 that an intersecting road exists, the process proceeds to step S9. If no intersecting road is detected, the process exits. It should be noted that the processes in steps S7, S8, and step S11 described later correspond to the intersecting road detection unit of the present invention.

[0092] If the process proceeds to step S9, it is checked whether the turn signal switch 36 has been operated. If the turn signal switch 36 has been operated (turned on), the process proceeds to step S10. If the turn signal switch 36 has not been operated (turned off), the process branches to step S11. If the process branches to step S11, based on the aforementioned road map information, it is checked whether there is a straight road ahead of the intersecting road that is continuous with the driving lane of the host vehicle M.

[0093] Then, in straight road discontinuities, e.g. Figure 8 In the case of a T-junction as shown in FIG. 1 , the process proceeds to step S16 . That is, in this case, it is determined that the driver is about to turn the host vehicle M right or left without turning on the turn signal switch.

[0094] On the other hand, in determining Figure 7 If the straight road continues, as shown at the intersection, the driver continues to drive straight because they have kept their accelerator pedal depressed. Therefore, it is assumed that the brake and accelerator pedals have not been accidentally depressed. Furthermore, since the vehicle is driving straight, even if the brake and accelerator pedals were accidentally depressed, it is assumed that the vehicle would not immediately deviate from its lane. Therefore, if the straight road continues, the program is exited.

[0095] Furthermore, when the process proceeds to step S10, it is checked whether the right turn indicator light or the left turn indicator light is on to predict whether the vehicle M is turning right or left. The processing in steps S9 and S10 corresponds to the left and right turn prediction unit of the present invention.

[0096] It is also possible to determine whether the driving lane crosses the intersecting road and connects to the straight road based on the forward driving environment information acquired by the camera unit 21. However, if the vehicle M is in front of an intersection due to dense fog, rain, snow, or other conditions that prevent sufficient visibility, it is not possible to clearly determine whether the straight road is continuous.

[0097] In addition, even if the field of view is ensured, in e.g. Figure 8 At the T-junction shown, if there is no obstacle such as a guardrail in front of the intersecting road, the front driving environment information acquired 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] As a result, the sudden acceleration caused by the wrong stepping of the brake pedal and the accelerator pedal cannot be fully suppressed in the place where it is originally needed. Figure 7 As shown at the intersection, the driving lane of the host vehicle M crosses the intersecting road and continues to go straight.

[0099] If the right turn signal is on, a right turn is predicted, and the process proceeds to step S12. If the left turn signal is on, a left turn is predicted, and the process branches to step S13. If the process proceeds to step S12, a right-turn prohibited zone Ar is set, and the process proceeds to step S14. If the process proceeds to step S13, a left-turn prohibited zone A1 is set, and the process proceeds to step S15. It should be noted that the processes in steps S12, S13, and step S16, described later, correspond to the prohibited zone setting unit of the present invention.

[0100] The prohibited driving areas Ar and Al are the following areas: in order to prevent the situation where the brake pedal and the accelerator pedal are mistakenly stepped on when turning the vehicle M right or left, resulting in crossing the intersection and going straight, a non-road area (prohibited driving area) is set on the opposite side of the driving lane of the vehicle M across the lane of the intersection.

[0101] The right-turn prohibited driving area Ar and the left-turn prohibited driving area Al are set on the road map. Figure 8 As shown in FIG, the right turn prohibited driving area Ar is on the shoulder side of the lane where the vehicle M turns right on the intersecting road, and is set with the lane line on the shoulder side as the starting line ALINE toward the far side. Figure 9As shown, the left turn prohibited driving area A1 is set with the center of the intersection road as the above-mentioned starting line ALINE toward the opposite lane side. Figure 8 、 Figure 9 The intersection shown is a road with one lane on one side, but the same applies even if the intersection is a road with two or more lanes on one side. Figure 8 、 Figure 9 WLANE represents the lane width.

[0102] Specifically, when the vehicle M is about to turn right or left from the lane it is currently traveling in (the driving lane) toward an intersecting road, the driver first releases the accelerator pedal and then decelerates by pressing the brake pedal. The driver then turns the vehicle M right or left by steering while adjusting the speed. After changing the direction of travel to the intersecting road, the driver presses the accelerator pedal to gradually accelerate.

[0103] Therefore, the driver may mistakenly step on the brake pedal and the accelerator pedal during the braking operation just before the vehicle enters an intersection. If the driver mistakenly steps on the accelerator pedal instead of the brake pedal, the vehicle M may cross the intersection and rush forward.

[0104] Therefore, when turning right, the area extending from the shoulder lane marking of the right-turn lane of the intersecting road is set as the right-turn prohibited zone Ar, a non-road area. Furthermore, when turning left, the area extending from the center lane marking of the intersecting road is set as the left-turn prohibited zone A1, a non-road area. Then, when the process proceeds from step S12 to step S14, the arrival distance Li from the vehicle's position to the starting line ALINE of the right-turn prohibited zone Ar is calculated, and the process proceeds to step S19. Furthermore, when the process proceeds from step S13 to step S15, the arrival distance Li from the vehicle's position to the starting line ALINE of the left-turn prohibited zone A1 is calculated, and the process proceeds to step S19. This arrival distance Li is set based on, for example, the position data of the starting line ALINE of the right-turn prohibited zone Ar or the starting line ALINE of the left-turn prohibited zone A1 stored in the road map information, as well as the position data of the vehicle M mapped onto the road map. It should be noted that the processes in steps S14, S15, and step S17 described later correspond to the arrival distance calculation unit of the present invention.

[0105] For example, when a traffic light is set at a T-junction and the traffic light on the driving lane side is green, the driver slowly enters the crossroads. However, at this time, due to the situation of turning right and turning left, for example, Figure 8 、 Figure 9On the single-lane road shown, the right turn is farther than the left turn by the lane width WLANE, so the time to start deceleration is different. Therefore, the arrival distance Li is set based on the starting line ALINE of the prohibited driving area Ar and Al.

[0106] On the other hand, if the process proceeds from step S11 to step S16, the right-turn prohibited driving area Ar is set and the process proceeds to step S17 to calculate the distance Li to the starting line ALINE of the right-turn prohibited driving area Ar. Figure 10 As shown, for example, when a driver of a vehicle M enters a T-junction intersection, even if the turn signal indicator is not illuminated, the driver may turn right or left and drive on the intersecting road. In this case, if a left-turn prohibited area A1 is set, the driver's acceleration will be suppressed more than necessary when the vehicle M is about to turn right, causing discomfort to the driver. Therefore, when the turn signal indicator is not illuminated, the arrival distance Li is set based on the starting line ALINE of the distant right-turn prohibited area Ar.

[0107] Next, the process proceeds from step S17 to step S18, where the arrival distance Li is compared with a preset left / right turn determination distance Lo. This left / right turn determination distance Lo is the distance at which the driver turns left / right during normal driving, and is, for example, approximately 20 to 30 meters. If Li > Lo, the process exits. Otherwise, if Li ≤ Lo, the process proceeds to step S19.

[0108] When the process proceeds to step S19 from any of steps S14, S15, and S17, an acceleration gain Ka serving as the degree of acceleration suppression is determined based on the arrival distance Li by table search or calculation. Figure 5 The concept of the acceleration gain table is shown in Figure 1. As shown in this figure, the value of the acceleration gain Ka is set to decrease as the arrival distance Li decreases, that is, the degree of acceleration suppression is set to a higher value. Furthermore, the limit value Lia for close range is approximately 5 to 10 m, and the limit value Lia for far range is approximately 20 to 30 m. It should be noted that the processing in step S19 corresponds to the acceleration suppression degree setting unit of the present invention.

[0109] Then, when the process proceeds from step S5 or step S19 to step S20, the vehicle speed S (km / h) detected by the vehicle speed sensor 34 and the accelerator operation amount Pacc (deg) detected by the accelerator opening sensor 32 are read. The process then proceeds to step S21, where the accelerator operation amount Pacc is compared with the accelerator operation amount threshold value Pac1. This accelerator operation amount threshold value Pac1 is the value at which the accelerator release is detected, and is approximately Pac1 = 0 to 5 degrees.

[0110] If the accelerator operation amount Pacc is greater than the accelerator operation amount threshold value Pac1 (Pacc>Pac1), the process proceeds to step S22. If the accelerator operation amount Pacc is less than the accelerator operation amount threshold value Pac1 (Pacc≤Pac1), the process branches to step S23.

[0111] Furthermore, in step S22, a basic target acceleration αbs is set based on the vehicle speed S and the accelerator operation amount Pacc, with reference to a basic target acceleration map (not shown). In this basic target acceleration map, a larger basic target acceleration αbs is set as the accelerator operation amount Pacc increases and the vehicle speed S decreases. Next, the process proceeds to step S24, where the acceleration gain Ka is multiplied by the basic target acceleration αbs to set the target acceleration α (α←Ka×αbs).

[0112] Then, the program proceeds to step S25, where the driving torque corresponding to the target acceleration α is calculated. In step S26, a driving signal corresponding to the driving torque is output to the acceleration / deceleration driving unit 38, and the program exits. The acceleration / deceleration driving unit 38 drives the driving source 41 with the driving force corresponding to the driving signal, thereby causing the vehicle M to travel.

[0113] The results, such as Figure 6 As shown, for example, for the acceleration operation amount Pacc when the driver steps on the accelerator pedal from a stopped state (vehicle speed = 0 [Km / h]), since the acceleration gain Ka is set to a value that becomes smaller as the arrival distance Li becomes shorter, the target acceleration α is set to a value that is gradually suppressed more strongly.

[0114] Therefore, when the host vehicle M approaches an intersection or enters a main road from a parking lot, even if the accelerator pedal is mistakenly pressed hard as the brake pedal, the target acceleration α is suppressed, thereby preventing sudden acceleration.

[0115] On the other hand, if the process branches from step S21 to step S23, the value of the acceleration suppression control release flag F is checked. If F = 0, it is determined that acceleration suppression control was in effect until the last calculation, and the process proceeds to step S27, where the acceleration suppression control release flag F is set (F←1). After acceleration suppression control is released, the process exits. On the other hand, if F = 1, it is determined that acceleration suppression control was in effect until the last calculation, and the process branches to step S28, where the acceleration suppression control release flag F is cleared (F←0). After acceleration suppression control is resumed, the process exits.

[0116] Therefore, if the driver releases the accelerator pedal during the acceleration suppression control, the acceleration suppression control release flag F is set (F←1) in step S27, and the acceleration gain Ka is set to 100[%] in step S5. As a result, if the driver depresses the accelerator pedal again after releasing the accelerator pedal, which is the so-called second depressing, it is determined that the driver has intentionally depressed the accelerator pedal, and the normal target acceleration (equivalent to 100%) corresponding to the driver's accelerator pedal operation amount is set. Figure 6 (Ka=100[%]). It should be noted that the processing in step S21, step S23, and step S27 corresponds to the acceleration suppression control release detection unit of the present invention.

[0117] 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 checked whether there is a straight road that is continuous with the lane in front of the intersection road. If the straight road is not continuous, acceleration suppression control is performed. Therefore, it is possible to identify in advance the place where sudden acceleration needs to be suppressed without using the camera unit 21 (obstacle recognition sensor), and to appropriately suppress the occurrence of sudden acceleration caused by incorrect stepping at that place.

[0118] Furthermore, since the acceleration suppression control is configured to gradually increase as the distance Li from the host vehicle M to the starting line ALINE of the prohibited travel areas Ar and Al decreases, it is possible to reliably detect a driver's erroneous accelerator pedaling. Furthermore, if the accelerator pedal is depressed a second time, it is determined to be an acceleration request in accordance with the driver's intention, and the acceleration suppression control is released, thereby enabling control that is more in line with the driver's intention.

[0119] It should be noted that the present invention is not limited to the above-mentioned embodiments, and can also be applied, for example, when the driving mode in an autonomous vehicle is changed 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 setting unit that sets 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 set by the acceleration suppression degree setting unit, The vehicle driving assistance device further includes: a map information storage unit for storing road map information; a vehicle position estimating unit for estimating a vehicle position as a current position of the vehicle; an intersecting road detecting unit that matches the vehicle position map estimated by the vehicle position estimating unit to the road map information stored in the map information storage unit to detect whether there is an intersecting road ahead of the vehicle; a prohibited travel area setting unit configured to set a prohibited travel area when the intersecting road is detected by the intersecting road detecting unit; as well as an arrival distance calculation unit for calculating an arrival distance from the host vehicle to the prohibited travel area, On a road designated for left-hand traffic, when the driver turns right with respect to the intersecting road, an area extending from the lane marking on the shoulder of the right-turn lane of the intersecting road toward the distance is set as the prohibited driving area; and when the driver turns left with respect to the intersecting road, an area extending from the lane marking in the center of the intersecting road toward the distance is set as the prohibited driving area. On a road designated as right-hand traffic, when the driver turns left with respect to the intersecting road, an area extending from the lane marking on the shoulder of the left-turn lane of the intersecting road toward the distance is set as the prohibited driving area; and when the driver turns right with respect to the intersecting road, an area extending from the lane marking in the center of the intersecting road toward the distance is set as the prohibited driving area. The acceleration suppression degree setting unit sets the acceleration suppression degree to be higher as the arrival distance becomes shorter, based on the arrival distance calculated by the arrival distance calculation unit.

2. The vehicle driving assistance device according to claim 1, wherein: On a road designated for left-hand traffic, when the driver turns the host vehicle right with respect to the intersecting road, the starting line is set at the lane marking on the shoulder side of the right-turn lane of the intersecting road; and when the driver turns the host vehicle left with respect to the intersecting road, the starting line is set at the center of the intersecting road. On a road designated as right-hand traffic, when the driver turns the host vehicle left with respect to the intersecting road, the starting line is set at the lane marking on the shoulder side of the left-turn lane of the intersecting road; and when the driver turns the host vehicle right with respect to the intersecting road, the starting line is set at the center of the intersecting road. The arrival distance calculation unit obtains the distance from the vehicle position to the start line of the prohibited travel area as the arrival distance.

3. The vehicle driving assistance device according to claim 2, wherein: The vehicle driving assistance device further includes a left-right turn prediction unit configured to predict whether the vehicle will turn right or left with respect to the intersecting road. The right or left turn prediction unit predicts whether the host vehicle will turn right or left based on the operation of a turn signal switch by the driver.

4. The vehicle driving assistance device according to claim 3, wherein: The prohibited travel area setting unit does not set the prohibited travel area when the turn signal switch is not operated and it is determined based on the road map information stored in the map information storage unit that a straight road that continues in the traveling direction of the vehicle is provided ahead of the intersecting road.

5. The vehicle driving assistance device according to claim 3, wherein: When the turn signal switch is not operated and it is determined based on the road map information stored in the map information storage unit that there is no straight road continuous in the direction of travel of the vehicle in front of the intersection road, the prohibited driving area setting unit sets the starting line of the prohibited driving area on the lane line on the shoulder side of the road on the opposite side of the intersection road from the position of the vehicle.

6. The vehicle driving assistance device according to any one of claims 1 to 5, characterized in that: The vehicle is an autonomous driving vehicle. When the driving mode of the autonomous driving 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 setting unit sets the acceleration suppression degree. The traveling state control unit suppresses acceleration of the host vehicle based on the acceleration suppression degree set by the acceleration suppression degree setting unit.

7. The vehicle driving assistance device according to claim 1, wherein: The vehicle driving assistance device further comprises: an accelerator operation amount detecting portion 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 with respect to the target acceleration when the acceleration suppression control cancellation detection unit detects release of the accelerator pedal.

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