JP2016084093A - Traveling control system of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure safety by guiding a vehicle to an evacuation point along an appropriate route in the course of autonomous driving control even when an abnormality occurs in a steering system under a situation that traveling environment information cannot be acquired.SOLUTION: During autonomous driving control, when an abnormality occurs during acquisition of traveling environment information necessary to perform autonomous driving and an abnormality is detected in a steering system of an own vehicle, a traveling mode designation unit 11 of a traveling control system 10 designates an evacuation route, along which safety of the own vehicle is ensured, on the basis of the traveling environment information acquired last before the abnormality is detected during acquisition of the traveling environment information, and designates a traveling mode, in which the own vehicle is advanced along the evacuation route, according to a situation in which the abnormality has occurred. An evacuation traveling control unit 12 of the traveling control system 10 decelerates the own vehicle according to the traveling mode, and controls a yaw moment via a brake control unit 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle travel control system that recognizes a travel environment, detects travel information of a host vehicle, and performs automatic driving control.

  In recent years, various types of vehicles using automatic driving technology have been developed and proposed so that drivers can drive more comfortably and safely. For example, in Japanese Patent Application Laid-Open No. 2003-63373 (hereinafter referred to as Patent Document 1), when a failure occurs in the steering system, the braking force applied to the left and right wheels is controlled to change the course of the vehicle so as to obtain a predetermined retreat area. There is disclosed a technology of a vehicle automatic retracting device for stopping a vehicle inside.

JP 2003-63373 A

  In the technology of the vehicle automatic evacuation device disclosed in Patent Document 1 described above, a plurality of evacuation area candidates are always obtained, and when a failure occurs in the steering system, the evacuation area is set. Based on this positional relationship, the vehicle is decelerated and yaw brake control for adding a yaw moment to the vehicle is executed.

  However, if the driving environment information cannot be obtained due to some abnormality (for example, abnormalities in detection equipment such as a camera / radar, bad weather, etc.) (including a decrease in detection accuracy), the evacuation area and the traveling vehicle It becomes difficult to obtain the positional relationship, the vehicle cannot be retreated to the retreat area, and the safety of the vehicle may not be ensured.

  The present invention has been made in view of the above circumstances, and in automatic driving control, even if an abnormality occurs in the steering system under a situation where traveling environment information cannot be obtained, the vehicle is retracted along an appropriate route. It is an object of the present invention to provide a vehicle travel control system that can be guided to the vehicle to ensure safety.

  A vehicle travel control system according to an aspect of the present invention is a vehicle travel control system that performs automatic operation control based on travel environment information of an environment in which the host vehicle travels and travel information of the host vehicle. In this case, if an abnormality is detected in the acquisition of the travel environment information and an abnormality is detected in the steering system of the host vehicle, the travel acquired last before the abnormality is detected in the acquisition of the travel environment information A travel mode setting unit that sets a retreat route for ensuring the safety of the host vehicle based on environmental information, and sets a travel mode that travels along the retreat route according to a situation when an abnormality occurs, and the travel mode And a retreat travel control unit that controls deceleration and yaw moment of the host vehicle via brake control.

  According to the present invention, in automatic driving control, even if an abnormality occurs in the steering system in a situation where traveling environment information cannot be obtained, the vehicle is guided to the evacuation point by an appropriate route to ensure safety. It becomes possible to do.

Overall configuration diagram of a vehicle travel control system Explanatory drawing showing an example of retreat travel control Illustration of the yaw rate that changes depending on the steering wheel holding state Explanatory diagram showing selection conditions for travel mode Flow chart of emergency evacuation control during automatic operation control Flowchart of abnormal evacuation control during automatic operation control (continued) Explanatory drawing which shows the vehicle speed and additional yaw moment adjustment gain by driving modes M1, M2, M5 and M6 Explanatory drawing which shows the vehicle speed and additional yaw moment adjustment gain by driving modes M3, M4, M7 and M8

  Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the code | symbol 1 has shown the traveling control system of the vehicle comprised centering on the traveling control apparatus 10. FIG. The travel control device 10 includes a surrounding environment recognition device 15, an own vehicle position information detection device 16, an inter-vehicle communication device 17, a road traffic information communication device 18, an engine control device 20, a brake control device 21, a steering control device 22, an alarm. The device 23 and the like are connected via a communication bus 100 forming an in-vehicle network, and a switch group 19 for various settings and operations is connected.

  The surrounding environment recognition device 15 is a camera device (stereo camera, monocular camera, color camera, etc .: not shown) provided with a solid-state imaging device or the like provided in a vehicle interior that captures image information by photographing the external environment of the vehicle. A radar apparatus (laser radar, millimeter wave radar, ultrasonic radar, etc .: not shown) that receives a reflected wave from a three-dimensional object existing around the vehicle.

  The surrounding environment recognition device 15 performs, for example, a well-known grouping process on the distance information based on the image information captured by the camera device, and the three-dimensional road shape in which the grouping distance information is set in advance. By comparing the data, solid object data, etc., the lane line data, guardrails existing along the road, sidewall data such as curbs, three-dimensional object data such as vehicles, etc. are displayed in relative positions (distance, Angle) is extracted along with the velocity.

  The surrounding environment recognition device 15 detects the position (distance, angle) of the reflected three-dimensional object along with the speed based on the reflected wave information acquired by the radar device. In the present embodiment, the maximum distance that can be recognized by the surrounding environment recognition device 15 (the distance to the three-dimensional object, the farthest distance of the lane marking) is used as the visibility. Further, the surrounding environment recognition device 15 outputs the abnormality of the surrounding environment recognition device 15 to the travel control device 10 when the accuracy of the surrounding environment recognition device decreases due to, for example, an abnormality in the camera device, the radar device, or bad weather. To do.

The own vehicle position information detection device 16 is, for example, a known navigation system, and receives, for example, a radio wave transmitted from a GPS (Global Positioning System) satellite and determines the current position based on the radio wave information. Detected on map data stored in advance in flash memory, CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray (Blu-ray) disc, HDD (Hard disk drive), etc. Identify your vehicle position.

  The map data stored in advance includes road data and facility data. Road data includes link position information, type information, node position information, type information, and information on connection relations between nodes and links, that is, road branching, junction point information and maximum vehicle speed information on branch roads, etc. Contains. The facility data has a plurality of records for each facility, and each record includes the name information of the target facility, location information, facility type (department store, store, restaurant, parking lot, park, vehicle failure) It has data that shows information). Then, the vehicle position on the map position is displayed, and when the destination is input by the operator, the route from the departure point to the destination is calculated in advance, and the image display on the display and the voice guidance from the speaker Can be guided by.

  The inter-vehicle communication device 17 is constituted by a wireless communication device having a predetermined communication area, for example, and can communicate with other vehicles to transmit and receive information. And vehicle information, traveling information, traffic environment information, etc. are exchanged by mutual communication with other vehicles. The vehicle information includes unique information indicating the vehicle type (in this embodiment, the type of passenger car, truck, motorcycle, etc.). The traveling information includes vehicle speed, position information, brake lamp lighting information, blinking information of a direction indicator transmitted at the time of turning left and right, and blinking information of a hazard lamp blinking at an emergency stop. Furthermore, the traffic environment information includes information that varies depending on the situation such as road traffic congestion information and construction information.

  The road traffic information communication device 18 is a so-called road traffic information communication system (VICS: Vehicle Information and Communication System: registered trademark). From FM multiplex broadcasting or a transmitter on the road, traffic congestion, accidents, construction, required time, The road traffic information of the parking lot is received in real time, and the received traffic information is displayed on the previously stored map data.

  The switch group 19 is a switch group related to driver's driving support control. For example, the switch group 19 is a switch that controls traveling at a constant speed set in advance, or sets an inter-vehicle distance from the preceding vehicle and an inter-vehicle time in advance. A switch for keeping track at a constant value, a lane keeping control switch for driving control while maintaining the driving lane at the set lane, a lane departure preventing control switch for preventing departure from the driving lane, and preceding Passing control execution permission switch for executing overtaking control of vehicles (vehicles to be overtaken), switch for executing automatic driving control for performing all these controls in cooperation, vehicle speed, inter-vehicle distance, inter-vehicle distance required for each control It consists of a switch for setting time, speed limit, etc., or a switch for canceling each control.

  The engine control device 20 is a well-known control unit that controls the operating state of a vehicle engine (not shown). For example, the intake air amount, throttle opening, engine water temperature, intake air temperature, air-fuel ratio, crank angle, accelerator Based on the opening degree and other vehicle information, main control such as fuel injection control, ignition timing control, and electronic throttle valve opening control is performed.

  The brake control device 21 makes the four-wheel brake device (not shown) independent of the driver's brake operation based on, for example, the brake switch, the wheel speed of the four wheels, the handle angle θH, the yaw rate γ, and other vehicle information. This is a well-known control unit that controls the yaw moment that controls the yaw moment that is added to the vehicle, such as the well-known antilock brake system and the anti-slip control, and the yaw brake control. is there. Then, when the brake force of each wheel is input from the travel control device 10, the brake control device 21 calculates the brake fluid pressure of each wheel based on the brake force, and a brake drive unit (not shown). ).

  The steering control device 22 is, for example, an assist torque by an electric power steering motor (not shown) provided in the vehicle steering system based on the vehicle speed V, the driver steering torque Tdrv, the steering wheel angle θH, the yaw rate γ, and other vehicle information. It is a known control device that controls In addition, the steering control device 22 can perform lane keeping control for performing traveling control while maintaining the above-described traveling lane at the set lane, and lane departure preventing control for performing departure prevention control from the traveling lane. The steering angle or the steering torque necessary for the lane departure prevention control is calculated by the travel control device 10 and input to the steering control device 22, and the electric power steering motor is driven and controlled according to the input control amount. . Further, the steering control device 22 detects abnormalities such as a steering system including a steering mechanism, a steering torque sensor, and a steering angle sensor. The traveling control device 10 monitors the occurrence of these abnormal states. Yes.

  The alarm device 23 is a device that appropriately generates an alarm when abnormality occurs in various devices of the vehicle. For example, a visual output such as a monitor, a display, and an alarm lamp, and an auditory sound such as a speaker and a buzzer are provided. Warning / notification is performed using at least one of the outputs. As will be described later, when retreating when an abnormality occurs, a warning is given not only to the passenger of the host vehicle but also to other vehicles and pedestrians around the host vehicle. Notification.

  The travel control device 10 serving as the center of the travel control system 1 having the above devices is based on input information and control information from the devices 15 to 22 to prevent collision with obstacles, constant speed travel control, Automatic driving control and the like are executed in coordination with follow-up running control, lane keeping control, lane departure prevention control, and other overtaking control. During this automatic driving control, there are abnormalities (for example, stop of image recognition, deterioration of reliability, deterioration of radar wave transmission / reception function, etc.) that cannot normally acquire the travel environment information necessary for automatic driving. When the abnormality occurs in the steering system of the host vehicle, the traveling control device 10 performs retreat traveling control for retracting the host vehicle to a safe position in an appropriate traveling mode according to the situation when the abnormality occurs. .

  For this reason, the travel control device 10 includes a control function mainly including the travel mode setting unit 11 and the retreat travel control unit 12 as functions for retreat travel control. The traveling mode setting unit 11 detects an abnormality in the acquisition of traveling environment information when an abnormality is detected in the acquisition of traveling environment information and an abnormality is detected in the steering system of the host vehicle during automatic driving control. Based on the travel environment information acquired at the last time, a retreat route for ensuring the safety of the host vehicle is set, and a travel mode for traveling along the retreat route is set. The retreat travel control unit 12 controls the deceleration and yaw moment of the host vehicle via the brake control device 21 according to the set travel mode.

  Specifically, as shown in FIG. 2, the travel mode setting unit 11 includes a road boundary curb, a stopped vehicle, and the like within the travel environment information acquisition possible range detected last before the acquisition of the travel environment information becomes abnormal. A route to a travel position where the vehicle can stop safely on the road shoulder is set as a retraction route safely without contacting the obstacle. In the example of FIG. 2, if the driving environment information acquisition and the steering system are normal in the left curve, the target route along the road is as shown by the broken line in the figure, but the driving environment information acquisition and the steering system are In the case of an abnormality, an example is shown in which a retreat route toward the vehicle toward the road shoulder inside the curve is set as shown by a solid line.

  In FIG. 2, Lc represents the visibility recognized last. In the example of FIG. 2, no obstacle or the like is shown on the road shoulder, but when there is an obstacle or the like on the shoulder, the retreat path is set to a distance to the front of the obstacle.

Here, assuming that the curvature of the retreat path is κc, the retreat target handle angle θHF necessary for traveling along the path of the curvature κc can be calculated by the following equation (1).
θHF = (1 + A · V ² ) · l · n · κc (1)
A: Stability factor specific to the vehicle
V: Vehicle speed
l: Wheel base
n: Steering gear ratio

In order to safely stop on the road shoulder, the difference (θHF−θH0) between the target steering wheel angle θHF at the time of retraction and the steering wheel angle θH0 when the traveling environment information acquisition and steering system is determined to be abnormal is set as a necessary steering wheel angle θH_vdc, The yaw moment corresponding to the necessary handle angle θH_vdc is generated by the yaw brake control via the brake control device 21 and added to the vehicle. This additional yaw moment Mzt can be calculated by the following equation (2), for example.
Mzt = Kbm · (2 · Kf · Kr) / (Kf + Kr) · (θH_vdc / n) (2)
Kf: equivalent cornering power of the front wheels
Kr: Equivalent cornering power of rear wheel
Kbm: Adjustment gain according to the driving mode

  When θH0 changes due to an abnormality in the steering system, the additional yaw moment Mzt is calculated using the steering wheel angle θH detected every moment, that is, θH_vdc = θHF−θH.

  In this case, since the additional yaw moment Mzt is generated by the yaw brake control, there is a possibility that sufficient cornering power cannot be obtained in the low vehicle speed range, and the yaw moment necessary for approaching the road shoulder cannot be obtained. In addition, when the vehicle speed becomes low, it is possible to maintain the curvature along the set route by generating a yaw rate according to the traveling path and the vehicle speed when the driver operates or holds the steering wheel. However, when the steering wheel is not held, self-steering in the turning direction occurs, and the yaw rate by the yaw brake control becomes excessive, making it difficult to maintain the curvature.

Here, the vehicle motion when the driver operates / fixes the steering wheel is given by the following equations (3) and (4). From these equations (3) and (4), the yaw rate γ is It is obtained by the following equation (5).
2 · (Kf + Kr) · β + (m · V + (2 / V) · (lf · Kf−lr · Kr)) · γ = 2 · Kf · δ (3)
2 · (lf · Kf−lr · Kr) · β + (2 · (lf ² · Kf + lr ² · Kr) / V) · γ = 2 · lf · Kf · δ + Mz (4)
γ = (1 / (1 + A · V ² )) · (V / l) · (δ + (Kf + Kr) / (2 · l · Kf · Kr)) · Mz) (5)
Where m: vehicle mass
β: Body slip angle
δ: Front wheel rudder angle
lf: Distance between front axis and center of gravity
l: Distance between rear axis and center of gravity
Mz: Additional yaw moment

On the other hand, when the driver releases his / her hand from the steering wheel, the front wheels freely steer according to the self-aligning torque and no lateral force is generated. Therefore, the vehicle motion at this time is given by the following formulas (6) and (7) with Kf in the formulas (3) and (4) set to 0, and from the formulas (6) and (7): The yaw rate γ is obtained by the following equation (8).
2 · Kr · β + (m · V− (2 / V) · lr · Kr) · γ = 0 (6)
-2 · lr · Kr · β + ((2 · lr ² · Kr) / V) · γ = Mz (7)
γ = Mz / (m · lr · V) (8)

  An example of the yaw rate γ obtained from the equations (5) and (8) is shown in FIG. When the driver operates / fixes the steering wheel, the characteristic of the yaw rate γ is as shown by the solid line in FIG. 3, and a yaw rate close to a constant turning radius is added by the yaw brake control. On the other hand, when the driver releases his / her hand from the steering wheel, the characteristic of the yaw rate γ is as shown by the broken line in FIG. 3, and the yaw moment generated by the braking force is rapidly increased at a low speed by the self-steering in the turning direction.

  That is, as is clear from the equations (5), (8), and FIG. 3, when the yaw moment control of the vehicle is performed by the braking force, the steering angle is fixed for the yaw rate γ generated by the yaw moment control. And the case where the steering angle changes due to the self-alignment torque, it is necessary to control appropriately according to the situation. Furthermore, the collision of the following vehicle by the deceleration of the own vehicle is also assumed.

  For this reason, the traveling mode setting unit 11 sets a traveling mode in which the deceleration and the additional yaw moment of the host vehicle are optimized according to the situation at the time of occurrence of the abnormality, and advances the retreat route in this traveling mode. In the present embodiment, the following (1) to (8) according to the vehicle speed V of the host vehicle when an abnormality occurs, the state of holding / non-holding of the driver's handle, and the distance Lv between the host vehicle and the obstacle. A plurality of travel modes M1 to M8 as shown in FIG.

  In each of the travel modes M1 to M8, a retract path for the curvature κc is set for each mode, and an adjustment gain Kbm for adjusting the additional yaw moment Mzt necessary for tracing the path for the curvature κc is set for each mode. In addition, the target deceleration Gmd is determined for each mode so that the host vehicle is stopped on the road shoulder or brought close to the road shoulder within the maximum visibility range.

  Then, as shown in FIG. 4, from among these travel modes M1 to M8, a condition as to whether the vehicle speed V of the host vehicle is equal to or higher than a threshold Vh, a distance Lv between an obstacle present around the host vehicle and the host vehicle. The driving mode depends on whether or not the vehicle is far away from the threshold Lh and whether the driver holds the handle (| Tdrv | ≧ Tdrvc: Tdrvc is a set value) or not (| Tdrv | <Tdrvc) And set as the optimal driving mode according to the situation at the time of occurrence of abnormality.

  Here, the travel modes M1 to M4 are travel modes when the vehicle speed at the time of failure is on the high speed side, and the travel modes M5 to M8 are travel modes when the vehicle speed at the time of failure is on the low speed side. Is a vehicle speed threshold at which a sufficient yaw moment is generated by the yaw brake control. The distance threshold Lh is a threshold for giving priority to the deceleration for avoiding the collision over the addition of the yaw moment when a collision with an obstacle is predicted such as when the preceding vehicle suddenly decelerates. These threshold values are obtained in advance by experiments or simulations for each vehicle type, and are stored in a memory as control constants in the system.

(1) Travel mode M1
This mode is selected under the condition of V ≧ Vh (high vehicle speed), Lv ≧ Lh (obstacle is far away) and holding the steering wheel, and is a mode with a low risk of collision with the obstacle. In the traveling mode M1, the host vehicle is decelerated while being brought close to the road shoulder immediately via control.

(2) Travel mode M2
The driving mode M2 is a mode selected under the condition of V ≧ Vh (high vehicle speed), Lv ≧ Lh (obstacle is far away), and the handle non-holding, and like the driving mode M1, there is a risk of collision with an obstacle. Although it is a low mode, since the driver does not hold the handle, yaw control becomes difficult in the second half of the control. For this reason, in the traveling mode M2, first, the control to approach the road shoulder is performed, and after approaching the road shoulder, deceleration is started.

(3) Travel mode M3
The driving mode M3 is a mode selected under the condition of V ≧ Vh (high vehicle speed) and Lv <Lh (obstacle is near) and holding the steering wheel, and is close to the obstacle and has high collision risk. It is. In the traveling mode M3, the speed is adjusted according to the obstacles before and after the host vehicle, and after the safety is confirmed, the vehicle is decelerated while approaching the road shoulder. As with the travel mode M3, the travel modes M4, M7, and M8 are modes that have a high risk of collision with an obstacle. If safety is not ensured within the maximum visibility range, the travel modes are approached. Gradually weaken control.

(4) Travel mode M4
The travel mode M4 is a mode selected under the conditions of V ≧ Vh (high vehicle speed), Lv <Lh (obstacle is near), and no handle is held. The travel mode M4 is a mode in which the risk of collision with an obstacle is high as in the travel mode M3. However, since the driver does not hold the steering wheel, yaw control becomes difficult in the second half of the control. For this reason, in the traveling mode M4, the speed is adjusted according to the obstacles before and after the host vehicle, control is performed to approach the road shoulder after safety is confirmed, and deceleration is started after approaching the road shoulder.

(5) Travel mode M5
The traveling mode M5 is a mode selected under the conditions of V <Vh (low vehicle speed), Lv ≧ Lh (obstacle is far away), and handle holding. Since the driving mode M5 is a mode in which the risk of collision with an obstacle is low as in the driving modes M1 and M2, the control is immediately started. However, the driving mode M5 is sufficiently close to the road shoulder as compared with the driving modes M1 and M2. There is a possibility that there is no possibility, but control as close to the shoulder as possible is performed.

(6) Travel mode M6
The travel mode M6 is a mode selected under the conditions of V <Vh (low vehicle speed), Lv ≧ Lh (obstacle is far away), and the handle non-holding. The driving mode M6 differs from the driving mode M5 only in the condition of not holding the steering wheel, and the driver does not hold the steering wheel. Make it smaller.

(7) Travel mode M7
The travel mode M7 is a mode selected under the conditions of V <Vh (low vehicle speed), Lv <Lh (obstacle is near), and holding the steering wheel. Like the travel modes M3 and M4, the collision risk with the obstacle Since this is a mode with high performance, the speed is adjusted according to the obstacles before and after the host vehicle, and after the safety is confirmed, control is performed to approach the road shoulder. The travel mode M7 is a control in a lower speed region than the travel modes M3 and M4, and therefore may not be sufficiently close to the road shoulder. However, the travel mode M7 is controlled as close to the road shoulder as possible.

(8) Travel mode M8
The travel mode M8 is a mode that is selected under the condition of V <Vh (low vehicle speed), Lv <Lh (obstacle is near), and the non-holding of the steering wheel, and is similar to the travel modes M3, M4, and M7. This mode has a high risk of collision. The travel mode M8 is a mode in which the driver does not hold the steering wheel with respect to the travel mode M7. Therefore, in order to suppress an excessive generation of the yaw rate in the second half of the control, the additional yaw moment is made smaller than that in the travel mode M7. .

In order to give the deceleration and yaw moment in each of the above row modes, the retreat travel control unit 12 applies the braking force of each wheel (braking force Ffi of the turning inner front wheel, braking force Ffo of the turning outer front wheel, braking force of the turning inner rear wheel) Fri, braking force Fro of the rear outer wheel of the turn) is calculated by, for example, the following formulas (9) to (12), and the calculated value of the braking force is output to the brake control device 21.
Ffi = (Kx / 2) · Fx + Ky · Fy (9)
Ffo = (Kx / 2) · Fx−Ky · Fy (10)
Fri = ((1-Kx) / 2) .Fx + (1-Ky) .Fy (11)
Fro = ((1-Kx) / 2) .Fx- (1-Ky) .Fy (12)

Here, Kx is the front / rear braking force distribution ratio (front wheel side braking force / total braking force) of deceleration control, and Fx is the total braking force, and is set to the target deceleration Gmd during retraction set for each travel mode. Based on the following equation (13).
Fx = −m · Gmd · t (13)

Also, ky is the front-rear axis distribution ratio (front yaw moment / total yaw moment) of yaw moment control, Fy is the sum Fy of the left and right wheel brake force differences according to the additional yaw moment Mzt, and the tread is d. It is calculated by the following equation (14).
Fy = Mzt / d (14)

  In addition, when the retreat control is executed, the retreat travel control unit 12 outputs an instruction value for the brake force of each wheel to the brake control device 21 and instructs the alarm device 23 to output a warning so that an occupant of the own vehicle is abnormal. In addition to notifying the evacuation, other vehicles and pedestrians in the vicinity of the host vehicle are informed by the brake lamp and the hazard lamp that the vehicle is evacuating when an abnormality occurs. The notification during the evacuation travel is not limited to visual notification by a brake lamp or a hazard lamp, but may be transmitted to another vehicle by inter-vehicle communication.

  Next, the program processing of the evacuation travel control by the travel modes M1 to M8 executed by the travel control device 10 will be described using the flowcharts shown in FIGS.

  In the retreat travel control, first, in the first step S101, it is determined whether or not the automatic operation state in which the automatic operation control is being executed. If it is not in the automatic driving state, the program is exited. If it is in the automatic driving state, the process proceeds to S102, and there is an abnormality in obtaining the driving environment information necessary for performing the automatic driving (for example, stop of image recognition, deterioration of reliability, radar It is determined whether or not a wave transmission / reception function is degraded.

  As a result of the determination in step S102, if the travel environment information acquisition is normal, the program exits, and if an abnormality has occurred in the travel environment information acquisition, the process proceeds to step S103. Proceeding to step S103, it is determined whether or not an abnormality in the steering system is detected. If no abnormality in the steering system is detected, the program exits, and if an abnormality in the steering system is detected, step S104 is performed. Proceed to

  In step S104, it is determined whether or not the vehicle speed V at the time of failure is equal to or higher than the threshold value Vh. If V ≧ Vh, the process proceeds to step S105, and if V <Vh, the process proceeds to step S112. Steps S112 and after are processes related to the travel modes M5 to M8, and steps S105 to S111 are processes related to the travel modes M1 to M4.

  First, the processing of steps S105 to S111 will be described. In step S105, it is determined whether or not the distance Lv between the host vehicle and the obstacle is greater than or equal to a threshold value Lh. If Lv <Lh, the driver holds the steering wheel in step S106 (| Tdrv | ≧ Tdrvc) or not. It is determined whether it is holding (| Tdrv | <Tdrvc). If the driver holds the steering wheel, the process proceeds to step S107 to perform the retreat traveling in the driving mode M1. If the driver does not hold the steering wheel, the process proceeds to step S108 and the driving mode M2 is retreated. Run.

  As shown in FIG. 7, when the retreat path is expressed by two-dimensional coordinates in which the front-rear direction of the host vehicle is the x direction and the lateral direction is the y direction), there is a risk of collision with an obstacle in retreat travel in the travel mode M1. Is low, immediately decelerate the vehicle to the shoulder and stop. On the other hand, in the retreat travel in the travel mode M2, the driver does not hold the steering wheel. Therefore, as shown in FIG. 7, in the first half of the control, the yaw moment control approaching the road shoulder is given priority over the road shoulder, and the vehicle approaches the road shoulder. Deceleration is started in the latter half of the later control, and the vehicle is stopped at the retreat position near the maximum visibility distance.

  The traveling mode M1 and the traveling mode M2 have different yaw moment addition and deceleration control timings, and the evacuation path curvature κc and the target deceleration Gmd are set to different values. However, the adjustment gain Kbm of the additional yaw moment Mzt is set to the same value in the travel modes M1 and M2.

  On the other hand, if Lv <Lh in step S105, the process proceeds from step S105 to step S109 to determine whether the driver holds the handle (| Tdrv | ≧ Tdrvc) or not (| Tdrv | <Tdrvc). Determined. If the driver holds the steering wheel, the traveling mode M3 is evacuated in step S110. If the driver does not hold the steering wheel, the traveling mode M4 is evacuated in step S111.

  Since the driving mode M3 has a high risk of collision with an obstacle, as shown in FIG. 8, the speed is adjusted according to the obstacles before and after the host vehicle, and safety is ensured. Start. In this movement to the road shoulder, the vehicle is decelerated while adding a yaw moment, and the vehicle is stopped at the retreat position near the maximum visibility distance.

  On the other hand, in the driving mode M4, similarly, the speed is adjusted according to the obstacles before and after the host vehicle, and then the movement to the road shoulder is started. However, since the driver does not hold the steering wheel, as shown in FIG. In the first half of the control, the yaw moment control approaching the road shoulder is prioritized over the deceleration, the deceleration starts in the second half of the control after approaching the road shoulder, and the vehicle stops at the retreat position near the maximum visibility distance.

  The traveling mode M3 and the traveling mode M4 are the same in that the movement to the road shoulder is started after adjusting the speed according to the front and rear obstacles, but the curvature κc and the target deceleration Gmd of the retreat path are different. The adjustment gain Kbm of the additional yaw moment Mzt in the traveling mode M3 is set to a value larger than that in the traveling modes M1 and M2. Further, the adjustment gain Kbm of the additional yaw moment Mzt in the traveling mode M4 is set to be larger than that in the traveling mode M3 so as to be brought close to the road shoulder in the first half of the control.

  Next, processing related to travel modes M5 to M8 after step S112 will be described. In step S112, it is determined whether or not the distance Lv between the host vehicle and the obstacle is greater than or equal to a threshold value Lh. If Lv <Lh, the driver holds the steering wheel in step S1113 (| Tdrv | ≧ Tdrvc) or not. It is determined whether it is holding (| Tdrv | <Tdrvc). When the driver holds the steering wheel, the process proceeds to step S114 to perform the traveling mode M5, and when the driver does not hold the steering wheel, the process proceeds to step S115 to perform the traveling mode M6. Do.

  The driving modes M5 and M6 are modes in which the risk of collision with an obstacle is low, as in the driving modes M1 and M2, but because the vehicle is in a lower vehicle speed range than the driving modes M1 and M2, the driving modes M5 and M6 cannot be sufficiently approached. there is a possibility. As is apparent from FIG. 7, the curvature κc and the target deceleration Gmd of the retreat path in the travel modes M5 and M6 are the same, and are set with the intention of being able to approach the road shoulder before the start of deceleration in the travel mode M2. . The adjustment gain Kbm of the additional yaw moment Mzt in the traveling modes M5 and M6 is set smaller than that in the traveling modes M1 and M2, and in the traveling mode M6 when the driver does not hold the steering wheel, the adjustment gain Kbm In order to suppress an excessive generation of the yaw rate, the adjustment gain Kbm is set smaller than that in the travel mode M5.

  On the other hand, if Lv <Lh in step S112, the process proceeds from step S112 to step S116 to determine whether the driver holds the handle (| Tdrv | ≧ Tdrvc) or not (| Tdrv | <Tdrvc). Determined. If the driver holds the steering wheel, the traveling mode M7 is evacuated in step S117. If the driver does not hold the steering wheel, the traveling mode M8 is evacuated in step S1118.

  Travel modes M7 and M8 are modes in which the risk of collision with obstacles is low, similar to travel modes M3 and M4, and after moving to the shoulder after adjusting the speed according to the front and rear obstacles, Since the vehicle speed range is lower than that in modes M3 and M4, there is a possibility that the vehicle cannot be fully approached. For this reason, in the travel modes M7 and M8, the curvature κc and the target deceleration Gmd of the retreat route up to the maximum visibility distance are set so as to be as close to the road shoulder as possible after the movement to the road shoulder is started.

  The adjustment gain Kbm of the additional yaw moment Mzt in the travel modes M7 and M8 is set to be smaller than the travel modes M3 and M4 and smaller than the travel modes M1 and M2 as shown in FIG. In the traveling mode M8 when the driver does not hold the steering wheel, the adjustment gain Kbm is set smaller than that in the traveling mode M7 in order to suppress an excessive generation of the yaw rate in the second half of the control. For example, the adjustment gain Kbm for the travel modes M7 and M8 is set similarly to the travel modes M5 and M6.

  As described above, in the traveling control system 1 according to the present embodiment, during the automatic driving control, an abnormality occurs in the acquisition of traveling environment information necessary for performing the automatic driving, and an abnormality in the steering system of the host vehicle is detected. In the case, the travel mode setting unit 11 of the travel control device 10 sets a retreat path for ensuring the safety of the host vehicle based on the travel environment information acquired last before the abnormality is detected in the acquisition of the travel environment information. The travel mode for traveling along the evacuation route is set according to the situation when an abnormality occurs. Then, the retreat travel control unit 12 of the travel control device 10 controls the deceleration and yaw moment of the host vehicle via the brake control device 21 according to the travel mode. As a result, in automatic driving control, even if an abnormality occurs in the steering system in a situation where traveling environment information is not available, safety can be ensured by guiding the vehicle to an evacuation point via an appropriate route. It becomes possible.

  In addition, by setting the travel mode for traveling along the evacuation route based on the vehicle speed of the host vehicle, the distance between the host vehicle and surrounding obstacles, and the driver's steering state, the optimal travel according to the situation at the time of occurrence of an abnormality It is possible to guide to the retreat point in the mode, and it is possible to respond quickly by selecting from a plurality of driving modes having different deceleration and yaw moment. Further, when executing the evacuation control, the occupant of the own vehicle is notified of the abnormal evacuation, and other vehicles and pedestrians around the own vehicle are notified of the abnormal evacuation of the own vehicle. Can be secured.

DESCRIPTION OF SYMBOLS 1 Travel control system 10 Travel control apparatus 11 Travel mode setting part 12 Retreat travel control part 15 Surrounding environment recognition apparatus 16 Own vehicle position information detection apparatus 17 Inter-vehicle communication apparatus 18 Road traffic information communication apparatus 19 Switch group 20 Engine control apparatus 21 Brake Control device 22 Steering control device 23 Alarm device

Claims (4)

In a vehicle travel control system that performs automatic driving control based on travel environment information of an environment in which the host vehicle travels and travel information of the host vehicle,
During the automatic driving control, if an abnormality is detected in the acquisition of the traveling environment information and an abnormality is detected in the steering system of the host vehicle, the last time before the abnormality is detected in the acquisition of the traveling environment information A travel mode setting unit that sets a retreat route for ensuring the safety of the host vehicle based on the acquired travel environment information, and sets a travel mode that travels along the retreat route according to a situation when an abnormality occurs; ,
A vehicle travel control system comprising: a retreat travel control unit that controls deceleration and yaw moment of the host vehicle via brake control according to the travel mode.   2. The vehicle travel control system according to claim 1, wherein the travel mode is set on condition of a vehicle speed of the host vehicle, a distance between the host vehicle and a surrounding obstacle, and a driver's steering state.   The vehicle travel control system according to claim 2, wherein the travel mode is selected from a plurality of travel modes having different deceleration and yaw moment according to the condition.   The abnormality retreating is notified to the occupant of the own vehicle and the other vehicle and the pedestrian around the own vehicle are informed of the abnormal retreat of the own vehicle when performing the control of the retreat traveling control unit. The vehicle travel control system according to any one of claims 3 to 4.

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