JP2016094038A - Vehicular travel control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular travel control system which, in automatic driving control, optimizes yaw moment control by a brake at the time when an abnormality occurs in a steering system, suppresses an impact of steer torque, and does not cause unnecessary deceleration.SOLUTION: When an abnormality is detected in a steering system under automatic driving, a travel control device 10 calculates a requirement yaw moment to be added to a vehicle at a requirement yaw moment calculation part 12, and adjusts the longitudinal axis distribution of brake force for generating the requirement yaw moment at a longitudinal distribution adjustment part 13. At this time, steer torque by a slip angle and steer torque by a scrub radius are estimated at a slip angle steer torque estimation part 14a and a scrub steer torque estimation part 14b, and when steer torque that can be output according to the extent of the abnormality in the steering system is smaller than the aforesaid steer torque, a control amount of brake force output to a brake control device 25 is corrected.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, in vehicles, various systems using automatic driving technology have been developed and proposed so that drivers can drive more comfortably and safely, and in such systems, countermeasures against steering system failures have been proposed. It becomes important.

  For example, Patent Document 1 discloses a technique for suppressing instability of vehicle behavior due to failure of a power steering device by compensating for the yaw moment of the vehicle by brake control when an abnormality of the power steering device is detected. Is disclosed.

JP 2008-44466 A

  However, the conventional technology disclosed in Patent Document 1 merely generates a yaw moment by brake control when the power steering device fails, and takes into account the steering torque generated by the yaw moment by the brake. Not.

  For this reason, even if an attempt is made to maintain the current lane by controlling the yaw moment by the brake until an abnormality is detected during automatic driving and the driver takes over control, the necessary yaw moment is excessive or insufficient due to the effect of the steering torque. As a result, it becomes difficult to obtain the accuracy necessary for maintaining the lane.

  For example, when performing automatic driving by recognizing a lane from a captured image of a camera, the lane position information is not updated due to a temporary stop of image recognition or a decrease in reliability, and the yaw deviation and lateral position with respect to the lane are fed back If an abnormality occurs in the steering system in a situation where it is impossible to control, even if trying to maintain the current lane by controlling the yaw moment with the brake, the influence of the steering torque cannot be ignored, and the accuracy necessary for maintaining the lane can be obtained. It becomes difficult.

  Furthermore, since the yaw moment control by the brake is accompanied by the deceleration of the vehicle, unnecessary deceleration is generated only by generating the yaw moment by the brake control, which may increase the risk of a rear-end collision from the following vehicle.

  The present invention has been made in view of the above circumstances, and in automatic operation control, the yaw moment control by the brake when an abnormality occurs in the steering system is optimized, the influence of the steering torque is suppressed, and unnecessary deceleration is generated. An object of the present invention is to provide a traveling control system for a vehicle that never happens.

  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 at least in the steering system of the vehicle, a required yaw moment calculating unit that calculates a yaw moment to be added to the vehicle by the yaw brake control, and a steering torque generated by the yaw brake control, A steer torque estimating unit that estimates according to vehicle specifications, and calculates a correction amount of the yaw moment based on the steer torque according to an abnormal state of the steering system, and generates a yaw moment corrected by the correction amount And a yaw brake correction unit for correcting the yaw brake control.

  According to the present invention, in the automatic operation control, the yaw moment control by the brake when the abnormality occurs in the steering system is optimized, the influence of the steering torque is suppressed, and unnecessary deceleration is not generated, and the yaw moment control is performed. It is possible to reduce the risk of rear-end collision from the following vehicle due to improved accuracy and unnecessary deceleration.

Overall configuration diagram of a vehicle travel control system Explanatory diagram showing the generated yaw rate and steering torque per unit brake control amount Explanatory diagram showing excess or deficiency of yaw rate An explanatory diagram showing an example of a predicted route Illustration of vehicle speed gain Explanatory diagram showing the relationship between vehicle speed and steering torque according to the scrub direction Explanatory drawing showing the adjustment area of the front and rear distribution of yaw moment Flow chart of running control at abnormal time

  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 20, a host vehicle position information detection device 21, an inter-vehicle communication device 22, a road traffic information communication device 23, an engine control device 24, a brake control device 25, a steering control device 26, an alarm. The devices 27 and the like are connected via a communication bus 100 forming an in-vehicle network, and a switch group 28 for various settings and operations is connected.

  The surrounding environment recognition device 20 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 the vehicle interior that captures image information by capturing an 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 20 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 process 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 20 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 20 (the distance to the three-dimensional object, the farthest distance of the lane marking) is used as the visibility. Furthermore, the surrounding environment recognition device 20 outputs the abnormality of the surrounding environment recognition device 20 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 21 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 22 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 23 is a so-called road traffic information communication system (VICS: Vehicle Information and Communication System: registered trademark), and from FM multiplex broadcasting or a transmitter on the road, traffic jams, 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 28 is a switch group related to the driver's driving support control. For example, the switch group 28 is a switch that controls driving at a constant speed that is set in advance, or sets the inter-vehicle distance and inter-vehicle time with the preceding vehicle 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 24 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 25 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 25 calculates the brake fluid pressure of each wheel based on the brake force, and a brake drive unit (not shown). ).

  The steering control device 26, for example, 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 26 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 preventing control from the traveling lane. A steering angle or steering torque necessary for lane departure prevention control is calculated by the travel control device 10 and input to the steering control device 26, and the electric power steering motor is driven and controlled according to the input control amount. . Further, the steering control device 26 detects abnormalities such as a steering system including a steering mechanism, a steering torque sensor, and a handle angle sensor, and the traveling control device 10 monitors the occurrence of these abnormal states. Yes.

  The alarm device 27 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.

  The travel control device 10 that is the center of the travel control system 1 having each of the above devices is based on input information and control information from each device 20 to 27, and prevents 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.

  In this automatic driving control, if an abnormality is detected at least in the steering system, the traveling control device 10 transmits the yaw moment of the vehicle necessary for traveling the vehicle along a predetermined route via the brake control device 25. The abnormal-time running control that is generated in this way is executed. In the following, an abnormality (for example, stop of image recognition, a decrease in reliability, a decrease in radar wave transmission / reception function, etc.) that prevents the travel environment information necessary for automatic driving from being normally acquired occurs and steering is performed. Assuming that an abnormality has been detected in the system, the current vehicle is currently in the period until the driver can safely take over the operation of the own vehicle or until the abnormality is temporary and returns to automatic operation. An example of executing the abnormal-time traveling control for maintaining the vehicle in the lane will be described.

  In this abnormal time travel control, the travel control device 10 sets the travel route of the host vehicle based on the travel environment information detected last before the acquisition of travel environment information becomes abnormal, and travels along the set route. The yaw moment of the vehicle necessary for this is generated via the brake control device 25.

  At this time, the yaw moment actually applied to the vehicle depends on the steering state corresponding to the degree of abnormality of the steering system. For example, when an abnormality occurs such that the electric power steering motor is locked and the handle is fixed, the steering torque of the handle does not change with respect to the generated yaw rate per unit brake control amount as shown in FIG. When an abnormality occurs that makes it impossible to control the steering angle by the steering control device 26, a steering torque is generated according to the vehicle speed under the influence of the yaw moment by the brake, and the steering angle changes.

  As a result, as shown by a broken line in FIG. 3, the required yaw rate is excessive or insufficient with respect to the generated yaw rate per unit brake control amount. Furthermore, since the yaw moment control by the brake is accompanied by the deceleration of the vehicle, it is necessary to consider so as to avoid the rear-end collision by the following vehicle.

  Therefore, the traveling control device 10 optimizes the yaw moment control by the brake according to the degree of abnormality of the steering system, prevents the required yaw moment from being excessive and insufficient, and does not cause unnecessary deceleration. I have to. For this reason, the traveling control device 10 functions as an abnormal traveling control as shown in FIG. 1, as shown in FIG. 1, an abnormal route setting unit 11, a requested yaw moment calculating unit 12, a front / rear distribution adjusting unit 13, and a steering torque estimating unit 14. The yaw brake correction unit 15 is provided.

  Specifically, for example, as illustrated in FIG. 4, the abnormal-time route setting unit 11 includes a preceding vehicle and a succeeding vehicle within a travel environment information acquisition possible range detected last before the acquisition of travel environment information becomes abnormal. A route that can safely travel in the current lane while avoiding contact with the vehicle is predicted and set as a route in an abnormal state. The example of FIG. 4 shows an example in which the route is set at the center of the lane in the left curve within the range of the visibility Lc recognized last, as indicated by a broken line in the figure.

The requested yaw moment calculation unit 12 calculates a yaw moment to be added to the vehicle so that the vehicle can safely travel along the route set by the host vehicle without contacting an obstacle such as a road boundary curb or another vehicle. Here, assuming that the curvature of the route is κc, the target handle angle θHF necessary for traveling along the route 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 travel along the set route, a difference (θHF−θH0) between the target handle angle θHF and the handle angle θH0 when the travel environment information acquisition and the steering system are determined to be abnormal is set as a required handle angle θH_vdc, The required yaw moment Mzt corresponding to the necessary handle angle θH_vdc needs to be generated by brake control via the brake control device 25. The required yaw moment Mzt generated by the brake control can be calculated by the following equation (2), for example.
Mzt = (2 · Kf · Kr) / (Kf + Kr) · (θH_vdc / n) (2)
Kf: equivalent cornering power of the front wheels
Kr: Equivalent cornering power of rear wheel

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

The front / rear distribution adjustment unit 13 adjusts the front / rear axis distribution of the braking force that generates the required yaw moment Mzt, and outputs the result to the brake control device 25. For example, when the braking force corresponding to the required yaw moment Mzt (the sum of the left and right wheel braking force difference) is My and the front / rear yaw moment distribution ratio (front yaw moment / total yaw moment) by the brake control is Ky, the yaw moment The brake force Ft for the front wheel and the brake force Rr for the rear wheel that generate the are respectively distributed as shown in the following equations (3) and (4).
Ft = Ky · My = Ky · Mzt / d (3)
Rr = (1-Ky) .My = (1-Ky) .Mzt / d (4)
Where d: vehicle tread

  When it is necessary to decelerate and stop the vehicle, a braking force corresponding to the target deceleration is applied to the front and rear wheels at a predetermined distribution ratio, and the braking forces Ft and Rr turn in the + direction on the turning inner wheel side. It is added so as to be in the negative direction on the outer ring side.

  In the present embodiment, the front / rear yaw moment distribution ratio Ky is basically a constant value, assuming that the braking force is basically distributed at a constant rate. However, a limiter process is performed in advance and output to the brake control device 25 so that one of the front and rear is not too large when converted into the brake fluid pressure.

  The steer torque estimating unit 14 estimates the steer torque generated in the steering wheel due to the influence of the yaw moment generated in the yaw brake control. Since this steer torque varies depending on vehicle specifications, in the present embodiment, a slip angle / steer torque estimation unit 14a that takes into account the slip angle of the tire, and a scrub And a steer torque estimating unit 14b.

  The slip angle / steer torque estimating unit 14a estimates the steer torque Ts from the tire slip angle β generated at the total yaw moment (required yaw moment) Mzt of the front and rear wheels. The slip angle β can be estimated by, for example, calculation using the yaw rate γ, the lateral acceleration Gy, and the vehicle speed V (Δβ / Δt = γ−Gy / V). The steer torque Ts based on the slip angle β is Basically, it has a linear characteristic with respect to the yaw moment Mzt. Therefore, a map of the yaw moment Mzt and the vehicle speed V that have been experimentally adapted in advance is held in the system, and the steering torque Ts can be estimated with reference to this map.

  The scrub / steer torque estimator 14b determines the steer torque Tscr that varies depending on the scrub radius, based on the yaw moment (Ky · Mzt) of the braking force distributed to the front wheels and the scrub radius determined by the suspension geometry of the individual vehicle. Is estimated. The steering torque Tscr by the scrub radius basically has a linear characteristic with respect to the yaw moment (Ky · Mzt) on the front wheel side, and the yaw moment (Ky · Mzt) and the vehicle speed that have been experimentally adapted in advance. A map of V is held in the system, and the steering torque Tscr can be estimated with reference to this map.

  The yaw brake correction unit 15 is based on the difference between the steer torque generated according to the slip angle and the scrub radius during the yaw moment control by the brake and the maximum steer torque that can be output according to the degree of abnormality in the steering system. Then, the yaw moment correction amount Mzh for appropriately adding the yaw moment by the brake to the vehicle is calculated. Then, the control amount of the braking force that generates the yaw moment corrected by the yaw moment correction amount Mzh is output to the brake control device 25.

  In the present embodiment, the yaw moment due to the steering torque is corrected by adding the yaw moment correction amount Mzh to the yaw moment (1-Ky) · Mzt distributed to the rear wheel to correct the braking force Rr of the rear wheel. Compensate for excess or deficiency. The yaw moment correction amount Mzh may be added to the yaw moment on the front wheel side.

Specifically, the steering torque T1 is obtained by adding the steering torque Tscr based on the scrub radius to the steering torque Ts based on the slip angle, and the difference between the steering torque T1 and the maximum steering torque T2 of the steering system that can be compensated by the steering system ( A correction amount is calculated by a predetermined function F using T1-T2). Further, as shown in the following equation (5), the correction amount F (T1-T2) is adjusted by the vehicle speed gain Gv to calculate the final correction amount Mzh.
Mzh = F (T1-T2) · Gv (5)

  Here, the correction amount Mzh according to the equation (5) is calculated under the condition of T1> T2. That is, when the steering system fails and the steering angle control becomes impossible (T2 = 0), or when the motor output is limited by the heating protection of the electric power steering motor and T1> T2, Correct the moment. In such a steering system failure state, kickback compensation by motor torque control can be used in combination.

  On the other hand, the yaw moment correction amount Mzh is set to 0 when the motor output restriction is relatively small due to a partial failure of the steering system and the steering torque T1 can be compensated (T2 ≧ T1). When the condition of T2 ≧ T1 can be satisfied in the steering system, it is possible to leave the steering torque compensation for the yaw moment generated in the brake to the steering system.

  When a steering lock state occurs such as the electric power steering motor is locked, the steering torque is not generated (T1 = 0), and the yaw brake control is performed (Mzh = 0).

  On the other hand, the vehicle speed gain Gv in the equation (5) considers that the steering torque changes due to the change of the yaw moment by the brake, and experimentally adapts the yaw moment that can cancel the yaw moment by the steering torque. And set. That is, as explained in FIG. 3 above, when the steering angle changes due to the steering torque, conversely, the vehicle speed V1 at which the steering angle change becomes 0 is obtained, and the compensation amount at this vehicle speed V1 is set to 0 to respond to the vehicle speed. Set the gain using an experimentally adapted map.

  As the map of the vehicle speed gain Gv, for example, a map having characteristics as shown in FIG. 5 can be used, and the vehicle speed gain Gv is set according to the vehicle speed V. In the example of FIG. 5, the vehicle speed gain Gv increases as the vehicle speed V becomes higher than V1, and is set to monotonously increase near V1 and saturate at a high vehicle speed (about 200 km / h).

  In the above description, the front / rear distribution of the yaw brake control is described as being constant. However, the front / rear distribution of the yaw brake control is adjusted by changing the yaw moment distribution ratio Ky so that the steering angle change due to the yaw brake control is minimized. Anyway.

  That is, the steer torque generated by the yaw brake control varies depending on the scrub radius, but if the generated steer torque is + in the same direction as the direction of the yaw moment applied by the brake, as shown in FIG. The more the scrub is in the negative direction, the steer torque that acts in the direction to cancel the yaw moment caused by the brake. Therefore, by setting the vehicle speed region for adjusting the distribution of the yaw moment to the front and rear axes by the yaw brake control based on the scrub radius, it is possible to suppress the steering angle change by the yaw brake control.

  For example, when the scrub of the vehicle is a negative scrub, as shown in FIG. 7, the steering torque becomes zero in the characteristic curve L2 of the vehicle speed Vscr1 and the scrub zero where the steering torque becomes zero in the characteristic curve L1 of the corresponding negative scrub. In the vehicle speed range between the vehicle speed Vscr2, the front-to-back distribution of the yaw moment by the yaw brake control is adjusted so that the steering torque is minimized. Also, in the region where the vehicle speed is Vscr2 or higher, the braking force is distributed only to the rear side to avoid the effect of scrub, and in the region where the vehicle speed is Vscr1 or lower, the braking force is distributed only to the front side to correct the effect of scrubbing. .

  Next, the program processing of the abnormal time traveling control executed by the traveling control device 10 will be described with reference to the flowchart shown in FIG.

  In the abnormal time traveling control, first, in the first step S101, it is determined whether or not the automatic driving state in which the automatic driving 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, a travel route for maintaining the current lane of the host vehicle is set based on the travel environment information detected last before the acquisition of the travel environment information becomes abnormal, and is set in step S105. The yaw moment (required yaw moment) Mzt generated by the brake control from the target handle angle necessary for traveling along the route is calculated based on the above-described equation (2).

  Next, the process proceeds to step S106 to adjust the front / rear distribution of the requested yaw moment Mzt, and in steps S107 and S108, the steering torque generated according to the vehicle specifications when the yaw moment is generated by the brake is estimated. In order to estimate the steering torque according to the vehicle specifications, the steering torque Ts based on the slip angle is set with reference to the map in step S107, and the steering torque Tscr based on the scrub radius is set with reference to the map in step S108. Do. For convenience, the steer torque Tscr is set after the steer torque Ts is set, but either may be performed first.

  Thereafter, the process proceeds to step S109, where the steer torque T1 obtained by adding the steer torque Ts based on the slip angle and the steer torque Tscr based on the scrub radius is compared with the maximum steer torque T2 that can be generated according to the degree of abnormality of the steering system. If T1> T2, in step S110, the yaw moment correction amount Mzh for compensating for the excess or deficiency of the yaw moment due to the steering torque T1 is calculated based on the above-described equation (5), and the process proceeds to step S112. move on.

  On the other hand, if T1 ≦ T2 in step S109 and the steering torque T1 can be compensated by the steering system, the yaw moment correction amount Mzh is set to 0 in step S111, and the process proceeds to step S112. In step S112, the yaw brake control is executed based on the requested yaw moment Mzt corrected with the yaw moment correction amount Mzh or the requested yaw moment Mzt without correction until the operation is transferred from the automatic operation to the operation by the driver, or Control is performed so that the host vehicle can travel while maintaining the current lane until the occurrence of abnormality is temporary and the vehicle returns to automatic driving.

  As described above, in this embodiment, when at least a steering system abnormality is detected under automatic driving control, the steering torque T1 based on the vehicle specifications and the steering system with respect to the yaw moment generated by the yaw brake control are detected. The brake control amount is corrected using a difference from the steerable torque T2 that can be compensated and a gain Gv corresponding to the vehicle speed.

  As a result, it is possible to suppress the influence of the steering torque and to add a yaw moment equivalent to that when the compensation by the steering system is effective to the vehicle, and without causing unnecessary deceleration, the yaw moment control can be performed. The accuracy can be improved and the risk of rear-end collision from the following vehicle can be reduced. Therefore, even if an abnormality occurs under automatic operation, the operation can be safely taken over by the driver, and if the abnormality is temporary, a smooth return to automatic operation is possible. . For example, under automatic driving based on a lane recognized from a camera image or the like, the lane position information is not updated due to a temporary stop of image recognition or a decrease in reliability, and the yaw deviation and lateral position with respect to the lane cannot be feedback controlled. Even if an abnormality occurs in the steering system under such circumstances, the influence of the steering torque on the yaw brake control can be suppressed and lane keeping accuracy can be secured, and safe driving can be taken over to the driver, A smooth return to automatic operation is possible.

DESCRIPTION OF SYMBOLS 1 Traveling control system 10 Traveling control apparatus 11 Abnormal path setting part 12 Required yaw moment setting part 13 Front-rear distribution adjustment part 14 Steer torque estimation part 14a Slip angle / steer torque estimation part 14b Scrub / steer torque estimation part 15 Yaw brake correction part DESCRIPTION OF SYMBOLS 20 Surrounding environment recognition apparatus 21 Own vehicle position information detection apparatus 22 Inter-vehicle communication apparatus 23 Road traffic information communication apparatus 24 Engine control apparatus 25 Brake control apparatus 26 Steering control apparatus Mzh Yaw moment correction amount Mzt Request yaw moment

Claims (6)

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 at least in the steering system of the vehicle, a requested yaw moment calculating unit that calculates a yaw moment to be added to the vehicle by the yaw brake control;
A steering torque estimating unit that estimates a steering torque of the steering wheel generated by the yaw brake control according to vehicle specifications;
A yaw brake correction unit that calculates a correction amount of the yaw moment based on the steering torque in accordance with an abnormal state of the steering system and corrects the yaw brake control so as to generate a yaw moment corrected by the correction amount; A vehicle travel control system comprising:   Calculating an yaw moment to be added to the vehicle by the yaw brake control when an abnormality is detected in the acquisition of the traveling environment information and an abnormality is detected in the steering system of the vehicle during the automatic driving control; The vehicle travel control system according to claim 1, wherein:   3. The vehicle travel control system according to claim 1, wherein the steering torque is a steering torque obtained by adding a steering torque corresponding to a slip angle of a tire and a steering torque corresponding to a scrub radius of the vehicle. .   The travel amount of the vehicle according to any one of claims 1 to 3, wherein the correction amount of the yaw moment is calculated when a maximum steering torque that can be generated in the steering system is smaller than the steering torque. Control system.   5. The vehicle travel control system according to claim 1, wherein the yaw moment correction amount is calculated by multiplying a correction amount based on the steering torque by a gain corresponding to a vehicle speed. .   6. The distribution of the yaw moment to the front and rear axes is adjusted so that the steering torque generated by the yaw brake control is minimized in a vehicle speed range set based on a scrub radius of the vehicle. The vehicle travel control system according to any one of the above.

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