JP2016124310A - Traveling control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling control device of a vehicle which properly suppresses ABS control in the case other than an emergency even if the ABS control is performed due to a change of a road face status during automatic drive, and does not impart incongruity to a driver.SOLUTION: When it can be determined that the safety of a vehicle is secured when ABS is operated by a change of a road face state to, for example, a low-μ road face and an uneven-μ road face from a high-μ road face, a traveling control device of a vehicle suppresses an operation of ABS control by changing brake fluid pressure Pb to brake fluid pressure which is lower than brake fluid pressure at which a tire is locked by a prescribed amount, and holding it.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle travel control device equipped with an antilock brake system (ABS) that recognizes a travel environment, detects travel information of the 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. 2014-133477 (hereinafter referred to as Patent Document 1), a technology of a driving support device that controls a host vehicle so as to travel along the target track by setting a target track from a captured image in front of the host vehicle. Is disclosed.

JP 2014-133477 A

  By the way, when braking in the automatic driving state disclosed in Patent Document 1 described above, for example, when the road surface state changes from a high μ road surface to a low μ road surface or a mottled μ road surface, a low μ road surface or a mottled μ is used. The ABS control may be activated when the vehicle moves to the road surface. In this way, when ABS control is activated due to changes in road surface conditions during automatic driving, the brake fluid pressure that locks the tire is added, the brake fluid pressure is maintained at a predetermined level, and the brake fluid pressure is reduced repeatedly. There is a possibility that the ABS control will continue to operate until the vehicle stops, although this is not an emergency case. Thus, if the ABS control continues to operate until the vehicle stops, vibration, noise, and deceleration fluctuations may occur due to the operation of the ABS control, which may cause driver discomfort.

  The present invention has been made in view of the above circumstances. Even if the road surface condition changes and the ABS control is activated during automatic driving, the ABS control is appropriately suppressed in a case other than an emergency and the driver is controlled. It is an object of the present invention to provide a travel control device for a vehicle that does not cause discomfort.

  One aspect of the vehicle travel control apparatus of the present invention includes travel environment information acquisition means for acquiring travel environment information for travel of the host vehicle, and travel information detection means for detecting travel information of the host vehicle. In the vehicle travel control device that executes the automatic driving control based on the information and the travel information of the host vehicle, the vehicle includes an anti-lock brake unit that avoids locking of the wheels, and a road surface state estimation unit that estimates the road surface state, When the anti-lock brake means is operated due to a change in the road surface state during braking in the automatic driving state, the anti-lock brake control operation of the anti-lock brake means is suppressed in the case of a preset condition. .

  According to the vehicle travel control device of the present invention, even if the road surface condition changes and the ABS control is activated during automatic driving, the ABS control is appropriately suppressed in a case other than an emergency, and the driver is not allowed. There is an excellent effect of not giving a pleasant feeling.

1 is an overall configuration diagram of a vehicle travel control device according to an embodiment of the present invention. It is a flowchart of the ABS control program in an automatic driving | running state by one Embodiment of this invention. It is a time chart which shows an example of change of brake fluid pressure by ABS control by one embodiment of the invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In FIG. 1, reference numeral 1 denotes a vehicle travel control device. The travel control device 1 includes a travel control unit 10, a surrounding environment recognition device 11, a travel parameter detection device 12, a host vehicle position information detection device 13, Each input device of the inter-vehicle communication device 14, the road traffic information communication device 15, and the switch group 16, and the output devices of the engine control device 21, the brake control device 22, the steering control device 23, the display device 24, and the speaker / buzzer 25 are provided. It is connected.

  The surrounding environment recognition device 11 includes a camera device (stereo camera, monocular camera, color camera, etc.) provided with a solid-state imaging device or the like provided in a vehicle interior that captures image information by capturing an external environment of the vehicle, 1 is constituted by a radar device (laser radar, millimeter wave radar, etc.) for receiving a reflected wave from a three-dimensional object, sonar (not shown).

  The surrounding environment recognition device 11 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 11 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. Thus, the surrounding environment recognition device 11 is provided as a traveling environment information acquisition unit.

  The travel parameter detection device 12 travels information about the host vehicle, specifically, the vehicle speed V, the steering torque Tdrv, the steering wheel angle θH, the yaw rate γ, the accelerator opening, the throttle opening, and the road surface gradient Ug (climbing). The directional gradient is “+”), and the road surface friction coefficient estimated value μe and the like are detected. Thus, the travel parameter detection device 12 is provided as travel information detection means and road surface state estimation means.

  The own vehicle position information detection device 13 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 and stored 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). When the vehicle position on the map position is displayed and a destination is input by the operator, a route from the departure point to the destination is calculated in a predetermined manner and displayed on a display device 24 such as a display or a monitor. In addition, the speaker / buzzer 25 can be guided by voice guidance. Thus, the own vehicle position information detection device 13 is provided as a travel environment information acquisition unit.

  The inter-vehicle communication device 14 is composed of, for example, a narrow-area wireless communication device having a communication area of about 100 [m] such as a wireless LAN, and directly communicates with other vehicles without passing through a server or the like to transmit and receive information. It is possible to do. And vehicle information, traveling information, traffic environment information, etc. are exchanged by mutual communication with other vehicles. The vehicle information includes specific 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. Thus, the inter-vehicle communication device 14 is provided as a travel environment information acquisition unit.

  The road traffic information communication device 15 is a so-called road traffic information communication system (VICS: Vehicle Information and Communication System: registered trademark), and is used for FM congestion broadcasting, a transmitter on the road, congestion, accidents, construction, required time, parking. The road traffic information of the car park is received in real time, and the received traffic information is displayed on the previously stored map data. Thus, the road traffic information communication device 15 is provided as a travel environment information acquisition unit.

  The switch group 16 is a switch group related to the driver's driving support control. For example, the switch group 16 is a switch that controls traveling at a constant speed that is set in advance, or a distance between the preceding vehicle and an inter-vehicle time are set 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 21 uses, for example, a fuel for a vehicle engine (not shown) based on the intake air amount, throttle opening, engine water temperature, intake air temperature, oxygen concentration, crank angle, accelerator opening, and other vehicle information. This is a known control unit that performs main control such as injection control, ignition timing control, and control of an electronically controlled throttle valve.

  The brake control device 22 controls a four-wheel brake device (not shown) independently of a driver's brake operation based on, for example, a brake switch, four-wheel wheel speed, steering wheel angle, yaw rate, and other vehicle information. This is a known control unit that performs a known yaw brake control for controlling a yaw moment applied to the vehicle, such as a known ABS control or a side slip prevention control.

  The ABS control in the brake control device 22 is performed in a normal operation state that is not an automatic operation state, for example, when a preset wheel deceleration is reached (time t1) as shown in the time chart of FIG. When the brake fluid pressure Pb is suppressed to the brake fluid pressure PbN, the brake fluid pressure Pb is maintained (time t1 to time t2), and then the tire slip ratio exceeds a preset value. (Time t2), the brake fluid pressure Pb is reduced (to time t3), and thereafter the brake fluid pressure Pb is maintained (time t3 to time t4) → the brake fluid pressure Pb is increased (time t4 to) →. Repeatedly. However, when it is determined that the safety of the vehicle can be ensured when the road surface condition is changed from a high μ road surface to a low μ road surface or a mottled μ road surface during braking in the automatic driving state, for example. The brake fluid pressure Pb is lower than the brake fluid pressure at which the tire locks (the above-described brake fluid pressure PbN), which is lower than the brake fluid pressure (the brake fluid pressure PbN that is reduced by normal ABS control). The brake fluid pressure (PbL) set by the above is changed and held, and the operation of the ABS control is suppressed. Thus, the brake control device 22 has a function as antilock brake means.

In addition, when the target deceleration (d ² X / dt ² ) t or the braking force of each wheel is input from the traveling control unit 10, the brake control device 22 is configured to output the target deceleration (d ² X / dt). ² ) The brake fluid pressure of each wheel is calculated based on t and the brake force of each wheel, and a brake drive unit (not shown) is operated.

  The steering control device 23 controls the assist torque by an electric power steering motor (not shown) provided in the vehicle steering system based on, for example, vehicle speed, steering torque, steering wheel angle, yaw rate, and other vehicle information. It is a control device. In addition, the steering control device 23 maintains the above-mentioned traveling lane in the set lane and performs lane keeping control for performing traveling control, lane departure preventing control for performing departure prevention control from the traveling lane, and automatic driving steering for executing these in coordination. The steering control device 10 calculates the steering angle, target steering angle θHt, or steering torque necessary for lane keeping control, lane departure prevention control, automatic driving steering control, and the steering control device. The electric power steering motor is driven and controlled in accordance with the input control amount.

  The display device 24 is a device that provides a visual warning and notification to drivers such as a monitor, a display, and an alarm lamp. The speaker / buzzer 25 is a device that gives an audible warning and notification to the driver.

  Then, the traveling control unit 10 is configured to prevent collisions with obstacles, constant speed traveling control, follow-up traveling control, lane keeping control, lane departure prevention control based on the input signals from the devices 11 to 16 described above. In addition, automatic driving control or the like is executed by performing overtaking control or the like in cooperation.

  Next, the ABS control in the automatic driving state executed by the brake control device 22 will be described with reference to the flowchart of FIG.

  First, in step (hereinafter, abbreviated as “S”) 101, it is determined whether or not the automatic operation state in which the automatic operation control is being executed. If it is not the automatic operation state, the program is exited. Advances to S102.

  When the process proceeds to S102, it is determined whether or not the brake is being performed. If the brake is being performed, the process proceeds to S103, and if the brake is not being performed, the program is directly exited.

  When it is determined that braking is being performed in S102 and the process proceeds to S103, it is determined whether or not the ABS is operated by the brake control device 22.

  If it is determined that the ABS is activated as a result of the determination in S103, the process proceeds to S104. If the ABS was not activated last time, the ABS is activated. If the ABS is already activated, the process proceeds to S104. Then, the operation of the ABS is continued as it is, and the process proceeds to S105 to stop the vehicle and exit the program.

  If the ABS is determined to be inoperative as a result of the determination in S103, the process proceeds to S106, and whether the road surface condition has changed from a high μ road surface to a low μ road surface or a mottled μ road surface, for example, has the ABS operated. Is determined. As a result of the determination, if the ABS is not activated due to a change in the road surface condition, the program is left as it is, and if it is determined that the ABS is activated due to a change in the road surface condition, the process proceeds to S107.

  If it is determined in S106 that the ABS has been activated due to a change in the road surface condition and the process proceeds to S107, it is determined whether or not a preset ABS suppression condition is satisfied. The determination of S107 is not the situation where the current braking state is when the ABS suppression condition is not satisfied, such as an emergency in which the ABS is activated and stopped, or the ABS is not activated (a situation that seems to be safe: Whether the ABS suppression condition is satisfied).

  If it is determined in S107 that the current braking state is when the ABS suppression condition is not satisfied such as an emergency that activates and stops the ABS, the process proceeds to S104, and the ABS has not been activated last time. Operates the ABS, and if the ABS has already been operated, continues the operation of the ABS as it is, proceeds to S105, stops the vehicle, and exits the program.

  Here, the ABS suppression condition will be specifically described.

  During high-speed driving that has been set in advance, if the ABS operation is suppressed, the vehicle behavior may be disturbed due to fluctuations in the brake fluid pressure Pb, so the ABS suppression condition is not satisfied and the ABS operation continues. To do.

  If the deceleration before ABS operation is high, there is a possibility of an emergency. Therefore, in order not to give the driver anxiety, the lateral grip force of the tire is maintained as the ABS suppression condition is not satisfied. In order to ensure steering performance, the ABS is operated and continued.

  Furthermore, for example, if the steering angle is equal to or greater than a predetermined value or the lateral acceleration is equal to or greater than a predetermined value and it can be determined that the vehicle is turning, if the operation of the ABS is suppressed, the vehicle behavior is caused by fluctuations in the brake hydraulic pressure Pb. Since the ABS suppression condition is not satisfied, the ABS operation is continued as it is.

  In addition, during braking, for example, when image information from the surrounding environment recognition device 11 requires emergency avoidance of the front three-dimensional object, in order to maintain the grip force in the lateral direction of the tire and ensure steering performance, The ABS is operated and continued as the ABS suppression condition is not satisfied.

  Furthermore, obstacles and preceding objects are detected ahead by image information from the surrounding environment recognition device 11, map information from the vehicle position information detection device 13, and communication information from the inter-vehicle communication device 14 and the road traffic information communication device 15. When there is a car, or when an obstacle or a preceding car is expected, if there is a sufficient distance to the obstacle (if it is more than a preset distance), a collision is prevented. When the road surface μ changes within the marginal deceleration zone to which the braking force is applied, it is determined that the safety of the vehicle is secured, and as the ABS suppression condition is established, the brake fluid pressure Pb is set to be higher than the brake fluid pressure at which the tire locks. The brake fluid pressure is changed to a predetermined low pressure and control (holding) is performed to suppress the operation of the ABS, thereby preventing the driver from feeling uncomfortable due to fluctuations in vibration, sound, and deceleration. On the contrary, when the distance to the obstacle is shorter than the previously set distance, the operation of the ABS is not suppressed in order not to give the driver anxiety or to ensure steering performance. Note that the preset distance may be determined by the inter-vehicle time THW, the collision allowance time TTC, or the like.

  In S107 described above, when the ABS suppression condition is satisfied and the process proceeds to S108, the brake fluid pressure Pb increase restriction control is performed, the brake fluid pressure Pb is changed to the brake fluid pressure that the tire locks and held, and the operation of the ABS control is suppressed. .

  Next, the routine proceeds to S109, where it is determined whether there is a change in the road surface μ and the vehicle speed V exceeds a preset extremely low speed Vcmin (V> Vcmin), which is the ABS operable speed, and the road surface μ If there is a change in V and V> Vcmin, the processing from S107 is repeated again.

  If it is determined in S109 that there is a change in the above-mentioned road surface μ and the condition of V> Vcmin is not satisfied, the process proceeds to S105, the vehicle is stopped and the program is exited.

  Thus, according to the embodiment of the present invention, during braking in the automatic driving state, when the ABS is activated when the road surface state changes from a high μ road surface to a low μ road surface or a mottled μ road surface, for example, If it can be determined that the safety of the vehicle is secured, the brake fluid pressure Pb is changed to a brake fluid pressure that is lower than the brake fluid pressure at which the tire locks and is held, and the ABS control operation is suppressed. Therefore, even if the road surface condition changes and the ABS control is activated during automatic driving, the ABS control is appropriately suppressed in cases other than emergency, and the driver feels uncomfortable with fluctuations in vibration, sound, and deceleration. I don't feel

DESCRIPTION OF SYMBOLS 1 Traveling control apparatus 10 Traveling control part 11 Surrounding environment recognition apparatus (traveling environment information acquisition means)
12 Travel parameter detection device (travel information detection means, road surface state estimation means)
13 Self-vehicle position information detection device (running environment information acquisition means)
14 Vehicle-to-vehicle communication device (running environment information acquisition means)
15 Road traffic information communication device (traveling environment information acquisition means)
16 switch group 21 engine control device 22 brake control device (anti-lock brake means)
23 Steering control device 24 Display device 25 Speaker buzzer

Claims (4)

A driving environment information acquiring means for acquiring driving environment information in which the host vehicle travels and a driving information detecting means for detecting driving information of the host vehicle are provided, and automatic driving is performed based on the driving environment information and the driving information of the host vehicle. In a vehicle travel control device that executes control,
Anti-lock braking means to avoid wheel locking;
Road surface state estimating means for estimating the road surface state,
When the anti-lock brake means is operated due to a change in the road surface state during braking in the automatic driving state, the anti-lock brake control operation of the anti-lock brake means is suppressed in the case of a preset condition. A travel control device for a vehicle.   The suppression of the anti-lock brake control operation of the anti-lock brake means is to change and hold the brake hydraulic pressure lower than the hydraulic pressure at which the tire locks, and to suppress the anti-lock brake control operation. The vehicle travel control apparatus according to claim 1, wherein: The road surface state estimating means is for estimating a friction coefficient of a road surface,
3. The vehicle travel control apparatus according to claim 1, wherein the change in the road surface state is a change in a road surface friction coefficient.   4. The pre-set condition for suppressing the anti-lock brake control of the anti-lock brake means is a condition for determining that the safety of the vehicle can be ensured. The vehicle travel control device according to any one of the above.

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