JP2022182807A - Vehicular travel control method and vehicular travel control device - Google Patents

Abstract

To provide a vehicular travel control method and a vehicular travel control device each of which enables reduction of a mechanical load upon an emergency stop, thereby enabling a vehicle-stopped state to be maintained.SOLUTION: When an abnormality state of a brake control device 20 is detected, deceleration of an own vehicle V1 is started, and after an output value of wheel speed or an output value of an output rotary shaft has reached 0, a shift range of a speed change gear 182 is set to a parking position without using a hydraulic friction brake.SELECTED DRAWING: Figure 6

Description

The present invention relates to a vehicle travel control method and a vehicle travel control device.

In an autonomous vehicle, when the emergency stop switch is pressed, an on-board brake system that brakes the wheels using an accumulator actuator that supplies hydraulic pressure to the brake unit by releasing hydraulic fluid that has been stored in a pressurized state in advance. is known (Patent Document 1).

Japanese Patent Application Laid-Open No. 2021-006442

However, continuing to brake the vehicle with hydraulic brakes during an emergency stop poses a problem of a large mechanical load.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle running control method and a vehicle running control device that can maintain a stopped state by reducing a mechanical load during an emergency stop.

According to the present invention, when an abnormal state of the brake control device is detected, deceleration of the own vehicle is started, and after the output value of the wheel speed or the output value of the output rotary shaft becomes 0, the hydraulic friction brake is applied. The above problem is solved by setting the shift range of the transmission to the parking position without using the

According to the present invention, it is possible to reduce the mechanical load during an emergency stop and maintain the stopped state of the vehicle.

1 is a block diagram showing an embodiment of a vehicle running control device according to the present invention; FIG. 2 is a front view showing part of the input device of FIG. 1; FIG. FIG. 2 is a plan view showing an example of lane change control of the cruise control device of FIG. 1; 2 is a block diagram showing an example of a braking control device included in the travel control device of FIG. 1; FIG. FIG. 5 is a plan view showing an example of braking control executed by the braking control device of FIG. 4; FIG. 5 is a flowchart showing an example of processing executed by the braking control device of FIG. 4; FIG.

<<Configuration of Travel Control Device>>
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a vehicle running control device 1 according to this embodiment. The cruise control device 1 of the present embodiment is also an embodiment for carrying out the vehicle cruise control method according to the present invention.

As shown in FIG. 1, the cruise control device 1 of this embodiment includes a sensor 11, a vehicle position detection device 12, a map database 13, an in-vehicle device 14, a navigation device 15, a presentation device 16, an input device 17, and a drive control device. 18 a , a steering control device 18 b , a control device 19 and a braking control device 20 . These devices are connected, for example, by a CAN (Controller Area Network) or other in-vehicle LAN, and can mutually transmit and receive information.

A sensor 11 detects the running state of the host vehicle. For example, the sensors 11 may include a front camera that captures the front of the vehicle, side cameras that capture the left and right sides of the vehicle, rear cameras that capture the rear of the vehicle, and obstacles in front of the vehicle. forward radar that detects obstacles behind the vehicle, side radar that detects obstacles on the left and right sides of the vehicle, vehicle speed sensor that detects the vehicle speed, and the driver turning the steering wheel Examples include a touch sensor (capacitance sensor) that detects whether or not the device is held, and an in-vehicle camera that captures an image of the driver. As the sensor 11, one of the plurality of sensors described above may be used, or two or more types of sensors may be used in combination. The detection result of the sensor 11 is output to the control device 19 at predetermined time intervals.

The own vehicle position detection device 12 includes a GPS unit, a gyro sensor, a vehicle speed sensor, and the like. The own vehicle position detection device 12 detects radio waves transmitted from a plurality of satellite communications by the GPS unit, and periodically acquires the position information of the own vehicle. The vehicle position detection device 12 also detects the current position of the vehicle based on the acquired position information of the vehicle, the angle change information acquired from the gyro sensor, and the vehicle speed acquired from the vehicle speed sensor. Position information of the vehicle detected by the vehicle position detection device 12 is output to the control device 19 at predetermined time intervals.

The map database 13 is a memory that stores three-dimensional high-precision map information including position information of various facilities and specific points, and is accessible from the control device 19 . The three-dimensional high-precision map information is three-dimensional map information based on road shapes detected when a data acquisition vehicle is used to travel on actual roads. The three-dimensional high-precision map information, together with the map information, includes detailed and high-precision information such as curved roads and their curve sizes (e.g., curvature or radius of curvature), road junctions, junctions, toll booths, and locations where the number of lanes decreases. is map information associated as three-dimensional information. However, the map information stored in the map database of the present invention is not limited to 3D high-precision map information, and may be other map information.

The in-vehicle device 14 is various devices mounted in the vehicle, and is operated by the driver's operation. Such in-vehicle devices include steering wheels, accelerator pedals, brake pedals, direction indicators, wipers, lights, horns, and other specific switches. The in-vehicle device 14 outputs the operation information to the control device 19 when operated by the driver.

The navigation device 15 acquires the current position information of the own vehicle from the own vehicle position detection device 12, and superimposes the position of the own vehicle on the map information for guidance and displays it on a display or the like. The navigation device 15 also has a navigation function of calculating a route to the destination when the driver inputs the destination and guiding the driver along the set route. With this navigation function, the navigation device 15 displays the route to the destination on the map on the display, and notifies the driver of the recommended driving behavior on the route by voice or the like.

The presentation device 16 includes various displays such as a display included in the navigation device 15, a display incorporated in the rearview mirror, a display incorporated in the meter section, and a head-up display projected onto the windshield. Also, the presentation device 16 includes devices other than the display, such as a speaker of an audio device, a seat device in which a vibrating body is embedded, and the like. The presentation device 16 informs the driver of various presentation information under the control of the control device 19 .

The input device 17 is, for example, a device such as a button switch that allows manual input by the driver, a touch panel that is arranged on a display screen, or a microphone that allows driver's voice input. In this embodiment, the driver can input setting information for the presentation information presented by the presentation device 16 by operating the input device 17 . FIG. 2 is a front view showing part of the input device 17 of the present embodiment, and shows an example of button switches arranged on the spokes of a steering wheel or the like.

The illustrated input device 17 is a button switch used when setting ON/OFF of the autonomous travel control function (autonomous speed control function and autonomous steering control function) provided in the control device 19 . Details of the autonomous cruise control function including the autonomous speed control function and the autonomous steering control function will be described later. The input device 17 of this embodiment includes a main switch 171 , a resume/accelerate switch 172 , a set/coast switch 173 , a cancel switch 174 , a distance control switch 175 , and a lane change support switch 176 .

The main switch 171 is a switch for turning ON/OFF the power of the system that realizes the autonomous speed control function and the autonomous steering control function of the control device 19 . The resume/accelerate switch 172 turns off the autonomous speed control function once, and then resumes the autonomous speed control function at the set speed before turning it off, or the preceding vehicle (another vehicle traveling in the same lane as the host vehicle. The same applies in this specification), and then the vehicle is stopped and then restarted by the control device 19, or for an acceleration operation to increase the set speed. The set/coast switch 173 is a switch for performing a set operation to start the autonomous speed control function at the running speed and a coast operation to lower the set speed. The cancel switch 174 is a switch for turning off the autonomous speed control function. The inter-vehicle distance adjustment switch 175 is a switch for setting the inter-vehicle distance to the preceding vehicle, and is a switch for selecting one from a plurality of settings such as short distance, medium distance, and long distance. The lane change support switch 176 is a switch for accepting the start of lane change when the control device 19 confirms the start of the lane change with the driver. By pressing the lane change support switch 176 longer than a predetermined time after accepting the start of the lane change, the acceptance of the lane change proposal by the control device 19 can be cancelled.

In addition to the button switch group shown in FIG. 2 , a direction indicator lever of a direction indicator or other switches of the vehicle-mounted device 14 can be used as the input device 17 . For example, when the control device 19 proposes whether or not to change lanes by autonomous control, the driver turns on the switch of the direction indicator to input approval or permission of the lane change. can also Further, when the control device 19 suggests whether or not to change lanes by autonomous control, when the driver operates the direction indicator lever, the direction indicator lever is operated instead of the proposed lane change. It is also possible to adopt a configuration in which a lane change is performed by The setting information input by the input device 17 is output to the control device 19 .

The drive control device 18a controls the running of the host vehicle in various ways. For example, when the self-vehicle runs at a set speed by the autonomous speed control function, the drive control device 18a accelerates, decelerates, and maintains the running speed so that the self-vehicle reaches the set speed. Operation of the drive mechanism (in the case of a gasoline engine vehicle, the operation of the internal combustion engine; in the case of an electric vehicle, the operation of the drive motor; in the case of a hybrid vehicle, the torque distribution between the internal combustion engine and the drive motor). and control the braking action. In addition, the drive control device 18a realizes acceleration/deceleration and travel speed so that the distance between the vehicle and the preceding vehicle is constant when the vehicle follows the preceding vehicle by the autonomous speed control function. control the operation of the drive mechanism and brake operation for

Further, the steering control device 18b performs steering control of the own vehicle by controlling the operation of the steering actuator in addition to the operation control of the drive mechanism and brake described above by the autonomous steering control function. For example, when the steering control device 18b executes lane keeping control by the autonomous steering control function, the steering control device 18b detects the lane marker of the own lane (the lane in which the own vehicle travels; hereinafter the same applies in this specification), and the own vehicle The traveling position of the own vehicle in the width direction is controlled so that the own vehicle travels at a predetermined position within the own lane. Further, the steering control device 18b controls the traveling position of the own vehicle in the width direction so that the own vehicle changes lanes when lane change support is executed by a lane change support function described later. Further, the steering control device 18b performs running control to turn right or left at an intersection or the like when executing right/left turn support by the autonomous steering control function. Note that the steering control device 18b controls the running of the host vehicle according to instructions from the control device 19, which will be described later. Other known methods can also be used as the travel control method by the steering control device 18b.

The control device 19 includes a ROM (Read Only Memory) that stores a program for controlling the running of the vehicle, a CPU (Central Processing Unit) that executes the program stored in the ROM, and an accessible storage device. Equipped with functioning RAM (Random Access Memory). In addition, as the operation circuit, instead of or together with the CPU (Central Processing Unit), MPU (Micro Processing Unit), DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc. can be used.

<<Function realized by the control device 19>>
The control device 19 has a running information acquisition function for acquiring information about the running state of the own vehicle, a running scene determination function for determining the running scene of the own vehicle, and a running scene determining function for determining the running scene of the own vehicle. and an autonomous cruise control function that autonomously controls the running speed and/or steering of the vehicle. Each function of the control device 19 will be described below.

The travel information acquisition function of the control device 19 is a function for the control device 19 to acquire travel information regarding the travel state of the own vehicle. For example, the control device 19 acquires image information of the exterior of the vehicle captured by the front camera, rear camera, and side camera of the sensor 11 as travel information. In addition, the control device 19 acquires detection results from the front radar, the rear radar, and the side radar as travel information. Furthermore, the control device 19 also receives vehicle speed information of the own vehicle detected by the vehicle speed sensor of the sensor 11, attitude angle and yaw rate of the own vehicle detected by the gyro sensor, and image information of the driver's face captured by the in-vehicle camera. Acquired as driving information.

Further, the control device 19 acquires current position information of the vehicle from the vehicle position detection device 12 as travel information. Further, the control device 19 acquires the set destination and the route to the destination from the navigation device 15 as travel information. Further, the control device 19 acquires location information such as curved roads and their curve sizes (e.g., curvature or radius of curvature), junctions, junctions, toll gates, and locations where the number of lanes decreases from the map database 13 as travel information. do. In addition, the control device 19 acquires operation information of the vehicle-mounted device 14 by the driver from the vehicle-mounted device 14 as driving information. The above is the travel information acquisition function realized by the control device 19 .

The driving scene determination function of the control device 19 refers to a table stored in the ROM of the control device 19 to determine the driving scene in which the host vehicle is running. A table stored in the ROM of the control device 19 stores, for example, driving scenes suitable for changing lanes and overtaking and determination conditions for each driving scene. The control device 19 refers to the table stored in the ROM and determines whether or not the driving scene of the own vehicle is suitable for, for example, changing lanes or overtaking.

For example, the judgment conditions for the "catch-up scene" include "preceding vehicle exists in front", "preceding vehicle speed < own vehicle's set speed", "predetermined time to reach the preceding vehicle", and Suppose that four conditions are set, that is, "the lane change direction is not a lane change prohibition condition." In this case, the control device 19, for example, the detection result by the front camera and the front radar included in the sensor 11, the vehicle speed detected by the vehicle speed sensor, the position information of the vehicle by the vehicle position detection device 12, and the like. Based on this, it is determined whether or not the host vehicle satisfies the above conditions. When the above conditions are satisfied, the control device 19 determines that the subject vehicle is in a "catch-up scene with the preceding vehicle". The driving scene determination function realized by the control device 19 has been described above.

The autonomous driving control function of the control device 19 is a function for the control device 19 to autonomously control the driving of the own vehicle without depending on the driver's operation. The autonomous travel control function of the control device 19 includes an autonomous speed control function that autonomously controls the travel speed of the vehicle, and an autonomous steering control function that autonomously controls the steering of the vehicle. It should be noted that autonomous control without relying on the operation of the driver also includes performing some operations by the driver. Also, the autonomous speed control function and the autonomous steering control function may be functions independent of each other or may be functions related to each other. The autonomous speed control function and the autonomous steering control function of this embodiment will be described below.

When a vehicle ahead is detected, the autonomous speed control function sets the vehicle speed set by the driver as the upper limit and controls the distance between the vehicles according to the vehicle speed while following the vehicle ahead. If the vehicle is not detected, it will run at a constant speed set by the driver. The former is also called inter-vehicle control, and the latter is called constant speed control. The autonomous speed control function detects the speed limit of the road on which the vehicle is traveling from the road signs by the sensor 11, or acquires the speed limit from map information in the map database 13, and automatically adjusts the speed limit to the set vehicle speed. may include the ability to

To activate the autonomous speed control function, the driver first operates the resume/accelerate switch 172 or the set/coast switch 173 of the input device 17 shown in FIG. 2 to input a desired running speed. For example, if the set coast switch 173 is pressed while the vehicle is traveling at 70 km/h, the current traveling speed is set as is. The set speed can be increased by pressing the switch 172 multiple times. The "+" mark attached to the resume/accelerate switch 172 indicates that it is a switch for increasing the set value. Conversely, if the speed desired by the driver is 60 km/h, the set coast switch 173 should be pressed a plurality of times to lower the set speed. The "-" mark attached to the set/coast switch 173 indicates that it is a switch that decreases the set value. Further, the driver's desired inter-vehicle distance can be selected by operating the inter-vehicle distance adjustment switch 175 of the input device 17 shown in FIG.

Constant-speed control, in which the vehicle travels at a constant speed set by the driver, is executed when the forward radar of the sensor 11 or the like detects that there is no preceding vehicle ahead of the own lane. In the constant speed control, the drive control device 18a controls the operation of the drive mechanism such as the engine and the brake while feeding back the vehicle speed data from the vehicle speed sensor so as to maintain the set running speed.

The inter-vehicle distance control, in which the vehicle follows the preceding vehicle while performing the inter-vehicle distance control, is executed when the forward radar of the sensor 11 or the like detects that there is a preceding vehicle ahead of the own lane. In the inter-vehicle distance control, the driving mechanism such as the engine and the brake is operated by the drive control device 18a while feeding back the inter-vehicle distance data detected by the forward radar so as to maintain the set inter-vehicle distance with the set traveling speed as the upper limit. controls the behavior of Note that when the preceding vehicle stops while traveling under inter-vehicle distance control, the host vehicle also stops following the preceding vehicle. Further, when the preceding vehicle starts moving within, for example, 30 seconds after the own vehicle stops, the own vehicle also starts and starts the follow-up running by the vehicle-to-vehicle distance control again. If the own vehicle has been stopped for more than 30 seconds, it will not automatically start even if the preceding vehicle starts moving. , the follow-up running is started again by the vehicle-to-vehicle distance control.

On the other hand, the autonomous steering control function is a function for executing steering control of the own vehicle by controlling the operation of the steering actuator. The autonomous steering control function of the present embodiment includes (1) a lane keeping function (lane width direction maintaining function) that controls the steering so that the driver runs in the center of the lane, for example, and assists the driver in operating the steering wheel; ) When the driver operates the turn signal lever, the steering is controlled, and the lane change assist function assists the steering operation required to change lanes. (4) If the driver has set a destination in the navigation device, etc., the vehicle will run according to the route. When the vehicle arrives at the lane change point required to change lanes, a display is displayed to confirm the driver's intention to change lanes. . When the autonomous steering control is executed, the autonomous speed control is also executed at the same time, but the speed control may be executed by the driver's accelerator/brake operation.

Here, the lane change support function among the autonomous steering control functions will be described. Autonomous speed control is also executed at the same time as lane change assistance. FIG. 3 is a plan view showing an example of lane change control (lane change support function) executed by the control device 19 of the present embodiment. As shown in FIG. 3, when the driver operates the turn signal lever of the host vehicle V1, the control device 19 turns on the direction indicator, and when a preset lane change start condition is satisfied, the lane change operation LCP (Lane Change Process, LCP) is satisfied. refers to a series of processing for autonomous lane change.) is started. The control device 19 determines whether or not a lane change start condition is satisfied based on various types of travel information acquired by the sensor 11 . Conditions for starting a lane change are not particularly limited, but (1) the vehicle is in lane keep mode, (2) the driver is holding the steering wheel, and (3) the vehicle is traveling at a speed of 60 km/h or more. , (4) there is a lane in the lane change direction, (5) there is a lane changeable space in the destination lane, (6) the lane marker type is lane changeable, (7) the road For example, all the conditions (1) to (8) are satisfied, such as the radius of curvature being 250 m or more, and (8) the driver operating the direction indicator lever within 1 second. When the control device 19 determines that the lane change start condition is satisfied by the lane change support function without an instruction from the driver, the control device 19 notifies the driver through the presentation device 16, thereby proposing a lane change to the driver. You may

When the lane change start condition is satisfied, the control device 19 starts the lane change operation LCP. As shown in FIG. 3, the lane change operation LCP of the present embodiment includes lateral movement of the vehicle V1 toward the adjacent lane L2 within the vehicle lane L1, and crossing of the lane marker from the vehicle V1 from the vehicle lane L1. Lane Change Manipulation (LCM) for moving to the adjacent lane L2. While the lane change operation LCP is being performed, the control device 19 presents information indicating that the lane is being changed by autonomous control to the driver via the presentation device 16 to urge the driver to pay attention to the surroundings. When the lane change maneuver LCM is completed, the control device 19 turns off the direction indicator and starts executing the lane keeping function in the adjacent lane L2. Note that the lane change operation LCP refers to the period from turning on the direction indicator by operating the turn signal lever to turning off the turn signal, and the lane change operation LCM is performed when the own vehicle V1 starts stepping on the boundary line between the own lane L1 and the adjacent lane L2. It refers to the period from the start to the end of the step.

Now, when driving autonomously using the autonomous driving control function, there are cases where an emergency stop becomes necessary, such as when control malfunction occurs due to a system malfunction, or when the driver becomes unable to operate the vehicle. In the prior art document cited in the conventional document, when the emergency stop switch is pressed, the pressure accumulation type actuator that supplies hydraulic pressure to the brake unit by releasing the hydraulic fluid that has been stored in a pressurized state in advance is used. Braking the wheels is described. However, continuous braking of the vehicle by the hydraulic brake imposes a large mechanical load, and it is difficult to continuously maintain the stopped state of the vehicle. Therefore, after decelerating with a hydraulic friction brake, it is common to use an electric parking brake (hereinafter also simply referred to as a parking brake) to maintain the stopped state. However, such means cannot be used when the parking brake is disabled.

Therefore, in the vehicle running control device 1 according to the present embodiment, when an abnormal state such as failure of the parking brake or interruption of the input signal from the system that controls the parking brake is detected, the host vehicle is first decelerated. Let This deceleration of the own vehicle can be performed using a hydraulic friction brake, or alternatively or in addition to the hydraulic friction brake, using an engine brake and/or a regenerative brake of a drive motor. can also In the following description, an example in which a hydraulic friction brake is applied to decelerate the own vehicle will be described. After decelerating the own vehicle, when it is determined that the output value of the wheel speed detected by the sensor or the output value of the output rotary shaft is 0, that is, the vehicle is in a stopped state where the vehicle speed is not detected, the shift range of the transmission is changed. Set to parking position. An embodiment of braking control using the braking control device 20 will be described below with reference to FIGS. 4 and 5. FIG.

FIG. 4 is a block diagram showing an outline of the braking control device 20 according to the embodiment of the invention shown in FIG. As shown in FIG. 4, the braking control device 20 of this embodiment includes an ADC (Assisted and automated Driving Control) unit 21, a VDC (Vehicle Dynamics Control) unit 22, and an EBA (Emergency Brake Assist) unit 23. A signal or information from an output rotary shaft sensor 181 as the drive control device 18a is read into this, and the final command value is output to the VDC unit 22, the EBA unit 23 and the transmission 182. The VDC unit 22 corresponds to an example of the first braking control device of the present invention, and the EBA unit 23 corresponds to the second braking control device.

The ADC unit 21 executes control for driving support and autonomous driving of the vehicle. The ADC unit 21 implements a drive control function and a braking control function by having the CPU execute a program stored in the ROM of the controller. The ADC unit 21 reads the required driving force of the driver from the accelerator pedal sensor and the required braking force from the brake pedal sensor as the sensor 11, detects the current vehicle speed with the vehicle speed sensor, and monitors the state of the vehicle. A command value corresponding to the state of (1) is output to each device of the drive control device 18a and the braking control device 20. As shown in FIG.

VDC unit 22 includes VDCCU 221 , wheel speed sensor 222 , and electric parking brake 223 , and constitutes a main system control unit of braking control device 20 . The EBA unit 23 includes an EBACU 231 and a wheel speed sensor 232, and constitutes a sub system control unit that backs up the main system control unit. Braking control during normal operation is mainly performed by the VDC unit 22 of the main system control unit controlling the electric parking brake 223 and the EBA unit 23 based on signals and information from the ADC unit 21 . However, if an abnormal condition is detected in the VDC unit 22, braking control can be executed using only the EBA unit 23 of the sub-system control unit. , the braking control can also be performed using only the VDC unit 22 of the main system control unit.

The ADC unit 21 also has an emergency stop control function. Specifically, when an abnormality such as a failure of each device provided in the VDC unit 22 and the EBA unit 23 or a system error is detected, an emergency stop control MRM (Minimum Risk Maneuver) is activated to perform emergency stop control of the vehicle. Run. The emergency stop control MRM is a control that automatically stops the vehicle when the driving of the vehicle is not handed over from the control by the system to the operation by the driver. Note that the ADC unit 21 may be configured to automatically activate the emergency stop control MRM without relying on the driver's operation when determining that it is necessary to activate the emergency stop control MRM. Further, for example, an emergency stop button or the like may be provided to operate the emergency stop control MRM when an input from the driver is received.

The VDCCU 221 controls the stability of vehicle behavior by having the CPU execute a program stored in the ROM of the controller. In order to stabilize the behavior of the vehicle, the VDC unit 22 includes a wheel speed sensor 222 for detecting the rotational speed of the wheels, a yaw rate sensor (not shown) for detecting the yaw rate of the vehicle, and a rudder for detecting the steering angle of the steered wheels. Various sensors such as an angle sensor (not shown) and a lateral acceleration sensor for detecting lateral acceleration of the vehicle are provided, and detection values detected by these sensors are transmitted to the VDCCU 221 . The VDCCU 221 detects the understeering tendency or oversteering tendency of the vehicle based on the detection values of various sensors, detects the steering angle of the steered wheels and the lateral acceleration of the vehicle, and performs skidding due to braking due to sudden braking or icy road surfaces. is detected to control the brake pressure of each wheel.

The electric parking brake 223 controls the braking state of the wheels and propeller shaft. Based on the command signal from the VDCCU 221, an electric actuator such as a motor is driven to operate and release the parking brake. In this embodiment, an electric parking brake EPKB (Electric Parking Brake) is used as an example of a parking brake. or to control the braking state of the propeller shaft.

The EBACU 231 supports the control of the braking operation by having the CPU execute a program stored in the ROM of the controller. When the EBACU 231 reads the driver's requested braking force from the brake pedal sensor as the sensor 11, the EBACU 231 controls a brake booster (not shown) to reduce the load of the driver's pedaling force using a motor.

The EBACU 231 also controls emergency braking. Based on the output values of various sensors such as a radar for detecting obstacles around the vehicle as the sensor 11, a camera for imaging the surroundings of the vehicle, and a wheel speed sensor 232 for detecting the rotational speed of the wheels, interference with the own vehicle is made. When a possible obstacle such as a vehicle or a stationary object is detected, the EBACU 231 executes emergency brake control based on command values from the ADC unit 21 and the VDC unit 22 . Specifically, if an obstacle that could interfere with the vehicle is detected, the braking action is delayed, or if it is determined that the braking control of the braking action is insufficient, the necessary braking force is secured. Therefore, a command signal for controlling the hydraulic friction brake and the electric parking brake 223 is output.

In this embodiment, the EBA unit 23 is provided separately as a sub-system control unit, but the present invention is not limited to this. For example, the EBA unit 23 may be configured to be incorporated into the ADC unit 21, or may be omitted as necessary. Further, although the VDC unit 22 and the EBA unit 23 are configured to have various sensors separately, for example, the VDC unit 22 and the EBA unit 23 may be configured to share one wheel speed sensor.

The transmission 182 controls a shift state such as shift-up or shift-down based on the setting of the shift position. In the present embodiment, the case of using AT (Automatic Transmission), which automatically shifts gears step by step, is described. The shift state may be controlled using a CVT (Continuously Variable Transmission) for shifting. The shift position has a driving range and a non-driving range. The drive range includes a drive range that is set when the vehicle is traveling forward and a reverse range that is set when the vehicle is traveling in reverse. The non-driving range includes a parking range that is set when the vehicle is stopped and the transmission is fixed. In addition, there is a neutral range that cuts off the transmission of driving force from the drive mechanism to the wheels. ADC unit 21 outputs a command value corresponding to the state of the vehicle, and based on this, transmission 182 sets the shift position and controls the shift state.

As described above, during normal braking control, when the VDC unit 22 receives a command value from the ADC unit 21, the VDC unit 22 and the EBA unit 23 controlled by the VDC unit 22 execute braking control. , the vehicle is decelerated by the hydraulic friction brake, and the electric parking brake 223 is operated to maintain the braking state. However, when an abnormality occurs in the VDC unit 22, for example, when the input signal from the VDCCU 221 is interrupted and the VDC unit 22 cannot be controlled, or when the electric parking brake 223 fails and cannot operate, the braking state of the vehicle is changed. unable to maintain. Therefore, when the ADC unit 21 detects an abnormality in the VDC unit 22, it starts the emergency stop control MRM.

FIG. 5 shows a scene in which emergency stop control MRM is executed by braking control device 20 . When the ADC unit 21 detects the abnormal state of the VDC unit 22 at t1, it notifies the driver of the host vehicle V1 of the abnormal state of the VDC unit 22 at t2. The form of notification of the abnormal state is not particularly limited, but for example, a warning message such as "A system failure has occurred" and a warning message such as "Manual operation Please," or other content that urges the driver to operate may be displayed. In addition to these displays, a warning light may be turned on, or an alarm sound may be emitted to call attention more strongly. It should be noted that notification of an abnormal state to the driver is not an essential component of the present invention, and may be omitted as necessary. In this case, when the ADC unit 21 detects an abnormal state of the VDC unit 22 at t1, it autonomously executes braking control from t3 to t5 without an instruction from the driver.

After notifying the driver of the abnormal state of the VDC unit 22, the ADC unit 21 initiates the emergency stop control MRM when the driver does not respond for a predetermined time. This makes it possible to execute braking control according to urgency. The predetermined time is not particularly limited, but is, for example, 4 seconds, at least until the operation is started by the driver who confirmed the notification of the abnormal state. In addition, the case where no response is obtained includes the case where the response from the driver to the notification of the abnormal state cannot be confirmed, such as when the driver operates the steering wheel or the warning sound is silenced. This is because, in such a case, the driver may be unable to operate the own vehicle V1, and the need for an emergency stop is high.

After starting the emergency stop control MRM, the ADC unit 21 operates the hydraulic friction brake at t3 to start decelerating the host vehicle V1 while maintaining the autonomous travel control function. At this time, the content such as "Emergency stop control will start" may be notified to the presentation device 16 such as a display provided on the instrument panel of the host vehicle V1. By notifying the start of the emergency stop control MRM, it is possible to reduce the driver's anxiety due to the deceleration of the host vehicle V1. Further, when a response such as steering wheel operation by the driver is obtained here, the operation of the emergency stop control MRM may be switched to the operation by the driver. This makes it possible to perform more appropriate braking control during an emergency stop.

After decelerating the vehicle V1 at t3, the ADC unit 21 determines whether the vehicle V1 is stopped at t4. For example, using the wheel speed sensor 222 of the VDC unit 22 and the output value of the output rotary shaft sensor 181, when the output value of the wheel speed or the output value of the output rotary shaft is 0, the vehicle speed is not detected. It is determined that the vehicle is stopped. When determining that the own vehicle V1 is in a stopped state, the ADC unit 21 controls the transmission 182 at t5 to set the shift range to the parking position. Thus, after the output value of the wheel speed or the output value of the output rotary shaft becomes 0, by setting the shift range of the transmission 182 to the parking position without continuing to operate the hydraulic friction brake, the machine can It is possible to reduce the load on the vehicle V1 and maintain the stopped state of the own vehicle V1. The timing for releasing the operation of the hydraulic friction brake may be released at the same time as the shift range is set to the parking position, or may be released after the shift range is set to the parking position.

At t4, when the output value of the wheel speed cannot be detected, such as when the input signal from the VDCCU 221 is interrupted or when the wheel speed sensor 222 is out of order, only the output value of the output rotating shaft is used. may be configured. When the detected value of the wheel output rotary shaft is 0, it means that the vehicle speed is not detected. A stop state of the vehicle V1 can be determined.

Further, as the wheel speed output value, either the output value detected by the wheel speed sensor 222 of the VDC unit 22 or the output value detected by the wheel speed sensor 232 of the EBA unit 23 is used. good too. Thus, even if the main system control unit cannot detect the wheel speed output value, it is possible to use the wheel speed output value of the sub system control unit to determine whether the vehicle V1 is stopped. Further, when the output value of the wheel speed cannot be detected from either the wheel speed sensor 222 of the VDC unit 22 or the wheel speed sensor 232 of the EBA unit 23, the output value of the output rotating shaft sensor 181 should be used. Even if a wide range of abnormalities occur in the braking control device 20, it is possible to appropriately determine whether the vehicle is stopped according to the state of the vehicle V1.

If the shift range is set to the parking position even though the vehicle is not stopped, the components of the transmission 182 may be damaged. Therefore, it is preferable that both the wheel speed output value and the output rotary shaft output value are zero. More preferably, any one of the output value detected by the wheel speed sensor 222 of the VDC unit 22, the output value detected by the wheel speed sensor 232 of the EBA unit 23, and the output value detected by the output rotary shaft sensor 181 When is 0, the reliability of determination of the stopped state is improved.

The estimated time from t3 to t4 may be used to determine whether the host vehicle V1 is stopped at t4. For example, the time required for the vehicle V1 to stop is calculated from the vehicle speed of the vehicle V1 at t1 and the deceleration due to the hydraulic friction brake started at t3. The estimated stop time t4 is set to the calculated time in consideration of the error, and when t4 is reached, the stop state is determined. If the output value of the wheel speed or the output value of the output rotary shaft is detected at the estimated stop time t4 to determine whether the vehicle is stopped, it is not necessary to continuously monitor the output value from the sensor. It is possible to reduce the calculation load at the time. Further, the stop state may be confirmed from the position information of the own vehicle V1 at the estimated stop time t4 using the GPS unit of the own vehicle position detection device 12 or the like. As a result, even if neither the output value of the wheel speed nor the output value of the output rotary shaft can be detected, it is possible to determine the stop state of the host vehicle V1 at the estimated stop time t4. The stopped state of the own vehicle V1 can be appropriately maintained.

<<Brake control processing>>
Next, referring to FIG. 6, the braking control of this embodiment will be described. FIG. 6 is a flowchart showing an example of braking control processing executed by the braking control device 20 of this embodiment. The braking control process described below is executed by the braking control device 20 at predetermined time intervals. In the following description, autonomous speed control and autonomous steering control are executed by the autonomous driving control function of the control device 19 so that the vehicle runs in the lane at the speed set by the driver. It is assumed that lane keep control is being performed to control the traveling position.

First, when an abnormal state of the VDC unit 22 is detected in step S1, the ADC unit 21 outputs a notification to the effect that an abnormal state of the VDC unit 22 has been detected to the passenger in step S2.

Next, in step S3, the ADC unit 21 determines whether or not to start the emergency stop control MRM. If, for example, the driver operates the steering wheel in response to the notification that the VDC unit 22 has detected an abnormal state output in step S2, the braking control process ends without starting the emergency stop control MRM. On the other hand, if no response is obtained for a predetermined time, such as when the driver does not operate the steering wheel, the process proceeds to step S4 and the emergency stop control MRM is started.

At step S5, the ADC unit 21 activates the hydraulic friction brake to start decelerating the host vehicle V1. In subsequent step S6, the ADC unit 21 determines whether or not the vehicle V1 is in a stopped state based on the output values of the wheel speed sensor 222, the wheel speed sensor 232, or the output rotary shaft sensor 181. When the output value of the wheel speed or the output value of the output rotary shaft is 0, it is determined that the host vehicle V1 is in a stopped state, and the process proceeds to step S7. On the other hand, when the output value of the wheel speed or the output value of the output rotation shaft is not 0, step S6 is repeated for a predetermined time.

As a result of the determination in step S6, when it is determined that the host vehicle V1 is in a stopped state, the ADC unit 21 controls the transmission 182 to set the shift range to the parking position in step S7.

As described above, according to the cruise control method and cruise control device 1 of the present embodiment, the signal from the vehicle-mounted braking control device 20 including the hydraulic friction brake and the electric parking brake 223, the wheel speed sensor 222, and the wheel speed sensor 232 , the output value of the wheel speed or the output value of the output rotary shaft detected by the output rotary shaft sensor 181, and the vehicle running control method for executing the braking control by the autonomous running control based on the abnormal state of the braking control device 20. is detected, deceleration of the own vehicle V1 is started, and after the output value of the wheel speed or the output value of the output rotary shaft becomes 0, the shift range of the transmission 182 is changed without using the hydraulic friction brake. to the parking position. As a result, it is possible to reduce the mechanical load during an emergency stop and maintain the vehicle V1 stopped.

Further, according to the cruise control method and the cruise control device 1 of the present embodiment, when the output value of the wheel speed cannot be detected, the shift range of the transmission 182 is set to parking based on the output value of the output rotary shaft. Set to position. Thus, even if the output value of the wheel speed cannot be detected, it is possible to determine whether the vehicle V1 is stopped by using the output value of the output rotary shaft.

Further, according to the cruise control method and cruise control device 1 of the present embodiment, when both the wheel speed output value and the output rotary shaft output value are 0, the shift range of the transmission 182 is set to parking. Since it is set to the position, it is possible to more preferably determine whether the host vehicle V1 is stopped.

Further, according to the cruise control method and cruise control device 1 of the present embodiment, the braking control device 20 includes a first braking control device (VDC unit) 22 and a second braking control device (EBA unit) that backs up the first braking control device (VDC unit) 22. ) 23, and the output value of the wheel speed is the output value detected by the wheel speed sensor 222 provided in the first braking control device (VDC unit) 22, or the output value detected by the second braking control device (EBA unit) 23 is an output value detected by the wheel speed sensor 232 provided in . Thus, even if the main system control unit cannot detect the wheel speed output value, it is possible to use the wheel speed output value of the sub system control unit to determine whether the vehicle V1 is stopped.

Further, according to the cruise control method and cruise control device 1 of the present embodiment, the output value detected by the wheel speed sensor 222 provided in the first braking control device (VDC unit) 22 and the second braking control device ( When none of the output values detected by the wheel speed sensor 232 provided in the EBA unit) 23 is detectable, the shift range of the transmission 182 is set to the parking position based on the output value of the output rotary shaft. . As a result, even when a wide range of abnormalities occur in the braking control device 20, it is possible to appropriately determine whether the vehicle is stopped according to the state of the vehicle V1.

Further, according to the cruise control method and cruise control device 1 of the present embodiment, the output value detected by the wheel speed sensor 222 provided in the first braking control device (VDC unit) 22 and the second braking control (EBA When both the output value detected by the wheel speed sensor 232 provided in the unit 23 and the output value of the output rotary shaft are 0, the shift range of the transmission 182 is set to the parking position, so the vehicle is stopped. The reliability of the determination of is improved.

Further, according to the travel control method and the travel control device 1 of the present embodiment, when an abnormal state of the braking control device 20 is detected, a notification to the effect that an abnormal state has been detected is output to the occupant of the own vehicle V1, Since the emergency stop control is started based on the input from the passenger in response to the notification, the braking control can be executed according to the urgency.

It should be noted that the embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1... Travel control apparatus 11... Sensor 12... Vehicle position detection apparatus 13... Map database 14... Vehicle-mounted apparatus 15... Navigation apparatus 16... Presentation apparatus 17... Input device 18a... Drive control apparatus 18b... Steering control apparatus 19... Control apparatus 20 … Braking control device

Claims (8)

Driving of a vehicle that executes braking control by autonomous driving control based on signals from on-vehicle braking control devices including hydraulic friction brakes and electric parking brakes, and wheel speeds or output values of output rotary shafts detected by sensors. In the control method,
When an abnormal state of the braking control device is detected,
Start decelerating your vehicle,
After the output value of the wheel speed or the output value of the output rotary shaft becomes 0, the vehicle running control method sets the shift range of the transmission to the parking position without using the hydraulic friction brake. 2. The vehicle running control method according to claim 1, wherein, when the output value of the wheel speed cannot be detected, the shift range of the transmission is set to the parking position based on the output value of the output rotary shaft. 3. The vehicle running control according to claim 1, wherein when both the wheel speed output value and the output rotary shaft output value are 0, the shift range of the transmission is set to the parking position. Method. The braking control device is controlled by a first braking control device and a second braking control device that backs up the first braking control device,
The wheel speed output value is an output value detected by a wheel speed sensor provided in the first braking control device or an output value detected by a wheel speed sensor provided in the second braking control device. 4. The vehicle travel control method according to any one of 1 to 3. When neither the output value detected by the wheel speed sensor provided in the first braking control device nor the output value detected by the wheel speed sensor provided in the second braking control device is detectable setting the shift range of the transmission to the parking position based on the output value of the output rotary shaft. An output value detected by the wheel speed sensor provided in the first braking control device, an output value detected by the wheel speed sensor provided in the second braking control device, and an output value of the output rotary shaft 6. The vehicle running control method according to claim 4, wherein when both are 0, the shift range of the transmission is set to the parking position. When an abnormal state of the braking control device is detected,
The vehicle according to any one of claims 1 to 6, wherein a notification to the effect that an abnormal state has been detected is output to the occupant of the own vehicle, and emergency stop control is started based on an input from the occupant in response to the notification. travel control method. Equipped with a processor that executes braking control by autonomous driving control based on a signal from an in-vehicle braking control device including a hydraulic friction brake and an electric parking brake, and the wheel speed or the output value of the output rotary shaft detected by the sensor. In the vehicle running control device with
The processor
When an abnormal state of the braking control device is detected,
Start decelerating your vehicle,
After the output value of the wheel speed or the output value of the output rotary shaft becomes 0, the vehicle travel control device sets the shift range of the transmission to the parking position without using the hydraulic friction brake.

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