JP6638263B2 - Vehicle travel control device and vehicle travel control method - Google Patents

Description

  The present invention relates to a vehicle travel control device and a vehicle travel control method for avoiding a collision or reducing an impact.

  2. Description of the Related Art In recent years, an advanced emergency braking system (AEBS: Advanced Emergency Braking System) that alerts a driver when an approach of a vehicle ahead or the like is detected and activates a brake system of a vehicle for the purpose of avoiding collision or reducing impact has been spreading. . The AEBS issues a warning when approaching the vehicle ahead and prompts the driver to decelerate the vehicle. If the vehicle still approaches the vehicle in front, the AEBS applies relatively weak braking such as engine braking. Apply relatively strong emergency braking such as a foot brake.

  For example, Patent Literature 1 discloses a vehicle that performs such control and reduces an engine output set according to an accelerator opening at a predetermined rate even when a driver depresses an accelerator pedal during automatic braking operation. An automatic brake control device is disclosed.

JP 2015-145139 A

  In the conventional AEBS, when an ABS (Antilock Brake System) is operated during braking and the tires are intermittently locked, the vehicle speed indicated by the speedometer becomes lower than the actual vehicle speed. For this reason, for example, if there is a moving vehicle ahead of the own vehicle in the same direction as the own vehicle and the distance between the own vehicle and the moving vehicle is short, the own vehicle is determined based on the vehicle speed indicated by the speedometer. May be determined to have almost stopped, and the type of the object ahead may be recognized as an oncoming vehicle.

  Thus, even when the type of the forward target changes during braking, it is desired to control the running of the vehicle so as to reduce the risk of colliding with the forward target.

  An object of the present invention is to provide a vehicular travel control device and a vehicular travel control method that can reduce the risk of colliding with a forward target even when the type of the forward target changes during braking.

A traveling control device for a vehicle according to one aspect of the present invention includes a risk calculating unit that calculates a degree of risk of a collision with a forward object existing ahead of the host vehicle, and detects the presence of the forward object. and, second of the vehicle in which the front object is executed when it is determined a detection unit which determines the type indicating whether any objects in any state, and pre-Symbol risk is higher first state 1 control, the second control executed when it is determined that the risk is in the second state higher than the risk in the first state, or in the case where the risk is in the second state. A control unit that determines whether to execute a third control that is performed when it is determined that the third state is higher than the risk level, wherein the control unit is configured to execute the first control. controlled during the execution of a state where the detection unit detects the forward object There, if the type of the front object determined by the detection unit is changed to another type which are not set as the target braking from the predetermined type, stops the first control, the second While performing the control of the third or the third control, in a state where the detection unit has detected the front object, the type of the front object determined by the detection unit is the braking of the predetermined type from the predetermined type When the type is changed to another type not set as the target , the second control or the third control is continued.

The traveling control method for a vehicle according to one aspect of the present invention includes a step of calculating a degree of risk of a collision with a forward object existing in front of the host vehicle, and detecting the presence of the forward object, A step of determining a type indicating what kind of state the forward target object is in, and if the type is a predetermined type, it is executed when it is determined that the risk is high in the first state The first control of the host vehicle, the second control executed when it is determined that the risk is in a second state higher than the risk in the first state, or the risk is Determining whether to execute third control that is performed when it is determined that the vehicle is in the third state that is higher than the risk in the second state. during execution of the control, the detection unit said forward pair A state in which the object was detected, when said type of the front object determined by the detection unit is changed to the predetermined type from the other that is not set as the target braking type, said first control While the second control or the third control is being executed, the detection unit detects the front target object, and the type of the front target object determined by the detection unit is When the type has changed from a predetermined type to another type that is not set as a braking target , the second control or the third control is continued.

  ADVANTAGE OF THE INVENTION According to this invention, even if the type of a front target object changes during braking, a collision with a front target object can be avoided.

1 is a block diagram showing an example of a configuration of a vehicle including a vehicle travel control device according to an embodiment of the present invention. FIG. 4 is a flowchart showing an operation procedure for determining the type of a forward object in the detection unit shown in FIG. 1. Flow chart showing the operation procedure of the vehicle travel control device shown in FIG.

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

(Embodiment)
FIG. 1 is a block diagram showing an example of a configuration of a vehicle 1 including a vehicle travel control device 160 according to an embodiment of the present invention. In the present embodiment, the vehicle 1 is, for example, a large vehicle such as a truck equipped with an in-line six-cylinder diesel engine. Although not shown in detail because it is a well-known configuration, the vehicle 1 includes an engine, a clutch, a transmission (transmission), a propulsion shaft (propeller shaft), a differential device (differential gear), a drive It has a shaft (drive shaft) and wheels. The power of the engine is transmitted to the transmission via the clutch, and the power transmitted to the transmission is transmitted to the wheels via the propulsion shaft, the differential, and the drive shaft. Thus, the power of the engine is transmitted to the wheels, and the vehicle 1 runs.

  As shown in FIG. 1, the vehicle 1 includes a detection unit 120, a speed detection unit 140, a vehicle traveling control device 160, an alarm unit 180, and a braking unit 200.

  The detection unit 120 is a fusion sensor including a vehicle-mounted camera, a millimeter-wave radar, and the like, and detects an object ahead of the vehicle 1. Specifically, the detection unit 120 determines what the front target is from the image of the front target captured by the on-board camera. The detecting unit 120 determines a forward target by pattern matching from an image captured by a vehicle-mounted camera, for example.

  Further, the detection unit 120 detects the reflected wave of the millimeter wave radiated from the millimeter wave radar, calculates the distance between the vehicle 1 and the target ahead, and further calculates the distance between the reflected waves due to the Doppler effect. , The relative speed of the forward object with respect to the vehicle 1 is calculated.

  In addition, the detection unit 120 determines the state of the forward target object based on the determination result of the forward target object, information on the own vehicle speed output from the speed detection unit 140, and information on the relative speed of the forward target object. A type indicating a certain object is determined. This type includes, for example, a moving vehicle, a stopped vehicle, an oncoming vehicle, a moving object other than the vehicle, a stopped object other than the vehicle, an oncoming object other than the vehicle, and the like. Note that the detection unit 120 repeatedly performs the type determination of the forward target object.

  Further, when the type determined this time has changed from the type determined last time, the detection unit 120 outputs information on the type determined this time.

  The detection unit 120 transmits the information on the relative distance between the vehicle 1 and the front target, the information on the relative speed, and the type information on the front target to the vehicle travel control device 160 (the collision allowance time calculation unit 162, the control unit 163 and the target deceleration calculation unit 166).

  The speed detection unit 140 acquires wheel rotation information (not shown) from a rotation sensor (not shown), calculates the speed of the vehicle 1 based on the wheel rotation information, and outputs the information on the speed to the detection unit 120 and the brake control unit 168. Output to

  The vehicle travel control device 160 automatically controls the braking amount of the vehicle 1 separately from a braking instruction by a brake pedal (not shown). In the vehicle travel control device 160, alarm control, alarm brake control, and emergency brake control are set as three types of braking control having different braking levels.

  The warning control is the control with the lowest braking level that is executed first when the vehicle travel control device 160 determines that there is a possibility of collision with the forward object. In the alarm control, the driver is prompted to perform a collision avoidance operation including a brake operation (braking operation) by outputting an alarm sound or alerting the front target by a meter display or the like.

  The alarm brake control is a control that is executed when an appropriate collision avoidance operation (such as steering or brake operation by the driver) is not performed by the driver with respect to the alarm control. In the alarm brake control, relatively weak automatic braking (braking) intervention is performed, and the automatic brake reminds the driver again.

  The emergency brake control is a control having the highest braking level that is executed when the driver has not yet performed an appropriate collision avoidance operation with respect to the alarm brake control. In the emergency brake control, a strong automatic brake (braking) intervention is performed, and the collision between the vehicle 1 and the forward object is avoided by the automatic brake.

  As shown in FIG. 1, the vehicle travel control device 160 includes a collision margin time calculation unit 162, a control unit 163, and a target deceleration calculation unit 166. The control unit 163 includes an alarm control unit 164 and a braking control unit 168.

  The collision margin time calculation unit 162 (corresponding to a risk calculation unit) can cause the vehicle 1 to collide with the front object based on the distance and the relative speed between the vehicle 1 and the front object output from the detection unit 120. It is determined whether or not the state is before collision occurrence with high possibility. Specifically, the time to collision calculation unit 162 calculates a time to collision (hereinafter, referred to as “TTC (Time To Collision)”) by dividing the distance between the vehicle 1 and the forward object by the relative speed. .

  When the value of the calculated TTC is, for example, less than 3.0 [sec] and equal to or more than 1.8 [sec], the collision margin time calculation unit 162 has a high possibility that the vehicle 1 collides with the forward object. It is determined that the current state is the first state before the occurrence of the collision (in other words, the state where the execution of the alarm control is necessary), and notifies the alarm control unit 164 of the fact. When the value of TTC is, for example, less than 1.8 [sec] and 0.6 [sec] or more, the collision margin time calculation unit 162 determines that there is a possibility that the vehicle 1 will collide with the front target. It is determined that the second pre-collision state is higher than the first pre-collision state (in other words, the state in which the execution of the alarm brake control is required), and the alarm control unit 164 and the target deceleration calculation unit 166 are determined to that effect. Notify. When the TTC value is, for example, less than 0.6 [sec], the collision margin time calculation unit 162 determines that the possibility that the vehicle 1 will collide with the forward target is higher than the second collision pre-occurrence state. It is determined that the state before the occurrence of the collision of No. 3 (in other words, the state in which the execution of the emergency brake control is necessary), and the fact is notified to the alarm control unit 164 and the target deceleration calculation unit 166.

  The control unit 163 controls the alarm control unit 164 and the brake control unit 168 when the type information of the forward target output from the detection unit 120 is a predetermined type. For example, when the type information of the forward target output from the detection unit 120 is a moving vehicle or a stopped vehicle, the control unit 163 starts the control of the alarm control unit 164 and the braking control unit 168.

  When the alarm control unit 164 receives a notification indicating that it is determined that the vehicle is in the first pre-collision state from the collision margin time calculation unit 162, the alarm control unit 164 outputs an alarm output command to the alarm unit 180, and outputs the vehicle 1 and the object ahead. Then, an alarm (for example, a meter display or a speaker sound) for notifying the driver that the possibility of collision with the vehicle is in a state before the occurrence of the first collision is generated. In addition, when receiving a notification from the collision margin time calculation unit 162 that the control unit 164 has determined that the vehicle is in the second pre-collision state, the warning control unit 164 outputs a warning output command to the warning unit 180 and communicates with the vehicle 1 in front of the vehicle 1. An alarm is generated for notifying the driver that the possibility of collision with the target is the second pre-collision state. Further, when receiving a notification from the collision margin time calculation unit 162 that the alarm control unit 164 has determined that the vehicle is in the third pre-collision state, the alarm control unit 164 outputs an alarm output command to the alarm unit 180 and communicates with the vehicle 1 in front of the vehicle 1. An alarm for notifying the driver that the possibility of collision with the object is the third pre-collision state is generated. The driver may be informed that the possibility of collision between the vehicle 1 and the forward object is high by causing a light emitting device such as a lamp to emit light instead of the meter display or the speaker sound.

  When the target deceleration calculation unit 166 receives a notification indicating that it is determined that the vehicle is in the second pre-collision occurrence state from the collision margin time calculation unit 162, the target deceleration calculation unit 166 needs to alert the driver of the collision avoidance operation. A target deceleration (hereinafter, “first target deceleration”) is output to the braking control unit 168. In addition, when the target deceleration calculation unit 166 receives a notification indicating that the vehicle is in the third pre-collision state from the collision margin time calculation unit 162, the target deceleration calculation unit 166 determines the target necessary for avoiding collision between the vehicle 1 and the front target. The deceleration (hereinafter, “second target deceleration”) is calculated and output to the braking control unit 168.

  The brake control unit 168 is, for example, a brake control device such as an EBS (Electronic Braking System). When the first target deceleration is output from the target deceleration calculation unit 166, the braking control unit 168 calculates the actual deceleration of the vehicle 1 obtained by differentiating the speed output from the speed detection unit 140 by a predetermined time. Controls the braking unit 200 such that the first target deceleration is generated, and generates a first braking force (warning brake) for the vehicle 1 such as an engine brake. In addition, when the second target deceleration is output from the target deceleration calculation unit 166, the braking control unit 168 controls the braking unit 200 so that the actual deceleration of the vehicle 1 becomes the second target deceleration. A second braking force (emergency braking) larger than the first braking force is generated for the first braking force.

  Here, during execution of the alarm control of the alarm control unit 164 and the alarm brake control of the brake control unit 168, the control unit 163 determines whether the type of the forward object is the target of three types of braking control with different braking levels. When the type (moving vehicle or stopped vehicle) is changed to another type such as an oncoming vehicle that is not set as the target of the braking control, the alarm control of the alarm control unit 164 is stopped. On the other hand, while the brake control unit 168 is executing the alarm brake control or the emergency brake control, the control unit 163 sets the type of the forward object from a predetermined type (moving vehicle or stopped vehicle) as the target of the brake control. When the type is changed to another type such as an oncoming vehicle, the warning brake control or the emergency brake control of the brake control unit 168 is continued.

  The warning unit 180 acquires a warning output command from the vehicle travel control device 160 (warning control unit 164). The warning unit 180 outputs a warning when the warning output command is acquired. The alarm unit 180 may output an alarm by sounding a speaker, or may output an alarm by causing a light emitting device such as a lamp to emit light.

  The braking unit 200 is, for example, a foot brake that applies a resistance to the wheels of the vehicle 1, and applies a braking force to the vehicle 1 under the control of the braking control unit 168. The braking unit 200 is not limited to a foot brake as long as it generates a braking force on the vehicle 1. For example, the braking unit 200 may be an auxiliary brake such as a retarder that applies resistance to a propulsion shaft (propeller shaft) or an exhaust brake that applies a load to an engine.

  The vehicle travel control device 160 includes a CPU (Central Processing Unit) or a computing device such as a microcomputer (not shown), a ROM (Read Only Memory), a hard disk, an SSD (Solid State Drive), and a RAM (Random Access Memory). The computing device includes a storage device and an input / output circuit, and a program preset in the storage device is executed by the arithmetic device to realize the function of the program.

  Next, the determination of the type of the forward target object by the above-described detection unit 120 will be described. FIG. 2 is a flowchart showing an operation procedure for determining the type of the forward object in the detection unit 120 shown in FIG.

  In step S201, the detection unit 120 detects an object in front of the vehicle 1 using a millimeter-wave radar, and detects what the front target is from an image captured by a vehicle-mounted camera.

  In step S202, the detection unit 120 calculates a distance (distance information) between the vehicle 1 and the target ahead based on the detection information of the millimeter wave radar.

  In step S203, the detection unit 120 acquires the speed of the own vehicle from the speed detection unit 140, and in step S204, the detection unit 120 determines, based on the change in the frequency generated in the reflected wave due to the Doppler effect, the target object ahead of the vehicle 1 The relative speed is calculated, and the speed of the forward object is calculated based on the calculated relative speed and the speed of the host vehicle.

  In step S205, the detection unit 120 determines the type of the forward target based on the detection result of the forward target in step S201 and the speed of the forward target in step S204.

  In step S206, the detection unit 120 determines whether or not the front object has disappeared. If the front object has not disappeared (NO), the process returns to step S201, and if the front object has disappeared (YES). The detection unit 120 ends the type determination of the forward target object.

  As described above, the type determination of the forward target object is repeatedly performed while the detection unit 120 is energized.

  Next, the operation of the above-described vehicle travel control device 160 will be described. FIG. 3 is a flowchart showing an operation procedure of vehicle running control device 160 shown in FIG.

  In step S301, the time to collision calculation unit 162 calculates the TTC for the forward object, and in step S302, the time to collision calculation unit 162 determines that the TTC calculated in step S301 is less than the first threshold Th1. Further, it is determined whether or not it is equal to or more than a predetermined second threshold. If the TTC is less than the first threshold Th1 and equal to or greater than the second threshold (YES), the process proceeds to step S303. If the TTC is not less than the first threshold Th1 and is not equal to or greater than the second threshold (NO), the process proceeds to step S304. The first threshold value Th1 is, for example, 3.0 [seconds], and the second threshold value Th2 is, for example, 1.8 [seconds].

  In step S303, the warning control unit 164 issues a warning output command to the warning unit 180, and in step S304, the control unit 163 determines whether the type of the forward object output from the detection unit 120 is a warning control and an automatic brake control. It is determined whether or not the type has changed from a predetermined type (moving vehicle or stopped vehicle) to an oncoming vehicle. If the type has changed to an oncoming vehicle (YES), the process proceeds to step S305, and the type changes to an oncoming vehicle. If it has not changed (NO), the process moves to step S306.

  In step S305, the warning control unit 164 issues a warning output stop command to the warning unit 180, and proceeds to step S312.

  In step S306, the time to collision calculation unit 162 determines whether the TTC calculated in step S301 is less than the second threshold Th2 and not less than a third threshold. When TTC is less than the second threshold Th2 and is equal to or more than the third threshold (YES), the process proceeds to step S307, and when TTC is less than the second threshold Th2 and is not equal to or more than the third threshold (NO) ), And proceed to step S308. The third threshold value Th2 is, for example, 0.6 [second].

  In step S307, the brake control unit 168 determines to execute the alarm brake control, and instructs the brake unit 200 to execute the alarm brake control.

  In step S308, the control unit 163 determines that the alarm brake control is to be executed without stopping even if the type is changed during the alarm brake control, and instructs the brake unit 200 via the brake control unit 168 to execute the alarm brake control. To instruct.

  In step S309, the time to collision calculation unit 162 determines whether the TTC calculated in step S301 is less than a predetermined third threshold Th3. If the TTC is less than the third threshold Th3 (YES), the process proceeds to step S310, and if the TTC is equal to or greater than the third threshold Th3 (NO), the process proceeds to step S312.

  In step S310, the braking control unit 168 determines that the emergency braking control is to be performed, and instructs the braking unit 200 to perform the emergency braking control.

  In step S311, the control unit 163 determines that the emergency brake control is to be executed without stopping even if the type is changed during the emergency brake control, and the control unit 163 sends the execution to the braking unit 200 via the brake control unit 168. To instruct.

  In step S312, the control unit 163 determines whether the forward object has disappeared. If the forward object has disappeared (YES), the operation of the vehicle travel control device 160 ends, and the forward object disappears. If not (NO), the process returns to step S301.

  As described above, according to the present embodiment, the wheels lock intermittently during the automatic brake braking, and the speed information of the vehicle 1 detected by the speed detection unit 140 becomes smaller than the actual speed. Even if the type is changed during the automatic brake braking, the collision with the object ahead can be avoided by continuing without releasing the automatic brake.

  In the present embodiment, the warning brake for relatively weak braking is realized by the engine brake, and the emergency braking for strong braking is realized by the foot brake, but the present invention is not limited to this. For example, the warning brake may be realized by a foot brake or an auxiliary brake, and the emergency brake may be realized by combining an engine brake, a foot brake, and an auxiliary brake.

  INDUSTRIAL APPLICABILITY The present invention is useful for avoiding a collision with a forward object even when the type of the forward object changes during emergency braking.

Reference Signs List 1 vehicle 120 detection unit 140 speed detection unit 160 vehicle travel control device 162 collision margin time calculation unit 163 control unit 164 alarm control unit 166 target deceleration calculation unit 168 braking control unit 180 alarm unit 200 braking unit

Claims (4)

A risk calculating unit that calculates the degree of risk for a collision with a forward object existing ahead of the vehicle,
A detection unit that detects the presence of the forward target and determines a type indicating what state the forward target is in,
First control of the vehicle to be executed when it is determined that the previous SL risk in higher first state, to a higher second state than risk in the risk that the first state The second control that is executed when it is determined that there is, or the third control that is executed when it is determined that the risk is in a third state that is higher than the risk in the second state A control unit that determines whether to execute control,
With
The control unit is in a state where the detection unit has detected the front target object during the execution of the first control, and the type of the front target object determined by the detection unit is different from the predetermined type. When changing to another type that is not set as a target of braking, the first control is stopped, and while the second control or the third control is being performed, the detection unit detects the forward target object. In the detection state, when the type of the forward target object determined by the detection unit changes from the predetermined type to another type that is not set as a braking target , the second control or the second control Continue the control of 3.
Travel control device for vehicles. The first control is an alarm output control.
The vehicle travel control device according to claim 1. The second control is a braking control of the host vehicle, and a braking force in the second control is weaker than a braking force in the third control.
The vehicle travel control device according to claim 1. Calculating a high degree of risk for a collision with a forward object existing in front of the host vehicle;
Detecting the presence of the front target, and determining a type indicating what state the front target is in,
First control of the vehicle to be executed when it is determined that the previous SL risk in higher first state, to a higher second state than risk in the risk that the first state The second control that is executed when it is determined that there is, or the third control that is executed when it is determined that the risk is in a third state that is higher than the risk in the second state Determining whether to execute the control,
With
While the first control is being executed, the detection unit detects the front object, and the type of the front object determined by the detection unit is set as the braking target from the predetermined type. If the type has been changed to another type that has not been performed , the first control is stopped, and the state is such that the detection unit has detected the forward target object while the second control or the third control is being executed. When the type of the forward object determined by the detection unit changes from the predetermined type to another type that is not set as a braking target , the second control or the third control is continued. Let
A traveling control method for a vehicle.

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