JP6119476B2 - Convoy travel control device and convoy travel control method - Google Patents

Description

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

  In the prior art described in Patent Document 1, when carrying out platooning, an identification number ID is assigned in order from the leading vehicle via inter-vehicle communication, and the running of each vehicle is controlled according to the assigned identification number ID. And it is proposed to make the following vehicle follow the leading vehicle.

Japanese Patent Laid-Open No. 9-81899

When following the preceding vehicle as a platooning, it is conceivable to control the acceleration / deceleration of the own vehicle according to the inter-vehicle time, for example. However, if the preceding vehicle is merely tracked according to the inter-vehicle time, there is a possibility that the platooning may be disturbed, for example, because the time difference from when the preceding vehicle decelerates until the own vehicle decelerates increases.
An object of the present invention is to maintain good row running by decelerating at a more appropriate timing when following a preceding vehicle.

  The convoy travel control apparatus according to one aspect of the present invention is configured to form a convoy with a plurality of vehicles on the same lane, set a target inter-vehicle time for a preceding vehicle, and realize the target inter-vehicle time. The inter-vehicle time control for controlling the acceleration / deceleration of the host vehicle is made executable. On the other hand, the deceleration state of the preceding vehicle is detected, the inter-vehicle distance from the preceding vehicle is detected, the inter-vehicle distance when the preceding vehicle starts decelerating is set as the target inter-vehicle distance, and this target inter-vehicle distance is To achieve this, inter-vehicle distance control for controlling the acceleration / deceleration of the host vehicle is made executable. Further, the host vehicle speed is detected, the inter-vehicle time for the preceding vehicle is detected according to the own-vehicle speed and the inter-vehicle distance, and the inter-vehicle time control is performed when the inter-vehicle time maintains the target inter-vehicle time. Further, a predetermined lower limit threshold is set in a range smaller than the target inter-vehicle time, and a range from the target inter-vehicle time to the lower limit threshold is set as a dead zone for maintaining the inter-vehicle time control. When the inter-vehicle time control is performed and the inter-vehicle time falls below the lower limit threshold, the inter-vehicle time control is switched to the inter-vehicle distance control.

  According to the present invention, in a situation where the target inter-vehicle time can be maintained, the inter-vehicle time control is executed. For example, even if the preceding vehicle decelerates and the inter-vehicle time falls below the target inter-vehicle time, the target inter-vehicle time Is maintained within the range from to the lower threshold. In a situation where the inter-vehicle time is below the lower threshold, the inter-vehicle time control is switched to the inter-vehicle distance control. In this way, instead of responding only by inter-vehicle time control, by executing inter-vehicle distance control as necessary, the vehicle following the preceding vehicle can be decelerated at a more appropriate timing, and good platooning can be maintained. can do.

It is a schematic block diagram which shows a convoy travel control apparatus. It is a flowchart which shows a convoy travel control process. It is a flowchart which shows the control switching judgment process of 1st Embodiment. It is a figure explaining disorder of vehicle speed in platooning. It is a figure explaining disorder of the inter-vehicle time in platooning. It is a time chart which shows operation | movement of 1st Embodiment. It is a flowchart which shows the control switching judgment process of 2nd Embodiment. It is a time chart which shows operation | movement of 2nd Embodiment. It is a flowchart which shows the control switching judgment process of 3rd Embodiment. It is a time chart which shows operation | movement of 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<< First Embodiment >>
"Constitution"
ACC (Adaptive Cruise Control) and CACC (Cooperative Adaptive Cruise Control) are technologies that control the running of the vehicle according to the relative relationship with the preceding vehicle in order to run in a row with multiple vehicles on the same lane. ) Etc. First, ACC is a system that uses a radar mounted in front of a vehicle to maintain a constant distance between the vehicle traveling ahead and warns the driver as necessary. On the other hand, CACC is a system that performs more precise travel control by sharing acceleration / deceleration information of other vehicles through inter-vehicle communication, and travels at a shorter inter-vehicle distance than ACC and hunting (inter-vehicle) Stable running with less fluctuation is possible. In the present embodiment, a description will be given of a convoy travel using CACC as an example.

In the present embodiment, all the vehicles that travel on the same lane and control the traveling of the host vehicle according to the relative relationship with the preceding vehicle are referred to as a platoon. In this platoon, for example, a vehicle group is formed by about 3 to 5 vehicles, and the inter-vehicle distance between the vehicle groups is made wider than the inter-vehicle distance between the vehicles in the vehicle group. In addition, when a preceding vehicle does not exist in front of the host vehicle, a predetermined set vehicle speed is maintained.
FIG. 1 is a schematic configuration diagram showing a row running control device.
The convoy travel control apparatus according to the present embodiment includes a CACC switch 11, a wheel speed sensor 12, a surrounding situation recognition device 13, a communication device 14, a navigation system 15, and a controller 16.

  The CACC switch 11 includes a group of switches such as a main switch, a cancel switch, a resume / accelerate switch, a set / coast switch, an inter-vehicle time setting switch, and the like. It is provided. The main switch switches on / off of CACC, and the cancel switch temporarily cancels the setting of CACC. The resume / accelerate switch restores the temporarily released CACC, or increases the set vehicle speed in increments of 5 km / h, for example. The set / coast switch sets the current vehicle speed as the set vehicle speed, or decreases the set vehicle speed in increments of 5 km / h, for example. The inter-vehicle time setting switch switches the target inter-vehicle time Tt to, for example, three stages of long, medium, and short each time the switch is pressed. These CACC switches 11 output voltage signals corresponding to various operation situations to the controller 16. The controller 16 determines various operation situations from the input voltage signal.

  Note that the target inter-vehicle time for the preceding vehicle needs to be different depending on whether the host vehicle is a succeeding vehicle excluding the leading vehicle in the vehicle group or a leading vehicle in the vehicle group. For example, if the target inter-vehicle time for the following vehicle is about 0.7 sec, it is desirable to set the target inter-vehicle time for the leading vehicle to about 1.8 sec. Therefore, it may be configured such that both the target inter-vehicle time for the following vehicle and the target inter-vehicle time for the leading vehicle can be individually set by operating the inter-vehicle time setting switch. In addition, when one of the target inter-vehicle time for the following vehicle and the target inter-vehicle time for the leading vehicle is set by operating the inter-vehicle time setting switch, the other is set by adding or subtracting a predetermined inter-vehicle time. It is good also as a structure to be made.

The wheel speed sensor 12 detects the wheel speeds Vw _{FL to} Vw _RR of each wheel. The wheel speed sensor 12 includes, for example, a sensor rotor that rotates together with a wheel and has a protrusion (gear pulser) formed on a circumference thereof, and a detection circuit that includes a pickup coil provided to face the protrusion of the sensor rotor. Prepare. Then, the change in magnetic flux density accompanying the rotation of the sensor rotor is converted into a voltage signal by the pickup coil and output to the controller 16. The controller 16 determines the wheel speeds Vw _{FL to} Vw _RR from the input voltage signal, and calculates, for example, the wheel speed average value of the non-driven wheels (driven wheels) or the wheel speed average value of all the wheels as the vehicle speed.

The surrounding situation recognition device 13 includes a radar device and a stereo camera, and recognizes the situation in front of the host vehicle.
The radar apparatus detects a distance to a front object existing in front of the host vehicle, a relative speed, and a direction. This radar apparatus is composed of a millimeter wave radar provided in the front grill, and outputs various detected data to the controller 16. For distance and relative speed, for example, FM-CW (Frequency Modulation-Continuous Wave) is used, and distance and relative speed are detected according to the frequency difference due to the Doppler effect, and for direction, for example, DBF (Digital Beam Forming) Using the method, the azimuth is detected according to the phase difference of the reflected waves received by a plurality of channels.

  The stereo camera images the front of the vehicle body. This stereo camera is composed of two cameras having the same specifications, is arranged along the vehicle width direction at the upper part of the front window in the vehicle interior, and has an optical axis and camera coordinates in parallel. Image data in front of the vehicle body captured by the stereo camera is input to the image processing apparatus and subjected to stereo image processing. That is, a distance distribution image is generated over the entire screen area from the parallax between the left camera image and the right camera image, and based on this distance distribution image and the original image, the position of the front object and the traveling division line (white line) are detected. The detected various data are output to the controller 16.

  The communication device 14 transmits / receives information for convoy management to / from vehicles in the vehicle group and other vehicles that are to join the vehicle group via inter-vehicle communication. Information for convoy management includes the ID number of the host vehicle, the current position of the host vehicle, the inter-vehicle distance with the preceding vehicle, the relative vehicle speed with the preceding vehicle, the host vehicle speed, acceleration / deceleration, brake signal, accelerator signal, blinker signal, These are operation signals and abnormal signals of various control systems. The operation signals of various control systems include the operation state of CACC and the operation state of CC (Cruise Control). The CC is a system that controls the acceleration / deceleration of the host vehicle in order to maintain a predetermined vehicle speed.

  For vehicle-to-vehicle communication, radio wave communication or optical communication is used. In radio communication, for example, a frequency band of 5.8 GHz band or 700 MHz band is used, and communication is performed by an orthogonal frequency division multiplexing (OFDM). Note that communication errors are reduced between the first vehicle and the last vehicle in the vehicle group by performing multi-hop communication (ad hoc communication) that communicates indirectly via a relay vehicle rather than directly communicating. Communication quality can be improved. In optical communication, for example, near infrared light of about 880 nm is used, and communication is performed by frequency shift keying (FSK) or amplitude shift keying (ASK).

  The navigation system 15 recognizes the current position of the host vehicle and road map information at the current position. This navigation system 15 has a GPS receiver, and recognizes the position (latitude, longitude, altitude) of the host vehicle and the traveling direction based on the time difference between radio waves arriving from four or more GPS satellites. The controller refers to the road map information including the road type, road alignment, lane width, vehicle traffic direction, etc. stored in the DVD-ROM drive or hard disk drive, and recognizes the road map information at the current position of the host vehicle. 16 is output. In addition, as a safe driving support system (DSSS: Driving Safety Support Systems), various data may be received from an infrastructure using two-way radio communication (DSRC: Dedicated Short Range Communication).

The controller 16 is composed of, for example, a microcomputer, and executes a row running control process, which will be described later, based on detection signals from each sensor, and drives and controls the driving force control device 20 and the brake control device 50.
The driving force control device 20 controls the driving force of the rotational driving source. For example, if the rotational drive source is an engine, the engine output (the number of revolutions and the engine torque) is controlled by adjusting the opening of the throttle valve, the fuel injection amount, the ignition timing, and the like. If the rotational drive source is a motor, the motor output (number of revolutions and motor torque) is controlled via an inverter.

Next, the brake control device 50 will be described.
The brake control device 50 controls the braking force of each wheel. For example, the hydraulic pressure of a wheel cylinder provided in each wheel is controlled by a brake actuator used for anti-skid control (ABS), traction control (TCS), stability control (VDC: Vehicle Dynamics Control), and the like.

Next, the row running control process executed by the controller 16 every predetermined time (for example, 10 msec) will be described.
Here, it is assumed that only the vehicle group to which the host vehicle belongs exists, and this will be referred to as a formation for convenience.
FIG. 2 is a flowchart showing the row running control process.
First, in step S101, various data are read.
In the subsequent step S102, for example, the average wheel speed of the non-driven wheels (driven wheels) is calculated as the own vehicle speed Vs.

In the subsequent step S103, the target inter-vehicle time Tt is set depending on whether the host vehicle is the leading vehicle or the following vehicle in the platoon, that is, whether the ID number is # 1 or other than that. . Specifically, when the host vehicle is the leading vehicle, the target inter-vehicle time Tt _H for the leading vehicle set by the inter-vehicle time setting switch is set as the target inter-vehicle time Tt. On the other hand, when the host vehicle is a subsequent vehicle, the target inter-vehicle time Tt _F for the subsequent vehicle set by the inter-vehicle time setting switch is set as the target inter-vehicle time Tt.
In the subsequent step S104, the first target inter-vehicle distance Dt1 for realizing the target inter-vehicle time Tt is calculated according to the target inter-vehicle time Tt and the vehicle speed Va of the preceding vehicle, as shown in the following equation. The vehicle speed Va of the preceding vehicle is calculated by the difference between the relative speed Vr with the preceding vehicle and the host vehicle speed Vs.
Dt1 = Va × Tt

In subsequent step S105, a target vehicle speed Vt for realizing the first target inter-vehicle distance Dt1 is calculated.
First, as shown in the following formula, according to the vehicle speed Va of the preceding vehicle, the deviation ΔD (= Dt1−Dr) between the first target inter-vehicle distance Dt1 and the inter-vehicle distance Dr, and the relative speed Vr with respect to the preceding vehicle, The basic target vehicle speed Vb is calculated. Here, K1 is a gain to be multiplied by Va, K2 is a gain to be multiplied by ΔD, K3 is a gain to be multiplied by Vr, and f {} is in accordance with K1 × Va, K2 × ΔD, and K3 × Vr. A function for calculating the basic target vehicle speed Vb is shown.
Vb = f {K1 × Va, K2 × ΔD, K3 × Vr}
Then, as shown in the following mathematical formula, the final target vehicle speed Vt is calculated by subjecting the reference target vehicle speed Vb to a first-order lag filter process according to a predetermined transfer characteristic.

In subsequent step S106, a target acceleration / deceleration Gt for realizing the target vehicle speed Vt is calculated according to the own vehicle speed Vs and the target vehicle speed Vt, as shown in the following formula, according to a predetermined response characteristic. Here, f {} represents a function for calculating the target acceleration / deceleration Gt according to Vs and Vt. When the host vehicle speed Vs is higher than the target vehicle speed Vt, the target acceleration / deceleration Gt is a negative deceleration value. When the host vehicle speed Vs is lower than the target vehicle speed Vt, the target acceleration / deceleration Gt is a positive acceleration value. .
Gt = f {Vs, Vt}

In subsequent step S107, a rate limiter process is performed on the target acceleration / deceleration Gt. That is, when the change amount per unit time of the target acceleration / deceleration Gt, here, the change amount ΔGt from the previous value Gt _(n−1) is equal to or less than a predetermined upper limit value ΔG1, the target acceleration / deceleration Gt is maintained as it is. . On the other hand, when the change amount ΔGt from the previous value Gt _(n−1) is larger than the upper limit value ΔG1, the target acceleration / deceleration is performed so that the change amount ΔGt from the previous value Gt _(n−1) becomes the upper limit value ΔG1. Gt is corrected and the rate of change is limited.

In subsequent step S108, as shown in the following equation, as the inter-vehicle time control, a first acceleration / deceleration command value Gc1 for realizing the target acceleration / deceleration Gt is calculated according to the target acceleration / deceleration Gt. Here, Ts is a predetermined set time, and f {} represents a function for calculating the first control command value Gc1 according to Gt. The first acceleration / deceleration command value Gc1 is a positive value when it is an acceleration command, and is a negative value when it is a deceleration command.
Gc1 = f {Gt} × Ts

  In subsequent step S109, the traveling state of the preceding vehicle is determined. Here, the start of deceleration of the preceding vehicle is determined by inter-vehicle communication with the preceding vehicle via the communication device 14. Whether or not the preceding vehicle starts decelerating is determined from a decelerating operation such as when the brake switch is switched from OFF to ON or the transmission is shifted down. The deceleration operation is not only input by the driver, but also input by the actuator when performing accelerator control or brake control, such as performing control intervention to avoid contact with an obstacle or driving automatically. Including.

In the following step S110, as the inter-vehicle distance control, the inter-vehicle distance Dr with the preceding vehicle at the time when the start of deceleration of the preceding vehicle is detected is set as the second target inter-vehicle distance Dt2, and the second target inter-vehicle distance Dt2 Is set to a second acceleration / deceleration command value Gc2. The second acceleration / deceleration command value Gc2 is a set value for generating a deceleration according to a deviation ΔD between the second target inter-vehicle distance Dt2 and the inter-vehicle distance Dr, and is a negative value because it is a deceleration command. . Alternatively, a fixed value that generates a predetermined deceleration may be used, or a fixed value and a select high value of a set value may be used.
In the subsequent step S111, a control switching determination process described later is executed, and either one of the inter-vehicle time control or the inter-vehicle distance control is selected, and a final deceleration command value Gc is set.

In the subsequent step S112, an engine torque command value and a brake fluid pressure command value as control command values are set according to realization of the final deceleration command value Gc. When the deceleration command value Gc is an acceleration command, the engine torque command value is increased and the brake fluid pressure command value is set to zero. When the deceleration command value Gc is a deceleration command, the engine torque command value is set to 0 and the brake fluid pressure command value is increased.
In the subsequent step S113, the driving force control device 20 is driven and controlled according to the engine torque command value, and the brake control device 50 is driven and controlled according to the brake fluid pressure command value, and then returns to a predetermined main program.
The above is the row running control process of this embodiment.

Next, the control switching determination process will be described.
FIG. 3 is a flowchart showing the control switching determination process.
First, in step S121, the traveling state of the preceding vehicle is determined. Here, the end of deceleration of the preceding vehicle is determined by inter-vehicle communication with the preceding vehicle via the communication device 14. Whether or not the preceding vehicle finishes decelerating is determined from a decelerating end operation such as, for example, switching the brake switch from ON to OFF or shifting up the transmission. Note that the deceleration end operation is not only input by the driver, but also an actuator when performing accelerator control or brake operation, such as ending control intervention for avoiding contact with an obstacle or automatically driving Also includes input by.

In the following step S122, an inter-vehicle time THW (Time Headway) for the preceding vehicle is calculated, and it is determined whether or not the inter-vehicle time THW is shorter than a predetermined lower threshold Tth _MIN .
Here, the inter-vehicle time THW is a value obtained by dividing the inter-vehicle distance Dr with the preceding vehicle by the own vehicle speed Vs, as shown in the following equation.
THW = Dr / Vs
Further, the lower limit threshold value Tth _MIN is a value obtained by subtracting a predetermined margin Tm from the target inter-vehicle time Tt set by the inter-vehicle time setting switch, as shown in the following equation. The margin Tm is, for example, about 0.1 [sec]. Therefore, when the target inter-vehicle time Tt is, for example, 0.7 [sec], the lower limit threshold value Tth _MIN is about 0.6 [sec].
Tth _MIN = Tt-Tm
Here, when the inter-vehicle time THW is equal to or greater than the lower limit threshold value Tth _MIN, it is determined that there is almost no tendency to approach the preceding vehicle, and the process proceeds to step S123. On the other hand, when the determination result shows that the inter-vehicle time THW is shorter than the lower limit threshold value Tth _MIN , it is determined that the vehicle tends to approach the preceding vehicle, and the process proceeds to step S125.

In a succeeding step S123, it is determined whether or not the inter-vehicle distance control flag is set to ft = 1. The inter-vehicle distance control flag is a flag that indicates whether the inter-vehicle distance control is executed with priority over the inter-vehicle time control. That is, when ft = 0, it means that the inter-vehicle distance control is not executed, that is, when the inter-vehicle time control is executed, and when ft = 1, this means that the inter-vehicle distance control is executed with priority over the inter-vehicle time control. In the initial state, the inter-vehicle distance control flag is reset to ft = 0. Here, when the determination result is ft = 0, it is determined that the inter-vehicle time control is being executed, and the process proceeds to step S124. On the other hand, when the determination result is ft = 1, it is determined that the inter-vehicle distance control is being executed, and the process proceeds to step S131.
In the subsequent step S124, as the inter-vehicle time control, the first acceleration / deceleration command value Gc1 is set to the final acceleration / deceleration command value Gc, and then the routine returns to a predetermined main program.

In step S125, it is determined whether the inter-vehicle distance control flag is reset to ft = 0. Here, when the determination result is ft = 0, it is determined that the inter-vehicle time control is being executed, and the process proceeds to step S126. On the other hand, when the determination result is ft = 1, it is determined that the inter-vehicle distance control is being executed, and the process proceeds to step S128.
In step S126, in order to switch from inter-vehicle time control to inter-vehicle distance control, the inter-vehicle distance control flag is set to ft = 1.
In the following step S127, as the inter-vehicle distance control, the second acceleration / deceleration command value Gc2 is set to the final acceleration / deceleration command value Gc, and then the routine returns to a predetermined main program.

In step S128, it is determined whether the preceding vehicle has finished decelerating. Here, when the preceding vehicle has finished decelerating, it is determined that the approaching tendency to the preceding vehicle can be suppressed even if the inter-vehicle distance control is returned to the inter-vehicle time control, and the process proceeds to step S129. On the other hand, when the preceding vehicle has not finished decelerating, it is determined that unless the inter-vehicle distance control is maintained, the approach tendency to the preceding vehicle cannot be suppressed, and the process proceeds to step S127.
In step S129, the inter-vehicle distance control flag is reset to ft = 0 in order to switch (return) from inter-vehicle distance control to inter-vehicle time control.
In step S130, as the inter-vehicle time control, the first acceleration / deceleration command value Gc1 is set to the final acceleration / deceleration command value Gc, and then the routine returns to a predetermined main program.

In step S131, it is determined whether the preceding vehicle has finished decelerating. Here, when the preceding vehicle has finished decelerating, it is determined that the approaching tendency to the preceding vehicle can be suppressed even if the inter-vehicle distance control is returned to the inter-vehicle time control, and the process proceeds to step S132. On the other hand, when the preceding vehicle has not finished decelerating, it is determined that the approach tendency to the preceding vehicle cannot be suppressed unless the inter-vehicle distance control is maintained, and the process proceeds to step S134.
In step S132, the inter-vehicle distance control flag is reset to ft = 0 in order to switch (return) the inter-vehicle distance control to the inter-vehicle time control.
In step S133, as the inter-vehicle time control, the first acceleration / deceleration command value Gc1 is set to the final acceleration / deceleration command value Gc, and then the routine returns to a predetermined main program.
In step S134, as the inter-vehicle distance control, the second acceleration / deceleration command value Gc2 is set to the final acceleration / deceleration command value Gc, and then the routine returns to a predetermined main program.
The above is the control switching determination process of this embodiment.

<Action>
Next, the operation of the first embodiment will be described.
First, a comparative example will be described.
When following a preceding vehicle as a platooning, it is conceivable to control the acceleration / deceleration of the host vehicle according to the inter-vehicle time. However, if the preceding vehicle is merely tracked according to the inter-vehicle time, there is a possibility that the platooning may be disturbed, for example, because the time difference from when the preceding vehicle decelerates until the own vehicle decelerates increases. In particular, the shorter the inter-vehicle time is set, the more uncomfortable the driver is, and further the disturbance of platooning is promoted. In actual platooning, small vehicles and large vehicles are mixed, so the difference in acceleration / deceleration performance that differs for each vehicle also causes disturbance in platooning.

FIG. 4 is a diagram for explaining the disturbance of the vehicle speed in the row running.
(A) in the figure shows three platooning runs, and (b) in the figure is a time chart showing the vehicle speed of each vehicle.
Here, # 1 is the leading vehicle, the # 2 vehicle follows the # 1 vehicle, and the # 3 vehicle follows the # 2 vehicle. Even if the # 1 vehicle decelerates, the # 2 vehicle decelerates with a delay, and the # 3 vehicle decelerates with a delay. Thus, the platooning is disturbed. Further, the deceleration amount of # 2 or # 3 must be increased by delaying the deceleration of vehicle # 2 or # 3 with respect to the deceleration of vehicle # 1. Therefore, when the vehicle speed of the leading vehicle is set to the target vehicle speed, the overshoot amount with respect to the target vehicle speed increases as the vehicle becomes a subsequent vehicle.

FIG. 5 is a diagram for explaining the disturbance of the inter-vehicle time in the platooning.
(A) in the figure shows three platoons, and (b) in the figure is a time chart showing the target inter-vehicle distance and the inter-vehicle distance.
Again, # 1 is the leading vehicle, vehicle # 2 follows vehicle # 1, and vehicle # 3 follows vehicle # 2. And even if the target inter-vehicle distance for realizing the target inter-vehicle time decreases due to the deceleration of the vehicle # 1, the distance between # 1 and # 2 decreases with a delay, and the time between # 2 and # 3 decreases with a delay. Will be disturbed, and the rowing will be disturbed. Moreover, the deceleration amount of # 2 and # 3 must be increased because the decrease of the inter-vehicle distance between # 1 and # 2 and between # 2 and # 3 is delayed with respect to the decrease of the target inter-vehicle distance. Therefore, the amount of overshoot with respect to the target inter-vehicle distance increases as the vehicle becomes a subsequent vehicle.

Next, this embodiment will be described.
In the present embodiment, in a situation where the inter-vehicle time THW can maintain the target inter-vehicle time Tt, inter-vehicle time control is executed, for example, the preceding vehicle decelerates, and the inter-vehicle time THW deviates downward from the target inter-vehicle time Tt. In such a situation, switching from inter-vehicle time control to inter-vehicle distance control is performed.
Here, inter-vehicle time control and inter-vehicle distance control will be described.
The inter-vehicle time control is a mode for controlling the acceleration / deceleration of the host vehicle in order to realize the target inter-vehicle time Tt.

  First, in the vehicle group, the target inter-vehicle time Tt is set according to whether the host vehicle is the leading vehicle or the following vehicle. When the own vehicle is the leading vehicle, the target is longer than when the own vehicle is the following vehicle. The inter-vehicle time Tt is set (step S103). Then, a first target inter-vehicle distance Dt1 for realizing the target inter-vehicle time Tt is calculated (step S104), and a target vehicle speed Vt for realizing the first target inter-vehicle distance Dt1 is calculated (step S105). Then, a target acceleration / deceleration Gt for realizing the target vehicle speed Vt is calculated (step S106), and a rate limiter process is performed on the target acceleration / deceleration Gt (step S107). Then, a first acceleration / deceleration command value Gc1 for realizing the target acceleration / deceleration Gt is calculated (step S108), and the first acceleration / deceleration command value Gc1 is set as a final deceleration command value Gc (step S108). S111). Then, an engine torque command value and a brake fluid pressure command value as control command values are set according to the final deceleration command value Gc (step S112), and the driving force control device 20 and the brake control device are set accordingly. 50 is controlled (step S113). The inter-vehicle time control is executed in such a procedure.

On the other hand, the inter-vehicle distance control is a mode for controlling the acceleration / deceleration of the host vehicle in order to realize the second target inter-vehicle distance Dt2.
First, it is determined whether or not the preceding vehicle starts to decelerate (step S109). Then, the inter-vehicle distance Dr with the preceding vehicle at the time when the deceleration start of the preceding vehicle is detected is set as the second target inter-vehicle distance Dt2, and the second target inter-vehicle distance Dt2 is maintained. An acceleration / deceleration command value Gc2 is set (step S110). The second acceleration / deceleration command value Gc2 is a deceleration command for generating a deceleration according to the deviation ΔD between the second target inter-vehicle distance Dt2 and the inter-vehicle distance Dr. The second acceleration / deceleration command value Gc2 is the final value. Is set as an actual deceleration command value Gc (step S111). Then, an engine torque command value and a brake fluid pressure command value as control command values are set according to the final deceleration command value Gc (step S112), and the driving force control device 20 and the brake control device are set accordingly. 50 is controlled (step S113). The inter-vehicle distance control is executed in such a procedure.

  In the inter-vehicle time control, the acceleration / deceleration of the host vehicle is controlled in order to realize the target inter-vehicle time Tt, so that smooth and stable while allowing (absorbing) some fluctuations in the inter-vehicle distance Dr and the own vehicle speed Vs. Follow-up driving can be performed. Therefore, this inter-vehicle time control is suitable in a situation where the preceding vehicle is traveling at a substantially constant speed and the inter-vehicle time THW can maintain the target inter-vehicle time Tt. On the other hand, in the inter-vehicle distance control, the inter-vehicle distance Dr at the time when the preceding vehicle starts decelerating is set as the second target inter-vehicle distance Dt2, and in order to realize the second target inter-vehicle distance Dt2, The speed is controlled. That is, when the deceleration start of the preceding vehicle is detected, the host vehicle immediately starts decelerating as the inter-vehicle distance Dr decreases, so that the approach to the preceding vehicle can be suppressed with high response. Therefore, for example, in a situation where the preceding vehicle decelerates and the inter-vehicle time THW deviates downward from the target inter-vehicle time Tt, the inter-vehicle distance control is suitable.

In this way, instead of responding only by inter-vehicle time control, by executing inter-vehicle distance control as necessary, the vehicle following the preceding vehicle can be decelerated at a more appropriate timing, and good platooning can be maintained. can do.
However, when the inter-vehicle time THW falls below the target inter-vehicle time Tt, switching from the inter-vehicle time control to the inter-vehicle distance control immediately may cause a sudden change in the vehicle behavior. For this reason, a predetermined lower limit threshold Tth _MIN is set in a range smaller than the target inter-vehicle time Tt, and a range from the target inter-vehicle time Tt to the lower limit threshold Tth _MIN is set as a dead zone for maintaining the inter-vehicle time control.

That is, when the inter-vehicle time THW falls below the target inter-vehicle time Tt, the inter-vehicle time control is not immediately switched from the inter-vehicle time control to the inter-vehicle distance control, but in the inter-vehicle time control, there is a margin in the inter-vehicle time THW for switching to the inter-vehicle distance control. I have it. Accordingly, when the inter-vehicle time THW is equal to or greater than the lower limit threshold Tth _MIN (determination in Step S122 is “No”), the inter-vehicle time control is maintained (Step S124). When the inter-vehicle time THW falls below the lower limit threshold Tth _MIN (“Yes” in step S122), the inter-vehicle distance control flag is set to ft = 1 (step S126), and the inter-vehicle time control is changed to the inter-vehicle distance control. (Step S127).

  As described above, first, while performing the inter-vehicle time control, the vehicle behavior is approached as when the inter-vehicle distance control is performed, and then the shift to the inter-vehicle distance control is performed. That is, it waits until the first acceleration / deceleration command value Gc1 approaches the second acceleration / deceleration command value Gc2, and then switches from the first acceleration / deceleration command value Gc1 to the second acceleration / deceleration command value Gc2, Controls the acceleration / deceleration speed. Thereby, a control mode can be switched smoothly and the sudden change of a vehicle behavior can be suppressed. In this way, when switching from the inter-vehicle time control to the inter-vehicle distance control after detecting the start of deceleration of the preceding vehicle, a deceleration for realizing the second target inter-vehicle distance Dt2 is generated, and the approach to the preceding vehicle with high response is achieved. Can be suppressed.

  On the other hand, when the preceding vehicle releases deceleration while the inter-vehicle distance control is being executed, if the own vehicle's deceleration release is delayed with respect to this deceleration release, the follow-up to the preceding vehicle is delayed, which again disturbs platooning. Will end up. Therefore, it is determined whether or not the preceding vehicle ends deceleration (step S121). When the deceleration of the preceding vehicle is detected (determination in step S128 or S131 is “Yes”), the inter-vehicle distance control flag is reset to ft = 0 (step S129 or S132), and the inter-vehicle time control is started. Return (step S130 or S133). In this way, when the preceding vehicle releases the deceleration, switching from the inter-vehicle distance control to the inter-vehicle time control prevents the inter-vehicle distance Dr with the preceding vehicle from being unnecessarily enlarged, and maintains good platooning. Can do.

  Further, whether or not the preceding vehicle has started decelerating and whether or not the preceding vehicle has finished decelerating are determined by detecting the deceleration state of the preceding vehicle via the communication device 14. This is because if the deceleration state of the preceding vehicle is detected according to the relative speed Vr with the preceding vehicle without using inter-vehicle communication, there is a possibility that a delay may occur in the determination. In addition, there is a certain difference in response from the deceleration operation to the actual change in vehicle behavior. Therefore, if the brake switch ON / OFF signal or the transmission shift operation signal is input by inter-vehicle communication with the preceding vehicle, the deceleration state of the preceding vehicle is determined before the behavior of the preceding vehicle actually changes. be able to. In this way, by determining the deceleration state of the preceding vehicle through inter-vehicle communication with the preceding vehicle via the communication device 14, the acceleration / deceleration of the host vehicle can be controlled at a more appropriate timing, and good platooning can be maintained. can do.

  The second target inter-vehicle distance Dt2 for performing inter-vehicle distance control is set to the inter-vehicle distance Dr when the preceding vehicle starts decelerating. Therefore, the second target inter-vehicle distance Dt2 corresponds to a value at the time when the inter-vehicle distance Dr starts to decrease due to the deceleration of the preceding vehicle. Furthermore, as described above, by inputting the ON / OFF signal of the brake switch of the preceding vehicle and the shift operation signal of the transmission, it corresponds to the value at the time before the inter-vehicle distance Dr is reduced by the deceleration of the preceding vehicle. To do. Therefore, by setting the inter-vehicle distance Dr at the start of deceleration as the target value for inter-vehicle distance control, the acceleration / deceleration of the host vehicle is controlled so as to maintain the state before the preceding vehicle starts decelerating. Thereby, the approach to a preceding vehicle can be suppressed as much as possible, and good row running can be maintained.

FIG. 6 is a time chart showing the operation of the first embodiment.
Here, the movement of the inter-vehicle time THW, the deceleration signal of the preceding vehicle, and the inter-vehicle distance control flag will be described.
First, the inter-vehicle time control is executed because the inter-vehicle time THW substantially maintains the target inter-vehicle time Tt and the inter-vehicle distance control flag is reset to ft = 0. At this time, the preceding vehicle starts decelerating at time t11, and the preceding vehicle ends decelerating at time t12. Although the inter-vehicle time THW slightly decreases due to the temporary deceleration of the preceding vehicle, the inter-vehicle distance control flag is also maintained at ft = 0 because the inter-vehicle distance control flag is maintained at or above the lower limit threshold th _MIN. continue.

When the preceding vehicle starts decelerating thereafter at time t13, the inter-vehicle time THW decreases, and when the inter-vehicle time THW falls below the lower limit threshold th _MIN at time t14, the inter-vehicle distance control flag is set to ft = 1. Switch from inter-vehicle time control to inter-vehicle distance control. This inter-vehicle distance control decelerates to maintain the inter-vehicle distance Dr when the preceding vehicle starts decelerating, so the inter-vehicle time THW starts to increase and immediately exceeds the lower limit threshold th _MIN , but the inter-vehicle distance control is maintained as it is. . When the preceding vehicle finishes decelerating thereafter at time t15, the inter-vehicle distance control flag is reset to ft = 0, and the inter-vehicle distance control returns to the inter-vehicle time control.
In this way, instead of responding only by inter-vehicle time control, by executing inter-vehicle distance control as necessary, the vehicle following the preceding vehicle can be decelerated at a more appropriate timing, and good platooning can be maintained. can do.

《Correspondence relationship》
From the above, the wheel speed sensor 12 and the process of step S102 correspond to the “vehicle speed detection unit”, and the surrounding situation recognition device 13 corresponds to the “inter-vehicle distance detection unit”. Further, the processing of the CACC switch 11 and step S103 corresponds to the “target inter-vehicle time setting unit”, and the processing of steps S104 to S108, S112, and S113 corresponds to the “inter-vehicle time control unit”. Further, the processing of the communication device 14 and steps S109 and S121 corresponds to the “deceleration state detection unit”, and the processing of step S110 corresponds to the “target vehicle distance setting unit” and the “vehicle distance control unit”. Further, the process of step S111, that is, the processes of steps S122 to S134 correspond to the “control switching unit”.

"effect"
Next, the effect of the main part in 1st Embodiment is described.
(1) The convoy travel control device according to this embodiment forms a convoy with a plurality of vehicles on the same lane, sets a target inter-vehicle time Tt for the preceding vehicle, and realizes the target inter-vehicle time Tt. Therefore, the inter-vehicle time control for controlling the acceleration / deceleration of the host vehicle is made executable. Further, the deceleration state of the preceding vehicle is detected, the inter-vehicle distance Dr with the preceding vehicle is detected, and the inter-vehicle distance Dr at the time when the preceding vehicle has started decelerating is set as the second target inter-vehicle distance Dt2. . And in order to implement | achieve 2nd target inter-vehicle distance Dt2, inter-vehicle distance control which controls the acceleration / deceleration of the own vehicle is enabled. Further, the host vehicle speed Vs is detected, and the inter-vehicle time THW for the preceding vehicle is detected according to the host vehicle speed Vs and the inter-vehicle distance Dr with the preceding vehicle. In accordance with the inter-vehicle time THW, the control is switched to either the inter-vehicle time control or the inter-vehicle distance control. At this time, the inter-vehicle time control is performed when the inter-vehicle time THW maintains the target inter-vehicle time Tt. Further, a predetermined lower threshold Tth _MIN is set in a range smaller than the target inter-vehicle time Tt, and a range from the target inter-vehicle time Tt to the lower threshold Tth _MIN is set as a dead zone for maintaining the inter-vehicle time control. Then, when the inter-vehicle time control is being performed and the inter-vehicle time THW falls below the lower limit threshold Tth _MIN , the inter-vehicle time control is switched to the inter-vehicle distance control.
In this way, instead of responding only by inter-vehicle time control, by executing inter-vehicle distance control as necessary, the vehicle following the preceding vehicle can be decelerated at a more appropriate timing, and good platooning can be maintained. can do. Furthermore, by setting the range from the target inter-vehicle time Tt to the lower limit threshold value Tth _MIN as a dead zone for maintaining the inter-vehicle time control, it is possible to smoothly switch the control mode and suppress sudden changes in vehicle behavior. Further, when the inter-vehicle time THW falls below the lower limit threshold value Tth _MIN , by switching from the inter-vehicle time control to the inter-vehicle distance control, the approach to the preceding vehicle is quickly suppressed in order to realize the second target inter-vehicle distance Dt2. can do.

(2) The convoy travel control apparatus according to the present embodiment switches from the inter-vehicle distance control to the inter-vehicle time control when the preceding vehicle finishes decelerating.
In this way, when the preceding vehicle finishes decelerating, switching from inter-vehicle distance control to inter-vehicle time control prevents the inter-vehicle distance Dr from unnecessarily increasing and maintains good platooning can do.

(3) The convoy travel control apparatus according to the present embodiment detects the deceleration state of the preceding vehicle through communication with the preceding vehicle.
In this way, by detecting the deceleration state of the preceding vehicle through communication with the preceding vehicle, the acceleration / deceleration of the host vehicle can be controlled at a more appropriate timing, and good platooning can be maintained.

(4) The convoy travel control method according to the present embodiment sets a target inter-vehicle time Tt for the preceding vehicle and realizes this target inter-vehicle time Tt when traveling in a convoy with a plurality of vehicles on the same lane. Therefore, it is possible to execute inter-vehicle time control for controlling the acceleration / deceleration of the host vehicle. Further, the deceleration state of the preceding vehicle is detected, the inter-vehicle distance Dr with the preceding vehicle is detected, and the inter-vehicle distance Dr at the time when the preceding vehicle has started decelerating is set as the second target inter-vehicle distance Dt2. . And in order to implement | achieve 2nd target inter-vehicle distance Dt2, inter-vehicle distance control which controls the acceleration / deceleration of the own vehicle is enabled. Further, the host vehicle speed Vs is detected, and the inter-vehicle time THW for the preceding vehicle is detected according to the host vehicle speed Vs and the inter-vehicle distance Dr. When the inter-vehicle time THW maintains the target inter-vehicle time Tt, inter-vehicle time control is performed. Further, a predetermined lower threshold Tth _MIN is set in a range smaller than the target inter-vehicle time Tt, and a range from the target inter-vehicle time Tt to the lower threshold Tth _MIN is set as a dead zone for maintaining the inter-vehicle time control. Then, when the inter-vehicle time control is being performed and the inter-vehicle time THW falls below the lower limit threshold Tth _MIN , the inter-vehicle time control is switched to the inter-vehicle distance control.

In this way, instead of responding only by inter-vehicle time control, by executing inter-vehicle distance control as necessary, the vehicle following the preceding vehicle can be decelerated at a more appropriate timing, and good platooning can be maintained. can do. Furthermore, by setting the range from the target inter-vehicle time Tt to the lower limit threshold value Tth _MIN as a dead zone for maintaining the inter-vehicle time control, it is possible to smoothly switch the control mode and suppress sudden changes in vehicle behavior. Further, when the inter-vehicle time THW falls below the lower limit threshold value Tth _MIN , by switching from the inter-vehicle time control to the inter-vehicle distance control, the approach to the preceding vehicle is quickly suppressed in order to realize the second target inter-vehicle distance Dt2. can do.

<< Second Embodiment >>
"Constitution"
The present embodiment maintains the inter-vehicle distance control when the inter-vehicle time THW exceeds the target inter-vehicle time Tt in the state where the inter-vehicle distance control is performed. Further, an upper limit threshold value _{Tth MAX} for the time headway THW, when the time headway THW is above the upper threshold value _{Tth MAX,} in order to realize the maintenance of the vehicle distance _{Dth MAX} corresponding to the upper limit threshold value _{Tth MAX,} acceleration of the vehicle It controls the speed.
The apparatus configuration is the same as that of the first embodiment described above.

Next, the control switching determination process of this embodiment will be described.
FIG. 7 is a flowchart illustrating a control switching determination process according to the second embodiment.
Here, in the first embodiment described above, new processes of steps S201 and S202 are added, and the process of step S201 is executed when the process proceeds from step S123 to S131. In addition, about the process of step S121-S134, since it is the same as that of 1st Embodiment mentioned above, detailed description is abbreviate | omitted about a common part.

In step S201, it is determined whether the inter-vehicle time THW is shorter than a predetermined upper limit threshold Tth _MAX .
Here, the upper limit threshold value Tth _MAX is a value obtained by adding a predetermined margin Tm from the target inter-vehicle time Tt set by the inter-vehicle time setting switch, as shown in the following equation. The margin Tm is, for example, about 0.1 [sec]. Therefore, when the target inter-vehicle time Tt is, for example, 0.7 [sec], the upper limit threshold Tth _MAX is about 0.8 [sec].
Tth _MAX = Tt + Tm
Here, when the determination result indicates that the inter-vehicle time THW is shorter than the upper limit threshold Tth _MAX , it is determined that there is almost no tendency to separate from the preceding vehicle, and the process proceeds to step S131. On the other hand, if the determination result is that the inter-vehicle time THW is equal to or greater than the upper limit threshold Tth _MAX, it is determined that the vehicle is in a separation tendency from the preceding vehicle, and the process proceeds to step S202.

In step S202, the inter-vehicle distance control, the upper threshold _{Tth MAX} considerable inter-vehicle distance _{Dth MAX,} and set as a second target inter-vehicle distance Dt2, and a second acceleration for maintaining the second target inter-vehicle distance Dt2 A speed command value Gc2 is set. Here, the upper limit threshold value _{Tth MAX} considerable inter-vehicle distance _{Dth MAX,} as shown in the equation below is a value obtained by multiplying the vehicular velocity Vs to the upper threshold _{Tth MAX.}
Dth _MAX = Tth _MAX x Vs
Then, the second acceleration / deceleration command value Gc2 is set to the final acceleration / deceleration command value Gc, and then the process returns to the predetermined main program.
The above is the control switching determination process of this embodiment.

<Action>
Next, the operation of the second embodiment will be described.
When the inter-vehicle distance control is executed and the preceding vehicle has not finished decelerating, for example, if the deceleration of the host vehicle is relatively higher than the deceleration of the preceding vehicle, the inter-vehicle time THW gradually increases. Go. Even if the inter-vehicle time THW exceeds the target inter-vehicle time Tt, the preceding vehicle has not released the deceleration, so the inter-vehicle distance control is maintained as it is.
However, if the inter-vehicle time THW deviates upward from the target inter-vehicle time Tt and the difference from the target inter-vehicle time Tt becomes too large, the inter-vehicle time THW is returned to the target inter-vehicle time Tt after the preceding vehicle releases the deceleration. It takes time to complete.

Therefore, when a predetermined upper limit threshold Tth _MAX is set in a range larger than the target inter-vehicle time Tt and the inter-vehicle time THW is equal to or greater than the upper threshold Tth _MAX (“No” in step S201), the second inter-vehicle distance control is performed. The second target inter-vehicle distance Dt2 is adjusted. That is, the upper threshold Tth _MAX considerable inter-vehicle distance Dth _MAX, resets the second target inter-vehicle distance Dt2, in order to realize the maintenance of the second target inter-vehicle distance Dt2, to control the acceleration and deceleration of the vehicle (Step S202). In this way, the inter-vehicle time THW is prevented from becoming too large while executing the inter-vehicle distance control. Thereby, after the preceding vehicle releases the deceleration, the inter-vehicle time THW can be quickly converged to the target inter-vehicle time Tt.

FIG. 8 is a time chart showing the operation of the second embodiment.
Here, the movement of the inter-vehicle time THW, the deceleration signal of the preceding vehicle, and the inter-vehicle distance control flag will be described.
First, the inter-vehicle time control is executed because the inter-vehicle time THW substantially maintains the target inter-vehicle time Tt and the inter-vehicle distance control flag is reset to ft = 0. At this time, the preceding vehicle starts decelerating at time t21, and the preceding vehicle ends decelerating at time t22. Although the inter-vehicle time THW slightly decreases due to the temporary deceleration of the preceding vehicle, the inter-vehicle distance control flag is also maintained at ft = 0 because the inter-vehicle distance control flag is maintained at or above the lower limit threshold th _MIN. continue.

When the preceding vehicle starts decelerating at time t23 thereafter, the inter-vehicle time THW decreases, and when the inter-vehicle time THW falls below the lower limit threshold th _MIN at the time t24, the inter-vehicle distance control flag is set to ft = 1. Switch from inter-vehicle time control to inter-vehicle distance control. This inter-vehicle distance control decelerates to maintain the inter-vehicle distance Dr when the preceding vehicle starts decelerating, so the inter-vehicle time THW starts to increase and immediately exceeds the lower limit threshold th _MIN , but the inter-vehicle distance control is maintained as it is. . In addition, the inter-vehicle time THW continues to increase and exceeds the target inter-vehicle time Tt. However, since the preceding vehicle has not released the deceleration, the inter-vehicle distance control is maintained as it is.

However, the time headway THW is beyond the upper limit threshold value _{th MAX,} while maintaining the inter-vehicle distance control, the upper limit threshold value _{th MAX} considerable inter-vehicle distance _{Dth MAX,} is set as the second target inter-vehicle distance Dt2. As a result, the increase in the inter-vehicle time THW is suppressed, and the upper limit threshold th _MAX is substantially maintained. When the preceding vehicle finishes decelerating thereafter at time t25, the inter-vehicle distance control flag is reset to ft = 0, and the inter-vehicle distance control returns to the inter-vehicle time control.
In this way, by adjusting the second target inter-vehicle distance Dt2 while maintaining the inter-vehicle distance control, it is possible to suppress the inter-vehicle time THW from becoming too large and maintain a good platooning.
In the present embodiment, other parts common to the first embodiment described above are assumed to have the same operational effects, and detailed description thereof is omitted.

《Correspondence relationship》
As described above, the process of step S201 is included in the “control switching unit”, and the process of step S202 is included in the “inter-vehicle distance control unit”.
"effect"
Next, the effect of the main part in 2nd Embodiment is described.
(1) The convoy travel control device of the present embodiment maintains the inter-vehicle distance control when the inter-vehicle time THW exceeds the target inter-vehicle time Tt in a state where the inter-vehicle distance control is being performed.
Thus, even if the inter-vehicle time THW exceeds the target inter-vehicle time Tt, the approach to the preceding vehicle can be suppressed by maintaining the inter-vehicle distance control at least until the preceding vehicle finishes decelerating.

(2) The row running control device of the present embodiment sets a predetermined upper limit threshold Tth _MAX in a range larger than the target inter-vehicle time Tt, and when the inter-vehicle time THW exceeds the upper limit threshold Tth _MAX , the upper limit threshold Tth _In order to maintain the inter-vehicle distance Dth _MAX corresponding to _MAX , the acceleration / deceleration of the host vehicle is controlled.
Thus, when the time headway THW is above the upper threshold value _{Tth MAX} by maintaining the upper threshold _{Tth MAX} considerable inter-vehicle distance _{Dth MAX,} and prevent the time headway THW becomes too large, good row running Can be maintained.

<< Third Embodiment >>
"Constitution"
In the present embodiment, when the vehicle speed Va of the preceding vehicle becomes equal to or less than a predetermined threshold value Vth, the acceleration / deceleration of the host vehicle is realized in order to maintain a predetermined minimum inter-vehicle distance Dr _MIN as inter-vehicle distance control. Is to control.
The apparatus configuration is the same as that of the first embodiment described above.

Next, the control switching determination process of this embodiment will be described.
FIG. 9 is a flowchart illustrating a control switching determination process according to the third embodiment.
Here, in the first embodiment described above, new processes of steps S301 and S302 are added, and the process of step S301 is executed before step S121. In addition, about the process of step S121-S134, since it is the same as that of 1st Embodiment mentioned above, detailed description is abbreviate | omitted about a common part.

In step S301, it is determined whether the vehicle speed Va of the preceding vehicle is greater than a predetermined threshold value Vth. Here, the threshold value Vth is a value of about 40 to 50 km / h, for example. When the determination result is Va> Vth, it is determined that appropriate inter-vehicle time control can be executed, and the process proceeds to step S121. On the other hand, when the determination result is Va ≦ Vth, it is determined that appropriate inter-vehicle time control cannot be executed, and the process proceeds to step S302.
In step S302, as the inter-vehicle distance control, a predetermined minimum inter-vehicle distance Dr _MIN is set as the second target inter-vehicle distance Dt2, and a second acceleration / deceleration command for maintaining the second target inter-vehicle distance Dt2 is set. The value Gc2 is set. Here, the minimum inter-vehicle distance Dr _MIN is a fixed value of about 10 m, for example. Then, the second acceleration / deceleration command value Gc2 is set to the final acceleration / deceleration command value Gc, and then the process returns to the predetermined main program.
The above is the control switching determination process of this embodiment.

<Action>
Next, the operation of the third embodiment will be described.
In the inter-vehicle time control, when the target inter-vehicle time Tt is to be realized, the inter-vehicle distance to the preceding vehicle changes depending on the host vehicle speed Vs. That is, the higher the own vehicle speed Vs, the longer the inter-vehicle distance Dr. However, the lower the own vehicle speed Vs, the shorter the inter-vehicle distance Dr. For example, the inter-vehicle distance Dr is about 8.3 m when the own vehicle speed Vs is about 50 km / h, and the inter-vehicle distance Dr is about 6.6 m when the own vehicle speed Vs is about 40 km / h. However, no matter how low the vehicle speed Vs is, if the inter-vehicle distance Dr is too short, the driver may feel uncomfortable. Therefore, in this embodiment, even if the host vehicle speed Vs decreases, in order to maintain the minimum inter-vehicle distance Dr, switching from inter-vehicle time control to inter-vehicle distance control is performed.

In the case of platooning, the own vehicle speed Vs is substantially the vehicle speed Va of the preceding vehicle. First, the vehicle speed Va of the preceding vehicle changes, and then the own vehicle speed Vs changes, so it is detected that the own vehicle speed Vs is low. It is preferable to detect that the vehicle speed Va of the preceding vehicle is low rather than to do so.
Therefore, when the vehicle speed Va of the preceding vehicle is equal to or lower than the threshold value Vth (the determination in step S301 is “No”), the second target inter-vehicle distance Dt2 in the inter-vehicle distance control is adjusted. That is, the predetermined minimum inter-vehicle distance Dr _MIN is reset as the second target inter-vehicle distance Dt2, and the acceleration / deceleration of the host vehicle is controlled in order to realize the maintenance of the second target inter-vehicle distance Dt2 (step) S302). In this way, the inter-vehicle distance control is switched to suppress the inter-vehicle distance Dr from becoming too small. Thereby, it can suppress approaching more than necessary with respect to a preceding vehicle, and it can also suppress giving a driver uncomfortable feeling.

FIG. 10 is a time chart showing the operation of the third embodiment.
Here, the movement of the vehicle speed Va of the preceding vehicle and the inter-vehicle distance Dr will be described.
First, the state in which the vehicle speed Va of the preceding vehicle is larger than the threshold value Vth is maintained. At this time, inter-vehicle time control is executed. When the preceding vehicle decelerates from this state and the vehicle speed Va gradually decreases, the inter-vehicle distance Dr also gradually decreases due to the inter-vehicle time control. Thereafter, when the vehicle speed Va of the preceding vehicle falls below the threshold value Vth at time t31, the vehicle time control is switched to the vehicle distance control. By this inter-vehicle distance control, the reduction of the inter-vehicle distance Dr is limited, and the minimum inter-vehicle distance Dr _MIN is maintained.

In this way, by switching from the inter-vehicle time control to the inter-vehicle distance control and adjusting the second target inter-vehicle distance Dt2, it is possible to prevent the vehicle from approaching the preceding vehicle too much and maintain good platooning.
In the present embodiment, other parts common to the first embodiment described above are assumed to have the same operational effects, and detailed description thereof is omitted.
《Correspondence relationship》
As described above, the process of step S301 is included in the “control switching unit”, and the process of step S302 is included in the “inter-vehicle distance control unit”.

"effect"
Next, the effect of the main part in 3rd Embodiment is described.
(1) The convoy travel control apparatus of the present embodiment realizes maintenance of a predetermined minimum inter-vehicle distance Dr _MIN as inter-vehicle distance control when the vehicle speed Va of the preceding vehicle becomes equal to or less than a predetermined threshold Vth. Therefore, the acceleration / deceleration of the host vehicle is controlled.
As described above, when the vehicle speed Va of the preceding vehicle becomes equal to or lower than the threshold value Vth, by maintaining the minimum inter-vehicle distance Dr _MIN by the inter-vehicle distance control, it is possible to suppress the approaching vehicle from being too close and to perform good platooning. Can be maintained.

  Although the present invention has been described with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of the embodiments based on the above disclosure are obvious to those skilled in the art. Moreover, each embodiment can be adopted in any combination.

11 CACC switch 12 Wheel speed sensor 13 Peripheral situation recognition device 14 Communication device 15 Navigation system 16 Controller 20 Driving force control device 50 Brake control device

Claims (7)

In a row running control device that runs in a row with a plurality of vehicles on the same lane,
A target inter-vehicle time setting unit for setting a target inter-vehicle time for the preceding vehicle;
In order to realize the target inter-vehicle time set by the target inter-vehicle time setting unit, an inter-vehicle time control unit that performs inter-vehicle time control by controlling the acceleration / deceleration of the host vehicle,
A deceleration state detector for detecting a deceleration state of the preceding vehicle;
An inter-vehicle distance detection unit for detecting an inter-vehicle distance from the preceding vehicle;
A target inter-vehicle distance setting unit that sets the inter-vehicle distance detected by the inter-vehicle distance detection unit as a target inter-vehicle distance when the deceleration state detection unit detects that the preceding vehicle has started to decelerate;
In order to realize the target inter-vehicle distance set by the target inter-vehicle distance setting unit, an inter-vehicle distance control unit that performs inter-vehicle distance control by controlling the acceleration / deceleration of the host vehicle,
A vehicle speed detector for detecting the vehicle speed;
An inter-vehicle time detection unit that detects an inter-vehicle time with respect to the preceding vehicle according to an own vehicle speed detected by the vehicle speed detection unit and an inter-vehicle distance with the preceding vehicle detected by the inter-vehicle distance detection unit;
A control switching unit that switches between either the inter-vehicle time control by the inter-vehicle time control unit or the inter-vehicle distance control by the inter-vehicle distance control unit according to the inter-vehicle time detected by the inter-vehicle time detection unit. ,
The control switching unit
When the inter-vehicle time maintains the target inter-vehicle time, the inter-vehicle time control unit performs inter-vehicle time control, sets a predetermined lower limit threshold in a range smaller than the target inter-vehicle time, and the target inter-vehicle time Is set as a dead zone for maintaining the inter-vehicle time control, and the inter-vehicle time control is performed when the inter-vehicle time falls below the lower-limit threshold in the state where the inter-vehicle time control is performed. A convoy travel control device characterized in that the control is switched to the inter-vehicle distance control. The control switching unit
The platooning travel control device according to claim 1, wherein the deceleration state detection unit switches from the inter-vehicle distance control to the inter-vehicle time control when the preceding vehicle finishes decelerating. The deceleration state detector is
The row running control device according to claim 1, wherein a deceleration state of the preceding vehicle is detected by communication with the preceding vehicle. The control switching unit
The platoon according to any one of claims 1 to 3, wherein the inter-vehicle distance control is maintained when the inter-vehicle time exceeds the target inter-vehicle time while the inter-vehicle distance control is being performed. Travel control device. The inter-vehicle distance control unit
A predetermined upper limit threshold is set in a range larger than the target inter-vehicle time, and when the inter-vehicle time exceeds the upper threshold, the vehicle is adjusted in order to maintain the inter-vehicle distance corresponding to the upper threshold The row running control device according to claim 4, wherein the row running control device controls the speed. The control switching unit
When the vehicle speed of the preceding vehicle is equal to or less than a predetermined threshold, the inter-vehicle distance control unit performs inter-vehicle distance control,
The inter-vehicle distance control unit
The platooning control device according to any one of claims 1 to 5, wherein an acceleration / deceleration of the host vehicle is controlled in order to maintain a predetermined minimum inter-vehicle distance. When traveling in a formation with multiple vehicles on the same lane,
In order to set the target inter-vehicle time for the preceding vehicle and realize the target inter-vehicle time, it is possible to execute inter-vehicle time control for controlling the acceleration / deceleration of the host vehicle,
Detecting a deceleration state of the preceding vehicle, detecting an inter-vehicle distance from the preceding vehicle, setting the inter-vehicle distance at the time when the preceding vehicle has started decelerating as a target inter-vehicle distance, In order to realize the distance, it is possible to execute inter-vehicle distance control that controls acceleration / deceleration of the host vehicle,
The own vehicle speed is detected, the following time is detected for the preceding vehicle according to the own vehicle speed and the inter-vehicle distance, and the inter-vehicle time control is performed when the inter-vehicle time maintains the target inter-vehicle time. A predetermined lower threshold is set in a range smaller than the target inter-vehicle time, a range from the target inter-vehicle time to the lower threshold is set as a dead zone for maintaining the inter-vehicle time control, and the inter-vehicle time control When the inter-vehicle time falls below the lower limit threshold while the vehicle is being operated, the convoy travel control method switches from the inter-vehicle time control to the inter-vehicle distance control.

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