JP5509554B2 - Vehicle travel support device and vehicle travel support method - Google Patents

Description

  The present invention relates to a vehicle travel support technology that avoids contact between an own vehicle and an obstacle.

Conventionally, as this type of technology, for example, there is a technology described in Patent Document 1.
In this prior art, an obstacle that is an obstacle to traveling of the host vehicle is detected. Then, the own vehicle performs steering control so as to turn and avoid the detected obstacle, thereby avoiding contact between the own vehicle and the obstacle.
JP-A-2005-173663

In the technique described in Patent Document 1, the steering control is continued until the traveling control device determines that contact between the host vehicle and the obstacle is avoided.
However, in a situation where the driving control device performs steering control to avoid the obstacle and the possibility of contact between the host vehicle and the obstacle is reduced, the driving action of the driver is a driving operation that avoids the obstacle. There is a possibility of shifting to a driving operation according to the next purpose.

In such a case, the contents of the driver's steering operation and the steering control by the travel control device do not match, and a situation may occur in which the driver feels uncomfortable.
In particular, when the traveling speed of the vehicle decreases, the steering torque required for steering the steered wheels increases. Therefore, in a situation where the traveling speed of the host vehicle is reduced, there is a possibility that the steering torque that the steering control applies to the steering system increases. As a result, the discomfort caused by the discrepancy between the driver's steering operation and the steering control by the travel control device becomes greater.
The present invention has been made paying attention to the above points, and it is an object of the present invention to reduce a situation in which a driver feels uncomfortable when performing steering control to avoid contact with an obstacle.

In order to solve the above problem, an aspect of the present invention is to avoid contact with an obstacle when the steering avoidance ability of the host vehicle is lower than the braking avoidance ability with respect to the detected obstacle. It was decided to suppress the steering control that had been performed in the past.

According to the present invention, when the steering avoidance ability is lower than the braking avoidance ability and the contact avoidance effect with the obstacle by the steering control is reduced, the steering control is suppressed.
As a result, even when steering control for avoiding contact with an obstacle is performed, it is possible to reduce a situation where a driver feels uncomfortable when performing a steering operation.

Embodiments of the present invention will be described below with reference to the drawings.
In the present embodiment, an example in which the driving support apparatus according to the present invention is applied to a vehicle is shown.
This vehicle detects an obstacle SM that is an obstacle to traveling of the host vehicle SW, and performs braking force control and steering control so as to avoid contact between the host vehicle SW and the obstacle SM.
(Constitution)
First, the structure of the vehicle of this embodiment is demonstrated.

FIG. 1 is a schematic configuration diagram illustrating a vehicle according to the present embodiment.
The vehicle 1 includes a braking force control unit 2, a steering control unit 3, an external environment detection unit 4, a vehicle state detection unit 5, and a main control unit 6.
The braking force control unit 2 includes a brake pedal 8, a booster 9, a master cylinder 10, and wheel cylinders 11FL to 11RR. And according to the depression amount of the brake pedal 8 by a driver | operator, the braking fluid pressure | voltage-risen with the master cylinder 10 is supplied to each wheel cylinder 11FL-11RR. Thereby, each wheel 7FL-7RR generate | occur | produces braking force.

The braking force control unit 2 includes a braking fluid pressure control unit 12.
The brake fluid pressure controller 12 supplies the brake fluid boosted by the master cylinder 10 to the wheel cylinders 11FL to 11RR in accordance with a brake command (described later) output from the main control unit 6. Thereby, the braking force of each wheel 7FL-7RR is controlled.
The steering control unit 3 includes a steering wheel 13 and a steering column 14. And the steering column 14 rotates according to the operation amount of the steering wheel 13 by the driver. Thereby, a turning angle is generated in each of the wheels 7FL to 7RR.

In addition, the steering control unit 3 includes a steering control unit 15.
The steering control unit 15 applies a steering torque to the steering column 14 in accordance with a steering command (described later) output from the main control unit 6. Thereby, the turning angle of each wheel 7FL-7RR is controlled.
Hereinafter, the steering command is also referred to as “power steering controller output value Outval”.
The external environment detection unit 4 includes a laser radar 16, a CCD camera 17, and an external environment detection unit 18.
The laser radar 16 irradiates laser light in front of the vehicle 1 and receives reflected light that is reflected by an object in front of the vehicle 1 and returned.
The CCD camera 17 takes an image of the condition of the traveling road ahead of the vehicle 1.

The external environment detection unit 18 detects the presence or absence of an obstacle SM (for example, another vehicle, a pedestrian, etc.) that becomes an obstacle to the traveling of the host vehicle SW. The obstacle SM is detected based on the result of receiving the reflected light by the laser radar 16 and the imaging result of the condition of the traveling path in the CCD camera 17.
Further, when there is an obstacle SM, the external environment detection unit 18 has obstacle coordinates (St, Sy), a distance between the host vehicle SW and the obstacle SM, a lateral speed Sv of the obstacle SM, The travel path environment and travel path area are also detected. The information on the presence / absence of the obstacle SM, the obstacle coordinates (St, Sy), the distance between the host vehicle SW and the obstacle SM, the lateral speed Sv of the obstacle SM, the road environment, and the road area. Output to the main control unit 6.

Here, the obstacle coordinates (St, Sy) are the positions of the obstacle SM expressed in the vehicle coordinate system (x, y) with reference to the host vehicle SW. The vehicle coordinate system is a coordinate system having an x axis and ay axis that are orthogonal to each other. The center of gravity when the host vehicle SW is viewed in plan is the origin (0.0), the forward direction of the host vehicle SW is the positive direction of the x-axis, and the right direction of the host vehicle SW is the positive direction of the y-axis.
The lateral speed Sv of the obstacle SM is a y-axis direction component of the moving speed of the obstacle SM.

The vehicle state detection unit 5 includes a throttle opening sensor 19, a brake depression amount sensor 20, a braking fluid pressure sensor 21, a steering angle sensor 22, a steering torque sensor 23, wheel speed sensors 24FL to 24RR, a yaw rate sensor 25, and an acceleration sensor 26. Prepare. These sensors output detection result information to the main control unit 6.
The throttle opening sensor 19 detects the throttle opening.

The brake depression amount sensor 20 detects the depression amount of the brake pedal 8.
The brake fluid pressure sensor 21 detects the brake fluid pressure boosted by the master cylinder 10.
The steering angle sensor 22 detects the steering angle of the steering wheel 13.
The steering torque sensor 23 detects the steering torque of the steering wheel 13.
Wheel speed sensors 24FL-24RR detect the rotational speed of each wheel 7FL-7RR.

The yaw rate sensor 25 detects the yaw rate Yr of the vehicle 1.
The acceleration sensor 26 detects accelerations in the front-rear direction and the left-right direction of the vehicle 1.
The main control unit 6 is composed of a microprocessor.
The microprocessor includes an integrated circuit including an A / D conversion circuit, a D / A conversion circuit, a central processing unit, and a memory. And based on the various information which the external environment detection unit 4 and the vehicle state detection unit 5 output, according to the program in memory, a braking command is output to the braking force control unit 2, and a steering command is output to the steering control unit 3.

(Main control unit configuration)
Next, the configuration of the main control unit 6 will be further described.
FIG. 2 is a block flow diagram showing a functional configuration of the main control unit 6.
As shown in FIG. 2, the main control unit 6 includes an external environment detection unit 30, an obstacle position detection unit 31, a host vehicle state detection unit 32, an avoidance target point calculation unit 33, and a target point arrival time calculation unit 34. In addition, an avoidance route calculation means 35, an actuator control means 36, a braking avoidance ability calculation means 37, a steering avoidance ability calculation means 38, an avoidance ability comparison means 39, a control stop determination means 40, and a control command value output means 41 are provided.

The external environment detection means 30 acquires information on the presence / absence of the obstacle SM and information on the traveling road area output from the external environment detection unit 18.
The obstacle position detection means 31 acquires information on the obstacle coordinates (St, Sy) output from the external environment detection unit 18 and information on the lateral speed Sv of the obstacle SM.
The own vehicle state detection means 32 acquires information on the rotational speeds of the wheels 7FL to 7RR output from the wheel speed sensors 24FL to 24RR and information on the yaw rate Yr output from the yaw rate sensor 25. In addition, the host vehicle state detection means 32 calculates the host vehicle speed Vc based on the acquired information on the rotational speeds of the wheels 7FL to 7RR.

  The own vehicle state detection means 32 also includes information on the throttle opening output from the throttle opening sensor 19, information on the depression amount output by the brake depression amount sensor 20, and the braking fluid pressure output by the braking fluid pressure sensor 21. Get information. The own vehicle state detection means 32 calculates the braking / driving force of each of the wheels 7FL to 7RR based on the acquired information on the throttle opening, the information on the depression amount, and the information on the brake fluid pressure.

The avoidance target point calculation means 33 calculates the avoidance target point. The avoidance target point is an end point of a target travel route on which the vehicle 1 travels by steering control.
Specifically, the avoidance target point calculation means 33 is information on the road area detected by the external environment detection means 30 , information on the obstacle coordinates (St, Sy) detected by the obstacle position detection means 31 , and the obstacle SM. The information on the lateral speed Sv is acquired. Further, the avoidance target point calculation means 33 acquires information on the own vehicle speed Vc, braking / driving force, and yaw rate Yr calculated by the own vehicle state detection means 32. And the avoidance target point calculating means 33 calculates an avoidance target point based on the acquired information on the traveling road area, information on the obstacle coordinates (St, Sy), and the like.

The target point arrival time calculating means 34 calculates the target point arrival time TTCm. The target point arrival time TTCm is the time taken for the vehicle 1 to reach the avoidance target point.
Specifically, the target point arrival time calculation unit 34 is based on the information on the own vehicle speed Vc, braking / driving force, and yaw rate Yr detected by the host vehicle state detection unit 32, and the avoidance target point calculated by the avoidance target point calculation unit 33. The target point arrival time TTCm is calculated.

FIG. 3 shows the configuration of an avoidance route calculation means 35, an actuator control means 36, a braking avoidance ability calculation means 37, a steering avoidance ability calculation means 38, an avoidance ability comparison means 39, a control stop determination means 40, and a control command value output means 41. FIG.
The avoidance route calculation means 35 calculates a target steering angle pattern and a target braking force pattern. The target steering angle pattern is time series data of a target steering angle for obstacle avoidance used for steering control. The target braking force pattern is time-series data of target braking force for avoiding obstacles, which is used for braking force control.

Here, with respect to the steering angle, the clockwise direction of the steering wheel 13 is a positive direction and the counterclockwise direction of the steering wheel 13 is a negative direction.
Specifically, the avoidance route calculation means 35 first acquires information on the own vehicle speed Vc, braking / driving force, and yaw rate Yr obtained by the own vehicle state detection means 32. Next, based on the acquired information and the avoidance target point calculated by the avoidance target point calculating means 33, the target travel route of the host vehicle SW is calculated. As the target travel route, a route for allowing the host vehicle SW to pass the side of the obstacle SM and reach the target arrival point is calculated. Next, the avoidance route calculation means 35 calculates a target steering angle pattern so that the host vehicle travels along the target route.

Further, the avoidance route calculation means 35 calculates a target braking force pattern so that the vehicle 1 stops at the avoidance target point based on the host vehicle speed Vc, the braking / driving force, and the avoidance target point.
The actuator control means 36 sequentially generates a steering control output value Contsig. The steering control output value Contsig is a command for causing the steering angle of the steering wheel 13 to follow the target steering angle pattern calculated by the avoidance path calculation means 35. The steering control output value Contsig represents the magnitude of the steering torque applied to the steering column 14.

Further, the actuator control means 36 sequentially outputs a braking command to the braking fluid pressure control unit 12. The braking command is a command for causing the braking force of each of the wheels 7FL to 7RR to follow the target braking force pattern calculated by the avoidance path calculation means 35. The braking command represents the pressure of the braking fluid supplied to the wheel cylinders 11FL to 11RR.
The braking avoidance capability calculating means 37 calculates a braking avoidance capability value TTCb. The braking avoidance ability value TTCb is a parameter representing the ability to avoid contact between the host vehicle SW and the obstacle SM by the braking force control. This ability is hereinafter also referred to as “contact avoidance ability”.

Here, the minimum time necessary for avoiding the obstacle SM by the braking force control is used as the braking avoidance capability value TTCb. The braking avoidance capability value TTCb varies depending on the host vehicle speed Vc. The braking avoidance ability value TTCb is smaller as the contact avoidance ability is higher.
Braking evasion value TTCb, for example, calculated according to "distance the vehicle S W until the avoidance is completed when avoiding an obstacle SM by the braking force control is running / vehicle speed Vc."

The calculation of the braking avoidance capability value TTCb is repeatedly executed at a predetermined cycle.
Specifically, the braking avoidance capability calculation means 37 calculates a braking avoidance capability value TTCb according to the braking control map based on the own vehicle speed Vc calculated by the own vehicle state detection means 32.
FIG. 4 is an explanatory diagram for explaining a braking control map.
As shown in FIG. 4, the braking control map used to calculate the braking avoidance capability value TTCb is a map having the host vehicle speed Vc as the horizontal axis and the braking avoidance capability value TTCb as the vertical axis. In this braking control map, the braking avoidance capability value TTCb increases as the host vehicle speed Vc increases.

Each value of the braking control map is calculated using a vehicle model.
The steering avoidance capability calculation means 38 calculates a steering avoidance capability value TTCs. The steering avoidance ability value TTCs is a parameter representing the contact avoidance ability by the steering control.
Here, as the steering avoidance capability value TTCs, the minimum time necessary for avoiding the obstacle SM by the steering control is used. The steering avoidance capability value TTCs varies depending on the host vehicle speed Vc. The steering avoidance capability value TTCs becomes smaller as the contact avoidance capability increases.

Steering evasion value TTCs, for example, calculated according to "distance / vehicle speed Vc of the vehicle S W until the avoidance is completed when avoiding an obstacle SM by the steering control is running".
The calculation of the steering avoidance capability value TTCs is repeatedly executed at a predetermined cycle.
Specifically, the steering avoidance capability calculation means 38 calculates a steering avoidance capability value TTCs according to the steering control map based on the own vehicle speed Vc calculated by the own vehicle state detection means 32.

FIG. 5 is an explanatory diagram for explaining the steering control map.
FIG. 6 is a diagram in which the control maps of FIGS. 4 and 5 are drawn in an overlapping manner.
As shown in FIG. 5, the steering control map used for calculating the steering avoidance capability value TTCs is a map having the vehicle speed Vc as the horizontal axis and the steering avoidance capability value TTCs as the vertical axis. In this steering control map, the steering avoidance capability value TTCs decreases as the host vehicle speed Vc increases.

  That is, as the host vehicle speed Vc increases, the braking avoidance capability value TTCb increases and the steering avoidance capability value TTCs decreases. Therefore, as shown in FIG. 6, when the host vehicle speed Vc is 0 [km / h] or more and a predetermined threshold speed V1 or less, the steering avoidance capability value TTCs is larger than the braking avoidance capability value TTCb. . When the host vehicle speed Vc is greater than the threshold speed V1, the braking avoidance capability value TTCb is larger than the steering avoidance capability value TTCs.

Each value of the steering control map is calculated using a vehicle model.
The avoidance capability comparison unit 39 generates a control stop output Stp. The control stop output Stp is a parameter indicating whether or not steering control is prohibited.
The generation of the control stop output Stp is repeatedly executed at a predetermined cycle.
Specifically, the avoidance capability comparison unit 39 compares the braking avoidance capability value TTCb calculated by the braking avoidance capability calculation unit 37 with the steering avoidance capability value TTCs calculated by the steering avoidance capability calculation unit 38. Based on the comparison result, a control stop output Stp is generated.

As an example of a method of calculating the control stop output Stp, for example, a method of calculating according to the following equation (1) based on the steering avoidance capability value TTCs and the braking avoidance capability value TTCb can be employed.
Stp = TTCs × Sk−TTCb × Bk (1)
Here, Sk and Bk are coefficients for weighting the steering control and the braking force control.
That is, the threshold is set by weighting the braking avoidance capability value TTCb by the coefficient Bk. Then, a value obtained by subtracting the threshold value TTCb × Bk from the value TTCs × Sk obtained by weighting the steering avoidance capability value TTCs by the coefficient Sk is calculated, and the calculated result is used as the control stop output Stp.

The control stop determination unit 40 generates a steering control stop output value Stoff. The steering control stop output value Stoff is a signal indicating whether or not steering control is prohibited.
The steering control stop output value Stoff is “1” when the steering control is prohibited, and is “0” when the steering control is not prohibited.
The generation of the steering control stop output value Stoff is repeatedly executed at a predetermined cycle.

Specifically, the control stop determination unit 40 generates a steering control stop output value Stoff based on the control stop output Stp output from the avoidance capability comparison unit 39.
As an example of an output method of the steering control stop output value Stoff, for example, the control stop determination unit 40 first determines whether or not the control stop output Stp is “0” or more. Then, "1" and the steering control stop output value Stoff if control stop output Stp is equal to or more than "0". The control stop determination unit 40, when the control stop output S tp is determined as "0" is smaller than the steering control stop output value Stoff "0".

That is, it is determined whether or not a value TTCs × Sk obtained by weighting the steering avoidance capability value TTCs by the coefficient Sk is lower than the threshold value TTCb × Bk. When TTCs × Sk is larger than the threshold value TTCb × Bk, steering control is prohibited.
The control command value output means 41 generates a power steering controller output value Outval. The power steering controller output value Outval is a signal indicating the magnitude of the steering torque applied to the steering column 14.
The generation of the power steering controller output value Outval is repeatedly executed at a predetermined cycle.

FIG. 7 is a flowchart of the calculation process performed by the control command value output means 41.
Specifically, as shown in FIG. 7, the control command value output means 41 first determines whether the steering control stop output value Stoff output by the control stop determination means 40 is “0” or “1”. To do. Then, when it is determined that the steering control stop output value Stoff is “0”, the control command value output means 41 sets the steering control output coefficient Contstr to “1” and the torque sensor output coefficient Trqsen to “0”. (Step S1, "No").

Here, the steering control output coefficient Contstr and the torque sensor output coefficient Trqsen are coefficients used for calculating the power steering controller output value Outval, respectively.
Further, when it is determined that the steering control stop output value Stoff is “1”, the control command value output means 41 sets the steering control output coefficient Contstr to “0” and the torque sensor output coefficient Trqsen to “1”. (Step S1, “Yes”). Further, when it is determined that the steering control stop output value Stoff is “1”, information on the steering torque (power steering torque sensor output value) Pssig is acquired from the steering torque sensor 23 (step S2).

Next, the control command value output means 41 acquires the steering control output value Contsig from the actuator control means 36.
Next, based on the steering control output coefficient Contstr, the torque sensor output coefficient Trqsen, the steering control output value Contsig, and the power steering torque sensor output value Pssig, the power steering controller output value Outval is calculated according to the following equation (2) (step S3). .
Outval = Contsig × Contstr + Pssig × Trqsen (2)

  Thus, when the steering control output coefficient Contstr is “1” and the torque sensor output coefficient Trqsen is “0”, the steering control output value Contsig is calculated as the power steering controller output value Outval. That is, the power steering controller output value Outval becomes a steering torque by steering control, that is, a steering torque value that realizes a steering angle that avoids contact between the host vehicle SW and the obstacle SM.

When the steering control output coefficient Contstr is “0” and the torque sensor output coefficient Trqsen is “1”, the torque sensor output coefficient Trqsen is calculated as the power steering controller output value Outval. That is, the power steering controller output value Outval is an auxiliary torque value that reduces the driver's steering torque.
Next, the control command value output means 41 outputs a power steering controller output value Outval (steering command) to the steering control unit 15.

(Operation)
Next, the operation of this embodiment will be described.
First, it is assumed that the driver turns on the main control unit 6 while the vehicle 1 is traveling. Then, the external environment detection means 30 acquires information on the presence / absence of the obstacle SM and information on the travel road area from the external environment detection unit 18. When the acquired information indicates that there is no obstacle SM, the operation of acquiring these information is repeated.
Here, it is assumed that a pedestrian jumps out on the traveling road ahead of the host vehicle SW, and the external environment detection unit 30 detects the obstacle SM as an obstacle SM that obstructs the traveling of the host vehicle SW. Then, the obstacle position detection means 31 acquires information on the obstacle coordinates (St, Sy) and information on the lateral speed Sv of the obstacle SM from the external environment detection unit 18.

When these pieces of information are acquired, the own vehicle state detection means 32 subsequently acquires information about the rotational speeds of the wheels 7FL to 7RR, information about the braking / driving force, and information about the yaw rate Yr. Further, the host vehicle state detection means 32 calculates the host vehicle speed Vc based on the acquired information on the rotational speeds of the wheels 7FL to 7RR.
When the calculation of the host vehicle speed Vc is completed, the host vehicle state detection means 32 acquires information on the throttle opening, information on the depression amount from the brake depression amount sensor 20, and information on the brake fluid pressure. Further, based on the throttle opening information acquired by the own vehicle state detection means 32, the braking / driving forces of the wheels 7FL to 7RR are calculated.

When the calculation of the braking / driving force is finished, the avoidance target point calculation means 33 calculates the avoidance target point based on the host vehicle speed Vc and the obstacle arrival time TTC.
When the calculation of the avoidance target point is completed, the target point arrival time calculating means 34 calculates the target point arrival time TTCm based on the host vehicle speed Vc and the avoidance target point.
When the calculation of the target point arrival time TTCm is finished, the avoidance route calculation means 35 calculates a target steering angle pattern and a target braking force pattern. These calculations are performed based on the host vehicle speed Vc, braking / driving force, yaw rate Yr, and avoidance target point.

FIG. 8 is an explanatory diagram for explaining the target steering angle pattern.
FIG. 9 is an explanatory diagram for explaining a target braking force pattern.
As a result, as the target steering angle pattern, what is steered so that the steering angle is sinusoidal as shown in FIG. 8 is obtained. Further, as a target braking force pattern, as shown in FIG. 9, after a relatively large braking force is generated, the braking force is gradually decreased to obtain a braking force of 0 at the avoidance target point.

When the calculation of the target steering angle pattern and the target braking force pattern is finished, the actuator control means 36 sequentially outputs a braking command to the braking fluid pressure control unit 12. Further, the steering control output value Contsig is sequentially generated.
When the generation of the steering control output value Contsig begins, braking evasion calculating means 37 based on the vehicle speed Vc, calculates a braking evasion value TTCb according control map.

When the calculation of the braking avoidance capability value TTCb is finished, the steering avoidance capability calculating means 38 calculates the steering avoidance capability value TTCs according to the steering control map based on the host vehicle speed Vc.
When the calculation of the steering avoidance capability value TTCs is finished, the avoidance capability comparison means 39 calculates a control stop output Stp based on the braking avoidance capability value TTCb and the steering avoidance capability value TTCs. The control stop output Stp is a parameter used for determining whether to prohibit steering control.

When the calculation of the control stop output Stp is finished, the control stop determination means 40 generates a steering control stop output value Stoff based on the control stop output Stp.
Here, it is assumed that the values of the coefficients Sk and Bk are “1” and the traveling speed of the host vehicle SW is higher than the threshold speed V1. Then, steering avoidance capability value TTCs is a large deal of value than the braking avoidance capability value TTCb, control stop output Stp becomes a value greater than "0". As a result, the value of the steering control stop output value Stoff becomes “0”. That is, the steering control stop output value Stoff is set to a numerical value indicating that steering control is permitted.

When the calculation of the steering control stop output value Stoff is completed, the control command value output means 41 first sets the steering control output coefficient Contstr to “1” and the torque sensor output coefficient Trqsen to “0” based on the steering control stop output value Stoff. " Next, the control command value output means 41 generates a power steering controller output value Outval based on the steering control output coefficient Contstr and the torque sensor output coefficient Trqsen.
Thereby, the power steering controller output value Outval is set to a value that causes the steering angle of the host vehicle SW to follow the target steering angle pattern.
Then, the control command value output means 41 outputs the generated power steering controller output value Outval (steering command) to the steering control unit 15.

FIG. 10 is an explanatory diagram for explaining the actual steering angle and the actual braking force of the host vehicle SW.
And if the brake fluid pressure control part 12 acquires a braking command, it will perform braking control. Then, the brake fluid boosted by the master cylinder 10 is supplied to the wheel cylinders 11FL to 11RR. Further, by supplying the brake fluid pressure to the wheel cylinders 11FL to 11RR, a braking force is generated in each of the wheels 7FL to 7RR as shown in the section A of FIG. As a result, the traveling speed of the host vehicle SW decreases.

Further, the steering control unit 1 5 acquires the steering command, executes the steering control, the steering wheel 13, vehicle SW is steered in a direction away from the obstacle SM. Further, by steering the steering wheel 13, the steered wheels 7FL and 7FR of the host vehicle SW are steered in a direction in which the host vehicle SW moves away from the obstacle SM. Further, by turning the steered wheels 7FL and 7FR, the host vehicle SW is turned in a direction in which the host vehicle SW moves away from the obstacle SM.

When the output of the steering command is completed, a series of the above-described flow is repeatedly executed at a predetermined cycle based on a comparison between the braking avoidance capability value TTCb and the steering avoidance capability value TTCs.
Assume that the host vehicle speed Vc is lower than the threshold speed V1 due to the deceleration of the host vehicle SW while the above flow is repeated. That is, it is assumed that the contact avoidance capability by the steering control is reduced and a relatively large steering torque is applied by the steering control. Then, the steering avoidance capability value TTCs becomes smaller than the braking avoidance capability value TTCb, and the control stop output Stp becomes smaller than “0”. As a result, the steering control stop output value Stoff becomes “1”. That is, the steering control stop output value Stoff is a numerical value indicating prohibition of steering control.

  When the calculation of the steering control stop output value Stoff is completed, the control command value output means 41 first sets the steering control output coefficient Contstr to “0” and the torque sensor output coefficient Trqsen to “1” based on the steering control stop output value Stoff. " Next, the control command value output means 41 generates a power steering controller output value Outval based on the set steering control output coefficient Contstr and torque sensor output coefficient Trqsen.

As a result, the power steering controller output value Outval becomes a value that provides an auxiliary torque that reduces the steering torque of the driver.
Then, the control command value output means 41 outputs the generated power steering controller output value Outval (steering command) to the steering control unit 15.
When the steering control unit 1 5 acquires the steering command, the steering control unit 1 5, a steering control is stopped, and terminates the application of steering torque by the steering control. Thereby, as shown in the section B of FIG. 10, the steering by steering control is complete | finished. Then, an auxiliary torque that reduces the steering torque of the driver is applied to the steering column 14 instead of the steering torque by the steering control.

FIG. 11 is an explanatory diagram for explaining a change state of the steering torque and the steering angle.
Thereby, as shown in the section B of FIG. 11, it is possible to prevent the steering torque from being applied by the steering control in the direction opposite to the steering direction by the driver. Therefore, due to a decrease in the possibility of contact between the host vehicle SW and the obstacle SM, the driving behavior of the driver shifts from a driving operation avoiding the obstacle SM to a driving operation according to the next purpose. The driver never feels uncomfortable.

FIG. 12 is an explanatory diagram for explaining a change state of the steering torque and the steering angle when the steering control and the braking control are always executed.
Compared with the present invention, when the steering control and the braking control are always executed, as shown in FIG. 12, the driver performs the driving operation due to a decrease in the possibility of contact between the host vehicle SW and the obstacle SM. When the above is performed, a relatively large steering torque is applied by the steering control. Therefore, the driver has to apply a larger steering torque (repulsion torque). As a result, the discomfort caused by the mismatch between the driver's steering operation and the steering control becomes greater.

In the present embodiment, the outer field environment detection unit 4 of Figure 1, the laser radar 16, CCD camera 17, external environment detection unit 30 in FIG. 2 constitutes an obstacle detection means. Hereinafter, similarly, the braking force control unit 2, the steering control unit 3, the braking fluid pressure control unit 12, the steering control unit 15, the avoidance path calculation unit 35, the actuator control unit 36, the control stop determination unit 40 in FIG. The control command value output means 41 constitutes an obstacle avoidance means. The steering avoidance ability calculation means 38 in FIG. 2 constitutes a steering avoidance ability estimation means. The braking avoidance capability calculation means 37, the steering avoidance capability calculation means 38, the avoidance capability comparison means 39, and the control stop determination means 40 of FIG. 2 constitute a steering control suppression means. The braking avoidance capability calculation means 37 in FIG. 2 constitutes a braking avoidance capability estimation means. The avoidance capability comparison means 39 of FIG. 2 constitutes a capability comparison determination means. The control stop determination unit 40 in FIG. 2 constitutes a steering control suppression execution unit. The avoidance route calculation means 35 in FIG. 2 constitutes a travel route setting means, and the avoidance route calculation means 35, the actuator control means 36, the control stop determination means 40, and the control command value output means 41 in FIG. The wheel speed sensors 24FL to 24RR in FIG. 1 and the own vehicle state detecting means 32 in FIG. 2 constitute the own vehicle speed detecting means, the steering control map in FIG. 5 constitutes the steering control map, and the steering avoidance capability calculating means in FIG. 38 constitutes a steering estimation means, the braking control map in FIG. 4 constitutes a braking control map, and the braking avoidance capability computing means 37 in FIG. 2 constitutes a braking estimation means.

(Effect of this embodiment)
(1) When the steering avoidance capability is lower than the set threshold value, the steering control suppression means suppresses the steering control for avoiding contact with an obstacle.
For this reason, when the steering avoidance ability becomes lower than the set threshold value and the effect of avoiding contact with an obstacle by the steering control is reduced, the steering control can be suppressed.
As a result, even when the steering control is performed, it is possible to reduce a situation in which the driver feels uncomfortable when the driver performs the steering operation.

(2) A capability comparison determination unit determines whether or not the steering avoidance capability is lower than a set threshold based on the relationship between the steering avoidance capability and the braking avoidance capability. When a determination result that the steering avoidance capability is lower than the braking avoidance capability is obtained, the steering control is suppressed.
For this reason, an appropriate threshold value can be set according to the relationship between the steering avoidance capability and the braking avoidance capability.
As a result, the steering control suppression timing can be made more appropriate.

(3) When the steering avoidance capability is lower than the braking avoidance capability, the obstacle avoidance means determines that the steering avoidance capability is lower than the threshold value. When a determination result is obtained that the steering avoidance capability is lower than the braking avoidance capability, the steering control suppression execution unit suppresses the steering control.
For this reason, when the contact avoidance effect with the obstacle by the braking avoidance ability is larger than the collision avoidance effect with the obstacle by the steering control, the steering control can be suppressed.
As a result, the steering control suppression timing can be made more appropriate.

(4) Even when the host vehicle has not reached the end point of the travel route, if the steering avoidance capability is lower than the braking avoidance capability, the steering control suppression means ends the steering control.
For this reason, for example, the end timing of the steering control can be made more appropriate than that in which the steering control is continued until the host vehicle reaches the end point of the travel path.

(5) The steering estimation means estimates the steering avoidance capability based on the traveling speed of the host vehicle with reference to a steering control map that represents the relationship between the traveling speed of the host vehicle and the steering avoidance capability.
Further, the braking estimation means estimates the braking avoidance capability based on the traveling speed of the host vehicle with reference to a braking control map that represents the relationship between the traveling speed of the host vehicle and the braking avoidance capability.
For this reason, for example, compared with the method of calculating the steering avoidance capability and the avoidance capability in real time based on the vehicle model, the calculation load of the steering avoidance capability and the braking avoidance capability can be reduced.

(6) The ability comparison / determination unit repeatedly determines whether or not the steering avoidance ability is lower than the braking avoidance ability at a predetermined cycle.
For this reason, for example, the end timing of the steering control can be made more appropriate even if the state of the obstacle, the state of the traveling road, and the environmental condition fluctuate.
(7) When the obstacle avoidance means prohibits the steering control, the obstacle avoiding means gives an auxiliary torque to the steering system to reduce the steering torque of the driver instead of the steering torque by the steering control.
For this reason, for example, unlike the method of applying the steering torque for properly ending the steering control to the steering system when the steering control is ended, the calculation load of the steering torque can be reduced.
(Modification)
(1) For example, instead of prohibiting the steering control, the steering torque applied to the steering column 14 by the steering control may be reduced to a fraction of the normal time.

1 is a schematic configuration diagram illustrating a vehicle according to an embodiment of the present invention. 4 is a block flow diagram showing a functional configuration of a main control unit 6. FIG. FIG. 3 is a block diagram showing the configuration of the main control unit 6 in detail. It is explanatory drawing for demonstrating a control map. It is explanatory drawing for demonstrating a steering control map. FIG. 6 is a diagram in which the control maps of FIGS. 4 and 5 are drawn in an overlapping manner. 4 is a flowchart of calculation processing performed by a control command value output means 41. It is explanatory drawing for demonstrating a target steering angle pattern. It is explanatory drawing for demonstrating a target steering angle pattern. It is explanatory drawing for demonstrating the actual steering angle and the actual braking force of the own vehicle SW. It is explanatory drawing for demonstrating the change state of a steering torque and a steering angle. It is explanatory drawing for demonstrating the change state of a steering torque and a steering angle at the time of applying the prior art which always performs steering control and braking control.

Explanation of symbols

1 is a vehicle, 2 is a braking force control unit (obstacle avoidance means), 3 is a steering control unit (obstacle avoidance means), 4 is an external environment detection unit (obstacle detection means), 5 is a vehicle state detection unit, 6 Is a main control unit, 7FL to 7RR are wheels, 8 is a brake pedal, 9 is a booster, 10 is a master cylinder, 11FL to 11RR is a wheel cylinder, 12 is a brake fluid pressure control unit (obstacle avoiding means), and 13 is a steering wheel , 14 is a steering column, 15 is a steering control section (obstacle avoiding means), 16 is a laser radar (obstacle detecting means), 17 is a CCD camera (obstacle detecting means), 18 is an external environment detecting section, and 19 is a throttle. An opening sensor, 20 is a brake depression amount sensor, 21 is a brake fluid pressure sensor, 22 is a steering angle sensor, 23 is a steering torque sensor, and 24FL˜ Reference numeral 24RR denotes a wheel speed sensor (own vehicle speed detection means), 25 denotes a yaw rate sensor, 26 denotes an acceleration sensor, 30 denotes an external environment detection means (obstacle detection means), 31 denotes an obstacle position detection means, and 32 denotes a vehicle state detection means. (Own vehicle speed detection means), 33 is an avoidance target point calculation means, 34 is a target point arrival time calculation means, 35 is an avoidance route calculation means (obstacle avoidance means, travel route setting means, control means), and 36 is an actuator control means. (Obstacle avoiding means, control means), 37 is a braking avoidance ability calculating means (steering control suppressing means, braking avoidance ability estimating means, braking estimating means), and 38 is a steering avoidance ability calculating means (steering avoidance ability estimating means, steering control). 39, avoidance capability comparison means (steering control suppression means, capability comparison determination means), and 40, control stop determination means (obstacle avoidance means, steering control suppression). Stage, the steering control inhibiting execution means, control means), the control instruction value output means 41 (obstacle avoidance means, control means)

Claims (8)

Obstacle detection means for detecting obstacles that obstruct driving of the host vehicle;
Obstacle avoiding means for performing steering control and braking force control on the own vehicle so as to avoid contact between the own vehicle and the obstacle;
Own vehicle speed detecting means for detecting the running speed of the own vehicle;
Steering avoidance ability estimating means for estimating a steering avoidance ability for avoiding contact between the own vehicle and the obstacle by the steering control as the traveling speed of the own vehicle detected by the own vehicle speed detecting means increases .
Brake avoidance capability estimation means for estimating a higher brake avoidance capability for avoiding contact between the host vehicle and the obstacle by the braking force control as the traveling speed of the host vehicle detected by the own vehicle speed detection unit decreases. ,
Steering control suppression means for suppressing the steering control when the steering avoidance capability is lower than the braking avoidance capability;
A vehicle travel support apparatus comprising: 2. The vehicle travel support device according to claim 1 , wherein the steering control suppression unit repeatedly determines whether or not the steering avoidance capability is lower than the braking avoidance capability at a predetermined cycle. The obstacle avoiding means is
Travel route setting means for setting a target travel route of the host vehicle so as to avoid contact between the host vehicle and the obstacle;
Control means for performing the steering control and the braking force control so that the host vehicle travels along the target travel route;
The steering control suppression means, when the determination result that the steering avoidance capability is lower than the braking avoidance capability is obtained even when the host vehicle has not reached the end point of the target travel route, vehicular driving support apparatus according to claim 1 or 2, characterized in that to suppress the steering control. Obstacle detection means for detecting obstacles that obstruct driving of the host vehicle;
Obstacle avoiding means for performing steering control and braking force control on the own vehicle so as to avoid contact between the own vehicle and the obstacle;
Steering avoidance capability estimation means for estimating a steering avoidance capability for avoiding contact between the host vehicle and the obstacle by the steering control;
Braking avoidance capability estimation means for estimating a braking avoidance capability to avoid contact between the host vehicle and the obstacle by the braking force control;
A steering control suppression means for suppressing the steering control based on a comparison result between the steering avoidance capability and the braking avoidance capability,
The obstacle avoiding means is
Travel route setting means for setting a target travel route of the host vehicle so as to avoid contact between the host vehicle and the obstacle;
Control means for performing the steering control and the braking force control so that the host vehicle travels along the target travel route;
The steering control suppression means, when the determination result that the steering avoidance capability is lower than the braking avoidance capability is obtained even when the host vehicle has not reached the end point of the target travel route, Suppress steering control
A vehicle travel support apparatus characterized by the above. Before Symbol steering avoidance capability estimating means,
A steering control map representing the relationship between the traveling speed of the host vehicle and the minimum time required to avoid contact between the host vehicle and the obstacle by the steering control;
Steering estimation means for estimating the steering avoidance capability with reference to the steering control map based on the traveling speed of the host vehicle detected by the host vehicle speed detection means,
The braking avoidance capability estimation means includes
A braking control map representing a relationship between the traveling speed of the host vehicle and the minimum time necessary for avoiding contact between the host vehicle and the obstacle by the braking force control;
The braking estimation means which estimates the said braking avoidance capability with reference to the said braking control map based on the traveling speed of the said own vehicle detected by the said own vehicle speed detection means, The any one of Claim 1 to 4 characterized by the above-mentioned. The vehicle travel support device according to claim 1. The steering control suppression means prohibits the steering control as suppression of the steering control,
The obstacle avoiding means is
When the steering control is executed, a steering torque that realizes a steering angle that avoids contact between the host vehicle and the obstacle is applied to a steering system,
6. The steering system according to claim 1, wherein, when the steering control is prohibited, an auxiliary torque that reduces a driver's steering torque is applied to the steering system in place of the steering torque that realizes the steering angle. The vehicle travel support device according to claim. Obstacle detection means for detecting obstacles that obstruct driving of the host vehicle;
Obstacle avoiding means for performing steering control and braking force control on the own vehicle so as to avoid contact between the own vehicle and the obstacle;
Steering avoidance capability estimation means for estimating a steering avoidance capability for avoiding contact between the host vehicle and the obstacle by the steering control;
Braking avoidance capability estimation means for estimating a braking avoidance capability to avoid contact between the host vehicle and the obstacle by the braking force control;
Steering control suppression means for prohibiting the steering control based on a comparison result between the steering avoidance capability and the braking avoidance capability,
The obstacle avoiding means is
When the steering control is executed, a steering torque that realizes a steering angle that avoids contact between the host vehicle and the obstacle is applied to a steering system,
When the steering control is prohibited, an auxiliary torque that reduces the steering torque of the driver is applied to the steering system instead of the steering torque that realizes the steering angle.
A vehicle travel support apparatus characterized by the above. A vehicle travel support method for performing steering control and braking force control on the host vehicle so as to avoid contact between the host vehicle and an obstacle,
Wherein estimating high steering avoidance ability to avoid contact between the vehicle and the obstacle by the steering control as the vehicle traveling speed becomes higher, said by the braking force control as the vehicle traveling speed becomes lower self A vehicle travel support characterized in that a braking avoidance capability for avoiding contact between a vehicle and the obstacle is highly estimated, and the steering control is suppressed when the estimated steering avoidance capability is lower than the braking avoidance capability. Method.

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