JP7512657B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device, and in particular to a vehicle control device for avoiding a collision between a vehicle and an obstacle.

Conventionally, driving assistance technology (i.e., automatic collision avoidance control) for avoiding collision with an obstacle (e.g., another vehicle) is known (see, for example, Patent Document 1). In automatic collision avoidance control, the need for intervention of an automatic collision avoidance operation (e.g., automatic braking, automatic steering) is determined based on the relationship between the predicted future position of the vehicle and the predicted future position of the obstacle.

In automatic collision avoidance control, the challenge is to prevent unnecessary intervention in automatic collision avoidance operations. For this reason, there is a demand for accurate prediction of the vehicle's future position. In this regard, Patent Document 1 merely describes that the future predicted position is calculated using the vehicle's yaw rate and steering angle, etc., but does not mention how to improve the accuracy of the predicted position.

Patent Document 2 also describes the calculation of the predicted driving path of the vehicle using two calculation methods. That is, a calculation method that uses the current steering angle of the vehicle, and a calculation method that uses the current yaw rate of the vehicle. In Patent Document 2, the predicted driving path obtained by one of the calculation methods is used depending on the magnitude of the current steering angle.

JP 2011-86102 A Japanese Patent Application Laid-Open No. 8-16998

However, as described in Patent Document 2, whether the predicted driving path calculated using the steering angle or the predicted driving path calculated using the yaw rate has higher position accuracy depends on factors other than the steering angle (e.g., bank angle, road surface friction coefficient μ). Therefore, in automatic collision avoidance control, there is still a need to improve the accuracy of the vehicle's future predicted position to prevent unnecessary intervention in the collision avoidance process.

The present invention has been made to solve such problems, and aims to provide a vehicle control device that can suppress unnecessary intervention in collision avoidance processing to avoid collision between the vehicle and an obstacle.

In order to solve the above-mentioned problems, the present invention provides a vehicle control device for avoiding a collision with an obstacle present in the vehicle's direction of travel, which calculates a first predicted driving path having a width through which the vehicle will pass based on a direction of travel predicted from the vehicle's current yaw rate, and calculates a second predicted driving path having a width through which the vehicle will pass based on a direction of travel predicted from the vehicle's current steering angle, and is characterized in that when an obstacle has invaded an overlapping area between the first predicted driving path and the second predicted driving path, and the widthwise intrusion rate of the obstacle into the first predicted driving path is equal to or greater than a first threshold, and the widthwise intrusion rate of the obstacle into the second predicted driving path is equal to or greater than a second threshold different from the first threshold, the device allows the execution of a collision avoidance process.

According to the present invention configured in this way, the overlapping area between the first predicted travel path and the second predicted travel path has a fairly high positional accuracy as an area through which the vehicle will pass in the future, but the outside of the overlapping area is considered to have a low positional accuracy. Therefore, according to the present invention configured in this way, when an obstacle enters the overlapping area with high positional accuracy, the execution of the collision avoidance process is permitted, thereby suppressing unnecessary intervention of the collision avoidance process. Furthermore, according to the present invention configured in this way, the necessity of automatic intervention of the collision avoidance process can be more accurately determined by individually setting a threshold value for the intrusion rate into each predicted travel path.

In the present invention, preferably, the vehicle control device allows the execution of collision avoidance processing when the intrusion rate of the obstacle in the width direction into the overlap area is equal to or greater than a predetermined intrusion threshold. According to the present invention configured in this manner, it is possible to determine whether the obstacle is located in an area of high positional accuracy (overlapping area) within the vehicle's predicted driving path, taking into account the size of the obstacle.

In the present invention, the second threshold value is preferably set to be smaller than the first threshold value. In the present invention, the second predicted driving path based on the steering angle is prone to fluctuating due to structural play in the steering wheel. Therefore, in the present invention, by allowing the execution of collision avoidance processing when the intrusion rate for the second predicted driving path is smaller than the intrusion rate for the first predicted driving path, it is possible to prevent the necessary collision avoidance processing from not being executed due to an erroneous judgment.

In the present invention, the collision avoidance process preferably includes issuing an alarm by a warning device and/or applying a braking force to the vehicle by a braking device.

The vehicle control device of the present invention can suppress unnecessary intervention of automatic collision avoidance operations to avoid collision between the vehicle and an obstacle.

1 is a configuration diagram of a vehicle control device according to an embodiment of the present invention. FIG. 4 is an explanatory diagram of collision determination according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a first predicted travel route according to an embodiment of the present invention. FIG. 11 is an explanatory diagram of a second predicted driving route according to the embodiment of the present invention. 4 is a process flow of automatic collision avoidance control according to an embodiment of the present invention. 4 is a threshold value for automatic collision avoidance control according to an embodiment of the present invention. 4 is an alternative process flow of automatic collision avoidance control according to an embodiment of the present invention. 4 is an alternative process flow of automatic collision avoidance control according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control device according to an embodiment of the present invention will now be described with reference to the accompanying drawings.
First, the configuration of the vehicle control device will be described with reference to Fig. 1. Fig. 1 is a configuration diagram of the vehicle control device.

The vehicle control device 100 of this embodiment is configured to execute automatic collision avoidance control for the vehicle 1 (see FIG. 2, etc.) in which it is mounted. That is, when a collision with an obstacle 3 (see FIG. 2, etc.) present ahead of the vehicle 1 in the traveling direction is predicted, the vehicle control device 100 issues an alarm to the driver and activates the hydraulic brake device to apply a braking force to the vehicle 1.

As shown in FIG. 1, the vehicle control device 100 includes a vehicle control calculation unit (ECU) 10, a number of sensors, and a number of vehicle devices. The number of sensors includes an on-board camera 21, a radar 22, a vehicle speed sensor 23, a yaw rate sensor 24, and a steering angle sensor 25. The number of vehicle devices also includes a brake control system 32 and an alarm device 34.

The ECU 10 is configured as a computer equipped with a processor, memory for storing various programs, input/output devices, etc. The ECU 10 is configured to be able to output operation control signals to the brake control system 32 and the alarm device 34 based on signals received from multiple sensors.

The onboard camera 21 captures images of the surroundings of the vehicle 1 and outputs the captured image data. The ECU 10 identifies attributes of targets (e.g., vehicles, pedestrians, dividing lines (lane boundaries, white lines, yellow lines), obstacles, etc.) based on the image data. The ECU 10 also calculates the distance between the vehicle 1 and the target, the lateral position and relative speed of the target with respect to the vehicle 1, etc. based on the image data. The ECU 10 may also obtain target information from outside via onboard communication equipment, such as through traffic infrastructure or vehicle-to-vehicle communication.

The radar 22 is a millimeter wave radar measurement device that measures the position and speed of a target, transmitting radio waves (transmission waves) ahead of the vehicle 1 and receiving reflected waves that are generated when the transmission waves are reflected by the target. The radar 22 then measures the distance between the vehicle 1 and the target, the relative speed of the target to the vehicle 1, etc., based on the transmission waves and the received waves. Note that in this embodiment, instead of the radar 22, a laser radar, ultrasonic sensor, etc. may be used to measure the distance to the target and the relative speed.

The vehicle speed sensor 23 detects the absolute speed of the vehicle 1 .
The yaw rate sensor 24 detects the yaw rate of the vehicle 1 .
The steering angle sensor 25 detects the rotation angle (steering angle) of the steering wheel of the vehicle 1 .

The brake control system 32 is a controller for controlling the hydraulic brake device of the vehicle 1. When it is necessary to decelerate the vehicle 1, the ECU 10 outputs a brake operation control signal to the brake control system 32 requesting the generation of a braking force on the vehicle 1.

The notification device 34 is a display, indicator light, speaker, etc. provided in the passenger compartment of the vehicle 1, and can generate visual and audible warnings (image display, warning light, warning sound). When there is a possibility of a collision with an obstacle, the ECU 10 outputs an operation control signal to the notification device 34, activating the notification device 34. As a result, the notification device 34 outputs a warning about a collision with an obstacle to the driver.

Next, an overview of the automatic collision avoidance control in the vehicle control device according to this embodiment will be described with reference to Figures 2 to 4. Figure 2 is an explanatory diagram of collision determination, Figure 3 is an explanatory diagram of the first predicted driving route, and Figure 4 is an explanatory diagram of the second predicted driving route.

In automatic collision avoidance control, the ECU 10 calculates two predicted driving routes along which the vehicle 1 will pass. The predicted driving routes are predicted driving areas, i.e., strip-shaped areas along which the vehicle 1 is predicted to pass. The first predicted driving route R1 is calculated based on the vehicle behavior predicted from the current yaw rate φ of the vehicle 1. The second predicted driving route R2 is calculated based on the vehicle behavior predicted from the current steering angle θ of the vehicle 1. Both the first predicted driving route R1 and the second predicted driving route R2 are calculated under the assumption that the current speed V of the vehicle 1 will be maintained.

First, the ECU 10 calculates a first predicted driving route R1 for a predetermined period (e.g., 3 to 5 seconds) based on the current vehicle behavior or vehicle motion (speed V, yaw rate φ) of the vehicle 1. Specifically, the first predicted driving route R1 is based on the assumption that the vehicle 1 maintains the current speed V and travels in a direction predicted from the current yaw rate φ, and is calculated as the area through which the vehicle 1 passes when it makes a steady circular turn on a circular path defined by a turning radius r1 (= V/φ). Thus, the first predicted driving route R1 is a strip-shaped area having a width Wa equivalent to the vehicle width of the vehicle 1. The predicted speed at each position in the traveling direction of the first predicted driving route R1 is set to the current speed V, and each position is set to a position through which the vehicle 1 would pass if it traveled on the circular path at speed V.

Next, the ECU 10 calculates a second predicted driving route R2 for a predetermined period based on the current driving operation state (speed V, steering angle θ) of the vehicle 1. Specifically, the second predicted driving route R2 is based on the assumption that the vehicle 1 maintains the current speed V and travels in a direction predicted from the current steering angle θ, and is calculated as an area through which the vehicle 1 passes when the vehicle 1 makes a steady circular turn on an arc path defined by a turning radius r2. Thus, the second predicted driving route R2 is a band-shaped area having a width Wa equivalent to the vehicle width of the vehicle 1, similar to the first predicted driving route R1. The turning radius r2 is expressed by the following formula.
r2=N·L·(1+K·V ² )/θ

Here, N is the steering gear ratio, L is the wheelbase (m), and K is the stability factor. The stability factor is an index of how easily the vehicle 1 turns, and depends on the friction coefficient of the road surface, etc. In this embodiment, the stability factor is set to a predetermined value (fixed value), but it may also be a variable value that varies depending on the road surface conditions, etc.

The second predicted driving route R2, which is set based on the driving operation state (specifically, the steering angle θ), is prone to change over time due to minute rotational movements caused by the structural play of the steering wheel. On the other hand, the first predicted driving route R1, which is set based on the vehicle behavior (yaw rate φ), is less likely to change over time than the second predicted driving route R2 because the vehicle behavior is less likely to change over time than the steering wheel. Therefore, in this embodiment, the first predicted driving route R1 is treated as the main predicted driving route, and the second predicted driving route R2 is treated as the secondary predicted driving route.

As shown in FIG. 2, the first predicted driving route R1 and the second predicted driving route R2 usually do not completely match, but have an overlapping area R0 where they overlap. In FIG. 2, an obstacle 3 (e.g., another vehicle) is detected ahead of the vehicle 1 in the traveling direction, and a part of the obstacle 3 is in the overlapping area R0. In the automatic collision avoidance control of this embodiment, if at least a part of the obstacle 3 is located in the overlapping area R0, it is determined that there is a possibility of a collision between the vehicle 1 and the obstacle 3.

As shown in FIG. 2, the ECU 10 calculates the overlap rate F0 (intrusion rate) of the obstacle 3 in the width direction relative to the overlap region R0. To this end, the ECU 10 calculates the width Wb of the obstacle 3 based on image data from the vehicle-mounted camera 21, and calculates the intrusion length W0 of the obstacle 3 that has intruded into the overlap region R0. The ECU 10 calculates the overlap rate F0 (= W0/Wb) based on the acquired Wb and W0.

Furthermore, as shown in FIG. 3, the ECU 10 calculates the overlap rate F1 (intrusion rate) of the obstacle 3 in the width direction relative to the first predicted driving route R1. To this end, the ECU 10 calculates the intrusion length W1 of the obstacle 3 that has intruded into the first predicted driving route R1 based on image data from the vehicle-mounted camera 21. The ECU 10 calculates the overlap rate F1 (= W1/Wb) based on the acquired Wb and W1.

The ECU 10 also determines the overlap rate F2 (intrusion rate) of the obstacle 3 in the width direction relative to the second predicted driving route R2, as shown in FIG. 4. To this end, the ECU 10 calculates the intrusion length W2 of the obstacle 3 that has intruded into the second predicted driving route R2 based on image data from the onboard camera 21. The ECU 10 calculates the overlap rate F2 (= W2/Wb) based on the acquired Wb and W2.

When the obstacle 3 is located in the overlap region R0, the possibility of the vehicle 1 colliding with the obstacle 3 increases. In this embodiment, under the condition that the obstacle 3 is located in the overlap region R0, if the overlap rates F1 and F2 each satisfy a predetermined condition, the execution of the collision avoidance process is permitted (standby state). Specifically, if the overlap rates F0, F1, and F2 are equal to or greater than predetermined threshold values S0, S1, and S2, respectively, the execution of the collision avoidance process is permitted. Then, in this embodiment, in a state in which the execution of the collision avoidance process is permitted, the collision avoidance process is executed when the time to collision TTC falls below a predetermined threshold time (T1, T2).

In this manner, in this embodiment, the presence of an obstacle 3 in the overlapping area R0 of two predicted driving routes calculated using different methods is one of the conditions for executing the collision avoidance process. This makes it possible to prevent the automatic collision avoidance process from being erroneously executed in a state where there is no collision with the obstacle 3.

In this embodiment, the automatic collision avoidance control is configured to sequentially execute multiple collision avoidance processes (first, second, and third collision avoidance processes). The multiple collision avoidance processes include the generation of an alarm by the alarm device 34 (alarm process) and the application of a braking force to the vehicle 1 by the brake control system 32 (emergency automatic braking process). The emergency automatic braking process includes a primary braking process for applying a predetermined deceleration, and a secondary braking process for applying an even greater deceleration than the primary braking process. For example, the deceleration of the primary braking process is set to a magnitude that stops the vehicle 1 within 1.6 seconds, and the deceleration of the secondary braking process is set to a magnitude that stops the vehicle 1 within 1.0 second.

The first collision avoidance process is only a preliminary warning process, and is executed when the time to collision TTC reaches a predetermined threshold time (e.g., 2.4 seconds). In the preliminary warning process, the driver is notified that there is a risk of collision. The second collision avoidance process is a primary braking process and a primary warning process, and is executed when the time to collision TTC reaches a predetermined threshold time (e.g., 1.6 seconds). In the primary warning process, a notification is issued that a preliminary brake will be applied to avoid a collision. The third collision avoidance process is a secondary braking process and a secondary warning process, and is executed when the time to collision TTC reaches a predetermined threshold time (e.g., 1.0 second). In the secondary warning process, a notification is issued that a final brake will be applied to avoid a collision.

As described above, these multiple collision avoidance processes are executed according to the time to collision (TTC). A different threshold time for the TTC is set for each collision avoidance process. The time to collision (TTC) is calculated by dividing the distance D between the vehicle 1 and the target (obstacle 3) by the relative speed Vr of the vehicle 1 with respect to the target (TTC=D/Vr).

As a collision avoidance process, in addition to or instead of the primary braking process and the secondary braking process, steering process may be automatically intervened in the vehicle 1 to avoid a collision with the obstacle 3.

Next, the process flow of the automatic collision avoidance control in the vehicle control device 100 of this embodiment will be described with reference to Figures 5 and 6. Figure 5 shows the process flow of the automatic collision avoidance control, and Figure 6 shows the threshold value of the automatic collision avoidance control.

The ECU 10 repeatedly executes the process flow of FIG. 5 at predetermined time intervals (e.g., 0.1 seconds). First, the ECU 10 executes a sensor information acquisition process (S101). In the sensor information acquisition process, the ECU 10 acquires sensor information from the vehicle-mounted camera 21, radar 22, vehicle speed sensor 23, yaw rate sensor 24, steering angle sensor 25, etc.

Next, the ECU 10 executes a vehicle information acquisition process (S102) using various information acquired in the sensor information acquisition process (S101). In the vehicle information acquisition process, the ECU 10 acquires the speed V, yaw rate φ, steering angle θ, etc. of the vehicle 1, as well as target information regarding targets present around and in the area ahead of the vehicle 1. The target information includes the target's attributes, position (longitudinal position, lateral position, and distance relative to the vehicle 1), relative speed, dimensions (particularly the target's width), etc. In addition, the ECU 10 acquires other data (steering gear ratio, wheelbase, stability factor, etc.) from memory or other control devices.

Next, the ECU 10 calculates a first predicted driving route R1 and a second predicted driving route R2 based on the acquired vehicle information (S103), and calculates an overlapping area R0 between the first predicted driving route R1 and the second predicted driving route R2 (S104). Furthermore, if a target (obstacle 3 in FIG. 2) is present within the overlapping area R0, the ECU 10 calculates an overlapping rate F0 and determines whether the overlapping rate F0 is equal to or greater than a predetermined threshold value S0 (S105). In this embodiment, the threshold value S0 is 0.2 (20%).

If the overlap rate F0 is less than the threshold value S0 (S105: No, F0<S0), the ECU 10 ends the process. Therefore, if an obstacle 3 is not detected, or if an obstacle 3 is detected but the overlap rate F0 is less than the threshold value S0, the likelihood of a collision is low, so the ECU 10 ends the process. Alternatively, the threshold value S0 may be a positive number that is approximately zero. In other words, this process flow may be configured so that if at least a portion of the target is located within the overlap region R0 in step S105 (if F0 is positive), step S106 is performed.

On the other hand, if the overlap rate F0 is equal to or greater than the threshold value S0 (S105: Yes, F0≧S0), the ECU 10 calculates the overlap rate F1 and determines whether the overlap rate F1 is equal to or greater than a predetermined threshold value S1 (S106). In this embodiment, the threshold value S1 is 0.34 (34%). If the overlap rate F1 is less than the threshold value S1 (S106: No, F1<S1), the ECU 10 ends the process.

On the other hand, if the overlap rate F1 is equal to or greater than the threshold value S1 (S106: Yes, F1≧S1), the ECU 10 calculates the overlap rate F2 and performs a determination process to determine which of the first to third collision avoidance processes to perform based on the calculated overlap rate F2.

First, the case where the overlap rate F2 is equal to or greater than the threshold value S2a (S107: Yes, F2≧S2a) will be described. In this embodiment, the threshold value S2a is 0.30 (30%). In this case, the ECU 10 determines which of the first to third collision avoidance processes to execute depending on the TTC (S109, S113, S117). That is, when the TTC becomes equal to or less than the threshold value T1a for the secondary brake process (S109: Yes, TTC≦T1a), the ECU 10 executes the third collision avoidance process (S110) and ends the process. In the third collision avoidance process, the ECU 10 outputs a brake operation control signal to the brake control system 32 to execute the secondary brake process, and outputs an operation control signal to the alarm device 34 to execute the secondary warning process. In this embodiment, the threshold value T1a is 1.0 (seconds).

Also, when the TTC is greater than the threshold T1a but is equal to or less than the threshold T1b for the primary brake processing (S113: Yes, T1a<TTC≦T1b), the ECU 10 executes the second collision avoidance processing (S114) and ends the processing. In the second collision avoidance processing, the ECU 10 outputs a brake operation control signal to the brake control system 32 to execute the primary brake processing, and outputs an operation control signal to the alarm device 34 to execute the primary warning processing. In this embodiment, the threshold T1b is 1.6 (seconds).

Also, when the TTC is greater than the threshold T1b but is equal to or less than the threshold T1c for the secondary brake processing (S117: Yes, T1b<TTC≦T1c), the ECU 10 executes the first collision avoidance processing (S118) and ends the processing. In the first collision avoidance processing, the ECU 10 outputs an operation control signal to the alarm device 34 to execute a preliminary warning processing. In this embodiment, the threshold T1c is 2.4 (seconds).

Also, if TTC is greater than the threshold value T1c (S117: No, T1c<TTC), the ECU 10 ends the process. In this case, the target (obstacle 3) is far away from the vehicle 1, so collision avoidance processing is not executed.

Next, the case where the overlap rate F2 is equal to or greater than the threshold value S2b and less than S2a (S107: No, S111: Yes, S2b≦F2<S2a) will be described. In this embodiment, the threshold value S2b is 0.20 (20%). In this case, the ECU 10 determines which of the first and second collision avoidance processes to execute according to the TTC (S113, S117). That is, since the target (obstacle 3) overlaps with the first predicted driving route R1 at an intrusion rate equal to or greater than the threshold value S1 (S106: Yes), there is a possibility of a collision, but since the target overlaps with the second predicted driving route R2 only at an intrusion rate in the range of the threshold values S2b to S2a (S107: No), a determination is made as to whether to execute only the first and second collision avoidance processes.

As described above, the steering angle θ is prone to change over time, and therefore the second predicted driving path R2 is also prone to change. Thus, the farther the obstacle 3 is located, the more likely the overlap rate F2 is to change. For this reason, in this embodiment, even if the overlap rate F2 is less than the threshold value S2a (S107: No), the execution of a collision avoidance process with a longer threshold time (in this case, the first and second collision avoidance processes) is permitted, thereby preventing the necessary collision avoidance process from not being executed due to an erroneous judgment.

Specifically, when the TTC becomes equal to or less than the threshold value T1b (S113: Yes, TTC≦T1b), the ECU 10 executes the second collision avoidance process (S114) and ends the process. On the other hand, when the TTC is greater than the threshold value T1b but equal to or less than the threshold value T1c (S117: Yes, T1b<TTC≦T1c), the ECU 10 executes the first collision avoidance process (S118) and ends the process. On the other hand, when the TTC is greater than the threshold value T1c (S117: No, T1c<TTC), the ECU 10 ends the process.

Next, the case where the overlap rate F2 is equal to or greater than the threshold value S2c and less than S2b (S107: No, S111: No, S115: Yes, S2c≦F2<S2b) will be described. In this embodiment, the threshold value S2c is 0.20 (20%), which is the same as the threshold value S2b. However, alternatively, the threshold value S2c may be a value smaller than the threshold value S2b (for example, 0.15). In this case, the ECU 10 determines whether to execute the first collision avoidance process according to the TTC (S117). That is, since the target (obstacle 3) overlaps with the first predicted driving route R1 at an intrusion rate equal to or greater than the threshold value S1 (S106: Yes), there is a possibility of a collision, but since the target overlaps with the second predicted driving route R2 only at an intrusion rate in the range of the threshold values S2c to S2b (S111: No), a determination is made as to whether to execute only the first collision avoidance process.

In this embodiment, even if the overlap rate F2 is less than the threshold value S2b (S111: No), the execution of a collision avoidance process with a longer threshold time (in this case, the first collision avoidance process) is permitted, thereby preventing the necessary collision avoidance process from not being executed due to an erroneous judgment.

Specifically, when the TTC becomes equal to or less than the threshold value T1c (S117: Yes, TTC≦T1c), the ECU 10 executes the first collision avoidance process (S118) and ends the process. On the other hand, when the TTC is greater than the threshold value T1c (S117: No, T1c<TTC), the ECU 10 ends the process.

In this embodiment, it is assumed that the position accuracy of the first predicted driving path R1 calculated based on the current vehicle behavior (yaw rate φ) of the vehicle 1 is higher than the position accuracy of the second predicted driving path R2 calculated based on the current driving operation state (steering angle θ) of the vehicle 1. Therefore, under the condition that the obstacle 3 overlaps with the overlapping region R0, the first to third collision avoidance processes are executed only when the overlap rate F1 is high (F1≧S1). The overlap rate F2 is used to determine which collision avoidance process is executed. Specifically, the higher the overlap rate F2, the higher the collision avoidance process is executed. That is, the higher the overlap rates F1 and F2 are (or the smaller the difference between them), the higher the accuracy of the future predicted position of the vehicle (i.e., the position accuracy of the first and second predicted driving paths). As a result, in this embodiment, when it is determined that the position accuracy is higher, the first to third collision avoidance processes are executed, so that unnecessary intervention of the automatic collision avoidance process can be suppressed.

Next, an alternative processing flow of the automatic collision avoidance control in the vehicle control device 100 of this embodiment will be described with reference to Figures 7A, 7B, and 6. Figures 7A and 7B show an alternative processing flow of the automatic collision avoidance control. The vehicle control device 100 can use the alternative processing flow shown in Figures 7A and 7B instead of the processing flow in Figure 5.

In the process flow of FIG. 5, if the overlap rate F1 is smaller than the threshold value S1 (S106: No), none of the collision avoidance processes are executed. On the other hand, in the alternative process flow, even if the overlap rate F1 is smaller than the threshold value S1 (S206: No), one of the collision avoidance processes is executed depending on the situation. Also, in the process flow of FIG. 5, if the overlap rate F2 is smaller than the threshold value S2c (S115: No), the process is terminated. On the other hand, in the alternative process flow, even if the overlap rate F2 is smaller than the threshold value S2c (S215: No), one of the collision avoidance processes is executed depending on the situation. Note that steps S201 to S218 shown in FIG. 7A are the same as steps S101 to S118 in FIG. 5, so a description thereof will be omitted.

In step S206, if the overlap rate F1 is smaller than the threshold value S1 (S206: No), the ECU 10 calculates the overlap rate F2 and performs a determination process to determine which of the first to third collision avoidance processes to perform based on the calculated overlap rate F2.

First, the case where the overlap rate F2 is equal to or greater than the threshold value S2a (S219: Yes, F2≧S2a) will be described. In this case, it is determined which of the first to third collision avoidance processes is to be executed according to the TTC (S221, S225, S229). That is, when the TTC becomes equal to or less than the threshold value T2a for the secondary brake process (S221: Yes, TTC≦T2a), the third collision avoidance process is executed (S222). When the TTC is greater than the threshold value T2a but equal to or less than the threshold value T2b (S225: Yes, T2a<TTC≦T2b), the second collision avoidance process is executed (S226). When the TTC is greater than the threshold value T2b but equal to or less than the threshold value T2c (S229: Yes, T2b<TTC≦T2c), the first collision avoidance process is executed (S230). Also, if TTC is greater than the threshold T2c (S229: No, T2c < TTC), the process ends.

Note that threshold T2a is set to 0.8 (seconds), which is smaller than threshold T1a, threshold T2b is set to 1.4 (seconds), which is smaller than threshold T1b, and threshold T2c is set to 2.2 (seconds), which is smaller than threshold T1c.

Therefore, in an alternative embodiment, when the overlap rate F1 is low (S206: No), the first to third collision avoidance processes are executed at a later timing than when the overlap rate F1 is high (S206: Yes). This makes it possible to suppress unnecessary intervention of the automatic collision process when the future position accuracy of the vehicle 1 is considered to be relatively low (S206: No).

Next, the case where the overlap rate F2 is equal to or greater than the threshold value S2b but less than S2a (S219: No, S223: Yes, S2b≦F2<S2a) will be described. In this case, it is determined which of the first and second collision avoidance processes is to be executed according to the TTC (S225, S229). Specifically, when the TTC is equal to or less than the threshold value T2b (S225: Yes, TTC≦T2b), the second collision avoidance process is executed (S226). On the other hand, when the TTC is greater than the threshold value T2b but less than or equal to the threshold value T2c (S229: Yes, T2b<TTC≦T2c), the first collision avoidance process is executed (S230). Also, when the TTC is greater than the threshold value T2c (S229: No, T2c<TTC), the process is terminated.

Next, the case where the overlap rate F2 is equal to or greater than the threshold value S2c but less than S2b (S219: No, S223: No, S227: Yes, S2c≦F2<S2b) will be described. In this case, it is determined whether or not to execute the first collision avoidance process depending on the TTC (S229). Specifically, when the TTC becomes equal to or less than the threshold value T2c (S229: Yes, TTC≦T2c), the first collision avoidance process is executed (S230). On the other hand, when the TTC is greater than the threshold value T2c (S229: No, T2c<TTC), the process is terminated.

In the alternative embodiment shown in Figures 7A and 7B, under conditions where an obstacle 3 overlaps with the overlap region R0, even if the overlap rate F1 for the first predicted driving route R1, which is considered to be more reliable, is small (S206: No), the operation timing may be delayed and the first to third collision avoidance processes may be executed. This makes it possible to suppress unnecessary intervention of the automatic collision avoidance process while ensuring safety in the alternative embodiment.

Next, the operation of the vehicle control device 100 in this embodiment will be described. In this embodiment, the vehicle control device 100 for avoiding a collision with an obstacle 3 present in the traveling direction of the vehicle 1 calculates a first predicted driving route R1 having a width Wa through which the vehicle 1 will pass based on the traveling direction predicted from the current yaw rate φ of the vehicle 1, calculates a second predicted driving route R2 having a width Wa through which the vehicle 1 will pass based on the traveling direction predicted from the current steering angle θ of the vehicle 1, and allows the execution of a collision avoidance process if the obstacle 3 enters an overlapping area R0 between the first predicted driving route R1 and the second predicted driving route R2.

In this embodiment, the overlapping area R0 between the first predicted driving route R1 and the second predicted driving route R2 has a fairly high degree of positional accuracy as an area through which the vehicle 1 will pass in the future, but the area outside the overlapping area R0 is considered to have a lower degree of positional accuracy. Therefore, in this embodiment configured in this manner, when an obstacle 3 enters the overlapping area R0, which has a high positional accuracy, unnecessary intervention in the collision avoidance process can be suppressed by allowing the collision avoidance process to be executed.

In addition, in this embodiment, the vehicle control device 100 allows the execution of collision avoidance processing when the widthwise overlap rate F0 of the obstacle 3 in the overlap region R0 is equal to or greater than a predetermined intrusion threshold S0. In this embodiment, which is configured in this manner, the size of the obstacle 3 is taken into consideration to determine whether or not it is located within an area of high positional accuracy (overlapping region R0) within the predicted driving path of the vehicle 1.

In addition, in this embodiment, the vehicle control device 100 allows the execution of collision avoidance processing when the widthwise overlap rate F1 of the obstacle 3 on the first predicted driving route R1 is equal to or greater than the first threshold value S1, and the widthwise overlap rate F2 of the obstacle 3 on the second predicted driving route R2 is equal to or greater than a second threshold value S2 (S2a-S2c) different from the first threshold value S1. In this embodiment, which is configured in this manner, the necessity for automatic intervention in the collision avoidance processing can be more accurately determined by setting individual threshold values for the overlap rates (F1, F2) on each predicted driving route (R1, R2).

In addition, in this embodiment, the second threshold value S2 (S2a-S2c) is set smaller than the first threshold value S1. In this embodiment, the second predicted driving path R2 based on the steering angle θ is prone to fluctuation due to structural play in the steering wheel. Therefore, in this embodiment, by allowing the execution of collision avoidance processing when the overlap rate F2 with respect to the second predicted driving path R2 is smaller than the overlap rate F1 with respect to the first predicted driving path R1, it is possible to prevent the necessary collision avoidance processing from not being executed due to an erroneous judgment.

In this embodiment, the collision avoidance process includes multiple collision avoidance processes (first to third collision avoidance processes) with different activation times, and the second threshold S2 (S2a-S2c) is set for each of the multiple collision avoidance processes, with the second threshold set smaller for collision avoidance processes with earlier activation times. In this embodiment, due to the steering angle θ, which is prone to fluctuation, the position accuracy of the second predicted driving path R2 decreases the farther away from the vehicle 1. Therefore, the accuracy of the overlap rate F2 with the second predicted driving path R2 for a distant obstacle 3 is lower than the accuracy of the overlap rate F2 with a nearby obstacle 3. Therefore, in this embodiment, for collision avoidance processes with earlier activation times, execution is permitted even if the overlap rate F2 with the second predicted driving path R2 is relatively small, thereby preventing necessary collision avoidance processes from not being executed due to erroneous judgment.

In addition, in this embodiment, the collision avoidance process includes issuing an alarm by the alarm device 34 and/or applying a braking force to the vehicle 1 by the brake device.

1 vehicle 3 obstacle 10 ECU
100 Vehicle control device R0 Overlap area R1 First predicted driving route R2 Second predicted driving route Wa Width Wb Width

Claims (4)

A vehicle control device for avoiding a collision with an obstacle present in a traveling direction of a vehicle,
Calculating a first predicted driving path having a width through which the vehicle will pass, based on a traveling direction predicted from a current yaw rate of the vehicle;
calculating a second predicted driving route having the width along which the vehicle will travel, based on a traveling direction predicted from a current steering angle of the vehicle;
A vehicle control device that allows the execution of a collision avoidance process when the obstacle has entered an overlapping area between the first predicted driving path and the second predicted driving path, and when the widthwise intrusion rate of the obstacle into the first predicted driving path is greater than or equal to a first threshold, and when the widthwise intrusion rate of the obstacle into the second predicted driving path is greater than or equal to a second threshold different from the first threshold. 2. The vehicle control device according to claim 1, wherein the obstacle intrudes into an overlapping area between the first predicted driving route and the second predicted driving route when a widthwise intrusion rate of the obstacle into the overlapping area is equal to or greater than a predetermined intrusion threshold. The vehicle control device according to claim 1 or 2, wherein the second threshold value is set to be smaller than the first threshold value. The vehicle control device according to claim 1 , wherein the collision avoidance process includes issuing an alarm by an alarm device and/or applying a braking force to the vehicle by a brake device.

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