JP2006256478A - Traveling control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely generate a brake pre-load when a vehicle traveling on an adjacent lane approaches an own vehicle lane by receiving influence of side wind or a cant road surface. <P>SOLUTION: When lateral acceleration of the own vehicle is generated, it is determined that the own vehicle receives side wind or travels on the cant road surface. When the vehicle traveling on the adjacent lane is detected in front of the own vehicle in the opposite direction to a generating direction of the lateral acceleration, it is determined that there is large possibility that the adjacent vehicle approaches the own lane by receiving the side wind or a cant, and a brake pre-load is generated. If a driver operates a brake pedal when the adjacent vehicle comes to ahead of the own vehicle, braking force is immediately generated. The responsivity to brake operation is improved, and an idle running distance can be shortened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a travel control device that generates a brake preload according to a travel environment.

  There is known a travel control device that generates brake preload when the distance between the vehicle and the preceding vehicle is shortened or when the deceleration is low so as to reduce the responsiveness to the brake operation and the idling distance ( For example, see Patent Document 1).

Prior art documents related to the invention of this application include the following.
JP 2000-309257 A

  However, in the above-described conventional traveling control device, even if a vehicle traveling in an adjacent lane approaches the own lane due to the influence of crosswinds or a cant road surface, no brake preload is generated until the vehicle is in front of the vehicle. There is a problem that the brake preload cannot be generated accurately according to the environment.

  When a lateral acceleration is generated in the lateral direction of the host vehicle and a vehicle traveling in the adjacent lane is detected in front of the host vehicle in a direction opposite to the lateral acceleration generation direction, a brake preload is generated.

  According to the present invention, it is possible to accurately generate the brake preload according to the traveling environment, improve the responsiveness to the brake operation, and shorten the idling distance.

When a preceding vehicle is detected on the own lane, the preceding vehicle is controlled by controlling the inter-vehicle distance so that the inter-vehicle distance to the preceding vehicle becomes the target inter-vehicle distance with the preset vehicle speed (hereinafter referred to as the set vehicle speed) as the upper limit. An embodiment applied to a preceding vehicle following traveling control apparatus that performs vehicle speed control and travels at a constant speed at a set vehicle speed when the preceding vehicle is not detected on the own lane will be described.
In addition to the preceding vehicle following travel control device, the present invention can also be applied to a constant speed travel control device that travels at a constant speed, for example, at a preset vehicle speed (set vehicle speed).

  FIG. 1 is a diagram showing a configuration of an embodiment. The inter-vehicle distance radar 1 scans a laser beam in front of the vehicle to detect a preceding vehicle on its own lane, and measures an inter-vehicle distance L to the preceding vehicle. In addition, it is good also as a millimeter wave inter-vehicle distance radar using a millimeter wave instead of a laser beam. The vehicle speed sensor 2 detects the host vehicle speed V. The main switch 3 is an operating member for operating the preceding vehicle follow-up travel control device. When the main switch 3 is turned on, the power is supplied to the preceding vehicle follow-up travel control device and the operation state is entered.

  The resume / accelerate switch 4 reads the set vehicle speed at the time of the preceding preceding vehicle following traveling control when the preceding vehicle following traveling control is not being performed, and resumes the preceding vehicle following traveling control. It is an operating member that increases the set vehicle speed of the high-speed running control. The cancel switch 5 is an operation member for canceling the preceding vehicle following traveling control.

  The set / coast switch 6 is an operation member that starts the preceding vehicle following traveling control when the preceding vehicle following traveling control is not being performed, and reduces the set vehicle speed of the constant speed traveling control when the preceding vehicle following traveling control is being performed. When the preceding vehicle follow-up running control is started by operating the set / coast switch 6 when the preceding vehicle follow-up running control is not in progress, the preceding vehicle follow-up running control is started if a preceding vehicle is detected on the own lane, If no preceding vehicle is detected on the own lane, constant speed running control is started with the vehicle speed at that time as the set vehicle speed.

  The brake switch 7 is a switch that is turned on when a brake pedal (not shown) is depressed, and the lateral acceleration sensor 9 is a sensor that detects a lateral acceleration G that occurs in the lateral direction (vehicle width direction) of the host vehicle. The camera 9 images the road situation ahead of the vehicle. The image processing device 9a processes the image captured by the camera 9 and detects the vehicle traveling in the adjacent lane ahead of the host vehicle and the vehicle height H.

  The travel control controller 10 includes a CPU 10a, a ROM 10b, a RAM 10c, and the like, performs the preceding vehicle following travel control and the constant speed travel control, and executes a control program described later to perform brake preload control. The engine control device 11 performs intake air amount control, fuel injection control, ignition timing control, and the like of an engine (not shown) to adjust the output torque and rotation speed of the engine and control the driving force of the vehicle. The transmission control device 12 controls a transmission ratio of an automatic transmission (not shown), that is, a shift position.

  The brake control device 13 controls the braking force of the vehicle by adjusting the brake fluid pressure. The brake control device 13 generates a “brake preload” Ppre set in advance when a brake preload command is received from the travel control controller 10. The brake preload Ppre is a brake hydraulic pressure for generating a braking force from the time when the driver starts to depress the brake pedal without the “play” of the brake pad. The brake fluid pressure for generating braking force immediately after the driver starts to depress the brake pedal without completely playing the brake pads is defined as the maximum brake preload Ppre_max. It can be controlled to any hydraulic pressure in between.

  In this embodiment, when the lateral acceleration G is generated in the own vehicle, it is determined that the own vehicle is receiving a side wind or is traveling on a cant road surface, and the lateral acceleration G is generated in the own vehicle. If there is a vehicle traveling in the adjacent lane in front of the vehicle, it is determined that the adjacent vehicle is likely to approach or enter the lane under the influence of crosswinds or cant roads, and brake preload Is generated automatically.

  The navigation device 14 detects the current location of the vehicle and provides information such as the legal speed of the traveling road. The VICS receiver 15 receives traffic jam information by an optical beacon, a radio wave beacon, FM multiplex broadcasting, or the like. The display device 16 displays the control state of the preceding vehicle follow-up travel control device and the travel state of the vehicle.

  FIG. 2 is a flowchart showing a brake preload control program according to an embodiment. The travel controller 10 repeatedly executes this brake preload control program every predetermined time (for example, 10 msec) while an ignition switch (not shown) is turned on.

  In step 1, it is determined whether or not the absolute value of the lateral acceleration G is equal to or less than a preset threshold value GL. Note that the value of the threshold value GL is determined based on the necessity of brake preload, and avoids unnecessary brake preload at low lateral acceleration. If the absolute value of the lateral acceleration G is equal to or less than the threshold value GL, it is determined that it is not necessary to generate the brake preload, and the process proceeds to step 9 to check whether the brake preload is being generated. When the absolute value of the lateral acceleration G becomes equal to or less than the threshold value GL during the generation of the brake preload, the process proceeds to step 10, and the brake preload is released after a predetermined time (for example, 10 seconds). On the other hand, if the brake preload is not being generated, the process is terminated.

  When the absolute value of the lateral acceleration G is larger than the threshold value GL, the process proceeds to step 2, and based on the processing result of the captured image in front of the host vehicle, the adjacent lane is set ahead of the host vehicle in the direction opposite to the direction of occurrence of the lateral acceleration. It is confirmed whether or not there is a traveling vehicle (hereinafter simply referred to as an adjacent vehicle). The generation direction of the lateral acceleration can be determined by the sign of the output of the lateral acceleration sensor 8. If there is no vehicle traveling in the adjacent lane ahead of the host vehicle in the direction opposite to the direction in which the lateral acceleration is generated, it is determined that it is not necessary to generate the brake preload, and the brake preload is applied as described above in steps 9 and 10. If the brake preload is being generated, the brake preload is released after a predetermined time. If the brake preload is not being generated, the process is terminated.

  If the absolute value of the lateral acceleration G is greater than the threshold value GL and there is a vehicle traveling in the adjacent lane ahead of the host vehicle in the direction opposite to the direction in which the lateral acceleration is generated, the process proceeds to step 3 and the subsequent steps. Is generated. First, in step 3, it is determined whether or not the absolute value of the lateral acceleration G exceeds a preset threshold value GH. The threshold value GH is determined based on the necessity of canceling the preceding vehicle follow-up travel control and the constant speed travel control. When a large lateral acceleration is generated, the travel control is canceled and the operation is switched to the manual operation. . When the absolute value of the lateral acceleration G exceeds the threshold value GH, the routine proceeds to step 7, where the preceding vehicle following traveling control and the constant speed traveling control are canceled, and the cancellation of the traveling control is warned by sound and display. In step 8, the maximum brake preload Ppre_max is generated.

  If the absolute value of the lateral acceleration G is less than or equal to the threshold GH, the process proceeds to step 4 to determine whether or not the vehicle height H of the vehicle traveling in the adjacent lane exceeds a preset threshold Ho. Note that the value of the threshold Ho is determined based on the necessity of canceling the preceding vehicle following traveling control and the constant speed traveling control, and the vehicle travels when a vehicle having a large vehicle height is traveling in the adjacent lane ahead of the host vehicle. Release control and switch to manual operation. When the vehicle height H of the adjacent vehicle exceeds the threshold value Ho, the process proceeds to step 7 where the preceding vehicle follow-up running control and the constant speed running control are released, and the release of the running control is warned by voice and display. In step 8, the maximum brake preload Ppre_max is generated.

  If the absolute value of the lateral acceleration G is less than or equal to the threshold value GH and the vehicle height H of the adjacent vehicle is less than or equal to the threshold value Ho, the process proceeds to step 5, and the absolute value of the lateral acceleration G, the vehicle height H of the adjacent vehicle, A brake preload value is determined based on the vehicle speed V.

  First, as shown in FIG. 3, the brake preload Ppre is set to a larger value as the amount by which the absolute value of the lateral acceleration G exceeds the threshold value GL is larger. As shown by the solid line a in FIG. 3, a certain value may be set for the brake preload Ppre at the threshold value GL, or as shown by the broken line b, the brake preload Ppre at the threshold value GL is set to a certain value. It may be 0. When the brake preload Ppre reaches the above-mentioned maximum value Ppre_max, the maximum brake preload Ppre_max is constant even if the absolute value of the lateral acceleration G increases further. Further, as indicated by a dashed line c in FIG. 3, when the absolute value of the lateral acceleration G exceeds the threshold value GL, the maximum brake preload Ppre_max may be generated regardless of the threshold excess amount.

  The larger the absolute value of the lateral acceleration G is, the stronger the vehicle is affected by the crosswind and cant road surface, and the vehicle traveling on the adjacent lane ahead of the vehicle is also affected by the crosswind and cant road surface. The possibility of coming closer to the own lane is increased. Therefore, by generating the brake preload Ppre when the absolute value of the lateral acceleration G is large, a braking force is generated as soon as the driver operates the brake pedal when the adjacent vehicle comes in front of the host vehicle. The responsiveness to can be improved and the idling distance can be shortened.

  Further, as shown in FIG. 4, the brake preload Ppre is set to a larger value as the vehicle height H of the vehicle traveling on the adjacent lane ahead of the host vehicle is higher. When the brake preload Ppre reaches the maximum value Ppre_max, the maximum brake preload Ppre_max is constant even if the vehicle height H of the adjacent vehicle increases further.

  As shown in FIG. 6, the higher the vehicle height H of a vehicle such as a truck traveling in the adjacent lane in front of the host vehicle, the higher the possibility of approaching the host lane due to strong influence from crosswinds and cant road surfaces. Therefore, by generating a larger brake preload Ppre as the vehicle height H of the adjacent vehicle is higher, a braking force is generated immediately when the driver operates the brake pedal when the adjacent vehicle comes in front of the own vehicle. The responsiveness to can be improved and the idling distance can be shortened.

  Further, as shown in FIG. 5, the brake preload Ppre is set to a larger value as the host vehicle speed V is higher. At this time, as indicated by a solid line a in FIG. 5, a certain value is set for the brake preload Ppre when the host vehicle speed V is the lower limit vehicle speed (for example, 40 km / h) VL of the preceding vehicle following traveling control and constant speed traveling control. Alternatively, as indicated by a broken line b, the brake preload Ppre at the lower limit vehicle speed VL may be set to zero. When the brake preload Ppre reaches the maximum value Ppre_max, the maximum brake preload Ppre_max is constant even if the vehicle speed V increases further. Further, when the own vehicle speed V becomes lower than the lower limit vehicle speed VL of the preceding vehicle following traveling control and the constant speed traveling control, the rake preload Ppre is set to zero.

  The higher the host vehicle speed V, the faster the response to the brake operation and the shorter the mileage are required. Therefore, the higher the host vehicle speed V, the larger the brake preload Ppre is generated, and the adjacent vehicle has come in front of the host vehicle. Sometimes, when the driver operates the brake pedal, a braking force is generated, improving the responsiveness to the brake operation and shortening the idling distance.

  After determining the brake preload Ppre according to the absolute value of the lateral acceleration G, the vehicle height H of the adjacent vehicle, and the host vehicle speed V, the brake preload Ppre determined in step 6 is generated, and the process is terminated.

  Thus, according to the above-described embodiment, a vehicle traveling in an adjacent lane in front of the vehicle in which the lateral acceleration is generated in the lateral direction of the host vehicle and the direction opposite to the direction of the lateral acceleration is generated. When detected, the brake preload is generated, so the brake preload can be generated accurately according to the driving environment, improving the responsiveness to the brake operation and shortening the idling distance. it can.

  In the embodiment described above, a larger brake preload is generated as the absolute value of the lateral acceleration is larger. The larger the absolute value of the lateral acceleration, the stronger the influence of the crosswind and the cant road surface. Therefore, the possibility and the degree of approach of the adjacent vehicle to the own lane increase. Therefore, according to the embodiment, it is possible to generate an appropriate brake preload according to the approach degree of the adjacent vehicle.

  In the embodiment described above, the brake preload is increased as the vehicle height of the vehicle traveling in the adjacent lane increases. The higher the vehicle height of the adjacent vehicle, the stronger the influence of the crosswind and cant road surface, so the possibility and the degree of proximity of the adjacent vehicle approaching the own lane increase. Therefore, according to the embodiment, it is possible to generate an appropriate brake preload according to the approach degree of the adjacent vehicle.

  Furthermore, in the above-described embodiment, a greater brake preload is generated as the host vehicle speed is higher. The higher the host vehicle speed, the longer the free running distance at the time of the brake operation. Therefore, the degree of approach to the adjacent vehicle approaching or entering the host vehicle lane increases due to the influence of the crosswind or the cant road surface. Therefore, according to the embodiment, it is possible to generate an appropriate brake preload according to the approach degree of the adjacent vehicle.

  According to the embodiment described above, when the absolute value of the lateral acceleration G exceeds the threshold value GH, or when the vehicle height H of the vehicle traveling in the adjacent lane is higher than the threshold value Ho, the preceding vehicle Since the following braking control and constant speed traveling control are canceled and the maximum braking preload is generated after the traveling control is canceled, it is strongly affected by crosswinds and cant road surfaces. It is possible to generate an appropriate brake preload according to the driving environment.

According to the embodiment described above, after the brake preload is generated, the absolute value of the lateral acceleration G becomes equal to or less than the threshold value GL, or the vehicle traveling in the adjacent lane is not detected, Since the brake preload is released after a lapse of time, it is possible to prevent the brake preload from being generated unnecessarily for a long time.
In the present embodiment, a lateral acceleration sensor is provided to detect a crosswind or a cant road. The acceleration may be calculated.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the lateral acceleration sensor 8 is the lateral acceleration detecting means, the camera 9 and the image processing device 9a are the vehicle detecting means, the travel control controller 10 and the brake control device 13 are the brake preload generating means, and the vehicle speed sensor 2 is the own vehicle speed detecting means. The travel control controller 10 constitutes a control release unit. The above description is merely an example, and when interpreting the invention, the correspondence between the items described in the above embodiment and the items described in the claims is not limited or restricted.

It is a figure which shows the structure of one embodiment. It is a flowchart which shows the brake preload control program of one Embodiment. It is a figure explaining the determination method of the brake preload value according to a lateral acceleration. It is a figure explaining the determination method of the brake preload value according to the vehicle height of an adjacent vehicle. It is a figure explaining the determination method of the brake preload value according to the own vehicle speed. It is a figure which shows the state in which vehicles with high vehicle height, such as a truck, run along the adjacent lane ahead of the own vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inter-vehicle distance radar 2 Vehicle speed sensor 8 Lateral acceleration sensor 9 Camera 9a Image processing apparatus 10 Travel control controller 11 Engine control apparatus 12 Transmission control apparatus 13 Brake control apparatus

Claims (7)

In the travel control device that performs either one or both of the preceding vehicle follow-up travel control for setting the inter-vehicle distance to the preceding vehicle as the target inter-vehicle distance and the constant speed travel control for setting the own vehicle speed as the target vehicle speed,
Lateral acceleration detecting means for detecting lateral acceleration generated in the lateral direction of the host vehicle;
Vehicle detection means for detecting a vehicle traveling in an adjacent lane ahead of the host vehicle;
Brake preload is generated when the lateral acceleration occurs in the lateral direction of the host vehicle and a vehicle traveling in the adjacent lane is detected in front of the host vehicle in a direction opposite to the direction of the lateral acceleration. A travel control device comprising brake preload generation means. The travel control device according to claim 1,
The travel control device according to claim 1, wherein the brake preload generating means generates a greater brake preload as the absolute value of the lateral acceleration increases. In the traveling control device according to claim 1 or 2,
The vehicle detection means detects a vehicle height of a vehicle traveling in an adjacent lane ahead of the host vehicle,
The travel control device according to claim 1, wherein the brake preload generating means generates a greater brake preload as the vehicle height of a vehicle traveling in the adjacent lane is higher. In the travel control device according to any one of claims 1 to 3,
It has own vehicle speed detecting means for detecting the own vehicle speed,
The travel control device, wherein the brake preload generating means generates a greater brake preload as the host vehicle speed is higher. In the traveling control device according to claim 3 or 4,
When the absolute value of the lateral acceleration exceeds the first threshold value, or when the vehicle height of the vehicle traveling in the adjacent lane is higher than the threshold value, the preceding vehicle following traveling control and the constant speed traveling control are performed. Control release means for releasing,
The brake preload generating means generates a maximum brake preload after the preceding vehicle following traveling control and the constant speed traveling control are canceled by the control canceling means. In the travel control device according to any one of claims 1 to 5,
The brake preload generating means generates a brake preload, and then the absolute value of the lateral acceleration falls below a second threshold value lower than the first threshold value, or travels in the adjacent lane. A travel control device that releases brake preload after a predetermined time has elapsed since the vehicle is no longer detected.   A traveling control device that performs either one or both of a preceding vehicle following traveling control for setting the inter-vehicle distance to the preceding vehicle as a target inter-vehicle distance and a constant speed traveling control for setting the own vehicle speed as the target vehicle speed, When a lateral acceleration is generated in the lateral direction of the host vehicle and a vehicle traveling in the adjacent lane is detected in front of the host vehicle in a direction opposite to the direction in which the lateral acceleration is generated, a brake preload is generated in the host vehicle. A travel control device characterized by the above.

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