JP2000238629A - Inter-vehicle distance controlling constant speed traveling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a remarkable rise in a brake temperature by switching inter-vehicle distance control so as to reduce a deceleration frequency by brake driving when judging the deterioration of brake performance. SOLUTION: When a traveling speed of a preceding vehicle follows at a speed lower than a preset vehicle speed, and when a brake temperature detected by a brake temperature sensor 6 becomes a control switching temperature or more predetermined by a system in an inter-vehicle distance control part 102, preset inter-vehicle time is increased, and an inter-vehicle distance follow-up responsiveness control parameter is changed so that responsiveness of inter- vehicle follow-up performance becomes dull to arithmetically operate a vehicle speed command value. A throttle actuator 13 is closed according to the vehicle speed command value in a vehicle speed control part 103, and deceleration by shift-down is peformed by an AT controller 14. When sufficient deceleration cannot be performed, deceleration control by driving of a brake actuator 12 is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance control type constant-speed traveling apparatus, and more particularly, to an inter-vehicle distance control type constant speed traveling apparatus which performs control to follow a preceding vehicle so as to maintain a preset inter-vehicle distance. .

[0002]

2. Description of the Related Art Conventional inter-vehicle distance control type constant speed traveling apparatuses are disclosed in, for example, Japanese Patent Application Laid-Open No. 7-65297 and
As disclosed in Japanese Unexamined Patent Publication No. 961/961, a preceding vehicle is recognized by an inter-vehicle distance measuring means such as a laser radar, and the inter-vehicle time with the preceding vehicle (= inter-vehicle distance / running speed) is set to a preset time. A device that controls the traveling speed of a host vehicle is known. In these devices, when the vehicle is controlled to follow the preceding vehicle within the traveling speed command value of the own vehicle,
When the inter-vehicle time between the host vehicle and the preceding vehicle becomes smaller than the preset inter-vehicle time and the inter-vehicle distance decreases, the running speed of the own vehicle is controlled so as to maintain the inter-vehicle time by controlling the throttle actuator, shift range and brake actuator of the engine. Control.

[0003]

However, in such a conventional inter-vehicle distance control type constant-speed traveling apparatus, when the preceding vehicle follows the preceding vehicle within the traveling speed command value of the own vehicle, the preceding vehicle frequently occurs. When the acceleration and deceleration are repeated, the own vehicle drives the downshift and the throttle actuator and the brake actuator to maintain the inter-vehicle distance when the preceding vehicle decelerates. Here, when the brake actuator is automatically and repeatedly driven at a high frequency, there is a problem that the braking performance may be unexpectedly deteriorated by the driver due to a significant increase in the brake temperature.

The present invention has been made in view of such a conventional problem. In accordance with an increase in the brake temperature, the inter-vehicle time is set to be larger than when the brake temperature is low. Significant increase in brake temperature by slowing the responsiveness of the acceleration / deceleration characteristics of the host vehicle (hereinafter referred to as inter-vehicle distance tracking performance) and maintaining the set inter-vehicle time with the preceding vehicle, and by reducing the drive frequency of the brake actuator It is an object of the present invention to solve the above problem by adopting a method of preventing the above.

[0005]

The present invention has the following structure to solve the above-mentioned problems (see FIG. 4).
According to a first aspect of the present invention, an inter-vehicle distance detecting means A for detecting an inter-vehicle distance to a preceding vehicle, and an inter-vehicle time (= inter-vehicle distance / running) when the own vehicle travels following the preceding vehicle Speed), an inter-vehicle distance control means C for calculating a target vehicle speed command value so as to maintain the inter-vehicle time set by the inter-vehicle distance setting means A, and deceleration of the host vehicle. Sometimes, in a headway distance control type constant speed traveling apparatus having at least a vehicle speed control means F for decelerating by a brake drive, a brake performance measuring means D for measuring a state of brake performance and a brake performance measuring means D If the deterioration is determined, the control method switching means E for switching the control method of the control means C so that the frequency of deceleration by the brake drive is reduced. It is characterized in that it comprises.

According to a second aspect of the present invention, there is provided the inter-vehicle distance control type constant-speed traveling apparatus according to the first invention, wherein the inter-vehicle distance control method switching means E includes a brake performance measuring means D.
If it is determined that the braking performance has deteriorated, the inter-vehicle time set by the inter-vehicle distance setting means A is changed to be large, and the convergence of the relative speed change between the preceding vehicle and the host vehicle is moderated. The frequency of deceleration by the brake drive is reduced by changing to (1).

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a constant speed traveling apparatus according to the present invention. FIG. 1 is a block diagram showing a configuration of an embodiment of a constant-speed traveling apparatus of the following distance control type according to the present invention.

First, the configuration will be described. In FIG. 1, a laser radar 1 transmits a laser beam, receives reflected light from an object, and measures a time from transmission to reception of the light to detect an inter-vehicle distance to a preceding object such as a preceding vehicle. The CCD camera 2 captures an image of a road scene ahead of the host vehicle and outputs image data. The vehicle speed sensor 3 detects the running speed Vf (own vehicle speed) of the own vehicle, the throttle sensor 4 detects the opening of the throttle valve, the operation switch 5 starts and cancels the system, and the running speed command value of the own vehicle (setting). It is an operation member for setting the vehicle speed), setting the inter-vehicle time between the preceding vehicle and the own vehicle, and the like. Further, the brake temperature sensor 6 detects the brake temperature of the host vehicle.

The constant-speed traveling controller 100 recognizes a preceding vehicle on its own lane based on the inter-vehicle distance measured by the laser radar 1 and image data captured by the CCD camera 2, and determines the inter-vehicle distance from the preceding vehicle. L, a preceding vehicle recognizing unit 101 that calculates a relative speed Vr with respect to the preceding vehicle from a temporal change in the following distance L, and a set inter-vehicle time tL when the operation switch 5 activates the system.
1 and the set vehicle speed V1, and a vehicle speed command value V _ACC for following the preceding vehicle while maintaining an optimum inter-vehicle distance based on the inter-vehicle distance L and the relative speed Vr from the preceding vehicle output from the preceding vehicle recognition unit 101. Is calculated, and the inter-vehicle distance control unit 102 that controls the display device 11 that displays the setting state of the system
And a vehicle speed control unit 103 that calculates braking / driving torque for controlling a shift range by the brake actuator 12, the throttle actuator 13, and the AT controller 14 according to the vehicle speed command value _VACC .

[0010] Here, as shown in FIG.
When the traveling temperature of the preceding vehicle is following at a speed lower than the set vehicle speed V1, and the brake temperature T detected by the brake temperature sensor 6 becomes equal to or higher than the control switching temperature T0 determined in advance by the system. , An inter-vehicle time tL1 set from the operation switch 5 to an offset time tL2.
(TL2> 0) to increase the set inter-vehicle time, change the inter-vehicle distance following response control parameter from G1 to G2 so that the inter-vehicle distance following performance response characteristic becomes dull, and calculate the vehicle speed command value V _ACC . Execute.

When the traveling speed of the preceding vehicle is higher than the set vehicle speed V1 of the own vehicle, the vehicle speed control unit 103 controls the throttle actuator 1 so that the own vehicle speed becomes equal to the set vehicle speed.
3 is controlled, and conversely, when the traveling speed of the preceding vehicle is lower than the set vehicle speed V1, the throttle actuator 13 is closed in accordance with the vehicle speed command value _VACC , and the AT controller 14 performs deceleration by downshifting. When sufficient deceleration cannot be performed, deceleration control by driving the brake actuator 12 is added.

Next, the operation of the present embodiment will be described. FIG. 3 is a control flowchart of the present embodiment. In FIGS. 1 and 3, the cruise controller 100 determines whether the system is set to be activated by the operation switch 5 (step S1). If the system is activated, the presence / absence of a following vehicle to follow is determined (step S1). Step S2) and comparison between the traveling speed of the preceding vehicle and the set speed of the own vehicle (Step S2)
Perform 3). If there is no preceding vehicle, or if the set vehicle speed V1 of the own vehicle is lower than the running speed of the preceding vehicle, the throttle actuator 13 is controlled so as to run at a constant speed at the set vehicle speed V1 (step S4).

Next, when there is a preceding vehicle and the set speed V1 of the own vehicle is higher than the traveling speed of the preceding vehicle, the following distance control is executed. That is, when the preceding vehicle is traveling at a lower speed than the own vehicle, the acceleration / deceleration control by the throttle actuator 13 and the AT controller 14 is performed so as to maintain the inter-vehicle distance L. If the deceleration control by the above control is insufficient, the brake actuator 12 is driven to follow the preceding vehicle at the same speed as the preceding vehicle. At this time, the inter-vehicle distance L is calculated by the following equation based on the inter-vehicle time tL1 set in advance and the preceding vehicle speed V (= own vehicle speed Vf). L [m] = tL1 [s] · V [m / s] = tL1 [s]
Vf [m / s] Here, the preceding vehicle speed V is calculated based on the speed Vf of the own vehicle and the relative speed Vr. When the vehicle follows the preceding vehicle at the same speed as the preceding vehicle, The relative speed Vr is 0, and the preceding vehicle speed V is equal to the host vehicle speed Vf.

Next, the brake temperature T is changed to the control switching temperature T.
It is determined whether it is 0 or more (step S5). If the brake temperature T <T0, the inter-vehicle time tL1 set by the operation switch 5 and the inter-vehicle distance following response control parameter G1
To calculate the vehicle speed command value _VACC (step S6).
On the other hand, if the brake temperature T ≧ T0 due to frequent driving of the brake actuator 12 to follow the preceding vehicle, the set inter-vehicle time (tL1 + tL) obtained by adding the offset time tL2 to the inter-vehicle time tL1.
A vehicle speed command value _VACC is calculated based on 2) and the following distance control parameter G2 (step S7). here,
The control switching temperature T0 is a temperature at which significant deterioration of the brake is predicted when the brake temperature becomes equal to or higher than T0. Further, the inter-vehicle distance following response control parameter is changed from G1 to G2.
The response characteristic of inter-vehicle distance following performance becomes dull, and the manner of convergence of the speed change of the relative speed Vr between the preceding vehicle and the own vehicle becomes gentle.

Further, the braking / driving torque output to the throttle actuator 13, the AT controller 14, and the brake actuator 12 is calculated in accordance with the vehicle speed command value V _ACC (step S8), so that the following distance L from the preceding vehicle is calculated.
Is maintained, and the traveling speed of the own vehicle is controlled so that the relative speed Vr becomes zero. However, relative speed V with the preceding vehicle
r becomes extremely large and approaches rapidly (step S
9, Yes), the deceleration operation by the occupant is displayed on the display device 11.
And the system operation is canceled (step S10).

[0016]

As described above in detail, according to the present invention, the structure is set such that the inter-vehicle time is increased as the brake temperature increases, as compared with when the brake temperature is low. Because the responsiveness of the following distance following performance with the preceding vehicle is made slower, the convergence of the relative speed change between the preceding vehicle and the own vehicle is made slower, and the frequency of deceleration by the drive of the brake actuator is reduced. This prevents the driver from unexpectedly deteriorating the braking performance due to the increase in the vehicle speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a constant-speed traveling apparatus according to the present invention;

FIG. 2 is a diagram showing an inter-vehicle distance control parameter change table in one embodiment of the inter-vehicle distance control type constant-speed traveling device according to the present invention.

FIG. 3 is a control flowchart in one embodiment of the inter-vehicle distance control type constant-speed traveling device according to the present invention.

FIG. 4 is a diagram corresponding to claims of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser radar 2 CCD camera 3 vehicle speed sensor 4 throttle sensor 5 operation switch 6 brake temperature sensor 11 display device 12 brake actuator 13 throttle actuator 14 AT controller 100 constant speed traveling controller 101 preceding vehicle recognition unit 102 inter-vehicle distance control unit 103 vehicle speed control unit A inter-vehicle distance detecting means B inter-vehicle distance setting means C inter-vehicle distance control means D braking performance measuring means E inter-vehicle distance control method switching means F vehicle speed control means

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) G08G 1/16 B60R 21/00 624D 627 F Term (Reference) 3D041 AA41 AA65 AA71 AB01 AC01 AC26 AD04 AD41 AD46 AD50 AD51 AE04 AE41 AE45 AF02 LL04 LL09

Claims (2)

[Claims] An inter-vehicle distance detecting means for detecting an inter-vehicle distance from a preceding vehicle, and an inter-vehicle distance setting for setting an inter-vehicle time (= inter-vehicle distance / running speed) when the own vehicle travels following the preceding vehicle. Means, an inter-vehicle distance control means for calculating a target vehicle speed command value so as to maintain the inter-vehicle time set by the inter-vehicle distance setting means, and a vehicle speed for at least deceleration by brake driving when the own vehicle is decelerated. An inter-vehicle distance control type constant-speed traveling apparatus comprising: a braking performance measuring means for measuring a state of braking performance; and the inter-vehicle distance, when the braking performance is determined to be degraded by the braking performance measuring means. Inter-vehicle distance control method switching means for switching the control method by the control means so as to reduce the frequency of deceleration by the brake drive. Distance control type constant speed running device. 2. The inter-vehicle distance control type constant-speed traveling apparatus according to claim 1, wherein the inter-vehicle distance control method switching unit is configured to determine the inter-vehicle distance when the brake performance measuring unit determines that the brake performance has deteriorated. Along with changing the inter-vehicle time set by the setting means to be large, and by changing the convergence of the relative speed change between the preceding vehicle and the own vehicle so as to be gentle, the deceleration frequency by the brake drive is reduced. Characteristic is the inter-vehicle distance control type constant speed traveling device.