JP3276208B2 - Car travel control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control section for controlling a vehicle speed so as to travel at a constant speed at a predetermined target vehicle speed, and an inter-vehicle control for controlling the inter-vehicle distance between a host vehicle and a preceding vehicle to a predetermined target distance. A travel control device for an automobile having a distance control unit and
In particular, it relates to control when switching between vehicle speed control and inter-vehicle distance control.

[0002]

2. Description of the Related Art In recent years, in addition to a vehicle speed control function that keeps the vehicle speed constant, an inter-vehicle distance detection device such as an infrared laser radar device that detects the inter-vehicle distance between a host vehicle and a preceding vehicle has been used as a vehicle travel control device. A variety of devices equipped with a device and provided with an inter-vehicle distance control function for maintaining a safe inter-vehicle distance even when there is another vehicle as well as a single vehicle have been developed (see JP-A-1-114550). .

[0003] In such a traveling control device, when a slow preceding vehicle is detected during the vehicle speed control, the vehicle shifts to the inter-vehicle distance control. On the contrary, the preceding vehicle accelerates during the inter-vehicle distance control. When the vehicle speed of the preceding vehicle exceeds a target vehicle speed (set vehicle speed) set in advance by vehicle speed control, the vehicle does not follow the preceding vehicle any more, and shifts to constant speed running at the target vehicle speed, that is, vehicle speed control. I have.

[0004]

However, in the above-mentioned prior art, there is a problem in control when switching between vehicle speed control and inter-vehicle distance control. In other words, if the acceleration of the preceding vehicle is very slow, or if the preceding vehicle accelerates when viewed for a long time, but repeats acceleration and deceleration at the moment,
There is a possibility that the own vehicle wanders around the target vehicle speed of the vehicle speed control. In this case, the switching between the inter-vehicle distance control and the vehicle speed control is repeatedly performed, which causes acceleration / deceleration in the longitudinal direction of the vehicle body, resulting in poor ride comfort.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to provide a vehicle speed control and an inter-vehicle distance control when an own vehicle moves around a target vehicle speed of a vehicle speed control following a preceding vehicle. It is an object of the present invention to provide a traveling control device for an automobile that can prevent the occurrence of longitudinal acceleration / deceleration and thereby improve the riding comfort by preventing the switching of the control from being repeated between the two.

[0006]

In order to achieve the above object, the invention according to claim 1 comprises a vehicle speed control section for controlling a vehicle speed so as to run at a constant speed at a predetermined target vehicle speed, and a control device for controlling the speed of the own vehicle and the preceding vehicle. An inter-vehicle distance control unit that detects the inter-vehicle distance with the inter-vehicle distance detection device and controls the inter-vehicle distance to be a predetermined target inter-vehicle distance; and controls the vehicle speed of the preceding vehicle during the control by the inter-vehicle distance control unit by the vehicle speed control unit. When the vehicle speed becomes higher than the target vehicle speed, the control is switched to the control by the vehicle speed control unit. When the vehicle speed of the preceding vehicle becomes lower than the target vehicle speed during the control by the vehicle speed control unit, the control is switched to the control by the inter-vehicle distance control unit. After switching from the control by the inter-vehicle distance control unit to the control by the vehicle speed control unit by the switching unit and the switching unit , the acceleration of the preceding vehicle decreases after the switching.
Until a predetermined time set for a long time elapses, there is provided a regulating means for regulating switching to control by the inter-vehicle distance control unit even if the vehicle speed of the preceding vehicle becomes lower than the target vehicle speed.

[0007]

According to the above-mentioned structure, according to the first aspect of the present invention,
When the vehicle speed of the preceding vehicle fluctuates around the target vehicle speed control that is speed controlled by the speed control unit after the switching to the vehicle speed control from the control words inter-vehicle distance control by the headway distance control unit, the said switching, the preceding vehicle acceleration Is smaller
Until the predetermined time that is set to be long elapses, the switching to the inter-vehicle distance control is restricted by the restriction means even if the vehicle speed of the preceding vehicle becomes lower than the target vehicle speed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall configuration of a traveling control device for an automobile according to an embodiment of the present invention, and 1 is a throttle control device for automatically adjusting the opening of a throttle valve (not shown) of an engine intake system. Is a control device for an electronically controlled automatic transmission (EAT), and 3 is a brake control device for automatically adjusting the braking force applied to each wheel.
Each of the actuators 3 has an actuator (not shown), and each actuator is controlled by the control unit 4. That is, the control unit 4
Outputs a target throttle opening signal to an actuator of the throttle control device 1 to perform control, and outputs a target brake amount signal to an actuator of the brake control device 3 to perform control. The control unit 4 receives the shift position signal from a sensor (not shown) for detecting the shift position of the EAT
The shift control signal is output to the actuator of the AT control device 2 to perform control.

Reference numeral 6 denotes an information display device provided on an instrument panel or the like in the passenger compartment. The information display device 6 is turned on in response to an alarm signal from the control unit 4 (not shown). An alarm lamp and a display unit that receives a self-diagnosis signal from the control unit 4 and displays the screen on a screen are provided. Reference numeral 7 denotes an inter-vehicle distance detecting device for detecting an inter-vehicle distance between the host vehicle and the preceding vehicle. The inter-vehicle distance detecting device 7 comprises a laser radar device in the present embodiment, and emits laser light toward the front of the own vehicle. And receive the laser beam reflected from the vehicle ahead,
The inter-vehicle distance between the host vehicle and the preceding vehicle is detected based on the delay time between the reception time and the transmission time of the laser light, and the inter-vehicle distance signal as a detection signal is input to the control unit 4.

Further, 11 is a throttle opening sensor for detecting the opening of the throttle valve, 12 is a vehicle speed sensor for detecting the vehicle speed, 13 is a steering angle sensor for detecting the steering angle of the steering wheel, 1
Reference numeral 4 denotes a brake switch that is turned ON when the brake pedal is depressed, 15 denotes a yaw rate sensor that detects a yaw rate, 16 denotes a lateral G sensor that detects a lateral acceleration of the vehicle, 1
Reference numeral 7 denotes a clutch switch that is turned on in accordance with the operating state of the clutch.
Are input to the control unit 4. Note that detection signals from other sensors and switches, such as an engine speed sensor (not shown), are also input to the control unit 4.

As shown in FIG. 2, the control unit 4 starts detecting signals from the following distance detecting device 7,
An input information processing unit 21 that performs predetermined information processing in response to detection signals from various sensors and switches 11 to 17 and a normal control unit 22 that performs normal control by operating a driver
A vehicle speed control unit 23 that controls the vehicle speed so that the vehicle travels at a constant speed at a predetermined target vehicle speed; and an inter-vehicle distance control unit 24 that controls the vehicle speed so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes a predetermined target distance.
And a control switching unit 25 that issues a control command to any one of the three types of control units 22 to 24 based on the information obtained by the input information processing unit 21 to switch the control.
And an output information processing unit 26 that receives signals from the control units 22 to 24 and processes output information to be output to an operating unit (an actuator or the like) of the throttle control device 1 or the like.

The control switching by the control switching unit 25 will be described with reference to FIG. 3. When the inter-vehicle distance DIS between the host vehicle and the preceding vehicle is shorter than a predetermined inter-vehicle distance La, the inter-vehicle distance control is performed. The control by the unit 24, that is, the inter-vehicle distance control is performed. When the inter-vehicle distance DIS between the host vehicle and the preceding vehicle is longer than the predetermined inter-vehicle distance La, the control by the vehicle speed control unit 23, that is, the vehicle speed control is performed. When the vehicle speed of the preceding vehicle becomes equal to or higher than the target vehicle speed of the vehicle speed control during the following distance control, the control switching unit 25 switches to the vehicle speed control. In the inter-vehicle distance control region, in the A region where the relative speed REL between the host vehicle and the preceding vehicle is large in the positive direction (approaching direction) and the degree of danger is high, the alarm by the operation of the alarm display device 6 and the brake control device 3
The braking by the operation of the brake control device 3 is performed, and the braking by the operation of the brake control device 3 and the downshift by the operation of the EAT control device 2 are performed in the B region where the risk is medium. Only the throttle opening degree adjustment by the operation of the device 1 is performed.

Next, switching to the vehicle speed control by the control switching unit 25 when the vehicle speed of the preceding vehicle becomes equal to or higher than the target vehicle speed of the vehicle speed control during the following distance control will be described with reference to the flowchart shown in FIG.

In FIG. 4, first, at step S1.
In step S2, the vehicle speed VSP of the own vehicle (hereinafter referred to as own vehicle speed) detected by the vehicle speed sensor 12 and the inter-vehicle distance DIS between the own vehicle and the preceding vehicle detected by the inter-vehicle distance detection device 24 are read. Relative speed REL between the vehicle and the preceding vehicle
Is calculated. The relative speed REL is the amount of change in the inter-vehicle distance DIS between the host vehicle and the preceding vehicle per time, and is calculated by dividing the difference between the previous value and the previous value of the inter-vehicle distance DIS by a sampling period Δt (for example, 7 ms). You.

Subsequently, in step S3, the vehicle speed of the preceding vehicle (hereinafter referred to as the preceding vehicle speed) VSPF is calculated. The preceding vehicle speed VSPF is calculated by subtracting the relative speed REL from the own vehicle speed VSP. That is, the relational expression of VSPF = VSP-REL holds.

Subsequently, at step S4, the acceleration G of the preceding vehicle is calculated.
Calculate FV. This acceleration GFV is equal to the preceding vehicle speed VSP.
The difference between the previous value of F and the current value of F is calculated as the sampling period Δ
It is calculated by dividing by t. Thereafter, in step S5, a preset target vehicle speed VSPO of vehicle speed control is recognized, and in step S6, a target inter-vehicle distance DISO is calculated. The target inter-vehicle distance DISO is calculated using a map as shown in FIG. In this map, the target inter-vehicle distance D
ISO increases in a quadratic curve as the preceding vehicle speed VSPF increases.

Subsequently, at step S7, the preceding vehicle speed VSPF
Is higher than the target vehicle speed VSPO.

If the determination in step S7 is NO, it is determined in step S8 whether the flag F is 0. This flag F is for prohibiting switching from the vehicle speed control to the following distance control, and is set to 0 during the following distance control. If the determination in step S8 is YES, in step S9 the target inter-vehicle distance DIS
The control amount DACTP (= f (DISO-DIS)) of the inter-vehicle distance control according to the difference between O and the actual inter-vehicle distance DIS is calculated, and then, in step S16, the control amount DACT is calculated.
Required throttle opening TVP (= f (DAC
TP)) and returns.

On the other hand, if the determination in step S7 is YES, the flag F is set to 1 in step S10, and then the initial value of the tanmer Tt is set in step S11.
As shown in FIG. 6, the initial value of the tanmer Tt has a hyperbola functioning as a function of the acceleration GFV of the preceding vehicle, which is the amount of change in the preceding vehicle speed. The smaller the acceleration GFV of the preceding vehicle, the larger the value (positive integer). Is set to

Subsequently, at step S12, the target vehicle speed VSPO
And a control amount DACTP (= f (VSPO-VSP)) for vehicle speed control according to the difference between the vehicle speed VSP and the actual vehicle speed VSP. Thereafter, at step S13, the timer Tt is counted down by one, and at step S14, it is determined whether or not the timer Tt is zero. When this determination is NO, the process proceeds to step S16 to calculate the required throttle opening TVP corresponding to the control amount DACTP. On the other hand, when the determination is YES, the flag F is set to 0 in step S15.
In step S16, the required throttle opening TVP corresponding to the control amount DACTP is calculated.

In the above flowchart, step S
7, S8, S10-S16, the preceding vehicle speed V
After switching to the vehicle speed control when the SPF is higher than the target vehicle speed VSPO, a predetermined time (the sampling period and the initial value of the timer Tt (the acceleration GFV of the preceding vehicle is
Until the accumulated value of (the smaller value is set to a larger value ) elapses), the regulating means 3 for regulating the switching to the following distance control even if the vehicle speed of the preceding vehicle becomes lower than the target vehicle speed.
2 are configured.

According to the above flowchart, the control switching unit 25 switches to the vehicle speed control when the vehicle speed of the preceding vehicle becomes higher than the target vehicle speed during the following distance control, while the vehicle speed of the preceding vehicle changes during the vehicle speed control. When the vehicle speed becomes lower than the target vehicle speed, a switching means for switching to the following distance control is constituted.

Next, the operation and effect of the above embodiment will be described. The preceding vehicle accelerates during the following distance control and the preceding vehicle speed V
When the SPF fluctuates near the target vehicle speed VSPO of the vehicle speed control, the vehicle is switched to the vehicle speed control. However, the switching from the vehicle speed control to the inter-vehicle distance control is prohibited by the regulating means 32 for a predetermined time. As a result, the switching between the inter-vehicle distance control and the vehicle speed control is not frequently performed, and the occurrence of acceleration / deceleration in the vehicle body longitudinal direction due to the control switching can be prevented, and the riding comfort can be improved. it can.

Here, when the acceleration GFV, which is the amount of change in the preceding vehicle speed VSPF, is small, the acceleration GFV is larger than when the acceleration GFV is large.
The preceding vehicle speed VSPF often fluctuates near the target vehicle speed VSPO of the vehicle speed control for a long time. Therefore, in the case of the present embodiment, the predetermined time of the switching prohibition is set longer as the acceleration GFV, which is the change amount of the preceding vehicle speed VSPF, is smaller and corresponds to the fluctuation time. Can be appropriately performed, and it is possible to effectively achieve both the securing of safety and the improvement of riding comfort.

[0026]

As described above, according to the vehicle travel control device of the present invention, when the vehicle speed of the preceding vehicle fluctuates near the target vehicle speed of the vehicle speed control, the vehicle speed control is switched from the following distance control to the vehicle speed control. Until a predetermined time has elapsed since the switching, the switching to the inter-vehicle distance control is restricted even if the vehicle speed of the preceding vehicle is lower than the target vehicle speed, so that control is performed when the vehicle speed of the preceding vehicle fluctuates near the target vehicle speed. Frequent switching can prevent occurrence of front-rear acceleration / deceleration.
In addition, the predetermined time is longer as the acceleration of the preceding vehicle is lower.
The target vehicle speed control
It can correspond to the time fluctuating near the vehicle speed and control
Switching and prohibition of traffic properly to ensure safety and ride
It is possible to effectively achieve compatibility with improvement in comfort.

[Brief description of the drawings]

FIG. 1 is a block diagram of a travel control device for an automobile according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control unit.

FIG. 3 is a diagram for explaining a relationship between an inter-vehicle distance and the like and a control method.

FIG. 4 is a flow chart showing a control procedure for switching to vehicle speed control when the vehicle speed of a preceding vehicle becomes equal to or higher than a target vehicle speed of vehicle speed control during inter-vehicle distance control.

FIG. 5 is a diagram showing a map used for calculating a target following distance in the following distance control.

FIG. 6 is a diagram showing a map used for setting an initial value of a tanmer.

[Explanation of symbols]

 7 Inter-vehicle distance detection device 23 Vehicle speed control unit 25 Control switching unit (switching means) 24 Inter-vehicle distance control unit 32 Regulation means

Continuation of the front page (56) References JP-A-4-260836 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 31/00 F02D 29/02 301

Claims (1)

(57) [Claims] 1. A vehicle speed control unit for controlling a vehicle speed so as to travel at a predetermined target vehicle speed at a constant speed, an inter-vehicle distance between an own vehicle and a preceding vehicle detected by an inter-vehicle distance detection device, and the inter-vehicle distance is set to a predetermined target inter-vehicle distance. An inter-vehicle distance control unit that performs control such that when the vehicle speed of the preceding vehicle becomes higher than a target vehicle speed controlled by the vehicle speed control unit during control by the inter-vehicle distance control unit, control is switched to control by the vehicle speed control unit. Switching means for switching to control by the inter-vehicle distance control unit when the vehicle speed of the preceding vehicle becomes lower than the target vehicle speed during control by the vehicle speed control unit; After switching to the control, the vehicle speed of the preceding vehicle is lower than the target vehicle speed until a predetermined time that is set longer as the acceleration of the preceding vehicle decreases, after the switching. A travel control device for controlling the switching to the control by the inter-vehicle distance control unit even when the vehicle travels.