JP2003039973A - Inter-vehicle distance control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inter-vehicle distance control device which can continue action safely even when an inter-vehicle distance sensor detects performance deterioration due to stain on its cover. SOLUTION: This device has an inter-vehicle distance sensor 1 for measuring an inter-vehicle sensor from a preceding vehicle and a relative speed and an inter-vehicle distance control part 2 for driving following the preceding vehicle based on information measured by the inter-vehicle distance sensor 1. When a performance of the inter-vehicle distance sensor 1 to detect relation with the preceding vehicle is deteriorated, the inter-vehicle distance control part 2 moves the state of inter-vehicle distance control to a control method different from the control state when a detecting performance is not deteriorated. For example, when the performance of the inter-vehicle distance sensor 1 to detect the relation with the preceding vehicle is deteriorated, the inter-vehicle time from the preceding vehicle is set longer than the inter-vehicle time when the detecting performance is not deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an inter-vehicle distance sensor to measure an inter-vehicle distance between a host vehicle and a preceding vehicle,
The present invention relates to an inter-vehicle distance control device that automatically controls an inter-vehicle distance and travels following a preceding vehicle, and particularly relates to an operation of the inter-vehicle distance control device that is suitable when the inter-vehicle distance sensor is dirty.

[0002]

2. Description of the Related Art An inter-vehicle distance control device uses a laser radar or a millimeter wave radar to detect an inter-vehicle distance between a vehicle and a preceding vehicle,
It is known as a device that measures a relative speed and the like, automatically controls the inter-vehicle distance, and travels following a preceding vehicle, and assists the driver in driving. In the inter-vehicle distance control device, when the cover of the inter-vehicle distance sensor has dirt such as snow or mud, the detection performance of the inter-vehicle distance sensor is deteriorated due to attenuation of transmitted laser and radio waves. Therefore, for example, Japanese Patent Laid-Open No. 4-
As described in Japanese Patent No. 218435, it is known that in the conventional inter-vehicle distance control device, the inter-vehicle distance control is stopped when the detection performance deterioration of the inter-vehicle distance sensor is detected.

[0003]

However, according to the method disclosed in Japanese Patent Laid-Open No. 4-218435, the driver is difficult to drive, such as during snowfall or rain.
That is, when the driver most needs driving assistance,
There is a problem that the inter-vehicle distance control device cannot operate.

An object of the present invention is to provide an inter-vehicle distance control device capable of safely continuing its operation even when the inter-vehicle distance sensor detects a performance deterioration due to dirt on its cover.

[0005]

(1) In order to achieve the above object, the present invention provides an inter-vehicle distance sensor for measuring an inter-vehicle distance and a relative speed with a preceding vehicle, and information measured by the inter-vehicle distance sensor. Based on, in the inter-vehicle distance control device having an inter-vehicle distance control unit that travels following the preceding vehicle, the inter-vehicle distance control unit, when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor is reduced, The state of the inter-vehicle distance control is changed to a control method different from the control state when the detection performance is not deteriorated. With such a configuration, the operation can be safely continued even when the inter-vehicle distance sensor detects a performance deterioration due to dirt on the cover.

(2) In the above (1), preferably,
The inter-vehicle distance control unit is configured to restore the inter-vehicle distance control state to the control state when the detection performance is not deteriorated when the detection performance is reduced and the normal detection performance is restored. Is.

(3) In the above (1), preferably,
The inter-vehicle distance control unit makes the inter-vehicle time with the preceding vehicle longer than the inter-vehicle time when the detection performance is not deteriorated when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor is deteriorated. It is a thing.

(4) In the above (1), preferably,
The inter-vehicle distance control unit reduces the deceleration when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor decreases, compared to the deceleration when the detection performance does not decrease.

(5) In the above (1), preferably,
The inter-vehicle distance control unit makes the inter-vehicle time with the preceding vehicle longer than the inter-vehicle time when the detection performance is not deteriorated when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor is deteriorated. At the same time, the deceleration is made smaller than the deceleration when the detection performance is not deteriorated.

(6) In the above item (1), preferably,
The inter-vehicle distance control unit, when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor is reduced, the acceleration when performing follow-up control to the preceding vehicle, than the acceleration when the detection performance is not reduced. It is loose.

(7) In the above item (1), preferably,
The inter-vehicle distance control unit has a lane keeping function for maintaining the traveling lane of the vehicle, and when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor is reduced,
The lane keeping function is stopped.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The configuration and operation of an inter-vehicle distance control device according to a first embodiment of the present invention will be described below with reference to FIGS. First, the configuration of the inter-vehicle distance control device according to the present embodiment will be described with reference to FIG.
FIG. 1 is a system configuration diagram showing a configuration of an inter-vehicle distance control device according to a first embodiment of the present invention.

The inter-vehicle distance control apparatus according to the present embodiment comprises an inter-vehicle distance sensor unit 1, an inter-vehicle distance control unit 2 and an inter-vehicle distance sensor cover dirt removing unit 3, each of which is connected by a communication line 4. There is.

The inter-vehicle distance sensor section 1 is installed in the front section of the vehicle 5. The inter-vehicle distance sensor unit 1 emits a laser beam or a radio wave beam toward the front of the vehicle 5 and receives a reflected wave from the preceding vehicle 6. The inter-vehicle distance sensor unit 1 calculates the distance to the preceding vehicle 6, the relative speed, and the azimuth based on the received reflected wave, and the inter-vehicle distance control unit 2
To send those information to.

The inter-vehicle distance control section 2 includes an inter-vehicle distance sensor section 1
The distance to the preceding vehicle 6, the relative speed, and the azimuth information sent from the vehicle are received, and the distance and the relative speed for following the preceding vehicle 6 are calculated. The inter-vehicle distance control unit 2 transmits the information to the engine control unit 7 and the brake control unit 8 of the vehicle 5 so that the vehicle 5 can drive the preceding vehicle 6
It is controlled so that it automatically follows.

The inter-vehicle distance sensor unit 1 also calculates the degree of decrease in the detection performance due to dirt adhering to the cover based on the received reflected wave, and transmits the information on the degree of detection performance decrease to the inter-vehicle distance control unit 2. To do. The inter-vehicle distance control unit 2 changes the control content of the inter-vehicle distance control when the inter-vehicle distance sensor cover is dirty, based on the information on the degree of deterioration of the detection performance due to the dirt attached to the cover, which is received from the inter-vehicle distance sensor 1, The distance and the relative speed that the vehicle travels following the preceding vehicle 6 when the sensor cover is dirty are calculated. The inter-vehicle distance control unit 2 transmits the information to the engine control unit 7 and the brake control unit 8 of the vehicle 5 and controls the vehicle 5 to automatically follow the preceding vehicle 6. The control contents when the sensor cover is dirty will be described later with reference to FIG.

Further, the inter-vehicle distance control unit 2 determines whether or not the dirt needs to be removed based on the information on the degree of decrease in the detection performance due to the dirt adhering to the cover, which is received from the inter-vehicle distance sensor 1. If it needs to be removed, an operation signal is transmitted to the inter-vehicle distance sensor cover dirt removing section 3. The inter-vehicle distance sensor cover dirt removing unit 3 receives an operation signal from the inter-vehicle distance controller 2 and removes dirt adhering to the inter-vehicle distance sensor cover.

Next, the structure of the inter-vehicle distance sensor cover dirt removing section 3 used in the inter-vehicle distance control apparatus according to this embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a front view of the vehicle showing a configuration of an inter-vehicle distance sensor cover dirt removing section used in the inter-vehicle distance control device according to the first embodiment of the present invention, and FIG. 3 is a side view thereof.

The inter-vehicle distance sensor cover 9 shown in FIG. 2 is installed in front of the inter-vehicle distance sensor 1 shown in FIG.
The sensor cover 9 is installed for the purpose of protecting the inter-vehicle distance sensor 1 from snow, mud, stones, etc., and for improving the appearance of the vehicle 5. The inter-vehicle distance sensor cover dirt removing unit 3 is the same as the device for removing the dirt of the headlight.

As shown in FIG. 3, the inter-vehicle distance sensor cover dirt removing unit 3 sprays water or a dedicated cleaning liquid 10 to remove dirt adhering to the cover. Unlike this method, the vehicle-to-vehicle distance sensor cover dirt removing section 3 is like a windshield wiper for removing raindrops, and may be a dirt removing method.

Next, with reference to FIGS. 4 and 5, an inter-vehicle distance control method by the inter-vehicle distance control device according to the present embodiment will be described. FIG. 4 is a flowchart showing the content of the inter-vehicle distance control method by the inter-vehicle distance control device according to the first embodiment of the present invention, and FIG. 5 is the inter-vehicle distance control device by the inter-vehicle distance control device according to the first embodiment of the present invention. It is explanatory drawing of the content of the control method.

In step S1 of FIG. 4, the inter-vehicle distance control unit 2 determines whether or not the dirt needs to be removed based on the information on the degree of deterioration in the detection performance due to the dirt adhering to the cover received from the inter-vehicle distance sensor 1. To judge. If the detection performance of the inter-vehicle distance sensor 1 has not deteriorated, step S
If the detection performance is degraded, the procedure proceeds to step S3.

If the detection performance of the inter-vehicle distance sensor 1 has not deteriorated, in step S2, the inter-vehicle distance control unit 2 continues the automatic follow-up traveling by the normal inter-vehicle distance control. Here, with the normal inter-vehicle distance control, for example, the inter-vehicle time between the preceding vehicle 6 and the vehicle 5 (a value obtained by dividing the inter-vehicle distance between the preceding vehicle 6 and the vehicle 5 by the vehicle speed of the vehicle 5) is 2 seconds. It is in the state of following and traveling.

Here, a normal inter-vehicle distance control will be described with reference to FIG. In FIG. 5, the vertical axis represents the inter-vehicle time (s), and the horizontal axis represents the time t. The solid line A is
The transition of the inter-vehicle time during normal inter-vehicle distance control is shown.
The vehicle 5 is, for example, a constant speed (for example, 100 km /
It is assumed that the preceding vehicle 6 is approaching in h).

From time t0 to t1, the vehicle 5 is the preceding vehicle 6
The vehicle time is gradually shortening. During this time, the vehicle 5 is traveling at a constant speed.

Then, at time t1, the time between the preceding vehicle 6 and the preceding vehicle 6 is set in advance (in the illustrated example,
When the vehicle speed is 100 km / h for 2.5 seconds and the vehicle speed is 100 km / h, the inter-vehicle distance control unit 2 instructs the brake control unit 8 to decelerate and starts deceleration. The curvature of the change in the inter-vehicle time in the figure indicates the deceleration.

Further, at time t2, the inter-vehicle time is 2
At the second, the inter-vehicle distance control unit 2 instructs the engine control unit 7 to perform follow-up control so as to maintain the inter-vehicle time with the preceding vehicle for 2 seconds (about 50 m when the vehicle speed of the preceding vehicle is 90 km / h). To start.

On the other hand, when it is determined in step S1 in FIG. 4 that the detection performance of the inter-vehicle distance sensor 1 is degraded, the inter-vehicle distance control unit 2 determines in step S3 that the inter-vehicle distance sensor cover is dirty. Performs inter-vehicle distance control in hour mode. This is because, when the detection performance of the inter-vehicle distance sensor 1 is lowered, the performance of detecting the preceding vehicle 6 is deteriorated, and therefore the inter-vehicle distance needs to be made longer than in the normal state in order to ensure traveling safety. Because there is. When the sensor cover is dirty, for example, the inter-vehicle time between the preceding vehicle 6 and the host vehicle 5 is set to 3 seconds in order to provide a safety margin with respect to the normal inter-vehicle distance control of 2 seconds. It is in a state of traveling following.

Here, the inter-vehicle distance control when the sensor cover is dirty will be described with reference to FIG. A broken line B1 indicates a transition of the inter-vehicle time during inter-vehicle distance control when the sensor cover is dirty.

From time t0 to time t3, the vehicle distance control is the same as the normal inter-vehicle distance control, the vehicle 5 is gradually approaching the preceding vehicle 6, and the vehicle time is gradually shortened. During this time, the vehicle 5 is traveling at a constant speed.

Then, at time t3, the time between the preceding vehicle 6 and the preceding vehicle 6 is set in advance (in the example shown,
When the vehicle speed of the vehicle 5 is 100 km / h for 3.5 seconds, the inter-vehicle distance control unit 2 instructs the brake control unit 8 to decelerate when the distance to the preceding vehicle is about 97 m). The curvature of the change in the inter-vehicle time in the figure indicates the deceleration.

Further, at time t4, the inter-vehicle time is 3
At the time of second (when the vehicle speed of the preceding vehicle is 90 km / h, the distance to the preceding vehicle is approximately 75 m), the inter-vehicle distance control unit 2 instructs the engine control unit 7 to maintain the inter-vehicle time of 3 seconds. Follow-up control is started as follows.

There are also the following reasons for making the inter-vehicle distance longer than usual. That is, step S described later
In 4, the inter-vehicle distance sensor cover dirt removing section 3 is operated to remove the dirt, but at that time, the inter-vehicle distance sensor 1 cannot detect the preceding vehicle 6 for a short time.
This is because the electromagnetic waves transmitted and received by the inter-vehicle distance sensor 1 are attenuated by spraying a cleaning liquid such as water on the cover. Therefore, the inter-vehicle distance is controlled by making the inter-vehicle distance longer than in the normal state so that there is no risk of a rear-end collision even if the preceding vehicle 6 decelerates during this period and the inter-vehicle distance with the vehicle 5 becomes shorter.

Next, in step S4 of FIG. 4, the inter-vehicle distance control section 2 operates the inter-vehicle distance sensor dirt removing section 3 to remove the dirt adhering to the cover 9 of the inter-vehicle distance sensor.

Next, in step S5, the inter-vehicle distance control unit 2 determines whether or not the dirt adhering to the cover 9 has disappeared and the detection performance of the inter-vehicle distance sensor 1 has not deteriorated. When the detection performance is not reduced and the detection performance is recovered, the process returns to step S2 to return to the normal inter-vehicle distance control state.

On the other hand, if the detection performance is still reduced, it is determined that the cover has dirt that cannot be sufficiently removed by the operation of the inter-vehicle distance sensor cover dirt removing section 3.
The inter-vehicle distance control is turned off, and further the driver is informed that the cover 9 of the inter-vehicle distance sensor is dirty.

As described above, according to this embodiment, even if the detection performance of the inter-vehicle distance sensor is deteriorated because the cover of the inter-vehicle distance sensor is dirty, the safe inter-vehicle distance control can be maintained. In addition, during that time, dirt can be automatically removed, and safety and convenience can be ensured.

Next, the inter-vehicle distance control method by the inter-vehicle distance control device according to the second embodiment of the present invention will be described with reference to FIG. The configuration of the inter-vehicle distance control device according to this embodiment is the same as that shown in FIG. Also,
The content of the inter-vehicle distance control method by the inter-vehicle distance control device according to the present embodiment is the same as in the flowchart shown in FIG. FIG. 6 is an explanatory diagram showing the content of the inter-vehicle distance control method by the inter-vehicle distance control device according to the second embodiment of the present invention.
A solid line A in FIG. 6 indicates normal inter-vehicle distance control, as in the solid line A in FIG.

In this embodiment, the contents of the inter-vehicle distance control in the inter-vehicle distance sensor cover dirty mode in step S3 of FIG. 4 are different. When the detection performance of the inter-vehicle distance sensor 1 is reduced, the inter-vehicle distance control unit 2 determines that the sensor cover is dirty due to rainfall or snowfall, the friction coefficient of the road surface is reduced, and the deceleration is increased. Then, since there is a risk of slipping, etc., the deceleration is lowered from the normal state in order to ensure traveling safety. The control when the sensor cover is dirty is performed by, for example, reducing the deceleration when decelerating when the inter-vehicle time between the preceding vehicle 6 and the host vehicle 5 becomes shorter than a predetermined time, and then the inter-vehicle time of the normal inter-vehicle distance control is 2 seconds. Then, it is in a state of following the vehicle while maintaining the inter-vehicle time of 2 seconds.

Here, the inter-vehicle distance control when the sensor cover is dirty will be described with reference to FIG. A broken line B2 indicates the transition of the inter-vehicle time during inter-vehicle distance control when the sensor cover is dirty.

From time t0 to t5, the same as the normal inter-vehicle distance control (solid line A), the vehicle 5 is gradually approaching the preceding vehicle 6, and the vehicle time is gradually shortened. During this time, the vehicle 5 is traveling at a constant speed.

Then, at time t5, the time between the preceding vehicle 6 and the preceding vehicle 6 is set in advance (4 in the illustrated example).
When the vehicle speed of the vehicle 5 is 100 km / h per second, the distance to the preceding vehicle is about 110 m), and the inter-vehicle distance control unit 2 instructs the brake control unit 8 to decelerate and starts deceleration. At this time, the deceleration is indicated by the curvature θ2 of the inter-vehicle time in the figure, but if the deceleration during the normal inter-vehicle distance control is θ1, then the deceleration is higher than the normal deceleration θ1 as indicated by the broken line B2 in the figure. As the deceleration θ2 having a small deceleration, the speed is reduced.

Further, at time t6, the inter-vehicle time is 2
At a second (about 50 m when the vehicle speed of the preceding vehicle is 90 km / h), the following distance control unit 2 instructs the engine control unit 7 to perform follow-up control so that the following time between the preceding vehicle and the preceding vehicle is maintained for 2 seconds. To start.

Although the above description is for the case of deceleration, for example, when the preceding vehicle accelerates, the inter-vehicle time with the preceding vehicle becomes longer, and when the vehicle accelerates, the cover of the inter-vehicle distance sensor is When the detection performance of the inter-vehicle distance sensor is deteriorated due to dirt, the acceleration can be made slower than the acceleration in the normal inter-vehicle distance control.

As described above, according to this embodiment, safe inter-vehicle distance control can be maintained even if the detection performance of the inter-vehicle distance sensor deteriorates because the cover of the inter-vehicle distance sensor becomes dirty. In addition, during that time, dirt can be automatically removed, and safety and convenience can be ensured.

Next, the inter-vehicle distance control method by the inter-vehicle distance control device according to the third embodiment of the present invention will be described with reference to FIG. The configuration of the inter-vehicle distance control device according to this embodiment is the same as that shown in FIG. Also,
The content of the inter-vehicle distance control method by the inter-vehicle distance control device according to the present embodiment is the same as in the flowchart shown in FIG. FIG. 7 is an explanatory diagram of the content of the inter-vehicle distance control method by the inter-vehicle distance control device according to the third embodiment of the present invention.
Similar to the solid line A in FIG. 5, the solid line A in FIG. 7 indicates normal inter-vehicle distance control.

In this embodiment, the contents of the inter-vehicle distance control in the inter-vehicle distance sensor cover dirty mode in step S3 of FIG. 4 are different. When the detection performance of the inter-vehicle distance sensor 1 is reduced, the inter-vehicle distance control unit 2 determines that the sensor cover is dirty due to rainfall or snowfall, the friction coefficient of the road surface is reduced, and the deceleration is increased. Then, since there is a risk of slipping, etc., the deceleration is reduced from the normal state in order to ensure the safety of traveling. If the detection performance of the inter-vehicle distance sensor 1 is degraded, the preceding vehicle 6
Since the performance of detecting the vehicle deteriorates, the inter-vehicle distance is made longer than in the normal state in order to ensure the safety of traveling.
The control when the sensor cover is dirty is performed, for example, when the inter-vehicle time between the preceding vehicle 6 and the host vehicle 5 becomes shorter than a predetermined time, the deceleration at the time of deceleration is decreased, and then the inter-vehicle time of the inter-vehicle distance control becomes 3 seconds. The vehicle is in a state of following while maintaining the inter-vehicle time of 3 seconds.

Here, the inter-vehicle distance control when the sensor cover is dirty will be described with reference to FIG. A broken line B3 indicates the transition of the inter-vehicle time during inter-vehicle distance control when the sensor cover is dirty.

From time t0 to t7, the same as the normal inter-vehicle distance control (solid line A), the vehicle 5 is gradually approaching the preceding vehicle 6, and the vehicle time is gradually shortened. During this time, the vehicle 5 is traveling at a constant speed.

Then, at time t7, the time between the preceding vehicle 6 and the preceding vehicle 6 is set in advance (5 in the illustrated example).
When the vehicle speed of the vehicle 5 is 100 km / h per second, the distance to the preceding vehicle is about 138 m), and the following distance control unit 2 instructs the brake control unit 8 to decelerate and starts deceleration. At this time, the deceleration is indicated by the curvature θ of the headway time in the figure, but assuming that the deceleration during the normal inter-vehicle distance control is θ1, the normal deceleration θ1 is indicated by the broken line B3 in the figure.
The deceleration is set to a deceleration θ2 having a smaller deceleration than the deceleration.

Further, at time t8, the inter-vehicle time is 3
At the time of second (about 75 m when the vehicle speed of the preceding vehicle is 90 km / h), the following distance control unit 2 instructs the engine control unit 7 to perform follow-up control so as to maintain the following time between the preceding vehicle and 3 seconds. To start.

As described above, according to this embodiment, even if the detection performance of the inter-vehicle distance sensor is deteriorated because the cover of the inter-vehicle distance sensor is dirty, the safe inter-vehicle distance control can be maintained. In addition, during that time, dirt can be automatically removed, and safety and convenience can be ensured.

When the inter-vehicle distance control section has a lane keeping function of traveling while maintaining the lane of the vehicle, when the detection performance of the inter-vehicle distance sensor deteriorates due to the cover of the inter-vehicle distance sensor becoming dirty, It is also possible to cancel the lane keeping function.

[0054]

According to the present invention, the operation can be safely continued even when the inter-vehicle distance sensor detects the performance deterioration due to the dirt of the cover.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a configuration of an inter-vehicle distance control device according to a first embodiment of the present invention.

FIG. 2 is a front view of the vehicle showing a configuration of an inter-vehicle distance sensor cover dirt removing section used in the inter-vehicle distance control apparatus according to the first embodiment of the present invention.

FIG. 3 is a side view of FIG.

FIG. 4 is a flowchart showing the contents of a vehicle distance control method by the vehicle distance control device according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of contents of a vehicle distance control method by the vehicle distance control device according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the contents of an inter-vehicle distance control method by an inter-vehicle distance control device according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing the content of an inter-vehicle distance control method by an inter-vehicle distance control device according to a third embodiment of the present invention.

[Explanation of symbols]

1 ... Distance sensor 2 ... Distance control unit 3 ... Distance sensor cover dirt removal unit 4 ... communication line 5 ... Vehicle 6 ... Leading vehicle 7 ... Engine control unit 8 ... Brake control unit 9 ... Distance sensor cover 10 ... Cleaning liquid

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60R 21/00 627 B60R 21/00 627 F02D 29/02 301 F02D 29/02 301D G01S 13/93 G01S 13 / 93 Z // B60T 7/12 B60T 7/12 C F term (reference) 3D044 AA29 AB01 AC59 AD02 AD21 AE22 3D046 BB18 BB19 HH20 3G093 AA01 BA23 CB14 DB16 EA01 EB04 FA07 FB01 5J070 AB24 AC02 AC06 AC13 AE01 AF03 AF03

Claims (7)

[Claims] 1. An inter-vehicle distance having an inter-vehicle distance sensor for measuring an inter-vehicle distance and a relative speed with respect to a preceding vehicle, and an inter-vehicle distance control section for following the preceding vehicle on the basis of information measured by the inter-vehicle distance sensor. In the control device, the inter-vehicle distance control unit, when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor is reduced, the state of the inter-vehicle distance control, the control state when the detection performance is not reduced An inter-vehicle distance control device characterized by making a transition to a control method different from. 2. The inter-vehicle distance control device according to claim 1, wherein the inter-vehicle distance control unit eliminates the deterioration of the detection performance, and when the normal detection performance is restored, the inter-vehicle distance control state is detected. An inter-vehicle distance control device, which returns to a control state when the vehicle has not decreased. 3. The inter-vehicle distance control device according to claim 1, wherein the inter-vehicle distance control unit determines the inter-vehicle time with the preceding vehicle when the ability of the inter-vehicle distance sensor to detect the relationship with the preceding vehicle deteriorates. An inter-vehicle distance control device characterized in that the inter-vehicle distance is set longer than the inter-vehicle time when the detection performance is not deteriorated. 4. The inter-vehicle distance control device according to claim 1, wherein the inter-vehicle distance control section detects the deceleration when the performance of the inter-vehicle distance sensor for detecting the relationship with the preceding vehicle is lowered. An inter-vehicle distance control device characterized in that it is smaller than the deceleration when not decreasing. 5. The inter-vehicle distance control device according to claim 1, wherein the inter-vehicle distance control unit determines the inter-vehicle time with the preceding vehicle when the performance of detecting the relationship with the preceding vehicle by the inter-vehicle distance sensor deteriorates. The inter-vehicle distance control device is characterized in that the deceleration is set to be smaller than the deceleration when the detection performance is not deteriorated, while the deceleration is set to be longer than the inter-vehicle time when the detection performance is not deteriorated. 6. The inter-vehicle distance control device according to claim 1, wherein the inter-vehicle distance control unit follows the preceding vehicle when the performance of the inter-vehicle distance sensor for detecting the relationship with the preceding vehicle is deteriorated. The inter-vehicle distance control device is characterized in that the acceleration of the vehicle is made slower than the acceleration when the detection performance is not deteriorated. 7. The inter-vehicle distance control device according to claim 1, wherein the inter-vehicle distance control section has a lane keeping function for maintaining a traveling lane of the vehicle, and detects a relationship with a preceding vehicle by the inter-vehicle distance sensor. An inter-vehicle distance control device, characterized in that the lane keeping function is stopped when the performance deteriorates.