JPH11342766A - Inter-vehicle distance control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start a follow up control mode automatically, even when a vehicle is driven manually and stably while following to a preceding car. SOLUTION: In this device, by measuring the own car speed and the inter- vehicle distance between the own car and preceding car by using a radar device 1, it is judged whether or not the change amount of the inter-vehicle distance is in a prescribed stable range and also whether the change amount of the own car speed is in a prescribed stable range or not. Here, when the change amount of the inter-vehicle distance is in a prescribed stable range, a follow up control start judge part 24 judges that the follow up control mode following to the preceding car is started, when the change amount of the own car speed is in a prescribed stable range and the car speed control part 25 starts the control of the own car speed automatically so as to follow the preceding car, based on the car speed and the inter-vehicle distance before the start of this follow up control mode.

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 device capable of performing follow-up control while maintaining an inter-vehicle distance with a preceding vehicle at a predetermined distance corresponding to the own vehicle speed.

[0002]

2. Description of the Related Art Conventionally, an inter-vehicle distance control device has been designed so that the inter-vehicle distance from a preceding vehicle measured by a radar device or the like is kept constant in accordance with the current traveling vehicle speed. Adaptive cruise control system (hereinafter referred to as ACC), which controls the vehicle while controlling the vehicle, has been put to practical use. It can contribute to driving comfort, convenience, and reduction of driving load during long-distance driving on an expressway. It has the advantage of being able to.

In general, the following distance in the following control mode is
It is determined according to the current vehicle speed, and is set so that, for example, the inter-vehicle time is about 2 seconds. That is, for example, in the following control mode at a speed of 100 km / h, the inter-vehicle time is 27.7 m / s × 2 seconds = about 55 m. The ACC electronic control unit controls the throttle opening and, if necessary, the gear shift position so that the inter-vehicle distance with the preceding vehicle can be maintained at 55 m / h at a speed of 100 km / h. It works to secure the distance between vehicles.

[0004] In this case, the driver sets the main switch of the ACC system to the ON state in advance and travels on the highway. Then, when the vehicle reaches an arbitrary vehicle speed, the operation switch is turned ON, and if there is no preceding vehicle at this time, the vehicle shifts to the constant speed traveling control mode at the vehicle speed at the time of setting.
On the other hand, in this state, when approaching a preceding vehicle that is slower than the own vehicle, deceleration control is performed so that the inter-vehicle distance satisfies the inter-vehicle time, and tracking control at a vehicle speed lower than the set vehicle speed is performed. Done. As a result, smooth control was performed on a road with a small traffic volume.

[0005]

However, in the conventional inter-vehicle distance control apparatus, in an environment with heavy traffic and congestion, for example, even if the ACC electronic control unit is set at an arbitrary vehicle speed, immediately There is a problem in that the vehicle enters a sudden deceleration mode when approaching a slow car, resulting in a poor ride quality.

If the relative speed between the host vehicle and the preceding vehicle is high and the deceleration by the automatic deceleration control cannot be sufficient, a foot brake operation must be performed, and the operation of the ACC electronic control unit is released by the brake operation. Will be done. As a result, it is necessary to redo the speed setting by the switch operation again, which causes a problem that the driver feels troublesome.

[0007] The present invention has been made in view of the above,
It is an object of the present invention to provide an inter-vehicle distance control device that can automatically start a following control mode even when a vehicle is performing a stable manual operation following a preceding vehicle.

[0008]

According to the first aspect of the present invention,
In order to solve the above-mentioned problems, a vehicle speed measuring means for measuring a vehicle speed of the host vehicle and a vehicle distance measuring means for measuring a vehicle distance between the vehicle and a preceding vehicle are provided, and a variation amount of the vehicle distance is within a predetermined stable range. Vehicle speed state determining means for determining whether the vehicle speed variation is within a predetermined stable range; and vehicle speed state determining means for determining whether the vehicle speed variation is within a predetermined stable range. When the fluctuation amount of the own vehicle speed is within a predetermined stable range, the following control start determining means for determining to start the following control mode for following the preceding vehicle; and Vehicle speed control means for automatically starting the control of the own vehicle speed so as to follow the preceding vehicle based on the vehicle speed and the inter-vehicle distance is provided.

According to a second aspect of the present invention, there is provided a driving state detecting means for detecting at least a brake operation, a direction instruction operation, and a steering angle operation as a driving state of the vehicle, and the follow-up control start judging means. The gist of the invention is to judge that a tracking control mode for following a preceding vehicle is started when the driving state of the vehicle is stable.

According to a third aspect of the present invention, in order to solve the above-mentioned problem, the tracking control start determining means has a notifying means for notifying that the mode has automatically shifted to the tracking control mode.

According to a fourth aspect of the present invention, to solve the above-mentioned problem, an operation switch for automatically instructing a transition to a follow-up control mode is provided, and the follow-up control start judging means is configured to set the operation switch to an active state. , The point is that it is possible to automatically shift to the following control mode.

[0012]

According to the first aspect of the present invention, the own vehicle speed, the inter-vehicle distance between the own vehicle and the preceding vehicle are measured, and it is determined whether the amount of change in the inter-vehicle distance is within a predetermined stable range. At the same time, it is determined whether or not the fluctuation amount of the vehicle speed is within a predetermined stable range. Here, when the variation amount of the inter-vehicle distance is within a predetermined stable range, and when the variation amount of the own vehicle speed is within a predetermined stable range, it is determined that the following control mode for following the preceding vehicle is started, and Based on the vehicle speed and the inter-vehicle distance before the start of the control mode, by automatically starting the control of the own vehicle speed so as to follow the preceding vehicle, when the vehicle is manually driven following the preceding vehicle, The tracking control mode can be automatically started when the amount of change in the inter-vehicle distance and the amount of change in the vehicle speed are within predetermined stable ranges.

According to the second aspect of the present invention, in addition to the effect of the first aspect, at least a brake operation, a direction instruction operation, and a steering angle operation are detected as a driving state of the vehicle, and the operation of the vehicle is performed. By judging to start the following control mode for following the preceding vehicle when the state is stable, the following control mode can be automatically started even when the driving state of the vehicle is stable. .

According to the third aspect of the present invention, it is possible to prompt the driver to recognize that the vehicle is in the following control mode by automatically notifying that the vehicle has shifted to the following control mode.

According to the fourth aspect of the present invention, an operation switch is provided for instructing to automatically shift to the follow-up control mode, and when the operation switch is in an active state, the follow-up operation is automatically performed. Since the mode can be shifted to the control mode, the operation of the vehicle can be intentionally shifted to the following control mode.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a system configuration of an inter-vehicle distance control device according to one embodiment of the present invention.

As shown in FIG. 1, the following distance control device comprises:
A laser type or radio wave type radar device 1 for measuring the inter-vehicle distance, direction and relative speed between the preceding vehicle and the own vehicle, an ACC-ECU (electronic control unit) 2 for controlling the entire ACC system, and controlling a throttle opening. A throttle actuator 3 that adjusts the running speed of the vehicle, and a gear shift down for a greater deceleration when the deceleration effect is not sufficient just by closing the throttle when the relative speed between the preceding vehicle and the own vehicle is large. -ECU 4 for controlling the vehicle speed, a vehicle speed sensor 5 for detecting the traveling speed of the vehicle, and an ACC-EC
An indicator 6 that informs the driver of the running state of the own vehicle, the set vehicle speed, and the like as the operation state of U2, and a notice that the relative speed when approaching the preceding vehicle is large and prompts the driver to perform a deceleration operation by the foot brake. Alarm buzzer 7 and ACC-ECU
And a main switch 8 for turning on and off the main power supply of the power supply 2 when the foot brake operation is performed.
A brake switch 10 for canceling the operation of the C-ECU 2, a voice synthesis output device 11 for synthesizing a voice signal indicating, for example, automatically starting the follow-up control mode, and informing the driver, and immediately before the lane change. A turn signal switch 12 for detecting operation of a blinking turn signal, a steering angle sensor 13 for detecting a steering angle of a steering, and a release switch 14 for releasing and stopping the automatic constant speed traveling control mode and the following control mode. It is configured.

When using a laser beam, the radar apparatus 1 uses a scanning method in which the radar beam is swept within a range of about 12 degrees in the horizontal direction to obtain the angle information of the object to be measured. I have. In addition, when the radio wave method is used, the radar is generally 60 GHz to 77 GHz as an automobile radar.
A millimeter wave band of about z is used, and angle information to the object to be measured is obtained by a monopulse method or the like.

The display 6 is provided with a dedicated liquid crystal display on a meter panel for displaying characters, figures, and the like, a multi-display for displaying a navigation device, an operation display of an audio device, an operation display of an air conditioner, and the like. May also be used as a display.

Next, FIG. 2 shows the ACC-
FIG. 2 is a block diagram illustrating an internal configuration of an ECU 2. ACC-
The ECU 2 includes hardware such as a CPU, a ROM, a RAM, a timer, and the like, and each functional block is configured based on a control program stored in the ROM. When the distance measurement data of the object to be measured output from the radar device 1 is input to the preceding vehicle recognition processing unit 21, the preceding vehicle recognition processing unit 21 extracts the distance measurement data of the object to be measured on the own lane from the distance measurement data of the object to be measured. The distance data relating to the preceding vehicle is extracted and output to the headway state determination unit 22. The inter-vehicle state determination unit 22 determines whether or not distance data relating to a preceding vehicle on the own lane is within a predetermined range. The vehicle state determination unit 23 includes the vehicle speed sensor 5
Then, the current driving state of the own vehicle is determined by inputting various sensor signals of the own vehicle.

The follow-up control start judging section 24 judges from the inter-vehicle state judging section 22, the judgment result from the own vehicle state judging section 23, the brake operation from the brake switch 10, the instruction direction from the turn signal switch 12, and the steering angle. Based on the steering angle from the sensor 13 and the vehicle speed signal from the vehicle speed sensor 5,
It is determined whether or not to start the following control mode in which the vehicle runs following the preceding vehicle. The vehicle speed control unit 25 controls the AT shift position by the throttle actuator 3 and the AT-ECU 4 based on the determination result from the follow-up control start determination unit 24 to actually control the vehicle speed.

When it is necessary to urge the driver to perform the brake operation, the alarm determination unit 26 notifies the driver of the necessity of the deceleration operation by using an alarm display and an alarm buzzer sound. A situation in which the driver is urged to perform a brake operation is, for example, a case where the throttle is closed, such as when the preceding vehicle suddenly decelerates, and deceleration is insufficient only by downshifting.

Next, the operation of the following distance control apparatus will be described with reference to the flowchart shown in FIG. Here, when the ignition key is inserted into the key cylinder provided in the vehicle and the ON operation is performed to the accessory position, the power is supplied to the ACC-ECU 2 to start the activation.

First, in step S10, ACC-EC
U2 determines whether or not the main switch 8 has been turned ON. Step S when the main switch is OFF
The process of step 10 is repeated to enter the WAIT state.

On the other hand, when the main switch 8 is turned on, in step S20, the follow-up control mode is in a standby state, and distance measurement data such as distance data from the front object and angle data output from the radar device 1 are ACC.
-Input to ECU. In the case of radio radar,
The relative speed data is also directly measured and output. The ranging data from the radar device 1 is transmitted to the preceding vehicle recognition processing unit 2.
1 is input. In step S30, the traveling vehicle speed signal of the own vehicle from the vehicle speed sensor 5 is transmitted to the own vehicle state determination unit 23.
And the current traveling vehicle speed is measured.

In step S40, the preceding vehicle recognition processing unit 2
1 is based on the distance data and angle data to the forward distance measuring object and the vehicle state such as the own vehicle speed and the steering angle data, among the distance measuring objects detected ahead, and the most in front of the own vehicle lane. A vehicle traveling a short distance is recognized as a preceding vehicle to follow, and the vehicle is cascadedly tracked. Then, the distance data of the preceding vehicle being tracked is sent to the inter-vehicle state determination unit 22, and in step S50, it is determined whether or not a predetermined time (for example, about 6 seconds) has elapsed since the tracking of the preceding vehicle was started. I do. The process of step S50 is repeated until the fixed time elapses. Although the predetermined time used in step S50 is set to the past 5 seconds, the present invention is not limited to only such a case.

In step S60, the amount of change in the inter-vehicle distance from the preceding vehicle during the elapsed time is calculated. In step S70, the own vehicle state determination unit 23 calculates the amount of change in the own vehicle speed based on the vehicle speed signal input within the same elapsed time.

Next, in step S80, the following distance determination section 22 determines whether or not the calculated variation of the following distance is equal to or less than a predetermined value. If the inter-vehicle distance variation is larger than the predetermined value, the process returns to step S10. On the other hand, when the variation of the inter-vehicle distance is within the stable range smaller than the predetermined value, the process proceeds to step S90, and the own vehicle state determination unit 23 determines whether the calculated variation of the own vehicle speed is equal to or less than the predetermined value. Determine whether or not. If the vehicle speed fluctuation is larger than the predetermined value, the process returns to step S10.

In this embodiment, as a condition for automatically starting the follow-up control mode, it is determined whether or not the amount of change in the inter-vehicle distance and the amount of change in the vehicle speed are within the stable ranges. However, the present invention is not limited only to such a case, and a stable range is also determined in advance for the variation amount of the relative speed and the variation amount of the steering angle,
It may be used as a judgment condition.

When the vehicle speed fluctuation is within a stable range smaller than a predetermined value, the following distance is stable with respect to the preceding vehicle and the vehicle speed is also stable, so that the driver follows the current preceding vehicle. When it is determined that there is a driving intention, the following control start determining unit 24 starts preparing to enter the following mode for following the preceding vehicle. That is, in step S100, the vehicle speed upper limit value at the time of following is set to the average vehicle speed during the period in which the vehicle speed fluctuation was measured in the past. Next, in step S110, the target inter-vehicle distance at the time of following is set to the average inter-vehicle distance during the period in which the distance variation was measured in the past. In the present embodiment, the upper limit vehicle speed and the inter-vehicle distance that are automatically set are set to the average values within the past predetermined time, but the present invention is not limited to only such a case. Other setting methods such as setting between the maximum vehicle speed and the shortest vehicle within a predetermined time are also conceivable.

Here, the set inter-vehicle distance is set to an arbitrary distance of the driver, but it is necessary to secure a distance that does not cause abnormal approach or collision even when the preceding vehicle suddenly decelerates. is there. For this reason, a lower limit is set so that the set inter-vehicle distance cannot be shorter. In step S120, it is determined whether or not the previously set target inter-vehicle distance is equal to or greater than the lower limit. If the previously set target inter-vehicle distance is less than the lower limit, the process returns to step S10, and the process is repeated. The lower limit varies depending on the control characteristics of the vehicle and the like, but it is assumed that a generally used inter-vehicle time is, for example, about 1.8 seconds. That is, the minimum inter-vehicle distance at other speeds such as 100 km / h is about 60 m.

When the target inter-vehicle distance is equal to or larger than the lower limit value, the follow-up control start determining unit 24 sequentially determines the following based on the input brake switch signal, turn signal operation signal, and steering angle. Step S130
Then, it is determined whether or not the vehicle is in the OFF state in which the brake operation is not performed. Then, in step S140, it is determined whether or not the turn-off operation has not been performed in response to the lane change. Further, in step S150, it is determined whether the steering angle is stable. Alternatively, it is determined whether the vehicle is traveling on a sharp curve.

Here, if it is determined that the vehicle is in the stable state in all the determinations in steps S130 to S150, the process proceeds to step S160, and the driver is notified that adaptive cruise control is to be started. I do. That is, the automatic transition to the following control mode is notified from the speech synthesis output device 11 and the display 6. As a result, an example of display contents as shown in FIG. 4 is displayed on the display 6 on the meter panel. At this time, the indicator is turned on, and a letter indicating that the vehicle has automatically shifted to the following running state is displayed. Further, the inter-vehicle distance and the upper limit vehicle speed at that time are indicated by numerical values.

Next, in step S170, the vehicle speed control unit 25 connects the AT-E with the throttle actuator 3 of the vehicle.
By appropriately controlling the shift position via the CU 4, the following control mode in which the inter-vehicle distance with the preceding vehicle is kept constant according to the vehicle speed and the vehicle runs at a constant speed is executed. As a result, in the follow-up control mode, the throttle opening and the gear shift position are controlled as necessary, so that the distance between the vehicle and the preceding vehicle can be maintained constant while maintaining the vehicle speed. The follow-up control mode and the constant-speed traveling control mode are well-known technologies, and thus detailed description thereof will be omitted.

During the follow-up control, the preceding vehicle is constantly monitored by the radar device 1. In step S180, when the preceding vehicle changes lanes and departs from the own lane, the preceding vehicle accelerates and moves away from the own vehicle. When the vehicle is going, it is determined whether or not the preceding vehicle has left from the front of the vehicle, such as when the vehicle changes lanes. If the preceding vehicle has left from the front of the own vehicle, the process proceeds to step S190, and the vehicle speed control unit 25 shifts to the constant speed traveling control mode at the vehicle speed at which the preceding vehicle left.

On the other hand, if the preceding vehicle has not departed from the front of the own vehicle, the process proceeds to step S200. Since the preceding vehicle is cascaded, the own vehicle state determination unit 23 determines that the brake ON operation is performed during the following. It is determined whether or not it has been performed. If the brake is turned on during following, the process returns to step S10.
Repeat the process. On the other hand, if the brake has not been turned ON during following, it is determined whether or not the release switch 14 has been turned ON. If the release switch 14 has been turned ON, the process returns to step S10, and the process is repeated. On the other hand, if the release switch 14 has not been turned ON, the process returns to step S170, and the tracking control mode is cascaded.

Next, the flowchart shown in FIG. 3 will be described with reference to the traveling states shown in FIGS. FIG.
Shows an example of a change in the inter-vehicle distance for 5 seconds and a change in the own vehicle speed in units of 100 ms when following the preceding vehicle by manual accelerator operation. FIG. 6 shows the variation in numerical values. The average inter-vehicle distance for 5 seconds is 43.7 m, and the variation range of the distance is peak-to-peak.
0.9 m, the average of the own vehicle speed is 76.8 km / h, and the fluctuation range of the vehicle speed is 0.5 km / h from peak to peak.

First, as conditions for automatically starting the follow-up control mode, the stable range of the variation of the inter-vehicle distance used in step S80 is ± 1 m, and step S9 is performed.
The stable range of the fluctuation amount of the vehicle speed used at 0 is ± 1 km /
h, the lower limit of the set inter-vehicle distance used in step S120 is set to 1.8 seconds in inter-vehicle time.

In FIG. 6, the measured variation of the inter-vehicle distance of 0.9 m falls within the stable range of 1 m, and the variation of the vehicle speed of 0.5 km / h falls within the stable range of 1 km / h. . In this case, as the following condition, the upper limit of the vehicle speed is set to 76.8 km / h, which is the average of the vehicle speed, and the target inter-vehicle distance is 43.7, which is the average inter-vehicle distance during the measurement period.
m.

When the vehicle speed is 76.8 km / h, the inter-vehicle time of 1.8 seconds is 38.4 m in terms of distance, and the set target inter-vehicle distance of 43.7 m is larger than the lower limit of 38.4 m. Basically, the condition for shifting to the following control mode is satisfied. Thereafter, when the brake operation, the turn signal operation, and the large steering are not performed, steps S130 to S130 are performed.
150 is passed with "YES", and the following control mode is automatically started.

In step S170, after the vehicle speed control unit 25 shifts to the following control mode, the upper limit vehicle speed is 76.8 km.
/ H controls the throttle opening and the shift position so that the inter-vehicle distance at that time is 43.7 m. When the preceding vehicle decelerates, the target inter-vehicle distance is also adjusted so that the inter-vehicle time becomes 1.8 seconds. If the preceding vehicle has left from the front during the follow-up control at a vehicle speed of 76 km / h, the process proceeds to step S190, and shifts to the constant speed traveling control mode at the vehicle speed of 76 km / h.

As described above, the own vehicle speed and the inter-vehicle distance between the own vehicle and the preceding vehicle are measured using the radar device 1, and it is determined whether or not the amount of change in the inter-vehicle distance is within a predetermined stable range. It is determined whether or not the fluctuation amount of the vehicle speed is within a predetermined stable range. Here, the follow-up control start determining unit 24 performs a follow-up control mode for following the preceding vehicle when the amount of change in the following distance is within the predetermined stable range and when the amount of change in the vehicle speed is within the predetermined stable range. The vehicle speed control unit 25 automatically starts control of the own vehicle speed so as to follow the preceding vehicle based on the vehicle speed and the inter-vehicle distance before the start of the following control mode. Even when a stable manual operation is performed following the preceding vehicle, the following control mode is automatically started when the inter-vehicle distance fluctuation amount and the own vehicle speed fluctuation amount are respectively within the predetermined stable ranges. be able to.

As a result, even when the follow-up control mode is released due to the operation of the foot brake as in the prior art, it is not necessary to redo the speed setting by operating the switch again, and the driver feels troublesome. Without this, it is possible to return to the following control mode.

Further, when the vehicle is set to an arbitrary vehicle speed in a congested and heavy traffic environment as in the prior art, the vehicle immediately approaches a slower vehicle and does not enter the rapid deceleration mode. When the vehicle is manually operated following the vehicle, the vehicle can return to the following control mode, which can contribute to improving the riding comfort of the vehicle.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing an internal configuration of an ACC-ECU 2 of the following distance control device.

FIG. 3 is a flowchart for explaining the operation of the following distance control device.

FIG. 4 is a diagram showing an example of contents displayed on a display 6 on a meter panel.

FIG. 5 shows an example of a change in inter-vehicle distance for 5 seconds and a change in own vehicle speed in units of 100 ms while following a preceding vehicle by manual accelerator operation.

FIG. 6 is a table showing inter-vehicle distance variation and vehicle speed variation for 5 seconds while following a preceding vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radar apparatus 2 ACC-ECU 3 Throttle actuator 4 AT-ECU 5 Vehicle speed sensor 6 Display 7 Alarm buzzer 8 ACC main switch 10 Brake switch 11 Voice synthesis output device 12 Turn signal switch 13 Steering angle sensor 14 Release switch 21 Preceding vehicle recognition processing Unit 22 inter-vehicle state determination unit 23 own vehicle state determination unit 24 following control start determination unit 25 vehicle speed control unit 26 alarm determination unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // F16H 59:54 59:60

Claims (4)

[Claims] 1. A vehicle speed measuring means for measuring a vehicle speed of a vehicle, and an inter-vehicle distance measuring means for measuring an inter-vehicle distance between the own vehicle and a preceding vehicle, wherein a variation amount of the inter-vehicle distance is within a predetermined stable range. Inter-vehicle state determining means for determining whether or not the own vehicle speed fluctuation amount is within a predetermined stable range; and the own vehicle speed state determining means for determining whether the own vehicle speed fluctuation amount is within a predetermined stable range. In some cases, when the fluctuation amount of the own vehicle speed is within a predetermined stable range, a follow-up control start determining unit that determines to start a follow-up control mode that follows the preceding vehicle; and a vehicle speed before the start of the follow-up control mode; An inter-vehicle distance control device comprising: vehicle speed control means for automatically starting control of the own vehicle speed so as to follow a preceding vehicle based on the inter-vehicle distance. 2. The vehicle control system according to claim 1, further comprising: a driving state detecting unit configured to detect at least a brake operation, a direction instruction operation, and a steering angle operation as a driving state of the vehicle. 2. The inter-vehicle distance control device according to claim 1, wherein it is determined that a following control mode for following a preceding vehicle is started. 3. The inter-vehicle distance control apparatus according to claim 1, wherein the following control start determining means includes a notifying means for automatically notifying that the mode has shifted to the following control mode. 4. An operation switch for instructing to automatically shift to a follow-up control mode, wherein the follow-up control start determining means can automatically shift to a follow-up control mode when the operation switch is in an active state. The inter-vehicle distance control device according to claim 1, wherein