JP3788597B2 - Follow-up traveling device and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention detects a distance between a host vehicle and a preceding vehicle that travels in the same lane, and keeps the distance between the vehicles at a target distance according to the host vehicle speed while following the preceding vehicle and a control method therefor About.
[0002]
[Prior art]
Conventionally, a follow-up traveling device such as an inter-vehicle distance control type constant speed traveling device mounted as an assist for safe driving of an automobile has conventionally been, for example, 60 m when the own vehicle speed is 60 km / h, and 100 m when the own vehicle speed is 100 km / h. The target vehicle distance is determined according to the vehicle speed of the vehicle, and the vehicle ahead of the vehicle travels in the same lane as the vehicle based on the detection result of the vehicle distance from the vehicle traveling in front of the vehicle by the vehicle distance detection means comprising the vehicle distance sensor. If it is determined whether the vehicle is a preceding vehicle, and it is determined that the vehicle is a preceding vehicle, control is performed to maintain the inter-vehicle distance with the preceding vehicle at the target inter-vehicle distance. Some control is based on the inter-vehicle time instead of the inter-vehicle distance.
[0003]
In particular, the required acceleration / deceleration is derived from the inter-vehicle distance by the inter-vehicle distance sensor and the relative speed between the host vehicle and the preceding vehicle, and when the required acceleration / deceleration satisfies a certain condition, the throttle valve is opened to accelerate, or The vehicle is decelerated by operating a so-called automatic brake, such as closing the throttle valve or forcibly operating the brake.
[0004]
At this time, with respect to acceleration, even if the response is slightly delayed, there is little problem, but in the case of deceleration, it is not preferable that the response is delayed, so deceleration control is performed by the following two methods, for example. One of them is a method of operating an automatic brake when the required deceleration derived as described above falls below a preset threshold Artth, as shown in FIG. 3, and the other is a method of FIG. As shown in FIG. 4, when the deviation ΔA between the required deceleration and the actual deceleration derived from the time change of the host vehicle speed becomes larger than a predetermined deviation threshold value ΔAth, the automatic brake is activated. It is a technique. In addition, since the acceleration / deceleration on the vertical axis in FIGS. 3 and 4 is positive in the traveling direction of the vehicle, the required deceleration occurs on the negative side.
[0005]
[Problems to be solved by the invention]
However, in these conventional methods, since the threshold value Artth or the deviation threshold value ΔAth is fixed, the required deceleration is slightly below the threshold value Artth, or the deviation ΔA between the required deceleration and the actual deceleration is small. If the deviation threshold value ΔAth is exceeded even a little, the automatic brake is activated, resulting in a problem that the automatic brake is frequently activated and the driver feels bothersome. In addition, there is a possibility that the deterioration of the parts may be caused by the increase in the operation frequency of the automatic brake.
[0006]
Specifically, for example, when driving on an expressway, if the preceding vehicle loosens the accelerator, the inter-vehicle distance is shortened and the required deceleration Ar falls below the threshold value Artth, but the automatic brake is not activated immediately. However, the actual inter-vehicle distance is slightly shorter than the target inter-vehicle distance at that time, and the automatic brake is activated although it is not always necessary to activate the automatic brake.
[0007]
On the other hand, in order to eliminate such an inconvenience, it is conceivable that the threshold value Arth or the deviation threshold value ΔAth is set to a large value to make it difficult to operate the automatic brake. A delay will occur, giving the driver a sense of incongruity.
[0008]
Further, in order to make it difficult for the automatic brake to operate similarly, it is possible to reduce the required deceleration itself as shown by the broken line in FIG. However, since the actual deceleration derived similarly becomes small, it is not a good idea.
[0009]
Therefore, an object of the present invention is to prevent frequent operation of an automatic brake and to prevent a delay in operation of the automatic brake.
[0012]
[Means for Solving the Problems]
In order to achieve the above-described object , the follow-up traveling device according to the invention described in claim 1 detects the inter-vehicle distance between the host vehicle and a preceding vehicle traveling in the same lane, and performs acceleration / deceleration control on the acceleration / deceleration means. An inter-vehicle distance detecting means for detecting an inter-vehicle distance between the own vehicle and the preceding vehicle at a predetermined repetition time in a follow-up traveling device that follows the preceding vehicle while maintaining the inter-vehicle distance at a target inter-vehicle distance corresponding to the own vehicle speed. When the vehicle speed detecting means for detecting a vehicle speed, wherein the detecting following distance is detected for each by Ri the repetition time to said vehicle distance detecting means according to said vehicle speed detecting means and a vehicle speed of the preceding vehicle and the subject vehicle derives the relative speed, as well as derive the required deceleration from the the detecting inter-vehicle distance and the relative velocity detected for each of the repetition time, derivation hand to derive the relative acceleration of the preceding vehicle from the relative speed and the derived When, together with the request deceleration to the deceleration control of the deceleration means when the request deceleration is determined whether or not lower than a predetermined threshold value is below the threshold by the deriving means, wherein From the detected inter-vehicle distance and the relative speed detected at each repetition time , the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time longer than the repetition time is determined as the detected inter-vehicle distance and the relative speed × the predetermined time. predicting a predicted value by subtraction operation between the error between the predicted values and the measured value at a predetermined time has elapsed, it is determined whether or not the squid smaller than a predetermined value, the error is smaller than the predetermined value And control means for changing the threshold value small on condition that the relative acceleration is positive when the predetermined time has elapsed .
[0013]
According to such a configuration, when the error between the predicted value of the inter-vehicle distance between the own vehicle and the preceding vehicle after a predetermined time and the actual measurement value is smaller than the predetermined value and the relative acceleration is positive, the automatic brake is activated. In such a situation, the threshold value is changed to a smaller value by the control means, so the number of cases where the required deceleration is less than the threshold value is reduced, and the automatic brake operates frequently. Can be prevented.
[0014]
On the other hand, when the error between the predicted value of the inter-vehicle distance between the host vehicle and the preceding vehicle after the predetermined time and the measured value is larger than the predetermined value, or when the relative acceleration is negative, it is not necessary to operate the automatic brake. Since it cannot be determined that there is, the threshold value is not changed by the control means, and the automatic brake can be operated without delay.
[0017]
According to a second aspect of the present invention, there is provided a control method for a follow-up traveling device that detects an inter-vehicle distance between a host vehicle and a preceding vehicle traveling in the same lane, and controls acceleration / deceleration means to control the inter-vehicle distance. In the control method of the following traveling device that follows the preceding vehicle while maintaining the target inter-vehicle distance according to the own vehicle speed, the inter-vehicle distance between the own vehicle and the preceding vehicle is detected at predetermined repetition times to detect the own vehicle speed. And deriving a relative speed between the own vehicle and the preceding vehicle from the detected inter-vehicle distance detected at each repetition time and the own vehicle speed, and detecting the detected inter-vehicle distance and the relative speed detected at each repetition time. with deriving the request deceleration from derives the relative acceleration of the preceding vehicle from the relative speed and the derived, the request down request deceleration and the derived it is determined whether or not lower than a predetermined threshold value Speed is the threshold With the acceleration and deceleration means for controlling deceleration when below, the repetition from the detection headway distance and the relative velocity is detected for each time, the repetition vehicle a long predetermined time after the time of the preceding vehicle The inter-vehicle distance is predicted as a predicted value obtained by adding or subtracting the detected inter-vehicle distance and the relative speed × the predetermined time, and an error between the predicted value and the actually measured value when the predetermined time elapses is smaller than a predetermined value. squid determines whether the error is rather smaller than the predetermined value, and the relative acceleration at the time elapses the predetermined time on condition that a positive, is characterized by changing reduce the threshold .
[0018]
According to such a configuration, when the error between the predicted value of the inter-vehicle distance between the own vehicle and the preceding vehicle after a predetermined time and the actual measurement value is smaller than the predetermined value and the relative acceleration is positive, the automatic brake is activated. It is possible to determine that there is no need to operate, and in such a situation, the threshold value is changed to a small value, so that the number of cases where the required deceleration is less than the threshold value is reduced to prevent the automatic brake from operating frequently. Can do.
[0019]
On the other hand, when the error between the predicted value of the inter-vehicle distance between the host vehicle and the preceding vehicle after the predetermined time and the measured value is larger than the predetermined value, or when the relative acceleration is negative, it is not necessary to operate the automatic brake. Since it cannot be determined that there is, the threshold is not changed and the automatic brake can be operated without delay.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. However, FIG. 1 is a block diagram, and FIG. 2 is a flowchart for explaining the operation.
[0023]
As shown in FIG. 1, the inter-vehicle distance between the host vehicle and the preceding vehicle is detected by an inter-vehicle distance sensor 1 comprising a scan laser radar as inter-vehicle distance detection means. At this time, the inter-vehicle distance sensor 1 is irradiated with laser light in front of the own vehicle from the semiconductor laser of the scan laser radar as described above, and is scanned in the horizontal direction by a predetermined angle (for example, 0.1 °), and the reflection thereof. The distance between the vehicle and the preceding vehicle traveling in the same lane is detected from the time from when the light is received by the light receiver until the reflected light is received. Such inter-vehicle distance detection is periodically repeated every short time of about 100 ms.
[0024]
Further, a vehicle speed sensor 2 is provided as vehicle speed detecting means for detecting the host vehicle speed, and various switches 3 including a setting switch and a release switch for follow-up running control are also provided. Signals from these sensors 1 and 2 and various switches 3 are taken in by an electronic control unit (hereinafter referred to as ECU) 5, and each part is controlled by the ECU 5.
[0025]
Specifically, the ECU 5 determines whether or not the preceding vehicle is a preceding vehicle traveling in the same lane as the own vehicle, based on the detection result of the inter-vehicle distance from the vehicle traveling in front of the own vehicle by the inter-vehicle distance sensor 1. If it is determined that the vehicle is a preceding vehicle, based on the detected inter-vehicle distance detected by the inter-vehicle distance sensor 1 and the own vehicle speed by the vehicle speed sensor 2, the target inter-vehicle distance corresponding to the own vehicle speed and the preceding vehicle Acceleration / deceleration means for deriving the relative speed with respect to the vehicle, deriving the relative acceleration Ap of the preceding vehicle from the time change of the relative speed, and maintaining the actual detected inter-vehicle distance between the host vehicle and the preceding vehicle at the target inter-vehicle distance. Control of the electronic throttle 7 and the brake actuator 8, that is, the required acceleration and the required deceleration Ar for performing the opening control of the electronic throttle 7 and the drive control of the brake actuator 8. Perform out. Such derivation processing by the ECU 5 corresponds to derivation means in the present invention.
[0026]
Further, the ECU 5 has a function of calculating the gradient dAr of the required deceleration Ar, and when the derived required deceleration Ar falls below a predetermined threshold value Abr, the electronic throttle 7 and the brake actuator 8 that are acceleration / deceleration means. Control the deceleration.
[0027]
Further, the ECU 5 predicts the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time (for example, several seconds) from the detected inter-vehicle distance detected by the inter-vehicle distance sensor 1 and the relative speed of the preceding vehicle. The error (= | De |) from the actual measurement value is smaller than a predetermined value Demax that is determined in advance and the relative acceleration Ap of the preceding vehicle is positive, or the required deceleration rate Ar obtained by calculation for the past predetermined number of times. The threshold value Abr, which is a criterion for determining the required deceleration rate Ar, is set to a default value A0 (<0) and a correction value A1 (<0) on the condition that the average of the gradient dAr of FIG. ) Is added to a smaller value. In other words, for example, referring to FIG. 3, the threshold value Arth in FIG. 3 is lowered to the negative side. Here, it is preferable to experimentally obtain an optimal value in advance as the correction value A1.
[0028]
If this condition is a “variable condition”, this “variable condition” is satisfied when there is no need to operate the automatic brake as a situation of the preceding vehicle of the own vehicle. Therefore, when the “variable condition” is satisfied, the threshold value Abr is changed to a small value (Abr = A0 + A1), so that the number of cases where the required deceleration rate Ar falls below the threshold value is reduced, and the operation frequency of the automatic brake is reduced. .
[0029]
Such deceleration control of the electronic throttle 7 and the brake actuator 8 by the ECU 5 and processing for changing the threshold value Abr, which is a criterion for determining the magnitude of the required deceleration Ar, correspond to the control means in the present invention.
[0030]
Furthermore, an alarm unit 9 comprising an alarm buzzer, an alarm lamp, an LCD for displaying a predetermined message or a combination thereof is provided, and when the inter-vehicle distance from the preceding vehicle is too close to the target inter-vehicle distance, etc. The ECU 5 controls the notification unit 9, and the notification unit 9 is activated to issue a warning to the driver.
[0031]
Next, the operation processing procedure of the automatic brake will be described with reference to the flowchart of FIG. First, as shown in FIG. 2, the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time is predicted from the detected inter-vehicle distance detected by the inter-vehicle distance sensor 1 and the relative speed of the preceding vehicle. A value error (| De |) is derived, and it is determined whether this error is smaller than a predetermined value Demax (S1).
[0032]
If the decision result in the step S1 is YES, whether or not the relative acceleration Ap of the preceding vehicle derived from the inter-vehicle distance detected by the inter-vehicle distance sensor 1 and the own vehicle speed by the vehicle speed sensor 2 is greater than zero, that is, positive. If the determination result is YES, it is determined that the “variable condition” is satisfied, and the request derived based on the detected inter-vehicle distance by the inter-vehicle distance sensor 1 and the own vehicle speed by the vehicle speed sensor 2 is determined. The threshold value Abr, which is a criterion for determining the deceleration Ar, is changed to a value obtained by adding the correction value A1 to the default value A0 (S3).
[0033]
On the other hand, when the determination result of step S1 is NO and when the determination result of step S2 is NO, the process proceeds to step S4, and the average of the gradient dAr of the requested deceleration Ar obtained by the past predetermined calculation is the predetermined value. It is determined whether or not the gradient is smaller than dArmax (S4). If the determination result is YES, the “variable condition” is satisfied and the process proceeds to step S3 described above. If the determination result is NO, the “variable condition” is determined. Is not established and the routine proceeds to step S5, where the threshold value Abr, which is a criterion for determining the required deceleration Ar, is kept at the default value A0 (S5).
[0034]
Then, after the processing of step S3 and step S5 described above, the process proceeds to step S6, where it is determined whether the required deceleration rate Ar derived by the ECU 5 is below the threshold value Abr (S6). If the determination result is YES, the automatic brake flag Fbr is set to “1” as the need for automatic braking (S7), and if the determination result is NO, the automatic brake flag Fbr is set to “0”. Is set to "" (S8), and after the processes of steps S7 and S8, the operation is terminated.
[0035]
In this way, the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time t is predicted from the detected inter-vehicle distance detected by the inter-vehicle distance sensor 1 and the relative speed of the preceding vehicle, and an error between the predicted value and the actually measured value. (= | De |) is smaller than a predetermined value Demax and the relative acceleration Ap of the preceding vehicle is positive, or the average of the gradients dAr of the requested deceleration Ar obtained by a predetermined number of calculations in the past Is less than a predetermined gradient dArmax set in advance, the threshold value Abr, which is a criterion for determining the required deceleration rate Ar, is reduced to a value obtained by adding the correction value A1 to the default value A0 because the “variable condition” is satisfied. Be changed.
[0036]
Therefore, according to the above-described embodiment, when the variable condition is satisfied, the threshold value Abr, which is a criterion for determining the required deceleration rate Ar, is changed to a small value (Abr = A0 + A1). It is possible to prevent the automatic brake from operating frequently, and to prevent the driver from feeling uncomfortable.
[0037]
In the above-described embodiment, the case where the average of the gradient dAr of the required deceleration Ar obtained by the calculation for a predetermined number of times in the past is gentler than the predetermined gradient dArmax is described as the “variable condition”. It is not always necessary to add this condition.
[0038]
In the above-described embodiment, the case where it is determined whether the relative acceleration Ap of the preceding vehicle is positive (Ap> 0) as the “variable condition” has been described. However, the relative acceleration Ap is a predetermined value that is positive. It may be determined whether it is larger than the minimum value Apmin (> 0).
[0039]
Furthermore, in the above-described embodiment, the case where the inter-vehicle distance detection means is the inter-vehicle distance sensor 1 composed of a scan laser radar has been described, but the inter-vehicle distance detection means is not limited to such an inter-vehicle distance sensor 1. Of course.
[0040]
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.
[0042]
【The invention's effect】
As described above, according to the first and second aspects of the invention, the error between the predicted value and the measured value of the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time is smaller than the predetermined value, and the relative acceleration When is positive, it can be determined that it is not necessary to activate the automatic brake. In such a situation, the threshold value is changed to a smaller value, so the number of cases where the required deceleration is less than the threshold value is reduced and the automatic brake is Can be prevented from operating frequently, and safer driving can be assisted.
[0043]
On the other hand, when the error between the predicted value of the inter-vehicle distance between the host vehicle and the preceding vehicle after the predetermined time and the measured value is larger than the predetermined value, or when the relative acceleration is negative, it is not necessary to operate the automatic brake. Since it cannot be determined that there is, the threshold value is not changed, and the automatic brake can be operated without delay.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the embodiment of the present invention.
FIG. 3 is an operation explanatory diagram of a conventional example.
FIG. 4 is an operation explanatory diagram of another conventional example.
[Explanation of symbols]
1 Inter-vehicle distance sensor (inter-vehicle distance detection means)
2 Vehicle speed sensor (vehicle speed detection means)
5 ECU (derivation means, control means)
7 Electronic throttle (acceleration / deceleration means)
8 Brake actuator (acceleration / deceleration means)

Claims (2)

Detects the distance between the vehicle and the preceding vehicle traveling in the same lane, and performs acceleration / deceleration control of the acceleration / deceleration means to keep the vehicle distance at the target vehicle distance according to the vehicle speed and follow the preceding vehicle. In the traveling device,
An inter-vehicle distance detecting means for detecting an inter-vehicle distance between the host vehicle and the preceding vehicle at predetermined repetition times ;
Vehicle speed detecting means for detecting the own vehicle speed;
Wherein deriving the relative speed between the preceding vehicle and the subject vehicle and the inter-vehicle distance detecting following distance is detected for each by Ri said recurring time detecting means from the the vehicle speed by the vehicle speed detecting means, detecting for each of the repetition time Deriving means for deriving a required deceleration from the detected inter-vehicle distance and the relative speed, and deriving a relative acceleration of the preceding vehicle from the derived relative speed;
It is determined whether or not the required deceleration by the deriving means is below a predetermined threshold, and when the required deceleration is below the threshold, the acceleration / deceleration means is controlled to decelerate, and the repetition time From the detected inter-vehicle distance and the relative speed detected every time , the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time longer than the repetition time is calculated as the detected inter-vehicle distance and the relative speed × the predetermined time. predicting a predicted value by subtraction operation, the error between the predicted values and the measured value at a predetermined time has elapsed, it is determined whether or not the squid smaller than a predetermined value, the error is rather smaller than the predetermined value, And a control unit that changes the threshold value small on condition that the relative acceleration is positive when the predetermined time elapses . Detects the distance between the vehicle and the preceding vehicle traveling in the same lane, and performs acceleration / deceleration control of the acceleration / deceleration means to keep the vehicle distance at the target vehicle distance according to the vehicle speed and follow the preceding vehicle. In the control method of the traveling device,
The distance between the vehicle and the preceding vehicle is detected at predetermined repetition times ,
Detects the vehicle speed,
Deriving the relative speed between the own vehicle and the preceding vehicle from the detected inter-vehicle distance detected at each repetition time and the own vehicle speed, and from the detected inter-vehicle distance and the relative speed detected at each repetition time, Deriving the required deceleration and deriving the relative acceleration of the preceding vehicle from the derived relative speed,
It is determined whether or not the derived required deceleration is less than a predetermined threshold value, and when the requested deceleration is less than the threshold value, the acceleration / deceleration means is controlled to decelerate,
From the detected inter-vehicle distance and the relative speed detected at each repetition time , the inter-vehicle distance between the host vehicle and the preceding vehicle after a predetermined time longer than the repetition time is determined as the detected inter-vehicle distance and the relative speed × the predetermined speed. predicting a predicted value by subtraction calculation time and the error between the predicted values and the measured value at a predetermined time has elapsed, it is determined whether or not the squid smaller than a predetermined value, the error is above the predetermined value rather small, and the control method of the follow-up traveling device the relative acceleration at the time elapses the predetermined time on condition that a positive, and changes reduce the threshold.

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