JPH04244432A - Traveling controller for vehicle - Google Patents

Abstract

PURPOSE:To avoid the generation of uncomfortable jerky feeling in traveling in cities where there is much traffic by eliminating driver's judgment and operation during performing the auto cruising keeping the distance between vehicles constant. CONSTITUTION:In a traveling controller for a vehicle which performs the auto cruising keeping the distance between vehicles constant, an objective distance between vehicles setting means 15 for setting an objective distance between vehicles is provided with a change frequency judging section 17 for judging the frequency of the change of the distance between the vehicle which performs the auto cruising and the vehicle which travels forward the aforementioned vehicle, which is detected by a distance between vehicles detecting means 4, and a zonal adjusting section 18 for expanding the lower limit area of an objective distance between vehicles when the frequency of the change of the distance between the aforementioned vehicle and the vehicle traveling forward the aforementioned vehicle is more than the specified frequency. The zonal adjusting section 18, when the frequency of the change of the distance between the aforementioned vehicle and the vehicle traveling forward the aforementioned vehicle is more than the specified frequency, expands the lower limit area of the objective distance between the aforementioned vehicle and the vehicle traveling forward the aforementioned vehicle allowing the vehicle to shorten the distance between the vehicles to the access limit without driver's judgment and operation and to obtain smooth driving to the exclusion of breaking into a queue.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle running control device, and more particularly, to a vehicle that controls the running speed of its own vehicle so that the distance between the vehicle and the vehicle traveling in front becomes a set target value. The present invention relates to a travel control device for use in vehicles.

0002

2. Description of the Related Art Vehicles such as automobiles are now equipped with vehicle cruise control devices called auto-cruise devices that allow drivers to set the speed of the vehicle as they wish. This device is equipped with a set switch to set and increase the target vehicle speed, a coast switch to decelerate, and a resume switch to return to the vehicle speed under conventional constant speed driving control. ,
The driver can now drive the vehicle at any desired speed by manually operating a switch, without having to operate the accelerator pedal. Recently, a so-called inter-vehicle distance auto-cruise device has also been proposed which also performs inter-vehicle distance control so that the inter-vehicle distance from the vehicle in front becomes a target inter-vehicle distance. In other words, this device is equipped with an inter-vehicle distance detection means to measure the inter-vehicle distance to the vehicle in front, and also sets a safe inter-vehicle distance based on the traveling speed of the own vehicle and the relative speed to the vehicle in front. Driving control is performed with the following distance as a target.

0003

[Problems to be Solved by the Invention] However, with the above-described auto-cruise control, when driving in urban areas with heavy traffic, it is difficult to detect other vehicles within a set target distance. may allow forcible interruptions. In such cases, the vehicle decelerates suddenly, resulting in a jerky driving sensation. Furthermore, by allowing other vehicles to cut in relatively easily, the driver may feel psychologically irritated. For this reason, for example, in Japanese Patent Application Laid-open No. 61-6031,
An example of an inter-vehicle distance control device that is capable of changing or adjusting an inter-vehicle distance to a vehicle traveling in front according to the current driving condition is described. However, in this type of control device, the judgment for adjusting the inter-vehicle distance is left to the driver's subjectivity, and the adjustment is made by the driver's operation via a manual adjustment means. Therefore, there is a risk that operations may be troublesome and errors in judgment of the situation may occur, and improvements are desired. The present invention has been made in consideration of these circumstances, and its purpose is to eliminate the unpleasant jerky driving feeling when driving in a city with heavy traffic, without requiring the driver's judgment or operation when performing inter-vehicle distance auto-cruise. It is an object of the present invention to provide a vehicle travel control device that does not cause the occurrence of.

0004

[Means for Solving the Problems] The present invention includes an inter-vehicle distance detecting means for detecting an inter-vehicle distance to a vehicle traveling ahead, and a target inter-vehicle distance setting means, and the present invention provides a means for determining an inter-vehicle distance to a predetermined target distance from a vehicle traveling ahead. The present invention is applied to a vehicle travel control device that performs inter-vehicle distance control to control the traveling speed of the vehicle so that the inter-vehicle distance set as a target is reached when the distance is within the distance band. Its features are that the target inter-vehicle distance setting means includes a change frequency determination means for determining the frequency of change in the inter-vehicle distance to the vehicle running ahead detected by the inter-vehicle distance detection means, and a change frequency determination means for determining the frequency of change in the inter-vehicle distance to the vehicle running ahead detected by the inter-vehicle distance detection means. A band adjustment unit is provided that expands the lower limit area of the target inter-vehicle distance band when the frequency is equal to or greater than a predetermined number of times. Furthermore, when the frequency of change in the inter-vehicle distance from the vehicle in front is greater than or equal to a predetermined number of times, the band adjustment section may perform a control function to shift the target inter-vehicle distance band to a direction in which the inter-vehicle distance becomes shorter. good.

[0005]

[Operation] If the frequency of change in the inter-vehicle distance to the vehicle traveling ahead detected by the change frequency determining means is equal to or greater than a predetermined number of times,
The band adjustment section expands the lower limit region of the target inter-vehicle distance band set for performing inter-vehicle distance control. This narrows the dead zone in which inter-vehicle distance control is not performed, shortens the inter-vehicle distance at which the vehicle can approach the vehicle traveling ahead, and reduces the tolerance for other vehicles to cut in. Furthermore, when the frequency of change in the inter-vehicle distance to the vehicle traveling ahead is greater than or equal to a predetermined number of times, the band adjustment section controls the target inter-vehicle distance band itself to shift to a direction in which the inter-vehicle distance becomes shorter, and inter-vehicle distance control is started. The inter-vehicle distance can also be shortened, and a more appropriate inter-vehicle distance control state can be achieved.

[0006]

Effects of the Invention In the vehicle travel control device of the present invention, the target inter-vehicle distance setting means includes a change frequency determination section that determines the frequency of change in the inter-vehicle distance to the vehicle traveling ahead detected by the inter-vehicle distance detection means; The system is equipped with a band adjustment section that expands the lower limit of the target inter-vehicle distance band when the frequency of changes in the inter-vehicle distance to the traveling vehicle exceeds a predetermined number of times, so when there is heavy traffic, the driver does not need to operate based on his/her judgment. By shortening the inter-vehicle distance at which the driver can approach the vehicle traveling ahead, it is possible to suppress jerky and unpleasant behavior without allowing inadvertent interruptions. Furthermore, when the frequency of change in the inter-vehicle distance to the vehicle in front is greater than or equal to a predetermined number of times, the band adjustment unit may be configured to shift the target inter-vehicle distance band itself to the direction in which the inter-vehicle distance becomes shorter. The inter-vehicle distance at which distance control is started can also be shortened, and inter-vehicle distance control can be started more appropriately.

[0007]

EXAMPLES The present invention will be explained in detail below based on examples thereof. The vehicle cruise control device shown in this example performs so-called inter-vehicle distance auto-cruise control, and in order to suppress jerky and unpleasant behavior without allowing inadvertent interruptions, the following measures are taken: It is configured. As shown in FIG. 1, a control unit 1 consisting of a microcomputer includes a calculation section 2 that performs various calculations for auto-cruise control of inter-vehicle distance, and a storage section 3 that stores programs necessary for the calculations.
and an input/output circuit (not shown). On the input side, there is a following distance detecting means 4 for detecting the following distance from the vehicle traveling ahead, a set switch 7 as a target vehicle speed setting means for setting a target vehicle speed, and a set vehicle speed set by the set switch 7. A coast switch 8 as a deceleration operation means for decelerating the vehicle, a resume switch 9 for returning the vehicle speed to the previous constant speed cruise control, a vehicle speed sensor 11, a main switch (not shown), etc. are connected. On the other hand, a step motor 13 serving as an actuator for operating the throttle valve 12 is connected to the output side. As is well known, the circuit within the calculation unit 2 includes the following:
Target inter-vehicle distance setting means 15 for calculating a target inter-vehicle distance and setting the value for performing inter-vehicle distance auto-cruise control, and ASC control for controlling inter-vehicle distance auto-cruise and normal auto-cruise. Means 1
6. The ASC control means 16 is provided with a control system changing means 14 for instructing switching between the following distance auto-cruise control system and the normal auto-cruise control system. In this example, the target inter-vehicle distance setting means 15 includes a change frequency determining section 17 for determining the frequency of change in the inter-vehicle distance from the preceding vehicle detected by the inter-vehicle distance detecting means 4; A band adjustment unit 18 is provided that instructs to expand the lower limit region of the target inter-vehicle distance band when the frequency of change in the inter-vehicle distance from the vehicle is equal to or greater than a predetermined number of times. With this configuration, the target inter-vehicle distance setting means 15 sets the target inter-vehicle distance based on the vehicle speed of the own vehicle at that time and the relative speed of the vehicle traveling ahead. On the other hand, the inter-vehicle distance is measured by the inter-vehicle distance detection means 4, and the ASC control means 16 uses the difference value between the actual inter-vehicle distance and the target inter-vehicle distance to maintain the inter-vehicle distance to the vehicle running ahead at the target inter-vehicle distance at all times. Following distance auto-cruise control and normal auto-cruise control are performed. Then, the change frequency determination unit 17
When it is detected that the frequency of change in the inter-vehicle distance from the vehicle traveling ahead is equal to or greater than a predetermined number of times, a command is issued to operate the band adjustment unit 18 to expand the lower limit region of the target inter-vehicle distance band in which inter-vehicle distance control is performed. is emitted. As a result, the dead zone in which the following distance is not controlled (see area α in FIG. 4, which will be described later) becomes narrower, reducing the distance between vehicles that can approach the vehicle in front and reducing the tolerance for other vehicles to cut in. , it is possible to eliminate the jerky running feeling. To explain in detail, as the inter-vehicle distance detecting means 4, a radio wave measuring means such as an FM-CW radar method using microwaves is employed. This measures the inter-vehicle distance by projecting FM waves onto the vehicle traveling ahead, which is the object of measurement, and receiving the directly reflected direct waves using a receiving antenna. As is well known, the target inter-vehicle distance setting means 15
When the distance between the vehicle and the vehicle in front is within a predetermined distance, that is, within the target distance band, the system performs auto-cruise based on the relative speed of the vehicle and the vehicle in front. calculate the target inter-vehicle distance and set that value. That is, if the vehicle speed at that time is, for example, 40 km/h, the control target inter-vehicle distance at that time corresponding to point L in FIG. 4 is calculated, and travel control is performed such that the vehicle speed maintains that inter-vehicle distance. I'm trying to make it happen. The ASC control means 16 performs control for auto-cruising the following distance so that the following distance is set as a target, and arbitrarily sets the vehicle speed.
It also maintains the set vehicle speed, performs normal autocruise controls such as acceleration, deceleration, and returning to the previous speed. Switching of these control systems is performed by the control system changing means 14 according to a pre-stored program, and both controls can be easily performed by manually operating switches 7 to 10 without operating the accelerator pedal. be called. A change frequency determination unit 17 provided in the target inter-vehicle distance setting means 15 determines the current traffic volume by detecting the degree of change in the inter-vehicle distance from the vehicle traveling ahead detected by the inter-vehicle distance detection means 4. To detect. In other words, when the frequency of changes in the inter-vehicle distance occurs more than a predetermined number of times within a predetermined period of time, it is determined that the traffic volume is so large that there is a concern about interruptions. At that time, the band adjustment unit 18 is operated to expand the lower limit region of the target inter-vehicle distance band set for performing inter-vehicle distance auto-cruise control. A normal target inter-vehicle distance band is set so as to spread radially according to the vehicle speed, as shown in a region M shown by solid hatching in FIG. 4. The upper solid line 19 indicates the inter-vehicle distance at which inter-vehicle distance control is started, and the lower solid line 20 indicates the inter-vehicle distance at which the vehicle can approach the vehicle traveling ahead. During this time, control for auto-cruising the inter-vehicle distance is performed, and the lower the speed, the narrower the band and the shorter the inter-vehicle distance. In other words, when driving on a highway or the like, the setting is such that a larger distance between vehicles is obtained to ensure sufficient safety, and as the speed decreases, the distance between vehicles is reduced. However, especially when driving in urban areas with heavy traffic, as mentioned above, inadvertent interruptions may be allowed within the target inter-vehicle distance band. The driving control for maintaining the vehicle may result in a jerky driving feeling. Therefore, in order to solve this problem, when the traffic volume is heavy, the band adjustment unit 18 expands the lower limit area of the target inter-vehicle distance band downward as shown by the broken line 21 at a predetermined speed, for example, 60 km/h or less. let In other words, by widening the target inter-vehicle distance band as shown in area N indicated by dashed hatching and shortening the approachable inter-vehicle distance to the vehicle traveling in front, the inter-vehicle distance is narrowed and cut-ins are eliminated. . As a result, for example, the vehicle speed is 4
In the case of 0 km/h, the dead zone α where the inter-vehicle distance is not controlled can be intentionally narrowed to become the dead zone β.

[0008] A basic preferred example of travel control by the present device will be explained step by step based on the flowcharts shown in FIGS. 2 and 3. First, while driving, a vehicle speed detection signal from the vehicle speed sensor 11 is detected by the target inter-vehicle distance setting unit 1.
5 [Step 1, hereinafter referred to as S1, etc.]. If the main switch is on [S2], the presence or absence of rain is asked [S3], and if there is no rain, the on/off of the set switch 7, coast switch 8, resume switch 9 is asked [S4, S5. S6], and if both of them are off, the inter-vehicle distance is measured by the inter-vehicle distance detection means 4 [S7], and a control operation for auto-cruise control of the inter-vehicle distance is started. If the main switch is off in step 2, after performing main off processing,
S16], and if there is rain in step 3, the vehicle shifts to normal driving without performing inter-vehicle distance auto-cruise control [S17]. Note that rain can be determined based on the level of the measurement signal from the radio-based inter-vehicle distance detection means 4. If there is rain, the measurement signal level will drop and accurate measurements will not be possible.
In such cases, auto cruise control is not performed and normal driving is performed. In step 7,
DIS when the inter-vehicle distance is within a predetermined short range after the inter-vehicle distance is measured by the inter-vehicle distance detection means 4
It is asked whether the T short F (flag) is set to 1 [S8]. 1, and if the vehicle speed at that time is 60 km/h or less [S9], the absolute value of the change in inter-vehicle distance within a predetermined time, that is, the difference ΔDt from the previous inter-vehicle distance within each unit time. sum B
U is calculated [S10], and the BU value is set to a predetermined value ΔD
It is compared with IST [S11]. Further, when the DIST short flag is not set to 1 [S8], and when the vehicle speed is 65 km/h or less [S21], the above comparison is made in the same way. If the BU value is larger than ΔDIST, it is determined that the traffic volume is such that it is necessary to adjust the target inter-vehicle distance band of the inter-vehicle distance. Then, the band adjustment unit 18 issues an adjustment command to expand the lower limit region of the target inter-vehicle distance band (see the change from the solid line 20 to the broken line 21 in FIG. 4) [S12]. D
If 1 is not set in IST short F, 1
[S13], and the AS
Vehicle distance control and vehicle speed control are performed by the C control means 16 [S14]. Through this corresponding output processing, inter-vehicle distance auto-cruise control is achieved without any jerky feeling [S15
]. In other words, by expanding the lower limit region of the target inter-vehicle distance band, it is possible to reduce the inter-vehicle distance, prevent unnecessary interruptions, and eliminate the jerky driving feeling. In step 8 described above, if the DIST short flag is not set to 1 and the vehicle speed is not 65 km/h or less [S21], or even if the DIST short flag is set to 1 [S8], the vehicle speed is 60k
m/h or less, a normal target inter-vehicle distance band indicated by a solid hatched area M is set [S22
]. After that, if the DIST short flag has not been reset to 0, it is set to 0 [S23], the ASC control means 16 performs vehicle distance control and vehicle speed control [S14], and the corresponding output processing [S15] returns the normal Inter-vehicle distance auto-cruise control is performed. on the other hand,
In steps 4 to 6, set switch 7, coast switch 8, resume switch 9 [S6
] is on, the control system changing means 14 switches the control system of the ASC control means 16,
Corresponding set acceleration processing [S18], coast processing [S
19] or resume processing [S20] is performed, and normal auto-cruise is performed by the output processing [S13]. By the way, in this example, from step 8 to step 9 or from step 8 to step 21
In the process of determining the frequency of change leading to step 11, the reference value 60 of the vehicle speed for operating the band adjustment section 18 is determined.
A slight hysteresis is provided with respect to km/h so that the target inter-vehicle distance band can be smoothly adjusted in the boundary area. In other words, even if the DIST short flag is not set to 1 in step 8, the 60km
/h (65 km/h or less) [S11], the band adjustment unit 17 adjusts the target inter-vehicle distance band, and thereby shifts to normal inter-vehicle distance auto-cruise control. [S22] The approachable inter-vehicle distance is smoothly adjusted in a transient manner. As described above, according to the vehicle travel control device of this example, by providing the change frequency determining section 17 in the target inter-vehicle distance setting means 15, the frequency of change in the inter-vehicle distance with respect to the vehicle traveling ahead is detected. . Then, if the frequency of change is more than a predetermined number of times within a predetermined time, the band adjustment section 18 is activated,
The lower limit region of the target inter-vehicle distance band in which inter-vehicle distance control is performed is expanded. This reduces the distance between the vehicle and the approaching vehicle in front, reduces the tolerance for other vehicles to cut in, and eliminates the jerky feeling of driving, without requiring any judgment or operation by the driver. FIG. 5 shows a different embodiment, in which the functions of the band adjustment section 18 are shown by solid lines 19,
The target inter-vehicle distance band itself indicated by solid hatching surrounded by 20 is shifted to a lower inter-vehicle distance like the band indicated by broken line hatching surrounded by broken lines 19a and 20a. Therefore, when the traffic volume is heavy, the approachable inter-vehicle distance shown by the lower solid line 20 and the inter-vehicle distance at which control is started, shown by the upper solid line 19, are shifted downward as shown by broken lines 20a and 19a, respectively. This allows for more appropriate responses to be taken. In other words, since the inter-vehicle distance at which control starts is shifted downward, inter-vehicle distance auto-cruise control can be started at a more appropriate timing and without waste.

As described above, according to the vehicle cruise control device of the present invention, the target inter-vehicle distance setting means for calculating the target inter-vehicle distance for performing inter-vehicle distance autocruise and setting the value; A change frequency determination unit that determines the frequency of change in the distance between the vehicle and the vehicle running ahead detected by the vehicle distance detection means; Since the vehicle is provided with a band adjustment section that expands the lower limit area of the distance band, when the traffic volume is heavy, the approachable inter-vehicle distance can be shortened without requiring judgment or operation by the driver. This prevents inadvertent interruptions and provides a smooth, jerky driving feel. Further, the same effect can be exerted when the band adjustment section shifts the target inter-vehicle distance band to a direction in which the inter-vehicle distance becomes shorter when the frequency of change in the inter-vehicle distance from the vehicle traveling ahead is equal to or greater than a predetermined number of times. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a vehicle travel control device according to the present invention.

FIG. 2 is the first half of a flowchart for explaining travel control.

FIG. 3 is the second half of a flowchart for explaining travel control.

FIG. 4 is a graph showing a target inter-vehicle distance band corresponding to vehicle speed.

FIG. 5 is a graph showing target inter-vehicle distance bands corresponding to vehicle speeds in different examples.

[Explanation of symbols]

4 - Inter-vehicle distance detection means, 15 - Target inter-vehicle distance setting means,
17--Change frequency determination section, 18-- Bandwidth adjustment section.

Claims (2)

[Claims] [Claim 1] Comprising: inter-vehicle distance detection means for detecting an inter-vehicle distance to a vehicle traveling ahead; and target inter-vehicle distance setting means,
When the distance between the vehicle and the vehicle in front falls within a predetermined target distance band, the system automatically adjusts the distance between the vehicle and the vehicle ahead to reach the target distance.
In the vehicle travel control device that controls the traveling speed of a vehicle, the target inter-vehicle distance setting means includes a change frequency determination unit that determines the frequency of change in the inter-vehicle distance from the preceding vehicle detected by the inter-vehicle distance detection means; 1. A vehicle travel control device comprising: a band adjustment section that expands a lower limit region of a target inter-vehicle distance band when the frequency of change in inter-vehicle distance from a vehicle running ahead is equal to or greater than a predetermined number of times. 2. Comprising: inter-vehicle distance detection means for detecting an inter-vehicle distance to a vehicle traveling ahead; and target inter-vehicle distance setting means,
When the distance between the vehicle and the vehicle in front falls within a predetermined target distance band, the system automatically adjusts the distance between the vehicle and the vehicle ahead to reach the target distance.
In the vehicle travel control device that controls the traveling speed of a vehicle, the target inter-vehicle distance setting means includes a change frequency determination unit that determines the frequency of change in the inter-vehicle distance from the preceding vehicle detected by the inter-vehicle distance detection means; A vehicle travel control device comprising: a band adjustment section that shifts a target inter-vehicle distance band to a direction in which the inter-vehicle distance becomes shorter when the frequency of change in the inter-vehicle distance with respect to a vehicle traveling in front is equal to or greater than a predetermined number of times. .