JP2940174B2 - Travel control device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling control device for a vehicle, and more particularly to a device for controlling traveling of a vehicle in a general urban area having a downhill road or the like.

[0002]

2. Description of the Related Art Hitherto, a control device for driving a vehicle at a constant speed at a set speed has been developed in order to improve driving operability particularly on a highway.

A device of this type is disclosed in, for example,
2. Description of the Related Art A vehicle travel control device disclosed in Japanese Patent Application Publication No. 215432 is known. The purpose of this vehicle travel control device is to maintain the own vehicle speed at the set vehicle speed or to maintain the inter-vehicle distance at the safe inter-vehicle distance without the driver operating the accelerator, and to calculate the safe inter-vehicle distance from the own vehicle speed. Provide a preceding vehicle detecting means for detecting the presence of a leading vehicle in the vehicle, control the own vehicle speed so that the inter-vehicle distance becomes the safe inter-vehicle distance when there is a preceding vehicle, and when there is no preceding vehicle The vehicle travels while controlling the own vehicle speed to the set vehicle speed.

[0004]

However, such a conventional apparatus is mainly intended for control on a highway, and the emphasis of the system is on acceleration control for controlling a throttle. When such a conventional device is applied to running in an urban area, the distance between the vehicle and the preceding vehicle is shorter in an urban area than in a highway, and the driver frequently performs a brake operation. The control with emphasis did not match the driving sensation of the driver, and there was a problem that comfortable driving could not always be guaranteed.

[0005] For example, when traveling on a downhill road in a general urban area, the driver travels in consideration of acceleration of the host vehicle without operating the accelerator, and the distance between the vehicle and the preceding vehicle is large. Even in the case where the vehicle follows the preceding vehicle without operating the accelerator, and considering that the own vehicle is naturally accelerated even if the inter-vehicle distance with the preceding vehicle is the safe inter-vehicle distance on a flat road The brake operation is performed. Thus, on a downhill road,
Drivers should drive safely with more emphasis on inertial driving and brake control than throttle control.In such a case, if the control with the above-mentioned conventional device is performed, the driver will not match the actual driving feeling , There was a problem that the automatic control mode had to be released by frequently performing the brake operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a vehicle travel control device capable of performing automatic travel more suited to a driver's driving sensation even in a general urban area including a downhill road or the like. Is to provide.

[0007]

In order to achieve the above object, a traveling control device for a vehicle according to the present invention comprises a distance detecting means for detecting an inter-vehicle distance to a preceding vehicle, and a vehicle speed detecting means for detecting a vehicle speed of the own vehicle. means and an operation detecting means for detecting the presence of the accelerator operation and brake operation, even if the accelerator operation and brake operation without is detected by the operation detecting means, when the preceding vehicle is present the operation detection Contact at the time the accelerator operation and brake operation without is detected by means
Kicking controls the brake of the headway time as the control target value, the vehicle speed at which the accelerator operation and brake operation without at the operation detection unit when the preceding vehicle is not present is detected
Control means for controlling the brake as a control target value .

[0008]

The vehicular travel control device of the present invention has such a structure, and automatically performs a brake operation in coasting traveling without operating an accelerator or a brake on a downhill road in a general urban area. .

Here, headway time T is an amount obtained by evaluating the inter-vehicle distance to the preceding vehicle in units of time, and is defined as T = KL / V (K is a constant), where L is the inter-vehicle distance and V is the own vehicle speed. Is done.

When a preceding vehicle is present during coasting on a downhill road or the like , the accelerator operation and the brake operation are performed .
The time when no operation is detected, that is, the headway time with the preceding vehicle at the start of coasting is set as the control target,
The brake is controlled so as to maintain the vehicle speed, and if there is no preceding vehicle , the vehicle speed at the start of coasting is set as the control target.
By controlling the brake so that the vehicle speed is lower than this vehicle speed , the driving feeling of the actual driver when traveling downhill
This is to drive in accordance with the sense of sight.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a vehicle travel control device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall configuration diagram of this embodiment, which is composed of two systems, an acceleration system and a deceleration system.

In the acceleration system, the engine throttle 12 is opened and the vehicle is accelerated by operating the accelerator pedal 10 by the driver as in the prior art.

On the other hand, the deceleration system is further divided into two systems, a first system for operating a brake oil pressure by operating a brake pedal 14 by a normal driver, and a hydraulic valve 18 operated by a control signal from a control device 16. And a second system for controlling brake hydraulic pressure. These two speed reduction systems are connected to a brake 22 via a change valve 20.
And is decelerated by the driver's operation of the brake pedal or by automatic control from the control device 16.

Here, the change valve 20 compares the hydraulic pressure by the driver's operation of the brake pedal with the hydraulic pressure by the control device 16 and uses the higher hydraulic pressure to set the brake 2.
2 is provided with a selection mechanism for actuating the device.

FIG. 2 is a view for explaining the operation of the change valve 20. From time t _{0 to} t _{2, the} brake oil pressure by the operation of the brake pedal 14 by the driver is 0 (), while the brake oil pressure is increased by the control signal from the control device 16 (), and is applied to the brake 22 during this time. The brake oil pressure is higher, that is, the brake oil pressure by the control device 16 ().

From time t _{2 to} time t ₃ , an increase in the brake oil pressure due to the driver's operation of the brake pedal is observed. However, the brake oil pressure by the driver operation is lower than the brake oil pressure by the control device 16. The brake hydraulic pressure applied to 22 is the system of the control device 16, that is, the system in the figure.

The time _t 3 ~t higher than the brake hydraulic pressure of the brake oil pressure towards the control device 16 by the driver of the operation in the _4, thus change valve 20 the control unit 16
The brake hydraulic pressure is converted from the control system to the control driver system, and the brake 22 is operated based on the driver's operation.

As described above, the change valve 20 operates the brake by selecting one of the two systems having a higher brake hydraulic pressure, thereby ensuring high reliability.

FIG. 3 is a block diagram showing the configuration of the control device 16. The control device 16 includes various sensors and a coast control ECU (electronic control device) that performs arithmetic processing of signals from these sensors. The control device 16 controls the hydraulic valve 18 according to the result of the arithmetic processing, and further includes a buzzer, a brake lamp, and the like. To alert the driver of the own vehicle or the driver of the following vehicle.

In this embodiment, an inter-vehicle distance sensor 16a, a vehicle speed sensor 16b, an accelerator switch 16c, and a brake switch 16d are provided as sensors. The inter-vehicle distance with the preceding vehicle, the vehicle speed of the host vehicle, and the accelerator operation of the driver are respectively provided. And the presence or absence of a brake operation are detected. Then, detection signals from these sensors are input to the coast control ECU 16f, and predetermined arithmetic processing is performed.

As the inter-vehicle distance sensor 16a, a millimeter wave radar, a laser radar, a CCD camera or the like can be used, and as the vehicle speed sensor 16b, a sensor for detecting the output rotation speed of the transmission or a sensor for detecting the rotation speed of the wheels. Can be used. As the accelerator switch 16c, a switch attached to the accelerator pedal 10 or a switch for detecting the idling state of the throttle can be used.
As 6d, a switch attached to the brake pedal 14 or a switch for detecting the lighting of a brake lamp can be used.

Further, a set switch 16e for starting the operation of the apparatus of this embodiment is also provided at a predetermined position, for example, in the vicinity of the driver's seat. The set switch 16e causes the coast control ECU 16f to be described later based on a detection signal input thereto. This is a configuration for performing arithmetic processing. And
The calculation processing result is output as control of brake hydraulic pressure, a buzzer for notifying the driver that the coasting control is being performed, and lighting of a brake lamp for notifying the following vehicle that the coasting control is being performed.

Hereinafter, the coast control ECU 1
The operation of 6f will be described in detail with reference to a flowchart.

FIG. 4 shows the coast control ECU 16.
The control flowchart of f is shown. First, S10
At 1, data is read from each sensor. Then, in the next S102, the set switch 16e is turned ON and O.
If FF is determined and YES is determined in S102, that is, if the set switch 16e is ON, the process proceeds to S103.

In S103 and in the next S104, it is determined whether or not the vehicle is coasting. That is,
In S103, it is determined whether or not the accelerator is fully closed,
In S104, it is determined whether or not the brake is fully closed. If YES is determined in both S103 and S104, it means that the driver has not operated any of the accelerator and the brake, and that the vehicle is currently coasting.

When YES is determined in S103 and S104, the process proceeds to the next S105, and the flag fg is determined. Since the flag fg = 00 in the initial state, the determination is NO in this step, and the flow shifts to S106.

In step S106, the flag fg is changed from 00 to f.
g is set to 01, and steps S101 to S105 are repeated again.

As described above, once in step S106, the flag fg =
After being set to 01, YES is determined in S105, and the routine goes to the next step S108.

In S108, it is determined whether there is a preceding vehicle. To determine whether there is a preceding vehicle, the following distance sensor 16 is used.
What is necessary is just to determine based on the detection signal from a. That is,
If the preceding vehicle is detected by the detection capability of the inter-vehicle distance sensor 16a, it is determined in S108 that there is a preceding vehicle, and if not, it is determined that there is no preceding vehicle. If it is determined in S108 that there is a preceding vehicle, the process proceeds to S109, and the value of the flag fg is determined again.

In this case, since the value of the flag fg is set to 01 in S106, NO in this step S109
And fg = FF is set in the next S110,
Further, after the control value is set to a predetermined value in the next S111, the process proceeds to S112. On the other hand, if YES in S109, that is, if the flag fg is already set to FF, the flow shifts to S112 without going through S110 and S111.

In step S112, deceleration control is performed so that the inter-vehicle distance to the preceding vehicle detected in step S108 is equal to or longer than the headway time at the start of coasting.

Hereinafter, the control process performed in S112 will be described in detail with reference to FIG. In FIG. 5, first, it is determined whether or not the vehicle speed v detected by the vehicle speed sensor 16b is _{equal to} or higher than a predetermined minimum vehicle speed _vmin . This S201
If it is determined to be YES, the process proceeds to S202, and the headway time T expressing the inter-vehicle distance L in units of time is calculated. This headway time T is, as is clear from the definition, T
= KL / v. Here, K is a constant.

[0034] After the headway time T is calculated in S202, comparison between headway time T ₀ at the next S203, the headway time T and the inertia running start is performed. The coasting starting time headway _{T 0} is calculated by _{T 0 = K · L 0 /} v 0 from inter-vehicle distance _{L 0} and the vehicle speed _{v 0} at the start coasting, headway time _{T 0} or the time of the coasting start The deceleration control is performed so that That is, NO in S203, that is, the headway time T is equal to the headway time T
If it is determined that greater than _0, the process proceeds to S204 and the brake operation amount VB = 0, whereas YES at S203, that is, the headway time T is determined to headway time _{T 0} following the next step S205 Brake operation is performed and deceleration control is performed.

The difference between the time headway T ₀ to be the S205 calculated headway time T and the target in, and the brake operation amount according to the difference between the headway time T and the previous time headway T _-1 is determined. That is, constants K1 and K2, the brake operation amount is determined by _{VB = K1 (T 0 -T)} -K2 (T-T -1).

After the brake operation amount VB is determined in S204 or S205, the flow shifts to the next S206, where the current headway time T is replaced with T- _1, and the above steps are repeated again.

On the other hand, when the vehicle speed v is equal to or less than the predetermined minimum vehicle speed v _min is at S201, the process proceeds to S207, the current vehicle distance L and a predetermined minimum headway distance L _min
Is determined. The comparison between the inter-vehicle distance L and the minimum inter-vehicle distance L _min is performed when the vehicle speed v is extremely small, such as when the vehicle speed is determined to be equal to or less than the predetermined minimum vehicle speed v _min in S201. This is because the headway time is not controlled from the viewpoint of safety, but is controlled so that the inter-vehicle distance is directly equal to or more than the minimum inter-vehicle distance L _min which is a dangerous inter-vehicle distance.

If NO in S207, that is, if it is determined that the current inter-vehicle distance L is larger than the minimum inter-vehicle distance L _min , the flow shifts to S208, and the brake operation amount VB = 0. On the other hand, if YES is determined in S207,
Brake operation amount corresponding to the difference between the minimum inter-vehicle distance L _{mi n} and inter-vehicle distance L is calculated in S209. That is, with K3 as a constant, the brake operation amount is determined by VB = K3 ( _Lmin- L).

As described above, in the headway control process in S112, when the vehicle speed v is equal to or higher than the predetermined value, the deceleration control is performed so as to be equal to or longer than the headway time at the start of coasting, or the vehicle speed v is equal to or lower than the predetermined value. In the case of, the deceleration control is performed so as to exceed the minimum inter-vehicle distance, and the vehicle follows the preceding vehicle safely.

On the other hand, if it is determined in S108 of FIG. 4 that there is no preceding vehicle, the flow shifts to S113 and the flag fg is again set.
Is determined. If it is determined in step S113 that the value of the flag fg is 0FF, the flag is newly set to fg = 0F in the next step S114, and the control value is set to a predetermined value in step S115. Thereafter, the flow shifts to the vehicle speed control processing in S116. On the other hand, the flag fg is set to 0 in S113.
If it is determined to be F, the flow shifts to S116 without going through S114 and S115.

In S116, unlike the inter-vehicle control process in S112, the vehicle speed is decelerated so as to be equal to or lower than the vehicle speed at the start of coasting. Hereinafter, this vehicle speed control process will be described in detail with reference to FIG.

[0042] FIG. 6 there is shown a flowchart of the vehicle speed control process, the magnitude of the vehicle speed v ₀ at the vehicle speed v and the inertia running start is determined first at S301. This S30
If the answer is 1 in NO, that is, if the vehicle speed v is lower than the target vehicle speed v ₀ at the start of the coasting, the process proceeds to S302 and the brake operation amount VB = 0 is determined. On the other hand, S3
01 is YES, that is, the vehicle speed v ₀ at which the vehicle speed v is the target.
In a case where it is determined that more than the difference between the vehicle speed v and the target vehicle speed v ₀ at the next S303, and the brake operation amount according to the difference between the vehicle speed v and the previous vehicle speed v _-1 is determined. That is, K
4, the brake operation amount is determined by VB = K4 (v−v ₀ ) + K5 (v−v ₋₁ ), where K5 is a constant. And S302
Alternatively, after the brake operation amount VB is determined in S303, the process is repeated in S304, replacing the current vehicle speed v with v- ₁ .

As described above, in the vehicle speed control process of S116, the brake operation amount is determined so that the vehicle speed becomes equal to or lower than the vehicle speed at the start of coasting, and deceleration control is performed.
Even when there is no preceding vehicle, the vehicle can travel safely.

As described above, during the coasting without the accelerator and the brake operation, the inter-vehicle control or the vehicle speed control is performed according to the presence or absence of the preceding vehicle. However, the coasting is performed by the driver performing the accelerator operation or the brake operation. When the setting is canceled or when the set switch 16e is turned off to stop the operation of the apparatus of the present embodiment, the following processing is performed.

That is, when the set switch 16e is turned off and when the driver operates the accelerator, NO is determined in S102 and S103, respectively, and the process proceeds to S117. In this step S117, the brake operation amount VB =
The flag is set to 0, and a flag fg = 00 indicating that the vehicle is not coasting is set in the next S119.

When the driver operates the brake, the determination in S104 is NO, and the flow shifts to S118. In this S118, VB should be set to VB = 0 because the deceleration control in the coasting control is not performed. However, if the brake control amount suddenly becomes 0, it is inconvenient both in terms of safety and driving feeling , so that the brake control is performed stepwise. V to reduce the amount
The process proceeds to S119 with B = 0.5 VB.

As described above, the coast control ECU 16f of this embodiment performs the deceleration control of the vehicle during the coasting operation based on the input data in accordance with the presence or absence of the preceding vehicle. Automatic driving is performed.

Hereinafter, the results of the arithmetic processing performed by the coast control ECU 16f of this embodiment will be described in more detail with reference to FIGS. FIG. 7 plots the inter-vehicle distance change with the ON / OFF of the accelerator switch 16c and the ON / OFF of the brake switch 16d as a function of time, and FIG. 8 plots the change of the vehicle speed as a function of time. Things. In FIG. 7, in a section, the accelerator switch is ON and the brake switch is OFF. In this case, in the control flowchart of FIG.
Is determined to be NO, so that VB = 0 in S117, and the brake control by the control device 16 is not performed. Therefore, in this section, the inter-vehicle distance to the preceding vehicle gradually decreases due to acceleration traveling by the accelerator operation of the driver.

Next, in the section, both the accelerator switch and the brake switch are OFF, and therefore, in the control flowchart of FIG. 4, both S103 and S104 are determined to be YES, which means that the vehicle has started coasting. Then, the presence or absence of the preceding vehicle is determined in S108, and the following distance control in S112 is started.

That is, the headway time T ₀ = K · L ₀ / v ₀ with the preceding vehicle is calculated from the inter-vehicle distance L 0 with the preceding vehicle and the vehicle speed v 0 at point A in the figure, which is the start point of the section, and the following head Is controlled to be equal to or less than the target headway time (see the control flowchart of FIG. 5).

In the section, the accelerator switch remains OFF, but the brake switch is ON. Then, NO is determined in S104 of FIG.
At 118, the brake operation amount VB is set to 0.5 VB. Then, the brake operation amount V by the control device 16
The brake 22 operates and decelerates according to the magnitude relationship between B and the brake oil pressure by the driver's brake pedal operation,
The distance between the vehicle and the preceding vehicle gradually increases (see FIG. 2).
reference).

In the section, the accelerator switch is set to O
This shows a case where the brake switch is turned off again while the FF is maintained. In this case, the following distance control in S112 is performed again. That is, similar to the section,
The deceleration is controlled so as to be equal to or longer than the headway time determined by the inter-vehicle distance to the preceding vehicle and the vehicle speed at the point B in the drawing, which is the start point of the section.

Finally, in the section, as in the section, the driver operates the accelerator again to turn on the accelerator switch. In this case, the control by the control device 16 is released and the connection with the preceding vehicle is released. The inter-vehicle distance gradually decreases.

FIG. 8 shows the time change of the vehicle speed in the vehicle speed control mode when there is no preceding vehicle. In the section, the control is not performed by the control device 16 and the vehicle speed increases in accordance with the driver's accelerator operation. Will be

Next, in the section, both the accelerator switch and the brake switch are turned off, and the control device 16
Is started. That is, the brake operation amount VB is determined so as to be equal to or lower than the vehicle speed at the point A in the figure, which is the start point of the section, and the deceleration control is performed (see FIG. 6).

In the section, the accelerator switch is turned off.
F, the brake switch is turned ON by the driver's operation of the brake pedal, and the vehicle speed control mode by the control device 16 is released. However, as shown in S118 of FIG. 4, the brake operation amount VB is VB = 0. Since the brake operation amount is constantly maintained at a value other than 0 because the brake operation amount is gradually reduced by 5VB, the brake is operated by the higher brake oil pressure according to the magnitude comparison between the VB and the brake oil pressure according to the driver's brake pedal operation amount. It will work.

In the section, the accelerator switch is again
Since both the brake switches are turned off and the coasting is started, the control by the control device 16 is started again, and the deceleration control is performed so as to be equal to or lower than the vehicle speed in B in FIG.
reference).

In the section, the case where the driver operates the accelerator and the accelerator switch is turned on is shown. In this case, the control by the control device 16 is started, and the vehicle speed is increased according to the accelerator operation amount of the driver. Is performed.

As described above, the present embodiment is characterized in that control is performed automatically during coasting in which neither the accelerator nor the brake is operated by the driver (including the stopped state). When there is a vehicle, control is performed so that the preceding vehicle does not approach within the headway time at the start of coasting (vehicle distance control mode). If there is no preceding vehicle, the vehicle speed does not increase more than the vehicle speed at the start of coasting. (Vehicle speed control mode), and the acceleration side is left to the operation of the driver's intention, so that highly reliable automatic traveling can be performed.

[0060]

As described above, according to the vehicle traveling control device of the present invention, the automatic deceleration control during coasting is performed, so that the stability of the system is high and the danger of rear-end collision even in a general urban area can be obtained. Can be surely prevented, and automatic traveling can be performed that matches the driver's operational feeling .

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of one embodiment of a vehicle travel control device according to the present invention.

FIG. 2 is an explanatory diagram of an operation of a change valve in the embodiment.

FIG. 3 is a configuration block diagram of a control device in the embodiment.

FIG. 4 is a coast control ECU according to the embodiment.
It is a processing flowchart figure of.

FIG. 5 is a processing flowchart of a headway control mode in the embodiment.

FIG. 6 is a processing flowchart of a vehicle speed control mode in the embodiment.

FIG. 7 is an explanatory diagram showing a change in the inter-vehicle distance in the inter-vehicle control mode in the embodiment.

FIG. 8 is an explanatory diagram of a vehicle speed change in a vehicle speed control mode in the embodiment.

[Explanation of symbols]

 16 Control device 16a Inter-vehicle distance sensor 16b Vehicle speed sensor 16c Accelerator switch 16d Brake switch 16f Coast control ECU 22 Brake

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60K 31/00-31/18 B60K 41/00-41/28 B60T 7/12-7/22 B60T 8/32-8 / 96 F02D 29/00-29/06

Claims (1)

(57) [Claims] 1. A distance detecting means for detecting an inter-vehicle distance from a preceding vehicle, a vehicle speed detecting means for detecting a vehicle speed of the own vehicle, an operation detecting means for detecting the presence or absence of an accelerator operation and a brake operation, and the operation detecting means at a case where it is detected without the accelerator operation and brake operation, controlling the headway time at the time the accelerator operation and brake operation without at the operation detection means is detected when the preceding vehicle is present target
Control means for controlling the brake as a value, and controlling the brake using the vehicle speed at the time when the accelerator operation and no brake operation are detected by the operation detection means as a control target value when there is no preceding vehicle. A travel control device for a vehicle, comprising: