JPH11105579A - Headway control device - Google Patents

Abstract

(57) Abstract: The present invention relates to an inter-vehicle control device that executes inter-vehicle control of a vehicle such that an inter-vehicle distance to a preceding vehicle matches a target inter-vehicle distance. It is an object of the present invention to prevent frequent occurrence of an inter-vehicle distance shorter than the distance. SOLUTION: When an ACC switch is in an ON state, ACC control for accelerating and decelerating the vehicle is executed such that an inter-vehicle distance X with a preceding vehicle coincides with a target inter-vehicle distance X ^* . A
The inter-vehicle distance X secured with the preceding vehicle during the non-execution of the CC control is stored as the normal inter-vehicle distance Xd of the driver. AC
During execution of the C control, the target inter-vehicle distance X ^* is added by adding a predetermined value Xa to the normal inter-vehicle distance Xd according to the traveling environment of the vehicle ^.
Is calculated (steps 192 to 220).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle control device, and more particularly to an inter-vehicle control device that executes inter-vehicle control so that the inter-vehicle distance from a preceding vehicle coincides with a target inter-vehicle distance.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 60-1313
As disclosed in Japanese Patent No. 27, there is known a device that executes headway control for accelerating and decelerating a vehicle such that the headway distance between the vehicle and a preceding vehicle coincides with a target headway distance. According to the above-described conventional device, for example, when the vehicle travels on a highway at a substantially constant speed, the vehicle can follow the preceding vehicle without performing any accelerator operation or brake operation on the vehicle.

[0003]

When the above-mentioned inter-vehicle control is executed for the purpose of assisting the driver in accelerating or decelerating, for example, when the preceding vehicle suddenly decelerates, the inter-vehicle distance is set to a target value. It is desirable that there is room to be shorter than the inter-vehicle distance. If such room is left, it is possible to obtain an appropriate assisting effect for the acceleration / deceleration operation during the steady running, and to entrust the driver to perform the sudden braking in an emergency.

[0004] However, if there is room for the inter-vehicle distance to be shorter than the target inter-vehicle distance, the inter-vehicle distance between the preceding vehicle and the inter-vehicle distance secured by the inter-vehicle control is reduced by the driver under normal conditions. It may be shorter than the distance (hereinafter, usually referred to as inter-vehicle distance). When the inter-vehicle distance from the preceding vehicle is shorter than the normal inter-vehicle distance, the driver attempts to perform a brake operation. For this reason, if the inter-vehicle distance to the preceding vehicle frequently becomes shorter than the normal inter-vehicle distance during the inter-vehicle control, the deceleration operation cannot be effectively assisted by the inter-vehicle control.

Therefore, in order to effectively assist the deceleration operation in a system that allows the inter-vehicle distance to be shorter than the target inter-vehicle distance, the inter-vehicle distance to the preceding vehicle frequently increases during the inter-vehicle control. Usually, it is necessary to determine the target inter-vehicle distance so as not to be shorter than the inter-vehicle distance. The present invention has been made in view of the above points, and provides a headway control device capable of effectively assisting a deceleration operation by setting a target headway distance for headway control based on a normal headway distance. Aim.

[0006]

The above object is achieved by the present invention.
In the headway control device for executing the headway control for accelerating and decelerating the vehicle such that the headway distance with the preceding vehicle matches the target headway distance, the headway is secured between the preceding vehicle while the headway control is not executed. A vehicle-to-vehicle control comprising: a normal vehicle-to-vehicle storage unit that stores a calculated vehicle-to-vehicle distance as a normal vehicle-to-vehicle distance; and a target vehicle-to-vehicle distance calculation unit that calculates the target vehicle-to-vehicle distance by adding a predetermined value to the normal vehicle-to-vehicle distance. Achieved by the device.

[0007] In the present invention, the normal inter-vehicle distance is the inter-vehicle distance secured by the driver under normal conditions. The target inter-vehicle distance is calculated by adding a predetermined value to the normal inter-vehicle distance. Therefore, even if the inter-vehicle distance with the preceding vehicle is reduced as compared with the target inter-vehicle distance during the inter-vehicle control, the inter-vehicle distance does not frequently become shorter than the normal inter-vehicle distance. In this case, the deceleration operation is effectively assisted by the following distance control.

[0008] The object of the present invention is as described in claim 2.
2. The inter-vehicle control device according to claim 1, wherein the normal inter-vehicle storage unit stores a plurality of normal inter-vehicle distances corresponding to a driving environment, and the target inter-vehicle distance calculation unit includes, among the plurality of normal inter-vehicle distances, This is achieved by an inter-vehicle control device that calculates the target inter-vehicle distance based on a normal inter-vehicle distance according to a driving environment during the inter-vehicle control.

In the present invention, the inter-vehicle distance normally secured by the driver while the inter-vehicle control is not performed varies depending on the driving environment of the vehicle. The inter-vehicle control device of the present invention stores a plurality of normal inter-vehicle distances corresponding to the driving environment of the vehicle while the inter-vehicle control is not performed. Further, the inter-vehicle control device of the present invention selects a value corresponding to the driving environment of the vehicle from the plurality of stored values during execution of the inter-vehicle control, and sets a target inter-vehicle distance based on the selected value. According to the above-described processing, it is possible to effectively prevent the inter-vehicle distance from frequently becoming shorter than the normal inter-vehicle distance during the execution of the inter-vehicle control, regardless of a change in the driving environment of the vehicle.

In the present invention, the driving environment of the vehicle includes the type of the traveling road (general road, highway, etc.), the time zone (day, night, etc.), the weather, the behavior of the vehicle (straight, turning, etc.). , Driver arousal state, vehicle loading state, travel road curvature, driver's viewpoint height (eye point height),
And the type of vehicle (passenger car, one-box car, pickup truck car, etc.) and the like.

[0011] The above object is as described in claim 3.
The distance control apparatus according to claim 1, wherein the distance control apparatus includes a predetermined value calculation unit that calculates the predetermined value according to a driving environment during the control of the distance between vehicles. In the present invention, the actual normal inter-vehicle distance varies according to the driving environment of the vehicle. The headway control device of the present invention sets a predetermined value to be added to the stored value of the normal headway distance when calculating the target headway distance according to the driving environment of the vehicle. According to the above processing, even if the actual normal inter-vehicle distance changes due to a change in the driving environment, the inter-vehicle distance with the preceding vehicle frequently increases during the inter-vehicle control compared to the actual normal inter-vehicle distance. It won't be short.

In the present invention, the driving environment of the vehicle includes the type of the traveling road (general road, highway, etc.), the time zone (day, night, etc.), the weather, and the behavior of the vehicle (straight, turning, etc.). , Driver arousal state, vehicle loading state, travel road curvature, driver's viewpoint height (eye point height),
And the type of vehicle (passenger car, one-box car, pickup truck car, etc.) and the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system configuration diagram of a headway control device according to an embodiment of the present invention. The headway control device according to the present embodiment is controlled by an electronic control unit 10 (hereinafter, referred to as ECU 10). The headway control device includes a brake pedal 12. In the vicinity of the brake pedal 12,
A brake switch 14 is provided. The brake switch 14 outputs an ON signal when the brake pedal 12 is depressed. The output signal of the brake switch 14 is supplied to the ECU 10. The ECU 10 determines whether or not the brake pedal 12 is depressed based on the output signal of the brake switch 14.

The brake pedal 12 is connected to a brake booster 16. The high pressure passage 18, the low pressure passage 20, and the control hydraulic pressure passage 22 communicate with the brake booster 16. The low pressure passage 20 communicates with the reservoir tank 24. On the other hand, the accumulator 2
Along with 6, a pump 30 communicates via a check valve 28. The pump 30 pumps up the brake fluid in the reservoir tank 24 so that a predetermined accumulator pressure P _ACC is stored in the accumulator 26, and
To pump.

A regulator chamber is formed inside the brake booster 16. When the brake pedal 12 is depressed, the brake booster 16 selectively connects the high-pressure passage 18 and the low-pressure passage 20 to the regulator chamber. A control hydraulic pressure passage 22 is always in communication with the regulator chamber. Therefore, the control fluid pressure passage 22, the regulator pressure P _RE corresponding to the brake pedal force is derived.

A master cylinder 32 is fixed to the brake booster 16. The master cylinder 32, a brake pedal force Fp which is input to the brake pedal 12, and the assist force Fa corresponding to the regulator pressure P _RE is transmitted. Therefore, when the brake pedal 12 is depressed, the resultant force Fp + Fa having a predetermined boosting ratio with respect to the brake depression force Fp is transmitted to the master cylinder 32.

A first hydraulic chamber 34 and a second hydraulic chamber 36 are formed inside the master cylinder 32. A master cylinder pressure P _{M / C} corresponding to the resultant force Fp + Fa is generated in the first hydraulic chamber 34 and the second hydraulic chamber 36. The first hydraulic chamber 34 and the second hydraulic chamber 36 are respectively provided with hydraulic passages 38,
It communicates with a P valve 42 through 40. Hydraulic passage 4
The master pressure sensor 43 communicates with 0. The master pressure sensor 43 outputs an electric signal pMC corresponding to the master cylinder pressure PM _{/ C.} The ECU 10 outputs the output signal pMC
, The master cylinder pressure P _{M / C} is detected.

A first hydraulic passage 44 communicating with the first hydraulic chamber 34 and a second hydraulic passage 46 communicating with the second hydraulic chamber 36 communicate with the P valve 42. The P valve 42 supplies the master cylinder pressure P _{M / C} to the first hydraulic pressure passage 44 as it is, and connects the master cylinder pressure P _{M / C} to the second hydraulic pressure passage 46 in a region where the master cylinder pressure P _{M / C} exceeds a predetermined value. Pressure P
Supply the liquid pressure with _{M / C} reduced at a predetermined ratio.

The headway control device of the present embodiment includes a regulator switching solenoid 48 (hereinafter referred to as STR 48). The high-pressure passage 18 and the control hydraulic passage 22 described above communicate with the STR 48, and the third hydraulic passage 50 communicates with the STR 48. The STR 48 realizes a state (OFF state) in which the control hydraulic pressure passage 22 and the third hydraulic pressure passage 50 are electrically connected to each other in a normal state, and receives a drive signal from the ECU 10 so that the high-pressure passage 18 and the third hydraulic pressure passage This is a two-position solenoid valve that realizes a state (on state) that conducts with the solenoid valve 50.

In the first hydraulic passage 44, a first assist solenoid 52 (hereinafter referred to as SA- ₁ 52) and a second assist solenoid 52 are provided.
The assist solenoid 54 (hereinafter, referred to as SA- ₂ 54) is in communication. In addition, the communication passages 56 and 58 and the pipes 60 and 62 are provided in the SA- ₁ 52 and the SA- ₂ 54, respectively.
Are in communication. The pipes 60 and 62 communicate with a wheel cylinder 64 of the right front wheel FR and a wheel cylinder 66 of the left front wheel FL. SA _-1 52 and SA _-2 54 are
A state where the first hydraulic passage 44 and the wheel cylinders 64 and 66 are electrically connected (off state) is realized in a normal state, and a drive signal is supplied from the ECU 10 to connect the communication paths 56 and 58 to the wheel cylinders 64 and 66. This is a two-position solenoid valve that realizes a conductive state (ON state).

The communication passage 56 includes a holding valve 68 and a check valve 7.
In addition, it communicates with the third hydraulic pressure passage 50 through the pressure reducing valve 72 and with the reservoir passage 74 through the pressure reducing valve 72. Similarly, the communication passage 58 communicates with the third hydraulic passage 50 via the holding valve 76 and the check valve 78, and the pressure reducing valve 8.
0 and communicate with the reservoir passage 74. The reservoir passage 74 communicates with the reservoir tank 24 described above.

The holding valves 68 and 76 are two-position solenoid valves that are kept open in a normal state and are closed when a drive signal is supplied from the ECU 10. Check valve 70, 7
A one-way valve 8 permits only the flow of the fluid from the communication passages 56 and 58 to the third hydraulic passage 50. Also,
The pressure reducing valves 72 and 80 maintain the valve closed state in a normal state,
This is a two-position solenoid valve that is opened when a drive signal is supplied from the solenoid valve 10.

A third assist solenoid 82 (hereinafter referred to as SA- ₃ 82) communicates with the second hydraulic passage 46. Further, the third hydraulic passage 50 and the rear wheel passage 84 communicate with the SA- ₃ 82. SA- ₃ 82 is normally second
A state where the hydraulic passage 46 and the rear wheel passage 84 are conducted (off state) is realized, and a drive signal is supplied from the ECU 10 to conduct the third hydraulic passage 50 and the rear wheel passage 84 (on). (State) is a two-position solenoid valve.

A communication passage 90 communicates with the rear wheel passage 84 via a holding valve 86 and a check valve 88, and a communication passage 96 communicates with the rear wheel passage 84 via a holding valve 92 and a check valve 94. The holding valves 86 and 92 maintain the valve open state in the normal state, and
This is a two-position solenoid valve that is closed when a drive signal is supplied from U10. The check valves 88 and 94 are one-way valves that allow only the flow of the fluid from the communication passages 90 and 96 to the rear wheel passage 84.

A reservoir passage 74 communicates with the communication passage 90 via a pressure reducing valve 98 and a wheel cylinder 102 of the right rear wheel RR communicates via a pipe 100. Similarly, the communication passage 96 communicates with the reservoir passage 74 via the pressure reducing valve 104, and communicates with the wheel cylinder 108 of the left rear wheel RL via the pipe 106. The inter-vehicle control device includes wheel speed sensors 110 to 116 corresponding to the respective wheels.
It has. Each of the wheel speed sensors 110 to 116 generates a pulse signal at a cycle corresponding to the wheel speed Vw of each wheel. The ECU 10 detects the wheel speed Vw of each wheel based on the pulse signals and calculates the vehicle speed SPD based on the wheel speed Vw.

The output signal of the radar 118 is supplied to the ECU 10. The radar 118 is a vehicle traveling ahead of the vehicle, that is, a preceding vehicle traveling on its own lane and a vehicle traveling on an adjacent lane (hereinafter, referred to as an adjacent vehicle).
An output signal is generated in accordance with the relative distance and relative speed with respect to. The ECU 10 detects a relative distance and a relative speed between the preceding vehicle and the adjacent vehicle based on the output signal.

The output signal of the front and rear G sensor 120 is supplied to the ECU 10. The longitudinal G sensor 120 is a longitudinal acceleration G (hereinafter, referred to as longitudinal G) generated in the vehicle.
And outputs an electric signal corresponding to. The ECU 10 detects the front and rear G based on the output signal. The ECU 10 has A
The CC switch 122 and the ACC display panel 124 are connected. The ACC switch 122 allows the driver
A switch that is turned on when requesting execution of C (Adaptive Cruise Control) control. On the other hand, the ACC display panel 124 is a panel for notifying the driver whether or not the ACC control is being performed. The ECU 10
When it is detected that the C switch 122 is turned on, the ACC control described later is executed, and the ACC panel 124 is driven to display the execution to the driver.

A clock 126, a temperature sensor 128, and a wakefulness sensor 130 are connected to the ECU 10. The ECU 10 recognizes the time based on the output signal of the clock 126 and recognizes the temperature of the environment surrounding the vehicle based on the output signal of the temperature sensor 128. Further, E
The CU 10 detects a driver's arousal state based on an output signal of the arousal degree sensor 130. The arousal level sensor 130
Detects the awake state of the driver based on, for example, the movement of the driver's eyeball, the frequency of corrective steering, the driver's heart rate, and the like.

The ECU 10 includes a navigation device 13
2 are connected. The navigation device 132 supplies the location of the vehicle to the ECU 10 together with the map information.
The ECU 10 detects the type (road, expressway, etc.) of the road on which the vehicle is traveling, the curvature of the road, and the like based on the data. The ECU 10 includes an electronically controlled automatic transmission 12.
4 (hereinafter, referred to as AT124). AT
The gear 124 can be shifted down by a manual operation and can be shifted down according to a command from the ECU 10.

A throttle actuator 136 and a throttle position sensor 138 are connected to the ECU 10. The ECU 10 can make the throttle opening coincide with an arbitrary target opening by performing feedback control of the throttle actuator 136 based on the output signal of the throttle position sensor 138. The wiper switch 140 is connected to the ECU 10. ECU1
A value of 0 determines whether snowfall or rainfall has occurred, depending on whether the wiper switch 140 is on.

The ECU 10 also includes a vehicle height sensor 142
Is connected. The vehicle height sensor 142 issues an output signal according to the vehicle height of the vehicle. In the present embodiment, the height of the vehicle indicates a change according to the load of the vehicle. Therefore, the output signal of the vehicle height sensor 142 corresponds to the load of the vehicle. The ECU 10 detects the load amount of the vehicle based on the output signal of the vehicle height sensor 142.

Next, the operation of the headway distance control device according to the present embodiment will be described. When the ACC control is requested by the driver of the vehicle,
ACC when the ACC switch 122 is turned on
Execute control. The ACC control is based on the following distance X to the preceding vehicle.
Is a control for accelerating and decelerating the vehicle so as to maintain the vehicle distance near the target inter-vehicle distance X ^* . According to the ACC control, when the inter-vehicle distance X from the preceding vehicle is shorter than the target inter-vehicle distance X ^* , control for decelerating the vehicle (hereinafter, referred to as braking control) is executed. When X is longer than target inter-vehicle distance X ^* , control for accelerating the vehicle (hereinafter, referred to as acceleration control) is executed.

According to the system configuration shown in FIG.
Acceleration control can be realized by turning off all the electromagnetic valves incorporated in the hydraulic circuit during the execution of the control and performing feedback control of the throttle actuator 136 so that the throttle opening increases. That is,
In the system configuration shown in FIG. 1, when all the solenoid valves incorporated in the hydraulic circuit are turned off, the state shown in FIG. 1 (hereinafter, referred to as a normal state) is realized in the headway control device. According to the normal state, the wheel cylinders 64 and 66 of the left and right front wheels communicate with the first hydraulic chamber 34 of the master cylinder 32 via SA- ₁ 52 and SA- ₂ 54. On the other hand, the wheel cylinders 102, 108 of the left and right rear wheels are provided with holding valves 86,
It communicates with the second hydraulic chamber 36 of the master cylinder 32 via 92 and SA- ₃ 82.

The ACC control is executed under the condition that the depression of the brake pedal 12 is released. Therefore, A
During the execution of the CC control, the master cylinder pressure PM _{/ C} is released to the atmospheric pressure. Therefore, when the normal state is realized during the execution of the ACC control, the wheel cylinder pressures P _{W / C} of all the wheels are adjusted to substantially the atmospheric pressure. Under the situation where the wheel cylinder pressure P _{W / C} is adjusted to the atmospheric pressure, no braking force is generated on each wheel. When the throttle opening is increased in such a situation, the vehicle accelerates smoothly. Therefore, according to the headway distance control device of the present embodiment, as described above, the acceleration control is realized by turning off all the solenoid valves and driving the throttle actuator 136 so as to increase the throttle opening. be able to.

According to the system configuration shown in FIG.
The deceleration control can be realized by turning on the 48, SA- ₁ 52, SA- ₂ 54 and SA- ₃ 82, and fully closing the throttle valve during execution of the ACC control. Hereinafter, in the system configuration shown in FIG.
The state realized by turning on the switches 48, SA- ₁ 52, SA- ₂ 54 and SA- ₃ 82 is referred to as an automatic braking state.

According to the automatic braking state, the third hydraulic passage 50
To the accumulator pressure P _ACC . In this case, even if the brake pedal 12 is not depressed, a high brake fluid pressure is generated in the third fluid pressure passage 50. According to the automatic braking state, the wheel cylinders 64 of the left and right front wheels,
66 is disconnected from the first hydraulic pressure passage 44 and the communication passages 56 and 5 are closed.
8 can be conducted. Therefore, according to the automatic braking state, the wheel cylinder pressure P _{W / C} of the left and right front wheels can be increased using the accumulator pressure P _ACC as a hydraulic pressure source.

When the throttle valve is fully closed in such a situation, the vehicle smoothly decelerates. Therefore, according to the headway distance control device of the present embodiment, as described above, STR4
8, the deceleration control can be realized by turning on the SA- ₁ 52, SA- ₂ 54 and SA- ₃ 82 and fully closing the throttle valve. FIG. 2 shows a flowchart of an example of a control routine executed by the ECU 10 to implement the above-described deceleration control. The routine shown in FIG. 2 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 2 is started, first, the processing of step 150 is executed.

In step 150, the ACC switch 12
It is determined whether or not 2 is on. As a result, A
If it is determined that the CC switch 122 is not on, the current routine is terminated without any further processing. On the other hand, when it is determined that the ACC switch 122 is on, the process of step 152 is executed next.

In step 152, the following distance X to the preceding vehicle is measured based on the output signal of the radar 118. In step 154, the target inter-vehicle distance X ^* is read.
This is a value that is set as the target value of the following distance X during execution of the ACC control. The target inter-vehicle distance X ^* is a predetermined value X which is set to the inter-vehicle distance Xd normally secured by the driver (hereinafter, referred to as the normal inter-vehicle distance Xd).
It is calculated by adding a. Note that the target inter-vehicle distance X
The calculation method of ^* will be described later in detail.

In step 156, it is determined whether or not the following distance X is smaller than the target following distance Xd. As a result, when it is determined that Xt0 <X ^* is not established, it can be determined that an appropriate inter-vehicle distance is secured with the preceding vehicle. In this case, the current routine is terminated without any further processing. On the other hand, when it is determined that Xt0 <X ^* is satisfied, it can be determined that an appropriate inter-vehicle distance with the preceding vehicle is not secured. In this case, the process of step 158 is executed next.

In step 158, the above-described pressure reduction control is executed. When the process of step 158 is executed,
A braking force is generated on each wheel, and an appropriate deceleration can be generated in the vehicle. When the process of step 158 is completed, the current routine ends. According to the above processing, the vehicle can be quickly decelerated after the inter-vehicle distance X with the preceding vehicle becomes shorter than the target inter-vehicle distance Xd. The ACC control is usually performed in a situation where a large relative speed does not occur between the preceding vehicle and the host vehicle. For this reason, when the vehicle is decelerated by the above-described processing, thereafter, the following distance X
Starts to extend toward the target inter-vehicle distance X ^* . Therefore,
According to the above processing, the inter-vehicle distance X can be maintained near the target inter-vehicle distance X ^* during the execution of the ACC control.

FIG. 3 shows the target inter-vehicle distance X from the preceding vehicle 160.
^The state where the vehicle 162 is running at a position separated by ^* is shown. Xd shown in FIG. 3 is the normal inter-vehicle distance Xd of the driver of the vehicle 162. The driver of the vehicle 162 is the preceding vehicle 1
When the inter-vehicle distance X with respect to the vehicle 60 becomes shorter than the normal inter-vehicle distance Xd, an attempt is made to perform a braking operation. Therefore, in order to effectively substitute the deceleration operation of the driver by the ACC control and to enhance the convenience of the ACC control, during the execution of the ACC control, the inter-vehicle distance X shorter than the normal inter-vehicle distance Xd is frequently changed. It is necessary that it does not occur.

In this embodiment, the target inter-vehicle distance X ^* is
As described above, the calculation is performed by adding the predetermined value Xa to the normal inter-vehicle distance Xd. The predetermined value Xa is the above-mentioned maximum value of the relative speed RV generated between the preceding vehicle 160 and the vehicle 162 when the preceding vehicle 160 is in a steady running state and the vehicle 162 is under the ACC control. This is the distance required to be eliminated by deceleration control. The inter-vehicle distance control apparatus according to the present embodiment has a first feature in that the target inter-vehicle distance X ^* is set to a value obtained by adding the above-described predetermined value Xa to the normal inter-vehicle distance Xd.

The normal inter-vehicle distance Xd of the driver is
For example, it changes depending on whether the running road is a general road or a highway. Further, the distance Xa required to eliminate the relative speed RV with the preceding vehicle 160 expands and contracts, for example, when the loading state of the vehicle 162 changes. Therefore, in order to always ensure excellent convenience irrespective of the traveling environment of the vehicle, it is desirable that the normal inter-vehicle distance Xd and the predetermined value Xa are appropriately set according to the traveling environment of the vehicle.

The inter-vehicle distance control device of this embodiment stores a plurality of normal inter-vehicle distances Xd according to the driving environment, and selects and uses the optimum normal inter-vehicle distance Xd from the plurality of stored values during execution of the ACC control. Has a second feature. Further, the headway distance control device according to the present embodiment has a third characteristic in that an appropriate predetermined value Xa is calculated according to the traveling environment during execution of the ACC control. Hereinafter, the first to third features described above will be described in detail with reference to FIGS. 4 to 7.

FIG. 4 shows a flowchart of a control routine executed by the ECU 10 to learn a plurality of normal inter-vehicle distances Xd according to the traveling environment. The routine shown in FIG. 4 is a routine that is repeatedly started each time the processing is completed. When the routine shown in FIG. 4 is started, first, the process of step 170 is executed. In step 170, it is determined whether or not the ACC switch 122 is off. As a result, if it is determined that the ACC switch 122 is not in the OFF state, the current routine is terminated without any further processing. Meanwhile, ACC
If the switch 122 is determined to be in the off state,
Next, the process of step 172 is performed. According to the above processing, the execution of step 172 and subsequent steps is permitted only during the non-execution of the ACC control.

In step 172, initialization is performed. In step 172, specifically, a process of resetting the repetition number n to “0” is executed. In step 174, the vehicle speed SPD, time, state of the wiper switch 140, air temperature, and navigation information are read. The ECU 10 determines whether the current time zone is daytime or nighttime based on the time, and determines whether it is raining or snowing based on the state of the wiper switch 140. Then, the ECU 10
Rainfall and snowfall are distinguished on the basis of the temperature, and the type of travel road (general road or highway) and curvature are detected based on the navigation information. The ECU 10 recognizes the traveling environment of the vehicle by executing the above processing.

In step 176, the inter-vehicle distance X to the preceding vehicle is measured, and the measured value is stored as the inter-vehicle distance Xt0 corresponding to the repetition number "0". In step 178, the inter-vehicle distance Xt0 stored as described above is stored.
Is determined to satisfy X _MIN ≦ Xt0 ≦ X _MAX . When the driver of the vehicle follows the preceding vehicle and travels, the inter-vehicle distance X is made equal to the normal inter-vehicle distance Xd.
The acceleration / deceleration operation is performed so that the inter-vehicle distance X falls within an appropriate range. X _MIN and X _MAX used in this step 178
Are predetermined constants that respectively define the lower and upper limits of the appropriate range.

Therefore, in step 178, X _MIN ≤X
If it is determined that t0 ≦ X _MAX is not established, it can be determined that the vehicle is not running following the preceding vehicle. In this case, after step 178, step 17 is performed again.
2 is executed. On the other hand, at step 178, X
If it is determined that _MIN ≦ Xt0 ≦ X _MAX is satisfied, the vehicle is running following the preceding vehicle, that is, the driver performs an acceleration / deceleration operation to match the following distance X to the normal following distance Xd. Can be determined to be. In this case, the process of step 180 is executed following step 178.

At step 180, the repetition number n is incremented. In step 182, the inter-vehicle distance X to the preceding vehicle is measured, and the measured value is stored as the inter-vehicle distance Xtn corresponding to the repetition number n. In step 184, a deviation ΔX = | Xtn−Xt0 | between the inter-vehicle distance Xt0 corresponding to the repetition number “0” and the inter-vehicle distance Xtn corresponding to the repetition number n is calculated.

In step 186, the above step 184
It is determined whether or not the deviation ΔX calculated in is smaller than the predetermined value X ₀ . As a result, if it is determined that ΔX <X ₀ does not hold, the inter-vehicle distance X for the repetition number n is determined.
It can be determined that a large variation is recognized between tn and the inter-vehicle distance Xt0 for the repetition number “0”. When the inter-vehicle distance X greatly fluctuates, the inter-vehicle distance X is likely to be a value greatly deviating from the normal inter-vehicle distance Xd. Therefore, the inter-vehicle distance X measured in such a situation should not be used as basic data for updating the normal inter-vehicle distance Xd. Therefore, if it is determined in step 186 that ΔX <X ₀ does not hold, the processes in and after step 172 are executed again. On the other hand, if it is determined in step 186 that ΔX <X ₀ holds, it can be determined that the following distance X is stable and is maintained near the normal following distance Xd. In this case, the process of step 188 is executed after step 186.

In step 188, whether the repeating number n has reached the predetermined value n ₀ is determined. as a result,
If it is determined that n ≧ n ₀ does not hold, the processing of step 180 and thereafter is executed again. Step 18
In the condition of No. 8, the condition of the step 184 is continuously n ₀
It is established by establishing it twice. Therefore, this step 1
If it is determined at 88 that n ≧ n ₀ holds, it can be determined that the inter-vehicle distance X has been stabilized in a very small range while the repetition number n is incremented from “0” to n ₀ .

When the inter-vehicle distance X is stable as described above
Is a value that the inter-vehicle distance X approximates the normal inter-vehicle distance Xd.
It can be determined that there is. Therefore, in step 188, n
≧ n ₀If it is determined that
“0” to n₀Distance Xti (i = 1 to n) corresponding to₀)
Can be determined to be close to the normal inter-vehicle distance Xd. Up
If such a determination is made in step 188,
The process of step 190 is executed.

At step 190, the repetition number "0"
, The normal inter-vehicle distance Xd _*** corresponding to the current traveling environment is updated. Figure 5 shows the EC
4 shows a map of a normal inter-vehicle distance Xd stored in U10.
The ECU 10 specifies the current traveling environment with the following five items based on the data read in step 174.

(I) Road type (general road or highway) (ii) Time zone (day or night) (iii) Weather (sunny, rainy or snowy) (iv) Vehicle behavior (straight or turning) (V) The vehicle speed SPD ECU 10 specifies the current driving environment prior to the process of step 190, and specifies the normal inter-vehicle distance Xd corresponding to the driving environment in the map shown in FIG. For example,
The running path is a general road, the time zone is daytime, the weather is sunny, the vehicle is traveling straight, and the vehicle speed SPD is 8
In the case of 5 km / h, Xd ₈₅₁ is the normal inter-vehicle distance Xd _***
Specified as

The ECU 10 then proceeds to step 19
0, the normal inter-vehicle distance Xd _*** and the repetition number “0”
Average value of the distance between the vehicle and Xt0 (Xd _*** + Xt0) /
2 is set as a new normal inter-vehicle distance Xd _*** . As described above, the inter-vehicle distance Xt0 is a value approximating the normal inter-vehicle distance Xd at that time. Therefore, according to the processing of step 190, the normal inter-vehicle distance Xd _*** for the current traveling environment can be appropriately updated.
When the process of step 190 ends, the current routine ends.

FIG. 6 shows E to calculate the target inter-vehicle distance X ^*.
3 shows a flowchart of an example of a control routine executed by the CU 10. The routine shown in FIG. 6 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 6 is started, first, the process of step 192 is executed. In step 192, it is determined whether or not the ACC switch 122 is on. As a result, if it is determined that the ACC switch 122 is not on, the current routine is terminated without any further processing. On the other hand, when it is determined that the ACC switch 122 is on, the process of step 194 is performed.

At step 194, the vehicle speed SPD, time,
The state, temperature, and navigation information of the wiper switch 140 are read. The ECU 10 performs the above-described processing based on the data read in step 194.
The driving environment of the vehicle is specified by the items (i) to (V). In step 196, the normal inter-vehicle distance Xd is calculated. In step 196, specifically, the value stored as the normal inter-vehicle distance Xd _*** corresponding to the traveling environment specified in step 194 in the map shown in FIG. Is set as

At step 198, a predetermined value Xa is calculated. FIG. 7 shows an ECU for calculating the predetermined value Xa.
10 shows a flowchart of a subroutine executed by the subroutine 10.
The routine shown in FIG. 7 is started each time the execution of step 198 is requested. When the routine shown in FIG. 7 is started, first, the process of step 200 is executed.

In step 200, the awake state of the driver is detected. The headway control device according to the present embodiment is a device that entrusts the driver with the execution of sudden braking. When the driver is in a non-awakening state, a long delay is likely to occur after a situation in which sudden braking is requested occurs until the sudden braking operation is actually performed. Therefore, when it is recognized that the driver is in the non-awakening state during the execution of the ACC control, it is preferable to secure a longer target inter-vehicle distance X ^* .

In step 202, a first correction coefficient α is calculated. The first correction coefficient α is a correction coefficient for reflecting the awake state of the driver on the target inter-vehicle distance X ^* . In the present step 202, the first correction coefficient α is set to a larger value as the awakening degree of the driver is higher or lower. Step 20
At 4, the amount of loading of the vehicle is detected. In order to eliminate the relative speed RV between the two when the vehicle is approaching the preceding vehicle, it is necessary to execute the deceleration control for a longer time as the loaded amount of the vehicle increases. Therefore, in the present embodiment, the larger the load capacity of the vehicle, the larger the predetermined value Xa
It is appropriate to secure a long time.

In step 206, the corner R of the road on which the vehicle is traveling is detected. The driver of the vehicle has a running corner R
The smaller is, the easier it is to lose track of the preceding car. It is appropriate to secure a long inter-vehicle distance X in a situation where the driver easily loses sight of the preceding vehicle. Therefore, in this embodiment, the corner R
It is appropriate to secure the predetermined value Xa longer as the length X becomes longer.

By the way, depending on the ability of the radar 118, the smaller the corner R, the more likely the radar 118 misses the preceding vehicle. In such a situation, in order to reduce the frequency with which the radar 118 loses sight of the preceding vehicle, it is appropriate to reduce the inter-vehicle distance X as the corner R becomes smaller.
Therefore, in the headway control device of the present embodiment, the radar 11
In the case where priority is given to the catching ability of the vehicle 8, it is effective to reduce the inter-vehicle distance X as the corner R becomes smaller.

At step 208, the number of vehicles traveling on the adjacent lane is detected. When a large number of vehicles are present in the adjacent lane, it is necessary to consider the possibility that some of those vehicles may change lanes in the own lane. When a vehicle traveling in an adjacent lane changes lanes between the own vehicle and the preceding vehicle, the inter-vehicle distance X between the preceding vehicle (lane changing vehicle) and the own vehicle may be sharply reduced. Therefore, in the headway control device of the present embodiment, it is appropriate to secure a longer headway distance X as the number of vehicles running in the adjacent lane increases.

In step 210, the driver's eye point height (line of sight) is read. The ECU 10 stores an eye point height corresponding to the vehicle. In step 210, specifically, a process of reading out the stored value is executed. The driver of the vehicle perceives a change in the inter-vehicle distance X more sensitively as the eye point is higher. Therefore, it is appropriate that the target inter-vehicle distance X ^* to be ensured during the execution of the ACC control is set shorter as the eye point is higher.

In step 212, the type of the vehicle is read. The ECU 10 stores the type of vehicle (one box, passenger car, pickup truck, etc.) on which the headway control device of the present embodiment is mounted. In a vehicle such as a one-box vehicle in which the driver is seated near the front end of the vehicle, a change in the inter-vehicle distance X is more easily sensed than in a vehicle having a hood. As described above, the recognizability of the change in the inter-vehicle distance X changes depending on the type of the vehicle. Therefore, the target inter-vehicle distance X ^* to be ensured during the execution of the ACC control ^.
It is appropriate that the vehicle is set to be shorter as the vehicle is more sensitive to the change in the inter-vehicle distance X.

In step 214, a second correction coefficient β is calculated. The second correction coefficient β is a correction coefficient for reflecting the influence of the various factors described above on the predetermined value Xa. In the present embodiment, the second correction coefficient β is larger as the load capacity of the vehicle is larger, larger as the corner R of the traveling road is smaller, and larger as more vehicles are present on the adjacent lane, and the eye point height is higher. The lower the setting, the larger the setting, and the larger the type of the vehicle, the harder it is to detect the change in the inter-vehicle distance X.

In step 216, step 196 is executed.
Is read, that is, the normal inter-vehicle distance Xd corresponding to the current traveling environment is read. In step 218, a predetermined value Xa is calculated according to the following equation. Note that “k” shown in the following equation is a constant. Xa = k + α · Xd + β (1) When the process of step 218 ends, the current routine ends. According to the above equation (1), the predetermined value Xa can be set to a larger value as the inter-vehicle distance Xd is longer, and the predetermined value Xa can be appropriately expanded or contracted according to various situations. It should be noted that the constant k, the first correction coefficient α and the second correction coefficient β are such that the predetermined value Xa eliminates the maximum relative speed RV generated between the preceding vehicle during steady running and the vehicle under ACC control. Is set to be the necessary distance.

When the routine shown in FIG. 7 is completed, the process of step 220 shown in FIG. 6 is executed. In step 220, the target inter-vehicle distance X ^* is calculated by substituting the normal inter-vehicle distance Xd calculated in step 196 and the predetermined value Xa calculated in step 198 into the following equation.

X ^* = Xd + Xa (2) When the process of step 220 ends, the current routine ends. According to the above equation (2), the distance Xa required to eliminate the relative speed RV with the preceding vehicle under the current traveling environment is added to the normal inter-vehicle distance Xd according to the current traveling environment.
Can be set as the target inter-vehicle distance X ^* .
According to the target inter-vehicle distance X ^* , the inter-vehicle distance X between the preceding vehicle and the host vehicle becomes shorter than the target inter-vehicle distance X ^* during the execution of the ACC control as long as the preceding vehicle continues the steady running. There is no. For this reason, according to the headway control device of the present embodiment, it is possible to effectively perform the deceleration operation of the driver, and to realize excellent convenience.

In the above embodiment, the ACC control corresponds to the "inter-vehicle control" of the first aspect, and the ECU 10 executes the processing of steps 170 to 190 to execute the ACC control. 1 and said claim 2
The “normal inter-vehicle storage means” described in Steps 192 to 192
"Target inter-vehicle distance calculating means" according to claim 1 or 2, by executing the processing of 198 and 200.
Have been realized respectively. Further, in the above embodiment, the "predetermined value calculating means" according to claim 3 is realized by the ECU 10 executing the processing of steps 200 to 218.

By the way, in the above embodiment, FIG.
Normal inter-vehicle distance Xd stored in the map shown in FIG._***To AC
Although learning is performed during non-execution of C control, the present invention
Is not limited to this, and the map shown in FIG.
The standard inter-vehicle distance Xd which is a reference in advance _***And remember that
It may be used without updating the value.

[0073]

As described above, according to the first aspect of the present invention, it is possible to prevent the inter-vehicle distance from the preceding vehicle from being frequently shortened as compared with the normal inter-vehicle distance during the inter-vehicle control. . Therefore, according to the present invention, the deceleration operation can be effectively assisted by the following distance control.

According to the second and third aspects of the present invention, when the driving environment of the vehicle changes, the target inter-vehicle distance is appropriately set as compared with the actual normal inter-vehicle distance for the driving environment. Can be set to a long value. Therefore, according to the present invention, the deceleration operation can always be effectively assisted by the inter-vehicle control regardless of a change in the driving environment of the vehicle.

[Brief description of the drawings]

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

FIG. 2 is a flowchart of a control routine executed to implement deceleration control in the following distance control apparatus of the present embodiment.

FIG. 3 is a diagram illustrating a state in which the vehicle is traveling at a position separated from a preceding vehicle by a target inter-vehicle distance X ^* .

FIG. 4 is a flowchart of a control routine executed to learn a normal inter-vehicle distance Xd _*** corresponding to a traveling environment in the inter-vehicle control device of the present embodiment.

FIG. 5 is an example of a map in which a normal inter-vehicle distance Xd _*** corresponding to a traveling environment is stored in the inter-vehicle control device of the embodiment.

FIG. 6 is a flowchart of a control routine that is executed by the headway control device of the present embodiment to calculate a target headway distance X ^* .

FIG. 7 is a flowchart of a control routine executed to calculate a predetermined value Xa in the following distance control apparatus of the present embodiment.

[Explanation of symbols]

Reference Signs List 10 Electronic control unit (ECU) 16 Brake booster 32 Master cylinder 118 Radar 122 ACC switch 126 Clock 128 Temperature sensor 130 Arousal level sensor 132 Navigation device 140 Wiper switch 142 Vehicle height sensor 160 Vehicle ahead 162 Vehicle X Inter-vehicle distance X ^* Target inter-vehicle distance Xd Normal inter-vehicle distance Xd _*** Normal inter-vehicle distance corresponding to driving environment Xa Predetermined value

Claims (3)

[Claims] An inter-vehicle control device for executing inter-vehicle control for accelerating or decelerating a vehicle such that an inter-vehicle distance with a preceding vehicle coincides with a target inter-vehicle distance. Normal inter-vehicle storage means for storing the inter-vehicle distance to be performed as a normal inter-vehicle distance of the driver, and target inter-vehicle distance calculating means for calculating the target inter-vehicle distance by adding a predetermined value to the normal inter-vehicle distance. Characteristic inter-vehicle control device. 2. The inter-vehicle control device according to claim 1, wherein the normal inter-vehicle storage means stores a plurality of normal inter-vehicle distances corresponding to a driving environment, and the target inter-vehicle distance calculation means includes a plurality of the normal inter-vehicle distances. An inter-vehicle distance control device that calculates the target inter-vehicle distance based on a normal inter-vehicle distance according to a driving environment during the inter-vehicle control. 3. The headway distance control device according to claim 1, further comprising a predetermined value calculating means for calculating the predetermined value according to a driving environment at the time of the headway distance control.