JPH11348599A - Traveling control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely effect the acceleration control and the deceleration control at an appropriate timing to meet the intention of a driver by determining the control mode according to the operated inter-vehicle distance deviation correlation value and the operated relative speed correlation value on a control mode map. SOLUTION: A mode transition map uniquely determines the control mode according to the coordinate position on the mode transition map by inputting the inter-vehicle distance error γ and the relative speed Vr. That is, the inter- vehicle distance deviation correlation value γ which is the inter-vehicle distance error or the relative speed correlation value Vr which is a relative speed is respectively shifted to the positive side of the point 0, and when it exceeds the accelerator- ON threshold, the control mode is judged to be the acceleration control mode. On the other hand, when the inter-vehicle distance deviation correlation value γ or the relative speed correlation value Vr is respectively shifted to the negative side of the point 0, and it exceeds the brake-ON threshold, the control mode is judged to the brake control mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device for a vehicle, and more particularly, to a tracking drive control technique in the drive control.

[0002]

2. Related Background Art In recent years, in order to reduce the driving operation of an automobile, a travel control device having an inter-vehicle distance control device for pursuing a preceding vehicle has been developed and put into practical use.

[0003] A traveling control device provided with this inter-vehicle distance control device detects an inter-vehicle distance between a host vehicle and a preceding vehicle based on information from a forward recognition device such as a camera or a laser radar. The engine output and the braking force are adjusted so that the distance becomes a preset target inter-vehicle distance, thereby accelerating and decelerating the vehicle to track the preceding vehicle (tracking control).

By the way, in such a traveling control device,
The timing at which the vehicle is accelerated or decelerated is an important factor in determining the riding comfort and the like. For example, Japanese Patent Application Laid-Open No. H8-132931 discloses that the start timing is appropriately set in the deceleration control. A proposal for a simple configuration is disclosed.

[0005]

However, in the proposal disclosed in the above publication, the invention is limited to deceleration control, and when the preceding vehicle and the host vehicle are both traveling at a constant speed during control, Prerequisites, such as only being applied, are imposed, making it less versatile and hard to be realistic. According to the proposal, when the own vehicle is approaching the preceding vehicle, the deceleration of the preceding vehicle is not considered.For example, when traveling in an urban area where acceleration and deceleration are high, the Is difficult to apply.

Further, regarding the parameters used as control criteria, the above proposal uses the correlation value of the relative speed between the own vehicle and the preceding vehicle and the correlation value of the present inter-vehicle distance as parameters. The term of the target inter-vehicle distance, which is the control target, does not exist in the parameters. That is, in a case where the target inter-vehicle distance is appropriately set and the traveling control is performed, the proposal cannot be applied as it is, which is not realistic.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a vehicle in which acceleration control and deceleration control can always be performed easily and reliably at appropriate timing according to the driver's intention. It is an object of the present invention to provide a travel control device.

[0008]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, the vehicle speed of the own vehicle is accelerated or decelerated so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes the target inter-vehicle distance. In the travel control device of the vehicle to be controlled, an inter-vehicle distance deviation correlation value that calculates an inter-vehicle distance deviation correlation value corresponding to a deviation between the inter-vehicle distance information from the inter-vehicle distance detection means and the target inter-vehicle distance set by the target inter-vehicle distance setting means. Calculating means for calculating a relative speed correlation value corresponding to the relative speed between the host vehicle and the preceding vehicle; and a control mode corresponding to the inter-vehicle distance deviation correlation value and the relative speed correlation value. The control mode map includes a control mode map which is divided into at least an acceleration control mode region and a deceleration control mode region, and is stored and held. Control mode in accordance with the inter-vehicle distance deviation correlation value and the calculated relative velocity correlation value is determined.

Therefore, in the tracking driving control, the acceleration control mode or the deceleration control mode is selected to perform the acceleration control or the deceleration control of the vehicle, respectively.
Each of these control modes can be easily performed at an appropriate timing according to the driver's intention based on the inter-vehicle distance deviation correlation value and the relative speed correlation value that are the most appropriate as the parameters of the tracking driving control, equivalent to the criteria for the driving operation of the driver. In addition, the determination is reliably made, the stability and reliability of the tracking drive control are improved, and the vehicle can be driven with a comfortable ride without a sense of discomfort.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a schematic configuration diagram of a traveling control device according to the present invention mounted on a vehicle 1. Hereinafter, the traveling control device according to the present invention will be described with reference to FIG. The configuration will be described.

At the front of the vehicle 1, a laser beam is emitted toward the front, and by scanning this laser beam, an object located in front of the vehicle 1 can be recognized, and the distance to the object can be measured. A simple scanning laser radar 2 is provided. In addition, the vehicle 1
A CCD camera 4 for capturing an image in front of is mounted. The CCD camera 4 is also capable of recognizing an object located in front, a lane (white line), and the like.

A throttle valve 8 is connected to the engine 6 for controlling the amount of intake air to the engine 6 and adjusting the engine output. More specifically, the throttle valve 8 can automatically adjust the valve opening based on an operation signal output from an electronic control unit (ECU) 50 to be described later according to the opening of an accelerator pedal (not shown) or the like. A simple throttle actuator 12 is provided.

A pair of left and right front wheels (drive wheels) 20, 20 and a pair of right and left rear wheels (sub wheels) 22, 22 are provided with service brakes 24 such as hydraulic disc brakes, respectively. It is connected to a brake pedal 28 via a brake master cylinder 26 having a pressure booster. Further, the brake master cylinder 26 is provided with a negative pressure type brake actuator 30 capable of automatically operating the service brake 24 in response to an operation signal from the ECU 50 regardless of an input from the brake pedal 28.

A wheel speed sensor 32 for detecting a right wheel speed VSR and a left wheel speed VSL is provided in the vicinity of the rear wheels 22, 22, which are slave wheels, corresponding to each wheel.
These wheel speed sensors 32 function as host vehicle speed detecting means for detecting the host vehicle speed Ve.

On a steering column 36 of a steering wheel 34 provided in the cabin of the vehicle 1, a tracking travel switching operation switch 38 for switching a travel control device of the vehicle 1 between a normal traveling state and a traveling state by tracking traveling control is provided. Is provided. When the tracking travel changeover operation switch 38 is operated to the set side, the inter-vehicle distance control, that is, the tracking travel control is started, and when it is operated to the reset side, the inter-vehicle distance control is released.

The ECU 50 is a main control unit that controls various controls of the vehicle 1. As shown in the figure, the input side of the ECU 50 is connected to various sensors and switches such as the scanning laser radar 2, the CCD camera 4, the wheel speed sensors 32, 32, and the tracking drive switch 38. ,
Various driving devices such as a throttle actuator 12 and a brake actuator 30 are connected to the output side.

Hereinafter, the control contents of the traveling control device thus configured will be described. That is, the operation and effect according to the present invention will be described.

Referring to FIG. 2, there is shown a flowchart of a tracking drive control routine. Hereinafter, a control procedure of the tracking drive control according to the present invention will be described with reference to FIG.

When the tracking travel changeover switch 38 is operated to the set side to start the tracking travel control, first, in step S10, a process of determining the preceding vehicle is performed. Specifically, in step S10, when an object is recognized in front of the vehicle 1 based on information from the scanning laser radar 2 and the CCD camera 4, it is determined whether or not the object is a vehicle. If it is determined that the vehicle is a vehicle, the vehicle is determined to be a preceding vehicle. When there are a plurality of preceding vehicles, for example, a vehicle located on the own vehicle lane recognized by the CCD camera 4 or on the own vehicle lane estimated from the own vehicle steering wheel angle is determined as the preceding vehicle. As a result, the preceding vehicle is determined, and, for example, the preceding vehicle, that is, the preceding vehicle when the tracking drive switching switch 38 is set, is fixed as the preceding vehicle of the vehicle 1.

In step S12, the wheel speed sensor 3
The vehicle speed of the vehicle 1, that is, the own vehicle speed Ve, is calculated based on the information from the control units 2 and 32. Here, the vehicle speed Ve is, for example,
It is calculated from (1).

Ve = (VSR + VSL) / 2 (1) That is, the own vehicle speed Ve is an average value of the right wheel speed VSR and the left wheel speed VSL.

In step S14, the distance from the host vehicle to the preceding vehicle, that is, the inter-vehicle distance L is accurately measured based on the information from the scanning laser radar 2 (inter-vehicle distance detecting means).

In the next step S16, the relative speed Vr between the host vehicle and the preceding vehicle is calculated based on the inter-vehicle distance information L. More specifically, the relative speed Vr is calculated based on the value of the inter-vehicle distance information L when the routine was last executed, that is, the amount of change ΔL between the previous value and the current value. At this time, if the change amount ΔL is positive and the relative speed Vr is positive, it is considered that the own vehicle is moving away from the preceding vehicle. If the change amount ΔL is negative and the relative speed Vr is negative, the own vehicle approaches the preceding vehicle. Can be considered to be.

In step S18, the preceding vehicle speed Vf is calculated from the following equation (2) based on the host vehicle speed Ve and the relative speed Vr.

Vf = Ve + Vr (2) Here, the preceding vehicle acceleration αf is also calculated by differentiating the preceding vehicle speed Vf. Specifically, the preceding vehicle acceleration αf is calculated from the change amount ΔVf between the previous value and the current value of the preceding vehicle speed information Vf when the routine was last executed.

In the next step S20, the host vehicle speed Ve is determined.
The target inter-vehicle distance Le is set based on the following formula (target inter-vehicle distance setting means). More specifically, a map (not shown) indicating the relationship between Ve and Le is previously set and stored in the ECU 50 through experiments or the like, and the target inter-vehicle distance Le is obtained from the map.

Then, in the next step S22, the control mode is determined. More specifically, FIG.
A mode transition map (control mode map) as shown in FIG. 1 is set and stored in advance by experiments and the like.
The control mode is selected and determined based on the mode transition map (control mode determining means). Hereinafter, the mode transition map according to the present invention will be described.

The mode transition map has a horizontal axis representing an inter-vehicle distance error γ (%) and a vertical axis representing a relative speed Vr (km / h).
Based on r, the control mode is divided into an accelerator control area, a brake control area, and a coasting area in advance by experiments and the like. Here, both the inter-vehicle distance error γ and the relative speed Vr are the most suitable parameters as the parameters of the tracking driving control by making the same as the criterion of the driving operation of the driver, and the inter-vehicle distance error γ is the target inter-vehicle distance L
The following equation (3) is calculated so as to take e into consideration (inter-vehicle distance deviation correlation value calculation means), and the relative speed Vr is set to the value described above (relative speed correlation value calculation means).

Γ = (L−Le) · 100 / Le (3) By the way, the inter-vehicle distance error γ increases or decreases to the positive (+) side or the negative (−) side across the value 0 due to the fluctuation of the inter-vehicle distance L. Also, the relative speed Vr also increases or decreases to a positive (+) side or a negative (-) side with a value of 0 as a boundary depending on the traveling state of the preceding vehicle and the own vehicle.

Therefore, in the mode transition map, the point O where the inter-vehicle distance error γ is 0 and the relative speed Vr is 0
(0, 0), that is, the target point of the tracking drive control is located at the center of the map. That is, in the map, the current inter-vehicle distance L is equal to the target inter-vehicle distance Le.
When the own vehicle speed Ve matches the preceding vehicle speed Vf and the own vehicle follows the preceding vehicle without any speed difference, the coordinate point between the inter-vehicle distance error γ and the relative speed Vr It is designed to be stably located in the center.

In the mode transition map, when the inter-vehicle distance error γ and the relative speed Vr are input, the control mode is uniquely determined by the coordinate position on the mode transition map. For example, if the inter-vehicle distance error γ or the relative speed Vr has shifted to the positive (+) side from the point O (0, 0), and exceeds the accelerator ON threshold line, the control mode is the accelerator control mode. (Acceleration control mode), while the inter-vehicle distance error γ or the relative speed Vr has shifted to the negative (−) side from the point O (0, 0), and has exceeded the brake ON threshold line. In this case, the control mode is determined to be the brake control mode (deceleration control mode).

That is, by using the mode transition map according to the present invention, based on the inter-vehicle distance error γ and the relative speed Vr which are equivalent to the criteria for the driving operation of the driver and are suitable as the parameters of the tracking driving control, Therefore, the control mode is easily and reliably determined at an appropriate timing according to the intention.

After the control mode is selected and determined by the mode transition map, the process proceeds to step S24.

In step S24, it is determined whether or not the control mode is the accelerator control mode. If the result of the determination is true (Yes) and the accelerator control mode is determined, the process proceeds to step S26.

In step S26, throttle control is performed.

When the control mode is the accelerator control mode, that is, it can be determined that the inter-vehicle distance L is large and the relative speed Vr increases to the positive side, and the own vehicle moves away from the preceding vehicle. , The vehicle 1 is preferably accelerated. Therefore, in the step S26, the throttle control is performed so that the inter-vehicle distance error γ and the relative speed Vr are directed to the point O (0, 0), that is, the target point of the tracking drive control, and thereby the vehicle 1 is accelerated. .

The throttle control is for controlling the operation of the throttle actuator 12 to accelerate the vehicle 1 according to the running state of the vehicle 1. As a result, the vehicle 1 is controlled to be accelerated. Note that the throttle control is actually executed by a separately provided subroutine, but details thereof are omitted here.

On the other hand, if the determination result of step S24 is false (N
In o), if the control mode is not the accelerator control mode, the process proceeds to step S28, and it is determined whether the control mode is the brake control mode. If the result of the determination is true (Yes) and the brake control mode is determined, the process proceeds to step S30.

In step S30, braking control is performed.

When the control mode is the brake control mode, on the contrary, it can be judged that the following distance L is small, the relative speed Vr is negative, and the own vehicle is approaching the preceding vehicle. In such a case, the vehicle 1 should be decelerated. Therefore, in step S30, the braking control is performed so that the inter-vehicle distance error γ and the relative speed Vr are directed to the point O (0, 0), that is, the target point of the tracking control, and the vehicle 1 is decelerated. .

The braking control is for controlling the operation of the brake actuator 30 to decelerate the vehicle 1 according to the running state of the vehicle 1. As a result, the vehicle 1 is decelerated. Note that the braking control is actually executed by a separately provided subroutine, but details thereof are omitted here.

If the decision result in the step S28 is false (No),
That is, if the control mode is neither the accelerator control mode nor the brake control mode, that is, if the control mode is the coasting control mode, the process proceeds to step S32 to perform the coasting control.

When the control mode is in the coasting control mode, as apparent from the mode transition map, one of the inter-vehicle distance error γ and the relative speed Vr is on the positive (+) side and the other is on the other side. This is the case where the value is on the negative (-) side, or the case where both are on the same sign side and both values are small. That is, when the control mode is the coasting control mode, a situation where the inter-vehicle distance L is large but the relative speed Vr is negative and the own vehicle is gradually approaching the preceding vehicle, or a case where the inter-vehicle distance L is small but the relative speed is small Vr is positive and it can be determined that the vehicle is gradually moving away from the preceding vehicle. In such a case, the inter-vehicle distance error γ and the relative speed Vr gradually increase without accelerating or decelerating the vehicle 1. Point O
It is thought to go to (0,0). Therefore, in step S32, coasting control is performed to cause the vehicle 1 to run by inertia.

More specifically, in the coasting control, neither the throttle control nor the braking control is performed, the throttle actuator 12 is maintained in a constant state, and the throttle opening is maintained at a constant opening.

By the way, once the throttle control or the braking control is performed, the vehicle 1 then accelerates or decelerates, whereby the inter-vehicle distance error γ and the relative speed Vr change favorably toward the value 0. In other words, the control mode changes from the accelerator control mode or the brake control mode to the coasting control mode. In the present embodiment, hysteresis is provided on the mode transition map as indicated by diagonal lines. .

That is, when transiting from the coasting control mode to the accelerator control mode or the brake control mode,
The control mode is switched to each control mode when the accelerator ON threshold line (solid line) or the brake ON threshold line (solid line) is exceeded. Conversely, when transitioning from the accelerator control mode or the brake control mode to the coasting control mode, Accel O
It is set so that the mode is not switched to the coasting control mode unless the threshold value of the FF (dashed-dotted line) or the threshold line of brake OFF (dashed-dotted line) is exceeded.

As a result, when the control mode is switched, the switching is preferably prevented from being repeated frequently, so that the control is stabilized, and the tracking drive control with high reliability and good riding comfort is achieved. Feasible.

As described above, in the traveling control device according to the present invention, the distance is set according to the inter-vehicle distance error γ and the relative speed Vr which are the most suitable as the parameters of the tracking traveling control by making the same as the criterion of the driving operation of the driver. Based on the mode transition map, for example, the accelerator control mode is selected when both the inter-vehicle distance error γ and the relative speed Vr are large on the positive (+) side, and when both are on the negative (-) side, the brake control is performed. The mode is selected.

Therefore, according to the traveling control device of the present invention, the acceleration and deceleration of the vehicle 1 are determined very easily and reliably at an appropriate timing according to the driver's intention. It can be implemented.

The accelerator O in the mode transition map
The threshold lines N and OFF and the brake lines ON and OFF are not limited to the positions shown in FIG. 3 and can be tuned based on the type of vehicle and the like. For example,
Regarding the width of the hysteresis between the accelerator ON and OFF and between the brake ON and OFF, control accuracy can be improved by narrowing the width, and conversely, comfortable control can be realized by widening the hysteresis. It becomes possible.

In the above embodiment, each threshold line is a straight line. However, if a good result is obtained, these threshold lines may be constituted by a curve.

[0052]

As described above in detail, according to the vehicle running control apparatus of the first aspect, the vehicle speed of the own vehicle is controlled so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes the target inter-vehicle distance. The vehicle travel control device includes a control mode map in which a control mode area is divided into at least an acceleration control mode area and a deceleration control mode area according to an inter-vehicle distance deviation correlation value and a relative speed correlation value. A control mode is determined according to the calculated inter-vehicle distance deviation correlation value and the calculated relative speed correlation value using a control mode map.

Therefore, in the tracking driving control, the acceleration control mode or the deceleration control mode is selected to perform the acceleration control or the deceleration control of the vehicle. These control modes are used as criteria for determining the driving operation of the driver. Equivalently, it can be easily and reliably determined at an appropriate timing according to the driver's intention based on the inter-vehicle distance deviation correlation value and the relative speed correlation value most suitable as the parameters of the tracking cruise control, and the tracking cruise control is stable. Thus, it is possible to improve the performance and reliability, and to realize a comfortable running of the vehicle without any discomfort.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a travel control device mounted on a vehicle.

FIG. 2 is a flowchart showing a tracking drive control routine.

FIG. 3 is a diagram showing a mode transition map (control mode map) according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle (own vehicle) 2 Scanning laser radar 32 Wheel speed sensor 50 Electronic control unit (ECU)

Claims (1)

[Claims] An inter-vehicle distance detecting means for detecting the inter-vehicle distance, wherein the inter-vehicle distance control means detects the inter-vehicle distance so that the inter-vehicle distance between the own vehicle and a preceding vehicle becomes a target inter-vehicle distance. Target inter-vehicle distance setting means for setting a target inter-vehicle distance; and an inter-vehicle distance deviation correlation value corresponding to a deviation between the inter-vehicle distance information from the inter-vehicle distance detection means and a target inter-vehicle distance set by the target inter-vehicle distance setting means. An inter-vehicle distance deviation correlation value calculating means, a relative speed correlation value calculating means for calculating a relative speed correlation value according to a relative speed between the own vehicle and the preceding vehicle, the inter-vehicle distance deviation correlation value and the relative speed correlation value The control mode area is divided into at least an acceleration control mode area and a deceleration control mode area in accordance with the control mode area, and a control mode map stored and held is calculated by the inter-vehicle distance deviation correlation value calculating means. Control mode determination means for determining a control mode from the control mode map in accordance with the obtained inter-vehicle distance deviation correlation value and the relative speed correlation value calculated by the relative speed correlation value calculation means. Control device of the vehicle to be driven.