JP2000043705A - Automatic deceleration control device combination vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic deceleration control device for a combination vehicle which can restrain the generation of a jackknife phenomenon at time of automatic deceleration and display the deceleration effect efficiently. SOLUTION: Automatic braking force is generated to the wheels of a tractor and trailer so that the car speed at the turning time and a lateral acceleration are not exceeded a prescribed allowable value and a vehicle is automatically decelerated by an automatic deceleration control device. During this automatic deceleration, the steer tendency of a vehicle is calculated (step S12) and when it is judged that the tendency is shifted to an over steer tendency (step S14), the brake of the tractor wheel is stopped (step S16). Thereby, the pushing-up from the trailer is removed and the generation of a jackknife phenomenon is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic deceleration control device for a connected vehicle for automatically lowering a vehicle speed when turning.

[0002]

2. Related Background Art An example of this kind of automatic deceleration control device is a turning behavior control device disclosed in Japanese Patent Application Laid-Open No. 3-42360. This known turning behavior control device obtains a tire grip limit vehicle speed according to a turning steering amount, and when the vehicle speed detected during turning exceeds the limit vehicle speed, automatically applies a brake to reduce the vehicle speed.

[0003]

In an articulated vehicle in which a trailer is towed by a tractor, there is a jackknife phenomenon as an unstable behavior peculiar to the articulated vehicle. When the braking force of the tractor wheel is larger than that of the wheel, the braking force is generated due to the pushing force (so-called thrust) from the trailer. In order to prevent such a jackknife phenomenon, it is generally known that a braking force of a trailer wheel is set to be larger than that of a tractor wheel.

However, when the set braking force of the normal trailer wheel is set larger than that of the tractor wheel, the wheel lock easily occurs when the trailer is empty,
A sufficient deceleration effect cannot be obtained. On the other hand, when the vehicle is empty, the braking force exerted by the trailer wheels is reduced. Therefore, in order to obtain a sufficient deceleration effect, the braking force on the tractor wheels must be increased as much as possible. However, if the braking force of the tractor wheel is set to a large value as described above, the jackknife phenomenon may be caused at the time of braking. Therefore, in the case of a connected vehicle, the braking force balance between the tractor wheel and the trailer wheel cannot be constantly fixed, and the deceleration effect can be appropriately obtained by simply applying a known turning behavior control technology. I can't.

The present invention has been made in view of the above circumstances, and has as its object to achieve a sufficient deceleration effect by automatic deceleration without destabilizing the behavior of the vehicle at the time of turning. An object of the present invention is to provide an automatic deceleration control device for a connected vehicle.

[0006]

The above object has been achieved by the present invention. According to a first aspect of the present invention, there is provided an automatic deceleration control device for a connected vehicle, comprising: And independent control means for operating independently of the braking operation by the driver, and control means for controlling the operation of the independent control means. The independent braking means is capable of generating a braking force on the tractor wheel and the trailer wheel by its operation, and is provided such that the braking force can be adjusted. The control means evaluates information of the detection signal obtained from the traveling state detecting means, and operates the independent braking means to limit at least one of the vehicle speed and the vehicle lateral acceleration during turning to a predetermined allowable value or less based on the evaluation result. To generate an automatic braking force on the tractor wheel and the trailer wheel to automatically decelerate the vehicle. And
The control means further reduces the automatic braking force of the tractor wheels when the vehicle steer tendency shifts to the oversteer tendency as a result of further evaluating the detection signal from the traveling state detection means during execution of the automatic deceleration. I have.

According to the automatic deceleration control device of the first aspect, the automatic deceleration is performed based on the evaluation result of the traveling state information, and the vehicle speed or the vehicle lateral acceleration at the time of turning is limited to an allowable value or less. During the execution of such automatic deceleration, when the vehicle shifts to the oversteer tendency, the automatic braking force of the tractor wheel is reduced, so that the tractor does not receive the boosting force from the trailer.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic deceleration control device will be described below with reference to the drawings.

Referring to FIG. 1, a tractor 1 of a connected vehicle
Is equipped with an air brake system that uses air tanks 2, 4, and 6 as operating pressure sources. The brake system includes front and rear service brake paths 8, 10, a service brake path 12 for a trailer, and an independent brake path 14, 1
6,18.

More specifically, the front service brake path 8 extracts the air pressure of the air tank 2 through the brake valve 20 and supplies the air pressure to the front brake path 24 through the double check valve 22. The rear service brake path 10 is connected to the relay valve 2
The air pressure of the air tank 4 is taken out through 6 and the air pressure is supplied to the rear brake path 30 via the double check valve 28. The relay valve 26 receives a signal pressure from the brake valve 20 through a pilot pressure path 32.

[0011] Also, a trailer service brake path 1
2 is an air tank 6 through a dual relay valve 34.
Is supplied to the brake hose 38 via the double check valve 36. The brake hose 38 is connected to a brake coupling of a trailer (not shown). The relay valve 34 receives a signal pressure from the brake valve 20 via the pilot pressure paths 40 and 42.

On the other hand, each of the independent brake paths 14 takes out the air pressure of the air tank 2 through the air supply valve 44 and supplies the air pressure to the front brake path 24 via the double check valve 22. Each of the independent brake paths 16 extracts the air pressure of the air tank 4 through the air supply valve 46 and supplies the air pressure to the rear brake path 30 via the double check valve 28.

The independent brake path 18 is connected to the air supply valve 4.
The air pressure of the air tank 6 is taken out through 8, and the air pressure is supplied to the brake hose 38 via the double check valve 36. The above-described air supply valves 44, 46, 4
Each of the reference numerals 8 comprises a solenoid on-off valve.

The above-described front brake path 24 and rear brake path 30 are connected to the brake chamber 50, respectively.
The front and rear brake paths 24, 30 are respectively connected to the pressure control valves 5 as shown in FIG.
2, 54 are interposed. A pressure control valve 56 is also interposed between the outlet port of the double check valve 36 and the brake hose 38. Each of the pressure control valves 52, 54 and 56 is formed of a solenoid switching valve, and each of the pressure control valves 52, 54 and 56 has a normal position for ventilating the inserted path,
The position between an operation position where the downstream pressure connected to the brake chamber 50 is released to the atmosphere and an operation position where the supply air pressure from each of the air tanks 2, 4, and 6 is shut off and the pressure in the brake chamber 50 is maintained. Can be switched.

The tractor 1 has respective air supply valves 44, 46, 48
And an electronic control unit (ECU) 58 for controlling the operation of each pressure control valve 52, 54, 56,
Individual air supply valves 44, 46, 48 and pressure control valves 52, 5
The ECUs 4 and 56 are electrically connected to the ECU 58.

The independent brake path 14, including the above-described air supply valves 44, 46, 48 and pressure control valves 52, 54, 56,
Reference numerals 16 and 18 denote independent braking means that operates independently of the driver's braking operation, that is, depression of a brake pedal, operation of a trailer brake, and the like.
Is controlled by With the operation, the magnitude of the braking force generated on the tractor wheels (FR, FL, RR, RL) can be adjusted by adjusting the brake air pressure for each wheel of the tractor 1, and Also, the braking force of the trailer wheel can be adjusted separately from the tractor wheel.

The tractor 1 is equipped with a plurality of sensors as means for detecting its running state and outputting a signal. Specifically, a steering angle sensor 60, a wheel speed sensor 62, a yaw rate sensor 64 , Longitudinal acceleration sensor 6
6 and a lateral acceleration sensor 68 are provided.

In the above-described air brake system, each brake chamber 50 is provided with a brake air pressure sensor 70 for detecting a brake air pressure. In addition,
The brake valve 20 is provided with a depressed air pressure sensor 72 for detecting an outlet air pressure corresponding to the depressed amount of the brake pedal, and the pressure control valve 56 is provided with a trailer-side brake path (not shown). (Not shown) is provided with a trailer air pressure sensor 74 for detecting the outlet air pressure to be supplied toward the outlet. The relay valve 26 (with LSV) is provided with an air pressure sensor 76 for detecting the outlet air pressure.

Referring to FIG. 2, there is shown a block diagram showing an electrical connection state for the ECU 58 to control the operation of the air brake system of the tractor 1. As illustrated, each of the various sensors described above is electrically connected to the ECU 58, and outputs a detection signal to the ECU 58.

The ECU 58 can process the sensor signals from these various sensors to obtain the traveling state information of the vehicle. For example, it is information such as the front wheel steering angle δ, the vehicle speed V, the actual yaw rate γ of the tractor 1, the longitudinal acceleration Gx, and the lateral acceleration Gy. The ECU 58 has a function of evaluating the information on the traveling state and controlling the operation of the air brake system based on the evaluation result.

Specifically, when the vehicle turns, information such as the vehicle speed V and the lateral acceleration Gy is evaluated, and a known automatic deceleration control is performed so that the vehicle speed V and the lateral acceleration Gy do not exceed predetermined allowable values. A braking force is automatically generated based on the law to prevent the vehicle from drifting out, spinning, and rolling over.
At this time, the ECU 58 determines the actual vehicle speed V when the vehicle turns.
Then, a deceleration required to limit the lateral acceleration Gy to a value equal to or less than the allowable value is obtained, and when the obtained deceleration exceeds a predetermined threshold, the automatic deceleration control is executed. Note that the ECU 58
An allowable value of the vehicle speed V, that is, a safe vehicle speed is obtained in accordance with the estimated turning radius and the road surface friction coefficient, and a predetermined allowable value of the lateral acceleration Gy is stored.

When the automatic deceleration control is started, the ECU 58
The target brake air pressure required to generate the required deceleration described above is calculated, and the air supply valve 4 is operated in accordance with the target air pressure.
4, 46, 48 and the pressure control valves 52, 54, 56 are operated and controlled, respectively. Specifically, each air supply valve 44, 46, 4
8 to the open position to switch the independent brake paths 14, 16,
18 while supplying air pressure to the individual pressure control valves 52,
The operation of the brakes 54 and 56 is controlled so that the actual brake air pressure matches the target pressure. The pressure control valves 52, 54, 56
Can be precisely controlled by switching the position periodically.

As described above, independent of the braking operation of the driver
As a result, the brake air pressure is supplied as shown in FIG.
Automatic braking on tractor wheels and trailer wheels
Force B ₁, B_TwoOccurs. At this time, for example, the trailer is empty
If the vehicle is in a car state, the braking force that can be actually exerted is
It is less than in the state.

[0024] Therefore, when the automatic deceleration control in this situation takes place, in fact the automatic braking force B ₁ and B _2, towards the braking force B ₁ of the tractor wheels is considered to increase. In this case, the tractor 1 receives the pushing force P from the trailer at its coupler position C due to the difference between the braking forces B ₁ and B ₂ . The pushing force P generates a turning yaw moment M that causes the tractor 1 to be cut inside the turning circle, based on the relationship between the coupler position C and the center of gravity g of the tractor 1. This turning yaw moment M is determined by the tractor 1
In the direction of oversteer. The inventors of the present invention pay attention to the influence of the pushing force P from the trailer generated at the time of automatic deceleration on the steer tendency of the tractor 1, and from the change tendency of the steer tendency,
It has been confirmed that the occurrence of the jackknife phenomenon can be predicted. The inventors have developed a logic for stabilizing a vehicle that is automatically decelerating by changing the balance between the automatic braking forces B ₁ and B ₂ according to the change in the behavior of the vehicle accompanying the change in the steering tendency. Invented.

FIG. 4 is a graph showing, as an example, a change in the steer tendency observed during execution of the automatic deceleration control. In the drawing, the vertical axis indicates the magnitude of the degree of understeer and the degree of oversteer in the vertical direction, respectively.

FIG. 5 is a flowchart of a braking force control routine executed by the ECU 58. Hereinafter, a procedure of the braking force control performed during execution of the automatic deceleration according to the flow charts of FIGS. Will be described.

As shown in FIG. 5, in step S10, the ECU 58 determines whether or not the automatic deceleration control is being executed. If the result is true (Yes), the process proceeds to step S12. Therefore, after the automatic deceleration control is started in the ECU 58, the procedure after step S12 is executed.

In step S12, the steering tendency of the vehicle,
That is, the degree of under or oversteer is calculated. This calculation can be performed by processing signals such as the front wheel steering angle δ, the vehicle speed V, and the actual yaw rate γ. Specifically, a deviation from the actual yaw rate is obtained based on the yaw rate derived from the reference model, and the degree of under or oversteer is calculated from the magnitude and sign of the deviation.

In step S14, it is determined whether the calculated steer tendency has shifted from understeer to oversteer. This determination can be made, for example, using the following method.

The ECU 58 stores the degree of understeer calculated so far as the time elapses.
From time t _{1, the} rate of change is negative,
Get a peak value of US ₁ of understeer degree at this time t _1. Then, a time t ₁ after, when the calculated understeering degree is equal to or less than one-half of the peak value US ₁ (time t _2), and that steering tendency of the tractor 1 is shifted to oversteer from understeer judgment I do.

As another determination method, for example, at time t ₃
Time t ₁ after, understeer degree as shown in the 0
When it falls to an oversteer tendency area, it can be determined that the steer tendency has shifted from under to oversteer tendency.

When the determination in step S14 is true by any one of the above-described determination methods, the process proceeds to the next step S16.

In step S16, braking of the tractor wheels is performed.
To stop. That is, the ECU 58 is provided with the air supply valves 44 and 46.
To the closed position to cut off the air pressure supply.
The control valves 52 and 54 are switched to the exhaust operation position to
Automatic braking force B generated on the wheels ₁Get rid of. This step
When the step S16 is executed, the automatic braking is performed as shown in FIG.
Force B_TwoWill automatically decelerate, and the tractor 1 will
At the coupler position C, the pull-back force D from the trailer
You. As a result, a pushing force P as shown in FIG. 3 is generated.
The vehicle's behavior is stabilized and automatic deceleration is performed.
The occurrence of the jackknife phenomenon during running is suppressed.

In this step S16, braking of the tractor wheel is not simply stopped, but the braking force B _1.
May be reduced. In this case, ECU 58 by operating the control of the pressure control valve 52, to reduce the automatic braking force B ₁ as appropriate to reduce the braking air pressure.

According to the automatic deceleration control device of the above-described embodiment, during vehicle turning, automatic deceleration control is performed to limit the vehicle speed or the lateral acceleration to an allowable value or less, and the automatic braking force B ₁ , since generating a B _2, it can be decelerated efficiently coupling the vehicle by utilizing these braking force effectively. Also, steering tendency during such deceleration control when it is determined that the process moves to oversteer tendency, since the automatic braking force B ₁ of a tractor wheel reduces (including termination of braking), the trailer By removing the boosting force P, the occurrence of the jackknife phenomenon can be suppressed. If the braking of the tractor wheels is stopped as in this embodiment, the vehicle can be quickly stabilized by immediately removing the pushing force P from the trailer.

In this embodiment, there are two methods for determining the shift to the oversteer tendency.
The two methods may be combined or used appropriately. Further, the determination method can be variously changed, and is not particularly limited. Further, the degree of understeer and degree of oversteer can be calculated not only from the detected actual yaw rate γ but also from other traveling state information.

In addition, it goes without saying that the specific structures of the air brake system and the sensors in FIG. 1 can be variously changed.

[0038]

As described above, according to the automatic deceleration control device for a connected vehicle according to the first aspect, the braking force balance between the tractor wheel and the trailer wheel is appropriately changed in accordance with the vehicle's tendency to steer. Thus, the vehicle can be automatically decelerated effectively while suppressing the occurrence of the jackknife phenomenon, and the stability can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a tractor equipped with a braking control device according to one embodiment.

FIG. 2 is a block diagram showing a control concept of the braking control device of FIG. 1;

FIG. 3 is a diagram illustrating a state when an automatic braking force is applied to each wheel in accordance with execution of automatic deceleration control.

FIG. 4 is a graph showing a time change of a steering tendency of a vehicle.

FIG. 5 is a flowchart showing a braking force control routine.

FIG. 6 is a diagram showing a state when braking of the tractor is stopped from the state of FIG. 4;

[Explanation of symbols]

 1 Tractor 14, 16, 18 Independent brake path (independent braking means) 44, 46, 48 Air supply valve (independent braking means) 52, 54, 56 Pressure control valve (independent braking means) 58 ECU (control means) 60 Steering angle Sensor (running state detecting means) 62 Wheel speed sensor (running state detecting means) 64 Yaw rate sensor (running state detecting means) 66 Longitudinal acceleration sensor (running state detecting means) 68 Lateral acceleration sensor (running state detecting means)

Claims (1)

[Claims] 1. A connected vehicle having a tractor and a trailer connected and towed to the tractor, a running state detecting means for detecting a running state of the vehicle and outputting a detection signal, and a braking operation by a driver Independent operating means for generating braking force on the tractor wheel and the trailer wheel, respectively, and independently controlling the braking force of the tractor wheel and the trailer wheel; and The output signal is evaluated, and based on the evaluation result, the operation of the independent braking means is controlled to limit at least one of the vehicle speed and the vehicle lateral acceleration at the time of turning to a predetermined allowable value or less. Control means for automatically decelerating the vehicle by generating an automatic braking force on a trailer wheel, wherein the control means performs the traveling during the automatic deceleration. Further evaluation result a detection signal from the state detection signal, when the steering tendency of the vehicle is shifted to oversteer, the automatic deceleration control apparatus for a combination vehicle, characterized in that to reduce the automatic braking force of the tractor wheels.