WO2023167165A1

WO2023167165A1 - Vehicle behavior control device

Info

Publication number: WO2023167165A1
Application number: PCT/JP2023/007244
Authority: WO
Inventors: 公彦阿部
Original assignee: 三菱自動車工業株式会社
Priority date: 2022-03-02
Filing date: 2023-02-28
Publication date: 2023-09-07

Abstract

This vehicle-behavior control device causes brake devices on the respective wheels of a vehicle to operate and generate an individual braking force for each wheel, thereby determining, while brake control that realizes vehicle braking according to a prescribed total braking force is underway, whether any wheel is in an unweighted state in which traction load thereon is lost, on the basis of the operational state of the vehicle. With respect to braking-force shortage, which is the individual braking force on a wheel that has been determined to be in the unweighted state, the vehicle-behavior control device adds a brake-device operational amount corresponding to a portion or the entirety of the braking-force shortage as the operational amount of any one or more of the brake devices corresponding to the wheels that have not been determined to be in the unweighted state.

Description

Vehicle behavior control device

The present disclosure relates to a vehicle behavior control device that operates brake devices corresponding to each wheel to control the behavior of the vehicle.

In recent years, there has been known a vehicle configured to perform brake control, such as realizing braking of the vehicle with a predetermined total braking force by operating a brake device corresponding to each wheel (see Patent Document 1). . With this brake control, it is possible to support the running of the vehicle while maintaining a predetermined total braking force on a steep slope or a slippery slope.

Japanese Patent Application Laid-Open No. 2012-206679

However, with the above configuration, depending on the road surface conditions, some of the wheels may leave the road surface, resulting in a state in which the ground contact load is lost. There is concern that a decline will result. Such a decrease in braking force is not desirable because it causes problems such as giving the passenger a feeling of idle running and causing unintended speed fluctuations and wheel slips.

The present disclosure has been made to solve such problems, and its purpose is to suppress problems caused by a significant decrease in braking force in brake control.

A vehicle behavior control device according to the present disclosure operates a braking device for each wheel of a vehicle to generate an individual braking force for each wheel, thereby performing brake control that realizes braking of the vehicle with a predetermined total braking force. Among them, unweighted determination means for determining whether or not each wheel is in an unweighted state in which the ground load of each wheel is unloaded based on the operating state of the vehicle; With respect to the braking force, the operation amount of one or more brake devices corresponding to the wheels that are not determined to be in the unweighted state is added as the operation amount of the brake device corresponding to part or all of the insufficient braking force. a means;

According to this vehicle behavior control device, when some of the wheels are in an unweighted state, an operation amount corresponding to part or all of the insufficient braking force is added to the brake devices corresponding to the other wheels to additionally individual braking force can be generated. In this way, the insufficient braking force due to the unweighted wheel is compensated for by the other wheels, so that the total braking force required for brake control is not significantly lowered. As a result, it is possible to prevent the occupants from feeling that the vehicle is running idle, and to prevent the occurrence of unintended speed fluctuations and wheel slippage.

According to the present disclosure, it is possible to provide a vehicle behavior control device capable of suppressing the occurrence of defects caused by failure to maintain the total braking force in brake control.

Block diagram showing the overall configuration of a vehicle according to the present disclosure Flowchart showing processing procedure of motion addition processing

Embodiments of the present disclosure will be described below based on the drawings.

(1) Overall Configuration Vehicle 1, as shown in FIG. , a stroke sensor 50 provided in each suspension device 40, an acceleration sensor 60 for detecting the acceleration of the vehicle 1, a vehicle speed sensor 70 for detecting the speed of the vehicle 1, and controlling the operation of the entire vehicle 1 A vehicle behavior control device 80, which is an ECU (Electronic Control Unit) for

In this embodiment, the vehicle 1 includes a pair of wheels 10 arranged on the left and right in the front and a pair of wheels 10 arranged on the left and right on the rear.

The drive device 30 receives commands from the vehicle behavior control device 80 and operates each of the brake devices 20 . In this embodiment, the brake device 20 and the drive device 30 are directly or indirectly connected by a hydraulic path, and the drive device 30 receives a command from the vehicle behavior control device 80, and responds to the command to each wheel. It is configured to apply necessary hydraulic pressure to each brake device 20 in order to generate a predetermined braking force in the brake device 10 .

The stroke sensor 50 is a sensor that detects the stroke amount of a shock absorber (not shown) interposed between the vehicle body 1 and the wheel 10 in the suspension device 40 .

The acceleration sensor 60 is composed of a sensor that detects acceleration in the longitudinal direction of the vehicle 1 and a sensor that detects acceleration in the lateral direction.

(2) Action Addition Processing by Vehicle Behavior Control Device 80 Next, action addition processing performed by the vehicle behavior control device 80 will be described with reference to FIG. This operation addition process is a process executed by the vehicle behavior control device 80 according to a program stored in the built-in memory 71, and is started on the condition that the brake control process similarly executed according to the program has been started.

This brake control process is a process for brake control in which the drive device 30 generates an individual braking force for each wheel 10, thereby braking the vehicle 1 with a predetermined total braking force. In this embodiment, as the brake control, hill descent control (HDC) is implemented to assist the vehicle 1 moving forward on a steep slope or a slippery slope while maintaining a predetermined total braking force. Illustrate.

When this action addition process is activated, first, the vehicle 1 enters a standby state until the speed of the vehicle 1 detected by the vehicle speed sensor 70 reaches or exceeds a predetermined speed (30 km/h in this embodiment) (s110: NO).

If the speed becomes equal to or higher than the predetermined speed in s110 (s110: YES), it is checked based on the operation state of the vehicle 1 whether or not the ground load of each wheel 10 is in a weightless state (s120). . Here, the stroke amount detected by each stroke sensor 50 is checked, and for the stroke sensor 50 that reaches the stroke amount when the wheel 10 is off the ground, the corresponding wheel 10 is in the unweighted state. It is determined that there is

It should be noted that in this s120, in addition to the detection value of the stroke sensor 50, it may be determined that the wheel 10 with a relatively small ground load is also in the unweighted state. At this time, the ground load of each wheel 10 is estimated based on the specification values of the vehicle 1 such as the wheelbase and the height of the center of gravity, the vehicle body tilt angle calculated from the detection value of the acceleration sensor 60, the coefficient of friction of the road surface, and the like. If it is equal to or less than a predetermined threshold value, it is determined that the contact load is missing.

At s120, if none of the wheels 10 is determined to be in a weightless state (s120: NO), the process returns to s110.

On the other hand, if at least one of the wheels 10 is determined to be unweighted in s120 (s120: YES), the insufficient braking force (insufficient braking force) due to the wheel 10 determined to be unweighted is calculated ( s130). Here, among the individual braking forces generated in each wheel 10 in the brake control, the sum of the individual braking forces of the wheels 10 determined to be in the unweighted state is calculated as the insufficient braking force.

In addition, when the individual braking force generated in each wheel 10 in brake control is the same (including within a predetermined threshold value range), the insufficient braking force is "(the number of wheels 10 determined to be unweighted × individual It may be calculated based on "braking force)/number of wheels 10 not determined to be in an unweighted state".

Next, the ground load of each wheel 10 is detected (s140). Here, the ground load is detected as an estimated value calculated based on the specification values of the vehicle 1 such as the wheelbase and the height of the center of gravity, the vehicle body tilt angle calculated from the detection value of the acceleration sensor 60, the friction coefficient of the road surface, and the like. .

Next, an individual braking force for each wheel 10 required to additionally generate the insufficient braking force calculated in s130 is set (s150). Here, for each of the wheels 10 that are not determined to be in the unweighted state, the larger the ground load of the wheel 10 is, the further the wheel 10 is located in the front, and the positional relationship with the unweighted wheel 10. A large individual braking force is set for that wheel 10 .

In the present embodiment, the total value of a first coefficient corresponding to the ground contact load, a second coefficient corresponding to the front or rear wheel, and a third coefficient corresponding to the positional relationship with the unweighted wheel 10. is obtained for each wheel 10, and the individual braking force is set according to the ratio of these total values. Here, the first coefficient is set to a larger value for the wheel 10 having a larger contact load detected in s130. The second coefficient is set such that the front wheel 10 in the direction of travel (the front of the vehicle 1 in this embodiment) has a larger value than the rear wheel 10 . The third coefficient is such that the wheel 10 arranged on the same left and right side in the front-rear opposite pair of wheels 10 determined to be unweighted has a larger value than the other wheels 10 .

Here, when both the left and right wheels 10 forming a pair are included in the wheels 10 that have not been determined to be in an unweighted state, the difference in the individual braking force between the left and right wheels 10 is a predetermined threshold. At least one of the individual braking force values is adjusted so as to be equal to or less than the threshold value.

Then, a command is issued to the driving device 30 to additionally generate insufficient braking force by each of the wheels 10 that have not been determined to be in the unweighted state (s160). Here, each brake device 20 is instructed to operate by the amount of operation necessary for generating additional individual braking force set in s150 via the drive device 30, and the brake device 20 that receives this command performs additional operation. to generate individual braking force.

As a result, the amount of operation of the brake device 20 corresponding to part or all of the insufficient braking force is additionally added as the amount of operation of any one or more of the brake devices 20 corresponding to the wheels 10 that are not determined to be in the unweighted state. be done. Thus, after s160 the process returns to s110.

In the motion addition process described above, s110 is the vehicle speed detection means, s120 is the unloading determination means, s140 is the load detection means, and s160 is the motion addition means.

Although the embodiments of the present disclosure have been described above, the present disclosure is by no means limited to the above embodiments, and it goes without saying that various forms can be taken as long as they fall within the technical scope of the present disclosure. .

(3) Effects According to the vehicle behavior control device 80 of the above-described embodiment, when some of the wheels 10 are in an unweighted state, the operation amount corresponding to part or all of the insufficient braking force is adjusted to the other wheels 10 . can be added to the corresponding braking device 20 to generate an additional individual braking force. In this way, the insufficient braking force due to the unweighted wheel 10 is supplemented by the other wheels 10, so that the total braking force required for brake control is not significantly reduced. As a result, it is possible to prevent the occupants from feeling that the vehicle is running idle, and to prevent the occurrence of unintended speed fluctuations and slippage of the wheels 10 .

Further, in the vehicle behavior control device 80, when adding an operation amount corresponding to insufficient braking force to the brake device 20, the larger the wheel 10 having a larger ground load, the larger the operation amount to the brake device 20 corresponding to the wheel 10. In addition, an additional individual braking force can be generated (s150 in FIG. 2). As a result, an unnecessarily large operation amount of the brake device 20 is not distributed to the wheel 10 having a small ground load, so that the locking of the wheel 10 due to the distribution of the operation amount and the slippage of the locked wheel can be prevented.

Further, in the vehicle behavior control device 80, when applying an operation amount corresponding to the insufficient braking force to the brake device 20, the wheel 10 arranged in front of the traveling direction of the vehicle 1 has a brake device corresponding to the wheel 10. A large amount of movement can be applied to 20 to generate additional individual braking force (s150 in FIG. 2). When the vehicle 1 is braked, inertia acts, and the ground load tends to be larger toward the front wheel 10 in the traveling direction. Therefore, in the present embodiment, an unnecessarily large operation amount of the brake device 20 is not distributed to the wheels 10 having a small ground load. can prevent it from happening.

Further, the vehicle behavior control device 80 adjusts the amount of operation of the brake device 20 within a range in which the difference between the individual braking forces generated by the paired left and right wheels 10 is equal to or less than a predetermined threshold value (see FIG. 2). s150). If the difference between the individual braking forces generated by the paired left and right wheels 10 becomes large, there is a possibility that problems such as unintended turning of the vehicle 1 and differential lock of the differential gear may occur. In this respect, according to the present embodiment, the above problem can be prevented by appropriately setting the threshold value.

In addition, in the vehicle behavior control device 80, the braking devices 20 of the wheels 10 arranged on the same left and right sides of the pair of wheels 10 that are determined to be in the unweighted state are provided with a larger operation amount than the other braking devices 20. can be applied to generate an additional individual braking force (s150 in FIG. 2). As a result, another yaw moment can be generated in a direction that cancels out the yaw moment caused by the unweighted wheels 10 .

In addition, the vehicle behavior control device 80 can determine whether the wheels 10 are unweighted and generate additional individual braking force when the vehicle speed is equal to or lower than a predetermined speed.

Although various embodiments have been described above, it goes without saying that the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope described in the claims, and these also belong to the technical scope of the present invention. Understood. Moreover, each component in the above embodiments may be combined arbitrarily without departing from the spirit of the invention.

This application is based on a Japanese patent application (Japanese Patent Application No. 2022-031532) filed on March 2, 2022, the contents of which are incorporated herein by reference.

1... vehicle, 10... wheel, 20... brake device, 30... drive device, 40... suspension device, 50... stroke sensor, 60... acceleration sensor, 70... vehicle speed sensor, 71... built-in memory, 80... vehicle behavior control device.

Claims

During the execution of brake control that realizes braking of the vehicle with a predetermined total braking force by operating the braking device of each wheel in the vehicle and generating individual braking force for each wheel, based on the operating state of the vehicle unloaded weight determination means for determining whether or not the ground contact load of each wheel is in an unloaded state,
For the insufficient braking force, which is the individual braking force of the wheels determined to be in the unweighted state, the amount of operation of the brake device corresponding to part or all of the insufficient braking force corresponds to the wheels not determined to be in the unweighted state. an operation adding means for adding as an amount of operation of one or more brake devices;
A vehicle behavior control device comprising:
Equipped with load detection means for detecting the ground load of each wheel,
The motion adding means increases the ratio of the amount of motion applied to the braking device of the wheel as the ground load detected by the load detecting means increases.
The vehicle behavior control device according to claim 1.
The motion addition means increases the ratio of the motion amount applied to the braking device of the wheel as the wheel is positioned further forward in the direction of travel of the vehicle.
The vehicle behavior control device according to claim 1.
When the vehicle is equipped with a pair of wheels arranged on the left and right,
The action addition means adds an action amount within a range in which the difference between the individual braking forces generated by the paired left and right wheels is equal to or less than a predetermined threshold value.
The vehicle behavior control device according to claim 1.
When the vehicle comprises a pair of wheels arranged on the left and right sides in front and a pair of wheels arranged on the left and right sides on the rear side,
The operation adding means increases the ratio of the amount of operation applied to the brake device of the wheel arranged on the same left and right side in the pair of wheels that are determined to be in the unweighted state, the amount of motion being added to the brake device of the other wheels. ,
The vehicle behavior control device according to claim 1.
Equipped with vehicle speed detection means for detecting vehicle speed,
The determination by the unloading determination means and the addition of the motion amount by the motion addition means are performed when the vehicle speed detected by the vehicle speed detection means is equal to or lower than a predetermined speed.
The vehicle behavior control device according to claim 1.
When the shock absorber of the suspension device corresponding to each wheel is equipped with a stroke sensor for detecting the stroke amount,
When the stroke amount detected by the stroke sensor is a stroke amount reached when the wheel is off the ground, the unweighted determination means determines that the wheel corresponding to the stroke sensor is in the unweighted state. determine that
The vehicle behavior control device according to any one of claims 1 to 6.
Load detection means for detecting the ground load of each wheel,
When the ground contact load detected by the load detection means is equal to or less than a predetermined threshold value, the weightless determination means determines that the wheel having the ground load is in the weightless state.
The vehicle behavior control device according to any one of claims 1 to 6.