JP2979705B2 - Braking force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device for controlling a brake of a wheel so that an actual deceleration of a vehicle body follows a target deceleration, and more particularly to a technique for improving the performance thereof. It is.

[0002]

2. Description of the Related Art The following is already known as an example of the braking force control device. This is, as described in the applicant's JP-A-63-20256,
(a) brake operation amount detection means for detecting a brake operation amount which is an operation force or operation stroke of a brake operation member such as a brake pedal; (b) deceleration detection means for detecting a vehicle deceleration; (c) An actuator for controlling wheel brakes provided on the vehicle body; and (d) determining a target deceleration of the vehicle body according to the brake operation amount detected by the brake operation amount detection means, and determining the deceleration detected by the deceleration detection means. The controller is configured to determine a control amount of the actuator based on a deceleration deviation that is a deviation of the speed from the target deceleration, and to control the actuator in accordance with the determined control amount. By using this type of braking force control device, it is possible to respond to the driver's will without being affected by disturbances such as changes in the friction coefficient of the brake friction material, changes in the gradient of the road surface on which the vehicle runs, and changes in the gross vehicle weight. A large amount of braking deceleration is realized.

[0003]

However, research by the present applicant has revealed that this braking force control device has the following problems. In other words, this braking force control device is capable of increasing the deceleration of the vehicle body even if the vehicle speed is 0 and the vehicle deceleration can no longer be increased when the brake operation is performed while the vehicle is stopped when the vehicle speed is 0. Since the actuator control amount for compensating for the deceleration deviation is determined, it has been found that there is a problem that if the actuator and the brake are controlled in accordance therewith, an extra load is applied to the actuator and the like. Based on the above findings,
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem by changing an actuator control amount according to a vehicle speed in a braking force control device.

[0004]

The gist of the present invention is, as shown in FIG. 1, a braking force control device including the operation amount detection means 1, deceleration detection means 2, actuator 3, and actuator control means 4. , The vehicle speed detecting means 5 for detecting the vehicle speed is provided, and the actuator control means is increased as the deceleration deviation increases.
Detected by the deceleration-related change amount and the operation amount detection means
The amount of brake operation related to the amount of brake operation increases
And the amount of change related to brake operation that increases as
To determine the actuator control amount, and
That is , the amount of change is determined to be 0 when the vehicle speed is 0 . Actuator control means
Speed related changes decrease as vehicle speed decreases
However , it is desirable that the vehicle speed be determined to be 0 when the vehicle speed becomes 0 .

[0005] The brake operation amount itself may be selected as the brake operation related amount, or a parameter uniquely determined according to the brake operation amount may be selected.

[0006]

The braking force control device according to the present invention comprises an actuator
Control amount is increased as the deceleration deviation increases.
As the speed-related change amount and the brake operation-related amount increase,
To the sum of the brake operation-related changes that increase
Together with the deceleration-related change when the vehicle speed is 0
Is determined to be 0. Therefore, when the vehicle speed is 0, no actuator control amount for compensating for the deceleration deviation is generated, and only the actuator control amount corresponding to the brake operation-related amount is generated.

[0007]

As a result, it is not necessary to apply an extra load to the actuator and the brake when the vehicle is stopped , so that the effect of improving the performance of the braking force control device can be obtained. Also, as the vehicle speed decreases,
In a desirable mode in which the amount of change is gradually reduced
Has a good driving feel by preventing a sudden change in actual deceleration.
This has the effect that realization is realized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric / manual two-system brake device for a four-wheel vehicle including a braking force control device according to an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 2, reference numeral 10 denotes a master cylinder, to which a brake pedal 14 as a brake operating member is connected. The master cylinder 10 generates a hydraulic pressure in the pressurizing chamber according to the depression of the brake pedal 14. The hydraulic pressure generated in the pressurized chamber is
6, 18, 20 and 22 to the wheel cylinder 30 of a friction type brake 24 (which is an embodiment of the brake in the present invention) of the left and right front wheels, and to the left and right rear wheels via oil passages 32 and 34. Brake 2
4 is transmitted to the wheel cylinder 30. A proportioning valve 42 is provided in the oil passage 32. The above is the same as a normal manual brake device.

An electromagnetic directional control valve 50 is provided between the oil passages 20, 32 and the oil passages 22, 34. A hydraulic source 60 is connected to the electromagnetic directional switching valve 50 by an oil passage 58. The hydraulic pressure source 60 includes a reservoir 70, a pump 7
2, accumulator 74 and four actuators 8
0 is provided. The accumulator 74 has a pressure sensor 8
2 is attached, and a controller 90 mainly composed of a computer is operated by an electric motor 92
, The accumulator 74 is configured to store the brake fluid in a certain hydraulic range. The actuator 80 controls the hydraulic pressure by moving the spool to switch the direction of the flow of brake oil based on the relative relationship between the magnetic driving force based on the exciting current and the fluid reaction force based on the hydraulic pressure. A pressure control valve,
This is to generate a brake pressure having a height proportional to the exciting current. An electromagnetic directional control valve 116 is connected between the oil passages 16 and 18. An oil absorber 118 is connected to the electromagnetic direction switching valve 116. The oil absorber 118 absorbs an amount of brake oil proportional to the oil pressure under pressure.

The controller 90 is connected to a pedaling force sensor 120 for detecting a pedaling force value of the brake pedal 14, a vehicle speed sensor 122 for detecting a vehicle speed which is a vehicle speed, and a deceleration sensor 124 for detecting a vehicle deceleration. The ROM of the computer of the controller 90 stores various programs including a braking force control routine shown in the flowchart of FIG.

The controller 90 includes the electromagnetic directional control valve 50,
116 is controlled. Specifically, the accumulator 74 stores a hydraulic pressure of a normal height, the pedaling force sensor 120 is normal, and the four actuators 80
In a state where everything is normal (hereinafter simply referred to as a state where the hydraulic pressure source 60 is normal), the wheel cylinder 30 is disconnected from the master cylinder 10 to communicate with the hydraulic pressure source 60 and the master cylinder 10 is connected to the oil absorber 118. If not, the wheel cylinder 30 is disconnected from the oil pressure source 60 to communicate with the master cylinder 10, and the master cylinder 10 is controlled to be disconnected from the oil absorber 118.

The braking force control device 130 is constituted by the actuator 80, the controller 90, the pedaling force sensor 120, the vehicle speed sensor 122, and the deceleration sensor 124 among the components described above. This braking force control device 13
FIG. 4 shows a configuration as a control system of 0 and how signals are transmitted in this control system. In the figure, the deceleration detecting means 140 is constituted by the deceleration sensor 124, the low-pass filter 142, and the deceleration determining means 144. Since the sensor signal from the deceleration sensor 124 is usually formed by superimposing a signal affected by the deceleration of the vehicle body and a signal affected by the vibration of the vehicle body (for example, the influence of road surface noise), the low-pass filter is used. The vehicle body deceleration component is obtained by removing the vehicle body vibration component from the sensor signal by using the sensor signal 142, and the deceleration determining means 144 determines the deceleration using this. The target oil pressure determining means 146 is a means for determining a target oil pressure of the actuator 80 (which is also a target oil pressure of the brake 24) in accordance with a treading force value detected by the treading force sensor 120. S1; the same applies to the other steps) and S2. The target deceleration determining means 150 is means for determining the target deceleration of the vehicle body in accordance with the pedaling force value, and is constituted by a part of the controller 90 that executes S1 and S3. Feedback gain determination and limit means 1
Reference numeral 52 denotes a part of the controller 90 for executing S5 to S7.

In this control system, the deceleration detecting means 14 is provided by a portion of the controller 90 for executing S4.
A signal representing the deceleration deviation of the detected deceleration from the target deceleration by 0 is supplied to the feedback gain determination and limit means 152, and the feedback gain determination and limit means 152 is provided by the part of the controller 90 which executes S8 and S9. An excitation signal for realizing the sum of the feedback control amount from the controller and the feedforward control amount indicating the target oil pressure determined by the target oil pressure determining means 140 is output to the actuator 80.

The present braking force control device 1 schematically described above
The operation of the brake device 30 will be described in detail with reference to the flowchart of FIG. 3, and the operation of the entire brake device will be briefly described. However, only the state where the hydraulic pressure source 60 is normal will be described, and the description of the state where the hydraulic source 60 is abnormal will be omitted.

At the same time when the ignition switch of the vehicle is turned on, an initial setting (not shown) is performed. In addition,
When the power of the controller 90 is not turned on, the electromagnetic directional control valves 50 and 116 disconnect the wheel cylinder 30 from the hydraulic pressure source 60 to communicate with the master cylinder 10 and disconnect the master cylinder 10 from the oil absorber 118. In state. Therefore, the controller 90
When the power is turned on, it is assumed that the hydraulic pressure source 60 is normal this time.
And the hydraulic pressure of the hydraulic pressure source 60 is transmitted to the wheel cylinder 30 instead of the hydraulic pressure of the master cylinder 10.

If the brake pedal 14 is depressed in this state, hydraulic pressure is generated in the master cylinder 10. At this time, the brake oil is discharged from the master cylinder 10 and stored in the oil absorber 118 in response to the depression of the brake pedal 14, and as a result, the operation feeling of the brake pedal 14 becomes moderately soft. Master cylinder 10
The hydraulic pressure generated in each actuator 80 is transmitted to the wheel cylinder 30 by the controller 90 repeatedly executing the braking force control routine of FIG. Less than,
The manner in which the braking force control routine is executed will be described.

First, at step S1, the pedaling force value detected by the pedaling force sensor 120 is input. Next, in S2, according to the treading force value F, a predetermined relationship between the treading force value F and the target oil pressure P ^* (the relationship shown in the graph of FIG.
According to the target hydraulic pressure P ^* (stored in the ROM) (this is one aspect of the brake operation-related amount in the present invention).
Is determined. The height of the target oil pressure P ^* is represented as a feedforward control amount. Subsequently, in S3,
In accordance with the pedaling force value F, the target deceleration G is calculated according to a predetermined relationship between the pedaling force value F and the target deceleration G ^* (the relationship shown in the graph of FIG. 6 and stored in the ROM).
^* Is determined. Thereafter, in S4, the deceleration G detected by the deceleration detecting means 140 is input, and the deceleration deviation e of the detected deceleration G from the target deceleration G ^* is calculated. Subsequently, in S5, the vehicle speed V detected by the vehicle speed sensor 122 is input, and in S6, a predetermined relationship between the vehicle speed V and the feedback gain K according to the vehicle speed V (shown in the graph of FIG. 7). Relationship, ROM
Is stored in the feedback gain K. The feedback gain K is 0 when the vehicle speed V is 0, as shown in FIG.
Increases as the vehicle speed V increases, and is kept constant after the vehicle speed V reaches the constant Vo. Further, in this step, a feedback control amount indicating a target oil pressure change amount which is a product of the deceleration deviation e and the feedback gain K is determined.

Then, in S7, the deceleration deviation e
According to the relationship between the deceleration deviation e and the limit value LMT (the relationship shown in the graph of FIG.
(Stored in the OM), and the limit value LMT is determined. When the absolute value of the feedback control amount is larger than the absolute value of the limit value LMT, the feedback control amount is limited to the limit value LMT. In S8, the sum of the feedforward control amount and the feedback control amount is determined as an appropriate control amount, and in S9, an excitation signal corresponding to the appropriate control amount is output to the actuator 80.
Is output to This completes one execution of this routine.

By the way, in the conventional device, the feedback control is performed when the vehicle stops when the vehicle speed V becomes completely zero, so that the deceleration deviation e is compensated even though the actual deceleration G can no longer be increased. A brake pressure is generated, and an extra load is applied to the actuator 80. However, in this embodiment, when the vehicle speed V is 0, the feedback gain K is set to 0, the feedback control is omitted, and the brake pressure is controlled only by the feedforward control. Therefore, even when the brake pedal 14 is depressed when the vehicle is stopped, a brake pressure having a height corresponding thereto (a brake pressure having substantially the same height as in a normal manual brake device) is generated, and the actuator 80 The effect that such a burden is reduced is obtained. Further, in the present embodiment, the feedback gain K is determined so as to continuously decrease as the vehicle speed V decreases, so that the feedback control is gradually omitted in the process of decreasing the vehicle speed V to 0, and the actual deceleration is reduced. The effect of preventing a sudden change in G and realizing a good running feeling is also obtained.

In this embodiment, the deceleration deviation e
The brake pressure is controlled by the feedback control based on the brake pressure and the feedforward control based on the target oil pressure G ^* (pedal force value F). The effect that the deviation is compensated is also obtained.

In a conventional manual brake system, when a heat fade occurs in the brake 24 during braking of the vehicle, the feeling of deceleration is insufficient, so that the driver can notice the occurrence of the heat fade. Therefore, if the feedback control always generates a brake pressure that compensates for the deceleration deviation e, the driver does not notice the deceleration feeling even if the heat fade occurs, and the driver notices the occurrence of the heat fade. Can not. However, in the present embodiment, the deceleration deviation e
Is provided, so that the excessive deceleration deviation e does not generate a brake pressure having a height that completely compensates for it, thereby permitting insufficient deceleration feeling. Therefore, the effect that the driver can easily notice the occurrence of the heat fade is also obtained.

As is apparent from the above description, in this embodiment, the pedaling force sensor 120 constitutes the operation amount detecting means, the vehicle speed sensor 122 constitutes the vehicle body speed detecting means, the target oil pressure determining means 146, and the target pressure reducing means. Speed determining means 150, feedback gain determining and limiting means 152,
The part of the controller 90 that executes S4, S8, and S9 in FIG. 3 constitutes the actuator control means.

In the embodiment described above, the feedback gain K is continuously reduced as the vehicle speed V decreases. For example, if the vehicle speed V is not zero, a constant value other than zero is used. And if 0, 0
May be changed step by step. If the vehicle speed V is 0, only the feedforward control is performed. If the vehicle speed V is larger than 0, the feedforward control and the feedback control (regular feedback control in which the feedback gain K takes a regular value) are performed jointly. You may do it.

[0025]

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention may be embodied in various other modified and improved forms based on the knowledge of those skilled in the art. It is possible.

[Brief description of the drawings]

FIG. 1 is a diagram conceptually showing the configuration of the present invention.

FIG. 2 is a system diagram showing an electric / manual dual system brake device for a four-wheel vehicle including a braking force control device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration as a control system of the braking force control device and how signals are transmitted in the control system.

FIG. 4 is a flowchart showing a braking force control routine in the braking force control device.

FIG. 5 is a graph showing a map used by the braking force control routine.

FIG. 6 is a graph showing a map used by the braking force control routine.

FIG. 7 is a graph showing a map used by the braking force control routine.

FIG. 8 is a graph showing a map used by the braking force control routine.

[Explanation of symbols]

 Reference Signs List 14 brake pedal 24 brake 80 actuator 90 controller 120 pedaling force sensor 122 vehicle speed sensor 130 braking force control device 140 deceleration detecting means 146 target oil pressure determining means 150 target deceleration determining means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60T 8/32 B60T 13/66 B60T 17/18

Claims (2)

(57) [Claims] 1. An operation amount detection means for detecting a brake operation amount; a deceleration detection means for detecting a deceleration of a vehicle body; an actuator for controlling a brake of a wheel provided on the vehicle body; A target deceleration of the vehicle body is determined in accordance with the brake operation amount detected by the control unit, and a deviation of the deceleration detected by the deceleration detecting means from the target deceleration is determined.
An actuator control means for determining a control amount of the actuator based on the difference in deceleration and controlling the actuator in accordance with the determined actuator control amount; a vehicle speed detecting means for detecting a vehicle speed And the actuator control means increases the deceleration deviation.
A deceleration-related change amount increases as that, the brake
As the amount of brake operation related to the amount of operation increases,
As the sum of the brake operation-related change
Determine the actuator control amount and change the deceleration-related variable.
A braking force control device characterized in that the amount of change is determined to be zero when the vehicle speed is zero . 2. The vehicle control system according to claim 1, wherein the actuator control means includes:
It decreases as the vehicle speed decreases, and becomes zero when the vehicle speed becomes zero.
The deceleration-related change amount is determined so that
The braking force control device according to claim 1, wherein: