JP3539998B2 - Electronically controlled brake system for vehicles - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an electronic control brake device for a vehicle.
[0002]
[Prior art]
2. Description of the Related Art As a conventional electronic control brake device for a vehicle, for example, one disclosed in Japanese Patent Application Laid-Open No. 4-176766 is known. This device detects an operation displacement amount and an operation force of a brake pedal, and controls a change amount of a wheel braking force based on the operation displacement amount or a change amount of the operation force.
[0003]
[Problems to be solved by the invention]
However, when the driver needs sudden braking, the above-described device detects the operation displacement amount and the operation force of the brake pedal, and changes the wheel control force based on the operation displacement amount or the change amount of the operation force. Since the amount is controlled, sudden braking cannot be determined unless the brake pedal is operated to some extent, and there is a problem that the braking force is momentarily delayed at the start of operation of the brake pedal, and the braking distance becomes longer.
[0004]
Accordingly, an object of the present invention is to provide an electronically controlled brake device for a vehicle that can reduce a braking distance when a driver needs sudden braking.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a brake operation detector that detects an operation amount or an operation force of a brake operation member, an actuator for generating a braking force, and a start of a brake operation is detected by the brake operation detector Then, in relation to the accelerator operation, braking force characteristic determining means for determining a braking force characteristic defining a relationship between a braking operation amount or an operating force and a braking force for applying a required braking force, and Control means for controlling the drive of the actuator so as to generate a braking force according to the operation amount or the operation force of the brake operation member by the brake operation detector so as to have the braking force characteristic determined by the power characteristic determination means. The gist of the present invention is an electronic control brake device for a vehicle.
[0006]
According to a second aspect of the present invention, the braking force characteristic determining means according to the first aspect of the present invention is configured such that the operation amount at the time of returning the accelerator operation member or the temporal change amount of the operation force and the accelerator operation are terminated. The gist of the present invention is an electronic control brake device for a vehicle in which a braking force characteristic is determined based on a time from when the braking operation is started until the braking operation is started.
[0007]
[Action]
According to the first aspect of the present invention, when the start of the brake operation is detected by the brake operation detector, the braking force characteristic determining means applies the required braking force in relation to the accelerator operation. A braking force characteristic that defines the relationship of the braking force to the amount or the operating force is determined. That is, as soon as the brake operation is started, the braking force characteristic according to whether or not the sudden braking operation is performed in relation to the accelerator operation is determined. The control means drives and controls the actuator to generate a braking force according to the operation amount or the operation force of the brake operation member by the brake operation detector so that the braking force characteristic determined by the braking force characteristic determination means is obtained. .
[0008]
According to a second aspect of the present invention, in addition to the operation of the first aspect, the braking force characteristic determining means includes an operation amount or a time change amount of the operation force when the accelerator operation member is returned. The braking force characteristic is determined by the time from the end of the accelerator operation to the start of the brake operation. Therefore, it is reliably determined whether or not a sudden braking operation has been performed.
[0009]
【Example】
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall configuration diagram of an electronic control brake device for a vehicle according to the present embodiment.
[0010]
A reaction force generator 2 is connected to a brake pedal 1 as a brake operation member. The reaction force generator 2 generates a reaction force according to the amount of depression of the brake pedal 1, and a spring or the like is used. The relationship between the amount of depression of the brake pedal 1 and the generated reaction force in the reaction force generation device 2 is as shown in FIG. 2, and an operation feeling equivalent to that of a general hydraulic brake device can be obtained.
[0011]
Further, the brake pedal 1 is provided with a brake operation amount detection sensor 3 as a brake operation detector for detecting a depression operation amount of the brake pedal 1. The brake operation amount detection sensor 3 is composed of a potentiometer, and outputs a signal corresponding to a depression operation amount (stroke amount) of the brake pedal 1.
[0012]
The accelerator pedal 4 serving as an accelerator operation member is provided with an accelerator operation amount detection sensor 5 for detecting a depression operation amount of the accelerator pedal 4. The accelerator operation amount detection sensor 5 includes a potentiometer, and outputs a signal corresponding to the operation amount of the accelerator pedal 4.
[0013]
The controller 6 as the braking force characteristic determining means and the control means is mainly composed of a microcomputer. The brake operation amount detection sensor 3 and the accelerator operation amount detection sensor 5 are connected to the controller 6. The brake operation amount signal corresponding to the brake operation amount is input from the brake operation amount detection sensor 3 to the controller 6. , An accelerator operation amount signal corresponding to the accelerator operation amount is input.
[0014]
On the other hand, each wheel of the vehicle is provided with a wheel brake 7. A disk brake type brake is used for the wheel brake 7, and the disk brake type brake brakes a disk which rotates integrally with a wheel by sliding a pad by sliding a wheel cylinder. The pressure of the wheel cylinder of the disc brake type brake is controlled by a hydraulic control device 8 as an actuator.
[0015]
The controller 6 calculates a braking force based on the brake operation amount and the accelerator operation amount, and sends a braking force signal to each hydraulic pressure control device 8.
The relationship between the command value Fs of the braking force signal and the braking force generated by the wheel brake 7 is substantially proportional as shown in FIG. 3, and the greater the command value Fs of the braking force signal, the greater the braking force. Become.
[0016]
Next, the operation of the electronically controlled brake device for a vehicle configured as described above will be described.
FIG. 4 shows a flowchart executed by the controller 6. FIG. 5 shows changes in the accelerator operation amount and the brake operation amount. In FIG. 5, it is assumed that the accelerator operation is performed until the timing of t1, and the brake operation is performed from the timing of the subsequent t2.
[0017]
In step 100 of FIG. 4, the controller 6 reads the value of the brake operation amount signal (brake operation amount) Bs and the value of the accelerator operation amount signal (accelerator operation amount) As. Then, the controller 6 determines whether or not the brake pedal 1 is operated in step 101. If the brake pedal 1 is not operated (Bs = 0), in step 102, it is determined whether or not the accelerator pedal 4 is operated. Judge. If the brake pedal 1 is not operated and the accelerator pedal 4 is operated (Bs = 0, As> 0), the controller 6 determines in step 103 the current value As and the previous value Aso of the accelerator operation amount signal. Is calculated and stored as a change amount δAs (= As−Aso). Then, in step 104, the controller 6 stores As as Aso in preparation for the next routine.
[0018]
Before the timing of t1 in FIG. 5, steps 100 → 101 → 102 → 103 → 104 → 100... Are repeated.
When the driver releases the accelerator pedal 4 for braking (timing of t1 in FIG. 5), the controller 6 proceeds to step 105 because As = 0 in step 102. In step 105, the controller 6 determines whether or not the accelerator operation amount As is switched from a positive value to “0”. This time (timing t1 in FIG. 5), the accelerator operation amount As changes from a positive value to “0”. Therefore, the process proceeds to step 106 to store the time Taoff at which the operation of the accelerator pedal 4 is completed. Thereafter, the controller 6 returns to Step 100.
[0019]
In the next process, the accelerator operation amount As is not switched from a positive value to "0" in step 105, so that step 106 is bypassed.
In the period from t1 to t2 in FIG. 5, steps 100 → 101 → 102 → 105 → 100... Are repeated.
[0020]
Thereafter, when the driver steps on the accelerator pedal 4 to the brake pedal 1 and starts the brake operation (timing at t2 in FIG. 5), the controller 6 proceeds to step 107 because Bs> 0 in step 101. . The controller 6 determines in step 107 whether or not the brake operation amount Bs is switched from “0” to a positive value. This time (timing t2 in FIG. 5), the brake operation amount is changed from “0” to a positive value. Since the switching is performed, the time Tbon at which the operation of the brake pedal 1 is started is stored in step 108. Further, the controller 6 subtracts the time Taoff at which the operation of the accelerator pedal 4 ends from the time Tbon at which the operation of the brake pedal 1 starts at step 109, and depresses the time Tab (= Tbon− Taoff). Then, at step 110, the controller 6 determines a function f (braking force characteristic) for obtaining a braking force corresponding to the brake operation amount Bs based on the step change time Tab and the change amount δAs of the accelerator operation amount.
[0021]
Here, as shown in FIG. 6, the function f is proportional to the brake operation amount Bs as the step change time Tab from the accelerator pedal 4 to the brake pedal 1 is shorter and the absolute value of the change amount δAs of the accelerator operation amount As is larger. The inclination of the braking force (the inclination of the command value Fs of the braking force signal) is set to be large. That is, as shown by the solid line in FIG. 5, when the return speed of the accelerator pedal 4 is small (| δAs | is small) and the step-over time Tab from the accelerator pedal 4 to the brake pedal 1 is long, the function f becomes It is set as shown by the solid line. When the return speed of the accelerator pedal 4 is large (| δAs '| is large) and the step change time Tab' from the accelerator pedal 4 to the brake pedal 1 is short as shown by the broken line in FIG. It is set as shown by the broken line in FIG.
[0022]
Thereafter, the controller 6 determines the braking force for the brake operation amount Bs using the function f in step 111 of FIG. 4 and sends a braking force signal to the hydraulic pressure control device 8. The hydraulic pressure control device 8 receives the braking force signal, and the wheel brake 7 operates. After the processing of step 111, the controller 6 returns to step 100.
[0023]
In the next process, since the brake operation amount Bs is not switched from “0” to a positive value in step 107, the process proceeds from step 107 to step 111.
[0024]
Steps 100 → 101 → 107 → 111 → 100... Are repeated while the brake operation is being performed after the timing of t2 in FIG. At this time, the wheel brake 7 is operated using the function f selected at the start of the operation of the brake pedal 1 in step 111 so that the braking force corresponds to the brake operation amount Bs. That is, the hydraulic pressure control device 8 is drive-controlled to generate a braking force corresponding to the brake operation amount Bs so as to have the braking force characteristic determined at the start of the brake operation.
[0025]
As described above, at the start of operation of the brake pedal 1 after the operation of the accelerator pedal 4 is completed, as shown by the solid line in FIG. 5, in the case of normal braking that does not require the driver to perform sudden braking, | δAs | Since it is small and Tab is long, the function f indicated by the solid line in FIG. 6 is set, and a normal braking force is obtained with respect to the brake operation amount Bs. In the case of sudden braking, as shown by the broken line in FIG. 5, since | δAs ′ | is large and Tab ′ is short, the function f indicated by the broken line in FIG. 6 is set, and the brake operation amount Bs is set. As a result, the braking force generated increases, and as a result, the braking distance is reduced.
[0026]
As described above, in the present embodiment, when the start of the brake operation is detected by the brake operation amount detection sensor 3 (the brake operation detector), the controller 6 (the control means, the braking force characteristic determining means) performs the connection with the accelerator operation. In the above, the function f (braking force characteristic) for giving the required braking force is determined. Therefore, immediately after the brake operation is started, a function f (braking force characteristic) is determined according to whether or not a sudden braking operation is performed in relation to the accelerator operation, and the braking force according to the operation amount of the brake pedal 1 is determined by the function f. Is given, when the driver needs sudden braking, the braking distance can be reduced.
[0027]
Further, the controller 6 calculates the temporal change amount δAs of the operation amount at the time of the return operation of the accelerator pedal 4 (accelerator operation member) and the step change time Tab from the end of the accelerator operation to the start of the brake operation. The function f (braking force characteristic) was determined. That is, when the returning speed of the accelerator pedal 4 is high and the time for changing over from the accelerator pedal 4 to the brake pedal 1 is short, such as when the driver needs sudden braking, it is determined to be a sudden braking operation. Can be. As a result, the braking distance can be reliably reduced by previously setting a large braking force to the brake operation amount.
[0028]
Note that the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the braking force is controlled by controlling the pressure of the wheel cylinder of the disc brake type brake by the hydraulic pressure control device 8, A braking device of a type that controls the braking force may be used.
[0029]
In addition, instead of the brake operation amount detection sensor 3, an operation force of the brake pedal 1, that is, an operation force detection sensor for detecting a depression force is used to generate a braking force corresponding to the operation force (depression force) of the brake pedal 1. The drive of the pressure control device 8 may be controlled. As the operation force detection sensor, for example, a strain gauge is used.
[0030]
Further, instead of the accelerator operation amount detection sensor 5, an operation force detection sensor that detects the depression force (operation force) of the accelerator pedal 4 is used, and the time change amount of the depression force (operation force) when the accelerator pedal 4 is returned is calculated. Alternatively, the function f (braking force characteristic) may be determined based on the time from the end of the accelerator operation to the start of the brake operation. As the operation force detection sensor, for example, a strain gauge is used.
[0031]
【The invention's effect】
As described in detail above, according to the first aspect of the present invention, the braking force characteristic for the sudden braking operation is determined immediately after the braking operation is started. In addition, the braking distance can be reduced. According to the second aspect of the present invention, in addition to the effect of the first aspect, it is possible to reliably determine the sudden braking operation.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an electronic control brake device according to an embodiment.
FIG. 2 is a characteristic diagram of a reaction force generator for a brake pedal.
FIG. 3 is a characteristic diagram showing a relationship between a braking command value sent from a controller and a braking force generated by a wheel brake.
FIG. 4 is a flowchart illustrating an operation.
FIG. 5 is a time chart for explaining an operation.
FIG. 6 is a characteristic diagram of a function f for determining a braking force from a brake operation amount.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Brake pedal as a brake operation member, 3 ... Brake operation amount detection sensor as a brake operation detector, 4 ... Accelerator pedal as an accelerator operation member, 5 ... Accelerator operation amount detection sensor, 6 ... Brake force characteristic determination means and Controller as control means, 7 ... wheel brake, 8 ... hydraulic pressure control device as actuator

Claims (2)

A brake operation detector that detects an operation amount or an operation force of a brake operation member,
An actuator for generating a braking force,
When the start of the brake operation is detected by the brake operation detector, in relation to the accelerator operation, a braking force that defines the relationship between the braking force and the braking force for applying the required braking force in relation to the accelerator operation. Braking force characteristic determining means for determining characteristics;
Control means for controlling the drive of the actuator so as to generate a braking force corresponding to an operation amount or an operation force of a brake operation member by the brake operation detector so as to have a braking force characteristic determined by the braking force characteristic determination means; An electronically controlled brake device for a vehicle, comprising: The braking force characteristic determining means determines a braking force characteristic by an operation amount or a temporal change amount of an operation force at the time of a return operation of an accelerator operation member and a time from the end of the accelerator operation to the start of the brake operation. The electronic control brake device for a vehicle according to claim 1, which is to be determined.

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