JP5169739B2 - Braking control system - Google Patents

Description

  The present invention relates to a braking control system having an on / off valve (ON / OFF valve) in a brake fluid pressure path for generating a brake braking pressure.

Conventionally, as a braking control system provided with a hydraulic friction braking device, a “vehicle braking system” (which can obtain a good braking feeling, in particular, a feeling of increased braking effectiveness by performing appropriate control) ( Patent Document 1) is known.
The brake hydraulic pressure path that generates the brake braking pressure has an on / off valve (on / off valve) that controls the pressure of the wheel cylinder arranged downstream of the hydraulic pressure path.
JP 2004-338582 A

  However, since the pressure regulating valve that controls the pressure in the wheel cylinder is an on / off valve, fluid pressure fluctuations occur when the valve is opened, resulting in poor controllability. Sound and brake pedal tremors occur.

  The brake control system according to the present invention performs brake assist control so that the wheel cylinder pressure of the left and right braking force distribution non-control wheels is returned to the brake operation pressure by the driver when the left and right braking force distribution control intervenes during the brake assist control. It is characterized by being terminated.

  According to the present invention, since the pressure increase by the pressure regulating valve that is an on / off valve that controls the pressure of the wheel cylinder is not performed, the hydraulic pressure fluctuation that occurs when the valve is opened does not occur, the vehicle behavior change or It is possible to prevent vibration noise and brake pedal tremors from occurring.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing the configuration of the braking control system according to the first embodiment of the present invention. As shown in FIG. 1, the braking control system includes a braking control unit 10, a brake assist control unit 11, and an LDP control unit 12, and four wheels provided at four positions on the left and right sides of the vehicle body. Controls brake braking.
The braking control unit 10 includes a four-wheel braking force distribution first calculation unit 13, a four-wheel braking force distribution second calculation unit 14, and a four-wheel braking force distribution adjustment unit 15.

  A brake assist command from the brake assist command generation unit 11a of the brake assist control unit 11 that performs brake assist control is input to the four wheel braking force distribution first calculation unit 13, and the four wheel braking force distribution second calculation unit 14 is operated. Includes a left-right differential pressure related to a brake fluid pressure difference (left-right differential pressure) of left and right wheels from a left-right differential pressure command generation unit 12a of a lane departure prevention (LDP) control unit 12 that performs left-right braking force distribution control. A command is input.

  Brake assist control is performed to generate a braking force larger than the braking force generated by the driver's braking operation to assist (assist) the braking operation, and improve the feeling during braking by the driver. There is rise-up / build-up control (R-UP / B-UP control). The left / right braking force distribution control is performed to distribute the braking force to the left and right traveling wheels in order to prevent the traveling wheels from departing from the lane.

  The four-wheel braking force distribution first calculation unit 13 performs calculation processing for distributing braking force to the four wheels based on the input brake assist command, and outputs four-wheel braking force distribution information based on the calculation result. The four-wheel braking force distribution second calculation unit 14 performs a calculation process for allocating the braking force to the four wheels based on the input left-right differential pressure command (left-right braking force distribution control command), and the four-wheel braking wheel based on the calculation result. Outputs braking force distribution information.

  The four-wheel braking force distribution adjustment unit 15 includes four-wheel braking force distribution information based on the calculation result in the four-wheel braking force distribution first calculation unit 13 and four based on the calculation result in the four-wheel braking force distribution second calculation unit 14. Wheel braking force distribution information is input. The four-wheel braking force distribution adjustment unit 15 receives the input four-wheel braking force distribution information from the four-wheel braking force distribution first calculation unit 13 and the four-wheel braking force distribution information from the four-wheel braking force distribution second calculation unit 14. Based on the above, a four-wheel braking force distribution adjustment command for adjusting the distribution of the braking force to the four wheels is output.

A four-wheel braking force distribution adjustment command from the four-wheel braking force distribution adjustment unit 15 is input to the hydraulic servo unit 16. The brake depression force is input to the brake assist control unit 11 from the driver brake unit 17 by a driver (driver) pedal depression operation (pedal stroke). At this time, the driver brake state is set.
In this way, the braking control unit 10 outputs adjustment information that adjusts the distribution of the braking force for the four wheels based on the input brake assist command and the left-right differential pressure command, and the wheel cylinder (W / C) of each wheel. To control the hydraulic pressure (brake hydraulic pressure).

  In other words, when the left and right braking force distribution control intervenes during the brake assist control, the braking control unit 10 determines the pressure of the wheel cylinders of the left and right braking force distribution non-control wheels that are not controlled by the left and right braking force distribution control. The brake assist control is terminated so as to return to the driver brake pressure generated by the brake operation.

  FIG. 2 is an explanatory diagram of a hydraulic circuit having a valve that is brake-controlled by the brake control unit of FIG. As shown in FIG. 2, the hydraulic circuit 18 includes an inlet valve 19 and an outlet valve 20 connected to the left front wheel side wheel cylinder (W / C · FL) on the primary (P) side of the master cylinder (M / C). And an inlet valve 21 and an outlet valve 22 connected to the right rear wheel side wheel cylinder (W / C · RR).

The hydraulic circuit 18 includes an inlet valve 23 and an outlet valve 24 connected to the right front wheel side wheel cylinder (W / C / FR) on the secondary (S) side of the master cylinder (M / C), and the left rear wheel side. An inlet valve 25 and an outlet valve 26 connected to the wheel cylinder (W / C · RL) are provided.
Normally-open solenoids are used for the inlet valves 19, 21, 23, 25, and normally-closed solenoids are used for the outlet valves 20, 22, 24, 26.

  In this hydraulic circuit 18, a case will be described in which brake assist control intervenes and lane departure prevention (left / right braking force distribution) control intervenes and, for example, right system wheel pressure increase control is input. When the driver operates the brake operator (brake pedal), the brake assist control by the brake assist control unit 11 intervenes, and further, the LDP control unit 12 controls one side of the left and right wheels, that is, the right front wheel side. When the control for increasing the pressure of the wheel cylinder (W / C · FR) intervenes, the left and right braking force distribution non-control wheels, that is, the wheel valve (W / C · FL) on the left front wheel side (SOL / V · IN ( FL)) 19 is closed, and the inlet valve 19 is opened and closed in accordance with the brake assist control amount to increase the pressure.

  At this time, when the pressure increasing control for the wheel on one side intervenes, the brake control unit 10 interrupts the brake assist control, and is a wheel cylinder (W / W on the left front wheel side, for example, which is a left / right braking force distribution non-control wheel). C · FL) closes the inlet valve 19 on the left front wheel side in order to maintain the hydraulic pressure at the time when the pressure increase control for the wheel on one side is interrupted. Thereafter, when the pressure increase control for the wheel on one side is finished and the wheel cylinder pressures on the left and right sides become the same, the closed inlet valve 19 on the left front wheel side is opened, and the brake assist control is started again.

In this way, the brake control unit 10 performs control to interrupt the brake assist control and close the inlet valve 19 to open and close the inlet valve 19, that is, to turn the inlet valve 19 on and off, thereby reducing the hydraulic pressure. When the pressure on the downstream side of the passage (brake hydraulic pressure passage) is increased, it is possible to prevent the drive sound of the inlet valve 19 and the pulsation associated with the movement of the working fluid when the valve is opened and closed. At the same time, pedal vibration is not generated.
Next, a description will be given of the control process of the braking control unit 10 when the driver operates the brake operator (brake pedal) and the brake assist control intervenes and the left and right braking force distribution control intervenes.

  FIG. 3 is a flowchart showing a flow of control processing by the braking control unit of FIG. As shown in FIG. 3, when starting the control process by the brake control unit 10, it is first determined whether or not the brake assist control (R & B-UP control) is intervening (step S101). As a result of the determination, if the brake assist control is intervening (Yes), it is determined whether or not LDP control (left / right braking force distribution control) is started (step S102), while the brake assist control is not intervening. If (No), the process returns to step S101 to repeat the determination.

If the result of determination in step S102 is that the operation of LDP control has started (Yes), it is determined whether or not the driver's braking force (braking force) is constant (step S103), while the operation of LDP control is started. If not (No), the process returns to step S101 to repeat the determination.
If the result of determination in step S103 is that the driver's braking force is constant (Yes), the inlet valve (IN valve) of the LDP non-control wheels (left and right braking force distribution non-control wheels) is closed (step S104), If the driver's braking force is not constant (No), the target pressure of the non-LDP wheels is made to follow the target pressure for brake assist control (step S105), and then the process returns to step S101 and the determination is repeated.

After closing the IN valve of the LDP non-control wheels in step S104, the brake assist control command value is latched (step S106), and then whether or not LDP control is finished, that is, whether the left and right wheels are at the same pressure. Is determined (step S107).
If the result of determination in step S107 is that LDP control has not ended (No), the process returns to step S107 and the determination is repeated. On the other hand, if LDP control has ended (Yes), the IN valve of the non-LDP control wheel is turned off. Open (step S108).

After opening the IN valve of the LDP non-control wheel, it is determined whether or not the driver's braking force is constant (step S109). If the result of determination is that the driver's braking force is constant (Yes), brake assist control is resumed (step S110), and then the process returns to step S101 to repeat the determination. On the other hand, as a result of the determination, if the driver's braking force is not constant (No), the target pressure value of each wheel is made to follow the target pressure value of the brake assist control (step S111), and then the process returns to step S101 for determination. repeat.
Next, a change in the downstream pressure of the hydraulic pressure path by the brake assist control in the control process by the braking control unit in FIG. 1 will be described.

  FIG. 4 is a graph showing each input value that is a precondition for performing the control process by the brake control unit of FIG. 1, (a) is an explanatory diagram of the driver brake, and (b) is the downstream side of the hydraulic pressure path by the brake assist control. Explanatory drawing about pressure, (c) is explanatory drawing about the command value of LDP control. FIG. 5 is a graph showing the ideal output in each input state shown in FIG. 4, (a) is an explanatory diagram of the wheel cylinder pressure of the right wheel, and (b) is an explanatory diagram of the wheel cylinder pressure of the left wheel. 6 is a graph showing the actual output in each input state shown in FIG. 4, where (a) is an explanatory diagram of the wheel cylinder pressure of the right wheel, and (b) is an explanatory diagram of the wheel cylinder pressure of the left wheel.

As shown in FIG. 4, when the driver performs a brake operation (driver braking) and a brake pedal force is input (see (a)), brake assist control (R-UP control and B-UP control) intervenes. A brake assist control process is performed (see (b)), and further, an LDP command value for pressure increase is input through the LDP control (see (c)).
At this time, as shown in FIG. 5, the wheel cylinder in the case where the control distribution is equally performed on the right wheel (see (a)) as the control wheel and the left wheel (see (b)) as the non-control wheel. In fact, as shown in FIG. 6, when an LDP command value is input (see (a)), pedal vibrations S and the like are generated along with an unpleasant sound due to the on / off control of the IN valve, as shown in FIG. (See (b)).

Therefore, a braking control process by the braking control unit 10 is performed.
FIG. 7 is a graph showing a change in wheel cylinder pressure in the control process (part 1) by the braking control unit in FIG. 1, (a) is an explanatory diagram of the right wheel as a control wheel, and (b) is a non-control wheel. It is explanatory drawing of a certain left wheel. As shown in FIG. 7, when the driver operates the brake operator (brake pedal), the brake assist control by the brake assist control unit 11 intervenes, and further, for example, the LDP control unit 12 When the control for increasing the pressure of the wheel cylinder (W / C · FR) intervenes, the brake control system 10 ends the brake assist control during the LDP control (see (a) and (b)).

As a result, the left wheel (LH), which is a non-control wheel, does not increase in pressure when the brake assist control is completed, so that there is a change in vehicle behavior, vibration noise, tremor of the brake pedal, etc. caused by the on / off control of the IN valve. Does not occur.
(Second Embodiment)
FIG. 8 is a graph showing a change in wheel cylinder pressure in the control process (part 2) by the braking control unit in FIG. 1, (a) is an explanatory diagram of the right wheel as a control wheel, and (b) is a non-control wheel. It is explanatory drawing of a certain left wheel.

  As shown in FIG. 8, when the driver operates a brake operator (brake pedal), brake assist control (R-UP control and B-UP control) by the brake assist control unit 11 intervenes, and further, LDP For example, when control for increasing the pressure of the wheel cylinder (W / C / FR) on the right front wheel side is performed by the control unit 12, the brake control unit 10 ends the brake assist control during LDP control (see (a)). ) And the LDP non-control wheels maintain the hydraulic pressure at the time of pressure increase control intervention by LDP control until the brake is turned off. Both the LDP control wheels and the LDP non-control wheels have the same pressure, that is, the pressure difference between the left and right wheels When it disappears, it shifts to the brake operation by the driver (see (b)).

The configuration and operation of the other braking control units are the same as the configuration and operation of the braking control unit in the first embodiment.
As a result, the left wheel (LH), which is an LDP non-control wheel, retains the hydraulic pressure up to that point and does not decrease when the brake assist control is completed. Therefore, the behavior change of the vehicle caused by the ON / OFF control of the IN valve occurs. No vibration noise or brake pedal tremor.
That is, in the control process for ending the brake assist control during the LDP control in the first embodiment, since the pressure reduction by the outlet valve (OUT valve) is accompanied, the valve sound at the time of pressure reduction, the sound vibration due to the pulsation, the pedal vibration Although it is impossible to cope with the occurrence, pressure reduction by the OUT valve is not performed in the control processing in the second embodiment.

(Third embodiment)
FIG. 9 is a graph showing a change in wheel cylinder pressure in the control process (part 3) by the braking control unit in FIG. 1, (a) is an explanatory view of the right wheel as a control wheel, and (b) is a non-control wheel. It is explanatory drawing of a certain left wheel.

  As shown in FIG. 9, when the driver operates a brake operator (brake pedal), brake assist control (R-UP control and B-UP control) by the brake assist control unit 11 intervenes, and further, LDP For example, when control for increasing the pressure of the wheel cylinder (W / C / FR) on the right front wheel side is performed by the control unit 12, the brake control system 10 interrupts the brake assist control during LDP control and reduces the hydraulic pressure. At the same time (see (a)), the LDP non-control wheel holds the hydraulic pressure during the pressure increase control intervention by the LDP control until the brake is turned off (see (b)).

The configuration and operation of the other braking control units are the same as the configuration and operation of the braking control unit in the first embodiment.
As a result, the left wheel (LH), which is a non-control wheel, retains the hydraulic pressure and does not depressurize when the brake assist control is completed. Therefore, the vehicle behavior change, vibration noise, There is no trembling of the brake pedal.
In other words, after the brake assist control is interrupted by the LDP control intervention, the previous hydraulic pressure is maintained until the brake is turned off, thereby improving the driver's feeling that “the deceleration is lost even though the LDP control has been completed”. can do.

(Fourth embodiment)
FIG. 10 is a graph showing a change in wheel cylinder pressure in the control process (part 4) by the braking control unit in FIG. 1, (a) is an explanatory diagram of the right wheel as a control wheel, and (b) is a non-control wheel. It is explanatory drawing of a certain left wheel.

  As shown in FIG. 10, when the driver operates a brake operator (brake pedal), brake assist control (R-UP control and B-UP control) by the brake assist control unit 11 intervenes, and further, LDP For example, when control for increasing the pressure of the wheel cylinder (W / C · FR) on the right front wheel side is performed by the control unit 12, the brake control unit 10 interrupts the brake assist control during LDP control (see (a)). In addition, the LDP non-control wheels maintain the hydraulic pressure at the time of the pressure increase control intervention by the LDP control until the brake is turned off, and after the LDP control is finished, the brake assist control is resumed from the hydraulic pressure at the time when the brake assist control is interrupted (( b)).

The configuration and operation of the other braking control units are the same as the configuration and operation of the braking control unit in the first embodiment.
As a result, the left wheel (LH), which is a non-control wheel, maintains the hydraulic pressure and continues the brake assist control even after the end of the LDP control. Therefore, the vehicle behavior change caused by the on / off control of the IN valve In addition to the fact that no vibration noise or vibration of the brake pedal occurs, it is possible to obtain an effect of improving the feeling during driver braking by brake assist control.

  In the braking control system according to the present invention, a storage device is connected to a programmed main control unit (CPU) that comprehensively controls the entire system, and the CPU defines the control program and the various processing procedures described above. It has an internal memory for storing programs and required data, and the various means described above are realized by these programs.

It is a block diagram which shows the structure of the braking control system which concerns on 1st Embodiment of this invention. It is explanatory drawing of the hydraulic circuit which has a valve | bulb controlled by the braking control part of FIG. It is a flowchart which shows the flow of the control processing by the brake control part of FIG. FIG. 1 is a graph showing each input value that is a precondition for performing the control process by the braking control unit in FIG. 1, (a) is an explanatory diagram for a driver brake, and (b) is an explanation for a hydraulic pressure path downstream side pressure by brake assist control. FIG. 4C is an explanatory diagram of LDP control command values. The ideal output in each input state shown in FIG. 4 is shown by a graph, (a) is an explanatory diagram of the wheel cylinder pressure of the right wheel, and (b) is an explanatory diagram of the wheel cylinder pressure of the left wheel. The actual output in each input state shown in FIG. 4 is shown by a graph, (a) is an explanatory diagram of the wheel cylinder pressure of the right wheel, and (b) is an explanatory diagram of the wheel cylinder pressure of the left wheel. FIG. 1 is a graph showing a change in wheel cylinder pressure in the control process (part 1) by the braking control unit in FIG. 1, (a) is an explanatory diagram of a right wheel that is a control wheel, and (b) is a left wheel that is a non-control wheel. It is explanatory drawing. FIG. 1 is a graph showing a change in wheel cylinder pressure in the control process (part 2) by the braking control unit in FIG. 1, (a) is an explanatory diagram of a right wheel that is a control wheel, and (b) is a left wheel that is a non-control wheel. It is explanatory drawing. FIG. 1 is a graph showing a change in wheel cylinder pressure in the control process (part 3) by the braking control unit in FIG. 1, (a) is an explanatory diagram of a right wheel as a control wheel, and (b) is a left wheel as a non-control wheel. It is explanatory drawing. FIG. 1 is a graph showing a change in wheel cylinder pressure in the control process (part 4) by the braking control unit in FIG. 1, (a) is an explanatory diagram of a right wheel as a control wheel, and (b) is a left wheel as a non-control wheel. It is explanatory drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Braking control part 11 Brake assist control part 11a Brake assist command control part 12 LDP control part 12a Left-right differential pressure command generation part 13 Four-wheel braking force distribution 1st calculating part 14 4-wheel braking force distribution 2nd calculating part 15 4 wheel control Power distribution adjusting unit 16 Hydraulic servo unit 17 Driver brake unit 18 Hydraulic circuit 19, 21, 23, 25 Inlet valve 20, 22, 24, 26 Outlet valve

Claims (5)

A brake assist control unit for performing brake assist control for assisting the brake operation by generating a braking force larger than the braking force generated by the driver's brake operation;
Left and right braking force distribution control unit for performing left and right braking force distribution control for distributing braking force to the left and right traveling wheels in order to prevent deviation of the traveling wheels from the lane;
If the left and right braking force distribution control intervenes during the intervention of the brake assist control, the pressure of the wheel cylinders of the left and right braking force distribution non-control wheels that are not controlled by the left and right braking force distribution control are caused by the brake operation of the driver. And a braking control unit for terminating the brake assist control so as to return to the generated driver brake pressure. The braking control unit
At the end of the brake assist control due to the intervention of the left and right braking force distribution control, the left and right braking force distribution non-control wheels hold the brake fluid pressure at the time of the left and right braking force distribution control intervention until the end of the brake operation of the driver, 2. The braking control system according to claim 1, wherein when the left and right wheels are at the same pressure due to the end of the left and right braking force distribution control, the left and right wheels are controlled to shift to the brake operation state of the driver. The braking control unit
The brake assist control is interrupted by the left / right braking force distribution control intervention, and control is performed to maintain the brake fluid pressure at the time of the previous left / right braking force distribution control intervention until the driver's braking operation is completed. The braking control system described. The braking control unit
The brake assist control is interrupted by the left / right braking force distribution control intervention, and after the front left / right braking force distribution control ends, the brake assist control is resumed from the brake fluid pressure at the time of the interruption of the brake assist control. The braking control system according to claim 1. The braking control unit
A four-wheel braking force distribution first calculation unit that outputs four-wheel braking force distribution information based on the input brake assist control command;
A four-wheel braking force distribution second calculation unit that outputs four-wheel braking force distribution information based on the input left and right braking force distribution control command;
A four-wheel braking force distribution adjustment unit that outputs a four-wheel braking force distribution adjustment command based on the four-wheel braking force distribution information from the four-wheel braking force distribution first calculation unit and the four-wheel braking force distribution second calculation unit; The braking control system according to any one of claims 1 to 4, further comprising:

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