JPH08230648A - Brake hydraulic controller - Google Patents

Abstract

PURPOSE: To correctly control w/c pressure of a brake hydraulic controller without using any expensive pressure sensor by estimating the master pressure and w/c pressure by means of TCS, etc., for making the pressure of an external hydraulic pressure source as the master pressure and increasing w/c pressure. CONSTITUTION: A brake hydraulic controller is provided with, for instance, an accumulator (ACC) 6 for obtaining the master pressure of w/c pressure, a solenoid valve 2 for calculating w/c pressure by means of TCS by making pressure increase instruction or pressure decreasing instruction for a prescribed period of time so as to regulate the w/c pressure to the set target w/c pressure, and a pump 4 for regulating the ACC pressure to a required pressure. A controller 8 calculates an estimated ACC pressure, and an estimated w/c pressure in order for every control period so as to control the w/c pressure. The estimation of ACC pressure becomes correct if it is practiced by a variation quantity of the estimated w/c pressure and a pump driving stop signal. w/c pressure after the pressure increasing instruction for a set period of time is estimated on the basis of a pressure difference between the estimated ACC pressure and the estimated w/c pressure prior to pressure increase. Also, a pressure increasing instruction time required for regulating the w/c pressure to the target w/c pressure is calculated on the basis of the pressure difference between the estimated ACC pressure and the estimated w/c pressure prior to pressure increase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake hydraulic pressure control device.

[0002]

2. Description of the Related Art As a technique for controlling a brake fluid pressure, the present applicant has previously proposed a traction control system (TCS) which prevents wheel driving slips by wheel braking (Japanese Patent Laid-Open No. Hei. 85051 (reference 1)). This is for estimating the hydraulic pressure of the wheel cylinder (w / c) of the wheel to be controlled and increasing the pressure when performing necessary pressure increase / decrease control of the wheel cylinder pressure (hereinafter also abbreviated as w / c pressure). It is intended to measure the pressure time and the pressure reduction time and estimate the w / c pressure based on the deviation.

[0003]

However, in order to make a more accurate estimation with respect to the above, further improvements can be made in consideration of the following points, for example. When w / c is increased by an accumulator (ACC) of an external hydraulic pressure source, the amount of increase in w / c pressure is equal to the accumulator pressure (hereinafter, A
CC pressure) and w / c pressure before pressure increase. Therefore, when controlling the w / c pressure to the control target w / c pressure, the w / c pressure may simply be estimated based on the deviation by measuring the pressure increase time and the pressure decrease time as described above. The estimation accuracy may decrease and the control accuracy may decrease.

When the control accuracy of the w / c pressure is lowered, a target w / c pressure required to suppress the slip of the driving wheels is calculated, and a traction control for controlling the w / c pressure is calculated. For the device, w / c
Due to insufficient pressure or excessive pressure, slippage of the drive wheels cannot be reliably suppressed, or the acceleration of the vehicle is reduced.

An apparatus for increasing w / c by an external hydraulic pressure source (other than the master cylinder pressure) sets, for example, a target vehicle speed and decelerates the driving force during acceleration so that the actual vehicle speed becomes the target vehicle speed. Sometimes, it can be incorporated as a vehicle follow-up running control system for controlling the braking force. However, in such a follow-up running control device, the target vehicle speed w required for the actual vehicle speed to reach the target vehicle speed during deceleration. When calculating the / c pressure and controlling the w / c pressure, it is assumed that the actual w / c pressure is not controlled according to the target w / c pressure because the estimation accuracy is not sufficient and the control accuracy is poor. , The vehicle speed cannot be controlled according to the target vehicle speed.

The present invention has been improved on the basis of the above consideration to improve the estimation accuracy in the hydraulic pressure control when controlling the braking hydraulic pressure while estimating the wheel cylinder pressure, thereby improving the control accuracy and increasing the cost. An object of the present invention is to provide a braking fluid pressure control device that can accurately control a wheel cylinder pressure to a target fluid pressure without using a pressure sensor.

[0007]

According to the present invention, the following braking hydraulic pressure control device is provided. That is, a braking hydraulic pressure control device capable of increasing the pressure of a wheel cylinder of a wheel to be controlled of a vehicle by an external hydraulic pressure source, wherein a target wheel of the wheel cylinder whose source pressure is the supply pressure from the external hydraulic pressure source. Target hydraulic pressure calculating means for calculating the cylinder pressure, estimating means for estimating the supply pressure from the external hydraulic pressure source, and adjusting the wheel cylinder pressure to the target wheel cylinder pressure by issuing a pressure increase command or pressure decrease command for a predetermined time. And a wheel cylinder pressure estimation means including means for estimating the wheel cylinder pressure after pressure increase for a predetermined time based on the estimated value of the original pressure by the estimation means and the estimated wheel cylinder pressure value. , The necessary value for adjusting the wheel cylinder pressure to the target wheel cylinder pressure based on the estimated value of the original pressure, the estimated wheel cylinder pressure value, and the target wheel cylinder pressure value. Comprising means for calculating the increasing pressure command time for solenoid valves, a brake fluid pressure control device, characterized in that it comprises a control command operation unit.

Further, in the above, the external hydraulic pressure source includes an accumulator for obtaining the original pressure of the wheel cylinder pressure, and has a pump mechanism for adjusting the accumulator pressure to a required pressure, and the pump thereof. And a means for estimating the source pressure, wherein the means for estimating the source pressure is the change in the estimated wheel cylinder pressure or the previous value and the current value of the estimated wheel cylinder pressure, and the drive stop information of the pump detected by the detection means. The braking fluid pressure control device is a means for estimating the accumulator pressure based on the above.

Further, the accumulator pressure is estimated by the source pressure estimating means, and the wheel cylinder estimating means is
Based on the pressure difference between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase, the means for estimating the wheel cylinder pressure after the pressure increase command for a predetermined time and calculating the pressure increase command time is increased by the estimated accumulator pressure. Based on the pressure difference between the pre-estimated wheel cylinder pressure and the target wheel cylinder pressure, the pressure increase time necessary for adjusting the wheel cylinder pressure is calculated, and the braking hydraulic pressure control device is characterized in advance. The relationship between the amount of decrease in the accumulator pressure with respect to the amount of increase in the wheel cylinder pressure, the relationship between the amount of increase in the accumulator pressure with respect to the driving time of the pump, which is obtained in advance, and the difference in pressure between the accumulator pressure and the wheel cylinder pressure that is obtained in advance It has a storage means for storing the relationship between the pressure increase time and the amount of increase in the wheel cylinder pressure, and by the relationship stored in the storage means, Determine the amount of pressure reduction of the constant wheel cylinder pressure previous value and the estimated wheel cylinder pressure current value from the accumulator pressure, seeking pressure increase amount of the accumulator pressure relative to the pump driving time, to estimate the current value of the accumulator pressure,
The differential pressure is calculated from the estimated accumulator pressure present value and the estimated wheel cylinder pressure present value, and the wheel cylinder pressure increase amount for a predetermined pressure increase time is obtained from the relationship stored in the storage means. The braking fluid pressure control device is characterized in that accumulator pressure estimation and wheel cylinder pressure estimation are performed so as to estimate the wheel cylinder pressure.

Further, the target wheel cylinder pressure is the target wheel cylinder pressure of the drive wheel during the drive slip control in the traction control, or the target wheel cylinder pressure of the control target wheel for controlling the braking force during the deceleration control in the following travel control. Either the target wheel cylinder pressure or the target wheel cylinder pressure of the control target wheel when controlling the wheel cylinder pressures of the left and right wheels independently in vehicle behavior control, or two or more of them The braking fluid pressure control device is characterized by:

[0011]

With the above configuration, even when the wheel cylinder pressure is controlled to be increased by the external hydraulic pressure source, the pressure of the external hydraulic pressure source, which is the source pressure of the wheel cylinder pressure, is also estimated to estimate the wheel cylinder pressure. The command time can be calculated, and changes in the pressure of the external hydraulic pressure source during pressure increase control can be reflected appropriately in the control, and estimation that also takes into consideration the pressure difference between the original pressure and the wheel cylinder pressure. It is possible to control, the estimation accuracy is lower than that when the original pressure is not observed, and this can be easily realized without adding an expensive pressure sensor. It will be possible to control the wheel cylinder pressure in more detail according to the target value and to improve the control accuracy.

By estimating the source pressure and estimating and controlling the wheel cylinder pressure, the wheel cylinder can be accurately controlled and the control accuracy can be improved. Therefore, in the traction control device, when the drive wheels slip, The wheel cylinder pressure does not become insufficient or excessive, slip can be reliably suppressed, and acceleration performance does not deteriorate. Further, the follow-up running control device can control the actual vehicle speed according to the target vehicle speed. Further, the left and right wheel cylinder pressures can be independently controlled to be applied to the case of controlling the behavior of the vehicle while turning or going straight, and it can be similarly effective. When controlling the behavior of such a vehicle, if the left and right wheel cylinders do not meet the target value due to poor control accuracy of the wheel cylinder pressure (for example, one wheel cylinder pressure is higher than the target value and the other wheel cylinder pressure is higher than the target value). If the cylinder pressure is lower than the target value),
Since an unintentional moment is generated in the vehicle and the behavior of the vehicle cannot be controlled as intended, the wheel cylinder pressure can be controlled according to the present invention according to the target value. It is possible to control the behavior of the vehicle as intended without generating an unintended moment.

The external hydraulic pressure source includes an accumulator for obtaining the original pressure of the wheel cylinder pressure, has a pump mechanism for adjusting the accumulator pressure to a required pressure, and stops the driving of the pump. The source pressure estimating means includes a detecting means for detecting, based on a change in the estimated wheel cylinder pressure or a previous value and a current value of the estimated wheel cylinder pressure, and the drive stop information of the pump detected by the detecting means. As a means for estimating the pressure, the invention can be implemented and likewise makes it possible to achieve the above. In this case, the accumulator pressure, which is the original pressure, is estimated by considering that the accumulator pressure in the accumulator decreases as the wheel cylinder pressure increases, while the accumulator pressure increases as the pump is driven. Accurate estimation of the accumulator pressure can be made possible.

Further, the source pressure estimating means estimates the accumulator pressure, and the wheel cylinder estimating means determines the wheel after the pressure increase command for a predetermined time based on the pressure difference between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase. The means for estimating the cylinder pressure and calculating the pressure increase command time is necessary for adjusting the wheel cylinder pressure to the target wheel cylinder pressure based on the differential pressure between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase. The present invention can be implemented by calculating the pressure boosting time, and also makes it possible to realize the above. In this case, the wheel cylinder estimation and the pressure increase command time calculation can be performed based on the estimated accumulator pressure obtained by the above estimation. Therefore, the estimation of the wheel cylinder pressure after the pressure increase command for the predetermined time according to the pressure difference between the estimated accumulator pressure and the estimated wheel cylinder pressure before the pressure increase can be made more accurate, and the necessary wheel cylinder pressure can be obtained. Even if the relationship between the pressure increase time and the pressure increase time differs depending on the differential pressure between the accumulator pressure and the wheel cylinder pressure, which is the original pressure, it can be handled appropriately, and the differential pressure can be calculated by estimating the accumulator pressure and the wheel cylinder. By calculating the pressure increase time for the pressure increase amount, it is possible to accurately calculate the time for increasing the required pressure increase amount, and even in that case, use the estimated accumulator pressure value obtained as the above accurate value. The pressure increase command time can be calculated more accurately.

Further, the relationship between the previously determined increase amount of the wheel cylinder pressure and the reduced pressure amount of the accumulator pressure, the previously determined relationship between the pump driving time and the increased amount of the accumulator pressure, and the previously determined accumulator pressure. And the wheel cylinder pressure difference, the storage means stores the relationship between the pressure increase time and the wheel cylinder pressure increase amount, and the estimated wheel cylinder pressure previous value is stored in the storage means. Estimated wheel cylinder pressure This time, the amount of pressure reduction of accumulator pressure is calculated, the amount of increase in accumulator pressure with respect to the pump drive time is calculated, and the current value of accumulator pressure is estimated, and this estimated accumulator pressure current value and estimated wheel cylinder pressure this time The differential pressure is calculated from the value and the wheel for a predetermined pressure increasing time is calculated from the relationship stored in the storage means. The present invention can be implemented as a configuration in which the accumulator pressure estimation and the wheel cylinder pressure estimation are performed so as to obtain the cylinder pressure increase amount and estimate the wheel cylinder pressure after the pressure increase, and it is possible to realize the above in the same manner. Let's train. In this case, in the preferred example, depending on the system to be applied, accumulators, pumps, etc. to be used, related data are obtained in advance and stored in the memory of the controller, and based on this, each estimation can be easily and accurately performed. It can be carried out. In estimating accumulator pressure,
Accumulator can be accurately estimated by obtaining the relation between the wheel cylinder pressure increase amount and the accumulator pressure reduction amount in advance, and the relation between the accumulator pressure increase amount and the pump drive time can be obtained in advance. Accumulator pressure can be accurately estimated. The relationship between the pressure increase amount of the wheel cylinder pressure and the pressure increase time depends on the pressure difference between the accumulator pressure, which is the original pressure, and the wheel cylinder pressure.
The wheel cylinder after the pressure increase can be accurately estimated by estimating the accumulator pressure and the wheel cylinder pressure, calculating the pressure difference between them, and obtaining the pressure increase amount with respect to the pressure increase time.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing the configuration of an embodiment of the device of the present invention. Although the drawings show the necessary elements and components of the braking hydraulic pressure control system according to the present embodiment, which relate to one wheel of the vehicle, the other control target wheels of the vehicle have the same configuration. Things exist.

In the figure, 1 indicates the wheel cylinder (w / c) of the wheel 10, and the wheel cylinder pressure (w / c).
Pressure) is controlled by the following hydraulic control system (in the figure,
Solid lines indicate hydraulic piping, dotted lines indicate signal lines). In this example, the hydraulic circuit is provided with a configuration for increasing the pressure of the wheel cylinders by an external hydraulic pressure source (other than the master cylinder pressure), and here, the wheel cylinder 1 of the wheel 10, the solenoid valve 2, the reservoir tank 3 are provided. , A pump 4, and an accumulator (ACC) 6, which are connected by piping as shown in the drawing.

The solenoid valve 2 is interposed between the hydraulic pressure source for obtaining the original pressure of the w / c pressure and the wheel cylinder 1 so that the pressure can be adjusted by increasing / decreasing the w / c pressure according to the increasing / decreasing pressure command. It is a solenoid valve. Here, a 3-port, 3-position switching solenoid valve that switches between increasing pressure, holding, and reducing pressure is used. The solenoid valve 2 has a port for the hydraulic passage on the side of the wheel cylinder 1 and a port for the hydraulic passage on the side of the accumulator 7 that stores the hydraulic pressure to be sent to the wheel cylinder 1 when the pressure is increased in the case of the pressure increase control. The switching control is performed so that the liquid path to the reservoir tank 3 is blocked while the liquid path to the reservoir tank 3 is blocked. Further, when switching to the holding position, the connection should be cut off from both the accumulator 6 side and the reservoir tank 3 side. Further, in the case of the pressure reduction control, the port of the fluid passage on the wheel cylinder 1 side is Switching control is performed so as to connect this to the port of the liquid passage on the reservoir tank 3 side and to shut off the connection with the liquid passage on the accumulator 6 side.

The wheel cylinder 1 is a reservoir tank 3 for storing the brake fluid from the wheel cylinder 1 when the pressure is reduced.
The brake fluid in the wheel cylinder is drained. The liquid path from the reservoir tank 3 is further connected to the accumulator 6 via the pump 4.

The pump 4 has an accumulator pressure (ACC
Pressure) to be a pump (accumulator pump) driven by a motor capable of adjusting the pressure to a predetermined pressure, and driving and stopping the driving of the pump driving motor 5 and accordingly the pump 4
When the pump is driven in response to the driving and stopping of the above, the brake fluid accumulated in the reservoir tank 3 due to the above pressure reduction is sent to the accumulator 6 to accumulate the fluid pressure. Then, here, a pressure-responsive switch 7 is arranged in the liquid path of the accumulator 6, and the switch has, for example, a pressure (ACC pressure) in the accumulator 6 that is a first predetermined value (for example, 120 kgf / cm ² ) or less, it is ON, and a second predetermined value (for example, 150 kgf / cm) larger than the first predetermined value.
² ) If it is above, it is output as OFF and used as the pressure switch 7 for controlling the pump motor 5.

In the above apparatus, the external hydraulic pressure source is configured to include the accumulator 6, and the ACC pressure thereof is w / when the pressure of the wheel cylinder 1 is increased by the control of the solenoid valve 2.
The pressure is reduced by increasing the pressure c, while the pressure is increased by driving the pump 5 when the motor 7 drives the pump.

The control of the solenoid valve 2 is performed by a controller 8 for controlling the system. As shown in the figure, the solenoid valve 2 is connected to the controller 8 by a control signal line, and the controller 8 and the motor 5 are connected. There is. The controller 8 is configured to include a microcomputer including an input / output unit, a calculation processing unit, and a storage unit that stores a program executed by the calculation processing unit, a calculation result, and the like.

In the w / c pressure control of the wheel cylinder 1, the controller 8 determines the target hydraulic pressure required for control based on the required input information in accordance with the target wheel cylinder pressure calculation calculation program stored in the storage unit in advance. It is calculated, set, and w / c pressure control is executed. Here, regarding the calculation of the target value of the w / c pressure, for example, in the case of a traction control system (TCS), with respect to the slip of the driving wheels, the target w / c required to suppress the slip is suppressed.
This can be done by calculating the c pressure. Further, for example, when the vehicle automatic follow-up system is mounted instead of or together with this, the actual vehicle speed is set to be the same as that of the preceding vehicle in order to control the vehicle speed during traveling by controlling the braking force during the deceleration control. The target w / c pressure required to reach the target vehicle speed set by the relationship is calculated.

Further, the controller 8 uses a pressure sensor in controlling the solenoid valve 2 so as to regulate the w / c pressure to such a set target w / c pressure by issuing a pressure increase command or a pressure decrease command for a predetermined time. Instead, the w / c pressure is estimated and this is performed. At this time, basically, information regarding the driving and stopping of the accumulator pump 4 is used as input information, and w
AC from the amount of change in / c pressure and the drive stop signal of the pump 4.
The control is executed while also estimating the C pressure. Controller 8
Therefore, in addition to the target w / c pressure calculation subroutine program described above, the storage unit of
A control program including a c-pressure estimation process is also stored in advance, and the arithmetic processing unit executes it.

In this case, preferably, in the pressure increase control of the w / c pressure, after the pressure increase command for a predetermined time, based on the pressure difference between the estimated ACC pressure obtained by the above estimation and the estimated w / c pressure before the pressure increase. Estimate w / c pressure of Further, preferably, the pressure increase command time required for adjusting the w / c pressure to the target w / c pressure is calculated based on the pressure difference between the estimated ACC pressure and the estimated w / c pressure before pressure increase.

FIG. 2 is a block diagram showing an example of the outline of the function of the embodiment system shown in FIG. 1 for controlling the w / c pressure as described above. As shown in FIG. Means a for calculating pressure, means b for detecting drive and stop of the accumulator pump, accumulator pressure (ACC pressure)
From the estimating means f, the wheel cylinder pressure estimating means g for estimating the w / c pressure after a predetermined time from the estimated ACC pressure and the estimated w / c pressure, the estimated ACC pressure, the estimated w / c pressure and the target w / c pressure,
It is provided with a means h for calculating a pressure increase time required to adjust the estimated w / c pressure to a target w / c pressure, and a braking force control means j. Here, in the present embodiment, the braking force control means j
Is configured to include a part of the controller 8 and the hydraulic circuit of FIG. 1 including the solenoid valve 2 that regulates the w / c pressure to the target pressure in response to the pressure increase / decrease command. The controller 8 also constitutes the target hydraulic pressure calculating means a, the detecting means b, the estimating means f and g, and the pressure increasing time calculating means h.

The target hydraulic pressure calculating means a is a braking hydraulic pressure required for its control, that is, a target w /
The accumulator pump drive stop detection means b functions as a means for calculating the c pressure, and the accumulator pump drive stop detection means b drives and stops the pump 5 that regulates the ACC pressure for obtaining the original pressure of the w / c pressure to a predetermined pressure. It functions as a detection means for detecting. In a preferred example, the accumulator pressure estimating means f
Is the estimated w / c pressure obtained by the wheel cylinder pressure estimation means g when the drive control of the solenoid valve 2 is performed while estimating the w / c pressure for each control cycle without using the wheel cylinder pressure sensor. From the previous value and the current value of, and the drive stop of the pump 5 detected by the detecting means b,
The current value of the ACC pressure can be estimated.
The estimated ACC pressure current value obtained by the estimation can be applied to the estimation by the wheel cylinder pressure estimation means g and the calculation by the pressure increase time calculation means h.

In this case, as for the estimation of the ACC pressure, more preferably, as described above, the accumulator 6 is used.
The ACC pressure at is reduced when the w / c pressure is increased, while the ACC pressure is increased by driving the pump.
Since the pressure is increased, w / w depends on the accumulator 6, pump 5, etc. used in the hydraulic circuit as shown in FIG.
This is performed in consideration of the relationship between the increased amount of the c pressure and the reduced amount of the ACC pressure and the relationship between the increased amount of the ACC pressure and the pump driving time. Regarding their relationship, w /
It is possible to obtain the relationship between the pressure increase amount of the c pressure and the pressure reduction amount of the ACC pressure and store the data in the memory of the storage unit of the controller 8.
It is possible to obtain the pressure increase amount of the ACC pressure with respect to the driving time of the CC pump and store the data in the memory of the storage unit of the controller 8.

More preferably, the estimation by the wheel cylinder pressure estimating means g is the accumulator pressure estimating means f.
By using the estimated value obtained by considering the relationship as described above in 1. and estimating the w / c pressure after the predetermined time increase from the estimated ACC pressure and the estimated w / c pressure,
It can be carried out. In this case, in the w / c pressure estimation, it is preferable to consider the relationship between the pressure increasing time and the pressure increasing amount which are different depending on the differential pressure between the ACC pressure and the w / c pressure, and therefore, Estimated ACC pressure current value and estimated w /
The differential pressure between the two is calculated using the c pressure current value, and the pressure increase amount corresponding to the pressure increase time is calculated according to the differential pressure, and the estimated w / c pressure current value and the calculated pressure increase are calculated. As a sum with the quantity value, the w / c pressure after the pressure increase can be estimated. Also in this case, the relationship between the pressure increasing time and the pressure increasing amount that differs depending on the pressure difference between the ACC pressure and the w / c pressure is obtained in advance, and the data is stored in the memory of the storage unit of the controller 8. The w / c pressure increase amount for a predetermined pressure increasing time can be obtained by using this.

The pressure increasing time calculating means h is configured to calculate the estimated ACC pressure, the estimated w / c pressure and the calculated target w / c of the target hydraulic pressure calculating means a.
The pressure increase time required to adjust the estimated w / c pressure to the target w / c pressure is calculated from these values. The pressure increase command corresponding to the pressure increase time thus calculated is the braking force control means j.
The solenoid valve 2 is controlled by this. Also in this case, it is preferable to consider that the relationship between the required pressure increase amount of the w / c pressure and the pressure increase time differs depending on the differential pressure between the ACC pressure that is the original pressure and the w / c pressure. The amount of pressure increase required to control the actual w / c pressure to the target value by obtaining the pressure increase time for the required amount of pressure increase according to the pressure difference between the current pressure value and the estimated w / c pressure current value. Only the time for increasing the pressure is calculated. The characteristic of the relationship between the pressure increasing time and the pressure increasing amount used in the wheel cylinder pressure estimating means g can be preferably used in the calculation of the pressure increasing time.

Regarding the current value of the w / c pressure applied in the estimation for each cycle, the current value of the w / c pressure is updated to the previous value, and the w / c pressure after pressure increase is updated to the current value. To do.
Thereby, the next estimated ACC pressure can be calculated. Furthermore,
The next estimated ACC pressure is updated to the current value, and the next estimated w / c pressure is calculated. In this way, the estimated ACC pressure,
The estimated w / c pressure is calculated. In this case, each estimating means f and g can be configured to include these updating functions.

3 to 5 are flowcharts of an example of a braking hydraulic pressure control program executed by the controller 8 and including the ACC pressure estimation, w / c pressure estimation, command time calculation and other processing. This program is repeatedly executed at regular intervals T. 6 to FIG.
FIG. 8 is a diagram for explaining the content of this control. The flow chart will be described below with reference to these drawings as well, but the following symbols used in the description mean the following matters and contents, respectively.

[0033]

[Table 1] p _wc ; Estimated w / c pressure (estimated wheel cylinder pressure) p _ACC ; Estimated ACC pressure (estimated accumulator pressure) Δp _wc ; Estimated value of w / c pressure increase / decrease amount Δp _ACC ⁺ ; ACC pressure increase the amount Delta] p _ACC ^-; ACC pressure decreasing amount Delta] p _ACC; decrease pressure of the accumulator pressure Delta] p _AW; estimated differential pressure between the ACC pressure and the estimated w / c pressure p ^*; target w / c pressure (target pressure) Delta] p _e; Deviation between the target w / c pressure and the estimated w / c pressure f ₁ ; Function for obtaining the reduced pressure amount of the ACC pressure from the increased amount of the w / c pressure f ₂ ; The differential pressure between the estimated ACC pressure and the estimated w / c pressure ,
From the deviation between the target w / c pressure and the estimated w / c pressure, the function f ₃ Request pressure increasing time; function f ₄ to obtain a pressure increase amount from the differential pressure and the pressure increase time and the estimated ACC pressure and the estimated w / c pressure Estimated w / c pressure, target w / c pressure and estimated w / c
Function for obtaining decompression time from deviation of c pressure f ₅ ; Function for obtaining decompression amount from estimated w / c pressure and decompression time

Further, in the following description, the subscript n-1 used in the subscript portion indicates the value at the previous sampling, n is the value at the present sampling, and n + 1 is the value at the next sampling.

Referring to FIGS. 3 to 5, in the case of this program example, the processing steps are steps 101 to 111,
It consists of steps 201 to 210, and the general role of each step is as follows. And
The next process is repeated at regular intervals. [1] In steps 101 to 107, the ACC pressure is estimated. [2] In step 108 to step 111, the target w /
The difference between the c pressure and the estimated w / c pressure is calculated to determine which of pressure increase, pressure hold, and pressure reduction calculations should be performed. Here, the target w / c pressure is
For example, it is calculated by a TCS system or an automatic follow-up system for the preceding vehicle. [3] In step 201, a holding operation is performed. [4] In steps 202 to 205, the calculation for increasing the pressure is performed. [5] In steps 206 to 208, the pressure reduction is calculated. [6] Step 209 is a w / c pressure estimation process,
In step 210, each estimated value is updated.

The sequence will be described in sequence according to the flow of the flowchart. First, in FIG.
/ C pressure current value p _WCn and estimated w / c pressure previous value p _WCn-1 are compared to determine whether the previous pressure increase or pressure reduction was performed. Here, the value p _WCn and the value p _WCn-1 are the values rewritten in the update processing of step 210 in the previous loop, and in step 101, the determination is performed by reading them. Step 1 according to the result of the above judgment
02 of treatment ^{_{(Δp ACC - = f 1 (}} p WCn,
p _WCn-1 )) or the processing of step 103 (Δp _ACC
^- = 0) is selected and the process proceeds to step 104.

[0037] went last time in the case of w / c the pressure increase in step 102, the pressure reduction amount Delta] p _ACC of aCC6 ^- computing the. Here, in this program example, the relationship between the pressure increase amount of the w / c pressure and the pressure reduction amount of the ACC pressure is obtained in advance, and the data is stored in the memory. Therefore, first, the relation is obtained in advance. _{Depending on the} relationship, w / c pressure previous value p _{WCn- 1}
And estimated w / c pressure current value p _WCn to ACC pressure reduction amount Δp
_ACC ^- the seek.

[0038] Specifically, a system used in this embodiment, for example, to increase pressure of the w / c pressure 50 kgf / cm ^2, the ACC pressure is assumed to have a relationship that is 1 kgf / cm ² under reduced pressure, In that case, the pressure reduction amount Δp _ACC ⁻ of the ACC pressure can be obtained based on the following equation.

## EQU1 ## Δp _ACC ^- =-(p _WCn- p _WCn-1 ) / 50 ・ ・ ・ 1 On the other hand, when the pressure was not increased but the last time the pressure was reduced by w / c (p _WCn = p _WCn- including the case of _1), since the reduced pressure of the ACC pressure is not performed, at step 103, Δp _{AC C} ^- = 0
And

In the case of increasing w / c pressure, ACC pressure is w / c
The pressure is reduced by increasing the pressure, but in this way, w / c
If the relationship between the pressure increase amount and the ACC pressure reduction amount is obtained in advance, the ACC pressure can be estimated in consideration of the reduced pressure, and accurate estimation can be performed.

Next, at step 104, the motor is turned on /
Captures OFF information and turns ON / OFF the pump motor 5.
Judge. That is, here, it is detected and monitored whether the ACC pump 6 is driven or stopped, and the answer is Yes according to the result of the determination.
If s, step 105 is selected. If No, step 106 is selected and the process proceeds to step 107. When the motor 5 is ON, that is, when the pump 6 is in a driving state, the pressure increase amount Δp _ACC ⁺ of the ACC pressure is calculated. Also in this case, in this program example, the amount of increase in the ACC pressure with respect to the drive time of the ACC pump 6 is obtained in advance and the data is stored in the memory. Therefore, in step 105,
From the drive time of the pump 6, A
Determine the amount of increase in CC pressure Δp _ACC ⁺ .

For example, in the system used in this embodiment,
When the pump motor 5 is ON, the ACC pressure has a relationship of increasing at a constant rate with respect to time. In such a case, a predetermined constant value is substituted for the ACC pressure increase amount Δp _ACC ^+. Therefore (Δp _{AC C} ⁺ = constant), the processing here can be achieved. On the other hand, when the pump motor 5 is off, the ACC pressure is not increased, so in step 106 A
The value 0 is substituted for the CC pressure increase amount Δp _ACC ⁺ , and the routine proceeds to step 107.

In this way, the ACC pressure is increased by the drive of the pump 6, so that the AC with respect to the pump drive time is increased.
By obtaining the relationship of the pressure increase amount of the C pressure in advance, the ACC pressure can be accurately estimated even when the ACC pump is driven.

As described above, the pressure reduction amount Δp of the ACC pressure is
_ACC ⁻ , and ACC pressure boost Δp _ACC ⁺
Estimate the current value of ACC pressure p _ACCn . That is, in the next step 107, the value Δp _ACC ⁺ and the value Δp _ACC ⁻ obtained in step 102 or 103 and step 105 or 106 are added to the ACC pressure previous value p _ACCn−1 based on the following equation. Then, the estimated ACC pressure current value p _ACCn is obtained.

[Number 2] _{p ACCn = p ACCn-1 +} Δp ACC + + Δp ACC - ··· 2 here, the value p _ACCn-1, the step 210 of the previous loop
Is the value rewritten in the updating process of 1. In step 107, it is read and applied to the above equation 2.

As described above, the ACC pressure as the pressure of the external hydraulic pressure source during the w / c pressure control can be estimated, and even if the ACC pressure is reduced by increasing the w / c pressure, Even if the pressure is increased by driving, an accurate estimated value can be obtained. The estimated ACC pressure value p _ACCn calculated by the processing of steps 101 to ₁₀₇ is the Δp _AW value (differential pressure value between the estimated ACC pressure and the estimated w / c pressure) calculated in step 203 (FIG. 5) described later. Used for processing.

Next, at step 108 (FIG. 4), the target w / c pressure p ^* is read. Regarding the target w / c pressure p ^* , as described above, in the present embodiment, the w / c pressure required for the target control is stored in the storage unit of the controller 8 in accordance with the TCS system or the like to be applied. It can be obtained by incorporating a program for a target w / c pressure calculation subroutine (not shown) for setting a target value and executing it. Therefore, in this case, since the target w / c pressure p ^* is calculated on the program side, in this step 108, the calculation result of the target w / c pressure value calculated at that time is calculated in this step. Capture each process.

[0046] Thus, in step 109, a target w / c pressure value p ^* and the estimated w / c pressure deviation Δp _e of the current value p _WCn read,

## _{EQU3 ## Obtained} by Δp _e = p ^* -p _WCn ... Then, the value Δp calculated by the above equation
_{Using e} , in the next steps 110 and 111, the deviation Δp _e
Whether the pressure increase, the pressure hold, or the pressure reduction is to be calculated is determined according to the sign of

Here, specifically, the determination as to whether Δp _e <−1 (step 110) and the determination as to whether Δp _e > 1 (step 111) are performed. Three
If the value Δp _e obtained in step is a range of Δp _e <−1 (the answer at step 110 is Yes), it is decompressed, and a value Δp _e > 1 (the answer at step 110 is No and the answer at step 111 is Yes). pressure increase, -1 ≦ Δp _e ≦ 1 range (the answer to step 110 is in No, and the answer to step 111 No)
If so, hold it.

If it is determined to hold the pressure, the estimated value Δp _wc (estimated pressure increase / decrease amount) of the w / c pressure increase / decrease amount is set to 0 in step 201 (FIG. 5). Then, the process proceeds to step 209 and step 2 which will be described later.
09 and 210 are executed, and this program in this loop is ended. In this case, the deviation Δp _e takes a value near zero, which means that the w / c pressure is controlled to be substantially near the target w / c pressure p ^* . Therefore, the command to the solenoid valve 2 is It is a holding command for the entire period of cycle T (see FIG.
As a result, the solenoid valve 2 maintains the holding position where the pressure is not increased or decreased.

On the other hand, if the result of the determination in step 111 is Yes, and it is determined that the pressure is to be increased, in this program example, the necessary increase is made in the loop from step 111 to step 202 (FIG. 5) and subsequent processing. While calculating the pressure command time, the w / c pressure after the pressure increase is estimated, and this program processing in the loop this time is ended. Further, in this program example, the relationship between the pressure increasing time and the pressure increasing amount to be used in the following w / c pressure increasing processing is also obtained in advance,
The data is stored in the memory as a pressure increase characteristic map described later, and necessary calculation is performed based on the relationship obtained in advance.

First, the process of step 202 is basically the ACC pressure which is the original pressure and w / c at the time of the control.
The content is to obtain the pressure difference from the pressure. In the control of the present embodiment, as described above, the pressure of the ACC 7 can be estimated and obtained. Therefore, in step 202, the estimated ACC pressure P obtained in step 107 is obtained.
_ACCn (current value) is used to estimate the P _ACCn value and estimated w / c pressure p
The differential pressure Δp _AW from _WCn (current value) is

[ _Expression 4] Δp _AW = P _ACCn −p _WCn ... Where the value Δp
_AW means that it represents the difference in pressure between w / c pressure and ACC pressure (pressure difference between the two) (see “(Step 20
(3) Description of function for obtaining pressure increase time Δt ”). Then, as described above, the ACC pressure is obtained as an accurate estimated value in this case (steps 101 to 107). Therefore, the differential pressure value obtained by applying the estimated value to the above equation is obtained. Δp _{AW is} also required to accurately reflect the pressure difference between the two.
Thus, then, in step 203, determine the pressure increasing time from the deviation Delta] p _e and the pressure difference Delta] p _AW obtained in step _{109 (Δt = f 2 (Δp} e, Δp AW)). That is, the estimated ACC pressure and the estimated w / c pressure (the estimated w / c before pressure increase)
A differential pressure Delta] p _AW and pressure), the deviation value Delta] p _e of the target w / c pressure and the estimated w / c pressure (increased pre- estimated w / c pressure), obtains the pressure increasing time Delta] t. This will be described below.

[Characteristics of Pressure Boosting Characteristic] In this case, the ACC pressure is used as a reference. FIG. 6 shows a pressure-increasing characteristic curve. In the figure, the w that is p1 lower than the ACC pressure is now obtained.
The time for increasing the pressure from the / c pressure to the w / c pressure that is p2 lower than the ACC pressure is t12. Also, p2 lower than ACC pressure w
The time for increasing the pressure from the / c pressure to the w / c pressure that is p3 lower than the ACC pressure is t23. Also, w that is p1 lower than the ACC pressure
The time required to increase the pressure from the / c pressure to the w / c pressure that is p3 lower than the ACC pressure is t13.

At this time, the relationship between t12, t23, and t13 is t13 = t12 + t23, and if the total pressure increasing time is the same, the same w / c is used when the ACC pressure is used as a reference.
It becomes pressure. On the other hand, considering w / c pressure = 0 as a reference, for example, as shown in FIG.
Since the same pressure increase amount is not obtained due to the difference in C pressure (the magnitude of ACC pressure), in this example, the ACC pressure is considered as a reference.

"Explanation of Function for Obtaining Pressure Boosting Time .DELTA.t (at Step 203)" From such characteristics of pressure boosting characteristics,
With reference to the ACC pressure, as shown in FIG. 8, the pressure increasing time required for increasing the pressure (Δp pressure increasing) from a w / c pressure lower than the ACC pressure by, for example, pA lower than the ACC pressure by a pressure lower by pB. Δt can be obtained. That is, A as shown in FIG.
It is obtained from a pressure increase characteristic map of w / c pressure based on CC pressure (this is stored in a memory in advance).

The method is as follows. [Procedure 1] Times tA and tB corresponding to −pA and −pB as shown in FIG. 8 are obtained from a map, respectively. [Procedure 2] Then, if these tA and tB are obtained, the pressure increasing time Δt value necessary for increasing Δp can be calculated from the pressure increasing time Δt = tB−tA.

In comparison with the program examples shown in FIGS. 3 to 5, pA = pressure difference Δp in this embodiment.
_AW (calculated value in step 202), pB = pressure difference Δp _AW −
Δp _e (Δp _e is the calculated value in step 109), and therefore, in step 203, the value Δp _AW is calculated according to the calculation method of [Procedure 1] and [Procedure 2] using the characteristic map as described above. It can be calculated pressure boosting period Δt value from the value Delta] p _e.

As described above, the pressure increase command time required to adjust the w / c pressure to the target w / c pressure is thus determined based on the difference between the estimated ACC pressure and the pre-increase estimated w / c pressure. , Can be calculated. Even if the relationship between the required pressure increase amount of the w / c pressure and the pressure increase time differs due to the differential pressure between the ACC pressure and the w / c pressure, which are the original pressure, the ACC pressure and w / c pressure are estimated in this way. However, by calculating the difference between the two and obtaining the pressure increasing time for the pressure increasing amount, the time for increasing the pressure by the required pressure increasing amount can be accurately calculated.

Returning to FIG. 5, once the value Δt is calculated, in this program example, in step 204, a pressure increase command is output during the pressure increase time Δt. FIG. 13 shows an example of how the pressure increase command is output. Boosting time Δ
When t is calculated, as shown in the figure, the output outputs a pressure increase command during Δt and issues a hold command during the remaining T-Δt.
The solenoid valve 2 is controlled to switch to the pressure increasing position and the holding position according to such a command. In this case,
The hydraulic pressure of the wheel cylinder 1 is controlled to increase toward the target by using the ACC pressure as a source pressure by controlling the solenoid valve 2 to increase or maintain pressure.

The step 205 following the step 204 is
Pressure increase time Δt and differential pressure Δp_AWTo increase amount Δp_WCSeeking
It is a step (Δp_WC= F₃(Δt, Δp_AW)). Boosting
Due to the command resolution and the response of the braking fluid pressure, Δt is not always
By increasing the pressure of _eIt is not always boosted, so again
Calculate the amount of pressure increase.

[Explanation of Function for Obtaining Pressure Increase (at Step 205)] In this case, the basic idea is as shown in FIG.
8 is applied, and similarly, as shown in FIG. 9, from w / c pressure pA lower than ACC pressure,
The amount of pressure increase when the time Δt is increased can be obtained.
Here, the pressure increase amount Δp is obtained by the following procedure as shown in FIG. 9 using the same pressure increase characteristic map as in FIG. 8 (FIG. 9).
Middle, see arrow).

[Procedure 11] -Time tA corresponding to pA
From the map. [Procedure 12] Adding pressure increasing time Δt to tA, tB = t
The time tB is calculated from A + Δt. [Procedure 13] The w / c pressure-pB corresponding to tB is obtained from the map. [Procedure 14] The pressure increase amount can be calculated from the pressure increase time Δt from Δp = (− pB) − (− pA). Also in this case, in comparison with the case of the program examples shown in FIGS. 3 to 5, in the present embodiment, pA = pressure difference Δp _AW , p
B = pressure difference Δp _AW -Δp _e, and the step 205
Then, the pressure increase amount Δp (Δp _WC ) is calculated from the pressure difference value Δp _AW which is the calculated value in step 202 and the pressure increase time Δt by the calculation method according to [Procedure 11] to [Procedure 14].
Then, the above calculation process is performed every time step 205 is executed,
Steps 209 and 210 are executed.

Step 209 is a process for calculating an estimated w / c pressure value to be applied in the next loop. Here, the estimated w / c pressure current value p _wcn is obtained by either step 201 in the case of the above-mentioned holding, step 205 in the case of the above-mentioned pressure increase, or step 208 in the case of the pressure reduction described later. Estimated value of w / c pressure increase / decrease amount Δ
add p _wc ,

The estimated w / c pressure p _{WCn + 1} after pressure increase / decrease is obtained by the _{following equation} : p _{WCn + 1} = p _wcn + Δp _wc . In the case of the above-mentioned holding, the value 0 is applied to the second term on the right side of the above equation, and as a result, p _{WC n + 1} = p _wcn , and step 210 is executed in that state.

In this case, the pressure is increased (Δp _wc > 0). Therefore, at this time, the value Δp _wc obtained in step 205 is used as the estimated pressure increase amount of the w / c pressure by the above equation 5. p
_{The value} added to _wcn is obtained as the estimated value of the w / c pressure after the pressure increase. Thus, the w / c pressure after the pressure increase for a predetermined time is appropriately estimated based on the difference between the estimated ACC pressure and the pre-pressure increase estimated w / c pressure. That is, the estimation of w / c pressure is AC
The estimated AC that is performed while estimating the C pressure and that is obtained
The differential pressure value Δp _AW is calculated from the C pressure current value p _ACCn and the estimated w / c pressure current value p _WCn , and the pressure increase amount Δp _wc value for a predetermined pressure increase time is calculated from the relationship obtained in advance (step 202).
205), the w / c pressure after pressure increase can be estimated (step 209). And this is the next step 2
By executing the update process of 10, in the next loop,
The estimated w / c pressure to be applied in this loop is read out and used as the current value.

In step 210, the estimated w / c pressure previous value p _{WCn-1 is set} to the estimated w / c pressure present value p _{WC n} , and the estimated w / C pressure present value p _wcn is _set to the estimated w / c pressure _next value p _{WCn. The} estimated ACC pressure previous value p _ACCn-1 is updated to ₊₁ (calculated value in step 209) to the estimated ACC pressure current value p _ACCn , and after this processing, the process returns to the start. That is, each time this step 210 is executed, in preparation for the processing in the next loop, the processing for rewriting the values of the estimated ACC pressure and the estimated w / c pressure is executed, and the processing of this program in this loop is ended.

In the case of increasing the pressure of the wheel cylinder 1, steps 101 → 102 → 104 → 105 or 10 are thus performed.
6 → 107 → 108 → 109 → 110 → 111 → 202
In a loop that goes through → 203 → 204 → 205 → 209 → 210, w / c pressure control is executed. W to be applied to calculation
/ C pressure value is sequentially rewritten, and the estimated w / c pressure after pressure increase is updated as a new value.
The CC pressure value can be calculated. Further, the next estimated ACC pressure is updated to the current value and the next estimated w / c pressure value is calculated. In this way, the estimated ACC pressure value and the estimated w / c pressure value are sequentially calculated.
The c pressure value is calculated.

In this case, even if the original ACC pressure is reduced by increasing the w / c pressure, as described above in this program example, the ACC pressure reducing amount relative to the w / c pressure increasing amount. The ACC pressure can be accurately estimated by previously obtaining the relationship, and the ACC pressure can be accurately estimated by previously obtaining the relationship between the ACC pressure increase amount and the pump drive time. ACC pressure estimation is realized. Then, the estimated ACC pressure is applied as basic data to both the w / c pressure estimation process after the pressure increase command and the calculation process of the pressure increase command time necessary for adjusting the w / c target pressure. And each can be accurate. The relationship between the pressure increase time and the pressure increase time of w / c pressure is as follows:
Since the pressure difference from the c pressure is different, the ACC pressure and the w / c pressure are estimated, the pressure difference is calculated, and the pressure increase amount with respect to the pressure increase time is obtained to accurately calculate the w / c pressure after the pressure increase. Can be estimated. Since the relationship between the required pressure increase amount of w / c pressure and the pressure increase time differs depending on the pressure difference between the ACC pressure that is the original pressure and the w / c pressure, the difference between the ACC pressure and the w / c pressure is estimated. By calculating the pressure and determining the pressure increasing time for the pressure increasing amount, the time for increasing the pressure by the required pressure increasing amount can be accurately calculated. Even if the pressure is increased by such a method, by estimating the w / c pressure and calculating the command time, the w / c pressure can be controlled according to the target value without using an expensive pressure sensor.

In controlling the w / c pressure, even if the amount of increase in the w / c pressure is the same, the ACC pressure of the accumulator 6 is large or small, and the ACC pressure and the wheel cylinder 1 before the pressure increase. It is possible to cope with the case where the pressure is different from the pressure, and the estimation can be made more accurate, the estimation accuracy can be easily increased, and accurate w / c pressure control can be achieved. In this program example, a method for obtaining a differential pressure between the ACC pressure and the w / c pressure is introduced in order to easily and accurately estimate, and for that reason, a pressure sensor for the ACC pressure is not provided, Moreover, without providing a pressure sensor for the w / c pressure, the ACC pressure of the original pressure is also estimated,
A method of achieving w / c pressure control while estimating both the pressure and the w / c pressure is realized. Further, in this case, if the calculation method using the pressure increase characteristic map based on the ACC pressure as described above is used, the control accuracy can be further increased and the accuracy can be improved.

Pressure reduction control of the wheel cylinder 1 is performed.
In this case, the read target w / c in step 108 of FIG.
Pressure p^*Based on the value, step 109 → step 110
Deviation Δp in the process of processing_eIs a predetermined value
It is time to take a negative value below. That is, step 1
If the determination result of 10 is Yes and it is determined that the pressure is reduced,
Step 206 (FIG. 5) is selected and the process proceeds to step 11.
From 0 to step 206 and below, first, step 2
At 06, deviation Δp_eValue and estimated w / c pressure current value p _wcnFrom
Decompression time Δt is calculated (Δt = f_Four(Δp_e, Δ
p_AW)). This will be described below.

[Characteristics of Pressure Reduction Characteristics] The pressure reduction characteristics are similar to the pressure increase characteristics. In FIG. 10, w / c pressure p1 to w /
The decompression time required to decompress to c pressure p2 is t12, w /
The pressure reduction time required to reduce the c pressure p2 to the w / c pressure p3 is t23. Also, from w / c pressure p1 to w / c pressure p
The pressure reduction time required to reduce the pressure to 3 is t13. At this time, t13 = t12 + t23, and if the total depressurization time is the same, the w / c pressure is the same.

[Explanation of Function for Decompression Time (at Step 206)] From the characteristics of the decompression characteristics as described above, it is necessary to reduce the w / c pressure by Δp from pA to pB as shown in FIG. It is possible to obtain a proper depressurization time Δt. That is, it is calculated using a pressure reduction characteristic map of w / c pressure as shown in FIG. The procedure in that case is as follows. [Procedure 21] Times tA and tB corresponding to pA and pB as shown in FIG. 11 are respectively obtained from the map. [Procedure 22] Then, based on these tA and tB, Δt
= TB-tA, the decompression time Δt value required to decompress Δp can be calculated. Here, in this case as well, in comparison with the case of the program examples of FIGS.
A = estimated w / c pressure current value p _WCn , pB = w / c pressure p _WCn
+ Δp _e (where Δp _e is a negative value). Therefore, in step 206, the value p
_The decompression time Δt value can be calculated from _WCn and the value Δp _e .

Next, referring to FIG. 5, the decompression time Δ
After the t value is calculated, in step 207, the decompression time
Decompression command is output during Δt. Figure 14 shows
An example of the output state when the pressure command is output is shown. Decompression time Δt
When calculated, the output is reduced during Δt as shown in the figure.
A command is output, and a hold command is issued for the remaining T-Δt. electromagnetic
The valve 2 controls switching between pressure reduction and holding according to such a command.
The brake fluid in the wheel cylinder 1 is stored in the reservoir tank.
The pressure is reduced to 3 and reduced pressure is applied. And the next step
In step 208, decompression time Δt and estimated w / c pressure current value
p _WCnDecompression amount estimated from Δp_WC(Δp_WC= F
_Five(Δt, p_WCn)). Here, the estimated pressure reduction amount Δp_wcIs negative
To be calculated.

Similarly to "Explanation of Function for Obtaining Decompression Amount (at Step 208)", using the decompression characteristic map, as shown in FIG. 12, the decompression amount when the time Δt is reduced from the w / c pressure pA. Δp can be obtained. That is, FIG.
Using the same depressurization characteristic map as above, it is obtained by the following procedure as shown in FIG. 12 (see the arrow in FIG. 12). [Procedure 31] The time tA corresponding to pA is obtained from the map. [Procedure 32] Adding decompression time Δt to tA, tB = t
The time tB is calculated from A + Δt. [Procedure 33] The w / c pressure pB corresponding to tB is obtained from the map. [Procedure 34] From Δp = pB-pA, the pressure reduction amount Δp (<
0) is calculated.

Also in this case, in comparison with the case of the program examples of FIGS. 3 to 5, in the present embodiment, pA = estimated w / c
Pressure present value p _WCn, pB = w / c pressure p _WCn + Δp _e next, in step 208, the value p _WCn and decompression time Δt
From this, the reduced pressure amount Δp (Δp _WC ) is calculated.

Thus, after step 208, the processes of step 209 and step 210 are executed,
This time the processing of this program in the loop ends. In this case, the second term on the right side of the equation 5 has a negative value Δp _WC
Is applied as an estimated decompression amount of w / c pressure, and this is calculated as w / c
A value subtracted from the current pressure value p _wcn is obtained as an estimated value of the w / c pressure after decompression, and based on this, the estimated w / c pressure rewriting and updating process for the next loop is performed in the same manner as described above. Is executed, and the rewriting and updating process for the estimated ACC pressure value is also executed. In the next loop, the above-described processes after step 101 are executed.

Thus, in the case of decompression, step 101 →
103 → 104 → 105 or 106 → 107 → 108
→ 109 → 110 → 206 → 207 → 208 → 209 →
In the loop passing through 210, w / c pressure control is executed.
The w / c pressure value estimated for each cycle in this process is
In the case of holding / holding the w / c pressure or switching the control to increase the pressure, the hydraulic pressure of the wheel cylinder 1 at that time is taken over, and the ACC pressure is similarly accurately estimated. Will be handed over.

That is, when the brake fluid in the wheel cylinder 1 is drained, there is no fluctuation in the direction in which the pressure in the accumulator 6 decreases due to the pressure reduction control, but the ACC pressure is kept within the predetermined range based on the pressure switch 7 described above. Depending on the ON operation of the pump 4 that regulates the pressure to
There is a change in the increasing direction of the ACC pressure which becomes the original pressure when the pressure increasing control is performed. In this program example, the processes of steps 101 to 107 are executed even during the depressurization control. Therefore, when applicable, the value corresponds to the pump drive time and the value Δp _{ACC is} successively added to the estimated accumulator pressure value at that time. ⁺ Minutes are added. Therefore, accurate estimation of the ACC pressure can be continuously performed in consideration of driving / stopping of the accumulator pump 6, and if the w / c pressure control is changed to the pressure increase control, Assuming that the current value of the estimated ACC pressure indicates the pressure in the accumulator 6 at that time, it is appropriately inherited as the estimated ACC pressure value that should be applied to the above-described pressure increase control calculation (steps 202 to 205). Therefore, the necessary increase / decrease control of the w / c pressure is performed while maintaining high estimation accuracy and control accuracy.

As described above, the ACC pressure is estimated and w / c
By estimating and controlling the pressure, the w / c pressure can be accurately controlled without using an expensive pressure sensor. By controlling the w / c pressure according to the target value, for example, in the traction control device, when the drive wheels slip,
Insufficient or excessive w / c pressure does not occur, slip can be reliably suppressed, and acceleration performance does not decrease. Also,
For example, even when controlling the left / right w / c pressure independently to control the behavior of the vehicle while turning or going straight, an unintended moment is not generated, and the behavior of the vehicle as intended can be controlled. Further, for example, in the following traveling control device as described above, the actual vehicle speed can be controlled according to the target vehicle speed.

The present invention is not limited to the above TCS and the like, but may be applied to a device (for example, other active brake, automatic brake, etc.) that increases the pressure of the wheel cylinder by an external hydraulic pressure source (other than the master cylinder pressure). Needless to say, it is applicable.

[0078]

According to the present invention, in the braking hydraulic pressure control capable of increasing the wheel cylinder pressure of the wheel to be controlled of the vehicle by the external hydraulic pressure source, even when the wheel cylinder pressure is controlled to be increased, The pressure of the external hydraulic pressure source, which is the source pressure of the wheel cylinder pressure, can also be estimated, the wheel cylinder pressure can be estimated, the command time can be calculated, and the pressure of the external hydraulic pressure source during pressure increase control can also be changed. It can be reflected appropriately in the control, and it is possible to perform estimation and control that also consider the pressure difference between the source pressure and the wheel cylinder pressure, and the estimation accuracy will be lower than that without the source pressure. In addition, this can be easily realized without adding an expensive pressure sensor, the wheel cylinder pressure of the wheel to be controlled can be controlled more precisely according to the target value, and the control accuracy can be improved.

By estimating the original pressure and estimating and controlling the wheel cylinder pressure, the wheel cylinder can be accurately controlled and the control accuracy can be improved. Therefore, in the traction control device, when the drive wheels slip, The wheel cylinder pressure does not become insufficient or excessive, slip can be reliably suppressed, and acceleration performance does not deteriorate. Further, the follow-up running control device can control the actual vehicle speed according to the target vehicle speed. Further, the invention is applied to the case where the left and right wheel cylinder pressures are independently controlled to control the behavior of the vehicle while turning or going straight, and an unintended moment is not generated, and the desired behavior of the vehicle can be controlled.

Further, the external hydraulic pressure source includes an accumulator for obtaining the original pressure of the wheel cylinder pressure, has a pump mechanism for adjusting the accumulator pressure to a required pressure, and stops the driving of the pump. The source pressure estimating means includes a detecting means for detecting, based on a change in the estimated wheel cylinder pressure or a previous value and a current value of the estimated wheel cylinder pressure, and the drive stop information of the pump detected by the detecting means. As a means for estimating pressure, the invention can be implemented and the above can be realized as well. In this case, the accumulator pressure, which is the original pressure, is estimated by considering that the accumulator pressure in the accumulator decreases as the wheel cylinder pressure increases, while the accumulator pressure increases as the pump is driven. Accurate estimation of the accumulator pressure can be made possible.

Further, the source pressure estimating means estimates the accumulator pressure, and the wheel cylinder estimating means determines the wheel after the pressure increase command for a predetermined time based on the pressure difference between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase. The means for estimating the cylinder pressure and calculating the pressure increase command time is necessary for adjusting the wheel cylinder pressure to the target wheel cylinder pressure based on the differential pressure between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase. The present invention can be implemented by calculating the pressure increasing time, and the above can be similarly realized. In this case, the wheel cylinder estimation and the pressure increase command time calculation can be performed based on the estimated accumulator pressure obtained by the above estimation. Therefore, the estimation of the wheel cylinder pressure after the pressure increase command for the predetermined time according to the pressure difference between the estimated accumulator pressure and the estimated wheel cylinder pressure before the pressure increase can be made more accurate, and the necessary wheel cylinder pressure can be obtained. Even if the relationship between the pressure increase time and the pressure increase time differs depending on the differential pressure between the accumulator pressure and the wheel cylinder pressure, which is the original pressure, it can be handled appropriately, and the differential pressure can be calculated by estimating the accumulator pressure and the wheel cylinder. ,
By calculating the pressure boosting time for the pressure boosting amount, it is possible to accurately calculate the time for boosting by the required pressure boosting amount, and in that case also, using the estimated accumulator pressure value obtained as the above accurate value, The pressure increase command time can be calculated more accurately.

Further, the relationship between the previously obtained increase amount of the wheel cylinder pressure and the reduced amount of the accumulator pressure, the previously obtained relationship between the pump driving time and the increased amount of the accumulator pressure, and the previously obtained accumulator pressure. And the wheel cylinder pressure difference, the storage means stores the relationship between the pressure increase time and the wheel cylinder pressure increase amount, and the estimated wheel cylinder pressure previous value is stored in the storage means. Estimated wheel cylinder pressure This time, the amount of pressure reduction of accumulator pressure is calculated, the amount of increase in accumulator pressure with respect to the pump drive time is calculated, and the current value of accumulator pressure is estimated, and this estimated accumulator pressure current value and estimated wheel cylinder pressure this time The differential pressure is calculated from the value and the wheel for a predetermined pressure increasing time is calculated from the relationship stored in the storage means. Calculated cylinder-pressure pressure amount, to estimate the wheel cylinder pressure of the booster after pressurization, a structure to perform accumulator pressure estimation and the wheel cylinder pressure estimation, the present invention can be carried out similarly can be achieved above. In this case, preferably, depending on the system to be applied, the related data is obtained in advance according to the accumulator, pump, etc. used and stored in the memory of the controller, and based on this, each estimation is easily and accurately performed. be able to. Therefore, in estimating the accumulator pressure, the accumulator can be accurately estimated by obtaining the relationship between the pressure increase amount of the wheel cylinder pressure and the pressure reduction amount of the accumulator pressure in advance, and the increase amount of the accumulator pressure with respect to the pump drive time. The accumulator pressure can be accurately estimated by previously obtaining the relationship. The relationship between the pressure increase time and the wheel cylinder pressure increase time depends on the pressure difference between the accumulator pressure, which is the original pressure, and the wheel cylinder pressure.Therefore, the accumulator pressure and the wheel cylinder pressure are estimated and the pressure difference is calculated. By obtaining the pressure increase amount with respect to the pressure increase time, the wheel cylinder after the pressure increase can be accurately estimated.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a braking hydraulic pressure control device of the present invention, and is a diagram showing a configuration relating to one wheel to be controlled.

FIG. 2 is a functional block diagram showing control contents in the same example.

FIG. 3 is a flowchart showing a part of an example of a control program executed by a controller.

FIG. 4 is a flowchart showing another part of the same.

FIG. 5 is a flowchart showing another part of the same.

FIG. 6 is a diagram illustrating an example of a pressure-increasing characteristic curve for explaining the control content and for explaining the relationship between the pressure-increasing time and the w / c pressure based on the ACC pressure.

FIG. 7 is a characteristic diagram shown as a comparative example.

FIG. 8 is a diagram showing an example of a method of calculating a pressure increase time in pressure increase control using a pressure increase characteristic map.

FIG. 9 is an explanatory diagram similarly showing an example of a procedure for calculating a pressure increase amount.

FIG. 10 is a diagram showing an example of a pressure reduction characteristic curve for explaining the relationship between the pressure reduction time and the w / c pressure.

FIG. 11 is a diagram showing an example of a decompression time calculation method for decompression control using a decompression characteristic map.

FIG. 12 is an explanatory diagram similarly showing an example of a procedure for calculating the pressure reduction amount.

FIG. 13 is a diagram of an output waveform at the time of outputting the pressure increase command, which is used to explain the output of the pressure increase command.

FIG. 14 is a diagram of an output waveform at the time of outputting the pressure reducing command, which is used to explain the output of the pressure reducing command.

[Explanation of symbols]

 1 w / c 2 solenoid valve 3 reservoir tank 4 pump 5 pump drive motor 6 accumulator 7 pressure switch 8 controller 10 wheels

Claims (5)

[Claims] 1. A braking fluid pressure control device capable of increasing the pressure of a wheel cylinder of a vehicle control target wheel by an external fluid pressure source, wherein the wheel cylinder uses a supply pressure from the external fluid pressure source as a source pressure. Target hydraulic pressure calculating means for calculating the target wheel cylinder pressure, estimating means for estimating the supply pressure from the external hydraulic pressure source, and the target wheel cylinder pressure for increasing or decreasing the wheel cylinder pressure for a predetermined time. A wheel cylinder pressure including a solenoid valve controlled so as to regulate the pressure, and a means for estimating the wheel cylinder pressure after a predetermined time increase based on the estimated value of the original pressure by the estimation means and the estimated wheel cylinder pressure value. Estimating means for adjusting the wheel cylinder pressure to the target wheel cylinder pressure based on the estimated value of the original pressure, the estimated wheel cylinder pressure value and the target wheel cylinder pressure value Comprising means for calculating the increasing pressure command time for essential that the solenoid valve, the brake fluid pressure control device, characterized in that it comprises a control command operation unit. 2. The external hydraulic pressure source includes an accumulator for obtaining a source pressure of a wheel cylinder pressure, a pump mechanism for adjusting the accumulator pressure to a required pressure, and a drive stoppage of the pump. The detection means for detecting, the source pressure estimation means, based on the change of the estimated wheel cylinder pressure or the previous value and the current value of the estimated wheel cylinder pressure, and the drive stop information of the pump detected by the detection means, The braking hydraulic pressure control device according to claim 1, which is means for estimating the accumulator pressure. 3. The source pressure estimating means estimates an accumulator pressure, and the wheel cylinder estimating means calculates a pressure increase command for a predetermined time based on a differential pressure between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase. The means for estimating the wheel cylinder pressure and calculating the pressure increase command time is for adjusting the wheel cylinder pressure to the target wheel cylinder pressure based on the pressure difference between the estimated accumulator pressure and the estimated wheel cylinder pressure before pressure increase. The braking hydraulic pressure control device according to claim 2, wherein a pressure increase time required for the above is calculated. 4. A relationship between a preliminarily obtained increase amount of the wheel cylinder pressure and a decompression amount of the accumulator pressure, a preliminarily obtained relation between the pump driving time and the accumulator pressure increasing amount, and a preliminarily obtained accumulator pressure. There is a storage means for storing the relationship between the pressure increase time of the wheel cylinder pressure and the amount of increase in the wheel cylinder pressure, which is estimated as the previous value of the estimated wheel cylinder pressure from the relationship stored in the storage means. Calculate the decompression amount of the accumulator pressure from the current wheel cylinder pressure value, calculate the pressure increase amount of the accumulator pressure with respect to the pump drive time, and estimate the current value of the accumulator pressure. Then, the differential pressure is calculated, and the wheel cylinder for a predetermined pressure increasing time is calculated from the relationship stored in the storage means. The braking hydraulic pressure control device according to claim 2 or 3, wherein an accumulator pressure estimation and a wheel cylinder pressure estimation are performed so as to obtain a pressure increase amount and estimate a wheel cylinder pressure after the pressure increase. . 5. The target wheel cylinder pressure is a target wheel cylinder pressure of a driving wheel during drive slip control in traction control, or a target wheel cylinder pressure for controlling braking force during deceleration control in follow-up running control. Either the target wheel cylinder pressure, or the target wheel cylinder pressure of the control target wheel when controlling the wheel cylinder pressures of the left and right wheels independently in vehicle behavior control, or two or more of them The braking fluid pressure control device according to claim 1, claim 2, claim 3, or claim 4, wherein