JP2007030749A - Differential diameter rate calculating method for wheel, and differential diameter rate calculating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a wrong calculation of the differential diameter rate of a wheel accompanying the turning of a vehicle as much as possible. <P>SOLUTION: The differential diameter rates for the right and left wheels are calculated based on right and left wheel speeds being continuously detected by wheel speed sensors which detect the wheel speeds of the right and left wheels which are coaxially arranged. This calculating method has a process in which the wheel speeds of the right and left wheels are acquired, and a process in which the differential diameter rate is calculated from a rate of the wheel speeds of the right and left wheels. When the difference between the wheel speeds of the right and left wheels, or a variation rate of the difference becomes larger than a specified value, a variation amount of the differential diameter rate which is calculated this time to the value of the differential diameter rate which is calculated last time is limited. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a different diameter ratio calculation method and a different diameter ratio calculation device between left and right wheels, and more specifically, a different diameter ratio calculation method and a different diameter ratio calculation device for a wheel that can correctly calculate the different diameter ratio during turning. About.

When vehicle behavior control such as anti-lock brake control is performed, acceleration in the lateral direction of the vehicle body (referred to as “lateral acceleration” in this specification) is detected or estimated and used for control information. is there. The lateral acceleration in this case can also be detected directly by using an acceleration sensor, but it is disadvantageous in terms of cost to provide an acceleration sensor, so the lateral acceleration is calculated by using the difference between the left and right wheel speeds. Calculation is performed (for example, refer to Patent Document 1).
However, the wheel speed is generally calculated from the number of rotations of the wheel and the set wheel diameter based on the signal of the rotation pulse generator provided on the wheel, that is, the set circumference of the wheel. Therefore, the wheel speed depends on the circumference of the wheel, that is, the wheel diameter. Therefore, even when the lateral acceleration is calculated by appropriately calculating the different diameter ratio, which is the ratio of the left and right wheel diameters, so that the wheel speed can be correctly estimated even when the right and left wheels are different in size, Correction based on rate.

JP-A-8-26089

However, it is common to estimate the different diameter ratio itself from the left and right wheel speeds. While the vehicle is turning, the left and right wheel speeds change due to the difference in turning radius between the outer and inner wheels, Then, there is a problem that the value of the different diameter ratio is different from the actual value.
This invention is made | formed in view of such a background, Comprising: This invention makes it a subject to suppress the miscalculation of the different diameter ratio of the wheel accompanying turning of a vehicle as much as possible.

  In order to solve the above-described problems, the present invention is based on the left and right wheel speeds continuously detected by the wheel speed sensor that detects the wheel speeds of the left and right wheels arranged coaxially. A method for calculating a different diameter ratio, comprising the steps of obtaining wheel speeds of the left and right wheels, and calculating a different diameter ratio based on a ratio of wheel speeds of the left and right wheels, When the difference between the wheel speeds of the left and right wheels or the rate of change of the difference exceeds a predetermined value, the change of the different diameter ratio calculated this time relative to the previously calculated different diameter ratio value is limited. To do.

In this way, when the difference between the wheel speeds of the left and right wheels is greater than the predetermined value, the current calculation with respect to the previously calculated value of the different diameter ratio so that the calculation result of the different diameter ratio is less affected. By limiting the change in the different diameter ratio, the wrong diameter ratio is not erroneously calculated by turning motion, and the vehicle is operated by correctly calculating the lateral acceleration using the calculated different diameter ratio. It can be controlled appropriately.
The determination of whether or not the difference between the wheel speeds of the left and right wheels is greater than a predetermined value may be made by determining the ratio of the wheel speeds of the left and right wheels in terms of numerical values. Similarly, when determining whether or not the rate of change of the difference is greater than a predetermined value, it is not limited to determining the ratio between the previous value and the current value of the difference between the left and right wheels. You may judge by taking the difference.

  Further, the device of the present invention that solves the above-described problem is based on the left and right wheel speeds continuously detected by the wheel speed sensor that detects the wheel speeds of the left and right wheels arranged coaxially. An apparatus for calculating a different diameter ratio of a wheel, comprising: a different diameter ratio calculating section that calculates a different diameter ratio based on a ratio of wheel speeds of the left and right wheels, wherein the different diameter ratio calculating section When the wheel speed difference or the change rate of the difference becomes larger than a predetermined value, the change of the different diameter ratio calculated this time with respect to the value of the different diameter ratio calculated last time is limited.

  In such an apparatus, it is desirable that the different diameter ratio calculation section tightens the restriction on the change in the different diameter ratio when the wheel speed ratio stabilization time is shorter than when the wheel speed ratio is stable.

  The stabilization time here refers to the time during which the change in the wheel speed ratio between the left and right wheels is within a predetermined range. The method of determining the predetermined range is arbitrary and may be variable. Further, whether or not the ratio of the wheel speeds is within a predetermined range may be determined based on whether or not the difference between the wheel speeds of the left and right wheels is within the predetermined range in terms of handling of numerical values.

  According to the present invention, it is possible to reduce the influence of the difference in wheel speed between the left and right wheels during the turning of the vehicle on the calculation result of the different diameter ratio, and to accurately calculate the different diameter ratio. Further, by controlling the hydraulic pressure of the vehicle brake using the calculated different diameter ratio, the vehicle can be appropriately controlled.

[First Embodiment]
Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the drawings to be referred to, FIG. 1 is a configuration diagram of a vehicle including a vehicle brake hydraulic pressure control device according to the first embodiment, and FIG. 2 is a diagram of the vehicle brake hydraulic pressure control device according to the first embodiment. It is a brake fluid pressure circuit diagram.
As shown in FIG. 1, a vehicular brake hydraulic pressure control device 100 to which a different diameter ratio calculation method of the present invention is applied is used to appropriately control a braking force (brake hydraulic pressure) applied to each wheel T of a vehicle CR. It mainly includes a hydraulic unit 10 provided with an oil passage and various parts, and a control device 20 for appropriately controlling various parts in the hydraulic unit 10. Further, a wheel speed sensor 91 for detecting the wheel speed of each wheel T of the vehicle CR, specifically, the rotational speed of the wheel T is connected to the control device 20 of the vehicle brake hydraulic pressure control device 100. .
The control device 20 includes, for example, a CPU, a RAM, a ROM, and an input / output circuit, and performs various arithmetic processes based on an input from the wheel speed sensor 91 and a program and data stored in the ROM, thereby controlling the control device 20. Execute. The wheel cylinder H is a fluid that converts the brake fluid pressure generated by the master cylinder M and the vehicle brake fluid pressure control device 100 into the operating force of the wheel brakes FL, RL, FR, RR provided on each wheel T. Each of which is connected to the hydraulic unit 10 of the vehicle brake hydraulic pressure control device 100 via a pipe.

  As shown in FIG. 2, the vehicular brake fluid pressure control device 100 includes a master cylinder M that generates brake fluid pressure corresponding to the pedaling force applied by the driver to the brake pedal P, wheel brakes FL, RR, RL, and FR. It is arranged between. The two output ports M1 and M2 of the master cylinder M are connected to the inlet port 121 of the pump body 10a which is the base body, and the outlet port 122 of the pump body 10a is connected to each wheel brake FL, RR, RL and FR. Yes. In normal times, an oil passage is formed from the inlet port 121 to the outlet port 122 in the vehicle brake fluid pressure control device 100 so that the pedal force of the brake pedal P is applied to each wheel brake FL, RR, RL, It is transmitted to the FR.

  The vehicle brake hydraulic pressure control device 100 is provided with four inlet valves 1, four outlet valves 2, and four check valves 1a corresponding to the respective wheel brakes FL, RR, RL, FR. In addition, two reservoirs 3, two pumps 4, two dampers 5, and two orifices 5a are provided corresponding to the output hydraulic pressure paths 81 and 82 corresponding to the output ports M1 and M2, respectively. An electric motor 6 for driving is provided.

  The inlet valve 1 is a normally open solenoid valve disposed between each wheel brake FL, RR, RL, FR and the master cylinder M. The inlet valve 1 is normally open to allow the brake hydraulic pressure to be transmitted from the master cylinder M to the wheel brakes FL, RR, RL, FR. In addition, the inlet valve 1 is blocked by the control device 20 when the wheel is about to be locked, thereby cutting off the hydraulic pressure transmitted from the brake pedal P to each wheel brake FL, RR, RL, FR.

  The outlet valve 2 is a normally closed electromagnetic valve disposed between each wheel brake FL, RR, RL, FR and each reservoir 3. Although the outlet valve 2 is normally closed, the brake fluid pressure applied to each wheel brake FL, RR, RL, FR is applied to each reservoir by being released by the control device 20 when the wheel is about to lock. Escape to 3.

  The check valve 1a is connected to each inlet valve 1 in parallel. This check valve 1a is a valve that allows only the flow of brake fluid from each wheel brake FL, RR, RL, FR side to the master cylinder M side, and an inlet valve when the input from the brake pedal P is released. Even when 1 is closed, inflow of brake fluid from each wheel brake FL, RR, RL, FR side to the master cylinder M side is allowed.

The reservoir 3 has a function of absorbing brake fluid that is released when each outlet valve 2 is opened.
The pump 4 has a function of sucking the brake fluid absorbed in the reservoir 3 and returning the brake fluid to the master cylinder M via the damper 5 and the orifice 5a. As a result, the pressure state of each of the output hydraulic pressure paths 81 and 82 reduced by the absorption of the brake hydraulic pressure by the reservoir 3 is recovered.

  The inlet valve 1 and the outlet valve 2 control the hydraulic pressure in the wheel cylinders H of the wheel brakes FL, RR, RL, FR by the control device 20 controlling the open / closed state. For example, in a normal state in which the inlet valve 1 is open and the outlet valve 2 is closed, if the brake pedal P is depressed, the hydraulic pressure from the master cylinder M is transmitted to the wheel cylinder H as it is, and the pressure increases. When the valve 1 is closed and the outlet valve 2 is opened, the brake fluid flows out from the wheel cylinder H to the reservoir 3 side to be in a reduced pressure state. When both the inlet valve 1 and the outlet valve 2 are closed, the wheel cylinder H Fluid pressure is maintained. The control device 20 outputs a control signal to each of the inlet valves 1 and each of the outlet valves 2 in order to switch these three states in accordance with the target brake hydraulic pressure in each wheel cylinder H.

FIG. 3 is a block configuration diagram of the brake hydraulic pressure control device according to the first embodiment, and FIG. 4 is a block configuration diagram illustrating details of the different diameter ratio calculation unit.
As shown in FIG. 3, the control device 20 controls each inlet valve 1 and outlet valve 2 (see FIG. 2) in the hydraulic unit 10 based on the rotational speed of the wheel T detected by the wheel speed sensor 91 of each wheel. The operation of each wheel brake FL, RR, RL, FR is controlled by controlling the opening / closing operation.
The control device 20 includes a different diameter ratio calculation unit 21, a target hydraulic pressure setting unit 22, a valve drive unit 23, and a storage unit 29 as functional units. The following functional units appropriately store data in the storage unit 29 when performing processing such as calculation and determination.

The different diameter ratio calculation unit 21 corresponds to a different diameter ratio calculation apparatus that implements the different diameter ratio calculation method of the present invention. The different diameter ratio calculation unit 21 of the present embodiment estimates the different diameter ratio based on the wheel speed of the left rear wheel and the wheel speed of the right rear wheel. The wheel speed used to calculate the different diameter ratio is preferably a driven wheel having good followability to the road surface, but it is not always necessary, and the wheel speeds of driving wheels or four wheels may be used.
As shown in FIG. 4, the different diameter ratio calculation unit 21 includes a wheel speed calculation unit 21a, a left / right speed ratio calculation unit 21b, a stabilization time calculation unit 21c, a change amount limit value setting unit 21d, A different diameter ratio calculation unit 21e is provided.

The wheel speed calculation unit 21a calculates the wheel speeds V _L and V _R by multiplying the wheel radii based on the wheel rotation speeds ω _L and ω _R output from the wheel speed sensors 91 of the left rear wheel and the right rear wheel, respectively. To do. The calculated wheel speeds V _L and V _R are output to the left / right speed ratio calculation unit 21b.

The left / right speed ratio calculation unit 21b calculates a left / right speed ratio RV _RL that is a ratio of the left and right wheel speeds V _L and V _{R by} the following equation (1).
RV _RL = V _R / V _L (1)
The calculated left / right speed ratio RV _RL is output to the stabilization time calculator 21c and the left / right different diameter ratio calculator 21e.
The left / right speed ratio RV _RL means the ratio of the diameters of the left and right wheels if the vehicle CR is traveling straight. This is because, when the diameters of the left and right wheels are different, the rotational speeds of the wheels differ, so that the wheel speed ratio is the diameter ratio. On the other hand, when the vehicle CR is turning, the left / right speed ratio RV _RL means the ratio of the left and right wheel diameters, and its value is greatly influenced by the difference in the turning radius of the wheels. Therefore, in the present invention, when the value of the left / right speed ratio RV _RL is large, the change in the different diameter ratio R (n) is limited when calculating the different diameter ratio R (n). In the present specification, (n) in each variable indicates the current calculated value, and (n−1) indicates the previous calculated value. In addition, when the previous calculation value is not used for the calculation and only the current calculation value is used, (n) is not particularly shown.

Stabilization time calculation unit 21c is a functional unit for calculating the degree of variation in the lateral velocity ratio RV _RL. Specifically, the value of the left / right speed ratio RV _RL is within a predetermined range centering on the stored stability reference value RV _HOLD , for example, as shown in FIG. 6 (a), stable from the stabilization time reference value RV _HOLD. A time varying within the range of the range threshold TH _V1 is counted as the stable time ST. If the value of the left / right speed ratio RV _RL fluctuates beyond the predetermined range from the stabilization time reference value RV _HOLD , the stabilization time ST is reset to 0 and counted again. In that case, the stabilization time reference value RV _HOLD is replaced with the left-right speed ratio RV _RL at that time. The stabilization time reference value RV _HOLD is output to the change amount limit value setting unit 21d.

The change amount limit value setting unit 21d sets a change amount limit value α that is an upper limit value of the change amount of the different diameter ratio in order to prevent excessive fluctuation of the calculated different diameter ratio R (n). This setting is set with reference to the map stored in the storage unit 29 based on the right / left speed ratio RV _RL and the stabilization time ST. The change amount limit value α is preferably set such that the limit value increases as the stabilization time ST increases, and decreases as the stabilization time ST decreases. For example, when the stabilization time ST is greater than the stabilization time threshold value TH _ST (for example, the size shown in FIG. 6B), the change amount limit value α may be that the vehicle CR is traveling straight. Since it is high, a constant value α1 is taken, and when the stabilization time ST is smaller than the stabilization time threshold TH _ST , it is likely that the vehicle CR is turning, so 0 is taken.
Of course, the value may be set more finely according to the stabilization time ST. Further, the change amount limit value α may be set in more detail based not only on the stabilization time ST but also on the rear wheel left-right speed difference dVR _RL and the front wheel left-right speed difference dVF _RL . For example, the reference value of the variation limit value α corresponding to the stabilization time ST is α1, and the correction coefficients kα ₁ and kα ₂ are prepared as maps corresponding to dVR _RL and dVF _RL. It is good to ask. In Equation (2), A [B] indicates that A is determined by a map or a function based on the value of B. For example, α1 [ST] is that the value of α1 is determined by a function based on ST. Indicates.
α = α1 [ST] × kα ₁ [dVR _RL ] × kα ₂ [dVF _RL ] (2)
The set change amount limit value α is output to the left / right different diameter ratio calculation unit 21e.

The right / left different diameter ratio calculation unit 21e calculates the current different diameter ratio R (n) from the left / right speed ratio RV _RL , the change amount limit value α, and the previous different diameter ratio R (n−1) stored in the storage unit 29. ). Specifically, the smaller one of | RV _RL −R (n−1) | and α is determined as the amount of change of the different diameter ratio R (n) with respect to the different diameter ratio R (n−1), and R ( n−1) is increased or decreased by | RV _RL −R (n−1) | or α.
In other words, the previous different diameter ratio R (n-1), if the difference between the left and right velocity ratio RV _RL is large, only the value of the change amount limiting value α to the previous different diameter ratio R (n-1) increased or decreased In this way, the change in the different diameter ratio R (n) during turning is reduced.
The calculated different diameter ratio R (n) is output to the target hydraulic pressure setting unit 22.
As the difference between the left / right speed ratio RV _RL and the previously calculated different diameter ratio R (n−1) increases, the different diameter ratio changes so that the different diameter ratio R (n) quickly follows the left / right speed ratio RV _RL. The amount may be determined. For example, the different diameter ratio R (n) may be calculated by the following formula (3) using the variation limit value α as a coefficient.
R (n) = R (n−1) + α × (RV _RL −R (n−1)) (3)

  The target hydraulic pressure setting unit 22 is configured to change the wheel brakes FL, RL, FR, RR based on the different diameter ratio R (n) calculated by the different diameter ratio calculation section 21 and the rotational speed ω of the wheel T detected by the wheel speed sensor 91. Set the target hydraulic pressure. This setting method may be performed by a conventionally known method and is not particularly limited. As an example, the wheel speed V of each wheel T is calculated from the rotational speed ω of the four wheels, and the vehicle body speed is estimated from the wheel speed V. Then, the slip ratio is calculated from the vehicle body speed and the wheel speed V. Further, based on the lateral acceleration Gy and the longitudinal vehicle body acceleration, a combined acceleration is calculated, and a road friction coefficient is estimated from the combined acceleration. When calculating the lateral acceleration Gy, the calculation is performed using the different diameter ratio R (n). Based on the friction coefficient, the slip ratio, and the current hydraulic pressure of the wheel cylinder H, the target hydraulic pressures of the wheel brakes FL, RL, FR, and RR can be set.

  The valve drive unit 23 is configured by a hydraulic unit by a conventionally known method so that the hydraulic pressure of the wheel cylinder H of each wheel brake FL, RL, FR, RR matches the target hydraulic pressure set by the target hydraulic pressure setting unit 22. A pulse signal for operating each inlet valve 1 and outlet valve 2 in 10 is output to the hydraulic unit 10. For example, as the deviation between the current hydraulic pressure of the wheel cylinder H and the target hydraulic pressure increases, this pulse signal outputs more pulses to increase or decrease the brake hydraulic pressure. Further, when the deviation between the current hydraulic pressure of the wheel cylinder H and the target hydraulic pressure is small, the hydraulic pressure of the wheel cylinder H is set to the holding state. Note that the current hydraulic pressure of the wheel cylinder H may be measured by a sensor or may be estimated by calculation.

The operation of the vehicular brake hydraulic pressure control apparatus 100 will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart for explaining processing for calculating the different diameter ratio of the vehicle brake hydraulic pressure control device according to the first embodiment, and FIG. 6 shows the vehicle brake hydraulic pressure control device according to the first embodiment. 5 is a timing chart showing temporal changes in a left / right speed ratio RV _RL (a), a stabilization time ST (b), and a change amount limit value (c) during turning of a mounted vehicle. Note that in the chart of FIG. 6 (a), superimposed on a change of the left and right velocity ratio RV _RL shows the variation of the different diameter ratio R (n).

As shown in FIG. 5, first, the wheel speed calculation unit 21a calculates the wheel speeds V _L and V _R from the rotational speeds ω _L and ω _{R of} the left and right rear wheels detected by the wheel speed sensor 91 (S101). . Then, the left / right speed ratio calculation unit 21b calculates the left / right speed ratio RV _RL based on the equation (1) (S102). As shown in FIG. 6A, the left / right speed ratio changes away from 1 in accordance with the turning operation of the vehicle CR. And when it becomes larger than 1, the right wheel is turning faster than the left wheel, so it turns left. When it becomes smaller than 1, it turns right. Will be.

Next, it is determined whether the absolute value of the difference between the left / right speed ratio RV _RL and the stable time reference value RV _HOLD is smaller than the stable range threshold TH _V1 (S103). If the difference in RV _HOLD is smaller than the stable range threshold TH _V1 (S103, Yes), this means that the left / right speed ratio RV _RL has not changed much, and the stable time is incremented and updated (S106). . RV difference _HOLD is, if greater than the stable range threshold TH _V1 (S103, No), the left and right velocity ratio RV _RL is that it varies greatly from the stable time reference value RV _HOLD, stable time reference value RV _{HOLD Is} replaced with the current left-right speed ratio RVRL and updated (S104). Then, the stabilization time ST is cleared to 0 (S105). The above steps S103 to S106 are the calculation process of the stable time ST.
As shown in FIG. 6B, the stabilization time ST calculated in this way is cleared before it becomes a large value while the left-right speed ratio RV _RL changes suddenly, and the left-right speed ratio RV _RL While is not changing much, it is incremented to a large value.

Then, the change amount limit value setting unit 21d sets the change amount limit value α based on the equation (2) (S107). The change amount limit value α changes according to the value of the stabilization time ST. If a simple example is shown, the stabilization time ST exceeds the stabilization time threshold TH _ST as shown in FIG. Only when is a constant value α1.

Next, the different diameter ratio R (n) is calculated based on RV _RL , R (n−1) and α by the left / right different diameter ratio calculation unit 21e. Specifically, it is determined whether or not the absolute value of RV _RL −R (n−1) is larger than α. If the absolute value is larger (S108, Yes), the different diameter ratio R (n) according to the following equation (4). Is calculated.
R (n) = R (n-1) + _RVRL- R (n-1) (4)
On the other hand, when the absolute value of RV _RL −R (n−1) is not larger than α (S108, No), it is determined whether or not RV _RL is larger than R (n−1). S110, Yes), R (n) is calculated by adding α to R (n-1) (S111), and if small (S110, No), subtracting α from R (n-1) R (n) is calculated (S112).

Thus, when the difference between the previous different diameter ratio R (n−1) and the left / right speed ratio RV _RL is large, the left / right different diameter ratio calculation unit 21e sets the previous different diameter ratio R (n−1) to the previous different diameter ratio R (n−1). Increase or decrease by the change amount limit value α. Therefore, as shown in FIG. 6A, since the stabilization time ST is small between times t _{0 and} t ₁ , the change amount limit value α is 0, and R (n) is also the previous value R (n Continue to maintain -1). During the time t _{1 to} t ₂ , the change amount limit value α takes a constant value α1, while the difference between the left / right speed ratio RV _RL and the previous different diameter ratio R (n−1) is large. n) is a value obtained by adding α to the previous value R (n−1). Similarly, from time t _{2 to} t ₃ , R (n) maintains the previous value R (n−1) as in time t _{0 to} t _1, and from time t _{3 to} t ₅ , R (n) Is a value obtained by subtracting α1 from the previous value R (n−1). Further, after time t ₆ , R (n) is set to a value obtained by adding α1 to the previous value R (n−1), and the left-right speed ratio RV _RL is caused to follow the different diameter ratio R (n).

  As described above, in the different diameter ratio calculation unit 21 of the present embodiment, even if the vehicle CR turns, the value of the different diameter ratio R (n) is not significantly affected. An accurate value of the different diameter ratio R (n) can be obtained. Therefore, the vehicular brake hydraulic pressure control apparatus 100 in which the target hydraulic pressure is set and the inlet valve 1 and the outlet valve 2 are controlled based on the value of the different diameter ratio R (n) is also irrespective of the turning operation of the vehicle CR. Thus, it becomes possible to perform control as set.

Although the first embodiment of the present invention has been described above, the present invention can be implemented with appropriate modifications. For example, in the first embodiment, based on the lateral velocity ratio RV _RL, but multiplied by limiting the variation of the different diameter ratio R (n), the value of the left and right speed difference dVR _RL or lateral speed difference dVF _RL is given The amount of change in the different diameter ratio R (n) may be limited when it becomes larger than this value. Also be used left and right velocity ratio RV _RL, also be used left and right speed difference dVR _RL or lateral speed difference dVF _RL, only differences in the handling of numbers, but differences in technical meaning there is little, the left and right speed difference dVR _RL Alternatively, if the value of the left-right speed difference dVF _RL is used, it can be clearly determined that the left-right speed difference has increased regardless of the wheel speeds V _R , V _L. This is because even with the same left-right speed difference dVR _RL or left-right speed difference dFR _RL , the left-right speed ratio RV _RL becomes smaller at higher speeds, and there are disadvantages in calculation processing, such as an increase in the number of digits in calculation. . Therefore, in practice, it is desirable to limit the change of the different diameter ratio R (n) based on the left-right speed difference dVR _RL or the left-right speed difference dVF _RL .
Here, the predetermined value may be variable according to the wheel speeds V _R and V _L. Similarly in the first embodiment described above, the predetermined value may be variable according to the wheel speeds V _R and V _L.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
In the first embodiment, when the difference between the left / right speed ratio RV _RL and the previous different diameter ratio R (n−1) is large or when the stabilization time ST of the left / right speed ratio RV _RL is low, the previous different diameter ratio R ( n-1) is multiplied by the limit on the amount of change in current of the different diameter ratio R (n) for, in the present embodiment, with an emphasis on the value of the left and right velocity ratio RV _RL, lateral velocity ratio RV _RL predetermined value In the case where it is larger, a case will be described in which the amount of change in the current different diameter ratio R (n) with respect to the previous different diameter ratio R (n-1) is limited.

In the figure to refer, FIG. 7 is a block diagram showing the details of the different diameter ratio calculation unit of the brake fluid pressure control device according to the second embodiment. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
Since the brake hydraulic pressure control device of the present embodiment is the same as that of the first embodiment except for the different diameter ratio calculation unit 21 in the configuration shown in FIG. 3 of the first embodiment, the different diameter ratio calculation unit 21 (FIG. 7 will be described with a focus on the different diameter ratio calculating section 21 '.

  As shown in FIG. 7, the different diameter ratio calculation unit 21 ′ includes, as detailed functional units, a wheel speed calculation unit 21a, a left / right speed ratio calculation unit 21b, a change amount limit value setting unit 21d ′, and a left / right different diameter ratio calculation. A portion 21e is provided.

  The wheel speed calculator 21a and the left / right speed ratio calculator 21b are the same as in the first embodiment.

The change amount limit value setting unit 21d ′ sets a change amount limit value α, which is an upper limit value of the change amount of the different diameter ratio, in order to prevent excessive fluctuation of the calculated different diameter ratio R (n).
When the magnitude (absolute value) of RV _RL −1 is equal to or less than a predetermined value, the change amount limit value setting unit 21d ′ sets a large value α1 as the change amount limit value α, and is larger than the predetermined value. Is set to a value α2 smaller than α1. As this predetermined value, for example, as shown in FIG. 9, a constant left-right speed ratio threshold value TH _V2 can be taken. Of course, the left / right speed ratio threshold TH _V2 is not necessarily constant, and may be changed according to the wheel speeds V _R and V _L , or may be changed according to the stabilization time ST. The variation limit value α is output to the different diameter ratio calculation unit 21e.
In addition, “−1” of RV _RL −1 is obtained by subtracting the value “1” of the left / right speed ratio when both the left and right wheels have the same size.
Further, the change amount limit value setting unit 21d ′ determines that the different diameter ratio R when the magnitude (absolute value) of RV _RL −1 is larger than the magnitude (absolute value) of R (n−1) −1. Since (n-1) may be overestimated on the side where the difference between the diameters of both wheels is large, the variation limit value α is set to α1, which is a relatively large value.

As in the first embodiment, the left / right different diameter ratio calculation unit 21e calculates the left / right speed ratio RV _RL , the change amount limit value α, and the previous different diameter ratio R (n−1) stored in the storage unit 29. The current different diameter ratio R (n) is calculated.

The operation of the vehicle brake hydraulic pressure control apparatus 100 according to the second embodiment as described above will be described with reference to FIGS. 8 and 9. FIG. 8 is a flowchart for explaining the process of calculating the different diameter ratio of the vehicle brake hydraulic pressure control device according to the second embodiment, and FIG. 9 shows the vehicle brake hydraulic pressure control device according to the second embodiment. 5 is a timing chart showing temporal changes in a left / right speed ratio RV _RL (a) and a change amount limit value (b) during turning of a mounted vehicle. Note that in the chart of FIG. 9 (a), superimposed on a change of the left and right velocity ratio RV _RL shows the variation of the different diameter ratio R (n).

As shown in FIG. 8, first, the wheel speed calculation unit 21a calculates the wheel speeds V _L and V _R from the rotational speeds ω _L and ω _{R of} the left and right rear wheels detected by the wheel speed sensor 91 (S201). . Then, the left / right speed ratio calculation unit 21b calculates the left / right speed ratio RV _RL based on the equation (1) (S202).

Next, the change amount limit value setting unit 21d ′ determines whether or not the absolute value of the left / right speed ratio RV _RL is greater than the left / right speed ratio threshold TH _V2 (S203, No). Since there is a low possibility that the vehicle is turning, the change amount limit value α is set to α1, which is a relatively large value (S204). On the other hand, when the absolute value of the left / right speed ratio RV _RL is larger than the left / right speed ratio threshold TH _V2 (S203, Yes), the absolute value of the left / right speed ratio RV _RL is further calculated as the different diameter ratio R (n−1). It is judged whether it is larger (S205). If the absolute value of the left / right speed ratio RV _RL is not larger than the previously calculated different diameter ratio R (n−1) (No at S205), the vehicle CR is erroneously turned while the different diameter ratio R (n) is increased. Therefore, the variation limit value α is set to α1, which is a relatively large value (S204). On the other hand, if the absolute value of the left / right speed ratio RV _RL is larger than the previously calculated different diameter ratio R (n−1) (S205, Yes), there is a high possibility that the vehicle CR is turning, so the change amount is limited. The value α is set to α2, which is smaller than α1 (S206).

And right-and-left different diameter ratio calculation part 21e calculates different diameter ratio R (n) according to Steps S206-S210 like Steps S108-S112 of a 1st embodiment.
Therefore, as shown in FIGS. 9A and 9B, during the time t _{0 to} t ₁ , since the magnitude of the left / right speed ratio RV _RL is smaller than the left / right speed ratio threshold, the change amount limit value α is α1. Take. Time Then, R (n) is initially to follow following the lateral velocity ratio RV _RL, became the inclination of the left and right velocity ratio RV _RL increases faster than the increase due to the change amount limiting value α (= α1) From this, it increases by adding a constant value α1 to R (n−1).

Since the magnitude of the left / right speed ratio RV _RL is larger than the left / right speed ratio threshold TH _V2 between times t ₁ and t ₂ , the variation limit value α is set to α2 smaller than α1, and R (n− R (n) increases as α2 is added to 1).
Further, since the size of the right / left speed ratio RV _RL is smaller than the size of the different diameter ratio R (n−1) between the times t ₂ and t ₃ , the change amount limit value α is returned to α1, and R (n By subtracting α1 from -1), R (n) decreases.
When the left / right speed ratio RV _RL and the different diameter ratio R (n-1) coincide with each other at times t _{3 to} t ₄ , R (n) is calculated by R (n) according to the above equation (3). As a result, R (n) does not change. Similarly, at times t _{4 to} t ₅ , t _{5 to} t ₆ , and t _{6 to} t ₇ , α is set to α1 or α2, and R is increased or decreased by increasing or decreasing α to R (n−1). (N) is calculated, and the different diameter ratio R (n) is calculated as shown in FIG.

  As described above, in the different diameter ratio calculation unit 21 ′ of the present embodiment, even if the vehicle CR turns, the value of the different diameter ratio R (n) is not significantly affected. Accurate value of the different diameter ratio R (n) can be obtained. Therefore, the vehicular brake hydraulic pressure control apparatus 100 in which the target hydraulic pressure is set and the inlet valve 1 and the outlet valve 2 are controlled based on the value of the different diameter ratio R (n) is also irrespective of the turning operation of the vehicle CR. Thus, it becomes possible to perform control as set.

Although the second embodiment of the present invention has been described above, the present invention can be implemented with appropriate modifications. For example, the change amount limit value setting unit 21d ′ sets the change amount limit value α from α2 when the magnitude of RV _RL −1 is not greater than the magnitude of R (n−1) −1 as in step S205. Although a large α1 is set, the change amount limit value α may be set to α2 without making such a determination.
Also in the second embodiment, based on the left and right speed ratio RV _RL, instead of applying a limit to the amount of change in the different diameter ratio R (n), based on the values of the left and right speed difference dVR _RL or lateral speed difference dVF _RL Thus, the amount of change in the different diameter ratio R (n) may be limited.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
In the first embodiment, when the difference between the left / right speed ratio RV _RL and the previous different diameter ratio R (n−1) is large or when the stabilization time ST of the left / right speed ratio RV _RL is low, the previous different diameter ratio R ( In this embodiment, the change amount of the right / left speed ratio RV _RL is emphasized with emphasis on the change of the left / right speed ratio RV _RL . In the case where the magnitude is larger than a predetermined value, a case will be described in which the amount of change in the current different diameter ratio R (n) with respect to the previous different diameter ratio R (n−1) is limited.

In the figure to refer, FIG. 10 is a block diagram showing the details of the different diameter ratio calculation unit of the brake hydraulic pressure control device according to the third embodiment. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
Since the brake hydraulic pressure control device of the present embodiment is the same as that of the first embodiment except for the different diameter ratio calculation unit 21 in the configuration shown in FIG. 3 of the first embodiment, the different diameter ratio calculation unit 21 (FIG. 10 will be described focusing on the different diameter ratio calculating section 21 ″.

  As shown in FIG. 10, the different diameter ratio calculation unit 21 ″ includes, as detailed functional units, a wheel speed calculation unit 21a, a left / right speed ratio calculation unit 21b, a change rate calculation unit 21f, a change coefficient setting unit 21g, and a left / right different diameter. A ratio calculator 21e "is provided.

  The wheel speed calculator 21a and the left / right speed ratio calculator 21b are the same as in the first embodiment.

Change rate calculating unit 21f calculates the rate of change of the lateral velocity ratio RV _RL. That is, the left / right speed ratio RV _RL is differentiated to calculate the left / right speed ratio change rate dRV _RL . For example, the change rate of the left-right speed ratio RV _RL can be obtained by taking the difference between the left-right speed ratio RV _RL (n) calculated this time and the previously calculated left-right speed ratio RV _RL (n−1).

The change coefficient setting unit 21g sets a change coefficient k, which is an upper limit value of the change amount of the different diameter ratio, in order to prevent excessive fluctuation of the calculated different diameter ratio R (n).
The change coefficient setting unit 21g sets k1 as the change coefficient k when the magnitude of the change rate dRV _RL is equal to or smaller than a predetermined value, and sets 0 when larger than the predetermined value. As this predetermined value, for example, a constant change rate threshold TH _dRV can be taken as shown in FIG. Of course, the change rate threshold TH _dRV is not necessarily constant, and may be changed according to the wheel speeds V _R and V _L , or may be changed according to the stabilization time ST. The change coefficient k is output to the different diameter ratio calculation unit 21e ″.

The left / right different diameter ratio calculation unit 21e ″ multiplies the difference between the left / right speed ratio RV _RL and the different diameter ratio R (n−1) by the change coefficient k, that is, the different diameter ratio R (n) by the following equation (5). Is calculated.
R (n) = R (n−1) + k × (RV _RL −R (n−1)) (5)
In other words, when the rate of change of the left / right speed ratio RV _RL is large, the different diameter ratio R (n) maintains the previous value R (n−1), and when the rate of change of the left / right speed ratio RV _RL is small, reducing rate R (n) maintains the previous value R (n-1), to follow the left-right speed ratio RV _RL in accordance with the difference between the left and right velocity ratio RV _RL and different diameter ratio R (n-1) Go.

The operation of the vehicle brake hydraulic pressure control apparatus 100 according to the third embodiment as described above will be described with reference to FIGS. 11 and 12. FIG. 11 is a flowchart for explaining processing for calculating the different diameter ratio of the vehicle brake hydraulic pressure control device according to the third embodiment. FIG. 12 shows the vehicle brake hydraulic pressure control device according to the third embodiment. 5 is a timing chart showing temporal changes in a left-right speed ratio RV _RL (a), a change coefficient (b), and a left-right speed ratio change rate (c) during turning of a mounted vehicle. Note that in the chart of FIG. 12 (a), superimposed on a change of the left and right velocity ratio RV _RL shows the variation of the different diameter ratio R (n).

As shown in FIG. 11, first, the wheel speed calculation unit 21a calculates the wheel speeds V _L and V _R from the rotational speeds ω _L and ω _{R of} the left and right rear wheels detected by the wheel speed sensor 91 (S301). . Then, the left / right speed ratio calculation unit 21b calculates the left / right speed ratio RV _RL based on the equation (1) (S302).

Then, the change rate calculation unit 21f calculates the change rate dRV _RL (n) by subtracting the previous left / right speed ratio RV _RL (n−1) from the current left / right speed ratio RV _RL (n) (S303).

Next, the change coefficient setting unit 21g determines whether or not the magnitude (absolute value) of the change rate dRV _RL (n) is larger than the change rate threshold TH _dRV (S304, Yes). Since there is a high possibility that the CR is turning, the change coefficient k is set to 0 (S305). On the other hand, when the magnitude (absolute value) of the rate of change dRV _RL (n) is not larger than the rate of change threshold TH _dRV (No in S304), the change coefficient is low because the possibility that the vehicle CR is turning is low. k is set to k1 (S306).

Then, the left / right different diameter ratio calculation unit 21e ″ calculates the different diameter ratio R (n) according to the equation (5).
In this way, in the vehicle brake hydraulic pressure control device 100 of the present embodiment, as shown in FIG. 12B, the times t _{0 to} t ₁ , t _{2 to} t ₃ , t _{4 to} t ₅ , t _{6 are obtained.} After t ₇ and t _8, since the magnitude of the change amount dRV _RL is smaller than the change amount threshold TH _dRV , the change coefficient k takes k1. However, since the magnitude of the change rate dRV _RL is smaller than the change amount threshold TH _{dRV at} times t _{1 to} t ₂ , t _{3 to} t ₄ , t _{5 to} t ₆ , and t _{7 to} t ₈ , the change coefficient k is 0. Therefore taking, different diameter ratio R (n), when the variation coefficient k is k1 is slowly follows the lateral velocity ratio RV _RL, when the change coefficient k is 0, the previous value R (n-1) Maintaining no change.

  As described above, in the different diameter ratio calculation unit 21 ″ of the present embodiment, even if the vehicle CR turns, the value of the different diameter ratio R (n) is not significantly affected. Therefore, the inlet valve 1 and the outlet valve 2 are controlled by setting the target hydraulic pressure based on the value of the different diameter ratio R (n). The vehicle brake fluid pressure control device 100 can also perform the control as set regardless of the turning operation of the vehicle CR.

Although the third embodiment of the present invention has been described above, the present invention can be implemented with appropriate modifications. For example, the change coefficient setting unit 21g sets the change coefficient k to 0 when the change rate dRV _RL is larger than the change rate threshold TH _dRV , but may set it to k2 smaller than k1.
Further, by using the change coefficient k as a change amount limit value like the change amount limit value α of the first and second embodiments, for example, according to steps S107 to S112 in FIG. ) Can also be calculated.

It is a lineblock diagram of vehicles provided with a brake fluid pressure control device for vehicles concerning a 1st embodiment. It is a brake fluid pressure circuit diagram of the brake fluid pressure control device for vehicles concerning a 1st embodiment. It is a block block diagram of the brake hydraulic pressure control apparatus which concerns on 1st Embodiment. It is a block block diagram which shows the detail of a different diameter ratio calculation part. It is a flowchart explaining the process of calculation of the different diameter ratio of the brake fluid pressure control apparatus for vehicles which concerns on 1st Embodiment. Changes in the left-right speed ratio RV _RL (a), stability time ST (b), and variation limit value (c) over time when a vehicle equipped with the vehicle brake hydraulic pressure control device according to the first embodiment is turned. It is the timing chart shown. It is a block block diagram which shows the detail of the different diameter ratio calculation part of the brake fluid pressure control apparatus which concerns on 2nd Embodiment. It is a flowchart explaining the process of calculation of the different diameter ratio of the brake fluid pressure control apparatus for vehicles which concerns on 2nd Embodiment. 12 is a timing chart showing temporal changes in the left-right speed ratio RV _RL (a) and the change amount limit value (b) when the vehicle equipped with the vehicle brake hydraulic pressure control device according to the second embodiment is turned. It is a block block diagram which shows the detail of the different diameter ratio calculation part of the brake fluid pressure control apparatus which concerns on 3rd Embodiment. It is a flowchart explaining the process of calculation of the different diameter ratio of the brake fluid pressure control apparatus for vehicles which concerns on 3rd Embodiment. Temporal changes in the left-right speed ratio RV _RL (a), the change coefficient (b), and the change ratio (c) in the left-right speed ratio when the vehicle equipped with the vehicle brake hydraulic pressure control device according to the third embodiment is turned. It is the timing chart which showed.

Explanation of symbols

1 Inlet Valve 2 Outlet Valve TH _V1 Stability Range Threshold TH _V2 Left / Right Speed Ratio Threshold 10 Hydraulic Unit 10a Pump Body 20 Controller 21 Different Diameter Ratio Calculation Unit 91 Wheel Speed Sensor 100 Vehicle Brake Fluid Pressure Controller CR Vehicle FL Wheel Brake k change coefficient R diameter ratio RV _HOLD stabilization time reference value RV _RL left / right speed ratio ST stability time TH _ST stabilization time threshold TH _dRL change amount threshold TH _dRV change rate threshold V wheel speed dR _VRL change rate dVF _RL , dVR _RL left / right speed Difference α Change limit value

Claims (3)

Based on the left and right wheel speeds continuously detected by the wheel speed sensor for detecting the wheel speeds of the left and right wheels arranged on the same axis, a method for calculating the different diameter ratio of the left and right wheels,
Obtaining the wheel speed of each of the left and right wheels;
A step of calculating a different diameter ratio based on a ratio of wheel speeds of the left and right wheels,
When the difference between the wheel speeds of the left and right wheels or the change rate of the difference is greater than a predetermined value, the change of the different diameter ratio calculated this time with respect to the value of the different diameter ratio calculated last time is limited. The method of calculating the different diameter ratio of wheels. A device that calculates the different diameter ratio of the left and right wheels based on the left and right wheel speeds continuously detected by a wheel speed sensor that detects the wheel speeds of the left and right wheels arranged coaxially,
Having a different diameter ratio calculation unit for calculating a different diameter ratio based on a ratio of wheel speeds of the left and right wheels;
When the difference between the left and right wheel speeds or the change rate of the difference is greater than a predetermined value, the difference diameter ratio calculation unit limits the change in the difference diameter ratio calculated this time with respect to the previously calculated difference diameter ratio value. An apparatus for calculating a different diameter ratio of a wheel.   3. The wheel different diameter ratio according to claim 2, wherein the different diameter ratio calculation unit tightens the restriction on the change of the different diameter ratio when the wheel speed ratio stabilization time is shorter than when the wheel speed ratio is stable. Computing device.

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