JPH05208669A - Car body speed detecting device for vehicle - Google Patents

Abstract

PURPOSE:To correct a driven wheel speed so as to obtain an accurate car body speed corresponding to A drive wheel speed by considering a locus difference between drive and driven wheels at the time of turning a vehicle. CONSTITUTION:Based on a driven wheel speed mean value Vv obtained by a driven wheel speed mean value arithmetic means 22 from driven wheel speeds VRR, VRL output by right/left driven wheel speed detecting means 2RR, 2RL, steering angle delta output by a steering angle detecting means 4 and cross acceleration G output by a cross acceleration detecting means 5, a correction value DELTAVv corresponding to a speed difference between drive and driven wheels at turning time is obtained by a correction value arithmetic means 23, and by adding this correction value DELTAVv to the driven wheel speed mean value Vv in a car body speed arithmetic means 24, a car body speed Vv' is obtained. Since this car body speed Vv' is corrected so as to correspond to a position of the drive wheel, accuracy is improved in the case of calculating a slip rate of the drive wheel from a drive wheel speed mean value Vw and the car body speed Vv' by a slip rate arithmetic means 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body speed detecting device for a vehicle for detecting a vehicle body speed necessary for obtaining a slip ratio of a wheel in a traction control system or an antilock brake system.

[0002]

2. Description of the Related Art In a vehicle equipped with a traction control system for preventing excessive slip of the wheels at the time of starting or during sudden acceleration, and a vehicle equipped with an anti-lock brake system for preventing the locking of the wheels during braking. The wheel slip ratio is calculated based on the following equation.

Slip rate = (wheel speed-vehicle body speed) / wheel speed × 100 By the way, in a vehicle equipped with a traction control system, when calculating the slip rate of the driving wheels,
While using the average value of the left and right drive wheel speeds as the wheel speed, using the average value of the left and right driven wheel speeds as the vehicle body speed, based on the above equation from the drive wheel speed average value and the driven wheel speed average value. It is known to calculate the slip ratio of the driving wheels (see, for example, JP-A-61-60331).

[0004]

However, in the above-mentioned conventional method using the average value of the left and right driven wheel speeds as the vehicle body speed, the correct vehicle body speed can be obtained when the vehicle travels straight, but the vehicle is driven when turning. Since different speeds are generated between the drive wheel and the driven wheel by drawing different trajectories of the wheel and the driven wheel, it is not possible to obtain the correct vehicle body speed corresponding to the position of the drive wheel. That is, the vehicle body speed corresponding to the position of the driving wheel should be used to calculate the slip ratio of the driving wheel, but when the vehicle body speed is obtained from the driven wheel speed that draws a different trajectory from the driving wheel at the time of turning, an error occurs. Will occur. In particular, since the trajectories of the driving wheels and the driven wheels are greatly different during low-speed turning, there is a problem in that the error in the vehicle body speed increases and the accurate slip ratio of the driving wheels cannot be calculated.

The present invention has been made in view of the above circumstances, and provides a vehicle body speed detecting device for a vehicle capable of obtaining an accurate vehicle body speed corresponding to the position of the drive wheels even when the vehicle is turning. With the goal.

[0006]

In order to achieve the above object, a vehicle body speed detecting device for a vehicle according to the present invention comprises a driven wheel speed detecting means for detecting left and right driven wheel speeds, respectively, and this driven wheel speed detecting means. Driven wheel speed average value calculation means for calculating the driven wheel speed average value based on the output of the vehicle, steering angle detection means for detecting the steering angle of the vehicle, lateral acceleration detection means for detecting the lateral acceleration of the vehicle, and A correction value calculating means for calculating a correction value of the driven wheel speed average value based on the outputs of the steering angle detecting means and the lateral acceleration detecting means, and a vehicle body for calculating a vehicle body speed based on the driven wheel speed average value and the correction value. And a speed calculation means.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment in which the present invention is applied to a traction control system for a vehicle. FIG. 1 is a schematic configuration diagram of the vehicle, FIG. 2 is a block diagram of the traction control system, and FIG. 3 is a block diagram showing the circuit configuration of the electronic control unit, and FIG. 4 is a flow chart showing the operation of the first embodiment.

As shown in FIG. 1, this vehicle is a front-wheel drive vehicle, and has a pair of left and right drive wheels W _FL and W _FR driven by an internal combustion engine E and a pair of left and right driven wheels W _RL and W _RR . And each drive wheel W _FL , W _FR has a drive wheel speed V _FL , V
_A pair of left and right driving wheel speed detecting means 1 _FL , 1 _{FR for} detecting _FR is provided and each driven wheel W _RL , W _RR.
Is provided with a pair of left and right driven wheel speed detection means 2 _RL and 2 _RR for detecting the driven wheel speeds V _RL and V _RR .

The steering wheel 3 is provided with steering angle detection means 4 for detecting the steering angle δ, and
Lateral acceleration detecting means 5 for detecting the lateral acceleration G at the time of turning is provided at a proper position of the vehicle body. Further, the intake passage 6 of the internal combustion engine E is provided with a throttle valve 8 which is connected to a pulse motor 7 and driven to open and close. The driving wheel speed detecting means 1 _FL , 1 _FR and the driven wheel speed detecting means 2 _{RL are provided.} , 2
_{The RR} , steering angle detecting means 4, lateral acceleration detecting means 5, and pulse motor 7 are connected to an electronic control unit U equipped with a microcomputer.

In FIG. 2, in order to suppress the excessive slip of the drive wheels W _FL and W _FR , the signals from the respective detecting means are arithmetically processed based on a control program, and the pulse motor 7 drives the throttle valve 8. 2 shows an electronic control unit U for controlling the output torque of the internal combustion engine E. The electronic control unit U includes a central processing unit (CPU) 11 for performing the arithmetic processing, a read only memory (ROM) storing data such as the control program and various tables.
12, random access memory (RAM) 13 for temporarily storing detection signals and calculation results of each detector, each detecting means, that is, driving wheel speed detecting means 1 _FL , 1 _FR , driven wheel speed detecting means 2 _RL , 2 _RR , steering angle detecting means 4, and lateral acceleration detecting means 5 are connected to the input section 14, and the pulse motor 7 is connected to the output section 15. Thus, the electronic control unit U includes various signals input from the input section 14 and the read-only memory 1
The data and the like stored in 2 are arithmetically processed by the central processing unit 11 based on a control program described later, and finally the pulse motor 7 is driven via the output unit 15. This allows
The throttle valve 8 is controlled to change the output torque of the internal combustion engine E, and as a result, the drive wheel torque is controlled to an optimum value in order to suppress excessive slip of the drive wheels W _FL and W _FR of the vehicle.

Next, the electronic control unit U will be described with reference to FIG.
The circuit configuration of will be described.

Left and right drive wheel speed detection means 1_FL, 1_FRBy
Left and right drive wheel speed V detected_FL, V_FRIs the drive wheel speed flat
It is input to the average value calculation means 21, and the speed of both drive wheels
V_FL, V _FRAverage value of (V_FL+ V_FR) / 2 is calculated
Thus, the drive wheel speed average value Vw is obtained. Also, left and right
Driven wheel speed detection means 2_RL, 2_RRLeft and right detected by
Driven wheel speed V_RL, V_RRIs a driven wheel speed average value calculation means 22.
To the driven wheel speed V_RL, V_RRAverage value of
(V_RL+ V_RR) / 2 is calculated to calculate the speed of the driven wheel
The average value Vv is obtained.

On the other hand, the steering angle δ of the steering wheel 3 detected by the steering angle detection means 4 and the lateral acceleration G detected by the lateral acceleration detection means 5 are input to the correction value calculation means 23, and the correction value ΔVv calculated there is calculated. It is input to the vehicle body speed calculation means 24 together with the driven wheel speed average value Vv calculated by the driven wheel speed average value calculation means 22. Then, the vehicle body speed calculating means 24 calculates the vehicle body speed Vv 'based on the average value Vv of the driven wheels and the correction value ΔVv.

Next, based on the flowchart of FIG.
The contents of the programs executed by the correction value calculation means 23 and the vehicle body speed calculation means 24 will be described.

[0016] First, the follower wheel speed detecting means in Step S1 2 _RL, 2 driven left and right detected by _RR wheel speeds V _RL, V _RR
Average value (V _RL + V _RR ) / 2, that is, the driven wheel speed average value Vv is a predetermined value (for example, 60 km /
h). In step S1, the average driven wheel speed V
If v is less than the predetermined value, the lateral acceleration G of the vehicle body detected by the lateral acceleration detecting means 5 is compared with a predetermined value (for example, 0.5G) set in advance in step S2. If the lateral acceleration G is less than the predetermined value in step S2, it is a value corresponding to the speed difference between the front and rear wheels of the vehicle at the time of turning by multiplying the driven wheel speed average value Vv by a constant K in subsequent step S3. The correction value ΔVv is obtained. The constant K is a value retrieved from the table based on the steering angle δ and the average driven wheel speed value Vv. Finally, in step S4, the final vehicle speed Vv is obtained by adding the correction value ΔVv to the average driven wheel speed Vv.

As described above, in the processing for obtaining the vehicle body speed Vv by adding the correction value ΔVv to the driven wheel speed average value Vv, the driven wheel speed average value Vv is smaller than a predetermined value and the lateral acceleration G is a predetermined value. It is done when smaller than. This is because the turning radius of the vehicle becomes large and the speed difference due to the difference in the trajectories of the front and rear wheels becomes small when the vehicle runs at high speed.
This is because the slip angle of the vehicle body increases and the speed difference due to the difference in the trajectories of the front and rear wheels becomes smaller when is larger. Thus, when the speed difference between the front and rear wheels is low and the lateral acceleration is low, the speed difference between the front and rear wheels is obtained as the correction value ΔVv, and the correction value ΔVv is added to the average value Vv of the driven wheels to drive the drive wheel W _FL. , V _FR corresponding to the position of W _FR
Is required.

Returning to FIG. 3, the driving wheel speed average value calculating means 2
Driving wheel speed average value Vw obtained in 1 and vehicle speed calculation means 2
The vehicle body speed Vv ′ obtained in step 4 is input to the slip ratio calculating means 25, where the slip ratios of the drive wheels W _FL and W _FR are calculated by slip ratio = (Vw−Vv ′) / Vw × 100. When the slip ratios of the drive wheels W _FL , W _FR exceed a predetermined value, the electronic control unit U drives the pulse motor 7 to control the closing of the throttle valve 8 to control the output torque of the internal combustion engine E. Reduced to prevent excessive slip of the drive wheels W _FL and W _FR .

5 to 7 show a second embodiment of the present invention. FIG. 5 is a flow chart corresponding to FIG. 4, and FIG.
Is a graph showing the relationship between the steering angle δ and the correction value ΔVv, and FIG. 7 is a graph showing the relationship between the lateral acceleration G and the correction value ΔVv.

In this embodiment, the driven wheel speed average value Vv obtained by the driven wheel speed average value calculating means 22 in step S11.
Based on the lateral acceleration G detected by the lateral acceleration detecting means 5 and the steering angle δ of the steering wheel 3 detected by the steering angle detecting means 4, a correction value corresponding to the speed difference between the front and rear wheels of the vehicle at the time of turning. ΔVv is calculated. That is, the steering angle δ and the correction value ΔVv when the lateral acceleration G is constant.
(See FIG. 6) and the relationship between the lateral acceleration G and the correction value ΔVv (see FIG. 7) when the steering angle δ is constant (see FIG. 7) are stored in advance in the read-only memory 12 as a table. The correction value ΔVv is obtained from the velocity average value Vv. Then, in step S12, the vehicle body speed Vv 'is obtained by adding the correction value ΔVv to the average driven wheel speed value Vv.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various small design changes can be made.

For example, in the embodiment, the front wheel drive vehicle in which the front wheels are the drive wheels and the rear wheels are the driven wheels has been exemplified, but the present invention is applied to the rear wheel drive vehicle in which the front wheels are the driven wheels and the rear wheels are the drive wheels. It can also be applied. Further, the present invention is not limited to the traction control system, but can be applied to other applications such as an antilock brake system.

[0023]

As described above, according to the present invention, the correction value of the average driven wheel speed value is calculated based on at least the steering angle of the vehicle and the lateral acceleration of the vehicle, and the average value of the driven wheel speed is calculated using this correction value. Since the vehicle speed corresponding to the position of the drive wheel is calculated by correcting the error, it is possible to obtain an accurate vehicle speed by compensating for the error caused by drawing different trajectories of the drive wheel and the driven wheel during turning. ..

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a vehicle including a traction control system.

FIG. 2 is a block diagram of a traction control system.

FIG. 3 is a block diagram showing a circuit configuration of an electronic control unit.

FIG. 4 is a flowchart of vehicle body speed detection.

5 is a flowchart corresponding to FIG. 4 according to the second embodiment of the present invention.

FIG. 6 is a graph showing a relationship between a steering angle δ and a correction value ΔVv.

FIG. 7 is a graph showing the relationship between lateral acceleration G and correction value ΔVv.

[Explanation of symbols]

2 _RL , 2 _RR driven wheel speed detection means 4 steering angle detection means 5 lateral acceleration detection means 22 driven wheel speed average value calculation means 23 correction value calculation means 24 vehicle body speed calculation means V _RL , V _RR driven wheel speed Vv driven wheel speed Average value ΔVv Correction value Vv ′ Body speed δ Steering angle G Lateral acceleration

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[Procedure amendment]

[Submission date] January 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Slip rate = [ (wheel speed-vehicle speed) /
Car body Speed] × 100 Incidentally, in a vehicle equipped with a traction control system, when calculating the slip ratio of the driving wheels,
While using the average value of the left and right drive wheel speeds as the wheel speed, using the average value of the left and right driven wheel speeds as the vehicle body speed, based on the above equation from the drive wheel speed average value and the driven wheel speed average value. It is known to calculate the slip ratio of the driving wheels (see, for example, JP-A-61-60331).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

As described above, the driven wheel speed average value Vv is supplemented.
The process of adding the positive value ΔVv to obtain the vehicle body speed Vv is
The driving wheel speed average value Vv is smaller than a predetermined value, and lateral acceleration is performed.
It is performed when the degree G is smaller than a predetermined value. This is high speed
When traveling, the turning radius of the vehicle becomes large and the difference in the trajectories of the front and rear wheels
The speed difference due toSmall as a percentage of vehicle speedFor
And when the lateral acceleration G increases, the vehicle body slips.
The angle increases and the speed difference due to the difference between the front and rear wheels is small
This is because Therefore, the speed difference between the front and rear wheels becomes large.
Correction value ΔV for the difference in speed between the front and rear wheels at low and low lateral acceleration
v, and the correction value ΔVv is the average value V of the driven wheels.
drive wheel W by adding to v_FL, W _FRCorresponding to the position
The correct vehicle body speed Vv is calculated.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Returning to FIG. 3, the driving wheel speed average value calculating means 2
Driving wheel speed average value Vw obtained in 1 and vehicle speed calculation means 2
The vehicle body speed Vv ′ obtained in step 4 is input to the slip ratio calculating means 25, where the slip ratios of the drive wheels W _FL and W _FR are calculated by slip ratio = [ (Vw−Vv ′) / Vv ′] × 100. .. When the slip ratios of the drive wheels W _FL , W _FR exceed a predetermined value, the electronic control unit U drives the pulse motor 7 to control the closing of the throttle valve 8 to control the output torque of the internal combustion engine E. Reduced to prevent excessive slip of the drive wheels W _FL and W _FR .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Yamamoto 1-4-1, Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor, Master Shiroishi 1-4-1, Wako-shi, Saitama Prefecture Stock Company Honda Technical Research Institute

Claims (1)

[Claims] 1. A left and right follower wheel speed (V _RL, V _RR) and a driven wheel speed detecting means for detecting each (2 _RL, 2 _RR), the output of the follower wheel speed detecting means (2 _RL, 2 _RR) The driven wheel speed average value (Vv) is calculated on the basis of the driven wheel speed average value (Vv), the steering angle detection means (4) for detecting the steering angle (δ) of the vehicle, and the lateral acceleration of the vehicle ( G) for detecting the lateral acceleration, and based on the outputs of at least the steering angle detecting means (3) and the lateral acceleration detecting means (4), the correction value (ΔV) of the average value (Vv) of the driven wheel speeds.
v) and a vehicle speed calculation means (2) for calculating a vehicle speed (Vv ') based on the driven wheel speed average value (Vv) and the correction value (ΔVv).
4) A vehicle body speed detecting device for a vehicle, comprising: