JP3290457B2 - Vehicle body speed detection device - 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 speed detecting device for detecting a vehicle speed required for determining a slip ratio of a wheel in a traction control system or an anti-lock brake system.

[0002]

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

Slip ratio = (wheel speed−vehicle speed) / wheel speed × 10
0 By the way, in a vehicle equipped with a traction control system, when calculating the slip ratio of the drive wheels,
The average value of the left and right driven wheel speeds is used as the wheel speed, the average value of the left and right driven wheel speeds is used as the vehicle body speed, and the average value of the drive wheel speed and the average value of the driven wheel speed are calculated based on the above equation. A device that calculates a slip ratio of a driving wheel is known (for example, see Japanese Patent Application Laid-Open No. 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, although the correct vehicle body speed can be obtained when the vehicle is traveling straight, the vehicle is not driven when the vehicle turns. When the wheels and the driven wheels draw different trajectories, a speed difference is generated between the driving wheels and the driven wheels, so that a correct vehicle speed corresponding to the position of the driving wheels cannot be obtained. That is, although the vehicle speed corresponding to the position of the drive wheel should be used to calculate the slip ratio of the drive wheel, when the vehicle speed is obtained from the driven wheel speed that draws a different trajectory from the drive wheel when turning, an error occurs. Will occur. In particular, when the vehicle turns at a low speed, since the trajectories of the driving wheels and the driven wheels are greatly different from each other, the error of the vehicle body speed increases, so that there is a problem that it is impossible to calculate an accurate slip ratio of the driving wheels.

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

[0006]

In order to achieve the above object, a vehicle speed detecting apparatus for a vehicle according to the present invention comprises a driven wheel speed detecting means for detecting left and right driven wheel speeds, and a driven wheel speed detecting means. and a driven wheel speed average value calculating means for calculating a follower wheel speed average value based on the output, a steering angle detection means for detecting a steering angle of the vehicle, and a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle, the slave Wheel speed average and steering
Correction value calculating means for calculating a correction value of the average value of the driven wheel speed based on the steering angle detected by the angle detecting means, and a vehicle body based on the correction value calculated by the average value of the driven wheel speed and the correction value calculating means. Vehicle speed calculating means for calculating the speed , wherein the calculation of the correction value is performed when the average value of the driven wheel speed is a predetermined value.
Value and the lateral acceleration is smaller than a predetermined value.
It is characterized by being performed when

[0007]

EXAMPLES 1 to 4 show an embodiment in which the present invention is applied to a vehicle traction control system,
Figure 1 is a schematic structural diagram of the vehicle, a flowchart shown in FIG. 2 is a block diagram of a traction control system, Figure 3 is a block diagram showing the circuit configuration of the electronic control unit, Figure 4 the effect of the actual施例.

As shown in FIG. 1, this vehicle is a front-wheel drive vehicle, and includes 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 _FL
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.
_{Are provided} with a pair of left and right driven wheel speed detecting means 2 _RL , 2 _RR for detecting driven wheel speeds V _RL , V _RR .

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

FIG. 2 shows that the signals from the respective detecting means are arithmetically processed based on a control program in order to suppress the excessive slip of the driving wheels W _FL and W _FR , and the throttle valve 8 is driven by the pulse motor 7. 1 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 the control program and data such as various tables.
12, a random access memory (RAM) 13 for temporarily storing a detection signal and a calculation result of each of the detectors, and each of the detection means, that is, the drive wheel speed detection means _1FL , _1FR , and the driven wheel speed detection means _2RL. , 2 _RR , an input unit 14 to which the steering angle detecting means 4 and the lateral acceleration detecting means 5 are connected, and an output unit 15 to which the pulse motor 7 is connected. Thus, the electronic control unit U receives various signals input from the input unit 14 and the read only memory 1.
The central processing unit 11 performs arithmetic processing on the data and the like stored in 2 based on a control program described later, and finally drives the pulse motor 7 via the output unit 15. This gives
The throttle valve 8 is controlled to change the output torque of the internal combustion engine E. As a result, the drive wheel torque is controlled to an optimum value 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.
Will be described.

The left and right driving wheel speeds V _FL , V _FR detected by the left and right driving wheel speed detecting means 1 _FL , 1 _FR are inputted to the driving wheel speed average value calculating means 21, where the two driving wheel speeds V _FL , V _FR are obtained. By calculating the average value of _FR (V _FL + V _FR ) / 2, the driving wheel speed average value Vw is obtained. Further, the left and right follower wheel speed detecting means 2 _RL, 2 _RR left and right follower wheel speed V _RL detected by, V _RR is the follower wheel speed average value calculating means 22
, _Where the average value (V _RL + V _RR ) / 2 of the driven wheel speeds V _RL and V _RR is calculated to obtain the driven wheel speed average value Vv.

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

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

[0015] 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
(V _RL + V _RR ) / 2, that is, the average value of the driven wheel speed Vv is a predetermined value (for example, 60 km /
h). In step S1, the driven wheel speed average value V
If v is smaller 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, 0.5 G) in the following step S2. If the lateral acceleration G is less than the predetermined value in step S2, the following driven wheel speed average value Vv is multiplied by a constant K in step S3 to obtain a value corresponding to the speed difference between the front and rear wheels of the vehicle during turning. The correction value ΔVv is obtained. The constant K is a value retrieved from a table based on the steering angle δ and the average value of the driven wheel speed Vv. Finally, in step S4, the final vehicle speed Vv is obtained by adding the correction value ΔVv to the driven wheel speed average value Vv.

As described above, the process of obtaining the vehicle speed Vv by adding the correction value ΔVv to the average value of the driven wheel speed Vv is performed when the average value of the driven wheel speed Vv is smaller than the predetermined value and the lateral acceleration G is set to the predetermined value. It is done when less than. This is because the turning radius of the vehicle increases during high-speed running and the speed difference due to the difference in the trajectory of the front and rear wheels decreases, and the lateral acceleration G
Is larger, the slip angle of the vehicle body increases, and the speed difference due to the difference between the trajectories of the front and rear wheels decreases. Thus, the speed difference between the front and rear wheels is obtained as a correction value ΔVv at a low speed and low lateral acceleration at which the speed difference between the front and rear wheels becomes large, and the correction value ΔVv is added to the average value of the driven wheel speed Vv, whereby the drive wheel W _FL , correct vehicle speed corresponding to the position of the W _FR Vv
Is required.

Returning to FIG. 3, the driving wheel speed average value calculating means 2
1 and the vehicle speed calculating means 2
4 the vehicle speed Vv determined in 'is input to the slip rate calculating means 25, where the drive wheels W _FL, the slip ratio of the W _FR, slip ratio = (Vw-Vv' obtained by) / Vw × 100. When the slip ratio of the drive wheels W _FL , W _FR exceeds a predetermined value, the electronic control unit U drives the pulse motor 7 to control the closing of the throttle valve 8, thereby reducing the output torque of the internal combustion engine E. reduced to driving wheels W _FL, that to prevent excessive slipping of W _FR.

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

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

[0020]

As described above, according to the present invention, high-speed running
In the middle, the turning radius of the vehicle increases and
Speed difference is small, and when the lateral acceleration is large,
Increased slip angle of the body due to the difference in trajectory between the front and rear wheels
Considering that the speed difference becomes smaller, the average value of the driven wheel speed
Smaller than a predetermined value and the lateral acceleration is smaller than a predetermined value.
(I.e., the speed difference between the front and rear wheels during turning is large)
Driven wheel speed only at low speeds and low lateral accelerations)
A correction value for the average value of the driven wheel speed is calculated based on the average degree value and the steering angle, and the average value of the driven wheel speed is corrected with the correction value to calculate a vehicle speed corresponding to the position of the drive wheel. Therefore, when turning, the driving wheel and the driven wheel draw different trajectories.
(Especially at low speed and low lateral acceleration.
That) to compensate for errors, it is possible to obtain an accurate vehicle speed, therefore, drive the exact vehicle speed obtained in this manner
The drive wheel speed is specifically corrected based on the comparison with the wheel speed.
It is possible to accurately and accurately determine the slip state even without
You .

Further, the calculation of the correction value is based on the average of the driven wheel speeds.
The calculation of the vehicle speed is based on the value and the steering angle.
Based on the average wheel speed and the above correction value,
In addition to simple operation, turning
When turning (that is, when turning at high speed or high lateral acceleration),
Computation of such correction values can be omitted, so the computation
Simplification of the process, which saves equipment costs and processes
This can contribute to speeding up.

[Brief description of the 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 flow chart of the vehicle speed detection

[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 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

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Osamu Yamamoto 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside of Honda R & D Co., Ltd. (72) Inventor Shuji Shiroishi 1-4-1 Chuo, Wako-shi, Saitama pref. (56) References JP-A-2-227338 (JP, A) JP-A-64-32955 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60T 8 / 58

Claims (1)

(57) [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) Driven wheel speed average value calculating means (22) for calculating a driven wheel speed average value (Vv) based on the vehicle speed; and steering angle detecting means (4) for detecting a vehicle steering angle (δ).
A lateral acceleration detecting means (5) for detecting a lateral acceleration (G) of the vehicle, and a mean value (Vv) of the driven wheel speed and a steering angle detecting means.
Correction value calculating means (23) for calculating a correction value (ΔVv) of the average value of the driven wheel speed (Vv) based on the steering angle (δ) detected in (3); and the average value of the driven wheel speed (Vv) And correction value calculating means
Vehicle speed calculating means (24) for calculating a vehicle speed (Vv ') based on the correction value (.DELTA.Vv) calculated in (23) , wherein the calculation of the correction value (.DELTA.Vv) is value
(Vv) is smaller than a predetermined value and the lateral acceleration
(G) is characterized by being performed when less than the predetermined value, the vehicle speed detection equipment of the vehicle.