JPH061223A - Estimated vehicle speed computing device - Google Patents

Abstract

PURPOSE:To estimate the vehicle speed in a simple manner and with a high accuracy by providing an estimated vehicle speed computing means where the estimated vehicle acceleration is successively updated by the preset acceleration/deceleration, and when the acceleration/deceleration is judged, the estimated vehicle speed is obtained by successively updating the current estimated vehicle speed by the vehicle acceleration/deceleration. CONSTITUTION:When a judgement is made that the vehicle acceleration/ deceleration Gx is not less than the specified value alpha in an acceleration/ deceleration discriminating circuit 37, or when the control signal S based on the braking operation and the acceleration operation of a driver is supplied to the acceleration/deceleration discriminating circuit 37, a judgement is made that the vehicle is accelerated/decelerated and the method to obtain the estimated vehicle speed Vref(n) is switched by using the expression I. (where, t means the computing period). Thus, the estimated vehicle speed Vref(n) can be obtained with high accuracy by using the value of the vehicle acceleration/ deceleration Gx.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an estimated vehicle body speed calculating apparatus for calculating a vehicle body speed of a vehicle from wheel speeds and vehicle body acceleration / deceleration.

[0002]

2. Description of the Related Art In automobiles and motorcycles, a so-called brake control device is used which controls the wheel speed of a vehicle being braked by comparing it with the vehicle speed. In this brake control device, the slip ratio is obtained from the wheel speed and the vehicle body speed, and when the slip ratio exceeds the target slip ratio, the brake fluid pressure is reduced to control the wheel speed and reduce the slip ratio. To obtain the optimum braking force.

Further, there is a driving force control device for controlling the driving force by adjusting the ignition timing of the engine in response to a sudden start or a change in the road surface friction coefficient. Also in this driving force control device, the wheel speed and the vehicle body speed are used for control.

By the way, the wheel speed can be directly detected by the sensor from the rotational speed of the wheel, but it is difficult to directly detect the vehicle speed by the sensor. Not practically possible with vehicles that are significantly limited in size. Therefore, the vehicle body speed is usually estimated from the wheel speed or the vehicle body acceleration / deceleration.

In this case, a method of selecting the wheel speed of the wheel that rotates the fastest among a plurality of wheels to obtain the estimated vehicle speed (Japanese Patent Laid-Open No. 63-78867) (hereinafter referred to as Hi-sel).
ect method), a method of integrating and obtaining the vehicle body acceleration / deceleration detected by the vehicle body acceleration / deceleration detector (JP-A-63
No. 24166), or a method of comparing the wheel speed with the current estimated vehicle body speed and updating the estimated vehicle body speed at a constant acceleration / deceleration based on the comparison result.

[0006]

However, in a situation where the wheels slip with respect to the road surface, the estimated vehicle body speed may be set higher than the actual vehicle body speed. In this case, when a slip state occurs at the time of starting the vehicle, the control by the brake control device or the driving force control device may become inappropriate in the Hi-select method. Further, in the method of integrating the detected vehicle body acceleration / deceleration to obtain the estimated vehicle body speed, noise may be mixed in the vehicle body acceleration / deceleration due to vibration of the vehicle body based on road surface conditions and the like. Therefore, when the vehicle body acceleration / deceleration is integrated and updated, noise may also be integrated and the estimated vehicle body speed may deviate from the actual vehicle body speed. Further, in the method of obtaining the vehicle body speed using a predetermined acceleration / deceleration, it is necessary to switch the set predetermined acceleration / deceleration between a road surface with low friction (low μ) and a road surface with high friction (high μ). There is complexity.

The present invention has been made in order to solve this kind of problem, and is an estimated vehicle body speed calculation capable of estimating the vehicle body speed required for brake control, driving force control, etc. easily and highly accurately. The purpose is to provide a device.

[0008]

In order to achieve the above-mentioned object, the present invention is an estimated vehicle body speed calculation apparatus for calculating an estimated vehicle body speed from a wheel speed and a vehicle body acceleration / deceleration, and a wheel for detecting the wheel speed. Based on a speed detection means, a vehicle body acceleration / deceleration detection means for detecting the vehicle body acceleration / deceleration, and an acceleration / deceleration signal or a predetermined control signal from the vehicle body acceleration / deceleration detection means, it is determined whether or not the vehicle body is in an acceleration / deceleration state. When the acceleration / deceleration determining means determines that the vehicle is not in the acceleration / deceleration state, the wheel speed is compared with the current estimated vehicle body acceleration, and the acceleration / deceleration set in advance is set based on the comparison result. In the above, the estimated vehicle body acceleration is sequentially updated, and when it is determined that the vehicle is in an acceleration / deceleration state, the current estimated vehicle body speed is sequentially updated with the vehicle body acceleration / deceleration to obtain an estimated vehicle body speed. Characterized in that it comprises a.

[0009]

In the estimated vehicle body speed computing device according to the present invention, the acceleration / deceleration determining means determines whether or not the vehicle is in the acceleration / deceleration state based on the acceleration / deceleration signal or the predetermined control signal. If it is determined that the vehicle is not in the acceleration / deceleration state, the estimated vehicle body speed calculation means compares the wheel speed with the estimated vehicle body speed, and based on the result, the estimated vehicle body speed is sequentially updated at a preset acceleration / deceleration. Therefore, since the detected vehicle body acceleration / deceleration is not used, the influence of noise is small. When the acceleration / deceleration determining means determines that the vehicle is in the acceleration / deceleration state, the estimated vehicle body speed computing means sequentially updates the current estimated vehicle body speed by the vehicle body acceleration / deceleration to obtain the estimated vehicle body speed. Therefore, the estimated vehicle body speed can be accurately obtained without being affected by the difference between the wheel speed generated in the acceleration / deceleration state and the actual vehicle body speed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An estimated vehicle speed calculating device according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a motorcycle, and the motorcycle 10 includes a main body portion 12, a front wheel portion 14 and a rear wheel portion 16. The front wheel portion 14 and the rear wheel portion 16 are provided with a driven wheel rotation speed sensor 18 and a drive wheel rotation speed sensor 20 each of which includes a rotary encoder and the like.
Two are provided. The sensors 18, 20, 22 are
The estimated vehicle body speed calculation device 30 shown in FIG. 1 is configured by being connected to the control unit 24.

The control unit 24 controls the front wheel portion 14 (driven wheel) and the rear wheel portion 16 (drive wheel) based on the output signals of the driven wheel rotation speed sensor 18 and the drive wheel rotation speed sensor 20.
Wheel speed calculation circuit 3 for calculating respective wheel rotation speeds
2a, 32b, an analog filter 34 for removing noise from the output signal of the vehicle body acceleration / deceleration detection sensor 22, an A / D converter 36 for converting the output signal from which the noise is removed into a digital signal, the digital signal or An acceleration / deceleration determination circuit 37 that determines the acceleration / deceleration state of the motorcycle 10 based on another control signal S, and wheel speed calculation circuits 32a, 3
Wheel speed signal from 2b, analog filter 34, A /
A vehicle acceleration signal from the vehicle body acceleration / deceleration detection sensor 22 supplied via the D converter 36 and an acceleration / deceleration determination circuit 37.
And an estimated vehicle body speed calculation circuit 38 for calculating the estimated vehicle body speed V _ref based on the acceleration / deceleration determination signal.

The estimated vehicle body speed computing device 30 thus constructed computes the estimated vehicle body speed V _ref as follows.

In the present embodiment, the wheel velocities of the driven wheel and the drive wheel are respectively obtained, and the respective estimated vehicle body velocities are obtained therefrom. Here, first, the driven wheel (the front wheel portion 1
How to obtain the estimated vehicle body speed from 4) will be described with reference to the flowchart of FIG. 3 and FIGS. The estimated vehicle body speed calculation circuit 38 obtains the estimated vehicle body speed _{Vref (n)} as follows at every predetermined calculation cycle t. here,
(N) indicates a value in the n-th calculation.

First, while the motorcycle 10 is running,
The driven wheel rotation speed sensor 18 arranged in the front wheel portion 14 is
The rotation of the driven wheels is detected as a pulse signal and output to the wheel speed calculation circuit 32a. The wheel speed calculation circuit 32a
Calculates the wheel rotation speed V _{W (n)} based on the pulse signal and outputs it to the estimated vehicle speed calculation circuit 38 (step S1).

On the other hand, the vehicle body acceleration / deceleration detection sensor 22 arranged in the main body 12 examines the vehicle body acceleration / deceleration Gx, and through the analog filter 34 and the A / D converter 36, the acceleration / deceleration determination circuit 37 and the estimated vehicle body. It is output to the speed calculation circuit 38 (step S2).

Therefore, the acceleration / deceleration determination circuit 37 determines that the vehicle body acceleration / deceleration Gx is a predetermined value α (α> 0) or more (| Gx |>
It is determined whether or not α) (step S3). If the vehicle body acceleration / deceleration Gx is less than or equal to a predetermined value α (| Gx | <α), there is no acceleration / deceleration, or vice versa (| Gx |>
In α), it is determined that acceleration / deceleration is in progress.

When it is determined that there is no acceleration / deceleration,
As shown, normally, the wheel rotation speed V _{W (n)}And actual vehicle speed
Degree V_iAnd the vehicle body acceleration / deceleration detection section
For the vehicle body acceleration / deceleration Gx obtained from the sensor 22,
It is considered that noise due to vibration of the vehicle 10 is mixed in
This is because that. Therefore, the acceleration / deceleration determination circuit 37 performs acceleration / deceleration.
When the acceleration / deceleration determination signal indicating that there is no
The degree calculation circuit 38 is preset as described below.
Estimated vehicle speed V from acceleration / deceleration_{ref (n)}Ask for.

That is, when it is determined in step S3 that there is no acceleration / deceleration, the wheel rotation speed V _{W (n)} input this time is input.
Is larger than the estimated vehicle body speed V _{ref (n-1)} obtained in the previous calculation (step S4). When it is determined that the wheel rotation speed V _{W (n)} is higher than the estimated vehicle body speed V _{ref (n-1)} , the estimated vehicle body speed V _{ref (n)} is obtained as follows (step S5).

V _{ref (n)} = V _{ref (n-1)} + G ₁ × t Here, G ₁ (> 0) is a preset acceleration, and t is a calculation cycle.

Further, in step S4, the wheel rotation speed V _{W (n)}
There when it is determined to be smaller than the estimated vehicle speed V _{ref (n-1)} further is larger than the estimated vehicle speed V _{ref (n-1)} is the wheel speed V _{W (n)} It is determined whether or not (step S6). The estimated vehicle speed V _{ref ( n-1)} is the wheel rotation speed V _{W (n)}
If it is larger than the above, the estimated vehicle speed V _{re is calculated} as follows.
_{f (n)} is obtained (step S7).

V _{ref (n)} = V _{ref (n-1)} -G ₂ × t where G ₂ (> 0) is a preset deceleration and t is a calculation cycle.

Further, in step S6, the estimated vehicle speed V
If _{the ref (n-1)} is determined not to be larger than the wheel speed V _{W (n),} the estimated vehicle speed V _{ref (n)} is determined as follows (step S8).

V _{ref (n)} = V _{ref (n-1) As described} above in steps S4 to S8, the wheel rotation speed V _{W (n)} is compared with the estimated vehicle body speed V _{ref (n-1).} Then, based on the result, the estimated vehicle body speed V _{ref (n)} is calculated to calculate the estimated vehicle body speed V _ref as shown in FIGS. 4 and 5.
_{ref (n)} is required with high accuracy.

By the way, in the motorcycle 10, for example, slippage occurs between the wheels and the road surface during deceleration, so that the wheel rotation speed V _W and the actual vehicle body speed V are increased as shown in FIG.
The difference with _i becomes large. Therefore, if the estimated vehicle body speed V _{ref (n)} is calculated based on the wheel rotation speed V _{W (n)} as shown in steps S4 to S8, the estimated vehicle body speed V _i close to the actual vehicle body speed V _i can be obtained with high accuracy. Can't ask for _ref .

Therefore, when the acceleration / deceleration determination circuit 37 determines that the vehicle body acceleration / deceleration Gx is equal to or greater than the predetermined value α, or the acceleration / deceleration determination circuit 37 receives the control signal S based on the driver's brake operation or accelerator operation. If it is supplied, it is assumed that the vehicle body is being accelerated or decelerated, and the method of obtaining the estimated vehicle body speed V _{ref (n)} is switched as follows (step S9).

V _{ref (n)} = V _{ref (n-1)} + ∫Gxdt where t is a calculation cycle. As described above, by using the value of the vehicle body acceleration / deceleration Gx, the highly accurate estimated vehicle body speed V _{ref (n)} can be obtained.

After obtaining the estimated vehicle body speed V _{ref (n)} in steps S5, S7, S8 and S9, n is incremented and
The calculation for _{obtaining the} estimated vehicle body speed V _{ref (n)} is repeated again.

From the rotational speed of the drive wheel (rear wheel portion 16), the estimated vehicle body speed V is obtained similarly to the driven wheel (front wheel portion 14).
_Ref can be obtained with high accuracy.

As described above, in the estimated vehicle body speed calculation device 30 according to the present embodiment, when it is determined that the motorcycle 10 is not accelerating or decelerating during traveling, the acceleration / deceleration preset based on the wheel rotation speed V _W is set. Since the estimated vehicle body speed _Vref is obtained using the velocities G ₁ and G ₂ , it is possible to obtain the highly accurate estimated vehicle body speed _Vref without the influence of noise output from the vehicle body acceleration / deceleration detection sensor 22. Further, at the time of acceleration and deceleration, by using the detected acceleration of the vehicle Gx of the vehicle body acceleration sensor 22, it does not suffer the effect of the difference between the actual vehicle speed V _i and the wheel speed V _w by the slip Precision The estimated vehicle body speed V _{ref (n)} can be obtained at.

[0031]

According to the estimated vehicle body speed calculation device of the present invention, the following effects can be obtained.

That is, the acceleration / deceleration determining means determines whether or not the vehicle is in the acceleration / deceleration state based on the acceleration / deceleration signal or a predetermined control signal. And the estimated vehicle body speed are compared with each other, and the estimated vehicle body speed is sequentially updated at a preset acceleration / deceleration based on the result. Therefore, since the detected vehicle body acceleration is not used, the influence of noise is small. Further, when the acceleration / deceleration determining means determines that the vehicle is in the acceleration / deceleration state, the estimated vehicle body speed computing means sequentially updates the current estimated vehicle body speed with the vehicle body acceleration / deceleration to obtain the estimated vehicle body speed. Therefore, the estimated vehicle body speed can be accurately obtained without being affected by the difference between the wheel speed and the actual vehicle body speed due to the slip generated during acceleration / deceleration.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an estimated vehicle body speed calculation device according to the present invention.

FIG. 2 is an explanatory diagram of a motorcycle equipped with an estimated vehicle body speed calculation device according to the present invention.

FIG. 3 is a flowchart showing a calculation method of the estimated vehicle body speed calculation device according to the present invention.

FIG. 4 is a diagram showing a calculation result of an estimated vehicle body speed calculation device according to the present invention.

FIG. 5 is an explanatory diagram of a calculation method of the estimated vehicle body speed calculation device according to the present invention.

[Explanation of symbols]

 10 ... Motorcycle 18 ... Driven wheel rotation speed sensor 20 ... Drive wheel rotation speed sensor 22 ... Vehicle body acceleration / deceleration detection sensor 30 ... Estimated vehicle speed calculation device 37 ... Acceleration / deceleration determination circuit 38 ... Estimated vehicle speed calculation circuit

Claims (1)

[Claims] 1. An estimated vehicle body speed calculation device for calculating an estimated vehicle body speed from wheel speeds and vehicle body acceleration / deceleration, comprising: a vehicle wheel speed detection means for detecting a wheel speed; and a vehicle body acceleration / deceleration detection means for detecting a vehicle body acceleration / deceleration. An acceleration / deceleration determination means for determining whether the vehicle body is in an acceleration / deceleration state based on an acceleration / deceleration signal or a predetermined control signal from the vehicle body acceleration / deceleration detection means; If it is determined that there is not, the estimated vehicle body acceleration is sequentially updated at a preset acceleration / deceleration by comparing the wheel speed with the current estimated vehicle body acceleration, and it is determined that the vehicle is in an acceleration / deceleration state. In this case, an estimated vehicle body speed calculation device, comprising: an estimated vehicle body speed calculation means for sequentially updating the current estimated vehicle body speed with the vehicle body acceleration / deceleration to obtain the estimated vehicle body speed.