JP3210418B2 - Estimated vehicle speed calculation 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 speed calculating device for calculating a vehicle speed of a vehicle from a wheel speed and a vehicle acceleration / deceleration.

[0002]

2. Description of the Related Art In automobiles and motorcycles, a so-called brake control device for controlling the wheel speed of a vehicle during braking by comparing it with the vehicle speed is used. In this brake control device, the slip rate is obtained from the wheel speed and the vehicle speed, and when the slip ratio becomes equal to or higher than the target slip ratio, the wheel speed is controlled by reducing the brake oil pressure to reduce the slip ratio. To obtain the optimum braking force.

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

Incidentally, the wheel speed can be directly detected by a sensor from the rotation speed of the wheel, but it is difficult to directly detect the vehicle speed by the sensor. This is practically impossible with vehicles whose size is severely limited. Therefore, a method of estimating the vehicle speed is usually adopted from the wheel speed or the vehicle acceleration / deceleration.

In this case, a method of selecting the wheel speed of the fastest rotating wheel among a plurality of wheels to obtain an estimated vehicle speed (Japanese Patent Laid-Open No. 63-78867) (hereinafter, Hi-sel)
ect method), a method of integrating and calculating the vehicle acceleration / deceleration detected by the vehicle acceleration / deceleration detector (Japanese Patent Application Laid-Open No. 63-1988).
No. -24166), or a method of comparing the wheel speed with the current estimated vehicle speed and updating and obtaining the estimated vehicle speed at a constant acceleration / deceleration based on the comparison result.

[0006]

However, in a situation where the wheels slip on the road surface, the estimated vehicle speed may be set to be higher than the actual vehicle speed. In this case, when a slip state occurs at the time of starting or the like, in the Hi-select system, there is a possibility that control in the brake control device or the driving force control device may be inappropriate. Further, in the method of calculating the estimated vehicle speed by integrating the detected vehicle acceleration / deceleration, noise may be mixed in the vehicle body acceleration / deceleration due to vibration of the vehicle based on road surface conditions or the like. Accordingly, when integrating and updating the vehicle body acceleration / deceleration, noise is also integrated, and the estimated vehicle body speed may depart from the actual vehicle body speed. Further, in the method of determining the vehicle body speed using a predetermined acceleration / deceleration, the predetermined acceleration / deceleration must be switched between a low friction (low μ) road surface and a high friction (high μ) road surface. There is complexity.

SUMMARY OF THE INVENTION The present invention has been made to solve this kind of problem, and has an object to calculate an estimated vehicle speed which can easily and accurately estimate a vehicle speed required for brake control, driving force control and the like. It is intended to provide a device.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an estimated vehicle speed calculating device for calculating an estimated vehicle speed from a wheel speed and a vehicle acceleration / deceleration. Speed detecting means, vehicle body acceleration / deceleration detecting means for detecting vehicle body acceleration / deceleration, and determining whether or not 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 detecting means. a deceleration determining means for, when it is determined not in the acceleration or deceleration state by the acceleration and deceleration determining means, comparing the estimated <br/> vehicle body speed of the wheel speed and the current, based on the comparison result , and sequentially updates the estimated vehicle body speed at a preset deceleration, if it is determined that the acceleration or deceleration state, the estimated vehicle for obtaining the estimated vehicle speed by successively updating the present estimated vehicle body speed in the acceleration of the vehicle Speed calculator Characterized in that it comprises a and.

[0009]

In the estimated vehicle speed calculating 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 a predetermined control signal. When it is determined that the vehicle is not in the acceleration / deceleration state, the estimated vehicle speed is calculated by the estimated vehicle speed calculation means, and the estimated vehicle speed is sequentially updated at a preset acceleration / deceleration based on the result. Therefore, since the detected vehicle 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 speed is sequentially updated by the estimated vehicle speed calculating means based on the vehicle acceleration / deceleration to obtain the estimated vehicle speed. Therefore, the estimated vehicle speed is accurately obtained without being affected by the difference between the wheel speed and the actual vehicle speed generated during the acceleration / deceleration state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an apparatus for calculating an estimated vehicle speed according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 denotes a motorcycle. The motorcycle 10 includes a main body 12, a front wheel 14, and a rear wheel 16. The front wheel portion 14 and the rear wheel portion 16 are respectively provided with a driven wheel rotational speed sensor 18 and a drive wheel rotational speed sensor 20 each comprising a rotary encoder or the like.
2 are provided. The sensors 18, 20, 22
These are connected to the control unit 24, and these constitute an estimated vehicle speed calculating device 30 shown in FIG.

The control unit 24 determines the front wheel portion 14 (driven wheel) and the rear wheel portion 16 (driving wheel) from 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 each wheel rotation speed
2a, 32b, an analog filter 34 for removing noise from the output signal of the vehicle acceleration / deceleration detection sensor 22, an A / D converter 36 for converting the noise-free output signal into a digital signal, An acceleration / deceleration determination circuit 37 for determining the acceleration / deceleration state of the motorcycle 10 based on another control signal S;
2b, an analog filter 34, A /
A vehicle acceleration signal from the vehicle acceleration / deceleration detection sensor 22 supplied via a D converter 36 and an acceleration / deceleration determination circuit 37
And an estimated vehicle speed calculation circuit 38 for calculating the estimated vehicle speed _Vref based on the acceleration / deceleration determination signal from the CPU.

The estimated vehicle speed calculating device 30 configured as described above calculates the estimated vehicle speed _Vref as follows.

In this embodiment, the wheel speeds of the driven wheels and the drive wheels are obtained, and the estimated vehicle speeds are obtained therefrom. Here, first, the driven wheel (the front wheel 1
The method of obtaining the estimated vehicle speed from 4) will be described with reference to the flowchart of FIG. 3 and FIGS. The estimated vehicle speed calculating circuit 38 obtains the estimated vehicle speed _{Vref (n)} as follows in each predetermined calculation cycle t. here,
(N) indicates a value in the n-th calculation.

First, while the motorcycle 10 is traveling,
The driven wheel rotation speed sensor 18 disposed on the front wheel portion 14 is
The rotation of the driven wheel 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 acceleration / deceleration detecting sensor 22 provided in the main body 12 examines the vehicle acceleration / deceleration Gx, and receives an acceleration / deceleration discrimination circuit 37 and an estimated vehicle speed via an analog filter 34 and an A / D converter 36. The output 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 equal to or greater than a predetermined value α (α> 0) (| Gx |>
α) is determined (step S3). When the vehicle body acceleration / deceleration Gx is equal to or less than a predetermined value α (| Gx | <α), no acceleration / deceleration is performed, and in the opposite case (| Gx |>).
In α), it is determined that acceleration / deceleration is being performed.

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

That is, if 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 higher than the estimated vehicle speed _{Vref (n-1)} obtained in the previous calculation (step S4). Here, when it is determined that the wheel rotation speed V _{W (n)} is higher than the estimated vehicle speed V _{ref (n-1)} , the estimated vehicle speed V _{ref (n)} is obtained as follows (step S1 _). 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.

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 this is the case (step S6). The estimated vehicle speed _{Vref ( n-1)} is _equal to the wheel rotation speed _{VW (n).}
If it is larger than the estimated vehicle speed V _{re,
f (n)} is obtained (step S7).

[0022] _{V ref (n) = V ref} (n-1) -G 2 × t _Here, G 2 (> 0) is deceleration set in advance, t is calculation period.

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 in steps S4 to S8, the wheel rotation speed V _{W (n)} is compared with the estimated vehicle speed V _{ref (n-1).} Then, based on the result, the estimated vehicle speed _{Vref (n)} is calculated, as shown in FIGS.
_{ref (n)} is required with high accuracy.

By the way, the motorcycle 10, for example, because the slip is generated between the wheel and the road surface at the time of deceleration, as shown in FIG. 4, the actual vehicle speed V and the wheel speed V _W
The difference from _i increases. Therefore, when the operation in step S4 to S8 at the indicated such wheel rotation speed V _{W (n)} to the based estimated vehicle velocity V _{ref (n),} high accuracy close to the actual vehicle speed V _i of the estimated vehicle speed V 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 when the acceleration / deceleration determination circuit 37 outputs a control signal S based on the driver's brake operation or accelerator operation. If supplied, it is determined that the vehicle is accelerating and decelerating, and the method of obtaining the estimated vehicle speed _{Vref (n)} is switched as follows (step S9).

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

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

The estimated vehicle speed V is obtained from the rotational speed of the drive wheel (rear wheel portion 16) as in the case of the driven wheel (front wheel portion 14).
_ref can be obtained with high accuracy.

[0030] Thus, the estimated vehicle speed calculating unit 30 according to the present embodiment, when the motorcycle 10 is determined to acceleration and deceleration without during traveling, acceleration that is set in advance based on the wheel speed V _W to determine the estimated vehicle velocity V _ref using the velocity G _1, G _2, there is no influence of noise outputted from the acceleration of the vehicle sensor 22 is obtained a highly accurate estimated vehicle speed V _ref. 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 speed _{Vref (n)} can be obtained at the same time.

[0031]

According to the estimated vehicle speed calculating device according to the present invention, the following effects can be obtained.

That is, the acceleration / deceleration determining means determines whether or not the vehicle is in an acceleration / deceleration state based on an acceleration / deceleration signal or a predetermined control signal. Is compared with the estimated vehicle speed, and based on the result, the estimated vehicle speed is sequentially updated at a preset acceleration / deceleration. Therefore, since the detected vehicle acceleration 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 speed is sequentially updated by the estimated vehicle speed calculating means with the vehicle acceleration / deceleration to obtain the estimated vehicle speed. Therefore, the estimated vehicle speed is accurately obtained without being affected by the difference between the wheel speed and the actual vehicle speed due to the slip generated during acceleration / deceleration.

[Brief description of the drawings]

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

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

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

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

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

[Explanation of symbols]

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

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-86666 (JP, A) JP-A-1-249560 (JP, A) JP-A-4-50066 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B60T 8/00-8/96

Claims (1)

(57) [Claims] 1. An estimated vehicle speed calculating device for calculating an estimated vehicle speed from a wheel speed and a vehicle acceleration / deceleration, comprising: wheel speed detecting means for detecting wheel speed; vehicle speed detecting / acceleration detecting means for detecting vehicle speed. Based on an acceleration / deceleration signal or a predetermined control signal from the vehicle acceleration / deceleration detection means, acceleration / deceleration determination means for determining whether or not the vehicle body is in an acceleration / deceleration state; If it is determined that no, the wheel speed and comparing the current of the estimated vehicle body speed based on the comparison result, and sequentially updates the estimated vehicle body speed at a preset acceleration, deceleration An estimated vehicle speed calculating means for successively updating the current estimated vehicle speed with the vehicle acceleration / deceleration to determine the estimated vehicle speed when the state is determined.