JP3488782B2 - Vehicle wheel speed calculation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts the output signal of a single wheel speed sensor fixed on the vehicle body side into a rectangular wave corresponding to a pulsar gear fixed to a wheel, and a rising edge of the rectangular wave. The present invention relates to a vehicle wheel speed calculating device for calculating a wheel speed based on at least one of a falling edge and a falling edge.

[0002]

2. Description of the Related Art Conventionally, it is known that one of a rising edge and a rising edge is used to calculate the wheel speed, and that both a rising edge and a rising edge are used as disclosed in Japanese Patent Laid-Open No. 5-133967. Has been.

[0003]

However, in the case where the wheel speed is calculated by using one of the rising edge and the rising edge, there is not enough rectangular wave input at low speed running, and the calculation accuracy is lowered. In addition, if the wheel speed is calculated using both the rising edge and the rising edge, the calculation accuracy during low-speed running can be improved, but the number of rectangular waves input increases during high-speed running, resulting in a large number of edges. As a result, the load on the arithmetic unit increases and the performance required for the arithmetic unit becomes severe.

The present invention has been made in view of the above circumstances, and provides a wheel speed calculation device for a vehicle, which improves the calculation accuracy during low-speed traveling and reduces the load on the calculation device during high-speed traveling. The purpose is to

[0005]

In order to achieve the above object, the present invention according to claim 1 provides an output of a single wheel speed sensor fixed to the vehicle body side corresponding to a pulsar gear fixed to a wheel. In a wheel speed calculating device for a vehicle, which converts a signal into a rectangular wave, and calculates a wheel speed based on at least one of a rising edge and a falling edge of the rectangular wave,
A first wheel speed index based on a rising edge and a second wheel speed index based on a falling edge can be calculated, and when one of the first and second wheel speed indexes exceeds a preset reference value, The wheel speed is calculated based on the one wheel speed index, and if the one wheel speed index is equal to or less than a reference value, the rising error is calculated.
It is characterized in that the wheel speed is calculated based on the wheel speed index based on the latest edge of the edge and the falling edge.

The invention according to claim 2 is the above-mentioned claim 1.
In addition to the configuration of the invention described above, the two-wheel speed index is a count value of each edge within a predetermined time.

Further, the invention according to claim 3 is characterized in that, in addition to the configuration of the invention according to claim 1, the both wheel speed indexes are obtained based on the intervals between the edges.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings.

1 to 3 show an embodiment of the present invention, FIG. 1 is a block diagram showing the configuration of a wheel speed calculating device, FIG. 2 is a flowchart showing a wheel speed calculating processing procedure, and FIG. It is a timing chart.

First, in FIG. 1, for example, in order to obtain a wheel speed of a front wheel or a rear wheel in a motorcycle, a pulsar gear 1 having a plurality of teeth 2, 2, ... The wheel speed sensor 3 is fixed to the vehicle body side, for example, facing the side surface of the pulsar gear 1. Thus, the teeth 2, 2, ... Of the pulsar gear 1, which rotates with the front wheels or the rear wheels, are wheel speed sensors 3.
The signal output from the wheel speed sensor 3 every time it passes through the portion corresponding to the above is input to the waveform shaping circuit 5 via the amplifier circuit 4, and in the waveform shaping circuit 5, a rectangle whose duty is, for example, about 50%. Waves are obtained.

The rectangular wave output from the waveform shaping circuit 5 is input to the edge selector 6, and the rising edge and the falling edge of the rectangular wave are selected by the edge selector 6. The rising edge selected by the edge selector 6 is the edge counter 7up,
The falling edges input to the timer memories 8up and 9up and selected by the edge selector 6 are input to the edge counter 7dn and the timer memories 8dn and 9dn, respectively, and the respective timer memories 8up, 9up and 8d.
A pulse signal at a predetermined interval is input from the timer 10 to n and 9dn.

The edge counter 7up counts the number of rising edges within a constant calculation time T to obtain a first count value Cup as a first wheel speed index, and the timer memory 8up stores this time. The time Tup from the input of the last rising edge in the calculation time T to the end of the calculation time T is repeatedly stored, and the timer memory 9up inputs the last rising edge in the calculation time T of the previous time. The time Tupx from the input of the last rising edge within the calculation time T of this time is repeatedly stored.

The edge counter 7dn counts the number of falling edges within a certain calculation time T to obtain a second count value Cdn as a second wheel speed index.
The timer memory 8dn repeatedly stores the time Tdn from the input of the last falling edge within the current calculation time T to the end of the calculation time T, and the timer memory 9dn stores within the last calculation time T. The time Tdnx from the input of the last falling edge to the input of the last falling edge within the current calculation time T is repeatedly stored.

The outputs of both edge counters 7up and 7dn, that is, the first and second count values Cup and Cdn, and the times Tupx and Tdnx obtained by the timer memories 9up and 9dn are input to the arithmetic processing unit 11. The outputs of the comparators 12, 13, 14, 15 are also input to the arithmetic processing unit 11. Thus, the output of the edge counter 7up is input to the non-inverting input terminal of the comparator 12, and the signal corresponding to the predetermined reference value C1 is input from the reference terminal 16 to the inverting input terminal of the comparator 12. To be done. The reference value C1 is, for example, an edge count value corresponding to twice, and Cup> C1
At this time, the high level signal output from the comparator 12 is input to the arithmetic processing unit 11. Moreover, the output of the comparator 12 is also given to the edge counter 7dn, and the edge counter 7dn receives the second count value when a low-level signal is input from the comparator 12, that is, when Cup≤C1. In order to obtain Cdn, the number of falling edges within a fixed time T is counted.

In the comparator 13, the output signal of the edge counter 7up is input to its non-inverting input terminal, and the output signal of the edge counter 7dn is input to its inverting input terminal. Therefore, when Cup> Cdn, the comparator 13 outputs a high level signal. In the comparator 14, the output signal of the edge counter 7dn is input to its non-inverting input terminal, and the output signal of the edge counter 7up is input to its inverting input terminal. Therefore Cdn> Cup
Then, the comparator 14 outputs a high level signal.

The output signal of the timer memory 8dn is input to the non-inverting input terminal of the comparator 15, and the output signal of the timer memory 8up is input to the inverting input terminal of the comparator 15. Therefore, the comparator 15 outputs a high level signal when Tup <Tdn.

In the arithmetic processing section 11, the wheel speed is set in accordance with the processing procedure shown in FIG. 2 based on the signals respectively inputted from the both edge counters 7up and 7dn, the timer memories 9up and 9dn, and the comparators 12, 13, 14 and 15. Is calculated.

In step S1 of FIG. 2, it is determined whether Cup> C1. That is, it is determined whether or not the first count value Cup exceeds the reference value C1, and when Cup> C1, the flag F is set to "0" in step S2 and the process proceeds to step S3.

In step S3, the wheel speed is calculated using the first count value Cup. That is, after calculating the average time interval tupa of each rising edge as tupa = Tupx / Cup, the wheel speed V is calculated as V = K / tupa. Here, the symbol K indicates the pulsar gear 1
Is a constant determined according to.

When it is determined in step S1 that Cup≤C1, it is determined in step S4 whether or not the flag F is "1". If F = 0, in step S5 F After setting = 1, the process proceeds to step S3, and when F = 1, the process proceeds to step S6. That is, in the first processing cycle with Cup ≦ C1,
In step S3, the wheel speed is calculated using the first count value Cup, and after the second time, the process proceeds to step S6.

In step S6, it is determined whether or not Cup <Cdn. If Cup <Cdn, step S7.
Then, the calculation of the wheel speed using the second count value Cdn is executed. That is, the average time interval tdna of the falling edges
Is calculated as tdna = Tdnx / Cdn, and then the wheel speed V is calculated as V = K / tdna.

If it is determined in step S6 that Cup ≧ Cdn, the process proceeds to step S8 to determine whether or not Cup> Cdn. If Cup> Cdn, the process proceeds to step S3, and Cup = Cdn. If it is, it is determined in step S9 whether Tup <Tdn and Tup
<If Tdn, go to step S3, and again Tup ≧ T
If it is dn, the process proceeds to step S7.

Summarizing such a processing procedure, when the first count value Cup based on the rising edge exceeds the reference value C1, the wheel speed V is calculated based on the first count value Cup,
When the first count value Cup is less than or equal to the reference value C1 (Cup ≦ C1), wheel speed calculation using the second count value Cdn when Cup <Cdn, and first count value Cup when Cup> Cdn , Wheel speed calculation using Cp = Cdn, time T
The wheel speed V is calculated using the count values Cup and Cdn having smaller up and Tdn. That is, when Cup ≦ C1, the wheel speed V is calculated based on the latest edge value of the two count values Cup and Cdn.

Next, the operation of this embodiment will be described with reference to FIG. 3. When the first count value Cup (the number of rising edges) exceeds 2 as shown in A and B of FIG.
That is, when the first count value Cup is three times or more, the wheel speed V is calculated using the first count value Cup. As shown by C to G in FIG. 3, when the first count value Cup is two times or less, the wheel speed V is calculated based on the latest edge value of the first and second count values Cup and Cdn. To do. That is, as in C and G of FIG. 3, the wheel speed V is calculated based on the first count value Cup when Cup> Cdn, and the second count value Cdn is set when Cup <Cdn as shown in E of FIG. Based on the calculation of the wheel speed V, the first count value Cup is used when Cup = Cdn and the rising edge is the latest as shown in D of FIG. 3, and as shown in F of FIG. = Cdn and the latest falling edge, the wheel speed V is calculated using the second count value Cdn.

Therefore, when the traveling speed is high, one of the rising edge and the falling edge, which is the rising edge in this embodiment, is used as the first count value C.
By calculating the wheel speed V using up, it is possible to reduce the load on the arithmetic device and prevent the arithmetic device from being required to have strict performance.

When the traveling speed is low, the wheel speed V is calculated using the latest edge value of the two count values Cup and Cdn, so that only one of the rising edge and the falling edge is used. It is possible to improve the calculation accuracy by increasing the number of edge appearances within a constant calculation time T as compared with the case where the speed is calculated.

In the above embodiment, the edge appearance count value is used as the wheel speed index. However, the wheel speed index may be obtained based on the edge appearance interval. The same effect as the example can be obtained.

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 design changes can be made without departing from the present invention described in the claims. It is possible to do.

For example, the present invention is widely applicable not only to motorcycles but also to vehicles such as four-wheeled vehicles.

[0030]

As described above, according to the first to third aspects of the present invention, when the vehicle is traveling at a high speed, the wheel speed is calculated using either one of the rising edge and the falling edge. It is possible to reduce the load on the vehicle and to improve the calculation accuracy by calculating the wheel speed using the latest edge among the rising edge and the falling edge when the vehicle is traveling at a low speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wheel speed calculation device.

FIG. 2 is a flowchart showing a wheel speed calculation processing procedure.

FIG. 3 is a timing chart.

[Explanation of symbols]

1 ... Pulsar Gear 3 ... Wheel speed sensor C1 ... Standard value Cdn: second count value as second wheel speed index Cup ... First count value as first wheel speed index

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Isao Matsuno 840 Kokubu, Ueda City, Nagano Prefecture Nisshin Kogyo Co., Ltd. (56) Reference JP-A-4-344466 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01P 3/489

Claims (3)

(57) [Claims] 1. An output signal of a single wheel speed sensor (3) fixed to a vehicle body corresponding to a pulsar gear (1) fixed to a wheel is converted into a rectangular wave, and a rising edge of the rectangular wave is converted. In a vehicle wheel speed calculating device for calculating a wheel speed based on at least one of a rising edge and a falling edge, a first wheel speed index (Cup) based on a rising edge.
And the second wheel speed index (C
dn) can be calculated respectively, and when one (Cup) of the first and second wheel speed indexes (Cup, Cdn) exceeds a preset reference value (C1), the one wheel speed index (Dup) is calculated. Cup), the wheel speed is calculated, and if the one wheel speed index (Cup) is equal to or less than the reference value (C1), the wheel speed index based on the latest edge of the rising edge and the falling edge is used. A vehicle wheel speed calculating device for calculating a wheel speed according to claim 1. 2. The wheel speed calculation device for a vehicle according to claim 1, wherein the both wheel speed indexes (Cup, Cdn) are count values of each edge within a predetermined time. 3. The vehicle wheel speed computing device according to claim 1, wherein the both wheel speed indexes are obtained based on the intervals between the edges.