JPH06199220A - Anti-lock electronic control method - Google Patents

Abstract

PURPOSE:To enhance the control ability and reliability by using in combination. a GP signal in the anti-lock control circuit of a brake which plies brakes to car wheels. CONSTITUTION:An anti-lock control circuit 10 has an ABS calculation control circuit 12, and thereto signals from ordinary acceleration sensors S1-S4 are fed, and also speed signal from a GPS receiver 2 is fed, and anti-lock control is conducted under certain conditions on the basis of the speed signal due to GPS signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock control method for braking wheels while referring to a vehicle speed signal and acceleration / deceleration signal obtained by using signals from a satellite for a global positioning system.

[0002]

2. Description of the Related Art Global Positioning System (Global P
The Positioning System (hereinafter abbreviated as GPS) can receive signals from a plurality of satellites (usually 3 or more) to know the current position of the moving body,
It is an absolute position detection system that can obtain the latitude, longitude, and altitude of the reception point anywhere in the world.

Such a GPS system is used for ships, aircrafts,
It has been attracting attention because it is used in navigation devices for moving bodies such as automobiles.

The GPS receiver used in the navigation device for a mobile body has generally been improved in various ways so that the current position information can be accurately received, and at present, extremely high accuracy information about the position information can be obtained.

The highly accurate position information obtained by such a navigation device can be applied not only to the navigation device but also to various other systems, one example of which is Japanese Patent Laid-Open No. 2-1.
No. 06415 discloses a tire abnormality warning device.

In this alarm device, all the position information received by the GPS receiver is temporarily stored in the memory, and the moving speed moving between the previously stored position information and the currently received position information is increased. The speed difference is calculated by the calculation circuit, and the speed detected by the speed sensor separately provided in the vehicle is calculated by the speed difference detector.If the speed difference exceeds a certain range, an alarm signal is sent to the alarm device as a tire abnormality. It is configured to feed and detect tire abnormalities.

[0007]

However, even if the position information obtained by the conventional navigation device has high accuracy, depending on the field to which the position information is applied, whether or not the position information can be immediately applied requires various studies in each field. .

[0008] For example, an anti-lock system for braking a vehicle wheel (abbreviated as ABS hereinafter) relates to a serious function in which braking of a wheel is fatal to human life.
Conventionally, it has never been performed to send an alarm to the electronic control circuit of the ABS based on the above position information or to perform control based on the information.

In the conventional ABS, the speed and acceleration of each wheel are obtained based on the information of the rotation speed sensor attached to the wheel part and the differential gear part, and the speed and acceleration of the vehicle are estimated. The lock state of each wheel is detected from the difference between the speed of the vehicle and the speed of each wheel. Then, depending on the locked state, the brake of each wheel is loosened or returned to perform control.

Even when the wheel speed is not stable as in the ABS operation, the vehicle speed can be estimated with a certain degree of accuracy by estimating the vehicle speed based on the wheel speed with a small lock amount at each occasion.

However, when the wheels simultaneously go to the locked state, the accuracy of the estimated vehicle speed and acceleration is significantly reduced. Therefore, there is also a system in which an acceleration sensor is additionally mounted mainly on a four-wheel drive vehicle in which simultaneous four-wheel lock is likely to occur.

However, the acceleration sensor has a problem that the error is large because the signal changes not only on the acceleration of the vehicle but also on a slope or the like.

In addition to the above, in a system having an acceleration sensor, it is difficult to detect a failure of the acceleration sensor because there is no reference sensor for evaluating the output value of the acceleration sensor, and similarly, wheel lock or spin occurs. Assuming that, there is no speed sensor as a reference for accurately detecting a failure in speed information as well, and there is also a method of detecting the absolute speed of the vehicle by installing a ground speed sensor such as a spatial filter, but it is costly. Therefore, there are various problems that it is difficult.

The present invention relates to the above-mentioned conventional speed sensor,
Paying attention to the current state of the ABS control method using only the acceleration sensor, the signal of the global positioning system (GPS) is converted into the speed signal and the acceleration signal for the braking of the anti-lock control, and the signal for the anti-lock control is converted. An object of the present invention is to provide an anti-lock electronic control method capable of improving control capability and reliability in combination with a signal from a wheel speed sensor.

[0015]

As a means for solving the above problems, the present invention sends a speed information signal detected by a wheel speed sensor, and based on this speed information signal, a wheel speed, acceleration and estimation according to a predetermined calculation program. The vehicle speed, acceleration, etc. are obtained, and when the wheels are locked or tending to lock as a result, the control is released, and when the locking or locking tendency disappears, braking is resumed and the braking of the wheels is controlled so that this is repeated as necessary In the anti-lock electronic control method, one or both of the speed and acceleration of the vehicle is calculated by calculation from the information on the position of the traveling vehicle detected by receiving the radio waves transmitted from a plurality of artificial satellites by the GPS receiver, and the constant value is obtained. Under the conditions, the braking of the wheels is controlled based on the vehicle speed and acceleration signals based on the received signals.

In this case, the receiving speed or acceleration signal can be obtained from a navigation device that detects and displays the position information of the vehicle.

For any of the above control methods, the vehicle speed value estimated from the rotational speed of the wheel is added to the GP value.
Correction calculation may be performed using the speed signal received by the S receiver, and control may be performed using the estimated vehicle speed.

Alternatively, the vehicle speed estimated based on the rotation speed of the wheel and the signal of the acceleration sensor mounted on the vehicle is corrected by using the speed calculated value from the GPS receiver, and the speed information is added to the speed information. The control may be performed using the estimated vehicle body speed based on the above.

Further, the estimated acceleration of the vehicle estimated from the rotation speed of the wheels may be corrected by using the acceleration value from the GPS receiver, and the estimated acceleration may be used for control. The acceleration estimated based on the rotation speed of the wheel and the signal of the acceleration sensor is used as the GP.
The acceleration value from the S receiver may be used for correction, and the estimated acceleration may be used for control.

[0020]

According to the control method of the present invention, which is the above method, either or both of the speed and the acceleration of the vehicle can be determined from the position information of the traveling vehicle detected by receiving the radio waves transmitted from a plurality of artificial satellites. The calculated braking force is used to electronically control the vehicle braking force.

It is desirable from the viewpoint of cost to obtain the information on the position of the traveling vehicle or the information on the speed and the acceleration calculated from the information from the navigation system which is also mounted on the vehicle.

Not only the information on the vehicle speed and acceleration obtained from the information on the position of the traveling vehicle is used for direct control, but also the information from the wheel speed sensor and / or the acceleration sensor also mounted on the vehicle is used. It is desirable in terms of accuracy to use it for control after performing correction calculations. On the contrary, it is also possible to use the information of the wheel speed sensor or the acceleration sensor as the main information and correct this value with the information obtained by calculating from the position. Further, failure detection of a wheel speed sensor or an acceleration sensor also mounted on the vehicle may be performed based on the vehicle speed and acceleration information obtained from the position information of the traveling vehicle.

[0023]

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

FIG. 1 is a schematic block diagram including the ABS control circuit of the first embodiment and a circuit attached thereto. The ABS control circuit 10 is based on the premise that a known global positioning system (GPS system) is used.

1 is an antenna, 2 is a GPS receiver,
For example, it may be used for a so-called navigation system in which the current position of the automobile is shown on a map displayed on an image display, or may be provided with only the above-mentioned functional parts independently.

The signal received by the GPS receiver 2 is stored in the memory 3, and the signal of the current position received by the GPS receiver 2 and the signal representing the previous position stored in the memory 3 are subjected to speed calculation. When sent to the circuit 4, the speed of the vehicle is calculated.

The calculation of the speed is performed by calculating the difference between the current position (x _i , y _i , z _i ) of the vehicle and the position (x _{i -1} , y _i-1 , z _i-1 ) at the time of the previous sampling and the sampling time. Δ
From t, it is calculated by the following equation.

V _i = {(x _i −x _i−1 ) ² + (y _i −y
^{_{i-1) 2 + (z}} i -z i-1) 2} 1/2 / Δt On the other hand, apart from the velocity signal by the GPS receiver 2, A
In the BS control circuit 10, the wheel speed sensors S _{1 to} S are generally used.
_The wheel speed information is detected by ₄ and the wheel speed signal is obtained by the wheel speed detection circuit 11 from them.

The wheel speed signal is transmitted to the ABS arithmetic control circuit 1
2, the control circuit calculates the estimated vehicle body speed, estimated vehicle body acceleration, etc. based on the wheel speed signal and also obtains the slip ratio of the wheels to determine whether the wheels are locked or tend to be locked. .

If the result of the above judgment is that the lock or lock tendency is found, the ABS arithmetic control circuit 12 sends a control signal to the drive circuit 13 to drive each or some of the solenoids 14 to loosen the brake. , When the lock or lock tendency disappears, the brake is controlled again.

In the general ABS control method as described above, when traveling on a slippery road surface such as water or ice, etc., it is obtained from the speed signal based on the information from the wheel speed sensors S _{1 to} S _4. Values of the estimated wheel speed, etc., that are generated may differ greatly from the actual values, and the reliability of the estimated vehicle body speed value becomes extremely low.

Therefore, in such a case, a speed signal is sent from the wheel speed detecting circuit 11 to the speed difference calculating circuit 15, and
A speed signal by the GPS receiver 2 described above are sent to the speed difference calculating circuit 15, a constant value or more there is a difference between the speed V _i by the wheel speed sensors S ₁ each wheel speed SV ₁ Sv ₄ and GPS by to S ₄ Then, it is determined that the wheel is locked, and the ABS control arithmetic circuit 12 controls to loosen the brake of the wheel.

A flow chart of the above control method is shown in FIG. The contents of each step T _{1 to} T ₈ are as shown in the figure and need not be described.

FIG. 3 is a schematic block diagram including the ABS control circuit 10 of the second embodiment and a circuit portion provided around it. In this embodiment, the speed difference calculation circuit 1 of the first embodiment is used.
5 is omitted, and an acceleration calculation circuit 16 and an acceleration determination circuit 17 are provided instead instead. The other members having the same function are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, attention is paid to the fact that the signal from the GPS receiver 2 can also be used as an acceleration signal, so that it is used to determine the acceleration.

The signal obtained by the speed calculation circuit 4 is sent to the acceleration calculation circuit 16 and the acceleration is calculated according to the following equation.

A _i = (V _i −V _i−1 ) / Δt The obtained acceleration signal is sent to the acceleration judgment circuit 17,
It is determined whether the acceleration value a _i is greater than 0.4 G or less than 0.4 G, and an output signal according to the determination result is sent to the ABS arithmetic control circuit 12.

In the above control circuit, the above GP is performed as follows.
The S signal is used.

[0039] If four wheel speed SV ₁ Sv ₄ of the automobile is abruptly reduced, it is expected the following two things.

(1) The road surface has a high friction coefficient (μ) surface such as asphalt, and brake braking is good.

(2) The road surface is a low μ surface such as on ice, and four wheels are heading toward the lock at the same time.

If the phenomenon occurring is (1), the braking must be continued.

On the other hand, in the case of (2), the brake must be loosened to avoid the locked state.

It is difficult to make the above determination accurately from the signal of the wheel speed, and generally an acceleration sensor is separately provided and the determination is made based on the signal from this.

In this embodiment, instead of the judgment by the general acceleration sensor, the judgment is made on the basis of the acceleration signal obtained from the GPS signal.

Therefore, if the acceleration calculated from the GPS signal is as high as 0.4 G or more, it is determined to be (1) and the strong braking force is continued.

If it is as low as 0.4 G or less, it is judged as (2),
Release the braking force.

FIG. 4 is a schematic block diagram of the third embodiment. The ABS control circuit 10 of this embodiment differs from the ABS control circuit 10 of the first embodiment only in that a vehicle body speed correction circuit 18 is provided. Although the acceleration sensor A and the acceleration detection circuit 19 are added, they are not provided only in this embodiment but are generally provided in the ABS control circuit and are not shown. Nothing more. The other members having the same function are denoted by the same reference numerals and the description thereof will be omitted.

In this embodiment, as in the first embodiment, G
The speed signal obtained from the signal of the PS receiver and the wheel speed sensor S
_The wheel speed signal obtained by _{1 to} S ₄ is used as the speed difference calculation circuit 1
5. Find the feed speed difference.

The above speed difference may vary extremely when running on a bad road or when the tire pressure changes. In such a case, not know may be obtained the vehicle estimated speed V based on the which of the wheel speed SV ₁ Sv ₄ by the wheel speed sensor, accuracy decreases when referenced to large wheel speed errors.

Therefore, in such a case, when the estimated vehicle body speed is calculated in the ABS arithmetic control circuit 12 by the correction signal from the vehicle body speed correction circuit based on the speed based on the GPS signal, the estimated vehicle body speed is added. To correct.

When the vehicle body speed correction circuit 18 is used to obtain the estimated vehicle body speed, the correction may be performed in this correction circuit.

FIG. 5 is a schematic block diagram of the fourth embodiment. In this embodiment, the acceleration difference calculating circuit 16 is provided between the acceleration calculating circuit 16 and the acceleration determining circuit 17 of the second embodiment shown in FIG.
The difference from the second embodiment is that a is provided. It is premised that the acceleration detection circuit 19 is generally provided. The same functional members are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, unlike the second embodiment, the acceleration is basically determined based on the acceleration signal from the acceleration sensor provided in the automobile.

However, in the acceleration sensor, the offset level of the sensor output may change due to the temperature change of the environment. For example, an output corresponding to an acceleration of 0.2 G may occur due to temperature drift even when acceleration is not occurring.

Therefore, in this embodiment, the acceleration detection circuit 1
The acceleration difference detected by the acceleration signal is detected by the acceleration difference calculation circuit 16
Then, the difference from the acceleration value by the GPS signal is calculated. Then, for example, when the acceleration value of the GPS signal is 0, the output of the acceleration sensor is regarded as 0 to correct the acceleration value, and the difference from the output at that time is used as the acceleration of the vehicle body.

Then, using the above acceleration value, the acceleration judgment circuit 17 judges the acceleration value (a _i > similar to the second embodiment).
0.4G or a _i <0.4G).

FIG. 6 is a schematic block diagram of the fifth embodiment.
In this embodiment, the ABS control circuit of the first embodiment is
The difference is that a timer circuit 20 and a failure detection circuit 21 are added.

Then, when the block is not in operation, the GPS
Based on the estimated vehicle speed V obtained from the signal, when one or a plurality of speed SV ₁ Sv ₄ of the wheel speed sensor continues to output continuously a predetermined time or more above a certain speed difference, the timer The output of the circuit 20 is sent to the failure detection circuit 21, the target wheel speed sensor is judged to be in failure, and a signal is sent to a warning lamp to notify the driver of the abnormality.

FIG. 7 is a schematic block diagram of the sixth embodiment. This embodiment is the ABS control circuit 1 of the fourth embodiment of FIG.
0 is different only in that a failure detection circuit 21 and a warning light 22 are additionally provided. Although not shown, the failure detection circuit 21 includes an acceleration determination circuit.

In this embodiment, when the acceleration value obtained by the acceleration detection circuit 19 from the acceleration sensor A differs from the acceleration value obtained from the GPS signal by a certain amount or more, the acceleration sensor A is regarded as abnormal and the failure detection circuit. The signal from 21 turns on the warning light and informs the driver of the abnormality.

Although an example in which the ABS control circuit 10 is composed of a plurality of circuit blocks has been shown above, the same operation can be achieved even if some of these blocks are implemented by software in the ABS operation control circuit.

[0063]

As described above in detail, the antilock electronic control method of the present invention obtains not only the speed and acceleration information detected by the wheel speed sensor and the acceleration sensor but also the speed and acceleration information based on the GPS signal. As a result, ABS control can be performed by using highly reliable speed and acceleration values under various conditions. Therefore, control performance is improved and failure detection of various sensors is also possible, thus improving reliability. There are various advantages that can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an antilock control circuit according to a first embodiment.

FIG. 2 Flowchart of the above

FIG. 3 is a schematic block diagram of an antilock control circuit according to a second embodiment.

FIG. 4 is a schematic block diagram of an antilock control circuit according to a third embodiment.

FIG. 5 is a schematic block diagram of an antilock control circuit according to a fourth embodiment.

FIG. 6 is a schematic block diagram of an antilock control circuit according to a fifth embodiment.

FIG. 7 is a schematic block diagram of an antilock control circuit according to a sixth embodiment.

[Explanation of symbols]

 1 Antenna 2 GPS Receiver 3 Memory 4 Speed Calculation Circuit 10 ABS Control Circuit 11 Wheel Speed Detection Circuit 12 ABS Calculation Control Circuit 13 Drive Circuit 15 Speed Difference Calculation Circuit 16 Acceleration Calculation Circuit 17 Acceleration Judgment Circuit

Claims (6)

[Claims] 1. A speed information signal detected by a wheel speed sensor is sent, and a wheel speed, an acceleration, an estimated vehicle speed, an acceleration, etc. are obtained based on the speed information signal according to a predetermined calculation program, and as a result, the wheel is locked or locked. In the anti-lock electronic control method, which releases the braking when there is a tendency, re-brakes when the lock or the locking tendency disappears, and controls the braking of the wheels so as to repeat this as necessary, is transmitted from a plurality of artificial satellites. Based on the information of the position of the traveling vehicle detected by receiving the radio wave by the GPS receiver, either or both of the vehicle speed and the acceleration are obtained by calculation, and under a certain condition, based on the vehicle speed and the acceleration signal by the received signal. An anti-lock electronic control method characterized by controlling braking of a wheel by means of a steering wheel. 2. The antilock electronic control method according to claim 1, wherein the reception speed or acceleration signal is obtained from a navigation device that detects and displays position information of a vehicle. 3. A vehicle speed value obtained by estimating from the rotational speed of the wheel is corrected using the speed signal received by the GPS receiver, and the estimated vehicle speed is used for control. The anti-lock electronic control method according to claim 1 or 2. 4. The vehicle speed estimated based on the rotation speed of the wheel and the signal of an acceleration sensor mounted on the vehicle is corrected by using a speed calculation value from the GPS receiver,
The antilock electronic control method according to claim 1 or 2, wherein the control is performed using an estimated vehicle speed based on the speed information. 5. The estimated acceleration of the vehicle estimated from the rotation speed of the wheel is corrected by using the acceleration value from the GPS receiver, and the estimated acceleration is controlled. Alternatively, the anti-lock electronic control method according to item 2. 6. The acceleration estimated based on the rotation speed of the wheel and the signal of the acceleration sensor is corrected by using the acceleration value from the GPS receiver, and the estimated acceleration is used for control. The anti-lock electronic control method according to claim 1 or 2.