Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
2000-04-28
2001-09-25
Zanelli, Michael J. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S078000, C303S167000
Reexamination Certificate
active
06295499
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of improving the control behavior of an anti-lock control system, in particular, of improving the steerability of the automotive vehicle and the driving stability during cornering, wherein a vehicle reference speed is derived from the rotating behavior of the wheels of the automotive vehicles and criteria are obtained for identifying a cornering situation and the curve direction, and once a cornering situation is identified, the standard control mode is replaced by a special or curve control mode which already in the partial deceleration area causes a direct or a indirect reduction in brake pressure on the front wheel at the inner side of the curve and/or on the rear wheel at the inner side of the curve.
DE 34 13 738 C2 already discloses an anti-lock control system provided with a system for identifying a cornering situation also based on wheel slip measurement. To identify a cornering situation, the slip values on the wheels at one vehicle side are summed up and compared to the slip values on the wheels at the other vehicle side, generating a cornering identification signal as soon as the difference of the summed-up slip values exceeds a predetermined threshold value. Upon identification of a cornering situation, selective criteria, such as “select-low” or “select high” according to which the course of pressure in the individual brake pressure control channels of the said brake system is controlled, and threshold values for rendering the said selective criteria effective, are varied. In this way, the control will be adjusted to the varying conditions during straight-forward driving and during cornering.
DE 21 19 590 A1 teaches to generate a cornering identification signal with the aid of a lateral accelerometer, such as a mercury switch.
Moreover, it is already known in the art to extend the functions of an anti-lock control system by employing the system for improving the driving stability or deceleration stability in the curve. For this purpose, during Cornering or during a partial deceleration, i.e. in a deceleration process in which the threshold of response to the anti-lock control system is not achieved, a stabilizing moment about the vertical axis of the vehicle is created by specifically delaying the brake pressure build-up on the wheels at the inner side of the curve compared to the brake pressure on the wheels on the outer side of the curve (“Bremsanlage und Schlupf-Regelsystem der neuen 7-er Reihe von BMW” (Brake System and Slip Control System of the new BMW No. 7 series); ATZ 97 (1995), pp. 8-15, and “Bremsanlage und Schlupf-Regelsysteme der neuen Baureihe 5 von BMW” (Brake System and Slip Control Systems of the new BMW No. 5 series); ATZ 98 (1996), pp. 188-194. The information on the actual steering angle is derived—if no steering angle sensor is used—from the lateral acceleration which, in turn, is calculated from the wheel sensor signals.
Now, it is the object of the invention to avoid, in a control system exclusively evaluating the wheel rotating signals also for cornering identification, the disadvantageous effects of “errors in identification”. For, exclusive reliance on the signals generated by the number of revolutions of the wheel may result in situations favoring errors in identification. This applies, for example, to cornering on :-split, i.e. on a varying right/left coefficient of friction if the inner side of the curve has a high coefficient of friction, while the outer side of the curve has a low coefficient of friction. In that situation, a stabilizing step interfering with the wheel allegedly on the inner side of the curve, could cause a destabilizing moment of yaw.
SUMMARY OF THE INVENTION
This object is achieved by a method involving that, upon initiation of the special control mode, re-acceleration of the wheel whose brake pressure was reduced as a result of the special control, i.e. of that wheel which, erroneously, was identified as a wheel located at the inner side of the curve, is analyzed for detecting such an error in identification. Once re-acceleration of the said wheel exceeds a predetermined threshold value, brake pressure is fed into the wheel brake of the said wheel as long as the threshold value is exceeded.
It has proved to be advantageous to dimension the duration of the brake pressure application for eliminating the undesired effects of an error in identification in accordance with the formula
t
DAi
=k
i
*(
a
i
−a
limit1
)
wherein a
limit1
is between 2 g and 5 g, e.g. 4 g.
According to another embodiment relating to a control system wherein the brake pressure, in case of control, is applied in pulses by opening an inlet valve, it has proved to be advantageous to increase the brake pressure in addition to the brake pressure share dimensioned according to the aforementioned formula, by a predetermined amount. For, the pressure build-up pulse joining the first pressure build-up pulse, is extended by an additional period of time determined by the second threshold value, namely
t
DAi
=k
2
*(
a
i
−a
limit2
)
wherein a
limit2
is between 1.5 g and 2.5 g. The brake pressure deficit on the wheel at the allegedly inner side of the curve developed as a result of the error in identification, in this way, is rapidly overcome without affecting to the stability of the control.
REFERENCES:
patent: 4844557 (1989-07-01), Giers
patent: 5272636 (1993-12-01), Buschmann et al.
patent: 5302010 (1994-04-01), Ehmer et al.
patent: 5312169 (1994-05-01), Buschmann
patent: 5494344 (1996-02-01), Heyn et al.
patent: 33 45 729 (1985-06-01), None
patent: 34 13 738 (1985-10-01), None
patent: 39 05 045 (1990-08-01), None
patent: 42 34 819 (1993-04-01), None
patent: 43 32 820 (1995-03-01), None
patent: 196 22 839 (1996-12-01), None
patent: 195 22 634 (1997-01-01), None
patent: 195 22 632 (1997-01-01), None
Publication from Bosch Technische Berichte—Antiblockiersystem (ABS) by Von Heinz Leiber et al. 1980.
Article from ATZ Automobiltechnische Zentschrift 98 (1996)—Bremsanlage und Schlupfregelungs-systeme der neuen Baureihe 5 von BMW by Kurz et al.
Article from ATZ Automobiltechnische Zentschrift 97 (1995)—Bremsanlage und Schlupf-Regelsysteme der neuen 7er-Reihe von BMW by Leffler et al.
Continental Teves AG & Co. oHG
Rader & Fishman & Grauer, PLLC
Zanelli Michael J.
LandOfFree
Method of improving ABS control behavior does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of improving ABS control behavior, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of improving ABS control behavior will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2514314