Anti-skid brake control device

• US 5,328,256 A
• Filed: 09/09/1992
• Issued: 07/12/1994
• Est. Priority Date: 09/09/1991
• Status: Expired due to Fees

• Current Assignee: Hitachi Automotive Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Automotive Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Ohta, Kenji, Shimada, Kousaku, Sugawara, Hayato
• Primary Examiner(s): Graham, Matthew C.
• Application Number:
  US07/942,209
• Time in Patent Office: 671 Days
• Field of Search: 303/100, 303/110, 303/96, 303/103, 303/104, 303/105, 303/111, 364/426.02
• US Class Current: 303/146
• CPC Class Codes: B60T 8/1764 Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split or between front and rear
• CPC Class Codes: B60T 8/505 Pressure reapplication in a mu-split situation, i.e. a situation with different coefficients of friction on both sides of the vehicle

Abstract

An anti-skid brake control device has a control circuit 6 to which signals from a steering angle sensor 14, a yaw detector 7 and respective wheel velocity sensors 3a˜3d of a motor vehicle are inputted, an oil pressure actuator 5 controls of the pressure of the braking fluid for respective wheel cylinders 2a˜2d based upon target slip rates Sfrt. Sflt, Srrt and Srlt and measured slip rates Sfr, Sfl, Srr and Srl for the respective wheels calculated in the control circuit 6. The target slip rates for the respective wheels, which are principally determined dependent upon the deviation β between compensated target yaw angular acceleration ωR and measured yaw angular acceleration ω, are set independently and are modified dependent upon the motor vehicle body velocity, whereby the braking forces for the respective wheels are independently controlled . In this way, it is possible to suppress generated yaw moment and to improve stability of the motor vehicle, while also safely reducing the braking distance.

Claims

1. An anti-skid brake control device comprising,

means for detecting the respective velocities of a plurality of wheels of a motor vehicle;

means for detecting yaw angular acceleration of the motor vehicle;

means for detecting steering angle speed of a steering wheel of the motor vehicle to determine a target yaw angular acceleration;

target slip rate setting means for setting target slip rates individually for the respective wheels based upon the detected yaw angular acceleration and the determined target yaw angular acceleration, said target slip rate setting means including means for varying the set value of the target slip rate dependent upon at least one of a value of motor vehicle body velocity and a predetermined lapse of time after a yaw moment is generated; and

means for controlling pressures of braking fluid for the respective wheels so as to follow slip rates of the respective wheels determined on the basis of the respective wheel velocities detected by said wheel velocity detecting means and the varied set target slip rates for the respective wheels.

2. An anti-skid brake control device comprising,

means for detecting the respective velocities of a plurality of wheels of a motor vehicle;

means for detecting yaw angular acceleration of the motor vehicle;

means for determining target slip rates for the right and left side wheels independently based upon a steering angle signal of the motor vehicle and for correcting the determined target slip rates on the basis of the detected yaw angular acceleration; and

means for controlling braking pressures of the braking fluid for the respective wheels so as to follow slip rates of the respective wheels determined on the basis of the wheel velocities detected by said wheel velocity detecting means and the corrected target slip rates.

3. An anti-skid brake control device comprising:

first means for determining a target yaw angular acceleration ω

T based upon a steering angle speed θ

of a steering wheel of a motor vehicle;

second means for compensating the target yaw angular acceleration ω

T by applying a delay factor in the system of the device to obtain a compensated target yaw angular acceleration ω

R;

third means for detecting yaw angular acceleration ω

of the motor vehicle;

fourth means for determining a yaw angular acceleration deviation δ

by subtracting the detected yaw angular acceleration ω

from the compensated target yaw angular acceleration ω

R;

fifth means for determining target slip rates Sfrt, Sflt, Srrt and Srlt for the respective wheels based upon the yaw angular acceleration deviation δ

; and

sixth means for controlling pressures of braking fluid for the respective wheels in such a manner that slip rates of the respective wheels determined by the respective wheel velocities and motor vehicle body velocity follow the target slip rates for the respective wheels, wherein said fifth means includes a plurality of maps for determining the target slip rate for each of the respective wheels, which maps are selectable dependent upon at least one of a value of motor vehicle body velocity and a predetermined lapse of time after a yaw moment is generated, so that both stability of the motor vehicle and reduction in braking distance are safely obtained.