Method of correcting steering of a road driven vehicle
First Claim
1. A method for automatically correcting steering of a road vehicle by a driver, the driver controlling a steering wheel of the vehicle by an angle δ
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H (in radian), the vehicle having a wheelbase l(in m), a center of gravity (CG) disposed a distance lF (in m) from the front axle and a distance lR (in m) from the rear axle, a mass m (in kg), a moment of inertia J (in kg m3) around a vertical axis through the center of gravity, and a steering gear ratio iL ;
the method comprising;
providing a controller and sensors;
measuring a yaw velocity r (in radian/s) around the vertical axis with the yaw rate sensor;
determining a driving speed vx (in m/s) via the ABS sensor;
measuring an acceleration ax (in m/s2) in the driving direction with an accelerometer;
measuring a lateral acceleration, the acceleration being counted as positive to the left, with two accelerometers mounted at two convenient locations at a distance la in the longitudinal vehicle direction as ay1, (in m/s2, front) and ay2 (m/s2, rear);
measuring a steering wheel angle δ
H with a potentiometer or a capacitive sensor on a steering column of the vehicle, the angle being measured in radians counting positive to the left;
computing a vehicle wheel angle δ
L =δ
H /iL controlled by the driver;
computing a variable angle β
F at the front axle according to a the known observer method; and
computing in a microprocessor of the controller according to the differential equation ##EQU48## where δ
C denotes a supplemental steering angle which, when added to the vehicle wheel angle δ
L controlled by the driver results in the overall wheel angle δ
F =δ
L +δ
C ;
where δ
1, denotes a computer-internal controller state;
where u1 denotes a first input for further feedback signals and u2 denotes a second input for further feedback signals; and
where F1 (δ
L) and F2 (δ
L) denote prefilters which are functions of the vehicle wheel angle δ
L.
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Accused Products
Abstract
To support the driver of a road vehicle, a yaw velocity r (in radian/s) around a vertical axis is measured, a driving speed vx (in m/s) is determined, an acceleration ax (in m/s2) in the driving direction is measured, a lateral acceleration is measured at two randomly selected locations at a distance of la as ay1 (in m/s2, front) and ay2 (m/s2, rear), a steering wheel angle δH is measured at the vehicle steering column with a potentiometer, a vehicle wheel angle δL =δH /iL commanded by the driver is computed, a variable angle βF at the front axis is computed, and these measured parameters are used to calculate, in a microprocessor, according to the equations (4, 20 and 21), an additional steering angle δC, whose addition to the vehicle wheel angle δL commanded by the driver results in the overall wheel angle δF =δL +δC.
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Citations
11 Claims
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1. A method for automatically correcting steering of a road vehicle by a driver, the driver controlling a steering wheel of the vehicle by an angle δ
-
H (in radian), the vehicle having a wheelbase l(in m), a center of gravity (CG) disposed a distance lF (in m) from the front axle and a distance lR (in m) from the rear axle, a mass m (in kg), a moment of inertia J (in kg m3) around a vertical axis through the center of gravity, and a steering gear ratio iL ;
the method comprising;providing a controller and sensors; measuring a yaw velocity r (in radian/s) around the vertical axis with the yaw rate sensor; determining a driving speed vx (in m/s) via the ABS sensor; measuring an acceleration ax (in m/s2) in the driving direction with an accelerometer; measuring a lateral acceleration, the acceleration being counted as positive to the left, with two accelerometers mounted at two convenient locations at a distance la in the longitudinal vehicle direction as ay1, (in m/s2, front) and ay2 (m/s2, rear); measuring a steering wheel angle δ
H with a potentiometer or a capacitive sensor on a steering column of the vehicle, the angle being measured in radians counting positive to the left;computing a vehicle wheel angle δ
L =δ
H /iL controlled by the driver;computing a variable angle β
F at the front axle according to a the known observer method; andcomputing in a microprocessor of the controller according to the differential equation ##EQU48## where δ
C denotes a supplemental steering angle which, when added to the vehicle wheel angle δ
L controlled by the driver results in the overall wheel angle δ
F =δ
L +δ
C ;
where δ
1, denotes a computer-internal controller state;
where u1 denotes a first input for further feedback signals and u2 denotes a second input for further feedback signals; and
where F1 (δ
L) and F2 (δ
L) denote prefilters which are functions of the vehicle wheel angle δ
L. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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H (in radian), the vehicle having a wheelbase l(in m), a center of gravity (CG) disposed a distance lF (in m) from the front axle and a distance lR (in m) from the rear axle, a mass m (in kg), a moment of inertia J (in kg m3) around a vertical axis through the center of gravity, and a steering gear ratio iL ;
Specification