Method of correcting steering of a road driven vehicle

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 .delta..sub.H (in radian), the vehicle having a wheelbase l(in m), a center of gravity (CG) disposed a distance l.sub.F (in m) from the front axle and a distance l.sub.R (in m) from the rear axle, a mass m (in kg), a moment of inertia J (in kg m.sup.3) around a vertical axis through the center of gravity, and a steering gear ratio i.sub.L ;

• 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 v.sub.x (in m/s) via the ABS sensor;
• measuring an acceleration a.sub.x (in m/s.sup.2) 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 l.sub.a in the longitudinal vehicle direction as a.sub.y1, (in m/s.sup.2, front) and a.sub.y2 (m/s.sup.2, rear);
• measuring a steering wheel angle .delta..sub.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 .delta..sub.L =.delta..sub.H /i.sub.L controlled by the driver;
• computing a variable angle .beta..sub.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 .delta..sub.C denotes a supplemental steering angle which, when added to the vehicle wheel angle .delta..sub.L controlled by the driver results in the overall wheel angle .delta..sub.F =.delta..sub.L +.delta..sub.C ;
• where .delta..sub.1, denotes a computer-internal controller state;
• where u.sub.1 denotes a first input for further feedback signals and u.sub.2 denotes a second input for further feedback signals;
• and where F.sub.1 (.delta..sub.L) and F.sub.2 (.delta..sub.L) denote prefilters which are functions of the vehicle wheel angle .delta..sub.L.