Patent ID: 7283056

Claim:
A method for determining when a driver of a vehicle is inattentive, said method comprising: detecting movement of a steering wheel of the vehicle in the form of a steering wheel angle x; detecting occurrence of a steering quiescent phase; determining an extent, in terms of time duration, of the steering quiescent phase, based on at least one of the detected steering wheel angle and a rate of change of said steering wheel angle; identifying a steering action following the steering quiescent phase; determining the extent of the steering action by evaluating the rate of change of the steering wheel angle; and determining a measure of severity of driver inattentiveness, based on the result of a link between the extent of the steering quiescent phase and the extent of the steering action; wherein, the extent of the steering quiescent phase is determined as a time period during which the steering wheel angle remains within a predetermined steering wheel angle interval; the extent of the steering action following a previous steering quiescent phase is determined in the form of the maximum gradient of the steering wheel angle which then occurs; the link between the extent of the steering quiescent phase and the extent of the steering action at a time t 1 is produced by means of a multidimensional operator, only when the extent of the steering quiescent phase is greater than a predetermined minimum time and the maximum gradient of the steering wheel angle exceeds a predetermined gradient threshold value; a steering wheel angle interval is predetermined on the basis of the current speed of the vehicle; the multidimensional operator represents one of a family of characteristics, a weighting function and a logical decision function; the multidimensional operator is dimensioned based on at least one of the speed of the vehicle, and dynamics of a driving style of the driver of the vehicle; in a subsequent step a result of the logical operation is mapped in the form of the multidimensional operator onto a probability value P(U 1 ) between 0 and 100%, which represents the inattentiveness by the driver in the steering of the vehicle at the time t 1 ; and the method further comprises, determining a first probability vector O n=1 , whose elements O n=1,k1 each represent probability values P(O 1,k1 ), of a probability value P(U 1 ) occurring in individual, predetermined and selected extent levels k 1 where k 1 ε {1 . . . K 1 }; and determining a fatigue probability vector S′, whose elements each represent fatigue level probabilities P that detect driver inattentiveness is associated with individual, predetermined and suitably selected fatigue levels, using the following formula: S ′( t ) O 1 T ·B 1 ; (5), with O T 1 representing the transpose of the first probability vector; B 1 the matrix B representing predetermined conditional probabilities with respect to the steering inattentiveness, represented by the indicator n=1; and K 1 representing the number of extent levels for the indicator n=1.