Method for determining the drowsiness or attention level of the driver of a road vehicle, and road vehicle thereof

1 . A method for determining the drowsiness/attention level of the driver (DR) of a road vehicle ( 1 ); the method comprises the steps of:

detecting at least one steering parameter (S) related to the kinematics of a driver-operated device (DR) for steering; wherein the steering parameter (S) is related to the steering angle (δ) and/or the steering speed (ω) of the road vehicle ( 1 );

elaborating a steering index (IS) as a function of the at least one steering parameter (S) detected;

detecting at least one line parameter (L) related to the position (P) of the road vehicle ( 1 ) within a lane ( 8 );

processing a line index (IL) as a function of the at least one line parameter (L) detected; and

processing a driver (DR) drowsiness/attention index (IDA) as a function of a combination of the steering index (IS) and the line index (IL);

adjusting the drowsiness/attention index (IDA) by a sensitivity function (SF) that increases or decreases the value of the drowsiness/attention index (IDA) as a function of boundary conditions comprising at least one of: driving duration, time of day, presence of passengers in the road vehicle ( 1 ), or use of driving assistants; and

when the drowsiness/attention index (IDA) as adjusted by the sensitivity function (SF) exceeds a predetermined threshold, actuating actuators to provide braking and/or haptic feedback;

characterized in that the steering index (IS) and/or the line index (IL) are calculated as a function of a respective punctual detection (PIS, PIL) of the steering parameter (S) and/or the line parameter (L) respectively and a respective base detection (BIS, BIL) of the steering parameter (S) and/or the line parameter (L) respectively; and

further characterized in that the punctual detection (PIS) of the steering parameter (S) is calculated as a function of the square root of the sum of the squares of the steering angle (δ) and the steering speed (ω) according to formula: PIS=√(δ 2 +ω 2 ).

2 . The method according to claim 1 , wherein the steering index (IS) and/or the line index (IL) are calculated as a function of the difference between the respective base detection (BIS, BIL) and the respective punctual detection (PIS, PIL), in particular the steering index (IS) and/or the line index (IL) are calculated as the integral over time of the difference between the respective base detection (BIS, BIL) and the respective punctual detection (PIS, PIL).

3 . The method according to claim 1 , wherein the base detection (BIS) of the steering parameter (S) is calculated as a function of the average of the punctual detection (PIS) of the steering parameter (S) during a certain time interval (TI), in particular from the beginning (TO) of the driving to the current time (AT).

4 . The method according to claim 1 , wherein the base detection (BIL) of the line parameter (L) is calculated as a function of the frequency of critical manoeuvres (CM) performed by the driver (DR) during a given time interval (TI), in particular from the start (TO) of driving to the current time (AT).

5 . The method according to claim 1 , wherein the punctual detection (PIL) of the line parameter (L) is calculated as a function of the frequency of critical manoeuvres (CM) performed by the driver (DR) during a moving time window (WS) ranging from the current time (AT) to a past time (PT).

6 . The method according to claim 5 , wherein the moving time window (WS) is greater than one minute.

7 . The method according to claim 1 , wherein the drowsiness/attention index (IDA) of the driver (DR) is calculated as a function of a driving index, which is given by the weighted sum of the steering index (IS) and the line index (IL); in particular, the weight of the steering index (IS) and the weight of the line index (IL) are defined by means of experimental tests.

8 . The method according to claim 4 , wherein the critical manoeuvres (CM) comprise:

a departure beyond a first threshold value (TVD) from the ideal trajectory (TJ) of the vehicle ( 1 ) within the lane ( 8 ); and/or

an excessive approach to the lines ( 11 ) demarcating the lane ( 8 ); and/or

a sudden correction that returns the road vehicle ( 1 ) to its optimum trajectory.

9 . The method according to claim 1 , wherein the detection of the steering parameter (S) and the line parameter (L), or the calculation of the drowsiness/attention index (IDA), is interrupted depending on the road travelled by the road vehicle ( 1 ) and/or depending on the driving style of the driver (DR); in particular, the detection of the steering parameter (S) and the line parameter (L), or the calculation of the drowsiness/attention index (IDA), are interrupted while driving through curves (C) and/or if the driver (DR) has a sporty or hazardous driving style.

10 . The method according to claim 1 and comprising the further step of alerting the driver (DR) if the drowsiness/attention index exceeds a second threshold value (TVI).

11 . A road vehicle ( 1 ) comprising:

four wheels ( 2 , 3 ), of which at least one pair is driven;

first sensors devices ( 4 ) configured to detect at least one steering parameter (S) related to the kinematics of a driver-operated device (DR) for steering; where the steering parameter (S) is related to the steering angle (δ) and/or the steering speed (ω) of the road vehicle ( 1 );

second sensors devices ( 7 ) configured to detect at least one line parameter (L) relative to the position (P) of the road vehicle ( 1 ) within a lane ( 8 ); and

an electronic control unit ( 9 ) configured to receive sensor signals for:

processing a steering index (IS) according to the at least one steering parameter (S) detected; and a line index (IL) according to the at least one line parameter (L) detected;

processing a driver (DR) drowsiness/attention index (IDA) as a function of a combination of the steering index (IS) and the line index (IL) by adjusting the drowsiness/attention index (IDA) using a sensitivity function (SF) that increases or decreases the value of the drowsiness/attention index (IDA) as a function of boundary conditions comprising at least one of: driving duration, time of day, presence of passengers in the road vehicle ( 1 ), or use of driving assistants; and

when the drowsiness/attention index (IDA) as adjusted by the sensitivity function (SF) exceeds a predetermined threshold, actuating actuators to provide braking and/or haptic feedback;

characterized in that the steering index (IS) and/or the line index (IL) are calculated as a function of a respective punctual detection (PIS, PIL) of the steering parameter (S) and/or the line parameter (L) respectively and a respective base detection BIS, BIL) of the steering parameter (S) and/or the line parameter (L) respectively; and

further characterized in that the punctual detection (PIS) of the steering parameter (S) is calculated as a function of the square root of the sum of the squares of the steering angle (δ) and the steering speed (ω) according to formula: PIS=√(δ 2 +ω 2 ).

12 . The road vehicle ( 1 ) according to claim 11 , wherein the first sensors devices ( 4 ) comprise sensors elements ( 10 ) at the wheels ( 2 , 3 ) and/or steering; and wherein the second sensors devices ( 7 ) comprise cameras and/or radio or laser devices.