Method and device for ascertaining a driver state

1. A method for ascertaining a variable representing at least an alertness of a driver, the method comprising:

identifying the driver;

retrieving a profile of the driver, the profile including at least one of: the variable representing at least the alertness of the driver determined in a preceding vehicle operating cycle, or at least one value used for ascertaining the variable representing at least the alertness of the driver in the preceding vehicle operating cycle; and

ascertaining, for a current vehicle operating cycle, the variable representing at least the alertness of the driver as a function of the at least one of: the variable representing at least the alertness of the driver determined in the preceding vehicle operating cycle, or the at least one value used for ascertaining the variable representing at least the alertness of the driver in the preceding vehicle operating cycle.

2. The method as recited in claim 1 , wherein the variable representing at least the alertness of the driver for the current vehicle operating cycle is determined additionally as a function of a further variable which represents a level of activeness of the driver.

3. The method as recited in claim 1 , wherein the ascertaining the variable representing at least the alertness of the driver uses at least one of: a neural network, or a classifier.

4. The method as recited in claim 1 , wherein the identifying the driver is performed at a start of the current vehicle operating cycle.

5. The method as recited in claim 1 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of at least one of: a behavior of the driver to perform lateral control of the vehicle, or a performance of the driver to keep the vehicle inside a traffic lane.

6. The method as recited in claim 1 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of at least one of: an actuation of an operating element by the driver, or an interaction of the driver with the vehicle via at least one of a human-machine-interface or an infotainment system.

7. The method as recited in claim 1 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of a variable representing a physiological state of the driver.

8. The method as recited in claim 7 , wherein the variable representing the physiological state of the driver includes at least one of: a body temperature, a heartbeat frequency, or a pupil dilation.

9. The method as recited in claim 1 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of driving information.

10. The method as recited in claim 9 , wherein the driving information includes at least one of: an already elapsed driving time, a brightness to which the driver is exposed, a time of a day, or a temperature to which the driver is exposed.

11. The method as recited in claim 1 , further comprising storing the ascertained variable representing at least the alertness of the driver for the current operating cycle in the driver profile.

12. The method as recited in claim 1 , further comprising:

receiving additional information related to at least one of: the driver, or a trip,

wherein the ascertaining the variable representing at least the alertness of the driver is further a function of the additional information.

13. A device for ascertaining a variable representing at least an alertness of the driver, the device comprising:

a control unit including a processor configured to perform the following:

identifying the driver;

retrieving a profile of the driver, the profile including at least one of: the variable representing at least the alertness of the driver determined in a preceding vehicle operating cycle, or at least one value used for ascertaining the variable representing at least the alertness of the driver in the preceding vehicle operating cycle; and

ascertaining, for a current vehicle operating cycle, the variable representing at least the alertness of the driver as a function of the at least one of: the variable representing at least the alertness of the driver determined in the preceding vehicle operating cycle, or the at least one value used for ascertaining the variable representing at least the alertness of the driver in the preceding vehicle operating cycle.

14. The device as recited in claim 13 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of at least one of: a behavior of the driver to perform lateral control of the vehicle, or a performance of the driver to keep the vehicle inside a traffic lane.

15. The device as recited in claim 13 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of at least one of: an actuation of an operating element by the driver, or an interaction of the driver with the vehicle via at least one of a human-machine-interface or an infotainment system.

16. The device as recited in claim 13 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of a variable representing a physiological state of the driver, the variable representing the physiological state of the driver including at least one of: a body temperature, a heartbeat frequency, or a pupil dilation.

17. The device as recited in claim 13 , wherein the ascertaining the variable representing at least the alertness of the driver is further a function of driving information, the driving information including at least one of: an already elapsed driving time, a brightness to which the driver is exposed, a time of a day, or a temperature to which the driver is exposed.

18. The device as recited in claim 13 , wherein the processor is configured to store the ascertained variable representing at least the alertness of the driver for the current operating cycle in the driver profile.