Method and device for diagnosing in a motor vehicle a driver's fitness drive

[0001] The invention relates to a method for diagnosing the driving capability of a driver in a motor vehicle, in which changes in driver condition are ascertained from physiological measured values derived from the driver while driving in the vehicle, and if the changes are serious, a warning is issued or remedial actions are initiated; as well as an apparatus for performing this method.

[0002] Systems which appraise the driver's condition on the basis of physiological parameters measured in the vehicle are known. These include, for example, interactive systems that request from the driver, while driving, certain input actions on the basis of which the driving capability of the driver is determined. Systems also exist which sense the eyelid blink frequency by way of a video camera with downstream image analysis. From the acquired blink frequency, conclusions can in turn be drawn regarding the driving capability of a driver in the motor vehicle.

[0003] Also available in the home context are systems, for example exercise machines equipped with ergometric functions, which allow conclusions as to the health of the user by way of physiological measured values such as blood pressure, pulse rate, skin impedance, etc.

[0004] The informativeness of systems that are currently known or under development in terms of assessing the driving capability of the driver in a motor vehicle is considerably limited, however, by the fact that the only methods possible are those that do not use fixed electrodes or catheters on the driver's body, but instead must make do with contacts on bare skin areas or with entirely non-contact measurements, such as the aforesaid acquisition of the eyelid blink frequency by means of a video camera.

[0005] It is the object of the invention to increase the reliability and informativeness of a method of the species for diagnosing the driving capability of a driver of a motor vehicle in order, as applicable, to output to the driver a warning based on the diagnosis of driving capability and to initiate remedial actions if necessary.

[0006] According to one significant aspect, in the context of the method according to the present invention the physiological measured values measured instantaneously while driving are combined with stationary health-relevant data for the driver ascertained in the home context, and are weighted and interpreted by an expert system with data, present in the vehicle or derived, indicating driver stress, in particular concerning the instantaneous traffic situation and the instantaneous vehicle operating state or changes in the driver's condition.

[0007] This makes it possible to use the data obtained in the vehicle from the vehicle operating state and from the instantaneous traffic situation to derive an estimated value regarding the instantaneous driver stress, with which the instantaneous physiological data about the driver measured while driving in the vehicle, and the stationary health-relevant data obtained in the home context and combined therewith, can then be weighted and interpreted in a more informative fashion to yield a comprehensive appraisal of the driver's driving capability.

[0008] Circulatory data such as the driver's pulse rate and blood pressure are particularly suitable for the acquisition of physiological values for the driver in the vehicle. Such circulatory data can easily be obtained with already known transducers, for example, in the form of a wristwatch, and transmitted wirelessly to a receiver in the vehicle.

[0009] Also suitable is measurement in the vehicle of the driver's skin impedance. This physiological value can also be obtained using already known transducers that are attached to the driver's skin, and transmitted wirelessly to a receiver in the vehicle.

[0010] Mention has also already been made of the possible measurement, using a video camera with downstream image processing, of the eyelid blink parameter, i.e. the driver's blink frequency and speed, which can provide clear information about driver fatigue.

[0011] An estimate of the instantaneous stress on the driver as a result of the situation in terms of driving, traffic, and the environment can be made from data that are derivable or present in any case in the vehicle. For example, data from a destination guidance system can be used. These indicate the static traffic situation in which the driver finds him- or herself, e.g. urban, rural, at a complex intersection, on a narrow mountain road. Information regarding the dynamic traffic situation is obtained from road condition data, weather data, and time of day; by way of the sensed speed of the particular vehicle, for example acceleration values and frequency; and from the speed of other vehicles, for example based on ACC signals. An estimate of the instantaneous traffic density, based on ACC data and using future video sensor apparatus, appears possible in principle.

[0012] In the method according to the present invention, the estimate that is made of the instantaneous driver stress is combined, by the use of an expert system, with the instantaneous physiological situation of the driver as supplied by the aforementioned physiological data acquired with the use of a driver condition sensor suite. As a result of this association, it is possible to determine how the stress due to driving is reflected in the physiological data. It is assumed in this context that other influences, for example interaction with passengers or in conversations by mobile telephone in traffic, have much less of an influence on the driver's stress level. Stress resulting from driving serves, in a way, as an ergometer with which a patient, i.e. in this case the driver, is brought into a known stress situation. The difference here is also that driving represents more a mental and psychological stress than a physical one. From the physiological reaction of the driver's body to this stress, conclusions can then be drawn as the state of the driver's health. For example, extreme systolic blood-pressure values and rapid pulse rates may occur, and a determination can be made as to whether they are correlated with difficult traffic situations or are occurring without such stresses. In the latter case, the driver can be warned and can be advised to seek medical help. Information as to excessive fatigue or drugs (such as blood alcohol level) can be obtained in known fashion from measured values of the driver condition sensor suite operated in the vehicle. As a result of this weighting with the driver stress estimated from the traffic situation and from the vehicle operating status, considerably better conclusions can be drawn as to the relevance of this information.

[0013] In the method according to the present invention, as mentioned, the instantaneous physiological data obtained using the mobile driver condition sensor suite in the vehicle are also combined with health-relevant data for the driver ascertained on a stationary basis. Stationary health data of this kind can be ascertained, for example, using home-based systems that are capable of obtaining from the user's (in this case the driver's) biological material, such as urine, feces, sweat, etc., information about the person's state of health. Health-relevant data can also be collected and stored in home health devices, for example bicycle ergometers, exercise machines, blood-sugar measurement instruments, scales, etc. These stationary data are usually obtained in static situations or during muscle work, and not predominantly under mental/psychological stress such as occurs in a motor vehicle. The stationary data can be stored in a suitable storage/transfer medium, and the latter can be read by an input means in the vehicle or the stored information can be sent to a receiver in the vehicle. This memory/transfer medium can be, for example, a chip card, a wristwatch with wireless transmission technology, a mobile radio system, or the like.

[0014] The expert system in the motor vehicle weights the instantaneous physiological data (obtained while driving using the mobile driver condition sensor suite) with the driver's health-relevant data obtained in stationary fashion, and thereby obtains a more comprehensive picture of the driver's state of health, so that in the event of serious deviations from normal values, remedial actions can be initiated as applicable.

[0015] In the event no stationary measured values concerning the driver's state of health in the home context can be obtained, standard values are assumed by the diagnostic method proposed according to the present invention, and those standard values are refined using inputted biographical data such as the driver's gender, age, and weight.

[0016] In an embodiment, the expert system can be set up as a learning system; initially, before a valid diagnosis as to driving capability is issued, a learning phase with at least one test drive by the driver is performed in the vehicle, comprising a variety of stress levels and traffic situations.

[0017] An apparatus set up to carry out the method contains the expert system implemented in an onboard computer of the vehicle, and the onboard computer is connected via a vehicle bus system to the driver condition sensor suite which supplies the physiological measured values; to a memory/transfer means that delivers the biographical data and/or health-relevant data ascertained in stationary fashion; to means that estimate the driver stress based on the instantaneous traffic situation and the instantaneous vehicle operating state and transmit it to the onboard computer; and also to means that impart to the driver as a warning signal, or that emit to the environment, a signal indicating an overload or a driver stress that is not appropriate for the situation. An ACC system and a vehicle navigation system can be used to ascertain the instantaneous traffic situation and to appraise the driver stress. In order to identify the driver, the onboard computer and the expert system residing therein can be connected to a vehicle access authorization control unit.

[0018] The description below describes, with reference to a functional block diagram depicted in the FIGURE, steps of a driver diagnosis method according to the present invention, as well as functions of an exemplary embodiment of an apparatus set up to carry out the method.

[0019] System 1, depicted in the FIGURE in the form of functional blocks, includes the following functional units:

[0020] an expert system 10 implemented in an onboard computer;

[0021] an ACC and navigation system 11 having associated sensors 2a, 2b and a radio antenna 2c;

[0022] means 12 for acquiring the stationary (at-home) physiological data of a driver;

[0023] means 15, 18 for storing/transferring to the onboard computer the health-relevant data obtained in stationary fashion;

[0024] a vehicle bus system 3 for connecting various units in the vehicle; and

[0025] a driver condition sensor suite 4 located in vehicle 5.

[0026] An optionally provided driver access authorization control unit is not depicted.

[0027] Sensors 2a, 2b associated with ACC and navigation system 11, and radio antenna 2c, serve to acquire environmental/traffic situation 20, for example via radar waves, video image acquisition, and/or ultrasonic waves, and to receive driving direction information via GSM mobile radio. In ACC and navigation system 11, ACC information 20 acquired by the corresponding sensors 2a, 2b and antenna 2cfor example the number, speed, and heading of other vehicles, and driving direction information; also the vehicle's own heading and speed, road category, urban/rural, weather data, road condition, topographic data, etc.is ascertained, and the driver stress is estimated therefrom and transmitted in the form of a signal 14 to expert system 10 in the onboard computer. Expert system 10 also receives, from mobile driver condition sensor suite 4, signals 17 that indicate the physiological data for the driver in the vehicle acquired by driver condition sensor suite 4. The physiological data ascertained in stationary home-based system 12, as well as biographical data, are inputted via memory/transfer medium 15 (i.e. a chip card), using an input/read medium 18, into expert system 10. In the latter, the stationary health data thus inputted are combined with the instantaneous physiological data 17 for the driver acquired by mobile driver condition sensor suite 4 while driving, weighted with estimated value 14 for driver stress, and interpreted.

[0028] Expert system 10 weights the physiological and biographical data with the estimated driver stress 14 and, if the changes in driver condition are serious, generates a warning for the driver and/or a signal 13, e.g. emittable externally via GSM radio, which indicates the overload or situationally inappropriate stress on the driver so that remedial actions can be initiated. In one embodiment, the onboard computer or expert system can be connected to a driver access authorization control unit which performs the identification of the driver and delivers it to the expert system.

[0029] The core of the method according to the present invention, and of the apparatus according to the present invention set up to carry out the method, is thus the combination, performed by the expert system, of physiological data 17 (obtained while driving by way of driver condition sensor suite 4) with the stationary health-relevant data obtained in the home context and delivered via memory/transfer medium 15, and the weighting of these combined data using an estimated value 14 that indicates driver stress, which is estimated as an independent variable based on the traffic situation and driving direction information obtained from the onboard ACC and navigation system 12 and is delivered to expert system 10. From the weighted change in driver condition, expert system 10 decides if that change is so serious that driving capability is questionable, if a warning signal needs to be issued to the driver, or if applicable remedial actions need to be initiated.

[0030] In the exemplary embodiment described above, expert system 10 resides in an onboard computer of a vehicle 5. The method according to the present invention is not, however, limited to this currently preferred exemplary embodiment, but rather is also usable if expert system 10 resides outside vehicle 3 at a central location, to which the physiological data ascertained by way of the mobile driver condition sensor suite, the stationary physiological and biographical data, and the information about the traffic situation and the driving direction information ascertained from the ACC system and navigation system 12 are then conveyed.

[0031] The invention was described above for an application aimed at ascertaining the driving capability of the driver of a motor vehicle. It is nevertheless immediately apparent to those skilled in this art that the invention is also applicable to operating capability diagnosis in the context of drivers (or pilots) of other vehicles and means of transportation, for example ships, aircraft, and rail vehicles. The term motor vehicle or vehicle used in the above description and in the Claims is thus to be construed broadly.