EP1169189A1

EP1169189A1 - Method and device for monitoring the driving proficiency of a person who is piloting a vehicle or a driving simulator

Info

Publication number: EP1169189A1
Application number: EP00913946A
Authority: EP
Inventors: Franz Wurz
Original assignee: Fahrertraining & Motorsportmanagement GmbH
Current assignee: Fahrertraining & Motorsportmanagement GmbH
Priority date: 1999-03-17
Filing date: 2000-03-17
Publication date: 2002-01-09
Also published as: AU3542800A; ATA47899A; WO2000055000A1

Abstract

The invention relates to a method and device for monitoring the driving proficiency of a driver, whereby the vehicle which is piloted by said driver comprises a hand-operated steering unit (1). The inventive device is characterized by having at least one sensor (2; 20) which is arranged on the steering unit (1) and which is provided for measuring the force with which the driver grips the steering unit, whereby the at least one sensor (2; 20) transmits an output signal (F(t)) that is proportional to the gripping force. The inventive device is also characterized by having a comparison device (3) for comparing the output signal (F(t)) transmitted by the gripping force sensor (2; 20) with an established upper limiting value (Fmax), whereby the comparison device (3) transmits a warning signal (W(t)) when the upper limiting value (Fmax) is exceeded. An optical, acoustic or tactile warning unit (4) is also provided which can be activated by the warning signal (W(t)). The invention makes it possible to detect the stressed and fatigued states of a driver in a timely manner, and to prevent accidents through the use of corresponding warning signals. The invention can also be used in motor sports and in driver training.

Description

METHOD AND DEVICE FOR MONITORING THE EQUIVALITY OF A PERSON CONTROLLING A VEHICLE OR A DRIVING SIMULATOR

The invention relates to a method and a device for monitoring the driving humidity of a person controlling a vehicle or a driving simulator, the vehicle or the driving simulator having a manually operable control device.

Controlling a vehicle has become an integral part of modern life. And although the handlebars are aware of their actions when steering, they consist of unconscious components: the handlebars automatically adjust the gripping forces to perform precise steering movements, they estimate correct braking forces to avoid collisions, etc. Controlled driving is also humane Factors such as emotions, stress and attention. Especially in the field of motorsport, the influence of these factors on driver performance is important for candidate selection, optimization of training and accident prevention. In addition, the factors mentioned also play a central role in driver training.

Science has recently dealt with the relationships between a driver's gripping crabs and his driving behavior, but is still at the beginning of a systematic research.

The results of experiments on gripping performance show that there is a difference between "power grip" and "precision gnff". Typically, a power grip occurs when you make a fist or hold a suitcase. With the power grip, the fingers contract at the same time in order to achieve the highest possible force. With the precision gnff only the thumb and the pointer are activated. Typically, this handle is used to pick up small objects or perform precise manipulative tasks.

The gripping patterns during the steering of motor vehicles cannot be clearly assigned to one of these grip definitions. If you put the driver's fingers considered, one is inclined to use the power grip definition. On the other hand, the manipulations on a steering wheel are precisely coordinated and thus have features of the precision handle. Furthermore, steering movements depend of course on the handlebar and the situation: there are straight sections where a car requires less control (a), there are curves where the steering wheel has to be turned fairly evenly (b), and there can be unexpected ones Provide situations where quick corrections are necessary (c). Different gripping patterns occur in each of these three situations: in (a) the driver's hands are less firmly attached to the steering wheel and the gripping forces are rather low, in (b) the gripping forces are higher to prevent the steering wheel from slipping, and at (c) the highest forces are expected to counteract unpredictable retransmitted forces.

The retransmission of forces that are associated with steering actions also has a significant influence on driving behavior, since it helps the driver to obtain information about vehicle dynamics and the interaction between vehicle and road, so that a kind of "body strategy" can be developed, where vehicle dynamics are treated as part of the body. Retransmitted forces are felt by the receptors in the fingertips and limbs and then coded and passed on to the sensory nerves. These signals reach different areas of the brain (brain stem, cerebellum / cerebellum), where comparisons are made with the downward efferent signals. If necessary, corrective movements are organized based on these internal comparisons. Furthermore, it is likely that such a mechanism serves to optimize the actions of the driver when steering, for example during driving training with a new autotype. However, it must be taken into account that signals from other sensory sources such as vision, vestibule / hearing / sense of balance and skin receptors on the seat also play a role. It has been shown that non-specific factors such as emotional state, stress and attention also affect motor control. For example, in an aggressive state, neuromuscular control becomes stiffer (more simultaneous contraction). Such a strategy can be beneficial to achieve a specific goal more quickly, but on the other hand it reduces flexibility in the behavioral repertoire, which can be disadvantageous in a complex situation. Stress can cause positive (eustress) but also negative feelings (distress).

The present invention builds on these findings and in particular sets the described non-specific factors of emotional state, stress and attention in correlation to the grip forces and gripping patterns that a driver places on a control device, in particular a steering wheel or a joystick, while driving or during a driving simulation , exercises.

Previously, a driver's attention was usually assessed with response time tests, but changes in eyelid frequency were also observed in motorists.

While - as mentioned - there are still many open questions for science regarding the relationship between gripping force or gripping pattern and driving behavior in the presence of certain non-specific factors, the inventors assume that their longstanding experience in motorsport and driving training means that there is an important relationship between gripping force and to have recognized the well-being or stressed state of a driver, namely that, generally speaking, the gripping force exerted on a control device is proportional to the excited state of the driver. So you know the effect of "clinging" to the steering wheel of novice drivers and inexperienced people, but even the experienced motor sportsman always comes into stressful situations in which he holds the steering wheel or the control stick inappropriately strong and thus tightens the hand and arm muscles, what is always associated with a decrease in the precision of the steering movements. The present invention builds on this finding and offers a method and a device for monitoring the ability to drive of a person controlling a vehicle or a driving simulator, the vehicle or the driving simulator having a manually operable control device.

The method according to the invention is characterized by the steps: a) determining the gripping forces with which the person holds the control device, b) comparing the gripping forces with a fixed upper limit value, and c) sending out a warning signal when the determined gripping forces reach the upper one Exceed the limit.

If the specified upper limit value is exceeded, it can be assumed that the driver is in a state of mind that is not optimal or even harmful for his steering behavior, without being generally aware of this. The driver is made aware of this condition by the warning signal and can now consciously take actions against it, for example active actions to relieve stress. However, the method according to the invention can also be used particularly effectively in driving training, since it signals the driving instructor to exceptional driving states of excitement, so that the student's insecurities can be quickly recognized and the driving situations that have led to such uncertainty can be specifically trained and weaknesses eliminated.

Since handlebars hold the steering wheel with different gripping forces, i.e. a so-called basic gripping force, even under normal driving conditions and states of mind, it has proven to be advantageous to improve the evaluation of the gripping force to determine an average value of the gripping forces under normal driving conditions, for example by integrating the current gripping forces a certain period of time, and subtract the determined average of the gripping forces from the instantaneous value of the gripping forces before their comparison with the upper limit value (Fmax) or the lower limit value (Fmin). These limit values can then be set independently of the basic grip strength of the respective driver In addition to cramping in stressful situations, combined with the "clinging" to the steering wheel, the correlation between gripping force and state of excitement can also be used to detect a lack of concentration and fatigue states, these states being manifested in that the gripping forces fall below a minimum.

An advantageous development of the method according to the invention therefore comprises the further steps d) comparing the gripping forces with a fixed lower limit value, and e) sending out a warning signal if the determined gripping forces fall below the lower limit value.

In summary, one can say that the gripping forces for safe driving behavior should be within a certain range. However, it is cheaper not to use the absolute values of the gripping forces for the calculation, but to relate external influences to them. For example, the gripping forces in fast corners can be significantly higher than on a straight road. A preferred embodiment of the method according to the invention is thus characterized in that the upper limit value and, if appropriate, the lower limit value are determined dynamically as a function of the deflection of the control device or of external driving parameters such as the vehicle speed, the steering angle and the condition of the roadway.

An optical, acoustic or tactile warning device is expediently activated with the transmitted warning signal.

In a development of the method according to the invention, the emitted activates

Warning signal an automatic control system that at least partially takes over control of the vehicle, the automatic control system expediently braking or stopping the vehicle. In addition, it can be provided that the automatic control system reacts to signals from at least one of an acceleration, a distance or a braking force sensor.

The invention also relates to a device for monitoring the ability to drive of a person controlling a vehicle or a driving simulator, the vehicle or the driving simulator having a manually operable control device.

This device is characterized by at least one sensor arranged on or in the control device for measuring the force with which the controlling person grips the control device, the at least one sensor providing an output signal proportional to the gripping force, and a comparison device for comparing the output signal supplied by the gripping force sensor with a fixed upper limit value, the comparison device providing a warning signal when the upper limit value is exceeded and an optical, acoustic or tactile warning device which can be activated by the warning signal.

This device can easily be installed in motor vehicles or driving simulators and thus make a significant contribution to increasing driving safety and preventing accidents. In order to also be able to recognize declining driver concentration or fatigue, it is provided in an expedient embodiment of the device according to the invention that the comparison device furthermore for comparing the output signal supplied by the gripping force sensor with a fixed lower limit value and for sending a warning signal if the determined gripping force is lower Falls below the limit, is formed.

Sensors of the dynamometer, capacitive, resistive or pneumatic type are particularly well suited as gripping force sensors, since they can easily be installed in control devices such as control sticks or steering wheels. It has proven to be advantageous if the gripping force sensor consists of a large number of individual sensor elements, the respective output signals of which are combined by a combination circuit, for example a summer or integrator, to form an overall output signal. The individual sensor elements are distributed along the gripping surface of the control device and thereby enable a significantly more precise detection and evaluation of the gripping forces.

An even finer evaluation of the gripping forces is made possible if sensor elements of the gripping force sensor are provided opposite one another on the top and the bottom of the control device, i.e. on the side facing the driver or facing away, and the signals of the upper and lower sensor elements are evaluated separately from one another. It has been shown that between the pressure exerted by the driver with the heel of the hand on the top of the control device and the pressure on the underside of the control device, which is caused by the fingers being closed around the control device or the "pulling in" the control device is exercised on the body, should be distinguished. The latter documents the driver's state of stress, while the former testifies to a confident and relaxed driving style.

The gripping forces determined by the gripping force sensor should be related to external parameters in order to refine the evaluation. This is preferably achieved by a device for dynamic adjustment of the upper and, if applicable, the lower limit of the gripping force as a function of the deflection of the control device or of external driving or simulation parameters, such as the vehicle speed, the steering angle and the condition of the road.

The deflection of the. Can further improve the evaluation result

Control device can be used as feedback information. For this purpose, the device for dynamic adjustment of the upper and lower is according to the invention Limit of the gripping force connected to a device for detecting the deflection of the control device.

As an alternative or in addition to this, in order to obtain further feedback information, it may be expedient to connect the device for dynamically setting the upper and lower limit values of the gripping force to at least one of an accelerometer, a distance meter or a braking force meter.

In a further embodiment of the invention, an automatic control system is provided which can be activated by the warning signal and which at least partially takes over control of the vehicle. This automatic control system can act on the brake system and / or the engine management of a vehicle. It can also be connected to at least one of an acceleration, a distance or a braking force sensor and process this information in a corresponding algorithm.

Particularly suitable for training purposes with debriefing by the instructor and learner driver is an embodiment of the device according to the invention, in which a video camera recording the driving or simulation course, in particular the behavior of the controlling person, and a storage device for storing the video data and the output signals of the gripping force sensor are also provided .

If the device according to the invention is used as a driving simulator, an image display device for generating a driving simulation state is advantageously provided for the controlling person. The simplest version can be a moving light bar that the test subject should follow. However, a more or less realistic street environment is more preferably displayed on a screen. The invention will now be described by way of example using preferred embodiments and with reference to the accompanying drawings. 1 schematically shows a basic embodiment of the invention, FIG. 2 schematically shows an expanded embodiment of the invention, FIG. 3 shows a block diagram of an embodiment according to the invention, FIG. 4 additional devices of the invention for a driving simulator, FIGS. 5 and 6 embodiments according to the invention the control device and FIGS. 7 and 8 pressure sensors for use in the control devices of FIGS. 5 and 6.

Referring first to FIG. 1, a first embodiment of the invention is shown schematically therein. It consists of a manually operable control device 1, (in the present case a steering wheel), a sensor 2 mounted on the control device 1 for measuring the force with which a driver grips the control device, the sensor 2 output signal F (t ) and a comparison device 3 for comparing the output signal F (t) supplied by the gripping force sensor with a fixed upper limit value Fmax, the comparison device 3 providing a warning signal W (t) when the upper limit value Fmax is exceeded. This warning signal W (t) activates an optical, acoustic or tactile warning device 4. The warning device 4 can comprise, for example, a lamp or a flashing light, a buzzer or a vibrating device, in particular a motor with an unbalance element. Optionally, the comparison device 3 evaluates the signal F (t) not only with regard to the upper limit value Fmax, but also with regard to a lower limit value Fmin. The axis of the control device 1 is further provided with a device 6 for detecting its angular deflection Φ (t) and is thus prepared for processing the deflection Φ (t). The device according to the invention can be used both in vehicles and in driving simulators.

2 shows an expanded embodiment of the invention. The control device 1 has sensors for measuring the gripping force on its upper side (reference number 20) and on the underside (reference number 2). As already explained above, is for the detection of driver excitation states mainly significant that compressive force that is exerted on the underside of the control device by clamping and pulling the control device towards the body. The pressure force exerted by the ball of the hand on the top of the control device, on the other hand, indicates more confident driving behavior. These two forces Fl (t) and F2 (t) can be selectively detected by the two sensors 2, 20 and fed to a comparison device 3, in which a comparison with an upper and a lower gripping force limit value Fmax, Fmin takes place. If at least the gripping force F1 (t) lies outside the bandwidth specified by Fmin and Fmax, a warning signal W (t) is generated and sent to the warning device 4, which is thereby activated. In addition to activating the warning device, the comparison device 3 is also connected to a control system 7 which, based on the signals or data from the comparison device, at least partially takes over control of the vehicle or driving simulator. When used in a vehicle, the control system 7 can act on the brake system 30 and / or the engine management 31 and / or the steering system 32.

In contrast to the first embodiment according to FIG. 1, in the embodiment of FIG. 2, for comparing the gripping force F (t) with the limit values Fmin and Fmax in the comparison device 3, no constant value is used for these limit values, but these limit values are used in one device 5 dynamically adapted as a function of driving parameters such as the vehicle speed v (t) or the deflection Φ (t) of the control device 1 (measured by means of the detection device 6) and passed to the comparison device 3. In this way, a significantly more precise evaluation of the relationship between gripping force and the driver's state of mind is made possible.

3 shows a block diagram of a further embodiment of the invention. The

Gripping force sensors consist of a large number of individual sensor elements (2-

1, 2-2, ... 2-n; 20-1, 20-2, ... 20-n) on the underside or the top of a control device (see above explanations of their function), their output signals are combined into two groups and are combined by a combination circuit (8-1, 8-2) for each group into group output signals F1 (t) and F2 (t), which are fed to the comparison device 3. Depending on the result of the evaluation, the comparison device 3 activates the warning device 4 and the control system 7. The limit values of the gripping force are in turn created dynamically in the device 5 and fed to the comparison circuit 3. The device 5 for dynamic setting of the limit values of the gripping force has a data input via which it receives the current speed values v (t) and, like the control system 7, is also provided with an acceleration sensor 10, a distance sensor 11 and a braking force sensor 12 connected. In addition, the device 5 is connected to a device 6 for detecting the deflection of the control device.

Fig. 4 shows additional devices when the invention is used in a driving simulator. The basic elements of the invention such as the comparison device and warning device are also present, but have been omitted from the drawing for reasons of clarity. In addition, they have already been described above, so that a further explanation can be omitted.

4 shows a video camera 1 3 recording the course of the driving or simulation or the behavior of the controlling person, which is connected to a storage device 14 for storing the video data. The storage device 14 also stores the output signals F (t) of the gripping force sensor 2 and the deflection Φ (t) of the control device. Furthermore, a computer 1 6 is provided which controls an image display device 1 5 (for example a light bar or a screen) in real time. The image display device 1 5 contains information which gives the controlling person instructions on where to steer. In the simplest case, this can be a wandering point of light that the person with the control device 1 should follow. However, it is preferably provided that realistic driving environments are imported via a screen in order to create a believable one Generate driving simulation state for the controlling person. Since when driving - especially in motorsport - the forces transmitted to the steering wheel represent an important source of information for the driver, it is further provided that the computer 16 controls an angular drive 18 according to the electrodynamic principle via a servo amplifier 17. Drives of this type are frictionless in the de-energized state and can be operated as a passive element (friction element) and active element (force or torque transmitter) via current injection. With this device, jerk-transmitted forces can be simulated well.

In FIGS. 5 and 6, two embodiments of a control device 1 adapted for the invention are shown in perspective and partially in an exploded view.

Fig. 5 shows a control device 1 in the form of an oval joystick, as used in carting. The control stick has a frame 22, on the top left and right of which two handle pieces 21 -1 and and 21 -2 are movably but captively mounted. Two force sensor elements 20-1 and 20-2 are each arranged between the upper handle pieces and the frame, which measure the force with which the upper handle pieces 21 -1 and 21 -2 are pressed against the frame 22. On the underside of the frame 22, two further handle pieces 23-1 and and 23-2 are movable but captively mounted on the left and right between the lower handle pieces and the frame, two force sensor elements 2-1 and 2-2 are each arranged, which measure the force , with which the lower handle pieces 23-1 and 23-2 are pressed against the frame 22.

6 shows a control device 1 in the form of a spoke steering wheel which has a circular steering ring 24, on the underside of which a force sensor element 2-1 is mounted between the steering ring and a plurality of finger pressure pieces 25. Capacitive, resistive, pneumatic sensors or sensors based on the electrodynamic principle are preferably used as force or pressure sensors.

The structure of a capacitive force sensor 2 'is shown schematically in FIG. 7. It consists of two capacitor plates 41, 42, between which an elastomer 45 is arranged as a dielectric. If the distance between the two capacitor plates is changed by an external force F, the capacitance of the capacitor changes. This can be measured by the circuit shown with an AC oscillator 43 and an amplifier 44. Each of the two capacitor plates 41, 42 consists, from the outside inwards, of a grounded shield made of conductive material, a non-conductive polyester film and an electrode layer made of highly conductive material.

Resistive force sensors are made of substances that change their resistance under pressure (e.g. a mixture of carbon and binder). On the other hand, strain gauges are used, the pressure acting from the outside leading to a change in their length and thus to a change in their resistance. The changes in resistance are also measured electrically.

8 shows a pneumatic force sensor. This has a compressible balloon 46, which is compressed by an external force F. The balloon 46 communicates via an air line 47 with an air reservoir 48. The air from this reservoir 48 can only flow into the balloon when its pressure is at least as great as the pressure acting on the balloon from the outside. Therefore, the pressure in the reservoir 48 is increased until air flows into the balloon 46. The pressure value measured at this moment in the reservoir by means of a manometer 49 corresponds to the pressure acting on the balloon from the outside.

Claims

Claims:

1 . Method for monitoring the ability to drive of a person controlling a vehicle or a driving simulator, the vehicle or the driving simulator having a manually operable control device (1), characterized by the steps: a) determining the gripping forces (F (t)) with which the person holds the control device (1), b) comparing the gripping forces with a defined upper limit value (Fmax), and c) sending out a warning signal (W (t)) if the determined gripping forces (F (t)) exceed the upper one Exceed limit value (Fmax).

2. The method according to claim 1, characterized by the further steps: d) comparing the gripping forces (F (t)) with a fixed lower limit value (Fmin), and e) sending out a warning signal (W (t)) if the determined gripping forces (F (t)) fall below the lower limit (Fmin).

3. The method according to claim 1 or 2, characterized by the further steps: f) determining an average value of the gripping forces (F (t)), and g) subtracting the average value of the gripping forces (F (t)) from their instantaneous value before Comparison of the gripping forces (F (t)) with the upper limit value (Fmax) or the lower limit value (Fmin).

4. The method according to any one of the preceding claims, characterized in that the upper limit value (Fmax) and possibly the lower limit value (Fmin) dynamically depending on the deflection (Φ (t)) of the control device (1) or external driving parameters, such as the vehicle speed (v (t)), the steering angle and the road surface.

5. The method according to any one of the preceding claims, characterized in that the emitted warning signal (W (t)) activates an optical, acoustic or tactile warning device.

6. The method according to any one of the preceding claims, characterized in that the warning signal emitted (W (t)) activates an automatic control system (7) which at least partially takes over control of the vehicle.

7. The method according to claim 6, characterized in that the automatic control system (7) brakes the vehicle or stops.

8. The method according to claim 6 or 7, characterized in that the automatic control system (7) reacts to signals from at least one of an acceleration (10), a distance (1 1), or a braking force sensor (12).

9. Device for monitoring the driving ability of a person controlling a vehicle or a driving simulator, the vehicle or the driving simulator having a manually operable control device (1), characterized by at least one sensor (2;) arranged on or in the control device (1). 20) for measuring the force with which the controlling person grips the control device, the at least one sensor (2; 20) delivering an output signal (F (t)) proportional to the gripping force, a comparison device (3) for comparing that of the gripping force sensor ( 2; 20) delivered output signal (F (t)) with a fixed upper limit value (Fmax), the comparison device (3) providing a warning signal (W (t)) and an optical, acoustic or when the upper limit value (Fmax) is exceeded tactile warning device (4) which can be activated by the warning signal (W (t)).

10. The device according to claim 9, characterized in that the comparison device (3) further for comparing the output signal from the gripping force sensor (2; 20) (F (t)) with a fixed lower limit value (Fmin) and for sending a warning signal (W (t)), when the determined gripping force falls below the lower limit value (Fmin).

1 1. Device according to claim 9 or 10, characterized in that the gripping force sensor (2; 20) is a sensor of the dynamometer, capacitive (2 '), resistive or pneumatic (2 ") type.

1 2. Device according to one of claims 9 to 1 1, characterized in that the gripping force sensor (2; 20) consists of a plurality of individual sensor elements (2-1 to 2-n; 20-1 to 20-n), their respective Output signals (F1 (t); F2 (t)) are combined by a combination circuit (8-1; 8-2), for example a summer or integrator, to form a total output signal.

1 3. Device according to one of claims 9 to 1 1, characterized in that the gripping force sensor (2; 20) sensor elements (2-1 to 2-n; 20-1 to 20-n) on the top and bottom of the control device has, which can be evaluated separately.

14. Device according to one of claims 9 to 1 3, further characterized by a device (5) for dynamic adjustment of the upper (Fmax) and optionally the lower (Fmin) limit value of the gripping force as a function of the deflection (Φ (t)) Control device (1) or external driving or simulation parameters, such as the vehicle speed (vt), the steering angle and the road surface.

1 5. Apparatus according to claim 14, characterized in that the device (5) for dynamic adjustment of the upper and lower limit of the gripping force with a Device (6) for detecting the deflection (Φ (t)) of the control device (1) is connected.

1 6. Apparatus according to claim 14 or 15, characterized in that the device (5) for dynamic adjustment of the upper and lower limit of

Gripping force is connected to at least one of an accelerometer (10), a distance meter (11) or a brake force meter (12).

1 7. Device according to one of claims 9 to 16, characterized in that further an automatic control system (7) is provided which can be activated by the warning signal and at least partially takes over control of the vehicle or driving simulator.

18. The apparatus according to claim 1 7, when related to a vehicle, characterized in that the automatic control system (7) acts on the brake system (30) and / or the engine management (31) and / or the steering system (32) of a vehicle.

19. The apparatus of claim 1 7 or 18, characterized in that the automatic control system (7) with at least one of an acceleration (10), a distance (1 1), or a braking force sensor (12) is connected.

20. Device according to one of claims 9 to 19, characterized in that further a video camera (13) recording the driving or simulation course, in particular the behavior of the controlling person, and a storage device (14) for storing the video data and the output signals of the gripping force sensor (2; 20) is provided.

21. Device according to one of claims 9 to 19, when related to a driving simulator, characterized in that an image display device (15) is provided for generating a driving simulation state for the controlling person.