ES2317810A1 - Method and system for controlling driver activity in road vehicles (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Method and system to control the activity of the driver in road vehicles. The system comprises: - at least one sensor configured to measure the variation of the position of at least one driving control of the vehicle or the activation of said command; - means of issuing alerts installed in the vehicle itself; - a control unit with data processing means, configured to sample the values measured by the at least one sensor and from said values determine a level of activity of the driver in driving the vehicle and emit, through the means of issuance of alerts, an alert warning in case that said level of driver activity is lower than a minimum activity level nactmin during a time of activation of warning tactivaciºn. (Machine-translation by Google Translate, not legally binding)

Description

Method and system to control the activity of the Driver in road vehicles.

Field of the Invention

This invention is part of the sector of automobile and road transport vehicles, specifically within the field of methods and devices to help driver and, within these, those who serve to help the driver to maintain his alertness and prevent accidents due to tiredness or drowsiness.

Background of the invention

The fact of supervising that the driver is active corresponds to man-dead systems that have been installed in railway driving for weather. Although there are different systems that differ in implementation of some details, methods or modes of operation of these systems are based on a timer that returns to zero when the driver acts on the mechanism of reset-override and, otherwise, occurs alarm activation and emergency intervention (braking). Thus, train man-dead systems usually consist of a logical timer integrated in a circuit that activate the dead man, some actuators, some driver actuation mechanism to reset the timer or cancel the warnings and an action component on the train to Take it to a safe detection.

The most common way of implementing these train implanted systems consist of push buttons on which the driver must act according to different alternatives: keep the button pressed, press and release the button periodically or press when an alarm is activated. Sayings systems can be a driver nuisance or distraction which is not harmful in train driving because the machinist just have to maintain the proper speed to the track. Thus, the railway man-dead systems they make sense as soon as the driver has relatively few performances. on the train On road vehicles where the performance on the vehicle is constant (small rectifications of direction, curves, gear changes, acceleration and brake by different circumstances: traffic speed tracking, road layout, etc.), the relevance of a system of type of those found on railroads is unclear without a  It would be adaptation.

In the environment of road vehicles (cars, trucks, coaches), where attention on the road is crucial, the installation of a man-dead system based only on a timer that emits signals from time to time at which the Driver must answer. In fact, so far, in the sector These devices are not installed from the car.

Of course, maintain the degree of alertness and driver's attention of a vehicle is equal to or more important than In the case of a train. The number of accidents due to tiredness or sleepiness of the driver is very significant and is This is why there are many efforts in the direction of ensure the driver's attention on the task of driving.

Now, in general, efforts have been aimed at monitoring or monitoring the state of the driver in front of the solution to be proposed.

The mechanisms to monitor alertness of the driver are very empty and can be classified in the following types:

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Sensors that are placed on the driver to monitor his physiological state in general. Inside Of this type we find a great variety of options. By example, utility models: ES1048200-U, ES1060229-U or ES1024332-U collect different sensor alternatives to measure the inclination of the head; ES2003191 uses electromagnetic sensors to measure cardiac and cerebral activity. On the other hand, the European research project AWAKE collects an important effort in the development of sensors for monitoring Physiological driver and classification of his state of alert. The main feature of these systems is that they are invasive and can be annoying and therefore generate rejection in the driver

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Another group are sensors that are placed in the vehicle. The most common is to monitor the position of the steering wheel and the pedals, but there are also capacitive sensors for driver position, grip on the steering wheel, etc. Based on these measures, the driver's fatigue status is determined. Examples of this approach can be again the European AWAKE project or the patents ES2212888-A1, US4463347. In other patents we find similar ideas to determine the alert status: WO9616830 (measurement of response times), US507481 (position of the steering wheel and estimation of the situation of the vehicle through artificial vision), US5745031 (measurement of high frequency movement in the steering wheel ). There are also some research articles, for example, Sayed, R., & Eskandarian, A. (2001). "Unobtrusive drowsiness detection by neural network learning of driver steering. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 215 (9), 969-975", describes a system for determining the state of drowsiness through a network neuronal that works with steering wheel position data. The problem with all these systems is the variability of the driver characteristics. This is corroborated in the conclusions of the AWAKE project where a very similar content conclusion appears. In summary, it is not easy to determine the driver's alert status and, as of today, a completely reliable system has not been determined, given the variety of characteristics of the potential drivers.

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Methods by artificial vision. With this type of technology are very numerous efforts. We just want to highlight what the solution looks like today validated for driver surveillance, the measure called PERCLOS which consists in determining the percentage of time with the eyes closed. In any case, in all of them we find the usual problems of artificial vision: dependence on lighting, cases that cannot be monitored (for example, glasses of sun) and always a reliability that is not complete even in Laboratory controlled trials.

In all the above alternatives a significant effort in determining alertness and activating measures according to the state of the driver such as the warning or even intervention on the vehicle. Can be found patents or research seeking a pattern of behavior of the driver in the face of fatigue or drowsiness, although this Pattern is not perfectly clear.

In conclusion, the driver's alert status It is subject to external and internal driver parameters, it is not easy task your determination and even less find a rule universal that allows a safety performance. This will not be the approach of this invention and therefore the results and advantages that can be expected from the proposed method and device will be more realistic.

The invention to be described is not based on determine the alert status, but in checking that the Driver is active. It is not intended to check its speed either of reaction or any other parameter that serves to determine its attention or capacity. The usual driving activity is much more  easy to characterize and, within a range, is quite general.

In this sense, as already noted, this invention tries to adapt the railway systems of dead man around a road vehicle  taking into account the different degree of attention and actions of driving that requires one and the other, and raising the activity of driver as a measure for the cancellation of the warning system said dead man.

Description of the invention

The invention relates to a method for monitor driver activity in road vehicles of according to claim 1 and a system according to the claim 9. Preferred embodiments of the system and method They are defined in the dependent claims.

The method comprises:

- determine a level of driver activity in driving the vehicle checking the variation of the position of at least one driving command of the vehicle or the activation of said command;

- in case the activity level of the driver is less than a minimum activity level N_ {ACTMIN} during a warning activation time T_ {ACTIVATION}, issue a  alert notice.

The method preferably also includes step up the alert notice in case the driver during a warning intensification time T_ {INTENSIFICATION} determined since the alert was activated do not respond to same by activating means of cancellation of the notice of alert.

The activation of the means of cancellation of the Alert notice is done by any one of the following:

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an activity level of driver above the minimum activity level N_ {ACTMIN};

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driver performance on a specific sensor

Warning intensification time T_ {INTENSIFICATION} and warning activation time T_ {ACTIVATION} are preferably determined by the sum of three parameters: one determined by the user, another random and another speed dependent.

The determination of the activity level of the driver is performed over a T_ {WINDOW} time interval of sampling to be considered to sample the variation of the position of the at least one driving command or the activation of the same, and according to the result of said sampling.

The method may additionally comprise adjust periodically:

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warning activation time T_ {ACTIVATION};

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the intensification time of T_ {INTENSIFICATION} notice;

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the interval T_ {WINDOW} of sampling time.

In the event that a plurality of driving controls, the level of driver activity can be calculate using the weighted sum of the means of the value absolute of the finite first-order differences of the measures of position or condition of the driving controls sampled in the T_ {WINDOW} interval of sampling time.

An object of the present invention is also a system to control driver activity in vehicles road that includes:

- at least one sensor configured to measure the variation of the position of at least one driving control of the vehicle or activation of said command;

- means of issuing alerts installed in the own vehicle;

- a control unit with means of data processing, configured to sample values measured by the at least one sensor and from these values determine a level of driver activity in driving vehicle and issue, through the means of issuing alerts, a alert notice in case that said activity level of the driver is less than a minimum activity level N_ {ACTMIN} during a warning activation time T_ {ACTIVATION}.

The system also includes preferably:

- means of canceling the alert notice;

- means of issuing intensified alerts configured to intensify the alert notice in case the driver during a warning intensification time T_ {INTENSIFICATION} determined since the warning was activated alert does not respond to it by activating the means of Cancellation of the alert notice.

The means of canceling the alert notice preferably comprise a pressure sensor distributed over the steering wheel and constituted by a pressure sensitive fabric.

The at least one sensor used to measure the driver activity can be, among others, a turn sensor of the steering wheel or pressure sensors on the pedals.

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Description of a preferred embodiment of the invention

Unlike dead man systems conventional, the activation method of proposed dead-man introduces the activity of driver as an additional way to reset the timer or to cancel the action of the man-dead system. We consider that a driver is conducting active driving when you have to perform frequent actions on the different vehicle controls. In this way, the system would not disturb the driver while performing maneuvers, adjust speed, follow complicated paths or must face driving scenarios complexes that require your full attention.

In this sense it is understood that the driver acts on a driving control when you have to change your position significantly or activate it in some way. Be reasonably assumes that the driver is more active the more significant variations occur over the positions of said elements or more activations are caused. Therefore, it use the variation of the position of the driving controls or driving control activations to determine the driver activity through an index.

If the driver shows no type of activity on the driving controls for a certain time, Alert notices are issued that must be answered on the vehicle controls or the intended reset device.

According to the above, the method or mode of running dead-man who presents it can have, in a particular embodiment, the following stages:

one)

Activation time setting (T_ {ACTIVATION}) of dead-man warnings, Adjusting times of warning intensification and adjustment of the Time window for the calculation of the activity.

2)

He logical timer is set to zero.

3)

Measurement and sampling of parameters of driving.

4)

Calculation of driver activity according to the previous measures.

5)

If the activity is high or the driver has acted on the mechanism of reset-override, the logical timer returns to zero (returns to 2); otherwise it increases according to the time elapsed

6)

Yes, when the dead man warning activation time has passed, the driver does not act on the mechanism of reset-override or increase your activity level by driving circumstances, a notice is given to which a Attentive driver should answer.

7)

Yes, when the warning intensification time passes, the driver does not acts on the reset-override mechanism or your activity level rises, the warning intensifies to alert the driver of your inattention situation and optionally intervenes in the conduction to produce the controlled stop of the vehicle.

8)

Be return to 3.

It is assumed that the previous stages are running permanently and cyclically, according to a sampling time of the measured signals. The frequency of sampling may be low because the variations that are wanted Detect about the measurements are low frequency.

As you can see there are two times important in the method, the activation time T_ {ACTIVATION} which is the time between the last performance or level of high activity detected and the moment at which the driver notices; and another, the warning intensification time T_ {INTENSIFICATION}, which is the one between the moment in that the driver is notified and the warning is intensified and / or intervenes in the driving of the vehicle to produce its braking.

It is possible to manually adjust the timing of T_ {ACTIVATION} activation and T_ {INTENSIFICATION} intensification of notices. Always keeping in mind that they are two variables criticisms of the method, because very short times can cause a warning overload and therefore tiredness, distractions or system rejection, and too long a time can subtract Efficiency to the device.

The definitive adjustment of the warning times and notice intensification is done through the sum of three quantities, a first manual, adjusted by the user, another randomized, generated by the device that implements the method, to prevent the driver's performance from being rhythmic and one last speed dependent to increase times when the Speed is low.

On the other hand, it is noted that the intervention on driving through the corresponding braking is optional inside the device

The activity index cannot be a value instantaneous because the driving activity is produced by performances that are not punctual. Therefore, to obtain the index of activity it is necessary to determine a time window on the that this index is going to be calculated.

How the activity index is going to be calculated through a window of values that is updated to the rhythm of the sampling time (T_ {SAMPLING}), the values of the measurements are stored in matrix form so that, in each cycle, the new value of each measure replaces the oldest value. This means that the calculation is performed over a time interval of T_ {WINDOW} seconds that extends in each moment between the current instant and T_ {WINDOW} seconds before that instant current, that is, (T_ {CURRENT} - T_ {WINDOW}, T_ {CURRENT}). How interested in the variation in the measures and not the measure itself nor the sign of the variation, when you have all the values of the measurements the finite first order differences of the values of the measures, the absolute values are found, they are added all absolute values and the average for the position or status of each command; finally a weighted sum of the means of the positions or states of the controls to find the definitive activity index.

Since the variations that interest us correspond to a significant driver activity (curves, gear changes, significant acceleration or braking) and not small adjustments on the steering wheel position or on the position of the accelerator that are not indicative of high activity is it is necessary to use a certain threshold on the amount obtained to distinguish moments of truly active driving.

Also, the window or interval of Time to calculate finite differences. If the interval, will enter into the calculation performances of the driver very previous in time and if the previous actions are shortened  will discard shortly after made. This interval is adjusted manually to the route or characteristics of the road and the driver. For very winding roads times may be enough short, while, for winding roads, but not continued may be better longer time intervals.

For example, the measures are considered for a first driving command M_ {1} and for a second driving of conduction M_ {2} for different moments t_ {1}, t_ {2}, t_ {3}, t_ {4} in an interval or window T_ {WINDOW} of time Of sampling,

one

Said measures M_ {1} and M_ {2} can be, by example, the specific position of the steering wheel and throttle, respectively. The value that will be obtained will depend on the type of used and conversion sensor analog-digital performed, but you can always convert to another magnitude or to the appropriate scale by a factor of suitable conversion (K_ {M2}, K_ {M2}): so K_ {Mi} will be the conversion factor for measurements made on the position of the M_ {i} command. In this way, measures of different controls that are quantitatively similar.

In the case of measures of the activation / deactivation of a driving control, such as for example the activation of the turn signals, you can define a value for each activation state. So for example for those driving controls that have only two positions, on and off, for example, 0 can be considered for the off value and 1 for the ignition value. In the case of flashers, -1 could be considered for the case of the left turn signal activated, 0 in case no flasher is activated, and 1 in the case of the right turn signal activated. Could also consider as two independent controls: the right turn signal and the left turn signal, with only two values: 0 when the corresponding flashing is off and 1 when activated. There are therefore multiple embodiments.

The differences are calculated below. finite first-order measures values, for each driving command:

2

The absolute values are then found:

3

All the absolute values are added:

4

For each command (M_ {1}, M_ {2}) it is contemplated the option to multiply the result of any previous stage by a factor P (P_ {M1}, P_ {M2}) so that more can be given relevance to the performance of one command or another.

The average for the position or state of each command, dividing the previous sum by the number of calculated differences, in this case 3:

5

Finally a weighted sum of the means of the positions or states of the controls to find the definitive activity level N_ {ACT}.

Level of \ activity \ N_ {ACT} = (3.33 + 5.33) / 2 = 4.33

In case there was a driving command M_ {3} that had only two positions, on and off, the Sampled values could be, by way of example:

6

The differences would be:

7

The absolute values would be:

8

The sum of all absolute values would:

9

The average would be:

10

At any point in the process you could multiply by a conversion factor P_ {M3} to adapt the values to the other controls M_ {1} and M_ {2}, in case The range of values is completely different. This value of M_ {3} obtained would be the level of activity related to said command M_ {3}.

Therefore, as explained there are different ways of calculating the activity level N_ {ACT}. The important in any case is that the position or state of each driving command (M_ {1}, M_ {2}) at different times of time (t_ {1}, t_ {2}, t_ {3}) within a range of T_ {WINDOW} sampling, and differences in value are calculated absolute of the sampled values between consecutive times (t_2 -t_ {1}, t_3 -t_ {2}, t_ {4} -t_ {3}), obtaining for each command the average of these values, the result being an indicative value of level of activity with respect to said command. Finally you get the level of driver activity as the average of the levels of activity for each command. As explained above, there may be different conversion parameters (K) or importance (P) to reach the final activity level value N_ {ACT}. If this value is less than a minimum activity level default, N_ {ACT} <N_ {ACTMIN}, in that range of T_ {WINDOW} sampling is considered that the driver is not sufficiently active and an alert is issued.

The man-dead system that implements the above method consists, in one embodiment particular, of the following elements:

one)

A microcontroller where the operating method is programmed previously described.

2)

A Timer reset mechanism or warning cancellation comfortable enough for the driver not to disturb Your driving task.

3)

A series of sensors to measure driving parameters.

4)

Some advertisers

5)

He wiring between all the elements and the microcontroller.

6)

Y, optionally, a mechanism of action on the vehicle for Take it to a safe detection.

The electronic microcontroller acquires all the signals, processes them and executes the warnings. As main part of it, the routine that implements the function of timer This can be reset by detecting activity by the driver or by his response in the reset-override system.

The mechanism of reset-cancellation of the dead man must comply that the driver's performance on him is comfortable, does not cause distraction or requiring the release of the steering wheel. To do this, you can use a pressure gauge distributed throughout the steering wheel by covering the steering wheel using a sensitive fabric at pressure (pressure-sensitive fabric or smart fabric) on which one acts by pressing hard on any flywheel point for a short time, and it interprets as a performance on it a pressure increase over any point on the steering wheel, that is, a pulse on the value of the measured pressure This change in the signal is easily identifiable and it is very simple for the driver to perform this action and, therefore, reset the timer and cancel the warnings. This solution is distinguished from other dead-man in existing railways where push buttons are arranged in Concrete positions, which may not be comfortable for the driver. In this way, it is not necessary to release the steering wheel or change the hand position to act on the device.

On the other hand, it is necessary to establish which will be the driving parameters chosen. Since the actions The driver's most common are the performances on the steering wheel and on the pedals, the position measurement of these elements of the automobile are the set of measures chosen with preference for Calculate the driver activity index. To do this, it have, if the vehicle does not have them, a steering wheel turn sensor and potentiometric sensors that determine the position of the pedals

In current vehicles it is possible to find data from different sensors that may be useful for the activity calculation, and, if the measures of said sensors from the data bus, this alternative is Preferable to any other for the simplicity of wiring. In case Otherwise, the new sensors must be installed and wired directly to the microcontroller, which, however, provides a versatile solution, installable in any vehicle without Need to know your internal electronic configuration.

As far as the warning to the driver is sought use a warning for the driver to react in case has misled or forgot to act on the mechanism of cancellation and, at the same time, that is not annoying so that the user does not  Store to disconnect the system. In this sense, the realization proposal is a small warning light on the dashboard, on the rearview mirror or at some other peripheral point in the field of driver's vision, so as not to cause distraction, but clearly perceive and, therefore, provoke the performance of the driver. If the driver's performance still does not occur, employs an additional alarm, this time more intrusive, in order to unambiguously warn the driver that his acting or to cause him to wake up or remain alert. Is That is why an acoustic alarm is the most appropriate and can be use the vehicle radio or buzzer for this purpose dedicated.

Finally, the optional vehicle stop it would be produced by sending the appropriate setpoint signals to the engine and to the brake system.

Claims (14)

1. Method for controlling driver activity in road vehicles, characterized in that it comprises: - determine a level of driver activity in driving the vehicle checking the variation of the position of at least one driving command of the vehicle or the activation of said command; - in case the activity level of the driver is less than a minimum activity level N_ {ACTMIN} during a warning activation time T_ {ACTIVATION}, issue An alert notice. 2. Method to control driver activity in road vehicles; according to claim 1, characterized in that it additionally comprises intensifying the alert notice in case the driver during a warning intensification time T_ {INTENSIFICATION} determined since the alert warning was activated does not respond to it by activating means of Cancellation of the alert notice. 3. Method for controlling the activity of the driver in road vehicles according to claim 2, characterized in that the activation of the means of cancellation of the alert is performed by:

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an activity level of driver above the minimum activity level N_ {ACTMIN}; I

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driver performance on a specific sensor

4. Method for controlling the activity of the driver in road vehicles according to any of claims 2-3, characterized in that the warning intensification time T_ {INTENSIFICATION} is determined by the sum of three parameters: one determined by the user, another random and other speed dependent. 5. Method for controlling driver activity in road vehicles according to any of the preceding claims, characterized in that the warning activation time T_ {ACTIVATION} is determined by the sum of three parameters: one determined by the user, another random and another speed dependent. Method for controlling the activity of the driver in road vehicles according to any of the preceding claims, characterized in that the determination of the level of driver activity is performed over a T_ {WINDOW} interval of sampling time to be considered for sampling. the variation of the position of the at least one driving control or its activation, and according to the result of said sampling. 7. Method for controlling the activity of the driver in road vehicles according to claim 6 when it depends on the 2, characterized in that it further comprises adjusting periodically:

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warning activation time T_ {ACTIVATION};

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the intensification time of T_ {INTENSIFICATION} notice;

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the interval T_ {WINDOW} of sampling time.

8. Method for controlling the activity of the driver in road vehicles according to any of claims 6-7, wherein a plurality of driving controls are sampled, characterized in that the level of driver activity is calculated by the weighted sum of the means of the absolute value of the first order finite differences of the position or status measurements of the driving controls sampled in the interval T_ {WINDOW} of sampling time. 9. System to control driver activity in road vehicles, characterized in that it comprises: - at least one sensor configured to measure the variation of the position of at least one driving control of the vehicle or activation of said command; - means of issuing alerts installed in the own vehicle; - a control unit with means of data processing, configured to sample values measured by the at least one sensor and from these values determine a level of driver activity in driving vehicle and issue, through the means of issuing alerts, a alert notice in case that said activity level of the driver is less than a minimum activity level N_ {ACTMIN} during a warning activation time T_ {ACTIVATION}. 10. System for controlling driver activity in road vehicles according to claim 9, characterized in that it additionally comprises: - means of canceling the alert notice; - means of issuing intensified alerts configured to intensify the alert notice in case the driver during a warning intensification time T_ {INTENSIFICATION} determined since the warning was activated alert does not respond to it by activating the means of Cancellation of the alert notice. A system for controlling the activity of the driver in road vehicles according to claim 10, characterized in that the means for canceling the warning notice comprises a pressure sensor distributed on the steering wheel and constituted by a pressure sensitive fabric. 12. System for controlling the activity of the driver in road vehicles according to any of claims 9-11, characterized in that the at least one sensor used to measure the activity of the driver is chosen from among the following: - steering wheel rotation sensor; - pressure sensors on the pedals. 13. System for controlling the activity of the driver in road vehicles according to any of claims 9-12, characterized in that the determination of the level of driver activity is performed over a T_ {WINDOW} interval of sampling time to be considered to sample the variation of the position of the at least one driving command or its activation, and according to the result of said sampling. 14. System for controlling the activity of the driver in road vehicles according to claim 13, wherein a plurality of driving controls are sampled, characterized in that the level of driver activity is calculated by the weighted sum of the means of the absolute value of the finite first order differences of the position or status measurements of the driving controls sampled in the T_ {WINDOW} interval of sampling time.