Method and device for memorizing a new lateral position of a lane-keeping system for an autonomous vehicle

Abstract

The invention relates to a method and device for memorizing a new lateral position of a lane-keeping system for an autonomous vehicle, said system being activated, said method being implemented by a processor and comprising the steps of: Receiving (201) a lateral position, said position being a measurement of a lateral distance relative to a lane in which said vehicle is traveling; Receiving (202), from a driver monitoring system of said vehicle, an attention level indicator; Determining (203) a first threshold based on said attention level indicator; Receiving (204) a level of force applied to the steering wheel; Once the force level becomes greater (205) than said first threshold, determining and memorizing (209) said new lateral position when the force level subsequently becomes less than (208) a second threshold. Figure to be published for the abstract: Figure 2

Description

Title of the invention: Method and device for memorizing a new lateral position of a lane keeping system of an autonomous vehicle Technical field of the invention

[0001] The invention is in the field of autonomous vehicle driving assistance systems. In particular, the invention relates to a method and device for storing a new lateral position of a lane keeping system of an autonomous vehicle. State of the art

[0002] The term "vehicle" means any type of vehicle such as a motor vehicle, a moped, a motorcycle, a storage robot in a warehouse, etc. The term "autonomous driving" of an "autonomous vehicle" means any method capable of assisting the driving of the vehicle. The method may thus consist of partially or totally steering the vehicle or providing any type of assistance to a natural person driving the vehicle. The method thus covers all autonomous driving, from level 0 to level 5 in the OICA scale, for International Organization of Motor Vehicle Manufacturers.

[0003] Methods capable of assisting the driving of the vehicle are also called AD AS (acronym for "Advanced Driver Assistance Systems"), AD AS systems or driving assistance systems. The function known as lane position assistance, also known as LPA or LPA system (acronym for "Lane Positioning Assist") is a known AD AS function.

[0004] The LPA system identifies the boundaries of a traffic lane on which the vehicle is traveling. The LPA steers the vehicle within this lane to maintain it in a lateral position chosen by the driver. For this, the system uses a camera placed on the upper part of the windshield. The system is activated by pressing a dedicated button, the button being close to the driver of the vehicle.

[0005] Upon activation, the LPA system determines the lateral position chosen by the driver. This position is not necessarily the center of the lane. The lateral position is a lateral deviation between an origin of a reference point linked to the vehicle, for example the center of gravity, the middle of the front axis, ..., relative to one of the lane boundaries, left boundary and right boundary, along a lateral axis. The lateral axis is an axis perpendicular to a longitudinal axis such that a plane formed by the longitudinal axis and the lateral axis is parallel to a horizontal plane of the road. The longitudinal axis is parallel to a normal direction of travel of the vehicle. If the driver activates the LPA when the vehicle is ten centimeters, for example, from the right lane boundary, the LPA system will keep the vehicle 10 centimeters from the right lane boundary.

[0006] As soon as the LPA regulation is activated, a green pictogram is displayed on a display device. Said pictogram represents the left and right boundaries of the lane. Also, the regulation, by small actions on the steering, directs the vehicle and maintains it in the position chosen by the driver, in the traffic lane.

[0007] The driver must hold the steering wheel correctly. The driver must exert a torque on the steering wheel that is lower than a first predetermined threshold in order for the LPA system to perceive the movements of the steering wheel. At any time, by exerting a torque on the steering wheel that is higher than the first predetermined threshold, the driver can modify the position of the vehicle by acting on the steering wheel and define a new lateral position. The predetermined threshold depends on the vehicle (size, weight, etc.) and the speed of the vehicle. For example, this threshold, expressed as steering wheel torque, varies from 1 to 1.2 Nm. As soon as he considers that the position of the vehicle is suitable for him, while keeping his hands on the steering wheel, the driver must release the force, to let the system determine this new position. A released force corresponds approximately to -0.2 Nm relative to the predetermined threshold.However, for drivers who hold the steering wheel very rigidly (close to the first predetermined threshold), the system often determines new lateral positions causing involuntary decentering relative to the center of the lane or relative to the previous position desired by the driver. In addition, the level of the predetermined threshold is not known by the driver.

[0008] It has been found that a tired or distracted driver does not hold the steering wheel in the same way as when the driver is not tired or when the driver is paying attention to what is happening on the road. When tired, the driver has a "heavy" hand and holds the steering wheel rigidly. When distracted, the driver makes sporadic actions on the steering wheel. In both cases, the system often determines new lateral positions, causing involuntary off-centering. Summary of the invention

[0009] An object of the present invention is to remedy the aforementioned problem, in particular to avoid involuntary off-centering or shifting in the track.

[0010] To this end, a first aspect of the invention relates to a method for storing a new lateral position of a lane keeping system of an autonomous vehicle, said system being activated, said method being implemented by a processor and comprising the steps of: - Receiving a lateral position, said position being a measurement of a lateral distance from a traffic lane in which said vehicle is traveling; - Reception, from a monitoring system of a driver of said vehicle, of an attention level indicator; - Determination of a first threshold based on said attention level indicator; - Receiving a level of force applied to the steering wheel; - Once the level of effort becomes higher than the said first threshold, determine mination and memorization of said new lateral position when the level of effort then becomes lower than a second threshold.

[0011] Thus, the first threshold is adapted according to the level of attention. For a new lateral position to be memorized, a tired or distracted driver must apply a greater level of effort to the steering wheel than when the driver holds the steering wheel during the position regulation phase. The driver's level of fatigue or distraction is then taken into account to modify the first threshold and thus avoid involuntary off-centering.

[0012] Advantageously, the determination of said new lateral position is a function of a history of received lateral position values.

[0013] This avoids a new positioning based on an aberrant value.

[0014] Advantageously, the method further comprises a step of detecting a level of force greater than a third threshold, and a step of deactivating said lane keeping system when the level of force becomes greater than said third threshold.

[0015] Thus, by exerting significant effort on the steering wheel, the driver will deactivate the system if necessary, for example to change lanes, overtake another vehicle, etc.

[0016] Advantageously, said second threshold is determined as a function of said attention level indicator.

[0017] Thus, said second threshold will also be adapted according to the level of attention in order to have consistent behavior. If the driver holds the steering wheel rigidly, the different thresholds are adapted accordingly.

[0018] Advantageously, said third is determined as a function of said attention level indicator.

[0019] Thus, said third threshold will also be adapted according to the level of attention to have consistent behavior. If the driver holds the steering wheel rigidly, the different thresholds are adapted accordingly.

[0020] A second aspect of the invention relates to a device comprising the lane keeping system, the driver monitoring system, and a memory associated with at least one processor configured to implement the method according to the first aspect of the invention.

[0021] The invention also relates to a vehicle comprising the device.

[0022] The invention also relates to a computer program comprising instructions which, when the program is executed by the device according to the second aspect of the invention, lead the latter to implement the method according to the first aspect of the invention. Brief description of the figures

[0023] Other characteristics and advantages of the invention will emerge from the description of the non-limiting embodiments of the invention below, with reference to the appended figures, in which:

[0024] [Fig.l] schematically illustrates a device, according to a particular example of embodiment of the present invention.

[0025] [Fig.2] schematically illustrates a method for memorizing a new lateral position of a lane keeping system of an autonomous vehicle, according to a particular embodiment of the present invention. Detailed description of the invention

[0026] The invention is described below in its non-limiting application to the case of an autonomous motor vehicle traveling on a road or on a traffic lane. Other applications such as a robot in a storage warehouse or a motorcycle on a country road are also conceivable.

[0027] [Fig. 1] represents an example of a device 101 included in the vehicle, in a network (“cloud”) or in a server. This device 101 can be used as a centralized device in charge of at least certain steps of the method described below with reference to [Fig. 2]. In one embodiment, it corresponds to an autonomous driving computer.

[0028] In the present invention, the device 101 is included in the vehicle.

[0029] This device 101 can take the form of a box comprising circuits printed, any type of computer or even a smartphone).

[0030] The device 101 comprises a random access memory 102 for storing instructions for the implementation by a processor 103 of at least one step of the method as described above. The device also comprises a mass memory 104 for storing data intended to be retained after the implementation of the method.

[0031] The device 101 may further comprise a digital signal processor (DSP) 105. This DSP 105 receives data to format, demodulate and amplify, in a manner known per se, this data.

[0032] The device 101 also comprises an input interface 106 for receiving the data implemented by the method according to the invention and an output interface 107 for transmitting the data implemented by the method according to the invention.

[0033] For example, the input interface 106 can receive the following data: position or geographical location of the vehicle, speed and / or acceleration of the vehicle, set or predetermined positions / speeds / accelerations, engine speed, position and / or travel of the clutch, brake and / or acceleration pedal, detection of other vehicles or objects, position or geographical location of the other vehicles or objects detected, speed and / or acceleration of the other vehicles or objects detected, operating states of sensors, confidence index of data originating from or processed by sensors and / or devices similar to the device 101. For example, the sensors capable of providing data are: GPS associated or not with mapping, tachometers, accelerometers, RADAR, LIDAR, lasers, ultrasound, camera, a driver monitoring system, etc.

[0034] Driver monitoring systems are known and are capable of providing an indicator of the level of attention of a driver that the system is monitoring. Conventionally, these systems are called DMS (acronym for "Driver Monitoring Systems"). These systems can use image processing from a camera filming a driver's face to, for example, identify a period of blinking of the eyes, or any other information available in the vehicle (driving time, reaction time in relation to a command, etc.).For example, these levels may be a function of detection of a look away from the road for a consecutive duration of more than 3 s, detection of a look away from the road for a cumulative duration of more than 10 s over 30 s; detection of telephone use, a level of fatigue according to the KSS scale (acronym for Karolinska Spleepiness Scale), detection of eyes closed for less than 3 s, detection of eyes closed for more than 3 s, etc.

[0035] In an exemplary embodiment, the input interface receives a lateral position relative to a traffic lane in which the vehicle is traveling, an attention level indicator, a level of force applied to the steering wheel, a first, a second and a third predetermined threshold level of force applied to the steering wheel, ...

[0036] For example, the output interface 107 can transmit data similar to the data received by the input interface 106. The output interface 107 can transmit a new lateral position to be stored, a first, second and third determined thresholds, the result of a comparison test of a level of effort greater than or less than the first, second and third determined thresholds, a storage request order, a deactivation order, etc.

[0037] The memory 102 can record a history of the information received by the input interface 106 and a history of the information transmitted by the output interface 107.

[0038] [Fig-2] schematically illustrates a method of memorizing a new lateral position of a lane keeping system of an autonomous vehicle, according to a particular embodiment of the present invention.

[0039] The lane keeping system is activated. A lateral position is stored. The system regulates a lateral position of the vehicle relative to a left or right side of a lane on which the vehicle is traveling such that a lateral position of the vehicle converges towards the stored lateral position.

[0040] Step 201, RxPos, is a step of receiving a lateral position, said position being a measurement of a lateral distance relative to a traffic lane in which said vehicle is traveling. The lane keeping system is capable of measuring the lateral position of the vehicle. This measurement may also come from a system for perceiving the environment around the vehicle or from another AD AS system or device of the device 101 type.

[0041] Step 202, RXAtn, is a step of receiving, from a system for monitoring a driver of said vehicle, an attention level indicator. These driver monitoring systems are known. These systems are capable of providing an indicator of the driver's attention level. The indicator may be a multi-state indicator, such as a state corresponding to low attention, a state corresponding to average attention, and a state corresponding to high attention. The indicator may also be a percentage level of attention, with for example 0% signifying an absence of attention and 100% signifying absolute attention. The indicator may take other forms and / or values.

[0042] Step 203, DetSi, is a step of determining a first threshold as a function of said attention level indicator. This first threshold is called the memorization start threshold. This first threshold is used during step 205 described below. This first threshold makes it possible to determine whether the level of effort received in step 205 described below is greater than a first level, the first level being determined by the first threshold.

[0043] In lane keeping systems, only this first one is predetermined. The predetermined threshold depends on the vehicle (size, weight, etc.) and the vehicle speed. For example, this threshold, expressed as steering wheel torque, varies from 1 to 1.2 Nm. Other values ​​are possible. Other units are possible, for example, a level of force applied to the steering wheel can be a function of a rack displacement, a level of force on the rack, an angle of rotation of a tension bar placed on the steering column, etc.

[0044] In the present invention, the first threshold is a function of the driver's level of fatigue or attention. For example, the lower the level of attention, the higher the first determined threshold. In this example, it is assumed that the level of effort is a steering torque. If the level of attention corresponds to a high level of attention, respectively medium and low, the first threshold determined is of the order of 1 Nm, respectively 1.2 Nm and 1.4 Nm Advantageously, the first threshold determined is expressed in a unit corresponding to the level of force applied to the received steering wheel. In another example, in the presence of a medium attention level detected, the first threshold is of the order of 120% of the first threshold for a high attention level. When a low attention level is detected, the first threshold is of the order of 140% of the first threshold for a high attention level.

[0045] Advantageously, a second threshold is determined as a function of said attention level indicator. This second threshold is called the end of storage threshold. This second threshold is determined in a similar manner to the determination of the first threshold. However, the second threshold is determined such that the second threshold is less than or equal to the first threshold. In the example above, if the attention level corresponds to a high, medium and low attention level respectively, the second threshold determined is of the order of 0.8 Nm, respectively 1.0 Nm and 1.2 Nm. Other values ​​are possible. In another example, the second threshold for a high attention level, respectively for a medium and low attention level, is of the order of -20% of the first threshold value for a high attention level, respectively for a medium and low attention level.

[0046] Advantageously, a third threshold is determined as a function of said attention level indicator. This third threshold is called the threshold for stopping or deactivating the lane keeping system. This third threshold is determined in a similar manner to the determination of the first threshold. However, the third threshold is determined such that the third threshold is greater than the first threshold. In the example above, if the attention level corresponds to a high, medium and low attention level respectively, the third threshold determined is of the order of 2 Nm, respectively 2.4 Nm and 2.8 Nm. Other values ​​are possible. In another example, the third threshold for a high attention level, respectively for a medium and low attention level, is of the order of 200% of the first threshold value for a high attention level, respectively for a medium and low attention level.

[0047] Step 204, RxCvol, is a step of receiving a level of force applied to the steering wheel. Conventionally, the level of force corresponds to an absolute value of a steering wheel torque expressed in Nm. Advantageously, the level of force is obtained after it has undergone filtering techniques to avoid aberrant values. Other units are possible, for example, a level of force applied to the steering wheel can be a function of a displacement of the rack, a level of force on the rack, an angle of rotation of a tension bar placed on the steering column, etc. In an operating mode, the level of force can be signed, and in this case, the tests below are adapted accordingly as known to a person skilled in the art.

[0048] The level of effort on the steering wheel can be output by different systems, such as the LPA system, another AD AS system, an electronic steering assistance device, ...

[0049] Step 205, Cvol>Sl, is a test step if the effort level becomes greater than said first threshold. As long as the test is negative, we do not move on to step 206. Step 205 is carried out regularly, periodically or not, at least every millisecond to every second, preferably around 50 to 200 ms, but other values ​​are possible. When the test is positive, we begin a sequence of memorizing a new lateral position by moving on to step 206.

[0050] Step 206, Cvol>S3, is a step of detecting a level of force greater than a third threshold. Said third threshold may be predetermined or determined in step 203. As soon as the level of force is greater than this third threshold, we proceed to step 207. Step 207, Stp, is a step of deactivating said lane keeping system when the level of force becomes greater than said third threshold. By a significant level of force applied to the steering wheel, the driver shows his desire to take control of the steering of the vehicle, for example to change lanes, and therefore the lane keeping system must be deactivated.

[0051] Step 208, Cvol <S2, est une étape de test si le niveau d’effort devient inférieur audit deuxième seuil. Ledit deuxième seuil peut être prédéterminé ou déterminé à l’étape 203. Entre l’étape 205 et l’étape 208, en exerçant un niveau d’effort supérieur au premier seuil, le système LPA, laisse le conducteur modifier une trajectoire du véhicule. Cette modification de trajectoire est légère puisque le niveau d’effort est inférieur eu troisième seuil. Lorsque le niveau d’effort devient ensuite inférieur au deuxième seuil, on passe à l’étape 209.

[0052] Step 209, MemPos, is a step of determining and storing said new lateral position. By determining the second threshold as a function of the level of attention in a manner similar to the determination of the first threshold, the system becomes more coherent and understandable by the driver who holds the steering wheel rigidly. In addition, the third threshold is also adapted similarly to the determination of the first threshold. In the present invention and in the illustrated example, the relative difference between the first threshold and the second threshold and between the first threshold and the third threshold are made according to the level of attention, thus making a system adapted to the level of fatigue and attention of the driver.

[0053] Advantageously, the determination of said new lateral position is a function of a history of received lateral position values, thus allowing for smoother behavior.

[0054] The present invention is not limited to the embodiments described above as examples: it extends to other variants.

[0055] For example, the method has been described according to a sequence of steps. Certain steps can be carried out in parallel or according to another sequence.

[0056] Data is received by the device 101. The reception of this data is received regularly, periodically or not, at least every millisecond to every second, preferably around 50 to 200 ms, but other values ​​are possible.

[0057] Data are determined by the device 101. The determinations are made regularly, periodically or not, at least every millisecond to every second, preferably around 50 to 200 ms, but other values ​​are possible. These determinations can be made with all or part of the received data.

[0058] Tests have also been detailed. The invention is not limited to the form of these tests, and extends to any type of other form performing the same function (statistical tests, etc.).

Claims

Claims

1. Method for storing a new lateral position of a lane keeping system of an autonomous vehicle, said system being activated, said method being implemented by a processor (103) and comprising the steps of: - Receiving (201) a lateral position, said position being a measurement of a lateral distance from a traffic lane in which said vehicle is traveling; - Receiving (202), from a system for monitoring a driver of said vehicle, an attention level indicator; - Determining (203) a first threshold as a function of said attention level indicator; - Receiving (204) a level of force applied to the steering wheel; - Once the level of force becomes greater (205) than said first threshold, determining and storing (209) said new lateral position when the level of force then becomes lower (208) than a second threshold.

2. The method of claim 1, wherein the determination (209) of said new lateral position is a function of a history of received lateral position values.

3. Method according to one of the preceding claims, in which the method further comprises a step of detecting a level of force greater than a third threshold, and a step of deactivating (207) said lane keeping system when the level of force becomes greater than said third threshold.

4. A method according to any preceding claim, wherein said second threshold is determined (203) as a function of said attention level indicator.

5. Method according to one of claims 3 to 4, wherein said third threshold is determined (203) as a function of said attention level indicator.

6. Device (101) comprising the lane keeping system, the driver monitoring system, and a memory (102) associated with at least one processor (103) configured to implement the

7.

8. method according to one of the preceding claims. Vehicle comprising the device according to the preceding claim. Computer program comprising instructions which, when the program is executed by the device (101) according to claim 6, cause the latter to implement the method according to one of claims 1 to 5.

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