Method for automatically defining a maximum authorised speed

Abstract

The invention relates to a method for automatically defining a maximum authorised speed of a motor vehicle, the vehicle being provided with a means for perceiving the environment of the motor vehicle and a means for geolocating the motor vehicle, which method comprises: - a first step of detecting a new speed limit via the perceiving means of the vehicle; - a second step of determining a location of the motor vehicle close to an exit lane of the road via the geolocation means; - a third step of validating a route chosen by the motor vehicle on the exit lane or off the exit lane; then - a fourth step of transmitting the new speed limit to a human-machine interface of the vehicle and / or to an autonomous driving system of the motor vehicle.

Description

Description Title of the invention: Method for automatically defining a maximum authorized speed.

[0001] The invention relates to a method for automatically defining a maximum authorized speed. The invention further relates to a device for automatically defining a maximum authorized speed. The invention also relates to a computer program implementing the mentioned method. The invention finally relates to a recording medium on which such a program is recorded.

[0002] Automatic speed control systems are commonly installed on current vehicles.

[0003] These systems require, in particular, the determination of a maximum authorized speed based on information from several sources. However, in certain driving situations, the information received by the system for automatically defining a maximum authorized speed may be ambiguous or contradictory.

[0004] The aim of the invention is to provide a device and a method for automatically defining a maximum authorized speed which overcomes the above drawbacks and improves the devices and methods for automatically defining a maximum authorized speed known from the prior art. In particular, the invention makes it possible to produce a device and a method which are simple and reliable and which allow a reliable determination of a maximum authorized speed, in particular near an exit lane of a road.

[0005] To this end, the invention relates to a method for automatically defining a maximum authorized speed of a motor vehicle traveling on a road, the vehicle being equipped with a means for perceiving the environment of the motor vehicle and a means for geolocating the motor vehicle on a map comprising: - a first step of detecting a new speed limit by the vehicle's perception means; - a second step of determining the location of the motor vehicle near an exit lane from the road using the geolocation means; - if the second step has determined that the vehicle is close to an exit lane, a third step of validation of a route chosen by the motor vehicle on the exit lane or not; then - if the third step has validated that the route chosen by the motor vehicle takes the exit lane, a fourth step of transmission of said new speed limit to a human-machine interface of the vehicle and / or to a system of autonomous driving of the motor vehicle.

[0006] In one embodiment, the third validation step includes a time delay.

[0007] In one embodiment, the motor vehicle comprises direction indicators, and a yaw rate sensor, and the third validation step comprises: - detection of use of a direction indicator by a driver of the motor vehicle), and / or - detection, by means of the perception means, of a crossing of a separation line of the exit lane, and / or - detection of a crossing of a minimum threshold by a yaw rate of the motor vehicle measured by the yaw rate sensor and / or - location of the motor vehicle on the exit lane or not by means of geolocation.

[0008] In one embodiment, the motor vehicle travels on a first road comprising at least one traffic lane and an exit lane located in front of the motor vehicle, and the second step comprises a determination by the geolocation means of a given position of the exit lane, and a definition of a given section of the first road framing the given position.

[0009] In one embodiment, a maximum authorized speed applicable on a lane of the given section of the first road is greater than a minimum speed threshold, for example greater than 70 km / h, and / or the exit lane is tangent to a lane of the first road over a given length greater than a minimum length threshold.

[0010] In one embodiment, the given segment extends between a start position and an end position framing the first position, - the start position being defined by a first duration of travel by the motor vehicle of a distance between the start position and the first position, for example a duration of between one second and three seconds, and / or - the end position being defined by a second travel time of a distance between the first position and the end position, for example a time between one second and three seconds.

[0011] The invention further relates to a device for automatically defining a maximum authorized speed of a motor vehicle equipped with a means for perceiving the environment of the motor vehicle and a means for geolocating the motor vehicle on a map, the device comprising hardware and / or software elements implementing the method according to the invention.

[0012] The invention further relates to a computer program product comprising program code instructions recorded on a computer-readable medium for implementing the steps of the method according to the invention.

[0013] The invention also relates to a data recording medium, readable by a computer, on which is recorded a computer program comprising program code instructions for implementing the method according to the invention.

[0014] The invention also relates to a signal of a data carrier, carrying the computer program product according to the invention.

[0015] The attached drawings represent, by way of example, an embodiment of a definition device according to the invention and an embodiment of a definition method according to the invention.

[0016] [Fig.1] represents an embodiment of a motor vehicle implementing a method for automatically defining a maximum authorized speed.

[0017] [Fig.2] shows a road configuration in which the process of automatically defining a maximum authorized speed is implemented.

[0018] [Fig. 3] illustrates a situation in which the motor vehicle 100 is wrongly located on an exit lane by a geolocation means.

[0019] [Fig.4] illustrates a first situation in which the meaning of a speed limit sign is ambiguous.

[0020] [Fig.5] illustrates a second situation in which the meaning of a speed limit sign is ambiguous.

[0021] [Fig.6] is a flowchart of a method of executing a process for automatically defining a maximum authorized speed.

[0022] The motor vehicle 100 may be a motor vehicle of any type, including a passenger vehicle, a utility vehicle, a truck, or a public transportation vehicle such as a bus or shuttle.

[0023] An embodiment of a motor vehicle 100 according to the invention is described below with reference to [Fig.l].

[0024] In the remainder of the document, the term “maximum authorized speed” is used to designate the longitudinal speed limit applicable at the current time by the motor vehicle 100, taking into account the highway code, the traffic lane on which it is located and the speed limit signs relating to the road and / or the traffic lane on which it is located. The term “speed limit” can also be used to designate a “maximum authorized speed”.

[0025] An example of a road configuration requiring the implementation of the invention is represented by [Fig.2].

[0026] It is assumed that the motor vehicle 100 is traveling on a first road 200 comprising one or more traffic lanes 201, 202, 203 in the same direction. The first road 200 further comprises an exit 210 located in front of the vehicle au- In the rest of the document, the first route 200 is called “route 200”.

[0027] In the embodiment described, the motor vehicle 100 mainly comprises a system for defining a maximum authorized speed 10, an autonomous driving system 20, and a human-machine interface 30 allowing a display of a maximum authorized speed.

[0028] The autonomous driving system 20 makes it possible to automate the longitudinal movement of the motor vehicle 100. Advantageously, the autonomous driving system 20 limits the longitudinal speed of the motor vehicle 100 as a function of a maximum authorized speed which is transmitted to it by the system for automatically defining a maximum authorized speed.

[0029] Definition System 10 includes the following elements: - a means of geolocation 1 of the motor vehicle 100 on a map, - a means of perception 2 of the environment of the motor vehicle 100, - 3 direction change indicators, - a longitudinal speed sensor 4, - a yaw rate sensor 5, - and a calculation unit 6 comprising a microprocessor 61, an electronic memory 62 and communication interfaces 63 allowing the microprocessor 61 to communicate with the geolocation means 1, the perception means 2, the direction change indicators 3, the longitudinal speed sensor 4, the yaw rate sensor 5, the autonomous driving system 20 and the human-machine interface 30.

[0030] In one embodiment, the geolocation means 1 comprises a GPS location of the motor vehicle 100 on a standard definition map 11, or SD card. In the map 11, the road network is digitized in the form of databases containing the roads and information associated with the roads such as speed limits.

[0031] The accuracy of the geolocation means 1 is determined by the accuracy of the GPS location which is of the order of a few meters, for example it is between 3 and 5 meters or between 1 and 10 meters.

[0032] In the remainder of the document, the data collected by the geolocation system 1 and relating to the motor vehicle 100 are called “DI geolocation data”, or “DI data”.

[0033] The DI geolocation data includes a location of the motor vehicle 100 in an absolute orthonormal reference frame.

[0034] The geolocation means 1 also makes it possible to locate the motor vehicle 100 on a traffic lane 201, 202, 203 of a road 200. The geolocation data DI thus comprises a road identifier and / or a lane identifier. on which the motor vehicle 100 is located.

[0035] In one embodiment, the geolocation data DI comprises a curvilinear abscissa of the position of the motor vehicle 100 on the road 200. In the remainder of the description, only a single direction of travel SI of the road 200 is considered. The curvilinear abscissas are measured from a start of the road 200, the curvilinear abscissa increasing in the direction of travel SI. Other types of markers could be used to describe the invention.

[0036] The DI geolocation data also includes an identifier of the traffic lane of the motor vehicle 100.

[0037] The geolocation data DI further comprises a first maximum authorized speed VMA1, derived from the geolocation of the motor vehicle 100 on the SD card. The first maximum authorized speed VMA1 is determined by identifying the road 200 on which the motor vehicle 100 is traveling. The current curvilinear abscissa of the vehicle is also taken into account to determine the first maximum authorized speed VMA1. In one embodiment, the identifier of the traffic lane could also be taken into account for determining the first maximum authorized speed VMA1.

[0038] As a note, geolocation method 1 does not require the use of high-definition mapping.

[0039] The accuracy of the location means 1 may fluctuate, and the location of the motor vehicle 100 may be temporarily altered. Thus, in the situation illustrated by [Fig. 3], the motor vehicle 100 is detected by the GPS as traveling at the boundary between a lane 402 continuing straight ahead and a lane 403 turning to the right. The positions reported by the GPS are materialized by circles and form a reported trajectory 404. The positions interpreted by the geolocation means 1, from the positions reported by the GPS, are materialized by triangles and form an interpreted trajectory 405.

[0040] [Fig. 3] illustrates a situation where, on a portion of the interpreted trajectory 405 located in an exit zone 401, the geolocation means positions the motor vehicle 100 on the exit lane 403, while the vehicle is moving on the lane 402 continuing straight ahead.

[0041] When the traffic lane 402 and the exit lane 403 separate, the geolocation means readjusts the interpreted trajectory 405 to make it consistent with the positions reported by the GPS beyond the exit zone 401.

[0042] In this situation, the erroneous positioning of the motor vehicle 100 on the exit lane is likely to distort the value of the maximum authorized speed automatically associated with the motor vehicle 100 by the geolocation means 1. Indeed, in the example described by [Fig.3], when the vehicle crosses the zone 401, the geolocation means 1 identifies the maximum authorized speed as being that of the exit lane 403 and not that of the lane actually taken by the motor vehicle 100, which is lane 402 continuing straight ahead.

[0043] The geolocation means 1 also makes it possible to detect an exit lane 210 located on the road 200, upstream of the position of the motor vehicle 100. One embodiment of the detection of an exit lane is illustrated by [Fig.2].

[0044] The geolocation means 1 detects the exits located within a given distance horizon 223. Alternatively, the geolocation means 1 can detect the exits located within a given time horizon 224.

[0045] For example, in [Fig.2], at a given time t, the motor vehicle 100 is located at the curvilinear abscissa POS_V(t), and the geolocation means 1 detects the exit 210 as being located at the curvilinear abscissa POS_S, the curvilinear abscissas POS_V(t) and POS_S being separated from each other by a distance less than or equal to the given distance horizon 223; alternatively, the positions POS_V(t) and POS_S are separated from each other by a duration less than or equal to the given time horizon 224.

[0046] The position POS_S of output 210 is determined from the information contained in the SD card.

[0047] The accuracy of the GPS does not allow us to know whether the position POS_S determined by the geolocation system 1 corresponds to the curvilinear abscissa of the start of exit lane 210 or to a curvilinear abscissa located after the start of the exit, in a middle zone of exit 210.

[0048] Preferably, the position POS_S is located in the first half of the output channel 210.

[0049] The DI geolocation data contains the POS_S position.

[0050] In one embodiment, the perception means 2 comprises a camera, in particular a front camera, making it possible to locate the motor vehicle 100 relative to the elements of the driving scene with a precision of the order of a centimeter, or of around ten centimeters or a few tens of centimeters.

[0051] The data from perception means 2 are called “D2 perception data” or “D2 data”.

[0052] In the remainder of the document, the perception means 2 may also be referred to as camera 2. The camera 2 is capable of detecting and analyzing traffic signs located within the range of the camera 2. The analysis of the traffic signs may be carried out by image recognition means, for example of the neural network type.

[0053] The D2 perception data can thus contain the maximum authorized speed VMA2 resulting from an analysis of the images perceived by camera 2. In the rest of the document, the maximum authorized speed entered in the D2 perception data is called “second maximum authorized speed VMA2”.

[0054] The detection means 2 also makes it possible to detect a crossing of a white line, in particular a crossing of a separation line 211 between a lower speed lane 201 of the road 200, and an exit lane 210.

[0055] The detection means 2 further comprises a means for analyzing the relevance of the traffic signs relative to the motor vehicle 100. For example, if the camera 2 detects a speed limit sign associated with an arrow indicating that the sign concerns an upcoming exit lane, and if the camera 2 detects a crossing by the motor vehicle 2 of an entry line on the exit lane 210, then the speed limit sign is determined to be relevant for the motor vehicle 100.

[0056] Thus, the perception data D2 may contain a relevance index IP relating to the second maximum authorized speed VMA2. In one embodiment, the relevance index IP is a boolean taking the state “TRUE” when the second maximum authorized speed VMA2 is analyzed as relevant by the perception system 2; otherwise the relevance index IP is in the state “FALSE”.

[0057] However, the analysis of the relevance of a traffic sign presents numerous pitfalls. In particular, Figures 4 and 5 respectively present a first and a second situation in which the relevance of a traffic sign is problematic, in particular because no so-called "exit" arrow appears under the traffic sign to indicate that the traffic sign only concerns an upcoming exit lane.

[0058] The first situation, described in [Fig. 4], concerns a speed limit sign 401 relating to the rightmost lane 402. Since no arrow appears under the sign 401, camera 2 categorizes the sign 401 as relevant for all lanes, and therefore relevant for the motor vehicle traveling on the leftmost lane 403 and not affected by the sign 401.

[0059] [Fig.5] illustrates a second situation in which a speed limit sign 501 without an exit arrow is placed well upstream of an exit 501, and will therefore be interpreted by camera 2 as relevant to a motor vehicle, regardless of the lane it takes.

[0060] In addition, the definition system 10 comprises a lane change indicator 4, or turn signal 4. The definition system 10 has access to information according to which the driver has activated the turn signal 4. This information can advantageously be combined with other information from the camera 2 (in particular the lane on which the vehicle is located) to determine that the driver is leaving his traffic lane 201 to take the exit lane 210.

[0061] In one embodiment, the microprocessor 61 makes it possible to execute software comprising the following modules, which collaborate with each other: - a module 611 for detecting a new speed limit LV1 which collaborates with the vehicle's perception means 2, - a module 612 for determining whether the vehicle is located near an exit lane which collaborates with the geolocation means 1, the camera 2, and the longitudinal speed sensor 4, - a module 613 validation step of the route chosen by the vehicle, on the exit lane or not, which collaborates with the geolocation means 1, the camera 2, the direction change indicators 3, and the yaw rate sensor 5, - a module 614 for transmitting the new LV1 speed limit which collaborates with the autonomous driving system of the vehicle 20 and with the human-machine interface 30.

[0062] The motor vehicle 100, in particular the system 10 for automatically defining a maximum authorized speed, preferably comprises all the hardware and / or software elements configured so as to implement the method defined in the subject of the invention or the method described below.

[0063] A mode of execution of the definition method is described below with reference to [Fig.6]. The method comprises four steps E1, E2, E3 and E4 which are executed successively. Alternatively, steps E1 and E2 can be executed in parallel.

[0064] In the first step El, a new speed limitation VMA_1 is detected, coming from perception means 2.

[0065] In the second step E2, it is determined whether the motor vehicle 100 is located near an exit lane 210. For this, a first position POS_S of an exit lane 210 located in front of the motor vehicle 100 is determined, and a given section 220 of the first road 200 is defined, the given section 220 framing the first position POS_S.

[0066] The determination of a first position POS_S of the exit lane 210 is carried out by the geolocation means 1.

[0067] In a first sub-step E21 of step E2, geolocation data DI are received containing an indication of a position POS_S of an exit lane 210 located on the road 200 upstream of a current position POS_V(t) of the motor vehicle 100. In the embodiment described, the positions POS_S and POS_V(t) are curvilinear abscissae.

[0068] In an advantageous embodiment, step E2 further comprises a sub-step E22 of selecting the first output 210, according to the following criteria: - a maximum authorized speed V_max_aut on a lane 201, 202, 203 of the given section 220 of the first road 200 is greater than a minimum speed threshold LIM_min, for example greater than 70 km / h, and / or - exit lane 210 is tangent to lane 201 of the first road 200 on a given length L_tan greater than a minimum length threshold L_min. In one embodiment, the minimum length threshold L_min is between 60 and 140 meters, preferably 100 meters.

[0069] In other words, according to a first eligibility criterion of exit 210, the definition method according to the invention is intended for situations where a speed limit applicable to an exit lane is significantly lower than the speed limit applicable to the current traffic lane of the motor vehicle 100.

[0070] Furthermore, according to a second eligibility criterion for exit 210, the path of exit 210 must be tangential to the path of road 200 over a sufficient length so that it is possible to delay the start of deceleration of the motor vehicle 100 in the exit lane 210. For this purpose, the geolocation means allows a determination of the exit lane 210 as being tangent to the first road over a given length greater than the minimum length threshold L_min.

[0071] In one embodiment, the verification of the first and / or second eligibility criterion is carried out by the geolocation means 1. In this case, in step E2, the geolocation system 1 notifies us of the presence of an exit lane 210 in front of the vehicle only if the exit lane 210 complies with the first and second criteria.

[0072] Then, step E2 comprises a second sub-step E23 of determining the given section 220. The given section 220 extends between a start position 221 and an end position 222 framing the first position POS_S, - the start position 221 being defined by a first duration ATI of travel by the motor vehicle 100 of a distance between the start position and the first position, for example a duration ATI of between one second and three seconds, and or - the end position being defined by a second duration AT2 of travel of a distance between the first position and the end position, for example a duration AT2 of between one second and three seconds.

[0073] From a current longitudinal speed V_LONG (t) of the motor vehicle 100 provided by the longitudinal speed sensor 4, the curvilinear abscissa of the entry 221 and exit 222 positions framing the first position POS_S is determined.

[0074] Then, in a third sub-step E24 of step E2, it is checked whether the motor vehicle 100 has reached the given section. For this, the geolocation data DI and the perception data D2 are processed.

[0075] Each time geolocation data Dl is received, the current curvilinear abscissa POS_V(t) of the motor vehicle 100 is compared to the curvilinear abscissa of the start position 221.

[0076] When the current curvilinear abscissa POS_V(t) of the motor vehicle 100 is su- lower than the curvilinear abscissa of the start position 221, then we go directly to step E3.

[0077] Otherwise, as long as the motor vehicle 100 is located upstream of the given section 210, the geolocation data DI and the perception data D2 are considered reliable and are processed as they are received in step E2.

[0078] The second step E2 comprises a determination of a second maximum authorized speed of the motor vehicle 100 as a function of a recognition of a first speed limit sign PI by the detection means 2 and as a function of a location of the motor vehicle 100 on the at least one lane 201, 202, 203 by the geolocation means 1.

[0079] Upon receipt of geolocation data D1, the current location of the motor vehicle 100 is updated, i.e. the curvilinear abscissa and the lane 201, 202, 203 on which the motor vehicle 100 is traveling are updated.

[0080] In one embodiment, at each iteration of step E2, the geolocation data D1 and the perception data D2 are merged together to determine a merged maximum authorized speed VMA.

[0081] Then we loop back to sub-step E24 until the motor vehicle 100 reaches the given section.

[0082] In the third step E3, the route chosen by the vehicle is validated on exit lane 210 or on one of the traffic lanes 201, 202, 203.

[0083] In one embodiment, step E3 comprises a time-delay sub-step E31, during which the motor vehicle 100 travels the given section 220. During sub-step E31, recognition of a second speed limit sign P2 by the perception means 2 does not result in transmission of a new speed limit to the autonomous driving system 20 or to the human-machine interface 30. Similarly, during sub-step E31, location of the motor vehicle 100 on the exit lane 210 by the geolocation means 1 does not result in transmission of a new speed limit to the autonomous driving system 20 or to the human-machine interface 30.

[0084] In other words, during the execution of the sub-step step E31, if the perception means 2 detects a new speed limit sign P2 while the motor vehicle 100 is traveling the given section 220, the speed limit appearing on the new traffic sign will not be taken into account to limit the longitudinal speed of the motor vehicle 100. In addition, if the geolocation means 1 positions the motor vehicle 100 on the exit lane 210, the speed limit associated with the exit lane will not be taken into account to limit the longitudinal speed of the motor vehicle 100.

[0085] Indeed, sub-step E31 is a transitional step during which the data of geolocation data DI and perception data D2 are temporarily less reliable due to the proximity of an exit 210, as previously illustrated with reference to Figures 3 to 5. Thus, temporarily, the geolocation data DI and perception data D2 are not used to position the vehicle on one of the traffic or exit lanes, until substep E31 ends.

[0086] The third step E3 further comprises a sub-step E32 of detecting an action by the driver of the motor vehicle 100 with a view to taking the exit 210. When such an action by the driver is detected, the route chosen by the vehicle is determined and the process then proceeds directly to the fourth step E4 of transmitting the new speed limit LV1 to a human-machine interface of the vehicle, even if the motor vehicle 100 is still traveling on the given section 220.

[0087] Sub-step E32 of detecting an action by the driver with a view to taking exit 210 comprises detecting a use of the direction indicator 3, in particular a use signaling a change of lane in the direction of exit lane 210.

[0088] In addition or alternatively, the sub-step E32 of detecting an action by the driver comprises a detection by the perception means 2 of a crossing of a separation line 211 of the exit lane 210.

[0089] In addition or alternatively, the sub-step E32 of detecting an action by the driver comprises a comparison with a minimum threshold Min_VL of a yaw rate of the motor vehicle 100 measured by the yaw rate sensor 5. In one embodiment, the minimum threshold Min_VL is around 70 kilometers per hour.

[0090] Step E3 also includes a sub-step E33 for exiting the given section, which is executed when the current curvilinear abscissa POS_V(t) of the motor vehicle 100 is greater than the curvilinear abscissa of the end position 222. If the last position reported by the geolocation means 1 positions the motor vehicle 100 on the exit lane 210, we continue with step E4. Otherwise we loop back to step El.

[0091] Alternatively, the exit from the given section could be detected without using GPS positioning. For example, the exit from the given section could be detected upon the lapse of a predefined time delay, measured from the vehicle entering the given section. The predefined time delay could be calculated based on a longitudinal speed of the motor vehicle 100 measured at the vehicle's entry into the given section.

[0092] Step E3 thus ends either when the motor vehicle 100 reaches the end position 222 of the given section 220, or when an action by the driver can be interpreted as a decision to take exit 210.

[0093] We then move on to the fourth step E4 in which we transmit the new maximum authorized speed, or new speed limit LV1, to the system autonomous driving 20 and / or human-machine interface 30.

[0094] In other words, it is considered that after a transitional period corresponding to the crossing of section 220, the geolocation data DI and the perception data D2 are again sufficiently reliable to determine whether the motor vehicle 100 is affected by the maximum authorized speed, or new speed limit LV1, relating to the exit lane 210.

[0095] More generally, the method for automatically defining a maximum authorized speed of the motor vehicle 100 comprises: - a first step of detection El of a new speed limit LV1 by the vehicle's perception means 2, and - a second determination step E2 if the vehicle is located near an exit lane via the geolocation means 1. If the second step has determined that the vehicle is close to an exit lane, we move on to a third step E3 of validation of the route chosen by the vehicle, on the exit lane or not. Then, if the second step has determined that the vehicle is close to an exit lane and if the third step E3 has validated that the vehicle has chosen to follow the exit lane, we continue with a fourth step E4 of transmission of said new speed limit LV 1 to a human-machine interface of the vehicle and / or to an autonomous driving system of the vehicle.

[0096] In one embodiment, the first and second steps are performed in parallel.

[0097] Finally, the definition method according to the invention makes it possible to significantly limit the number of cases, called “false positives”, where a speed limit sign relating to an exit lane is wrongly considered to be relevant for the motor vehicle 100. The occurrence of a “false positive” has very negative consequences on safety and driving comfort, since it causes the motor vehicle 100 to slow down when passing near an exit, while the vehicle remains in its lane. This type of situation increases the risk of accidents and degrades the driver’s confidence in the vehicle’s behavior.

[0098] The invention makes it possible to reduce the number of occurrences of false positives by addressing two causes which are at the origin of most of the “false positives”. A first cause lies in the difficulty of categorizing speed limit signs placed near the exit lanes; a second cause lies in a transient error in the positioning of the motor vehicle 100.

[0099] The implemented solution is based on a probabilistic principle: most of the time, the motor vehicle 100 continues on its way without taking an exit. Therefore, as long as the motor vehicle 100 is not located on the exit lane 210 by the geolocation system 1, a speed limit detected in a section of road near the exit will not be implemented.

[0100] Furthermore, in order to prevent cases where the motor vehicle 100 is wrongly located on the exit lane by the geolocation system 1, the method according to the invention implements a waiting phase, or timeout phase, i.e. a period during which the positioning of the vehicle on the exit lane is not taken into account; at the end of this period, it is considered that the probability that the position reported by the GPS is correct is sufficiently high. It is therefore considered that the GPS locates the motor vehicle 100 on the lane where it is actually located.

[0101] The implementation of the invention delays the start of braking when the vehicle takes an exit. The braking of the vehicle is therefore less comfortable but it is carried out in conditions meeting safety standards, in particular the invention applies to so-called tangential exits and the length of which makes it possible to delay the start of braking. In addition, if the driver signals his intention to take the exit, by using a turn signal, or by modifying the curvature of his trajectory, the method according to the invention will detect these signals and interrupt the timing phase.

[0102] Tests of a vehicle equipped with the invention were conducted in a real-life situation on a national road known for its ability to induce numerous false positives. Without implementing the invention, 40 false positives were measured on this road; with implementing the invention, the number of false positives decreased to four, which represents a 93% reduction in false positive cases. The remaining four false positives are due to incorrect location of the vehicle by the GPS.

[0103] Thus, the method of automatically defining a maximum authorized speed according to the invention improves driving safety, the reliability of vehicle behavior, user comfort and the driver's acceptance of vehicle behavior.

[0104] Furthermore, the implementation of the invention only requires a front camera and a GPS-type geolocation system associated with a standard definition map, these devices being commonly present on vehicles.

Claims

Claims

1. Method for automatically defining a maximum authorized speed (MAS) of a motor vehicle (100) moving on a road (200), the vehicle being equipped with a means (2) for perceiving the environment of the motor vehicle (100) and a means (1) for geolocating the motor vehicle (100) on a map (11), characterized in that it comprises: • a first step of detection (El) of a new speed limit (LV1) by the perception means (2) of the vehicle; • a second step of determining (E2) a location of the motor vehicle (100) near an exit lane (210) of the road (200) by means of the geolocation means (1); • if the second step (E2) has determined that the vehicle is close to an exit lane (210), a third validation step (E3) of a route chosen by the motor vehicle (100) on the exit lane or not; then • if the third step (E3) has validated that the route chosen by the motor vehicle (100) takes the exit lane (210), a fourth step of transmission (E4) of said new speed limit (LV1) to a human-machine interface of the vehicle (30) and / or to an autonomous driving system (20) of the motor vehicle (100).

2. Definition method according to the preceding claim, characterized in that the third validation step (E3) comprises a time delay.

3. Definition method according to one of the preceding claims, the motor vehicle comprising direction indicators (3), and a yaw rate sensor (5), characterized in that the third validation step (E3) comprises a detection of use of a direction indicator (3) by a driver of the motor vehicle (100), and / or a detection, by means of the perception means (2), of a crossing of a separation line of the exit lane (211), and / or a detection of a crossing of a minimum threshold (Min_VL) by a yaw rate of the motor vehicle (100) measured by the yaw rate sensor (5) and / or a location of the motor vehicle (100) on the exit lane or not by means of the geolocation means (1).

4. Definition method according to one of the preceding claims, the motor vehicle traveling on a first road (200) comprising at least one traffic lane (201, 202, 203) and an exit lane (210) located in front of the motor vehicle (100), characterized in that the second step (E2) comprises a determination by the geolocation means (1) of a given position (POS_S) of the exit lane (210), and a definition of a given section (220) of the first road (200) framing the given position (POS_S).

5. Definition method according to the preceding claim, characterized in that a maximum authorized speed (VMA) applicable on a lane (201, 202, 203) of the given section (220) of the first road (200) is greater than a minimum speed threshold (LIM_min), for example greater than 70 km / h, and / or in that the exit lane (210) is tangent to a lane (201, 202, 203) of the first road (200) over a given length (L_tan) greater than a minimum length threshold (L_min).

6. Definition method according to one of the preceding claims, characterized in that the given section (220) extends between a start position (221) and an end position (222) framing the first position (POS_S), the start position (221) being defined by a first duration (ATI) of travel by the motor vehicle (100) of a distance between the start position (221) and the first position (POS_S), for example a duration of between one second and three seconds, and / or the end position (222) being defined by a second duration (AT2) of travel of a distance between the first position (POS_S) and the end position (222), for example a duration of between one second and three seconds.

7. Device (10) for automatically defining a maximum authorized speed of a motor vehicle (100) equipped with a means of perception (2) of the environment of the motor vehicle (100) and of a means of geolocation (1) of the motor vehicle (100) on a map (11), the device comprising hardware and / or software elements (1, 2, 3, 4, 5, 6, 11, 61, 62, 63, 611, 612, 613, 614) implementing the method according to one of claims 1 to 6, in particular hardware elements (1, 2, 3, 4, 5, 6, 11, 61, 62, 63) and / or software designed to implement the method according to one of the preceding claims, and / or the device comprising means for implementing the method according to one of the preceding claims.

8. Computer program product comprising program code instructions recorded on a computer-readable medium for implementing the steps of the method according to any one of claims 1 to 6 when said program operates on a computer or computer program product downloadable from a communication network and / or recorded on a data medium readable by a computer and / or executable by a computer, characterized in that it comprises instructions which, when the program is executed by the computer, cause the latter to implement the method according to any one of claims 1 to 6.

9. A computer-readable data storage medium on which is recorded a computer program comprising program code instructions for implementing the method according to one of claims 1 to 6 or according to claim 8 or a computer-readable storage medium comprising instructions which, when executed by a computer, cause the latter to implement the method according to any one of claims 1 to 6.

10. Signal of a data carrier, carrying the computer program product according to claim 8.

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