FR3049560B1 - METHOD AND SYSTEM FOR ASSISTING THE CHANGE OF THE TRACK TRACK FOR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a lane-assisting method for a motor vehicle (2) from an initial taxiway (L1) to a final taxiway (L2), the method comprising a step of detecting the lane of final driving (L2), and a control step of the motor vehicle (2) so that it rejoins the final driving lane (L2) in a predetermined lane changeover time. According to the invention, the method further comprises a step of determining at least one characteristic parameter of the driving behavior of a driver of said motor vehicle (2), and said lane changeover time is predetermined and set according to said at least one parameter.

Description

METHOD AND SYSTEM FOR ASSISTING THE CHANGE OF THE TRACK TRACK FOR A MOTOR VEHICLE

The present invention generally relates to motor vehicles equipped with semi-automatic or even automatic driver assistance systems, and more specifically assistance systems for the change of driving lane for a motor vehicle.

Such lane change systems, known as LCC (English initials set for Lane Change Control), aim to control, by acting on the control members of the steering of the vehicle or the braking system, the path followed by a motor vehicle when it is necessary to change the driving lane, for example when passing another vehicle or after passing a vehicle.

Such systems generally use information from a road marking line detector, such as an on-board camera at the front of the vehicle, to identify the lateral boundaries not only of the track on which the vehicle is traveling, but also tracks adjacent to the current taxiway. When the vehicle is in a situation where a change of lane, from an initial taxiway to a final taxiway, is possible, the conventional systems generally calculate the central trajectory of the final taxiway, and determine from information from a vehicle location system, for example a navigation system, and vehicle speed and / or acceleration information, a trajectory that must be followed by the motor vehicle to make it reach the central trajectory of the final taxiway. The conventional systems then control the vehicle so that it follows this path automatically until reaching the central path of the final taxiway. By way of example, FIG. 1 shows a driving situation on a road 1, for example a motorway, comprising, within two extreme lateral limits 10 and 11, three possible taxiways.

Li, l_2 and L3 in the same direction of travel, each being delimited by two marking lines on the ground, such as the marking line 13. A motor vehicle 2 equipped with a lane departure assistance system is shown rolling on the taxiway Li located here the rightmost of the road 1 in the direction of the traffic. The motor vehicle 2 follows in the example a third vehicle 3 that it is about to overtake using the lane assistance system. For the sake of simplification, it is assumed that the system has already identified the initial taxiway, here the Li track, the final taxiway, here the L2 lane, and that the lane change is indeed possible (ground marking allowing the lane change, no third-party vehicle on the final taxiway likely to interfere with overtaking, for example a third-party vehicle at the rear of the vehicle 2). In this case, a conventional lane-assisting system will determine the central trajectory Le of the final taxiway L2, and then determine the trajectory P to be followed by the vehicle 2 to bring the vehicle onto the central trajectory. .

The lane change maneuver is usually initiated after the driver or system has verified that a lane change was possible, and that the driver has activated the direction indicator. The duration T necessary to allow the motor vehicle 2 to join the central path Lc is fixed, generally of the order of 5 seconds.

Such systems do not always give a feeling of safety for the driver. In particular, some drivers of calm nature will find that the maneuver is too fast, while other drivers, with more aggressive driving, will instead consider that the maneuver is too slow compared to what they would have done them -Same.

Also known from US 2012/0215415 a driving assistance system that uses a determination of at least one characteristic parameter of the acceleration behavior of a driver of the motor vehicle. The system is then able to regulate the speed of the vehicle according to this parameter. Lane change procedures are not supported by the system described. The invention aims to overcome the disadvantages and limitations of known systems by providing a change of lane assistance that tends to approach the natural behavior of a motorist and to increase accordingly his sense of security.

To do this, the subject of the present invention is a lane-assisting method for a motor vehicle from an initial taxiway to a final taxiway, the method comprising a step of detecting the final taxiway, and a control step of the motor vehicle so that it rejoins the final taxiway in a predetermined lane change time, characterized in that it further comprises a step of determining at least one characteristic parameter of the behavior of the vehicle. driving a driver of said motor vehicle, and in that said lane changeover time is predetermined and set according to said at least one parameter.

The characteristic parameter of the driving style of a driver may for example be related to accelerations / decelerations made by a driver.

Alternatively or in combination, the driving style can also be determined from other measurements, for example by steering angle tracking (steering angle) when a driver manually makes a lane change.

In addition, some known systems alert the driver or prevent the automatic lane change maneuver, when traffic conditions do not allow it. Figure 2 illustrates the surveillance areas close to the motor vehicle 2 that allow such systems to offer this functionality. For the sake of simplicity, only the surveillance zones located in the left lane with respect to the driving lane of the motor vehicle 2 have been represented, but it is easily understood that similar zones are provided on the right side of the motor vehicle 2. first surveillance zone shown in Figure 2, at the height of the motor vehicle 2, forms a zone Αχ said safety zone which prevents automatic change of lane when a third vehicle is detected as being present in this area . The length of the zone Ai, taken in the rolling direction, is predefined with respect to the front and rear of the motor vehicle 2 and thus also takes into account the length of the motor vehicle 2. In the example shown, this zone Ai extends over 12 meters with respect to the front of the vehicle 2, and 3 meters with respect to the rear of the vehicle 2. The width of the zone Ai is also defined as being at least the width of the final taxiway (typically of the order of 3.5 meters for a motorway in France), preferably increased by a safety margin, for example of the order of 0.5 meters, encroaching on the taxiway of motor vehicle 2, to advantageously account for two-wheel vehicles likely to roll between the two lanes.

A second zone A2, forming a rear surveillance zone, is also observed by appropriate components of the system (cameras, radars ...). This zone A2, which starts immediately behind the safety zone Ai, may have a width identical to the safety zone Αχ, and a predefined length, fixed in the example to 67 meters. The observation of this rear surveillance zone makes it possible to give a lane change authorization under certain conditions only. The principle is as follows: the lane change is authorized by the system if no third party vehicle has been detected as present in this zone A2. If, however, as shown in Figure 2, a third vehicle is detected on the final taxiway, as occurring at the rear of the vehicle 2, the system will estimate, from a determination of the positions and relative speeds of the vehicle. detected third vehicle and the vehicle 2, a duration TTC (English initials set for Time To Collision) corresponding to the time that would elapse until a collision between the motor vehicle 2 and the third vehicle detected in the case where the system authorize the overrun. A first TTCth-re threshold, for example set at 5 seconds, will serve as a comparison value with the estimated TTC duration to allow or not the change of lane. More specifically, a lane change will be authorized if the estimated TTC duration is greater than the first TTCth-rez threshold and prohibited in the opposite case.

Some more sophisticated systems do the same for traffic monitoring in a third zone A3, forming a front surveillance zone. This zone A3, which starts immediately ahead of the safety zone Αχ, may have a width identical to the safety zone Αχ, and a predefined length, fixed in the example at 58 meters. In a manner analogous to that described for the rear surveillance zone A2, for any third vehicle detected in this zone A3, it is estimated that a duration TTC that is compared with a second threshold TTCth-fr, fixed for example at 7 seconds. The automatic lane change maneuver will be authorized if the estimated TTC duration is greater than the second TTCth-fr threshold, and prohibited in the opposite case.

To correspond to this type of system, and according to other possible aspects of the method: the method may further comprise a step of monitoring a safety zone located on the final taxiway, on one side of the motor vehicle, in such a way as to prohibit any change of lane in the event of detection of the presence of a third-party vehicle in this safety zone; said safety zone extends over a predetermined length as a function of the length of the motor vehicle, a predefined front safety distance from the front of the motor vehicle, and a predefined rear safety distance from from the rear of the motor vehicle; advantageously, said safety distance before and / or said rear safety distance also varies according to said at least one characteristic parameter of the driving behavior of a driver of said motor vehicle; the method preferably further comprises a step of monitoring at least one surveillance zone located on the final driving lane, at the front or rear of said safety zone, comprising a preliminary substep of receiving detection information of a third-party vehicle present in said at least one surveillance zone, for determining the relative position and speed of said motor vehicle and the detected third-party vehicle, for estimating a duration TTC corresponding to a time that would elapse until a collision between said motor vehicle and the detected third-party vehicle, and comparing the estimated TTC duration to a threshold value, and the lane change is prohibited if the estimated TTC duration is less than said threshold value; - Again, said threshold value may advantageously vary according to said at least one characteristic parameter of the driving behavior of a driver of said motor vehicle; said at least one surveillance zone is for example a rear surveillance zone associated with a rear threshold value TTC, It is also possible to provide a front monitoring zone associated with a threshold value before TTC. A complete system will advantageously combine the front and rear surveillance zones; said determining step comprises a sub-step of classifying a driver in one of a plurality of representative categories of driving behavior according to said at least one parameter, and the lane change duration T is set to a value belonging to at an interval between a minimum duration Tmin and a maximum duration Tmax, the minimum duration Tmjn and the maximum duration Tmax depending on the category. The invention also relates to a lane-assisting system for a motor vehicle from an initial taxiway to a final taxiway, the system comprising means for detecting the final taxiway, and means for controlling the motor vehicle so that it rejoins said final taxiway in a predetermined lane changeover time, characterized in that it furthermore comprises means for determining at least one characteristic parameter of the driving behavior of a driver of said motor vehicle, and in that said control means are adapted to set said lane change time according to said at least one parameter. The invention and the various advantages it affords will be better understood from the following description, made with reference to the appended figures, in which: FIG. 1, already described above, describes an example of a rolling situation to intervene a change of lane made with a known system of assistance to the change of lane; FIG. 2, already described above, illustrates various surveillance zones that can be examined in the context of a lane change authorization; FIG. 3 represents, in the form of a simplified block diagram, a possible general architecture of a lane-assisting system capable of implementing the method according to the invention; - Figure 4 schematically illustrates steps of a lane change assistance method.

In the rest of the description, and unless otherwise stated, the elements common to all the figures bear the same references.

FIG. 3 is a simplified illustration of an on-board lane-assist system 4 for a motor vehicle from an initial taxiway to a final taxiway. In the nonlimiting example shown in this figure, the system 4 cooperates with other elements present on the vehicle, in particular with a road marking line detector 5, for example a camera located at the front of the motor vehicle, a system 6 for locating the motor vehicle, for example a GPS-type navigation receiver, and various sensors 7 making it possible to determine the current speed and / or the acceleration of the motor vehicle. The system 4 also cooperates with a system 8 for checking the steering column of the vehicle, or even with a braking system (not shown). It should be noted that the detector 5 could also be integrated into the system 4 without departing from the scope of the present invention. The system comprises, in a preferred version, a set 9 of sensors (cameras, radars, lidars, etc.) allowing the monitoring of different zones in the environment close to the motor vehicle 2, such as the safety zone Αχ, and the A2 or A3 front surveillance zones described above, for the purpose of detecting the presence of one or more third-party vehicles.

The reference 40 in FIG. 2 represents means for detecting the possible taxiways at the front of the vehicle, and in particular the initial taxiway and the final taxiway. These means 10, for example in the form of a dedicated processing module, receive the information from the detector 5, in this case the images captured by the camera, and extract from this information the road marking lines of the various tracks located at the front of the camera. vehicle, including the final taxiway for the change of lane defined laterally by two marking lines. Different processing algorithms exist to allow the detection of possible rolling paths, and do not need to be further detailed because without affecting the method according to the invention.

The system 4 also conventionally comprises means 41 for determining a central path With respect to the final taxiway that has been detected as well as means 42 for controlling the motor vehicle so that it rejoins the central trajectory Le. The central trajectory Le is for example determined from the detection of two road marking lines laterally delimiting the detected final taxiway.

The control means 42 are particularly capable of determining a trajectory to be followed by the motor vehicle 2 to go from the initial taxiway to the final taxiway by joining the central trajectory Le (trajectory P in FIG. 1), then to act on the system 8 for controlling the steering column of said motor vehicle, or even on the braking system, to guide the car automatically during the lane change maneuver.

In the following, the following variables are defined: - Xj is the initial position of the motor vehicle 2; - Xf is the final position of the motor vehicle 2; - Vj is the initial speed of the motor vehicle 2; - Vf is the final speed of the motor vehicle 2; - A, is the initial acceleration of the motor vehicle 2; Af is the final acceleration of the motor vehicle 2; - T represents the time required to operate the lane change maneuver.

The trajectory that the motor vehicle must follow is predefined and obeys the following order 5 polynomial function:

in which the duration T is the input data and with:

As indicated in the introduction, the systems of the prior art use a fixed duration T, of the order of 5 seconds.

In a different way, the invention provides for determining beforehand at least one characteristic parameter of the driving behavior of a driver of the motor vehicle 2, and of varying at least the duration T of the lane change as a function of this parameter.

The determination of the characteristic parameter of the driving behavior of the driver can be done according to the teachings of US 2012/0215415, observing the acceleration / deceleration performed by the driver. For example, comparison thresholds and speeds or accelerations of the vehicle 2 are used to categorize the behavior.

of a driver in several, for example in three categories, a first category corresponding to a driver "quiet", a second category corresponding to a driver "normal", and a third category corresponding to a driver "aggressive". Other methods may be used in addition or alternatively to characterize a specific conductor behavior to the change of lane: - measurement of one or more of the following parameters: steering angle, lateral speed, lateral acceleration, yaw rate and / or couple flying during several manual lane changes. The measurements are then compared with typical curves or values corresponding to the desired behaviors (calm, nominal, abrupt ...); - measurement of the average lane change time in manual.

In a basic implementation of the invention, for the duration T of the automatic lane change maneuver, a value of the order of 6.5 seconds is used for the "normal" drivers, whereas this value T will be more low (typically of the order of 4.5 seconds) for "aggressive" drivers who would naturally tend to operate more quickly a change of lane, and that this value T will be larger (typically of the order of 7 seconds) for "quiet" drivers who would naturally tend to operate a lane change more slowly.

In a more complex implementation of the invention, in which the assistance system comprises means capable of monitoring zones on the side, front and / or rear of the vehicle 2 (typically cameras, radars). and / or lidars embedded on the vehicle 2, generally represented by the reference 9 in FIG. 3, it is also considered that the characteristic parameter of the driving behavior of a driver of the motor vehicle 2 will advantageously be able to be used to modify the conditions enabling to authorize or not a change of lane, in the case of detections of the presence of a third-party vehicle in one of the surveillance zones Ai, A2 or A3 described above with reference to Figure 2. Concerning the zone Ai safety principle, the principle is to increase the front and / or rear safety distances for "quiet" drivers, and to reduce these same safety distances forward and / or backward for "Aggressive" drivers In other words, the quieter the driver, the longer the safety zone Ai. With regard to the A2 rear surveillance zone or the A3 front surveillance zone, the principle is to increase the value of the TTCth re rear threshold, respectively before TTC for "quiet" drivers, and to reduce this same threshold value. backward TTC ^ æ, respectively beforeTTC ^ en for "aggressive" drivers. In other words, the more aggressive the driver, the lower the threshold values TTC ^, respectively beforeTTCth fr, are low, thus reflecting much better the behavior of this type of drivers.

In a preferred embodiment, for each class of conductors, two limiting values T are defined. and T for the min max duration T required for a lane change maneuver.

Table 1 below gives an example of the different values that can be adopted in a lane-assist system according to the present invention, depending on the category of the driver.

Table 1

For each category of drivers, the way to determine the duration T necessary for the change of lane preferably obeys the following rules (assuming of course that no third vehicle has been detected in the safety zone Al, which would prohibit in this case any change of lane maneuver), so as to have a duration adapted to the traffic conditions: - If at least one TTC duration estimated for a third vehicle detected in any of the rear surveillance zones A2 or before A3 is substantially equal to the threshold value corresponding to the surveillance zone considered (TTCth re for Surveillance Zone A2 and TTCfh_fr for

Surveillance Zone A3), then we find ourselves in a situation in which the lane change maneuver should last as short as possible. In this case, the duration T is set equal to the minimum duration Tmjn.

- If, on the contrary, all estimated times TTC are higher than the threshold value of the surveillance zone considered, increased by a margin of safety, then one finds oneself in a situation in which the maneuver of lane change can last longer . In this case, the duration T is set equal to the maximum duration Tmax. The safety margin is for example given by the difference between Tmax and Tmjn. - In all other cases which are intermediate, that is to say if all the estimated durations TTC are between the threshold value of the surveillance zone considered, and this threshold value increased by the safety margin, the duration T must be set to a value between the minimum duration Tmin and the maximum duration Tmax, defined for example according to the following relation:

wherein TTCfr is an estimated time for a third vehicle detected in the area before A3, and TTCre is an estimated time for a third vehicle detected in the rear area A2.

FIG. 4 summarizes the steps of a lane-assisting method for a motor vehicle from an initial taxiway to a final taxiway according to the present invention, in its most elaborate form:

The method starts with a step 100 of detection of the final taxiway, for example by the processing of the images captured by a camera 2 for extracting the road marking lines located at the front of the vehicle.

The method then continues with a step 110 of determining at least one characteristic parameter of the driving behavior of a driver of the motor vehicle 2, allowing the classification of the driver in one of several categories.

Step 120 corresponds to the monitoring of the security zone Ai. The lane change procedure terminates without a lane change if a third vehicle is detected in this safety zone Ai. As seen above, the length of the surveillance zone is preferably adapted to the type of conductor. Step 130 corresponds to the surveillance of the rear surveillance zone A2 and / or before A3. The lane change procedure terminates without a lane change if a third party vehicle is detected in one of these zones, for which the estimated TTC duration is less than the threshold value of the surveillance zone considered. As seen above, the threshold values are also preferably adapted to the type of conductor.

The last step 140 represented corresponds to the step of controlling the motor vehicle 2 so that it rejoins the final driving lane L2 in a lane change time T, defined in accordance with the invention, with the type of conductor.

Claims (11)

SiïiMŒmsm A method of assisting the change of flight for a motor vehicle (2) from an initial taxiway (Lj) to a final taxiway (La) / the method comprising a step (100) for detecting the taxiway final driving (La), and a step (140) for controlling the motor vehicle (2) so that it rejoins the final driving flight (La) in a predetermined lane departure time (T), said method further comprising a step (110) of determining at least one parameter characteristic of the driving behavior of a driver of said motor vehicle (2), said duration (T) of lane change being predetermined and set according to said at least one parameter; said method also further comprising a step (120) of monitoring a safety zone (Ai) located on the final taxiway (Lz), on one side of the motor vehicle (2), so as to prohibit any change of flies when a third vehicle is detected in this safety zone, said safety zone (Ai) extending over a predetermined length depending on the length of the motor vehicle (2) f a safety distance predefined front from the front of the motor vehicle (2), and a predefined rear safety distance from the rear of the motor vehicle (2), characterized in that said safety distance before and / or the said rear safety distance varies according to said at least one characteristic parameter of the driving behavior of a driver of said motor vehicle (2), 2, Method according to any one of claims 1, characterized in that it further comprises further comprises a step (130) for monitoring at least one monitoring zone (A- ?, A3) located on the track of the final run (Lz), at the front or rear of said safety zone (Ai), comprising a preliminary step of receiving a third vehicle detection information (3 '; said at least one monitoring zone (Az, Â3), for determining the relative position and speed of said motor vehicle (2) and the detected third-party vehicle, for estimating a duration TTC corresponding to a time which is would flow to a collision between said motor vehicle (2) and the detected third-party vehicle, and to compare the estimated TTC duration to a threshold value, and that the lane change is prohibited if the estimated TTC duration is less than said threshold value, 3, Method according to claim 2, characterized in that said threshold value varies according to said at least one characteristic parameter of the driving behavior of a driver of said motor vehicle (2). 4, Method according to any one of claims 2 or 3, characterized in that said at least one surveillance zone is a rear monitoring zone (Α2) associated with a rear threshold value TTC, v tn ~ re. ? 5, Method according to any one of claims 2 or 3, characterized in that said at least one monitoring zone is a front monitoring zone (Ag) associated with a threshold value before TTC & . 6, Process according to any one of claims 2 to 5, characterized in that said determining step (110) comprises a substep of classifying a driver in one of a plurality of categories representative of driving behaviors according to of said at least one parameter, and in that the flight change duration (T) is set to a value belonging to an interval comprised between a minimum duration Tm; n and a maximum duration Tmax, I® minimum duration Tmhi ®t the maximum duration Tmax depending on the category. 7, Method according to any one of the preceding claims, characterized in that said at least one parameter comprises accelerations / decelerations of the vehicle. 8, method according to any one of the preceding claims, characterized in that said at least one parameter comprises steering angle measurements during flight changes. 9. A system for assisting a change of lane for a motor vehicle (2) from an initial taxi (Li) to an anal taxi (Lz), the system comprising means (40) for detecting the taxiway. run (L2) * and control means (42) of the motor vehicle (2) to join said final driving vote (La) in a predetermined lane change time (T), said system further comprising means for determining at least one characteristic parameter of the driving behavior of a driver of said motor vehicle (2), said control means (42) being able to set said flight change duration (T) according to said least one parameter, said system also further comprising means of monitoring a safety zone (Ai) located on the final driving vote (Ls) * on one side of the motor vehicle (2) * so as to prohibit any change flying when detected e presence of a third vehicle in this safety zone * said safety zone (Αχ) extending over a predetermined length according to the length of the motor vehicle (2), a predefined forward safety distance from the front of the motor vehicle (2) * and a predefined rear safety distance from the rear of the motor vehicle (2) * characterized in that said safety distance before and / or said rear safety distance varies according to said at least one characteristic parameter of the driving behavior of a driver of said motor vehicle (2). , 10.System according to claim 9 * characterized in that the means (40) for detecting the final driving lane are able to receive images captured by an onboard camera (5). 11.System according to any one of claims 9 to 10, characterized in that the means (42) for controlling the motor vehicle (2) are able to act on a system (8) for controlling the steering column of said vehicle. automobile (7), or even on a braking system.