Method and system for controlling the speed of a vehicle

Abstract

A method for controlling the speed of a vehicle in a lane is disclosed, comprising the following steps: obtaining (E10) at least a first piece of information about the lane and, optionally, at least a second piece of information about external conditions; determining (E20) from the at least one first piece of information the lane width and, optionally, the length of the lane that is visible to a driver of the vehicle; calculating (E30) a suitable speed for the vehicle depending on the maximum authorized speed in the lane, the determined lane width, and the determined visible lane length and / or the external conditions; and adjusting (E40) the vehicle speed as a function of the calculated speed.

Description

[Technical Field]

[0001] The present invention relates to a method for controlling the speed of a vehicle. The present invention also relates to a system for controlling the speed of a vehicle. The present invention further relates to a vehicle including such a system. The present invention also relates to a computer program product for implementing the above-mentioned method. The present invention also relates to a storage medium on which such a program is stored. Finally, the present invention relates to a signal from a data storage medium carrying such a computer program product. [Background technology]

[0002] Some automobiles are equipped with automatic adaptive speed control systems of the ACC (acronym for adaptive cruise control) type. Such systems make it possible to adapt the speed of the vehicle, among other things, depending on the speed of the vehicle in front of it. These systems make it possible to regulate the speed of the vehicle to about a fixed value when no vehicles or obstacles are detected in front of the vehicle.

[0003] Known as "situational ACC" or "smart ACC" systems, these systems make it possible to adapt the speed of a vehicle depending on the situation it is traveling in, for example when signs displaying the recognized legal speed limit are present. In cars equipped with a situational ACC system, the speed of the vehicle is managed by this system.

[0004] ACC systems are known in which the speed of a vehicle is generally adapted according to the vehicle or the vehicle in front of it, to speed limit signs (seen by a camera positioned in front of the vehicle or embedded in the map as ADAS (acronym for Advanced Driver Assistance Systems) information), to map information providing information about the curvature of curves, about the gradient, and to information about the various situations encountered (intersections, roundabouts, etc.).

[0005] However, these solutions have drawbacks. In particular, such systems may cause anxiety for the vehicle driver and passengers. Specifically, driving in a straight line at the maximum speed permitted by regulations on certain lanes may not be easily accepted. These are, for example, roads without road markings (known as country or regional roads). Usually, the roads are too narrow or winding, and driving at the speed limit may prove dangerous. For example, on country roads, even if narrow, the authorized legal maximum speed is 80 km / h unless there is some other speed limit indicated by a speed limit sign. However, if a vehicle were to travel at this speed on such a road, it would likely cause anxiety for the vehicle driver. If the vehicle were not equipped with an ACC system, the vehicle driver would likely slow down the vehicle to reassure himself. If the vehicle were equipped with a speed regulator, the vehicle driver would also likely tend to adjust the cruising speed to a value lower than the speed permitted by regulations. If a vehicle is equipped with a situational ACC system, it is conceivable that drivers will, unfortunately, have a tendency to disable this system. Summary of the Invention

[0006] The object of the present invention is to provide a method and a system for controlling the speed of a vehicle that overcomes the above-mentioned drawbacks and improves the methods and systems for controlling the speed of a vehicle known from the prior art. In particular, the present invention makes it possible to provide a method and a system that is low-cost and makes it possible to manage the speed of a vehicle by replicating human behavior in order to maintain a level of comfort, reliability and safety in the vehicle.

[0007] According to the present invention, a method for controlling the speed of a vehicle on a lane comprises the following steps: - obtaining at least one first piece of information about the lane and at least one second piece of information about external conditions; - determining a lane width and, optionally, a lane length visible to a driver of said vehicle based on said at least one first piece of information; - calculating a suitable speed for the vehicle depending on the maximum authorized speed on said lane and depending on said determined lane width and depending on said determined visible lane length and / or external conditions; and adjusting the speed of the vehicle in response to the calculated speed.

[0008] During the calculation step, the velocity is calculated as a function V=V legal -(a / W+b / L), where V legal is the maximum authorized speed on said lane, W is the lane width determined during the determining step, and L is the visible lane length determined during the determining step.

[0009] According to one variant, during the calculation step, the velocity is calculated as a function V=V legal -(a / W)c, where V legal is the maximum speed authorized on said lane, W is the lane width determined during the determining step, and c is a weighting factor depending on external conditions.

[0010] According to one variant, during the calculation step, the velocity is calculated as a function V=V legal -(a / W+b / L)c, where V legal is the maximum authorized speed on said lane, W is the lane width determined during the determining step, L is the visible lane length determined during the determining step, and c is a weighting factor depending on external conditions.

[0011] During the obtaining step, the at least one first information regarding the lane may be obtained using a camera and / or a map and / or a lidar.

[0012] The present invention also relates to a system for controlling the speed of vehicles on a lane, comprising software and / or hardware elements implementing the method defined above, in particular software and / or hardware elements designed to implement the method defined above, and / or comprising means for implementing the method defined above.

[0013] The invention also relates to a motor vehicle including a system as defined above.

[0014] The invention also relates to a computer program product comprising program code instructions stored on a computer readable medium for carrying out the steps of the method defined above when said program is run on a computer, or a computer program product stored on a data medium downloadable from a communications network and / or readable and / or executable by a computer, said computer program comprising instructions for causing a computer to carry out the method defined above when said program is run by said computer.

[0015] The invention also relates to a computer readable data storage medium having stored thereon a computer program comprising program code instructions for carrying out the method defined above, or a computer readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method defined above.

[0016] Finally, the invention relates to a signal from a data carrier carrying a computer program product as defined above.

[0017] The accompanying drawings show, by way of example, an embodiment of a speed control system according to the invention and of a way of carrying out the speed control method according to the invention. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 illustrates an embodiment of a system for controlling the speed of a vehicle. [Figure 2] 1 is a flowchart of a manner of performing a method for controlling the speed of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention proposes a method and a system for controlling the speed of a vehicle that can approximate human behavior, particularly in narrow lane conditions, by automatically correcting the speed of the vehicle depending on the lane width. To achieve this goal, the present invention proposes the use of information that is, inter alia, already available, that is used, for example, to keep the vehicle within the lane.

[0020] Advantageously, the invention proposes further deceleration of the vehicle depending on the external conditions, in particular in the event of rain, frost, snow or depending on the weather conditions at night, information about the external conditions being likewise already available, for example provided by temperature and / or light sensors.

[0021] An example of a vehicle 100 equipped with one embodiment of a speed control system 1 will now be described with reference to FIG.

[0022] The vehicle 100 may be a motor vehicle such as a car, truck, or motorcycle.

[0023] The vehicle 100 is intended to be driven on a lane or road segment.

[0024] The vehicle 100 may include a situational ACC system.

[0025] Vehicle 100 includes a speed control system 1 according to one embodiment of the present invention.

[0026] The system 1 may comprise means 3 for obtaining at least one first piece of information regarding the lane and, optionally, at least one second piece of information regarding the external conditions.

[0027] The obtaining means 3 are capable of providing at least one first piece of information regarding the lane, making it possible to determine the lane width and, optionally, the visible lane length.

[0028] "Lane width" means the dimension of a road lane perpendicular to the direction of travel of vehicles on the lane.

[0029] "Lane length" or "visible lane length" means the distance along the direction of travel of a vehicle on a lane that the lane is visible to the driver.

[0030] Preferably, the acquisition means 3 may be located in front of the vehicle 100, at the front of the vehicle.

[0031] The acquisition means 3 include, for example, a camera and / or a map, in particular a digital map, and / or a LIDAR (acronym for Light Detection and Ranging).

[0032] The camera may be, for example, a visible light or infrared camera. Preferably, the camera may be a front-facing camera.

[0033] Advantageously, the acquisition means 3 may also be able to provide at least one second piece of information relating to external conditions, in particular climatic conditions.

[0034] The acquisition means 3 may also include various sensors, for example, an optical sensor and / or a temperature sensor.

[0035] The system 1 may also include a control means or unit 5 .

[0036] The control means 5 is, for example, a computer.

[0037] The control means 5 are able to determine the lane width from the above-mentioned at least one first information provided by the acquisition means 3, in particular from the images provided by the camera.

[0038] The control means 5 may also be able to determine the visible lane length from the above-mentioned at least one first information provided by the acquisition means 3, in particular from the image provided by the camera.

[0039] The control means 5 may also be able to determine a weighting factor c relating to external conditions, in particular climatic conditions.

[0040] For example, the following condition: - Automatic continuous triggering of the wipers for periods longer than 30 seconds, and / or - Automatic low beam headlamps activation via light sensor is satisfied, the coefficient c adopts the value of 1.1, which corresponds to a 10% increase in the slowdown.

[0041] The system 1 may also include a computing means 7 .

[0042] The calculation means 7 is, for example, a computer.

[0043] The system 1 may include two separate computers 5 and 7 .

[0044] According to one variant, the calculation means 7 may be formed by the same computer as the control means 5. In this case, the system 1 comprises a single on-board computer.

[0045] The calculation means 7 is intended to calculate a suitable speed to be applied to the vehicle depending on the lane width determined by the control means 5 and, optionally, depending on the visible lane length determined by the control means 5 and / or a weighting factor relating to external conditions, in particular climatic conditions.

[0046] The velocity may be determined by a velocity function as follows: [Formula 1] V=V legal -(a / W+b / L) where: V legal : Certified maximum speed W: Lane width L: Visible lane length

[0047] To calculate the deceleration, a division by lane width and by visible lane length is performed, since the lower these parameters are, the greater the risk to the vehicle. Thus, the smaller the lane width and visible lane length, the greater the required deceleration.

[0048] Such a function makes it possible to take into account lane narrowing and, another aggravating factor, the winding nature of the road.

[0049] The coefficients a and b may be determined by feedback from tests performed on the vehicle.

[0050] For example, the coefficient a is, for example, 0 to 50, for example, about 40. The coefficient b is, for example, 0 to 300, for example, about 250.

[0051] For example, on a rural road with no road markings and a speed limit of 80 km / h, if the lane width W is 3.5 m and the visible lane length L is 35 m, then the vehicle speed V can be calculated as 61 km / h using the following formula: [Formula 2] V=80-(40 / W+250 / L)

[0052] Preferably, the function of velocity V is limited by a normal boundary.

[0053] If the lane width W is greater than or equal to the first limit A, for example 5.50 m, which corresponds to the standard lane width, the parameter a is not taken into account, and therefore no lane width-dependent slowdown is applied.

[0054] If the visible lane length is equal to or greater than a second limit B, for example 100 m, then parameter b is not taken into account, and therefore no speed reduction according to the visible lane length is applied.

[0055] According to a particularly advantageous variant, the speed can be determined by a speed function as follows: [Formula 3] V=V legal -(a / W+b / L)c where: V legal : Certified maximum speed W = lane width L: Visible lane length c: Weighting coefficient depending on external conditions, especially climatic conditions

[0056] The weighting factor c depending on the external conditions, especially the climatic conditions, makes it possible to take into account weather conditions such as rain, snow, frost and light (day / night), among others.

[0057] In particular, it has been found that drivers tend to slow their vehicles more when visibility is reduced, especially at night, and therefore such modifications allow for a closer approximation of human behavior.

[0058] According to one variant, the velocity can be determined by a velocity function as follows: [Formula 4] V=V legal -(a / W)c where: V legal : Certified maximum speed W: Lane width c: Weighting coefficient depending on external conditions, especially climatic conditions

[0059] According to one variant, the speed may be determined according to a certain amount that is subtracted from the speed of the vehicle before the lane narrowed.

[0060] For example, this fixed amount may be about 5 to 20 km / hour.

[0061] The following explanation regarding the coefficients a and b applies to the various transformations described above.

[0062] The coefficients a and b may be variable and depend, among other things, on the driver of the vehicle.

[0063] The values ​​of the coefficients a and b may be predetermined by feedback-based judgment methods, among others, using driving tests.

[0064] An example of such a feedback-based method for determining the coefficients a and b is described below.

[0065] In a first step, at least two different drivers on at least two roads of different widths drive the same vehicle, for example, three different drivers on three roads of different widths drive the vehicle.

[0066] In a second step, the vehicle speed values ​​obtained for the different drivers are compared with the speed values ​​presented by the vehicle's ACC system.

[0067] In parallel, for each driver the values ​​of lane width and visible lane length provided by the acquisition means 3, in particular the camera, are stored.

[0068] In a third step, the coefficients a and b are derived from three values ​​obtained for each driver corresponding to the three parameters speed, lane width and visible lane length.

[0069] Advantageously, the calculation means 7 may be able to adjust the predetermined coefficients a and / or b.

[0070] According to one variant, the coefficients a and b may not be predetermined, but may be information obtained by the system 1 .

[0071] The system 1 may be able to determine the coefficients a and b by self-learning, which are determined by the system 1 depending, among other things, on the driver's profile.

[0072] Some drivers may have the habit of driving less quickly than most drivers, and such a system could adapt to the driver's usual driving style, which the driver feels is safe.

[0073] Self-learning by the system 1 may be performed in the following manner.

[0074] When the ACC system of the vehicle 100 is not activated, the calculation algorithm of the system 1 stores the values ​​of three parameters: speed, lane width, and visible lane length. From these values, the system 1 may then derive values ​​for the coefficients a and b that correspond to the driver's normal speed profile.

[0075] According to one variant, average speed data over a certain distance, obtained inter alia by statistics, can be used to determine the coefficients a and b.

[0076] According to another variant, high resolution map data can be used to determine the coefficients a and b. Currently, data corresponding to highways is available, with reference to few, if any, smaller roads.

[0077] Advantageously, other parameters may be taken into account in the calculation of the speed of the vehicle by the calculation means 7 .

[0078] According to one variant, self-training of the system 1 by the driver can be used, making it possible to take into account situations where, for example, the driver reduces the speed limit himself compared to the speed allowed by the regulations on a certain type of road, in particular the difference ΔV.

[0079] According to this variant, the velocity may be determined by a velocity function, for example: [Formula 5] V=(V legal -ΔV)-(a / W+b / L)c

[0080] This variant applies to the first of the three variants described above.

[0081] According to one variant, instead of changing the speed, the average speed can be taken into account when passing through a series of curves, which will improve the comfort of the driver and passengers of the vehicle.

[0082] The system 1 may also include means 9 for adjusting the speed. The adjustment means 9 are intended to modify the speed of the vehicle, if necessary, depending on the speed calculated by the calculation means 7.

[0083] The adjusting means 9 may for example comprise at least one actuator, in particular an electric actuator, which may be capable of slowing down the vehicle by acting on the motor and / or the brakes, in particular. The at least one actuator may be controlled by a speed sensor for determining the current speed of the vehicle and by a signal output by the calculating means 7, which provides the speed to be applied.

[0084] If the current speed of the vehicle exceeds the speed provided by the calculation means 7, the adjustment means 9 modifies the speed of the vehicle to be equal to or substantially equal to the speed provided by the calculation means 7.

[0085] Vehicle 100, and in particular system 1, includes all the software and / or hardware elements that are capable of determining the speed control strategy described below.

[0086] These software and / or hardware elements may include software modules.

[0087] The advantage of a system of the type described above lies in the fact that no additional components are required on the vehicle. The information used to calculate the speed is already available, and is used, among other things, to keep the vehicle in its lane or to automatically detect obstacles or other vehicles traveling on the roadway. Information about external conditions, especially climatic conditions, provided, for example, by temperature and / or light sensors, is already available. This leads to a low cost for such a system.

[0088] Another advantage of a system of the type described above lies in the fact that the driver and any passengers of the vehicle feel safe, since such a system makes it possible to manage the speed of the vehicle by replicating human behavior, allowing the speed to be automatically adapted to maintain a level of comfort, reliability and safety in the vehicle.

[0089] Another advantage of a system of the type described above is linked to the fact that it is adaptable to different drivers of the vehicle.

[0090] One way of implementing the method for controlling the speed of a vehicle on a lane equipped with a system 1 of the type described above will now be described with reference to Figure 2. This implementation will be described for a motor vehicle 100.

[0091] In a first step E10, at least one first piece of information relating to the lane is obtained, in particular the lane width information.

[0092] In addition to obtaining first information regarding lane width, it is also possible to obtain information regarding the seen or visible lane length.

[0093] Optionally, in addition to obtaining the first information regarding the lane width, it is also possible to obtain at least one second information regarding the external conditions, in particular the climatic conditions.

[0094] The first acquiring step E10 is carried out for example using acquisition means 3 of the system 1, which for example comprise a camera and / or a map, in particular a digital map, and / or a lidar and / or a temperature sensor and / or a light sensor.

[0095] In a second step E20, the lane width and optionally the visible lane length are determined based on at least one first piece of information about the lane obtained during the preceding obtaining step E10.

[0096] It is also possible to determine the value of the weighting factor c relating to the external conditions, in particular the climatic conditions, on the basis of at least one second piece of information relating to the external conditions obtained during the preceding obtaining step E10.

[0097] The second step E20 is carried out, for example, using the control means 5 of the system 1.

[0098] In a third step E30, a suitable speed for the vehicle is calculated depending on the lane width determined during the second step E20 and, optionally, depending on the visible lane length determined during the second step E20 and / or the external conditions, in particular the climatic conditions.

[0099] The velocity may be determined by a velocity function as follows: [Formula 6] V=V legal -(a / W+b / L) where: V legal : Certified maximum speed W: Lane width L: Visible lane length

[0100] According to a particularly advantageous variant, the speed can be determined by a speed function as follows: [Formula 7] V=V legal -(a / W+b / L)c where: V legal : Certified maximum speed W: Lane width L: Visible lane length c: Weighting coefficient depending on external conditions, especially climatic conditions

[0101] According to one variant, the velocity can be determined by a velocity function as follows: [Formula 8] V=V legal -(a / W)c where: V legal : Certified maximum speed W: Lane width c: Weighting coefficient depending on external conditions, especially climatic conditions

[0102] For various transformations, the coefficients a and b may be predetermined.

[0103] The coefficients a and b may be determined by feedback from tests performed on the vehicle.

[0104] According to one variant, the speed may be determined according to a certain amount that is subtracted from the speed of the vehicle before the lane narrowed.

[0105] The third calculating step E30 is carried out, for example, using the calculating means 7 of the system 1.

[0106] In a fourth step E40, the speed of the vehicle is adjusted according to the speed calculated during step E30.

[0107] If the current speed of the vehicle exceeds the speed calculated during step E30, the speed of the vehicle is corrected to be equal to or substantially equal to the speed calculated during step E30.

[0108] The step E40 of adjusting the fourth speed is carried out, for example, using the adjusting means 9 of the system 1, which for example comprises an actuator.

[0109] One advantage of the above-described type of method lies in the fact that it allows the driver and any passengers of the vehicle to feel safe, since it allows the speed of the vehicle to be managed by replicating human behavior, allowing the speed to be automatically adapted to maintain a level of comfort, reliability, and safety in the vehicle.

[0110] Although the invention has been described above in the context of an automobile, the invention naturally applies to any type of vehicle.

Claims

1. 1. A method for controlling the speed of a vehicle on a lane, comprising: - a step (E10) of obtaining at least one first piece of information about said lane and, optionally, at least one second piece of information about external conditions; - a step (E20) of determining, based on said at least one first piece of information, a lane width and, optionally, a lane length visible to a driver of said vehicle; a step (E30) of calculating a suitable speed for the vehicle depending on the maximum speed authorized on the lane, on the determined lane width, on the determined visible lane length and / or on the external conditions; and a step (E40) of adjusting the speed of the vehicle in response to the calculated speed, During said calculating step (E30), said velocity is calculated as a function V=V ｌｅｇａｌ -(a / W+b / L), where V ｌｅｇａｌ is the maximum speed authorized on the lane, W is the lane width determined during the determining step (E20), L is the visible lane length determined during the determining step (E20), and a and b are predetermined coefficients.

2. During said calculating step (E30), said velocity is calculated as a function V=V ｌｅｇａｌ -(a / W)c, where V ｌｅｇａｌ 2. The method of claim 1, wherein ∇ is the maximum speed authorized on the lane, W is the lane width determined during the determining step (E20), and c is a weighting factor depending on the external conditions.

3. During said calculating step (E30), said velocity is calculated as a function V=V ｌｅｇａｌ -(a / W+b / L)c, where V ｌｅｇａｌ 2. The method of claim 1, wherein ∇ is the maximum speed authorized on the lane, W is the lane width determined during the determining step (E20), L is the visible lane length determined during the determining step (E20), and c is a weighting factor depending on the external conditions.

4. 4. The method according to claim 1, wherein during the obtaining step (E10), the at least one first information about the lane is obtained using a camera and / or a map and / or a lidar.

5. A system (1) for controlling the speed of a vehicle on a lane, comprising: A system (1) comprising software and / or hardware elements (3, 5, 7, 9) for implementing the method according to any one of claims 1 to 4.

6. A motor vehicle (100) comprising a system (1) according to claim 5.

7. A computer program product comprising instructions that, when the program is executed by a computer, cause the program to perform a method according to any one of claims 1 to 4.

8. A computer readable data storage medium having stored thereon a computer program comprising program code instructions for carrying out the method of any one of claims 1 to 4.

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