Method and device for controlling a cruise control system of a vehicle on a roundabout

Abstract

The present invention relates to a method and device for controlling a cruise control system of a vehicle (10) being driven on a portion of road formed by a roundabout (12). To this end, first data, representative of the curvature as a function of the distance on the path (11) taken by the vehicle (10), are received. Second data, representative of a set of points representing maxima of curvature along the path (11) for each portion of the path (11), are determined on the basis of the first data, each of these points being associated with a curvature value and a distance value. A setpoint speed value is determined for each of these points on the basis of the associated curvature value. The cruise control system is controlled on the basis of the determined setpoint speed values.

Description

DESCRIPTION Title: Method and device for controlling a speed regulation system for a vehicle in a roundabout Technical field

[0001] The present invention claims priority from French application 2213598 filed on 16.12.2022, the content of which (text, drawings and claims) is incorporated herein by reference. The present invention relates to methods and devices for controlling a cruise control system of a vehicle, in particular a motor vehicle. The present invention also relates to a method and device for controlling the speed of a vehicle. The present invention also relates to a method and device for controlling a vehicle, in particular an autonomous vehicle. Technological background

[0002] Some contemporary vehicles are equipped with functions or systems or driving assistance, called ADAS (from the English "Advanced Driver-Assistance System" or in French "Advanced Driving Assistance System").

[0003] Among these systems, the cruise control system, for example the adaptive cruise control system, known as ACC (from the English "Adaptive Cruise Control"), has as its primary function the automatic regulation, adaptively for the ACC system, of the speed of the vehicles equipped with it according to their environment. Such an ACC system determines one or more acceleration instructions according to a speed instruction and information relating to the environment of the vehicle, the acceleration instruction(s) being capable of regulating the speed of the vehicle adaptively, that is to say by taking into account the environment of the vehicle.

[0004] The environmental information of a vehicle is obtained, for example, from remote devices, for example via a wireless connection, and / or from sensors embedded in the vehicle, such as radars for example. This information is particularly important for a vehicle, for example to improve the safety of the vehicle by taking into account the environment around it, in particular other vehicles.

[0005] Passenger comfort is another important factor, particularly for the acceptance of vehicle driver assistance systems. For example, excessive acceleration or deceleration can cause discomfort for vehicle passengers, particularly when acceleration is controlled by a cruise control system. Significant and / or repeated accelerations or decelerations are sometimes due to the cruise control system failing to anticipate the target vehicle's behavior.

[0006] Summary of the present invention

[0007] An object of the present invention is to solve at least one of the problems of the technological background described above.

[0008] Another object of the present invention is to improve the regulation of the speed of a vehicle traveling in a roundabout.

[0009] According to a first aspect, the present invention relates to a method for controlling a speed regulation system of a vehicle, the vehicle traveling on a portion of road comprising a roundabout, the method comprising the following steps: - receiving mapping data of the road portion, the mapping data comprising first data representative of curvature as a function of a distance along a path planned for the vehicle according to the road portion; - determining second data representative of a set of points representative of curvature maxima along the path as a function of the first data, a curvature value and a distance value being associated with each point of the set of points; - determination of a set speed value for each point of the set of points as a function of the curvature value associated with each point; - control of a speed regulation system according to the determined set speed values.

[0010] Determining representative points of curvature maxima in the roundabout based on mapping data makes it possible to take these points into account when determining set speeds to regulate the vehicle's speed when crossing the roundabout. This makes it possible, for example, to take a margin by lowering the vehicle's speed according to the phases of crossing the roundabout corresponding to the different maxima, thereby improving the safety of the vehicle and its passengers as well as their comfort in the roundabout.

[0011] According to a variant, a portion of the path associated with the roundabout is formed of 3 consecutive sections with a maximum curvature value for each section and the set of points comprises 4 points, the 3 sections comprising an entry section into the roundabout, an exit section from the roundabout and an intermediate section between the entry section and the exit section, the curvature values ​​associated with the 4 points being determined from the maximum curvature values ​​of at least part of the sections and a determined curvature parameter, the distance values ​​associated with the 4 points being determined from a first distance information item associated with an entry point into the roundabout, a second distance information item associated with a maximum curvature value of the intermediate section and a first and a second determined distance parameter.

[0012] According to another variant, the set of points includes the following 4 consecutive points: - a first point, a first curvature value associated with the first point being determined as corresponding to the maximum between on the one hand the absolute value of the maximum curvature value of the input section and on the other hand the sum of the absolute value of the maximum curvature value of the intermediate section and the determined curvature parameter, a first distance value associated with the first point being determined as corresponding to the first distance information from which the first distance parameter is subtracted; - a second point, a second curvature value associated with the second point being determined as corresponding to the maximum between on the one hand the absolute value of the maximum curvature value of the input section and on the other hand the sum of the absolute value of the maximum curvature value of the intermediate section and the determined curvature parameter, a second distance value associated with the second point being determined as corresponding to a second distance information item associated with the maximum curvature value of the intermediate section from which the second distance parameter is subtracted; - a third point, a third curvature value associated with the third point being determined as corresponding to the absolute value of the maximum curvature value of the intermediate section, a third distance value associated with the third point being determined as corresponding to the second distance information; and - a fourth point, a fourth curvature value associated with the fourth point being determined as corresponding to the absolute value of the maximum curvature value of the intermediate section, a fourth distance value associated with the fourth point corresponding to a determined distance value.

[0013] According to a further variant, the set of points comprises the following 4 consecutive points: - a first point, a first curvature value associated with the first point being determined as corresponding to a sum of the determined curvature parameter and a maximum between the absolute value of the maximum curvature value of the input section, the absolute value of the maximum curvature value of the intermediate section and the absolute value of the maximum curvature value of the output section, a first distance value associated with the first point being determined as corresponding to the first distance information from which the first distance parameter is subtracted; - a second point, a second curvature value associated with the second point being determined as corresponding to the sum of the determined curvature parameter and the maximum between the absolute value of the maximum curvature value of the input section, the absolute value of the maximum curvature value of the intermediate section and the absolute value of the maximum curvature value of the output section, a second distance value associated with the second point being determined as corresponding to the first distance information from which the first distance parameter is subtracted and the second distance parameter added; - a third point, a third curvature value associated with the third point being determined as corresponding to the absolute value of the maximum curvature value of the intermediate section, a third distance value associated with the third point being determined as corresponding to a second distance information associated with the maximum curvature value of the intermediate section; and - a fourth point, a fourth curvature value associated with the fourth point being determined as corresponding to the absolute value of the maximum curvature value of the intermediate section, a fourth distance value associated with the fourth point corresponding to a determined distance value.

[0014] According to a further variant, the first distance parameter is equal to 10 meters, the second distance parameter is equal to 5 meters, the curvature parameter is equal to 0.005 rrr 1and the determined distance value is equal to 2000 m.

[0015] According to an additional variant, the set speed value for each point of the set of points is further determined as a function of a determined lateral acceleration value.

[0016] According to a second aspect, the present invention relates to a device for controlling a cruise control system of a vehicle, the device comprising a memory associated with a processor configured for implementing the steps of the method according to the first aspect of the present invention.

[0017] According to a third aspect, the present invention relates to a vehicle, for example of the automobile type, comprising a device as described above according to the second aspect of the present invention.

[0018] According to a fourth aspect, the present invention relates to a computer program which comprises instructions adapted for executing the steps of the method according to the first aspect of the present invention, in particular when the computer program is executed by at least one processor.

[0019] Such a computer program may use any programming language, and may be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0020] According to a fifth aspect, the present invention relates to a computer-readable recording medium on which is recorded a computer program comprising instructions for carrying out the steps of the method according to the first aspect of the present invention.

[0021] On the one hand, the recording medium can be any entity or device capable of storing the program. For example, the medium may include a storage medium, such as a ROM memory, a CD-ROM or a microelectronic circuit type ROM memory, or a magnetic recording medium or a hard disk.

[0022] Furthermore, this recording medium may also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or hertzian radio or by self-directed laser beam or by other means. The computer program according to the present invention may in particular be downloaded from a network such as the Internet.

[0023] Alternatively, the recording medium may be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to perform or to be used in performing the method in question. Brief description of the figures

[0024] Other characteristics and advantages of the present invention will emerge from the description of the particular and non-limiting exemplary embodiments of the present invention below, with reference to the appended figures 1 to 6, in which:

[0025] [Fig. 1] schematically illustrates an environment comprising a roundabout in which a vehicle is circulating, according to a particular and non-limiting exemplary embodiment of the present invention;

[0026] [Fig. 2] schematically illustrates a diagram representing a curvature profile as a function of the distance for the roundabout of figure 1, according to a first particular and non-limiting exemplary embodiment of the present invention;

[0027] [Fig. 3] schematically illustrates a diagram representing a curvature profile as a function of distance for the roundabout of Figure 1, according to a second particular and non-limiting exemplary embodiment of the present invention;

[0028] [Fig. 4] schematically illustrates a diagram representing a set speed profile for the vehicle of FIG. 1, according to a second particular and non-limiting exemplary embodiment of the present invention;

[0029] [Fig. 5] schematically illustrates a device configured to control a cruise control system of the vehicle of FIG. 1, according to a particular and non-limiting exemplary embodiment of the present invention;

[0030] [Fig. 6] illustrates a flowchart of the different steps of a method for controlling a speed regulation system of the vehicle of FIG. 1, according to a particular and non-limiting exemplary embodiment of the present invention.

[0031] Description of examples of implementation

[0032] A method and a device for controlling a vehicle speed control system will now be described in the following with joint reference to Figures 1 to 6. The same elements are identified with the same reference signs throughout the description which follows.

[0033] According to a particular and non-limiting example of embodiment of the present invention, the control of a cruise control system, such as an ACC system or P-ACC system (from the English "Predictive Adaptive Cruise Control" or in French "predictive adaptive cruise control system"), of a vehicle traveling on a portion of road formed by a roundabout (also called a roundabout or traffic circle) comprises the reception of mapping data relating to the portion of road. This mapping data advantageously comprises first data representative of the curvature as a function of the distance on the path followed by the vehicle to cross the roundabout, the distance corresponding for example to the distance between the position of the vehicle at the time of reception of the data and the point of the path considered.Second data representative of a set of points representing curvature maxima along the path (for example the maximum (or the maximum to which a margin is added) of each portion of the path are determined as a function of the first data, a curvature value and a distance value being associated with each of these points. A set speed value is determined for each of the points of the set as a function of the associated curvature value, for example determined calculation rules or a correspondence table associating curvature values ​​and corresponding speed values. The speed control system is controlled as a function of the previously determined set speed values ​​to control the speed of the vehicle when it crosses the roundabout.

[0034] Figure 1 schematically illustrates an environment 1 in which a vehicle 10 moves, according to a particular and non-limiting exemplary embodiment of the present invention.

[0035] The vehicle 10 corresponds for example to a motor vehicle moving on a portion of road comprising a roundabout 12, the vehicle 10 crossing the roundabout 12 by following a path 11. The path 11 is for example determined using a navigation system on board the vehicle 10 or implemented in the form of a mobile application installed in a mobile communication device, for example example of a smartphone type, connected in wireless communication with the vehicle 10 (for example via Bluetooth® or Wifi®).

[0036] According to other examples, the vehicle 10 corresponds to a coach, a bus, a truck, a utility vehicle or a motorcycle, that is to say to a vehicle of the motorized land vehicle type.

[0037] Vehicle 10 corresponds, for example, to a vehicle traveling in an autonomous or semi-autonomous mode. The vehicle travels, for example, according to a level of autonomy greater than or equal to 2, according to the scale defined by the American federal agency which has established 5 levels of autonomy ranging from 1 to 5, level 0 corresponding to a vehicle having no autonomy, the driving of which is under the total supervision of the driver, level 1 corresponding to a vehicle with a minimal level of autonomy, the driving of which is under the supervision of the driver with minimal assistance from an ADAS system, and level 5 corresponding to a completely autonomous vehicle.

[0038] The vehicle 10 incorporates one or more driving assistance systems, known as ADAS (Advanced Driver-Assistance System). Such ADAS systems are configured to assist, or even replace, the driver of the vehicle 10 in controlling the vehicle 10 on its journey. The vehicle 10 incorporates in particular an automatic speed control system, for example: - an adaptive cruise control system, known as ACC (from the English “Adaptive Cruise Control”); and / or - a predictive cruise control system, known as a PCC system (from the English “Predictive Cruise Control”); and / or - an intelligent speed adaptation system, known as an ISA system (from the English “Intelligent Speed ​​Adaptation”); and / or - a curve speed adaptation system, called the CSA system (from the English “Curve Speed ​​Assist”).

[0039] The examples of ADAS systems in the list above are provided for illustrative purposes and are not limiting, this list is not exhaustive.

[0040] The ADAS systems embedded in the vehicle 10 are for example supplied by data obtained from one or more embedded sensors, such as for example radars, LIDARs and / or cameras, and / or data received from a communication infrastructure.

[0041] According to a particular embodiment, the vehicle 10 carries a communication system configured to communicate with one or more remote devices 102 via a wireless communication network infrastructure. The remote device 102 corresponds for example to a server of the “cloud” 100 (or “cloud” in French). The wireless communication infrastructure comprises for example a set of communication devices 101 of the cellular network antenna type of the LTE 4G or 5G type or of the UBR (Roadside Unit) type.

[0042] The communication system of the vehicle 10 comprises, for example, one or more communication antennas connected to a telematic control unit, called TCU (from the English "Telematic Control Unit"), itself connected to one or more computers of the on-board system of the vehicle 10, in particular one or more computers responsible for controlling the ADAS systems of the vehicle 10. The antenna(s), the TCU unit and the computer(s) form, for example, a multiplexed architecture for the realization of different services useful for the proper functioning of the vehicle and for assisting the driver and / or the passengers of the vehicle in the control of the vehicle 10.The computer(s) and the TCU communicate and exchange data with each other via one or more computer buses, for example a communication bus of the data bus type CAN (from the English "Controller Area Network" or in French "Réseau de contrôles"), CAN FD (from the English "Controller Area Network Flexible Data-Rate" or in French "Réseau de contrôles à débit de données flexible"), FlexRay (according to the ISO 17458 standard) or Ethernet (according to the ISO / IEC 802-3 standard).

[0043] The wireless communication system allowing the exchange of data between the vehicle 10 and the remote device(s) 102 corresponds for example to: - a vehicle-to-infrastructure (V2I) communication system, for example based on the 3GPP LTE-V or IEEE 802.11p standards ITS G5; or - a cellular network type communication system, for example an LTE (Long-Term Evolution), LTE-Advanced, LTE 4G or 5G type network; or - a Wifi type communication system according to IEEE 802.11, for example according to IEEE 802.11 n or IEEE 802.11ac.

[0044] According to another particular example of embodiment, the vehicle 10 carries a receiver of a satellite geolocation system of the GPS type (from the English “Global Positioning System” or in French “Global Positioning System”) or the Galileo system for example in communication with a computer of the on-board system of the vehicle 10.

[0045] Path 11 for example includes 3 portions or sections of paths, for example: - a first section 111 (also called the entry section) corresponding to the portion by which the vehicle 10 enters the roundabout 12, this first section 111 corresponding to a right turn in the direction of travel of the vehicle 10; - a second section 112 (also called intermediate section) corresponding to the portion following the first section 111 in the direction of travel of the vehicle 10, this second section 112 corresponding to a left turn in the direction of travel of the vehicle 10; and - a third section 113 (also called the exit section) corresponding to the portion by which the vehicle 10 exits the roundabout 12, this third section 113 following the second section 112 in the direction of travel of the vehicle 10 and corresponding to a right turn in the direction of travel of the vehicle 10.

[0046] The example in Figure 1 corresponds to an environment 1 in which vehicles travel on the right, as in France for example. The invention also applies to environments in which vehicles travel on the left, as in Great Britain for example, the first section of the path then corresponding to a left turn, the second section to a right turn and the third section to a left turn in such an environment of traffic on the left of the roadway.

[0047] A process for controlling a speed regulation system of the vehicle 10 is advantageously implemented by the vehicle 10, for example by one or more processors of one or more computers on board the vehicle 10.

[0048] In a first operation, map data of the environment 1 are received, for example via a wireless link from the server 101 via the wireless communication infrastructure and the wireless communication system of the vehicle 10.

[0049] This data is for example received as the vehicle 10 moves according to a V2X (Vehicle-to-Everything) communication mode, for example according to an I2V (Infrastructure-to-Vehicle) mode.

[0050] The received mapping data advantageously includes first data representative of the curvature (expressed in rrr 1and corresponding to the inverse of the radius of curvature) on a determined horizon (for example for the 1000, 1500, 2000 or 2500 m in front of the vehicle 10 starting from the position of the vehicle 10 at the time of reception of the mapping data)) and in particular along the path 11 followed by the vehicle 10 to cross the roundabout 12.

[0051] The first data include, for example, for a set of points representative of path 11 (when path 11 is discretized and represented by a plurality of successive points describing path 11): - distance information between the current position of the vehicle 10 (at the time of reception of the mapping data) and the point considered on the path 11, this distance information being expressed in meters (m); and - curvature information at the point considered.

[0052] The first data is for example received in the form of a table such as Table 1 below, with D px representing the distance associated with a point noted PX and C px the curvature associated with this point X.

[0053] [Table 1]

[0072] The mapping data comprising the first intersection data are for example received automatically at regular intervals (for example every 100, 200, 500 ms) or at the request of the vehicle 10. The mapping data are for example received after transmission by the vehicle 10 to the server 101 of current position data of the vehicle 10, for example obtained from the geolocation system on board the vehicle 10.

[0073] The distance between the vehicle 10 and the points of the path 11 is for example updated by the vehicle 10 between two consecutive receptions of the first data, from the dynamic data of the vehicle 10 (for example the speed which makes it possible to determine the distance traveled by measuring the elapsed time) and / or from the position data of the vehicle 10 obtained from the geolocation system on board the vehicle 10.

[0074] In a second operation, second data representative of a set of points 221 to 224 representative of curvature maxima along the path 11 are determined based on the first data obtained in the first operation. A curvature value and a distance value are associated with each point of the set of points.

[0075] Figure 2 and Figure 3 each represent an example of a profile 2, 3 of the curvature as a function of the distance along the path 11 associated with the first data with the points 221 to 224 representative of the curvature maxima obtained.

[0076] Figure 2 thus represents the evolution of the curvature 'C' as a function of the distance 'D', the distance D corresponding to the distance between a position of the vehicle 10 and a point considered on the path 11 following the path 11.

[0077] The curvature profile is represented by a dotted curve 21 plotted in two-dimensional space (D, C) with D corresponding to the abscissa axis and C to the ordinate axis.

[0078] According to the example in Figure 2, the origin of the reference point at D = 0 corresponds to the current position of the vehicle 10 when it arrives at the roundabout 12, at a determined distance (for example equal to 50, 100 or 200 m) from the entrance to the roundabout 12.

[0079] The entry into roundabout 12 along path 11 is represented by a point 211 at a distance DE from vehicle 10 and the exit from roundabout 12 along path 11 is represented by a point 215 at a distance DF from vehicle 10.

[0080] The points 211 and 215 are determined based on the path of the vehicle 10 calculated based on a destination entered into a navigation system. When the vehicle 10 travels through the roundabout 12, the first curvature data received are, for example, updated based on the actual path of the vehicle 10. For example, if the vehicle 10 changes its path and takes a different exit from the roundabout 12 than the one initially planned, new first data are received in real time so that the vehicle 10 has the curvature data corresponding to the actual path followed, which may be different from the path 11 determined by the navigation system based on the final destination of the path of the vehicle 10.

[0081] Curve 21 includes 3 consecutive portions or sections corresponding to the 3 sections 111, 112, 113 of path 11: - a first portion with negative C values, this first portion representing the curvature values ​​associated with the first section 111 of the path 11, this first portion comprising a minimum curvature represented by the point 212 at the distance 'D1' (the curvature value associated with this point 212 being noted C1, the maximum curvature value associated with this first portion corresponding to the absolute value of C1); - a second portion with positive C values, this second portion representing the curvature values ​​associated with the second section 112 of the path 11, this second portion comprising a maximum curvature represented by the point 213 at the distance 'D2' (the curvature value associated with this point 213 being noted C2, the maximum curvature value associated with this second portion corresponding to the value C2); and - a third portion with negative C values, this third portion representing the curvature values ​​associated with the third section 113 of the path 11, this third portion comprising a minimum curvature represented by the point 214 at the distance 'D3' (the curvature value associated with this point 213 being noted C3, the maximum curvature value associated with this third corresponding to the absolute value of C3).

[0082] The set of points representing curvature maxima along the path 11 comprises, for example, 4 points 221 to 224. The curvature values ​​associated with the 4 points 221 to 224 are determined from the maximum curvature values ​​of at least part of the sections 111 to 113 of the path 11 and a determined curvature parameter, noted 'c'.

[0083] The distance values ​​associated with the 4 points 221 to 224 are determined from a first distance information DE associated with the entry point 211 in the roundabout 12, a second distance information D2 associated with a maximum curvature value C2 of the intermediate section 112 and a first and a second parameter, noted 'del' and 'de2', of determined distance.

[0084] The 4 points 221 to 224 make it possible to represent an envelope 22 of the roundabout 12 defined in the reference (D, C) and represented by a solid line connecting the points 221 to 224.

[0085] The first point 221 is followed by the second point 222, itself followed by the third point 223, which is followed by the fourth point 224 according to the direction of travel of vehicle 10 in roundabout 12.

[0086] Each point 221 to 224 is defined in the reference frame (D, C) by a pair of values ​​(distance, curvature). Thus the first point 221 is defined by a first distance value and a first curvature value, the second point 222 is defined by a second distance value and a second curvature value, the third point 223 is defined by a third distance value and a third curvature value and the fourth point 224 is defined by a fourth distance value and a fourth curvature value.

[0087] According to the example of Figure 2, the first curvature value, noted C221 and associated with the first point 221, is determined as corresponding to the maximum between on the one hand the absolute value of the maximum curvature value 'C1' of the inlet section 111 and on the other hand the sum of the absolute value of the maximum curvature value 'C2' of the intermediate section 112 and the determined curvature parameter 'c', i.e.:

[0088] [Math 1]

[0089] C 221 = Max(|Cl|, |C2| + c)

[0090] The first distance value, noted D221 and associated with the first point 221, is determined as corresponding to the first distance information DE from which the first distance parameter 'del' is subtracted, i.e.:

[0091] [Math 2]

[0092] D 221 = DE - del

[0093] The second curvature value, noted C222 and associated with the second point 222, is determined as corresponding to the maximum between on the one hand the absolute value of the maximum curvature value C1 of the first section 111 and on the other hand the sum of the absolute value of the maximum curvature value C2 of the intermediate section 112 and the determined curvature parameter c, i.e.:

[0094] [Math 3]

[0095] C 222 = Max(|Cl|, |C2| + c)

[0096] The second distance value, noted D222 and associated with the second point 222, is determined as corresponding to a second distance information D2 associated with the maximum curvature value C2 of the intermediate section 112 from which the second distance parameter de2 is subtracted, i.e.:

[0097] [Math 4]

[0098] D 222 = D2 - de2

[0099] The third curvature value, denoted C223 associated with the third point 223, is determined as corresponding to the absolute value of the maximum curvature value C2 of the intermediate section 112, i.e. C223 = C2.

[0100] The third distance value, noted D223 and associated with the third point 223, is determined as corresponding to the second distance information D2, i.e. D223 = D2.

[0101] The fourth curvature value, denoted C224 and associated with the fourth point 224, is determined as corresponding to the absolute value of the maximum curvature value C2 of the intermediate section 112, i.e. C224 = C2.

[0102] The fourth distance value, denoted D224 and associated with the fourth point 224, is determined as corresponding to a determined distance value, denoted 'inf' and for example equal to 2000 m, i.e. D224 = inf. According to other examples, the determined distance value 'inf' is equal to 1000, 1500, 2500 or 3000 m.

[0103] According to the example of Figure 3, the first curvature value, noted C221 and associated with the first point 221, is determined as corresponding to a sum of the determined curvature parameter, noted 'c', and a maximum between the absolute value of the maximum curvature value C1 of the inlet section 111, the absolute value of the maximum curvature value C2 of the intermediate section 112 and the absolute value of the maximum curvature value C3 of the outlet section 113, i.e.:

[0104] [Math 5]

[0105] C 221 = Max(|Cl|, |C2|, |C3|) + c

[0106] The first distance value, noted D221 and associated with the first point 221, is determined as corresponding to the first distance information DE from which the first distance parameter 'del' is subtracted, i.e.:

[0107] [Math 6]

[0108] D 221 = DE — del

[0109] The second curvature value, denoted C222 and associated with the second point 222, is determined as corresponding to a sum of the determined curvature parameter, denoted 'c', and a maximum between the absolute value of the maximum curvature value C1 of the inlet section 111, the absolute value of the maximum curvature value C2 of the intermediate section 112 and the absolute value of the maximum curvature value C3 of the output section 113, i.e.:

[0110] [Math 7]

[0111] C 221 = Max(|Cl|, |C2|, |C3|) + c

[0112] The second distance value, denoted D222 and associated with the second point 222, is determined as corresponding to the first distance information DE from which the first distance parameter 'del' is subtracted and the second distance parameter 'de2' is added (the value of 'de2' in the example of figure 3 is equal to or different from the value of 'de2' in the example of figure 2), i.e.:

[0113] [Math 8]

[0114] D 222 = DE - del + de2

[0115] The third curvature value, denoted C223 associated with the third point 223, is determined as corresponding to the absolute value of the maximum curvature value C2 of the intermediate section 112, i.e. C223 = C2.

[0116] The third distance value, noted D223 and associated with the third point 223, is determined as corresponding to the second distance information D2, i.e. D223 = D2.

[0117] The fourth curvature value, denoted C224 and associated with the fourth point 224, is determined as corresponding to the absolute value of the maximum curvature value C2 of the intermediate section 112, i.e. C224 = C2.

[0118] The fourth distance value, denoted D224 and associated with the fourth point 224, is determined as corresponding to a determined distance value, denoted 'inf' and for example equal to 2000 m, i.e. D224 = inf. According to other examples, the determined distance value 'inf' is equal to 1000, 1500, 2500 or 3000 m.

[0119] For example, del = 10 m, de2 = 5 m and c = 0.005 m' 1 . In other examples del is 5 or 15 m, de2 is 3 or 7 m and c is 0.01 or 0.002 m' 1 .

[0120] The number of points representing the curvature maxima is not limited to 4, but is for example equal to 3, 5 or 6 points.

[0121] In a third operation, a set speed value is determined for each point of the set of points 221 to 224 based on the curvature value associated with each point 224.

[0122] The set speed, noted Vcons and expressed in m.s' 1 , is for example also a function of a determined lateral acceleration value, noted aiat, of the vehicle 10. This lateral acceleration value corresponds to a process parameter whose value is fixed and / or adjustable via a human-machine interface. For example, aiat is worth 3 or 4 ms -2 .

[0123] The set speed is for example equal to:

[0124] [Math 9]

[0125] V cons = with c depending on each point 221 to 224 considered.

[0126] The set speed associated with point 221 is a function of C221, the set speed associated with point 222 is a function of C222, the set speed associated with point 223 is a function of C223 and the set speed associated with point 224 is a function of C224.

[0127] In another example, the set speed is also a function of a speed value (in m.s' 1 ) determined, noted £, corresponding to a parameter of the system, the value of which is positive and for example a function of the curvature value associated with the point considered.

[0128] According to this example, the set speed is equal to:

[0129] [Math 10]

[0130] V cons = - s, with c depending on each point 221 to 224 considered.

[0131] In this example, the set speed calculated from aiat and c is reduced by the value of parameter E, which allows a safety margin to be added by reducing the value of the set speed.

[0132] According to yet another example, the value of the set speed associated with each point 221 to 224 is obtained from a LUT (Look-Up Table) type correspondence table. Such a table is for example stored in a memory of the vehicle 10 accessible by the computer implementing the process. Such a table matches each curvature value of a set of curvature values ​​with a single set speed value of a set of set speed values. According to such an example, the LUT table makes it possible for the computer to avoid having to calculate the set speed by making it possible to retrieve the speed value from the LUT table directly, once the curvature value associated with a point 221 to 224 has been determined.

[0133] Figure 4 illustrates a profile 4 of the set speed Vcons (on the ordinate) as a function of the distance D (on the abscissa) obtained from the set speeds determined for each of the points 221 to 224, the origin of the reference (D, Vcons) corresponding for example to the position of the vehicle 10 at the time of reception of the first data or corresponding to a distance value determined with respect to the entry into the roundabout 12.

[0134] According to this illustrative and non-limiting speed profile 4, the set speed decreases from a current value until reaching a minimum speed at the first point 221, before entering the roundabout 12. The set speed stabilizes until the second point 222 (before for example starting the second section 112). Then the set speed to reach the set speed associated with the third point 223 before stabilizing until the fourth point 224.

[0135] In a fourth operation, the speed control system is controlled according to the set speeds determined in the third operation, for example according to profile 4.

[0136] The speed of the vehicle 10 to cross the roundabout 12 is thus automatically regulated by the cruise control system as a function of the curvature along the path 11 and as a function of the position of the vehicle 10 in the roundabout 12. This allows the vehicle 10 to adapt its speed to each roundabout and to the curvatures associated, by minimizing the speed when the curvature radius is high (or the curvature low), improving vehicle safety 10 and passenger comfort.

[0137] Figure 5 schematically illustrates a device 5 configured to control a speed regulation system of a vehicle, for example of the vehicle 10, according to a particular and non-limiting exemplary embodiment of the present invention. The device 5 corresponds for example to a device on board the vehicle 10, for example a computer.

[0138] The device 5 is for example configured for the implementation of the operations described with regard to figures 1 to 4 and / or the steps of the method described with regard to figure 6. Examples of such a device 5 include, but are not limited to, on-board electronic equipment such as an on-board computer of a vehicle, an electronic calculator such as an ECU (“Electronic Control Unit”), a smartphone, a tablet, a laptop. The elements of the device 5, individually or in combination, can be integrated in a single integrated circuit, in several integrated circuits, and / or in discrete components. The device 5 can be produced in the form of electronic circuits or software (or computer) modules or even a combination of electronic circuits and software modules.

[0139] The device 5 comprises one (or more) processor(s) 50 configured to execute instructions for carrying out the steps of the method and / or for executing the instructions of the software(s) embedded in the device 5. The processor 50 may include integrated memory, an input / output interface, and various circuits known to those skilled in the art. The device 5 further comprises at least one memory 51 corresponding for example to a volatile and / or non-volatile memory and / or comprises a memory storage device which may comprise volatile and / or non-volatile memory, such as EEPROM, ROM, PROM, RAM, DRAM, SRAM, flash, magnetic or optical disk.

[0140] The computer code of the embedded software(s) comprising the instructions to be loaded and executed by the processor is for example stored in the memory 51.

[0141] According to various particular and non-limiting embodiments, the device 5 is coupled in communication with other similar devices or systems and / or with communication devices, for example a TCU (from the English “Telematic Control Unit” or in French “Telematic Control Unit”), for example via a communication bus or through dedicated input / output ports.

[0142] According to a particular and non-limiting exemplary embodiment, the device 5 comprises a block 52 of interface elements for communicating with external devices, for example a remote server or the “cloud”. The interface elements of the block 52 comprise one or more of the following interfaces: - RF radio frequency interface, for example Wi-Fi® type (according to IEEE 802.11), for example in the 2.4 or 5 GHz frequency bands, or Bluetooth® type (according to IEEE 802.15.1), in the 2.4 GHz frequency band, or Sigfox type using UBN (Ultra Narrow Band) radio technology, or LoRa in the 868 MHz frequency band, LTE (Long-Term Evolution), LTE-Advanced; - USB interface (from the English “Universal Serial Bus” or “Universal Serial Bus” in French); - HDMI interface (from the English “High Definition Multimedia Interface” or “High Definition Multimedia Interface” in French); - LIN interface (from the English “Local Interconnect Network”).

[0143] According to another particular and non-limiting embodiment, the device 5 comprises a communication interface 53 which makes it possible to establish communication with other devices (such as other computers of the on-board system) via a communication channel 530. The communication interface 53 corresponds for example to a transmitter configured to transmit and receive information and / or data via the communication channel 530. The communication interface 53 corresponds for example to a wired network of the CAN type (from the English “Controller Area Network” or in French “Réseau de contrôles”), CAN FD (from the English “Controller Area Network”) or CAN FD (from the English “Controller Area Network”). Flexible Data-Rate” or in French “Flexible Data Rate Controller Network”), FlexRay (standardized by ISO 17458) or Ethernet (standardized by ISO / IEC 802-3).

[0144] According to a particular and non-limiting exemplary embodiment, the device 5 can provide output signals to one or more external devices, such as a display screen, touch-sensitive or not, one or more speakers and / or other peripherals (projection system) via respective output interfaces. According to a variant, one or other of the external devices is integrated into the device 5.

[0145] Figure 6 illustrates a flowchart of the different steps of a method for controlling a speed regulation system of a vehicle, for example of the vehicle 10, according to a particular and non-limiting exemplary embodiment of the present invention. The method is for example implemented by a device on board the vehicle 10 or by the device 5 of Figure 5.

[0146] In a first step 61, mapping data of the portion of road comprising the roundabout on which the vehicle is traveling are received, the mapping data comprising first data representative of curvature as a function of a distance along a path planned for the vehicle according to the portion of road.

[0147] In a second step 62, second data representative of a set of points representative of curvature maxima along the path are determined based on the first data, a curvature value and a distance value being associated with each point of the set of points.

[0148] In a third step 63, a set speed value is determined for each point of the set of points as a function of the curvature value associated with each point.

[0149] In a fourth step 64, a speed control system is controlled according to the determined set speed values.

[0150] According to a variant, the variants and examples of the operations described in relation to figures 1 to 4 apply to the steps of the method of figure 6.

[0151] Of course, the present invention is not limited to the embodiments described above but extends to a method for determining setpoint speed values ​​as a function of curvature values ​​which would include secondary steps without thereby departing from the scope of the present invention. The same would apply to a device configured for implementing such a method.

[0152] The present invention also relates to a vehicle cruise control system comprising the device 5 of Figure 5.

[0153] The present invention also relates to a vehicle, for example an automobile or more generally an autonomous land-based motor vehicle, comprising the device 5 of FIG. 5 or the speed regulation system above.

Claims

CLAIMS 1. Method for controlling a speed regulation system of a vehicle (10), said vehicle traveling on a portion of road comprising a roundabout (12), said method comprising the following steps: - receiving (61) mapping data of said portion of road, said mapping data comprising first data representative of curvature as a function of a distance along a path (11) provided for said vehicle (10) along said portion of road; - determination (62) of second data representative of a set of points (221 to 224) representative of curvature maxima along said path (11) as a function of said first data, a curvature value and a distance value being associated with each point of said set of points (221 to 224); - determination (63) of a set speed value for each point of said set of points (221 to 224) as a function of said curvature value associated with said each point; - control (64) of said speed regulation system as a function of the determined set speed values.

2. Method according to claim 1, for which a portion of said path (11) associated with said roundabout (12) is formed of 3 consecutive sections (111, 112, 113) with a maximum curvature value for each section and said set of points comprises 4 points (221 to 224), said 3 sections comprising an entry section (111) in said roundabout (12), an exit section (113) of said roundabout (12) and an intermediate section (112) between said entry section (111) and said exit section (113), the curvature values ​​associated with said 4 points (221 to 224) being determined from the maximum curvature values ​​of at least a part of said sections (111 to 113) and a determined curvature parameter, the distance ... to 224) being determined from first distance information associated with an entry point (211) in said roundabout (12),of a second distance information associated with a value, maximum curvature of said intermediate section (112) and a first and a second determined distance parameters.

3. Method according to claim 2, for which said set of points comprises the following 4 consecutive points: - a first point (221), a first curvature value associated with said first point (221) being determined as corresponding to the maximum between on the one hand the absolute value of the maximum curvature value of said input section (111) and on the other hand the sum of the absolute value of the maximum curvature value of said intermediate section (112) and said determined curvature parameter, a first distance value associated with said first point (221) being determined as corresponding to said first distance information from which said first distance parameter is subtracted; - a second point (222), a second curvature value associated with said second point (222) being determined as corresponding to the maximum between on the one hand the absolute value of the maximum curvature value of said input section (111) and on the other hand the sum of the absolute value of the maximum curvature value of said intermediate section (112) and said determined curvature parameter, a second distance value associated with said second point being determined as corresponding to a second distance information item associated with the maximum curvature value of said intermediate section (112) from which said second distance parameter is subtracted; - a third point (223), a third curvature value associated with said third point (223) being determined as corresponding to the absolute value of the maximum curvature value of said intermediate section (112), a third distance value associated with said third point (223) being determined as corresponding to said second distance information; and - a fourth point (224), a fourth curvature value associated with said fourth point (224) being determined as corresponding to the absolute value of the maximum curvature value of said intermediate section (112), a fourth distance value associated with said fourth point (224) corresponding to a determined distance value. Tl 4. Method according to claim 2, for which said set of points comprises the following 4 consecutive points: - a first point (221), a first curvature value associated with said first point (221) being determined as corresponding to a sum of said determined curvature parameter and a maximum between the absolute value of the maximum curvature value of said input section (111), the absolute value of the maximum curvature value of said intermediate section (112) and the absolute value of the maximum curvature value of said output section (113), a first distance value associated with said first point being determined as corresponding to said first distance information from which said first distance parameter is subtracted; - a second point (222), a second curvature value associated with said second point (222) being determined as corresponding to the sum of said determined curvature parameter and the maximum between the absolute value of the maximum curvature value of said input section (111), the absolute value of the maximum curvature value of said intermediate section (112) and the absolute value of the maximum curvature value of said output section (113), a second distance value associated with said second point being determined as corresponding to said first distance information from which said first distance parameter is subtracted and said second distance parameter is added; - a third point (223), a third curvature value associated with said third point (223) being determined as corresponding to the absolute value of the maximum curvature value of said intermediate section (112), a third distance value associated with said third point (223) being determined as corresponding to a second distance information item associated with the maximum curvature value of said intermediate section; and - a fourth point (224), a fourth curvature value associated with said fourth point (224) being determined as corresponding to the absolute value of the maximum curvature value of said intermediate section (112), a fourth distance value associated with said fourth point (224) corresponding to a determined distance value.

5. Method according to claim 3 or 4, for which said first distance parameter is equal to 10 meters, said second distance parameter is equal to 5 meters, said curvature parameter is equal to 0.005 rrr 1 and said determined distance value is equal to 2000 m.

6. Method according to one of claims 1 to 5, for which said set speed value for each point of said set of points (221 to 224) is further determined as a function of a determined lateral acceleration value.

7. Computer program comprising instructions for implementing the method according to any one of the preceding claims, when these instructions are executed by a processor.

8. Computer-readable recording medium on which is recorded a computer program comprising instructions for carrying out the steps of the method according to one of claims 1 to 6.

9. Device (5) for controlling a speed regulation system of a vehicle, said device (5) comprising a memory (51) associated with at least one processor (50) configured for implementing the steps of the method according to any one of claims 1 to 6.

10. Vehicle (10) comprising the device (5) according to claim 9.

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