METHOD AND DEVICE FOR CONTROLLING A VEHICLE'S VEHICLE APPROACHING A TRAFFIC SIGNAL

Abstract

The present invention relates to a method and device for controlling a cruise control system of a vehicle. According to the invention, a signalling element (110) is detected. The cruise control system of the vehicle is regulated according to a speed regulation profile comprising one or more deceleration phases (21, 22) followed by a phase (23) of approaching the signalling element (110) at a constant target speed throughout the approach phase (23), which constant target speed is dependent on the signalling element (110). The start of each time period is dependent on a comparison between a target deceleration associated with each deceleration phase (21, 22) and a current deceleration dependent on a current speed of the vehicle, on the target speed, on a current distance between the vehicle and the signalling element (110) and on the duration of the approach phase (23).

Description

[0001] DESCRIPTION

[0002] Title: Method and device for controlling a speed regulation system for a vehicle approaching a road sign

[0003] The present invention claims priority from French application 2204821 filed on 20.05.2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0004] Technical field

[0005] 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 acceleration and / or speed of a vehicle. The present invention also relates to a method and device for controlling a vehicle, in particular an autonomous vehicle.

[0006] Technological background

[0007] 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").

[0008] Among these systems, the cruise control system or 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 vehicles equipped with it according to their environment.

[0009] The cruise control system determines one or more acceleration instructions to reach a set speed, for example set by the vehicle driver.

[0010] The ACC system determines one or more acceleration instructions based on a speed instruction and information relating to the vehicle's environment, the acceleration instruction(s) being capable of regulating the vehicle's speed adaptively, i.e. taking into account the vehicle's environment.

[0011] This environmental information corresponds, for example, to the distance between the vehicle equipped with the ACC system and a vehicle traveling in front, to the speed (for example relative) of the vehicle traveling in front, to the acceleration of the vehicle traveling in front and / or to a regulatory speed limit.

[0012] According to another example, this environmental information corresponds to information relating to road signage elements, for example traffic signs and / or traffic lights. This information corresponds for example to the states taken by a traffic light (state corresponding to a red light or state corresponding to a green light) and is for example received by the vehicle from the traffic light or a network infrastructure via a wireless connection, these objects (the vehicle and the traffic light) being said to be connected.

[0013] Managing signaling elements for controlling a speed regulation system requires the presence of a wireless network infrastructure and communication devices integrated into the signaling elements and vehicles. Such elements are expensive, which in particular generates additional vehicle manufacturing costs.

[0014] Furthermore, not all life situations encountered by a vehicle are anticipated or managed by existing systems, which can lead to safety issues for the vehicle and its passengers.

[0015] Summary of the present invention

[0016] An object of the present invention is to solve at least one of the problems of the technological background described above.

[0017] Another object of the present invention is to improve the control of a cruise control system on board a vehicle.

[0018] 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 approaching a signaling element, the method comprising the following steps:

[0019] - detection of the signaling element at a first time instant;

[0020] - determining a first time interval associated with a first phase of a vehicle speed regulation profile, a second time interval associated with a second phase of the profile, the second phase temporally following the first phase, and determining a target speed of the vehicle as a function of the detected signaling element, the target speed being associated with a third phase of the profile, the third phase temporally following the second phase, the third phase having a determined duration, a start of the first time interval being determined as a function of a result of a comparison between a first target deceleration value associated with the first phase and a current deceleration value determined as a function of a current speed of the vehicle, the target speed, a current distance between the vehicle and the signaling element and the determined duration of the third phase,and a start of the second time interval being determined based on a result of a comparison between a second target deceleration value associated with the second phase and the current deceleration value, the second target deceleration value being less than or equal to the first target deceleration value;,

[0021] - control of the cruise control system according to the cruise control profile.

[0022] Such a method makes it possible to improve the control of the vehicle's speed control system by determining a control profile comprising one or more deceleration phases followed by a constant speed phase, which depends on the detected signaling element. Such a method only requires means configured to detect the signaling element (for example an on-board camera and / or road map information) as well as the distance between the vehicle and this signaling element, without needing to receive data from the signaling element.

[0023] The deceleration phase(s) reproduce a classic approach of a driver approaching a signal element, the target speed associated with the last phase being for example provided to give the driver the opportunity to manually act on the control of the vehicle if necessary, which increases the safety of the vehicle and its passengers.

[0024] According to a variant, the start of the first time interval is equal to a second time instant corresponding to, when the vehicle is at a distance less than a determined distance from the signaling element, the time instant at which the current deceleration value reaches the first target deceleration value, and the start of the second time interval is equal to a third time instant corresponding to the time instant at which the current deceleration value reaches the second target deceleration value.

[0025] According to another variant, the current deceleration value, noted d n , is determined according to the following equation: dn = (Vtarget 2 - V 2 ) / (2 * (D - X * Vcible)) with Vcibie corresponding to said target speed, V corresponding to the current speed of said vehicle, D corresponding to the current distance between the vehicle and the signaling element and X corresponding to the determined duration of the third phase.

[0026] According to a further variant, the signaling element belongs to a set of signaling elements comprising:

[0027] - a STOP sign;

[0028] - a YIELD sign;

[0029] - a red traffic light; and

[0030] - a green traffic light.

[0031] According to a further variant, the target speed is 25 km / h when the signal element corresponds to the YIELD sign, the target speed is 30 km / h when the signal element corresponds to the STOP sign or the red traffic light and the target speed is 50 km / h when the signal element corresponds to the green traffic light. According to an additional variant, the determined duration of the third phase is 5 seconds, the first target deceleration value is -0.3 ms -2 and the second target deceleration value is -0.7 ms -2 or -1.2 ms' 2 .

[0032] According to a further variant, the profile further comprises a fourth phase between the second phase and the third phase when a speed of the vehicle reaches a value lower than the target speed before the start of the third phase, an acceleration value being associated with the fourth phase, the acceleration value being determined so that a speed of the vehicle at the end of the fourth phase is equal to the target speed.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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. On the one hand, the recording medium may be any entity or device capable of storing the program. For example, the medium may comprise a storage means, such as a ROM memory, a CD-ROM or a microelectronic circuit type ROM memory, or a magnetic recording means or a hard disk.

[0038] 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.

[0039] 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.

[0040] Brief description of the figures

[0041] 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 4, in which:

[0042] [Fig. 1] schematically illustrates an environment of a vehicle, according to a particular and non-limiting exemplary embodiment of the present invention;

[0043] [Fig. 2] illustrates a diagram representing a cruise control profile for controlling a cruise control system of the vehicle of Fig. 1, according to a particular and non-limiting exemplary embodiment of the present invention;

[0044] [Fig. 3] 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;

[0045] [Fig. 4] 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. Description of the exemplary embodiments

[0046] 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 4. The same elements are identified with the same reference signs throughout the description which follows.

[0047] According to a particular and non-limiting example of embodiment of the present invention, the control of a vehicle speed control system, for example an ACC system, comprises the detection of a signaling element positioned on the edge of a road on which the vehicle is traveling. Such a signaling element corresponds to a traffic sign or a traffic light intended to regulate the passage of vehicles at a crossroads for example. The vehicle speed control system is advantageously regulated according to a speed control profile comprising one or more deceleration phases (negative acceleration of the vehicle) followed by a phase of approach to the signaling element (of a determined duration) during which the speed is regulated to comply with a target speed which is a function of the detected signaling element.The deceleration phase(s) are each associated with a time interval of a determined duration. The duration of each time interval is determined by determining the start of each time interval, which is a function of a result of a comparison between a target deceleration value associated with the considered deceleration phase of the profile and a current deceleration value determined as a function of a current speed of the vehicle, the target speed, a current distance between the vehicle and the signaling element and the duration of the approach phase.

[0048] Figure 1 schematically illustrates an environment 1 of a vehicle 10, according to a particular and non-limiting exemplary embodiment of the present invention.

[0049] Figure 1 illustrates a vehicle 10, for example a motor vehicle, carrying for example means configured to detect the presence of a signaling element 110 arranged along the traffic lane 101 taken by the vehicle 10, in front of the vehicle 10 according to the direction of travel of the vehicle 10. 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.

[0050] Vehicle 10 corresponds to a vehicle traveling under the full supervision of a driver or traveling in an autonomous or semi-autonomous mode. The vehicle travels according to a level of autonomy equal to 0 or according to a level of autonomy ranging from 1 to 5 for example, 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 full 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.

[0051] According to the example of Figure 1, the vehicle 10 travels on a portion of road comprising a first traffic lane 101 on which the vehicle 10 travels. The first traffic lane 101 crosses a second traffic lane, the passage at the intersection between these two traffic lanes being regulated by the signaling element 110.

[0052] The environment of the vehicle 10 is not limited to the example of FIG. 1 but extends to any road environment comprising a road on which the vehicle 10 is traveling, the passage or crossing of a portion of which is regulated by a signaling element. Such a portion corresponds for example to a crossroads, a road intersection, a roundabout, a level crossing, etc.

[0053] The signaling element 110 corresponds, for example, to one of the following elements:

[0054] - a STOP sign requiring the vehicle to stop 10;

[0055] - a YIELD sign requiring the vehicle to stop if necessary;

[0056] - a three-color traffic light taking a first state corresponding to the green light (passage of the light authorized for the vehicle 10) and a second state corresponding to the red light (stop required for the vehicle 10). The vehicle 10 for example carries one or more of the following means of detecting the signaling element:

[0057] - one or more cameras (associated or not with a depth sensor) for the acquisition of one or more images of the environment around the vehicle 10 located in the field of vision of the camera(s); and / or

[0058] - a navigation system and / or a geolocation system comprising road map information of the road environment in which the vehicle 10 is traveling, the map information comprising information on the presence and position of the signaling elements.

[0059] According to an alternative embodiment, the vehicle 10 also carries one or more of the following devices or systems:

[0060] - one or more millimeter wave radars arranged on the vehicle 10, for example at the front, at the rear, on each front / rear corner of the vehicle; each radar is adapted to emit electromagnetic waves and to receive the echoes of these waves returned by one or more objects (for example a vehicle traveling in front of the vehicle 10 or the signaling element 110), for the purpose of detecting obstacles and their distances from the vehicle 10; and / or

[0061] - one or more LIDAR(s) (from the English “Light Detection And Ranging”, or

[0062] “Light detection and distance estimation” in French), a LIDAR sensor corresponding to an optoelectronic system composed of a laser emitting device, a receiving device comprising a light collector (to collect the part of the light radiation emitted by the emitter and reflected by any object located in the path of the light rays emitted by the emitter) and a photodetector which transforms the collected light into an electrical signal; a LIDAR sensor thus makes it possible to detect the presence of objects (for example a vehicle traveling in front of the vehicle 10 or the signaling element 110) located in the emitted light beam and to measure the distance between the sensor and each detected object; and / or

[0063] - a receiver of a satellite geolocation system configured to determine the current position of the vehicle 10, for example a GPS type system (from the English

[0064] "Global Positioning System" or Galileo; the current position is for example expressed in the form of coordinates, for example in the form of a latitude / longitude pair.

[0065] The data acquired by the on-board sensor(s) feeds, for example, one or more driving assistance systems, known as ADAS (Advanced Driver Assistance System) on board the vehicle 10. Such an ADAS system is configured to assist, or even replace, the driver of the vehicle 10 in controlling the vehicle 10 on its journey.

[0066] According to a first example, the vehicle 10 has an ADAS system corresponding to an automatic speed regulation system, called a CC system (from the English “Cruise Control”). Such a system is intended to automatically stabilize the speed of the vehicle around a set speed set by the driver of the vehicle 10, for example via a control lever arranged near the steering wheel, without the driver having to press the accelerator pedal. The CC system manages the speed by determining or calculating set acceleration values ​​evolving over time as a function of the current speed of the vehicle (for example obtained from a speed sensor on board the vehicle 10, for example an odometer) and as a function of the set speed. Thus, the data obtained from the speed sensor(s) on board the vehicle 10 allow the CC system of the vehicle 10 to establish a longitudinal acceleration setpoint A con sign(t).

[0067] According to a second example, the vehicle 10 has an ADAS system corresponding to an adaptive speed regulation system, called ACC system. When the ACC system is activated, the ACC system aims to achieve a set acceleration, called A con sign(t), which varies over time 't' and which makes it possible to maintain or reach a regulation speed. The ACC system or a computer of this system transmits for example the acceleration instructions Aconsigne(t) that it has determined to the computer(s) supervising the operation of a powertrain of the vehicle 10, in particular so that the latter determine(s) the torque instructions to be generated by the powertrain to comply with the acceleration instructions A consign(t) and regulate the longitudinal speed of the vehicle 10. According to a third example, the vehicle 10 has both a CC system and an ACC system or a single system on board the vehicle 10 implements the CC function and the ACC function.

[0068] A process for controlling a speed regulation system, for example an ACC system, of the vehicle 10 is advantageously implemented by the vehicle 10, that is to say by a computer or a combination of computers of the on-board system of the vehicle 10, for example by the computer(s) responsible for controlling the ACC system.

[0069] The control of the speed regulation system according to the present invention is based on a determined speed regulation profile, such a profile advantageously comprising one or more successive deceleration phases (with for each of these phases a determined negative setpoint acceleration, a negative acceleration corresponding to a deceleration) followed by a constant speed phase. The speed regulation system is thus controlled according to setpoint deceleration values ​​each associated with a deceleration phase of the profile and a setpoint speed associated with the last constant speed phase.

[0070] An example of such a speed regulation profile is illustrated in Figure 2, according to a particular and non-limiting embodiment of the present invention.

[0071] Diagram 2 of Figure 2 illustrates a profile of the speed denoted 'V' (on the ordinate of the diagram, expressed in m / s) as a function of the time denoted 't' (expressed in seconds, denoted 's'). According to a variant, diagram 2 illustrates in an equivalent manner the speed V as a function of the distance (expressed in m), the relationship between the time 't' and the distance 'd' being known and a function of the speed (and acceleration) of the vehicle 10.

[0072] According to the particular example in Figure 2, the speed regulation profile includes 3 phases, namely:

[0073] - a first deceleration phase 21, a first target deceleration value, note dphaseï being associated with this first phase 21 and being for example equal to -0.3 m.s' 2 (according to other examples dphaseï is -0.2, -0.4 or -0.5 m.s' 2); dphaseï corresponds for example to the set acceleration value supplied to the speed regulation system to control the latter during the first deceleration phase 21; the first deceleration phase begins at a time t1 (after a time t0 corresponding to the time of detection of the signaling element 210) and ends at a time t2, the first time interval between t1 and t2 being associated with the first deceleration phase 21 and corresponding to the duration of the first deceleration phase 21;

[0074] - a second deceleration phase 22, a second target deceleration value, note d P hase2 being associated with this second phase 22 and being for example equal to -0.7 m.s' 2 or -1.2 m.s' 2 (according to other examples of P hase2 takes any value between -0.7 and -1.2 m.s' 2 ) ; d Phase2 corresponds for example to the set acceleration value supplied to the speed regulation system to control the latter during the second deceleration phase 22; the second deceleration phase 22 begins at time t2 and ends at time t3, the second time interval between t2 and t3 being associated with the second deceleration phase 22 and corresponding to the duration of the second deceleration phase 22; and

[0075] - a third phase 23, a constant speed value called target speed Vcibie being associated with this third phase and being a function of the type of the signaling element 210 detected; Vcibie corresponds for example to the set speed supplied to the speed control system to control the latter during the third phase 23; the third phase 23 begins at time t3 and ends at time t4, t4 corresponding to the time at which the vehicle 10 reaches the signaling element 210; the third time interval associated with the third phase and between t3 and t4 has a determined duration, noted 'X', X being for example equal to 5 s (according to other examples, X is 4, 6, 8 or 10 s); X corresponds for example to a parameter of the speed control system whose value can be modified, for example via an HMI (human-machine interface) accessible by a user of the vehicle 10.

[0076] The operations of the control process of the vehicle speed control system 10 described below are implemented sequentially or simultaneously. For example, some of the operations described below, even if described in the form of different unit operations, are implemented in parallel and may form a single operation. In a first operation, the signaling element 210 is detected by the vehicle 10 at a first time instant t0.

[0077] The signaling element 210 corresponds for example to one of the following 4 elements:

[0078] - a STOP sign;

[0079] - a YIELD sign;

[0080] - a red traffic light; and

[0081] - a green traffic light.

[0082] The signaling element 210 is for example detected by applying one or more image processing methods to image data of the environment of the vehicle 10 received from a camera on board the vehicle.

[0083] An object recognition method is for example applied to the received image data to detect the presence of the signaling element 210 and recognize the type of the signaling element. The image processing method implemented corresponds for example to a method called automatic learning or machine learning, for example implemented by a neural network.

[0084] The distance separating the vehicle 10 from the signaling element 210 at time t0 is for example determined from the received image data. According to a variant, this distance is determined from data received from an object detection sensor (for example a radar or a LIDAR) on board the vehicle 10.

[0085] According to another example, the signaling element 210 and the distance separating this element 210 from the vehicle 10 at the instant of detection are determined from map data accessible by the vehicle 10, this data being for example stored in a memory of the vehicle 10. This map data corresponds for example to map data of a navigation system of the vehicle 10, the detection of the element 210 and the determination of the distance being obtained by knowing the geographical position of the vehicle 10 (obtained for example via a GPS type geolocation system). In a second operation, the target speed Vcibie associated with the third phase 23 of the speed regulation profile is determined according to the type of the signaling element detected.

[0086] For example, the target speed Vcibie is 25 km / h (or approximately 7 ms' 1) when signaling element 210 corresponds to the YIELD sign, the target speed is 30 km / h (i.e. approximately 8.3 ms' 1 ) when the signaling element corresponds to the STOP sign or the red traffic light and the target speed is 50 km / h (i.e. approximately 14 ms' 1 ) when the signaling element corresponds to the green traffic light.

[0087] Of course, these speed values ​​are given as examples and are not exhaustive. According to other examples, Vcibie is worth 20 or 30 km / h for a YIELD sign, Vcibie is worth 35 or 40 km / h for a STOP sign or a red traffic light and Vcibie is worth 40 or 45 km / h for a green traffic light.

[0088] The target value is for example selected from a look-up table, called LUT (from the English “Look-Up Table”) stored in a memory accessible by the computer implementing the process, such a LUT matching a Vcibie value for each type of signaling element.

[0089] In a third operation, the first time interval associated with the first phase 21 of the vehicle speed regulation profile and the second time interval associated with the second phase 22 of the profile are determined.

[0090] For this purpose, the time instant t1 corresponding to the start of the first phase 21 and the time instant t2 corresponding to the start of the second phase 22 are determined. The time instant t3 corresponding to the end of the second time interval is determined from the value X of the duration of the third phase which corresponds to a determined parameter of the system, for example equal to 5 s. This parameter corresponds for example to a fixed distance relative to the location of the detected signaling element 210. This distance corresponds for example to the parameter of the system stored in memory, the value of X being deduced from this distance once Vcibie has been determined. The time instant t1 is for example determined by comparing the first target deceleration value dphaseï associated with the first phase 21 and a current deceleration value, noted 'd n', determined as a function of a current speed, noted 'V', of the vehicle, the target speed Vcibie, a current distance, noted 'D', between the vehicle 10 and the signaling element 210 and the duration X determined for the third phase.

[0091] Thus, once the signaling element 210 is detected, n is calculated as the vehicle 10 moves, for example at regular intervals (for example every 10, 20, 50 or 100 ms), and compared to dphaseï .

[0092] The current deceleration value d n is for example obtained from the following equation:

[0093] [Math 1]

[0094] A value is said to be current when it is determined at a current time. When n is determined at regular intervals, the current value of d n corresponds to the value of d nat the time it is calculated, the current speed of the vehicle used to calculate n corresponding to the value of the vehicle speed at the instant at which d n is calculated.

[0095] When the signaling element 210 is detected at tO, the calculation of d n is triggered. According to a variant, the calculation of dn is triggered provided that the distance separating the vehicle 10 from the signaling element is less than a threshold distance, for example less than 160 m, or, according to other examples, less than 250, 200 or 150 m. According to a variant, this threshold distance depends on the speed of the vehicle 10 at the instant t0 of detection of the element 210 and the determined target speed Vcibie.

[0096] The start t1 of the first time interval is thus, for example, determined when the following two conditions are met:

[0097] - the distance between the vehicle 10 and the element 210 is less than the threshold distance;

[0098] ■ dphaseï — dn- In other words, t1 corresponds to the time instant at which d n reaches dphaseï , provided that at t1 the distance between the vehicle 10 and the element 210 is less than the threshold distance.

[0099] According to the equation of dn above, considering that the current speed of the vehicle 10 is constant (i.e. with variations around an average speed lower than a threshold, for example lower than 2 or 5% of the average speed) from t0, the value of dn will decrease (considering that Vcibie is lower than the current speed of the vehicle 10) as the vehicle 10 approaches the signaling element 210.

[0100] By expressing the deceleration of n with a negative value, then the deceleration of ndecreases as the distance between the vehicle 10 and the element 210 increases. By expressing the deceleration d n with a positive value (which is equivalent to using a notion of negative acceleration to define deceleration), then the deceleration of n increases as the distance between the vehicle 10 and the element 210 increases.

[0101] In the rest of the description, deceleration is expressed with a negative value, this value decreasing as deceleration increases.

[0102] When the first phase 21 begins (at t1), the first target deceleration value dphaseï becomes the set acceleration supplied to the cruise control system of the vehicle 10, for example the ACC system. The speed of the vehicle 10 then decreases in this first phase according to the first target deceleration value dphaseï.

[0103] The start t2 of the second phase 22 (which corresponds to the end of the first phase) is determined by comparing the second target deceleration value d P hase2 associated with the second phase 22 to dn which is for example calculated according to the equation above. t2 thus corresponds for example to the time instant at which d n reached P hase2, that is to say when the following condition is met: d P hase2 d n .

[0104] A speed control profile according to the example of Figure 2 with a first phase of gentle deceleration followed by a second phase of stronger deceleration (i.e. with a first target deceleration value dphaseï, which is for example equal to -0.3 m.s' 2 , greater than the first target deceleration value d P hase2, which is for example equal to -0.7 ms -2 ) has several advantages, namely:

[0105] - the first deceleration phase 21 makes it possible to alert the driver of the vehicle 10 that a signaling element 210 has been detected, with a low or gentle deceleration;

[0106] - the second deceleration phase 22 with a greater or more marked deceleration makes it possible to reach the target speed Vcibie of the third phase more quickly and also makes it possible to make the driver feel the difference with the third phase 23 during which the speed of the vehicle 10 will be maintained and regulated around Vcibie; and

[0107] - the third phase 23 with a determined duration (or a determined travel distance) and with a target speed adapted to the detected signaling element 210 gives the driver the opportunity to regain full control of the vehicle 10 if necessary, by deactivating the speed control system. For example, if the signaling element 210 corresponded to a green light at t0 and it turns red during the third phase 23, the driver must take control of the vehicle to stop the vehicle 10 and mark the stop at the red light. According to another example, in the case of a YIELD sign, if a vehicle arrives on road 102, the vehicle 10 must mark the stop at the sign.Similarly, in the case of a STOP sign or a red light, a moderate or low target speed allows the driver time to regain control of the vehicle 10 during the third phase 23 to stop the vehicle 10 and mark the stop at the sign or light; if the red light changes back to green during the third phase 23, or during one of the deceleration phases, the driver can then decide to let the cruise control system regulate the speed of the vehicle 10 until it passes the signaling element 210.

[0108] According to particular embodiments, the number of deceleration phases 21, 22 can vary according to the speed of the vehicle 10 at the instant t0 of detection of the signaling element 210.

[0109] For example, when the speed of the vehicle 10 is lower than a threshold at time t0, the profile comprises only one deceleration phase, that is to say that the first phase 21 and the second phase 22 form only one phase with the same target deceleration value which corresponds for example to the first target deceleration value dphaseï or to another value. The deceleration value of this single phase depends on the speed of the vehicle at t0 and the target speed Vcibie depending on the type of the signaling element detected.

[0110] According to another example, when the speed of the vehicle 10 is greater than a threshold (for example greater than 90, 100 or 110 km / h) at time t0, the profile comprises only a single deceleration phase, that is to say that the first phase 21 and the second phase 22 form only a single phase with the same target deceleration value which corresponds for example to the second target deceleration value dphaseï or to another value for example lower than this value (that is to say for a greater deceleration). The deceleration value of this single phase depends on the speed of the vehicle at t0 and the target speed Vcibie depending on the type of the signaling element detected.

[0111] According to another particular embodiment, the profile further comprises a fourth phase between the second phase 22 and the third phase 23 when the speed of the vehicle 10 reaches before the end of the second phase a value lower than the target speed Vcibie.

[0112] According to this embodiment, an acceleration value (positive value) is for example associated with the fourth phase, the acceleration value being determined so that a speed of the vehicle at the end of the fourth phase is equal to the target speed Vcibie.

[0113] According to another embodiment, when the speed of the vehicle 10 reaches at the end of the second phase 22, that is to say at time t3, a speed having a value lower than the target speed Vcibie, the value of the speed associated with the third phase 23 becomes this speed of value lower than Vcibie.

[0114] In a fourth operation, the cruise control system of the vehicle 10 is controlled according to the cruise control profile determined in the previous operations. The set acceleration values ​​of the control system correspond to the target deceleration values ​​d P hasei and d P hase2 associated with each deceleration phase 21, 22 and the set speed of the regulation system for the third phase 23 at constant speed corresponds to Vcibie (or to the modified target speed if applicable).

[0115] Figure 3 schematically illustrates a device 3 configured to control a vehicle speed regulation system, for example of the vehicle 10, according to a particular and non-limiting exemplary embodiment of the present invention. The device 3 corresponds for example to a device on board the vehicle 10, for example a computer.

[0116] The device 3 is for example configured for the implementation of the operations described with regard to figures 1 and 2 and / or the steps of the method described with regard to figure 4. Examples of such a device 3 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 3, individually or in combination, can be integrated in a single integrated circuit, in several integrated circuits, and / or in discrete components. The device 3 can be produced in the form of electronic circuits or software (or computer) modules or even a combination of electronic circuits and software modules.

[0117] The device 3 comprises one (or more) processor(s) 30 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 3. The processor 30 may include integrated memory, an input / output interface, and various circuits known to those skilled in the art. The device 3 further comprises at least one memory 31 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.

[0118] 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 31. According to various particular and non-limiting exemplary embodiments, the device 3 is coupled in communication with other similar devices or systems (for example other computers) 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.

[0119] According to a particular and non-limiting exemplary embodiment, the device 3 comprises a block 32 of interface elements for communicating with external devices. The interface elements of the block 32 comprise one or more of the following interfaces:

[0120] - 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;

[0121] - USB interface (from the English “Universal Serial Bus” or “Universal Serial Bus” in French);

[0122] - HDMI interface (from the English “High Definition Multimedia Interface” or “High Definition Multimedia Interface” in French);

[0123] - LIN interface (from the English “Local Interconnect Network”).

[0124] According to another particular and non-limiting exemplary embodiment, the device 3 comprises a communication interface 33 which makes it possible to establish communication with other devices (such as other computers of the on-board system) via a communication channel 330. The communication interface 33 corresponds for example to a transmitter configured to transmit and receive information and / or data via the communication channel 330. The communication interface 33 corresponds for example to a wired network of the CAN (Controller Area Network) type, CAN FD (Controller Area Network Flexible Data-Rate), FlexRay (standardized by the ISO 17458 standard) or Ethernet (standardized by the ISO / IEC 802-3 standard).

[0125] According to a particular and non-limiting exemplary embodiment, the device 3 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 3.

[0126] Figure 4 illustrates a flowchart of the different steps of a method for controlling a vehicle regulation system, for example an ACC system 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 3 of Figure 3.

[0127] In a first step 41, a signaling element is detected at a first time instant.

[0128] In a second step 42, a first time interval associated with a first phase of a vehicle speed regulation profile and a second time interval associated with a second phase of the profile are determined, the second phase temporally following the first phase.

[0129] A target speed of the vehicle is further determined based on the detected signal element, the target speed being associated with a third phase of the profile, the third phase temporally following the second phase, the third phase having a determined duration.

[0130] The start of the first time interval is determined based on a result of a comparison between a first target deceleration value associated with the first phase and a current deceleration value determined based on a current speed of the vehicle, the target speed, a current distance between the vehicle and the signaling element and the determined duration of the third phase. The start of the second time interval is determined based on a result of a comparison between a second target deceleration value associated with the second phase and the current deceleration value, the second target deceleration value being less than or equal to the first target deceleration value. In a third step 43, the cruise control system is controlled according to the cruise control profile determined in the second operation.

[0131] According to a variant, the variants and examples of the operations described in relation to Figure 1 and / or 2 apply to the steps of the method of Figure 4. Of course, the present invention is not limited to the exemplary embodiments described above and also relates to a method for determining a speed regulation profile for a vehicle, for example an autonomous vehicle. The same would apply to a device configured for the implementation of such a method.

[0132] The present invention also relates to a vehicle cruise control system comprising the device 3 of Figure 3.

[0133] The present invention also relates to a vehicle, for example an automobile or more generally an autonomous land-based motor vehicle, comprising the device 3 of FIG. 3 or the vehicle speed regulation system above.

Claims

DEMANDS 1. Method for controlling a speed regulation system of a vehicle (10), said vehicle (10) travelling on a portion of road (101) approaching a signal element (110), said method comprising the following steps: - detection (41) of said signaling element at a first time instant; - determination (42) of a first time interval associated with a first phase (21) of a speed regulation profile of said vehicle (10), of a second time interval associated with a second phase (22) of said profile, said second phase (22) temporally following said first phase (21), and determination (42) of a target speed of said vehicle (10) as a function of said detected signaling element (110), said target speed being associated with a third phase (23) of said profile, said third phase (23) temporally following said second phase (22), said third phase (23) having a determined duration, a start of said first time interval being determined as a function of the result of a comparison between a first target deceleration value associated with said first phase (21) and a current deceleration value determined as a function of a current speed of said vehicle (10), of said target speed,of a current distance between said vehicle (10) and said signaling element (110) and of said determined duration of the third phase (23), and a start of said second time interval being determined based on a result of a comparison between a second target deceleration value associated with said second phase (22) and said current deceleration value, said second target deceleration value being less than or equal to said first target deceleration value; - control (43) of said speed regulation system according to said speed regulation profile.

2. A method according to claim 1, wherein the beginning of said first time interval is equal to a second time instant corresponding to, when said vehicle (10) is at a distance less than a determined distance from said signaling element (110), the time instant at which said current deceleration value reaches said first target deceleration value, and the beginning of said second time interval is equal to a third time instant corresponding to the time instant at which said current deceleration value reaches said second target deceleration value.

3. A method according to claim 1 or 2, wherein said current deceleration value, denoted d n , is determined according to the following equation: dn = (TargetV 2 - V 2 ) / (2 * (D - X * Target speed)) with Target speed corresponding to said target speed, V corresponding to the current speed of said vehicle (10), D corresponding to the current distance between said vehicle (10) and said signaling element (110) and X corresponding to said determined duration of the third phase (23).

4. A method according to any one of claims 1 to 3, wherein said signaling element belongs to a set of signaling elements comprising: - a STOP sign; - a YIELD sign; - a red traffic light; and - a green traffic light.

5. Method according to claim 4, wherein said target speed is 25 km / h when said signal element corresponds to the YIELD sign, said target speed is 30 km / h when said signal element corresponds to the STOP sign or the traffic light in red and said target speed is 50 km / h when said signal element corresponds to the traffic light in green.

6. A method according to any one of claims 1 to 5, wherein the determined duration of said third phase is 5 seconds, and said first target deceleration value is -0.3 ms. 2 and said second target deceleration value is -0.7 ms' 2 or -1.2 ms' 2 .

7. A method according to any one of claims 1 to 6, wherein said profile further comprises a fourth phase between said second phase (22) and said third phase (23) when a speed of said vehicle (10) reaches a value lower than said target speed before the start of said third phase, an acceleration value being associated with said fourth phase, said acceleration value being determined so that a speed of said vehicle (10) at the end of the fourth phase is equal to said target speed.

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

9. Device (3) for controlling a vehicle's speed regulation system, said device (3) comprising a memory (31) associated with at least one processor (30) configured for carrying out the steps of the method according to any one of claims 1 to 7.

10. Vehicle (10) comprising the device (3) according to claim 9.