Method and device for controlling an adaptive cruise control system on board a vehicle via steering wheel dynamics.

Abstract

The present invention relates to a method and a device for controlling an adaptive cruise control system on board a vehicle moving at a travel speed lower than a target speed. Indeed, the method comprises receiving (31) data representative of a steering wheel angle variation of the vehicle, the travel speed of the vehicle, a yaw rate of the vehicle, and a longitudinal acceleration of the vehicle. The method also comprises filtering (32) the steering wheel angle variation as a function of a first angular rotation threshold value, determining (33) a positive jerk gradient as a function of the received data and the filtered steering wheel angle variation and controlling (34) the ACC system as a function in particular of the positive jerk gradient, the received data and the filtered steering wheel angle variation. Figure for abstract: Figure 5

Description

Title of the invention: Method and device for controlling an adaptive cruise control system on board a vehicle via steering wheel dynamics. Technical field

[0001] The present invention relates to methods and devices for controlling an adaptive cruise control system on board a vehicle, in particular a motor vehicle. The present invention also relates to a method and a device for regulating the speed of a vehicle. Technological background

[0002] Some contemporary vehicles are equipped with functions or system(s) or driving assistance, known as AD AS (from the English “Advanced Driver-Assistance System” or in French “Advanced Driving Assistance System”).

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

[0004] Jerk is the derivative of acceleration with respect to time, this quantity representing, for example, jolts during sudden variations in acceleration.

[0005] The environmental information corresponds, for example, to the distance between the vehicle equipped with the ACC system and a vehicle traveling in front of it, to the speed (for example relative) of the vehicle traveling in front, to the acceleration (or deceleration) of the vehicle traveling in front and / or to a regulatory speed limit. Such a vehicle is called a target vehicle or target object of the ACC system. The acceleration setpoint(s) are, for example, determined from a control law based on estimates of the torque supplied by a powertrain (for example a thermal or electric engine) to one or more wheels of the vehicle and the current acceleration of the vehicle.

[0006] Such an ACC system acts on the behavior of the vehicle and thus influences the comfort of the occupants of a vehicle. It is therefore important to take this notion of comfort into account when developing such a driving assistance system. 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 comfort of the occupants of a vehicle having an adaptive cruise control system.

[0009] Another object of the invention is to improve the control of an adaptive cruise control system on board a vehicle.

[0010] According to a first aspect, the present invention relates to a method for controlling an adaptive cruise control system on board a vehicle, called an ACC system, the vehicle moving at a travel speed lower than a target speed, the method comprising the following steps: - reception of representative data: • a variation in the vehicle's steering wheel angle, • the vehicle's speed of movement, • a vehicle yaw rate, and • longitudinal acceleration of the vehicle; • a radius of curvature of a vehicle trajectory; - filtering the steering wheel angle variation as a function of a first angular rotation threshold value to obtain a filtered steering wheel angle variation, the angular rotation threshold value being determined from the movement speed; - determination of a gradient of a positive jerk as a function of: • filtered steering wheel angle variation, • a second angular rotation threshold value, and • a lateral acceleration of the vehicle determined from the travel speed and the yaw rate; - ACC system control in operation: • filtered steering wheel angle variation, • longitudinal acceleration, • lateral acceleration, • the positive jerk gradient, and • the radius of curvature of a vehicle trajectory.

[0011] Such a method makes it possible to obtain control of the adaptive cruise control system improving the comfort of the vehicle passengers by determining a jerk and its variation via the gradient, thus limiting longitudinal acceleration of the vehicle.

[0012] According to a variant of the method, the filtering is obtained by saturating the absolute value of the steering wheel angle variation with respect to the first threshold value of angular rotation and by sliding averaging of the saturated steering wheel angle variation when the absolute value of the saturated steering wheel angle variation decreases.

[0013] Such filtering makes it possible to reduce noise when recovering the value of steering wheel angle variation.

[0014] According to another variant, the lateral acceleration is determined by the following function: ^Lat ~ XV«,>»with: • aLat; the lateral acceleration of the vehicle (10), • V': the vehicle's yaw rate (10), . Vego • the vehicle's movement speed (10).

[0015] Calculating lateral acceleration makes it possible to determine its value more quickly than using a sensor.

[0016] According to yet another variant, the positive jerk gradient is determined by the following function: „ jr / ii \ i / 1 \ with: — 1^1 / • V JPos ; the positive jerk gradient, • aLat; the lateral acceleration of the vehicle; • kay(: a first coefficient depending on an absolute value of the lateral acceleration of the vehicle, • 5fa: the filtered steering wheel angle variation, • £5: the second angular rotation threshold value, and * / / R • a second coefficient depending on a ratio between the variation filtered steering wheel angle and the second angular rotation threshold value.

[0017] According to a variant of the additional method, the positive jerk is defined by the following function when a first condition is verified, the first condition being verified when a first prior lateral acceleration determined at a time instant prior to a current instant is greater than a first threshold acceleration: J Pas ( 0 — .t ( 1 a ref “ a CurvesRaw 1 ) aV£C ' * Jpo^J): Ie Jerk Posdif at an instant, • aref: the longitudinal acceleration of the vehicle, • ^CiïrvesRaw: the first threshold acceleration, and • / : a function using a lookup table.

[0018] The positive jerk is thus determined when a first condition corresponding to a vehicle located in a curve or a bend is verified.

[0019] According to another variant of the method, a corrected positive jerk is defined by the following function when a second condition is verified, said second condition being verified when the first condition is verified and a lateral acceleration an between the time instant and the current instant is less than a second threshold acceleration, the second threshold acceleration being less than the first threshold acceleration: Jpjt) = JpJj-At) VJPos if (JpaM -JpoAt-^ï) > JpoM = ^»(^0 + JpoM -JposÀ-^A S1 ( JPos{ t) - JPos( t-At ) ) < (At X VJp J with : • JPoAA: The positive jerk at an instant • jp (: the positive jerk corrected at an instant, . At: a time period, and • V JPox; the positive jerk gradient.

[0020] The corrected positive jerk is thus determined when a second condition corresponding to a vehicle located at the exit of a curve or a bend is verified.

[0021] According to yet another variant of the method, the control is a function, in addition, of a first maximum acceleration when the first condition is verified and the second condition is not verified and of a second maximum acceleration when the first and second conditions are verified, said first and second maximum accelerations being determined by the following functions: ^MaxCurvea ( 0 5 MaxCurveAjA ) ^MaxCurvesÀ^ ^MaxCurvesÀ + At (pMaxCm-veAA) ~ ^MaxCurvesA~^^ ) > ^MaxCurves(^ — ^MaxCurvesA'^ ') ^MaxCurvesA ') ~ ^MaxCurves^~^^ ( ^MaxCunes( ) ^MaxCurves( x Pos( 0) with : * aMaxC'urveA 0 • a First maximum acceleration at an instant f, * ^MaxCurves^ 0 • a second maximum acceleration at time1 • 8; a function using a lookup table, . VeSo • |the vehicle's movement speed (10), * vMaxCunxA^) • a maximum speed of movement as a function of the radius of curvature R, • At: a time period, * JpiAj): The Positive Jerk at an instant and • jp j: the positive jerk corrected at one moment!.

[0022] A maximum acceleration is thus defined in each of the situations and applicable when checking a vehicle's adaptive cruise control system.

[0023] According to a second aspect, the present invention relates to a device for controlling an adaptive speed regulation 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.

[0024] 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.

[0025] 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.

[0026] Such a computer program may use any programming language, and 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.

[0027] 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.

[0028] 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.

[0029] 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 an Internet-type network.

[0030] 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

[0031] 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 5, in which:

[0032] [Fig.l] schematically illustrates an environment of a vehicle, according to a particular and non-limiting exemplary embodiment of the present invention;

[0033] [Fig.2] schematically illustrates a passenger compartment of the vehicle of [Fig.l], according to a particular and non-limiting example of embodiment of the present invention;

[0034] [Fig.3] schematically illustrates a first curve of evolution of a variation steering wheel angle and a second curve of the filtered steering wheel angle variation, according to a particular and non-limiting exemplary embodiment of the present invention;

[0035] [Fig.4] schematically illustrates a device configured to control a system of adaptive speed regulation on board the vehicle of [Fig.l], according to a particular and non-limiting exemplary embodiment of the present invention;

[0036] [Fig.5] illustrates a flowchart of the different stages of a control process of a adaptive cruise control system on board the vehicle of [Fig.l], according to a particular and non-limiting exemplary embodiment of the present invention. Description of the exemplary embodiments

[0037] A method and a device for controlling an adaptive cruise control system on board a vehicle will now be described in the following with joint reference to FIGS. 1 to 5. The same elements are identified with the same reference signs throughout the description which follows.

[0038] The terms "first(s)", "second(s)" (or "first(s)", "second(s)"), etc. are used in this document by arbitrary convention to enable different elements (such as operations, means, etc.) implemented in the embodiments described below to be identified and distinguished. Such elements may be distinct or correspond to a single element, depending on the embodiment.

[0039] According to a particular and non-limiting example of embodiment, the present invention relates to a method and a device for controlling an adaptive cruise control system on board a vehicle moving at a travel speed lower than a target speed. Indeed, the method comprises receiving data representative of a variation in the steering wheel angle of the vehicle, the travel speed of the vehicle, a yaw rate of the vehicle, and a longitudinal acceleration of the vehicle. The method also comprises filtering the variation in the steering wheel angle as a function of a first threshold value of angular rotation, determining a gradient of a positive jerk as a function of the received data and the filtered variation in the steering wheel angle and controlling the ACC system as a function in particular of the positive jerk gradient, the received data and the filtered variation in the steering wheel angle.

[0040] [Fig.l] illustrates a vehicle 10, for example a motor vehicle, traveling on a portion of road 1001 of the environment 1. 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.

[0041] The vehicle 10 corresponds for example to a vehicle with a thermal engine, with electric motor(s) or even a hybrid vehicle with a thermal engine and one or more electric motors.

[0042] The vehicle 10 corresponds to a vehicle traveling under the total supervision of a driver or traveling in a semi-autonomous mode. The vehicle 10 travels according to a level of autonomy equal to 0 or according to a level of autonomy ranging from 1 to 2 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 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 AD AS system, and level 5 corresponding to a completely autonomous vehicle.

[0043] The 5 levels of autonomy of the classification of the federal agency responsible for road safety are: - level 0: no automation, the vehicle driver has full control over the main functions of the vehicle (engine, accelerator, steering, brakes); - level 1: driver assistance, automation is active for certain vehicle functions, the driver retaining overall control over the vehicle's driving; cruise control is part of this level, as are other aids such as ABS (anti-lock braking system) or ESP (programmed electro-stabilizer); - level 2: automation of combined functions, the control of at least two main functions is combined in the automation to replace the driver in certain situations; for example, adaptive cruise control combined with lane centering allows a vehicle to be classified as level 2, as does automatic parking assistance (from the English “Park assist”); - level 3: limited autonomous driving, the driver can cede complete control of the vehicle to the automated system which will then be in charge of critical safety functions; autonomous driving can however only take place in certain specific environmental and traffic conditions (only on motorways for example); - level 4: fully autonomous driving under certain conditions, the vehicle is designed to ensure all critical safety functions on its own over a complete journey; the driver provides a destination or navigation instructions but is not required to make himself available to take back control of the vehicle; - level 5: completely autonomous driving without driver assistance in all circumstances.

[0044] According to the example of [Fig.l], the vehicle 10 travels on a portion of road 1001 in a curve and makes a turn following a radius of curvature r.

[0045] The vehicle 10 includes in particular one or more driving assistance systems, called AD AS (from the English “Advanced Driver-Assistance System” or in French “Système d’aide à la conduite avance”), including an automatic speed regulation system, called ACC system. Such an AD AS system is configured to assist, or even replace, the driver of the vehicle 10 to control the vehicle 10 on its journey.

[0046] The first vehicle 10 for example carries one or more of the following sensors: - 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 the second vehicle 11 located in front of the vehicle 10 according to the example of [Fig.l]), with the aim of detecting obstacles and their distances from the vehicle 10; and / or - one or more LIDAR(s) (from the English “Light Detection And Ranging”, or “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 the second vehicle 11) located in the emitted light beam and to measure the distance between the sensor and each detected object; and / or - 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).

[0047] The data obtained from this or these sensors vary according to the type of sensor. When it is a radar or a LIDAR, the data correspond for example to distance data between points of the detected object and the sensor. Each detected object is thus represented by a point cloud (each point corresponding to a point of the object receiving the radiation emitted by the sensor and reflecting at least part of this radiation), the point cloud representing the envelope (or part of the envelope) of the detected object as seen by the sensor and ultimately by the vehicle 10 carrying the sensor. When it is a video camera, the data correspond to data associated with each pixel of the acquired image(s), for example gray level values ​​coded on for example 8, 10, 12 or more bits for each color channel, for example RGB (from the English “Red, Green, Blue” or in French “Rouge, vert, bleu”).This data makes it possible, for example, to determine positions. successive measurements taken by an object moving in the environment 1, for example the second vehicle 11, and to deduce therefrom one or more dynamic parameters of the moving object such as the position, the speed and / or the acceleration. These data also make it possible to determine the lines on the ground in order, for example, to participate in determining whether the second vehicle 11 and the vehicle 10 belong to the same traffic lane, for example.

[0048] The data acquired by the on-board sensor(s) feeds, for example, one or more systems on-board the vehicle 10, including the ACC system.

[0049] According to the example of [Fig.l], the vehicle 10 is moving at a current speed lower than a target speed determined for the ACC system. Such a situation arises for example when the vehicle 10 loses a target vehicle that it was following and which was moving at a speed lower than the target speed or when a user requests the vehicle 10 to move at a target speed higher than the current speed, for example by activating the ACC system or by increasing its target speed.

[0050] [Fig. 2] schematically illustrates a passenger compartment of a vehicle, for example the vehicle 10 of [Fig. 1], according to a particular and non-limiting exemplary embodiment of the present invention.

[0051] The vehicle 10 for example has a steering wheel 11 for steering the vehicle 10, for example by determining an angle of rotation of one or more wheels of the vehicle 10 via a mechanical and / or electrical connection. The invention is however not limited to a steering wheel 11, other devices such as a handlebar or a joystick are also suitable for guiding a vehicle.

[0052] The steering wheel 11 is for example connected to a steering wheel angle sensor 11.

[0053] A movement of the steering wheel 11 then generates a sending of data, for example to tination of a calculator, via one or more communication buses of the on-board system of the vehicle 10, for example a communication bus of the CAN (from the English "Controller Area Network" or in French "Réseau de contrôles") data bus type, 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), Ethernet (according to the ISO / IEC 802-3 standard) or LIN (from the English "Local Interconnect Network" or in French "Réseau interconnecté local").

[0054] Other on-board sensors or computers are also connected in communication, for example via the communication bus. This may be, for example, a vehicle speed sensor or an odometer, a longitudinal acceleration sensor or a wheel angle sensor.

[0055] A process for controlling an adaptive speed control system on board the vehicle 10, called the ACC system, is advantageously implemented by the vehicle 10, i.e. 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 of the vehicle 10.

[0056] In a first operation, data is received, for example by the computer responsible for controlling the ACC system. This data is representative of: • a variation in the steering wheel angle 11 of the vehicle 10, • the speed of movement of the vehicle 10, • a vehicle yaw speed of 10, • longitudinal acceleration of the vehicle 10, and • of a radius of curvature of a trajectory of the vehicle 10.

[0057] The longitudinal acceleration of the vehicle 10 is for example obtained from an acceleration sensor arranged along an axis x corresponding to the longitudinal axis of the vehicle 10 or from a multi-axis acceleration sensor, one of these axes being arranged along the direction x.

[0058] The yaw rate is for example obtained from a rotation speed sensor or determined from an angle sensor of a wheel of the vehicle 10.

[0059] The radius of curvature of a trajectory of the vehicle 10 is for example obtained from a computer determining this radius as a function of the angle of a wheel and the speed of the vehicle, from a measurement carried out by an optical system or from data from a map of an on-board navigation system.

[0060] In a second operation, the steering wheel angle variation is filtered according to a first angular rotation threshold value to obtain a filtered steering wheel angle variation. The angular rotation threshold value is in particular determined from the speed of movement of the vehicle 10, for example from a first correspondence table.

[0061] According to a particular embodiment example and illustrated by [Fig.3], the filtering is obtained by saturating the absolute value of the steering wheel angle variation with respect to the first threshold value of angular rotation and by sliding averaging over a determined time period of the saturated steering wheel angle variation when the absolute value of the saturated steering wheel angle variation decreases.

[0062] We observe on the curve corresponding to the variation in steering wheel angle 5 an exceeding of the first threshold value of angular rotation 2 x over the time periods t1, t2 and t3, the saturated steering wheel angle variation therefore follows a plateau over these periods.

[0063] A separation of the two curves is also observed when the absolute value of the steering wheel angle variation decreases after applying the sliding averaging of the saturated steering wheel angle variation.

[0064] Such filtering makes it possible to reduce noise or interference and is also effective when the vehicle 10 makes several turns consecutively.

[0065] In a third step, a gradient of a positive jerk is determined as a function of: • filtered steering wheel angle variation, • a second angular rotation threshold value, and • a lateral acceleration of the vehicle 10 determined from the movement speed of the vehicle 10 and the yaw speed of the vehicle 10.

[0066] According to a particular exemplary embodiment, the positive jerk gradient is determined by the following function:

[0067] [Math.l] VJPas “ (I a Lat 1 ) X | )

[0068] With: • VJPos ; the positive jerk gradient, • aLat; the lateral acceleration of the vehicle (10); • kav(: a first coefficient depending on an absolute value of the lateral acceleration of the vehicle (10), • 5fn: the filtered steering wheel angle variation, • ^3: the second angular rotation threshold value, and • . H 1 V second coefficient depending on a ratio between the variation « \ J y filtered steering wheel angle and the second angular rotation threshold value.

[0069] The first and second coefficients are for example determined empirically and are entered in correspondence tables or in a map.

[0070] According to a particular exemplary embodiment, the lateral acceleration is determined by the following function:

[0071] [Math.2] ^Lat ~ V' X Vego

[0072] With: • aLat; the lateral acceleration of the vehicle 10, • ÿ': the vehicle's yaw speed 10, . Vego • |vehicle movement speed 10.

[0073] Lateral acceleration is the acceleration along a transverse axis normal to the longitudinal axis x, this axis is represented by the transverse axis y in [Fig.l]. This transverse axis y is in particular oriented towards the instantaneous center of rotation of the vehicle 10.

[0074] The yaw rate of the vehicle 10 represents the angular speed of rotation of the vehicle 10 around a defined axis z normal to the longitudinal axes x and transverse axes y.

[0075] According to a particular embodiment, this yaw speed is determined by a computer of the vehicle 10 depending in particular on the angle of a wheel of the vehicle 10. Using the angle of a wheel rather than a sensor also makes it possible to determine this yaw rate more quickly and thus make the system more responsive. The gain in determining the yaw rate in relation to an angle of a wheel rather than by a sensor allows a gain of the order of 500ms to obtain this speed.

[0076] Lateral acceleration is a quantity which has a strong influence on the comfort of the occupants of the vehicle 10, in fact a strong variation in lateral acceleration in a bend creates discomfort for the occupants of the vehicle 10. It is therefore important to limit the variation in this lateral acceleration, in particular by limiting the jerk which, as a reminder, is the derivative of the lateral acceleration with respect to time. 1. In a fourth operation, the ACC system is controlled according to: • filtered steering wheel angle variation, • the longitudinal acceleration of the vehicle 10, • the lateral acceleration of the vehicle 10, and • of the gradient of said positive jerk, and Method for controlling an adaptive cruise control system on board a vehicle (10), called ACC system, said vehicle (10) moving at a travel speed lower than a target speed, said method comprising the following steps: - reception (31) of representative data: • a variation in the steering wheel angle (11) of the vehicle (10), • of said vehicle movement speed (10), • a vehicle yaw rate (10), • longitudinal acceleration of the vehicle (10), and • a radius of curvature of a trajectory of the vehicle (10); - filtering (32) said steering wheel angle variation as a function of a first angular rotation threshold value to obtain a filtered steering wheel angle variation, said angular rotation threshold value being determined from said movement speed; - determination (33) of a gradient of a positive jerk as a function of: • of said filtered steering wheel angle variation, • a second angular rotation threshold value, and • a lateral acceleration of the vehicle (10) determined from said movement speed and said yaw speed; - control (34) of said ACC system according to: • of said filtered steering wheel angle variation, • of said longitudinal acceleration, • of said lateral acceleration, • of said gradient of said positive jerk, and • the radius of curvature of a vehicle trajectory 10.

[0077] In a fifth operation, the type of situation is determined, a first type of situation corresponding to a vehicle 10 in a bend, a second type of situation corresponding to a vehicle 10 exiting a bend. In these two situations, it is appropriate to limit the variation in acceleration of the vehicle 10 to improve the comfort of the occupants of the vehicle 10.

[0078] The first situation, corresponding to a vehicle 10 in a bend, is characterized by the verification of a first condition. The first condition is verified when a first prior lateral acceleration determined at a time instant t ant prior to a current time instant is greater than a first threshold acceleration.

[0079] A positive jerk is then determined by the following function:

[0080] [Math.3] (0 — ( 1 ^ref ” ^CurvesRaw I )

[0081] With: • J: The positive jerk at an instant, • aref; the longitudinal acceleration of the vehicle (10), • acUrvesRaw ; the first threshold acceleration, and • f: a function using a lookup table.

[0082] The second situation, corresponding to a vehicle 10 exiting a bend, is characterized by the verification of a second condition. The second condition is verified when the first condition is verified and a previous lateral acceleration between the time instant tant and the current instant is less than a second threshold acceleration, the second threshold acceleration being less than the first threshold acceleration. This second situation thus occurs after the first situation, that is to say that the vehicle 10 exits a bend after having been in a bend.

[0083] A corrected positive jerk is then determined by the following function:

[0084] [Math.4] if [Math.4] , And

[0085] = + JpJj)-JpJl-4t) if

[0086] With:

[0087]

[0088]

[0089] • Jpo,f(j ): the positive jerk at an instant f, • ) / : the positive jerk corrected at one moment • At: a time period, and • V JPos; the positive jerk gradient. The positive jerk and the corrected positive jerk, for example, make it possible to determine a maximum acceleration in each of the previous situations. According to a particular embodiment, the control of the ACC system is furthermore a function of a first maximum acceleration when the first condition is verified and the second condition is not verified and of a second maximum acceleration when the first and second conditions are verified, said first and second maximum accelerations being determined by the following functions: [Math.5]

[0090] ^MaxCurves [Math.6] 'eg^MaxCurves ^MaxCurves(^t) aMaxCurves ) + ^1? X Jpas^) if [Math.6]

[0091] \uMaxC urves [Math.7] .. urves

[0092] ^MaxC urves \ 1 if [Math.7] ( ^MaxCurves ^McucCur ( ^ ) ^MaxCurvi with : (f-Æ) + ÜMaxCurves ^axCurves^'^)

[0093] • ^MaxCurves^): a First maximum acceleration at an instant, * atMaxCurves^): a second maximum acceleration at a timeT, • 8; a function using a lookup table, . Vego • |vehicle movement speed 10, * vMaxCurvek^): a maximum movement speed as a function of the radius of curvature R, • At: a time period, • JpOK{t ): The positive jerk at an instant f, and • j .( t ) • 'c Jerk Positive corrected at an instant. The V^faxCurves(R) function is a function using a lookup table, allowing the maximum speed of the vehicle in a curve to be determined. function of the radius of curvature of the vehicle trajectory 10.

[0094] The function S also uses a correspondence table, making it possible to determine a maximum acceleration of the vehicle 10 in a bend as a function of the difference between the maximum speed of the vehicle and its actual travel speed.

[0095] Thus, a longitudinal acceleration of the vehicle 10 determined by the ACC system is limited by the first maximum acceleration in a curve or bend, and is limited by the second maximum acceleration when exiting the curve or bend.

[0096] The comfort of the occupants of the vehicle 10 is thus improved, the variation in acceleration being thus restricted by, depending on the situations, the jerk, the corrected jerk and the jerk gradient.

[0097] Such a method thus makes it possible to improve the behavior law of the vehicle in an acceleration phase when cornering or exiting a corner.

[0098] [Fig. 4] schematically illustrates a device 2 configured to control an adaptive cruise control system on board a vehicle, for example the vehicle 10 of [Fig. 1], according to a particular and non-limiting exemplary embodiment of the present invention. The device 2 corresponds for example to a device on board the first vehicle 10, for example the ACC system computer.

[0099] The device 2 is for example configured for the implementation of the operations described with regard to figures 1 to 3 and / or the steps of the method 3 described with regard to [Fig.5]. 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 2, individually or in combination, can be integrated into a single integrated circuit, into several integrated circuits, and / or into discrete components. The device 2 can be produced in the form of electronic circuits or software (or computer) modules or even a combination of electronic circuits and software modules.

[0100] The device 2 comprises one (or more) processor(s) 20 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 2. The processor 20 may include integrated memory, an input / output interface, and various circuits known to those skilled in the art. The device 2 further comprises at least one memory 21 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.

[0101] The computer code of the embedded software(s) comprising the instructions to loaded and executed by the processor is for example stored in memory 21.

[0102] According to various particular and non-limiting embodiments, the device 2 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.

[0103] According to a particular and non-limiting exemplary embodiment, the device 2 comprises a block 22 of interface elements for communicating with external devices, for example a remote server, or the vehicle 10 when the device 2 corresponds to a smartphone or a tablet for example. The interface elements of the block 22 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”).

[0104] According to another particular and non-limiting exemplary embodiment, the device 2 comprises a communication interface 23 which makes it possible to establish communication with other devices (such as other computers of the on-board system or on-board sensors) via a communication channel 230. The communication interface 23 corresponds for example to a transmitter configured to transmit and receive information and / or data via the communication channel 230.The communication interface 23 corresponds for example to a wired network of the CAN (Controller Area Network), CAN FD (Controller Area Network Flexible Data-Rate), FlexRay (standardized by the ISO 17458 standard), Ethernet (standardized by the ISO / IEC 802-3 standard) or LIN (Local Interconnect Network).

[0105] According to a particular and non-limiting exemplary embodiment, the device 2 can provide output signals to one or more external devices, such as a screen. display, touch-sensitive or not, and / or other peripherals via respective output interfaces. According to one variant, one or other of the external devices is integrated into the device 2.

[0106] [Fig. 5] illustrates a flowchart of the different steps of a method 3 for controlling an adaptive speed regulation system on board a vehicle, for example the vehicle 10, according to a particular and non-limiting exemplary embodiment of the present invention. The method 3 is for example implemented by a device on board the vehicle 10 or by the device 2 of [Fig. 4].

[0107] In a first step 31, data is received. This data is representative of: • a variation in the steering wheel angle 11 of the vehicle 10, • the speed of movement of the vehicle 10, • a vehicle yaw rate of 10, and • longitudinal acceleration of the vehicle 10.

[0108] In a second step 32, the steering wheel angle variation is filtered as a function of a first angular rotation threshold value to obtain a filtered steering wheel angle variation, the angular rotation threshold value being determined from the movement speed of the vehicle 10.

[0109] In a third step 33, a gradient of a positive jerk is determined as a function of: • filtered steering wheel angle variation, • a second angular rotation threshold value, and • a lateral acceleration of the vehicle 10 determined from said movement speed of the vehicle 10 and the yaw speed of the vehicle 10.

[0110] In a fourth step 34, the adaptive speed control system is controlled according to: • filtered steering wheel angle variation, • the longitudinal acceleration of the vehicle 10, • the lateral acceleration of the vehicle 10, and • the positive jerk gradient.

[0111] According to a variant, the variants and examples of the operations described in relation to figures 1 to 3 apply to the steps of method 3 of [Fig.5].

[0112] The present invention also relates to an adaptive cruise control system for a vehicle comprising the device 2 of [Fig.4].

[0113] The present invention also relates to a vehicle, for example a motor vehicle or more generally a land motor vehicle, comprising the device 2 of [Fig.4] or the adaptive speed regulation system for vehicles above.

Claims

Claims

1. Method for controlling an adaptive cruise control system on board a vehicle (10), called an ACC system, said vehicle (10) moving at a travel speed lower than a target speed, said method comprising the following steps: - receiving (31) data representative of: • a steering wheel angle variation (11) of the vehicle (10), • said travel speed of the vehicle (10), • a yaw rate of the vehicle (10), • a longitudinal acceleration of the vehicle (10), and • a radius of curvature of a trajectory of the vehicle (10); - filtering (32) said steering wheel angle variation as a function of a first angular rotation threshold value to obtain a filtered steering wheel angle variation, said angular rotation threshold value being determined from said travel speed;- determination (33) of a gradient of a positive jerk as a function of: • said filtered steering wheel angle variation, • a second angular rotation threshold value, and • a lateral acceleration of the vehicle (10) determined from said travel speed and said yaw rate; - control (34) of said ACC system as a function of: • said filtered steering wheel angle variation, • said longitudinal acceleration, • said lateral acceleration, • said gradient of said positive jerk, and • said radius of curvature of a trajectory of the vehicle (10).;

2. A method according to claim 1, wherein said filtering is obtained by saturating the absolute value of said steering wheel angle variation with respect to said first threshold angular rotation value and by sliding averaging said saturated steering wheel angle variation when the absolute value of said saturated steering wheel angle variation decreases.

3. Method according to one of claims 1 to 2, for which said lateral acceleration is determined by the following function: ^Lat ~ V'x ^owith: • aLat; the lateral acceleration of the vehicle (10), • V'; the yaw rate of the vehicle (10), . Vego • |the speed of movement of the vehicle (10).

4. Method according to one of claims 1 to 3, for which the positive jerk gradient is determined by the following function: ™ i \ . z H ii 1 \ with: y J Pos - ^y ( ! aLat\ ) X \ | ^ | / •VJ Pos ; the positive jerk gradient, • aLat ; the lateral acceleration of the vehicle (10); • kay{ ): a first coefficient depending on an absolute value of the lateral acceleration of the vehicle (10), • 5fn : the filtered steering wheel angle variation, • : the second angular rotation threshold value, and • , / 1 $fu 1 \ : a second coefficient depending on a ratio between the filtered steering wheel angle variation and the second angular rotation threshold value.

5. Method according to one of claims 1 to 4, for which the positive jerk is defined by the following function when a first condition is verified, said first condition being verified when a first prior lateral acceleration determined at a time instant prior to a current instant is greater than a first threshold acceleration: JpoM = / ( )with: * JPoA^) • The Positive Jerk at an instant • ^ref ; the longitudinal acceleration of the vehicle (10), • acun 'esRaw ; the first threshold acceleration, and • / : a function using a lookup table.

6. The method of claim 5, wherein a corrected positive jerk is defined by the following function when a second condition is satisfied, said second condition being satisfied when the first condition is satisfied and a prior lateral acceleration between said time instant tant and said current instant is less than a second threshold acceleration, the second threshold acceleration being less than the first threshold acceleration: + 4txVJp„ / ' (JPos( 0 " JPos('^))> (dt x V JPos), and Jpo.M = Jpos(^t) +JPos(t) -Jpjj-At) If ( JPos ( r) " JPos ( X JPos) with : * J) • The Positive Jerk at an instant z, • j ( t ) • The corrected Positive Jerk at an instant f, • At ; a time period, and • V JPos ; the positive jerk gradient.

7. The method of claim 6, wherein said control is further a function of a first maximum acceleration when the first condition is satisfied and the second condition is not satisfied and a second maximum acceleration when the first and second conditions are satisfied, said first and second maximum accelerations being determined by the following functions: axCurves ( 0 — 8 ( go ~ MoxCurvest^) ) ^MaxCurves( 0 — ^MaxCurves^ ) "h Pas( 0 ^MaxCurves^) — ^MaxCurvesi f ^MaxCurves ( 0 " ^MaxCurvesi (.^MaxCurves^) ~ ^MaxCurvesU~^) ) ^Pos(j)) with: * aMaxCunei( 0 • a First maximum acceleration at an instant • à™ ( l ): a second maximum acceleration at an instant f, • 8 ; a function using a look-up table, • vego • the vehicle's moving speed (10), * vMa xCune^): a maximum moving speed as a function of the radius of curvature R, • At ; a time period, • JpOT(?): The positive jerk at an instant • j ( t ) • The corrected Positive Jerk at an instant f.

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 an adaptive vehicle speed regulation system, said device (3) comprising a memory (31) associated with at least one processor (30) configured for implementing the steps of the method according to any one of claims 1 to 7.

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

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