EP4251487A1

EP4251487A1 - Method and device for adapting a setpoint acceleration trajectory of an adaptive vehicle cruise control of an autonomous vehicle

Info

Publication number: EP4251487A1
Application number: EP21816125.5A
Authority: EP
Inventors: Luc VIVET
Original assignee: PSA Automobiles SA
Current assignee: Stellantis Auto SAS
Priority date: 2020-11-30
Filing date: 2021-10-27
Publication date: 2023-10-04
Also published as: FR3116782B1; FR3116782A1; WO2022112677A1

Abstract

The invention relates to a method and a device for adapting a setpoint acceleration trajectory of an adaptive vehicle cruise control of an autonomous vehicle, in order for the autonomous vehicle to reach a target position at a target speed while respecting dynamic acceleration constraints, the method comprising the steps of: • receiving (301) information on the setpoint acceleration trajectory, on the target position, on the target speed and on the dynamic acceleration constraints; • estimating (302) an end position and an end speed of the autonomous vehicle, taking into account the dynamic acceleration constraints; • if (303) the difference between the end position and the target position is greater than a predetermined position threshold, or if (303) the difference between the end speed and the target speed is greater than a predetermined speed threshold, an adaptation (304) of the setpoint acceleration trajectory is determined.

Description

DESCRIPTION

Title: Method and device for adapting a setpoint acceleration trajectory of an adaptive vehicle cruise control of an autonomous vehicle.

The present invention claims the priority of French application 2012390 filed on 30.11.2020, the content of which (text, drawings and claims) is incorporated herein by reference.

The invention is in the field of autonomous vehicle driving assistance systems. In particular, the invention relates to a method and a device for adapting a setpoint acceleration trajectory of an adaptive vehicle cruise control of an autonomous vehicle, so that said autonomous vehicle reaches a target position at a speed target while respecting dynamic acceleration constraints, said autonomous vehicle comprising a computer.

“Vehicle” means any type of vehicle such as a motor vehicle, moped, motorcycle, warehouse storage robot, etc. “Autonomous driving” of an “autonomous vehicle” means any process capable of assisting the driving of the vehicle. The method can thus consist in partially or totally directing the vehicle or providing any type of assistance to a natural person driving the vehicle. The process thus covers all autonomous driving, from level 0 to level 5 in the OICA scale, for Organization International des Constructeurs Automobiles.

The processes capable of assisting the driving of the vehicle are also called ADAS (from the English acronym “Advanced Driver Assistance Systems”), ADAS systems or driver assistance systems. A vehicle speed regulator, RW, is a known ADAS system which regulates the speed of the vehicle according to a given speed setpoint, called setpoint speed. During a change in the set speed, several trajectories of the vehicle speed (temporal evolution of the vehicle speed) to reach the set speed are then possible. Following a vehicle speed trajectory determines an acceleration of the vehicle, and therefore a dynamic behavior of the vehicle. Some regulators are also determined taking into account the acceleration and, therefore, generate a trajectory setpoint acceleration, i.e. they determine the desired acceleration at each instant to reach a target speed.

An adaptive vehicle cruise control, or ACC (from the English acronym "Adaptive Cruise Control"), is an evolution of an RW. An ACC is also a known ADAS system which regulates the speed of the vehicle and an inter-vehicular time, the inter-vehicular time representing a time separating the passage of the front or the rear of two successive vehicles on the same lane of traffic. For example, the inter-vehicular time is a parameter predetermined by the driver or by default according to a recommendation of the regulations in force (2 seconds for example). The predetermined inter-vehicular time is also referred to below as the target time.

A device of a vehicle comprising the ACC function is able to acquire longitudinal dynamic characteristics of the vehicle and of a preceding vehicle, called preceding vehicle. This device comprises for example a camera, a radar, a lidar, etc. This device is capable of detecting the arrival of the preceding vehicle. This is the case, for example, when a vehicle falls back on the same traffic lane as the autonomous vehicle, or when the autonomous vehicle catches up with a vehicle which precedes it on the same traffic lane and which is traveling more slowly. In particular, a speed and acceleration of the autonomous vehicle, a speed and acceleration of the preceding vehicle, and a distance between the autonomous vehicle and the preceding vehicle, called inter-vehicular or inter-vehicle distance, are measured. By using vehicle speed information, the inter-vehicle time is deduced from the inter-vehicle distance, and the converse is also true. When a preceding vehicle is detected, the speed of the autonomous vehicle must be adapted in order to respect the target time. Conventionally, the speed of the preceding vehicle, which is measured, is taken as the target speed. The cruise control adapts the speed, and therefore the acceleration, of the autonomous vehicle to dock with the vehicle in front. The term "docking" means adapting, over a determined period, the speed of the autonomous vehicle to reach that of the preceding vehicle while respecting the inter-vehicular time at the end of the determined duration. The vehicle speed regulator then determines a setpoint acceleration trajectory that the autonomous vehicle must follow. This determines a docking behavior (behavior of the longitudinal dynamics of the autonomous vehicle) always identical. It also determines a target speed and a target position.

However, the setpoint acceleration trajectory determined cannot take into account dynamic acceleration constraints because this is too complex. “Dynamic acceleration constraints” means acceleration thresholds that the autonomous vehicle must not exceed mainly for reasons of comfort, these thresholds being dependent on the states of the vehicle. For example, a state of the vehicle is the instantaneous speed of the vehicle (at an instant t), the position/geolocation of the vehicle (taking into account traffic signs, the curvature, the slope or the cant of the road, etc.) , the ability to brake or accelerate. For example, a dynamic acceleration constraint is not to have an acceleration less than -3.5 m/s ² if the speed is greater than 70 km/h, not to have an acceleration less than -5 m/s ² if the speed is less than 30 km/h, and, if the speed is between 30 km/h and 70 km/h, not have an acceleration below a threshold which varies linearly as a function of the speed and of the two thresholds preceding.

Currently, if a setpoint acceleration trajectory does not respect the dynamic constraints, the regulator saturates the setpoint acceleration: For example, the regulator takes the maximum between a negative setpoint acceleration and a negative acceleration constraint. Then, the regulator will not decelerate the vehicle sufficiently, and the target position and the target speed are not reached. This leads to additional setpoint acceleration trajectory generations using additional computing resources. Moreover, the docking behavior is no longer controlled.

In addition to the dynamic acceleration constraints, other dynamic constraints are likely to have to be taken into account such as dynamic constraints on the speed, on the jerk, on the jerk according to an instantaneous speed of the vehicle, etc.

An object of the present invention is to remedy the aforementioned problem, in particular the invention adapts the setpoint acceleration trajectory, without the need for numerous calculation resources. The docking behavior is then substantially equivalent to that desired: reaching a target speed at a target position. To this end, a first aspect of the invention relates to a method for adapting a setpoint acceleration trajectory of an adaptive vehicle cruise control of an autonomous vehicle, so that said autonomous vehicle reaches a target position at a target speed while respecting dynamic acceleration constraints, said autonomous vehicle comprising a computer, said method comprising the steps of:

• Reception by the computer of information on the target acceleration trajectory, on the target position, on the target speed and on the dynamic acceleration constraints;

• Estimation of a final position and a final speed of the autonomous vehicle from the target acceleration trajectory taking into account the dynamic acceleration constraints;

• If the difference between the final position and the target position is greater than a predetermined position threshold, or if the difference between the final speed and the target speed is greater than a predetermined threshold speed threshold, then an adaptation of the setpoint acceleration trajectory is determined from an amplitude dilation and a time dilation of the setpoint acceleration trajectory, while taking into account the dynamic acceleration constraints.

Thus, the setpoint acceleration trajectory is reused and adapted before y=effective use by the adaptive cruise control of the autonomous vehicle. The dynamic constraints are taken into account and the autonomous vehicle reaches the target speed with a close target position. Adapting the setpoint acceleration trajectory is not complex: a module generating the setpoint acceleration trajectories is not modified, an ACC regulation module which saturates the acceleration setpoints is not is not modified. The invention is a module which fits between known modules.

The setpoint acceleration trajectory is amplitude modulated and time modulated. For example, the adaptation will make the adapted setpoint acceleration trajectory decelerate stronger and faster in order to compensate for future saturations.

In one operating mode, the invention retrieves information on a setpoint acceleration trajectory such as, for example, parameter values of an analytical equation modeling the setpoint acceleration trajectory as a function of the time. From this equation, the final position and the final speed are calculated while taking into account the dynamic constraints. If performance tests, position and speed deviation are below predetermined thresholds, are not verified then this equation is modified in amplitude and time to find a suitable acceleration trajectory verifying performance criteria while respecting constraints dynamic. If the performance tests are verified, there is no need to adapt the trajectory.

Advantageously, the method further comprises a prior step of determining a new setpoint acceleration trajectory by the adaptive speed regulator, said adaptive speed regulator having received a new setpoint speed, said new setpoint acceleration trajectory defining a new target speed and a new target position.

Thus, the process is restarted if necessary, and a new adapted setpoint acceleration trajectory is determined according to new information.

Advantageously, a setpoint acceleration trajectory taking into account the dynamic acceleration constraints is represented by a function ax(a(t); c(t)), a(t) being a function representing the acceleration trajectory of setpoint, c(t) being a negative function representing the dynamic acceleration constraints, and f being a variable representing time.

Thus, the reception of information on the setpoint acceleration trajectory determines a function a(t) dependent on time f. The reception of information on the dynamic constraints of acceleration constitutes rules that can be evaluated at any time. This also determines a time-dependent function c(t) f. In the case of deceleration constraints, the function c(t) is negative. Taking the maximum at each instant f between the two functions a(t) and c(t) simply determines a setpoint acceleration trajectory taking into account the dynamic acceleration constraints, and thus a final position and a final speed are determined .

Advantageously, the amplitude dilation of the target acceleration trajectory is a function ka * a(t), and in which the time dilation of the target acceleration trajectory is a function a(kt * t), ka being a determined amplification constant, kt being a determined temporal modulation constant, a(t) being a function representing the setpoint acceleration trajectory with t a variable representing time.

Thus, only two constants are needed to adapt the setpoint acceleration trajectory. The amplification constant ka amplifies the trajectory. By "boost" is meant modifying the value of the setpoint acceleration trajectory, the modification can increase or decrease the value. Typically, ka is a constant close to 1. The temporal modulation constant kt hastens or slows down the appearance of the values of the setpoint trajectory. Typically, kt is a constant close to 1.

Advantageously, the adaptation of the setpoint acceleration trajectory determined from the amplitude dilation and the time dilation of the setpoint acceleration trajectory, while taking into account the dynamic acceleration constraints is a function a'(t) = max(ka * a(kt * t); c(kt * t)) , a(kt*t) being the function representing the time-modulated setpoint acceleration trajectory, c(kt*t ) being the negative function representing the dynamic constraints of temporally modulated acceleration, and f being the variable representing time, and kt being the temporal modulation constant.

Thus, for each instant, the adapted setpoint acceleration trajectory taking into account the dynamic constraints can be calculated according to a value of the constants ka and kt. A new final position and a new final speed are determined.

Advantageously, the amplification constant, ka, and the temporal modulation constant, kt, are determined such that the evaluation of the expression s = j(J a - l) ² + (kt - l) ² is the most possible, an adapted final position and an adapted final speed being calculated from the adapted target acceleration trajectory, the absolute value of the difference between the adapted final position and the target position being less than or equal to the predetermined position threshold and the absolute value of the difference between the adapted final speed and the target speed being less than or equal to the predetermined threshold speed threshold. Thus, the invention seeks to modify the setpoint acceleration trajectory as little as possible. The docking behavior of the vehicle obtained with an adapted setpoint acceleration trajectory is then very close to the desired docking behavior without the dynamic acceleration constraints.

Advantageously, the method further comprises a step of determining and emitting an alert signal when the evaluation of the expression is greater than a predetermined alert threshold.

Thus, the method identifies a situation where the adapted target acceleration trajectory becomes too far from the target acceleration trajectory. This situation indicates a dangerous situation requiring heavy braking, a change of lane or a change of strategy in the vehicle speed regulation. An alert signal is determined and then transmitted, for example, to the driver so that he can take over the steering of the vehicle or to another ADAS system to initiate emergency or harder braking, or a lane change, or a change of vehicle speed regulation strategy.

A second aspect of the invention relates to a device comprising a memory associated with at least one processor configured to implement the method according to the first aspect of the invention.

The invention also relates to a vehicle comprising the device.

The invention also relates to a computer program comprising instructions adapted for the execution of the steps of the method, according to the first aspect of the invention, when said program is executed by at least one processor.

Other characteristics and advantages of the invention will emerge from the description of the non-limiting embodiments of the invention below, with reference to the appended figures, in which:

[Fig. 1] schematically illustrates a device, according to a particular embodiment of the present invention.

[Fig. 2] schematically illustrates an adapted setpoint acceleration trajectory, according to a particular embodiment of the present invention. [Fig. 3] schematically illustrates a method for adapting a setpoint acceleration trajectory, according to a particular embodiment of the present invention.

The invention is described below in its non-limiting application to the case of an autonomous motor vehicle traveling on a road or on a traffic lane. Other applications such as a robot in a storage warehouse or a motorcycle on a country road are also possible.

FIG. 1 represents an example of a device 101 included in the vehicle, in a network (“cloud”) or in a server. This device 101 can be used as a centralized device in charge of at least certain steps of the method described below with reference to FIG. 2. In one embodiment, it corresponds to an autonomous driving computer or to a computer .

In the present invention, the device 101 is included in the vehicle.

This device 101 can take the form of a box comprising printed circuits, of any type of computer or even of a mobile telephone (“smartphone”).

The device 101 comprises a random access memory 102 for storing instructions for the implementation by a processor 103 of at least one step of the method as described above. The device also comprises a mass memory 104 for storing data intended to be kept after the implementation of the method.

The device 101 may also include a digital signal processor (DSP) 105. This DSP 105 receives data to shape, demodulate and amplify, in a manner known per se, this data.

Device 101 also includes an input interface 106 for receiving data implemented by the method according to the invention and an output interface 107 for transmitting data implemented by the method according to the invention.

[Fig. 2] schematically illustrates an adapted setpoint acceleration trajectory, according to a particular embodiment of the present invention. The axis 201 is an abscissa axis representing a time. A time t=0 indicates a start of a setpoint acceleration trajectory represented by the dashed curve 203, and a start of an adapted setpoint acceleration trajectory represented by the bold curve 206.

Axis 202 is an ordinate axis representing acceleration. Two accelerations are represented: a first at -3.5 m/s ² , a second at -5 m/s ² . Dashed curve 204 is a representation of dynamic acceleration stresses. For example, a dynamic acceleration constraint is not to have an acceleration lower than -3.5 m/s ² if the speed is higher than 70 km/h, not to have an acceleration lower than -5 m/s ² if the speed is less than 30 km/h, and, if the speed is between 30 km/h and 70 km/h, not have an acceleration below a threshold which varies linearly according to the speed and the two preceding thresholds . Here, the speed of the vehicle is not represented, but clearly this decreases depending on the cruise control.

On axis 201, tf represents a final time after which, if the adaptive cruise control applies the setpoint acceleration trajectory without the dynamic acceleration constraints, the vehicle reaches a target speed and a target position. The thin continuous line curve 205 represents an adapted setpoint acceleration trajectory without taking into account the dynamic acceleration constraints. Curve 203 has undergone an amplitude dilation: in this example, curve 205 has higher values. Curve 203 has also undergone a time dilation: in this example, the values of the amplified curve 203 arrive earlier.

The curve in solid bold line 206 represents the setpoint acceleration trajectory taking into account the dynamic acceleration constraints 204, the dynamic acceleration constraints being determined at each instant t from the history of the curve 205 between time 0 and time t.

The instant tf' represents a final time at the end of which, if the adaptive cruise control applies the adapted setpoint acceleration trajectory which takes into account the dynamic acceleration constraints, the vehicle has reached a value close to the target speed and the target position. [Fig. 3] schematically illustrates a method for adapting a setpoint acceleration trajectory, according to a particular embodiment of the present invention.

Step 301, “Recep”, is a step of reception by the computer 101 of information on the setpoint acceleration trajectory, on the target position, on the target speed and on the dynamic acceleration constraints.

For example, when the adaptive cruise control keeps the autonomous vehicle at a constant speed and a vehicle, called the preceding vehicle, enters the lane in front of said autonomous vehicle, the cruise control speed must adapt. The adaptation concerns the speed of the autonomous vehicle and the distance, or the inter-vehicular time, both of which are linked by the speed of the autonomous vehicle. An autonomous vehicle, conventionally comprising an adaptive speed regulation device, also comprises numerous sensors and computers capable of:

- Determine a setpoint acceleration trajectory, said trajectory being used by the adaptive cruise control so that the autonomous vehicle reaches a target position (or target inter-vehicular time) at a target speed. In particular, the trajectory is determined so that the adaptive cruise control causes the autonomous vehicle to dock with the preceding vehicle;

- Contain dynamic acceleration constraints.

The computer 101 or a computer of the adaptive speed regulator then receives information from the information on the setpoint acceleration trajectory, on the target position, on the target speed and on the dynamic acceleration constraints. In one operating mode, information on the setpoint acceleration trajectory are parameters of a model modeling the movement of the autonomous vehicle as a function of time. For example, this model is a polynomial of order 5, and the parameters are identified from initial conditions (initial distance, initial speed, initial acceleration, ...) or/and target conditions (target distance/position, speed target, target acceleration, ...).

In one operating mode, the target speed is a speed of the preceding vehicle or an extrapolation of the speed of the preceding vehicle if several measurements could be taken. The target position is a distance corresponding to a target inter-vehicle time with respect to a position of the preceding vehicle estimated at a time target, the target instant being determined by a duration of the setpoint acceleration trajectory.

In an operating mode, the dynamic constraints are rules of the type: - 3.5 m/s ² if the speed is greater than 70 km/h, -5 m /s ² if the speed is less than 30 km/h, and, if the speed is between 30 km/h and 70 km/h, an acceleration which varies linearly as a function of the speed and of the -3.5 m/s ² and 5 m/s ² thresholds. For example, these rules are inserted into tables.

Step 302, “Estim”, is a step for estimating a final position and a final speed of the autonomous vehicle from the setpoint acceleration trajectory by taking into account the dynamic acceleration constraints.

In one operating mode, a setpoint acceleration trajectory taking into account the dynamic acceleration constraints is represented by a function ax(a(t); c(t)), a(t) being a function representing the trajectory d setpoint acceleration, c(t) being a negative function representing the dynamic acceleration constraints, and f being a variable representing time.

For example, the information on the setpoint acceleration trajectory are parameters of a model modeling the movement of the autonomous vehicle as a function of time, and the dynamic acceleration constraints are decelerations not to be exceeded as a function of the speed. of the vehicle. By successive integrations, knowing the initial conditions, the position, the speed and the acceleration are determined at each instant. By way of illustration, with a time step of 1 second, if at a given instant the speed of the vehicle is 20 m/s, if at this given instant the setpoint acceleration trajectory gives an acceleration of -2 m /s ² , if a dynamic acceleration constraint is -1 m/s for a speed greater than 10 m/s ² , then after one second the speed of the vehicle will be 19 m/s (instead of 18 m/s ² without the constraint). When constraints are not respected, the acceleration of the vehicle is not that desired. The same goes for vehicle speed and position.

Step 303, “Test”, is a test step which verifies whether the difference between the final position and the target position is greater than a predetermined position threshold, or whether the difference between the final speed and the target speed is greater than a predetermined threshold speed threshold. In one operating mode, the position threshold is around 0.5 meters, and the speed threshold is around 0.05 m/s. In the affirmative, therefore in the presence of excessively large deviations, the dynamic behavior of the vehicle is not that desired, and the docking behavior will not be that desired. The method goes to step 304. Otherwise, the method returns to step 301.

Step 304, "Adapt", is a step where an adaptation of the target acceleration trajectory is determined from an amplitude dilation and a time dilation of the target acceleration trajectory, while taking into account the dynamic acceleration constraints.

In one mode of operation the amplitude dilation of the setpoint acceleration path is a function ka * a(t), and in which the time dilation of the setpoint acceleration path is a function a(kt * t) , ka being a determined amplification constant, kt being a determined temporal modulation constant, a(t) being a function representing the setpoint acceleration trajectory with t a variable representing time. For example, if a(t) is a polynomial function of time, it is simple to evaluate the acceleration at each instant t, it is simple to multiply this evaluation by a constant ka which expands the amplitude: if a(t =1 s)=-3 m/s ² and ka=1.1, then ka ^* a(t=1 s)=-3.3 m/s ² . Since it is possible to evaluate the acceleration at each instant t, it is also possible to evaluate the acceleration at an instant kt*t, kt being a temporal modulation constant: if a(t=0.9 s )=-2.8 m/s ² , and if kt=0.9, then we can define an a'(t=1 s) such that a'(1)=a(kt ^* 1=0.9 ^* 1=0.9)=-2.8 m/s ² .

In one embodiment, the adaptation of the setpoint acceleration path determined from the amplitude dilation and the time dilation of the setpoint acceleration path, while taking into account the dynamic constraints of acceleration is a function a'(t) = max(ka * a(kt * t); c(/ct * t)) , a(kt*t) being the function representing the time-modulated setpoint acceleration trajectory, c(kt*t) being the negative function representing the dynamic constraints of temporally modulated acceleration, and sucking the variable representing time, and kt being the temporal modulation constant. If the setpoint acceleration trajectory is modeled by a function a(t), then a′(t) models the adaptation of the setpoint acceleration trajectory. In one procedure, the amplification constant, ka, and the temporal modulation constant, kt, are determined such that the evaluation of the expression s = jika - l) ² + ( kt - l) ² is the most possible, an adapted final position and an adapted final speed being calculated from the adapted target acceleration trajectory, the absolute value of the difference between the adapted final position and the target position being less than or equal to the predetermined position threshold and the absolute value of the difference between the adapted final speed and the target speed being less than or equal to the predetermined threshold speed threshold. In the same way as in step 302, having a model of the adaptation of the target acceleration trajectory by successive integration at each time step, an adapted final position and adapted final speed are calculated. Different classic methods exist to solve this optimization problem: test of a set of values for ka and kt, successive iterations, dichotomy, double loop...

Advantageously, the method according to the invention further comprises a step of determining and transmitting an alert signal when the evaluation of the expression is greater than a predetermined alert threshold. Indeed, constructing the adaptation of the setpoint acceleration trajectory makes it possible to know exactly what the limits of the system are. When the constraints are too strong, for example having an s greater than 0.2, the invention finds the least worst of the trajectories, and then determines and emits an alert signal. In one operating mode, a new setpoint acceleration trajectory is determined by the ACC but with an inter-vehicular time shorter than that desired.

The present invention is not limited to the embodiments described above by way of examples; it extends to other variants.

The consideration of dynamic acceleration constraints has been detailed. The invention is not limited to dynamic acceleration constraints alone, and extends to any type of other form of dynamic constraints such as dynamic constraints on the speed, dynamic constraints on the jerk, dynamic constraints on the jerk according to an instantaneous speed of the vehicle ... Equations and calculations have also been detailed. The invention is not limited to the form of these equations and calculations, and extends to any type of other mathematically equivalent form.

Claims

1. Method for adapting a setpoint acceleration trajectory of an adaptive vehicle cruise control of an autonomous vehicle, so that said autonomous vehicle reaches a target position at a target speed while respecting dynamic constraints of acceleration, said autonomous vehicle comprising a computer (101), said method comprising the steps of:

• Reception (301) by the computer (101) of information on the target acceleration trajectory, on the target position, on the target speed and on the dynamic acceleration constraints;

• Estimation (302) of a final position and a final speed of the autonomous vehicle from the setpoint acceleration trajectory taking into account the dynamic acceleration constraints;

• If (303) the difference between the final position and the target position is greater than a predetermined position threshold, or if (303) the difference between the final speed and the target speed is greater than a predetermined speed threshold, then an adaptation (304) of the setpoint acceleration path is determined from an amplitude dilation and a time dilation of the setpoint acceleration path, while taking into account the dynamic constraints of acceleration.

2. Method according to claim 1, in which the method further comprises a prior step of determining a new setpoint acceleration trajectory by the adaptive speed regulator, said adaptive speed regulator having received a new setpoint speed, said new target acceleration trajectory defining a new target speed and a new target position.

3. Method according to one of the preceding claims, in which a setpoint acceleration trajectory taking into account the dynamic acceleration constraints is represented by a function max(a(t); c(t)), a(t ) being a function representing the setpoint acceleration trajectory, c(t) being a function negative representing the dynamic acceleration constraints, and sucking a variable representing time.

4. Method according to one of the preceding claims, in which the amplitude dilation of the setpoint acceleration trajectory is a function ka*a(t), and in which the time dilation of the setpoint acceleration trajectory is a function a(kt*t), ka being a determined amplification constant, kt being a determined temporal modulation constant, a(t) being a function representing the setpoint acceleration trajectory with t a variable representing time.

5. Method according to claim 4, in which the adaptation (304) of the target acceleration trajectory determined from the amplitude dilation and the time dilation of the target acceleration trajectory, while taking into account the dynamic acceleration constraints is a function a'(t) = max(ka * a(kt * t); c(kt * t)) , a(kt*t) being the function representing the trajectory of temporally modulated setpoint acceleration, c(kt*t) being the negative function representing the dynamic constraints of temporally modulated acceleration, and t being the variable representing time, and kt being the temporal modulation constant.

6. Method according to one of Claims 4 or 5, in which the amplification constant, ka, and the temporal modulation constant, kt, are determined such that the evaluation of an expression s = (ka - l) ² + ( kt - l) ² is as small as possible, an adapted final position and an adapted final speed being calculated from the adapted target acceleration path, the absolute value of the difference between the adapted final position and the position target being less than or equal to the predetermined threshold position and the absolute value of the difference between the adapted final speed and the target speed being less than or equal to the predetermined threshold speed threshold.

7. Method according to claim 6, in which the method further comprises a step of determining and emitting an alert signal when the evaluation of the expression is greater than a predetermined alert threshold.

8. Device (101) comprising a memory (102) associated with at least one processor (103) configured to implement the method according to one of the preceding claims.

9. Vehicle comprising the device according to the preceding claim.

10. Computer program comprising instructions adapted for the execution of the steps of the method according to one of claims 1 to 7 when said program is executed by at least one processor (103).