Method for evaluating common dynamic limits of a motor vehicle.

Abstract

Method for evaluating the current dynamic limits of a motor vehicle at a given time. The method comprises: - a means for measuring dynamic values ​​actually applied by the motor vehicle, and - a system capable of defining desired dynamic limits of the motor vehicle. The method comprises: - a step (E1) of receiving desired dynamic limits from the system, then - a step (E2) of comparing the desired dynamic limits with the dynamic values ​​actually applied by the vehicle, then (i) if the dynamic values ​​actually applied correspond to the desired dynamic limits, a return to step (E1) of receiving the desired dynamic limits, (ii) otherwise,a step (E4) of implementing a degraded operating mode including a determination of current dynamic limits of the motor vehicle as a function of the set of dynamic values ​​actually applied by the motor vehicle. Figure for the abstract: 2,

Description

Title of the invention: Method for evaluating common dynamic limits of a motor vehicle.

[0001] The invention relates to a method for evaluating the common dynamic limits of a motor vehicle. The invention further relates to a system for evaluating the common dynamic limits of a motor vehicle. The invention also relates to a motor vehicle comprising a system for evaluating the common dynamic limits of a motor vehicle.

[0002] Certain motor vehicles include applications and a planning system capable of defining and applying movement maneuvers, in particular according to a desired dynamic, i.e. according to ranges of desired speed and / or acceleration and / or jerk values.

[0003] However, it is possible that a desired dynamic defined by an application or a planning system may not be applicable by the actuators of the motor vehicle, for example because of weather conditions.

[0004] The object of the invention is to provide a system for evaluating the common dynamic limits of a motor vehicle, overcoming the above drawbacks and improving upon prior art systems for evaluating the common dynamic limits of a motor vehicle. In particular, the invention makes it possible to implement a simple and reliable system and method for evaluating the common dynamic limits of the motor vehicle.

[0005] To this end, the invention relates to a method for evaluating the current dynamic limits of a motor vehicle at a given instant, the current dynamic limits comprising one or more intervals of speed and / or acceleration and / or jerk values ​​that the motor vehicle is capable of achieving at the given instant, the vehicle comprising - a means of measuring dynamic values ​​actually applied by the motor vehicle, and - a trajectory planning system and / or a motor vehicle application capable of defining desired dynamic limits of the motor vehicle,

[0006] Furthermore, the method includes - a step of determining the current dynamic limits of the motor vehicle as being equal to the initial dynamic limits of the motor vehicle, - a step of receiving the desired dynamic limits from the planning system or application, then - a comparison step, at the desired dynamic limits, of a set of dynamic values ​​actually applied by the motor vehicle, the set of dynamic values ​​being measured by the measuring means, then (i) if the set of dynamic values ​​actually applied by the motor vehicle corresponds substantially to the desired dynamic limits, a feedback loop to the stage of receiving the desired dynamic limits, (ii) otherwise, a step of assigning an initial value to the current dynamic limits of the motor vehicle, the initial value corresponding to a product of the predefined dynamic limits by a first factor strictly less than 1, then - a step of implementing a degraded operating mode comprising a determination of current dynamic limits of the motor vehicle as a function of the set of dynamic values ​​actually applied by the motor vehicle.

[0007] In one embodiment, the step of implementing a degraded operating mode comprises the following substeps: - a first sub-step of initializing an iteration counter to a zero value, then - an iteration on a second and a third sub-step, the iteration also optionally covering a fourth and / or a fifth and / or a sixth sub-step: (i) the second sub-step comprising an increment of the iteration counter, then the starting of a timer of a given duration, then the collection of a set of dynamic values ​​actually applied by the motor vehicle during the elapsed time of the timer, (ii) the third sub-step, which runs after the time delay has elapsed, and includes a comparison of the set of dynamic values ​​actually applied with the current dynamic limits, (iii) the fourth substep comprising a reduction of the current dynamic limits by an amplitude, then a loop back to the initialization substep, (iv) the fifth substep comprising a comparison of a current value of the iteration counter to a maximum number of iterations, (v) the sixth sub-step comprising an increase in the vehicle's current dynamic limits.

[0008] In one embodiment, during the execution of the third sub-step, - if all the dynamic values ​​actually applied by the motor vehicle are strictly less than the current dynamic limits, the process proceeds to the fourth sub-step, then loops back to the first sub-step, - otherwise, the set of dynamic values ​​actually applied by the motor vehicle corresponds approximately to the current dynamic limits and we proceeds to the fifth sub-step, then if the current value of the counter is strictly less than the maximum number, we loop back to the second sub-step of incrementing the counter.

[0009] In one embodiment, in the fifth substep, when the current value of the counter is equal to the maximum number of iterations, we proceed to the sixth substep, then we loop back to the first substep.

[0010] In one embodiment, the step of receiving desired dynamic limits from the planning system or application includes - a substep of checking compatibility between the desired dynamic limits and the current dynamic limits of the motor vehicle, then, - if an amplitude of the desired dynamic limits is greater than an amplitude of the current dynamic limits, a substep of rejecting the desired dynamic limits.

[0011] In one embodiment, the current dynamic limits of the motor vehicle include - minimum and maximum values ​​for longitudinal vehicle speeds, and / or - minimum and maximum values ​​for longitudinal acceleration of the vehicle, and / or - minimum and maximum values ​​for longitudinal jerk, and / or - minimum and maximum values ​​of vehicle lateral speeds, and / or - minimum and maximum values ​​of vehicle lateral accelerations, and / or - minimum and maximum values ​​of lateral jerk.

[0012] In one embodiment, the fourth substep comprises a multiplication of the current dynamic limits by a first factor strictly less than 1 and / or the sixth substep comprises a multiplication of the current dynamic limits by a second factor strictly greater than 1.

[0013] In one embodiment, - the values ​​of the first and / or second factors are constant or variable over time, or - the values ​​of the first and second factors are inversely proportional.

[0014] The invention further relates to a system for evaluating the current dynamic limits of a motor vehicle at a given time, the system comprising a means for measuring dynamic values ​​actually applied by the motor vehicle, the system further comprising a trajectory planning system and / or an application of the motor vehicle capable of determining desired dynamic limits of the motor vehicle, the system comprising hardware and / or software elements implementing the process according to the invention, in particular hardware and / or software elements designed to implement the process according to the invention.

[0015] The invention further relates to a motor vehicle comprising a system for evaluating common dynamic limits according to the invention.

[0016] The motor vehicle 100 can be a motor vehicle of any type, including a passenger vehicle, a utility vehicle, a truck or a public transport vehicle such as a bus or a shuttle.

[0017] The motor vehicle 100 is a vehicle including driver assistance functions.

[0018] An embodiment of a motor vehicle 100 according to the invention is described below with reference to [Fig.1].

[0019] The motor vehicle 100 further includes a system 10 for evaluating common dynamic limits according to the invention.

[0020] System 10 comprises: - a means of measuring 11 dynamic values ​​actually applied by the motor vehicle at a given instant, i.e. speeds and / or accelerations and / or jerks actually applied by the motor vehicle at a given instant, the speeds and / or accelerations and / or jerks applied being able to be positive or negative, - a trajectory planning system 12 and / or an application 13 of the motor vehicle capable of determining desired dynamic limits of the motor vehicle.

[0021] The application 13 can be, for example, an advanced driver assistance system.

[0022] The measuring means 11 can be implemented by actuators of the motor vehicle.

[0023] Initial dynamic limits of the motor vehicle 100 are predefined, particularly during the design phase of the motor vehicle 100, and are then tested and calculated prior to series production of the vehicle. The initial dynamic limits are fixed, unlike the current dynamic limits of the vehicle, which vary over time. For example, the initial longitudinal dynamic limits of the motor vehicle 100 can be described by - a range of longitudinal accelerations between -10 m / s2 and +10 m / s2, - a range of lateral accelerations between -4 m / s2 and +4 m / s2, and - a range of longitudinal and lateral jerks between -3m / s3 and +3m / s3.

[0024] For another vehicle model, the initial longitudinal dynamic limits could be described by a range of longitudinal accelerations between -5 m / s2 and +5 m / s2.

[0025] The invention relates to the evaluation of current dynamic limits of the motor vehicle 100. The current dynamic limits of the vehicle depend on the characteristics of the vehicle but also on the context in which the vehicle is located at the current time, for example weather conditions, road conditions, etc.

[0026] In the remainder of this document, the terms "current dynamics" or "current dynamic limits" refer to one or more ranges of speed and / or acceleration and / or jerk values ​​that the vehicle is capable of achieving at any given time. For example, a lower limit of an acceleration range is a negative value representing the greatest possible deceleration that the vehicle can achieve. Similarly, an upper limit of an acceleration range is a positive value representing the greatest possible acceleration that the vehicle can achieve.

[0027] According to the embodiment, the current dynamic limits include - longitudinal and / or lateral velocity intervals, and / or - longitudinal and / or lateral acceleration intervals, and / or - longitudinal and / or lateral jerk intervals.

[0028] The evaluation system 10 has the role of providing in real time the current dynamic limits of the vehicle, so that they can be used by subsystems of the vehicle to determine maneuvers of the motor vehicle 100 or plan movements of the motor vehicle 100.

[0029] In addition to the measuring means 11, the trajectory planning system 12, and the application 13, the system 10 further comprises a microprocessor 14 which enables the execution of the method according to the invention, a local electronic memory 15 and communication interfaces 16 enabling the microprocessor 14 to read data in the memory 15 and to write data in the memory 15.

[0030] In one embodiment, the microprocessor 14 allows the execution of software comprising the following modules, which collaborate with each other: - a first module 141 for determining a first value of the current dynamics of the motor vehicle 100, the first module 141 collaborating with the memory 15, - a second module 142 for receiving desired dynamic limits, the second module 142 collaborating with the planning system 12 or the application 13, - a third module 143 for comparing, with the desired dynamic limits, dynamic values ​​actually applied by the motor vehicle, the third module 143 collaborating with the measuring means 11, - a fourth module 144 for determining the current dynamic limits of the motor vehicle as being equal to the desired dynamics, - a fifth module 145 for reducing the vehicle's current dynamic limits, - a sixth module 146 for increasing the current dynamic limits of the vehicle.

[0031] The system 1 for evaluating common dynamic limits includes means for implementing a method for evaluating common dynamic limits of the motor vehicle according to the invention, described below.

[0032] One embodiment of the method for evaluating common dynamic limits is illustrated by [Fig.2]. It comprises five steps, E0 to E4.

[0033] In step E0, current dynamic limits of the vehicle are determined to be equal to the initial dynamic limits described above. The initial dynamic limits are stored in memory 15, and they allow the process to be initialized without prior knowledge of data from speed sensors, acceleration sensors, or jerk sensors of the motor vehicle.

[0034] Then, in step El, desired dynamic limits are received from the planning system 12 or the application 13. In a substep Eli, it is verified that the desired dynamic limits are included in the initial dynamic limits.

[0035] If the desired dynamic limits are included in the initial dynamic limits, we proceed to step E2.

[0036] Otherwise we proceed to a sub-step E12, in which we reject the request from the planning system 13 or from an application 13 and we loop back to step E0.

[0037] In step E2, measurements are received from the measuring means 11, comprising a set of dynamic values ​​actually applied by the vehicle. The set of dynamic values ​​actually applied by the motor vehicle is then compared to the desired dynamic limits.

[0038] If the set of dynamic values ​​actually applied by the motor vehicle corresponds substantially to the desired dynamic limits, then we loop back to the El step of receiving desired dynamic limits from the planning system or an application.

[0039] Alternatively, if the set of dynamic values ​​actually applied by the motor vehicle does not correspond to the desired dynamic limits, then the current operating conditions of the motor vehicle do not allow the desired dynamic limits to be achieved. Step E3 then proceeds, in which an initial value is assigned to the current dynamic limits of the motor vehicle 100. This initial value corresponds to a product of the initial dynamic limits and a first factor strictly less than 1, for example, the first factor could be equal to 0.75.

[0040] Then we proceed to step E4 of implementation of a so-called "degraded" mode in which we determine current dynamic limits of the vehicle as a function of dynamic values ​​actually applied by the motor vehicle.

[0041] Step E4 includes a first substep E41 of initializing an iteration counter to a zero value, the iteration counter being stored in memory 15. Substep E41 is an input gate on two iteration loops B1 and B2.

[0042] Loop B1 implements successive reductions of the current dynamic limits. To do this, in the first loop Bl, iterates over substeps E41, E42, E43 and E44.

[0043] In substep E42, the iteration counter is incremented, and then a timer of a given duration is started, for example, between 10 and 20 seconds. During the entire timer period, a set of dynamic values ​​actually applied by the motor vehicle is collected. The collected data is stored in memory 15.

[0044] Then, when the time limit has expired, we proceed to substep E43, in which we compare the set of dynamic values ​​actually applied with the current dynamic limits of the motor vehicle.

[0045] If the set of dynamic values ​​actually applied by the motor vehicle, if the set of measured values ​​are strictly less than the current dynamic limits, we proceed to the fourth sub-step E44 of reducing an amplitude of the current dynamic limits.

[0046] The substep E44 of reducing an amplitude of the current dynamic limits includes a multiplication of the current dynamic limits by a first factor strictly less than 1.

[0047] Then we loop back to the initialization substep E41.

[0048] We thus traverse the loop Bl until an entry condition in the second loop B2 is verified, that is to say until we determine in substep E43 that the set of dynamic values ​​actually applied by the motor vehicle corresponds substantially to the current dynamic limits.

[0049] As a note, when exiting loop BL, the value of the iteration counter is always equal to 1, since the counter is reset at each iteration of loop BL

[0050] Conversely, - at the input of loop B2, that is to say in sub-step E42, the counter is incremented by one unit, - then at the exit of loop B2, that is to say in sub-step E45, we check if the counter has reached the maximum value N.

[0051] In one embodiment, the maximum value N is equal to 20.

[0052] As long as the counter is strictly less than the maximum value N, the loop B2 implements a series of timers to periodically check, in substep E43, that the set of dynamic values ​​actually applied by the motor vehicle corresponds substantially to the current dynamic limits.

[0053] As long as this condition is verified, after substep E43, we proceed to substep E45, in which we compare the value of the iteration counter to a maximum value N.

[0054] When this condition is no longer verified, in substep E43, we exit loop B2 and proceed to substep E44 to return to loop Bl, in order to adapt the current dynamic limits of the vehicle again to the dynamic values ​​actually applied by the motor vehicle.

[0055] When the counter of loop B2 reaches the maximum value N, it is known that the correspondence between the set of dynamic values ​​actually applied by the motor vehicle and the current dynamic limits is relatively durable.

[0056] We then proceed to substep E46 of increasing the current dynamic limits, comprising a multiplication of the current dynamic limits by a second factor strictly greater than 1. Then we loop back to step E41 of resetting the counter.

[0057] In one embodiment, - the values ​​of the first factor and / or second factor are constant or variable over time, or - the values ​​of the first and second factors are inversely proportional.

[0058] Thus, in substep E46, an increase in the current dynamic limits is applied, with the objective of adjusting the current dynamic limits as closely as possible to the dynamic values ​​implemented by the motor vehicle 100.

[0059] Then, we proceed to substep E41 to restart an execution cycle of step E4.

[0060] In other words, - Substep E46 has the effect of increasing the current dynamic limits until they cover the dynamic values ​​actually applied by the motor vehicle, - and substep E44 has the effect of reducing the current dynamic limits until they exclude values ​​of dynamic values ​​that the motor vehicle is not capable of applying.

[0061] Following sub-step E46, we proceed to sub-step E41, to restart an execution cycle of step E4.

[0062] We iterate in this way on step E4, until an exit condition from the degraded mode is verified.

[0063] A first condition for exiting step E4, i.e., degraded mode operation, relates to the fact that the current dynamic limits decrease until they reach a minimum dynamic limit threshold. In this case, the process proceeds to substep E12, which rejects the desired dynamic limits, and in which the request from the planning system or an application is rejected.

[0064] In one embodiment, the minimum threshold of the dynamic limits is reached when the current dynamic limits include a longitudinal acceleration value less than or equal to lm / s2, or even less than or equal to 0.5m / s2.

[0065] A second exit condition for step E4 relates to the fact that the current dynamic limits have remained at a level substantially equal to the initial dynamic limits for a duration of N time intervals. When the second exit condition is met, the process proceeds to step El, which receives a desired dynamic value from the planning system or the application.

[0066] Finally, the method according to the invention makes it possible to provide the current dynamic limits of the vehicle in real time.

[0067] Having real-time access to the vehicle's current dynamic limits allows automotive applications to operate more efficiently, i.e., according to the vehicle's actual capabilities. This is particularly true for a trajectory planner or for advanced driver assistance systems (ADAS).

[0068] The method according to the invention processes data from the vehicle's sensors or actuators. The method may also use various information, including information relating to weather conditions, tire grip on the road surface, etc.

[0069] The proposed algorithm is based on the processing of data available in the vehicle, particularly at the level of vehicle actuators or sensors. This feature makes it possible to adapt the vehicle's current dynamic limits in real time without having to observe, estimate, or model the entire driving scene.

[0070] Thus, the method according to the invention makes it possible to simply improve the processing of the vehicle's dynamic limits and to converge the current dynamic limits as quickly as possible with the dynamic values ​​actually applied by the motor vehicle

Claims

1. Demands A method for evaluating the current dynamic limits of a motor vehicle (100) at a given instant, the current dynamic limits comprising one or more ranges of speed and / or acceleration and / or jerk values ​​that the motor vehicle is capable of achieving at the given instant, the vehicle comprising - a means (11) for measuring dynamic values ​​actually applied by the motor vehicle, and - a trajectory planning system (12) and / or an application (13) for the motor vehicle capable of defining desired dynamic limits for the motor vehicle, the process being characterized in that it comprises - a step (E0) of determining current dynamic limits of the motor vehicle (100) as being equal to initial dynamic limits of the motor vehicle, - a step (E1) of receiving desired dynamic limits from the planning system (12) or the application (13), then - a step (E2) of comparing, to the desired dynamic limits, a set of dynamic values ​​actually applied by the motor vehicle (100), the set of dynamic values ​​being measured by the measuring means (11), then (i) if the set of dynamic values ​​actually applied by the motor vehicle (100) corresponds substantially to the desired dynamic limits, a feedback loop on the step (El) of receiving the desired dynamic limits, (ii) otherwise, a step (E3) of assigning an initial value to the current dynamic limits of the motor vehicle (100), the initial value corresponding to a product of the predefined dynamic limits by a first factor strictly less than 1, then - a step (E4) of implementing a degraded operating mode comprising a determination of current dynamic limits of the motor vehicle (100) as a function of the set of dynamic values ​​actually applied by the motor vehicle.

2. A method according to the preceding claim, characterized in that the step (E4) of implementing a degraded operating mode comprises the following substeps: - a first substep (E41) of initializing an iteration counter to a zero value, then - an iteration over a second and a third substep (E42, E43), the iteration optionally also including a fourth and / or a fifth and / or a sixth substep (E44, E45, E46): (i) the second substep (E42) comprising an increment of the iteration counter, then the starting of a timer of a given duration, then the collection of a set of dynamic values ​​actually applied by the motor vehicle (100) during the elapsed time of the timer, (ii) the third substep (E43) executing after the timer has elapsed,and including a comparison of the set of dynamic values ​​actually applied with the current dynamic limits, (iii) the fourth substep (E44) comprising a reduction of the current dynamic limits by an amplitude, then a loop back to the initialization substep (E41), (iv) the fifth substep (E45) comprising a comparison of a current value of the iteration counter to a maximum number (N) of iterations, (v) the sixth substep (E46) comprising an increase in the current dynamic limits of the vehicle.

3. A method according to the preceding claim, characterized in that, during the execution of the third substep (E43), - if the set of dynamic values ​​actually applied by the motor vehicle are strictly less than the current dynamic limits, we proceed to the fourth substep (E44), then we loop back to the first substep (E41), - otherwise, the set of dynamic values ​​actually applied by the motor vehicle corresponds substantially to the current dynamic limits and we proceed to the fifth substep (E45), then if the current value of the counter is strictly less than the maximum number (N), we loop back to the second substep (E42) of incrementing the counter.

4. Method according to the preceding claim, characterized in that, in the fifth substep (E45), when the current value of the counter is equal to the maximum number of iterations (N), we proceed to the sixth substep (E46), then we loop back to the first substep (E41).

5. A method according to any one of the preceding claims, characterized in that the step (El) of receiving desired dynamic limits from the planning system or application, comprises - a substep (El 1) of checking compatibility between the desired dynamic limits and the current dynamic limits of the motor vehicle, then, - if an amplitude of the desired dynamic limits is greater than an amplitude of the current dynamic limits, a substep (E12) of rejecting the desired dynamic limits.

6. A method according to any one of the preceding claims, characterized in that the current dynamic limits of the motor vehicle include - minimum and maximum values ​​of longitudinal vehicle speeds, and / or - minimum and maximum values ​​of longitudinal vehicle accelerations, and / or - minimum and maximum values ​​of longitudinal jerk, and / or - minimum and maximum values ​​of lateral vehicle speeds, and / or - minimum and maximum values ​​of lateral vehicle accelerations, and / or - minimum and maximum values ​​of lateral jerk.

7. A method according to any one of the preceding claims and according to claim 2, characterized in that the fourth substep (E44) comprises a multiplication of the current dynamic limits by a first factor strictly less than 1 and / or the sixth substep (E46) comprises a multiplication of the current dynamic limits by a second factor strictly greater than Q1

8. d 1. A method according to the preceding claim, characterized in that - the values ​​of the first and / or second factors are constant or variable over time, or - the values ​​of the first and second factors are inversely proportional.

9. System (10) for evaluating current dynamic limits of a motor vehicle at a given time, the system comprising a means (11) for measuring dynamic values ​​actually applied by the motor vehicle, the system further comprising a trajectory planning system (12) and / or an application (13) of the motor vehicle capable of determining desired dynamic limits of the motor vehicle (100), the system (10) being characterized in that it comprises hardware and / or software elements (11, 12, 13, 14, 15, 16, 141, 142, 143, 144, 145, 146) implementing the method according to any one of the preceding claims, in particular hardware (11, 12, 13, 14, 15, 16) and / or software elements designed to implement the method according to any one of the preceding claims.

10. Motor vehicle (100) comprising a system (10) for evaluating common dynamic limits according to the preceding claim.

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