EP3065986A1

EP3065986A1 - Method and system for controlling the speed of a vehicle

Info

Publication number: EP3065986A1
Application number: EP14806007.2A
Authority: EP
Inventors: Fabrice Riesenmey; Olivier Beisbardt
Original assignee: Renault SAS
Current assignee: Renault SAS
Priority date: 2013-11-05
Filing date: 2014-11-05
Publication date: 2016-09-14
Also published as: CN105745132A; FR3012783A1; CN105745132B; FR3012783B1; WO2015067887A1

Abstract

The invention relates to a method and system for controlling the speed (V1) of a vehicle, in particular of an electric or hybrid vehicle capable of travelling on a roadway, said method including the following steps: estimating (15) the location of the vehicle on the roadway; predicting (16), in accordance with the location of the vehicle, a roadway zone (B) comprising a speed limit (V2) that said vehicle is likely to travel through; and determining a control current (I) of an energy-recovery device enabling the vehicle to reach said speed limit (V2) upon entering said zone (B) when the speed (V1) of the vehicle is higher than said speed limit (V2).

Description

METHOD AND SYSTEM FOR CONTROLLING THE SPEED OF A

VEHICLE

The present invention relates to a method of controlling the speed of a vehicle and a system for carrying out this method.

The invention also relates to a vehicle, in particular an electric or hybrid vehicle, comprising such a speed control system.

Traditionally, a traffic lane has zones each having a speed limitation different from that which precedes it. The speed limit must be respected by vehicles crossing the area concerned by this limitation.

Thus, when the vehicle arrives near such a zone the driver is generally warned by a sign that informs him of this speed limit to be respected.

This driver then acts on the vehicle to adapt the speed of the latter to this limit speed. To do this, for example when it is appropriate to slow down the pace of the vehicle to reach this speed limit, often the driver raises the foot of the accelerator a few meters before the road sign, then brakes when the vehicle enters the speed limit zone. By acting in this way, the speed of the vehicle is often not adapted to the speed limit in force in this area for a long time. To overcome this drawback, known in the state of the art, for example the patent application AU201 1 1 00733, speed control systems comprising a vehicle location module type GPS (acronym for "Global Positioning"). System ") able to evaluate the location of the vehicle and to determine the speed limit in force at this location.

This speed control system thus makes it possible on the basis of this information to maintain the speed of the vehicle at the speed limit in effect by acting on the engine and / or the braking system of the latter.

However, a major disadvantage of this system is that although it allows to maintain the speed of the vehicle at a limit speed when the vehicle is already traveling on this area, it can not avoid the sudden and not optimal deceleration of the vehicle in order to adapting its speed to the speed limit in effect when crossing the entrance to this zone because this slowdown remains achieved by the driver of the vehicle.

The present invention aims to remedy all or part of the various disadvantages mentioned above.

In this purpose, the invention relates to a method for controlling the speed of a vehicle, in particular an electric or hybrid vehicle, capable of running on a traffic lane, comprising the following steps:

- estimate of the location of the vehicle on the taxiway; prediction according to the location of the vehicle of a zone of the taxiway comprising a limit speed which is likely to be traversed by said vehicle, and

determining a control current of an energy recovery device enabling the vehicle to reach said limit speed at the entry of said zone when the speed of the vehicle is greater than said limit speed.

In other embodiments:

the step of determining the control current provides:

• determination of a negative acceleration constant of the vehicle;

An evaluation of the instant of launch of a deceleration of the vehicle over a distance to be traveled before reaching the zone, and

• a calculation of the control current as a function of the negative acceleration constant;

a step of activating a generator mode of an electric machine included in the energy recovery device, said electric machine being able to carry out a regenerative braking of energy during the deceleration of the vehicle so that said vehicle reaches the speed limit at the entrance of the zone;

the method comprises a step of determining a control current enabling the vehicle to reach a limit speed at the entry of a next zone when the speed of the vehicle is below this limit speed, said determining step of a control current providing:

• determination of a positive acceleration constant of the vehicle; An evaluation of an instant corresponding to the exit of the speed limit zone where the vehicle is traveling in order to launch a deceleration of the vehicle over a distance to be traveled before reaching the next zone, and

Calculating the control current as a function of said positive acceleration constant;

the method comprises a step of regulating the acceleration or deceleration of the vehicle;

the step of estimating the location of the vehicle provides a determination of the geographical coordinates of the position of the vehicle on the taxiway, and

the forecasting step provides a correlation of geographical coordinates relating to the position of the vehicle with mapping data for determining the area of the traffic lane comprising a speed limit.

The invention also relates to a system for controlling the speed of a vehicle, in particular an electric or hybrid vehicle, capable of running on a taxiway and comprising an energy recovery device, the system comprising a navigation device. and a device for controlling the energy recovery device, the navigation device is able to locate said vehicle on the taxiway and to identify an area of this taxiway that is likely to be traversed by said vehicle, said navigation device being able to interact with the control device so as to determine a control current of the energy recovery device enabling the vehicle to reach a limit speed at the entrance of said zone when the vehicle speed is greater than at the speed limit. In other embodiments:

the energy recovery device comprises an electric machine;

the navigation device comprises a locating module and is able to cooperate with modules for determining the speed and the acceleration / deceleration of the vehicle, and

- The navigation device comprises a storage module archiving mapping data including in particular speed limits of the taxiway areas.

The invention also relates to a vehicle, in particular an electric or hybrid vehicle, comprising such a speed control system. In another aspect, the invention also relates to a computer program comprising program code instructions for performing the steps of the method when said program is executed by a computing unit of a navigation device and a processing unit. a control device.

The invention has the advantage of anticipating an acceleration or deceleration of the vehicle to a limit speed operated so as to optimize the energy balance of the vehicle. Advantageously, the invention proposes to provide a system for controlling the speed of a vehicle that is automatic and reliable.

In particular, the invention allows a smarter and more flexible driving made by anticipation. Other advantages and features of the invention will appear better on reading the description of a preferred embodiment which will follow, with reference to the figures, made by way of indicative and nonlimiting example: FIG. schematic diagram of a system for controlling the speed of a vehicle according to this embodiment of the invention;

FIG. 2 is a logic diagram relating to a method of controlling the speed of the vehicle according to this embodiment of the invention;

FIGS. 3A and 4A show examples of curves relating to variations in vehicle speeds on a taxiway comprising a plurality of speed-limiting zones according to this embodiment of the invention;

FIGS. 3B and 4B show examples of curves relating to vehicle acceleration variations according to this embodiment of the invention;

FIG. 3C illustrates an example of a curve relating to the activation of a generator mode of an electric machine as a function of time according to this embodiment of the invention;

FIG. 3D represents an example of a curve relating to a recovery of a kinetic energy of the vehicle as a function of time during a regenerative braking according to this embodiment of the invention;

FIG. 3E represents an example of a curve relating to an electrical energy generated by the electric machine as a function of time during a regenerative braking according to this embodiment of the invention;

FIG. 4C represents an example of a curve relating to the activation of a control device as a function of time according to this embodiment of the invention, and FIGS. 5A and 5B relate to the logic diagrams relating to a regulation step of the method according to this embodiment of the invention. In Figure 1, there is shown an embodiment of the speed control system of a vehicle. This vehicle can be a hybrid or electric motor vehicle, or a motorcycle.

This vehicle is equipped with a powertrain 4 comprising at least one electric machine 3 and associated storage elements, including batteries.

As we have mentioned, this vehicle can be a strictly electric vehicle, or a hybrid vehicle, comprising a heat engine associated with at least one electric machine 3.

This vehicle also comprises rear 9 and front 10 each having two wheels 1 1, 1 2. One of these two trains 9, 10 or both can be coupled to the rotor shaft of the electric machine 3 from 'a differential depending on whether the vehicle is two or four wheels 1 1, 12 drive.

The electric machine 3, the rotor shaft is coupled to one or two trains 9, 10 comprising the wheels 1 1, 1 2 motor and the storage elements form a vehicle energy recovery device. This electrical machine 3 can be connected to the on-board storage elements and is able to operate reversibly in three operating modes. A first operating mode said engine mode in which the electric machine 3 is adapted to exert a driving torque to the wheels 1 1, 12 motor of the vehicle. A second mode of operation said generator mode in which the electric machine 3 is adapted to exert a braking torque on these wheels 1 1, 12 motor, and in particular a regenerative braking energy.

The third mode of operation says freewheel mode in which the electric machine 3 exerts no torque on the wheels 1 1, 12 motor.

The energy recovery device is activated when the electric machine 3 is in the generator mode. Indeed in this configuration, it then performs a regenerative braking that converts the kinetic energy of the vehicle into electrical energy that can be stored and reused later. For example, this stored electrical energy is used when the electric machine 3 operates in motor mode by driving the wheels 1 1, 12 motor vehicle to move and / or accelerate it.

More precisely, the electric machine 3 then functions as an electric generator during the deceleration phases of the vehicle being able to deliver a resistive torque and to deliver to the storage elements an electrical energy resulting from the transformation of the kinetic energy of the dissipated vehicle. during braking.

This powertrain 4, in particular the energy recovery device and therefore the electric machine 3, is placed under the control of the speed control system and more particularly under that of a control device 2. This control device 2 of the powertrain 4 of the vehicle comprises a processing unit 8 corresponding to an advanced control electronics in particular to ensure the management of the electric machine 3 in these three modes of operation. This processing unit 8 comprises at least one processor cooperating with memory elements and is able to execute instructions for the implementation of a computer program. In addition, the control device 2 also makes it possible to control the coordination of the electric machine 3 with other propulsion members of the powertrain 4, for example of the thermal type, when the vehicle is hybrid-propelled. This control device 2 can be connected to:

a module for determining the speed of the vehicle which can comprise at least one speed sensor of the wheels 1 1, 12 motor of the vehicle and / or a speed rotation sensor of the electric machine, and

a module for determining the positive / negative acceleration of the vehicle, such as for example an accelerometer.

The control device 2 is capable, in particular from its processing unit 8, of defining an electric current intensity named here control current I to control the electrical machine 3 of the energy recovery device in these different modes of operation.

Indeed, the electric machine 3 is mechanically linked to the wheels 1 1, 12 motor of the vehicle and is able to generate a magnetic field in the framework of its operation to exercise a braking torque or drive on these wheels 1 1, 1 2 drive.

This magnetic field depends on the architecture of the electric machine 3 and is controlled by the control current I whose intensity is defined by the control device 2 and in particular by its processing unit 8.

Thus, the intensity of this magnetic field is proportional to the intensity of the control current I controlled by the control device 2.

This control device 2 is also capable of receiving information from the speed determination and acceleration / deceleration modules of the vehicle but also a navigation device 1 of the speed control system.

This navigation device 1 is able to exchange information with the control device 2, especially when this control device 2 is controlled by this navigation device 1. The navigation device 1 comprises a location module 5 of the vehicle which can be a satellite geolocation module (GPS acronym for Global Positioning System) or any equivalent location module. This locating module 5 is capable of delivering geographical positioning data of the vehicle, in latitude and longitude.

In a first variant, this location module 5 can implement a cellular location or also called "cell-id" location that uses the mobile cellular network to geolocate by triangulation via the relay antennas of this network the vehicle when the device navigation 1 comprises a communication module 6 compatible with such a network. This cellular localization can allow to locate the vehicle especially in places where GPS coverage is low or nonexistent, such as under a tunnel.

In a second variant, this location module 5 can also implement a location from Wifi technology when the communication module 6 of this navigation device 1 is compatible with such a technology, by ensuring this location from the recognition of known identifiers of Wifi terminals located in the vehicle environment. These identifiers corresponding for example to the MAC addresses (acronym for "Media Access Control") of these terminals.

In a third variant, this location module 5 can also implement a location from beacons positioned on the taxiway and an identification module of these tags connected to the location module 5. Thus identifying these tags the locating module 5 is able to determine the location of the vehicle on the taxiway. The locating module 5 can implement one or the other of these variants or a combination thereof to accurately determine the position of the vehicle on the taxiway.

It also includes a storage module 6 for archiving including mapping data. This mapping data relates to information needed to move the vehicle in its environment.

This information concerns, for example, communication routes, such as road networks and all information and all the characteristics relating to them, including limit speeds in force at different zones defined on these communication channels or on the topography relative to the environment in which the vehicle operates. The storage module 6 may for example be a high capacity memory, typically of the order of one gigabyte.

The navigation device 1 also comprises a calculation unit 7 which is able from the mapping data and the geographical location data to accurately determine the location of the vehicle on the taxiway and its direction of travel on the latter. . This calculation unit 7 comprises at least one processor cooperating with memory elements. This calculation unit 7 is able to execute instructions for the implementation of a computer program.

As we have seen, this navigation device 1 comprises a communication module 6 enabling it to exchange data with the control device 2 but also with a server and / or a removable data medium (for example a USB key , hard disk, memory card, digital optical disk, etc.) with mapping data.

This communication module 6 can then enable the navigation device 1 to exchange these mapping data with this server and / or this data carrier via a wireless transmission made for example from a cellular network. or satellite or even technologies like Bluetooth or NFC (Near Field Communication, translated by communication in the near field) or Wifi. Alternatively, this transmission can be wired. Indeed, the server can be connected to an Ethernet type network or the data carrier can be connected to the navigation device 1 according to USB technologies (acronym for Universal Sériai Bus which means in French universal bus in series) or FireWire ™. When the data medium is removable as a memory card or a digital optical disk, this communication module 6 includes a reading unit compatible with each of these different media. It will be noted that the navigation device 1 can thus connect to the server via the Internet through various wired and / or wireless networks mentioned above.

Thus, the mapping data stored in the storage module 6 can from this communication module 6 be updated regularly by being downloaded from the server and / or the data medium. These mapping data are always in accordance with the environment in which the vehicle is to evolve and also with the legislation in force in particular as regards the speed limits relating to different areas of a taxiway.

It will be noted that this navigation device 1 is also able to provide a vehicle guidance function between its instantaneous position and a destination chosen by the driver.

The navigation device 1 also comprises a man-machine interface compotant a display module and control elements. These control elements can be separate from the display module (in the case of controls at the wheel of a vehicle, a remote control, a keyboard, etc.), to be an integral part (case of the touch screen), or be a combination of these two possibilities. They are preferably operated by a user.

Thus, the vehicle driver can activate / deactivate the vehicle speed control system from these control elements.

This navigation device 1 can also be connected to the speed determination module 13 of the vehicle and / or to the acceleration / deceleration determination module 14 of the vehicle either directly or through the control device 2.

In addition, the navigation device 1 can also be connected by the multiplex network of the vehicle to the electronic control units of the latter which are capable of delivering information relating to the condition of the traffic lane on which it travels.

Such units correspond, for example, in a non-exhaustive and nonlimiting manner to an electronic injection computer, a computer of the dashboard, to brake control units such as the anti-lock of the ABS wheels (English acronym for "Antilock Brake System"), the anti-skating ESP (acronym for "Electronic Stability Program") or the ASR trajectory control (English acronym for "Anti Split Regulation") or a dynamic driving control computer. This navigation device 1 can also be connected to sensors located in the vehicle. For example, sensors operating detection of wipers reflecting the phenomena of rain, various fires likely to be lit according to the ambient light or weather phenomena, such as low beam at night or fog lights.

The speed control system of a motor vehicle is capable of implementing a method for controlling the speed of said vehicle, the principle of which is described by the flow diagram of FIG. 2. This method makes it possible to control the speed V1 of the vehicle in adapting it progressively and in advance to limit speeds V2 or V3 in force respectively on zones B or C of the taxiway on which the vehicle is traveling. Such a variation of the speed of the vehicle on the zones A, B or C is described by the curve illustrated in FIG. 4A and also by the curve represented in FIG. 3A which relates more specifically to the zone A of this traffic lane.

To do this, this method may comprise a preliminary step of updating the mapping data included in the storage module 6. Indeed, the navigation device 1 is able to connect to the server and / or the data carrier of the data storage module. so as to verify that the mapping data included in the storage module 6 are up to date and if this is not the case to perform this update. Such updated mapping data may relate in a nonlimiting and non-exhaustive manner, the topography of the environment in which the vehicle is evolving or will evolve, as well as the limiting speeds V2, V3 of these zones B, C which may be brought to change. However, this updating step can also be performed at any time, for example as soon as a modification of the mapping data archived on the server has occurred. In addition, the navigation device 1 is also able to modify the mapping data as a function of events present in the vehicle environment and which may have an effect on the limit speed V2, V3 in effect on the zone. B, C of the taxiway.

Such events may involve road traffic, roadway work or other interventions, or changes in weather conditions.

In this way, the speed limits relating to predefined zones B, C of communication channels included in the immediate environment and / or the future of the vehicle correspond to those which are legally in force at the moment the vehicle crosses these different zones. B, C.

This method provides a step of estimating the location of the vehicle when it circulates on the taxiway. Indeed, the navigation device 1 determines geographical coordinates, latitude and longitude, relative to the positioning of the latter on the A or B areas of this lane. These coordinates are then archived in the storage module 6 of the device in order to be transmitted in particular to the computing unit 7. This calculation unit 7 then performs a correlation operation between these coordinates and the mapping data archived in the storage module 6. Thus, in the example illustrated in FIGS. 3A and 4A, where the vehicle is traveling at zone A of the taxiway, this calculation unit 7 then determines the location of the vehicle at time t0. The position of the vehicle being determined, this method then provides a step of predicting a zone 16 of the driving lane providing a speed limitation and being on the path followed by the vehicle.

To do this, the calculation unit 7 identifies from the mapping data the different zones B, C of this lane having a speed limitation V2, V3 which is different than that in force on the zone A crossed by the vehicle. at the instant tO.

Among the zones B, C identified, the calculation unit 7 then determines a zone B which must be crossed by the vehicle as well as the speed limit V2 relative to this zone B which must be respected by the vehicle during the crossing of this area B.

This zone B is contiguous to the zone A extending in the continuity of the latter in the direction of circulation of the vehicle.

The navigation device 1, more precisely the calculation unit 7, being connected to the speed determination module 13 also evaluates the speed V1 of the vehicle at the instant t0 during a determination step 17 of the speed V1 of the vehicle. vehicle.

As illustrated in FIG. 4A, this speed V1 can be determined by performing a sampling D of measurement of the speed in a given time interval. Thus, a predetermined number of measurements of the speed deemed sufficient to obtain an accurate measurement of this speed V1 is then performed in this time interval. The calculation unit 7 then carries out a comparison step 18 of the vehicle speed V1 with the speed limit V2 in effect on this zone B of the taxiway.

When this vehicle speed V1 is greater than the limit speed V2, the navigation device 1 then carries out a step of evaluating the distance d0 to be traveled extending from the position of the vehicle at the instant t0 to the entry of zone B at time t2, with reference to FIG. 4A.

This distance d0 is evaluated from the determination of the position of the vehicle at time t0 and mapping data relating in particular to the area A of the driving lane. In this context where the speed V1 is greater than the limit speed V2, the method then provides a step of determining a negative acceleration constant G1, implemented by the calculation unit 7 and to allow to decelerate the vehicle so that it goes from a speed V1 to a speed V2 by crossing the entry of the zone B at the moment t2 as illustrated by the curve defining this change of speed of the vehicle in FIGS. 3A and 4A when a such negative acceleration G1 defined by the curve of FIGS. 3B and 4B is applied to the vehicle between times t1 and t2. This negative acceleration constant G1 is pre-calculated and stored in the storage module 6 of the navigation device 1. This negative acceleration constant G1 is defined according to technical criteria of the vehicle, that is to say in a non-exhaustive and non-limiting manner according to, for example, its resistance to advancement, its mass, its category (industrial, family vehicle). or sports). Subsequently, the method provides an evaluation step 19 of a timing t1 launching this deceleration of the vehicle and a step of determining a distance d1 on which the vehicle will be decelerated.

These evaluation step 1 9 of the time t1 and determination of the distance d1 are implemented by the calculation unit 7 which is able to execute an algorithm implementing the following equations: for the evaluation determination of the moment t1: t = (V _f - V,) / G

with:

^■ t the moment t1 when the deceleration of the vehicle is triggered;

^■ G the negative acceleration constant G1;

^■ V, the speed V1 of the vehicle, and

■ V _f the speed limit V2 in force in zone B.

for the distance determination d1: d = (V _f ² - V, ² ) / 2. G

with:

^■ d the distance d1 deceleration between t1 and t2;

■ G the negative acceleration constant G1;

^■ V, the speed V1 of the vehicle, and

^■ V _f the speed limit V2 in force in zone B.

At time t1, the navigation device 1 interacts with the control device 2 of the power unit 4, and during a transmission step 20 sends the latter a braking instruction.

Thus at this moment t1, the control device 2 is then activated and controlled by the navigation device 1 as shown in the curve of FIG. 4C. It will be noted that this control device 2 is activated by the navigation device 1 when it is necessary to apply to the vehicle acceleration or deceleration. This control device 2 is activated until the vehicle reaches the speed limit V2 in force at zone B.

The braking setpoint is generated by the calculation unit 7, in particular from data relating to the negative acceleration constant G1. It then consists of a request comprising this negative acceleration constant G1 which the vehicle will have to follow in order to reach the limit speed V2 at time t2. This braking setpoint is linked to a control setpoint for the magnetic field of the electric machine 3.

On the basis of this braking instruction, the method provides for an activation step 21 of the electric machine 3 of the energy recovery device, in electric generator mode, by the control device 2 and in particular by its processing unit 8 .

As illustrated by the curve relating to the activation of the generator mode of the electric machine with respect to time in FIG. 3C, this generating mode of the electric machine is activated from instant t1 to t2 over the entire distance d2 of deceleration of the vehicle and therefore until the latter reaches the speed limit V2. The processing unit 8 then determines, during a calculation step 22, the control current I to control the energy recovery device and therefore the electric machine 3.

To do this processing unit 8 executes an algorithm implementing the following equation:

I = C / KE _m with:

^■ C corresponds to the braking torque to be applied to the wheels 1 1, 12 motor of the vehicle;

^■ K is a constant relating to the mechanical and electrical architecture of the electrical machine 3, and

^■ E _m the magnetic field of the electric machine 3.

The torque C corresponding here to the braking torque which is almost similar to the torque of the electric machine 3 is determined from the following equation:

C = R.ratio.F

with:

^■ R the radius of a wheel 1 1, 12 driving the vehicle;

^■ ratio relates to the gear ratio corresponding to the ratio between the speed of rotation of the electric machine 3 and the speed of rotation of the wheel axis;

^■ F a force, here the braking force, according to the braking setpoint defining the negative acceleration constant G1 to be respected.

This braking force is defined by the following equation:

F = g. Mr. G

with:

^■ the acceleration of gravity;

■ M the mass of the vehicle, and

^■ G the negative acceleration constant G1.

Thus, the control device 2 determines the control current I of the energy recovery device, more particularly its intensity, as a function of the negative acceleration constant G1. This intensity of control current I is proportional to the intensity of the magnetic field of the electric machine 3.

The electric machine 3 in generator mode will therefore generate a magnetic field which will therefore generate a resistive torque. This resisting torque, which is then proportional to the magnetic field, is correlated with the braking torque which will make it possible to carry out the deceleration of the vehicle up to the limit speed V 2. It is understood that such a deceleration of the vehicle is performed without the hydraulic braking system of the vehicle is solicited.

By performing this deceleration, the electric machine 3 performs a regenerative braking of the vehicle to charge the storage elements with electrical energy.

Indeed, the electric machine 3 being in generator mode, the mechanical energy restored by the wheels 1 1, 1 2 through the transmission axis drives the electric machine 3 and generates a magnetic field converted into electrical energy.

As a result, the vehicle is then braked using the electric engine operating as a generator between times t1 and t2. Between these instants t1 and t2, the kinetic energy recovered by the braking defined by the curve shown in FIG. 3D is converted into electrical energy to be stored as shown in the curve of FIG. 3E, which improves the overall energy efficiency of the rolling vehicle. It will be noted that the higher the control current I, the more powerful the regenerative braking and the greater the electrical energy restored. When performing the deceleration of the vehicle, the method provides a step 23 closed loop control of the negative acceleration constant G1 by controlling the electric machine 3 according to the principle defined in Figure 5A. This regulation step 23 is performed by the control device 2 and in particular by the processing unit 8.

Indeed, this control device 2 makes it possible to reach and maintain a braking torque applied to the wheels 1 1, 1 2 of the vehicle as a function of the braking set point. As we have seen, this braking setpoint defines a negative acceleration constant G1 described by the curve C1 of FIG. 3B.

To do this, the control device 2 implements a PID correction algorithm (acronym for "Proportional Integral and Derivative") to subsequently deliver a control signal from the difference between the acceleration constant negative G1 defined by the braking setpoint and a realized measurement of the negative acceleration G1 'of the vehicle.

More specifically, the control device 2 by executing this algorithm performs, at a given instant, a physical measurement of the negative acceleration G1 'of the vehicle defined by the curve C2 in FIG. 3B and compares it with the acceleration constant. negative G1 of the braking setpoint. This physical measurement of the negative acceleration G1 'of the vehicle can be obtained by the control device 2 from the module of determination of the acceleration 14 of the vehicle or again from the navigation device 1 whose calculation unit 7 is able to determine such a measurement by carrying out particular operations on the basis of information delivered by the locating module 5 and which relate to the movement and location of the vehicle at different successive times.

If the negative acceleration G1 'measured is different from the negative acceleration constant G1, the control device 2 and therefore the processing unit 8 then proceeds to the correction of the braking torque supplied by the electric machine 3 by increasing or decreasing the intensity of the control current I.

If, conversely, the negative acceleration G1 'measured is substantially equal to the negative acceleration constant G1, the processing unit 8 authorizes the continuation 24 of the deceleration of the vehicle by not making any correction of the braking torque. supplied by the electric machine 3.

Thus, this deceleration of the vehicle then continues according to the negative acceleration constant G1 defined by the braking setpoint.

This regulation 23 of the negative acceleration constant G1 is carried out until the vehicle reaches the limit speed V2. Such a regulation 23 makes it possible to overcome the impact that geographical inclination fluctuations, vehicle mass, passive resistances, drifting machines and energy storage can have.

Note that we mean by:

- passive resistances: the forces that are likely to hinder the movement of the vehicle; - Drifting machines: the resistant forces resulting from the age of the electric machine 3 and / or the evolution of the efficiency of the electric machine 3 in generator mode mainly as a function of the internal temperature and the evolution over time the molecular structure of the materials that compose it, such as copper;

- energy storage: the evolution over time of the chain of control and regulation of the recharge of storage elements that can become obsolete and have a declining yield. In addition, during this deceleration of the vehicle the control device 2 may trigger the automatic ignition of the brake lights if the deceleration caused during this regenerative braking is too strong.

The regenerative braking management by the navigation device 1 is virtually transparent to the driver who will have a substantially constant braking level whatever the nature of the hybrid or electric powertrain 4.

It should be noted that the system for controlling the speed of a vehicle by thus performing a regenerative braking energy, performed in advance to decelerate the vehicle to a limit speed, optimizes the energy balance of this vehicle.

Once the speed limitation zone V2 reached by the vehicle at time t2, the navigation device 1 no longer interacts with the control device 2 of the powertrain 4 as illustrated by the curve relating to the activation of this control device 2 as a function of the time defined in FIG. 4C. At time t2, the control device 2 activates the motor mode of the electric machine 3 and maintains the speed V1 of the vehicle at the speed V2. Note that if at time t2 the vehicle speed V1 is equal to the limit speed V2 and the negative acceleration constant G1 is zero, the control device 2 activates the engine mode or the freewheel mode of the machine Electric 3.

When the vehicle is traveling on the zone B of the taxiway, between the time t2 and t3, the navigation device 1 performs different operations including determining the location of the vehicle and identifying the next zone C with a speed limit V3 different from the limit speed V2 of the zone B where the vehicle is traveling.

To do this in the example illustrated in FIG. 4A, where the vehicle is traveling at zone B of the taxiway, at time t3 the method provides for a step of estimating the location of the vehicle intended to determine the geographical coordinates of the vehicle and correlate them with the mapping data included in the memory elements of the navigation device 1. Once the position of the vehicle is established, the zone C with a speed limitation V3 and which is on the path followed by the vehicle is then determined during the prediction step 16.

With reference to the curve relating to the speed of the vehicle illustrated in FIG. 4A, between times t2 and t3 the vehicle traveling on zone B of the traffic lane has a speed V1 which corresponds to the limit speed V2.

This speed V1 and thus the speed limit V2 is then compared with the speed limit V3 in force at zone C of the taxiway. Such a comparison step 18 of these speeds V1 and V3 is implemented by the calculation unit 7 of the navigation device 1. When the speed V1 of the vehicle is lower than the speed limit V3 the navigation device 1 and in particular the calculation unit 7, implements a step of determining a positive acceleration constant G2 which is pre-calculated and stored in the storage module 6 of this navigation device 1. As for the negative acceleration constant G 1, the acceleration constant G 2 is defined according to the technical criteria of the vehicle.

The method then provides a step 19 for evaluating an instant t3 for launching the acceleration of the vehicle, which corresponds here to the moment when the vehicle traveling at constant speed V2 leaves zone B. This moment t3 is determined by calculation by the calculation unit 7 of the navigation device 1 from the distance d2 relative to the zone B and the limit speed V2 in effect on this zone B. Thereafter, the method comprises a step of determining a distance d3 on which the vehicle will be accelerated.

This step of determining the distance d3 is performed by the computing unit 7 which is able to execute an algorithm implementing the following equation: d3: d = (V, ² -Vi ² ) / 2.G

with:

^■ d the acceleration distance d3 between instants t3 and t4;

■ G the positive acceleration constant G2; ^■ V, the vehicle speed V1 which is equal to V2 between times t2 and t3, and

^■ V _f the speed limit V3 in force in zone C. At time t3, the navigation device 1 interacts with the control device 2 of the powertrain 4, and during a transmission step 20 sends to the latter an acceleration instruction.

Thus at this time t3, the control device 2 is then activated and controlled by the navigation device 1 as illustrated by the curve defining the activation of this control device with respect to time in FIG. 4C.

This control device 2 is activated until the vehicle reaches the speed limit V3 in force at zone C.

The acceleration instruction is generated by the calculation unit 7, in particular from data relating to the positive acceleration constant G2. It then consists of a request comprising this positive acceleration constant G2 that the vehicle will have to follow in order to reach the limit speed V3 at time t4. This acceleration setpoint is linked to a control setpoint for the magnetic field of the electric machine 3.

On the basis of this acceleration instruction, the method provides for an activation step 21 of the electric machine 3 in motor mode, by the control device 2 and in particular by its processing unit 8.

This motor mode of the electric machine is activated from time t3 to t4 over the entire acceleration distance d3 of the vehicle and therefore until the latter reaches the speed limit V3. The processing unit 8 then determines, during a calculation step 22, a control current I for controlling said electric machine 3.

To do this, the control device 2 executes an algorithm implementing the following equation:

I = C / K.Em

with:

^■ C corresponds to the driving torque to be applied to the wheels 1 1, 12 motor of the vehicle;

A constant relating to the mechanical and electrical architecture of the electric machine 3;

^■ Em the magnetic field of the electric machine 3.

The torque C corresponding here to the driving torque which is almost similar to the torque of the electric machine 3 and is determined from the following equation:

C = R.ratio.F

with:

^■ R the radius of a wheel 1 1, 12 driving the vehicle;

■ ratio relates to the gear ratio corresponding to the ratio between the speed of rotation of the electric machine 3 and the speed of rotation of the wheel axis;

^■ a force F, by the acceleration force according to the acceleration setpoint defining the constant positive acceleration G2 to be observed.

This acceleration force is defined by the following equation:

F = g. Mr. G

with:

- the acceleration of gravity;

^■ M the mass of the vehicle, and G the positive acceleration constant G2.

Thus, the control device 2 determines an intensity of the control current I as a function of the positive acceleration constant G2 which is proportional to the intensity of the magnetic field of the electric machine 3.

The electric machine 3 in motor mode will therefore generate a magnetic field that will generate a driving torque and thus allow the vehicle to accelerate until its speed V1 reaches the limit speed V3.

Thus, the control device 2 determines the control current I, more particularly its intensity, as a function of the positive acceleration constant G2. This intensity of the control current I is proportional to the intensity of the magnetic field of the electric machine 3.

The electric machine 3 in engine mode will therefore generate a magnetic field which will generate a motor torque. This motor torque, which is then proportional to the magnetic field, is then correlated with the driving torque which will make it possible to accelerate the vehicle to the limit speed V3.

When carrying out the acceleration of the vehicle, the method provides in the same manner as during the deceleration of the vehicle, a closed-loop regulation step 23 of the positive acceleration constant G2 by slaving the electric machine 3 according to the principle defined in Figure 5B. This regulation step 23 is performed by the control device 2 and in particular by the processing unit 8. Indeed, this control device 2 makes it possible to reach and maintain a driving torque of the wheels 1 1, 12 of the vehicle as a function of the acceleration set point. As we have seen, this acceleration setpoint defines a positive acceleration constant G2 described by the curve of FIG. 4B between the instants t3 and t4.

To do this, the control device 2 implements a PID correction algorithm (acronym for "Proportional Integral and Derivative") to subsequently deliver a control signal from the difference between the acceleration constant positive G2 defined by the acceleration instruction and a measurement of the positive acceleration G2 'of the vehicle.

More specifically, the control device 2 by executing this algorithm regularly performs at a given instant a physical measurement of the positive acceleration G2 'of the vehicle and compares it with the positive acceleration constant G2 of the acceleration setpoint.

If the measured positive acceleration G2 'is different from the positive acceleration constant G2, the control device 2 and therefore the processing unit 8 then proceeds to the correction of the driving torque supplied by the electric machine 3. increasing or decreasing the control current I. If conversely, the measured positive acceleration G2 'is substantially equal to the positive acceleration constant G2, the processing unit 8 authorizes the continuation 26 of the acceleration of the vehicle by not making any correction of the driving torque supplied by the electric machine 3. Thus this acceleration of the vehicle then continues according to the positive acceleration constant G2 defined by the acceleration setpoint. This regulation 23 of the positive acceleration constant G2 is carried out until the vehicle reaches the limit speed V3. Complementarily, between instants t3 and t4, the navigation device 1 can define a progressive speed ramp during a calibrated time to avoid a sudden acceleration of the vehicle during the passage of the electric machine 3 in engine mode. Once the speed limitation zone C V3 reached by the vehicle at time t4, the navigation device 1 no longer interacts with the control device 2 of the powertrain 4 as illustrated by the curve relating to the activation of this control device 2 as a function of the time defined in FIG. 4C.

When the vehicle is traveling on the area C of the traffic lane, the navigation device 1 determines from the location of the vehicle and the mapping data the next area that is likely to be crossed by the vehicle and whose speed limit is different from that of the area where the vehicle is traveling, here zone C, in order to anticipate acceleration or deceleration of the vehicle.

The invention thus makes it possible to anticipate in advance the adaptation of the speed of the vehicle to a limit speed by allowing, for example, a gradual and optimal braking of the vehicle well before the speed limit zone, thereby reaching the limit speed.

The invention may find a particular application also for vehicles comprising an energy recovery device comprising a hydraulic machine instead of an electric machine. In this case, the braking and acceleration instructions for controlling the current control I of the electric machine 3 will be adapted to control a control pressure.

The invention can also be implemented in an environment in which there is an intense traffic of vehicles. This is the case, for example, in mining or open pit quarries or loading or unloading docks in port or airport areas. In such cases the rigors of the traffic regulations are found under the authority of the company or company in charge of the operation. Therefore, the navigation control of the vehicle and the mapping data will be adapted according to the internal regulations of these companies or companies.

The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof within the scope of the claims below.

Claims

1. A method for controlling the speed (V1) of a vehicle, in particular an electric or hybrid vehicle, capable of running on a traffic lane, characterized in that it comprises the following steps:

- estimate (15) of the location of the vehicle on the taxiway;

prediction (16) according to the location of the vehicle of an area (B) of the traffic lane comprising a limit speed (V2) that is likely to be traversed by said vehicle, and

determination of a control current (I) of an energy recovery device enabling the vehicle to reach said limit speed (V2) at the input of said zone (B) when the vehicle speed (V1) is greater than said limit speed (V2).

2. Method according to the preceding claim, characterized in that the step of determining the control current (I) provides:

a determination of a negative acceleration constant (G1) of the vehicle;

an evaluation (19) of the instant (t1) of launching a deceleration of the vehicle over a distance (d1) to be traveled before reaching zone (B), and

a calculation (22) of the control current (I) as a function of the negative acceleration constant (G1).

3. Method according to the preceding claim, characterized in it comprises an activation step (21) of a generator mode of an electric machine (3) included in the energy recovery device, said electric machine (3) being able to perform a regenerative braking of energy during the deceleration of the vehicle so that said vehicle reaches the speed limit (V2) at the entrance to the zone (B).

4. Method according to any one of the preceding claims, characterized in that it comprises a step of determining a control current (I) enabling the vehicle to reach a limit speed (V3) at the input of a next zone (C) when the speed (V1) of the vehicle is lower than this limit speed (V3), said step of determining a control current (I) providing for:

a determination of a positive acceleration constant (G2) of the vehicle;

an evaluation (19) of an instant (t3) corresponding to the output of the speed limiting zone (B) (V2) in which the vehicle is traveling in order to launch a deceleration of the vehicle over a distance (d3) to go before reaching the next zone

(C), and

calculating (22) the control current (I) as a function of said positive acceleration constant (G2).

5. Method according to any one of claims 2 to 4, characterized in that it comprises a step of regulating (23) the acceleration or deceleration of the vehicle.

6. Method according to any one of the preceding claims, characterized in that the step of estimating (1 5) the location of the vehicle provides a determination of coordinates geographical position of the vehicle on the taxiway.

7. Method according to any one of the preceding claims, characterized in that the prediction step (16) provides a correlation of geographical coordinates relating to the position of the vehicle with mapping data for the determination of the area (B, C) of the taxiway with a limit speed (V2, V3).

8. A system for controlling the speed of a vehicle, in particular an electric or hybrid vehicle, capable of running on a taxiway and comprising a device for recovering energy, the system comprising a navigation device (1) and a control device (2) for the energy recovery device, characterized in that the navigation device (1) is able to locate said vehicle on the taxiway and to identify a zone (B) of this taxiway which is capable of being traversed by said vehicle, said navigation device (1) being able to interact with the control device (2) so as to determine a control current (I) of the energy recovery device enabling the vehicle to reach a speed limit (V2) at the entry of said zone (B) when the speed (V1) of the vehicle is greater than the speed limit (V2).

9. System according to the preceding claim, characterized in that the energy recovery device comprises an electric machine (3).

10. System according to any one of claims 8 and 9, characterized in that the navigation device (1) comprises a locating module (5) and is able to cooperate with modules for determining the speed (13) and the acceleration / deceleration (14) of the vehicle.

1 1. System according to any one of claims 8 and 10, characterized in that the navigation device (1) comprises a storage module (6) archiving mapping data including in particular speed limits (V2, V3) zones (B , C) of the taxiway.

Vehicle, in particular an electric or hybrid vehicle, comprising a speed control system (V1) according to any one of claims 8 to 11.

A computer program comprising program code instructions for performing the steps of the method according to claims 1 to 7 when said program is executed by a computing unit (7) of a navigation device (1) and a processing unit (8) of a control device (2).