FR3138095A1 - Motor vehicle braking curve mapping - Google Patents

Abstract

The subject of the invention is a motor vehicle braking assembly (2) comprising: a first braking system; an accelerator control movable from a return position; a rotating electric machine (20) driving the motor vehicle; a control unit (30) of the rotating electric machine configured so that when the accelerator control (16) is in the return position the rotating electric machine generates a first braking torque. The braking assembly further comprises means (26) for detecting a faulty mode of the first system. The control unit is configured so that in fault mode, in the return position, the rotating electric machine generates a second braking torque greater than the first braking torque. The control unit then adopts a braking map with an increased braking level by default. Figure to be published with the abstract: Fig. 1

Description

Automotive vehicle braking curve mapping

The invention relates to the field of vehicle braking. More specifically, the invention relates to the braking of a motor vehicle by a rotating electric machine capable of recovering energy during braking phases. The invention also provides a motor vehicle with a braking assembly and a method of braking a motor vehicle.

An electric motor vehicle has one or more rotating electrical machines. These machines are able to propel the vehicle, but also to brake it. This improves the safety of the vehicle and reduces the strain on the friction braking system. Optionally, during a braking phase, the electric machine recovers energy in order to recharge the vehicle's electric battery. In this way, the vehicle's range is extended, and the need for primary energy is reduced.

A motor vehicle commonly has a friction braking system. Such a system has an annular surface secured to a wheel, and a pad cooperating by friction with the annular surface in order to dissipate the kinetic energy of the vehicle. The force with which the pad is pressed against the annular surface is adjusted by the driver. However, the kinetic energy of the vehicle commonly reaches significant levels that require a high braking force; and which would be too high for the physical capacities of an average driver. This is why, in order to multiply the driver's effort, the vehicle has a brake assist that amplifies his physical action on the brake control. Thus, the driver obtains a maximum deceleration of the order of 10 m/s2 by applying a force of the order of 15 daN. Without the brake assist, the force to be provided would be of the order of 100 daN.

The brake assist is exposed to the risk of technical failures, so that the driver no longer benefits from the braking assistance. Only his own strength allows him to brake the vehicle. This may prove insufficient in the event of emergency braking, or for braking at high speed. The mass of the vehicle and a downhill road further increase the effort required by the driver.

The torque received by a vehicle wheel is dictated by a predefined mapping. A drive wheel receives an engine torque that increases with the depressing of the accelerator pedal. Conversely, this same wheel receives a braking torque that gradually increases with the depressing of the brake pedal. Thus, the wheel receives a continuously defined torque for each position of the pedals.

For safety reasons, some vehicles are programmed so that when no pedal is pressed, i.e. when they are each in their rest position, a braking torque is generated. This default braking torque prioritizes energy recovery and safety since the vehicle tends to slow down without any action from the driver. When the vehicle is parked, pressing the accelerator higher than a predefined level is necessary for the vehicle to start moving.

However, the safety level of such a vehicle remains improvable. In the event of a failure of the friction braking system, the effort required by the user remains significant. Certain braking levels remain unattainable, and the vehicle's stopping times are particularly long.

Document EP3623242A1 discloses an electric motor vehicle, provided with a control system. The electric vehicle comprises a main power supply for the propulsion of the electric vehicle and a braking power supply for the braking actuators. The control system comprises a propulsion control unit for controlling propulsion actuators, and at least one brake control unit for controlling at least one of the braking actuators. The propulsion control unit is further configured to control one or more propulsion actuators to perform emergency braking in the event of detection of a failure of the braking system. However, the safety level of this vehicle remains improvable.

The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to propose a motor vehicle braking assembly that improves safety. The invention also aims to optimize the functionality and safety of a motor vehicle.

According to a first aspect, the invention proposes a motor vehicle braking assembly comprising: a first braking system; an accelerator control intended to be moved by a user from a return position; a rotating electrical machine capable of driving the motor vehicle as a function of a movement of the accelerator control; a control unit of the rotating electrical machine configured so that when the accelerator control is in the return position the rotating electrical machine generates a first braking torque; remarkable in that the braking assembly further comprises means for detecting a fault mode of the first braking system, the control unit being further configured so that in fault mode, when the accelerator control is in the return position, said control unit controls the rotating electrical machine so that it generates a second braking torque greater than the first braking torque.

Preferably, the first braking system comprises a braking control and a device for assisting actuation of the braking control, the control unit is configured to control the rotating electrical machine so that it generates the second braking torque when the detection means detect a failure of said actuation assistance device.

Preferably, the braking control is intended to be moved by the user from a neutral position, the control unit is configured to control the rotating electrical machine so that it generates the second braking torque when the braking control is in the neutral position.

Preferably, the braking control is able to be moved from the return position to a reference position; when the braking control is moved to the reference position, in faulty mode and in normal mode of the first braking system, the control unit is configured to control the rotating electrical machine so that it generates a third braking torque greater than the second braking torque.

Preferably, the means for detecting a faulty mode of the first braking system are configured to perform a comparison between a measured braking value and a set braking value corresponding to a user braking instruction, the braking value being a brake fluid pressure or a deceleration.

Preferably, the control unit (30) is configured so as to detect the fault mode when the measured braking value is less than or equal to 80%, preferably 60%, of the braking value.

Preferably, the accelerator control is capable of traveling through a predefined movement zone in which, when the first braking system is in normal mode, then the control unit is configured so as to control the rotating electrical machine so that it generates an acceleration torque; and when the first braking system is in faulty mode then the control unit is configured so as to control the rotating electrical machine so that it generates a braking torque when the accelerator control is in said predefined movement zone.

Preferably, the control unit is configured so as to control the rotating electrical machine so that it generates an acceleration torque as a function of a movement of the accelerator control multiplied by a multiplier coefficient; in fault mode the multiplier coefficient is a first coefficient, and in normal mode the multiplier coefficient is a second coefficient lower than the first coefficient.

Preferably, the accelerator control is capable of being moved in a first movement range; when the accelerator control is in the first movement range, the control unit is configured to control the electric machine so that it generates an acceleration torque outside the faulty mode, and so as to generate a braking torque when the detection means detect a faulty mode.

Preferably, the first braking system is a friction braking system.

Preferably, the recall position is a start of stroke position.

Preferably, the second braking torque is configured so as to generate a deceleration of the vehicle of between 2 m/s2 and 5 m/s2.

Preferably, the first braking torque is configured so as to generate a deceleration of the vehicle of between 0.1 m/s2 and 1 m/s2.

Preferably, the detection means comprise a pressure sensor of a hydraulic braking circuit and/or a pressure sensor of the assistance for the actuation of a braking control.

Preferably, the rotating electric machine is coupled to a wheel.

According to another aspect, the invention proposes a motor vehicle braking assembly comprising: a first braking system comprising a braking control with assistance for actuation of the braking control; means for detecting a faulty mode of the actuation assistance; a rotating electrical machine capable of driving the vehicle; an accelerator control intended to be moved by a user from a return position in order to control the electric machine; remarkable in that the braking assembly further comprises a control unit for the rotating electrical machine which is configured such that, when the detection means detect a failure of the actuation assistance, the rotating electrical machine generates a braking torque so as to slow down the motor vehicle; preferably over a range of movement of the accelerator control.

According to another aspect of the invention, the invention proposes a motor vehicle braking assembly comprising: a first braking system; means for distinguishing a faulty mode from a normal mode of the braking system; a rotating electrical machine capable of driving the motor vehicle as a function of an accelerator command from a user; a control unit configured so that in normal mode the rotating electrical machine generates a first level of braking assistance; remarkable in that in faulty mode of the first braking system, the control unit is configured to control the rotating electrical machine so that it generates a second level of braking assistance greater than the first level of assistance.

Preferably, the detection means are configured to distinguish a nominal operating mode from a faulty mode in which the detection means detect a failure of the first braking system.

According to another aspect, the invention proposes a motor vehicle comprising a braking assembly, remarkable in that the braking assembly is in accordance with the invention, and in that the motor vehicle comprises an electric drive accumulator, the rotating electric machine is capable of recharging the electric drive accumulator.

According to another aspect, the invention proposes a method for braking a motor vehicle comprising a braking assembly, characterized in that the braking assembly is in accordance with the invention; the method comprising the following steps: detection of the accelerator control in the return position; generation of the first braking torque by the rotating electrical machine; reception of a failure signal from the first braking system; then generation of the second braking torque by the rotating electrical machine.

Preferably, the method further comprises a step of actuating the first braking system so as to generate a primary braking torque; said primary braking torque being added to the second braking torque.

Preferably, at the stage of generating the second braking torque, the rotating electrical machine recovers a second quantity of electrical energy greater than a first quantity of recovered electrical energy.

According to another aspect, the invention provides a computer program comprising code instructions, which when executed by a calculator or a computer, make it possible to carry out a braking method according to the invention.

According to another aspect, the invention provides a computer-readable recording medium comprising instructions which, when executed by a computer, cause the latter to implement the steps of the braking method according to the invention.

The invention, through the control unit, then adopts a braking map with an increased braking level by default. Thus, the safety of the vehicle is increased since the default deceleration of the vehicle increases. The management of the vehicle speed is simpler since it is easier to immobilize it.

The invention will be well understood and other aspects and advantages will appear clearly on reading the following description given with reference to the figures annexed and listed below.

There is a top view of a motor vehicle with a braking assembly according to the invention.

There illustrates braking maps of a braking assembly of a motor vehicle; in fault mode and in normal mode according to the invention

There is a diagram of a braking method of a braking assembly of a motor vehicle according to the invention.

In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows the presence of other elements in the motor vehicle or other steps in the method to which it relates. It is understood that the term "comprise" includes the terms "consist of". The terms "external" and "internal" will designate respectively that which is oriented towards the outside of the vehicle and towards the inside of the vehicle.

In this description, the term “longitudinal”, the term “longitudinally”, the term “transverse”, and the term “transversely” are used according to the reference frame of the vehicle, in the mounting configuration. The term “longitudinal” corresponds to the main direction of movement of the vehicle. The term “transverse” corresponds to a direction perpendicular to the main direction of movement of the vehicle. The term “front” refers to the main direction of movement of the vehicle. The term “rear” designates the opposite of the front of the vehicle. The X axis represents the longitudinal direction, the Y axis represents the transverse direction, and the Z axis represents the vertical direction.

In this description, the value ranges include the limits which delimit them.

Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

There represents a motor vehicle 2 according to the invention. The motor vehicle 2 is advantageously an electric vehicle in the sense that its drive is essentially provided by one or more rotating electrical machines.

The motor vehicle 2 comprises four wheels 4. Each wheel 4 forms a connection to the ground of the motor vehicle 2 and is capable of supporting it. The motor vehicle 2 comprises several braking systems including a first braking system 10. The first braking system 10 comprises braking devices 14. Each braking device 14 can be associated with one of the wheels 4. In a known manner, the braking devices 14 can be friction braking devices 14, with a disc and a brake pad whose brake lining rubs against the disc. Other mechanical braking devices are envisaged. Each braking device 14 can be actuated individually.

The motor vehicle 2 further comprises a braking control 16, such as a brake pedal. The braking control 16 may be a deceleration control. The braking control 16 is capable of acting on each braking device 14, for example via a centralized hydraulic circuit 12. In the present illustration, only two of the braking devices 14 are shown as being connected to the braking control 16, however each braking device 14 may be connected to the braking control 16 by the hydraulic circuit 12.

In order to reduce the effort that the user must exert on the braking control 16, the first braking system 10 comprises an actuation assistance device 18 for the braking control 16. The actuation assistance device 18 may be an electric actuator making it possible to increase the effort transmitted by the braking control 16, and increasing the pressure of the actuation fluid in the hydraulic circuit 12. Alternatively, the actuation assistance device 18 may be a pneumatic system amplifying a received effort.

The motor vehicle 2 comprises at least one rotating electric machine 20, preferably several rotating electric machines 20. According to one option of the invention, each wheel 4 is coupled to a rotating electric machine 20. This configuration makes it possible to improve the traction and road holding. According to one variant of the invention, each rotating electric machine is associated with one of the axles of the motor vehicle 2.

Each rotating electrical machine 20 is capable of operating as an electric motor when powered by a drive electric accumulator 22. In this configuration, the rotating electrical machine 20 is capable of driving the motor vehicle 2. The drive electric accumulator 22 may be an electric battery with several cells. The drive electric accumulator 22 may comprise supercapacitors.

Each rotating electrical machine 20 is also capable of operating as a generator. In this operating mode, the rotating electrical machine 20 is capable of recovering kinetic energy from the motor vehicle 2, and of converting it into electrical energy stored by the electric drive accumulator 22 in order to recharge it. The rotating electrical machines 20 form a second braking system when they operate as generators. According to an option of the invention, the motor vehicle 2 further comprises a third braking system such as a parking brake system (not shown). Other braking systems are envisaged.

In order to control the rotating electrical machines 20, the motor vehicle 2 comprises an accelerator control 24. The accelerator control 24 comprises a return position (shown in a solid line). The accelerator control 24 can be moved away from the return position by a user to a control position (shown in a dotted line). The return position can be a rest or equilibrium position. The accelerator control 24 can comprise return means to bring it back to the return position, and to oppose the user's effort. More generally, the return position is a first position.

The motor vehicle 2 further comprises means 26 for detecting a faulty mode of the first braking system 10. The faulty mode is detected when an anomaly is identified in the first braking system 10, for example in the hydraulic circuit 12. The detection means 26 may comprise means for controlling the actuation assistance device 18. The detection means 26 may comprise means for distinguishing a faulty mode from a normal mode of the first braking system 10. The normal mode is considered to be a nominal mode.

The detection means 26 comprise a pressure sensor and/or a current sensor measuring at least one piece of data from the actuation assistance device 18. The detection means 26 can compare a physical measurement with a theoretical instruction, in particular generated via the braking control 16. Thus, it is possible to detect an operating mode in which the user no longer receives physical assistance for braking.

According to one option of the invention, the detection means 26 further comprise means for comparing a measured deceleration with a set deceleration, preferably of each braking device 14.

The motor vehicle 2 further comprises a control unit 30. The control unit 30 is connected to the rotating electrical machines 20 in order to control them, for example by modulating their power supplies, in response to the position or movement of the accelerator control 24. The control unit 30 is connected to the detection means 26 in order to receive a signal relating to the faulty or normal mode of the first braking system 10. The control unit 30 is connected to the braking control 16 in order to apply a braking command.

The control unit 30 comprises a memory 32 and a computer 34. The control unit 30 may be a computer or a programmable electronic card. The memory 32 is capable of storing a computer program comprising code instructions, which when executed by the computer 34, make it possible to carry out a braking method according to the invention, and in particular as described below. The computer 34 may be a microprocessor.

The control unit 30 is configured so that in normal mode, when the accelerator control 24 is in the return position, the or at least one or each rotating electric machine 20 generates a first braking torque. faulty mode, and when the accelerator control 24 is in the return position, the control unit 30 is configured to control the or at least one or each rotating electrical machine 20 so that it generates a second braking torque greater than the first braking torque.

The control unit 30 is configured to control the or at least one or each rotating electrical machine 20 so as to generate the second torque provided that the detection means 26 detect, at least, a failure of said actuation assistance device 18. This feature makes it possible to respond to the case where only the muscular force of the user actuates the first braking system 10. In this case, the rotating electrical machines 20 provide additional braking by default. The level of braking assistance is increased by default. This improves the comfort of use of the vehicle as well as active safety. The vehicle brakes at a significant level before the user acts or reacts.

The control unit 30 is configured to control the or at least one or each rotating electrical machine 20 so that it generates the second braking torque when the braking control 16 is in the neutral position. Thus, without user intervention, the motor vehicle 2 benefits from an increase in braking torque when a failure of the first braking system 10 is detected.

The braking control 16 is able to be moved from the return position to a reference position; thus traveling a reference braking movement (DFR). When the braking control 16 is moved to the reference position, the control unit 30 is configured so as to control the or at least one or each rotating electrical machine 20 so that it generates a third braking torque. The third braking torque is greater than the second braking torque. This third braking torque value is reached in fault mode and in normal mode, and this for this same reference position. Thus, in the reference position the fault mode and the normal mode meet. The fault mode makes it possible to catch up with the braking level of the normal mode. This compensates for the reduction in braking capacity of the first braking system 10 and improves safety.

Depending on the effort exerted by the user, the accelerator control 24 travels through a predefined travel zone (ZDP). In the predefined travel zone, in normal mode, the control unit 30 is configured to control the or at least one or each rotating electrical machine 20 so that it generates an acceleration torque. The acceleration torque is a positive torque. It allows the motor vehicle 2 to accelerate on flat ground and uphill. In fault mode, the control unit 30 is configured to control the or at least one or each rotating electrical machine 20 so that it generates a braking torque. The braking torque is a resistive torque. The braking torque opposes the rotation of the corresponding rotating electrical machine 20. The braking torque allows the motor vehicle 2 to slow down on flat ground and downhill. In the predefined travel zone, the action of the or at least one or each rotating electrical machine 20 is reversed between the fault mode and the normal mode. This makes it possible to increase the functionality of the vehicle. In the fault mode, the braking control range is extended to reduce the efforts that the user must exert to achieve a given braking.

The control unit 30 is configured to control the or at least one or each rotating electrical machine 20 so that it generates an acceleration torque according to a mathematical function. The acceleration torque depends, at least, on a movement of the accelerator control 24, multiplied by a multiplier coefficient. In fault mode, the multiplier coefficient is a first coefficient, and in normal mode the multiplier coefficient is a second coefficient lower than the first coefficient. Therefore, the acceleration law increases less sharply in the fault mode. This contributes to reducing the speed of travel of the vehicle in fault mode.

The detection means 26 are configured to perform a comparison between a measured value and a corresponding setpoint value by a user braking instruction. The setpoint values are recorded in the memory 32. The comparison is performed by the computer 34.

In the case where the brake assist is a pneumatic system or an electronic actuator, during the braking phase, the detection means measure an oil pressure value in the hydraulic circuit 12 and compare this measured pressure value to a reference pressure value corresponding to the movement of the brake control imposed by the user. When the difference between the measured pressure value and the reference pressure value differ by at least one pressure threshold, the detection means 26 identify a fault mode. This pressure threshold may be greater than or equal to 20% of the reference pressure value.

According to a variant of the invention, the detection means 26 measure the deceleration of the vehicle, using speed measurements. This measured deceleration value is compared to a setpoint deceleration value. The setpoint deceleration value corresponds to a braking command. The setpoint deceleration value can be obtained as a function of correction coefficients linked to the temperature of the brake pads and the slope of the road. When the difference between the measured deceleration value and the setpoint deceleration value differs by a deceleration threshold, the detection means 26 identify a faulty mode. This deceleration threshold can be greater than or equal to 40% of the reference deceleration value.

These failure threshold choices optimize vehicle safety and functionality. They improve braking torque in the event of significant divergence, and maintain the nominal operating mode in other cases.

The first braking system 10, the detection means 26, the accelerator control 24, the or each rotating electrical machine 20, and the control unit 30, form a braking assembly according to the invention.

There illustrates the braking maps as a function of the mode of the first braking system of the motor vehicle according to the invention. These maps represent the braking and acceleration torques as a function of the positions of the brake and accelerator controls respectively. The return position and the neutral position are at point 0 of the abscissa axis.

The first line L1 represents the torque mapping on a wheel in normal mode. Line L2 represents the braking torque generated manually; without assistance and without action of the rotating electrical machine. Line L3 represents the torque mapping on the wheel in fault mode according to the invention.

There illustrates that at the reference braking displacement (DFR), at the reference position, the line L1 and the line L3 intersect. Therefore the maps in fault mode and in normal mode correspond and reach the third torque C3, for example the maximum braking torque of the vehicle. The invention makes it possible to compensate for the loss of braking in the fault mode.

The second braking torque C2 is configured to generate a deceleration of the vehicle varying from 2 m/s2 to 5 m/s2. The first braking torque C1 is configured to generate a deceleration of the vehicle varying from 0.1 m/s2 to 1 m/s2. The second braking torque C2 is greater than or equal to double or triple the first braking torque C1. This increases safety since by default the vehicle is braked more, independently of the driver.

The third braking torque C3 is configured to generate a deceleration of the vehicle varying from 5 m/s2 to 10 m/s2. The third braking torque C3 is greater than or equal to four times the first braking torque C1. The second torque C2 is between the first torque C1 and the third torque C3.

There also illustrates the reversal of behavior of the electric machine when the accelerator command moves within the predefined travel zone (PTZ). In normal mode, the accelerator command allows acceleration, while in fault mode the accelerator command imposes braking. Beyond the predefined travel zone (PTZ), both modes allow acceleration.

There represents a diagram of a motor vehicle braking method according to the invention. The motor vehicle corresponds to that described in relation to the . The mapping of the torque applied to one or more or to each wheel corresponds to those described in relation to the .

The braking process consists of the following steps:

Detection 100 of the accelerator control in the recall position.

Monitoring 102 of the first braking system so as to identify a faulty mode and the normal mode; or at least to distinguish the faulty mode from the non-faulty world.

Generation 104 of a first braking torque by the rotating electrical machine, when the first braking system is not in fault mode.

Generation 106 of a second braking torque, greater than the first braking torque, by the rotating electrical machine when the first braking system is in fault mode.

The braking method further comprises a step 108 of actuating the first braking system so as to generate a primary braking torque (PBT). The primary braking torque and the second braking torque are cumulative.

At the generation step 104 of the first braking torque and at the generation step 106 of the second braking torque, the rotating electrical machine recovers electrical energy. For a given speed of the motor vehicle, the rotating electrical machine recovers a first power during the generation step 102 of the first braking torque, and a second power during the generation step 106 of the second braking torque. The second power is greater than the first power, preferably at least twice as great.

Claims (10)

Motor vehicle braking assembly (2) comprising: a first braking system (10); an accelerator control (16) intended to be moved by a user from a return position; a rotating electrical machine (20) capable of driving the motor vehicle (2) as a function of a movement of the accelerator control (16); a control unit (30) of the rotating electrical machine (20) configured so that when the accelerator control (16) is in the return position the rotating electrical machine (20) generates a first braking torque (C1); characterized in that the braking assembly further comprises means (26) for detecting a fault mode of the first braking system (10), the control unit (30) being further configured so that in fault mode, when the accelerator control (16) is in the return position, said control unit (30) controls the rotating electrical machine (20) so that it generates a second braking torque (C2) greater than the first braking torque (C1). Braking assembly according to claim 1, characterized in that the first braking system (10) comprises a braking control (24) and an assistance device (18) for actuating the braking control (24), the control unit (30) is configured to control the rotating electrical machine (20) so that it generates the second braking torque (C2) when the detection means (26) detect a failure of said assistance device (18) for actuating. Braking assembly according to claim 2, characterized in that the braking control (24) is intended to be moved by the user from a neutral position, the control unit (30) is configured to control the rotating electrical machine (20) so that it generates the second braking torque (C2) when the braking control (24) is in the neutral position. Braking assembly according to one of claims 2 to 3, characterized in that the braking control (24) is capable of being moved from the return position to a reference position; when the braking control (24) is moved to the reference position, in fault mode and in normal mode of the first braking system (10), the control unit (30) is configured to control the rotating electrical machine (20) so that it generates a third braking torque (C3) greater than the second braking torque (C2). Braking assembly according to one of claims 1 to 4, characterized in that the means (26) for detecting a faulty mode of the first braking system are configured to perform a comparison between a measured braking value and a set braking value corresponding to a user braking instruction, the braking value being a brake fluid pressure or a deceleration. Braking assembly according to claim 5, characterized in that the control unit (30) is configured so as to detect the fault mode when the measured braking value is less than or equal to 80%, preferably 60%, of the braking value. Braking assembly according to one of claims 1 to 6, characterized in that the accelerator control (16) is capable of traveling through a predefined displacement zone in which, with the exception of the fault mode, the control unit (30) is configured so as to control the rotating electrical machine (20) so that it generates an acceleration torque; and in fault mode the control unit (30) is configured so as to control the rotating electrical machine (20) so that it generates a braking torque when the accelerator control (16) is in said predefined displacement zone. Motor vehicle (2) comprising a braking assembly, characterized in that the braking assembly conforms to one of claims 1 to 7, and in that the motor vehicle (2) comprises an electric drive accumulator (22), the rotating electric machine (20) is capable of recharging the electric drive accumulator (22). Method for braking a motor vehicle (2) comprising a braking assembly, characterized in that the braking assembly conforms to one of claims 1 to 7; the method comprising the following steps:

1. detection (100) of the accelerator control in the return position;
2. monitoring (102) of the first braking system (10) so as to identify a faulty mode and the normal mode;
3. generation (104) of a first braking torque (C1) by the rotating electrical machine (20), when the first braking system (10) is not in fault mode;
4. generation (106) of a second braking torque (C2), greater than the first braking torque (C1), by the rotating electrical machine (20) when the first braking system is in fault mode.

Method according to claim 9, characterized in that it further comprises a step of actuating (108) the first braking system (10) so as to generate a primary braking torque; said primary braking torque being added to the second braking torque (C2).