Method for capping a torque transmitted to a differential mechanism by a motor member
Patent Information
- Application Number
- PCT/EP2026/055232
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-26
- Filing Date
- 2026-02-26
- Publication Date
- 2026-09-03
Smart Images
Figure EP2026055232_03092026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE OF THE INVENTION: Method for limiting the torque transmitted to a differential mechanism by a driving element
[0003]
[0001] The present invention relates to a method for limiting the torque transmitted to a differential mechanism by a drive component, particularly in a motor vehicle. With regard to the drive component in question, particular attention is paid to the case of an electric traction machine, although the invention can also be applied to an internal combustion engine.
[0004] Electric traction machines exhibit very high torque at zero rotational speed. A particularly critical case is a so-called "full throttle takeoff," that is, starting the vehicle from zero speed with the driver wanting to achieve the greatest possible acceleration.
[0005] Torque transmission through the ground typically occurs via a drive axle, either the front or rear axle. The case of four-wheel drive vehicles is also considered for the purposes of this invention.
[0006] If the traction of the drive train is not uniform between the left and right wheels, the wheel with less traction will begin to rotate faster than the wheel with more traction. This is where the differential mechanism comes into play, causing slippage. 'Differential slippage' refers to a difference in rotational speed between the left and right wheels of the same axle.
[0007] Anti-slip systems are known to address the situation described above by applying braking force to the wheel with less traction, forcing it to slow down and simultaneously increasing the torque transferred to the ground by the other wheel. This anti-slip action is usually controlled by a computer responsible for the vehicle's braking function. In practice, however, a correction by the anti-slip system takes some time, at least several tens of milliseconds, and possibly even a few hundred milliseconds.
[0008] Before the anti-slip correction intervenes, a very significant slip can occur, which puts stress on the differential mechanism, particularly the satellites and planetary gears, and the elements that contribute to their rotational assembly and their pressure retention.
[0009] The amplitude of the slip is favored by the very strong dynamics of the electric traction machine.
[0010] Faced with this situation, some manufacturers have opted to oversize the differential mechanism in terms of slip resistance and torque characteristics; however, this has an adverse impact on the cost and / or size of the differential mechanism.
[0011] [0 The inventors sought to improve the situation, without oversizing the differential mechanism, and without reducing the expected performance of the full-power takeoff configuration on adhesive ground.
[0012]
[0010] To this end, a method is proposed for capping a torque transmitted to a differential mechanism of a motorized vehicle axle by a drive unit, the vehicle axle comprising a left wheel and a right wheel, each wheel being equipped with a rotation speed sensor,
[0013] the process being characterized in that it comprises:
[0014] a) determine on the one hand a maximum torque value at zero slip, (designated by 'CMaxPic'), and on the other hand a general limit torque value for a range of predetermined slips (designated by 'CMaxMoy'), b) define a first maximum torque curve corresponding to a reference critical traction case;
[0015] c) establish an overall ceiling curve setting a maximum torque value as a function of differential slip.
[0016] d) acquire instantaneous differential slip,
[0017] e) determine, from the overall protection curve, the maximum torque value to be respected,
[0018] f) if the required torque is greater than the maximum torque value to be respected, reduce it to the maximum torque value to be respected, characterized in that the overall capping curve includes:
[0019] - a first portion formed by a bearing at the maximum torque value with zero slip, CMaxPic, extending from zero slip to a first slip value,
[0020] - a second portion formed by a continuous and decreasing curve, extending from the first slip value to a second slip value,
[0021] - a third portion formed by a bearing at the general limit torque value, CMaxMoy, extending from the second slip value to a third slip value,
[0022] - a fourth portion coinciding with the first maximum torque curve extending beyond the third slip value.
[0023]
[0011] We are referring here in particular to the case where the driving element is an electric traction machine, without excluding the case where the driving element is an internal combustion engine.
[0024] Thanks to the provisions promoted above, a surge in rotational speed is avoided on the side of the wheel with the least grip.
[0025] Indeed, thanks to the advantageous process proposed here, the reaction time of the torque reduction on the side of the electric machine controller is much lower than the reaction time required for the traction control system managed by the braking computer to perform a braking action and request a reduction of torque from the motor component.
[0026] For the sake of brevity in the following, we will use CMaxPic to denote the maximum torque value at zero slip, and we will use CMaxMoy to denote the general limit torque value for a predetermined range of slips.
[0027]
[0015] The torque curves of interest in this document express limiting torque values as a function of the slip prevailing in the differential mechanism. In other words, the x-axis shows slip values (GL) expressed in revolutions per minute and the y-axis shows torque values (Cpd-Diff) that apply to the input wheel of the differential.
[0028]
[0016] It should be noted that the overall capping curve is based on the two values CMaxPic, CMaxMoy and the first maximum torque curve; this curve will be described in more detail later. The overall capping curve is simple to construct. It effectively protects the differential mechanism from a rapid increase in slippage during a sudden increase in the torque demanded of the electric machine.
[0029]
[0017] It is noted that the overall ceiling curve is continuous and generally decreasing, according to the example decreasing by part with two levels.
[0030] However, despite the presence of the strategy described above, the vehicle's dynamics on a grippy surface are not impacted at all; the torque ceiling does not come into play for a full-throttle takeoff situation on a surface with good grip, and even generally on a surface without significant left-right grip imbalance, for which there is no sudden slippage in the differential mechanism.
[0031] Note that CMaxPic represents the stress resistance of the gear teeth, particularly their mutual contacts, and of the differential housing bearings. The highest stresses occur when the ground is grippy, the wheels are not slipping, and consequently, slippage remains very low, limited by the steering kinematics when cornering.
[0032]
[0020] It is noted that CMaxMoy represents the maximum torque over a long time and a range of predefined slip values, and it characterizes the holding of the assembly of the satellite bearings, in particular under slip.
[0033]
[0021] CMaxPic and CMaxMoy depend on the technological choices made for the construction of the differential mechanism, in particular the mounting of the satellite and planetary gears.
[0034] It should be noted that the reduction of torque is a short-term action which is then relayed later by the anti-slip regulation process in which the braking system is in operation.
[0035] The instantaneous slip corresponds to the value |CÜL-CÜR|, where CÜL is the instantaneous rotational speed of the left wheel and UJR is the instantaneous rotational speed of the left wheel, and we take the absolute value of the difference since it is either one wheel or the other that undergoes a slip.
[0036] In practice, the rotational speed information for each wheel is captured by a control unit responsible for the braking system and transmitted to the control unit managing the engine via very fast message processing. The term 'acquiring instantaneous slip' encompasses several possible solutions; the difference can be determined by the braking control unit and transmitted without delay to the control unit managing the engine, or the difference can be determined by the control unit managing the engine. It is also possible to have dual-output wheel speed sensors, so that the control unit managing the engine can directly read the individual wheel speeds without using a message transmission system.
[0037] The overall capping curve can be established beyond the third slip value up to a high slip value, but in practice this value is capped by the maximum possible speed protections on the drive unit, both for an electric traction machine and for an internal combustion engine.
[0038] According to one realization, the second portion is a connecting curve between the values CMaxPic and CMaxMoy, with a continuous first derivative without jump, of value, and a negative then positive second derivative.
[0039]
[0027] Expressed in other words, the connecting curve allows the bearing at height CMaxPic and the bearing at height CMaxMoy to be connected without an inflection point.
[0040] According to one design, the second portion is a sigmoid curve. This allows for a smooth transition between the first and second stages, which is conducive to seamless regulation of the correction loop.
[0041] Preferably, the selected sigmoid curve is symmetric with respect to the midpoint between the first slip value and the second slip value, i.e., a symmetry with respect to a locus point of abscissa (BP1+BP2) / 2, BP1 being the first slip value and BP2 being the second slip value.
[0042] According to one implementation, the sigmoid curve is not calculated in real time, it is calculated in "offline" mode and transcribed into a calibration table.
[0043]
[0031] According to one embodiment, the first maximum torque curve corresponds to a case of loading with the foot to the floor in a condition with a differential of adhesion between the left and right wheels of at least 0.5.
[0044] The term 'full throttle loading' refers to a demand for torque at maximum depress of the vehicle's accelerator pedal.
[0045] In practice, we can choose a case of critical traction in a straight line where there is correct grip (grip 1) for one drive wheel and very low grip (of type 0.2) for the other wheel.
[0046] It is noted that the first reference curve can notably take into account the weight of the vehicle, or even its load, without necessarily taking into account the geometric details of the rolling platform.
[0047] The first reference curve is not calculated in real time, it is calculated in "offline" mode and transcribed into a calibration table.
[0048]
[0036] According to one embodiment, the first slip value is determined from a full steering kinematic following a vehicle type of interest.
[0049]
[0037] In other words, this corresponds to a minimum turning radius configuration. Formulas known to those skilled in the art are used, whether for the front or rear axle, to determine the difference in rotational speed between the outer and inner wheels when the vehicle's steering is fully turned and the vehicle is maneuvering.
[0050] As a reminder, the steering angle of a vehicle refers to the angle defining the orientation of the vehicle's drive wheels relative to a longitudinal vertical plane of the vehicle (wheels on the ground on a horizontal plane). The full steering angle refers to the maximum value that the steering angle can take, this maximum value being a function of the model, or type of vehicle corresponding to the vehicle of interest (the vehicle of interest being the vehicle on which step d) of acquiring instantaneous differential slip is performed). A full steering angle kinematic refers to the transition from a zero steering angle to the full steering angle.
[0051] According to one implementation, the first slip value is stored in a calibration memory.
[0052]
[0040] It is therefore possible to use a single strategy with a parameterization dependent on the rolling platform and the type of vehicle.
[0053]
[0041] As a reminder, a calibration memory here refers to a memory of a processor, intended to store at least calibration data obtained during a prior calibration step of a type of vehicle corresponding to the vehicle of interest.
[0054] In one implementation, the second slip value is separated from the first slip value by at most 50 RPM (revolutions per minute). Expressed in other words, BP2-BP1 < 50, most often close to 30 to ensure a rapid transition between the first and second plateaus of the overall capping curve.
[0055] According to one embodiment, the third slip value is defined as an abscissa corresponding to an intersection between the first maximum torque curve and the bearing at the general limit torque value.
[0056] We note that the third slip value can be in the range of 100 to 200 RPM. In a typical example, the third slip value is found around 150 RPM.
[0057] According to one embodiment, steps d) to f) are carried out periodically with a high recurrence of at least 100 times per second.
[0058] The process thus exhibits very high responsiveness and torque correction is extremely fast.
[0059] For example, the transmission of instantaneous slip is done by the braking computer to the engine computer on a fast priority frame.
[0060] The invention also relates to a system comprising a motor component associated with a motor component control unit, a braking system (5) comprising a braking system control unit (4), the motor component control unit being configured to implement steps d) to f) of the method as described above. The invention also relates to a motor vehicle, comprising at least one electronic control unit in which steps d) to f) of the method as described above are implemented.
[0061] The electronic control unit can be the engine control unit or another on-board computer.
[0062] As a typical example, the motor vehicle is an electrically powered vehicle.
[0063] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which:
[0064] [Fig. 1] schematically illustrates a diagram of a vehicle in top view J
[0065] [Fig.2] illustrates a functional diagram of a vehicle axle in top view;
[0066] [Fig.3] shows a torque ceiling curve passing through the differential mechanism, as a function of the slip prevailing in the differential mechanism;
[0067] [Fig.4] shows a timing diagram that illustrates an intervention situation of the proposed strategy to reduce the wheel rotation surge in the configuration of a full-throttle takeoff.
[0068] In the various figures, the same references designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.
[0069] [0 With reference to Figure 1, a VHL vehicle generally has a front axle and a rear axle. The front axle is also called the front axle; it is usually the steering axle. The rear axle is also called the rear axle.
[0070] Each of the two axles can be motorized. When only the front axle is motorized, it is called a front-wheel drive vehicle, and when only the rear axle is motorized, it is called a rear-wheel drive vehicle.
[0071]
[0056] In the figures, the vehicle and its axle of interest are located with respect to an orthogonal frame of reference as follows: the vertical direction is noted Z, the horizontal direction called longitudinal is noted X, the horizontal direction called transverse is noted Y.
[0072]
[0057] Of course, as illustrated in Figure 1, the two axles can be powered simultaneously. The front axle includes a drive unit GMP1 with a first differential mechanism 7. The front axle includes a drive unit GMP2 with another differential mechanism 7 of a similar nature to the first.
[0073] System
[0074] We turn to Figure 2, which illustrates a driven axle of the vehicle, front or rear, with general axis Y0. The left wheel WG is driven by a first wheel shaft 21. The right wheel WD is driven by a second wheel shaft 22. The first wheel shaft 21 and the second wheel shaft 22 are respectively rotationally fixed to the output pinions of the differential mechanism 7.
[0075]
[0060] The MOT drive unit is here an electric traction / propulsion machine, although the invention can also be applied to the case of an internal combustion engine drive unit, and of course to the case of hybrid powertrains. The MOT drive unit is usually associated with a gearbox, thus forming a geared motor.
[0076] According to the illustrated example, the output of the geared motor includes an output pinion 60 with axis Y1 permanently meshed with the input wheel 70 of the differential mechanism 7.
[0077] The input wheel 70 of the differential 7 is rigidly connected to a differential housing 77, which carries bevel gears 73, 74 in a known arrangement, with rotational mounting. Output bevel gears 71, 72 mesh with the planet gears 73, 74 in a known arrangement. Each output bevel gear 71, 72 drives a wheel shaft 21, 22.
[0078] In a straight line and with no wheel slippage, the satellite gears 73 and 74 do not rotate. However, when one wheel rotates faster than the other, for example, when cornering, the satellite gears 73 and 74 rotate, putting stress on their rotating assembly. Furthermore, if one of the wheels (WG, WD) is locked, the other wheel rotates twice as fast as the differential input wheel.
[0079] When one wheel is on a very slippery surface, the same speed difference can be observed, as virtually no traction torque is transmitted to the wheel on the grippy surface. It should also be noted that it is when both wheels are on a grippy surface that very high torque can be transmitted through the differential mechanism, for example, during a full-throttle maneuver performed by the driver on dry asphalt.
[0080]
[0065] The differential mechanism is designed to transmit a certain torque, particularly in applications requiring good road grip. The structure and configuration of the differential mechanism 7 lead to the definition of maximum torque limits that the differential mechanism can withstand, both at peak and over a longer period, without causing damage. These limit values will be discussed later.
[0081] A rotational speed sensor 31, a brake disc 81, and a braking component 41, for example a caliper with a hydraulic piston and friction pads, are planned in relation to the left wheel WG. Similarly, a rotational speed sensor 32, a brake disc 82, and a braking component 42 are planned in relation to the right wheel WD.
[0082] As is known in itself and therefore not detailed here, the braking system comprises a braking system control unit 4 and a hydraulic unit 5 connected by hoses to the braking components. Hybrid electro-hydraulic braking systems, which may exhibit shorter but still longer response times than the early short-loop torque reduction proposed by the present invention, can also be considered here.
[0083] We note that the wheel speed sensors are connected to the braking computer 4 (lines represented by dotted lines in figure 2).
[0084] The MOT engine component is controlled by an engine control computer 1, ECM via a power electronics 2, of the inverter type.
[0085]
[0070] The brake control unit 4 and the engine control unit 1 communicate with each other via a high-speed data bus 14.
[0071] It should be noted that the wheel speed sensors could have dual outputs to deliver information directly to the engine control unit. According to yet another embodiment, the wheel speed sensors could be duplicated, e.g., one for the braking system and one for the engine control system (direct acquisition).
[0086] Strategy and process
[0087]
[0088] The discussion will focus on the use of two torque limit values and an iso-power curve corresponding to a use case that will be discussed later. Regarding slight slippage, this refers to the natural difference in rotational speed that prevails when the vehicle travels a curve with a certain steering angle (excluding wheel slippage).
[0089] First, we determine a maximum torque value at zero or low slip called CMaxPic.
[0090] We note that CMaxPic represents the stress resistance of the teeth, in particular their mutual contacts, and of the bearings of the differential body.
[0091] Furthermore, CMaxMoy represents the maximum torque over a long time and a range of predefined slip values, and it characterizes, among other things, the strength of the assembly of the satellite bearings.
[0092]
[0077] CMaxPic and CMaxMoy depend on the technological choices made for the construction of the differential mechanism, including the dimensions, materials, surface treatments, and the mounting of the satellite and planetary gears.
[0093] The CMaxPic and CMaxMoy values are derived from characterization tests on a sample of differential mechanisms. In practice, we have CMaxMoy < CMaxPic. Mechanical solutions for the differential mechanism
[0094] The method uses, in addition to the CMaxPic and CMaxMoy values, a first maximum torque curve CRF corresponding to a reference critical traction case. CMaxMoy can be between 0.6 x CMaxPic and 0.9 x CMaxPic.
[0095]
[0080] The first maximum torque curve CRF corresponds to a case of loading with the foot to the floor in a condition with a differential of adhesion between the left and right wheels of at least equal to 0.5.
[0096] The first maximum torque curve CRF is an isopower curve, which is close to a hyperbolic shape in the torque-as-slip diagram (see figure 2).
[0097] In practice, we can choose a case of critical traction in a straight line where there is correct grip (grip 1) for one drive wheel and very low grip (of type 0.2) for the other wheel.
[0098] The process involves establishing an overall CGP capping curve based on the aforementioned data.
[0099] More specifically, the overall CGP ceiling curve is constructed as follows with 4 portions as seen in Figure 2.
[0100] A first portion P1 is formed by a plateau at the maximum torque value CMaxPic, from zero slip to a first slip value BP1.
[0086] A third portion P3 is formed by a plateau at the general limit torque value (CMaxMoy), from a second slip value BP2 to a third slip value BP3.
[0101] A second portion P2 is formed by a decreasing curve, from the first slip value to a second slip value
[0102] More precisely, the second portion P2 appears as a connecting curve between the maximum torque value (CMaxPic) and the general limiting torque value (CMaxMoy), with a continuous derivative without a jump.
[0103] The transition curve has a negative second derivative followed by a positive one.
[0104] A fourth portion P4 coinciding with the first maximum torque curve CRF from the third slip value BP3.
[0105] Salon, for example among other possibilities, the second portion P2 is a sigmoid curve.
[0106] The sigmoid curve can be written as follows:
[0107]
[0108] In this formula, A is a gain factor, A is 1 for a symmetric solution, but A could be different from 1.
[0109] The process involves the recurrence of the following steps d), e) and f).
[0110] Step d) consists of acquiring, directly or indirectly, the instantaneous slip GL, which is placed on the x-axis (position 53 according to the example in figure 3);
[0111] Step e) consists of determining, from the overall protection curve, the maximum torque value to be respected (position 55, from point 54 on the CGP curve).
[0112] Step f) provides: if the required torque is greater than the maximum torque value to be respected, reduce it to the maximum torque value to be respected. The second slip value BP2 is separated from the first slip value BP1 by at most 30 RPM (revolutions per minute).
[0113] The first slip value BP1 and the second slip value BP2 are stored in a calibration memory.
[0114] The third slip value BP3 is defined as an abscissa corresponding to an intersection 15 between the first maximum torque curve CRF a bearing at the general limit torque value CMaxMoy.
[0115] It should be noted that a smoothing correction of the curve can be planned around intersection 15 to avoid the presence of an inflection point at that location, yeah.
[0116] The third slip value BP3 is generally between 100 rpm and 200 rpm, well beyond the value BP1 which corresponds to maximum steering, or full steering; it is from this slip value that the anti-slip system by the braking system intervenes.
[0117] According to one example, the third slip value BP3 can be found in the vicinity of 150 rpm.
[0105] It should be noted that the evolution of the slip and the torque can lead to the activation of the torque reduction at any point on the overall protection curve CGP, and in particular, for example, in the transition curve P2 between the first stage (portion P1) and the second stage (portion P3). It is noted that the smooth transition between the first and second stages via the second portion P2 makes it possible to avoid possible jolts in certain torque regulation configurations initiated by the electric machine.
[0118]
[0106] The timing diagram in Figure 4 shows a case of full-throttle loading in a condition with a differential of adhesion between the left and right wheels of at least 0.5. For example, one wheel is on a sheet of ice.
[0119] Figure 4 shows on one hand the evolution of the torque Cpl transmitted to the differential by the electric machine and on the other hand the slip GLœ observed at the wheel speeds and therefore which prevails at the level of the differential mechanism.
[0120] [1 The parts of the curves in dotted lines illustrate the scenario as it would take place without the present invention, while the parts of the curve in solid lines illustrate the scenario with the application of the method proposed by the present invention.
[0121] [1 The initial portion 91 of the torque curve is common to both scenarios. At time t1, according to the proposed method, the slip and the applied torque reach the overall protection curve (point GL1, Fig. 4), (this could be, for example, point 54 in Figure 3). A torque reduction action is immediately initiated. A very pronounced inflection point is observed, with a rapid decrease 97 in the delivered torque. This correction corresponds to the arrow F1 in Figure 3, which illustrates the direction of this correction; the action returns below the curve.]
[0122] Returning to Figure 4, the initial portion 90 of the GLœ sliding curve is common to both scenarios.
[0123] At time t1, in the scenario without the present invention (dotted line 95), the slippage increases significantly until time t2, when the braking action initiated by the brake control unit begins to take effect. Conversely, thanks to the invention and the torque reduction initiated at time t1, the slippage increases slightly due to the inertia of the components involved (particularly the wheels) and then decreases (section 94). It is noted that between times t1 and t2, the torque applied to the wheels has been significantly reduced by the short loop of the electric machine's control strategy, even before the brake control unit can act on the slipping wheel.
[0124] Advantageously, a surge in slip 98 is avoided which, due to its large amplitude, can present a risk of damage to the differential bearings.
[0125] The period between times t2 and t3 is when the application of braking force 96 on the slipping wheel allows for a drastic reduction in slippage combined with the torque reduction action delivered by the machine.
[0114] Beyond time t3, the regulation controlled by the braking computer takes over and regulates traction, tolerating a certain residual slippage (εGL-ReguI) to transmit optimal torque (Cpl-Regul) to the ground. This regulation phase generally corresponds to zone 16 in Figure 3.
[0126] It should be noted that Figure 4 represents only a simplified example for the concise exposition of the invention.
[0127] In practice, the early regulation loop implemented in the control of the electric machine is a high recurrence loop, e.g. at least 100 hertz; typically there is at least one calculation and correction step every 10 ms, or even more.
[0128]
[0117] A person skilled in the art understands that, although a differential with a spherical configuration has been described, the invention is also applicable to any other configuration and / or construction of a differential mechanism.
Claims
DEMANDS 1. A method for limiting the torque transmitted to a differential mechanism (7) of a motorized vehicle axle by a drive unit (MOT), the vehicle axle comprising a left wheel (WL) and a right wheel (WR), each wheel being equipped with a rotational speed sensor (31, 32), the method being characterized in that it comprises: a) determine on the one hand a maximum torque value at zero slip (CMaxPic), and on the other hand a general limit torque value (CMaxMoy) for a predetermined range of slips, b) define a first maximum torque curve (CRF) corresponding to a reference critical motority case; c) establish a global ceiling curve (GCC), establishing a maximum torque value based on differential slip, d) acquire an instantaneous slip (GL) of the differential, e) determine, from the overall capping curve, the maximum torque value to be respected, f) if the required torque is greater than the maximum torque value to be respected, reduce it to the maximum torque value to be respected. characterized in that the overall capping curve (CGP) comprises: - a first portion (P1) formed by a plateau at the maximum torque value with zero slip (CMaxPic), extending from zero slip to a first slip value (BP1), - a second portion (P2) formed by a continuous and decreasing curve, extending from the first slip value to a second slip value (BP2), - a third portion (P3) formed by a bearing at the general limit torque value (CMaxMoy), extending from the second slip value to a third slip value (BP3), - a fourth portion (P4) coinciding with the first maximum torque curve (CRF) extending beyond the third slip value (BP3).
2. Method according to claim 1, wherein the second portion (P2) is a transition curve (P2) between the maximum zero-slip torque value (CMaxPic) and the general limit torque value (CMaxMoy), with a continuous first derivative without value jump, and a negative then positive second derivative.
3. Method according to claim 2, wherein the second portion (P2) is a sigmoid curve.
4. A method according to any one of claims 1 to 3, wherein the first maximum torque curve (CRF) corresponds to a full-throttle loading case with a differential of adhesion between the left and right wheels of at least 0.
5.
5. Method according to any one of claims 1 to 4, wherein the first slip value (BP1) is determined from a full steering kinematics following a vehicle type of interest.
6. Method according to claim 2, wherein the first slip value (BP1) is stored in a calibration memory.
7. Method according to any one of claims 1 to 6, wherein the third slip value (BP3) is defined as an abscissa corresponding to an intersection (15) between the first maximum torque curve (CRF) and the bearing at the general limit torque value (CMaxMoy).
8. A method according to any one of claims 1 to 7, wherein steps d) to f) are carried out periodically with a high recurrence of at least 100 times per second.
9. System comprising a motor component (MOT) associated with a motor component control computer (ECM), a braking system (5) comprising a braking system control computer (4), the motor component control computer being configured to implement steps d) to f) of the method according to any one of claims 1 to 8.
10. Motor vehicle, comprising at least one electronic control unit in which steps d) to f) of the method according to any one of claims 1 to 8 are implemented.