FR3091247A1 - Method and system for managing a setback torque setpoint applied to the drive wheels of a motor vehicle with electric or hybrid traction - Google Patents

Abstract

This method of managing an anti-recoil torque setpoint applied to the powerplants of a motor vehicle with electric or hybrid traction, comprises the following steps: - the speed of the vehicle is determined; - the position of the lever is identified transmission control and, as soon as a change in position of the lever is detected, - a sign is applied to the vehicle speed as a function of the final position of the control lever; - a temporal filtering of the speed is carried out; and - the anti-reverse torque setpoint is produced from the filtered speed value. Figure for the abstract: Fig 6

Description

Description

Title of the invention: Method and system for managing a setback torque setpoint applied to the drive wheels of a motor vehicle with electric or hybrid traction

The present invention relates to a method and a system for managing a setback torque setpoint applied to the drive wheels of a motor vehicle with electric or hybrid traction.

The present invention relates more particularly to the implementation of an anti-reverse function when the vehicle is traveling in the opposite direction to that which corresponds to the position of a transmission control lever.

It may, for example, be a vehicle traveling in reverse while the control lever is in the "Drive" position, or forward, or a vehicle traveling in forward, then the control lever is in the "Reverse" position, or reverse.

In this case, the anti-roll back function ensures a deceleration of the vehicle allowing the vehicle to be brought back in the correct direction of travel.

The anti-rollback function on a hybrid or electric vehicle must be managed taking into account the other functionalities offered by the vehicle's powertrain system. This is in particular the "ramping" function which allows the vehicle to travel at low speed when the control lever is in the "Drive" position, that is to say in the same speed ranges as the anti-recoil, but with torque setpoints having significantly lower amplitudes, with ratios ranging from 1 to 5.

This problem also arises with electric or hybrid vehicles which offer a mode known by the English term of "One Pedal", in which acceleration and braking are controlled by a single pedal, and for which the regenerative braking level is much higher than with a conventional driving mode.

Other vehicles also offer "Brake" or braking driving modes which have a high level of regenerative braking, identical or similar to that offered by the single pedal mode, but without ramping mode.

This absence of ramping mode generates a zero force setpoint at zero speed, incoherent with a need for anti-reverse as soon as the speed becomes negative.

We will first refer to Figure 1, which illustrates the evolution of the ramp torque settings as a function of the speed, on the one hand when the lever is in the "Drive" position (curve I) and on the other hand, when the lever is in the "Brake" position (curve

Π).

With regard to the anti-rollback or "rollback" force, this has the objective of bringing the vehicle back in the correct direction of travel when it moves in the opposite direction to that of the lever position.

To do this, the vehicle's electrical machine recovers the kinetic energy from the vehicle to the wheel and converts it into electrical energy, via the inverter of the machine, to store it in the battery.

Referring to Figure 2 which illustrates the evolution of the anti-kickback force as a function of the vehicle speed, when the control lever is in the "Drive" position, if the vehicle descends a slope, a anti-recoil force which varies according to curve III is applied to the wheel in order to brake the vehicle. Similarly, if the lever is in the "Brake" position (curve IV), a force is applied to the wheel in order to brake the vehicle.

The anti-recoil instructions are however limited by the maximum recovery potential that the electrotechnical system constituted by the electric machine, the inverter and the battery can recover. We therefore observe a gradual decrease in the anti-rollback potential of the vehicle from a certain speed (curve V).

However, it should be noted that these operating modes are accompanied by sudden variations in speed change due to changes in torque setpoint applied or according to the selected operating modes, for example during a transition between a mode of rampage operation and anti-reverse mode.

Referring to Figure 3 in which the curve VI corresponds to the change in the force applied to the wheel as a function of the speed during ramping, when the control lever is in the "Reverse" position and the curve VII corresponds to the anti-kickback force when the control lever is in the "Drive" position.

At very low speeds, the powertrain management system allows rapid variations in the position of the lever from "Reverse" to "Drive" and from "Drive" to "Reverse". It also authorizes “Reverse” to “Brake” and “Brake” to “Reverse” maneuvers. These maneuvers are commonly referred to by the English term “Rock-Cycling” and are commonly performed during the garage of a vehicle.

During operation of this type, as shown in Figure 3, the transition from one position of the control lever to another is accompanied by a significant variation in the force applied to the wheel.

For example, during a creep with the control lever in reverse, from zero speed, the force applied to the wheel changes according to curve VI. If, for example, the driver decides at 3 km / h to change the position of the lever to move it from the "Neutral" position to the "Drive" position, the force difference applied to the wheel is approximately 5500 Newton , which corresponds to a felt shock of around 3 m / s ³ .

The object of the invention is therefore to overcome these various drawbacks and to propose a method and a system for managing a setpoint of anti-recoil torque making it possible to avoid the appearance of shocks perceived negatively by the driver and passengers.

The invention therefore relates to a method of managing a setback torque setpoint applied to the drive wheels of a motor vehicle with electric or hybrid traction, according to which:

- determining the speed of the vehicle;

The position of a transmission control lever is identified and, as soon as a change in position of the lever is detected,

- a sign is applied to the speed of the vehicle as a function of the final position of the control lever,

- a temporal filtering of the speed is carried out, and

- we develop the setpoint of anti-reverse torque from the filtered speed value.

In one embodiment, the torque setpoint is developed from maps in which torque values are stored as a function of the speed of the vehicle, for different positions of the control lever.

According to another characteristic, during filtering, the speed value is canceled, then filtered, the filtered value converging towards a real speed value.

For example, the speed is measured from the engine speed.

It can be measured from the gear ratio of the differential and the radius of the drive wheels.

According to another characteristic, a vehicle anti-reverse function is activated if the vehicle is traveling in the opposite direction to that which corresponds to the position of the control lever, the anti-reverse torque setpoint being reduced until the vehicle drives in the direction corresponding to that of the lever.

Another subject of the invention, according to another aspect, is a system for managing a setback torque setpoint applied to the drive wheels of a motor vehicle with electric or hybrid traction.

This system includes means for calculating the speed of the vehicle, means for identifying the position of a transmission control lever and detecting a change in position of said lever, calculation means for applying a sign to the speed of the vehicle as a function of the final position of the control lever and for temporally filtering the speed, the anti-reverse torque setpoint being produced from the filtered speed value.

According to another characteristic, the system includes maps in which torque values are stored as a function of the speed of the vehicle, for different positions of the control lever.

Other objects, characteristics and advantages of the invention will appear on reading the following description, given solely by way of nonlimiting example, and made with reference to the appended drawings in which:

[Fig.l]

[Fig.2] respectively illustrate the evolution of the rampage setpoints and the anti-rollback forces as a function of the speed of the vehicle;

[Fig.3] illustrates the problem of the transition between a rampage mode and an anti-recoil mode;

[Fig.4] is a block diagram of a setback management system according to the invention;

[Fig.5] illustrates the calculation means for calculating the speed of the vehicle;

[Fig.6] illustrates the main phases of a method for managing a setback torque setpoint according to the invention,

[Fig.7] shows curves showing the evolution of the vehicle speed, the reconditioned vehicle speed, the position of the control lever and the final setback.

We will first refer to Figures 4 and 5 which respectively illustrate a block diagram of a system for managing a setback torque setpoint for a motor vehicle and a stage for modeling the speed of the vehicle used by the system in Figure 4.

More specifically, the system illustrated in Figure 4 is intended to develop an anti-recoil force applied to the drive wheels of a motor vehicle with electric or hybrid traction, especially when the position of a control lever transmission is modified from "Drive", "Brake" and "Reverse" positions.

The system visible in Figure 4 comprises a first stage 1 which identifies the position of the transmission control lever from a signal L delivered by the lever.

For example, when the lever is in the "Neutral" position, the output of this stage 1 is at zero.

When the lever is in position between "Drive" or "Brake" and the vehicle is reversing, the output is at 1.

When the lever is in the "Reverse" position and the vehicle is advancing, the output is at

2.

The system also comprises a second stage 2 which receives as input the measured speed V of the vehicle and formats the speed of the vehicle as soon as a change in position of the lever is detected.

This stage 2 applies a sign to the speed of the vehicle as a function of the final position, after changing the position of the control lever.

When the electric motor is in the "Drive" position, the speed is between 0 and V. When the motor is in the position between "Reverse", the speed is between zero and -V.

The first and second stages are connected to a shaping stage 3 which ensures a ramp variation in the speed values delivered by the second stage, as a function of the command delivered by the first stage. In other words, it is to impose slow variations in the speed values from the second stage.

The system also includes a filtering stage 4 which provides dynamic temporal filtering of the speed preventing the abrupt transitions detailed previously reference to FIG. 3.

The filtered speed is delivered to a stage 5 which ensures the actual development of the anti-reverse setpoint. This stage uses the filtered speed to generate the final anti-reverse setpoint, regardless of the position of the lever.

This stage 5 is based on the use of maps 6 and 7 in which are stored anti-reverse force values as a function of the speed of the vehicle, for each position of the control lever.

As illustrated, the stage 5 comprises a first map 6 in which are stored values of torque to the wheel as a function of the speed, when the lever is in the "Drive" position and a second map 7 in which Torque values are stored at the wheel as a function of the speed when the lever is in the position between "Brake".

The values delivered by the maps 6 and 7 are delivered to a shaping module 8, which prevents sudden transitions. This module is controlled from the position of the lever.

The output of this module 8 delivers the anti-recoil setpoint used by the electrotechnical propulsion system.

Referring to Figure 5, the speed V used by the module 2 is modeled from the speed of rotation of the motor ω. This speed is divided by the reduction ratio R of the differential then is converted into radians per second by multiplying by 2χπ / 60.

The converted value is then multiplied by the radius of the drive wheels R ’and then is multiplied by a coefficient equal to 3.6 to deliver, at the output, a vehicle speed modeled in kilometers / hour.

The speed of the vehicle thus reconstituted is continuous around 0 thanks to the taking into account of the zero rotation value of the electric machine.

Referring to Figure 6, the system which has just been described operates as follows.

In a first step 10, the speed of the vehicle is determined using the calculation module illustrated in FIG. 5.

The value thus determined is supplied to stage 2 of the management system of FIG. 4.

In the next step 12, the stage 1 is implemented to identify the position of the transmission control lever and detect a change in position of the lever.

In the next step 14, the stage 2 is implemented to apply a sign to the speed of the vehicle as a function of the position of the control lever resulting from the change of position.

Then performs a temporal filtering of the speed (step 16) and the setback torque setpoint is calculated by implementing the stage 5 (step 18).

Finally, reference is made to FIG. 7 which illustrates the evolution of the speed of the vehicle (curve A), the evolution of the speed formed by stage 2 (curve B), the identification of the position of the transmission control lever (curve C) and the final anti-reverse setpoint (curve D), as a function of time.

During a first PI phase, the first stage 1 identifies the position of the control lever. The lever is here in reverse position.

During phase P2, the lever is placed in the forward drive position. The anti-reverse system is activated since the vehicle is traveling in the opposite direction to that corresponding to the position of the lever.

Stage 2 authorizes the implementation of the backstop and generates an initialization of the setpoint by stage 5.

The reconditioned speed from the second stage is filtered by stage 4, so as to converge to the current speed, ensuring a gradual application of the anti-reverse setpoint.

During phase P3, the speed formed by stage 2 and the current speed converged. The anti-reverse setpoint gradually decreases until the vehicle is in the correct direction of travel.

Finally, in phase P4, the backstop is deactivated and the setpoint controlled by the driver again becomes equivalent to a rampart setpoint.

The force difference applied to the wheel during the transitions is thus much less thanks to a reset of the speed.

The anti-recoil force value is applied gradually, thanks to the filtering implemented by stage 4.

Claims (1)

Claims [Claim 1] Method for managing a setback torque setpoint applied to the powerplants of a motor vehicle with electric or hybrid traction, characterized in that: - the speed (V) of the vehicle is determined; the position of the transmission control lever is identified and, as soon as a change in position of the lever is detected, - a sign is applied to the vehicle speed as a function of the final position of the control lever; - a temporal filtering of the speed is carried out; and - the anti-reverse torque setpoint is developed from the filtered speed value. [Claim 2] Method according to Claim 1, in which the torque setpoint is produced from maps (6, 7) in which torque values are stored as a function of the speed of the vehicle, for different positions of the control lever. [Claim 3] Method according to either of Claims 1 and 2, in which, during the filtering, the speed value is canceled and then filtered, the filtered value converging towards a real speed value. [Claim 4] The method of any of claims 1 to 3, wherein the speed is measured from the rotational speed of the motor. [Claim 5] The method of claim 4, wherein the speed is measured from the reduction ratio (R) of the differential and the radius (R ’) of the drive wheels. [Claim 6] Method according to any one of Claims 1 to 5, in which a vehicle anti-reverse function is activated if the vehicle is traveling in the opposite direction to that which corresponds to the position of the control lever, and in which the setpoint anti-kickback torque is reduced until the vehicle drives in the direction corresponding to that of the lever. [Claim 7] System for managing a setback torque setpoint applied to the drive wheels of a motor vehicle with electric or hybrid traction, characterized in that it comprises: - means for calculating the vehicle speed; - means (1) for identifying the position of a transmission control lever and detecting a change in position of said lever; - calculation means (2) for applying a sign at the speed of the [Claim 8] vehicle as a function of the final position of the control lever and for temporally filtering the speed, the anti-reverse torque setpoint being produced from the filtered speed value. System according to claim 7, comprising maps (6, 7) in which torque values are stored as a function of the speed of the vehicle, for different positions of the control lever.