TORQUE OSCILLATION CORRECTION DEVICE IN A VEHICLE TRANSMISSION

Abstract

The present invention relates to a device (7) for correcting torque oscillations in a vehicle transmission (3), the transmission (3) being connected to a motor via a primary shaft. The device (7) comprises a torque oscillation correction module configured to deliver a correction torque command based on the primary shaft speed observed by this module. The device (7) is characterized in that this device (7) further comprises a state module configured to determine, during vehicle operation, an operating state from among a set of states comprising a so-called torque stabilized state without backlash, a so-called acceleration state with backlash, and a so-called deceleration state with backlash, and to inform the torque oscillation correction module of this determined state. The module is further configured to adapt the torque oscillation correction according to this determined state. Figure 2

Description

Title of the invention: TORQUE OSCILLATION CORRECTION DEVICE IN A VEHICLE TRANSMISSION

[0001] The present invention relates to the field of controlling transmission oscillations in a vehicle powertrain. More particularly, the invention relates to a device for counteracting oscillations in a vehicle powertrain.

[0002] Figure 1 is a simplified representation of a vehicle transmission. In automotive powertrains, the most significant moments of inertia are, on the one hand, those 11 associated with the engines (internal combustion and / or electric) and the input shaft, and on the other hand, those 12 associated with the wheels. This transmission also includes a reduction gear, Red, arranged between the input shaft and the wheels.

[0003] In this chain of transmission elements, the universal joints are primarily responsible for the transmission's flexibility, followed by the drive shafts. Furthermore, the transmission includes mechanical clearances, Jx, between the input shaft and the wheel, which have a significant effect on the system's response.

[0004] During variations in the torque setpoint Ce given by the driver, certain operating conditions can generate engine speed oscillations with damped oscillatory behavior (the characteristics of this damped oscillatory behavior are modeled by a system comprising a stiffness K and a damping A). These engine speed oscillations are felt by the driver and can cause significant discomfort. Indeed, for example, when the transmitted torque changes direction, contact between the gears or other coupling elements is lost. Then, when the gap between the teeth or coupling elements is re-filled, the gears and / or other relevant components engage with a jolt, which can lead to an abrupt change in the wheel torque Cr delivered, felt by the driver. This loss of contact is referred to by engine manufacturers as backlash.

[0005] In order to eliminate transmission oscillations, it is known, for example from document FR3000993A1, to implement an anti-oscillation controller. This consists of developing a negative feedback proportional to the amplitude of the primary shaft speed oscillations. In this document, it is proposed to distinguish two system states: acceleration with backlash and acceleration without backlash, based on the engine speed gradient and its comparison to a predetermined threshold. However, this document neglects many other modes Operating conditions such as decelerations occurring through or not through play, and torque stabilization below and above play, are challenging. Furthermore, finding an optimal calibration setting for the anti-oscillation controller, valid in all main operating situations, is difficult, especially when the system only distinguishes between the two aforementioned system states.

[0006] There is therefore a need to improve driving comfort in most life situations, whether they involve crossing playgrounds or not.

[0007] To achieve this objective, the invention provides a device for correcting torque oscillations in a vehicle transmission, this vehicle comprising at least one engine for its traction, the transmission being connected to this engine via a primary shaft, this device comprising: -a torque oscillation correction module configured to deliver a correction torque command, based on the primary shaft speed observed by this module, characterized in that this device further comprises a state module configured to determine during the operation of the vehicle a state of operation from among a set of states including a so-called state of torque stabilized without crossing of backlash, a so-called state of accelerations crossing the backlash and a so-called state of decelerations crossing the backlash, and to inform the torque oscillation correction module of this determined state, the module being further configured to adapt the torque oscillation correction according to this determined state.

[0008] The technical effect is to allow a selection of oscillation correction adapted to the nature of the life situation.

[0009] Various additional features may be provided, alone or in combination:

[0010] In one embodiment, the state module is configured to determine the operating state based on compliance with transition conditions between states, these conditions including the comparison of the first derivative with respect to time of the driving torque setpoint has a transition threshold as well as the comparison of the second derivative with respect to time of the driving torque setpoint has another transition threshold.

[0011] In one embodiment, a transition from an initial state to the so-called accelerations-through-the-games state is carried out when the following conditions are met: - the first derivative with respect to time of the driving torque setpoint is greater than a first threshold called the acceleration entry threshold, - the second derivative with respect to time of the driving torque setpoint is greater than a second acceleration entry threshold, - the initial state driving torque setpoint is less than a threshold called backlash.

[0012] In one embodiment, a transition from an initial state to the so-called deceleration state through the gaps is carried out when the following conditions are met: - the first derivative with respect to time of the driving torque setpoint is less than a first threshold called the deceleration exit threshold, - the second derivative with respect to time of the driving torque setpoint is less than a second deceleration entry threshold, - the initial state torque setting is greater than a so-called backlash threshold.

[0013] In one embodiment, the value of the so-called backlash threshold is zero.

[0014] In one embodiment, a transition from the so-called acceleration state through the The transition to a so-called stabilized torque state without through-play is achieved when the following conditions are met: a) the first derivative with respect to time of the driving torque setpoint is less than a first threshold called the acceleration output threshold, b) the second derivative with respect to time of the driving torque setpoint is less than a second acceleration output threshold, - a waiting time in a so-called acceleration state traversing the games since the satisfaction of conditions a) and b) greater than a so-called acceleration waiting threshold.

[0015] In one embodiment, a transition from the so-called deceleration state through the clearances to the so-called torque stabilized state without through clearances is carried out when the following conditions are met: c) the first derivative with respect to time of the driving torque setpoint is greater than a first threshold called the deceleration exit threshold, d) the second derivative with respect to time of the driving torque setpoint is greater than a second deceleration output threshold, - a waiting time in a so-called deceleration state traversing the games since the satisfaction of conditions c) and d) greater than a so-called deceleration waiting threshold.

[0016] In one embodiment, the first threshold, called the acceleration exit threshold, is greater than the first threshold, called the acceleration entry threshold, and the second acceleration entry threshold is greater than the second acceleration exit threshold.

[0017] The invention also relates to a motor vehicle comprising at least one motor for its traction, a transmission being connected to this motor via a primary shaft, characterized in that it comprises a device for correcting torque oscillations in the transmission according to any of the variants previously described.

[0018] Other features and advantages will become apparent from the following description of a particular, non-limiting embodiment of the invention, made with reference to the figures in which:

[0019] [Fig-1] : is a simplified representation of a vehicle transmission.

[0020] [Fig.2]: schematically represents a vehicle comprising a control module for the oscillations of a traction chain according to the invention.

[0021] [Fig.3]: schematically represents the oscillation control module according to the invention.

[0022] [Fig.4]: represents the set of transitions of a state machine, here with three states.

[0023] [Fig.5]: represents in chronogram form a first example of operation with change of state.

[0024] [Fig.6]: represents in the form of a timing diagram a second example of operation with a change of state.

[0025] [Fig.7]: represents in the form of a timing diagram a third example of operation with change of state.

[0026] Figure 2 shows a motor vehicle 1 equipped with a powertrain 2 comprising at least one electric drive unit. Thus, the powertrain can be purely electric with an electric motor or a hybrid electric-thermal engine, with a thermal engine combined with an electric motor.

[0027] The motor group 2 is connected, via a primary shaft (not shown) to a mechanical transmission 3. This mechanical transmission 3 includes means for reducing rotational speed, such as an automated gearbox, or a reducer, which transmits the motor torque to the wheels, via for example a differential 4 and cardan shafts (not shown).

[0028] The electric drive machine of the drive group 2 is powered by a traction battery 5.

[0029] An electronic engine control unit 6 is in charge of the operation of the traction chain 2,3. The unit 6 includes the means for acquisition, processing by software instructions stored in a memory as well as the control means required for the operation of the traction chain, and for the management of the setpoint torque of the motor group 2.

[0030] The computer 6 includes a torque oscillation correction device 7, also referred to as an anti-oscillation controller. As detailed in [Fig. 3], this torque oscillation correction device 7 includes a torque oscillation correction module (MCOR) configured to deliver a correction torque setpoint Ccor. The correction torque setpoint Ccor is determined as a function of the rotational speed, Nm, of the primary shaft of the drive unit 2 observed by this module. Alternatively, the calculation of the correction setpoint Ccor from the difference between the speed of this primary shaft and the speed of the wheel.

[0031] By way of non-limitation, the MCOR module for calculating the correction setpoint Ccor may include several cascaded low-pass and high-pass filters for filtering the observed engine speed Nm and a controller such as a proportional or proportional-derivative controller. In this case, the MCOR module for calculating the correction setpoint Ccor may store the parameters of these filters and the proportional gain of the controller in memory. The filter parameters and the proportional gain of the controller are advantageously established beforehand from engine tests.

[0032] The correction torque command, Ccor, is then subtracted by a subtractor, S, from the requested torque command, Ce, to deliver a final corrected torque, Cf, transmitted to the drive unit 2, which dampens transmission oscillations. The requested torque command, Ce, can originate from the control signal resulting from the driver pressing the accelerator pedal.

[0033] The torque oscillation correction device 7 further comprises a state module, ME,

[0034] In the present case, the state module, ME, is configured to determine during vehicle operation a state of operation defined by three main stresses or states:

[0035] State 0: State of torque stabilization: this refers to accelerations or decelerations where the initial and final torque values ​​are both greater or less than a clearance threshold, this threshold being set at 0 in the present case.

[0036] State 1: State of accelerations crossing the games: this is a torque setpoint whose initial value is less than the game threshold and whose final value is greater than the game threshold.

[0037] State 2: State of decelerations passing through the games: this is a torque instruction whose initial value is greater than the game threshold and whose final value is less than the game threshold.

[0038] In the stabilized state (without any play in the system), the system is fairly linear and its response is homogeneous regardless of the load. However, loads passing through the play behave non-linearly and require careful adjustment.

[0039] The ME state module provides the MCOR correction setpoint calculation module with the determined state value. To optimize the operation of the MCOR correction setpoint calculation module, the filter parameters as well as the proportional gain used to calculate a setpoint value for the correction torque is made dependent on the aforementioned states.

[0040] The MCOR module applies the regulator adapted to the determined state. Thus, when state 0 is determined, the MCOR module configures the regulator with a first set of filter and gain parameters adapted for the stabilized state (state 0).

[0041] When state 1 is determined, the MCOR module configures the controller with a second set of filter and gain parameters adapted for the acceleration state (state 1). When state 2 is determined, the MCOR module configures the controller with a third set of filter and gain parameters adapted for the acceleration state (state 1).

[0042] Figure 4 schematically presents the transitions between the different states. To detect accelerations and decelerations, it is checked whether the gradient of the driving setpoint torque is positive or negative, respectively. However, in order to determine whether the acceleration or deceleration crosses the clearances, the value of the driving setpoint torque at the beginning of the latter is also checked.

[0043] In addition, in order to strengthen the transitions between these three states, a second criterion related to the second derivative of the conducting torque is added.

[0044] Finally, to limit the number of changes of state when the duration of the stabilized state is very short (very close successive accelerations and decelerations), a timer can be integrated to change state without going through the stabilized state.

[0045] The various transition conditions are grouped in the table below. The leftmost column corresponds to the initial state, while the other columns determine the final state based on compliance with the transition conditions defined in the table cells. The transition is effective when all the conditions of the cell in question are met. Final state Initial State Stabilized (0) Stabilized (0) Acceleration (1) G1CC>S1EA Initial State < SJ Deceleration (2) G1CC<S1ED Ce initial > SJ G2CC > S2EA G2CC < S2ED a)GlCC <SlSA G1CC<S1ED Accélération (1) b) G2CC < S2SA Ce initial >SJ Waiting time in G2CC state < S2ED acceleration since the satisfaction of the conditions ns a and b > SDA c) G1CC>S1SD G1CC>S1EA Deceleration (2) d) G2CC > S2SD Ce initial < SJ Waiting time in G2CC state > S2EA deceleration since conditions c and d are met > SDD

[0046] Figure 5 illustrates a first example of a sequence during which the state defined by the state module ME changes value. In Figure 5, the following are represented as a function of time t, from top to bottom: - the driving torque setpoint, Ce, - the first derivative with respect to time of the driving torque setpoint, which we will also refer to as the first gradient, G1CC, - the second derivative with respect to time of the driving torque setpoint, which we will also refer to as the second gradient, G2CC, - the state E defined by the state module ME.

[0047] At time t0, a transition occurs from the initial state 0 to the final state 1, because: - the first gradient of the driving torque setpoint, G ICC, becomes greater than a threshold S1EA, called the first acceleration entry threshold, for which it is considered that the system is entering an acceleration phase that crosses clearances, - the driving torque Ce of the initial state is less than the clearance threshold, SJ. The clearance threshold SJ is defined here as 0, while the driving torque is observed to be less than 0, - the second gradient of the driving torque setpoint, G2CC, becomes greater than a threshold S2EA, called the second acceleration entry threshold, for which it is considered that the system is no longer in the stabilized state. This additional criterion based on the second gradient of the driving torque setpoint strengthens the detection of state changes.

[0048] At time tl, a transition takes place from the initial state 1 to the final state 0, because: - the first gradient of the driving torque setpoint, G ICC, becomes less than a threshold S ISA, called the first acceleration exit threshold, for which it is considered that we exit an acceleration crossing the gaps, - the second gradient of the driving torque setpoint, G2CC, is less than a threshold S2SA, called the second acceleration output threshold, for which it is considered that one enters the stabilized state, - Both of the preceding conditions have been met for a duration threshold SD A, known as the waiting time threshold in the accelerated state. This criterion allows for the establishment of a delay before changing states, ensuring that the preceding conditions have been met for a duration exceeding the waiting time SDA. This waiting time SDA can advantageously be approximately 0.1 seconds, thus preventing unintended state changes.

[0049] At time t2, a transition occurs from the initial state 0 to the final state 2 because: - the first gradient of the driving torque setpoint, G ICC, becomes less than a SIED threshold, called the first deceleration entry threshold, for which it is considered that one enters a deceleration crossing the clearances, - the driving torque Ce of the initial state is greater than the clearance threshold, SJ. The clearance threshold SJ is defined here as 0, while we observe that the driving torque is greater than 0. - The second gradient of the driving torque setpoint, G2CC, falls below a threshold S2ED, called the second deceleration entry threshold, at which point the vehicle is considered to have deviated from its stabilized state. This additional criterion, based on the second gradient of the driving torque setpoint, enhances the detection of state changes.

[0050] At time t3, a transition occurs from the initial state 2 to the final state 0 because: - the first gradient of the driving torque setpoint, G ICC, becomes greater than a threshold SI SD, called the first deceleration exit threshold, for which it is considered that we are exiting a deceleration passing through the gaps, - the second setpoint gradient of driving torque, G2CC, is greater than a threshold S2SD, called the second deceleration exit threshold, for which it is considered that one enters the stabilized state, - Both of the preceding conditions have been met for a duration threshold SDD, also known as the deceleration waiting time threshold. This criterion establishes a delay before changing states, ensuring that the preceding conditions have been met for a period exceeding the waiting time SDD. This waiting time SDD can be approximately 0.1 seconds, therefore in this case equal to SDA, thus preventing unintended state changes.

[0051] In the example in [Fig. 5] and in the following ones, the first acceleration exit threshold (SISA) is greater than the first acceleration entry threshold (S1EA), and the second acceleration entry threshold (S2EA) is greater than the second acceleration exit threshold (S2SA). This calibration choice makes it possible to achieve sufficiently early the change of state from 0 to 1 without untimely returns to state 0 when S1EA < G1CC <s1sa car le seuil s2sa n’est plus vérifié par g2cc.

[0052] Figure 6 illustrates a second example of a sequence in which, during a re-acceleration at time t0, the current state remains at 0 (stabilized state) throughout the transient. This result is consistent with the transition table described above because, for this type of out-of-the-box loading, the controller configured for the stabilized state is applied.

[0053] Figure 7 illustrates a third example of a sequence with rapid mode changes during which the state defined by the state module ME changes value.

[0054] At time t0, a transition occurs from the initial state 2 to the final state 1 because: - the first gradient of the driving torque setpoint, G ICC, becomes greater than the threshold S1EA, called the first acceleration entry threshold, for which it is considered that one enters an acceleration crossing the clearances, - the driving torque Ce of the initial state is less than the clearance threshold, SJ. The clearance threshold SJ is defined here as 0, while we observe that the driving torque is less than 0. - The second gradient of the driving torque setpoint, G2CC, becomes greater than the S2EA threshold, also known as the second acceleration input threshold, at which point the system is considered to have deviated from its stabilized state. This additional criterion, based on the second gradient of the driving torque setpoint, enhances the detection of state changes.

[0055] At time tl, a transition occurs from the initial state 1 to the final state 2 because: - the first gradient of the driving torque setpoint, G ICC, becomes lower than the SIED threshold, called the first deceleration entry threshold, for which it is considered that one enters a deceleration crossing the clearances, - the driving torque Ce of the initial state is greater than the clearance threshold, SJ. The clearance threshold SJ is defined here as 0, while we observe that the driving torque is greater than 0. - The second gradient of the driving torque setpoint, G2CC, falls below a threshold S2ED, called the second deceleration entry threshold, at which point the vehicle is considered to have deviated from its stabilized state. This additional criterion, based on the second gradient of the driving torque setpoint, enhances the detection of state changes.

[0056] The invention improves driving comfort, facilitates function calibration, and enhances robustness by reducing calibration compromises. The invention allows for finding an optimal setting adapted to the driving situation, thereby improving function performance. The invention also allows for reduce the number of state changes in the case of very close successive accelerations and decelerations, while strengthening the transitions between these states.

Claims

Demands

1. A device (7) for correcting torque oscillations in a transmission (3) of a vehicle, the vehicle comprising at least one motor for its traction, the transmission (3) being connected to this motor via a primary shaft, this device (7) comprising: - a torque oscillation correction module (MCOR) configured to deliver a correction torque command (Ccor), based on the primary shaft speed (Nm) observed by this module (MCOR), characterized in that this device (7) further comprises a state module (ME) configured to determine, during vehicle operation, an operating state from among a set of states comprising a so-called torque stabilized state without backlash crossing, a so-called accelerations crossing backlash state, and a so-called decelerations crossing backlash state, and to inform the torque oscillation correction module (MCOR) of this determined state,The module (MCOR) is further configured to adapt the torque oscillation correction according to this determined state.

2. Device (7) according to claim 1, characterized in that the state module (ME) is configured to determine the operating state as a function of compliance with transition conditions between states, these conditions including the comparison of the first derivative with respect to time (G1CC) of the driving torque setpoint (Ce) has a transition threshold as well as the comparison of the second derivative with respect to time (G2CC) of the driving torque setpoint (Ce) has another transition threshold.

3. Device (7) according to claim 2, characterized in that a transition from an initial state to the so-called accelerations through the gaps state is carried out when the following conditions are met: - the first derivative with respect to time (G1CC) of the driving torque setpoint (Ce) is greater than a first threshold called the acceleration entry threshold (S1EA), - the second derivative with respect to time (G2CC) of the driving torque setpoint (Ce) is greater than a second acceleration entry threshold (S2EA), - the initial state torque setpoint (Ce) is less than a threshold called backlash (SJ).

4. Device (7) according to claim 2 or claim 3, characterized in that a transition from an initial state to the so-called deceleration state through the clearances is carried out when the following conditions are met: - the first derivative with respect to time (G1CC) of the driving torque setpoint (Ce) is less than a first threshold called deceleration exit (SIED), - the second derivative with respect to time (G2CC) of the driving torque setpoint (Ce) is less than a second deceleration entry threshold (S2ED), - the driving torque setpoint (Ce) of the initial state is greater than a threshold called clearance (SJ).

5. Device (7) according to claim 3 or 4, characterized in that the value of the so-called game threshold (GTS) is zero.

6. Device (7) according to any one of claims 2 to 5, characterized in that a transition from the so-called clearance-crossing acceleration state to the so-called clearance-crossing torque stabilized state is carried out when the following conditions are met: a. the first time derivative (G1CC) of the driving torque setpoint (Ce) is less than a first acceleration output threshold (SISA), b. the second time derivative (G2CC) of the driving torque setpoint (Ce) is less than a second acceleration output threshold (S2SA), - a waiting time in the so-called clearance-crossing acceleration state since the satisfaction of conditions a) and b) greater than an acceleration waiting threshold (SDA).

7. Device (7) according to any one of claims 2 to 6, characterized in that a transition from the so-called deceleration state crossing the clearances to the so-called torque stabilized state without crossing clearances is carried out when the following conditions are met: a. the first derivative with respect to time (G1CC) of the driving torque setpoint (Ce) is greater than a first threshold called the deceleration exit threshold (SISD), b. the second derivative with respect to time (G2CC) of the driving torque setpoint (Ce) is greater than a second deceleration output threshold (S2SD), - a waiting time in the so-called deceleration state crossing the clearances since the satisfaction of conditions c) and d) greater than a so-called deceleration waiting threshold (SDD).

8. Device (7) according to claims 3 and 6, characterized in that the first threshold called acceleration exit (SISA) is greater than the first threshold called acceleration entry (S1EA) and in that the second acceleration entry threshold (S2EA) is greater than the second acceleration exit threshold (S2SA).

9. Motor vehicle (1) comprising at least one motor for its traction, a transmission (3) being connected to this motor via a primary shaft, characterized in that it comprises a device (7) for correcting torque oscillations in the transmission (3) according to any one of the preceding claims.

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