WO2010061100A2

WO2010061100A2 - Method and device for controlling a mechanical actuator with a progressivity mechanism

Info

Publication number: WO2010061100A2
Application number: PCT/FR2009/052225
Authority: WO
Inventors: Edouard Negre
Original assignee: Renault S.A.S.
Priority date: 2008-11-27
Filing date: 2009-11-19
Publication date: 2010-06-03
Also published as: FR2938938A1; WO2010061100A3

Abstract

The invention relates to a control device (16) for a mechanical actuator (1) with a progressivity mechanism (4) for the force transmitted to an actuator interface (12). The device includes a means (17) for calculating a position setting of an actuator drive motor. Said calculation means (17) is connected to a means for determining a force setting (F*(t)) to be applied by the actuator interface (12) of the actuator. Said calculation means is suitable for calculating a first motor position setting (? 1*(t)) according to said force setting.

Description

Method and device for controlling a mechanical actuator with progressive mechanism

The invention relates to the field of actuators such as actuators, including actuators for transmission or gearbox of a motor vehicle and in particular the methods and devices for controlling such actuators.

Such actuators act by a finger driven in translation and / or in rotation by an electric drive motor. The finger cooperates with transmission members such as dry disk clutches and elastic diaphragm clutches, multi-disk oil clutches, clutch synchronizers, cone or friction disk couplers, transmission mode changing devices. or brakes. In general, the actuated members comprise a body whose change of position is accompanied by a change of state of the organ. The finger of the actuator must exert a force on the body of the organ to change the state of said body.

Activation of certain actuators consists in maintaining a supply voltage of the motor until a limit switch indicates that the transition has taken place. Such actuators are not suitable for members requiring a large actuating force over a reduced distance of the transition stroke.

Indeed, some clutch synchronizers are equipped with devices known as "prohibition" that block the translation of the player as rotational speeds on both sides of the device are not equal. The force exerted by the player on a lever causes relative braking between the freewheel and the hub of the synchronizer. When the latter are synchronous, the prohibition device retracts and the player continues its translation by cooperating with jaw of the freewheel. In other words, the actuation of such a synchronizer comprises, successively, an approach phase, a relative braking phase and a braking phase. interconnection. In this phase of braking, or synchronization, the player does not move but the actuating force must be controlled and precisely controlled.

The invention relates in particular to actuators equipped with a progressivity mechanism used in particular for synchronizers with clutch, and allowing the limitation and / or control of the actuating force in the braking phase.

Patent application FR 2 861 153 describes such an actuator. This includes an electric motor and a spring located between the electric motor and the output shaft of the actuator which may be the fork shaft, or a control shaft. In this actuator, the progressivity mechanism acts as a force limiter exerted by the output rod. When the output rod pushes the dog synchronizer of the previously described synchronizer, the force exerted by the actuator increases at the moment the interdiction device blocks the player, and is reduced during the phase of interconnection. This effort is limited by the distortion of the mechanism of progressiveness.

The disadvantage of such an actuator equipped with a progressive mechanism is that the effort limitation is fixed. This is not suitable for driving members with different actuation profiles. For example, such actuators are not adapted to actuate a clutch in a select position and a clutch synchronizer in another direction of operation or another selection position.

Another application also needs to adapt to different conditions of use. When a vehicle driver wants a fast acceleration of the vehicle, for example when passing, the duration of the ratio transitions must be as short as possible. Friction coupling members are then strongly stressed and can wear out. When the same transition of relationship takes place in a more serene context, it is a pity that the duration of transition is the same. It is advantageous to reduce the wear of the coupling members. The invention proposes a method and a device for controlling a mechanical actuator with a progressive mechanism that overcomes the aforementioned drawbacks and in particular, which improves the possibility of the actuator adapting to a wider range of use.

According to one embodiment, the control device is suitable for a mechanical actuator with a mechanism for progressivity of the force transmitted to an actuating interface. The device comprises means for calculating a position setpoint of a drive motor of the actuator. Said calculation means is connected to means for determining a force setpoint to be applied by the actuator operating interface. Said calculation means is capable of calculating a first motor position setpoint as a function of said effort setpoint. The fact of taking into account a force reference to determine the motor position setpoint makes it possible to control the motor of the actuator in a manner adapted to the circumstances and the type of member to be actuated. For example, in the aforementioned case of friction coupling member, a high set of effort to be applied will be preferred when rapid acceleration is desired, and a moderate effort setpoint will preserve the life of the coupling member.

Advantageously, the device comprises a first position sensor of a dynamically located element of the actuator upstream of the progressivity mechanism and a second position sensor of the actuator actuation interface, the first and second sensors being related to the calculation means.

Advantageously, the means for calculating the motor position setpoint is connected to a force / stroke mapping of the actuator and in particular to the effort / stroke mapping of the progressivity mechanism.

The fact of measuring the position upstream and downstream of the progressivity mechanism makes it possible to know at any time the position of the actuation interface and the force exerted by the stress / strain mapping.

According to one embodiment, the device is suitable for an actuator having a mechanical clearance internal to the actuator or in the controlled mechanism. The calculation means is connected to a means for determining said mechanical clearance.

Advantageously, the means for calculating the first motor position setpoint comprises a first-order filter with a positive offset of the initial reaction of the filter greater than the mechanical half-play.

When the kinematic chain between the motor and the actuation interface has a mechanical clearance, the passage of a force exerted substantially zero to a force exerted according to the setpoint, has a time offset corresponding to the time required for the motor to travel the mechanical game. The fact of using a filter with a positive offset of the intensity of the initial reaction of the filter makes it possible to reduce this time shift without modifying the convergence of the servocontrol of the action towards the effort setpoint to exert.

According to one embodiment, the device comprises a means for determining a position setpoint of the actuator operating interface, a means for calculating a second position setpoint of the drive motor of the actuator. actuator according to said position setpoint and means for selecting the first or the second motor position setpoint to be applied. Advantageously, the means for calculating the second motor position setpoint comprises a first-order filter.

When actuated, the stiffness changes of the actuated member disturb the drive of the actuating interface due to the progressive mechanism of the actuator. For example, for the actuation of a dry clutch with diaphragm, the coupled state of a clutch takes place for a given position of the actuator. In other words, the position reference of the actuating interface corresponding to the engagement of the clutch is in the form of a rung. The filter optimizes the race of the actuation interface without causing jolts in the effort to be exerted. This makes it possible to reduce the variations in deformation of the progressivity mechanism and the associated perturbation for the servo controller. Thus, the filter makes it possible to prevent the progressiveness mechanism from oscillating.

According to one embodiment, the device comprises a system for controlling the position of the engine, able to receive the motor position setpoint and to actuate the drive motor of the actuator as a function of limiting parameters of the motor. This allows the actual motor control current to take into account such parameters as thermal protection, phase current limitation or miscellaneous fault management. This also allows the initialization of the motor position measurement.

According to another aspect, the invention also relates to a mechanical actuator comprising a control device. The actuator further comprises means for guiding the actuating interface in translation and an elastic spring performing the progressivity function. One end of said spring is attached to the actuating interface and the other end is translationally driven by an electric drive motor.

According to another aspect, the invention also relates to a gearbox comprising a mechanical actuator with progressivity mechanism of the force transmitted to an actuating interface, the actuator being controlled by the control device. The actuation interface may be a control finger, a fork or a fork dog.

According to one embodiment, the gearbox comprises a clutch with elastic diaphragm and a friction cone synchronizer, actuated by the same actuator and comprises a device for controlling said actuator. Advantageously, the control device chooses to actuate the friction cone synchronizer from the first motor position setpoint and to actuate the diaphragm clutch from the second motor position setpoint. Thus, the same actuator can actuate bodies having different actuation requirements.

According to one embodiment, the gearbox comprises a clutch synchronizer and interdiction device and a friction cone synchronizer, actuated by the same actuator and comprising a device for controlling said actuator.

According to another aspect, the invention also relates to a method for controlling a mechanical actuator with a progressivity mechanism, in which a position setpoint of a drive motor of the actuator is calculated, characterized in that it comprises at least a first calculation mode taking into account a force setpoint to be applied by the actuator.

Advantageously, a calculation mode is chosen to be applied to the motor position setpoint among at least three possible calculation modes, a second possible calculation mode taking into account a position reference of the actuator operating interface, and a third possible calculation mode taking into account, alternatively, a position setpoint of the actuation interface and a force setpoint to be applied by the actuator. Advantageously, the first calculation mode is chosen for controlling a friction coupling coupler actuator.

Advantageously, the second method of calculation is chosen to control a clutch actuator with an elastic diaphragm.

Advantageously, the third method of calculation is chosen to drive a dog synchronizer and interdiction device.

Advantageously, the third mixed calculation mode presents a calculation phase as a function of a force reference during the synchronization phase under the effect of the interdiction device, preceded and / or followed by a calculation phase based on a position command or speed of the finger, corresponding to the phases of approach and / or interconnection of the synchronizer.

According to one embodiment, the position of an element of the dynamically located actuator is measured over time. of the progressivity mechanism and the position of the operating interface of the actuator.

Advantageously, when the calculation takes into account a force setpoint applied by the actuating interface, the mechanical play of the actuator is also taken into account.

Advantageously, the calculation takes into account a mapping of the value of the force applied by the actuating interface as a function of the deformation of the progressive mechanism, and therefore as a function of the variation, with respect to the state of the actuator at rest, the distance between the upstream element and the actuator interface of the actuator.

Advantageously, the dynamic friction of the actuator is taken into account by using a first order filter.

Advantageously, when the calculation takes into account a position setpoint of the actuation interface, the dynamic friction of the actuator is also taken into account by using a first order filter.

Other characteristics and advantages of the invention will appear on reading the detailed description of an embodiment taken by way of non-limiting example and illustrated by the appended drawing, in which FIG. 1 is a diagram of a actuator, two actuable members and the actuator control device.

As illustrated in FIG. 1, the actuator 1 comprises a drive geared motor 2, a translation guide means 3 and a progressivity mechanism 4. The drive geared motor 2 comprises an electric motor 5, a geared gearbox 6 and a control system 7 of the motor supply 5. The gear reducer 6 drives a worm 8 on which is mounted a nut 9 immobilized in rotation by a groove and a key conjugate

10 extending longitudinally in the axis of the worm 8. The translation guiding means 3 of the nut 9 is constituted by the worm 8 and the groove / key system 10. Any other mechanical means allowing to transform the rotation of the electric motor 5 in translation of the nut 9 is suitable. The progressivity mechanism could also be a torsional stiffness device and operate by angular rather than linear deformation. In this case, the guide is no longer produced according to a translation movement but rotation.

The progressivity mechanism 4 comprises a spring 1 1 and a hub 12 guided in translation by the worm 8. Advantageously, a groove / keyway system 10a makes it possible to prevent the hub 12 from rotating. The hub 12 also comprises a drive pin 12a and constitutes an actuating interface 12 of the actuator. Depending on the position of the finger 12a, the actuating interface 12 may cause either a friction cone synchronizer 13 or a dry diaphragm clutch 14 through forks 15 and 15a. The kinematic chain connecting the electric motor 5 to the forks 15 or 15a therefore comprises successively the gear reducer, the worm 8, the nut 9, the spring 1 1 and the actuating interface 12. Along this chain kinematics, many mechanical games can occur: inside the gear reducer 6, between the nut 9 and the screw 8, between the actuating interface 12 and the fork 15 or 15a.

We will now describe the device and the control method of the actuator described above. Such a control makes it possible in particular to reduce the time offsets despite the existence of mechanical games in the kinematic chain. The control device also makes it possible to control the force exerted and / or the position of the actuating interface 12 despite the presence of the progressivity mechanism 4.

The control device 16 comprises a calculation means 17, a determination means 18 of a position command x * of the actuation interface 12, a means 19 for determining a force set point F * to be exerted. by the operating interface 12, a selection means 20 of the calculation mode to be applied. The calculation means 17 also comprises a map 21 of the type Actuating force / deformation of the actuator 1. The control device 16 also comprises an upstream sensor 22 for measuring a position P l (t) of the nut 9 dynamically located upstream of the progressivity mechanism 4 and a downstream sensor 23 located downstream of the spring 1 and making it possible to measure the position P2 (t) of the actuating interface 12 along the driving axis of the worm 8.

We will now describe the different modes of calculation. In a first calculation mode, the calculation means 17 receives the instruction

F * force to be applied by the actuating interface 12. ¹ ^> is the setpoint of the position of the motor 5 to calculate. P l (t) and P2 (t) are the positions measured at time t by the upstream and downstream sensors respectively 23. L is the neutral length separating the upstream and downstream sensors 22, 23 when the spring 1 1 is relaxed . ε (t) is the instantaneous deformation of the spring 1 1. ε (t) is positive if the spring is compressed and negative if the spring is extended. We have :

P2 (t) - Pl (t) = L - ε (t) (1)

If λ is the coefficient of proportionality of the gear reducer 6 and the screw-nut system 8, 9, we have:

θ {t) = λ.P \ {t) (2)

Finally, J is the cumulative mechanical game over the entire kinematic chain between the two parts whose positions are measured. K is the stiffness of the spring 1 1. F (t) is the force applied by the actuating interface 12. We have:

Nonlinearities of the progressivity mechanism 4 may also be taken into account by the general formula:

ε {t) = f [F {ή] (4) The instantaneous setpoint of position θ * (t) of the electric motor 5, in the case of an actuator with mechanical clearance J and linear behavior of the progressivity mechanism 4 is therefore:

e; (t) = λ. (P2 ( _t ) - L) + - + - (5) 2 K

(P2 (t) -L) represents the position of the nut 9 if no force is transmitted by the spring 1 1 and ε (t) represents the compression of the spring 1 1.

In the case of a non-linear behavior of the progressivity mechanism, with or without play, the position setpoint θ * (t) of the motor is given by the formula:

θ; (t) = λ. [(P2 (t) -L) ₊ f [Fi (6)

The function f is supplied to the calculation means 17 by the map 21.

It is also possible to take into account the inertia of the moving parts and the friction between the components by introducing a first-order filter in the calculation of the position setpoint of the motor 5. This is then given by the formula:

where p is the frequency variable of the place usually used to model the dynamic behavior of a system. D is an initial offset of the reaction of the first order filter. D is greater than - so that the initial value of the setpoint of motor position makes it possible to quickly pass the mechanical clearance and to start compressing or relaxing the spring 1 1.

We will now describe a second calculation mode in which a second motor position setpoint θ t) is calculated from a setpoint x * of the position of the actuating interface 12. The static calculation of this instantaneous setpoint can be given by:

θ; (t) = λ. [ _x ; _t) - (P2 (t) - pi (t))] (8)

It is also possible to take into account the friction and the inertia of the components by introducing a first order filter in the calculation of the motor position setpoint:

We will now describe a third mixed calculation mode suitable for a synchronizer clutch and brake lever. During a first period of time corresponding to an approach phase of the player, the selection means 20 instructs the calculation means 17 to calculate the position setpoint θ of the motor as a function of a position command x * according to FIG. one or the other of the two formulas (8) or (9). The position setpoint x then corresponds to the position where a player of the synchronizer begins to push the brake lever. Thus, thanks to a control according to a position setpoint, the player is quickly in contact with the brake lever. From this position, it is no longer possible for the player to continue to advance because the lever blocks the progression of the player until the relative speed of the hub and the wheel concerned is synchronized.

In a second period of time corresponding to a sync phase of the synchronizer, the selection means 20 switches then on the second calculation mode and imposes on the calculation means 17 to generate a position setpoint θjy engine as a function of a setpoint of effort F. This set of effort is higher or lower depending on the speed with which circumstances require to synchronize the synchronizer hub and the wheel concerned. The fact of going from a control phase by position command to a control by force reference to be applied allows to control this effort without the risk of degrading the drive motor 2 of the actuator. Finally, in a third period of time, once the synchronization between the hub and the wheel concerned, the selection means 20 returns to a motor control position by position. This corresponds to a phase of interconnection. Steering in position is better because the phase of interconnection must be fast and requires a moderate effort of the actuator. In addition, control of the condition of the friction cone synchronizer is guaranteed when the player arrives at a known final position, and this with a controlled speed and without residual thrust force, so as not to cause shock between the player and its limit stop. In this third case, the realization of transitions between the two modes of calculation of the motor position setpoint θ * _(t) , respectively from the position setpoints x *, supplied by the determination means 18, and of the effort F * provided by the determination means 18, can generate difficulties of initialization calculations and stability.

Advantageously, it is possible to perform the two calculation modes simultaneously and to arbitrate the results by simple saturation, by applying the lowest position reference value θ (t) motor. By this method, the position x * and the force F * are simultaneously controlled by mutual limitation of the two setpoints.

Claims

A driving device (16) for a mechanical actuator (1) with a mechanism for progressivity (4) of the force transmitted to an actuating interface (2), comprising a first position sensor (22) of an element ( 9) of the actuator (1) located dynamically upstream of the progressivity mechanism (4) and a second position sensor (23) of an actuating interface (12) of the actuator (1), the first and second sensors (22, 23) being connected to a calculation means (17) of a position setpoint of a drive motor (2) of the actuator (1), which is connected on the one hand to a effort / travel mapping (21) of the progressivity mechanism (4) and on the other hand to a means (19) for determining a setpoint

(F ^{* force} ^ W) 'to be applied by the actuator operating interface (12), and which is capable of calculating a first motor position setpoint ^ ¹ ^ >> according to said setpoint d stress ^ ^, characterized in that the calculating means (17) is connected to a means for determining the mechanical play of the actuator (1).

2. Device according to claim 1, wherein the means for calculating the first motor position set ^ ¹ >> comprises a first order filter with a positive offset (D) of the reaction of the upper filter to the mechanical half-game. .

3. Device according to one of claims 1 or 2, comprising means for determining a position command (x *) of the actuator interface (12) of the actuator (1), a calculation means (17) a second instruction v ^y 2W / d _e position of the drive motor (2) of the actuator according to said position setpoint (x *) and a selection means (20) of the first or the second motor position setpoint to be applied v ^y iv ^t Λ ^y 2V ^t // _>

4. Device according to claim 3, wherein the means for calculating the second motor position set v ^y 2W / comprises a first-order filter.

5. Device according to one of claims 1 to 4, comprising a control system (7) of the engine position, adapted to receive the engine position command v ^y iw> ^y 2W / _e t to actuate the engine d drive (2) of the actuator according to limiting parameters of the motor (2).

6. Mechanical actuator (1) comprising a control device (16) according to one of the preceding claims, a means for translational guidance (3) of the actuating interface (12) and an elastic spring (11). ), one end of said spring (11) being fixed to the actuating interface (12) and the other end being driven in translation by an electric drive motor (5).

7. Gearbox comprising a clutch with elastic diaphragm (14) and a friction cone synchronizer (13) actuated by the same actuator and comprising a device for controlling said actuator according to one of claims 1 to 5.

8. A gearbox comprising a clutch synchronizer and prohibition device and a friction cone synchronizer, actuated by the same actuator (1) and comprising a control device (16) of said actuator according to one of claims 1 to 5.

9. A method for controlling a mechanical actuator with a progressivity mechanism, in which a position setpoint v "i v '// of a drive motor (2) of the actuator (1), comprising less a first calculation mode taking into account a force instruction

the actuator (1), characterized by the fact that a calculation mode mode is chosen to be applied to the motor position setpoint taking into account both a position set ^ ^x ^ >> of the interface d actuation (12) of the actuator, and a force reference vw / to be applied by the actuator (1), the result of the two calculations being arbitrated by mutual saturation.