BR112016023821B1 - DISPLACEMENT CONTROL PROCESS OF A CLUTCH CONTROL ELEMENT - Google Patents

Abstract

PROCESS OF CONTROLLING THE DISPLACEMENT OF A CLUTCH CONTROL ELEMENT. Process of controlling the displacement of a clutch control element by an irreversible drive system composed of an electric drive motor connected by mechanical transmission means to the clutch control element, by sending a reference voltage to the electric motor (Uref ) that depends on a voltage (Ucalc) calculated to minimize the deviation (sigma) between the position (x) of the control element and a reference position (Xref) that must reach the control element, characterized by the fact that the signal The calculated voltage value (Ucalc) is limited in amplitude when the duty deviation (sigma) is greater, in absolute value, than the desired precision (épsilonx) on the reference position (Xref) at the end of the displacement.

Description

[0001] The present invention relates to the field of robotic gearboxes.

[0002] It refers to a process for controlling the position of a clutch on a robotic gearbox for a vehicle equipped with a thermal powertrain (GMP).

[0003] More precisely, this invention has as its object a process for controlling the displacement of a clutch control element by an irreversible drive system composed of an electric drive motor connected by mechanical transmission means to a clutch control element , by sending a reference voltage to the electric motor.

[0004] In a robotized gearbox, the clutch command is ensured by an electrical or hydraulic control system commanded by a computer. The control system is most often composed of an electric drive motor and a movement transmission system towards a rod or a clutch control cable.

[0005] To control the transmission of torque from the heat engine to the gearbox during the opening and closing operations of the clutch, it is necessary to direct with great precision (on the order of 0.1 mm) the position of the cable. The movement transmission system between the electric drive motor 1 and the clutch (not shown) can be composed, in a non-limiting way, according to figure 1: - by a set of pinions 3 allowing to transmit the movement of the motor to a parallel shaft, - by a screw-nut system 4 which transforms the rotational movement of the parallel shaft into a translational movement, - by a cable 2 connected to the screw-nut system 4, which advances on a lever or with a bearing ( not shown), moving the diaphragm away from the clutch, - and by an assistance spring 5, which stores the energy in closing the clutch, and which returns it, helping to open the clutch.

[0006] The particularity of such a transmission system is its irreversibility, linked to the level of strong friction of the screw-nut, which allows keeping the system in position in the event of a cut in the electric motor control (voltage drop, for example ). The irreversibility of the mechanism poses, however, a control problem. Indeed, while the electric motor does not provide a level of effort greater than friction, the system remains immobile, as shown in figure 2, whose curves represent, respectively, the displacement of the clutch bearing as a function of the torque provided by the drive motor. in the direction of clutch closing and opening, for a new clutch, (curves A, B), and for a used clutch (curves C, D). Once the frictions are overcome, the system can move very quickly in. The level of friction can reach values around 70 to 80% of the maximum effort of the electric motor, and this level of friction can vary depending on the wear of the clutch.

[0007] In order to control the transmission of torque from the heat engine to the gearbox, it is not allowed to exceed the position of the cable. This makes the use of classic regulation techniques (such as PID for Derived Integral Proportional) insufficient to correctly treat this type of problem.

[0008] The technical difficulty encountered consists in displacing the clutch cable with a precision of 0.005 mm, without exceeding it, despite the lack of knowledge of the effort that is necessary to apply by the electric motor in order to overcome friction.

[0009] The present invention aims to make the transmission phase of the torque from the heat engine to the gearbox as transparent as possible for users, that is, minimizing sudden torque movements.

[0010] The main difficulties to overcome include: - friction that is not linear, - the static accuracy sought, which is 0.005 mm, and - ensuring small displacements (on the order of 0.1 mm) without overshooting the position, which eliminates the main sources of sudden torque movements when transmitting torque from the heat engine to the box.

[0011] The objective is to implement, in an original command law, a strategy that ensures the displacement of the clutch cable with an accuracy of 0.005 mm, without overshooting the position.

[0012] For this purpose, the invention proposes to limit the calculated voltage signal in amplitude to minimize the deviation between the position of the control element and its reference position, when this deviation is greater, in absolute value, than the desired accuracy on the position reference point at the end of travel.

[0013] Preferably, the calculated voltage signal is saturated over the maximum or minimum voltage of the electric motor, if it is not included between these two values.

[0014] The present invention will be better understood with reference to the following description of a non-limiting embodiment thereof, in connection with the attached drawings, in which:

[0015] - Figure 1 is a schematic of the drive device,

[0016] - Figure 2 illustrates the torque variations of a clutch control actuator,

[0017] - Figure 3 summarizes the proposed command strategy,

[0018] - Figure 4 shows the evolution over time of the clutch position and its reference, and

[0019] - Figure 5 shows the evolution of the trigger reference voltage.

com os dados: co: Regime do motor elétrico; T: Torque do motor elétrico; Td. Torque resistente do motor elétrico (entrada exógena desconhecida, considerada como uma perturbação); J: Inércia do motor elétrico; /: Correndo do induzido do motor elétrico; K: Coeficiente da tensão induzida pelo motor elétrico; R: Resistência do induzido do motor elétrico; L: Indutância do induzido do motor elétrico; Uref. Tensão de referência que se deseja aplicar aos terminais do motor elétrico, compreendido entre Um'n e Umax', Td= f(x) é uma função da posição do cabo da embreagem. Ela depende do esforço aplicado pelo sistema parafuso-porca 4, do esforço da mola de solicitação 5 e do esforço aplicado pelo diafragma da embreagem.[0020] In a clutch actuation system like the one in figure 1, the electric motor can be represented by the following equations:

with the data: co: Electric motor regime; T: Electric motor torque; All Resistant torque of the electric motor (unknown exogenous input, considered as a disturbance); J: Electric motor inertia; /: Running from the armature of the electric motor; K: Coefficient of voltage induced by the electric motor; A: Resistance of the armature of the electric motor; L: Inductance of the armature of the electric motor; Uref. Reference voltage to be applied to the electric motor terminals, between Um'n and Umax', Td= f(x) is a function of the position of the clutch cable. It depends on the effort applied by the screw-nut system 4, the effort of the demand spring 5 and the effort applied by the clutch diaphragm.

de um ponto do cabo da embreagem. O objetivo de comando é deslocar o cabo da embreagem de uma posição inicial x, a uma posição de referência xref, para atender às condições de uma perfeita mudança de relação na caixa de marchas. De acordo com a figura 2, este deslocamento é implementado aplicando ao motor de acionamento uma tensão de referência Uref, de acordo com um processo de comando, que pode ser decomposto em quatro etapas principais. Para controlar o deslocamento do elemento de comando de embreagem, como o cabo de embreagem da figura 1, por um sistema de acionamento irreversível composto de um motor elétrico de acionamento ligado por meios de transmissão mecânicos ao elemento de comando de embreagem, este processo se baseia sobre o envio, ao motor elétrico, da tensão de referência Uref determinada sobre a base de uma tensão Ucalc calculada para minimizar o desvio α entre a posição x do elemento de comando e a posição de referência xref, visada no fim de deslocamento.[0021] The actuator in figure 1 has sensors that allow, with some calculations, to measure the position x (comprised between two bearings: open and closed position) and the speed

from a point on the clutch cable. The command objective is to move the clutch cable from an initial position x, to a reference position xref, in order to meet the conditions for a perfect gear change in the gearbox. According to figure 2, this displacement is implemented by applying a reference voltage Uref to the drive motor, according to a command process, which can be decomposed into four main steps. In order to control the displacement of the clutch control element, such as the clutch cable in figure 1, by an irreversible drive system composed of an electric drive motor connected by mechanical transmission means to the clutch control element, this process is based on on sending to the electric motor the reference voltage Uref determined on the basis of a voltage Ucalc calculated to minimize the deviation α between the position x of the control element and the reference position xref, aimed at the end of the movement.

[0022] A first step is to produce a first calculated voltage signal Ucalc, which is saturated over the maximum Umax or minimum Umax voltage of the electric motor, if it is not between these two values. To elaborate Ucalc, the reference signal xret, (setting point of the clutch cable position) is compared with the measured signal x (instantaneous position of the cable). The voltage applied to the drive motor depends on the sign and magnitude of the position deviation o = x - Xret, and on two calibrated parameters, εx, and α > 1. εx represents the position error tolerated in relation to the reference, or range tolerated over the position around its target, α is a reduction coefficient applied to the voltage calculated Ucalc as follows.

[0023] When the position deviation o is greater, in absolute value, than the desired precision εx on the reference position Xrerem end of displacement (<j > εx or a < - εx), the calculated voltage is weighted by the calibrated coefficient α greater than or equal to 1. The signal then takes on values equal to the ratio of the maximum stress Uma* and minimum Umin of the traction machine over a calibrated limitation coefficient a. The Umax/cr or Umin/cr values determine the usable voltage range for shifting the clutch control.

[0024] When the deviation a is lower in absolute value than the desired precision εx, the calculated voltage Ucalc is leveled by applying to it, for example, a formula of the type:

, ap|jca_se 0 coeficiente β ao sinal de tensão calculado Ucalc, com

. O sinal se torna Ucalc* = β Ucalc, como indicado na figura 3. Senão, Ucalc* = Ucalc.[0025] A second step consists of regulating the calculated voltage signal t/ca/c. To produce the regulated signal Ucalc*, a calibrated regulation coefficient β with (0 < β < 1) is applied to Ucalc or not, depending on whether or not the system has the necessary energy to move the control over the remaining distance α to the target x«f. This operation aims to lock the clutch command upon its arrival over the xref position adjustment point. If the energy is sufficient, the energy is reduced (even cutting it in an extreme situation) to avoid eventually exceeding the xref target. If the deviation α is greater, in absolute value, than the tolerated position error

, apply the β coefficient to the calculated voltage signal Ucalc, with

. The signal becomes Ucalc* = β Ucalc, as shown in figure 3. Otherwise, Ucalc* = Ucalc.

neste caso,

nulo. Senão,

,eo termo de correção integrado é nulo também.[0026] A third step is to add an integrated term to the Ucalc* signal if the position deviation a is between - εx and εx. The calculated voltage t/ca/c Ucalc* is corrected by integrating the deviation a with a non-zero calibrated gain Ki, when this deviation is lower, in absolute value, than the accuracy εx This originality of the invention is based on activation or deactivation of the integration of the deviation a (multiplied by the calibrated gain Ki), when this deviation is smaller, in absolute value, than the precision εx. if

in this case,

null. If no,

,and the built-in correction term is also zero.

[0027] A fourth phase consists of supervising the Ucalc** corrected signal in a saturator, to see if this signal is between the Umin and Umax values. If this is not the case, the boolean G of the saturator is equal to 1, and the integrator is blocked. This circuit, called Uanti-wind-up", makes it possible to suppress the integration term to saturate Ucalc **. Thanks to this measure, the reference voltage Uref coming from the limiter is always between the maximum voltage Umax and minimum voltage Umin of the motor electric 1.

[0028] In conclusion, the proposed strategy allows to reduce the position deviation very quickly to reach an accuracy of about 0.005 mm, without overshooting the position. This result is highlighted in figures 4 and 5, which represent, on the one hand, the evolution over time of the position of the command x and its reference set point xref and, on the other hand, the corresponding evolution of the reference voltage Uref. The process of the invention therefore makes it possible to transmit the torque from the heat engine to the gearbox practically without sudden torque movements. Finally, the convergence to the target position does not depend, in any case, on the intrinsic parameters of the system, such as the inertia and the trigger response time and eventual delay, which makes this strategy particularly robust.

Claims (7)

1. Process of controlling the displacement of a clutch control element by an irreversible drive system composed of an electric drive motor connected by mechanical transmission means to the clutch control element, by sending a reference voltage to the electric motor (t/feZ) based on a voltage (t/cate) calculated to minimize the deviation (o) between the position (x) of the control element and a reference position (xref) which the control element must reach, at which a first calculated voltage signal (Ucalc) is limited in amplitude when the position deviation (o) is greater, in absolute value, than the desired accuracy (εx) on the reference position (xrer) at the end of the displacement, characterized by the fact that the first calculated voltage signal (t/ca/c) Q is saturated over the maximum (Umax) or minimum (Umax) voltage of the electric motor, if it is not included between these two values. 2. Control process according to claim 1, characterized by the fact that the amplitude of the calculated voltage signal (Ucalc) is limited between values equal to the maximum (Umax) and minimum (Um'n) torque ratio of the electric motor , on a calibrated limitation coefficient (or), when the deviation (o) is greater, in absolute value, than the desired precision (εx) on the reference position (Xref). 3. Control process according to claim 1 or 2, characterized in that the calculated voltage (Ucalc) is leveled when the deviation (o) is lower in absolute value than the desired precision (εx) on the reference position (xrer). 4. Control process according to claim 2 or 3, characterized in that if the absolute value of the deviation (o) is less than the precision (εx), a calibrated regulation coefficient (β) between 0 and 1, in the calculated voltage (Ucalc), which becomes Ucalc* = β Ucalc. 5. Control process according to claim 4, characterized in that the calculated voltage (Ucalc' Ucalc') is corrected by integrating the deviation (o) with a non-zero calibrated gain (Ki), when this deviation is lower in absolute value than the precision (εx). 6. Control process according to one of the preceding claims, characterized in that the reference voltage (Uref) applied to the electric motor is obtained by limiting the corrected voltage (Ucalc' Ucalc") between the maximum voltage values (Umax) and minimum voltage ((J™n) of the electric motor. 7. Control process according to claim 5 or 6, characterized by the fact that the integrator is blocked if the corrected signal (JJcalc **) is not included between the Umin and Umax values.

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