DE102012204940A1 - Method for adapting parameters of a coupling - Google Patents

Abstract

Method for adapting parameters of a clutch of a double clutch transmission system, which has a hydrostatic clutch actuator with a pressure sensor, in a motor vehicle.

Description

The invention relates to a method having the features according to the preamble of claim 1.

The invention serves to determine the adaptive parameters of a hydrostatic clutch system at the belt end.

In particular, the adaptation of parameters of a clutch of a dual-clutch transmission with a hydrostatic clutch system is described by the present invention. Hydrostatic clutch systems are designed with a clutch actuator having a pressure sensor, this is for example in 1 , in the DE 10 2010 047 800 A1 as well as the DE 10 2010 047 801 A1 shown. The clutch actuator is a so-called hydrostatic clutch actuator HCA (Hydrostatic Clutch Actuator). Under such a hydrostatic actuator is an actuator with a hydrostatic transmission path, for example, a pressure line with hydraulic fluid to understand. The pressure in the pressure line is detected by the pressure sensor. If an associated element is to be moved by the hydrostatic actuator, hydraulic fluid is moved in the transmission path or the pressure line, for example caused by a piston in a master cylinder, which moves a piston in a slave cylinder coupled by the hydraulic fluid. If the element is to hold its position, the hydraulic fluid in the transmission path rests so that there is a hydrostatic state of the hydraulic fluid that gives its name to this actuator.

Usually, the commissioning of dual-clutch transmissions - as they are for example in the DE 10 2010 012 756 A1 is shown - consuming and is done with the help of torque signals. A prerequisite for complete commissioning is generally a transmission test bench or chassis dynamometer, which results in high costs. In addition, there is a dependency on the accuracy of external torque signals.

The torque which can be transmitted by a clutch depends in particular on the path-clamping force characteristic curve. How such a path-clamping force characteristic curve can be learned with the aid of a pressure sensor signal during commissioning is described, for example, in the German patent application DE 10 2011 081 195 described.

The modeling of the displacement-clamping force characteristic is based on a simple nominal displacement-force characteristic, which is characterized by the following parameters: - touch point: Coupling position, where a given small moment (eg 5Nm) or its equivalent force can be transmitted. - stiffness: Scaling factor with which the slope of the path-clamping force characteristic can be changed. - Form factors: Scaling factors that can be used to change the force values at the waypoints above the touch point. - leaf spring preload: Leaf spring force with the clutch open (snub hole in the hydraulic section closed, however)

The determination of these adaptive parameters at the end of the tape already allows a high torque accuracy and thus a high level of ride comfort during initial use. In order to maintain this over life, the adaptive parameters listed above are also adapted while driving by algorithms for both clutches.

The two terms position-pressure curve and path-pressure curve and the two terms position-force curve and path-force curve are used interchangeably in this document. The terms path or position refer to the Aktorweg along which, the clutch moving part of the actuator - for example, a piston in the master cylinder - moves.

The above-mentioned German patent application DE 10 2011 081 195 however, does not describe the learning process for the adaptive parameters listed above with sufficient accuracy. In addition, there are other adaptive parameters whose learning process in the German patent application DE 10 2011 081 195.8 not described.

All coupling parameters must be determined as best as possible during commissioning at the end of the belt (vehicle or test stand) or in the service, so that these can be stored in the EEprom memory for further use while driving.

It is therefore an object of the present invention to provide a method for the adaptation of clutch parameters of a dual-clutch transmission, which is inexpensive to use, and preferably manages without a transmission tester or chassis dynamometer.

The object is achieved by a method having the features according to claim 1.

• – Schließen und/oder Öffnen der Kupplung,
• – Erfassen eines Druckverlaufs mittels des Drucksensors sowie der Position der Kupplung während dem Schließen und/oder Öffnen der Kupplung,
• – Adaption der Parameter für die Kupplung aus dem Druckverlauf und
• – Verwenden der adaptierten Parameter im anschließenden Betrieb der Kupplung.

According to the invention, a method for adapting parameters of a clutch of a dual-clutch transmission system, which has a hydrostatic clutch actuator with a pressure sensor, is provided in a motor vehicle. According to the invention, it is provided that the following steps are carried out:

• Closing and / or opening the coupling,
• Detecting a pressure profile by means of the pressure sensor and the position of the clutch during the closing and / or opening of the clutch,
• - Adaptation of the parameters for the clutch from the pressure curve and
• - Use the adapted parameters in the subsequent operation of the coupling.

With the method according to the invention, the parameter adaptation can also take place without a transmission test bench.

In a particularly preferred embodiment of the invention, it is provided that the adaptation of the parameters during initial commissioning of the dual-clutch transmission system and / or recommissioning of the dual-clutch transmission system and / or commissioning of the vehicle and / or decommissioning of the vehicle, in particular in the wake and / or during driving of the vehicle The parameters are "base pressure hysteresis", "pressure-pressure hysteresis", "touch point", "stiffness", "shape factors", "leaf spring force preload".

In a further preferred embodiment of the invention, it is provided that the clutch is retracted to a predetermined threshold value of the pressure and is then fully driven up again and / or that the clutch is driven up to a predetermined threshold value of the pressure and then completely closed again.

In a further preferred embodiment of the invention it is provided that from the detected pressure curve, a path-pressure characteristic of the clutch is determined, and that from the determined path-pressure curve a path-engaging force characteristic of the clutch is determined and that in the Position range of the Weg-Einrückkraft characteristic curve in which the clutch is operated in the region of the clearance and still does not transmit torque, an approximation is performed with a straight line representing a Weg leaf spring force characteristic, wherein from the Weg leaf spring force characteristic of the parameter "Leaf spring force preload" as the function value of the straight line at a position at which the clutch is fully open and no torque is transmitted and the piston in the slave cylinder has passed the sniffer opening in the direction of the clutch closing, so that no connection of the pressure medium to the expansion tank is detected.

In a further preferred embodiment of the invention it is provided that from the detected pressure curve, a path-pressure curve for closing the clutch and a path-pressure curve for opening the clutch at predetermined position support points, where then path-pressure value pairs be present and that the parameter "basic pressure hysteresis" as an average of the differences of the path-pressure curve for closing and the path-pressure curve for opening at the position support points, which are in a position range in which the path Pressure curves have a gradient that is smaller than a predetermined minimum gradient threshold is determined.

In a further preferred embodiment of the invention it is provided that the parameter "pressure-pressure hysteresis" as differences of the value of the path-pressure characteristic for the closing and the value of the path-pressure characteristic for the opening, with maximum actuator position in the direction of coupling Close, is determined.

In a further preferred embodiment of the invention, it is provided that a clamping force characteristic of the clutch is determined by subtracting the determined path-leaf spring force characteristic of the clutch from the determined path-engaging force characteristic of the clutch.

In a further preferred embodiment of the invention, it is provided that the parameter "touch point position" is determined by interpolation of the determined clamping force characteristic for a given contact point force, wherein upon specification of a Tastpunktmoments a conversion into a corresponding force occurs.

In a further preferred embodiment of the invention, it is provided that the clamping force characteristic of the coupling is displaced in the position direction such that the predetermined position on the position axis corresponding to the touch point corresponds to the determined parameter "touch point position" and at position reference points at which path-pressure value pairs in each case the quotient of two force values is determined, wherein in each case one force value is determined as interpolation of the determined clamping force characteristic and respectively the second force value as interpolation of the shifted clamping force characteristic and wherein the value of the quotient respectively a parameter of "preliminary form factors" is.

In a further preferred embodiment of the invention, it is provided that the parameter "rigidity" is determined as the mean value from the determined parameters of the "preliminary form factors".

In a further preferred embodiment of the invention, it is provided that the parameters "final shape factors" are determined from the parameters "preliminary shape factors" by subtracting the parameter "rigidity".

In a further preferred embodiment of the invention, it is provided that a scaling factor is additionally taken into account when determining the parameters.

In a further preferred embodiment of the invention, it is provided that the relationship between the clamping force of the clutch and the torque which can be transmitted by the clutch is detected by means of a torque signal during commissioning or in the subsequent operation of the clutch.

Further advantages and advantageous embodiments of the invention are the subject of the following figures and their description.

1 schematic structure of a hydrostatic coupling system

2 Off-pressure characteristic curve

3 Modeling: Distance-pressure curve with pressure hysteresis

4 Identification of the adaptive parameters of the pressure hysteresis

5 Determination of the clamping force characteristic

In 1 is schematically the structure of a hydraulic coupling system 1 illustrated by the example of the prior art, schematically illustrated hydraulic hydrostatic clutch actuator (HCA). This schematic diagram shows only the structure for operating one of the two clutches of a dual-clutch transmission, the operation of the second clutch is analog. The hydraulic coupling system 1 includes on the donor side 15 a control unit 2 that an actor 3 controls. At a change in position of the actuator 3 and the piston 19 in the cylinder 4 along the Aktorweges to the right is the volume of the cylinder 4 changed, creating a pressure P in the cylinder 4 is built, which has a pressure medium 7 via a hydraulic line 9 to the recipient side 16 of the hydraulic coupling system 1 is transmitted. The hydraulic line 9 is adapted with respect to their length and shape of the installation space situation of the vehicle. On the taker side 16 causes the pressure P of the pressure medium 7 in a cylinder 4 ' a change of direction on a clutch 8th is transmitted to operate this. The pressure P in the cylinder 4 on the donor side 15 of the hydraulic coupling system 1 can by means of a first sensor 5 be determined. At the first sensor 5 it is preferably a pressure sensor. The of the actor 3 traveled distance along the Aktorweges is by means of a second sensor 6 determined.

In the case of a single closing / opening of the coupling, measurement data are recorded in a suitable manner, by means of which the adaptive parameters of the hydrostatic coupling system can be determined by suitable methods. This will be explained below.

Phase 1:

Determining the path-pressure characteristics when closing / opening the clutch:

For space reasons, when closing / opening the clutch a finite number (eg 20) of path-pressure-value pairs 230 . 240 saved. For example, fixed path values or path differences can be specified for determination. Similarly, the specification of fixed pressure values or pressure differences is conceivable. Because the path-pressure characteristics 210 . 220 However, have strong gradient changes, a combination of distance and pressure specification or Wegdifferenzen- and pressure difference specification is advantageous. For example, a new path-pressure value pair is saved if either the path has changed by 1 mm or the pressure has changed by 1 bar. Thus, the path-pressure characteristic curve becomes 210 . 220 by the finite number of value pairs 230 . 240 well pictured, like 2 can be seen.

The path-pressure curves are used for closing and opening 230 . 240 stored in separate data arrays.

It is advantageous, not directly the travel and pressure signals 210 to save, but easy to filter 220 (eg PT1 filter) and - following the above procedure - then the filtered values 230 . 240 save as well 2 can be seen.

Phase 2:

Evaluation of the determined path-pressure curves 230 . 240 and determination of coupling parameters:

• – Basis-Krafthysterese: Stellt eine Parallelverschiebung der Weg-Kraft-Kennlinie in Kraftrichtung in Abhängigkeit der Aktorbewegungsrichtung dar.
• – Kraft-Krafthysterese: Zusätzliche Verschiebung der Weg-Kraft-Kennlinie in Kraftrichtung in Abhängigkeit von der gegebenen Kraft. Damit kann bei höheren Kräften eine größere Hysteresebreite erzielt werden.

In addition to the adaptive parameters touch point, stiffness, form factors and leaf spring preload, further adaptive parameters must be determined. The path-force behavior in real systems depends on the actuator movement direction (open / close), the path-force characteristic therefore has a hysteresis. A simple hysteresis model results from the following two factors:

• - Basic force hysteresis: Represents a parallel displacement of the displacement-force characteristic in the direction of force as a function of the actuator movement direction.
• - Force-force hysteresis: Additional displacement of the displacement-force characteristic in the direction of force as a function of the given force. This can be achieved at higher forces a larger hysteresis width.

Instead of using forces, direct pressures can also be used in the hysteresis model. As an adaptive parameter, one thus obtains: basic pressure hysteresis, pressure-pressure hysteresis. This is in 3 shown.

Step 1: Determination of the pressure hysteresis (see FIG. 4)

The measured pressure hysteresis results from the difference between the path-pressure curves 230 . 240 for closing and opening the clutch. From the values for small actuator paths, the basic pressure hysteresis 440 . 420 be determined by averaging. From the values for medium and large actuator paths, the pressure-pressure hysteresis 430 be determined by linear approximation. The adaptive parameter of the pressure-pressure hysteresis 450 corresponds to the value at maximum actuator position (see 4 )

When driving, the current pressure hysteresis value results from the sum of the basic pressure hysteresis 420 and current pressure-pressure hysteresis 430 , In this case, the pressure-pressure hysteresis preferably increases linearly from zero at the touch point to the adaptive parameter of the pressure-pressure hysteresis at maximum actuator position.

Step 2: Determining the touch point

The determination of a clamping force characteristic 530 is carried out according to the above-mentioned German patent application DE 10 2011 081 195 - see also 5 the present document.

The determination of the clamping force characteristic 530 is according to the German patent application DE 10 2011 081 195 carried out as follows:
The path-pressure characteristic 210 in 2 shows a typical hysteresis used for the determination of the clamping force characteristic 530 is undesirable. Therefore, in a first step, the path-pressure characteristic 210 is approximated by a unique mapping such as a mean-fit approximation so that a mean pressure curve is obtained.

In the next step, the mean pressure characteristic is multiplied by the area of the slave piston 19 the clutch actuator in an engaging force FEngage 510 ( 5 ) Converted the clutch. It becomes clear that an engagement force has to be applied even in the area of small clutch positions where the clutch does not transmit any moment. This force results from spring elements - usually leaf springs - which are mounted for safe separation of clutch disc and pressure plates in the clutch. To transmit a moment on the clutch, first the clutch pressure plates must be moved towards each other against the leaf spring forces FLeafSpring, so that contact with the clutch disc takes place. Only from this point can a clamping force 530 and thus a friction torque between the clutch disc and pressure plates are constructed.

If a force sensor is used instead of a pressure sensor, the result is a similar curve as the path-force characteristic, as is the path-pressure characteristic curve 210 shows. The further procedure is analogous to the method with the path-pressure curve 210 , The path-force characteristic is thus approximated by a unique assignment, such as by the mean-fit approximation described above, so that a course analog 5 , namely the engagement force FEngage 510 the clutch as a function of the clutch position 550 results. In this way, a characteristic has 510 the engagement force FEngage of the clutch as a function of the clutch position 550 with both a pressure sensor and a force sensor. The further procedure can be identical in both cases. The force sensor used may be integrated, for example, in the clutch actuator, or located between the clutch actuator and clutch, so in particular between clutch actuator and pressure plate of the clutch are, for example, as a separate component for detecting the transmitted from the actuator to the clutch force.

The further procedure therefore consists of separating FEngage 510 in a leaf spring FLeafSpring 520 as well as the clamping force FClamp. 530 , This process is based on 5 clarified.

As long as the clutch is operated in the area of the clearance, the engagement force indicates 510 a very small gradient. This area can be defined by a straight line 520 be approximated (leaf spring force FLeafSpring 520 in 5 ).

As characteristics of the leaf spring straight lines 520 the slope and the adaptive parameter Blattfederkraftvorlast the function value of the straight line 520 at a position where the clutch is fully open and the piston 19 in the slave cylinder 4 the sniff opening 18 has crossed over in the direction of the clutch so that there is no connection of the pressure medium 7 to the expansion tank 17 consists.

After this preliminary work, the clamping force curve is obtained 530 by subtracting the leaf spring force curve 520 from the engagement force curve 510 , The result is determined by the clamping force characteristic (FClamp curve) 530 in 5 clarified.

The touch point position is now obtained by interpolation of the clamping force characteristic 530 for a given tactile force. If, on the other hand, a touch point torque-for example 5 Nm-is specified, then this must first be converted into a touch-point force.

Step 3: Determination of the preliminary form factors

First of all, the nominal clamping force characteristic stored in the control unit (standard clamping force characteristic curve for the respective coupling without adjustments) is displaced in the position direction such that the touch point corresponds to the previously determined value. For the position support points above the touch point are subsequently by interpolation of the measured, determined above clamping force characteristic 530 Force values determined. The quotients of these force values and the corresponding forces of the nominal clamping force characteristic give the provisional form factors.

Step 4: Determination of rigidity

In principle, the stiffness is the ratio of the slopes of the measured clamping force characteristic and the nominal clamping force characteristic.

This results directly as the mean of the preliminary form factors. Due to the integer arithmetic a scaling factor is optionally considered.

Step 5: Determine the final form factors

The final form factors are derived from the preliminary form factors by subtracting from them the previously calculated average. Due to the integer arithmetic a scaling factor is optionally considered.

The method is not limited to being performed only at the end of the tape. A regular implementation would also be advantageous while driving, especially before driving (but reduces the availability) or immediately after the ride (in the wake).

So proposed is a method for determining the adaptive parameters of a hydrostatic clutch system at the end of the tape by closing / opening the clutch and evaluation of the resulting pressure-displacement curve.

LIST OF REFERENCE NUMBERS

1

 Hydraulic coupling system

2

 control unit

3

 actuator

4, 4 '

 cylinder

5

 first sensor

6

 second sensor

7

 lever

8th

 clutch

9

 hydraulic line

10

 Off-pressure characteristic curve

15

 donor side

16

 recipient side

17

 surge tank

18

 sniff port

19

 piston

210

 Off-pressure characteristic curve

220

 filtered path-pressure characteristic

230

 Path-pressure value pairs: Close the clutch

240

 Path-pressure value pairs: opening the clutch

310

 Basic pressure hysteresis: closing the clutch

320

 Basic pressure hysteresis: opening the clutch

330

 Basic pressure hysteresis + pressure-pressure hysteresis: closing the clutch

340

 Basic pressure hysteresis + pressure-pressure hysteresis: opening the clutch

410

 Pressure hysteresis measured

420

 Base pressure hysteresis

430

 Pressure pressure hysteresis

440

 Adaptive parameters of the basic pressure hysteresis

450

 Adaptive parameters of the pressure-pressure hysteresis

510

 FEngage: engagement force of the clutch

520

 FLeafSpring: leaf spring force

530

 FClamp: clamping force

540

 FClutch: forces on the clutch

550

 LClutch: clutch actuator position

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010047800 A1 [0003]
• DE 102010047801 A1 [0003]
• DE 102010012756 A1 [0004]
• DE 102011081195 [0005, 0009, 0009, 0042, 0043]

Claims (13)

Method for adapting parameters of a coupling ( 8th ) of a dual-clutch transmission system which includes a hydrostatic clutch actuator ( 1 ) with a pressure sensor ( 5 ), in a motor vehicle characterized in that the following steps are carried out: - closing and / or opening the clutch ( 8th ), - detecting a pressure curve ( 210 . 220 . 230 . 240 ) by means of the pressure sensor ( 5 ) as well as the position of the coupling ( 8th ) during closing and / or opening of the coupling ( 8th ), - adaptation of the parameters for the coupling ( 8th ) from the pressure curve ( 210 . 220 . 230 . 240 ) and - using the adapted parameters in the subsequent operation of the clutch ( 8th ). A method according to claim 1, characterized in that the adaptation of the parameters during initial commissioning of the dual-clutch transmission system and / or recommissioning of the dual clutch transmission system and / or commissioning of the vehicle and / or when decommissioning of the vehicle is carried out in particular in the wake and / or during driving of the vehicle , where the parameters are "base pressure hysteresis", "pressure-pressure hysteresis", "touch point", "stiffness", "shape factors", "leaf spring force preload". A method according to claim 1 or 2, characterized in that the clutch is closed to a predetermined threshold value of the pressure and then fully driven up again and / or that the clutch is driven up to a predetermined threshold value of the pressure and then completely closed again. Method according to one of claims 1 to 3, characterized in that from the detected pressure curve, a path-pressure characteristic ( 210 . 220 . 230 . 240 ) of the clutch is determined, and that from the determined path-pressure characteristic ( 210 . 220 . 230 . 240 ) a path-engaging force characteristic ( 510 ) of the coupling is determined and that in the position range of the path-engaging force characteristic ( 510 ) in which the clutch is operated in the region of the clearance and still does not transmit any torque, an approximation with a straight line ( 520 ) having a path leaf spring force characteristic ( 520 ), wherein from the path leaf spring force characteristic ( 520 ) the parameter "leaf spring force preload" as the function value of the straight line ( 520 ) at a position at which the clutch is fully open and no torque is transmitted and the piston ( 19 ) in the slave cylinder ( 4 ) the sniffer opening ( 18 ) has crossed over in the direction of the clutch so that no connection of the pressure medium ( 7 ) to the expansion tank ( 17 ) is determined. Method according to one of claims 1 to 4, characterized in that from the detected pressure curve, a path-pressure characteristic ( 230 ) for the closing of the clutch and a path-pressure characteristic ( 240 ) for the opening of the coupling at predetermined position support points, where then path-pressure value pairs ( 230 . 240 ) and that the parameter "basic pressure hysteresis" ( 440 ) as mean value from the differences of the path-pressure characteristic ( 230 ) for the closing and the path-pressure characteristic ( 240 ) for opening at the position support points ( 230 . 240 ), which lie in a position range in which the path-pressure characteristics ( 210 . 220 . 230 . 240 ) have a gradient which is smaller than a predetermined minimum gradient threshold is determined. Method according to claim 5, characterized in that the parameter "pressure-pressure hysteresis" ( 450 ) as differences in the value of the path-pressure characteristic ( 230 ) for the closing and the value of the path-pressure characteristic ( 240 ) is determined for opening, at maximum actuator position in the direction of closing the clutch. Method according to one of claims 1 to 6, characterized in that a clamping force characteristic ( 530 ) of the coupling by subtracting the determined path leaf spring force characteristic ( 520 ) of the clutch from the determined path-engaging force characteristic of the clutch ( 510 ) is determined. Method according to one of claims 1 to 7, characterized in that the parameter "scanning point position" by interpolation of the determined clamping force characteristic ( 530 ) is determined for a given contact point force, wherein upon specification of a Tastpunktmoments a conversion takes place in a corresponding force. Method according to one of claims 1 to 8, characterized in that the clamping force characteristic ( 530 ) of the coupling is moved in the position direction such that the tactile point characterizing, predetermined position on the position axis corresponds to the determined parameter "touch point position" and being at position support points at which path-pressure value pairs ( 230 . 240 ) and above the Tastpunktposition lie in the direction of clutch close, in each case the quotient of two force values is determined, in each case one force value as an interpolation of the determined clamping force characteristic ( 530 ) and in each case the second force value is determined as an interpolation of the shifted clamping force characteristic curve and wherein the value of the quotient is in each case a parameter of the "preliminary shape factors". Method according to one of claims 1 to 9, characterized in that the parameter "stiffness" is determined as the mean value of the determined parameters of the "preliminary form factors". Method according to one of claims 1 to 10, characterized in that the parameters "final shape factors" from the parameters "preliminary shape factors" by subtracting the parameter "stiffness" are determined. Method according to one of Claims 11 or 12, characterized in that a scaling factor is additionally taken into account when determining the parameters. Method according to at least one of claims 1 to 12, characterized in that the relationship between the clamping force of the clutch and the torque transmittable by the clutch is detected by means of a torque signal during startup or in the subsequent operation of the clutch.

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