DE102016206932A1 - Method of operating an automated clutch actuation system - Google Patents

Abstract

The invention relates to a method for actuating an automated clutch actuation system in which a predetermined desired clutch torque (MSoll) is output to a clutch model (3) from a higher-level controller (1) and the clutch model (3) is based on the predetermined desired clutch torque (MSoll) Clutch (5) controls and a Kupplungsistmoment (MIst) is output from the clutch model (3) to the higher-level control (1). In a method in which the desired clutch torque can be adapted to any desired driving situations, the clutch model (3) clutch-relevant relevant adapted, wherein the clutch model (3) outputs a determined due to the adaptation clutch torque correction value (MKorr) to the higher-level control (1) , Which determines the clutch desired torque (MSoll) as a function of the clutch correction value (MKorr) with a control component.

Description

The invention relates to a method for operating an automated clutch actuation system in which a predetermined desired clutch torque is output to a clutch model from a higher-level control and the clutch model controls a clutch based on the predetermined clutch desired torque and a clutch actual torque is output from the clutch model to the higher-level control.

In electronic clutch actuation systems, a clutch is described by means of a clutch model that reflects various characteristics of the clutch system. In order to obtain the most accurate coupling models, a mixture of reference properties, e.g. be determined on test benches, and in the normal driving mode adapted parameters, e.g. from the observation of engine torque and engine speed are used. By means of this clutch model, a clutch characteristic is determined, by means of which the control of the clutch is made. Such a coupling model is part of a torque interface which is assigned to a higher-level control, e.g. a driving strategy is connected. This means that the higher-level controller does not have detailed knowledge of the clutch system used in a vehicle, but only outputs a desired clutch desired torque and receives back an actual torque determined by the clutch model. If the clutch model concludes from the observation of the clutch actuation to errors in the current model, these are corrected and lead to a modified control of the clutch, which is not recognized by the higher-level control.

Particularly robust driving strategies, eg starting speed controllers, in turn calculate a desired clutch torque, for example due to a controlled setpoint speed curve. To compensate for deviations, these higher-level control systems usually have a control component, for example an integral controller, which can also compensate for errors in the clutch model. If there is an increased change in the clutch system, this leads to a compensation reaction in the clutch model as well as in the higher-level control and thus overcompensation. Such overcompensation is for example in 3 illustrated where the case is considered that after parking a vehicle, the friction properties of the clutch linings change greatly. As a result, the coefficient of friction, which is stored in the clutch model, significantly reduced, but this is not taken into account by the clutch model. From the observation of the behavior during the first approach of the vehicle after stopping, therefore, the coefficient of friction estimated by the clutch model is strongly adapted downwards, while the higher-level control attempts to regulate the engine speed by means of a greatly increased clutch torque. Since the engine and clutch torque are not identical, as can be seen from the marked point S, the adaptation of the coefficient of friction causes the actual clutch torque to increase sharply when the estimated clutch torque remains constant. As a result, the driven front wheels VL, VR unintentionally turn, because the driving strategy can not take back the over-selected clutch target torque fast enough.

The invention has for its object to provide a method for operating an automated clutch actuation system, in which the clutch desired torque can be adapted to any desired driving situation.

According to the invention the object is achieved in that the clutch model is adapted clutch torque-relevant, wherein the clutch model outputs a determined due to the adaptation clutch torque correction value to the higher-level control, which determines the clutch target torque with a rule share depending on the clutch correction value. Since the higher-level control system is informed that serious changes have taken place in the clutch actuation system that were not taken into account when determining the desired clutch torque, the higher-level controller can now take this information into account in the determination of the further clutch desired torque, thereby reducing the interaction between the clutch model and superior control can be improved.

Advantageously, the clutch torque correction value is supplied as pre-control value to the control component of the higher-level control for determining the desired clutch torque. As a result, the higher-level control is notified of the faulty behavior of the clutch model, whereby a correct desired clutch torque, which corresponds to the current clutch conditions, can be determined and the further clutch actuation can be used as a basis.

In one embodiment, the clutch torque-relevant adaptation of the clutch model is carried out after the activation of the clutch with the clutch desired value specified by the higher-level control. The clutch model notices that due to the specified desired clutch torque, the clutch assumes a different clutch actual torque than expected, after which the clutch model is adapted.

In a further development, after the clutch torque-relevant adaptation of the clutch model, the clutch torque correction value is output to the higher-level control if the actual actual clutch torque, which is set by the coupling of the clutch at the predetermined clutch setpoint, deviates from an expected actual clutch torque. Thus, the higher-level controller is simply informed about the current situation.

In one variant, the current clutch actual torque is output together with the clutch torque correction value to the higher-level controller.

Advantageously, the clutch torque correction value is determined from a difference between the expected actual clutch torque and the current actual clutch torque. Thus, the higher-level controller can cancel the target request, thereby preventing dangerous situations such as wheel spin.

The invention allows numerous embodiments. One of them will be explained in more detail with reference to the figures shown in the drawing.

Show it:

1 an embodiment of a clutch control,

2 an embodiment of the method according to the invention,

3 an embodiment of the prior art in a drive of the vehicle after a large change in the coefficient of friction.

In 1 an embodiment of a clutch control is shown which is used in the operation of an automated clutch actuation system. The automated clutch actuation system consists of a clutch torque-based-controlled driving strategy, which acts as a higher-level control 1 is formed and an interface 2 is assigned, in which a coupling model 3 is included. This interface 2 acts directly on the control electronics 4 the clutch 5 , In the higher-level control 1 is a control unit 6 , For example, an integral controller, for determining the _desired clutch torque M _target integrated. Both the parent controller 1 as well as the interface 2 are fed with the actual clutch torque M _ist and the engine speed n.

In 2 an embodiment of the method according to the invention is shown. In the block 100 gives the higher-level control 1 that through the control unit 6 specified clutch setpoint torque M _set to the interface 2 out. That in the interface 2 Discarded coupling model 3 moves the clutch 5 according to the currently available coupling model 3 to the clutch _desired torque M _target on the clutch 5 to adjust (block 110 ). If it is determined that the input of the current _desired clutch torque M _Soll results in an unexpected clutch actual torque M _ist , it is concluded that there is an error in the clutch model 3 is present. To correct this error, in step 120 an adaptation of the clutch model 3 performed by calculating the torque change generated by the adaptation to the last operating point. In step 130 the calculated torque change is referred to as clutch torque _correction value M _Korr from the interface 2 to the higher-level control 1 output (block 140 ). The higher-level control 1 used in the block 150 the received clutch _{torque correction value} M _Korr for its next calculation _step for the clutch _{target torque} M _Soll , wherein the clutch _{torque correction value} M _Korr as Vorsteuerwert in the control unit 6 is entered.

Because the coupling model 3 the clutch torque change caused by the pure adaptation of the clutch model 3 arises, the parent control 1 tells, is the driving strategy in the form of the parent control 1 able to reduce the target demand to the same extent. This not only prevents the wheels from spinning during the starting process, but also in other driving situations, for example during creeping, starting and shifting, more robustly against changes to the clutch model 3 be made. This can accelerate the adaptation and faster regulators can be implanted, as a reliable communication between coupling model 3 and higher level strategy 1 consists.

The proposed method is particularly important in clutches with ceramic-based friction linings, because they have a coefficient of friction which has a particularly pronounced dependence on, for example, the temperature and the history.

LIST OF REFERENCE NUMBERS

1

 higher-level control

2

 interface

3

 coupling model

4

 control electronics

5

 clutch

6

 control unit

M _is

 Kupplungsistmoment

M _Soll

 Clutch torque

M _corr

 Clutch torque correction value

n

 Engine speed

Claims (6)

Method for operating an automated clutch actuation system, in which a higher-level control ( 1 ) a predetermined _desired clutch torque (M _setpoint ) to a clutch model ( 3 ) and the coupling model ( 3 ) on the basis of the predetermined _desired clutch torque (M _Soll ) a clutch ( 5 ) and a Kupplungsistmoment (M _Ist ) of the coupling model ( 3 ) to the higher-level control ( 1 ), characterized in that the coupling model ( 3 ) Clutch torque-relevant adapted, wherein the clutch model ( 3 ) a determined due to the adaptation clutch _{torque correction value} (M _Korr ) to the higher-level control ( 1 ), which determines the _desired clutch torque (M _Soll ) as a function of the clutch _{correction value} (M _Korr ) with a control component. Method according to Claim 1, characterized in that the clutch _{torque correction value} (M _Korr ) as pre-control value corresponds to the control component of the higher-level control ( 1 ) for determining the _desired clutch torque (M _Soll ) is supplied. A method according to claim 1 or 2, characterized in that the clutch torque-relevant adaptation of the clutch model after the activation of the clutch ( 5 ) with that of the higher-level control ( 1 ) predetermined clutch _desired torque (M _target ) is executed. A method according to claim 3, characterized in that after the clutch torque-relevant adaptation of the clutch model ( 3 ) the clutch _{torque correction value} (M _Korr ) to the higher-level control ( 1 Is output) when the current _is Kupplungsistmoment (M), which is (due to the actuation of the clutch 5 ) with the predetermined clutch set torque (M _set ), deviates from an expected Kupplungsistmoment. Method according to at least one of the preceding claims, characterized in that to the higher-level control ( 1 ) the current clutch actual torque (M _ist ) _is output together with the clutch _{torque correction value} (M _Korr ). Method according to at least one of the preceding claims, characterized in that the clutch _{torque correction value} (M _Korr ) is determined from a difference between the expected actual clutch torque and the actual actual clutch torque (M _ist ).

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