DE102016203475B4 - Control device for an actuator unit of an electromechanical brake of a motor vehicle and associated operating method - Google Patents

Abstract

Method for operating a control device (4) for an actuator unit (6) of an electromechanical brake (3) of a motor vehicle (1), wherein for tensioning (15) and / or for releasing (23) the brake (3) in each case in an operating run the control device (4) the actuator unit (6) is operated electrically and during which at least one measured value (22) of at least one electrical variable (I) is recorded and depending on the at least one measured value (22) using a characteristic curve (16, 16 ') of the Actuator unit (6) a current setting state of the actuator unit (6) is determined, characterized in that - for a recognition of an actuator model (A, B) of the actuator unit (6) at least one model information (ABC) is provided and each model information (ABC) at least an actuator parameter (28) is assigned, and - in at least one test operating run by the control device (4), the actuator unit (6) is operated and the at least one measured value (22) of the at least one electrical The at least one model specification (ABC) is selected from which the associated at least one actuator parameter (28) fulfills a predetermined agreement criterion (T) with respect to the at least one recorded measured value (2), and the selected model specification (ABC) is output as the recognized actuator model (A, B).

Description

The invention relates to a method for operating a control device for an actuator unit of an electromechanical brake of a motor vehicle. The actuator unit can, for example, have an electric motor, a transmission and a conversion device by means of which a brake lining of the brake can be moved in a translatory manner. The brake can in particular be a parking brake. The invention also includes the control device for performing the method. Finally, the invention also comprises a motor vehicle which has the control device according to the invention.

Today's parking brake actuators are operated by a control device which, for example, can be integrated in a brake control device. Each parking brake actuator can be integrated in a wheel brake caliper. The control device and the actuator unit of the brake must be coordinated with one another, which is why an exchange of an actuator unit must often be accompanied by a renewed start-up.

From the DE 10 2014 222 863 A1 A control device for an electric parking brake is known which determines the current actuating state of the parking brake, for example the current position and / or contact pressure of the brake linings, on the basis of a current characteristic curve of the actuator unit of the parking brake. For a given supply voltage, the power consumption of the drive motor of the actuator unit depends on the design of the actuator unit and the mechanical resistance that the electric motor has to overcome.

One is interested in using different actuator units in the future, even if these are conceptually different, for example have different conversion devices, for example one spindle and one ball screw drive. However, this must be known in the control device in order to be able to detect its current setting state on the basis of a characteristic curve of the actuator unit. For this purpose, a corresponding control device would then have to be installed together with the actuator unit.

From the DE 10 2013 221 248 A1 a method is known by which a control device identifies an actuator using actuator-specific data. The actuator-specific data are stored on a sensor board, which is preferably spatially separated between the control unit and the actuator. The control unit receives the actuator-specific data of the actuator from the sensor board in a learning process when the control unit is paired with an actuator for the first time so that it can control the actuator in a normal operating mode.

The invention is based on the object of ensuring correct control of an actuator unit by a control device.

The object is achieved by the subjects of the independent claims. Advantageous further developments of the invention are disclosed by the features of the dependent claims, the following description and the figures.

The invention provides a method for operating a control device for an actuator unit of an electromechanical brake of a motor vehicle. The actuator unit can have an electric motor and, for example, a transmission and / or the described conversion device in order to generate a translational movement for moving a brake lining of the brake from a rotational movement of the electric motor. For tensioning and / or releasing the brake, the actuator unit is operated electrically by the control device in one operating run. So it is supplied with electrical power. For this purpose, the control device can apply a supply voltage from an electrical system of the motor vehicle to an electrical connection line for the electric motor, for example by means of an H-bridge. During operation of the actuator unit, at least one measured value of at least one electrical variable is recorded, for example the supply current which flows into the electric motor of the actuator unit. Depending on the at least one measured value, a current actuating state of the actuator unit is determined using a characteristic curve of the actuator unit. The characteristic curves describe the characteristic phases of the operational run, which are known per se, namely the start-up phase, the idle phase, the lining contact point (when closing) or the lining release phase (when releasing), the build-up of clamping force and the shutdown phase. This results in a characteristic curve and / or amount of the at least one electrical variable described by the characteristic curve. The at least one measured value thus provides information about the current control status.

In order to ensure that the actuating device operates the actuator unit with the correct actuating parameters, for example using the correct characteristic curve and / or not pulling the brake too tight and, for example, damaging the transmission, the invention provides that the control device recognizes which actuator model is actually being installed or is built in. For the recognition of the actuator model of the actuator unit, at least one model information is provided, i.e. a possible, recognizable actuator model defined, and assigned to each model specification at least one actuator parameter. In at least one test run, the control device operates the actuator unit and records the at least one measured value in the manner described. From the at least one model specification, one is then selected whose associated at least one actuator parameter fulfills a predetermined agreement criterion with regard to the at least one recorded measured value. In other words, the at least one measured value is compared with the at least one characteristic actuator value of a model specification. If the at least one measured value and the at least one actuator characteristic value are similar in the sense of the criterion of agreement, the associated model information is selected. The selected model information then corresponds to the recognized actuator model. In other words, at least one characteristic operating point is described for each actuator model in the form of the at least one actuator parameter, and the control device checks whether a suitable operating point in the sense of the match criterion is set for the built-in actuator unit in the test run. If this is the case, the corresponding model information is output as the recognized actuator model.

The invention has the advantage that the test run in the control device determines which actuator model is actually installed in the motor vehicle as an actuator unit. On the basis of the identified actuator model, a decision can then be made in an automated manner as to whether the control device is able to control the identified actuator model as intended or to operate it electrically.

The said operational run, e.g. the test operational run, provides for the opening or closing of the brake. A complete movement from a rest position of the brake linings to the locking position on the brake disc or from the locking position back to the rest position can be provided here. An operating run can also only include part of this movement.

The invention includes optional developments, the features of which result in additional advantages.

In the test run, the actuator unit runs through one or more or all of the phases described from the start-up phase to the shutdown phase. Corresponding measured values can thus be determined from one or more of these phases. For the reliable detection of an actuator model, the following actuator parameters have proven to be particularly suitable, at least one of which is provided for the detection of the actuator model: the starting current, an idle current (brake lining still without contact), a release current in the direction of releasing the brake or opening the brake, a switch-off a mutual induction (current or voltage) of the electric motor of the actuator unit when stopping or switching off.

A further development of the invention prevents the wrong actuator from inadvertently being installed in the motor vehicle, be it during manufacture or during repair or maintenance in a workshop. The further development provides that incorrect installation is signaled if no actuator model is recognized, that is to say the match criterion is not met by any model specification. In addition or as an alternative to this, incorrect installation is also signaled if the identified actuator model differs from at least one target model specification that is specified in the control device. The development prevents the motor vehicle from being driven with an incorrect actuator model.

A further development recognizes if the correct actuator model is used, but this is installed in an incorrect installation position in the motor vehicle because, for example, an actuator unit for a right side of the vehicle was installed on a left side of the vehicle. In this refinement, the control device uses the recognized actuator model to determine an intended installation position of the actuator unit and compares the intended installation position with an actual position of the actuator unit. The actual position can be identified on the basis of a connection line via which the actuator unit is electrically connected to the control device. The connection line leads to a predetermined wheel of the motor vehicle, so that the actual position of the actuator unit is determined on the basis of the connection line. If there is a difference between the intended installation position and the actual position, the control device signals that the actuator unit is installed in an incorrect installation position. This ensures that, for example, after a repair of the motor vehicle in which several actuator units have been removed, these are installed again in their intended installation position.

A further development enables the control device to adapt itself to the built-in actuator unit. In this development, the control device sets at least one predetermined control parameter for controlling the actuator unit for the identified actuator model and, in a future operating run, controls the actuator unit on the basis of the set at least one control parameter. It can That is to say, at least one parameter value can be suitably stored in a data memory for several different actuator models and the correct at least one parameter value can then be selected and set in the control parameter on the basis of the recognized actuator model.

A further development relates to the case that the actuator unit is subsequently changed, that is to say after the motor vehicle has been completed, by conversion or replacement. In this development, the aforementioned characteristic curve, on the basis of which the actuating state is recognized, or at least one measured value of at least one operating run is also used to form the at least one characteristic value for a model specification, which is referred to here as the “original actuator model”. In other words, the characteristic curve of the currently installed actuator unit is used as a source for at least one characteristic value for the model specification “original actuator model”. At a later point in time, for example after the motor vehicle has been repaired in a workshop, the at least one characteristic value is used to identify that the actuator unit has been replaced. In other words, the recognized actuator model no longer corresponds to the original actuator model. This can be because a new actuator unit has been installed or the actuator units have been installed the other way around. The control device thus independently learns the at least one characteristic value for recognizing the currently installed actuator unit.

A further development even makes it possible to have the characteristic curve of the actuator unit set automatically by the control device. In this development, the characteristic curve is selected on the basis of the recognized actuator model. Thus, for example, several characteristic curves of different actuator models can be stored in the control device and the appropriate characteristic curve can then be selected on the basis of the recognized actuator model and used for future operating runs.

A further development takes into account the fact that, due to the scattering of specimens, not every actual actuator unit has exactly the characteristic curve of the corresponding actuator model. In other words, the characteristic curve still has to be calibrated. In this refinement, provision is made for a characteristic curve that can be parameterized to be provided for the recognized actuator model. For this purpose, the characteristic curve has at least one parameter which is established by setting a corresponding parameter value. The characteristic curve can therefore be described, for example, as a mathematical assignment function that has corresponding parameters. The at least one parameter is set as a function of the at least one measured value of at least one calibration run. The characteristic curve parameterized in this way is then used as the characteristic curve of the actuator unit. This has the advantage that a characteristic curve that is individually adapted to the actuator unit is provided in the motor vehicle. A more precise or more precise conclusion about the actuating state is thus possible.

According to a further development, when checking the match criterion, an environmental property, in particular an air temperature and / or a brake temperature and / or a humidity, is also taken into account. For example, the actuator parameters of each model specification can be adapted or set as a function of the environmental properties. Corresponding dependencies of the actuator parameters on the environmental properties, e.g. temperature or humidity, can be determined through tests.

As already stated, the invention also includes the control device for the actuator unit of the electromechanical brake of the motor vehicle. The control device has a connection device for connecting a connection line for supplying the actuator unit with electrical power for an operational run. The connection device can thus for example provide electrical contacts for connecting the connection line. Furthermore, a processor device is provided which has a program code which is set up to carry out an embodiment of the method according to the invention when the program code is executed by the processor device. The processor device can for example be implemented on the basis of a microcontroller or a microprocessor. Each program code can be stored in a data memory of the processor device. The control device can in particular be designed as a brake control device for the brake.

Finally, the invention also includes a motor vehicle with at least one electromechanical brake of the type described, each brake for receiving electrical power being connected to a control device via a respective connecting line, which represents an embodiment of the control device according to the invention.

In the motor vehicle according to the invention, it is provided in particular that the at least one brake is a parking brake that holds the brake linings on a brake disc of the brake in a parking phase of the motor vehicle even in the de-energized state.

A further development provides that several brakes are provided and each brake has an actuator unit with a characteristic curve, the characteristic curves differing from one another in at least one characteristic value. In this way, the control device can use this characteristic value to differentiate between the actuator units and, for example, detect an interchange between a right and a left actuator unit, for example after a workshop repair.

The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger vehicle or truck.

• 1 eine schematische Darstellung einer Ausführungsform des erfindungsgemäßen Kraftfahrzeugs,
• 2 zwei Kennlinien von Aktuatoreinheiten unterschiedlicher Bauart oder Aktuatormodelle, wobei die Kennlinien einen Spannvorgang beschreiben, und
• 3 zwei Kennlinien der Aktuatoreinheiten für einen Lösevorgang.

An exemplary embodiment of the invention is described below. This shows:

• 1 a schematic representation of an embodiment of the motor vehicle according to the invention,
• 2 two characteristic curves of actuator units of different designs or actuator models, the characteristic curves describing a clamping process, and
• 3 two characteristics of the actuator units for a release process.

The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual features of the invention that are to be considered independently of one another, which also develop the invention independently of one another and are therefore to be regarded as part of the invention individually or in a combination other than the one shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

In the figures, functionally identical elements are each provided with the same reference symbols.

1 shows part of a motor vehicle 1 , for example a rear of the motor vehicle 1 . Wheels are shown 2 with wheel brakes or short brakes 3 and a control device 4th for the brakes 3 . The control device 4th can for example be provided by a brake control device. The control device 4th is with the brakes 3 each via an electrical connection cable 5 connected to a connection device CON the control device 4th can be connected. Via the respective connection cable 5 can be an actuator unit 6th every brake 3 with electrical energy, for example from an on-board network 7th are supplied. The electrical system 7th can be a 12-volt electrical system, for example. Through the actuator unit 6th every brake 3 can each use brake pads 8th a caliper 9 relative to a brake disc 10 the brake 3 be moved. Each actuator unit 6th for example an electric motor 11 , a transmission 12th and / or a translator 13th include. The implementation facility 13th can for example be implemented on the basis of a spindle and / or a ball screw drive. With the electric motor 11 For example, it can be a DC motor. For operating the electric motor 11 can through the control device 4th one in the connection lines 5 provided supply voltage 14th be switched. When applying the supply voltage 14th flows through the connection line 5 a supply current I. . The electric motor 11 is then in operation and moves the brake pads, for example 8th to the brake disc 10 and presses it against it, so that the brake 3 is tightened or stretched. It can be a parking brake, for example, which occurs after the electric motor has been switched off 11 the brake pads 8th continue against the brake disc 10 remain pressed and thus the vehicle rolling away 1 is prevented in a parking phase with the combustion engine switched off. To release the brake 3 can then again by means of a corresponding supply current I. the electric motor 11 by the control device 4th operated, causing the brake pads 8th from the brake disc 10 be moved away.

Due to the specific actuator concept of the actuator units 6th , that means, for example, the choice of gearbox 12th and the translator 13th , as well as due to the motor characteristics of the electric motor 11 and due to the ambient conditions, for example the temperature, when the supply voltage 40 is applied, a for the actuator unit results 6th characteristic current curve of the supply current I. . In 2 is for two different actuator models A. , B. for a clamping process for clamping 15th one characteristic each 16 shown. Each of the characteristics 16 describes the supply current I. over time t. With the brake released 3 are initially the brake pads 8th in a resting position. From there they are through the actuator unit 6th moved into a locking position or clamping position. This results in the supply current I. a starting current 17th , an idle phase 18th (during which the brake pads 8th can be moved without the brake disc 10 touching), a pad application point 19th , a build-up of tension 20th and a shutdown phase 21st .

By the control device 4th can meanwhile the supply current I. be measured so that during tensioning 15th Readings 22nd surrender. Based on the measured values 22nd can through the control device 4th based on the characteristic 16 determine how far the clamping 15th is advanced and / or whether the electric motor 11 should be switched off again. In other words, it is the current actuating state of the actuator units 6th determined. The comparison can be based on a predetermined tolerance range T be done as it is in 2 exemplary for a characteristic value 28 for the leeward phase 18th is illustrated. The tolerance range T represents a match criterion.

3 illustrates solving 23 the brake pads 8th from the brake disc 10 . This also results depending on the actuator model A. , B. another characteristic 16 ' . While loosening 23 the following phases are run through: a starting current 24 , a layer loosening phase 25th , an idle phase 26th and a shutdown phase 27 .

By the control device 4th can be based on the electrical behavior of the actuator units 6th determine which actuator model A. , B. on the wheels 3 is built in or built in. You can do this for different actuator models A. , B. , C in the control device 4th each one model information ABC and at least one assigned characteristic value 28 be provided. 2 illustrated how by four characteristic values 28 for the actuator model A. in a comparison with the measured values 22nd when clamping 15th the brakes 3 it can be seen that the actuator units 6th the actuator model A. correspond. The control device 4th can then, for example, from stored characteristics 29 the one for the actuator model A. and for operating the actuator units 6th base to determine the current control status in the manner described. For example, other control parameters can also be used 30th for the recognized actuator model A. be loaded from memory. The recognized actuator model can also be provided A. as an original actuator model or original model 31 to save to after, for example, a repair of the motor vehicle 1 to check that the actuator units 6th have been correctly installed again. Otherwise operation of the motor vehicle 1 blocked. The original actuator model 31 then also represents a target model specification.

As in 1 shown are the parking brake actuators in the brake calipers 9 integrated in the rear axle. A direct current motor is preferred as the electric motor to build up the force 11 with a multi-stage gear 12th used. Since a translational energy is necessary for the tensioning force of the brake linings, this is generated from the rotary movement by means of a spindle or crank screw drive of the conversion device 13th won. The type of conversion depends on the actuator model A. , B. .

A tension 15th The electric parking brake is activated by the electric motors 11 by the control device 4th of the brake control unit. The basic electrical variables such as voltage are used to determine the built-up clamping force 14th and electricity I. determined taking into account the actuator concept, the engine characteristics and the ambient conditions (e.g. temperature). This results in the current control status described.

In particular, the current characteristic is used to draw conclusions about the setting status (open / partially tensioned / fully tensioned). The typical characteristics 16 , 16 ' for the electricity I. for tensioning 15th and loosening 23 used.

By the control device 4th the fact that the different actuator concepts have a different influence on the characteristics is now used 16 , 16 ' and the readings 22nd to have.

As parameters 28 The following have proven particularly useful for recognizing the actuator model: the starting current 32 , the no-load current 33 , the release current 34 in the opening direction, the breaking current 35 which is characteristic due to the different degrees of efficiency of the actuator units and the mutual induction 36 . Based on these parameters 28 an actuator concept, i.e. an actuator model A. , B. , describe and distinguish it from another actuator model.

This recognition can be carried out without changing the components or hardware of the control device 4th be realized as the necessary components for determining the electrical measured values 22nd already for tensioning anyway 15th and loosening 23 Find use. Just an adaptation of a program code 37 a control device 38 is necessary to different actuator models A. , B. to recognize or a wrong installation 39 (also the swapping between left and right) to recognize and signal.

Furthermore, this method can be expanded by storing the previously performed tensioning and release characteristic curves by a comparison with a currently performed tensioning 15th and / or release 23 close. This allows, for example, incorrect installation in customer service to be identified. So it will be the original model 31 stored and a recognition carried out.

An additional expansion can be initiated by a specific calibration run. For a known or specifically set phase 17-21 , 24-27 can readings 22nd can be determined and then, for example, a parameterized characteristic 16 , 16 ' the determined measured values 22nd be adjusted.

Overall, the example shows how the invention can provide identification of a parking brake servomotor on the basis of electrical units.

List of reference symbols

1

Motor vehicle

2

wheel

3

brake

4th

Control device

5

Connecting cable

6

Actuator unit

7th

Electrical system

8th

Brake pad

9

Brake caliper

10

Brake disc

11

Electric motor

12

transmission

13

Conversion facility

14th

Supply voltage

15th

Applying the brake

16

Characteristic curve (clamping)

16 '

Characteristic curve (release)

17th

Starting current

18th

Idle phase

19th

Pad contact point

20th

Clamping force build-up

21st

Shutdown phase

22nd

Measured value

23

Release the brake

24

Starting current

25th

Base release phase

26th

Idle phase

27

Shutdown phase

28

Characteristic value

29

Saved characteristics

30th

Control parameters

31

Original actuator model

32

Starting current

33

No-load current

34

Release current

35

Shutdown current

36

Mutual induction

37

Program code

38

Processor facility

39

Incorrect installation (signal)

A.

Actuator model

ABC

Model specification

B.

Actuator model

CON

Connection device

I.

Supply current

T

Tolerance range

Claims (12)

Method for operating a control device (4) for an actuator unit (6) of an electromechanical brake (3) of a motor vehicle (1), wherein for tensioning (15) and / or for releasing (23) the brake (3) in each case in an operating run the control device (4) the actuator unit (6) is operated electrically and during which at least one measured value (22) of at least one electrical variable (I) is recorded and depending on the at least one measured value (22) using a characteristic curve (16, 16 ') of the Actuator unit (6) a current setting state of the actuator unit (6) is determined, characterized in that - for a recognition of an actuator model (A, B) of the actuator unit (6) at least one model information (ABC) is provided and each model information (ABC) at least an actuator parameter (28) is assigned, and - in at least one test run by the control device (4), the actuator unit (6) is operated and the at least one measured value (22) of the at least one el Electric variable is detected, and - from the at least one model information (ABC) one is selected whose associated at least one actuator parameter (28) meets a predetermined agreement criterion (T) with respect to the at least one recorded measured value (2), and - the selected model information (ABC) is output as the recognized actuator model (A, B). Procedure according to Claim 1 , with at least one of the following being provided as an actuator parameter (28) for each actuator model (A, B): a starting current (32), an idling current (33), a release current (34), a cut-off current (35), a counter induction ( 36) an electric motor (11) of the actuator unit (6) when stopping. Method according to one of the preceding claims, wherein incorrect installation (29) is signaled if no actuator model (A, B) is recognized, and / or at least one target model specification (31) is specified and, if this is recognized Actuator model (A, B) is different from each target model information (31), the incorrect installation (29) is signaled. Method according to one of the preceding claims, wherein the control device (4) uses the recognized actuator model (A, B) to determine an intended installation position of the actuator unit (6) and compares the intended installation position with an actual position identified using a connection line (5) and at a difference between the intended installation position and the actual position is signaled that the actuator unit (6) is installed in an incorrect installation position. Method according to one of the preceding claims, wherein at least one predetermined control parameter (30) for controlling the actuator unit (6) is set by the control device (4) for the identified actuator model (A, B) and the actuator unit (6) is activated in at least one future operating run is controlled based on the set at least one control parameter (30). Method according to one of the preceding claims, wherein the at least one actuator parameter (28) for an original actuator model (31) is formed from the characteristic curve (16, 16 ') of the currently installed actuator unit (6) or from at least one measured value (22) from an operating run and at a later point in time, based on the at least one actuator parameter (28) of the original actuator model (31), it is recognized that the actuator unit (6) has been replaced. Method according to one of the preceding claims, wherein the characteristic curve (16, 16 ') of the actuator unit (6) is selected on the basis of the identified actuator model (A, B). Method according to one of the preceding claims, wherein a characteristic curve that can be parameterized by means of at least one parameter value is provided for the recognized actuator model (A, B) and the at least one parameter value is set as a function of the at least one measured value (22) of at least one calibration operation and the parameterized characteristic is used as the characteristic (16, 16 ') of the actuator unit (6). Method according to one of the preceding claims, wherein when checking the match criterion (T), an environmental property, in particular an air temperature and / or a brake temperature and / or a humidity, is also taken into account. Control device (4) for an actuator unit (4) of an electromechanical brake (3) of a motor vehicle (1), comprising: - a connection device (CON) for connecting a connection line (5) for supplying the actuator unit (6) with electrical power for an operational run, - A processor device (38) which has program code (37) which is set up to carry out a method according to one of the preceding claims when executed by the processor device (38). Motor vehicle (1) with at least one electromechanical brake (3), each brake (3) for receiving electrical power being connected to a control device (4) via a respective connection line (5), characterized in that the control device (4) according to Claim 10 is designed. Motor vehicle (1) according to Claim 11 , wherein a plurality of brakes are provided and each brake has an actuator unit with a characteristic curve, the characteristic curves differing in at least one characteristic value.

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