Method for actuating an actuator of a brake system and electronic control device

Abstract

The invention relates generally to a method for actuating an actuator for a brake system, in particular a parking brake, and to an electronic control unit for actuating. The method may provide an electronic circuit assembly comprising three electrical half-bridges capable of simultaneous actuation of the two actuators in at least one series switching state by turning on a first electronic switch and simultaneously turning on a second electronic switch.

Description

Technical Field

[0001] The present invention generally relates to a method for actuating an actuator of a brake system, in particular a parking brake, and an electronic control unit for the actuation. Background Art

[0002] Modern motor vehicles often use electric parking brakes ("EPB"). These electric parking brakes can be actuated, for example, by the vehicle driver using an operating switch. It is also conceivable to realize the control, for example, by means of an onboard computer of the motor vehicle.

[0003] The electric parking brake is a complex mechatronic system and can have an electromechanical actuator for generating a parking brake force or a clamping force. These actuators can each be assigned to a wheel of the motor vehicle and ensure that the motor vehicle can be reliably immobilized.

[0004] For control purposes, corresponding electronic control units (“ECUs”) can be used, which can be connected to an operating unit or also to an onboard computer or a higher-level control unit via a corresponding data bus.

[0005] The electric parking brake, like other components of the brake system, is a safety-relevant device of a motor vehicle and must accordingly ensure functional safety.

[0006] In order to increase safety, it can be provided, for example, as described in DE 10 2011 084 534 A1 of the applicant, to use two control circuits and two independent computing units for controlling the actuators.

[0007] Current recommendations for such parking brake operation are also stored, for example, in VDA recommendations or guidelines, which can regulate, for example, the integration of the activation of the electric parking brake in the control unit. It can then be provided that the electric parking brake can be activated by the control unit, in which case both parking brake actuators can be activated independently of one another.

[0008] This can have important implications for the dynamic braking function of a vehicle with a parking brake actuator when two wheels are slip-controlled. The controller can therefore have corresponding electronic circuits, which are designed to be repeated (ie redundant) for this reason. This can be disadvantageous in many ways.

[0009] In current EPB systems, which are controlled by a controller, two EPB actuators are controlled independently of one another by means of a respective H-bridge or full bridge. The H-bridge typically comprises four transistors, which are usually designed as MOSFETs.

[0010] A disadvantage is that a total of eight such transistors or MOSFETs need to be provided. These components are relatively expensive and require additional space on the circuit board of the controller.

[0011] Therefore, a method for actuating an electric parking brake is desired which does not have the above-mentioned disadvantages or at least reduces these disadvantages.

[0012] Therefore, there is a particular desire for electronic controllers, in particular for brake systems of motor vehicles, which are cost-effective and easy to produce, but which at the same time comply with the necessary safety requirements and guidelines. Summary of the invention

[0013] The present invention achieves the above-mentioned objectives.

[0014] This object is achieved in a surprisingly simple manner by a method for the dynamic control of at least two actuators, an electronic controller, in particular for the dynamic control of at least two actuators of a brake system of a motor vehicle, and a brake system according to one of the independent claims.

[0015] Preferred embodiments and developments of the invention are apparent from the respective dependent claims.

[0016] Therefore, in a first aspect, the invention relates to a method for the dynamic control of at least two actuators for a brake system, in particular of a motor vehicle, wherein the at least two actuators are arranged such that they can be connected in series during operation when they are to rotate in opposite directions.

[0017] For the control, an electronic circuit assembly can be used which comprises three electrical half-bridges, wherein

[0018] - each half-bridge comprises a first electronic switch and a second electronic switch,

[0019] - at least one first electrical connection portion / port is provided between the first half-bridge and the second half-bridge for electrical connection with the first electrical actuator,

[0020] - a second electrical connection portion is provided between the second half bridge and the third half bridge for electrical connection with the second electric actuator,

[0021] The at least two actuators are preferably arranged such that they can be connected in series during operation when they are to rotate in opposite directions.

[0022] The method according to the present invention may comprise the following steps:

[0023] - controlling the actuator by switching on or off at least one first electronic switch and a second electronic switch to produce different switching states,

[0024] In at least one series switching state, the two actuators can be actuated simultaneously in preferably opposite directions by switching on a single first electronic switch and simultaneously switching on a single second electronic switch.

[0025] The underlying circuit assembly can therefore be designed as a B6 bridge circuit.

[0026] According to the present invention, instead of a typical two independent full H-bridge or B4-bridge system, a complete half-bridge can be omitted, and the actuators can be connected to each other and controlled via the half-bridge located therebetween.

[0027] The electronic switch can be designed as a transistor, for example as a MOSFET transistor, which can be advantageous for applications in motor vehicles. MOSFETs are commonly used in the automotive industry due to their high power density, fast switching speed and high efficiency. In addition, they are smaller and lighter than bipolar transistors, for example.

[0028] Here, the method also provides a possible way to adjust the direction of the current through the actuator. The method according to the invention has the advantage that only six electronic switches have to be provided instead of eight electronic switches as would otherwise be the case. As a result, the method has cost advantages and at the same time saves space on the circuit board of the controller.

[0029] The actuator can be controlled by switching the first electronic switch and / or the second electronic switch on or off in order to produce different connection or switching states.

[0030] For the circuit assembly according to the invention, the actuators can be arranged according to a particularly preferred embodiment of the invention such that: when they are to rotate in opposite directions, they are connected in series or can be connected in series. This connection is also referred to as a series switching state within the scope of the invention.

[0031] This connection or this series switching state can be achieved by switching on a first electronic switch and simultaneously switching on a second electronic switch.

[0032] Preferably, the first electronic switch can belong to the first half bridge or the third half bridge and the second electronic switch can belong to the third half bridge or the first half bridge in order to establish a series connection. The remaining electronic switches, in particular the electronic switches belonging to the second half bridge, can be switched off or open.

[0033] In this case, the faster actuator can determine the reference current intensity by sensing the reverse voltage. On the other hand, due to the circuit structure, the state of one actuator will also affect the other actuator.

[0034] This is of importance, for example, when the actuators are to be braked. If, for example, two actuators are to rotate in the closing direction (i.e., not energized in series) and, for example, one of the actuators is to be stopped, this can be achieved by closing the open second electrical switch of the circuit assembly and simultaneously opening the closed first electrical switch. In this case, the actuator is short-circuited.

[0035] The control of the circuit assembly is therefore more complex than in the case of two B4 bridge circuits. It is advantageous to always take into account the switching state of each electrical switch. Compared with individual control via two B4 bridges, the redundancy of the circuit assembly and the method is lower, but this is acceptable for certain applications.

[0036] The method according to the invention can be used, for example, in emergency situations where a motor vehicle needs to be braked while maintaining stability. In this case, the performance of the method according to the invention is almost the same as two B4 bridge circuits.

[0037] According to a further development of the invention, the rotational speed or velocity of the actuator can be controlled by pulse width modulation (e.g. of the voltage). For this purpose, a further first electronic switch and a further second electronic switch can be switched on and acted upon by means of pulse width modulation. Controlling the actuator by means of pulse width modulation is considered to be known to the person skilled in the art and does not need to be described in further detail here. The actuator can be optimally adjusted by implementing pulse width modulation by means of the intermediate half bridge.

[0038] In this case, the respective further first electronic switch and the further second electronic switch can belong to the same half-bridge in which no electronic switch is switched. In the case of the series switching state, the respective further first electronic switch and the further second electronic switch can belong to the middle second half-bridge.

[0039] The circuit assembly can preferably be operated with direct current so that the actuator can be operated in two opposite directions. Preferably, the actuator is correspondingly designed to be operable with direct current. For this purpose, the first electronic switch can be electrically connected to a connection terminal for applying a supply voltage.

[0040] In the series switching state, the at least two actuators can be simultaneously operated in opposite directions. To this end, the polarization directions of the first electrical connection portion and the second electrical connection portion can be opposite.

[0041] According to a particularly preferred embodiment of the invention, the electronic circuit assembly can have exactly three electrical half-bridges, wherein each of these half-bridges can have a corresponding control circuit. The control circuit can be connected in a known manner to a microcontroller, which can include a corresponding control algorithm for control.

[0042] In another aspect, the invention also comprises an electronic control unit for dynamically controlling at least two actuators in pairs. The actuators can belong to a parking brake of a brake system of a motor vehicle, for example.

[0043] However, actuators designed in other ways are also possible and conceivable, provided that they are driven and actuated in pairs. This may also be, for example, an actuator for a window lifter in a motor vehicle.

[0044] To this end, the electronic controller according to the invention can have an electronic circuit assembly comprising three electrical half-bridges,

[0045] in

[0046] - each half-bridge comprises a first electronic switch and a second electronic switch,

[0047] - at least one first electrical connection is provided between the first half-bridge and the second half-bridge for electrical connection to the first electrical actuator, and

[0048] - a second electrical connection portion is provided between the second half bridge and the third half bridge for electrical connection with the second electric actuator,

[0049] The at least two actuators are preferably arranged such that they can be connected in series during operation when they are to rotate in opposite directions.

[0050] According to a preferred embodiment of the present invention, the at least two actuators which can be controlled in pairs can each include a DC motor which can be driven in two directions.

[0051] In yet another aspect, the present invention also comprises a braking system for a motor vehicle, the braking system comprising an electronic controller as described above.

[0052] The brake system may include at least two wheel brakes, which are preferably arranged opposite each other and each have at least one actuator which can be controlled in pairs by an electronic control unit.

[0053] According to a preferred embodiment of the present invention, the wheel brake can be designed as a parking brake.

[0054] Further details of the invention emerge from the description of the illustrated embodiments and from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In the attached figure:

[0056] Figure 1 A diagram showing a circuit arrangement according to the invention for dynamically controlling at least two actuators,

[0057] Figure 2 A truth table showing the switching states. DETAILED DESCRIPTION

[0058] In the following detailed description of the preferred embodiments, for the sake of clarity, the same reference numerals represent substantially the same components in or on these embodiments. However, in order to better illustrate the present invention, the preferred embodiments shown in the drawings are not shown to scale.

[0059] The invention relates to a method for dynamically controlling at least two actuators 30.1, 30.2 of a braking system, in particular of a motor vehicle, wherein

[0060] - for control purposes, an electronic circuit assembly 10 is used, which comprises three electrical half-bridges 20.1, 20.2, 20.3;

[0061] - Each half bridge 20.1, 20.2, 20.3 comprises a first electronic switch H20.1, H20.2, H20.3 and a second electronic switch L20.1, L20.2, L20.3;

[0062] - at least one first electrical connection 14 is provided between the first half-bridge 20.1 and the second half-bridge 20.2 for electrical connection to the first electrical actuator 30.1,

[0063] - a second electrical connection 15 is provided between the second half bridge 20.2 and the third half bridge 20.3 for electrical connection to the second electric actuator 30.2,

[0064] The at least two actuators 30.1, 30.2 are preferably arranged such that they can be connected in series during operation when they are to rotate in opposite directions.

[0065] The method according to the present invention proposes the following steps:

[0066] - controlling the actuators 30.1, 30.2 by switching on or off at least one first electronic switch H20.1, H20.2, H20.3 and a second electronic switch L20.1, L20.2, L20.3 to produce different switching states,

[0067] In at least one series switching state, the two actuators 30.1, 30.2 can be simultaneously actuated in preferably opposite directions by switching on a first electronic switch H20.1, H20.2, H20.3 and simultaneously switching on a second electronic switch L20.1, L20.2, L20.3.

[0068] The circuit assembly 10 suitable for use in the present invention is Figure 1 As shown in the example, the circuit arrangement is designed as a B6 bridge circuit.

[0069] The method provides the possibility of adjusting the direction of the current through the actuator 30.1, 30.2 by switching the electronic switches H20.1, H20.2, H20.3, L20.1, L20.2, L20.3 on or off. Different connection or switching states can be generated.

[0070] The method according to the invention offers the advantage that only six electronic switches H20.1, H20.2, H20.3, L20.1, L20.2, L20.3 have to be provided instead of eight electronic switches as would otherwise be the case.

[0071] The electronic switches H20.1, H20.2, H20.3, L20.1, L20.2, L20.3 are designed as transistors. In the present embodiment, the electronic switches H20.1, H20.2, H20.3, L20.1, L20.2, L20.3 are designed as MOSFET transistors.

[0072] In the circuit assembly 10 , the actuators 30 . 1 , 30 . 2 are arranged such that they are connected in series or can be connected in series when they are to rotate in opposite directions.

[0073] This series switching state of the actuators 30.1 and 30.2 can be achieved by switching on a first electronic switch H20.1, H20.2, H20.3 of the circuit assembly 10 and simultaneously switching on a second electronic switch L20.1, L20.2, L20.3 of the circuit assembly. In this regard, the first electronic switches H20.1, H20.2, H20.3 are high-side switches of the circuit assembly 10 and the second electronic switches L20.1, L20.2, L20.3 are low-side switches. In other words, the series switching state of the actuators 30.1 and 30.2 can be achieved by switching on a high-side switch and a low-side switch and simultaneously switching off the remaining electronic switches of the circuit assembly 10.

[0074] The series switching state according to the invention can be established in the following case, that is, in the circuit assembly 10, the first electronic switch H20.1 of the first half bridge 20.1 and the second electronic switch of the other half bridge 20.3 or the first electronic switch H20.3 of the third half bridge 20.3 and the second electronic switch L20.1 of the first half bridge 20.1 are connected, wherein the remaining electronic switches are turned off. During operation, the current then flows along the nodes K1, K2 and K3 in the first case or flows in the opposite direction through K3, K2 and K1 in the second case. Therefore, the electronic switches H20.2 and L20.2 of the second half bridge 20.2 connected to the node K2 can be disconnected.

[0075] In another switching state of the circuit assembly 10, the two actuators 30.1, 30.2 rotate in the same direction, for example. This can be achieved in the circuit assembly 10 by, for example, switching on the electronic switches H20.1, H20.3 and L20.2 and switching off the remaining electronic switches H20.2, L20.1 and L20.3.

[0076] If now, for example, Figure 1 The actuator 30.2 indicated on the right is stopped, which can be achieved by switching on or closing the electronic switch L20.3 and switching off or opening the electronic switch H20.3 belonging to this half bridge 20.3. Thus, the actuator 30.2 is short-circuited via the low-side switches L20.1, L20.2, L20.3.

[0077] According to a further development of the invention, the rotational speed or velocity of the actuators 30.1, 30.2 can be controlled by means of pulse width modulation. For this purpose, a further first electronic switch and a further second electronic switch can be switched on and acted upon by means of pulse width modulation. In this case, these are the switches H20.2 and L20.2 of the middle half bridge 20.2.

[0078] The circuit assembly 10 is operated with direct current so that the actuators 30.1, 30.2 can be operated in a predetermined direction or in two opposite directions. The actuators 30.1, 30.2 are designed accordingly. For this purpose, the high-side switches H20.1, H20.2, H20.3 are electrically connected to the connection terminal 13 for applying a supply voltage.

[0079] In the series switching state, the at least two actuators 30.1 and 30.2 can be simultaneously operated in opposite directions. To this end, the polarization directions of the first electrical connection 13 and the second electrical connection 14 are opposite.

[0080] The electronic circuit assembly 10 has exactly three electrical half-bridges 20.1, 20.2, 20.3, wherein each of these half-bridges 20.1, 20.2, 20.3 has a corresponding control circuit 11 to open (off) or close (on) the switch. The control circuit 11 is connected to a microcontroller (not shown) which includes a corresponding control algorithm and a computer program for the control.

[0081] The invention also relates to an electronic control unit for dynamically controlling at least two actuators 30.1, 30.2 in pairs. The actuators 30.1, 30.2 can be, for example, parking brakes of a brake system of a motor vehicle.

[0082] To this end, the electronic controller according to the invention can have an electronic circuit assembly 10 which comprises three electrical half-bridges 20.1, 20.2, 20.3, wherein

[0083] - Each half-bridge 20.1, 20.2, 20.3 comprises a first electronic switch or high-side switch H20.1, H20.2, H20.3 and a second electronic switch or low-side switch L20.1, L20.2, L20.3;

[0084] - at least one first electrical connection 14 is provided between the first and second half-bridges 20.1, 20.2 for electrical connection to the first electrical actuator 30.1,

[0085] - a second electrical connection 15 is provided between the second and third half bridges 20.2, 20.3 for electrical connection to the second electric actuator 30.2,

[0086] The at least two actuators 30.1, 30.2 are preferably arranged such that they can be connected in series during operation when they are to rotate in opposite directions.

[0087] The electronic control unit according to the invention is also designed to carry out the method as described above.

[0088] The at least two actuators which can be controlled in pairs each include a direct current motor which can be driven in two opposite directions.

[0089] In the exemplary embodiment depicted, the actuators 30 . 1 , 30 . 2 belong to the parking brake or parking brake of a braking system of a motor vehicle.

[0090] In yet another aspect, the present invention also comprises a braking system for a motor vehicle, the braking system comprising an electronic controller as described above.

[0091] The brake system comprises at least two wheel brakes, which are preferably arranged opposite each other and each have at least one actuator which can be controlled in pairs by an electronic control unit.

[0092] The wheel brakes are designed here as parking brakes or parking brakes.

[0093] Figure 2 1 shows a truth table for different selected switching states of the circuit assembly 10. The different switching states can be set by correspondingly switching on or off the first electronic switch or high-side switch H20.1, H20.2, H20.3 and the second electronic switch or low-side switch L20.1, L20.2, L20.3. Figure 2 The switching state is shown in the truth table using "EIN" for "on"; when the switch is off, no entry is stored in the truth table.

[0094] As can be seen from the table, the two actuators 30.1, 30.2 can be driven either individually or together. If the actuators are to be driven together, this can be done in opposite directions or in opposite directions of rotation (thus in the closing direction and the opening direction) or in the same direction of rotation.

[0095] When using pulse width modulation ( Figure 2 When controlling the two actuators 30.1 and 30.2 by means of pulse width modulation (“PWM” in FIG. 1 ), it should be noted that the two actuators 30.1 and 30.2 are acted upon by means of pulse width modulation.

[0096] Reference numerals list:

[0097] 10 Circuit Components

[0098] 11 Control lines

[0099] 13. Connecting terminals

[0100] 14 Connection

[0101] 15 Connection

[0102] 20.1 Half Bridge

[0103] 20.2 Half Bridge

[0104] 20.3 Half Bridge

[0105] 30.1 Actuator

[0106] 30.2 Actuator

[0107] H20.1 Switch

[0108] H20.2 Switch

[0109] H20.3 Switch

[0110] L20.1 Switch

[0111] L20.2 Switch

[0112] L20.3 Switch

[0113] K1 Node

[0114] K2 Node

[0115] K3 Node

Claims

1. A method for dynamically controlling at least two actuators (30.1, 30.2) of a braking system, in particular of a motor vehicle, wherein - for control purposes, an electronic circuit assembly (10) is used, which comprises three electrical half-bridges (20.1, 20.2, 20.3); - Each half-bridge (20.1, 20.2, 20.3) comprises a first electronic switch (H20.1, H20.2, H20.3) and a second electronic switch (L20.1, L20.2, L20.3); - at least one first electrical connection portion (14) is provided between the first half-bridge (20.1) and the second half-bridge (20.2) for electrical connection to a first electrical actuator (30.1), - a second electrical connection portion (15) is provided between the second half bridge (20.2) and the third half bridge (20.3) for electrical connection with the second electrical actuator (30.2), - the at least two actuators (30.1, 30.2) are preferably arranged such that they can be connected in series during operation when they are to rotate in opposite directions, - The method comprises the following steps: - controlling the actuator (30.1, 30.2) by switching on or off at least one first electronic switch and a second electronic switch (H20.1, H20.2, H20.3, L20.1, L20.2, L20.3) to produce different switching states, Wherein in at least one series switching state, By switching on a first electronic switch (H20.1, H20.2, H20.3) and simultaneously switching on a second electronic switch (L20.1, L20.2, L20.3), the two actuators (30.1, 30.2) can be actuated simultaneously, preferably in opposite directions.

2. The dynamic control method according to the preceding claim, characterized in that In the series switching state, the first electronic switch (H20.1, H20.3) belongs to the first half bridge (20.1) or the third half bridge (20.3), and the second electronic switch (L20.1, L20.3) belongs to the third half bridge (20.3) or the first half bridge (20.1).

3. The dynamic control method according to one of the preceding claims, characterized in that In the series switching state, the remaining electronic switches (H20.1, H20.2, H20.3, L20.1, L20.2, L20.3), in particular the electronic switches of the second half bridge (20.2), are turned off.

4. The dynamic control method according to one of the preceding claims, characterized in that A further first electronic switch (H20.1, H20.2, H20.3) and a further second electronic switch (L20.1, L20.2, L20.3) can be switched on and pulse width modulation can be applied to them.

5. The dynamic control method according to one of the preceding claims, characterized in that The circuit assembly (10) operates with direct current.

6. The dynamic control method according to one of the preceding claims, characterized in that In the series switching state, the at least two actuators (30.1, 30.2) can be simultaneously operated in reverse.

7. The dynamic control method according to one of the preceding claims, characterized in that The electronic circuit assembly (10) comprises exactly three electrical half-bridges (20.1, 20.2, 20.3).

8. The dynamic control method according to one of the preceding claims, characterized in that The first electronic switches (H20.1, H20.2, H20.3) are each electrically connected to a connection terminal (13) for applying a supply voltage.

9. The dynamic control method according to one of the preceding claims, characterized in that The polarization directions of the first electrical connection portion (14) and the second electrical connection portion (15) are opposite.

10. An electronic control unit for dynamically controlling at least two actuators (30.1, 30.2) of a braking system, in particular of a motor vehicle, the electronic control unit preferably being designed to carry out the method according to one of the preceding claims, - the electronic controller has an electronic circuit assembly (10) comprising three electrical half-bridges (20.1, 20.2, 20.3), in - Each half-bridge (20.1, 20.2, 20.3) comprises a first electronic switch (H20.1, H20.2, H20.3) and a second electronic switch (L20.1, L20.2, L20.3); - at least one first electrical connection portion (14) is provided between the first half-bridge (20.1) and the second half-bridge (20.2) for electrical connection to a first electrical actuator (30.1), - a second electrical connection portion (15) is provided between the second half bridge (20.2) and the third half bridge (20.3) for electrical connection with the second electrical actuator (30.2), The at least two actuators (30.1, 30.2) are preferably arranged such that they can be connected in series during operation when they are to rotate in opposite directions.

11. Electronic controller according to the preceding claim, characterized in that The at least two actuators (30.1, 30.2) each include a DC motor that can be driven in two directions.

12. Electronic controller according to one of the two preceding claims, characterized in that The at least two actuators (30.1, 30.2) belong to a parking brake of a brake system of a motor vehicle.

13. A braking system, in particular a braking system of a motor vehicle, comprising an electronic controller according to one of the preceding claims 10 to 12.

14. Braking system according to the preceding claim, characterized in that The brake system comprises at least two wheel brakes which are preferably arranged opposite each other and each of which has at least one actuator (30.1, 30.2).

15. Braking system according to one of the two preceding claims, characterized in that The wheel brakes are designed as parking brakes or parking brakes.

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