Backup system for electronic parking brake and method of providing backup power

Abstract

A back-up system (100) for an electronic parking brake (EPB) of a commercial vehicle, which ensures a safe state even in the event of a power failure of a power supply unit (50) of the EPB, the system comprising: a detection unit (110) for detecting a power failure; a storage device (120) for storing sufficient power to perform a switch to a safe state; a boost circuit (130) configured to charge the storage device (120) during vehicle standstill and to discharge the storage device (120) during vehicle movement; and a switching device (140) configured to supply power of the storage device (120) to the EPB upon detection of a power failure by the detection unit (110).

Description

Technical Field

[0001] This invention relates to a backup system for an electronic parking brake, a method for providing backup power to an electronic parking brake, and particularly to a capacitor solution for so-called gray spot adhesion. Background Technology

[0002] The parking brake of commercial vehicles utilizes a bistable pneumatic relay valve, which defines two safe positions: an inflated, unparked state and a deflated, parked state. The parking brake achieves the safe parking state through a spring chamber, allowing engagement even in the absence of power. In the unparked state, the spring chamber is inflated to release the parking brake. The second safe state is achieved through a feedback circuit that outputs control input to the relay valve.

[0003] Figure 4 A conventional electronic parking brake (or preferably its pneumatic component) for a commercial vehicle is shown, comprising a relay valve 80, an input valve 71, and an output valve 72. Furthermore, a compressed air supply 61 supplies pressurized air to the relay valve 80 and the input valve 71 via a check valve 65. The input valve 71 and the output valve 72 control the control input 81 of the relay valve 80, wherein the input valve 71 pressurizes the control input 81 when actuated, and the output valve 72 vents air. The input valve 71 and the output valve 72 are controlled by a controller (…). Figure 4 The solenoid valve is controlled by a control signal provided (not shown). The relay valve 80 is connected to the spring brake chamber at outlet 84, which is vented via exhaust end 82 (parking state) or pressurized via the pressure line of one-way valve 65 (driving state). These two states are: Figure 4 The relay valve at position 80 indicates states 1 and 4. Various pressure values ​​can be monitored by pressure sensor 76.

[0004] One safety state of the relay valve 80 is ensured by a bias spring, resulting in a default (no-pressure) position where the spring brake is depleted. A second safety state is achieved by connecting the control line of the relay valve 80 to outlet 84, inputting a pneumatic control signal to control input 81. Therefore, if outlet 84 and control input 81 remain in the same state (venting or charging), at least as long as the input and output valves 71 and 72 are in their default closed positions, even in the event of leakage.

[0005] One issue is so-called gray spot adhesion related to the intermediate position, where balancing forces may cause the piston of the relay valve 80 to remain in the intermediate position (gray spot), resulting in pressure stagnation for a period of time. Leakage will eventually determine whether the piston switches to one of the safe states. However, this phenomenon can lead to a loss of braking force after a certain period of time because the parking brake is not properly engaged. This can become a problem if the driver of a commercial vehicle has left the vehicle, as the commercial vehicle may potentially lose control without a driver.

[0006] Therefore, a safety mechanism is needed to ensure that the parking brake can be engaged in the required safe position at any time. Summary of the Invention

[0007] The system or method according to the present invention overcomes at least some of the problems of the conventional devices described above.

[0008] This invention relates to a backup system for electronic parking brakes (EPBs), particularly for EPBs in commercial vehicles, which ensures a safe state even in the event of a power failure in the EPB's power supply unit. The system includes a detection unit for detecting a power failure, a storage device for storing sufficient power to enable switching to a safe state, a boost circuit configured to charge the storage device while the vehicle is stationary and to discharge the storage device while the vehicle is in motion, and a switching device configured to supply power from the storage device to the EPB when the detection unit detects a power failure.

[0009] A stationary state can be defined as a vehicle's motion state, where the vehicle's speed is below a predetermined value of 10 km / h, 7 km / h, 5 km / h, or 3 km / h, or the speed is approximately zero.

[0010] Optionally, the EPB includes a control unit, a relay valve, and at least one solenoid valve controlled by the control unit. The at least one solenoid valve can control the pressure in the relay valve. The boost circuit can then be configured to perform one or more of the following:

[0011] - Receive control signals from the control unit indicating the vehicle's stationary and / or moving state;

[0012] - Provides a status signal indicating the charging status of the storage device to the control unit;

[0013] - Receive and / or amplify power from the power supply unit to charge the storage device (e.g., charging in less than a second).

[0014] The electrical energy stored in the storage device can be configured to actuate at least one solenoid valve. In response to the actuation of at least one solenoid valve, the actuated relay valve can respectively inflate or deflate the spring brake chamber to deactivate or activate the parking brake.

[0015] Optionally, the EPB includes a high-position switch configured to switch at least one solenoid valve. The switching device may include a backup switch and control circuitry. The backup switch may be configured to open and / or close the current path from the storage device to at least one solenoid valve. Therefore, it can serve as a backup to the high-position switch of the EPB. The control circuitry may be configured to control the backup switch, thereby controlling the power supply from the storage device to at least one solenoid valve in the event of a detected power failure.

[0016] Optionally, the EPB includes a low-position switch for switching the connection of at least one solenoid valve to ground. The control unit can be configured to control the low-position switch via a switching signal. The detection unit can be configured to control the low-position switch via a low-position switch control signal. Logic circuitry can be configured to switch the low-position switch when either the control unit provides a switching signal or the detection unit provides a low-position switch control signal.

[0017] Optionally, the detection unit is configured to provide a high-level switch control signal to the switching device to enable or trigger (e.g., in the event of a power failure) switching of the backup switch.

[0018] Optionally, the system includes a safety power supply unit configured to be charged by a storage device and / or a boost circuit, and to provide backup power to the detection unit and / or switching device.

[0019] At least one solenoid valve may be positioned between the high-level node (or high-voltage node) and ground potential. The system may optionally include at least one of the following diodes: a first diode configured to provide overvoltage protection at the high-level node; a second diode configured to prevent reverse current from the high-level node to the high-level switch; and a third diode configured to prevent current from the standby switch to the storage device. Accordingly, the diodes are arranged such that the blocking direction can prevent the corresponding current, or the breakthrough voltage can be used as the cutoff voltage to limit voltage levels exceeding ground potential (i.e., provide overvoltage protection).

[0020] Optionally, the storage device includes a capacitor located between the output of the boost circuit and ground potential.

[0021] The vehicle can be configured to supply 12 volts and / or 24 volts of power to the power supply unit. Optionally, the boost circuit is configured to amplify the voltage from the power supply unit to 50 volts. The capacitor capacitance can be in the range of 100-300 μF or approximately 220 μF.

[0022] The present invention also relates to a method for providing backup voltage to the electronic parking brake (EPB) of a commercial vehicle, so as to ensure a safe state even during a power failure in the EPB's power supply unit. The method includes:

[0023] - Detect power faults using a detection unit;

[0024] - Store sufficient power in the storage device to enable switching to a safe state;

[0025] - The storage device is charged while the vehicle is stationary via a boost circuit, and the storage device is discharged while the vehicle is in motion; and

[0026] -If the detection unit detects a power failure, it supplies power from the storage device to the EPB via a switching device.

[0027] This method, or parts thereof, can also be implemented using software or computer program products, and the order of the steps may not be important for achieving the desired effect. Therefore, the embodiments also relate to a computer program having program code that, when executed on a processor, performs the method.

[0028] The embodiments address at least some of the aforementioned problems by providing a backup power storage device, such as a capacitor, which is implemented to store sufficient energy to actuate the solenoid valve of the parking brake for a short period of time (e.g., within 50 ms to 100 ms). An exemplary capacitor can be charged or actively discharged within milliseconds, and the capacitor's state can be provided to the main controller of the parking brake system. During periods of rest, the capacitor is charged and maintains its load. When the vehicle begins to move, the movement is detected, and based on this, the capacitor is discharged to prevent any interference to the backup system while the vehicle is in motion. Attached Figure Description

[0029] The following will describe some examples of systems and / or methods by way of example and in conjunction with accompanying drawings, wherein:

[0030] Figure 1 An alternative system according to one embodiment is shown;

[0031] Figure 2 Further details of the backup system according to other embodiments are shown;

[0032] Figure 3 A schematic flowchart of a method for providing backup power according to yet another embodiment is shown;

[0033] Figure 4 The traditional electronic parking brake of a commercial vehicle is shown. Detailed Implementation

[0034] Figure 1 A backup system 100 according to one embodiment is shown. The backup system 100 is adapted to or designed for an electronic parking brake (EPB) in a commercial vehicle, the EPB including at least a power supply unit 50, a control unit 60, and at least one solenoid valve 70 configured to adjust the air pressure in the EPB according to control input from the control unit 60.

[0035] The backup system 100 is configured to ensure a safe state even during a power failure in the EPB's power supply unit 50. The backup system 100 includes a detection unit 110, a storage device 120, a boost circuit 130, and a switching device 140. The detection unit 110 is adapted to detect a power failure. The storage device 120 is adapted to store sufficient power to enable a switch to the safe state. The boost circuit 130 is adapted to charge the storage device 120 when the vehicle is stationary and to discharge the storage device 120 when the vehicle is in motion. The switching device 140 is configured to supply power from the storage device 120 to the EPB when the detection unit 110 detects a power failure.

[0036] The capacitor of storage device 120 is selected based on the energy required to activate at least one solenoid valve 70 at least once. Furthermore, storage device 120 can use one or more capacitors because they can be charged and discharged rapidly. For example, simulations show that the possible activation time of the solenoid valve is within 100 microseconds (or less), which is sufficient in practical situations.

[0037] Figure 2 Further details of a backup system 100 according to other embodiments are shown. The vehicle can be supplied with dual power, such as 12 volts and / or 24 volts, from battery 40. The parking brake includes a power supply unit 50 (PSU), a control unit 60, at least one solenoid valve 70, a high-position switch T2, and a low-position switch T1. The low-position switch T1 controls the current path from at least one solenoid valve 70 to ground potential 20, and the high-position switch T2 controls the current path between the power supply unit 50 and the solenoid valve 70. The power supply unit 50 can provide power (e.g., 5 volts) (e.g., high-voltage power) to the control unit 60 and the high-position switch T2. The power supply unit 50 may include a power converter, such as an SBC (System Base Chip), to convert exemplary battery power (e.g., 12V or 24V) into operating power (e.g., 5V). The control unit 60 is configured to control the low-position switch T1 and the high-position switch T2 to switch the solenoid valve 70.

[0038] The term "high voltage" refers to the voltage supplied by power supply unit 50 or battery compared to ground potential 20, which can be any reference potential representing "low voltage". Therefore, the term "high" refers to a significant difference from ground potential, whether it is a positive or negative voltage.

[0039] The backup system 100 is implemented in or added to a conventional EPB (represented as an existing design) and provides backup power to ensure the proper functioning of at least one solenoid valve 70. In addition to the detection unit 110, storage device 120, boost circuit 130, and switching device 140, the backup system 100 according to this embodiment also includes other components. The detection unit 110 is again configured to detect power failures from the power supply unit 50 (e.g., by monitoring the power supply battery 40). A power failure triggers the generation of corresponding control signals, such as the generation of a high-level switch control signal 135 and / or a low-level switch control signal 132.

[0040] The boost circuit 130 is configured to receive power from the power supply unit 50. This power supply may include pulse signals transmitted to the boost circuit 130, where they may be converted into sufficiently high power, such as 50 volts, to charge the storage device 120 located at the power output terminal of the boost circuit 130. The output voltage of the boost circuit 130 can be selected to ensure an ideal charging time for the storage device 120 (e.g., less than one second or less than 500 ms).

[0041] Storage device 120 may be a capacitor and is disposed between ground potential 20 and the output of boost circuit 130. Storage device 120 supplies power to switching device 140, which is configured to connect / disconnect the current path from storage device 120 to solenoid valve 70. The capacitance of exemplary capacitor 120 may be between 100 μF and 400 μF, or about 100 μF or about 220 μF. The specific value of the capacitance depends on the energy required to safely actuate at least one solenoid valve 70. For charging, a pulsed voltage can be used to ensure that exemplary capacitor 120 has a sufficiently fast charging speed.

[0042] Switching device 140 includes control circuitry 145 and a backup switch T3. Control circuitry 145 is configured to receive a high-level switch control signal 134 from detection unit 110, and in response, to switch backup switch T3 to provide backup energy from storage device 120 to solenoid valve 70, specifically to high-voltage node 75 (also referred to as a high-level node), to which high-level switch T2 is also coupled. Therefore, backup switch T3 is configured to serve as a backup for high-level switch T2. Control circuitry 145 can provide a pulse-width modulation (PWM) signal for switching backup switch T3.

[0043] The backup system 100 may further include logic circuitry 160 (e.g., an OR gate) configured to receive control signals from control unit 60 and low-level switch control signals 132 from detection unit 110 for controlling low-level switch T1. Logic circuitry 160 is configured to output control signals to low-level switch T1. Therefore, according to an embodiment, whenever logic circuitry 160 receives control signals from control unit 60 and / or detection unit 110, logic circuitry 160 is configured to output a switch signal to low-level switch T1.

[0044] The backup system 100 may also include a safety power supply unit 150, which can be charged by power from the boost circuit 130 and / or the storage device 120. The safety power supply unit 150 may be configured to provide voltage conversion so that the switching device 140 can receive an appropriate input voltage (e.g., 5 volts). Furthermore, the safety power supply unit 150 may provide a voltage supply to the detection unit 110. Therefore, even in the event of a power failure, the safety power supply unit 150 may still provide power to the control circuit 145 and / or the detection unit 110 to ensure operation, even if the main power supply unit 50 is unable to provide power. According to other embodiments, this additional power consumption is taken into account when selecting the capacitor of the storage device 120.

[0045] According to other embodiments, the backup system 100 includes at least three diodes. A first diode D1 is configured to prevent overvoltage at the high-voltage node 75 of the solenoid valve 70 and can operate in a reverse bias (blocking direction) toward ground potential 20, such that the voltage at the high-voltage node cannot exceed the break-through voltage of the first diode D1. A second diode D2 can be configured to act as a rectifier between the high-voltage node 75 and the high-level switch T2, and can, for example, block any current from the high-voltage node 75 to the high-level switch T2 and back to the power supply unit 50 in the event of a power failure. A third diode D3 can be arranged between the storage device 120 and the switching device 140, and prevents any current from the switching device 140 from flowing back to the storage device 120, but allows current to be supplied from the storage device 120 to the switching device 140.

[0046] According to other embodiments, the boost circuit 130 is controlled by the control unit 60. For example, the control unit 60 can receive a signal defining the vehicle's motion state so that it can control the boost circuit 130 to charge the storage device 120 when stationary. Furthermore, when the control unit 60 detects the vehicle's motion state (e.g., exceeding a predetermined speed of 7 km / h), it can control the boost circuit 130 to discharge the storage device 120. Finally, the boost circuit 130 can provide one or more status signals to the control unit 60 so that the control unit 60 understands the current state of the storage device 120 (whether it is charged). The information exchanged between the control unit 60 and the boost circuit 130 is via... Figure 2 The lines shown provide corresponding signals through switching.

[0047] According to other embodiments, the backup system 100 can be integrated into a printed circuit board, which may already be available and may include one or more electronic components of the EPB, such as control unit 60, power supply unit 50, low / high position switches T1, T2.

[0048] The functional operation of the backup system 100 embodiment can be described as follows. If battery depletion is detected, the parking brake solenoid valve 70 can be actuated or eventually completed using the stored energy in the storage device 120. This will result in activation or completion of actuation of the parking brake, bringing it to a safe parking state. According to the embodiment, this action will only be performed when the vehicle is stationary. In other words, when the vehicle is in motion, no energy will be stored in the energy storage device 120. If the vehicle exceeds a predetermined speed (e.g., 5 km / h or 7 km / h), it can actively discharge. If the vehicle is stationary (speed approximately zero) or below a certain speed (e.g., a predetermined speed), charging of the energy storage device 120 will proceed automatically.

[0049] This will ensure that the inflated parking brake chamber cannot be deflated or altered by external stimuli, such as specific driver or vehicle requirements, during operation.

[0050] When stationary, the preferred safe state is the safe parking state. Any intermediate position between the parking and driving states is represented by a gradually released parking brake. This embodiment avoids unnecessary intermediate positions when stationary. The backup system 100 ensures that the parking brake can always be switched to the safe parking state, even in the event of battery depletion while the vehicle is stationary.

[0051] Although the gradually releasing parking brake is a function used to prepare for starting to move the vehicle and can remain in place for several minutes until finally required to start, the embodiment ensures that the parking brake can always be reapplied in a safe state, i.e., the solenoid valve can always be actuated. This should not be a problem as long as main power is available. In the event of a power failure, the backup system 100 ensures that actuation can be performed automatically, for example, without requiring further interaction with the parking brake control unit 60, which may be unavailable during a power failure.

[0052] Figure 3 A schematic flowchart of a method for providing backup power according to other embodiments is shown. The method includes the following steps:

[0053] -Detect S110 power fault;

[0054] - Store enough power in S120 to enable switching to a safe state;

[0055] -Charging the storage device 120 S130 when the vehicle is stationary, and discharging the storage device 120 when the vehicle is in motion; and

[0056] If a power failure is detected by the detection unit 110, the power supply of the storage device 120 is supplied to the EPB via S140.

[0057] It is understandable that all the functions described with System 100 can be implemented as other optional method steps.

[0058] This method can also be implemented by a computer. Those skilled in the art will readily recognize that the steps of the various methods described above can be performed by a programmed computer. The embodiments are also intended to cover a program storage device, such as a digital data storage medium, which is machine- or computer-readable and encodes a machine-executable or computer-executable instruction program, wherein, when executed on a computer or processor, the instructions perform some or all of the actions of the methods described above.

[0059] According to other embodiments, the exemplary capacitor 120 is configured to provide a continuous power supply (e.g., during a power failure) so that no power drop occurs at the high-voltage node 75. This ensures ideal actuation of the solenoid valve 70. It is understood that the system can switch not only a single solenoid valve 70, but also multiple solenoid valves, for example... Figure 3 The input valve 71 or output valve 72 in the conventional electronic parking brake system described herein.

[0060] In summary, this embodiment provides a mechanism that is in place when a (dual) power loss in a vehicle is detected. Storage device 120 stores electrical energy, for example, in a capacitor, which can activate solenoid valve 70 if a power loss is detected, for example, in a dual power supply input. The energy or capacitance of the exemplary capacitor 120 is high enough to perform a dedicated switching of solenoid valve 70 in one of the safe states. In any case, actuation of the dedicated solenoid valve should ultimately reach one of the bistable states.

[0061] The specification and accompanying drawings are merely illustrative of the principles of this disclosure. Therefore, it is to be understood that those skilled in the art will be able to design various arrangements that, while not expressly described or shown herein, embody the principles of this disclosure and are included within its scope.

[0062] Furthermore, while each embodiment can exist independently as a separate example, it should be noted that the defined features may be combined in different ways in other embodiments; that is, a particular feature described in one embodiment may also be implemented in other embodiments. Unless it is stated that a particular combination is not intended, such combinations are included in the disclosure herein.

[0063] List of reference numerals

[0064] 20. Ground potential (reference potential)

[0065] 40. Vehicles with dual power supply (e.g., battery).

[0066] 50 Power Supply Units (PSUs)

[0067] 60 Control Unit

[0068] 61 Compressed air supply

[0069] 65 Check Valve

[0070] 70, 71, 72 At least one solenoid valve

[0071] 75 High-voltage nodes or high-level nodes

[0072] 76 Pressure Sensors (s)

[0073] 80 Relay Valve

[0074] 81 Control input of relay valve

[0075] 82 Exhaust end

[0076] 84 EPB to the spring chamber outlet

[0077] 100 Backup System

[0078] 110 Detection Unit

[0079] 120 storage device

[0080] 130 boost circuit

[0081] 132, 134 control signals

[0082] 140 Switching device

[0083] 145 Control Circuit

[0084] Switches T1, T2, and T3 (e.g., transistors)

[0085] diodes D1, D2, and D3

Claims

1. A backup system (100) for an electronic parking brake, EPB, of a commercial vehicle, which ensures a safe state even during a power failure of a power supply unit (50) of the EPB, characterized in that, The backup system comprises: - a detection unit (110) for detecting a power failure; - a storage device (120) for storing sufficient power to be able to perform a switch to a safe state; - a boost circuit (130) configured to be able to charge the storage device (120) during vehicle standstill and to discharge the storage device (120) during vehicle movement in order to prevent any disturbance to the backup system during vehicle travel; and - a switching device (140) configured to be able to supply power from the storage device (120) to the EPB in the event of a power failure detected by the detection unit (110).

2. The backup system (100) according to claim 1, wherein The EPB comprises a control unit (60), a relay valve (80) and at least one solenoid valve (70) controlled by the control unit (60), the at least one solenoid valve (70) controlling the pressure in the relay valve (80), characterized in that the boost circuit (130) is configured to be able to perform one or more of the following: - receive a control signal from the control unit (60) indicating a vehicle standstill and / or movement state; - provide a status signal to the control unit (60) indicating a charging state of the storage device (120); - receive and / or amplify power from a power supply unit (50) to charge the storage device (120) in less than one second, wherein the electrical energy stored in the storage device (120) is provided for actuation of the at least one solenoid valve (70).

3. The back-up system (100) according to claim 2, wherein The EPB further comprises a high switch (T2) configured to switch the at least one solenoid valve (70), characterized in that the switching device (140) comprises a backup switch (T3) and a control circuit (145), wherein the backup switch (T3) is configured to be able to open or close a current path from the storage device (120) to the at least one solenoid valve (70), and wherein the control circuit (145) is configured to control the backup switch (T3) so as to be able to control the power supply from the storage device (120) to the at least one solenoid valve (70) when a power failure is detected.

4. The back-up system (100) according to claim 2, wherein The EPB further comprises a low switch (T1) to switch the connection of the at least one solenoid valve (70) to ground potential (20), the control unit (60) being configured to control the low switch (T1) by a switch signal, the detection unit (110) being configured to control the low switch (T1) by a low switch control signal (132), characterized in that the backup system comprises a logic circuit (160) configured to switch the low switch (T1) when the control unit (60) provides the switch signal or the detection unit (110) provides the low switch control signal (132).

5. The back-up system (100) according to claim 3, wherein The EPB further comprises a low-position switch (T1) to switch connection of the at least one solenoid valve (70) to ground potential (20), the control unit (60) is configured to control the low-position switch (T1) by a switch signal, the detection unit (110) is configured to control the low-position switch (T1) by a low-position switch control signal (132), characterized in that the backup system comprises a logic circuit (160) configured to switch the low-position switch (T1) when the control unit (60) provides the switch signal or the detection unit (110) provides the low-position switch control signal (132).

6. Backup system (100) according to claim 3, characterized in that the detection unit (110) is configured to provide a high-position switch control signal (134) to the switching device (140) to switch the backup switch (T3) in case of a power failure.

7. Backup system (100) according to claim 5, characterized in that the detection unit (110) is configured to provide a high-position switch control signal (134) to the switching device (140) to switch the backup switch (T3) in case of a power failure.

8. Backup system (100) according to any of the preceding claims, characterized in that the backup system comprises a safety power supply unit (150) configured to be charged by the storage device (120) and / or the boost circuit (130) and to provide backup power for the detection unit (110) and / or the switching device (140).

9. The backup system (100) according to any one of claims 3, 5-7, wherein the at least one solenoid valve (70) is arranged between a high-position node (75) and ground potential (20), characterized in that the backup system comprises at least one of the following diodes (D1, D2, D3): a first diode (D1) configured to provide overvoltage protection at the high-position node (75); a second diode (D2) configured to prevent reverse current from the high-position node (75) to the high-position switch (T2); a third diode (D3) configured to prevent current from the backup switch (T3) to the storage device (120).

10. Backup system (100) according to any of claims 1-7, characterized in that the storage device (120) comprises a capacitor between an output of the boost circuit (130) and ground potential (20).

11. The system (100) of claim 10, wherein, the vehicle is configured to provide 12 volts and / or 24 volts to the power supply unit (50), characterized in that the boost circuit (130) is configured to amplify voltage from the power supply unit (50) to 50 volts; and / or the capacitor has a capacitance in the range of 100-300 pF or is 220 pF.

12. A method of providing a backup voltage for an electronic parking brake (EPB) of a commercial vehicle, which ensures a safe state even in the event of a power failure of a power supply unit (50) of the EPB, characterized in that the method comprises the following steps: - detecting (S110) a power failure by a detection unit (110); - switching (S120) the backup switch (T3) by the detection unit (110) in case of a power failure. - storing (S120) by a storage device (120) sufficient electric power to be able to perform the switching to the safe state; - charging (S130) by a boost circuit (130) the storage device (120) during vehicle standstill and discharging the storage device (120) during vehicle motion to prevent any disturbance to the backup system during vehicle travel; and - supplying (S140) by a switching device (140) electric power in the storage device (120) to the EPB if a power failure is detected by the detection unit (110).

13. A computer program having a program code, wherein, The program code causes the system according to claim 1 to perform the method according to claim 12 when the computer program is executed on a processor.

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