Method and device for a highly available automatic parking brake

Abstract

Device for an automatic parking brake, the device comprising a first microchip (101) and a second microchip (102), wherein the first microchip (101) and the second microchip (102) are configured to control a final stage (103) of the automatic parking brake, wherein the first microchip (101) and the second microchip (102) are configured redundantly with respect to controlling the final stage (103), characterized in that an interface for receiving information about the state of an operating element for the automatic parking brake is integrated into the first microchip (101) and the second microchip (102), wherein the first microchip (101) and the second microchip (102) are configured to detect a fault, and wherein the second microchip (102) is configured to control the final stage (103) depending on the information about the state of the operating element in the event of a fault, when a fault of the first microchip (101) is detected.and wherein the first microchip (101) is configured to control the final stage (103) depending on the information about the state of the control element in the event of a fault, when a fault of the second microchip (102) is detected.

Description

State of the art

[0001] The invention relates to a method and device for a highly available automatic parking brake.

[0002] An automatic parking brake is used in a vehicle to replace a manual parking brake for safely parking the vehicle. The automatic parking brake typically consists of one electric motor per wheel on the rear axle, a push button as an operating element in the vehicle interior, and a control unit (ECU). The motors engage and disengage the parking brake, with the driver usually initiating this process via the push button. In an integrated parking brake system, the control unit, such as an ESP control unit, evaluates the state of the push button and then activates the motors of the automatic parking brake.

[0003] The automatic parking brake is one of two devices suitable for parking conventional vehicles with internal combustion engines. The second device is the transmission lock (pawl) or engaging a gear in vehicles with a manual transmission.

[0004] This ensures that in the event of a failure of the ESP control unit or the automatic parking brake, a redundant parking device is available to park the vehicle safely.

[0005] DE 10 2007 029 910 A1, DE 10 2012 010 562 A1 and DE 10 2011 084 534 A1 reveal aspects of parking brakes.

[0006] German patent application DE 10 2007 029 910 A1 discloses an electric parking brake in which two redundant wheel-associated control units 2, 3 are connected via separate lines 11, 12 to a third control unit 10. The third control unit 10 detects a driver request via a button or switch to activate or deactivate the parking brake.

[0007] DE 10 2012 010 562 A1 discloses a parking brake system in which only one of the control units 12, 14 is connected to an operating device 32 which transmits signals for actuating the wheel brakes to these control units.

[0008] German patent DE 10 2011 084 534 A1 discloses a parking brake with core-redundant microcontrollers 7, 7' in a control unit 6. If the driver requests the parking brake to be applied or released via a control switch 5, the processing units 7, 7' synchronize by means of communication via an internal data bus. A command to apply or release the parking brake is exchanged during this process.

[0009] Electric vehicles do not have a conventional gearbox with a locking pawl, and therefore this parking mechanism is not available. The only means of securing the vehicle when stationary is the automatic parking brake. However, in the event of a malfunction in the ESP control unit or in the automatic parking brake's control components, this brake may no longer be activated. In this case, safely parking the vehicle is no longer possible.

[0010] An improved automatic parking brake is therefore desirable. Disclosure of the invention

[0011] This is achieved by the device and method as well as the hydraulic or electromechanical braking system according to the independent claims.

[0012] The device for an automatic parking brake comprises a first microchip and a second microchip, wherein the first and second microchips are configured to control a final stage of the automatic parking brake. The first and second microchips are redundantly configured with respect to controlling the final stage. In the event of a fault, the control capability of the automatic parking brake is thus ensured. This guarantees the safe parking of electric vehicles without a pawl, even in the event of a fault. This ensures that the parking brake functionality remains highly available and robust. Availability refers to simple electrical faults. Simple electrical faults can occur either in an ESP system, which controls the automatic parking brake under normal operating conditions, or in either of the two microchips.In case of a fault, the distributed intelligence across different circuit components makes it possible to secure the vehicle.

[0013] Preferably, the first microchip and / or the second microchip is configured as a user-defined integrated circuit (ASIC) or a field-programmable logic gate array. This allows for easy integration of redundancy into a control unit.

[0014] Preferably, the first microchip and the second microchip are arranged in the same control unit. This allows them to be located in the same control unit that, under normal operating conditions, controls the automatic parking brake.

[0015] Preferably, the first and second microchips are located in different control units. This increases availability in the event of a failure of one of the control units. This concept offers the possibility of distributing the two ASICs across two control units for high availability. Independence from the specific E / E architecture used is thus ensured.

[0016] Preferably, an interface for receiving information about the state of a control element for the automatic parking brake is integrated into the first microchip and / or the second microchip, wherein the first microchip and / or the second microchip is configured to detect a fault and to control the final stage of the automatic parking brake depending on the information about the state of the control element in the event of a fault. This enables independent fault detection, separate from the function of the control unit that controls the automatic parking brake in a fault-free state.

[0017] Preferably, the first and second microchips are configured to detect information about the movement state of a vehicle equipped with an automatic parking brake and, in the event of a fault, to activate the automatic parking brake depending on the movement state. This enables independent detection of the movement state, separate from the function of the control unit that normally activates the automatic parking brake.

[0018] Preferably, a control unit for the automatic parking brake acquires information about the vehicle's state of motion based on information about at least one wheel speed of at least one wheel of the vehicle, wherein the first microchip and / or the second microchip is configured to acquire the vehicle's state of motion based on information about at least one other wheel speed of at least another wheel of the vehicle. This allows for standstill detection even if the control unit or one of the microchips fails.

[0019] In the method for the automatic parking brake, a final stage of the automatic parking brake is controlled by a first microchip, wherein the first microchip and a second microchip are redundant to each other with respect to controlling the final stage, the second microchip controlling the final stage when a fault in the first microchip is detected.

[0020] This method offers a concept in which a microchip provides redundancy, including a security concept, through functional division and the use of the same microchip twice.

[0021] Preferably, information about the state of an operating element for the automatic parking brake is received via an interface integrated into the first and / or the second microchip, wherein the first and / or the second microchip detects the fault and controls the final stage of the automatic parking brake depending on the information about the operating element's state in the event of a fault. The state of a push button, e.g., Neutral, Apply, Release, is detected via an interface fully integrated into the microchip and thus independently of other microcontrollers or control units.

[0022] Preferably, the first microchip and / or the second microchip detects information about the movement state of a vehicle equipped with an automatic parking brake and, in the event of a fault, activates the automatic parking brake depending on the movement state. This ensures that the vehicle's standstill is detected autonomously even in the event of a fault, and the automatic parking brake remains functional.

[0023] Preferably, a control unit for the automatic parking brake acquires information about the vehicle's state of motion based on information about at least one wheel speed of at least one wheel of the vehicle, wherein the first microchip and / or the second microchip acquires the vehicle's state of motion based on information about at least one other wheel speed of at least one other wheel of the vehicle. This improves the availability of the standstill detection.

[0024] The hydraulic or electromechanical braking system in a vehicle with such a device can be used, for example, in an electric vehicle that does not have a pawl.

[0025] Further advantageous features will become apparent from the following description and the drawing. The drawing shows: Fig. 1 schematically depicts a part of a vehicle with an automatic parking brake, Fig. Two schematic steps in a procedure for an automatic parking brake.

[0026] Fig. Figure 1 schematically shows a part of a vehicle with an automatic parking brake. More precisely, it shows... Fig. 1. The design of a highly available parking brake within a control unit at the block diagram level. The highly available parking brake can also be implemented modularly, i.e., distributed across several control units.

[0027] The automatic parking brake device described below comprises a first microchip 101 and a second microchip 102. The first microchip 101 and the second microchip 102 are configured as a user-defined integrated circuit (ASIC). Alternatively, a field-programmable logic gate array can be used.

[0028] In this example, the first microchip 101 and the second microchip 102 are located in the same control unit. Alternatively, the first microchip 101 and the second microchip 102 could also be located in different control units.

[0029] The first microchip 101 and the second microchip 102 are configured to control a final stage 103 of the automatic parking brake. The first microchip 101 and the second microchip 102 are configured redundantly with respect to controlling the final stage 103.

[0030] In this example, the final stage 103 comprises a first H-bridge 104 and a second H-bridge 105.

[0031] For example, two identical ASICs are used. In this example, the control of the output stage 103 is divided into side A and side B. The first side A corresponds to the first H-bridge 104, and the second side B to the second H-bridge 105. The first microchip 101 handles the control 106 and the current and voltage measurement 107 of side A, while the second microchip 102 handles the control 108 and the current and voltage measurement 109 of side B.

[0032] The first microchip 101 has a first control line 110 and a first feedback line 111 to a power supply unit 112 for switching and reading back a main supply voltage 113 and a redundant supply voltage 114 to ensure the power supply for the output stage 103. The second microchip 102 has a second control line 115 and a second feedback line 116 to the power supply unit 112 for switching and reading back the main supply voltage 113 and the redundant supply voltage 114 to ensure the power supply for the output stage 103.

[0033] The first microchip 101 is connected to a microcontroller and a system ASIC for communication via a first bus 117, e.g., Serial Peripheral Interface (SPI). These are in Fig. Figure 1 schematically represents System 118. The second microchip 102 is connected to System 118, which comprises the microcontroller and the system ASIC, via a second bus 119, e.g., SPI, for communication purposes. The microcontroller coordinates and controls the activation of the electric parking brake in a fault-free state.

[0034] The first microchip 101 and the second microchip 102 are designed to detect information about the movement state of a vehicle in which the automatic parking brake is installed, and in case of fault, to control the automatic parking brake depending on the movement state.

[0035] The state of motion is, for example, either stationary or moving. Regardless of whether system 118, the first microchip 101, or the second microchip 102 triggers the activation of the final stage, the automatic parking brake in this example is only activated to close when stationary is detected, e.g., at a vehicle speed v < 3 km / h.

[0036] To detect the vehicle's state of motion, the control unit for the automatic parking brake in this example is configured to detect the vehicle's state of motion based on information about at least one wheel rotation speed of at least one wheel of the vehicle. The first microchip 101 and / or the second microchip 102 in this example are configured to detect the vehicle's state of motion based on information about at least one other wheel rotation speed of at least one other wheel of the vehicle.

[0037] To implement a safety concept and to detect a system 118 failure, additional signals are used. For example, signals are exchanged between system 118, the first microchip 101, and the second microchip 102 via a first signal line 120, a second signal line 121, and a third signal line 122. These signals include, for example, WAU, LS Safety Switch, and EN_EL.

[0038] A communication structure 123 between the first microchip 101 and the second microchip 102 is optionally provided to allow a possibility of releasing the automatic parking brake in the event of an emergency stop for automated parking functions.

[0039] In order to guarantee that the vehicle remains stationary even in the event of a failure of system 118 and / or either the first microchip 101 or the second microchip 102, in this example two of a total of four wheel speed sensors 124, 125, 126, 127 are read via system 118.

[0040] For example, the wheel speeds of the vehicle's front wheels are read by system 118 via a first connection 128 and a second connection 129.

[0041] For example, the wheel speeds of the rear wheels are read from the first microchip 101 via a third connection 130 and a fourth connection 131. The wheel speeds of the rear wheels are then transmitted from the first microchip 101 to the system 118 via a fifth connection 132 and a sixth connection 133.

[0042] The state of a control element 134 is read via an interface integrated into the first microchip 101 using an input line 135. An output line 136 is optionally provided, which controls a light source in the control element 134 to visually indicate to the user whether the automatic parking brake is engaged or not.

[0043] Control element 134, for example, is a button that can trigger the states Neutral, Apply, Release.

[0044] In this example, this part of the control unit is completely independent of system 118 and the second microchip 102. However, redundancy may also be provided for it.

[0045] More precisely, an interface for receiving information about the state of the control element 134 for the automatic parking brake can be integrated into the first microchip 101 and / or the second microchip 102.

[0046] The first microchip 101 and / or the second microchip 102 is also designed to detect a fault and to control the final stage 103 of the automatic parking brake depending on the information about the state of the control element 103 in the event of a fault.

[0047] In this example, the first microchip 101 is configured to detect the vehicle's standstill state and the "Apply" state of the control element 103 in the event of a fault, and to activate the first H-bridge 104 to close the automatic parking brake. Furthermore, in this example, the first microchip 101 is configured to detect a "Release" state after the brake has closed in the event of a fault, and to activate the first H-bridge to open the automatic parking brake.

[0048] A hydraulic braking system comprising this device also includes a first motor 137, which is controlled by the first H-bridge 104, to close the automatic parking brake. In this example, the hydraulic braking system includes a second motor 138, which is controlled by the second H-bridge 105, to close the automatic parking brake. These can be located at different wheels of the vehicle.

[0049] The hydraulic or electromechanical braking system is operated, for example, according to the following procedure. The steps of the procedure are in Fig. 2 schematically represented.

[0050] After startup, step 202 checks for errors. If an error occurs, step 204 is executed; otherwise, step 206 is executed.

[0051] Step 206 concerns the error-free case. The automatic parking brake is controlled by the control unit. In this example, the first microchip 101 and the second microchip 102 are controlled by system 118 to actuate the first H-bridge 104 and the second H-bridge 105.

[0052] Step 202 is then executed.

[0053] Step 204 addresses the fault situation. In step 204, the state of the control element 134 and the vehicle's movement state are checked by the first microchip 101. Depending on this, it is determined whether the automatic parking brake should be closed, opened, or left unchanged.

[0054] The state of the control element 134 for the automatic parking brake is received via the interface integrated into the first microchip 101. The first microchip 101 acquires information about the state of the control element 134, i.e., in the example, Neutral, Apply, Release.

[0055] The first microchip 101 acquires information about the vehicle's state of motion, in which the automatic parking brake is installed; that is, in this example, whether it is stationary or moving. The first microchip 101 acquires the vehicle's state of motion, which in this example is determined based on information about at least one wheel rotation speed of the vehicle's rear wheels.

[0056] Step 208 is executed if the automatic parking brake is to be released. Step 210 is executed if the automatic parking brake is to be closed. Otherwise, step 202 is executed.

[0057] In step 208, the first H-bridge 104 is controlled by the first microchip 101 to open the automatic parking brake.

[0058] Step 202 is then executed.

[0059] In step 210, the first H-bridge 104 is controlled by the first microchip 101 to close the automatic parking brake.

[0060] Step 202 is then executed.

[0061] In this example, the first microchip 101 and the second microchip 102 are configured redundantly. In case of a fault, the final stage of the automatic parking brake is controlled by the first microchip 101, provided it is functioning correctly. If it is faulty, the second microchip 102 controls the final stage when a fault in the first microchip 101 is detected. This is also checked by the second microchip 102, for example, in step 202.

[0062] This results in a highly available automatic parking brake. It is particularly advantageous if, in the technical implementation, ASICs are used that, on their own (i.e., independently), fulfill a standard function for controlling both H-bridges A and B, including current and voltage measurement according to the VDA305-100 standard, and do not inherently offer redundancy. The combination of two such ASICs, through a suitable division of functionality and the use of optional communication between the two ASICs, enables the required redundancy and intelligence to be implemented. This ensures that, in the event of a microcontroller failure in System 118, an automatic parking brake function with a corresponding safety concept is provided, including standstill detection and evaluation of the automated parking brake button press.

Claims

[1] Device for an automatic parking brake, the device comprising a first microchip (101) and a second microchip (102), wherein the first microchip (101) and the second microchip (102) are configured to control a final stage (103) of the automatic parking brake, wherein the first microchip (101) and the second microchip (102) are configured redundantly with respect to controlling the final stage (103), characterized by, that an interface for receiving information about the state of an operating element for the automatic parking brake is integrated into the first microchip (101) and the second microchip (102), wherein the first microchip (101) and the second microchip (102) are configured to detect a fault, and wherein the second microchip (102) is configured to control the output stage (103) depending on the information about the state of the operating element in the event of a fault when a fault of the first microchip (101) is detected, and wherein the first microchip (101) is configured to control the output stage (103) depending on the information about the state of the operating element in the event of a fault when a fault of the second microchip (102) is detected. [2] Device according to claim 1, characterized by, that the first microchip (101) and / or the second microchip (102) is configured as a user-specific integrated circuit or field-programmable logic gate arrangement. [3] Device according to any one of the preceding claims, characterized by , that the first microchip (101) and the second microchip (102) are located in the same control unit. [4] Device according to one of claims 1 or 2, characterized by , that the first microchip (101) and the second microchip (102) are located in different control units. [5] Device according to any one of the preceding claims, characterized by , that the first microchip (101) and the second microchip (102) are designed to acquire information about the movement state of a vehicle in which the automatic parking brake is installed, and in case of fault, to control the automatic parking brake depending on the movement state. [6] Device according to claim 5, characterized by, that a control unit for the automatic parking brake acquires information about the state of motion of the vehicle depending on information about at least one wheel speed of at least one wheel of the vehicle, and wherein the first microchip (101) and / or the second microchip (102) is configured to acquire the state of motion of the vehicle depending on information about at least one other wheel speed of at least one other wheel of the motor vehicle. [7] Method for an automatic parking brake, wherein a final stage (103) of the automatic parking brake is controlled by a first microchip (101) (208, 210), wherein the first microchip (101) and a second microchip (102) are configured redundantly with respect to controlling the final stage (103), characterized by, that the second microchip (102) controls the output stage (103) when a fault in the first microchip (101) is detected (202), wherein information about the state of a control element for the automatic parking brake is received through an interface integrated into the second microchip (102) (204), and the first microchip (101) controls the output stage (103) when a fault in the second microchip (102) is detected (202), wherein information about the state of a control element for the automatic parking brake is received through an interface integrated into the first microchip (101) (204), wherein the first microchip (101) or the second microchip detects the fault (202) and controls the output stage of the automatic parking brake depending on the information about the state of the control element in the case of a fault (208, 210). [8] Method according to one of claims 7, characterized by, that the first microchip (101) and / or the second microchip (102) receives information about a movement state of a vehicle in which the automatic parking brake is installed (204), and in case of fault, controls the automatic parking brake depending on the movement state (208, 210). [9] Method according to claim 8, characterized by , that by means of a control unit for the automatic parking brake, information about the state of motion of the vehicle is acquired depending on information about at least one wheel speed of at least one wheel of the vehicle, wherein the first microchip (101) and / or the second microchip (102) acquires the state of motion of the vehicle depending on information about at least one other wheel speed of at least one other wheel of the motor vehicle (204). [10] Hydraulic or electromechanical braking system in a vehicle with a device according to any one of claims 1 to 6.

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