Control device and control method

Abstract

A controller (10) provided in a vehicle having an electric braking device (40), a first power supply system (20) and a second power supply system (30) configured to supply power to the electric braking device (40), and a relay (70) provided between the electric braking device (40) and the second power supply system (30), the controller (10) comprising: a malfunction detection unit (11) configured to detect a malfunction in the first power supply system (20); a power supply system control unit (12) configured to control a power supply to the electric brake device (40) based on a detection result of the malfunction detection unit (11), wherein the power supply system control unit (12) is configured to: Obtaining a speed of the vehicle; closing the relay (70) in a case when an execution of an automatic parking function of the vehicle starts; During the execution of the automatic parking function, causing the first power supply system (20) to supply power to the electric braking device (40) without causing the second power supply system (30) to supply power to the electric braking device (40) by setting a target output voltage of the second power supply system (30) to a first voltage when the malfunction detection unit (11) does not detect a malfunction in the first power supply system (20), the first voltage being lower than an output voltage of the first power supply system (20); Causing the second power supply system (30) to supply power to the electric braking device (40) during the execution of the automatic parking function by setting the target output voltage of the second power supply system (30) to a voltage within a range in which the electric braking device (40) is operable when the malfunction detection unit (11) detects the malfunction in the first power supply system (20); and During execution of the automatic parking function, causing the second power supply system (30) to supply power to the electric braking device (40) by setting the target output voltage of the second power supply system (30) to be higher than the first voltage when the first power supply system (20) does not malfunction and the speed of the vehicle becomes lower than a predetermined speed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The invention relates to a control device and a control method for an electric braking device of a vehicle. 2. Description of the state of the art

[0002] A vehicle with an automatic parking function for automatically performing parking is equipped with an electric brake device that receives an instruction from an in-vehicle device that controls the automatic parking function, instead of receiving a brake pedal operation from a user, and operates a brake. A technology is known in which two systems of a main power supply system and an auxiliary power supply system are provided as the power supply system, which supply power to the electric brake device. When the main power supply system malfunctions, the vehicle is braked and stopped by forcibly operating the electric brake device through the auxiliary power supply system.

[0003] For example, Japanese Unexamined Patent Application Publication JP 2015-160591 A discloses an electric braking device equipped with a power generation device that converts a part of kinetic energy generated during running of a vehicle into electric energy and charges an auxiliary power supply device therewith, which is capable of driving an electric motor using the auxiliary power supply device when the power in the main power supply device does not reach a set reference.

[0004] In addition, Japanese Unexamined Patent Application Publication JP 2004 - 322 987 A discloses a power supply device for an electric brake, which is equipped with a main battery and an auxiliary power supply device consisting of a capacitor, and supplies power from the auxiliary power supply device to the brake when an abnormality is detected in which a voltage of the main battery is lower than a reference value.

[0005] Furthermore, JP 2019-30116 A shows a power supply system comprising a first and a second battery having a lower voltage than the first battery, a DC-DC converter, an electronic device connected to the first battery via a first wiring and connected to a primary side of the DC-DC converter via a second wiring, a first relay connecting the first wiring and the second wiring, and a second relay inserted between the second battery and the secondary side of the DC-DC converter.Furthermore, DE 11 2017 003 661 T5 discloses an emergency power supply unit of an emergency power device, wherein, when it is determined that a battery failure has been detected in the battery failure determination process, a switching command determination process is provided for determining, based on a command signal from a monitoring circuit, whether or not a command to switch to a P range has been given by a user, and when it is determined in the switching command determination process that a switching command has been given, a switching command process is provided for starting power supply from an emergency power source to a switching control unit and instructing the switching control unit to switch to the P range. SUMMARY OF THE INVENTION

[0006] In JP 2015-160951 A and JP 2004-322987 A, the auxiliary power supply system is electrically connected to the electric brake device after a malfunction is detected in the main power supply system. Such electrical connection is generally performed using a relay or the like. However, because operation of the relay or the like requires a predetermined time, there is a possibility that a time delay occurs from the time a malfunction is detected in the main power supply system to the time power supply is started by the auxiliary power supply system, and a temporary power supply failure may occur. If the temporary power supply failure occurs during execution of automatic parking, the brake may not operate during the failure, so it is not possible to brake the vehicle immediately.

[0007] It is an object of the present invention to provide a control device and a control method for an electric brake device that can quickly brake and stop a vehicle by using an auxiliary power supply system even when a main power supply system malfunctions.

[0008] The object is achieved according to the invention by a control system according to claim 1 and a control method according to claim 8. Further features and advantageous developments are shown in the subclaims.

[0009] A first aspect of the present invention is a controller provided in a vehicle, including an electric braking device, a first power supply system and a second power supply system configured to supply electric power to the electric braking device, and a relay provided between the electric braking device and the second power supply system. The controller includes a malfunction detection unit configured to detect a malfunction in the first power supply system, and a power supply system control unit configured to control power supply to the electric braking device based on a detection result of the malfunction detection unit. The power supply system control unit is configured to: obtain a speed of the vehicle;Closing the relay in a case when execution of an automatic parking function of a vehicle starts; causing, during execution of the automatic parking function, the first power supply system to supply power to the electric braking device without causing the second power supply system to supply power to the electric braking device by setting a target output voltage of the second power supply system to a first voltage lower than an output voltage of the first power supply system when the malfunction detection unit does not detect a malfunction in the first power supply system;and causing the second power supply system to supply power to the electric braking device during the execution of the automatic parking function by setting the target output voltage of the second power supply system to a voltage within a range in which the electric braking device is operable when the malfunction detection unit detects the malfunction in the first power supply system; and causing the second power supply system to supply power to the electric braking device during the execution of the automatic parking function by setting the target output voltage of the second power supply system to be higher than the first voltage when the first power supply system is not malfunctioning and the speed of the vehicle becomes lower than a predetermined speed;

[0010] In the first aspect, the second power supply system may include a capacitor as a power source. The power supply system control unit may perform a process of discharging the capacitor after an ignition is turned off.

[0011] In the first aspect, the power supply system control unit may obtain a voltage of the capacitor, and terminate the discharging process when the voltage of the capacitor becomes lower than a predetermined lower limit voltage through the discharging process.

[0012] In the first aspect, the malfunction detection unit may obtain the output voltage of the first power supply system, and detect the malfunction in the first power supply system when the output voltage of the first power supply system is less than or equal to a predetermined malfunction detection voltage.

[0013] In the first aspect, the malfunction detection unit may detect the malfunction in the first power supply system when a state in which the output voltage of the first power supply system is less than or equal to a predetermined malfunction detection voltage continues for a predetermined time.

[0014] In the first aspect, the target output voltage of the second power supply system may be determined based on a voltage of the capacitor. In the first aspect, the predetermined speed may be set such that a certain energy storage amount of the capacitor is ensured even when power supply from the second power supply system to the electric brake device is started, and then, when the first power supply system malfunctions, the output voltage of the second power supply system is maintained at an operating voltage of the electric brake device until the vehicle is stopped.

[0015] A second aspect of the present invention is a control method of controlling a vehicle having an electric braking device, a first power supply system, and a second power supply system configured to supply power to the electric braking device, and a relay provided between the electric braking device and the second power supply system. The control method includes a step of detecting a malfunction in the first power supply system, a step of closing the relay when execution of an automatic parking function of the vehicle starts, a step of obtaining a speed of the vehicle, and a step of causing the first power supply system to supply power to the electric braking device during execution of the automatic parking function without causing the second power supply system.supplying power to the electric braking device by setting a target output voltage of the second power supply system to a first voltage that is lower than an output voltage of the first power supply system when the malfunction in the first power supply system is not detected, and a step of causing the second power supply system to supply power to the electric braking device by setting the target output voltage of the second power supply system to a voltage within a range in which the electric braking device is operable when the malfunction in the first power supply system is detected; and causing the second power supply system (30) to supply power to the electric braking device (40) during the execution of the automatic parking function,by setting the target output voltage of the second power supply system (30) to be higher than the first voltage when the first power supply system (20) does not malfunction and the speed of the vehicle becomes lower than a predetermined speed.,

[0016] According to each aspect of the present invention, it is possible to provide a control of an electric brake device that eliminates a time delay caused by a relay operation for connecting a second power supply system, which is an auxiliary power supply system, when a first power supply system, which is a main power supply system, malfunctions, thereby quickly braking and stopping a vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which like reference numerals designate like elements, and in which: Fig. 1 is a diagram showing a schematic configuration of a control device and its peripherals according to an embodiment of the present invention; Fig. 2 is a flowchart of control performed by the control device according to an embodiment of the present invention; Fig. 3 is a diagram describing control by the control device according to an embodiment of the present invention; Fig. 4 is another diagram describing control by the control device according to an embodiment of the present invention; Fig. 5 is yet another diagram describing control by the control device according to an embodiment of the present invention; and Fig. 6 is yet another diagram describing control by the control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF EMBODIMENTS

[0018] According to an embodiment of the present invention, it is possible to supply power from a first power supply system (a main power supply system) and a second power supply system (an auxiliary power supply system) to an electric braking device. The electric braking device and the second power supply system are connected to each other via a relay prior to the start of execution of an automatic parking function. During execution of the automatic parking function, when the first power supply system is not malfunctioning, a target output voltage of the second power supply system is set low, so that power is supplied only from the first power supply system and not from the second power supply system.During the execution of the automatic parking function, when the first power supply system malfunctions, the target output voltage of the second power supply system is set to a voltage at which the electric braking device can operate, and the vehicle is stopped by operation of the electric braking device. As such, it is possible to remove a time delay caused by a relay operation for connecting the electric braking device to the second power supply system when the first power supply system malfunctions, thereby quickly braking and stopping the vehicle, as compared to when the relay operation is performed after the first power supply system malfunctions.

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Example configuration

[0020] Fig. 1 is a diagram illustrating a schematic configuration of a vehicle-mounted control device 10 and the periphery of the control device 10 according to an embodiment of the present invention. Each configuration will be explained with reference to Fig. 1. The type of vehicle is not specifically limited, and examples include a gasoline vehicle, a hybrid vehicle (HV), and an electric vehicle (EV). Fig. 1, a power line is represented by a solid line, and a control signal line is represented by a dashed line. Electric braking device

[0021] An electric braking device 40 brakes the vehicle based on an instruction from an automatic parking control device 100, which will be described below. The electric braking device 40 includes an actuator and a control unit that controls the actuator according to the instruction from the automatic parking control device 100. The electric braking device 40 can receive power from a first power supply system 20 and a second power supply system 30, which will be described later. The type of the electric braking device 40 is not limited as long as it is a braking system (a brake-by-wire) that can be actuated by an electric control signal from a vehicle-mounted device, such as the automatic parking control device 100. For example, the actuator can be an electric pump, a valve, or the like.that controls hydraulic pressure based on a control signal in a hydraulic brake. Alternatively, the actuator may be a motor that controls hydraulic pressure based on the control signal in the electric brake controller, which can variably control the application distribution between a regenerative brake and the hydraulic brake, instead of a booster device. Alternatively, the actuator may be an electric device that generates driving force based on the control signal in a direct-drive brake, which electrically generates the driving force of a friction element, such as a force for pressing a disc brake pad against a brake rotor (or a force for pressing a drum brake shoe against a brake drum), and directly transmits the driving force to the friction element without using hydraulic pressure. First energy supply system

[0022] The first power supply system 20 is a main power supply system that supplies power to the electric braking device 40. The first power supply system 20 includes, for example, a first battery 21, a second battery 23, and a first DC-DC converter (a first DDC) 22 provided between them.

[0023] The first battery 21 may be, for example, a lithium-ion battery charged with power supplied from outside the vehicle or power generated by a generator provided in the vehicle. The second battery 23 may be, for example, a lead-acid storage battery with an output voltage lower than that of the first battery 21. The first DCDC converter 22 converts the output of the first battery 21 to a predetermined voltage. The output of the first DCDC converter 22 and the output of the second battery 23 become the output of the first power supply system 20. The output of the first DCDC converter 22 is also used to charge the second battery 23.The first power supply system 20 may supply power to the control device 10, the automatic parking control device 100, or the like, and may also supply power to one or more devices such as a light (a load 90). Second energy supply system

[0024] The second power supply system 30 includes a second DCDC converter (a second DDC) 31, a capacitor 32 connected to the second large DCDC converter 31, and a first relay 33. The first relay 33 is installed to be able to form a discharge path for the capacitor 32 by short-circuiting terminals of the capacitor 32 in a closed state. The capacitor 32 is a power source of the second power supply system 30.

[0025] The second DCDC converter 31 can perform bidirectional voltage conversion output. Specifically, the second DCDC converter 31 converts the output of the capacitor 32 to a target output voltage, which will be described below, and makes it the output of the second power supply system 30. In addition, the second DCDC converter 31 converts the output of the first power supply system 20, which is supplied through a second relay 80, which will be described below, to a predetermined voltage and supplies it to the capacitor 32, thereby charging the capacitor 32.

[0026] A first rectifier element (diode) 50 is installed between the first power supply system 20 and the electric braking device 40. The first rectifier element 50 has one end connected to the first power supply system 20 as an input side, and the other end connected to the electric braking device 40 as an output side.

[0027] A third relay 70 and a second rectifier element (diode) 60 are installed in series between the second power supply system 30 and the electric braking device 40. The second rectifier element 60 has one end connected to the second power supply system 30 as an input side, and the other end connected to the electric braking device 40 as an output side.

[0028] The second relay 80 is installed between the first power supply system 20 and the second power supply system 30.

[0029] The output sides of the first rectifier element 50 and the second rectifier element 60 are connected to each other and have the same potential. The above output sides can be connected outside the electric braking device 40, as illustrated, or can be connected inside the electric braking device 40. Control device

[0030] The control device 10 controls a power supply from the second power supply system 30 to the electric brake device 40. The control device 10 includes a malfunction detection unit 11 and a power supply system control unit 12. The control device 10 is typically an electronic control unit (ECU) including a processor, a memory, an input / output interface, and the like.

[0031] The malfunction detection unit 11 detects whether a malfunction occurs in the first power supply system 20. Although a method for detecting a malfunction by the malfunction detection unit 11 is not particularly limited, in the present embodiment, for example, the malfunction detection unit 11 detects a malfunction based on the output voltage of the first power supply system 20 measured by a voltage sensor (not shown).

[0032] The power supply system control unit 12 may acquire information indicating an execution state of an automatic parking function from the automatic parking control device 100, a detection result of a malfunction in the first power supply system 20 from the malfunction detection unit 11, and a measurement result of a voltage (a storage amount of energy) of the capacitor 32. Furthermore, the power supply system control unit 12 may appropriately acquire information indicating a power supply state of an ignition (on / off) or information indicating various operating states of the vehicle, such as the vehicle speed, from various devices provided in the vehicle.The power supply system control unit 12 controls the first relay 33, the second relay 80, and the third relay 70, and sets a target output voltage of the second power supply system 30 by controlling the second DCDC converter 31 of the second power supply system 30 based on the above-described conditions, the detection result of the malfunction in the first power supply system 20 obtained from the malfunction detection unit 11, and the like, thereby controlling the power supply to the electric brake device 40. Control device for automatic parking

[0033] The automatic parking control device 100 is installed in a vehicle to implement the automatic parking function. Upon receiving a parking instruction from a user, the automatic parking control device 100 controls the vehicle by generating an instruction to control the driving force, braking force, steering angle, and the like of the vehicle based on, for example, information about the vehicle and its surroundings measured by various sensors provided in the vehicle, and outputting the instruction to an engine or motor control device, an electric brake device 40, a longitudinal control device, and the like provided in the vehicle, so that the vehicle can be automatically parked in a parking space.

[0034] Furthermore, the type of automatic parking function realized by the automatic parking control device 100 is not limited. Examples of the type of automatic parking function include parking in the parking space according to an instruction from a user sitting in a driver's seat in the vicinity of the parking space, remote parking in the parking space according to an instruction from the user who has exited the vehicle in the vicinity of the parking space, and automatic parking service in which the vehicle is moved from an entrance of a parking space to the parking space and moved into the parking space according to an instruction from the user who has exited the vehicle at the entrance of the parking space. steering

[0035] The control of the power supply system performed by the control device 10 during the execution of the automatic parking function will be further described with reference to the drawings. Fig. 2 is a flowchart illustrating a flow of control processing performed by the control device 10. The Fig. 3 to 6 are diagrams describing electrical connection states between the first power supply system 20, the second power supply system 30, and the electric braking device 40. In the Fig. 3 to 6, connection paths defined by the states of the first relay 33, the second relay 80 and the third relay 70 are represented by thick hatched lines. Fig. The control illustrated in Fig. 2 is an example of control that starts from the execution of the automatic parking function by the automatic parking control device 100 according to an instruction from a user.

[0036] Fig. 3 illustrates a connection state before the start of execution of the automatic parking function in an ignition-on state of the vehicle. In a state before the start of execution of the automatic parking function, the power supply system control unit 12 of the control device 10 opens the third relay 70, and the output of the second power supply system 30 is not connected to the electric brake device 40. Therefore, the electric brake device 40 is supplied with power only from the first power supply system 20. In addition, the power supply system control unit 12 of the control device 10 charges the capacitor 32 with the output of the first power supply system 20 by opening the first relay 33 and closing the second relay 80.

[0037] A process performed by the control device 10 when the automatic parking function is performed will be described with reference to Fig. 2 described.

[0038] Step S101: When information indicating that the execution of the automatic parking function has been started is acquired from the automatic parking control device 100, the power supply system control unit 12 closes the third relay 70 and opens the second relay 80.

[0039] Through the above process, not only the first power supply system 20 but also the second power supply system 30 can supply power to the electric brake device 40, as shown in Fig. 4 is illustrated.

[0040] Step S102: The power supply system control unit 12 limits power supply from the second power supply system 30 to the electric braking device 40 by controlling the target output voltage of the second power supply system 30 when there is no malfunction of the first power supply system 20. In the present embodiment, the power supply system control unit 12 limits power supply from the second power supply system 30 to the electric braking device 40 by setting the target output voltage of the second power supply system 30 to a first voltage V b1 , which is lower than an output voltage of the first power supply system 20 when it is not malfunctioning, and does not apply a forward bias voltage to the second rectifier element 60. For example, the first voltage V b1lower than a current measured value obtained by monitoring the output voltage when the first power supply system 20 is not malfunctioning. Alternatively, the first voltage V b1 be set lower than an assumed range of the output voltage when the first power supply system 20 is not malfunctioning. However, the first voltage V b1 not be too low, and should, for example, be higher than a predetermined malfunction detection voltage V d , which will be described below. As such, when the first power supply system 20 malfunctions, power can be quickly supplied from the second power supply system 30 to the electric braking device 40. This process can be performed before step S101.

[0041] Step S103: The malfunction detection unit 11 detects whether a malfunction exists in the first power supply system 20. If a malfunction is detected in the first power supply system 20 (Yes in step S103), the process proceeds to S104. If no malfunction is detected (No in step S103), the process proceeds to step S106.

[0042] The malfunction detection unit 11 can detect the malfunction in the first power supply system 20 by acquiring the output voltage of the first power supply system 20 and detecting the facts that the acquired output voltage is less than or equal to the malfunction detection voltage V d The malfunction detection voltage V d is set, for example, lower than an assumed range of the output voltage when the first power supply system 20 does not malfunction.

[0043] Alternatively, in order to detect a malfunction more accurately, the malfunction detecting unit 11 may detect the malfunction when a state in which the output voltage of the first power supply system 20 is less than or equal to the predetermined malfunction detecting voltage V d lasts for a predetermined period of time.

[0044] Step S104: When the detection result indicating that the malfunction is detected is detected by the malfunction detection unit 11, the power supply system control unit 12 sets the target output voltage of the second power supply system 30 to an operating voltage of the electric brake V f. In particular, the target output voltage is set by issuing an instruction corresponding to the target output voltage to the second DCDC converter 31. As such, power can actually be supplied from the second power supply system 30 to the electric braking device 40, as shown in Fig. 5. The time period from when the instruction to set the target output voltage is issued until the output voltage of the second power supply system 30 actually follows the instruction is generally shorter than the time period required to open and close the relay. The operating voltage of the electric brake V fis a voltage within a range in which the electric brake device 40 can stop the vehicle, and may be a fixed value or a variable value as long as it is within this range. Furthermore, the power supply system control unit 12 brakes the vehicle by operating the electric brake device 40. In addition, as described above, when the first voltage V b1 , which is the output voltage of the second power supply system 30, is set higher than the malfunction detection voltage V d in step S102, compared to when the first voltage V b1 less than or equal to the malfunction detection voltage V d would be set, it is possible to set in this step the required time period of when the target output voltage of the second power supply system 30 is set to the operating voltage of the electric brake V fis set until the output voltage actually reaches the operating voltage of the electric brake V f reached, to shorten.

[0045] Step S105: The power system control unit 12 obtains information such as the vehicle's speed and determines whether the vehicle can stop. If the vehicle can stop (Yes in step S105), the process proceeds to step S110. Otherwise (No in step S105), step S105 is repeated until it is confirmed that the vehicle has stopped.

[0046] Step S106: The power system control unit 12 obtains the vehicle speed and determines whether the vehicle speed is lower than a predetermined speed SPD, which will be described below. If the vehicle speed is lower than the speed SPD (Yes in step S106), the process proceeds to step S107. Otherwise (No in step S106), the process returns to step S103.

[0047] Step S107: The power supply system control unit 12 controls the second power supply system 30 so that power is supplied from the second power supply system 30 to the electric brake device 40 even if the first power supply system 20 does not malfunction, by increasing the target output voltage of the second power supply system 30. For example, the power supply system control unit 12 sets the target output voltage of the second power supply system 30 to a second voltage V b2, which is determined based on the output voltage of the first power supply system 20 and the voltage drop amount of the first rectifying element 50 and the second rectifying element 60, and which is greater than or equal to a voltage that applies the forward bias voltage to the second rectifying element 60. As such, power is supplied to the electric braking device 40 from both the first power supply system 20 and the second power supply system 30, or only from the second power supply system 30. As described above, near the end of parking, after the speed of the vehicle becomes lower than the speed SPD by the operation of the electric braking device 40, power is supplied from the second power supply system 30 to the electric braking device 40.Therefore, the energy stored in the capacitor 32 can be effectively utilized, and deterioration of the vehicle's fuel efficiency can be limited. The speed SPD is set so that a certain amount of energy storage of the capacitor 32 can be ensured even when power is started from the second power supply system 30 to the electric brake device 40, and subsequently, when the first power supply system 20 malfunctions, the output voltage of the second power supply system 30 can be reliably maintained at the operating voltage of the electric brake V. f can be maintained until the vehicle is stopped.

[0048] Step S108: The power system control unit 12 may obtain information indicating that the execution of the automatic parking function has ended from the automatic parking control device 100 and determine whether the execution of the automatic parking function has ended. If the execution of the automatic parking function has ended (Yes in step S108), the process proceeds to step S109. Otherwise (No in step S108), the process returns to process S103.

[0049] Step S109: The control device 10 obtains information indicating the power supply state of the vehicle and determines whether the ignition has been turned off. If the ignition has been turned off (Yes in step S109), the process proceeds to step S110. Otherwise (No in step S109), step S109 is repeated until ignition off is confirmed. In addition, the ignition is turned off according to, for example, an instruction from the automatic parking control device 100 or a user after the execution of the automatic parking function is terminated.

[0050] Step S110: The power supply system control unit 12 starts discharging the capacitor 32 by opening the third relay 70 and closing the first relay 33, as shown in Fig.6. Moreover, in this process, although the power supply system control unit 12 does not need to open the third relay 70, by opening the third relay 70, it is possible to reliably restrict an unexpected influence on the electric brake device 40 or the first power supply system 20.

[0051] Step S111: The power supply system control unit 12 obtains the voltage of the capacitor 32, and determines whether the voltage has become lower than a predetermined lower limit voltage V e . When the voltage of the capacitor 32 becomes lower than the lower limit voltage V e (Yes in step S111), the process is terminated. Otherwise (No in step S111), step S110 is repeated. The lower limit voltage V eis set to a voltage at which the capacitor 32 does not deteriorate even if it is not used for a long time. As such, it is possible to limit deterioration or wear of the capacitor 32. Furthermore, it is possible to prevent the power supply system control unit 12 from remaining in standby for a long time until the capacitor 32 is completely discharged. The power supply system control unit 12 can acquire the voltage of the capacitor 32 before the process of step S110, and terminate the process without performing steps S110 and S111 if the acquired voltage is lower than the lower limit voltage V eFurthermore, the second power supply system 30 may be equipped with another power supply source, such as a secondary battery, instead of the capacitor 32. In this case, if the power supply source does not deteriorate even without being discharged, the discharge process in steps S110 and S111 may be omitted. Beneficial effect

[0052] As described above, the control device 10 according to an embodiment of the present invention closes the third relay 70 prior to starting the autonomous parking function, so that the second power supply system 30 is electrically connected to the electric braking device 40. This makes it possible to eliminate a time delay caused by switching the state of the relay, which is required when the second power supply system 30 is electrically connected to the electric braking device 40 via the relay, or the like after the first power supply system 20 malfunctions. Therefore, even if the first power supply system 20 malfunctions, the vehicle can be quickly braked and stopped by the second power supply system 30.

[0053] Furthermore, the target output voltage of the second power supply system 30 in a state where the first power supply system 20 is not malfunctioning is set lower than the output voltage of the first power supply system 20 in a state where the first power supply system 20 is not malfunctioning. As such, the power in the second power supply system 30 is not supplied to the electric brake device 40, and therefore, it is possible to maintain the energy storage amount of the second power supply system 30 in preparation for the occurrence of a malfunction in the first power supply system 20.

[0054] In addition, when the speed of the vehicle becomes lower than the predetermined speed SPD, the target output voltage of the second power supply system 30 is reduced to a predetermined second voltage V b2 set to be greater than or equal to the malfunction detection voltage V dAt this time, near the end of parking, after the vehicle speed becomes lower than the SPD speed, through the operation of the electric limit device 40, power is supplied from the second power supply system 30 to the electric brake device 40. Therefore, the energy charged in the capacitor 32 can be effectively utilized, and deterioration of the vehicle's fuel efficiency can be prevented.

[0055] Additionally, depending on the type of automatic parking, the vehicle may be braked multiple times for reverse steering or the like. In this case, for example, the control device 10 may acquire information indicating a control state of the electric brake device 40 from the automatic parking control device 100 in step S106. Then, the process may proceed to step S107 only if the acquired information indicates that the electric brake device 40 is being actuated with respect to the last stop in the automatic parking and the vehicle speed is lower than the speed SPD. Otherwise, the process may return to step S103.

[0056] At this time, during braking other than braking with respect to the last stop, it is possible to maintain the energy storage amount of the capacitor 32 in preparation for occurrence of a malfunction in the first power supply system 20 without supplying power from the second power supply system 30 to the electric brake device 40. Modified examples

[0057] In steps S106 and S107 of the above-described embodiment, although the target output voltage of the second power supply system 30 is changed based on the vehicle speed, the target output voltage of the second power supply system 30 may be changed based on the voltage of the capacitor 32 in addition to the vehicle speed. For example, when the voltage of the capacitor 32 is relatively high and the energy storage amount thereof is large, the target output voltage of the second power supply system 30 is set relatively high, so that the power supply from the second power supply system 30 becomes large. Thereby, the energy charged in the capacitor 32 can be used more efficiently.Furthermore, when the voltage of the capacitor 32 is relatively low and the energy storage amount thereof is small, the target output voltage of the second power supply system 30 is set relatively low, so that the power supply from the second power supply system 30 becomes small. Thereby, the energy storage amount in the capacitor 32 can be more reliably maintained in preparation for the occurrence of a malfunction in the first power supply system 20.

[0058] Furthermore, in step S104, for example, the control device 10 may store or acquire a map by determining the speed of the vehicle at the time when the first power supply system 20 malfunctions and the corresponding operating voltage of the electric brake V f are recorded, and the power supply system control unit 12 can control the operating voltage of the electric brake V fAdjust according to the speed with reference to the map.

[0059] The present invention can be applied to a power supply control device of an electric brake device of a vehicle or the like.

[0060] A controller (10) comprises a malfunction detection unit (11) that detects a malfunction in a first power supply system (20), and a power supply system control unit (12) that closes a relay (70) in a case when execution of an automatic parking function starts, and during the execution of the function, causes the first power supply system (20) to supply power to the electric braking device (40) without causing a second power supply system (30) to supply power thereto, by setting a target output voltage of the second power supply system (30) to be lower than an output voltage of the first power supply system (20) when the malfunction detection unit (11) does not detect the malfunction, and the electric braking device (40) by setting the target output voltage to a voltage within a range in which the electric braking device (40) is operable,actuated when the malfunction detection unit (11) detects the malfunction.,

Claims

[1] A controller (10) provided in a vehicle having an electric braking device (40), a first power supply system (20) and a second power supply system (30) configured to supply power to the electric braking device (40), and a relay (70) provided between the electric braking device (40) and the second power supply system (30), the controller (10) comprising: a malfunction detection unit (11) configured to detect a malfunction in the first power supply system (20); a power supply system control unit (12) configured to control a power supply to the electric brake device (40) based on a detection result of the malfunction detection unit (11), wherein the power supply system control unit (12) is configured to: Obtaining a speed of the vehicle; closing the relay (70) in a case when an execution of an automatic parking function of the vehicle starts; During the execution of the automatic parking function, causing the first power supply system (20) to supply power to the electric braking device (40) without causing the second power supply system (30) to supply power to the electric braking device (40) by setting a target output voltage of the second power supply system (30) to a first voltage when the malfunction detection unit (11) does not detect a malfunction in the first power supply system (20), the first voltage being lower than an output voltage of the first power supply system (20); Causing the second power supply system (30) to supply power to the electric braking device (40) during the execution of the automatic parking function by setting the target output voltage of the second power supply system (30) to a voltage within a range in which the electric braking device (40) is operable when the malfunction detection unit (11) detects the malfunction in the first power supply system (20); and During execution of the automatic parking function, causing the second power supply system (30) to supply power to the electric braking device (40) by setting the target output voltage of the second power supply system (30) to be higher than the first voltage when the first power supply system (20) does not malfunction and the speed of the vehicle becomes lower than a predetermined speed. [2] Controller (10) according to claim 1, wherein: the second power supply system (30) comprises a capacitor as a power source, the power supply system control unit (12) is configured to perform a process of discharging the capacitor after an ignition is turned off. [3] Controller (10) according to claim 2, wherein the power system control unit (12) is configured to: Obtaining a voltage from the capacitor; Terminating the discharging process when the voltage of the capacitor becomes lower than a predetermined lower limit voltage due to the discharging process. [4] Controller (10) according to one of claims 1 to 3, wherein the malfunction detection unit (11) is configured to: Obtaining the output voltage of the first power supply system (20); Detecting the malfunction in the first power supply system (20) when the output voltage of the first power supply system (20) is less than or equal to a predetermined malfunction detection voltage. [5] Controller (10) according to one of claims 1 to 3, wherein the malfunction detection unit (11) is configured to: Obtaining the output voltage of the first power supply system (20); Detecting the malfunction in the first power supply system (20) when a state in which the output voltage in the first power supply system (20) is less than or equal to a predetermined malfunction detection voltage continues for a predetermined time. [6] Controller (10) according to claim 1, wherein: the second power supply system (30) comprises a capacitor as a power source; and the target output voltage of the second power supply system (30) is determined based on a voltage of a capacitor. [7] Controller (10) according to claim 1, wherein: the second power supply system (30) comprises a capacitor as a power source; and the predetermined speed is set such that a certain energy storage amount of the capacitor is ensured even when the power supply from the second power supply system (30) to the electric braking device (40) is started, and then, when the first power supply system (20) malfunctions, the output voltage of the second power supply system (30) is maintained at an operating voltage of the electric braking device (40) until the vehicle is stopped. [8] A control method for controlling a vehicle having an electric braking device (40), a first power supply system (20) and a second power supply system (30) configured to supply power to the electric braking device, and a relay (70) provided between the electric braking device (40) and the second power supply system (30), the control method comprising: Detecting a malfunction in the first power supply system (20); closing the relay (70) in a case when an execution of an automatic parking function of the vehicle starts; Obtaining a speed of the vehicle; Causing, during execution of the automatic parking function, the first power supply system (20) to supply power to the electric braking device (40) without causing the second power supply system (30) to supply power to the electric braking device (40), by setting a target output voltage of the second power supply system (30) to a first voltage when the malfunction is not detected in the first power supply system (20), the first voltage being lower than an output voltage of a first power supply system (20); Causing the second power supply system (30) to supply power to the electric braking device (40) during the execution of the automatic parking function by setting the target output voltage of the second power supply system (30) to a voltage within a range in which the electric braking device (40) is operable when the malfunction is detected in the first power supply system (20); and During execution of the automatic parking function, causing the second power supply system (30) to supply power to the electric braking device (40) by setting the target output voltage of the second power supply system (30) to be higher than the first voltage when the first power supply system (20) does not malfunction and the speed of the vehicle becomes lower than a predetermined speed.

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