Brake system

Abstract

To be able to suppress deterioration in braking force when electric power supply from either of a first power source and a second power source is stopped.SOLUTION: A brake system is provided with a plurality of master controllers 50A and 50B, and a plurality of slave controllers 60A-60D. Electric power is supplied from a first power source 11 to the master controller 50A, the slave controller 60B and the slave controller 60C. Electric power is supplied from a second power source 12 to the master controller 50B, the slave controller 60A and the slave controller 60D. The master controller 50A and the slave controller 60A can control an electric brake 20A, the master controller 50B and the slave controller 60B can control an electric brake 20B, the slave controller 60C can control an electric brake 20C, and the slave controller 60D can control an electric brake 20D.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a braking system applied to a vehicle.

Background Art

[0002] Patent Document 1 discloses an example of an in-vehicle system including a vehicle motion integrated control ECU and four BBW driver ECUs. When the vehicle brakes, the vehicle motion integrated control ECU calculates an instruction value for the braking force to be generated on a plurality of wheels. The vehicle motion integrated control ECU outputs the calculated instruction value to the plurality of BBW driver ECUs. The BBW driver ECU adjusts the braking force generated on the corresponding wheel by controlling an electric motor based on the input instruction value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When two power sources are provided in a vehicle, it is possible that the first power source among the two power sources supplies power to a part of the four BBW driver ECUs, and the second power source supplies power to the rest of the four BBW driver ECUs. An object of the present invention is to suppress a decrease in the braking force of a vehicle when power supply from one of the two power sources is stopped in a braking system capable of receiving power supply from the two power sources.

Means for Solving the Problems

[0005] A brake system for solving the above problems is a system applicable to a vehicle equipped with a first power source and a second power source separate from the first power source. The brake system comprises a plurality of master controllers including a first to fourth electric actuator that generates braking force on each of the first to fourth wheels of the vehicle, a driver that adjusts the power supplied to any one of the first to fourth electric actuators, a braking force calculation unit that calculates the braking force generated on the first to fourth wheels by the driving of the first to fourth electric actuators, and a driver control unit that operates the driver according to the calculation result of the braking force calculation unit, and a plurality of slave controllers including a driver that adjusts the power supplied to any one of the first to fourth electric actuators, and a driver control unit that operates the driver according to the calculation result of the braking force calculation unit of the master controller. The first master controller among the plurality of master controllers, and the first slave controller and the second slave controller among the plurality of slave controllers, constitute a first controller group that is not supplied with power from the second power source but is supplied with power from the first power source. The second master controller among the plurality of master controllers, and the third and fourth slave controllers among the plurality of slave controllers, constitute a second controller group that is not supplied with power from the first power supply but is supplied with power from the second power supply. The first defining controller among the first controller group and the second defining controller among the second controller group both control the first electric actuator. The third defining controller among the first controller group, which is different from the first defining controller, and the fourth defining controller among the second controller group, which is different from the second defining controller, both control the second electric actuator. One controller among the first controller group, which is different from the first defining controller and the third defining controller, controls the third electric actuator.Of the second group of controllers, one controller different from the second defining controller and the fourth defining controller controls the fourth electric actuator.

[0006] In the above braking system, even if power supply from the first power source is cut off, if power is supplied from the second power source, the multiple controllers constituting the second controller group can operate using power supplied from the second power source. Therefore, braking force can be generated on three of the four wheels. Conversely, even if power supply from the second power source is cut off, if power is supplied from the first power source, the multiple controllers constituting the first controller group can operate using power supplied from the first power source. Therefore, braking force can be generated on three of the four wheels.

[0007] Therefore, the above-described braking system can suppress the reduction in braking force when power supply from either the first power source or the second power source is stopped. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing a vehicle to which the brake system of this embodiment is applied. [Figure 2] Figure 2 is a block diagram showing the configuration of the brake system. [Figure 3] Figure 3 is a table showing the relationship between the master controller, which calculates the instructed braking force to be used when the braking control device of the brake system can be operated normally, and the operating driver. [Figure 4] Figure 4 is a table showing the relationship between the master controller, which calculates the instructed braking force to be used, and the operating driver when power supply from either the first or second power supply is stopped. [Figure 5] Figure 5 is a table showing the relationship between the master controller that calculates the instructed braking force to be used and the driver that operates in the event that one of the two master controllers fails. [Figure 6]Figure 6 is a flowchart showing the series of processes performed by the master controller. [Figure 7] Figure 7 is a flowchart showing the series of processes performed by the slave controller. [Figure 8] Figure 8 is a block diagram showing the configuration of the modified brake system. [Modes for carrying out the invention]

[0009] An embodiment of the brake system will be described below with reference to Figures 1 to 7. <Outline of the vehicle configuration> Figure 1 illustrates a vehicle 10 to which the brake system is applied. The vehicle 10 has wheels consisting of a left front wheel FL, a right front wheel FR, a left rear wheel RL, and a right rear wheel RR. The vehicle 10 has a first power supply 11 and a second power supply 12, separate from the first power supply 11, as sources of power supply for the brake system.

[0010] <Electric brakes in the braking system> As shown in Figures 1 and 2, the brake system 100 is equipped with four electric brakes. The four electric brakes correspond to the four wheels FL, FR, RL, and RR, respectively. Specifically, the four electric brakes include electric brake 20A which generates braking force on the left front wheel FL, electric brake 20B which generates braking force on the right front wheel FR, electric brake 20C which generates braking force on the left rear wheel RL, and electric brake 20D which generates braking force on the right rear wheel RR. Hereafter, the electric brakes 20A and 20B for the front wheels will be referred to as "front electric brakes 20A and 20B," and the electric brakes 20C and 20D for the rear wheels will be referred to as "rear electric brakes 20C and 20D."

[0011] Each of the multiple front-wheel electric brakes 20A and 20B is equipped with a rotating body 21, a friction member 22, an electric motor 23, a reduction mechanism 24, and a linear motion conversion mechanism 25. The rotating body 21 rotates integrally with the front wheels FL and FR. In the front-wheel electric brakes 20A and 20B, the rotational motion of the electric motor 23 is reduced by the reduction mechanism 24 and output to the linear motion conversion mechanism 25. The rotational motion input to the linear motion conversion mechanism 25 is then converted into linear motion by the linear motion conversion mechanism 25 and output to the friction member 22. In other words, the front-wheel electric brakes 20A and 20B adjust the braking force generated on the front wheels FL and FR by controlling the electric motor 23. The electric motor 23 is a double-wound motor.

[0012] Each of the rear-wheel electric brakes 20C and 20D is equipped with a rotating body 31, a friction member 32, an electric motor 33, a reduction mechanism 34, and a linear motion conversion mechanism 35. The rotating body 31 rotates integrally with the rear wheels RL and RR. In the electric brakes 20C and 20D, the rotational motion of the electric motor 33 is reduced by the reduction mechanism 34 and output to the linear motion conversion mechanism 35. The rotational motion input to the linear motion conversion mechanism 35 is then converted into linear motion by the linear motion conversion mechanism 35 and output to the friction member 32. In other words, the rear-wheel electric brakes 20C and 20D adjust the braking force generated on the rear wheels RL and RR by controlling the electric motor 33. Note that, unlike the electric motor 23, the electric motor 33 is not a double-wound motor.

[0013] In this embodiment, the electric motors 23 and 33 of the multiple electric brakes 20A to 20D correspond to "electric actuators". In particular, the electric motor 23 of the electric brake 20A for the left front wheel corresponds to the "first electric actuator", and the electric motor 23 of the electric brake 20B for the right front wheel corresponds to the "second electric actuator". The electric motor 33 of the electric brake 20C for the left rear wheel corresponds to the "third electric actuator", and the electric motor 33 of the electric brake 20D for the right rear wheel corresponds to the "fourth electric actuator". The left front wheel FL, which generates braking force when driven by the first electric actuator, is also called the "first wheel". The right front wheel FR, which generates braking force when driven by the second electric actuator, is also called the "second wheel". The left rear wheel RL, which generates braking force when driven by the third electric actuator, is also called the "third wheel". The right rear wheel RR, which generates braking force when driven by the fourth electric actuator, is also called the "fourth wheel".

[0014] <Brake system braking control device> The brake system 100 is equipped with a braking control device 40 that controls four electric brakes 20A to 20D. The braking control device 40 has a left front wheel control unit 41A, a right front wheel control unit 41B, a left rear wheel control unit 41C, and a right rear wheel control unit 41D. The left front wheel control unit 41A controls the electric brake 20A for the left front wheel. The right front wheel control unit 41B controls the electric brake 20B for the right front wheel. The left rear wheel control unit 41C controls the electric brake 20C for the left rear wheel. The right rear wheel control unit 41D controls the electric brake 20D for the right rear wheel. Each of the control units 41A to 41D is configured to send and receive information via the braking control device internal communication 42. For example, the braking control device internal communication 42 is a CAN bus. "CAN" is an abbreviation for "Controller Area Network".

[0015] The left front wheel control unit 41A includes a master controller 50A and a slave controller 60A. The master controller 50A and the slave controller 60A are configured to send and receive information from each other within the left front wheel control unit 41A.

[0016] The right front wheel control unit 41B has a master controller 50B and a slave controller 60B. The master controller 50B and the slave controller 60B are respectively configured so that they can transmit and receive information to and from each other within the right front wheel control unit 41B.

[0017] The left rear wheel control unit 41C has a slave controller 60C while not having a master controller. The right rear wheel control unit 41D has a slave controller 60D while not having a master controller.

[0018] The plurality of controllers 50A, 50B, 60A to 60D constituting the brake system 100 can be classified into a first controller group supplied with power from the first power source 11 and a second controller group supplied with power from the second power source 12. The first controller group includes the master controller 50A among the plurality of master controllers 50A, 50B and includes the slave controllers 60B and 60C among the plurality of slave controllers 60A to 60D. On the other hand, the second controller group includes the master controller 50B among the plurality of master controllers 50A, 50B and includes the slave controllers 60A and 60D among the plurality of slave controllers 60A to 60D. Note that power is not supplied from the second power source 12 to the plurality of controllers 50A, 60B, 60C constituting the first controller group. Power is not supplied from the first power source 11 to the plurality of controllers 50B, 60A, 60D constituting the second controller group.

[0019] In this embodiment, the master controller 50A corresponds to the "first master controller", and the master controller 50B corresponds to the "second master controller". Also, the slave controller 60B that constitutes the first controller group corresponds to the "first slave controller", and the slave controller 60C that constitutes the first controller group corresponds to the "second slave controller". Further, the slave controller 60A that constitutes the second controller group corresponds to the "third slave controller", and the slave controller 60D that constitutes the second controller group corresponds to the "fourth slave controller".

[0020] Both the master controller 50A of the first controller group and the slave controller 60A of the second controller group control the first electric actuator. In this embodiment, since the electric motor 23 of the left front wheel control unit 41A corresponds to the first electric actuator, the master controller 50A corresponds to the "first specified controller", and the slave controller 60A corresponds to the "second specified controller". As described above, the electric motor 23 is a dual-wound motor. Therefore, the master controller 50A adjusts the current flowing through the first winding of the two windings of the electric motor 23, and the slave controller 60A adjusts the current flowing through the second winding of the two windings of the electric motor 23. Thus, when at least one of the master controller 50A and the slave controller 60A operates, the braking force generated on the left front wheel FL can be adjusted by driving the electric motor 23.

[0021] Both the master controller 50B of the second controller group and the slave controller 60B of the first controller group control the second electric actuator. In this embodiment, since the electric motor 23 of the right front wheel control unit 41B corresponds to the second electric actuator, the master controller 50B corresponds to the "fourth defining controller" and the slave controller 60B corresponds to the "third defining controller". As described above, the electric motor 23 is a double-wound motor. Therefore, the master controller 50B adjusts the current flowing through the first winding of the two windings of the electric motor 23, and the slave controller 60B adjusts the current flowing through the second winding of the two windings of the electric motor 23. Thus, when at least one of the master controller 50B and the slave controller 60B is operating, the braking force generated on the right front wheel FR can be adjusted by driving the electric motor 33.

[0022] Among the first group of controllers, a slave controller 60C, which is different from the master controller 50A and slave controller 60B, controls the third electric actuator. In this embodiment, since the electric motor 33 of the left rear wheel control unit 41C corresponds to the third electric actuator, the slave controller 60C can adjust the braking force generated on the left rear wheel RL by driving the electric motor 33 of the left rear wheel control unit 41C.

[0023] Among the second group of controllers, a slave controller 60D, which is different from the master controller 50B and slave controller 60A, controls the fourth electric actuator. In this embodiment, since the electric motor 33 of the right rear wheel control unit 41D corresponds to the fourth electric actuator, the slave controller 60D can adjust the braking force generated on the right rear wheel RR by driving the electric motor 33 of the right rear wheel control unit 41D.

[0024] Each of the multiple master controllers 50A and 50B has a first driver 51 and a master microcontroller 52. The master microcontroller 52 includes an execution unit and a storage unit that stores the control program executed by the execution unit. For example, the execution unit is a CPU. Since the electric motor 23 is a double-wound motor, the first driver 51 is electrically connected only to the first winding of the two windings of the electric motor 23. The execution unit of the master microcontroller 52 operates the first driver 51 by executing a control program. As a result, the execution unit can drive the electric motor 23 by adjusting the current flowing through the first winding of the electric motor 23.

[0025] Each of the slave controllers 60A to 60D has a second driver 61 and a slave microcontroller 62. The slave microcontroller 62 includes an execution unit and a storage unit that stores the control program executed by the execution unit. For example, the execution unit is a CPU. Since the electric motor 23 is a double-wound motor, the second driver 61 is electrically connected only to the second winding of the electric motor 23. The execution unit of the slave microcontroller 62 in slave controllers 60A and 60B activates the second driver 61 by executing a control program. As a result, the execution unit can drive the electric motor 23 by adjusting the current flowing through the second winding of the electric motor 23.

[0026] Furthermore, the execution unit of the slave microcontroller 62 in the slave controllers 60C and 60D activates the second driver 61 by executing a control program. This allows the execution unit to drive the electric motor 33 by adjusting the current flowing through the windings of the electric motor 33.

[0027] Here, multiple master microcontrollers 52 communicate with other devices mounted on the vehicle besides the brake system 100 via the in-vehicle network 43. On the other hand, multiple slave microcontrollers 62 are not connected to the in-vehicle network 43. For example, the in-vehicle network 43 is a CAN bus. By connecting the master microcontrollers 52 to the in-vehicle network 43 while not connecting the slave microcontrollers 62 to the in-vehicle network 43, it becomes unnecessary to make the slave microcontrollers 62 security-enabled microcontrollers. As a result, the brake system 100 can be configured at a low cost. The slave microcontrollers 62 transmit and receive information only within the brake system 100 using the brake control device internal communication 42.

[0028] Incidentally, in the brake system 100, the left front wheel control unit 41A and the electric brake 20A are unitized to form the brake unit for the left front wheel. The right front wheel control unit 41B and the electric brake 20B are unitized to form the brake unit for the right front wheel. The left rear wheel control unit 41C and the electric brake 20C are unitized to form the brake unit for the left rear wheel. The right rear wheel control unit 41D and the electric brake 20D are unitized to form the brake unit for the right rear wheel.

[0029] <Controller Functional Configuration> Refer to Figure 2 to explain the controller's functional configuration. The execution units of the multiple master controllers 50A and 50B function as a braking force calculation unit M11 and a driver control unit M13, respectively, by executing a control program. The braking force calculation unit M11 and the driver control unit M13 are functional units for driving electric motors.

[0030] The braking force calculation unit M11 calculates the braking force generated on the wheels by the drive of the electric motor of the electric brake. For example, based on the required deceleration value of the vehicle 10, the braking force calculation unit M11 calculates the instructed braking force, which is the instructed value of the braking force to be generated on the wheels, for each wheel FL, FR, RL, and RR. That is, the braking force calculation unit M11 calculates the instructed braking force FbA for the left front wheel FL, the instructed braking force FbB for the right front wheel FR, the instructed braking force FbC for the left rear wheel RL, and the instructed braking force FbD for the right rear wheel RR.

[0031] The driver control unit M13 adjusts the power supplied to the electric motor 23 of the front wheel electric brake by activating the first driver 51 according to the calculation result of the braking force calculation unit M11. Specifically, the driver control unit M13 of the left front wheel control unit 41A adjusts the power supplied to the electric motor 23 of the left front wheel electric brake 20A by activating the first driver 51 based on the instructed braking force FbA for the left front wheel FL. The driver control unit M13 of the right front wheel control unit 41B adjusts the power supplied to the electric motor 23 of the right front wheel electric brake 20B by activating the first driver 51 based on the instructed braking force FbB for the right front wheel FR.

[0032] The execution units of the multiple slave controllers 60A to 60D each function as a driver control unit M23 by executing a control program. The driver control unit M23 is a functional unit for driving electric motors. Note that the execution units of the slave controllers 60A to 60D do not function as braking force calculation units.

[0033] The driver control unit M23 of the front wheel slave controllers 60A and 60B adjusts the power supplied to the electric motor 23 of the front wheel electric brake by activating the second driver 61 according to the calculation result of the braking force calculation unit M11. Specifically, the driver control unit M23 of the left front wheel control unit 41A adjusts the power supplied to the electric motor 23 of the left front wheel electric brake 20A by activating the second driver 61 based on the instructed braking force FbA for the left front wheel FL. The driver control unit M23 of the right front wheel control unit 41B adjusts the power supplied to the electric motor 23 of the right front wheel electric brake 20B by activating the second driver 61 based on the instructed braking force FbB for the right front wheel FR.

[0034] The driver control unit M23 of the rear wheel slave controllers 60C and 60D adjusts the power supplied to the electric motor 33 of the rear wheel electric brake by activating the second driver 61 according to the calculation result of the braking force calculation unit M11. Specifically, the driver control unit M23 of the left rear wheel control unit 41C adjusts the power supplied to the electric motor 33 of the left rear wheel electric brake 20C by activating the second driver 61 based on the instructed braking force FbC for the left rear wheel RL. The driver control unit M23 of the right rear wheel control unit 41D adjusts the power supplied to the electric motor 33 of the right rear wheel electric brake 20D by activating the second driver 61 based on the instructed braking force FbD for the right rear wheel RR.

[0035] <Braking control under normal conditions> Referring to Figure 3, the braking control under normal conditions will be explained. Here, "normal" refers to the state of the braking control device 40 in which power is supplied to the brake system 100 from both the first power supply 11 and the second power supply 12, and all of the master controllers 50A and 50B are operating normally. In Figures 3 to 5, "MC1" refers to the master controller 50A, and "MC2" refers to the master controller 50B. Also, "SC1" refers to the slave controller 60A, "SC2" refers to the slave controller 60B, "SC3" refers to the slave controller 60C, and "SC4" refers to the slave controller 60D.

[0036] The left front wheel control unit 41A operates based on the instructed braking force FbA calculated by the braking force calculation unit M11 of the master controller 50A. Specifically, the driver control unit M13 of the master controller 50A operates the first driver 51 based on the instructed braking force FbA calculated by the braking force calculation unit M11 of the master controller 50A. In addition, the driver control unit M23 of the slave controller 60A operates the second driver 61 based on the instructed braking force FbA calculated by the braking force calculation unit M11 of the master controller 50A.

[0037] In the following description, the instructed braking force calculated by the braking force calculation unit M11 of the master controller 50A will be referred to as the "instructed braking force calculated by the master controller 50A." Similarly, the instructed braking force calculated by the braking force calculation unit M11 of the master controller 50B will be referred to as the "instructed braking force calculated by the master controller 50B."

[0038] The right front wheel control unit 41B operates based on the instructed braking force FbB calculated by the master controller 50B. Specifically, the driver control unit M13 of the master controller 50B activates the first driver 51 based on the instructed braking force FbB calculated by the master controller 50B. In addition, the driver control unit M23 of the slave controller 60B activates the second driver 61 based on the instructed braking force FbB calculated by the master controller 50B.

[0039] The left rear wheel control unit 41C operates based on the instructed braking force FbC calculated by the master controller 50B. That is, the driver control unit M23 of the slave controller 60C operates the second driver 61 based on the instructed braking force FbC calculated by the master controller 50B.

[0040] The right rear wheel control unit 41D operates based on the instructed braking force FbD calculated by the master controller 50A. That is, the driver control unit M23 of the slave controller 60D operates the second driver 61 based on the instructed braking force FbD calculated by the master controller 50A.

[0041] <Braking control when power supply from the power source to the brake system is interrupted> Referring to Figure 4, the braking control in a case where power is supplied to the brake system 100 from one of the first power supply 11 and the second power supply 12, but power supply to the brake system 100 from the other is stopped, will be explained.

[0042] First, we will explain the case where power supply from the first power source 11 to the brake system 100 is stopped. In this case, the controllers 50A, 60B, and 60C that make up the first controller group will not operate.

[0043] The left front wheel control unit 41A operates based on the instructed braking force FbA calculated by the master controller 50B. That is, the driver control unit M23 of the slave controller 60A operates the second driver 61 based on the instructed braking force FbA calculated by the master controller 50B.

[0044] The right front wheel control unit 41B operates based on the instructed braking force FbB calculated by the master controller 50B. That is, the driver control unit M13 of the master controller 50B operates the first driver 51 based on the instructed braking force FbB calculated by the master controller 50B.

[0045] If power to the slave controller 60C is cut off, the slave controller 60C's second driver 61 will not operate. As a result, the left rear wheel control unit 41C will not operate, and the slave controller 60C will not be able to adjust the braking force generated on the left rear wheel RL.

[0046] The right rear wheel control unit 41D operates based on the instructed braking force FbD calculated by the master controller 50B. That is, the driver control unit M23 of the slave controller 60D operates the second driver 61 based on the instructed braking force FbD calculated by the master controller 50B.

[0047] Conversely, let's consider the case where power supply from the second power source 12 to the brake system 100 is stopped. In this case, the controllers 50B, 60A, and 60D that make up the second controller group will not operate.

[0048] The left front wheel control unit 41A operates based on the instructed braking force FbA calculated by the master controller 50A. That is, the driver control unit M13 of the master controller 50A operates the first driver 51 based on the instructed braking force FbA calculated by the master controller 50A.

[0049] The right front wheel control unit 41B operates based on the instructed braking force FbB calculated by the master controller 50A. That is, the driver control unit M23 of the slave controller 60B operates the second driver 61 based on the instructed braking force FbB calculated by the master controller 50A.

[0050] The left rear wheel control unit 41C operates based on the instructed braking force FbC calculated by the master controller 50A. That is, the driver control unit M23 of the slave controller 60C operates the second driver 61 based on the instructed braking force FbC calculated by the master controller 50A.

[0051] If power to the slave controller 60D is cut off, the slave controller 60D's second driver 61 will not operate. As a result, the right rear wheel control unit 41D will not operate, and the slave controller 60D will not be able to adjust the braking force generated on the right rear wheel RR.

[0052] <Braking control in the event of master controller failure> Referring to Figure 5, we will now describe braking control in the case where one of the multiple master controllers 50A and 50B is functioning normally, but the other fails. Here, we will assume that power is supplied to the brake system 100 from both the first power supply 11 and the second power supply 12.

[0053] First, let's explain what happens when the master controller 50A fails. The left front wheel control unit 41A operates based on the instructed braking force FbA calculated by the master controller 50B. That is, the slave controller 60A operates the second driver 61 based on the instructed braking force FbA calculated by the master controller 50B. However, because the master controller 50A is not functioning, the first driver 51 of the left front wheel control unit 41A cannot operate.

[0054] The right front wheel control unit 41B operates based on the instructed braking force FbB calculated by the master controller 50B. Specifically, the driver control unit M13 of the master controller 50B activates the first driver 51 based on the instructed braking force FbB calculated by the master controller 50B. In addition, the driver control unit M23 of the slave controller 60B activates the second driver 61 based on the instructed braking force FbB calculated by the master controller 50B.

[0055] The left rear wheel control unit 41C operates based on the instructed braking force FbC calculated by the master controller 50B. That is, the driver control unit M23 of the slave controller 60C operates the second driver 61 based on the instructed braking force FbC calculated by the master controller 50B.

[0056] The right rear wheel control unit 41D operates based on the instructed braking force FbD calculated by the master controller 50B. That is, the driver control unit M23 of the slave controller 60D operates the second driver 61 based on the instructed braking force FbD calculated by the master controller 50B.

[0057] Next, we will explain what happens when the master controller 50B fails. The left front wheel control unit 41A operates based on the instructed braking force FbA calculated by the master controller 50A. Specifically, the driver control unit M13 of the master controller 50A operates the first driver 51 based on the instructed braking force FbA calculated by the master controller 50A. In addition, the driver control unit M23 of the slave controller 60A operates the second driver 61 based on the instructed braking force FbA calculated by the master controller 50A.

[0058] The right front wheel control unit 41B operates based on the instructed braking force FbB calculated by the master controller 50A. That is, the slave controller 60B operates the second driver 61 based on the instructed braking force FbB calculated by the master controller 50A. However, since the master controller 50B is not functioning, the first driver 51 of the right front wheel control unit 41B cannot operate.

[0059] The left rear wheel control unit 41C operates based on the instructed braking force FbC calculated by the master controller 50A. That is, the driver control unit M23 of the slave controller 60C operates the second driver 61 based on the instructed braking force FbC calculated by the master controller 50A.

[0060] The right rear wheel control unit 41D operates based on the instructed braking force FbD calculated by the master controller 50A. That is, the driver control unit M23 of the slave controller 60D operates the second driver 61 based on the instructed braking force FbD calculated by the master controller 50A.

[0061] <Processing flow executed by the master microcontroller of the master controller> Referring to Figure 6, the master-side processing, which is a series of processes performed by the master microcontroller 52 of the master controllers 50A and 50B, will be explained. The master microcontroller 52 repeatedly executes the master-side processing at predetermined control cycles.

[0062] In step S11, the master microcontroller 52 functions as a braking force calculation unit M11 to calculate the instructed braking forces FbA to FbD for multiple wheels FL, FR, RL, and RR. That is, both the master microcontroller 52 of master controller 50A and the master microcontroller 52 of master controller 50B calculate the instructed braking forces FbA to FbD for multiple wheels FL, FR, RL, and RR, respectively.

[0063] In step S13, the master microcontroller 52 transmits the instructed braking force calculated in step S11. Specifically, the master microcontroller 52 of the master controller 50A transmits the instructed braking forces FbB, FbC, and FbD for the other wheels FR, RL, and RR (excluding the left front wheel FL) to the braking control device internal communication 42. The master microcontroller 52 of the master controller 50A also transmits the instructed braking force FbA for the left front wheel FL to the slave controller 60A. On the other hand, the master microcontroller 52 of the master controller 50B transmits the instructed braking forces FbA, FbC, and FbD for the other wheels FL, RL, and RR (excluding the right front wheel FR) to the braking control device internal communication 42. The master microcontroller 52 of the master controller 50B also transmits the instructed braking force FbB for the right front wheel FR to the slave controller 60B.

[0064] In step S15, the master microcontroller 52 functions as a driver control unit M13, activating the first driver 51 based on the instructed braking force. Specifically, the master microcontroller 52 of the master controller 50A activates the first driver 51 of the electric brake 20A based on the instructed braking force FbA for the left front wheel FL, which it has calculated itself. On the other hand, the master microcontroller 52 of the master controller 50B activates the first driver 51 of the electric brake 20B based on the instructed braking force FbB for the right front wheel FR, which it has calculated itself. After that, the master microcontroller 52 temporarily terminates its master-side processing.

[0065] <Processing flow executed by the slave microcontroller of the slave controller> Referring to Figure 7, the slave-side processing, which is a series of processes performed by the slave microcontroller 62 of the slave controllers 60A to 60D, will be explained. The slave microcontroller 62 repeatedly executes the slave-side processing at predetermined control cycles.

[0066] In step S21, the slave microcontroller 62 acquires the instruction braking force to activate the second driver 61. Specifically, the slave microcontroller 62 of the slave controller 60A of the left front wheel control unit 41A acquires the commanded braking force FbA calculated by the master controller 50A when it receives the commanded braking force FbA from the master controller 50A. Even if the slave microcontroller 62 of the slave controller 60A does not receive the commanded braking force FbA from the master controller 50A, if it receives the commanded braking force FbA calculated by the master controller 50B from the braking control device internal communication 42, it acquires the commanded braking force FbA calculated by the master controller 50B.

[0067] The slave microcontroller 62 of the slave controller 60B of the right front wheel control unit 41B acquires the commanded braking force FbB calculated by the master controller 50B when it receives the commanded braking force FbB from the master controller 50B. Even if the slave microcontroller 62 of the slave controller 60B does not receive the commanded braking force FbB from the master controller 50B, if it receives the commanded braking force FbB calculated by the master controller 50A from the internal communication 42 of the braking control device, it acquires the commanded braking force FbB calculated by the master controller 50A.

[0068] The slave microcontroller 62 of the slave controller 60C of the left rear wheel control unit 41C acquires the commanded braking force FbC calculated by the master controller 50B from the internal communication 42 of the braking control device if it can acquire the commanded braking force FbC calculated by the master controller 50B. Even if the slave microcontroller 62 of the slave controller 60C cannot receive the commanded braking force FbC calculated by the master controller 50B, if it can receive the commanded braking force FbC calculated by the master controller 50A from the internal communication 42 of the braking control device, it acquires the commanded braking force FbC calculated by the master controller 50A.

[0069] The slave microcontroller 62 of the slave controller 60D of the right rear wheel control unit 41D acquires the commanded braking force FbD calculated by the master controller 50A from the internal communication 42 of the braking control device if it can acquire the commanded braking force FbD calculated by the master controller 50A. Even if the slave microcontroller 62 of the slave controller 60D cannot receive the commanded braking force FbD calculated by the master controller 50A, if it can receive the commanded braking force FbD calculated by the master controller 50B from the internal communication 42 of the braking control device, it acquires the commanded braking force FbD calculated by the master controller 50B.

[0070] In step S23, the slave microcontroller 62 activates the second driver 61 based on the instructed braking force acquired in step S21. Specifically, the slave microcontroller 62 of the slave controller 60A of the left front wheel control unit 41A activates the second driver 61 of the electric brake 20A based on the instructed braking force FbA. The slave microcontroller 62 of the slave controller 60B of the right front wheel control unit 41B activates the second driver 61 of the electric brake 20B based on the instructed braking force FbB. The slave microcontroller 62 of the slave controller 60C of the left rear wheel control unit 41C activates the second driver 61 of the electric brake 20C based on the instructed braking force FbC. The slave microcontroller 62 of the slave controller 60D of the right rear wheel control unit 41D activates the second driver 61 of the electric brake 20D based on the instructed braking force FbD. After that, the slave microcontroller 62 temporarily terminates the slave-side processing.

[0071] <Operation and Effects of This Embodiment> (1) Even if the power supply from the first power source 11 to the brake system 100 is stopped, if power is supplied to the brake system 100 from the second power source 12, the controllers of the second controller group will operate. As a result, braking force can be generated on three of the four wheels FL, FR, RL, and RR. Conversely, even if the power supply from the second power source 12 to the brake system 100 is stopped, if power is supplied to the brake system 100 from the first power source 11, the controllers of the first controller group will operate. As a result, braking force can be generated on three of the four wheels FL, FR, RL, and RR. Therefore, the brake system 100 can suppress the decrease in the braking force of the vehicle 10 when the power supply from either the first power source 11 or the second power source 12 is stopped.

[0072] Furthermore, if the controllers of the first controller group are operational but the controllers of the second controller group are not, braking force can be generated on the other wheels FL, FR, and RL, excluding the right rear wheel RR. Conversely, if the controllers of the second controller group are operational but the controllers of the first controller group are not, braking force can be generated on the other wheels FL, FR, and RR, excluding the left rear wheel RL.

[0073] In addition, the first group of controllers is not supplied with power from the second power supply 12, but is supplied with power from the first power supply 11. The second group of controllers is not supplied with power from the first power supply 11, but is supplied with power from the first power supply 11. This prevents a ground fault in either the controller of the first group of controllers or the controller of the second group of controllers from simultaneously lowering the potential of the first power supply 11 and the second power supply 12, which would prevent power from being supplied to the brake system 100.

[0074] (2) Consider the case where the electric motor 23 of the front wheel control unit has only one winding. In this case, in order to enable the driver of the electric motor 23 to be operated by either the master controller or the slave controller of the front wheel control unit, a switching circuit may be provided in the front wheel control unit to switch the controller that controls the driver between the master controller and the slave controller. When switching the controller that controls the driver from one of the master controller and the slave controller to the other, it becomes necessary to activate the switching circuit, and there is a risk that the control of the electric motor 23 may be temporarily interrupted during the switching process.

[0075] In this regard, the brake system 100 has a double-wound electric motor 23 in the front wheel control unit. Of the two windings, the first winding is electrically connected to the first driver 51 of the master controller, and the second winding is electrically connected to the second driver 61 of the slave controller. When both the master controller and the slave controller are operating, both the first driver 51 and the second driver 61 are operating. Therefore, even if the operation of one of the master controller or the slave controller stops while the electric motor 23 is being driven, control of the electric motor 23 can be continued. In other words, it is possible to prevent the control of the electric motor 23 from being temporarily interrupted.

[0076] (3) The electric motor 23 of the front wheel control unit is a double-wound motor, and the front wheel control unit is equipped with both a master controller and a slave controller. Furthermore, one of the master controller and the slave controller constitutes the first controller group, and the other constitutes the second controller group. Therefore, even if the power supply to the brake system 100 is stopped from either the first power supply 11 or the second power supply 12, braking force can still be generated in multiple front wheels FL,FR.

[0077] (4) Multiple master controllers 50A and 50B each calculate the instruction braking forces FbA to FbD for multiple wheels FL, FR, RL, and RR. Therefore, even if only one of the multiple master controllers 50A and 50B fails, the multiple control units 41A to 41D can each acquire the instruction braking force, and thus the multiple control units 41A to 41D can each drive the electric motors. Thus, even if only one of the multiple master controllers 50A and 50B fails, braking force can be generated for multiple wheels FL, FR, RL, and RR.

[0078] (5) Unlike the master controllers 50A and 50B, the slave controllers 60A to 60D do not have the function to calculate the instructed braking force FbA to FbD. Therefore, a less functional microcontroller can be used as the slave microcontroller 62 of the slave controllers 60A to 60D than the master microcontroller 52 of the master controllers 50A and 50B. In other words, the brake system 100 can suppress the decrease in the braking force of the vehicle 10 when power is stopped from one of the two power supplies 11 and 12, while suppressing an increase in cost. The term "less functional microcontroller" here includes having a lower operating frequency or fewer CPU cores compared to a non-less functional microcontroller.

[0079] (6) In this embodiment, since the electric brake 20A for the front wheels and the master controller 50A are unitized, the driver control unit M13 and the first driver 51 are located near the electric motor 23. The effects of this arrangement are described below. The driver control unit M13 needs to issue precise commands to the driver that operates the electric motor 23, and therefore needs to perform calculations at a faster control cycle than the internal communication 42 of the braking control device. Therefore, if the signals of the driver control unit M13 are transmitted and received via the internal communication 42 of the braking control device, the control accuracy of the electric motor 23 may decrease. On the other hand, the braking force calculation unit M11 does not need to perform calculations at a faster calculation cycle than the internal communication 42 of the braking control device, so even if the signals of the braking force calculation unit M11 are transmitted and received via the internal communication 42 of the braking control device, the control accuracy of the electric motor 23 does not decrease.

[0080] As described above, by unitizing the master controller 50A, which includes the braking force calculation unit M11, the driver control unit M13, and the first driver 51, with the electric brake 20A, the signals from the driver control unit M13 of the master controller 50A can be transmitted to the first driver 51 without having to send or receive them via the braking control device internal communication 42. Furthermore, because the master controller 50A and the electric brake 20A are unitized, the first driver 51 can directly supply power to the electric motor 23 of the electric brake 20A. Therefore, by utilizing the driver control unit M13 of the master controller 50A while transmitting the signals from the braking force calculation unit M11 to other control units via the braking control device internal communication 42, a redundant configuration can be achieved without increasing the number of microcontrollers, resulting in an inexpensive brake system. On the other hand, if the master controller is not integrated with the electric brake, the driver control unit of the master controller cannot be utilized. In other words, as mentioned above, the communication within the braking control device 42 cannot transmit signals at a faster frequency than the calculation cycle of the driver control unit M13. Therefore, if the front wheels are configured redundantly as in this embodiment, it is necessary to add one slave microcontroller to each of the front wheel control units integrated with the electric brake, increasing the number of microcontrollers in the brake system by two. Even if the master controller is not integrated with the electric brake, it is still possible to utilize the driver control unit of the master controller. However, in that case, the physical distance between the driver and the electric motor increases. In other words, signals from the driver control unit M13 to the driver cannot be transmitted or received via the communication within the braking control device 42. Therefore, if the driver control unit M13 is utilized, the physical placement of the driver control unit M13 and the driver must be in close proximity. This results in a longer path between the driver, which carries a large current, and the electric motor, leading to disadvantages such as increased wire harness costs and reduced driving efficiency of the electric motor due to increased wiring resistance. Thus, the configuration of this embodiment is advantageous.

[0081] In addition, in this embodiment, the left front wheel control unit 41A and the right front wheel control unit 41B have the same configuration, and the left rear wheel control unit 41C and the right rear wheel control unit 41D have the same configuration. Therefore, the units can be standardized, resulting in a less expensive brake system.

[0082] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0083] The electric motors in the front wheel electric brakes 20A and 20B are single-winding motors, and the control units 41A and 41B for the front wheels consist of only a slave controller among the master controller and slave controller configurations. In this case, the electric motors in the rear wheel electric brakes 20C and 20D are double-winding motors, and the control units 41C and 41D for the rear wheels consist of both a master controller and a slave controller configuration.

[0084] In this modification example, the left rear wheel RL corresponds to the first wheel, the right rear wheel RR corresponds to the second wheel, the left front wheel FL corresponds to the third wheel, and the right front wheel FR corresponds to the fourth wheel. Furthermore, the electric motor of the left rear wheel electric brake 20C corresponds to the first electric actuator, the electric motor of the right rear wheel electric brake 20D corresponds to the second electric actuator, the electric motor of the left front wheel electric brake 20A corresponds to the third electric actuator, and the electric motor of the right front wheel electric brake 20B corresponds to the fourth electric actuator. The master controller of the left rear wheel control unit, the slave controller of the right rear wheel control unit, and the slave controller of the left front wheel control unit constitute the first controller group. The master controller of the right rear wheel control unit, the slave controller of the left rear wheel control unit, and the slave controller of the right front wheel control unit constitute the second controller group. In this case, the master controller of the left rear wheel control unit corresponds to the first specified controller, and the slave controller of the left rear wheel control unit corresponds to the second specified controller. Furthermore, the slave controller of the right rear wheel control unit corresponds to the third-spec controller, and the master controller of the right rear wheel control unit corresponds to the fourth-spec controller.

[0085] Even with this configuration, braking force can be generated on all three wheels even if power supply to the brake system is cut off from either the first power supply 11 or the second power supply 12. Furthermore, braking force can be generated on the two rear wheels RL and RR even if power supply from either the first power supply 11 or the second power supply 12 is cut off.

[0086] An electric motor controlled by a control unit comprising both a master controller and a slave controller does not necessarily have to be a double-wound motor. In this case, it is preferable to provide a switching circuit in the control unit for switching between the master controller and the slave controller that controls the driver. With this configuration, if the operation of one of the controllers, the master controller or the slave controller, stops, the electric motor can be driven by the other controller operating the driver through the operation of the switching circuit.

[0087] • As a braking system, the brake system 1000 shown in Figure 8 can also be used. Referring to Figure 8, the braking control device 400 of the brake system 1000 will be described. The braking control device 400 comprises a left front wheel control unit 41A1, a right front wheel control unit 41B1, a left rear wheel control unit 41C, and a right rear wheel control unit 41D. The left front wheel control unit 41A1 has a master controller 50A1 and a master controller 50A2. Each of the master controllers 50A1 and 50A2 has a first driver 51 and a master microcontroller 52. Of the two windings of the electric motor 23 of the electric brake 20A for the left front wheel, the first driver 51 of master controller 50A1 is electrically connected to the first winding, and the first driver 51 of master controller 50A2 is electrically connected to the second winding.

[0088] The right front wheel control unit 41B1 has a slave controller 60B1 and a slave controller 60B2. These two slave controllers 60B1 and 60B2 each have a second driver 61 and a slave microcontroller 62. Of the two windings of the electric motor 23 of the electric brake 20B for the right front wheel, the second driver 61 of slave controller 60B1 is electrically connected to the first winding, and the second driver 61 of slave controller 60B2 is electrically connected to the second winding.

[0089] In the braking control device 400, the master controller 50A1 and slave controller 60B1 are classified into a first controller group, and the master controller 50A2 and slave controller 60B2 are classified into a second controller group. In this case, the master controller 50A1 of the first controller group corresponds to the "first specified controller," and the master controller 50A2 of the second controller group corresponds to the "second specified controller." Furthermore, the slave controller 60B1 of the first controller group corresponds to the "third specified controller," and the slave controller 60B2 of the second controller group corresponds to the "fourth specified controller." Therefore, in the brake system 1000, braking force can be generated on all three wheels even if the power supply from the first power supply 11 is stopped, or even if the power supply from the second power supply 12 is stopped.

[0090] Furthermore, as a configuration different from that shown in Figure 8, the brake system 1000 may also include a left rear wheel control unit with a master controller, a right rear wheel control unit with a master controller, a left front wheel control unit with a first slave controller and a second slave controller, and a right front wheel control unit with a first slave controller and a second slave controller. In this configuration, even if the power supply from the first power supply 11 is stopped, or if the power supply from the second power supply 12 is stopped, braking force can be generated on all three wheels. In this configuration, since the master controller is located at the rear of the vehicle, it is less likely that both master controllers will fail in the event of an impact to the front of the vehicle, and the units can also be standardized.

[0091] Alternatively, two master controllers may be placed one each in the front wheel control unit and the rear wheel control unit. In this configuration, it is less likely that both master controllers will fail in the event of an impact to the front or rear of the vehicle.

[0092] The master controller 50A may calculate the instructed braking force FbB for the right front wheel FR and the instructed braking force FbC for the left rear wheel RL only when the master controller 50B is unable to calculate the instructed braking force. The cases in which the master controller 50B is unable to calculate the instructed braking force include cases where power to the master controller 50B is cut off and cases where a malfunction or other abnormality occurs in the master controller 50B.

[0093] Similarly, the master controller 50B may calculate the instructed braking force FbA for the left front wheel FL and the instructed braking force FbD for the right rear wheel RR only when the master controller 50A is unable to calculate the instructed braking force. The cases in which the master controller 50A is unable to calculate the instructed braking force include cases where power to the master controller 50A is cut off and cases where a malfunction or other abnormality occurs in the master controller 50A.

[0094] If the brake system 100 is functioning normally, both the left rear wheel control unit 41C and the right rear wheel control unit 41D may operate the second driver 61 based on the instructed braking force calculated by the master controller 50A. Alternatively, both the left rear wheel control unit 41C and the right rear wheel control unit 41D may operate the second driver 61 based on the instructed braking force calculated by the master controller 50B.

[0095] The electric actuator may be an actuator other than an electric motor, as long as the electric brake can generate braking force on the wheels by being driven by the electric actuator.

[0096] The electric brake does not have to be a dry electric brake like the one shown in Figure 1, as long as it is a brake that can generate a braking force on the wheel in proportion to the amount of drive of the electric actuator. For example, the electric brake may be a wet electric brake equipped with an electric cylinder powered by an electric motor. Alternatively, for example, some of the electric brakes may be dry electric brakes, and the remaining electric brakes may be wet electric brakes.

[0097] • The above embodiment describes a vehicle with four wheels, but the number of wheels is not limited to four. For example, if the number of wheels becomes six, it is preferable to provide the additional two wheels with a brake unit that combines a control unit with the same configuration as the rear wheel control unit and an electric brake with the same configuration as the rear wheel electric brake. In this case, it is preferable to supply power to the brake units for the additional two wheels from different power sources. With this configuration, even if one power source is lost, the braking force of four out of six wheels can be guaranteed.

[0098] A microcontroller can be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits that perform at least some of the various processes, or a combination thereof. Examples of dedicated hardware include application-specific integrated circuits (ASICs). The processor includes a CPU and memory such as RAM and ROM, where memory stores program code or instructions configured to cause the CPU to perform processes. Memory, or storage medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0099] In this specification, the expression "at least one" means "one or more" of the desired options. For example, if there are two options, "at least one" means either "only one option" or "both of the two options." As another example, if there are three or more options, "at least one" means either "only one option" or "a combination of two or more options."

[0100] <Other technological ideas> The technical concepts that can be understood from the above embodiments and modified examples are described in the appendix. [Note 1] The first electric actuator and the second electric actuator are preferably driven to generate braking force on the left and right front wheels of the vehicle.

[0101] [Note 2] The first electric actuator is an actuator that is driven to generate braking force on the first wheel. The second electric actuator is an actuator that is driven to generate braking force on the second wheel, The third electric actuator is an actuator that is driven to generate braking force on the third wheel, The fourth electric actuator is an actuator that drives to generate braking force on the fourth wheel, The aforementioned first defining controller is the aforementioned first master controller, The third defining controller is preferably the second master controller.

[0102] [Note 3] The braking force calculation unit of the first master controller is The braking force generated on the first wheel by driving the first electric actuator is calculated, It is preferable to calculate the braking force generated on the fourth wheel by driving the fourth electric actuator.

[0103] [Note 4] The braking force calculation unit of the second master controller is The braking force generated on the second wheel by driving the second electric actuator is calculated, It is preferable to calculate the braking force generated on the third wheel by driving the third electric actuator.

[0104] [Note 5] The second specified controller is the third slave controller, The fourth defining controller is preferably the first slave controller. [Explanation of symbols]

[0105] 10... Vehicles 11...1st power supply 12…Second power supply 100, 1000… Brake system 20A~20D...Electric brake 23, 33… Electric motor (an example of an electric actuator) 50A, 50B, 50A1, 50A2… Master Controller 51…First driver 52...Master Microcontroller 60A~60D, 60B1, 60B2… Slave controllers 61...Second driver 62... Slave microcontroller FL, FR, RL, RR…wheels M11...braking force calculation section M13...Driver control unit M23... Driver control unit

Claims

1. A brake system applicable to a vehicle equipped with a first power source and a second power source separate from the first power source, The first to fourth electric actuators generate braking force on each of the first to fourth wheels of the vehicle, A driver that adjusts the power supplied from the first electric actuator to any one of the fourth electric actuators, a braking force calculation unit that calculates the braking force generated from the first wheel to the fourth wheel by the driving of the fourth electric actuator from the first electric actuator, and a plurality of master controllers including a driver control unit that operates the driver according to the calculation result of the braking force calculation unit, The system comprises a driver that adjusts the power supplied from the first electric actuator to any one of the fourth electric actuators, and a plurality of slave controllers, each including a driver control unit that operates the driver according to the calculation result of the braking force calculation unit of the master controller. The first master controller among the plurality of master controllers, and the first slave controller and the second slave controller among the plurality of slave controllers, constitute a first controller group in which power is supplied from the first power supply but not from the second power supply. The second master controller among the plurality of master controllers, and the third and fourth slave controllers among the plurality of slave controllers, constitute a second controller group in which power is not supplied from the first power supply but is supplied from the second power supply. Both the first defining controller among the first controller group and the second defining controller among the second controller group control the first electric actuator. Of the first group of controllers, the third standard controller, which is different from the first standard controller, and of the second group of controllers, the fourth standard controller, which is different from the second standard controller, both control the second electric actuator. Among the first group of controllers, one controller different from the first defining controller and the third defining controller controls the third electric actuator. Of the second group of controllers, one controller different from the second defining controller and the fourth defining controller controls the fourth electric actuator. Brake system.

2. The first electric actuator is a double-winding motor in which a winding electrically connected to the driver of the first defining controller and a winding electrically connected to the driver of the second defining controller are individually provided. The second electric actuator is a double-winding motor in which a winding electrically connected to the driver of the third defining controller and a winding electrically connected to the driver of the fourth defining controller are individually provided. The brake system according to claim 1.

3. At least one of the first master controller and the second master controller is unitized with any of the first to fourth electric actuators. The brake system according to claim 1 or claim 2.

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