Braking system

Abstract

A position detection device (20) has at least four sensors (21-24) that output signals corresponding to an operation amount of a brake pedal (12). The output signals of at least two sensors are input to a first ECU (31) distinguishably from each other. The output signals of at least two sensors other than the sensors that input the output signals to the first ECU (31) are input to a second ECU (32) distinguishably from each other. A signal transfer portion (33) can transfer the output signals of the at least two sensors input to one of the first ECU (31) and the second ECU (32) to the other distinguishably. The first ECU (31) and the second ECU (32) determine an output signal indicating an abnormal value based on the output signals of the at least four sensors (21-24), detect the operation amount of the brake pedal (12) based on a plurality of output signals other than the abnormal value, and perform drive control on a brake circuit (40).

Description

[0001] Related applications

[0002] This application is made based on Japanese Patent Application No. 2021-118218, filed on July 16, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to braking systems mounted on vehicles. Background Technology

[0004] Currently, there are known brake-by-wire systems where the electronic control unit controls the braking circuit based on the amount of pressure applied to the brake pedal by the driver, thus braking the vehicle. Hereinafter, the electronic control unit will be referred to as an "ECU." ECU is short for Electronic Control Unit.

[0005] The braking system described in Patent Document 1 is configured to utilize two ECUs to drive and control the braking circuit. This braking system is structured such that, in the event of a malfunction in one of the two ECUs, the other ECU is used to drive and control the braking circuit. Furthermore, in Patent Document 1, the two ECUs are referred to as a first and a second control and regulating unit.

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: U.S. Patent Application Publication No. 2021 / 0053540A1 Summary of the Invention

[0009] However, the braking system described in Patent Document 1 is a structure consisting of four sensors that detect the amount of brake pedal operation connected to two ECUs via two signal lines. Based on the inventors' research, they believe that the braking system described in Patent Document 1 has the following problems. Furthermore, regarding the structure of Patent Document 1, specifically, it will be described as follows: the first and second sensors are connected to the first ECU via a first signal line, and the third and fourth sensors are connected to the second ECU via a second signal line.

[0010] (1) If one of the first and second sensors fails, the first ECU cannot determine which sensor is faulty. Similarly, if one of the third and fourth sensors fails, the second ECU cannot determine which sensor is faulty.

[0011] (2) If one of the first and second sensors fails, and then one of the third and fourth sensors fails, neither the first ECU nor the second ECU can drive the braking circuit.

[0012] (3) When the signal indicating the amount of brake pedal operation transmitted from the first signal line to the first ECU is different from the signal indicating the amount of brake pedal operation transmitted from the second signal line to the second ECU, the first ECU and the second ECU cannot determine which of the two signals is correct.

[0013] The purpose of this disclosure is to provide a braking system that can improve the safety of vehicle braking control in the event of a sensor failure that outputs a signal corresponding to the amount of operation of the brake pedal.

[0014] According to one aspect of this disclosure, a braking system for driving control of a braking circuit that brakes a vehicle includes a brake pedal device, a position detection device, a first ECU, a second ECU, and a signal transmission unit. The brake pedal device has a brake pedal configured to swing about a predetermined axis relative to a fixed body fixed to the vehicle. The position detection device has at least four sensors that output signals corresponding to the amount of brake pedal operation performed by the driver. The output signals of at least two of the at least four sensors are input to the first ECU separately. The output signals of at least two of the at least four sensors other than the one inputting the output signal to the first ECU are input to the second ECU separately. The signal transmission unit can transmit the output signals of at least two sensors input to one of the first ECU and the second ECU separately to the other. Furthermore, the first ECU and the second ECU are configured to determine an output signal indicating an abnormal value based on the output signals of the at least four sensors, detect the amount of brake pedal operation based on multiple output signals other than the abnormal value, and perform driving control of the braking circuit.

[0015] Additionally, in the following explanation, the amount of brake pedal operation will sometimes be referred to simply as "operation amount".

[0016] In one of the aforementioned viewpoints, the output signals from at least two sensors input to one of the first and second ECUs can be separately transmitted to the other via a signal transmission unit. Thus, the first and second ECUs can separately acquire the output signals from at least four sensors. Therefore, the first and second ECUs can determine an output signal representing an abnormal value by comparing the output signals from at least four sensors. Consequently, the first and second ECUs can detect accurate operating quantities based on multiple normal output signals other than abnormal values, and perform drive control on the braking circuit. As a result, this braking system improves the safety of vehicle braking control in the face of sensor failures.

[0017] Furthermore, when at least two of the output signals from at least four sensors represent the same operational amount, the first ECU and the second ECU can identify the output signals from two sensors representing different operational amounts as output signals indicating abnormal values. Therefore, even in the face of multiple sensor failures, this braking system can detect the accurate brake pedal operation based on multiple normal output signals other than abnormal values, and perform drive control on the braking circuit.

[0018] In addition, the parenthesized reference symbols attached to each constituent element indicate an example of the correspondence between that constituent element and the specific constituent elements described in the embodiments described later. Attached Figure Description

[0019] Figure 1 This is a diagram showing a simplified structure of the braking system according to the first embodiment.

[0020] Figure 2 This is a side view of the brake pedal device included in the braking system of the first embodiment.

[0021] Figure 3 yes Figure 2 A cross-sectional view along line III-III.

[0022] Figure 4 yes Figure 3 A cross-sectional view of the position detection device at line IV-IV.

[0023] Figure 5 This is a characteristic diagram of the output signals of the first to fourth sensors.

[0024] Figure 6 This is a cross-sectional view of the position detection device included in the brake pedal device of the braking system of the second embodiment.

[0025] Figure 7 yes Figure 6A sectional view of line VII-VII.

[0026] Figure 8 yes Figure 6 A cross-sectional view of line VIII-VIII.

[0027] Figure 9 This is a diagram showing a simplified structure of the braking system according to the third embodiment. Detailed Implementation

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, in the following embodiments, the same or equivalent parts are labeled with the same symbols and their descriptions are omitted.

[0029] (First Implementation)

[0030] The first embodiment will be described with reference to the accompanying drawings. Figure 1 As shown, the braking system 1 of this embodiment is a system in which electronic control units 31 and 32 drive and control the braking circuit 40 based on electrical signals output from multiple sensors 21 to 24 provided on the brake pedal device 10, thereby braking the vehicle. That is, the braking system 1 of this embodiment is a brake-by-wire system. Hereinafter, the electronic control unit will be referred to as "ECU".

[0031] like Figure 1 As shown, the braking system 1 of this embodiment includes a brake pedal device 10, a position detection device 20, a first ECU 31, a second ECU 32, and a signal transmission unit 33.

[0032] The brake pedal device 10 includes a housing 11 fixed to the vehicle as a stationary body and a brake pedal 12 configured to swing relative to the housing 11. The brake pedal 12 swings about a predetermined axis CL when pressed by the driver. Furthermore, in this specification, "swinging" refers to rotation about the predetermined axis CL within a predetermined angular range in both the forward and reverse directions.

[0033] Additionally, a position detection device 20 having at least four sensors 21 to 24 is provided in the brake pedal assembly 10. Figure 1For convenience, the four sensors 21-24 located inside the housing 11 of the brake pedal device 10 are schematically shown on the side of the housing 11. In the description of the first embodiment, the four sensors 21-24 of the position detection device 20 are referred to as the first sensor 21, the second sensor 22, the third sensor 23, and the fourth sensor 24. The four sensors 21-24 output signals corresponding to the amount of operation of the brake pedal 12 by the driver. In addition, the amount of operation of the brake pedal 12 includes the angle of swing of the brake pedal 12 about a predetermined axis CL and the distance of movement of the brake pedal 12 or the component that moves with the brake pedal 12. The specific structure of the position detection device 20 will be described later.

[0034] The output signals of the four sensors 21-24 are input to the first ECU 31 and the second ECU 32 via the first to fourth signal lines 51-54. In the first embodiment, the first sensor 21 is electrically connected to the first ECU 31 via the first signal line 51, and the second sensor 22 is electrically connected to the first ECU 31 via the second signal line 52. Therefore, the output signals of the first sensor 21 and the second sensor 22 can be input to the first ECU 31 separately.

[0035] Furthermore, the third sensor 23 is electrically connected to the second ECU 32 via the third signal line 53, and the fourth sensor 24 is electrically connected to the second ECU 32 via the fourth signal line 54. Therefore, the output signals of the third sensor 23 and the fourth sensor 24 can be input to the second ECU 32 separately. Additionally, the first to fourth signal lines 51 to 54 are constructed, for example, by a wiring harness or a predefined in-vehicle LAN (Local Area Network).

[0036] Both the first ECU 31 and the second ECU 32 are composed of a microcomputer and its peripheral circuitry, including a processor for control and arithmetic processing, and storage units such as ROM and RAM for storing programs and data. The storage units are composed of non-movable physical storage media. The first ECU 31 and the second ECU 32 perform various control and arithmetic processing based on the programs stored in the storage units, controlling the operation of each device connected to the output port. Specifically, the first ECU 31 and the second ECU 32 are configured to detect the operation amount of the brake pedal 12 based on the output signals of the first to fourth sensors 21 to 24, and perform drive control on the brake circuit 40.

[0037] The first ECU 31 and the second ECU 32 are connected via an in-vehicle LAN, such as CAN (Controller Area Network) communication, which serves as the signal transmission unit 33, enabling them to exchange information. Therefore, the output signals of the first sensor 21 and the second sensor 22 input to the first ECU 31 can be transmitted separately to the second ECU 32 via the signal transmission unit 33. Similarly, the output signals of the third sensor 23 and the fourth sensor 24 input to the second ECU 32 can be transmitted separately to the first ECU 31 via the signal transmission unit 33. Thus, both the first ECU 31 and the second ECU 32 can distinguishably acquire the output signals of the first to fourth sensors 21 to 24.

[0038] The first ECU 31 and the second ECU 32 are configured to handle malfunctions of the first to fourth sensors 21 to 24, or open circuits or short circuits in the first to fourth signal lines 51 to 54. Specifically, when an output signal indicating an abnormal value exists among the output signals of the first to fourth sensors 21 to 24, the first ECU 31 and the second ECU 32 compare the output signals of the first to fourth sensors 21 to 24 to determine the output signal indicating the abnormal value. For example, the first ECU 31 and the second ECU 32 calculate the difference between the output signals of the first to fourth sensors 21 to 24, and if the difference (i.e., the check value) is greater than 0 or a predetermined threshold, it is set as an output signal indicating an abnormal value. Furthermore, the first ECU 31 and the second ECU 32 detect the operation amount of the brake pedal 12 based on multiple normal output signals other than the output signal indicating the abnormal value, and perform drive control on the brake circuit 40.

[0039] As the braking circuit 40, for example, it can adopt the following structure: the hydraulic pressure of the brake fluid is increased by the operation of a hydraulic pump (not shown), thereby driving the wheel cylinders 41-44 disposed on each wheel. Furthermore, the wheel cylinders 41-44 disposed on each wheel drive the brake pads disposed on each wheel. The brake pads make frictional contact with the corresponding brake discs to brake each wheel, thereby decelerating the vehicle.

[0040] In addition, the braking circuit 40 can also perform normal control, ABS control, and VSC control based on control signals from the first ECU 31 and the second ECU 32. ABS is short for Anti-lock Braking System, and VSC is short for Vehicle Stability Control.

[0041] Furthermore, the brake circuit 40 is not limited to the structure described above, which uses a hydraulic pump to drive the brake fluid flowing in the brake circuit 40 to generate hydraulic pressure. For example, it can also be configured to use an electric actuator to drive the brake pad.

[0042] Next, refer to Figure 2 and Figure 3 The brake pedal device 10 will be described. Additionally, Figure 2 and Figure 3 The recorded coordinates represent the up-down, forward-backward, and left-right directions when the brake pedal device 10 is mounted on the vehicle.

[0043] like Figure 2 and Figure 3 As shown, the brake pedal device 10 includes a housing 11, a base plate 13, a shaft 14, a brake pedal 12, and a position detection device 20. Furthermore, the housing 11 and the base plate 13 are examples of "fixed structures attached to the vehicle".

[0044] The housing 11 is a component that holds or covers the shaft 14, the position detection device 20, and a reaction force generating mechanism (not shown). The housing 11 has a housing body 111 and a housing cover 112. A space for arranging the position detection device 20 and the reaction force generating mechanism is provided inside the housing body 111. Additionally, a shaft support portion 15 is provided in the housing body 111 to support the shaft 14 so that it can rotate. The housing cover 112 is provided on the side of the housing body 111 and closes the side opening of the space formed inside the housing body 111.

[0045] The floor plate 13 extends continuously from the front side of the vehicle housing 11 to the rear side. The floor plate 13 is made of a material with higher strength than the housing 11, such as metal. The floor plate 13 is fixed to the vehicle floor 2 or front bulkhead by bolts 131 or the like. The housing 11 is fixed relative to this floor plate 13. That is, the housing 11 is fixed to the vehicle body via the floor plate 13. The floor plate 13 serves to increase the rigidity of the housing 11.

[0046] like Figure 3 As shown, the shaft 14 is rotatably or oscillatingly supported on a shaft support portion 15 provided in the housing body 111. Specifically, a cylindrical bearing 16 for supporting the shaft 14 is installed in the shaft support portion 15 provided in the housing body 111, and the shaft 14 is supported by this bearing 16. Therefore, the shaft 14 can oscillate about the center of the shaft support portion 15 (i.e., the center of the bearing 16) as its axis CL.

[0047] like Figure 2 and Figure 3As shown, the shaft 14 is formed, for example, by repeatedly bending a cylindrical metal, and has a shaft portion 141, a fixing portion 142, and a connecting portion 143. The shaft portion 141 extends parallel to the centerline of the shaft support portion 15 (i.e., the axis CL of the shaft 14), and the shaft portion 141 is disposed on the shaft support portion 15. The fixing portion 142 is a portion fixed to the brake pedal 12. The fixing portion 142 is fixed to a fixing member 121 provided on the side of the brake pedal 12 opposite to the surface that bears the pedal force from the driver (hereinafter referred to as the "back side of the brake pedal 12"). The connecting portion 143 is a portion that connects the shaft portion 141 and the fixing portion 142. By having the shaft portion 141, the fixing portion 142, and the connecting portion 143, the axis CL of the shaft 14 is disposed in a separated position from the brake pedal 12, and the position detection device 20 can be easily installed in the area around the axis CL.

[0048] The brake pedal 12 is formed into a plate shape, for example, by means of metal or resin, and is inclined relative to the floor 2. Specifically, the brake pedal 12 is inclined such that its upper end faces the front of the vehicle and its lower end faces the rear of the vehicle. Furthermore, a thick-walled portion 122 is provided on the upper part of the brake pedal 12 as a part for the driver to press. The thick-walled portion 122 is positioned above the axle CL in the vertical direction when the vehicle is mounted.

[0049] As described above, the back of the brake pedal 12 is fixed to the fixing part 142 of the shaft 14 by a fixing member 121. Therefore, the brake pedal 12 swings around the same axis CL as the shaft 14. That is, the axis CL of the brake pedal 12 is the same as the axis CL of the shaft 14. The brake pedal 12 swings around the axis CL in the forward and reverse rotation directions within a specified angle range according to the increase and decrease of the driver's pedal force.

[0050] Although not shown in the diagram, a reaction force generating mechanism is provided within the housing 11 to generate a reaction force relative to the force applied by the driver to the brake pedal 12. The reaction force generating mechanism can be composed of one or more elastic members or actuators. In this embodiment, the brake pedal 12 is configured not to be mechanically connected to the master cylinder provided in the brake circuit 40. In this configuration, by providing the reaction force generating mechanism in the brake pedal device 10, the same reaction force as in the case where the brake pedal 12 is mechanically connected to the master cylinder (i.e., the case where a reaction force is generated based on the hydraulic pressure of the master cylinder) can be obtained.

[0051] In this embodiment, the brake pedal device 10 is configured such that the brake pedal 12 and the shaft 14 swing around the same axis CL. Therefore, the swing angle of the brake pedal 12, which is depressed by the driver to control the vehicle, is the same as the swing angle of the shaft 14. The swing angle of the brake pedal 12 and the shaft 14 is directly detected by the position detection device 20 provided on and around the axis CL of the shaft 14.

[0052] like Figure 3 and Figure 4 As shown, the position detection device 20 of this embodiment is configured as a magnet-type rotation angle sensor having a cylindrical magnetic circuit section 60 fixed at the end of the shaft 14 and a magnetic detection section 70 disposed on the radially inner side of the cylindrical magnetic circuit section 60.

[0053] The magnetic circuit section 60 is formed into a cylindrical shape by two permanent magnets 61 and 62 and two arc-shaped magnetic yokes 63 and 64, and is arranged around the axis CL of the shaft 14. The magnetic circuit section 60 constitutes a closed magnetic circuit. In addition, a closed magnetic circuit refers to a circuit in which the permanent magnets 61 and 62 are in contact with the magnetic yokes 63 and 64 and the path of magnetic flux flow is closed.

[0054] Two permanent magnets 61 and 62 are arranged radially on one side and the other side, separated by an axis CL. In the following description, the magnet arranged radially on one side of the two permanent magnets 61 and 62 separated by the axis CL is referred to as the first magnet 61, and the magnet arranged radially on the other side is referred to as the second magnet 62. In addition, one of the two magnetic yokes 63 and 64 is referred to as the first magnetic yoke 63, and the other magnetic yoke is referred to as the second magnetic yoke 64.

[0055] One circumferential end of the first magnetic yoke 63 is connected to the N pole of the first magnet 61, and the other circumferential end is connected to the N pole of the second magnet 62. One circumferential end of the second magnetic yoke 64 is connected to the S pole of the first magnet 61, and the other circumferential end is connected to the S pole of the second magnet 62. Therefore, as... Figure 4 As indicated by the dashed arrow M, a magnetic field is formed in the region radially inner side of the magnetic circuit section 60, in which magnetic flux flies from the first yoke 63 toward the second yoke 64 in a direction intersecting the axis CL.

[0056] The magnetic circuit section 60 is inlaid and formed inside the resin section 65. The resin section 65 is fixed to one end of the shaft 14 by bolts 66 or the like. In this state, the center of the magnetic circuit section 60 is aligned with the axis CL of the shaft 14. Furthermore, the magnetic circuit section 60 and the shaft 14 oscillate together around the axis CL of the shaft 14. When the magnetic circuit section 60 and the shaft 14 oscillate together around the axis CL, the orientation of the magnetic field formed in the radially inner region of the magnetic circuit section 60 changes. A magnetic detection section 70 is provided in the radially inner region of the magnetic circuit section 60.

[0057] The magnetic detection unit 70 includes first to fourth sensors 21 to 24, which are integrally disposed in the resin constituting the sensor holding unit 71 by inlay molding. The sensor holding unit 71 is fixed to the housing body 111. Therefore, the sensor holding unit 71, like the housing 11 and the base plate 13, is an example of a "fixed body fixed to the vehicle". The positioning of the sensor holding unit 71 and the housing 11 is achieved by fitting a protrusion 72 provided on the outer periphery of the sensor holding unit 71 into the inner wall surface 113 of the opening provided in the housing 11. In this state, it is possible to prevent the position of the magnetic detection unit 70 provided in the sensor holding unit 71 from shifting from the axis CL of the shaft 14.

[0058] The first to fourth sensors 21 to 24 constituting the magnetic detection unit 70 are four rotation angle sensors, each having a magnetoresistive element (hereinafter referred to as "MR element") or a Hall element that outputs a signal corresponding to the magnetic field of the magnetic circuit unit 60. Furthermore, the MR element is an element whose resistance value changes according to the angle of the magnetic field in the horizontal direction relative to the magnetic sensing surface. The Hall element is an element that outputs a Hall voltage corresponding to the strength of the magnetic field in the vertical direction relative to the magnetic sensing surface.

[0059] When the driver depresses the brake pedal 12, the brake pedal 12, shaft 14, and magnetic circuit section 60 all oscillate around the axis CL. The first to fourth sensors 21 to 24 constituting the magnetic detection section 70 output signals corresponding to the oscillation angle of the magnetic circuit section 60. The oscillation angle of the magnetic circuit section 60 is the same as the oscillation angle of the brake pedal 12 and shaft 14. Therefore, the first to fourth sensors 21 to 24 output signals corresponding to the angles at which the brake pedal 12 and shaft 14 oscillate around the predetermined axis CL, respectively, as the operating amount of the brake pedal 12.

[0060] Figure 5 It is a graph showing the characteristics of the output signals of the first to fourth sensors 21 to 24 under a specified ambient temperature. Figure 5 The horizontal axis of the graph represents the amount of brake pedal 12 operation (specifically, angle or travel), and the vertical axis represents the magnitude of the output signals (specifically, output voltages) of the first to fourth sensors 21 to 24. Figure 5 In the diagram, the line labels 21S to 24S represent the output characteristics of the first to fourth sensors 21 to 24 respectively.

[0061] like Figure 5As shown in the graph, the rates of change of the output voltage of the first to fourth sensors 21 to 24 are different in response to changes in the amount of brake pedal operation 12. On the other hand, the first ECU 31 and the second ECU 32, which receive the output signals from the first to fourth sensors 21 to 24, store the relationship between the amount of brake pedal operation and the output signals of the first to fourth sensors 21 to 24. For example, as... Figure 5 As shown, regarding the brake pedal operation amount θ1, the stored information includes the output signal of the first sensor 21 as V1, the output signal of the second sensor 22 as V2, the output signal of the third sensor 23 as V3, and the output signal of the fourth sensor 24 as V4, etc. That is, the brake pedal operation amount corresponds to the output value of each sensor signal.

[0062] There are various methods for determining the output signal that represents outliers.

[0063] For example, by calculating and comparing the output differences of the first to fourth sensors 21 to 24, and using a threshold as a benchmark, normal and abnormal conditions can be detected. Therefore, even if external interference causes changes in the sensor signals, accurate sensor signal determination can be performed. Furthermore, the correct sensor signals can be used for braking control.

[0064] Specifically, when comparing the output of the first sensor 21 with the output of the second sensor 22, the following [Equation 1] is used to... Figure 5 In the graph, if the line of symbol 21S overlaps with the line of symbol 22S, and its value is greater than 0 or a specified threshold, it is considered abnormal.

[0065] (Output voltage of first sensor - intercept of first sensor) - slope of first sensor / slope of second sensor (output voltage of second sensor - intercept of second sensor)

[0066] ...[Equation 1]

[0067] Furthermore, regarding the first to fourth sensors 21 to 24, when calculating the value obtained by comparing the output difference of the two sensors other than the first and second sensors 21 and 22, the same idea as described above is also adopted.

[0068] Alternatively, as another method, the relationship between the output signals of the first to fourth sensors 21 to 24 and the brake pedal operation amount can be stored in the first ECU 31 and the second ECU 32 as described above. Based on this information, the first ECU 31 and the second ECU 32 derive four brake pedal operation amounts corresponding to the output signals of the first to fourth sensors 21 to 24, respectively. Furthermore, the output signal representing the operation amount different from the same operation amount derived by the largest amount among these four brake pedal operation amounts is determined as the output signal representing an outlier. Thus, for the signals of the four sensors 21 to 24, up to two outliers can be determined using the majority rule.

[0069] After determining the output signal indicating an abnormal value, the first ECU 31 and the second ECU 32 detect the operation amount of the brake pedal 12 based on multiple normal output signals other than the output signal indicating an abnormal value, and perform drive control on the brake circuit 40 to execute vehicle braking.

[0070] The braking system 1 of the first embodiment described above has the following effects.

[0071] (1) In the first embodiment, the output signals of the first sensor 21 and the second sensor 22 of the position detection device 20 can be transmitted separately from the first ECU 31 to the second ECU 32 via the signal transmission unit 33. Furthermore, the output signals of the third sensor 23 and the fourth sensor 24 can be transmitted separately from the second ECU 32 to the first ECU 31 via the signal transmission unit 33. Thus, the first ECU 31 and the second ECU 32 can separately acquire the output signals of the first to fourth sensors 21 to 24. Therefore, the first ECU 31 and the second ECU 32 can determine the output signal representing an abnormal value by comparing the output signals of the first to fourth sensors 21 to 24. Therefore, the first ECU 31 and the second ECU 32 can detect an accurate operating quantity based on multiple normal output signals other than abnormal values, thereby performing drive control on the braking circuit 40. As a result, the braking system 1 can improve the safety of vehicle braking control in the face of malfunctions of the first to fourth sensors 21 to 24.

[0072] Furthermore, when at least two of the output signals from the first to fourth sensors 21 to 24 indicate the same operating amount, the first ECU 31 and the second ECU 32 can determine the output signals from the two sensors indicating different operating amounts as output signals indicating abnormal values. Therefore, even in the face of multiple sensor failures, the braking system 1 can detect the accurate operating amount of the brake pedal 12 based on multiple normal output signals other than abnormal values, thereby performing drive control on the brake circuit 40.

[0073] (2) In the first embodiment, the first sensor 21 is connected to the first ECU 31 via a first signal line 51. The second sensor 22 is connected to the first ECU 31 via a second signal line 52. The third sensor 23 is connected to the second ECU 32 via a third signal line 53. The fourth sensor 24 is connected to the second ECU 32 via a fourth signal line 54.

[0074] Accordingly, by connecting multiple ECUs to multiple sensors 21-24 via wires, information transmission between the multiple ECUs and the multiple sensors 21-24 can be stably achieved.

[0075] (3) In the first embodiment, the first ECU 31 and the second ECU 32 determine the output signal representing an abnormal value as follows: that is, the first ECU 31 and the second ECU 32 determine the output signal representing an operational quantity that is different from the multiple output signals representing the same operational quantity as the output signal representing an abnormal value, wherein the same operational quantity refers to the operational quantity derived by the largest amount among the multiple operational quantities derived from the output signals of the first to fourth sensors 21 to 24.

[0076] Accordingly, it is possible to determine the output signal representing an abnormal value by taking the multiple output signals of the same operational quantity derived from the output signals of the first to fourth sensors 21 to 24 as the correct output signal.

[0077] (4) In the first embodiment, the first to fourth sensors 21 to 24 of the position detection device 20 are all rotation angle sensors that output signals corresponding to the angle of the brake pedal 12 swinging around a predetermined axis CL.

[0078] Accordingly, four rotation angle sensors are set by means of the pivot CL of the brake pedal 12, which simplifies the structure and reduces the number of parts, assembly time and cost.

[0079] (5) In the first embodiment, the position detection device 20 is a magnet-type rotation angle sensor having a magnetic circuit section 60 that forms a magnetic field and a magnetic detection section 70 that serves as four rotation angle sensors for detecting the magnetic field of the magnetic circuit section 60.

[0080] Accordingly, the magnetic circuit section 60 that generates the magnetic field detected by the magnetic detection section 70 (e.g., a Hall element or an MR element) can be made into a common component (i.e., one magnetic circuit section 60). Therefore, the specifications of the magnet-type rotation angle sensor with four rotation angle sensors can be miniaturized, and the number of parts, assembly time, and cost can be reduced.

[0081] (6) The braking system 1 of the first embodiment is configured as a completely drive-by braking system in which the components of the braking circuit 40 are not mechanically connected to the brake pedal 12.

[0082] Therefore, in a fully brake-by-wire system, the safety of vehicle braking control can be improved in the event of a failure in the first to fourth sensors 21 to 24.

[0083] (Second Implementation)

[0084] The second embodiment will be described. The second embodiment differs from the first embodiment by changing the structure of the position detection device 20, but is otherwise the same as the first embodiment. Therefore, only the parts that are different from the first embodiment will be described.

[0085] like Figures 6-8 As shown, the position detection device 20 of the second embodiment includes: a magnet-type rotation angle sensor having a magnetic circuit section 60 and a magnetic detection section 70; and an inductive sensor having a target 80, a coil 90 and a transceiver circuit 91.

[0086] In the second embodiment, the magnetic detection unit 70 of the magnet-type rotation angle sensor is composed of a first sensor 21 and a second sensor 22. That is, both the first sensor 21 and the second sensor 22 are rotation angle sensors, and output a signal corresponding to the angle at which the brake pedal 12 swings around a predetermined axis CL as the operating amount of the brake pedal 12.

[0087] Furthermore, in the second embodiment, the transceiver circuit 91 of the inductive sensor is composed of a third sensor 23 and a fourth sensor 24. That is, both the third sensor 23 and the fourth sensor 24 are travel sensors, and output signals corresponding to the travel distance of the brake pedal 12 or the component that moves together with the brake pedal 12 as the operation amount of the brake pedal 12.

[0088] The following provides specific examples of magnetic rotation angle sensors and inductive sensors.

[0089] The magnetic circuit section 60 of the magnet-type rotation angle sensor, like that of the first embodiment, is formed into a closed magnetic circuit by two permanent magnets 61 and 62 and two arc-shaped magnetic yokes 63 and 64. A magnetic detection section 70 is provided in the radially inner region of the magnetic circuit section 60.

[0090] The first sensor 21 and the second sensor 22 constituting the magnetic detection unit 70 are integrally disposed in the resin constituting the sensor holding unit 71 by inlay molding. Both the first sensor 21 and the second sensor 22 are rotation angle sensors such as MR elements or Hall elements that output signals corresponding to the magnetic field of the magnetic circuit unit 60.

[0091] The target 80 constituting the inductive sensor is positioned radially inward from the inner circumferential surface of the cylindrical magnetic circuit section 60. This allows for radial miniaturization of the position detection device 20. Furthermore, the radially inward region from the inner circumferential surface of the magnetic circuit section 60 also includes a position offset relative to the axial direction of the magnetic circuit section 60. Figure 6 As shown, in the second embodiment, the target 80 and the magnetic circuit portion 60 are configured such that at least a portion of the target 80 overlaps radially with a portion of the magnetic circuit portion 60 when viewed radially from the magnetic circuit portion 60. Figure 6 In the diagram, the area where the target 80 and the magnetic circuit section 60 overlap radially when viewed radially from the magnetic circuit section 60 is indicated by a double-headed arrow OL. This allows for miniaturization of the position detection device 20 in the axial direction. Furthermore, it is not limited to... Figure 6 As shown, the target 80 and the magnetic circuit section 60 can also be non-overlapping in the radial direction.

[0092] The target 80 is formed of a conductive material such as metal and is positioned around the axis CL. For example... Figure 7 As shown, the target 80 has, for example, three outer arcuate portions 811-813, three inner arcuate portions 821-823, and six connecting portions 831-836 connecting the outer arcuate portions 811-813 to the inner arcuate portions 821-823. The three outer arcuate portions 811-813 are arranged at approximately equal intervals in the circumferential direction. The three inner arcuate portions 821-823 are arranged at approximately equal intervals in the circumferential direction, radially inward of the outer arcuate portions 811-813. The outer arcuate portions 811-813 and the inner arcuate portions 821-823 that are adjacent in the circumferential direction are positioned at a position that is offset in the circumferential direction (i.e., they do not overlap radially except at the circumferential ends of the outer arcuate portions 811-813 and the inner arcuate portions 821-823). The six connecting portions 831 to 836 extend radially to connect the circumferential ends of the outer arc portions 811 to 813 with the circumferential ends of the inner arc portions 821 to 823.

[0093] In addition, not limited to Figure 7 As shown, the shape and size of the target 80 can be arbitrarily set.

[0094] The target 80 and the magnetic circuit portion 60 are embedded in the inner side of the resin portion 65. Thus, the magnetic circuit portion 60 and the target 80 are sub-components, and positional misalignment between the magnetic circuit portion 60 and the target 80 is prevented. A recess 67 is provided in the center of the resin portion 65, recessed from the sensor holding portion 71 side toward the shaft 14 side. A magnetic detection portion 70 (i.e., the first sensor 21 and the second sensor 22) constituting part of the magnet-type rotation angle sensor is provided inside this recess 67.

[0095] The resin part 65 is fixed to one end of the shaft 14. That is, the magnetic circuit part 60 and the target 80, which are assembled by the component, are fixed to one end of the shaft 14 via the resin part 65. In this state, the center of the magnetic circuit part 60 and the center of the target 80 are aligned with the axis CL of the shaft 14. Furthermore, the magnetic circuit part 60 and the target 80 oscillate together with the shaft 14 around the axis CL of the shaft 14.

[0096] On the other hand, a magnetic detection unit 70, which constitutes part of a magnet-type rotation angle sensor, and a circuit board 92, which is equipped with a coil 90, which constitutes part of an inductive sensor, and a transceiver circuit 91, are fixed to the sensor holding part 71. That is, the coil 90 and the transceiver circuit 91 are fixed to the sensor holding part 71 while being mounted on the circuit board 92.

[0097] The circuit board 92 is fixed to the surface of the sensor holding part 71 facing the magnetic circuit part 60. A hole 93 is provided in the center of the circuit board 92 for the magnetic detection part 70 to be inserted. The magnetic detection part 70 passes through the hole 93 of the circuit board 92 and is disposed in the region radially inward of the magnetic circuit part 60 (specifically, the region inside the recess 67 of the resin part 65).

[0098] like Figure 8 As shown, a coil 90 and a transceiver circuit 91 are mounted on the circuit board 92. The coil 90 is positioned opposite the target 80 in the axial direction. Figure 8 In the diagram, the area on the circuit board 92 where the coil 90 is mounted is indicated by a cross-shaded line. Additionally, in... Figure 8 The diagram shows an example of the shape of a coil 90 mounted on a circuit board 92, but the shape of the coil 90 is not limited to this and can be of various shapes. For example, the shape of the coil 90 can be a sine curve with the circumferential direction as the horizontal axis. The coil 90 includes a patterned transmitting coil Tx and two patterned receiving coils Rx-sin and Rx-cos.

[0099] The third sensor 23 and the fourth sensor 24 constituting the transceiver circuit 91 are configured by being assembled onto an integrated circuit (i.e., an IC) mounted on a circuit board 92. The transceiver circuit 91 applies an alternating current to the coil 90 and detects the position of the target 80 based on the physical principle of eddy currents generated in the target 80 moving on the coil pattern, according to the change in inductance of the coil 90. That is, the third sensor 23 and the fourth sensor 24 constituting the transceiver circuit 91 can be considered as travel sensors that detect the moving distance of the target 80.

[0100] In the second embodiment, a structure is configured to obtain two outputs (2 outputs) from the transceiver circuit 91 (i.e., the third sensor 23 and the fourth sensor 24). Specifically, for example, a structure that performs 2 outputs can be configured using a patterned transmitting coil Tx, two patterned receiving coils Rx-sin and Rx-cos (i.e., Rx-sin is one pattern and Rx-cos is another pattern) and the transceiver circuit 91. Furthermore, the transceiver circuit 91 is configured to include the third sensor 23 and the fourth sensor 24. In this case, two signals Tx1 and Tx2 can be applied to the patterned transmitting coil Tx, and the signals are transmitted by a transmitter within the transceiver circuit 91.

[0101] Alternatively, a dual-output configuration can be achieved using two patterned transmitting coils Tx, two patterned receiving coils Rx-sin and Rx-cos (i.e., Rx-sin represents one pattern, and Rx-cos represents the other), and a transceiver circuit 91. Furthermore, similarly to the above, the transceiver circuit 91 includes a third sensor 23 and a fourth sensor 24. In this case, two signals Tx1 and Tx2 can be applied to the two patterned transmitting coils Tx respectively, and the signals are transmitted by the two transmitters within the transceiver circuit 91.

[0102] In addition, the transceiver circuit 91 (i.e., the third sensor 23 and the fourth sensor 24) can be configured as a single package or as two packages.

[0103] In addition to the effects of the braking system 1 described in the first embodiment, the braking system 1 of the second embodiment described above also has the following effects.

[0104] (1) In the second embodiment, the first sensor 21 and the second sensor 22 of the position detection device 20 are rotation angle sensors, and the third sensor 23 and the fourth sensor 24 are travel sensors.

[0105] Accordingly, by using different types of sensors, the simultaneous failure of all four sensors 21 to 24 in the face of specified external interference factors can be prevented.

[0106] One consideration is to use a force sensor, for example, instead of a rotation angle sensor or a stroke sensor, to detect the amount of brake pedal 12 operation. However, if a force sensor is used to detect the amount of brake pedal 12 operation, problems exist as follows (A), (B), and (C).

[0107] (A) Typically, force sensors have a dead zone, which results in insufficient accuracy of the output signal.

[0108] (B) The rotation angle sensor causes its output voltage to change linearly in response to changes in the amount of brake pedal 12 operation. In contrast, the force sensor's output exhibits hysteresis. That is, the force sensor has a problem where the output value differs when the amount of brake pedal 12 operation changes from small to large versus when it changes from large to small.

[0109] (C) Based on (A) and (B) above, when a force sensor is used to detect the amount of operation of the brake pedal 12, there is a problem that it is difficult to compare the output signals of the four force sensors to determine the signal representing the abnormal value.

[0110] In contrast, the braking system 1 of the second embodiment does not produce the problems described in (A), (B), and (C) above because the first to fourth sensors 21 to 24 are rotation angle sensors and stroke sensors. Therefore, in this embodiment, the output signal representing an abnormal value can be determined by comparing the four output signals generated by the rotation angle sensor and the stroke sensor.

[0111] (2) In the second embodiment, the position detection device 20 includes a magnetic rotation angle sensor and an inductive sensor. The magnetic rotation angle sensor has a magnetic circuit section 60 and a magnetic detection section 70 that serves as two rotation angle sensors (i.e., a first sensor 21 and a second sensor 22). On the other hand, the inductive sensor has a target 80, a coil 90 (i.e., a transmitting coil and a receiving coil), and a transceiver circuit 91 that serves as two travel sensors (i.e., a third sensor 23 and a fourth sensor 24). Accordingly, the position detection device 20 provides two types of sensors, and by arranging the two types of sensors together around the axis CL of the shaft 14, it is possible to miniaturize both the radial and axial dimensions.

[0112] (Third Implementation)

[0113] The third embodiment will be described. The third embodiment differs from the first embodiment by changing the structure of the signal lines connecting sensors 21-24 to the ECU. Everything else is the same as the first embodiment, so only the parts that are different from the first embodiment will be described.

[0114] like Figure 9 As shown, in the third embodiment, the position detection device 20 provided on the brake pedal device 10 also has first to fourth sensors 21 to 24. Furthermore, the first to fourth sensors 21 to 24 can be entirely composed of rotation angle sensors, as in the first embodiment, or they can be composed of two rotation angle sensors and two stroke sensors, as in the second embodiment.

[0115] In the third embodiment, the first sensor 21 is electrically connected to the first ECU 31 via a first signal line 51, and the third sensor 23 is electrically connected to the first ECU 31 via a third signal line 53. Therefore, the output signals of the first sensor 21 and the third sensor 23 can be input to the first ECU 31 separately.

[0116] Furthermore, the second sensor 22 is electrically connected to the second ECU 32 via the second signal line 52, and the fourth sensor 24 is electrically connected to the second ECU 32 via the fourth signal line 54. Therefore, the output signals of the second sensor 22 and the fourth sensor 24 can be input to the second ECU 32 separately.

[0117] In the third embodiment, similarly to the first and second embodiments, the first ECU 31 and the second ECU 32 are connected via a signal transmission unit 33, enabling them to exchange information. Therefore, the output signals of the first sensor 21 and the third sensor 23 input to the first ECU 31 can be separately transmitted to the second ECU 32 via the signal transmission unit 33. Similarly, the output signals of the second sensor 22 and the fourth sensor 24 input to the second ECU 32 can be separately transmitted to the first ECU 31 via the signal transmission unit 33. Thus, both the first ECU 31 and the second ECU 32 can separately acquire the output signals of the first to fourth sensors 21 to 24.

[0118] When an output signal indicating an abnormal value exists among the output signals of the first to fourth sensors 21 to 24, the first ECU 31 and the second ECU 32 can determine the output signal indicating an abnormal value by comparing the output signals of the first to fourth sensors 21 to 24. Furthermore, the first ECU 31 and the second ECU 32 detect the amount of brake pedal operation 12 based on multiple output signals other than the output signal indicating the abnormal value, and perform drive control on the brake circuit 40. Therefore, the braking system 1 of the third embodiment described above also achieves the same effect as the braking system 1 described in the first and second embodiments.

[0119] (Other implementation methods)

[0120] (1) In the above embodiments, the position detection device 20 is described as having first to fourth sensors 21 to 24, but it is not limited thereto. The position detection device 20 may also have four or more sensors. In other words, the position detection device 20 may also have at least four sensors.

[0121] (2) In the first to third embodiments described above, it was described that the output signals of two sensors were input to the first ECU 31 and the output signals of two other sensors were input to the second ECU 32, but it is not limited to this. It is also possible to input the output signals of two or more sensors to the first ECU 31, and it is also possible to input the output signals of two or more sensors to the second ECU 32.

[0122] (3) In the above embodiments, the position detection device 20 is described as being provided on and around the axis CL of the shaft 14, but it is not limited thereto. The position detection device 20 may also be a device for detecting the amount of movement or the swing angle of the brake pedal 12 or various components (e.g., reaction force generating mechanism and its associated components) that move together with the brake pedal 12.

[0123] (4) In the second embodiment described above, the coil 90 and the target 80 constituting the inductive sensor are arranged around the axis CL within a range of 360° (i.e., a range covering the entire circumference), but are not limited thereto. For example, the coil 90 and the target 80 constituting the inductive sensor may also be arranged within a predetermined angular range smaller than 360° (i.e., a fan-shaped or arc-shaped range).

[0124] (5) In the above embodiments, the brake pedal device 10 is described as an organ-type pedal device, but it is not limited to this and may also be a suspended type. In addition, a suspended pedal device refers to a pedal device in which the part of the brake pedal 12 for the driver to step on is positioned below the pivot point CL in the vertical direction when the vehicle is mounted.

[0125] (6) In the above embodiments, the braking system 1 is described as a completely brake-by-wire system in which the components of the brake circuit 40 are not mechanically connected to the brake pedal 12. However, it is not limited to this and can also be a conventional brake-by-wire system. In addition, a conventional brake-by-wire system refers to a brake-by-wire system in which the ECU drives and controls the brake circuit 40 based on the output signal of the position detection device 20, and the master cylinder of the brake circuit 40 is mechanically connected to the brake pedal 12.

[0126] (7) In the above embodiments, the braking system 1 is described as having a first ECU 31 and a second ECU 32, but it is not limited thereto. The braking system 1 may also have three or more ECUs.

[0127] This disclosure is not limited to the embodiments described above, and appropriate modifications are permissible. Furthermore, the embodiments described above are not unrelated to each other; they can be appropriately combined except in cases where they are explicitly impossible to combine. Additionally, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential elements, except where they are specifically stated to be necessary or are explicitly considered necessary in principle. Furthermore, in each of the above embodiments, when referring to the number, value, quantity, range, etc., of the constituent elements of the embodiment, the number is not limited to that specific number, except where it is specifically stated to be necessary or is explicitly limited to a specific number in principle. Furthermore, in each of the above embodiments, when referring to the shape, positional relationship, etc., of the constituent elements, the shape, positional relationship, etc., is not limited to that shape, positional relationship, etc., except where it is specifically stated or is limited to a specific shape or positional relationship in principle.

[0128] The control unit and method described in this disclosure can be implemented using a dedicated computer provided by means of a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and method described in this disclosure can also be implemented using a dedicated computer provided by means of a processor configured using one or more dedicated hardware logic circuits. Alternatively, the control unit and method described in this disclosure can also be implemented using one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program can also be stored as instructions executable by the computer in a computer-readable, non-transitory tangible storage medium.

Claims

1. A braking system that drives and controls a braking circuit for braking a vehicle, characterized in that, have: A brake pedal device having a brake pedal configured to swing about a predetermined axis relative to a fixed body fixed to the vehicle. A position detection device having at least four sensors that output signals corresponding to the amount of operation of the brake pedal by the driver. A first electronic control device, wherein the output signals of at least two of the at least four sensors are input to the first electronic control device in a manner that distinguishes them from each other; The second electronic control device is provided in which the output signals of at least two of the at least four sensors, excluding the sensor that inputs an output signal to the first electronic control device, are input to the second electronic control device in a way that makes them distinct from each other. as well as The signal transmission unit is capable of separately transmitting the output signals of at least two sensors input to one of the electronic control devices (the first and the second) to the other electronic control device. The first electronic control device and the second electronic control device are configured to determine an output signal representing an abnormal value based on the output signals of the at least four sensors, detect the amount of operation of the brake pedal based on multiple output signals other than the abnormal value, and perform drive control on the brake circuit.

2. The braking system according to claim 1, characterized in that, It also has: The first signal line and the second signal line electrically connecting at least two of the at least four sensors to the first electronic control device, respectively; and The third signal line and the fourth signal line are respectively electrically connected to the second electronic control device by at least two of the at least four sensors other than the sensor that inputs a signal to the first electronic control device.

3. The braking system according to claim 1 or 2, characterized in that, The first electronic control device and the second electronic control device determine the output signal representing the outlier as the output signal representing the outlier, which represents an operation quantity that is different from the same operation quantity derived by the maximum amount, wherein the same operation quantity derived by the maximum amount refers to the same operation quantity derived by the maximum amount among a plurality of operation quantities derived from the output signals of the at least four sensors.

4. The braking system according to claim 1 or 2, characterized in that, The position detection device has at least four sensors, all of which are rotation angle sensors that output signals corresponding to the angle at which the brake pedal swings around a predetermined axis, serving as the operation amount of the brake pedal.

5. The braking system according to claim 4, characterized in that, The position detection device comprises at least one magnetic circuit portion that forms a magnetic field that flies along a direction intersecting the axis of the swing of the brake pedal, and a magnetic detection portion that serves as the at least four rotation angle sensors for detecting the magnetic field of the magnetic circuit portion.

6. The braking system according to claim 1 or 2, characterized in that, At least two of the at least four sensors in the position detection device are rotation angle sensors that output signals corresponding to the angle at which the brake pedal swings around a predetermined axis, serving as the amount of brake pedal operation. Of the at least four sensors in the position detection device, at least two of the sensors other than the rotation angle sensor are stroke sensors that output signals corresponding to the distance of movement of the brake pedal or a component that moves with the brake pedal, serving as the amount of operation of the brake pedal.

7. The braking system according to claim 6, characterized in that, The position detection device includes: A magnet-type rotation angle sensor has at least one magnetic loop portion that forms a magnetic field through which magnetic flux flows in a direction intersecting the axis of the swing of the brake pedal, and a magnetic detection portion that detects the magnetic field of the magnetic loop portion as at least two of the rotation angle sensors. as well as An inductive sensor has at least one target formed of a conductor, at least one coil disposed at a position opposite to the target in the axial direction, and a transceiver circuit as at least two travel sensors for detecting the position of the target based on the change in the inductance of the coil, wherein the inductance of the coil changes according to eddy currents flowing in the target when an alternating current is applied to the coil.

8. The braking system according to claim 1 or 2, characterized in that, The braking system is configured as a complete brake-by-wire system, which is a system in which the components of the braking circuit are not mechanically connected to the brake pedal, and at least one of the first electronic control device and the second electronic control device detects the amount of brake pedal operation based on the output signals of a plurality of the sensors and performs drive control on the braking circuit.

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