signal processing device

Abstract

A signal processing device (3) that processes a sensor signal output from a sensor (6) of a brake pedal device (4) comprises a behavior determination unit (16), a filter circuit (17), and a filter constant setting unit (18). The behavior determination unit (16) determines, on the basis of the sensor signal, whether or not a bouncing behavior occurs after a pedal arm (8) rotates in the closing direction and reaches the fully closed position. The filter circuit (17) performs smoothing on the sensor signal according to a filter constant and generates a control signal for braking a vehicle, the filter circuit generating a control signal with a greater degree of smoothing of the change in the sensor signal the larger the filter constant. The filter constant setting unit (18) sets a larger filter constant when the behavior determination unit (16) determines that the bouncing behavior occurs than when the behavior determination unit (16) determines that the bouncing behavior does not occur.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2023-071628, filed on April 25, 2023, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a signal processing device used in a brake-by-wire system. [Background technology]

[0003] Conventionally, there are known brake-by-wire systems in which an electronic control unit controls vehicle braking based on an electrical signal output from a brake pedal device mounted on a vehicle, and there are also known accelerator-by-wire systems in which an electronic control unit controls vehicle acceleration and deceleration based on an electrical signal output from an accelerator pedal device. Patent Document 1 describes an accelerator pedal device used in an accelerator-by-wire system. This accelerator pedal device includes a pedal arm that rotates in response to the pedal force applied by the driver, a spring mechanism that applies a reaction force to the pedal arm against the pedal force, and two full-close stoppers that stop the pedal arm in a fully closed position. The fully closed position is a position where rotation of the pedal arm is restricted when the driver is not applying a pedal force to the pedal arm, and is referred to as a rest position in Patent Document 1. Patent Document 1 also refers to the full-close stoppers as rest stoppers. This accelerator pedal device is designed to suppress the impact noise that occurs when the pedal arm rotates forcefully due to the biasing force of the spring mechanism and hits the full-close stoppers when the driver releases their foot from the pedal arm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4374180 Summary of the Invention

[0005] However, when a driver releases his or her foot from a depressed state on the pedal arm, if the pedal arm collides with the fully closed stopper due to the biasing force of the spring mechanism with a large impact force, the pedal arm may bounce back near the fully closed position. In this case, the sensor signal output from the accelerator pedal device sensor also oscillates near the fully closed position. Therefore, if an electronic control unit controls the acceleration / deceleration of the vehicle based on the sensor signal, the vehicle may accelerate or decelerate against the driver's intention to release the accelerator, resulting in a problem of deterioration in drivability. However, Patent Document 1 does not mention this problem. The problem of deterioration in drivability due to the pedal arm's bouncing back behavior can occur not only in accelerator-by-wire systems but also in brake-by-wire systems.

[0006] Generally, the biasing force of a spring mechanism included in a brake pedal device used in a brake-by-wire system is greater than the biasing force of a spring mechanism included in an accelerator pedal device. Therefore, in a brake pedal device, when a driver releases his / her foot from a state in which the pedal arm is depressed, the impact force when the pedal arm collides with the fully closed stopper is greater in comparison with an accelerator pedal device, resulting in a greater rebound behavior of the pedal arm. In this case, the sensor signal output from the brake pedal device sensor also oscillates significantly near the fully closed position. Therefore, if an electronic control unit applies vehicle braking based on the sensor signal, the vehicle braking is performed against the driver's intention to release the brake, resulting in a problem of deterioration in drivability.

[0007] Furthermore, in a brake-by-wire system, if the electronic control unit brakes the vehicle in response to a sensor signal that vibrates due to the pedal arm's bouncing behavior, the number of unnecessary vehicle braking operations increases, which can lead to problems such as accelerated wear on brake pads, etc.

[0008] To solve these problems, it is conceivable to set a large filter constant in the filter circuit that smooths the sensor signal output from the sensor in the signal processing device used in the brake-by-wire system. However, if the filter constant is set to a large value, the response of the vehicle braking will be delayed when the driver depresses and releases the pedal arm, which will deteriorate drivability.

[0009] Another possible solution to prevent the pedal arm from bouncing back is to increase the size of the fully closed stopper to physically absorb the impact force of the pedal arm. However, increasing the size of the fully closed stopper would increase the size of the brake pedal device, raising concerns about increased manufacturing costs.

[0010] An object of the present disclosure is to improve drivability at low cost without increasing the size of a brake pedal device in a signal processing device used in a brake-by-wire system.

[0011] According to one aspect of the present disclosure, a signal processing device is used in a brake-by-wire system and processes a sensor signal output from a sensor of a brake pedal device. The brake pedal device includes a support, a pedal arm, a spring mechanism, a full-close stopper, and a sensor. The support is attached to the vehicle. The pedal arm is rotatable about a predetermined axis relative to the support, rotating in the open direction when the driver's pedal force increases and in the close direction when the driver's pedal force decreases or is released. The spring mechanism applies a biasing force to the pedal arm that acts as a counterforce against the driver's pedal force. The full-close stopper stops the pedal arm at a full-close position where rotation of the pedal arm in the close direction is restricted when the driver's pedal force is not applied to the pedal arm. The sensor outputs a sensor signal corresponding to the angle or stroke of the pedal arm. The signal processing device that processes the sensor signal includes a behavior determination unit, a filter circuit, and a filter constant setting unit. The behavior determination unit determines, based on the sensor signal, whether or not a bouncing behavior will occur after the pedal arm rotates in the closing direction and reaches the fully closed position. The filter circuit performs a smoothing process on the sensor signal according to the filter constant to generate a control signal for braking the vehicle, and the larger the filter constant, the greater the smoothing degree of the change in the sensor signal that is generated. The filter constant setting unit sets the filter constant when the behavior determination unit determines that a bouncing behavior will occur to a value greater than the filter constant when the behavior determination unit determines that a bouncing behavior will not occur.

[0012] According to this, when the behavior determination unit determines that a rebound behavior will occur, the filter constant setting unit sets a large filter constant, and the filter circuit generates a control signal that greatly smooths the change in the sensor signal. Therefore, even if the driver releases his / her foot from the pedal arm and the pedal arm behaves in a rebound behavior, the electronic control unit of the brake-by-wire system immediately releases the vehicle brakes based on the control signal in which the change in the sensor signal has been greatly smoothed, thereby improving drivability.

[0013] On the other hand, when the behavior determination unit determines that the rebound behavior will not occur, the filter constant setting unit sets the filter constant to a smaller value than when the rebound behavior will occur, and the filter circuit generates a control signal that less moderates the change in the sensor signal. Therefore, when the driver performs a depressing operation and a releasing operation with their foot on the pedal arm, the electronic control unit of the brake-by-wire system performs vehicle braking with high response based on the control signal that less moderates the change in the sensor signal, thereby improving drivability.

[0014] Furthermore, according to the signal processing of this signal processing device, even if the pedal arm exhibits a bouncing behavior, the electronic control device immediately cancels the vehicle braking command, so there is no unnecessary increase in the number of vehicle braking operations, and unnecessary wear on the brake pads, etc. can be prevented.

[0015] Furthermore, with the signal processing of this signal processing device, even if the biasing force of the spring mechanism of the brake pedal device is increased, there is no need to increase the size of the full-close stopper that physically absorbs the impact force of the pedal arm, and drivability can be improved through control. Therefore, an increase in the size of the brake pedal device due to an increase in the size of the full-close stopper can be prevented, and manufacturing costs can be reduced.

[0016] According to another aspect of the present disclosure, a signal processing device is used in a brake-by-wire system and processes a sensor signal output from a sensor of a brake pedal device. The brake pedal device includes a support, a pedal arm, a spring mechanism, a full-close stopper, and a sensor. The support is attached to the vehicle. The pedal arm is rotatable about a predetermined axis relative to the support, rotating in the open direction when the driver's pedal force increases and in the close direction when the driver's pedal force decreases or is released. The spring mechanism applies a biasing force to the pedal arm that acts as a counterforce against the driver's pedal force. The full-close stopper stops the pedal arm at a full-close position where rotation of the pedal arm in the close direction is restricted when the driver's pedal force is not applied to the pedal arm. The sensor outputs a sensor signal corresponding to the angle or stroke of the pedal arm. The signal processing device that processes the sensor signal includes a behavior determination unit and a signal switching unit. The behavior determination unit determines, based on the sensor signal, whether or not a rebound behavior will occur after the pedal arm rotates in the closing direction and reaches the fully closed position. When the behavior determination unit determines that a rebound behavior will occur, the signal switching unit switches a control signal for braking the vehicle to a signal value indicating that the pedal arm is in the fully closed position (hereinafter referred to as a "fully closed signal") for a predetermined time and outputs the signal.

[0017] According to this, when the behavior determination unit determines that a rebound behavior will occur, the signal switching unit switches the control signal to a full-close signal for a predetermined time and outputs it. Therefore, even if the driver releases his / her foot from the pedal arm while it is depressed and the pedal arm behaves in a rebound behavior, the electronic control unit of the brake-by-wire system immediately releases the vehicle brake based on the full-close signal, thereby improving drivability.

[0018] On the other hand, if the behavior determination unit determines that the rebound behavior will not occur, the signal switching unit does not switch the control signal to a fully closed signal. Therefore, when the driver performs a depressing operation and a releasing operation with his / her foot on the pedal arm, the electronic control unit of the brake-by-wire system performs vehicle braking with high response based on the control signal or the sensor signal that has been normally processed, thereby improving drivability.

[0019] Furthermore, according to the signal processing of the signal processing device according to another aspect of the present disclosure, similar to one aspect of the present disclosure, there is no unnecessary increase in the number of vehicle braking operations, and unnecessary wear on brake pads, etc. can be prevented.

[0020] Furthermore, according to the signal processing of the signal processing device according to another aspect of the present disclosure, as with one aspect of the present disclosure, there is no need to increase the size of the fully closed stopper, which prevents the brake pedal device from becoming larger and reduces manufacturing costs.

[0021] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic configuration diagram of a brake-by-wire system in which a signal processing device according to a first embodiment is used. [Figure 2] 1 is a block diagram of an electronic control device incorporating a signal processing device according to a first embodiment. [Figure 3]4 is a flowchart showing a control process executed by the signal processing device according to the first embodiment. [Figure 4] 4 is a graph showing the relationship between a sensor signal and a control signal in the signal processing device according to the first embodiment. [Figure 5] 10 is a graph showing the relationship between a sensor signal and a control signal in a signal processing device of a comparative example. [Figure 6] FIG. 10 is a block diagram of an electronic control device incorporating a signal processing device according to a second embodiment. [Figure 7] FIG. 10 is a block diagram of an electronic control device incorporating a signal processing device according to a second embodiment. [Figure 8] 10 is a flowchart showing a control process executed by a signal processing device according to a second embodiment. [Figure 9] 10 is a graph showing the relationship between a sensor signal and a control signal in a signal processing device according to a second embodiment. [Figure 10] 10 is a graph showing the relationship between a sensor signal and a control signal, and the operating speed of a pedal arm in a signal processing device according to a third embodiment. [Figure 11] 10 is a graph showing the relationship between a sensor signal and a control signal, and the duration of time the pedal arm remains in the fully closed position, in a signal processing device according to a fourth embodiment. [Figure 12] 10 is a graph showing the relationship between a sensor signal and a control signal, the movement speed of a pedal arm, and the acceleration of the movement of the pedal arm in a signal processing device according to a fifth embodiment. [Figure 13] 10 is a graph showing the relationship between the angle or stroke of the pedal arm and the biasing force acting on the pedal arm from the spring mechanism in a signal processing device according to a fifth embodiment. [Figure 14] 13 is a graph showing the relationship between a sensor signal and a control signal in a signal processing device according to a sixth embodiment. [Figure 15] FIG. 13 is a schematic configuration diagram of a brake-by-wire system in which a signal processing device according to a seventh embodiment is used. [Figure 16]13 is a graph showing the relationship between a sensor signal and a control signal, and the output value of a load sensor in a signal processing device according to a seventh embodiment. [Figure 17] FIG. 13 is a schematic configuration diagram of a brake-by-wire system in which a signal processing device according to an eighth embodiment is used. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0024] (First embodiment) A first embodiment will be described with reference to the drawings. As shown in FIG. 1, in the first embodiment, a signal processing device 3 is incorporated into a part of an electronic circuit of an electronic control device 2 used in a brake-by-wire system 1 that performs vehicle braking. Hereinafter, the electronic control device 2 will be referred to as an "ECU 2." ECU stands for Electronic Control Unit. Note that the signal processing device 3 is not limited to being incorporated into the ECU 2, and may be configured as an integrated circuit such as an IC or ASIC integrated with a sensor 6 provided in a brake pedal device 4.

[0025] First, the general configuration of the brake-by-wire system 1 will be described. 1, the brake-by-wire system 1 includes a brake pedal device 4, an ECU 2, and a brake mechanism 5. The brake-by-wire system 1 is a system in which the ECU 2 controls the driving of the brake mechanism 5 based on a sensor signal output from a sensor 6 included in the brake pedal device 4, thereby braking the vehicle. In particular, the brake-by-wire system 1 in which the signal processing device 3 of the first embodiment is used is a complete brake-by-wire system in which components of the brake mechanism 5 (for example, a master cylinder) and the brake pedal device 4 are not mechanically connected.

[0026] The brake pedal device 4 includes a housing 7 as a support, a pedal arm 8, a full-close stopper 9, a spring mechanism 10, and a sensor 6. Note that FIG.

[0027] The housing 7 of the brake pedal device 4 is fixed to the vehicle with bolts or the like (not shown). Specifically, the housing 7 is fixed to the floor 22 or dash panel inside the vehicle cabin. An internal space 11 is provided inside the housing 7. The internal space 11 contains the sensor 6, the spring mechanism 10, the shaft 12, and the like. The sensor 6 is provided in a position overlapping the shaft 12 in the axial direction thereof. Therefore, the shaft 12 is provided on the far side of the paper surface of FIG. 1 relative to the sensor 6. The shaft 12 is provided rotatably relative to the housing 7 around its own axis CL.

[0028] The pedal arm 8 is formed in a generally plate-like shape and is fixed to the shaft 12 via a connecting member 13. One end of the connecting member 13 is fixed to the underside of the pedal arm 8, and the other end is fixed to the shaft 12. Therefore, the pedal arm 8 is provided to be rotatable with respect to the housing 7 around the axis CL of the shaft 12.

[0029] The brake pedal device 4 of the first embodiment is an organ-type pedal device. An organ-type pedal device is one in which all or most of the pedal tread surface 14, which is the portion of the pedal arm 8 to which the driver's pedal force is applied, is located above the rotation axis CL of the pedal arm 8 in the vertical direction when the pedal arm 8 is installed in the vehicle, i.e., above the vehicle. In an organ-type pedal device, the pedal arm 8 rotates toward the floor 22 or dash panel in the vehicle cabin as the driver's pedal force applied to the pedal arm 8 increases.

[0030] In the following description, the direction in which the pedal arm 8 rotates as the driver's pedal force applied to the pedal arm 8 increases is referred to as the opening direction, and the direction in which the pedal arm 8 rotates as the driver's pedal force applied to the pedal arm 8 decreases or is released is referred to as the closing direction. The opening direction is sometimes referred to as the pedal depression direction, and the closing direction is sometimes referred to as the pedal return direction.

[0031] Rotation of the pedal arm 8 in the opening direction is restricted by a full-open stopper 15. The full-open stopper 15 is a member that stops the pedal arm 8 at a fully open position where rotation of the pedal arm 8 in the opening direction is restricted when the driver applies a pedal force to the pedal arm 8. The dashed line 8a in FIG. 1 indicates a state in which the pedal arm 8 and the full-open stopper 15 abut against each other and the pedal arm 8 is in the fully open position. The full-open stopper 15 is preferably made of an elastic material such as rubber, resin, or silicone.

[0032] On the other hand, rotation of the pedal arm 8 in the closing direction is restricted by a full-close stopper 9. The full-close stopper 9 is a member that stops the pedal arm 8 at a full-close position where rotation of the pedal arm 8 in the closing direction is restricted when no pedal force is applied by the driver to the pedal arm 8. The solid line 8b in Fig. 1 indicates a state in which the pedal arm 8 and the full-close stopper 9 abut against each other and the pedal arm 8 is in the full-close position. The full-close stopper 9 is also preferably made of an elastic material such as rubber, resin, or silicone.

[0033] The spring mechanism 10 is configured to include one or more springs. The spring mechanism 10 is a mechanism that generates a biasing force that acts as a reaction force against the driver's pedal force applied to the pedal arm 8. By providing the spring mechanism 10, the brake pedal device 4 can obtain a reaction force similar to that obtained when the pedal arm 8 is connected to a master cylinder, i.e., when a reaction force is obtained by hydraulic pressure, even if the mechanical connection between the pedal arm 8 and a conventional master cylinder is eliminated.

[0034] The sensor 6 detects the pedal arm 8 or the shaft 12 and outputs a sensor signal corresponding to the angle or stroke of the pedal arm 8. The sensor 6 may be of various types, such as a magnetic sensor, an inductive sensor, an optical sensor, a load sensor, a rotary encoder, or a potentiometer. The sensor 6 is not limited to being positioned in a position overlapping the axis CL of the shaft 12, but may also be positioned away from the axis CL. The sensor signal output by the sensor 6 is transmitted to the ECU 2. In this specification, the sensor signal refers to the "sensor raw value" output from the sensor 6.

[0035] The ECU 2 is composed of a microcomputer including a processor that performs control processing and arithmetic processing, a memory unit such as ROM and RAM that stores programs and data, and peripheral circuits. The memory unit is composed of a non-transitory tangible storage medium. The ECU 2 performs various control processing and arithmetic processing based on the programs stored in the memory unit, and controls the operation of each device connected to the output port. Specifically, the ECU 2 of the first embodiment includes a signal processing device 3 as part of its electronic circuit. The signal processing device 3 processes sensor signals transmitted from the sensor 6 and generates control signals. The control circuit 24 of the ECU 2 drives and controls the brake mechanism 5 based on the control signals generated by the signal processing device 3.

[0036] Various mechanisms can be employed as the brake mechanism 5. For example, the brake mechanism 5 may be an electric brake in which an electric motor is driven by a command from the ECU 2 to press brake pads against disc brake rotors, thereby braking each wheel. Alternatively, the brake mechanism 5 may be configured to increase the hydraulic pressure of brake fluid by operating a master cylinder or a hydraulic pump, thereby driving wheel cylinders arranged on each wheel and operating the brake pads. The brake mechanism 5 may also perform normal control, ABS control, VSC control, and the like, in response to a command from the ECU 2. ABS stands for Anti-lock Braking System, and VSC stands for Vehicle Stability Control.

[0037] Next, the configuration of the signal processing device 3 that processes the sensor signal output from the sensor 6 of the brake pedal device 4 will be described with reference to FIG.

[0038] As shown in FIG. 2, the signal processing device 3 includes a behavior determining unit 16, a filter circuit 17, and a filter constant setting unit 18 as functional blocks configured with electronic circuits.

[0039] The sensor signal output from the sensor 6 is input to the behavior determination unit 16 and the filter circuit 17 .

[0040] The behavior determination unit 16 is a circuit that determines, based on a sensor signal, whether or not a bouncing behavior will occur after the pedal arm 8 rotates in the closing direction and reaches the fully closed position. The behavior determination unit 16 is configured to be able to determine whether or not a bouncing behavior will occur before the bouncing behavior occurs. Note that specific methods by which the behavior determination unit 16 determines whether or not a bouncing behavior will occur will be described in detail in the third to seventh embodiments described later.

[0041] The filter circuit 17 is a circuit that performs smoothing processing on the sensor signal according to a filter constant and generates a control signal for braking the vehicle. The larger the filter constant, the greater the smoothing degree of the change in the sensor signal that the filter circuit 17 generates. Note that various techniques can be used for the filter circuit 17, such as a moving average filter or a low-pass filter. For example, if a moving average filter is used as the filter circuit 17, the filter constant is a moving average time. For example, if a low-pass filter is used as the filter circuit 17, the filter constant is a time constant.

[0042] The filter constant setting unit 18 is a circuit that sets a filter constant used in the filter circuit 17 based on the determination result by the behavior determination unit 16. The filter constant setting unit 18 sets the filter constant when the behavior determination unit 16 determines that bouncing behavior will occur to a value larger than the filter constant when the behavior determination unit 16 determines that bouncing behavior will not occur. Specifically, when the behavior determination unit 16 determines that bouncing behavior will occur, the filter constant setting unit 18 sets the filter constant to a "filter constant for bouncing suppression." On the other hand, when the behavior determination unit 16 determines that bouncing behavior will not occur, the filter constant setting unit 18 sets the filter constant to a "filter constant for normal control." The "filter constant for bouncing suppression" is a value larger than the "filter constant for normal control," and causes the filter circuit 17 to generate a control signal that has a greater degree of smoothing of changes in the sensor signal.

[0043] Next, the control processing executed by the signal processing device 3 will be described with reference to the flowchart in Fig. 3. In the following description and drawings, steps will simply be represented as "S".

[0044] 3, the behavior determination unit 16 determines whether or not there is a risk of the rebound behavior occurring based on the sensor signal input from the sensor 6. That is, the behavior determination unit 16 determines whether or not the rebound behavior will occur after the pedal arm 8 rotates in the closing direction and reaches the fully closed position, before the rebound behavior occurs.

[0045] If the behavior determination unit 16 determines in S10 that there is a risk of bouncing behavior occurring, the process proceeds to S20. In S20, the filter constant setting unit 18 sets the filter constant to a "filter constant for bouncing suppression." This causes the filter circuit 17 to generate a control signal that smooths the change in the sensor signal to a greater degree. The control circuit 24 of the ECU 2 drives and controls the brake mechanism 5 based on the control signal. Therefore, even if the driver releases his / her foot from the pedal arm 8 while it is depressed and bouncing behavior occurs after the pedal arm 8 reaches the fully closed position, the control circuit 24 of the ECU 2 can immediately cancel the vehicle braking command to the brake mechanism 5.

[0046] On the other hand, if the behavior determination unit 16 determines in S10 that there is no risk of rebound behavior occurring, the process proceeds to S30. In S30, the filter constant setting unit 18 sets the filter constant to a "filter constant for normal control." This causes the filter circuit 17 to generate a control signal that smooths the change in the sensor signal to a relatively small degree. The control circuit 24 of the ECU 2 drives and controls the brake mechanism 5 based on the control signal. Therefore, when the driver performs a depressing operation and a releasing operation with his / her foot on the pedal arm 8, the control circuit 24 of the ECU 2 can perform vehicle braking with high response.

[0047] Next, the relationship between the sensor signal and the control signal in the control processing executed by the signal processing device 3 will be described with reference to the graph of FIG.

[0048] The horizontal axis in Figure 4 represents time, and the vertical axis represents the angle of the pedal arm 8, i.e., the pedal angle. On the vertical axis, "fully closed" refers to the angle when the pedal arm 8 is in the fully closed position, which indicates a state in which the driver is not applying the brakes. On the other hand, "fully open" on the vertical axis refers to the angle when the pedal arm 8 is in the fully open position, which indicates a state in which the driver is fully applying the brakes. In Figure 4, the dashed dotted line S represents the sensor signal, and the solid line C represents the control signal.

[0049] The sensor signal indicated by the dashed-dotted line S in Figure 4 is a raw sensor value and indicates the actual angle of the pedal arm 8. Therefore, as indicated by the dashed-dotted line S, at time t1, the driver begins to depress the pedal arm 8, and the pedal arm 8 begins to rotate in the open direction from the fully closed position. At time t2, the pedal arm 8 reaches the fully open position. At time t3, the driver releases his foot from the pedal arm 8, and the pedal arm 8 begins to rotate in the close direction from the fully open position only by the biasing force of the spring mechanism 10. At time t4, the pedal arm 8 reaches the fully closed position and collides with the fully closed stopper 9. From time t4 to t5, the fully closed stopper 9 contracts due to the collision force of the pedal arm 8, and then from time t5 to t6, the fully closed stopper 9 returns to its original shape due to its own elastic force. Therefore, from time t6 to t9, the pedal arm 8 exhibits a bouncing behavior.

[0050] The solid line C in FIG. 4 indicates the control signal generated by the filter circuit 17. From time t0 to t4, the behavior determination unit 16 determines that there is no risk of bouncing behavior occurring, and the filter constant setting unit 18 sets the filter constant to the "filter constant for normal control." As a result, the filter circuit 17 generates a control signal in which the degree of smoothing of the change in the sensor signal is relatively small. Therefore, from time t1 to t2, when the driver depresses the pedal arm 8, the delay time Δα between the sensor signal and the control signal is short. Therefore, when the pedal arm 8 is depressed, the control circuit 24 of the ECU 2 can brake the vehicle with high response.

[0051] If the behavior determination unit 16 determines that there is a risk of bouncing behavior occurring between times t3 and t4, the filter constant setting unit 18 sets the filter constant to a "filter constant for bouncing suppression" for a certain period of time from time t4 (for example, between times t4 and t9). As a result, the filter circuit 17 generates a control signal that smooths the change in the sensor signal to a greater extent. Therefore, even if bouncing behavior of the pedal arm 8 occurs between times t4 and t9, the control circuit 24 of the ECU 2 can immediately cancel the vehicle braking command to the brake mechanism 5 based on the control signal.

[0052] At time t9, a certain time after time t4, the filter constant setting unit 18 sets the filter constant to the "filter constant for normal control." As a result, when the driver starts to depress the pedal arm 8 again after time t9, the control circuit 24 of the ECU 2 can brake the vehicle with high response.

[0053] For comparison with the control processing of the first embodiment described above, the relationship between the sensor signal and the control signal in a signal processing device of a comparative example will be described with reference to the graph of FIG.

[0054] Although not shown in the drawings, the signal processing device of the comparative example only includes a filter circuit, and does not include the behavior determination unit 16 and the filter constant setting unit 18. The filter constant of the filter circuit of the comparative example is always set to a value similar to the "filter constant for bouncing suppression" described in the first embodiment.

[0055] The sensor signal indicated by the dashed dotted line S in FIG. 5, that is, the actual angle of the pedal arm 8, is the same as that described in the first embodiment.

[0056] The control signal indicated by the solid line C in Fig. 5 is generated by the filter circuit of the comparative example described above. Between times t1 and t2 when the driver depresses the pedal arm 8, the delay time Δβ between the sensor signal and the control signal is longer than the delay time Δα described in the first embodiment. Therefore, in the comparative example, when the pedal arm 8 is depressed, a delay in the vehicle braking response causes a problem of deterioration in drivability.

[0057] In contrast to the above-described comparative example, the signal processing device 3 of the first embodiment has the following advantageous effects due to its configuration. The signal processing device 3 of the first embodiment includes a behavior determination unit 16, a filter circuit 17, and a filter constant setting unit 18. The behavior determination unit 16 determines whether or not bouncing behavior will occur in the pedal arm 8 based on the sensor signal. The filter circuit 17 performs a smoothing process on the sensor signal according to the filter constant to generate a control signal. The filter constant setting unit 18 sets the filter constant when the behavior determination unit 16 determines that bouncing behavior will occur to be larger than the filter constant when the behavior determination unit 16 determines that bouncing behavior will not occur.

[0058] According to this, when the behavior determination unit 16 determines that a bouncing behavior will occur, the filter constant setting unit 18 sets a large filter constant, and the filter circuit 17 generates a control signal that greatly smooths the change in the sensor signal. Therefore, even if the driver releases his / her foot from the state in which he / she has depressed the pedal arm 8 and the pedal arm 8 exhibits a bouncing behavior, the control circuit 24 of the ECU 2 immediately cancels the vehicle braking command to the brake mechanism 5 based on the control signal in which the change in the sensor signal has been greatly smoothed. Therefore, drivability can be improved.

[0059] On the other hand, when the driver performs a depressing operation or a releasing operation with his foot on the pedal arm 8, the pedal arm 8 does not rotate in the closing direction by the biasing force of the spring mechanism 10 alone and does not collide with the full-close stopper 9, and the behavior determination unit 16 determines that a bouncing behavior will not occur. Therefore, the filter constant setting unit 18 sets a filter constant smaller than that when a bouncing behavior occurs, and the filter circuit 17 generates a control signal with a small degree of smoothing of the change in the sensor signal. Therefore, when the driver performs a depressing operation or a releasing operation with his foot on the pedal arm 8, the control circuit 24 of the ECU 2 performs vehicle braking with high responsiveness based on the control signal with a small degree of smoothing of the change in the sensor signal, thereby improving drivability.

[0060] Furthermore, according to the signal processing of the signal processing device 3, even if the pedal arm 8 exhibits a bouncing behavior, the control circuit 24 of the ECU 2 immediately cancels the vehicle braking command to the brake mechanism 5. Therefore, there is no unnecessary increase in the number of vehicle braking operations, and unnecessary wear of the brake pads, etc. can be prevented.

[0061] Furthermore, according to the signal processing of the signal processing device 3, even if the biasing force of the spring mechanism 10 provided in the brake pedal device 4 is increased, there is no need to increase the size of the fully closed stopper 9 that physically absorbs the impact force of the pedal arm 8, and drivability can be improved by control. Therefore, an increase in the size of the brake pedal device 4 due to an increase in the size of the fully closed stopper 9 can be prevented, and manufacturing costs can be reduced.

[0062] Furthermore, in the signal processing device 3 of the first embodiment, the behavior determination unit 16 may determine the magnitude of the bouncing behavior based on the sensor signal. In this case, the filter constant setting unit 18 may set the "bounce suppression filter constant" to a larger value as the bouncing behavior increases. Furthermore, the filter constant setting unit 18 may extend the time for applying the "bounce suppression filter constant" to the filter circuit 17 as the bouncing behavior increases. In detail, the filter constant setting unit 18 may extend the time from setting the "bounce suppression filter constant" to returning to the "normal control filter constant" as the bouncing behavior increases.

[0063] (Second embodiment) The second embodiment will be described. The second embodiment is different from the first embodiment in that the configuration of the signal processing device 3 and the control method thereof are changed, but the rest is the same as the first embodiment, so only the parts that are different from the first embodiment will be described.

[0064] As shown in FIG. 6, the signal processing device 3 of the second embodiment includes a behavior determining unit 16, a filter circuit 17, a fully closed signal generating unit 19, and a signal switching unit 20 as functional blocks configured with electronic circuits.

[0065] The sensor signal output from the sensor 6 is input to the behavior determination unit 16 and the filter circuit 17 .

[0066] The behavior determination unit 16 is a circuit that determines, based on a sensor signal, whether or not a bouncing behavior will occur after the pedal arm 8 rotates in the closing direction and reaches the fully closed position. The behavior determination unit 16 is configured to be able to determine whether or not a bouncing behavior will occur before the bouncing behavior occurs. Note that specific methods by which the behavior determination unit 16 determines whether or not a bouncing behavior will occur will be described in detail in the third to seventh embodiments described later.

[0067] The filter circuit 17 is a circuit that performs smoothing processing on the sensor signal according to a filter constant and generates a control signal for braking the vehicle. Various techniques can be used for the filter circuit 17, such as a moving average processing filter or a low-pass filter. In the second embodiment, the filter circuit 17 is not essential, and the signal processing device 3 can also be configured without the filter circuit 17.

[0068] The fully closed signal generating unit 19 is a circuit that generates and outputs a fully closed signal. In this specification, the fully closed signal refers to a signal value that indicates that the pedal arm 8 is in the fully closed position.

[0069] The signal switching unit 20 is a circuit that switches between the control signal generated by the filter circuit 17 and the fully-closed signal generated by the fully-closed signal generating unit 19 and outputs the switched signal based on the determination result by the behavior determining unit 16. When the behavior determining unit 16 determines that the bouncing behavior will not occur, the signal switching unit 20 outputs the control signal generated by the filter circuit 17, as shown in Fig. 6. On the other hand, when the behavior determining unit 16 determines that the bouncing behavior will occur, the signal switching unit 20 switches the control signal to the fully-closed signal generated by the fully-closed signal generating unit 19 and outputs it for a predetermined time, as shown in Fig. 7.

[0070] Next, the control process executed by the signal processing device 3 of the second embodiment will be described with reference to the flowchart of FIG.

[0071] 8, the behavior determination unit 16 determines whether or not there is a risk of the rebound behavior occurring based on the sensor signal input from the sensor 6. That is, the behavior determination unit 16 determines whether or not the rebound behavior will occur after the pedal arm 8 rotates in the closing direction and reaches the fully closed position, before the rebound behavior occurs.

[0072] If the behavior determination unit 16 determines in S110 that there is a risk of rebound behavior occurring, the process proceeds to S120. In S120, the signal switching unit 20 switches the control signal to a fully closed signal generated by the fully closed signal generation unit 19 and outputs the signal for a predetermined period of time. This causes the control circuit 24 of the ECU 2 to drive and control the brake mechanism 5 based on the fully closed signal. Therefore, even if the driver releases his / her foot from the pedal arm 8 while it is depressed and the pedal arm 8 reaches the fully closed position, and rebound behavior occurs, the control circuit 24 of the ECU 2 can immediately cancel the vehicle braking command to the brake mechanism 5.

[0073] On the other hand, if the behavior determination unit 16 determines in S110 that there is no risk of the rebound behavior occurring, the process proceeds to S130. In S130, the signal switching unit 20 outputs a normal control signal generated by the filter circuit 17. If the signal processing device 3 is configured without the filter circuit 17, the signal switching unit 20 outputs a sensor signal as a control signal. The control circuit 24 of the ECU 2 drives and controls the brake mechanism 5 based on the control signal or the sensor signal. Therefore, when the driver performs a depressing operation and a releasing operation with his / her foot on the pedal arm 8, the control circuit 24 of the ECU 2 can perform vehicle braking with high response.

[0074] Next, the control process executed by the signal processing device 3 will be described with reference to the graph of FIG. 9, in terms of the relationship between the sensor signal, the control signal, and the full-close signal.

[0075] The sensor signal indicated by the dashed dotted line S in FIG. 9, that is, the actual angle of the pedal arm 8, is the same as that described in the first embodiment.

[0076] The solid line C in Fig. 9 indicates the control signal and full-close signal output from the signal switching unit 20. From time t0 to t4, the behavior determination unit 16 determines that there is no risk of bouncing behavior occurring, and the signal switching unit 20 outputs a normal control signal generated by the filter circuit 17. Therefore, from time t1 to t2, when the driver depresses the pedal arm 8, the delay time Δα between the sensor signal and the control signal is very small. Therefore, when the pedal arm 8 is depressed, the control circuit 24 of the ECU 2 can brake the vehicle with high response.

[0077] If the behavior determination unit 16 determines that there is a risk of bouncing behavior occurring between times t3 and t4, the signal switching unit 20 switches the control signal to a full-close signal generated by the full-close signal generation unit 19 and outputs it for a predetermined time from time t4 (for example, between times t4 and t9). Therefore, even if bouncing behavior of the pedal arm 8 occurs between times t4 and t9, the control circuit 24 of the ECU 2 can immediately cancel the vehicle braking command to the brake mechanism 5 based on the full-close signal.

[0078] At time t9, a certain time after time t4, the signal switching unit 20 switches to outputting the normal control signal generated by the filter circuit 17. As a result, when the driver starts to depress the pedal arm 8 again after time t9, the control circuit 24 of the ECU 2 can brake the vehicle with high response.

[0079] The signal processing device 3 of the second embodiment described above has the following configuration and provides the following advantageous effects. The signal processing device 3 of the second embodiment includes a behavior determination unit 16 and a signal switching unit 20. The behavior determination unit 16 determines whether or not a bouncing behavior occurs in the pedal arm 8 based on the sensor signal. When the behavior determination unit 16 determines that a bouncing behavior will occur, the signal switching unit 20 switches the control signal to a fully closed signal for a predetermined time and outputs the signal.

[0080] According to this, when the behavior determination unit 16 determines that a rebound behavior will occur, the signal switching unit 20 switches the control signal to a full-close signal for a predetermined time and outputs it. Therefore, even if the driver releases his / her foot from the pedal arm 8 while depressing it and the pedal arm 8 exhibits a rebound behavior, the control circuit 24 of the ECU 2 immediately cancels the vehicle braking command to the brake mechanism 5 based on the full-close signal, thereby improving drivability.

[0081] On the other hand, when the driver performs a depressing operation or a releasing operation with his / her foot on the pedal arm 8, the pedal arm 8 does not rotate in the closing direction due to the biasing force of the spring mechanism 10 alone and does not collide with the full-close stopper 9, and the behavior determination unit 16 determines that a bouncing behavior will not occur. Therefore, the signal switching unit 20 does not switch the control signal to a full-close signal. Therefore, when the driver performs a depressing operation or a releasing operation with his / her foot on the pedal arm 8, the control circuit 24 of the ECU 2 performs vehicle braking with high responsiveness based on the control signal or the sensor signal that has been normally processed, thereby improving drivability.

[0082] Furthermore, according to the signal processing of the signal processing device 3, as in the first embodiment, there is no unnecessary increase in the number of vehicle braking operations, and unnecessary wear of the brake pads and the like can be prevented.

[0083] Furthermore, according to the signal processing of this signal processing device 3, as in the first embodiment, there is no need to increase the size of the full-close stopper 9, so that the brake pedal device 4 can be prevented from increasing in size and manufacturing costs can be reduced.

[0084] Furthermore, in the signal processing device 3 of the second embodiment, the behavior determination unit 16 may determine the magnitude of the bouncing behavior based on the sensor signal. In this case, the signal switching unit 20 may increase the time for outputting the full-close signal as the bouncing behavior increases. In detail, the signal switching unit 20 may increase the time from when it switches the normal control signal generated by the filter circuit 17 to the full-close signal generated by the full-close signal generating unit 19 until it switches back to the normal control signal generated by the filter circuit 17 as the bouncing behavior increases.

[0085] (Third to Seventh Embodiments) The third to seventh embodiments, in contrast to the first and second embodiments, describe specific methods by which the behavior determination unit 16 determines whether or not a bouncing behavior occurs. In the descriptions of the third to seventh embodiments, the signal processing device 3 is described as including the behavior determination unit 16, the filter circuit 17, and the filter constant setting unit 18, similar to the first embodiment. However, without being limited thereto, in the descriptions of the third to seventh embodiments, the signal processing device 3 may also include the behavior determination unit 16, the filter circuit 17, the full-close signal generating unit 19, and the signal switching unit 20, similar to the second embodiment.

[0086] (Third embodiment) The relationship between the sensor signal and the control signal at the pedal angle shown in the upper part of the graph in Fig. 10 is substantially the same as that in the graph in Fig. 4 referred to in the description of the first embodiment, and therefore will not be described again. Note that the signal processing device 3 of the third embodiment can output a control signal that indicates a fully closed state when the sensor signal is smaller than a value indicating a fully closed state. Specifically, in the upper part of the graph in Fig. 10, the signal processing device 3 can output a control signal that indicates a fully closed state between times t4 and t6 and between times t8 and t9. This is the same in the first and second embodiments described above, and in the fourth to seventh embodiments described below.

[0087] The line V in the lower part of the graph in Fig. 10 indicates the operating speed of the pedal arm 8. The behavior determination unit 16 included in the signal processing device 3 of the third embodiment is capable of calculating the operating speed of the pedal arm 8 from the differential value of the sensor signal. Then, the behavior determination unit 16 determines that a bouncing behavior will occur when the pedal arm 8 rotates in the closing direction at a speed equal to or greater than a predetermined speed threshold Th_v, or when the pedal arm 8 reaches the fully closed position at a speed equal to or greater than the predetermined speed threshold Th_v.

[0088] The predetermined speed threshold Th_v is set by experiment or the like depending on the pedal force characteristics of the spring mechanism 10 provided in the brake pedal device 4, and is stored in advance in the memory of the signal processing device 3. The memory is a non-transient tangible storage medium. A speed equal to or greater than the predetermined speed threshold Th_v means a speed whose absolute value is equal to or greater than the predetermined speed threshold Th_v, regardless of the direction in which the pedal arm 8 moves.

[0089] In the third embodiment described above, the behavior determination unit 16 determines that a bouncing behavior will occur when the pedal arm 8 rotates in the closing direction at a speed equal to or greater than a predetermined speed threshold Th_v, or when the pedal arm 8 reaches the fully closed position at a speed equal to or greater than a predetermined speed threshold Th_v. According to this, when the driver releases his / her foot from the state in which he / she has depressed the pedal arm 8, the pedal arm 8 rotates in the closing direction at a speed equal to or greater than a predetermined speed threshold Th_v due only to the biasing force of the spring mechanism 10, and when it collides with the full-close stopper 9 in the full-close position, a bouncing behavior occurs. Therefore, the behavior determination unit 16 can determine whether or not a bouncing behavior will occur before the bouncing behavior occurs by calculating the operating speed when the pedal arm 8 rotates in the closing direction from the differential value of the sensor signal.

[0090] Furthermore, in the signal processing device 3 of the third embodiment, the behavior determination unit 16 may determine the magnitude of the bouncing behavior based on a sensor signal. Specifically, the behavior determination unit 16 determines that the greater the speed at which the pedal arm 8 rotates in the closing direction, the greater the bouncing behavior. In this case, the filter constant setting unit 18 described in the first embodiment may set a larger "filter constant for bouncing suppression" as the bouncing behavior increases. Furthermore, the filter constant setting unit 18 may extend the time for which the "filter constant for bouncing suppression" is applied to the filter circuit 17 as the bouncing behavior increases. Furthermore, in this case, the signal switching unit 20 described in the second embodiment may extend the time for which the fully closed signal is output as the bouncing behavior increases.

[0091] (Fourth embodiment) The relationship between the sensor signal and the control signal at the pedal angle shown in the upper part of the graph in FIG. 11 is substantially the same as that in the graph in FIG. 4 referred to in the description of the first embodiment, and therefore will not be described again. Line I in the lower part of the graph in FIG. 11 indicates the count value of the time the pedal arm 8 remains in the fully closed position and in a position further in the closing direction than the fully closed position. The behavior determination unit 16 included in the signal processing device 3 of the fourth embodiment has a counter circuit that counts the time the pedal arm 8 remains in the fully closed position and in a position further in the closing direction than the fully closed position, and is capable of counting this time. Specifically, the vertical axis in the lower part of the graph in FIG. 11 indicates the count value obtained by counting the time the pedal arm 8 remains in the fully closed position and in a position further in the closing direction than the fully closed position. When the pedal arm 8 moves in the opening direction from the fully closed position, the count value is reset. In line I of the graph in FIG. 11, the count value is reset at time t1, starts counting at time t4, and is reset at time t6.

[0092] The behavior determination unit 16 determines that a bouncing behavior occurs when the time that the pedal arm 8 stays in the fully closed position or in a position further in the closing direction than the fully closed position, i.e., the counter value, is smaller than a predetermined time threshold Th_t. The time threshold Th_t is set to a time shorter than the time (e.g., 0.25 seconds) required for a person to vibrate the pedal arm 8 multiple times at the fastest speed with their foot, and is stored in advance in the memory of the signal processing device 3.

[0093] In the fourth embodiment described above, the behavior determination unit 16 determines that a bouncing behavior will occur if the time that the pedal arm 8 stays in the fully closed position or in a position further closing than the fully closed position is shorter than a predetermined time threshold Th_t. According to this, when the pedal arm 8 rotates in the closing direction due only to the biasing force of the spring mechanism 10 and collides with the full-close stopper 9, the pedal arm 8 abuts against the full-close stopper 9 for only a short time that a person cannot operate it with their foot at the fastest speed, and then exhibits a bouncing behavior. Therefore, the behavior determination unit 16 can determine whether or not a bouncing behavior will occur before the bouncing behavior occurs by detecting the time that the pedal arm 8 stays in the full-close position and in a position further in the closing direction than the full-close position.

[0094] Furthermore, in the signal processing device 3 of the fourth embodiment, the behavior determination unit 16 may determine the magnitude of the bouncing behavior based on a sensor signal. Specifically, the behavior determination unit 16 determines that the bouncing behavior is greater the shorter the time that the pedal arm 8 stays in the fully closed position and in a position further in the closing direction than the fully closed position. In this case, the filter constant setting unit 18 described in the first embodiment may set a larger "filter constant for bouncing suppression" the greater the bouncing behavior. Furthermore, the filter constant setting unit 18 may extend the time for which the "filter constant for bouncing suppression" is applied to the filter circuit 17 the greater the bouncing behavior. Furthermore, in this case, the signal switching unit 20 described in the second embodiment may extend the time for which the fully closed signal is output the greater the bouncing behavior.

[0095] (Fifth embodiment) The relationship between the sensor signal and the control signal at the pedal angle shown in the upper part of the graph in Fig. 12 is substantially the same as that shown in the graph in Fig. 4 referred to in the description of the first embodiment, and therefore a description thereof will be omitted. The line V in the middle part of the graph in Fig. 12 represents the operating speed of the pedal arm 8, and is substantially the same as that shown in the line V in the lower part of the graph in Fig. 10 referred to in the description of the third embodiment, and therefore a description thereof will be omitted.

[0096] The line G in the lower part of the graph in FIG. 12 indicates the acceleration of the movement of the pedal arm 8. The behavior determination unit 16 included in the signal processing device 3 of the fifth embodiment is capable of calculating the acceleration of the movement of the pedal arm 8 from the second-order differential value of the sensor signal. The behavior determination unit 16 determines that the bouncing behavior occurs when the pedal arm 8 rotates in the closing direction at an acceleration equal to or greater than a predetermined acceleration threshold Th_a, or when the pedal arm 8 reaches the fully closed position at an acceleration equal to or greater than the predetermined acceleration threshold Th_a. Note that an acceleration equal to or greater than the predetermined acceleration threshold Th_a refers to an acceleration whose absolute value is equal to or greater than the predetermined acceleration threshold Th_a, regardless of the direction in which the pedal arm 8 moves. The predetermined acceleration threshold Th_a is either a constant value or a value uniquely determined depending on the angle or stroke of the pedal arm 8 based on the characteristics of the spring mechanism 10 and the mass of the pedal arm 8.

[0097] FIG. 13 is a graph showing the relationship between the angle θ or stroke amount of the pedal arm 8 and the biasing force F(θ) acting on the pedal arm 8 from the spring mechanism 10. This graph is set when the spring mechanism 10 is designed, and is called the pedal force characteristics of the spring mechanism 10. The solid line D in the graph of FIG. 13 shows the relationship between the angle θ or stroke amount of the pedal arm 8 and the biasing force F(θ) acting on the pedal arm 8 from the spring mechanism 10 when the pedal arm 8 rotates in the opening direction. The dashed-dotted line E shows the relationship between the angle θ or stroke amount of the pedal arm 8 and the biasing force F(θ) acting on the pedal arm 8 from the spring mechanism 10 when the pedal arm 8 rotates in the closing direction.

[0098] Here, when the pedal arm 8 rotates in the closing direction, the force F(θ) acting on the pedal arm 8 from the spring mechanism 10 at a predetermined angle θ, the acceleration a at that predetermined angle θ, and the mass m of the pedal arm 8 have the following relationship as expressed in Equation 1 from the equation of motion. F(θ)=ma (Equation 1)

[0099] From the above formula 1, when the pedal arm 8 rotates in the closing direction, the acceleration a at a predetermined angle θ has the relationship of the following formula 2. a=F(θ) / m (Equation 2)

[0100] As described above, the biasing force F(θ) acting on the pedal arm 8 from the spring mechanism 10 at a predetermined angle θ has a value that is set as the pedal force characteristic of the spring mechanism 10 at the time of design.

[0101] Therefore, when the pedal arm 8 rotates in the closing direction, if the acceleration a at a predetermined angle θ is smaller than the value obtained by dividing the biasing force F(θ) set at the predetermined angle θ during design by the mass m of the pedal arm 8, it is considered that the driver's foot is placed on the pedal arm 8. In this case, no bouncing behavior occurs after the pedal arm 8 collides with the fully closed stopper 9.

[0102] On the other hand, when the pedal arm 8 rotates in the closing direction, if the acceleration a at a predetermined angle θ is equivalent to the value obtained by dividing the biasing force F(θ) set at the predetermined angle θ at the time of design by the mass m of the pedal arm 8, the following can be considered. That is, in this case, the driver's foot is not placed on the pedal arm 8, and the pedal arm 8 rotates in the closing direction only by the biasing force of the spring mechanism 10. Therefore, it is considered that a bouncing behavior occurs after the pedal arm 8 hits the full-close stopper 9. Note that the phrase "the acceleration a at a predetermined angle θ is equivalent to the value obtained by dividing the biasing force F(θ) set at the predetermined angle θ at the time of design by the mass m of the pedal arm 8" is intended to include a slight decrease in the acceleration a due to friction of the shaft 12, air resistance to the pedal arm 8, etc. Therefore, by setting the predetermined acceleration threshold Th_a to a value that is uniquely determined in accordance with the angle or stroke of the pedal arm 8 based on the characteristics of the spring mechanism 10 and the mass m of the pedal arm 8, it is possible to accurately determine whether a bouncing behavior occurs. The predetermined acceleration threshold Th_a may be determined experimentally, and is a value that is uniquely determined, including an error, as to what level of acceleration is required to cause a rebound.

[0103] In addition, if the pedal arm 8 rotates at an acceleration greater than a certain value, a bouncing behavior occurs after the pedal arm 8 collides with the fully closed stopper 9, so it is also possible to set the predetermined acceleration threshold Th_a to a certain constant value.

[0104] In the fifth embodiment described above, the behavior determination unit 16 determines that a bouncing behavior will occur if an acceleration equal to or greater than a predetermined acceleration threshold Th_a occurs while the pedal arm 8 rotates in the closing direction and reaches the fully closed position. According to this, when the driver releases his / her foot from the pedal arm 8 while it is depressed, the pedal arm 8 rotates in the closing direction at an acceleration equal to or greater than a predetermined acceleration due only to the biasing force of the spring mechanism 10, and when it collides with the full-close stopper 9 in the full-close position, a bouncing behavior occurs. Therefore, the behavior determination unit 16 can determine whether or not a bouncing behavior will occur before the bouncing behavior occurs by calculating the acceleration of the pedal arm 8 from the second-order differential value of the sensor signal.

[0105] Furthermore, in the fifth embodiment, the predetermined acceleration threshold value Th_a used by the behavior determination unit 16 to determine whether or not a bouncing behavior occurs is a constant value, or a value that is uniquely determined according to the angle or stroke amount of the pedal arm 8 based on the characteristics of the spring mechanism 10 and the mass m of the pedal arm 8. This allows the behavior determination unit 16 to accurately determine whether or not a bouncing behavior will occur.

[0106] Furthermore, in the signal processing device 3 of the fifth embodiment, the behavior determination unit 16 may determine the magnitude of the bouncing behavior based on a sensor signal. Specifically, the behavior determination unit 16 determines that the greater the acceleration when the pedal arm 8 rotates in the fully closed direction, the greater the bouncing behavior. In this case, the filter constant setting unit 18 described in the first embodiment may set a larger "filter constant for bouncing suppression" as the bouncing behavior increases. Furthermore, the filter constant setting unit 18 may extend the time for which the "filter constant for bouncing suppression" is applied to the filter circuit 17 as the bouncing behavior increases. Furthermore, in this case, the signal switching unit 20 described in the second embodiment may extend the time for which the fully closed signal is output as the bouncing behavior increases.

[0107] (Sixth embodiment) The relationship between the sensor signal and the control signal at the pedal angle shown in the graph of Fig. 14 is substantially the same as that shown in the graph of Fig. 4 referred to in the description of the first embodiment, and therefore will not be described again. Note that, for ease of explanation, the graph of Fig. 14 exaggerates the distance that the pedal arm 8 moves in the fully closing direction from the fully closed position between times t4 and t5.

[0108] The behavior determination unit 16 determines that a bouncing behavior will occur if the pedal arm 8 has moved further in the closing direction from the fully closed position by a predetermined distance threshold Th_d or more. The reason for this is that if the collision force between the pedal arm 8 and the fully closed stopper 9 is large, the fully closed stopper 9 will bend significantly, and then the bouncing behavior will occur. Therefore, the behavior determination unit 16 determines whether the pedal arm 8 has caused the fully closed stopper 9 to bend significantly due to the collision force, that is, whether the pedal arm 8 has moved further in the closing direction from the fully closed position by a distance threshold Th_d or more. This allows the behavior determination unit 16 to determine whether a bouncing behavior will occur before the bouncing behavior occurs.

[0109] Furthermore, in the signal processing device 3 of the sixth embodiment, the behavior determination unit 16 may determine the magnitude of the bouncing behavior based on a sensor signal. Specifically, the behavior determination unit 16 determines that the greater the distance that the pedal arm 8 has moved in the closing direction from the fully closed position, the greater the bouncing behavior. In this case, the filter constant setting unit 18 described in the first embodiment may set a larger "filter constant for bouncing suppression" as the bouncing behavior increases. Furthermore, the filter constant setting unit 18 may extend the time for which the "filter constant for bouncing suppression" is applied to the filter circuit 17 as the bouncing behavior increases. Furthermore, in this case, the signal switching unit 20 described in the second embodiment may extend the time for which the fully closed signal is output as the bouncing behavior increases.

[0110] (Seventh embodiment) 15 , the brake pedal device 4 to which the signal processing device 3 of the seventh embodiment is applied is provided with a load sensor 21 that detects whether or not the pedal force of the driver is applied to the pedal arm 8. A signal output from the load sensor 21 is transmitted to the signal processing device 3.

[0111] The relationship between the sensor signal and the control signal at the pedal angle shown in the upper part of the graph in FIG. 16 is substantially the same as that in the graph in FIG. 4 referred to in the description of the first embodiment, and therefore will not be described again. The line K in the lower part of the graph in FIG. 16 represents the signal output from the load sensor 21, i.e., the load sensor value. When the load sensor value is equal to or less than a predetermined load threshold Th_p, this represents a state in which the driver's pedal force is not being applied to the pedal arm 8, i.e., the driver's foot is off the pedal arm 8. In the graph in FIG. 16, the line K represents the state in which the driver's pedal force is applied to the pedal arm 8 from time t1 and is no longer applied to the pedal arm 8 from time t3 onward. That is, the driver starts depressing the pedal arm 8 from time t1, depresses the pedal arm 8 to the fully open position at time 2, and then releases his / her foot from the pedal arm 8 at time t3. Therefore, as shown by the dashed-dotted line S in the upper part of the graph in FIG. 16, the pedal arm 8 rotates in the closing direction only by the biasing force of the spring mechanism 10 from time t3 onward, hits the fully closed stopper 9 at time t4, and then exhibits a bouncing behavior.

[0112] The behavior determination unit 16 determines, based on the output signal of the load sensor 21 and the sensor signal, that the bouncing behavior will occur if the pedal arm 8 rotates in the closing direction and reaches the fully closed position while the driver's depression force is not being applied to the pedal arm 8. The reason for this is that the bouncing behavior occurs when the driver releases his / her foot from the state in which he / she has depressed the pedal arm 8, and the pedal arm 8 rotates in the closing direction only by the biasing force of the spring mechanism 10 and collides with the fully closed stopper 9 at the fully closed position. Therefore, the behavior determination unit 16 can determine whether the bouncing behavior will occur before the bouncing behavior occurs, depending on whether the driver's depression force is being applied to the pedal arm 8 when the pedal arm 8 rotates in the closing direction and reaches the fully closed position.

[0113] (Eighth embodiment) The eighth embodiment differs from the first to seventh embodiments in that the configuration of the brake pedal device 4 is changed, but the rest is the same as the first to seventh embodiments, so only the parts that differ from the first to seventh embodiments will be described.

[0114] 17, the brake pedal device 4 to which the signal processing device 3 of the eighth embodiment is applied is a pendant-type pedal device. A pendant-type pedal device is one in which all or most of the pedal tread surface 14, which is the portion of the pedal arm 8 to which the driver applies a pedal force, is located below the rotation axis CL of the pedal arm 8 in the vertical direction when mounted on the vehicle (i.e., below the vehicle).

[0115] The housing 7 serving as a support is fixed to the dash panel 23 or the like by bolts or the like (not shown). The pedal arm 8 is supported rotatably relative to the housing 7. The dashed line 8a in Fig. 17 indicates a state in which the pedal arm 8 and the full-open stopper 15 abut against each other and the pedal arm 8 is in the fully open position. The solid line 8b in Fig. 17 indicates a state in which the pedal arm 8 and the full-closed stopper 9 abut against each other and the pedal arm 8 is in the fully closed position.

[0116] The sensor 6 detects the pedal arm 8 or the shaft 12 and outputs a sensor signal corresponding to the angle or stroke of the pedal arm 8. The sensor signal output by the sensor 6 is transmitted to the ECU 2. The signal processing device 3 described in the first to seventh embodiments is incorporated in the ECU 2. Note that, in the configuration of the eighth embodiment, the signal processing device 3 is not limited to being incorporated in the ECU 2, and may also be configured as an integrated circuit such as an IC or ASIC integrated with the sensor 6 provided in the brake pedal device 4.

[0117] The eighth embodiment described above can also achieve the same effects as the first to seventh embodiments.

[0118] (Other embodiments) The present disclosure is not limited to the above-described embodiments and can be modified as appropriate. Furthermore, the above-described embodiments are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above-described embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above-described embodiments, when numerical values ​​such as the number, numerical value, amount, and range of components of the embodiments are mentioned, they are not limited to the specific number unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above-described embodiments, when the shape, positional relationship, etc. of components, etc. are mentioned, they are not limited to the shape, positional relationship, etc. unless specifically stated or limited to a specific shape, positional relationship, etc. in principle.

[0119] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0120] (Aspects of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] a support (7) attached to the vehicle; a pedal arm (8) that is rotatable about a predetermined axis (CL) relative to the support, that rotates in an opening direction when the driver's pedal force increases, and that rotates in a closing direction when the driver's pedal force decreases or is released; a spring mechanism (10) that applies a biasing force to the pedal arm as a reaction force against the pedal force of the driver; a full-close stopper (9) that stops the pedal arm at a full-close position where rotation of the pedal arm in the closing direction is restricted when no pedal force is applied by the driver to the pedal arm; a sensor (6) that outputs a sensor signal corresponding to the angle or stroke amount of the pedal arm; a behavior determination unit (16) that determines, based on the sensor signal, whether or not a rebound behavior occurs after the pedal arm rotates in the closing direction and reaches the fully closed position; A filter circuit (17) performs smoothing processing on the sensor signal in accordance with a filter constant and generates a control signal for braking the vehicle, the larger the filter constant, The above the filter circuit that generates the control signal by increasing the degree of smoothing of the change in the sensor signal; a filter constant setting unit (18) that sets the filter constant when the behavior determination unit determines that the bouncing behavior will occur to a value greater than the filter constant when the behavior determination unit determines that the bouncing behavior will not occur. [Second viewpoint] a support (7) attached to the vehicle; a pedal arm (8) that is rotatable about a predetermined axis (CL) relative to the support, that rotates in an opening direction when the driver's pedal force increases, and that rotates in a closing direction when the driver's pedal force decreases or is released; a spring mechanism (10) that applies a biasing force to the pedal arm as a reaction force against the pedal force of the driver; a full-close stopper (9) that stops the pedal arm at a full-close position where rotation of the pedal arm in the closing direction is restricted when no pedal force is applied by the driver to the pedal arm; a sensor (6) that outputs a sensor signal corresponding to the angle or stroke amount of the pedal arm; and a signal processing device for use in a brake-by-wire system (1), the signal processing device processing a sensor signal output from the sensor of a brake pedal device including the sensor (6), a behavior determination unit (16) that determines, based on the sensor signal, whether or not a rebound behavior occurs after the pedal arm rotates in the closing direction and reaches the fully closed position; and a signal switching unit (20) that, when the behavior determination unit determines that the bouncing behavior will occur, switches a control signal for braking the vehicle to a signal value indicating that the pedal arm is in the fully closed position for a predetermined time and outputs the signal. [Third Perspective] The signal processing device according to the first or second aspect, wherein the behavior determination unit calculates the operating speed of the pedal arm from the differential value of the sensor signal, and determines that the bouncing behavior will occur when the pedal arm rotates in the closing direction at a speed equal to or greater than a predetermined speed threshold (Th_v) or when the pedal arm reaches the fully closed position at a speed equal to or greater than the predetermined speed threshold. [Fourth viewpoint] The signal processing device according to any one of the first to third aspects, wherein the behavior determination unit determines that the bouncing behavior will occur if the time that the pedal arm stays in the fully closed position and in a position further closing than the fully closed position is shorter than a predetermined time threshold (Th_t). [Fifth viewpoint] The signal processing device according to any one of the first to fourth aspects, wherein the behavior determination unit calculates the acceleration of the pedal arm movement from the second-order differential value of the sensor signal, and determines that the bouncing behavior will occur if an acceleration equal to or greater than a predetermined acceleration threshold (Th_a) occurs while the pedal arm rotates in the closing direction and reaches the fully closed position. [Sixth viewpoint] The signal processing device according to a fifth aspect, wherein the predetermined acceleration threshold is a constant value or a value that is uniquely determined depending on the angle or stroke of the pedal arm based on the characteristics of the spring mechanism and the mass of the pedal arm. [Seventh viewpoint] The signal processing device according to any one of the first to sixth aspects, wherein the behavior determination unit determines that the bouncing behavior will occur when the pedal arm moves further in the closing direction from the fully closed position by more than a predetermined distance threshold (Th_d). [Eighth viewpoint] The brake pedal device further includes a load sensor (21) that detects whether or not the driver's pedal force is applied to the pedal arm. The signal processing device according to any one of the first to seventh aspects, wherein the behavior determination unit determines, based on the output signal of the load sensor and the sensor signal, that the bouncing behavior will occur if the pedal arm rotates in the closing direction and reaches the fully closed position while the driver's pedal force is not being applied to the pedal arm. [Ninth viewpoint] the behavior determination unit is capable of determining the magnitude of the bouncing behavior based on the sensor signal, The signal processing device according to a first aspect, wherein the filter constant setting unit sets the filter constant to a larger value as the bouncing behavior increases. [10th viewpoint] the behavior determination unit is capable of determining the magnitude of the bouncing behavior based on the sensor signal, The signal processing device according to the first or ninth aspect, wherein the filter constant setting unit increases the time from when the behavior determination unit determines that the bouncing behavior will occur to when the filter constant setting unit returns to the filter constant when the behavior determination unit determines that the bouncing behavior will not occur, as the bouncing behavior becomes larger. [11th viewpoint] the behavior determination unit is capable of determining the magnitude of the bouncing behavior based on the sensor signal, The signal processing device according to a second aspect, wherein the signal switching unit increases the predetermined time from when the control signal for braking the vehicle is switched to the signal value indicating that the pedal arm is in the fully closed position until when the control signal is returned to the value when the behavior determination unit determines that the bouncing behavior will not occur, as the bouncing behavior increases.

Claims

1. a support (7) attached to the vehicle; a pedal arm (8) that is rotatable about a predetermined axis (CL) relative to the support, that rotates in an opening direction when the driver's pedal force increases, and that rotates in a closing direction when the driver's pedal force decreases or is released; a spring mechanism (10) that applies a biasing force to the pedal arm as a reaction force against the pedal force of the driver; a full-close stopper (9) that stops the pedal arm at a full-close position where rotation of the pedal arm in the closing direction is restricted when no pedal force is applied by the driver to the pedal arm; a sensor (6) that outputs a sensor signal corresponding to the angle or stroke amount of the pedal arm; and a signal processing device for use in a brake-by-wire system (1), the signal processing device processing a sensor signal output from the sensor of a brake pedal device (4), the signal processing device comprising: a behavior determination unit (16) that determines, based on the sensor signal, whether or not a rebound behavior occurs after the pedal arm rotates in the closing direction and reaches the fully closed position; a filter circuit (17) that performs smoothing processing on the sensor signal in accordance with a filter constant and generates a control signal for braking the vehicle, the filter circuit generating the control signal with a greater degree of smoothing of the change in the sensor signal as the filter constant increases; a filter constant setting unit (18) that sets the filter constant when the behavior determination unit determines that the bouncing behavior will occur to a value greater than the filter constant when the behavior determination unit determines that the bouncing behavior will not occur.

2. a support (7) attached to the vehicle; a pedal arm (8) that is rotatable about a predetermined axis (CL) relative to the support, that rotates in an opening direction when the driver's pedal force increases, and that rotates in a closing direction when the driver's pedal force decreases or is released; a spring mechanism (10) that applies a biasing force to the pedal arm as a reaction force against the pedal force of the driver; a full-close stopper (9) that stops the pedal arm at a full-close position where rotation of the pedal arm in the closing direction is restricted when no pedal force is applied by the driver to the pedal arm; a sensor (6) that outputs a sensor signal according to the angle or stroke amount of the pedal arm; and a signal processing device for use in a brake-by-wire system (1), the signal processing device processing a sensor signal output from the sensor of a brake pedal device including the sensor (6), a behavior determination unit (16) that determines, based on the sensor signal, whether or not a rebound behavior occurs after the pedal arm rotates in the closing direction and reaches the fully closed position; and a signal switching unit (20) that, when the behavior determination unit determines that the bouncing behavior will occur, switches a control signal for braking the vehicle to a signal value indicating that the pedal arm is in the fully closed position for a predetermined time and outputs the signal.

3. 3. The signal processing device according to claim 1, wherein the behavior determination unit calculates the operating speed of the pedal arm from the differential value of the sensor signal, and determines that the bouncing behavior will occur when the pedal arm rotates in the closing direction at a speed equal to or greater than a predetermined speed threshold (Th_v) or when the pedal arm reaches the fully closed position at a speed equal to or greater than the predetermined speed threshold.

4. 3. The signal processing device according to claim 1, wherein the behavior determination unit determines that the bouncing behavior occurs when the time that the pedal arm stays at the fully closed position and at a position further in the closing direction than the fully closed position is shorter than a predetermined time threshold (Th_t).

5. 3. The signal processing device according to claim 1, wherein the behavior determination unit calculates the acceleration of the pedal arm movement from the second-order differential value of the sensor signal, and determines that the bouncing behavior will occur if an acceleration equal to or greater than a predetermined acceleration threshold (Th_a) occurs while the pedal arm rotates in the closing direction and reaches the fully closed position.

6. 6. The signal processing device according to claim 5, wherein the predetermined acceleration threshold is a constant value or a value that is uniquely determined depending on the angle or stroke of the pedal arm based on the characteristics of the spring mechanism and the mass of the pedal arm.

7. The signal processing device according to claim 1 , wherein the behavior determination unit determines that the bouncing behavior occurs when the pedal arm moves further in the closing direction from the fully closed position by a distance equal to or greater than a predetermined distance threshold (Th_d).

8. The brake pedal device further includes a load sensor (21) that detects whether or not the driver's pedal force is applied to the pedal arm.

3. The signal processing device according to claim 1, wherein the behavior determination unit determines that the bouncing behavior will occur when the pedal arm rotates in the closing direction and reaches the fully closed position while the driver's pedal force is not being applied to the pedal arm, based on the output signal of the load sensor and the sensor signal.

9. the behavior determination unit is capable of determining the magnitude of the bouncing behavior based on the sensor signal, The signal processing device according to claim 1 , wherein the filter constant setting unit sets the filter constant to a larger value as the bouncing behavior increases.

10. the behavior determination unit is capable of determining the magnitude of the bouncing behavior based on the sensor signal, 10. The signal processing device according to claim 1, wherein the filter constant setting unit increases a time period from when the behavior determination unit determines that the bouncing behavior will occur to when the filter constant setting unit returns to the filter constant when the behavior determination unit determines that the bouncing behavior will not occur, as the bouncing behavior becomes larger.

11. the behavior determination unit is capable of determining the magnitude of the bouncing behavior based on the sensor signal, 3. The signal processing device according to claim 2, wherein the signal switching unit increases the predetermined time from when the control signal for braking the vehicle is switched to the signal value indicating that the pedal arm is in the fully closed position until when the behavior determination unit returns the control signal to the value when the bouncing behavior is determined not to occur, as the bouncing behavior increases.

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