JP2012040964A - Vehicle brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle brake control device for properly producing a reaction change of a brake pedal when using mechanical and electric type brake devices for braking a vehicle.SOLUTION: During controlling braking torque by in-wheel motors 15-18 and brake mechanisms 21-24, an electronic control unit 26 inputs a pedal operation amount detected by a brake sensor 28 to determine required braking torque for braking the vehicle Ve. The unit 26 periodically changes the braking torque by the motors 15-18 when the required braking torque is greater than a predetermined value. On the other hand, the unit 26 periodically changes the braking torque generated by the mechanisms 21-22 into an opposite phase to the periodically changed braking torque by the motors 15-18. Thus, the unit 26 periodically changes the reaction of the pedal mechanically connected to the mechanisms 21-24.

Description

  The present invention relates to a vehicle braking control device applied to a vehicle having an electric force generating means for generating a driving force or a braking force at least on wheels.

  In recent years, as one form of an electric vehicle as a vehicle having an electric force generating means for generating a driving force or a braking force at least on a wheel, an electric motor (motor) is disposed in or near the wheel of the wheel, and the wheel is driven by this electric motor. A so-called in-wheel motor type vehicle that is directly driven has been developed. In this in-wheel motor type vehicle, the motor provided for each wheel (drive wheel) is individually controlled to rotate, that is, each motor is individually controlled by power running control or regenerative control to be applied to each drive wheel. The driving torque or the braking torque can be individually controlled, and the driving force and braking force of the vehicle can be appropriately controlled according to the running state.

  In particular, by utilizing the fact that the drive torque or braking torque applied to each drive wheel can be individually controlled, in particular, an in-wheel motor operated as an electric brake device and a mechanical brake device operated by hydraulic pressure Has been proposed to control the braking torque generated in each wheel. For example, the following Patent Document 1 includes a composite brake device including mechanical and electric brakes, and controls the stator frequency of the motor based on the rotation frequency detected by the rotation frequency sensor provided on each wheel. A vehicle for activating an anti-lock brake is shown.

  Further, in Patent Document 2 below, when ABS control is executed, the hydraulic braking force command value is held at the same value as the previous hydraulic control command value, and the regenerative braking force command value is set to the braking force correction value. 1 shows a braking control device for an electric vehicle which corrects the total braking force to a small value.

JP-A-6-335105 JP-A-5-270387

  By the way, in the conventional vehicle and the braking control device, for example, as shown in FIGS. 5 (a) and 5 (b), a required braking torque for braking the vehicle according to a brake operation by the driver is determined. This required braking torque is generated as a total braking torque which is the sum of the braking torque by the mechanical brake device and the braking torque by the electric brake device (that is, the in-wheel motor). For example, when releasing the tire lock state by ABS control, the braking torque by the mechanical brake device and the braking torque by the electric brake device are properly used according to the situation.

  In this case, in the case of releasing the locked state of the tire using the mechanical brake device (that is, ABS control), as shown in FIG. 5C, the hydraulic pressure (hydraulic pressure) for operating the mechanical brake device is used. ), The reaction force at the brake pedal varies, so that the driver can recognize the road surface condition by perceiving the reaction force varying through the brake pedal. On the other hand, when releasing the tire locked state using an electric brake device, the driver may not be able to accurately grasp the road surface state because the reaction force does not fluctuate in the brake pedal. There is. Furthermore, when the state of releasing the tire locked state by the electric brake device is shifted to the state of releasing the tire locked state by the mechanical brake device, the reaction force of the brake pedal is suddenly changed periodically. Since the vehicle will fluctuate, the driver may not only be able to grasp the road surface condition, but may also feel uncomfortable with a sudden reaction force change of the brake pedal.

  The present invention has been made to cope with the above-described problems, and an object of the present invention is to provide a reaction force in a brake pedal when a vehicle is braked by cooperation of a mechanical brake device and an electric brake device. An object of the present invention is to provide a vehicle braking control device that appropriately causes a change.

  In order to achieve the above object, the feature of the present invention is applied to a vehicle having electric power generation means for generating a driving force or a braking force at least on wheels, and is operated by a driver to brake the vehicle. Brake operation amount detection means for detecting the operation amount of the operation means, braking force generation means for generating a braking force for the wheels rotated by the electric force generation means, and the braking operation amount detection means. In the vehicle braking control device comprising: the electric force generating means; and the braking control means for controlling the braking force generated by the braking force generating means corresponding to the operation amount of the braking operation means. The operation of the braking operation means detected by the braking operation amount detection means when the electric force generation means and the braking force generation means are generating a braking force. There the reaction force against the driver's operation to the brake operation means in accordance with the size of the size that includes a reaction force variation means for periodically change.

  According to this, when the electric force generating means (electric brake device) and the braking force generating means (mechanical brake device) generate braking force to brake the vehicle, the driver operates the braking operation means. Depending on the magnitude of the amount, that is, the magnitude of the deceleration generated in the vehicle, the reaction force variation means can periodically vary the magnitude of the reaction force. Therefore, the driver can perceive periodic fluctuations in the magnitude of the reaction force via the braking operation means when operating the braking operation means to be larger than a certain operation amount to brake the vehicle. As a result, the reaction force variation means may, for example, feel uncomfortable with the reaction force variation due to the start of the ABS control by periodically varying the magnitude of the reaction force before the ABS control is started. Absent.

  Further, since the magnitude of the reaction force in the braking operation means can be periodically changed before the ABS control is started, for example, the driver can predict whether or not the ABS control is started. . Therefore, the driver can appropriately grasp the road surface state and can calmly brake the vehicle even when the ABS control is started.

  In this case, the braking force generation means is mechanically connected to the braking operation means and generates a braking force to be applied to the wheels due to an operation on the braking operation means by a driver. Preferably, the reaction force variation means may periodically vary the magnitude of the reaction force by periodically varying the braking force applied to the wheels by the braking force generation means. In this case, for example, the braking force generating means may generate a braking force according to the magnitude of the hydraulic pressure generated in accordance with the operation of the braking operation means by the driver.

  According to these, when the electric force generating means and the braking force generating means each generate braking force to brake the vehicle, more specifically, by periodically varying the braking force by the braking force generating means, By periodically varying the magnitude of the hydraulic pressure supplied to the braking force generating means, the magnitude of the reaction force in the braking operation means mechanically coupled to the braking force generating means can be periodically varied. it can. Therefore, the magnitude of the reaction force in the braking operation means can be periodically changed more reliably. Further, even in a situation where the electric force generating means mainly generates a braking force, the magnitude of the reaction force in the braking operation means can be periodically changed by periodically changing the braking force of the braking force generating means. Therefore, the driver can always grasp the road surface condition more appropriately.

  In these cases, the reaction force variation means periodically varies the magnitude of the reaction force according to the magnitude of the operation amount of the braking operation means detected by the braking operation amount detection means, for example. In this case, the amplitude of the reaction force vibration may be changed, for example, by the braking operation amount detection means. It should be proportional to the amount of operation of the operating means. Further, in these cases, the amplitude of the reaction force vibration may change according to the frequency of the reaction force vibration generated by, for example, periodically changing the magnitude of the reaction force. More specifically, the amplitude of the reaction force vibration may be inversely proportional to the frequency of the reaction force vibration, for example.

  According to these, the amplitude of the reaction force vibration generated by periodically changing the magnitude of the reaction force depends on the amount of operation of the braking operation means (more specifically, based on a proportional relationship). Can change). Thereby, the driver can perceive the periodic fluctuation of the reaction force in the braking operation means more reliably. In addition, the amplitude of the reaction force vibration can be changed according to the vibration frequency (more specifically, based on the inversely proportional relationship). Accordingly, the driver can perceive the vibration of the reaction force due to the so-called 1 / f fluctuation through the braking operation means. Therefore, the driver can calmly and accurately brake the vehicle by perceiving comfortable vibrations.

  Another feature of the present invention is that the braking control means determines a total braking force required to brake the vehicle based on an operation amount of the braking operation means detected by the braking operation amount detection means. Total braking force determining means, and a control system that distributes the total braking force determined by the total braking force determining means to an electric braking force by the electric force generating means and a mechanical braking force by the braking force generating means. Power distribution means, and controls the electric force generation means and the braking force generation means based on the electrical braking force and the mechanical braking force distributed by the braking force distribution means. When the mechanical braking force periodically varies as the reaction force variation means periodically varies the magnitude of the reaction force, the braking force distribution means Periodic fluctuations Correspondingly, there is also possible to change the allocation of the electrical braking force in the total braking force.

  According to this, when the reaction force changing means periodically changes the mechanical braking force generated by the braking force generating means in order to periodically change the reaction force in the braking operation means, the braking force distribution means The distribution of the electric braking force by the generating means can be changed. Thereby, even in a situation where the mechanical braking force periodically increases or decreases, the total of the mechanical braking force and the electrical braking force is obtained by appropriately changing the distribution of the electrical braking force. A change in the total braking force can be effectively suppressed. Therefore, the driver can stably brake the vehicle while perceiving the vibration of the reaction force in the braking operation means.

  In this case, the braking force distribution means may change the distribution of the electrical braking force by an opposite phase with respect to the periodic fluctuation of the mechanical braking force, for example.

  According to this, even in a situation where the mechanical braking force periodically increases or decreases, the distribution of the electrical braking force is periodically changed by the opposite phase in accordance with the increase or decrease of the mechanical braking force. Thus, the electric braking force can be periodically decreased. Thereby, the change of the total braking force which is the sum total of mechanical braking force and electrical braking force can be suppressed more effectively. Therefore, the driver can brake the vehicle more stably while perceiving the vibration of the reaction force in the braking operation means.

1 is a schematic diagram schematically showing a configuration of a vehicle to which a vehicle braking control device of the present invention can be applied. It is a flowchart of the braking control program performed by the electronic control unit of FIG. (A) is a graph which shows the time change of request | requirement braking torque, (b) is a graph which shows the time change of total braking torque, (c) is a graph which shows the time change of reaction force F in a brake pedal. . It is a graph which shows the relationship between the required braking torque (depression force) and the amplitude in the fluctuation | variation (vibration) of reaction force. (A) is a graph which shows the time change of the request | required braking torque in the past, (b) is a graph which shows the time change of the conventional total braking torque, (c) is the time change of the reaction force in the conventional brake pedal. It is a graph which shows.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows the configuration of a vehicle Ve on which a vehicle braking control apparatus according to this embodiment is mounted.

  The vehicle Ve includes left and right front wheels 11 and 12 and left and right rear wheels 13 and 14. The motors 15 and 16 are incorporated in the wheels of the left and right front wheels 11 and 12, and the motors 17 and 18 are incorporated in the wheels of the left and right rear wheels 13 and 14, respectively. It is connected to the rear wheels 13 and 14 so that power can be transmitted. That is, the electric motors 15 to 18 are so-called in-wheel motors 15 to 18 and are disposed under the spring of the vehicle Ve together with the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14. Then, by independently controlling the rotation of the in-wheel motors 15 to 18, the driving force and the braking force generated on the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 can be independently controlled. It can be done.

  Each of these in-wheel motors 15 to 18 is constituted by, for example, an AC synchronous motor, and the inverter 19 converts the DC power of the power storage device 20 such as a battery or a capacitor into AC power. By being supplied to each in-wheel motor 15 to 18, each in-wheel motor 15 to 18 is driven (that is, powering), and driving torque is applied to the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14. The in-wheel motors 15 to 18 can be regeneratively controlled using the rotational energy of the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14. That is, during regeneration and power generation of each in-wheel motor 15-18, the rotational (kinetic) energy of the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 is converted into electric energy by each in-wheel motor 15-18. Is stored in the power storage device 20 via the inverter 19. At this time, electrical braking torque based on regenerative power is applied to the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14.

  Brake mechanisms 21, 22, 23, and 24 are provided between the wheels 11 to 14 and the corresponding in-wheel motors 15 to 18, respectively. Each brake mechanism 21-24 is well-known braking devices, such as a disc brake and a drum brake, for example. And these brake mechanisms 21-24 are each wheels 11-14 by the hydraulic pressure (hydraulic pressure) pumped from a master cylinder resulting from the depression operation of the brake pedal as a brake operation means which abbreviate | omits concrete illustration. Are connected to a brake actuator 25 that operates a piston and a brake shoe (both not shown) of a brake caliper that generates a mechanical braking force (braking torque).

  The inverter 19 and the brake actuator 25 include the rotation state of the in-wheel motors 15 to 18 (more specifically, the power running state or the regeneration state) and the operation state of the brake mechanisms 21 to 24 (more specifically, the brake release state or The electronic control unit 26 controls the braking state). Accordingly, the in-wheel motors 15 to 18, the inverter 19 and the power storage device 20 constitute the electric force generating means of the present invention, and the brake mechanisms 21 to 24 and the brake actuator 25 constitute the braking force generating means of the present invention. The control unit 26 constitutes the braking control means of the present invention.

  The electronic control unit 26 includes a microcomputer including a CPU, a ROM, a RAM, and the like as main components, and executes various programs including programs to be described later. For this reason, the electronic control unit 26 includes an accelerator sensor 27 that detects a driver's accelerator operation amount from an accelerator pedal depression amount (or angle, pressure, etc.), and a brake pedal depression force (or angle, pressure, etc.). Thus, signals from various sensors including a brake sensor 28 as a braking operation amount detecting means for detecting a driver's brake operation amount and a signal from the inverter 19 are input.

  As described above, when the sensors 27 and 28 and the inverter 19 are connected to the electronic control unit 26 and the signals are input, the electronic control unit 26 recognizes the traveling state of the vehicle Ve and detects the in-wheel motor. The operations of 15 to 18 and the brake mechanisms 21 to 24 can be controlled. Specifically, the electronic control unit 26 calculates a required driving force and a required braking force corresponding to the driver's accelerator operation amount and brake operation amount based on signals input from the accelerator sensor 27 and the brake sensor 28. be able to. In addition, the electronic control unit 26 is based on a signal input from the inverter 19 (for example, a signal indicating an electric energy or a current value supplied or regenerated during powering control or regenerative control of each in-wheel motor 15 to 18). The output torque (motor torque) of each in-wheel motor 15-18 can be calculated.

  As a result, the electronic control unit 26 outputs a signal for controlling the rotation of each of the in-wheel motors 15 to 18 via the inverter 19 and a signal for controlling the operation of each brake mechanism 21 to 24 via the brake actuator 25. can do. Therefore, the electronic control unit 26 obtains the required driving torque or the required braking torque based on the signals input from the accelerator sensor 27 and the brake sensor 28, and generates each required in-wheel motor so as to generate the required driving torque or the required braking torque. It is possible to control the running state of the vehicle Ve by outputting signals for controlling the power running / regenerative state of 15 to 18 and the brake release / braking state of the brake actuator 25, that is, the brake mechanisms 21 to 24, respectively.

  Next, the braking control by the electronic control unit 26 will be described in detail. In braking control of the vehicle Ve, the electronic control unit 26 (more specifically, the CPU) repeatedly executes the braking control program shown in FIG. 2 every predetermined short time. Specifically, the electronic control unit 26 starts execution of the braking control program in step S10, and determines in step S11 whether braking control is currently being executed. Here, as described above, the electronic control unit 26 determines whether the operation of the brake pedal (depression force, angle, pressure, etc.) by the driver represented by the signal input from the brake sensor 28 is as shown in FIG. The braking torque Tr required to brake the vehicle Ve (hereinafter referred to as the required braking torque Tr) is calculated so as to have the time change characteristics shown in FIG. The electronic control unit 26 performs regenerative control of the in-wheel motors 15 to 18 via the inverter 19 in order to generate the calculated required braking torque Tr on the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14. By controlling the electric braking torque (hereinafter referred to as braking torque Te) generated by each in-wheel motor 15 to 18 and the hydraulic pressure (hydraulic pressure) supplied to each brake mechanism 21 to 24 via the brake actuator 25 The total braking torque Tt calculated is generated by adding up the mechanical braking torque (hereinafter referred to as braking torque Tf) generated by each of the brake mechanisms 21 to 24. That is, the electronic control unit 26 realizes a total braking force determining means for determining the required braking torque Tr (that is, the total braking torque Tt), and the required braking torque Tr (that is, the total braking torque Tt) as the braking torque Te. A braking force distribution means for distributing torque to the braking torque Tf is realized.

  Therefore, if the total braking torque Tt is currently generated via the inverter 19 and the brake actuator 25, the electronic control unit 26 is currently executing the braking control. Therefore, the electronic control unit 26 determines “Yes” in step S11 and performs step S12. Proceed to On the other hand, if the total braking torque Tt is not generated via the inverter 19 and the brake actuator 25, the braking control is not being executed. Therefore, the electronic control unit 26 determines “No” in step S11 and proceeds to step S14. Then, the execution of the braking control program is temporarily terminated. Then, after the elapse of a predetermined short time, the electronic control unit 26 again starts executing the braking control program in step S10.

  In step S12, the electronic control unit 26 determines whether or not the magnitude of the required braking torque Tr calculated in step S11 is larger than a predetermined value To set in advance. That is, if the magnitude of the required braking torque Tr is greater than the predetermined value To, the electronic control unit 26 determines “Yes” and proceeds to step S13. On the other hand, if the magnitude of the required braking torque Tr is less than or equal to the predetermined value To, the electronic control unit 26 determines “No”, returns to step S11, and repeatedly executes the step processes of step S11 and step S12. Note that the magnitude of the predetermined value To may be set to a value smaller than the magnitude of the required braking torque Tra that requires the start of ABS control, as shown in FIG.

  In step S13, as shown in FIG. 4, the electronic control unit 26 is supplied to each brake mechanism 21-24 so as to have an amplitude A proportional to the magnitude of the required braking torque Tr calculated in step S11. The reaction force F in the brake pedal is periodically changed (vibrated) from the gentle braking to the sudden braking. Hereinafter, the periodic fluctuation (vibration) of the reaction force F will be specifically described.

  As described above, the hydraulic pressure supplied to each of the brake mechanisms 21 to 24 is generated due to the depression operation of the brake pedal by the driver, and the operation of the brake actuator 25 (more specifically, illustrated) It is increased or decreased by switching operation of various valves that are not. Therefore, the braking torque Tf generated by each of the brake mechanisms 21 to 24 is determined by the amount of operation of the brake pedal by the driver (depression force, angle, pressure, etc.). In other words, when the braking torque Tf is periodically changed (vibrated), the hydraulic pressure supplied to the brake mechanisms 21 to 24 is periodically changed (increased / decreased) in response to the fluctuation (vibration). The reaction force F at the brake pedal mechanically connected to each of the brake mechanisms 21 to 24 periodically fluctuates (vibrates). On the other hand, as described above, the required braking torque Tr necessary for braking the vehicle Ve is generated by the braking torque Te generated by the regenerative control of the in-wheel motors 15-18 and the brake mechanisms 21-24. This is realized by the sum of the braking torques Tf, that is, the total braking torque Tt.

  Therefore, the electronic control unit 26 maintains the magnitude of the required braking torque Tr (that is, the magnitude of the total braking torque Tt) and the magnitude of the braking torque Te by the in-wheel motors 15 to 18 and each brake mechanism 21. The hydraulic pressure supplied to each of the brake mechanisms 21 to 24 is periodically changed (vibrated), in other words, the reaction force at the brake pedal is periodically changed. Fluctuate (vibrate). In this case, as shown in FIG. 3B, the electronic control unit 26 controls the inverter 19 to change the amount of electric power regenerated from the in-wheel motors 15 to 18 by the frequency f. The braking torque Te by the motors 15 to 18 is changed (vibrated). At this time, when changing (vibrating) the braking torque Te, the electronic control unit 26 feels so-called human beings so that the magnitude of the amplitude A is inversely proportional to the frequency f as shown in FIG. The braking torque Te is changed (vibrated) so as to have a 1 / f fluctuation having a waveform.

  As described above, by changing (vibrating) the magnitude of the braking torque Te, the electronic control unit 26 maintains each magnitude of the required braking torque Tr (the magnitude of the total braking torque Tt). The magnitude of the braking torque Tf generated by 21 to 24 is changed (vibrated) so as to have an opposite phase to the change (vibration) of the braking torque Te and 1 / f fluctuation. That is, the electronic control unit 26 controls the brake actuator 25 so that the hydraulic pressure supplied to each of the brake mechanisms 21 to 24 is in a phase opposite to the change (vibration) of the braking torque Te and has 1 / f fluctuation. Change (vibrate) as follows. Accordingly, each of the brake mechanisms 21 to 24 can generate the braking torque Tf that changes (vibrates) so as to be in the opposite phase to the change (vibration) of the braking torque Te. It is possible to continue the magnitude of the total braking torque Tt obtained by adding the braking torque Te to match the magnitude of the required braking torque Tr. That is, as described above, even if the magnitude of the braking torque Tf and the magnitude of the braking torque Te are changed (vibrated) in opposite phases at the frequency f, the magnitude of the required braking torque Tr (that is, the total braking torque Tt) Size) can be maintained.

  On the other hand, when the braking torque Tf, that is, the hydraulic pressure by each of the brake mechanisms 21 to 24 is changed (vibrated) so as to have the frequency f and 1 / f fluctuation, as shown in FIG. The force F also changes (vibrates) to have a frequency f and 1 / f fluctuation. As a result, the driver can periodically cycle the reaction force F in the brake pedal in a situation where the magnitude of the required braking torque Tr is greater than the predetermined value To, in other words, in a situation where a predetermined deceleration occurs in the vehicle Ve. Variation can be perceived. For example, as shown in FIG. 3A, when the magnitude of the required braking torque Tr that increases with the passage of time increases to a torque Tra or higher at which ABS control is started, the electronic control unit 26 is changed to FIG. As shown in (b), the in-wheel motors 15 to 18 are regeneratively controlled via the inverter 19 to generate the braking torque Te so as to be constant from the fluctuating (vibrating) state. In addition, the electronic control unit 26 performs ABS control of each brake mechanism 21 to 24 via the brake actuator 25. At this time, as shown in FIG. 3C, the reaction force F of the brake pedal varies from the state fluctuated (vibrated) at the frequency f before the start of the ABS control as the ABS control starts. Since the state changes continuously to (vibrates), no sudden change occurs.

  Accordingly, the driver does not feel uncomfortable with the change in the reaction force F because the reaction force F of the brake pedal changes gently with the start of the ABS control. Further, the driver can predict that the ABS control is started by perceiving the fluctuation (vibration) of the reaction force F at the frequency f, and as a result, can accurately grasp the road surface condition. . Further, since the start of the ABS control can be predicted, the driver can calmly brake the vehicle Ve appropriately even in a situation where the ABS control is actually started.

  As described above, when the reaction force F is appropriately changed (vibrated), the electronic control unit 26 returns to step S12, and again executes step processes of step S12 and step S13.

  As can be understood from the above description, according to the present embodiment, the electronic control unit 26 regeneratively controls the in-wheel motors 15 to 18 (electric brake devices) via the inverter 19 to provide the braking force Te. And the brake mechanisms 21 to 24 (mechanical brake devices) are controlled via the brake actuator 25 to generate the braking force Tf to brake the vehicle Ve. At this time, the electronic control unit 26 determines the required braking torque determined according to the magnitude of the brake pedal operation amount (depressing force, angle, pressure, etc.) by the driver (specifically, based on the brake pedal operation amount). The magnitude of the reaction force F in the brake pedal can be periodically varied according to the magnitude of the deceleration generated in the vehicle, that is, the magnitude of Tr is larger than a predetermined value To set in advance. . Therefore, the driver can perceive a periodic variation in the magnitude of the reaction force F through the brake pedal when the vehicle Ve is braked by operating the brake pedal larger than a certain brake pedal operation amount. Thereby, the electronic control unit 26 feels uncomfortable with respect to the fluctuation of the reaction force F due to the start of the ABS control, for example, by periodically changing the magnitude of the reaction force F before the ABS control is started. There is nothing.

  Further, since the magnitude of the reaction force F at the brake pedal can be periodically changed before the start of the ABS control, for example, the driver can predict whether or not the ABS control is started. Therefore, the driver can appropriately grasp the road surface state and can calmly brake the vehicle even when the ABS control is started.

  Further, by periodically changing the magnitude of the hydraulic pressure supplied to each of the brake mechanisms 21 to 24, the reaction force F in the brake pedal mechanically connected to the brake mechanisms 21 to 24 via the brake actuator 25. The magnitude of can be changed periodically. Therefore, the magnitude of the reaction force in the brake pedal can be periodically changed more reliably. Further, even in a situation where each in-wheel motor 15-18 mainly generates the braking force Te, the magnitude of the reaction force F is periodically changed by periodically changing the braking force Tf of each brake mechanism 21-24. Therefore, the driver can always grasp the road surface condition more appropriately.

  Further, the amplitude A of the vibration of the reaction force F generated by periodically changing the magnitude of the reaction force F depends on the magnitude of the brake pedal operation amount (specifically, the depression force) based on the proportional relationship. Can be changed. As a result, the driver can perceive the periodic fluctuation of the reaction force F in the brake pedal more reliably. Further, the amplitude A of the vibration of the reaction force F can be changed according to the frequency f of the vibration based on the inversely proportional relationship. Thus, the driver can perceive the vibration of the reaction force F due to the so-called 1 / f fluctuation through the brake pedal. Therefore, the driver can calmly and accurately brake the vehicle by perceiving comfortable vibrations.

  Further, in order to periodically vary the reaction force F, even in a situation where the braking force Tf by each of the brake mechanisms 21 to 24 increases or decreases, each in-wheel motor 15 has an opposite phase according to the increase or decrease of the braking force Tf. The braking force Te due to -18 can be reduced. Thereby, the change of the total braking force Tt which is the sum total of braking force Tf and braking force Te can be suppressed more effectively. Therefore, the driver can more stably brake the vehicle Ve while perceiving the vibration of the reaction force F at the brake pedal.

  In carrying out the present invention, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the object of the present invention.

  For example, in the above embodiment, assuming that the vehicle Ve is traveling on a high μ road, the ABS control start time is relatively late, in other words, the required braking torque Tr is larger than the preset torque Tra. When carried out to be executed. In this case, for example, when the vehicle Ve travels on a low μ road such as a snowy road, the ABS control start time is relatively early, in other words, the torque Tra is set to a small value and executed. Thus, when the vehicle Ve travels on a low μ road, the electronic control unit 26, for example, in a situation where the ABS control is executed a plurality of times at an early stage, step S12 of the braking control program shown in FIG. The predetermined value To is determined by setting a smaller value, and the reaction force F in the brake pedal is periodically changed at an early stage. Thereby, even if the road surface μ changes, the driver can easily grasp the road surface state by periodically changing the reaction force F in the brake pedal. Therefore, even in this case, the same effect as the above embodiment can be obtained.

  Moreover, in the said embodiment, based on the total braking torque Tt being the sum total of the braking torque Te by each in-wheel motor 15-18, and the braking torque Tf by each brake mechanism 21-24, the electronic control unit 26 is an inverter. 19, the in-wheel motors 15 to 18 are regeneratively controlled to periodically change the braking force Te, thereby periodically changing the braking torque Tf by the brake mechanisms 21 to 24. As a result, in the brake pedal It implemented so that the magnitude | size of the reaction force F might be fluctuate | varied periodically. In this case, the electronic control unit 26 can directly and periodically vary the braking torque Tf by the brake mechanisms 21 to 24 via the brake actuator 25 to periodically vary the magnitude of the reaction force F. Needless to say. Even in this case, the same effect as the above embodiment can be obtained.

  In the above embodiment, the vibration amplitude A of the reaction force F is proportional to the required braking torque Tr (or stepping force). In this case, the amplitude A of the vibration of the reaction force F may have any relationship with the magnitude of the required braking torque Tr (or stepping force), for example, the magnitude of the required braking torque Tr (or stepping force). In contrast, the vibration amplitude A of the reaction force F may be assumed to be constant. In the above embodiment, the vibration amplitude A of the reaction force F is inversely proportional to the frequency f, that is, 1 / f. In this case, the amplitude A of the vibration of the reaction force F may have any relationship with the frequency f. For example, the amplitude A of the vibration of the reaction force F may be constant with respect to the frequency f. . In these cases, although the periodic fluctuation of the magnitude of the reaction force F may be perceived by the driver differently from the above embodiment, the same effect as the above embodiment can be expected.

  Furthermore, in the above embodiment, the periodic fluctuation of the braking torque Te by the in-wheel motors 15 to 18 and the periodic fluctuation of the braking torque Tf by the brake mechanisms 21 to 24 are in opposite phases to each other, The reaction force F was periodically varied so that the total braking torque Tt was not affected. In this case, only the braking torque Tf by each of the brake mechanisms 21 to 24 can be periodically changed, that is, the braking torque Te by each of the in-wheel motors 15 to 18 can be changed periodically. is there. Further, in this case, the braking torque Te by the in-wheel motors 15 to 18 is not periodically changed in a strictly opposite phase with respect to the periodic fluctuation of the braking torque Tf by the brake mechanisms 21 to 24. It is also possible to do. In these cases, although the total braking torque Tt slightly fluctuates due to the periodic fluctuation of the braking torque Tf, the magnitude of the reaction force F at the brake pedal can be periodically varied, so that the same effect as in the above embodiment is obtained. Can be expected.

  DESCRIPTION OF SYMBOLS 11, 12 ... Front wheel, 13, 14 ... Rear wheel, 15, 16, 17, 18 ... Electric motor (in-wheel motor), 19 ... Inverter, 20 ... Power storage device, 21, 22, 23, 24 ... Brake mechanism, 25 ... Brake actuator, 26 ... electronic control unit, 27 ... accelerator sensor, 28 ... brake sensor, Ve ... vehicle

Claims (9)

A braking operation amount detection means for detecting an operation amount of a braking operation means which is applied to a vehicle having an electric force generation means for generating a driving force or a braking force on at least a wheel and is operated by a driver to brake the vehicle; A braking force generating means for generating a braking force on the wheel rotated by the electric force generating means, and the electric force corresponding to an operation amount of the braking operation means detected by the braking operation amount detecting means. A braking control device for a vehicle, comprising: a generating means; and a braking control means for controlling a braking force generated by each of the braking force generating means.
The braking control means
When the electric force generating means and the braking force generating means generate a braking force, the braking force is applied to the braking operation means according to the magnitude of the operation amount of the braking operation means detected by the braking operation amount detection means. A braking control device for a vehicle, comprising reaction force variation means for periodically varying the magnitude of a reaction force against a driver's operation. The vehicle braking control device according to claim 1,
The braking force generation means is mechanically connected to the braking operation means, and generates a braking force to be applied to the wheels due to an operation on the braking operation means by a driver.
The reaction force fluctuation means is
A braking control device for a vehicle, wherein the braking force applied to the wheels by the braking force generating means is periodically changed to periodically change the magnitude of the reaction force. In the vehicle braking control device according to claim 2,
The braking force generating means is
A braking control device for a vehicle, which generates a braking force in accordance with a hydraulic pressure generated when a driver operates the braking operation means. In the braking control device for a vehicle according to any one of claims 1 to 3,
The reaction force fluctuation means is
According to the magnitude of the operation amount of the braking operation means detected by the braking operation amount detection means, the amplitude of the reaction force vibration generated by periodically varying the magnitude of the reaction force is changed. A braking control device for a vehicle characterized by the above. In the vehicle braking control device according to claim 4,
The vibration amplitude of the reaction force is
A braking control device for a vehicle, which is proportional to the magnitude of the operation amount of the braking operation means detected by the braking operation amount detection means. In the braking control device for a vehicle according to claim 4 or 5,
The vibration amplitude of the reaction force is
A braking control device for a vehicle, which changes according to a frequency of vibration of the reaction force generated by periodically changing the magnitude of the reaction force. In the vehicle brake control device according to claim 6,
The vibration amplitude of the reaction force is
A braking control apparatus for a vehicle, wherein the braking control apparatus has an inversely proportional relationship with a frequency of the reaction force vibration. The vehicle braking control device according to any one of claims 1 to 7,
The braking control means
Total braking force determining means for determining a total braking force required for braking the vehicle based on an operation amount of the braking operation means detected by the braking operation amount detecting means;
Braking force distribution means for distributing the total braking force determined by the total braking force determination means to an electrical braking force by the electric force generation means and a mechanical braking force by the braking force generation means; ,
Controlling the electric force generation means and the braking force generation means based on the electrical braking force and the mechanical braking force distributed by the braking force distribution means,
When the mechanical braking force periodically fluctuates as the reaction force fluctuation means periodically fluctuates the magnitude of the reaction force,
The braking control device for a vehicle, wherein the braking force distribution means changes the distribution of the electrical braking force in the total braking force in response to a periodic fluctuation of the mechanical braking force. In the vehicle braking control device according to claim 8,
The braking force distribution means includes
A braking control device for a vehicle, wherein the distribution of the electrical braking force is changed by an opposite phase with respect to the periodic fluctuation of the mechanical braking force.

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