JP6488215B2 - Braking device for vehicle - Google Patents

Description

  The present invention relates to a vehicle braking device that generates a braking force in a vehicle such as an electric vehicle or a hybrid vehicle.

  For example, vehicles such as electric vehicles and hybrid vehicles are equipped with a vehicle braking device that generates a braking force generated by a hydraulic braking torque or a regenerative braking torque. In such a vehicle braking device, hydraulic braking control and regenerative braking control are performed in order to control the braking force generated in the vehicle. Further, in order to obtain a braking force according to a braking operation by a driver while considering energy saving, a cooperative control technique is known in which hydraulic braking control and regenerative braking control are coordinated (see, for example, Patent Document 1). ).

In the coordinated control technique according to Patent Document 1, the regenerative braking force by the regenerative braking control is preferentially applied when obtaining the target braking force based on the braking request by the driver. When the target braking force cannot be achieved only by the regenerative braking force by the regenerative braking control, the cooperative control is performed so that the shortage is compensated by the hydraulic braking force by the hydraulic braking control.
Here, during the braking operation by the driver, for example, it is assumed that a transient sudden change in the regenerative braking torque occurs due to an increase in the brake pedal. At this time, if the regenerative braking force is insufficient with respect to the target braking force, control is performed to increase the hydraulic braking force so as to compensate for the shortage. Then, there is a concern that the feeling related to the operation of the brake pedal is deteriorated.

Therefore, in the coordinated control technology according to Patent Document 1, when a transient sudden change in the regenerative braking torque occurs due to an increase in the brake pedal, a filter process is performed on the sudden change in the regenerative braking torque, The cooperative control is performed based on the regenerative braking torque having a dull response characteristic.
According to the coordinated control technique according to Patent Document 1, even when a transient regenerative braking torque suddenly changes, the feeling change related to the brake pedal operation can be sufficiently mitigated, and the braking operation feeling is improved by the driver. So that it does not give a sense of incongruity.

JP2011-259541A

  However, in the cooperative control technique according to Patent Document 1, filter processing is performed on the suddenly changed regenerative braking torque, and the above-described cooperative control is performed based on the regenerative braking torque that dulls the response characteristics after the filter processing. When the sudden change occurs, the amount of regeneration is reduced by increasing the dependence on the hydraulic braking force by the amount that the response characteristic of the regenerative braking torque is dulled, resulting in a problem that the regeneration efficiency is impaired.

  The present invention has been made to solve the above problems, and provides a braking device for a vehicle that can satisfactorily maintain a braking operation feeling and regenerative efficiency during cooperative control in which hydraulic braking control and regenerative braking control are coordinated. The purpose is to provide.

In order to achieve the above object, the invention according to (1) includes a hydraulic braking unit that generates a hydraulic braking force on a vehicle, a regenerative braking unit that generates a regenerative braking force on the vehicle, and a braking operation amount by a driver. The sum of the calculation unit for calculating the time differential value , the hydraulic braking force by the hydraulic braking unit, and the regenerative braking force by the regenerative braking unit follows the target braking force based on the driver's braking operation. A control unit that performs coordinated control of the hydraulic braking force and the regenerative braking force and performs control to limit the regenerative braking force, and the control unit has a larger time differential value of the braking operation amount, The most important feature is that the degree of limiting the regenerative braking force is relaxed .

According to the invention of (1), the control unit, the larger the time differential value of the amount of braking operation, in order to alleviate the degree of limiting the regenerative braking force, coordinated to coordinate the regenerative braking control and the hydraulic braking control The braking operation feeling and the regeneration efficiency during control can be maintained well.

The invention according to (2) is the vehicular braking apparatus according to the invention according to (1), wherein the control unit is at the time of an initial stage braking operation and the time differentiation of the amount of braking operation is performed. The larger the value , the less the degree of limiting the regenerative braking force.

According to the invention of (2), the control unit is a braking operation of the initial stage, and the greater the time differential value of the amount of braking operation, in order to alleviate the degree of limiting the regenerative braking force, the braking operation The braking operation feeling and the regenerative efficiency during the cooperative control in which the hydraulic braking control and the regenerative braking control are coordinated can be satisfactorily maintained in the initial braking operation stage with a high probability that the time differential value of the amount becomes large. .

The invention according to (3) is the vehicle braking device according to the invention according to (1) or (2) , wherein the limitation of the regenerative braking force limits a time variation rate related to the regenerative braking force. It is performed by doing.

According to the invention according to (3) , since the limitation of the regenerative braking force is performed by limiting the time variation rate related to the regenerative braking force, compared to the case of simply limiting the magnitude of the regenerative braking force, When a sudden change in the regenerative braking torque occurs, it is possible to expect the effect of maintaining the braking operation feeling and the regenerative efficiency appropriately and satisfactorily.

  According to the present invention, it is possible to satisfactorily maintain the braking operation feeling and the regeneration efficiency during the cooperative control in which the hydraulic braking control and the regenerative braking control are coordinated.

It is a figure showing the example which mounts the vehicle braking device which concerns on embodiment of this invention in the electric vehicle. It is a lineblock diagram showing the outline of the brake device for vehicles concerning the embodiment of the present invention. It is a block diagram showing the periphery structure of ESB-ECU, VSA-ECU, and PDU which the vehicle braking device which concerns on embodiment of this invention has. It is a flowchart figure with which it uses for operation | movement description of the braking device for vehicles which concerns on embodiment of this invention. It is a time chart used for operation | movement description of the braking device for vehicles which concerns on a comparative example. It is a time chart figure which uses for operation | movement description of the vehicle braking device which concerns on embodiment of this invention. It is a time chart figure used for operation | movement description of the vehicle braking device which concerns on a reference example.

Hereinafter, a vehicle braking device according to an embodiment of the present invention will be described in detail with reference to the drawings.
In addition, in the figure shown below, the common referential mark shall be attached | subjected between the members which have a common function, or between the members which have a mutually corresponding function. Further, for convenience of explanation, the size and shape of the member may be schematically represented by being deformed or exaggerated.

[Example of mounting the vehicle braking device 11 according to the embodiment of the present invention to the electric vehicle V]
First, an example of mounting a vehicle braking device 11 according to an embodiment of the present invention on an electric vehicle V will be described with reference to FIG.

  Prior to the description according to the embodiment of the present invention, reference will be made to a rule for assigning symbols used for convenience of description. In the vehicle brake device 11 according to the embodiment of the present invention, for example, a common member may be provided on each of the four wheels because of being mounted on the four-wheeled electric vehicle V, for example. In this case, a common code is assigned between the common members, and the suffix FL is added after the code of the member provided on the left front wheel in the traveling direction, and the code of the member provided on the right front wheel. Subscript FR is added after the symbol, the suffix RL is appended after the symbol of the member provided on the left rear wheel, and the suffix RR is appended after the symbol of the member provided on the right rear wheel. Further, when generically referring to common members, subscripts may be omitted.

  The vehicle braking device 11 according to the embodiment of the present invention is configured so that a hydraulic pressure is generated through an electric circuit in addition to an existing braking device that generates a hydraulic braking torque (synonymous with a hydraulic braking force) through a hydraulic circuit. A By Wire type braking device that generates braking torque is provided. As shown in FIG. 1, the vehicle braking device 11 is mounted on an electric vehicle (corresponding to a “vehicle” of the present invention) V.

  As shown in FIG. 1, the electric vehicle V is provided with a third electric motor 92 for driving wheels. For convenience of explanation, the first electric motor 72 and the second electric motor 82 will be described later. A front wheel drive shaft 15A is connected to the third electric motor 92 via a power transmission mechanism (not shown). Wheels (front wheels) 17FL and 17FR are provided at both ends of the front wheel drive shaft 15A. Similarly, wheels (rear wheels) 17RL and 17RR, which are driven wheels, are provided at both ends of the rear wheel driven shaft 15B.

  A PDU (Power Drive Unit) 33 for driving control, which will be described later, controls the third electric motor 92 to the power running state, thereby using the third electric motor 92 as an electric motor that is intended for use and outputting a power running torque. It has a function to make it. As a result, the third electric motor 92 acts to drive the wheels 17FL and 17FR.

In addition, the PDU 33 controls the third electric motor 92 to be in a regenerative state, thereby using the third electric motor 92 as a generator different from the original application and outputting a regenerative braking torque (synonymous with regenerative braking force). It has a function to make it. As a result, the third electric motor 92 acts to brake the wheels 17FL and 17FR.
That is, the vehicle braking device 11 according to the embodiment of the present invention is configured to be able to use both the hydraulic braking torque and the regenerative braking torque in order to perform the braking control of the electric vehicle V.

  The electric vehicle V is equipped with a vehicle battery (not shown) that functions as a power source for the third electric motor 92. As the in-vehicle battery, for example, a lithium ion secondary battery can be suitably used.

  As shown in FIG. 1, the third electric motor 92 is connected to the inverter 19. The inverter 19 is connected to the in-vehicle battery via an energization cable (not shown). The inverter 19 has a function of converting the regenerative power (AC power) of the third electric motor 92 into DC power while converting DC power from the in-vehicle battery into AC power.

  Specifically, when the third electric motor 92 is used as the electric motor, direct current power from the in-vehicle battery is converted into alternating current power by the inverter 19, and this alternating current power is supplied to the third electric motor 92. On the other hand, when the third motor 92 is used as a generator, the regenerative power (AC power) from the third motor 92 is converted into DC power by the inverter 19, and this DC power is supplied to the in-vehicle battery. The Further, the torque and rotation speed of the third electric motor 92 can be controlled by controlling the current value and frequency of the AC power using the inverter 19. The inverter 19, the PDU 33, and the third electric motor 92 correspond to the “regenerative braking unit” of the present invention.

  The electric vehicle V is provided with hydraulic braking mechanisms 24FL to 24RR for braking the wheels 17FL to 17RR. The hydraulic braking mechanisms 24FL to 24RR correspond to the “hydraulic braking unit” of the present invention. The hydraulic braking mechanisms 24FL to 24RR include a braking hydraulic pressure generating device 26 that generates hydraulic pressure related to braking according to a depression amount (braking operation amount) of the brake pedal 12 (see FIG. 2) by the driver, It includes calipers 27FL to 27RR that brake the wheels 17FL to 17RR by the hydraulic pressure generated by the hydraulic pressure generator 26.

  In the example shown in FIG. 1, a disc brake device is employed as the hydraulic braking mechanism 24, but the present invention is not limited to this example. As the hydraulic braking mechanism 24, a drum brake device may be employed instead of the disc brake device.

  In order to perform drive control of the electric vehicle V, the electric vehicle V is provided with a PDU 33 as shown in FIG. The configuration of the PDU 33 will be described later in detail.

  Further, in order to stabilize the behavior of the electric vehicle V, the electric vehicle V is provided with a VSA (Vehicle Stability Assist; VSA is a registered trademark) -ECU 31 as shown in FIG. The configuration of the VSA-ECU 31 will be described later in detail.

  Further, in order to control the operation state of the hydraulic braking mechanism 24 and the like, the electric vehicle V is provided with an ESB (Electrical Servo Brake) -ECU 29 as shown in FIG. The configuration of the ESB-ECU 29 will be described later in detail.

  The ESB-ECU 29, the VSA-ECU 31 and the PDU 33 are connected to each other via a communication medium 35 so as to be able to communicate with each other as shown in FIG. As the communication medium 35, for example, a CAN (Controller Area Network) constructed in the electric vehicle V can be suitably used. CAN is a multiplexed serial communication network used for information communication between in-vehicle devices. CAN has excellent data transfer speed and error detection capability. Hereinafter, an example in which the CAN communication medium 35 is used as a communication network built in the electric vehicle V will be described.

  In the vehicle braking device 11 according to the embodiment of the present invention, the regenerative braking control related to the third electric motor 92 is controlled by the hydraulic braking related to the brake hydraulic pressure generating device 26 in order to earn electric energy obtained by regeneration. It is applied with priority over control. Here, “the regenerative braking control related to the third electric motor 92 is preferentially applied compared to the hydraulic braking control related to the brake hydraulic pressure generating device 26” means that the regenerative braking related to the third electric motor 92 is performed. The braking torque obtained by using the hydraulic braking control related to the brake hydraulic pressure generator 26 is determined by applying the control preferentially, and the shortage of the braking torque obtained by using the regenerative braking control related to the third electric motor 92 is determined by It means to make up.

[Configuration of Vehicle Braking Device 11 According to an Embodiment of the Present Invention]
Next, the configuration of the vehicle braking device 11 according to the embodiment of the present invention will be described with reference to FIGS. 2 and 3.
The vehicle braking device 11 includes a hydraulic pressure generating device 14 shown in FIG. 2, and a first braking device 21, a second braking device 23, and a third braking device 25 shown in FIG. . The hydraulic pressure generator 14 has a function of accepting a braking operation by the driver by the master cylinder 34 through the brake pedal 12 (see FIG. 2). The first braking device 21 and the second braking device 23 correspond to the braking fluid pressure generating device 26.

  The first braking device 21 includes a motor cylinder device 16, an ESB-ECU 29, and a first electric motor 72. As shown in FIG. 2, the motor cylinder device 16 includes first and second slave pistons 88 a and 88 b, and at least liquid that accompanies the operation of the first electric motor 72 based on an electric signal corresponding to a braking operation by the driver. It has a function of generating hydraulic braking torque by pressure.

  The second braking device 23 includes a vehicle stability assist device 18 (hereinafter abbreviated as “VSA device 18”, where VSA is a registered trademark), a VSA-ECU 31, and a second electric motor 82. Has been. The VSA device 18 controls the hydraulic pressure related to the hydraulic braking by driving the pump (see FIG. 2) 135 in accordance with the operation of the second electric motor (see FIGS. 2 and 3) 82 based on the electric signal according to the behavior of the vehicle. Has the function to increase. By exhibiting such functions, the VSA device 18 has an ABS function for preventing wheel lock during braking operation, a TCS (traction control system) function for preventing wheel slipping during acceleration, and a function for suppressing side slip during turning. Have

  The third braking device 25 includes a PDU 33, an inverter 19, and a third electric motor 92.

As shown in FIG. 2, each of the hydraulic pressure generation device 14, the motor cylinder device 16, and the VSA device 18 is connected to each other via piping tubes 22 a to 22 f through which brake fluid flows.
The hydraulic pressure generating device 14 and the motor cylinder device 16 constituting the by-wire type braking device are electrically connected to the ESB-ECU 29 (see FIGS. 1 and 3) via an electric wire (not shown). Further, the VSA device 18 is electrically connected to the VSA-ECU 31 (see FIGS. 1 and 3) via an electric wire (not shown). The internal configuration of the hydraulic pressure generator 14 and the motor cylinder device 16 will be described later in detail.

Reference numerals Pm, Pp, and Ph are brake fluid pressure sensors that detect the brake fluid pressure generated in each part of the piping tubes 22a to 22f.
The other elements indicated by reference numerals in FIG. 2 are not directly related to the present invention, and thus the description thereof is omitted. However, the other elements are cited in the description of the action described later.

[Basic operation of vehicle braking device 11]
Next, the basic operation of the vehicle braking device 11 will be described.
In the vehicle braking device 11, when the first braking device 21 including the ESB-ECU 29 (see FIGS. 1 and 3) that mainly controls the motor cylinder device 16 and the by-wire is operating normally, the driver can use the brake pedal 12. When the pedal is depressed, a so-called by-wire braking device is activated.

  Specifically, in the vehicle braking device 11 during normal operation, when the driver depresses the brake pedal 12, the first cutoff valve 60a and the second cutoff valve 60b are liquids that brake the master cylinder 34 and each wheel. The calipers 27FL to 27RR of the hydraulic braking mechanisms 24FL to 24RR are operated using the brake hydraulic pressure generated by the motor cylinder device 16 in a state where the communication with the pressure braking mechanisms 24FL to 24RR is cut off.

  For this reason, the vehicle braking device 11 is, for example, a vehicle such as an electric vehicle (including a fuel cell vehicle), a hybrid vehicle, or the like that generates little negative pressure in the internal combustion engine or has no negative pressure generated by the internal combustion engine. Or it can apply suitably for the vehicle without an internal combustion engine itself.

  Incidentally, during normal operation, the first cutoff valve 60a and the second cutoff valve 60b are shut off, while the third cutoff valve 62 is opened. At this time, when the brake pedal 12 is depressed, the brake fluid flows from the master cylinder 34 into the stroke simulator 64. For this reason, even if the 1st cutoff valve 60a and the 2nd cutoff valve 60b are interrupted | blocked, since the flow of the brake fluid from the master cylinder 34 to the stroke simulator 64 arises, a stroke will arise in the brake pedal 12. FIG.

  On the other hand, in the vehicle brake device 11, when the driver depresses the brake pedal 12 when the first brake device 21 does not operate normally, the existing hydraulic brake device becomes active. Specifically, in the vehicular braking device 11 at the time of abnormality (the power supply voltage is shut down), when the driver depresses the brake pedal 12, the first cutoff valve 60a and the second cutoff valve 60b are opened. And the third shutoff valve 62 is closed to transmit the brake hydraulic pressure generated in the master cylinder 34 to the hydraulic brake mechanisms 24FL to 24RR, and the calipers 27FL to 24H of the hydraulic brake mechanisms 24FL to 24RR. Operate 27RR.

[Functional Block Configuration of Vehicle Braking Device 11 According to Embodiment of the Present Invention]
Next, a functional block configuration of the vehicle braking device 11 according to the embodiment of the present invention will be described with reference to FIG.

[Configuration of ESB-ECU 29]
As shown in FIG. 3, the ESB-ECU 29 includes, as an input system, an ignition key switch (hereinafter abbreviated as “IG key switch”) 121, a vehicle speed sensor 123, a brake pedal sensor 125, a hall sensor 127, and a brake. Hydraulic pressure sensors Pm and Pp are connected to each other.

  However, the switches and sensors listed as the input system connected to the ESB-ECU 29 may not be directly connected to the ESB-ECU 29. Specifically, for example, with respect to the vehicle speed sensor 123, the vehicle speed sensor 123 as an input system is directly connected to the ESB-ECU 29 if information on the vehicle body speed (hereinafter abbreviated as “vehicle speed”) can be acquired. You don't need to be.

  The IG key switch 121 is a switch that is operated when supplying a power supply voltage to each part of the electrical components mounted on the electric vehicle V via an in-vehicle battery (not shown). When the IG key switch 121 is turned on, the power supply voltage is supplied to the ESB-ECU 29 and the ESB-ECU 29 is activated. The vehicle speed sensor 123 has a function of detecting the vehicle speed of the electric vehicle V. Information relating to the vehicle speed detected by the vehicle speed sensor 123 is sent to the ESB-ECU 29.

The brake pedal sensor 125 has a function of detecting the amount of operation (stroke amount) and weight (stepping force) of the brake pedal 12 by the driver. Information relating to the operation amount and weighting of the brake pedal 12 detected by the brake pedal sensor 125 is sent to the ESB-ECU 29.
However, the brake pedal sensor 125 may be a brake SW having a function of simply detecting ON (depressed) / OFF (not depressed).

  The hall sensor 127 has a function of detecting the rotation angle of the first electric motor 72 (current position information in the axial direction of the slave pistons 88a and 88b). Information regarding the rotation angle of the first electric motor 72 detected by the hall sensor 127 is sent to the ESB-ECU 29.

  The brake fluid pressure sensors Pm and Pp have a function of detecting the upstream fluid pressure of the first cutoff valve 60a and the downstream fluid pressure of the second cutoff valve 60b in the brake fluid pressure system, respectively. The fluid pressure information of each part in the brake fluid pressure system detected by the brake fluid pressure sensors Pm and Pp is sent to the ESB-ECU 29.

  On the other hand, as shown in FIG. 3, the ESB-ECU 29 is connected with the first electric motor 72 and the first to third shut-off valves 60a, 60b, 62 as output systems.

  As shown in FIG. 3, the ESB-ECU 29 includes a first information acquisition unit 71, a speed correlation value calculation unit (corresponding to a “calculation unit” of the present invention) 73, a target braking torque calculation unit 75, and a first 1 braking control section 77 (corresponding to a part of the “control section” of the present invention) 77.

  The first information acquisition unit 71 includes information relating to the on / off operation of the IG key switch 121, information relating to the vehicle speed detected by the vehicle speed sensor 123, braking operation amount detected by the brake pedal sensor 125, and braking relating to weighting. It has a function of acquiring operation information, rotation angle information related to the first electric motor 72 detected by the hall sensor 127, information related to the brake hydraulic pressure of each part detected by the brake hydraulic pressure sensors Pm and Pp, and the like.

  The speed correlation value calculation unit 73 has a function of calculating the time differential value dVb / dt of the braking operation amount based on the braking operation amount detected by the brake pedal sensor 125 and the braking operation information related to the weight. The time differential value dVb / dt of the braking operation amount corresponds to the “speed correlation value related to the braking operation” of the present invention. Further, the speed correlation value calculating unit 73 adds the time differential value dVb / dt of the braking operation amount to the reference value dVrf used as a reference when limiting the time variation rate related to the regenerative braking torque, thereby generating the regenerative braking. It has a function of calculating an index value dV used as a final index when limiting the time variation rate related to torque.

  Here, the index value dV becomes larger as the time differential value dVb / dt of the braking operation amount becomes larger, in other words, as the speed related to the braking operation becomes steeper. When the index value dV becomes a large value, the degree of limiting the time variation rate related to the regenerative braking torque is relaxed with respect to the reference value dVrf. The index value dV calculated by the speed correlation value calculation unit 73 is sent to the first braking control unit 77.

  The target braking torque calculation unit 75 basically has a function of calculating a target braking torque corresponding to a required braking amount based on the braking operation amount of the brake pedal 12. Further, the target braking torque calculation unit 75 distributes the calculated target braking torque to the target hydraulic braking torque and the target regenerative braking torque. In this distribution, the target braking torque calculation unit 75 obtains the target regenerative braking torque with reference to the degree of limiting the time variation rate related to the regenerative braking torque, and then subtracts the target regenerative braking torque from the target braking torque. Then, a target hydraulic braking torque is obtained. Next, the target braking torque calculation unit 75 sends the target hydraulic braking torque to the first braking control unit 77, while the target braking torque is transmitted to the third braking control unit of the PDU 33 via the CAN communication medium 35. Send to 175.

  Basically, the first braking control unit 77 is configured so that the sum of the hydraulic braking torque and the regenerative braking torque follows the target braking torque based on the driver's braking operation. It has a function to perform cooperative control of braking torque. Further, the first braking control unit 77 has a function of performing a control for limiting the regenerative braking torque, specifically, limiting the time variation rate related to the regenerative braking torque. Further, the first braking control unit 77 has a function of reducing the degree of limiting the time variation rate related to the regenerative braking torque as the time differential value dVb / dt of the braking operation amount is larger.

  More specifically, the first braking control unit 77 has an index value dV calculated by the speed correlation value calculating unit 73, which is used as a final index when limiting the time variation rate related to the regenerative braking torque, is determined in advance. A threshold value dVth to be exceeded, and, as a result of this determination, when it is determined that the index value dV exceeds the threshold value dVth, the time variation rate related to the regenerative braking torque is limited. The degree is set to a relaxed value with respect to the reference value dVrf. The first braking control unit 77 executes cooperative control based on the regenerative braking torque having the set time variation rate.

  The ESB-ECU 29 is configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. This microcomputer reads out and executes programs and data stored in the ROM, and has various information acquisition functions, a function of calculating a time differential value dVb / dt of the braking operation amount, and a target braking torque that the ESB-ECU 29 has. To perform execution control related to various functions, including a function for performing calculation control and distribution function, a function for performing cooperative control of hydraulic braking torque and regenerative braking torque, and a function for performing control for limiting the time variation rate related to regenerative braking torque. Operate.

[Configuration of VSA-ECU 31]
As shown in FIG. 3, a wheel speed sensor 150, an accelerator pedal sensor 151, a yaw rate sensor 152, a G sensor 153, a steering angle sensor 155, and a brake fluid pressure sensor Ph are connected to the VSA-ECU 31, respectively.

  The wheel speed sensors 150FL to 150RR have a function of detecting the rotational speed (wheel speed) for each of the wheels 17FL to 17RR. Information relating to the rotational speed of each of the wheels 17FL to 17RR detected by the wheel speed sensors 150FL to 150RR is sent to the VSA-ECU 31.

  The accelerator pedal sensor 151 has a function of detecting the amount of operation (stroke amount) of the accelerator pedal by the driver. Information related to the operation amount of the accelerator pedal detected by the accelerator pedal sensor 151 is sent to the VSA-ECU 31.

  The yaw rate sensor 152 has a function of detecting the yaw rate occurring in the host vehicle. Information related to the yaw rate detected by the yaw rate sensor 152 is sent to the VSA-ECU 31.

  The G sensor 153 has a function of detecting the longitudinal G (longitudinal acceleration) and lateral G (lateral acceleration) generated in the electric vehicle V, respectively. Information about the front and rear G and the lateral G detected by the G sensor 153 is sent to the VSA-ECU 31.

  The steering angle sensor 155 has a function of detecting information related to the steering angle including the steering amount and steering direction of the steering. Information related to the steering angle of the steering detected by the steering angle sensor 155 is sent to the VSA-ECU 31.

  The brake fluid pressure sensor Ph has a function of detecting the brake fluid pressure in the VSA device 18 in the brake fluid pressure system. Of the brake fluid pressure system detected by the brake fluid pressure sensor Ph, fluid pressure information in the VSA device 18 is sent to the VSA-ECU 31.

  On the other hand, as shown in FIG. 3, the second electric motor 82 is connected to the VSA-ECU 31 as an output system.

  The VSA-ECU 31 has an ABS control function. The ABS control function means a function of avoiding the locking of the wheels 17FL to 17RR through the braking control of the VSA device 18.

  The VSA-ECU 31 includes a second information acquisition unit 161, a slip information calculation unit 163, and a second braking control unit 167.

The second information acquisition unit 161 includes information relating to the rotational speed (wheel speed) for each of the wheels 17FL to 17RR detected by the wheel speed sensors 150FL to 150RR, and acceleration / deceleration of the accelerator pedal detected by the accelerator pedal sensor 151. Information on the operation amount, information on the yaw rate generated in the vehicle detected by the yaw rate sensor 152, information on the front and rear G and side G generated in the vehicle detected by the G sensor 153, the steering angle sensor 155 Information on the steering angle detected in step S3, and hydraulic pressure information on the hydraulic system in the VSA device 18 detected by the brake hydraulic pressure sensor Ph.
The second information acquisition unit 161 has a function of acquiring information related to the vehicle speed by the vehicle speed sensor 123 sent from the ESB-ECU 29 via the CAN communication medium 35.

  The slip information calculation unit 163 is based on the information on the vehicle speed acquired by the second information acquisition unit 161 and the information on the rotation speed (wheel speed) for each wheel 17FL to 17RR when the electric vehicle V is traveling. It has a function of calculating a slip ratio (slip information) for each of the wheels 17FL to 17RR by calculation. Information relating to the slip ratio for each of the wheels 17FL to 17RR obtained by the slip information calculation unit 163 is appropriately referred to when the second braking control unit 167 determines whether or not the start condition of the ABS control is successful.

  The second braking control unit 167 basically determines whether or not the ABS control start condition is satisfied based on information related to the slip ratio for each of the wheels 17FL to 17RR obtained by the slip information calculation unit 163. When it is determined that the ABS control start condition is satisfied as a result of the determination, the second braking control unit 167 controls the brake fluid by the VSA device 18 so as to suppress the slip of each of the wheels 17FL to 17RR. By exerting the pressure adjusting function, it operates to perform the braking control for each of the wheels 17FL to 17RR.

[Configuration of PDU 33]
As shown in FIG. 3, the PDU 33 includes a third information acquisition unit 171 and a third braking control unit (corresponding to a part of the “control unit” of the present invention) 175. Yes.

  As shown in FIG. 3, the third information acquisition unit 171 receives information related to the accelerator pedal acceleration / deceleration operation amount detected by the accelerator pedal sensor 151 and information related to establishment of the ABS control start condition as VSA−. It has the function to acquire via ECU31 and the CAN communication medium 35, respectively. The information related to the acceleration / deceleration operation amount of the accelerator pedal acquired by the third information acquisition unit 171 is appropriately referred to when setting the power running torque of the third electric motor 92 in the third braking control unit 175. .

  Further, as shown in FIG. 3, the third information acquisition unit 171 has a function of acquiring information related to the target regenerative braking torque via the ESB-ECU 29 and the CAN communication medium 35. The information related to the target regenerative braking torque is obtained when the third braking control unit 175 performs control to generate the regenerative braking torque by driving the third electric motor 92 as a generator so as to follow the target regenerative braking torque. As appropriate.

  The third braking control unit 175 includes information related to the vehicle speed detected by the vehicle speed sensor 123, information related to the acceleration / deceleration operation amount of the accelerator pedal acquired by the third information acquisition unit 171, and information related to the range position. Based on the above, the power running torque map of the third electric motor 92 is set with reference to a predetermined power running torque map.

  In addition, the third braking control unit 175 performs the third braking control so that the regenerative braking torque acting on the electric vehicle V follows the target regenerative braking torque sent from the target braking torque calculating unit 75 of the ESB-ECU 29. It operates so as to perform control for generating regenerative braking torque by driving the electric motor 92 as a generator.

[Operation of Vehicle Braking Device 11 According to Embodiment of the Present Invention]
Next, the operation of the vehicle braking device 11 according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a flowchart for explaining the operation of the vehicle braking device 11 according to the embodiment of the present invention.

  In step S <b> 11, the first information acquisition unit 71 acquires various pieces of information including the braking operation amount detected by the brake pedal sensor 125 and the braking operation information related to the weight.

  In step S12, the speed correlation value calculation unit 73 calculates the time differential value dVb / dt of the braking operation amount based on the braking operation information detected by the brake pedal sensor 125 every moment.

  In step S13, the speed correlation value calculation unit 73 performs the time differential value dVb / dt of the braking operation amount calculated in step S12 with respect to the reference value dVrf used as a reference when limiting the time variation rate related to the regenerative braking torque. Is added to calculate an index value dV used as a final index when the time variation rate related to the regenerative braking torque is limited.

  In step S14, the first braking control unit 77 determines whether or not the index value dV exceeds a predetermined threshold value dVth. If it is determined in step S14 that the index value dV does not exceed the threshold value dVth (No in step S14), the first braking control unit 77 advances the process flow to step S15. Make it. On the other hand, when it is determined that the index value dV exceeds the threshold value dVth (Yes in Step S14), the first braking control unit 77 jumps the process flow to Step S16.

  In step S15, the first braking control unit 77 sets the degree of limiting the time variation rate related to the regenerative braking torque to the reference value dVrf. As the reference value dVrf, a value based on verification by experiment or simulation may be set as appropriate.

  On the other hand, in step S16, the first braking control unit 77 sets the degree of limiting the time variation rate related to the regenerative braking torque to a value (index value dV) that is less than the reference value dVrf.

  In step S17, the first braking control unit 77 executes cooperative control based on the regenerative braking torque with the time variation rate set in step S15 or step S16.

  Next, the operation of the vehicle braking device 11 according to the embodiment of the present invention will be described with reference to FIGS. 5A and 5B. FIG. 5A is a time chart for explaining the operation of the vehicle braking device according to the comparative example. FIG. 5B is a time chart for explaining the operation of the vehicle brake device 11 according to the embodiment of the present invention.

First, the operation of the vehicle braking device according to the comparative example will be described. The vehicle braking device according to the comparative example is a device to which the cooperative control technology according to Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-259541) is applied.
The electric vehicle V is in a constant speed running state during the period immediately before time t0 to t1 in FIG. 5A (see FIG. 5A (a)). In the same period, the value of the braking torque requested by the driver is zero (see FIG. 5A (b)). Similarly, the values of the regenerative braking torque and the hydraulic braking torque are also zero (see FIGS. 5A (c) and 5 (d)).

  At time t1 in FIG. 5A, the driver performed a sharp braking operation (see FIG. 5A (b)). In response to this, the vehicle braking apparatus according to the comparative example performs a filter process on the suddenly changed regenerative braking torque as described below, and performs cooperative control based on the regenerative braking torque that dulls the response characteristics after the filter process. Do.

  During the period from time t1 to time t2 in FIG. 5A, the value of the requested braking torque by the driver is maintained at T1 (see FIG. 5A (b)). In the same period, the value of the regenerative braking torque rises linearly from zero to T1 (see FIG. 5A (c)). On the other hand, the value of the hydraulic braking torque falls linearly from T1 to zero contrary to the characteristics of the regenerative braking torque (see FIG. 5A (d)). As a result, during the same period, the electric vehicle V is in a decelerating running state (see FIG. 5A (a)).

  In the period after time t2 in FIG. 5A, the value of the requested braking torque by the driver continues to be T1 (see FIG. 5A (b)). In the same period, the value of the regenerative braking torque is also maintained at T1, as is the value of the required braking torque (see FIG. 5A (c)). The value of the hydraulic braking torque is zero (see FIG. 5A (d)). As a result, during the same period, the electric vehicle V continues to maintain the deceleration traveling state (see FIG. 5A (a)).

Next, the operation of the vehicle braking device 11 according to the embodiment of the present invention will be described.
In the period immediately before time t0 to t11 in FIG. 5B, the electric vehicle V is in a constant speed traveling state (see FIG. 5B (a)). During the same period, the value of the required braking torque by the driver is zero (see FIG. 5B (b)). Similarly, the values of the regenerative braking torque and the hydraulic braking torque are also zero (see FIGS. 5B (c) and (d)).

  At time t11 in FIG. 5B, a sharp braking operation is performed by the driver (see FIG. 5B (b)). In response to this, the first braking control unit 77 of the vehicle braking device 11 according to the embodiment of the present invention increases the regenerative braking torque as the time differential value dVb / dt of the braking operation amount increases as described below. The degree of limiting the time variation rate is relaxed (including a mode of releasing the limitation of the time variation rate related to the regenerative braking torque), and cooperative control is performed based on the set regenerative braking torque of the time variation rate. In the example shown in FIG. 5B, an example is shown in which the first braking control unit 77 of the vehicle braking device 11 releases the restriction on the time variation rate related to the regenerative braking torque (no restriction).

  In the period after time t11 in FIG. 5B, the value of the required braking torque by the driver is maintained at T1 (see FIG. 5B (b)). In the same period, the value of the regenerative braking torque is also maintained at T1, as is the value of the required braking torque (see FIG. 5B (c)). This is because the restriction on the time variation rate related to the regenerative braking force is released. The value of the hydraulic braking torque is zero (see FIG. 5B (d)). As a result, during the same period, the electric vehicle V maintains a decelerating traveling state (see FIG. 5B (a)).

[Effects of the vehicle braking device 11 according to the embodiment of the present invention]
Next, the effect of the vehicle braking device 11 according to the embodiment of the present invention will be described.
The vehicle braking device 11 based on the first aspect (corresponding to claim 1) includes a hydraulic braking mechanism (hydraulic braking unit) 24FL to 24RR that generates a hydraulic braking force on the electric vehicle (vehicle) V, and an electric vehicle. The inverter 19, the PDU 33, and the third electric motor 92 (regenerative braking unit) that generate the regenerative braking force on V, and the speed correlation value calculation unit (calculation) that calculates the time differential value dV b / dt of the braking operation amount by the driver. Part) 73, the hydraulic braking force by the hydraulic braking unit, and the sum of the regenerative braking force by the regenerative braking unit follow the target braking force based on the driver's braking operation. A first braking control unit 77 and a third braking control unit 175 (control unit) that perform control to limit the regenerative braking force (limit the time variation rate related to the regenerative braking force) while performing cooperative control. Prepare. The control unit relaxes the degree of limiting the regenerative braking force (limiting the time variation rate related to the regenerative braking force) as the time differential value dVb / dt of the braking operation amount increases .

According to the vehicle braking device 11 based on the first aspect, the control unit limits the regenerative braking force as the time differential value dVb / dt of the braking operation amount increases (limits the time variation rate related to the regenerative braking force). to) in order to mitigate the degree, it is possible to maintain good braking operation feeling and regeneration efficiency at the cooperative control for coordinating and controlling regenerative braking and the hydraulic braking control.

Further, the vehicle braking device 11 based on the second aspect (corresponding to claim 2 ) is the vehicle braking device 11 based on the first aspect, and the control unit is in the initial stage of the braking operation, And the degree which restrict | limits the said regenerative braking force (The time variation rate which concerns on a regenerative braking force) is eased, so that the time differential value dVb / dt of braking operation amount is large. Here, the time of the braking operation in the initial stage means a period in which an operation of starting to depress the brake pedal 12 is performed after the occupant's foot is separated from the brake pedal 12.

According to the vehicle braking device 11 based on the second aspect , the control unit limits the regenerative braking force as the braking operation amount is increased and the time differential value dVb / dt of the braking operation amount is larger. In order to alleviate the degree of performing (restricting the time fluctuation rate related to the regenerative braking force), the hydraulic braking control and the regenerative braking control are performed at the initial braking operation stage where the speed correlation value related to the braking operation is likely to increase. The braking operation feeling and the regenerative efficiency at the time of cooperative control for coordinating can be maintained well.

The third aspect vehicular brake system 11 based on (claim 3 corresponding to) is a vehicular brake system 11 based on the first or second aspect, the regenerative braking force limit, the regenerative braking It is configured to be performed by limiting the time variation rate related to power.

According to the vehicular braking apparatus 11 based on the third aspect , the regenerative braking force is limited by limiting the time fluctuation rate related to the regenerative braking force, and thus the magnitude of the regenerative braking force is simply limited. Compared to the case, when a sudden change in the regenerative braking torque occurs, it is possible to expect the effect of maintaining the braking operation feeling and the regenerative efficiency appropriately and satisfactorily.

[Reference examples (all or a part are incorporated into the examples as necessary)]
Incidentally, for example, in addition to the above-described braking operation in the initial stage (when the brake pedal 12 is first depressed), there is a scene in which the required braking torque increases. That is when the brake pedal 12 is further depressed when the brake pedal 12 is further depressed during the depression operation.
At the time of the braking operation in the initial stage, the required braking torque is satisfied by the hydraulic braking torque. When the required braking torque increases as the brake pedal 12 is increased, the required braking is mainly performed by the regenerative braking torque. Assume a case where torque is provided (hydraulic braking torque is used as an auxiliary).

The operation of the vehicle braking device in the case of the reference example will be described with reference to FIG. FIG. 6 is a time chart for explaining the operation of the vehicle braking device according to the reference example.
In the case of the above reference example, the hydraulic braking torque corresponding to the gradually reduced amount is subtracted from the required braking torque on the premise that the hydraulic braking torque is gradually reduced (so that the driver does not feel uncomfortable during the braking operation). The braking torque of the magnitude is provided by the regenerative braking torque. However, it is known that the magnitude of the regenerative braking torque that can be generated using the third electric motor 92 varies from moment to moment depending on the state of charge of the storage battery that stores the regenerative power, the gear position state, and the like.

  The electric vehicle V is in a constant speed running state during the period immediately before time t0 to t21 in FIG. 6 (see FIG. 6A). During the same period, the value of the requested braking torque by the driver is zero (see FIG. 6B). Similarly, the values of the regenerative braking torque and the hydraulic braking torque are also zero (see FIGS. 6C and 6D).

  At time t21 in FIG. 6, the driver performed a sharp braking operation (required braking torque value: T2) (see FIG. 6B). In response to this, the vehicle braking apparatus according to the reference example performs the braking control so as to satisfy the required braking torque value T2 by the hydraulic braking torque. As a result, at the same time t21, the value of the hydraulic braking torque rises steeply from zero to T2 (see FIG. 6D).

  In the period immediately before time t21 to t22 in FIG. 6, the required braking torque value by the driver is maintained at T2 (see FIG. 6B). During the same period, the value of the regenerative braking torque is maintained at zero (see FIG. 6C). On the other hand, the value of the hydraulic braking torque is maintained at T2 (see FIG. 6 (d)). As a result, during the same period, the electric vehicle V is in a decelerating running state (see FIG. 6A).

  During the period from time t22 to time t23 in FIG. 6, the driver performs an additional stepping braking operation (final required braking torque value: T3) (see FIG. 6B). In response, the vehicle braking apparatus according to the reference example covers the required braking torque value T3 mainly by the regenerative braking torque during the period from time t22 to time t24 in FIG. 6 (hydraulic braking torque is used as an auxiliary). The braking control is performed as follows.

  More specifically, the time-dependent characteristic of the required braking torque by the driver shows a characteristic of maintaining T3 in the period after time t23 after linearly rising from T2 to T3 in the period from time t22 to t23. (See FIG. 6 (b)).

  In the period from time t22 to t24 in FIG. 6, the time-dependent characteristic of the hydraulic braking torque gradually decreases linearly from T2 to zero, and then maintains zero in the period after time t24 (FIG. 6 ( d)). Note that the time variation rate (time differential value of the hydraulic braking torque) characteristic of the hydraulic braking torque in the period from time t22 to t24 is, for example, an uncomfortable feeling related to the braking operation when the hydraulic braking torque decreases. A characteristic set in advance may be adopted in consideration of the fact that the driver will not be held.

In the period from time t22 to t24 in FIG. 6, the time-dependent characteristic of the regenerative braking torque is the hydraulic braking torque in the period from time t22 to t24 from the time-dependent characteristic of required braking torque in the period to time t22 to t24. Is obtained by subtracting the time-dependent characteristic (see FIG. 6C). However, the time-dependent characteristic of the regenerative braking torque is limited to a range below the upper limit characteristic of the regenerative braking torque that can be generated by the third electric motor 92 (see FIG. 6C).
In short, the time-dependent characteristic of the regenerative braking torque does not exceed the upper limit of the regenerative braking torque that can be generated by the third electric motor 92, does not make the driver feel uncomfortable with the braking operation, and regenerative efficiency. The characteristic is set in consideration of various points to keep it as good as possible.

In other words, in the vehicle braking device according to the reference example, the time variation rate of the hydraulic braking torque set in consideration of not causing the driver to feel uncomfortable with the braking operation (FIG. 6D). Reference) and the time variation rate related to the increase in the required braking torque (the time variation rate of the portion exceeding T2 in the period from time t22 to t23 in FIG. 6B) integrated. And the time-dependent characteristic of the regenerative braking torque is set by using the smaller time fluctuation rate of the regenerative braking torque that can be generated by the third electric motor 92 (see FIG. 6C).
Thereby, according to the vehicle braking apparatus according to the reference example, it is possible to expect an effect of maintaining a good braking operation feeling and regenerative efficiency during cooperative control in which hydraulic braking control and regenerative braking control are coordinated. .

[Other Embodiments]
The plurality of embodiments described above show examples of realization of the present invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by these. This is because the present invention can be implemented in various forms without departing from the gist or main features thereof.

  For example, in the embodiment according to the present invention, each of the ESB-ECU 29, the VSA-ECU 31, and the PDU 33 has been described by way of an example in which information can be mutually exchanged via the CAN communication medium 35. The invention is not limited to this example. You may employ | adopt the structure which collects the various function parts which ESB-ECU29, VSA-ECU31, and PDU33 have in one ECU. In this case, for example, various function units including the information acquisition unit and the braking control unit may be configured to aggregate the respective functions.

  In the embodiment according to the present invention, the example in which the vehicle braking device 11 according to the embodiment of the present invention is applied to the electric vehicle V equipped with the third electric motor 92 as a power source has been described. The present invention is not limited to this example. The present invention may be applied to a hybrid vehicle equipped with a third electric motor 92 and a reciprocating engine as a power source.

  In the embodiment according to the present invention, an example of changing the degree of limiting the time variation rate related to the regenerative braking force based on the time differential value of the braking operation amount (speed correlation value related to the braking operation) dVb / dt. Although described above, the present invention is not limited to this example. The present invention changes the distribution amount and / or distribution ratio of the hydraulic braking force and the regenerative braking force based on the time differential value of the braking operation amount (speed correlation value related to the braking operation) dVb / dt (for example, the braking operation). In the case where the speed correlation value is large, a configuration in which the distribution amount and / or distribution ratio of the regenerative braking force to the hydraulic braking force is increased (restriction of the regenerative braking force) may be employed. You may employ | adopt the structure which sets the magnitude | size of a hydraulic braking force to zero.

11 Vehicle braking device 19 Inverter (regenerative braking unit)
24FL-24RR Hydraulic braking mechanism (hydraulic braking part)
33 PDU (Regenerative braking unit)
73 Speed correlation value calculation unit (calculation unit)
77 First braking control unit (control unit)
92 3rd electric motor (regenerative braking part)
175 Third braking control unit (control unit)
V Electric car (vehicle)

Claims (3)

A hydraulic braking unit for generating hydraulic braking force on the vehicle;
A regenerative braking unit for generating a regenerative braking force in the vehicle;
A calculation unit for calculating a time differential value of the braking operation amount by the driver;
Coordination of the hydraulic braking force and the regenerative braking force so that the sum of the hydraulic braking force by the hydraulic braking unit and the regenerative braking force by the regenerative braking unit follows a target braking force based on the braking operation of the driver. A control unit that performs control and performs control to limit the regenerative braking force,
The vehicular braking apparatus , wherein the controller reduces the degree of limiting the regenerative braking force as the time differential value of the braking operation amount increases . The vehicle braking device according to claim 1,
The vehicular braking apparatus characterized in that the control unit relaxes the degree of limiting the regenerative braking force as the time differential value of the braking operation amount is larger at the time of the initial braking operation. The vehicle braking device according to claim 1 or 2 ,
The regenerative braking force is limited by limiting a time variation rate related to the regenerative braking force.

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