JP4428162B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device mounted on a vehicle equipped with a motor.

  Conventionally, a vehicle in which a motor is mounted on each of the left and right wheels of the front wheel or the rear wheel is known. This motor applies driving force according to the state of the vehicle to assist in running the vehicle, or applies braking force by regeneration to charge the battery when the vehicle decelerates (during braking). Be controlled.

  Brake control is known in which the braking force by the motor (hereinafter referred to as “regenerative braking force”) and the braking force by the friction brake (hereinafter referred to as “friction brake braking force”) are coordinated. Yes. For example, Patent Document 1 describes a control device that improves braking performance by cooperating mechanical antilock brakes and electrical braking (such as a motor). Further, Patent Document 2 is configured to reliably obtain a required braking force while using both regenerative braking by a motor and braking by a friction brake, and can promote energy recovery by regenerative braking. A control device is described.

  Further, Patent Document 3 describes a regenerative cooperative brake control device that eliminates deficiency or excess of total braking torque and can smoothly connect braking torque by a motor even when regenerative coordination is canceled. Patent Document 4 describes a control device that prevents overcharging of a battery due to regenerative braking of a motor.

JP-A-6-327101 JP-A-8-163707 JP 2000-24503 A JP 2000-102116 A

  However, in the control device described in Patent Documents 1 to 3, for example, the temperature of the motors provided on the left and right wheels, the amount of charge of the battery, and the like are not taken into consideration. Hereinafter, there is a case where a desired output cannot be obtained from the motor due to a difference in torque that can be output from the left and right wheel motors. For this reason, the vehicle may not be able to accelerate efficiently during re-acceleration after braking.

  The present invention has been made in order to solve such problems. The object of the present invention is to provide a braking force by a friction brake so that a desired driving force can be obtained from the motor at the time of reacceleration after braking. An object of the present invention is to provide a brake control device capable of distributing the braking force or driving force of a motor to front, rear, left and right wheels.

In one aspect of the present invention, a brake control device mounted on a vehicle includes a motor that independently drives and regenerates left and right wheels of the vehicle, a friction brake that is provided on each of the left and right wheels, and a vehicle state of the vehicle. Vehicle state acquisition means for acquiring the distribution, and distribution derivation means for deriving distribution of the braking force or driving force of the motor and the braking force of the friction brake to each of the left and right wheels based on the acquired vehicle state And a control means for outputting a braking force or a driving force corresponding to the derived distribution from the motor and the friction brake, and the vehicle state acquisition means is for charging a battery for supplying electric power to the motor. Gets the amount, the allocation deriving means, when the charging amount of the battery exceeds a predetermined value, thereby deriving the distribution so as to power running of the motor, when the motor is powering The driving force to be output, determines the distribution so as to offset the braking force of the friction brake.

The above brake control device is mounted on a vehicle or the like. The brake control device includes a motor and a friction brake. The motor is driven by electric power supplied from a battery or the like, and independently applies a driving force by power running or a braking force by regeneration to the front wheels or the left and right wheels of the rear wheels. The friction brake also applies a braking force independently to the left and right wheels of the front wheel or the rear wheel. That is, the brake control device performs control based on the torque generated by the motor and the torque generated by the friction brake. Furthermore, the brake control device includes vehicle state acquisition means for acquiring a vehicle running state and a vehicle state such as a motor and a battery. The brake control device has distribution derivation means for deriving distribution of the braking force or driving force of the motor and the braking force of the friction brake to each of the left and right wheels based on such a vehicle state.
Specifically, the distribution deriving means derives the distribution so that the motor is powered when the charge amount of the battery exceeds a predetermined value. When the amount of charge of the battery is large (overcharged state or the like), further charging of the battery by regeneration of the motor may cause a decrease in battery performance. Therefore, when the battery is in an overcharged state, the brake control device does not regenerate the motor in order to prevent the battery from being charged further, and further, the power of the battery is consumed by powering the motor. Prevent overcharge. Further, since the motor is powered during braking, when the vehicle accelerates after braking, the vehicle can be immediately given a desired driving force by the motor.
The distribution deriving means determines the distribution so that the driving force output when the motor is powered is canceled by the braking force of the friction brake. That is, the driving force output by the motor is balanced by the braking force output by the friction brake. Thus, the brake control device can perform appropriate brake control even though the motor applies driving force to the vehicle during braking.
“Deriving distribution” means, for example, obtaining the above-mentioned distribution with reference to a predetermined map, etc., calculating the above-mentioned distribution using a predetermined arithmetic expression, etc., or combining both of them. Including.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
First, a brake control device according to a first embodiment of the present invention will be described.

(Vehicle configuration)
Below, the schematic structure of the vehicle which concerns on 1st Embodiment is demonstrated using FIG. FIG. 1 is a block diagram illustrating a schematic configuration of a vehicle 100 according to the present embodiment. In FIG. 1, the left side of the drawing shows the front of the vehicle 100, and the right side of the drawing shows the rear of the vehicle 100.

  The vehicle 100 includes an engine 1, left and right front wheels 3fL and 3fR, left and right rear wheels 3rL and 3rR, a battery 5, inverters 6 and 21, a controller 7, a brake system 8, a brake pedal 11, and a brake pedal operation. A quantity sensor 13 and a motor 20 are provided. The wheels 3fL, 3fR, 3rL, and 3rR are respectively provided with motors 4fL, 4fR, 4rL, and 4rR. The motors 4fL, 4fR, 4rL, and 4rR have temperature sensors 12fL, 12fR, 12rL, 12rR is provided for each. Furthermore, the wheels 3fL, 3fR, 3rL, 3rR are provided with friction brakes 9fL, 9fR, 9rL, 9rR, respectively, and angular velocity sensors 10fL, 10fR, 10rL, 10rR are also provided respectively. A power generation motor 20 is connected to the engine 1.

  In the following description, for the components arranged symmetrically in the front-rear direction, “f” and “r” are added to the reference numerals when the front-rear distinction is necessary, and “f” when the front-rear distinction is unnecessary. , “R” is omitted. Similarly, regarding the components arranged symmetrically, “L” and “R” are added to the reference numerals when the left and right distinction is necessary, and “L” and “R” when the right and left distinction is not necessary. Is omitted. Therefore, when “f”, “r”, “L”, and “R” added to the code are omitted, all of the front, rear, left, and right are included.

  The engine 1 is an internal combustion engine that generates power by exploding an air-fuel mixture in a combustion chamber. A vehicle 100 shown in FIG. 1 is of an engine front type. As the engine 1, a gasoline engine, a diesel engine, or the like can be used. The vehicle 100 may not have the engine 1. In that case, a drive source such as a fuel cell may be used instead of the engine 1. In addition, it is not essential for the vehicle 100 to have the engine 1, and the present invention may be applied to an electric vehicle (Electric Vehicle) having a drive source such as an electric motor. Further, a fuel cell may be used as a drive source instead of the engine 1.

  The motor 4 is provided independently for the front, rear, left and right wheels 3. The motor 4 applies a driving force or a regenerative braking force to the front, rear, left and right wheels 3. That is, the vehicle 100 is configured so that the motor 4 can independently power and regenerate the front, rear, left and right wheels 3.

  Electric power charged in the battery 5 is supplied to the motor 4 via the inverter 6. As a result, the motor 4 applies driving force to the front, rear, left and right wheels 3. Further, the motor 4 supplies power generated by regeneration to the battery 5 via the inverter 6. In this case, the motor 4 applies a regenerative braking force to the front, rear, left and right wheels 3. In FIG. 1, power is exchanged between the motor 4 and the inverter 6 as indicated by arrows S7fL, S7fR, S7rL, and S7rR.

  The temperature sensor 12 is provided in the motor 4 described above. The temperature sensor 12 detects the temperature of the motor 4 provided on each of the front, rear, left and right wheels 3. Then, signals S9fL, S9fR, S9rL, and S9rR corresponding to the temperature of the motor 4 detected by the temperature sensor 12 are supplied to the controller 7.

  The battery 5 is a secondary battery such as a lead storage battery or a nickel metal hydride battery, and exchanges power with the inverter 6 as indicated by an arrow S6. A signal S2 corresponding to the capacity of the battery 5 (that is, the charge amount) is acquired by the controller 7.

  The inverter 6 is a device that mainly controls the amount of generated power, and is connected to the battery 5 and the motor 4 through a power cable or the like. When receiving power from the battery 5, the inverter 6 converts it into a three-phase AC voltage suitable for the motor 4 to drive. The inverter 6 supplies the converted three-phase AC voltage to the motor 4 and drives each motor 4 independently. The drive control of the motor 4 by the inverter 6 is performed based on a control signal S4 from the controller 7. Further, when the inverter 6 receives supply of electric power generated from the motor 4 when the vehicle 100 is decelerated, the inverter 6 converts the electric power into a DC voltage suitable for charging the battery 5 to charge the battery 5. Do.

  The battery 5 is charged when the engine 1 drives the motor 20 as necessary. In this case, the electric power generated by driving the motor 20 is supplied to the inverter 21 as shown by an arrow S10a, and the inverter 21 supplies this electric power to the battery 5 as shown by an arrow 10b.

  The brake system 8 is configured by a hydraulic system. The brake system 8 includes a master cylinder and a hydro unit (not shown). As shown by an arrow S31, the operation of the brake pedal 11 by the driver, that is, the brake pressure is transmitted to the brake system 8. The brake system 8 controls the brake pressure from the brake pedal 11 based on the control signal S5 supplied from the controller 7 to operate the friction brake 9. In this case, the brake system 8 transmits the hydraulic pressure to the friction brake 9 through an oil passage indicated by arrows S8fL, S8fR, S8rL, and S8rR.

  The brake pedal operation amount sensor 13 detects the operation amount (that is, the depression amount) of the brake pedal 11 by the driver. Then, the brake pedal operation amount sensor 13 supplies the controller 7 with a signal S32 corresponding to this operation amount. The controller 7 can acquire the operation amount of the brake pedal 11 and also the depression speed of the brake pedal 11. The controller 7 supplies a control signal S5 to the brake system 8 based on the signal S32, the traveling state of the vehicle 100, and the like. Details of the control of the brake system 8 by the controller 7 will be described later.

  The friction brake 9 is constituted by a drum brake, a disc brake or the like. The friction brake 9 is driven by hydraulic pressure supplied from the brake system 8 and applies braking force to the front, rear, left and right wheels 3. In this case, the friction brake 9 applies a braking force according to the value of the hydraulic pressure supplied from the brake system 8 to the front, rear, left and right wheels 3.

  The angular velocity sensor 10 is provided on each of the front, rear, left and right wheels 3. The angular velocity sensor 10 detects an angular velocity (rotational speed) of rotation of the front, rear, left and right wheels 3. Then, the angular velocity sensor 10 supplies signals S1fL, S1fR, S1rL, and S1rR corresponding to the detected angular velocities to the controller 7.

  The controller 7 includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like. The controller 7 determines a braking force (hereinafter referred to as “required braking force”) to be individually applied to the front, rear, left and right wheels 3 based on the signal S32 supplied from the brake pedal operation amount sensor 13. Further, the controller 7 acquires a signal S1 supplied from the angular velocity sensor 10, a signal S2 supplied from the battery 5, and a signal S9 supplied from the temperature sensor 12. In the present embodiment, the controller 7 determines the braking force (that is, “regenerative braking force”) due to regeneration of the motor 4 based on these acquired amounts (hereinafter, these acquired amounts are also referred to as “vehicle state”). ) And the braking force (ie, “friction brake braking force”) distribution by the friction brake 9 is derived for each of the left and right wheels 3f and 3r. Specifically, the controller 7 derives the distribution of both braking forces so that a desired driving force can be obtained from the motor 4 when the vehicle 100 is accelerated again after braking. That is, the controller 7 performs control so that the output of the motor can be efficiently obtained at the time of reacceleration after braking. Thereby, the vehicle 100 can obtain the maximum output from the motor 4 at the time of reacceleration after braking, and can accelerate quickly and efficiently. As described above, the controller 7 functions as vehicle state acquisition means for acquiring the vehicle state of the vehicle 100 and distribution derivation means for deriving the distribution of the regenerative braking force of the motor 4 and the braking force of the friction brake 9. In this case, as a derivation method, the controller 7 obtains the above-mentioned distribution by referring to, for example, a predetermined map, or calculates the above-mentioned distribution using a predetermined arithmetic expression, or a combination of both. To obtain the above allocation.

  Furthermore, the controller 7 according to the present embodiment acquires the temperature of the motor 4, sets the temperature of the motor 4 provided on the left and right wheels 3f, 3r to a predetermined temperature, and distributes both braking forces so as not to cause a temperature difference. To derive. More specifically, when the temperature of the motor 4 becomes a predetermined value or more, the controller 7 suppresses heat generation of the motor 4 by reducing the regenerative braking force of the motor 4. As a result, only the temperature of the motor 4 on one side of the left and right wheels 3f and 3r will not exceed a predetermined value. Therefore, since the desired output can be obtained by the left and right wheel motors 4 during acceleration after braking, the vehicle 100 can perform further efficient acceleration.

  The motor 4, the battery 5, the inverter 6, the controller 7, the brake system 8, the friction brake 9, the angular velocity sensor 10, the temperature sensor 12, and the brake pedal operation amount sensor 13 constitute a brake control device.

(Configuration of controller)
Next, the configuration of the controller 7 according to the present embodiment and the processing performed by the controller 7 will be described.

  First, the basic concept of control performed by the controller 7 according to the present embodiment will be described with reference to FIG. FIG. 2 shows a braking force applied to the vehicle 100 at the time of turning (hereinafter, when simply used as “braking force”, it means a force that is a combination of “friction brake braking force” and “regenerative braking force”). A schematic diagram when given is shown. In addition, the vehicle 100 has shown what the front wheel 3f can steer. In addition, for convenience of explanation, a case where braking force is applied only to the left and right wheels 3f of the front wheels will be described.

  As shown in FIG. 2, the vehicle 100 is turning in the direction (left direction) indicated by the arrow A3. Since the vehicle 100 is turning, the angular speeds of the left and right wheels of the front wheel 3f are different. Specifically, the angular velocity of the right wheel 3fR serving as the outer wheel during turning is greater than that of the left wheel 3fL serving as the inner wheel. In general, it is known that the motor tends to decrease the output torque as the angular velocity of the wheel increases. Therefore, during left turn, the regenerative braking force by the motor 4fR provided on the right wheel 3fR is reduced.

  Here, the regenerative braking force that can be obtained from the motor 4 f depends on the capacity (charge amount) of the battery 5. Therefore, if the capacity of the battery 5 is small, it is necessary to rely on the friction brake braking force rather than the regenerative braking force when the vehicle 100 is braked. On the contrary, if the capacity of the battery 5 is large, the regenerative braking force can be greatly used.

  As described above, it is understood that it is necessary to apply a braking force to the vehicle 100 in consideration of the turning direction of the vehicle 100, the capacity of the battery 5, and the like. Therefore, in consideration of such points, it is preferable to derive the distribution of the friction brake braking force and the regenerative braking force applied to the vehicle 100 to both the left and right wheels 3f.

  Next, adverse effects that occur when there is a difference in the temperature of the motor 4f between the left and right wheels 3f will be described. During the brake control of the vehicle 100, there may be a difference in the temperature of the motor 4f of the left and right wheels 3f. This temperature difference is caused by a difference in angular velocity between the left and right wheels 3f during turning, a difference in the amount of radiant heat received from the engine 1, and the brake control of the left and right wheels 3f independently. If a difference in the temperature of the motor 4f occurs between the left and right wheels 3f as described above, a difference occurs in the driving force that can be output from the motor 4f of the left and right wheels 3f during re-acceleration after braking, and a desired value is obtained from the motor 4f. May not be able to obtain the driving force. In such a case, the vehicle 100 cannot perform efficient acceleration at the time of re-acceleration after braking.

  The controller 7 according to the present embodiment considers the torque that can be output by the motor 4f, and the friction brake braking force and the regenerative braking force so that there is no difference in the temperature of the motor 4 provided on the left and right wheels 3f. Deriving the distribution. In the example shown in FIG. 2, broken arrows (A1R and A1L) indicate the regenerative braking force, and solid arrows (A2R and A2L) indicate the friction brake braking force. As shown in FIG. 2, the controller 7 according to the present embodiment changes the distribution of the friction brake braking force and the regenerative braking force applied to the wheels between the left and right wheels 3f in accordance with the vehicle state of the vehicle 100, thereby changing the left and right wheels 3f. The motor 4f is controlled so as not to cause a temperature difference (note that the length of the arrow is not accurate). Thereby, since the same maximum output can be obtained from the motor 4f of the left and right wheels 3f at the time of reacceleration after braking, the vehicle 100 can efficiently reaccelerate. A specific method for deriving the braking force distribution by the controller 7 will be described later.

  FIG. 3 is a block diagram showing the configuration of the controller 7 according to this embodiment. The controller 7 includes a required braking force calculation unit 71, a vehicle state acquisition unit 72, a distribution derivation unit 75, and a controller unit 76. The distribution deriving unit 75 includes a map creating unit 73 and a distribution determining unit 74.

  The required braking force calculation unit 71 calculates the required braking force independently for each of the left and right wheels 3f according to the amount of operation of the brake pedal 11 by the driver, the traveling state of the vehicle 100, and the like. That is, the required braking force calculation unit 71 calculates a required braking force constituted by the friction brake braking force and the regenerative braking force. In this case, the required braking force calculation unit 71 acquires the operation amount or the depression speed of the brake pedal 11 from the brake pedal operation amount sensor 13 as a signal S32, and acquires the angular speeds of the left and right wheels from the angular speed sensor 10 as a signal S1. In addition to this, the required braking force calculation unit 71 obtains various parameters corresponding to the traveling state of the vehicle 100 and calculates the required braking force. The signal S11 corresponding to the required braking force calculated as described above is supplied to the distribution determining unit 74.

  The vehicle state acquisition unit 72 receives the signal S1 supplied from the angular velocity sensor 10 described above, the signal S2 supplied from the battery 5, and the maximum output of the motor 4 stored in a memory (not shown) (hereinafter referred to as “maximum output”). Represents power) and a signal S9 supplied from the temperature sensor 12 is acquired. The maximum output of the motor 4 is an eigenvalue of the motor 4 and is the same value for the same motor. The vehicle state acquisition unit 72 supplies these acquired values to the map creation unit 73 as a signal S12.

  The distribution derivation unit 75 includes the map creation unit 73 and the distribution determination unit 74 as described above. Here, the processing of the distribution deriving unit 75 will be briefly described. The map creation unit 73 creates a map based on the vehicle state supplied from the vehicle state acquisition unit 72 and supplies this map to the distribution determination unit 74. This map shows the torque that can be output by the motor 4 defined based on the angular velocity of the left and right wheels 3f, the capacity of the battery 5, and the maximum output of the motor 4.

  The distribution determination unit 74 determines distribution using the map supplied from the map creation unit 73 based on the required braking force supplied from the required braking force calculation unit 71. In this case, the distribution determination unit 74 determines the distribution so that the temperature of the motor 4 of the left and right wheels 3f does not exceed a predetermined value. Specifically, if the temperature of the motor 4 is equal to or higher than a predetermined value, the distribution determination unit 74 derives the distribution so that the regenerative braking force by the motor 4 is reduced. In this case, the distribution determination unit 74 determines the distribution so that the decrease in the regenerative braking force by the motor 4 is compensated by the friction brake braking force by the friction brake 9. The distribution thus determined is supplied to the controller unit 76 as a signal S14.

  In addition, the distribution determination part 74 is not limited to what calculates | requires distribution itself of regenerative braking force and friction brake braking force. Instead of obtaining the distribution, a distribution ratio between the regenerative braking force to be applied and the friction brake braking force may be obtained, and an actual braking force value may be determined according to the distribution ratio.

  The controller unit 76 converts the acquired distribution, ie, the regenerative braking force and the friction brake braking force, into signals that can be handled by individual components so that the vehicle 100 can actually output the signals. Supply to the component. Specifically, the controller unit 76 supplies a control signal S5 corresponding to the friction brake braking force to the brake system 8. Further, the controller unit 76 supplies a signal S4 corresponding to the regenerative braking force to the inverter 6. When the vehicle 100 has a drive source other than the friction brake 9 and the motor 4 (hereinafter referred to as “other drive source 15”), the controller unit 76 also supports the braking force of the other drive sources 15. The signal 15 is supplied.

  The brake system 8 supplies the friction brake 9 with a hydraulic pressure (indicated by S8) based on the acquired control signal S5 and the brake pressure transmitted from the brake pedal 11 described above. Further, the inverter 6 acquires electric power corresponding to the acquired signal S4 from the battery 5, and supplies electric power S7 obtained by converting the acquired electric power to the motor 4.

  As described above, the friction brake 9 applies the requested friction brake braking force to the vehicle 100, and the motor 4 applies the requested regenerative braking force to the vehicle 100. Since the friction brake braking force and the regenerative braking force are distributed so that the temperature of the left and right motors 4 does not exceed a predetermined value as described above, the maximum output is obtained from each of the left and right wheel motors 4 during re-acceleration after braking. As a result, the vehicle 100 can perform efficient acceleration.

(Allocation derivation method)
Hereinafter, the distribution derivation method performed by the above-described distribution derivation unit 75 will be specifically described.

  FIG. 4 is a diagram illustrating an example of a map indicating torque that can be output by the motor 4. FIG. 4 shows only a map related to the motor 4f of the front wheel 3f for convenience of explanation, but basically the same map can be used for the rear wheel.

  In FIG. 4, the horizontal axis indicates torque applied to the right wheel 3 fR (hereinafter simply referred to as “right wheel torque”), and the vertical axis indicates torque applied to the left wheel 3 fL (hereinafter simply referred to as “left wheel torque”). Show. In FIG. 4, the right wheel torque and the left wheel torque both indicate the regenerative torque as “positive”.

  First, a map defined by the maximum output of the motor 4f and the capacity (charge amount) of the battery 5 will be described with reference to FIG. The map shown in FIG. 4A is created by the map creation unit 73 described above.

The right wheel torque output from the motor 4fR is “T _MR ”, and the left wheel torque output from the motor 4fL is “T _ML ”. The maximum output of the motor 4fR is “P _MR ”, and the maximum output of the motor 4fL is “P _ML ”. These maximum outputs P _MR and P _ML are eigenvalues of the motors 4fR and 4fL as described above. Usually, since the same motor is used for the left and right wheels, the maximum outputs P _MR and P _ML of the motors 4fR and 4fL have the same value. Further, the angular velocity of the right wheel 3fR is “ω _R ”, and the angular velocity of the left wheel 3fL is “ω _L ”. In this case, the torques T _MR and T _ML output from the motors 4fR and 4fL satisfy the conditional expressions (1) and (2) expressed using the maximum outputs P _MR and P _ML and the angular velocities ω _R and ω _L. ing.

T _MR ≦ P _MR / ω _R formula (1)
T _ML ≦ P _ML / ω _L formula (2)
From equations (1) and (2), it can be seen that the torques T _MR and T _ML output from the motor 4 decrease as the angular velocities ω _R and ω _L increase. From Equation (1), the maximum value of the torque T _MR output from the motor 4fR is “P _MR / ω _R ”, which can be represented by the straight line MR in FIG. That is, the torque output from the motor 4fR is located in the region on the left side of the straight line MR in FIG. Further, from Equation (2), the maximum value of the torque T _ML output from the motor 4 fL is “P _ML / ω _L ”, which can be represented by the straight line ML in FIG. That is, the torque output from the motor 4fL is located in the area below the straight line ML in FIG.

Further, the maximum outputs P _MR and P _ML described above satisfy the following conditional expression (3) when the capacity (charge amount) of the battery 5 is “P _SOC ”.

P _MR + P _ML ≦ P _SOC formula (3)
Equation (3) is motor 4FR, 4FL shows that it is impossible to issue capacity _{P SOC} or power of the battery 5. Here, if the above formulas (1) and (2) are substituted into the formula (3), the conditional formula (4) is obtained.

ω _R T _MR + ω _L T _ML ≦ P _SOC formula (4)
Expression (4) is represented by a straight line S in FIG. That is, in FIG. 4A, the torque output from the motor 4fR and the motor 4fL (hereinafter, the position on the map of FIG. 4 corresponding to this torque is called the “use point” of the motor 4f) is the straight line S. Located in the lower left area. When considering only the capacitance _{P SOC} of the battery 5 (i.e., above the motor 4FR, without considering the maximum output of 4FL), the maximum value of the right wheel torque _{T MR} output from the motor 4FR is _{"P SOC} / omega _R The maximum value of the left wheel torque T _ML output from the motor 4fL is “P _SOC / ω _L ”.

From the above conditional expressions (1) to (4), the torques T _MR and T _ML output from the motors 4fR and 4fL, that is, the use points of the motor 4f are limited to the range indicated by the region R1 in FIG. I understand that.

As described above, the map creation unit 73 outputs the motors 4fR and 4fL based on the angular velocities ω _R and ω _L , the capacity P _{SOC of the} battery 5, and the maximum outputs P _MR and P _{ML of} the motors 4fR and 4fL. Create a map for possible torques T _MR , T _ML .

  Next, a map defined based on the temperature of the motor 4 (hereinafter, this map is referred to as a “motor output restriction map”) will be described with reference to FIG. FIG. 4B shows a map (indicated by region R1) obtained by the above-described method in an overlapping manner. The motor output restriction map is created by the distribution determination unit 74 described above.

Here, a case where the temperature of only the motor 4fL of the left wheel 3fL is equal to or higher than a predetermined value will be described. Since the temperature of the motor 4fL is equal to or higher than the predetermined value, it is necessary to lower the motor temperature, it should not be used to maximize the torque T _ML defined from the region R1 for left wheel torque. Therefore, the distribution determining unit 74 changes a part defining the torque T _ML in the region R1 and sets a new region (that is, creates a new map).

More specifically, the linear MTL shown in FIG. 4 (b), to limit the torque _{T ML} output from the motor 4FL. That is, the allocation determination unit 74, a torque _{T ML} output from the motor 4fL is to be defined by a straight line MTL rather than a straight line ML. Specifically, motor 4fL is determined by linear MTL torque _{x (x <(P ML /} ω L)) and outputs the following values. In this case, the motor output restriction map corresponds to a region R2 (region indicated by diagonal lines) defined by the straight line S, the straight line MR, and the straight line MTL.

The straight line MTL is determined according to the temperature of the motor 4fL (for example, the difference between the temperature of the motor 4fL and a predetermined value). Therefore, when the temperature of the motor 4fL is high, “x” is smaller than “P _ML / ω _L ”. When the temperature of the motor 4fL is not extremely high, the difference between “x” and “P _ML / ω _L ” is small. However, “x” does not become a value larger than “P _ML / ω _L ”. That is, when the temperature of the motor 4fL is not high, the original region R1 is used.

  The motor output restriction map may be created by the map creation unit 73 instead of the distribution determination unit 74. In this case, the map creation unit 73 creates the motor output restriction map after creating the map shown in FIG.

  Next, a method for determining the use point of the motor 4f using the motor output restriction map described above will be described. This processing is also performed by the distribution determination unit 74. The distribution determination unit 74 determines the distribution of the friction brake braking force and the regenerative braking force that satisfy the required braking force using the generated motor output restriction map. In the following, a process in which the distribution determining unit 74 determines the amounts of the friction brake braking force and the regenerative braking force itself will be described.

  As in FIG. 4, FIG. 5 shows the right wheel torque on the horizontal axis and the left wheel torque on the vertical axis, and shows a map relating to the torque that can be output by the motors 4fR and 4fL. Also in this case, it is assumed that the vehicle 100 is turning leftward. For convenience of explanation, only the braking force applied to the front wheel 3f is shown.

  FIG. 5A shows a method for determining the use point of the motor 4f when the temperatures of the motors 4fR and 4fL are both lower than a predetermined value. In this case, the distribution determining unit 74 uses only the map shown in FIG. 4A without using the motor output restriction map shown in FIG. Specifically, a procedure for determining a use point of the motor 4f will be described with reference to FIG.

Now, it is assumed that the required braking force is at the position indicated by the point T1. Further, the coordinates of the point T1 are (α, β). That is, the required braking force to be applied to the right wheel 3fR is “α”, and the required braking force to be applied to the left wheel 3fL is “β”. In this case, the required braking force to be applied to the right wheel 3fR alpha is larger than the maximum value _{P MR} / omega _R the torque _{T MR,} and, the required braking force β to be given to the left wheel 3fL maximum value P of the torque _{T ML} larger than _ML / _{ω L.}

The use point of the motor 4f needs to be located in the region R1. For example, the distribution determining unit 74 determines the use point of the motor 4f as the point P1 in the region R1. Specifically, the torque to be output motor 4fR is determined as _{"T MR_rq"} torque motor 4fL to be output is determined as _{"T ML_rq".} In this case, the torque to be output by the friction brake 9fR is “T _{BR_rq} ”, and the torque to be output by the friction brake 9fL is “T _{BL_rq} ”. Therefore, the relationship between the torques T _MR , T _ML , T _BR , T _BL by the motors 4fR, 4fL and the friction brakes 9fR, 9fL is “α = T _{MR_rq} + T _{BR_rq} ” and “β = T _{ML_rq} + T _{BL_rq} ”.

  Next, a method for determining the use point of the motor 4f when the temperature of the motor 4fL is equal to or higher than a predetermined value will be described with reference to FIG. Here, a case where only the temperature of the motor 4fL is equal to or higher than a predetermined value is shown. In this case, the motor output restriction map corresponds to a region R2 defined by the straight line MTL shown in FIG. In FIG. 5B, the torque that can be output by the motor 4f is the same as the map (region R1) in FIG. 5A. Also, the required braking force is assumed to be the same.

In this case, the use point of the motor 4f for satisfying the required braking force needs to be located within the hatched region R2. For example, the distribution determination unit 74 determines the use point of the motor 4f as the point P2 in the region R2. The torque to be output by the motor 4fL is “T _{ML_Th} ”. The torque _{T ML_Th,} when the temperature of the motor 4fL compares the torque _{T ML_rq} required is lower than a predetermined _value, the _{T ML_Th <T ML_rq.} Therefore, compared with the case where the temperature of motor 4fL is lower than a predetermined value, the torque output from motor 4fL is reduced (indicated by arrow B1).

In addition, the torque indicated by the symbol y in FIG. 5B is the torque T _{ML_rq} required when the temperature of the motor 4fL is lower than a predetermined value, and the torque output when the temperature of the motor 4fL is equal to or higher than the predetermined value. It is a difference from _{TML_Th,} and “y = _{TML_rq} − _{TML_Th} ”.

Further, the torque by the friction brake 9fL is increased by the amount by which the torque by the motor 4fL is decreased (indicated by the arrow B2). That is, the torque to be output by the friction brake 9fL is “T _{BL_Th} ” (T _{BL_Th} > T _{BL_rq} ). In this case, the torque _{TBL_Th} is increased by “y” corresponding to the amount by which the torque output from the motor 4fL is decreased, and therefore satisfies “ _{TBL_Th} = _{TBL_rq} + ( _{TML_rq} − _{TML_Th} )”. .

Further, since the temperature of the motor 4fR is lower than the predetermined temperature, the torque by the motor 4fR remains “ _{TMR_rq} ”, and the torque by the friction brake is “ _{TML_rq} ”. That is, the distribution determination unit 74 does not decrease the torque due to the motor 4fR and does not increase the torque due to the friction brake.

  As described above, the distribution determining unit 74 decreases the torque output by the motor 4 and increases the torque by the friction brake 9 when the temperature of the motor 4 is equal to or higher than a predetermined value. Thereby, the temperature of the left and right motors 4 does not exceed a predetermined value. Therefore, no difference occurs in the driving force output from the left and right motors 4f during reacceleration after braking, so that the vehicle 100 can perform efficient reacceleration.

(Motor temperature suppression control)
Next, motor temperature suppression control will be described.

  FIG. 6 is a flowchart showing motor temperature suppression control performed by the controller 7 described above. This motor temperature suppression control refers to control in which the controller 7 determines a use point of the motor 4 so that the temperature of the motor 4 is not more than a predetermined temperature when the vehicle 100 is braked (during braking). Specifically, the controller 7 decreases the braking torque by the motor 4 in order to suppress the heat generation of the motor 4 having a temperature equal to or higher than a predetermined value. In this case, the controller 7 determines the use point of the motor 4 based on the map indicating the range of torque that can be output by the motor 4 and the temperature of the motor 4.

  The flowchart of FIG. 6 shows the case where the controller 7 performs the motor temperature suppression control only on the left wheel 3fL of the front wheel 3f. The motor temperature suppression control is repeatedly executed at a predetermined cycle. Furthermore, the motor temperature suppression control is performed by the distribution deriving unit 75 (the map creating unit 73 and the distribution determining unit 74) in the controller 7. In the following description, it is assumed that the processing is performed in the controller 7 without distinguishing the processing performed by the map creation unit 73 and the distribution determination unit 74.

  First, in step S101, the controller 7 determines whether or not the vehicle 100 is under brake control. In this case, the controller 7 determines whether or not the driver is operating the brake pedal 11 based on the signal S32 supplied from the brake pedal operation amount sensor 13. When the vehicle 100 is under brake control, since the regenerative braking force is used as the braking force, the temperature of the motor often increases. Therefore, it is determined whether or not it is necessary to limit the torque by determining whether or not the vehicle 100 is under brake control. If the vehicle 100 is under brake control (step S101; Yes), the process proceeds to step S102. If the vehicle 100 is not under brake control (step S101; No), the process proceeds to step S107.

In step S102, the controller 7 determines whether the detected temperature of the motor 4fL (hereinafter, this temperature is expressed as “Thm _L ”) is equal to or higher than a predetermined upper limit temperature (hereinafter, this temperature is expressed as “Thm _HI ”). Determine whether or not. Specifically, the controller 7 acquires the detected temperature Thm _L of the motor 4fL from the temperature sensor 12fL, and acquires the upper limit temperature Thm _HI stored in a memory (not shown). This upper limit temperature Thm _HI corresponds to an upper limit value of the motor temperature at which the maximum output can be obtained from the motor, and has a meaning as a start temperature of torque control described below. That is, if the temperature Thm _{L of the} motor 4fL is equal to or higher than the upper limit temperature Thm _HI , it is necessary to limit the torque in order to reduce the motor temperature. Therefore, when the temperature Thm _{L of the} motor 4fL is equal to or higher than the upper limit temperature Thm _HI (step S102; Yes), the process proceeds to step S103.

On the other hand, when the detected temperature Thm _L of the motor 4fL is lower than the upper limit temperature Thm _HI , there are cases where the torque limit is already being executed and where the torque limit is not being executed. In the former case, the temperature Thm _L of the motor 4fL is equal to or lower than the upper limit temperature Thm _HI due to execution of torque limitation. In the latter case, the vehicle 100 is under brake control, but the motor temperature is lower than the upper limit temperature Thm _HI , so that torque limitation is not executed. Therefore, when the detected temperature Thm _L is lower than the upper limit temperature Thm _HI , it is not necessary to newly limit the torque, but when it has been executed so far, the torque limitation is continued. Therefore, when the temperature Thm _L is lower than the upper limit temperature Thm _HI (step S102; No), the process proceeds to step S104.

In step S103, the controller 7 turns the torque limit flag (hereinafter also referred to as “xthmLlow”) “ON”. Here, since the detected temperature Thm _L of the motor 4fL is equal to or higher than the upper limit temperature Thm _HI , torque limitation is executed. Therefore, the controller 7 sets the torque limit flag indicating that torque limit is being executed to “ON”. Then, the process proceeds to step S106. Note that data relating to the torque limit flag (xthmLlow) is stored in a memory or the like in the controller 7.

In step S106, the controller 7 performs torque limitation using a motor output limitation map (hereinafter also referred to as “Thmlim_map”), and determines a use point of the motor 4f. This motor output restriction map corresponds to the map indicated by the region R2 in FIG. That is, the motor output restriction map is a map newly created in consideration of the detected temperature Thm _L of the motor 4fL in the map defined by the maximum output of the motor 4fL and the capacity of the battery 5. In this case, the controller 7 acquires the detected temperature Thm _L of the motor 4fL and creates a motor output restriction map. Based on the torque T _{ML_rq} required when the temperature Thm _{L of the} motor 4fL is lower than a predetermined value, motor 4fL determines the torque _{T ML} to be output. That is, since this torque T _ML is a function of the temperature Thm _L and the torque T _{ML_rq} , the processing performed by the controller 7 is indicated as “T _ML = Thmlim_map (Thm _L , T _{ML_rq} )”.

In this case, the torque T _BL friction brake 9fL to be output, it is necessary to increase an amount of reduced torque T _ML output from the motor 4fL by the torque limit. Since the amount in which the reducing is _"T ML_rq _{-T ML",} the torque _{T BL} friction brake 9fL to be output is _{"T BL = T BL_rq + (T} ML_rq -T ML) ". This torque _{TBL_rq} is a torque required for the friction brake 9fL when the temperature of the motor 4 is lower than a predetermined value.

When the above processing is completed, the flow is exited. After exiting the flow controller 7, a torque T _ML determined as described _above, the T _BL, performs control so as to output from the motor 4fL and friction brake 9FL.

Next, the case where the detected temperature Thm _L of the motor 4 is lower than the upper limit temperature Thm _HI (step S102; No) will be described. In step S104, the controller 7 determines whether or not the vehicle 100 is torque limited. Specifically, the controller 7 checks the torque limit flag (xthmLlow).

When the torque limit flag is “ON” (“xthmLlow == ON”), the detected temperature Thm _L of the motor 4 is lower than the upper limit temperature Thm _{HI due} to torque limit. In this case, when the detected temperature Thm _L of the motor 4 is still high and it is better to continue the torque limitation, and when the temperature Thm _{L of the} motor 4 is no longer high and the torque limitation may be terminated. There is. On the other hand, when the torque limit flag is “OFF”, the torque is not being limited, and the detected temperature Thm _L of the motor 4 is lower than the upper limit temperature Thm _HI . Therefore, it is not necessary to limit the torque. Therefore, when the torque limit flag is “ON” (step S104; Yes), the process proceeds to step S105. When the torque limit flag is “OFF” (step S104; No), the process proceeds to step S107.

In step S105, the controller 7 determines whether or not the temperature of the motor 4fL is equal to or higher than the lower limit temperature Thm _LO . The controller 7 acquires the detected temperature Thm _L of the motor 4fL from the temperature sensor 12fL. Then, the controller 7 acquires a lower limit temperature Thm _LO stored in a memory (not shown) or the like. This lower limit temperature Thm _Lo is set to a temperature that is low enough not to require torque limitation, and has a meaning as an end temperature of torque limitation. When the temperature Thm _{L of the} motor 4fL is equal to or higher than the lower limit temperature Thm _Lo , it is necessary to continue torque limitation. Therefore, in this case (step S105; Yes), the process proceeds to step S106 described above, and the controller 7 limits the output torque of the motor 4fL. Then, when the process of step S106 ends, the flow is exited.

On the other hand, if the temperature Thm _{L of the} motor 4fL is lower than the lower limit temperature Thm _Lo (step S105; No), the process proceeds to step S107.

  The process in step S107 is performed when it is determined in step S101, S104, or S105 that it is not necessary to limit the torque. Therefore, in step S107, the controller 7 sets the torque limit flag to “OFF” (“xthmLlow = OFF”). Then, the process proceeds to step S108.

In step S108, the controller 7 does not limit the torque and outputs a torque according to the required braking force. Specifically, the controller 7 is determined based on the torque T _BL outputted from the torque T _ML and friction brake 9fL output from the motor 4FL, the map defined by the capacity of the maximum output and the battery 5 of the motor 4f To do. For example, the controller 7 determines each torque using a map defined in the region R1 shown in FIG. That is, the controller 7 sets the torque _{T ML} output from the motor 4fL the requested torque _{T ML_rq,} set the friction brake 9fL torque requested torque _{T BL} outputted from the _{T BL_rq.} In this case, since torque limitation is not executed, the controller 7 does not decrease the torque by the motor 4fL and does not increase the torque by the friction brake.

When the above processing is completed, the flow is exited. After exiting the flow controller 7, a torque T _ML determined as described _above, the T _BL, performs control so as to output from the motor 4fL and friction brake 9FL.

  Thus, in the motor temperature suppression control described above, the motors are controlled so that the temperatures of the motors 4 of the left and right wheels 3 are all equal to or lower than the upper limit temperature. The temperature is maintained at which the output is obtained. Therefore, at the time of acceleration after the end of braking, both the left and right motors can be driven with the maximum output, and quick acceleration is possible. Also, by maintaining both motors below the upper limit temperature and eliminating temperature deviations between both motors, it is possible to obtain the same maximum output from both motors.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  First, the basic concept of the second embodiment will be briefly described. In general, it is known that when the capacity (charge amount) of a battery is in an overcharged state, the performance of the battery is reduced. Further, if the capacity of the battery 5 is frequently changed frequently, the battery life may be shortened. Therefore, in 2nd Embodiment, when the capacity | capacitance of the battery 5 exists in an overcharge state, it controls so that the motor 4 generate | occur | produces driving force instead of regenerative braking force, ie, the motor 4 carries out powering. In other words, the battery 5 is consumed to prevent the battery 5 from being overcharged.

  The brake control when the capacity of the battery 5 is in the overcharge state will be described with reference to FIG. 7 as a specific example. FIG. 7 shows a schematic view when a braking force is applied to the vehicle 100 at the time of turning (the direction indicated by the arrow A3). For convenience of explanation, only the braking force applied to the left and right wheels 3f of the front wheels will be described.

  Since the battery 5 of the vehicle 100 is in an overcharged state, the motor 4f applies a driving force without applying a braking force to the vehicle 100 for the reasons described above. In FIG. 7, arrows A4R and A4L indicate the driving force by the power running of the motor 4f, and arrows A5R and A5L indicate the friction brake braking force by the friction brake 9f (the length of the arrow is not accurate). In this case, the driving force by the power running of the motor 4f and the friction brake braking force by the friction brake 9f are made to satisfy the required braking force. That is, the driving force and the friction brake braking force by powering are set so that the difference between the friction brake braking force and the driving force matches the required braking force.

  As described above, in the present embodiment, since the motor 4f is powered when the battery 5 is in the overcharged state, it is possible to escape from the overcharged state. Therefore, the performance degradation of the battery 5 can be prevented. In addition, since the motor 4 is powered during braking, when the vehicle 100 re-accelerates after braking, a desired driving force by the motor 4 can be immediately applied to the vehicle 100. Therefore, the vehicle 100 can accelerate quickly in response to the re-acceleration request.

  The control according to the second embodiment is also applied to the vehicle 100 having the configuration shown in FIG. Further, the controller 7 having the configuration shown in FIG. 3 also derives the distribution between the driving force of the motor 4 and the braking force by the friction brake 9. That is, since the configuration of the vehicle 100 and the controller 7 according to the second embodiment is the same as that shown in the first embodiment, the description thereof is omitted.

(Allocation derivation method)
Next, a method for deriving the distribution between the driving force of the motor 4 and the braking force of the friction brake 9 when the battery 5 is in an overcharged state will be described. The controller 7 described above derives the distribution of the battery 5 in the overcharged state. Specifically, the map creation unit 73 and the distribution determination unit 74 in the controller 7 perform processing. In the following description, it is assumed that the processing is performed in the controller 7 without distinguishing the processing performed by the map creation unit 73 and the distribution determination unit 74.

  FIG. 8 is a diagram for explaining a method of determining a use point of the motor 4 when the battery 5 is in an overcharged state. FIG. 8 shows the right wheel torque on the horizontal axis and the left wheel torque on the vertical axis, with the regenerative torque in the positive direction and the power running torque in the negative direction. Here, for convenience of explanation, only the torque related to the front wheel 3f is shown. Further, it is assumed that the vehicle 100 is turning in the left direction. In the following, a case will be described in which the distribution determination unit 74 does not derive the distribution ratio but determines the distribution by deriving the driving force (torque) by the motor 4 itself.

  The required braking force is assumed to be at the position indicated by the point T1. Further, the coordinates of the point T1 are assumed to be “(α, β)”. That is, the required braking force to be applied to the right wheel 3fR is α, and the required braking force to be applied to the left wheel 3fL is β. As described above, the torque that can be output by the motor 4f is determined based on the angular velocity of the motor 4f, the capacity of the battery 5, and the maximum output of the motor 4f, and is represented by a region R1 in FIG.

  Here, since the battery 5 is in an overcharged state, the controller 7 causes the motor 4f to regenerate without regenerating as described above. Therefore, the motor 4f of the left and right wheels 3 does not output the torque in the region R1, but outputs the torque in the region R3. This region R3 is obtained by moving the region R1 to a negative region with point symmetry about the origin. In FIG. 8, a positive value torque indicates a braking force and a negative value torque indicates a driving force. Therefore, when the motor 4f outputs a torque in the region R3, the driving force is applied to the vehicle 100. Is done. Further, since the absolute value of the torque that can be output by the motor 4f is determined by the maximum output of the motor 4f, the power of the battery 5, and the like, the torque applied to the vehicle does not change regardless of whether it is braking force or driving force. And the region R3 has a point-symmetric shape about the origin.

From the region R3 determined as described above, the use point of the motor 4f is determined. For example, the controller 7 determines the use point of the motor 4f as the point P3 in the region R3. Specifically, the torque to be output by the motor 4fL is “ _{TML_Ba} ”, and the torque to be output by the motor 4fR is “ _{TMR_Ba} ”. These torques T _{ML_Ba} and T _{MR_Ba} are negative values.

As described above, when the torque by the motor 4f takes a negative value, it is necessary to set the torque output by the friction brake 9f in consideration of these torques. That is, since the motor 4f outputs driving force, the friction brake 9f needs to output extra braking torque by the amount of driving force generated by the motor 4f to cancel the power running torque by the motor 4. Specifically, the friction brake 9fL may output an extra torque (torque indicated by z2) corresponding to the torque _{TML_Ba} output by the motor 4fL. Similarly, the friction brake 9fR may output an extra torque (torque indicated by reference sign z1) corresponding to the torque _{TMR_Ba} output by the motor 4fR. That is, the torque T _{BL_Ba} output from the friction brake 9fL is
_{TBL_Ba} = β + z2 = β + | _{TML_Ba} |
The torque T _{BR_Ba} output from the friction brake 9fR is
T _BR — _Ba = α + z1 = α + | T _{MR_Ba} |
It becomes. As a result, the resultant force of the braking force by the friction brake 9f and the driving force of the motor 4f matches the required braking force required for the vehicle 100.

  Thus, when the battery 5 is in an overcharged state, the controller 7 causes the motor 4 to power and consumes power. Thereby, an overcharge state can be avoided and the performance fall of the battery 5 can be prevented. In addition, since the motor 4 is powered during braking, when the vehicle 100 re-accelerates after braking, the driving force from the motor 4 is immediately applied to the vehicle 100. Therefore, the vehicle 100 can perform quick acceleration at the time of reacceleration.

  In general, when the frictional state (μ) of the road surface suddenly changes during braking, it is desirable to respond by instantly increasing the braking force accordingly. However, if the change in the braking force is to be dealt with by the friction brake braking force, the response time cannot be made sufficiently fast because it takes time to transmit the hydraulic pressure. In this regard, according to the control of the present embodiment, since the motor 4 is in a power running state, immediately after the road friction state changes, the motor is controlled to switch from power running to regeneration so that the braking force can be changed with good responsiveness. There is an advantage that it can cope.

(Brake control processing)
FIG. 9 is a flowchart showing a brake control process performed by the controller 7 described above. In this brake control process, the controller 7 determines the use point of the motor 4 and controls the friction brake braking force determined by the use point of the motor 4 to be output from the friction brake 9 and the driving force from the motor 4. Say. The brake control process in FIG. 9 particularly shows a process related to the determination of the use point of the motor 4 when the battery 5 is overcharged.

  The brake control process shown in FIG. 9 starts when the driver operates the brake pedal 11. Specifically, the controller 7 starts the brake control process when the signal S32 from the brake pedal operation amount sensor 13 is acquired.

  First, in step S <b> 201, the controller 7 calculates a required braking force to be applied to each of the front, rear, left and right wheels 3 according to the amount of operation of the brake pedal 11 by the driver, the traveling state of the vehicle 100, and the like. Specifically, the controller 7 acquires the operation amount of the brake pedal 11 (may be the depression speed of the brake pedal 11) as the signal S32 from the brake pedal operation amount sensor 13, and acquires the angular velocity as the signal S1 from the angular velocity sensor 10. . The above processing is performed by the required braking force calculation unit 71 in the controller 7, and the signal S <b> 11 corresponding to the calculated required braking force is supplied to the distribution determination unit 74 in the controller 7. Then, the process proceeds to step S202.

  In step S <b> 202, the controller 7 acquires the angular velocity of the front, rear, left and right wheels 3, the capacity of the battery 5, and the maximum output of the motor 4. Specifically, the controller 7 acquires the signal S1 supplied from the angular velocity sensor 10, the signal S2 supplied from the battery 5, and the maximum output (power) of the motor 4 stored in a memory or the like as the vehicle state. To do. The above processing is performed by the vehicle state acquisition unit 72 in the controller 7, and these acquired values are supplied to the map creation unit 73 in the controller 7. Then, the process proceeds to step S203.

  In step S203, the controller 7 creates a map using the vehicle state acquired in step S202. Specifically, the controller 7 creates a map relating to torque that can be output by the motor 4 based on the angular velocity, the capacity of the battery 5, and the maximum output of the motor 4. This processing is performed by the map creation unit 73 in the controller 7, and the created map is supplied to the distribution determination unit 74 in the controller 7. Then, the process proceeds to step S204.

  In step S204, the controller 7 determines the use point of the motor 4 based on the required braking force acquired in step S201 and the map acquired in step S203. In this case, since the battery 5 is in an overcharged state, the controller 7 determines a use point of the motor 4 so that the motor 4 is powered. At this time, the controller 7 refers to the acquired map, and determines a use point from the range of torque that the motor 4 can output, as described with reference to FIG. The above processing is performed by the distribution determining unit 74 in the controller 7. Then, the process proceeds to step S205.

  In step S205, the controller 7 determines the driving force of the motor 4 from the use point of the motor 4 determined in step S204. Then, the process proceeds to step S206. In step S206, the controller 7 determines the friction brake braking force of the friction brake 9 based on the use point of the motor 4 determined in step S204 and the required braking force acquired in step S201. In this case, the controller 7 determines that the friction brake braking force of the friction brake 9 matches the sum of the driving force by the motor 4 and the required braking force determined in step S204. Then, the process proceeds to step S207. Note that the processing of steps S205 and S206 is also performed by the distribution determination unit 74 in the controller 7.

  In step S207, the controller 7 causes the motor 4 to output the determined driving force and causes the friction brake 9 to output the determined brake braking force. Specifically, the controller unit 76 in the controller 7 supplies the brake system 8 with a control signal S5 corresponding to the friction brake braking force, and supplies the inverter 6 with a control signal S4 corresponding to the driving force of the motor 4. To do. The brake system 8 supplies the friction brake 9 with hydraulic pressure based on the acquired control signal S5 and the brake pressure transmitted from the brake pedal 11. Further, the inverter 6 supplies electric power S7 corresponding to the acquired signal S4 to the motor 4. As described above, the friction brake 9 applies the required friction brake braking force to the vehicle 100, and the motor 4 applies the required driving force to the vehicle 100.

  As described above, in the second embodiment, when the battery 5 is in the overcharged state, the motor 4 is powered to avoid the overcharged state of the battery 5. Therefore, the performance degradation of the battery 5 can be prevented. In addition, since the motor 4 is powered during braking, acceleration can be started quickly when the vehicle 100 re-accelerates after braking.

  When the above processing is completed, if the driver is operating the brake pedal 11, the controller 7 returns to step S201 and performs the same processing again. If the driver has finished operating the brake pedal 11, the controller 7 finishes the brake control process.

[Modification]
Although control by said 1st Embodiment and 2nd Embodiment cannot be made compatible simultaneously, it can switch to time and can apply to one vehicle, for example. That is, as described above, since the necessary configuration is substantially the same, the control of the first embodiment that suppresses the temperature rise of the motor according to the traveling state of the vehicle and the second to prevent the battery from being overcharged. It is possible to apply the control of the embodiment by switching over time on the same vehicle.

1 is a block diagram showing a schematic configuration of a vehicle according to an embodiment of the present invention. It is a figure which shows the basic concept of 1st Embodiment of this invention. It is a block diagram which shows schematic structure of the controller which concerns on embodiment of this invention. It is a figure which shows the map showing the torque which a motor can output. It is a figure for demonstrating the determination method of the use point of the motor which concerns on 1st Embodiment. It is a flowchart which shows the motor temperature suppression control which concerns on 1st Embodiment. It is a figure which shows the basic concept of 2nd Embodiment of this invention. It is a figure for demonstrating the determination method of the use point of the motor which concerns on 2nd Embodiment. It is a flowchart which shows the brake control process which concerns on 2nd Embodiment.

Explanation of symbols

1 engine 3 wheels (front / rear left / right wheels)
4 Motor 5 Battery 6 Inverter 7 Controller 8 Brake system 9 Friction brake 11 Brake pedal 100 Vehicle

Claims (1)

A brake control device mounted on a vehicle,
A motor for independently driving and regenerating left and right wheels of the vehicle;
A friction brake provided on each of the left and right wheels;
Vehicle state acquisition means for acquiring the vehicle state of the vehicle;
Distribution derivation means for deriving distribution of the braking force or driving force of the motor and the braking force of the friction brake to each of the left and right wheels based on the acquired vehicle state;
Control means for outputting a braking force or a driving force corresponding to the derived distribution from the motor and the friction brake;
The vehicle state acquisition means acquires a charge amount of a battery that supplies electric power to the motor,
The distribution deriving means derives the distribution so that the motor is powered when the charge amount of the battery exceeds a predetermined value, and outputs a driving force output when the motor is powered. The brake control device , wherein the distribution is determined so as to cancel out by a braking force .

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