JP6838478B2 - Driving force control device - Google Patents

Description

The present invention relates to a device for controlling a driving force of a vehicle in which a motor is connected to each of a plurality of driving wheels.

Patent Document 1 and Patent Document 2 describe a vehicle driving force control device in which a motor is connected to each of a plurality of driving wheels. The driving force control device described in Patent Document 1 is configured to perform power running control of motors connected to each of a pair of front wheels and regenerative control of motors connected to each of a pair of rear wheels. .. Further, each motor is controlled so that the total value of the driving force generated by the front wheels and the driving force (braking force) generated by the rear wheels is the driving force required for the vehicle.

The vehicle described in Patent Document 2 has motors connected to the left drive wheel and the right drive wheel, respectively, and includes a friction clutch that enables torque transmission between the motors. The torque transmission capacity of the friction clutch is controlled according to the road conditions. In addition, the driving force control device that controls each motor determines whether to run by outputting power from only one motor or by outputting power from two motors, depending on the road conditions and vehicle speed. , It defines whether to control the power running or regenerative control of each motor. Specifically, it is configured to output power from only one motor when traveling in suburban road conditions and at low vehicle speeds, and to output power from two motors when traveling in suburban road conditions and at medium and high vehicle speeds. Has been done.

Japanese Unexamined Patent Publication No. 2011-188557 Japanese Unexamined Patent Publication No. 2016-59269

When the driving force is output from one of the front wheels and the rear wheels and the braking force is output from the other as in the vehicle driving force control device described in Patent Document 1, either the front wheels or the rear wheels are output. Since the amount of slip between the drive wheels and the road surface increases, the durability of the drive wheels may decrease. Further, when the slip amount becomes large as such, the power loss between the drive wheels and the road surface becomes large, so that even if the motor can be operated at an efficient operating point, the vehicle's output with respect to the motor output can be increased. Acceleration may be small. That is, the power loss of the vehicle as a whole may increase.

In addition, a motor provided as a driving force source for a vehicle generally becomes more efficient as the torque increases up to a predetermined torque. Therefore, when traveling at a low vehicle speed as in the vehicle driving force control device described in Patent Document 2, if the vehicle travels with the power of one motor, the torque output from that motor increases. The motor can be operated at a more efficient operating point as compared with the case where the motor is driven by the power of one motor. On the other hand, when the motor configured as described above outputs a torque equal to or higher than a predetermined torque, the efficiency deteriorates as the torque increases. Therefore, when the driving force required for the vehicle is large, the motor has a large efficiency. Running with one motor may result in lower efficiency than running with two motors. In addition, even when a torque smaller than a predetermined torque is output, it is more efficient to operate the two motors by power running control of one motor and regenerative control of the other motor. There is a possibility of becoming. Therefore, if the motor to be operated according to the road condition is uniformly defined and the transmission torque capacity of the clutch is uniformly defined as in the driving force control device described in Patent Document 2, the efficiency of the vehicle as a whole is good. You may not be able to drive.

The present invention was conceived by paying attention to the above technical problems, and by appropriately controlling a plurality of motors provided for each of the drive wheels, the efficiency of the vehicle as a whole during traveling can be improved. It is an object of the present invention to provide a driving force control device which can be performed well.

In order to achieve the above object, the present invention comprises a first motor connected to a drive wheel on the right side of the vehicle, a second motor connected to a drive wheel on the left side of the vehicle, the first motor and the above. A drive device having a clutch capable of transmitting torque to and from the second motor and having a changeable transmission torque capacity, and a power source for supplying power to the first motor and the second motor. in the driving force control apparatus provided with, wherein the first motor the second motor and the output torque, and a controller for controlling the transmission torque capacity of the clutch, the controller, the total required for the drive unit A plurality of combinations of the provisional torque of the first motor and the provisional torque of the second motor, wherein the torque is obtained and the total value of the output torque of the first motor and the output torque of the second motor is the total torque. Of the plurality of obtained combinations, the combination of the provisional torque of the first motor that minimizes the output power amount of the power supply and the provisional torque of the second motor is selected and selected. and with a combination on the basis of the temporary torque of the first motor to output the torque from the first motor, output said torque from the second motor on the basis of the temporary torque of the second motor combination said selected , The first required torque required for the right drive wheel and the second required torque required for the left drive wheel are obtained, respectively, and when the first required torque and the second required torque are different from each other. Is the torque required for the first drive wheel having a larger required torque among the right drive wheel and the left drive wheel, and the first of the first motor and the second motor. The transmission torque capacity of the clutch is obtained by subtracting from the provisional torque of the selected combination of one of the first control motors connected to the drive wheels, and the transmission torque capacity of the clutch is obtained based on the obtained transmission torque capacity. that it has been configured to control the is characterized in.

According to the present invention, the first motor connected to the right drive wheel and the second motor connected to the left drive wheel can transmit torque via the clutch. Further, a plurality of combinations of the provisional torque of the first motor and the second provisional torque, in which the total value of the output torques of the respective motors is the total torque required for the drive device, are obtained, and among the obtained plurality of combinations. The combination that minimizes the output power amount of the power supply is selected, and the torque is output from each motor based on the provisional torque of the selected combination. That is, the output torque of each motor is controlled based on the torque required for the drive device. Therefore, it is possible to suppress the output of excessive torque from the drive device, and it is possible to suppress an increase in the slip amount of any of the drive wheels. As a result, it is possible to suppress a decrease in the durability of each drive wheel, and it is possible to suppress an increase in power loss generated between the drive wheel and the road surface. In other words, the efficiency of the vehicle as a whole can be improved.

It is sectional drawing for demonstrating an example of the 1st drive device provided with the motor connected to each pair of front wheels, and the clutch which enables the transmission of torque between motors. It is a schematic diagram for demonstrating an example of the vehicle which can be the object of this invention. It is a block diagram for demonstrating the structure of 1st ECU. It is a block diagram for demonstrating the structure of 2nd ECU. It is a schematic diagram for demonstrating the relationship of the operating point of each motor which can satisfy the required torque of a 1st drive device. It is a figure for demonstrating an example of the map for straight running. It is a figure for demonstrating an example of the map for turning travel. It is a flowchart for demonstrating an example of control of a driving force control device in embodiment of this invention.

In a vehicle that can be targeted by the present invention, drive motors (hereinafter, simply referred to as motors) are connected to at least one pair of drive wheels, that is, front wheels and rear wheels, and the motors are connected to each other. It is equipped with a clutch that enables the transmission of torque. An example of a drive device including these motors and a clutch is schematically shown in FIG. The drive device 1 shown in FIG. 1 is configured to have substantially symmetrical shapes on both sides of the central portion in the vehicle width direction. Therefore, in the following description, the configuration of one side (right side in the figure) will be described, the configuration of the other side will be described only for the portion having a configuration different from that of the one side, and the description of the configuration of the other portion will be omitted. .. For configurations in which one side and the other side are the same, "R" is added to the reference code of the member on one side in the drawing, "L" is added to the reference code of the member on the other side, and the following When it is necessary to distinguish between the member on one side and the member on the other side in the explanation, "first" is added to the name of the member on one side and "first" is added to the name of the member on the other side. 2 ”is added.

The drive device 1 includes a motor 2 as a drive force source. The motor 2 is a motor having a power generation function similar to a motor provided as a driving force source for a conventionally known hybrid vehicle or electric vehicle, and is composed of a permanent magnet type synchronous motor as an example. There is.

The output shaft 3 of the motor 2 extends in the vehicle width direction, and the output gear 4 is connected to a portion extending toward the center in the vehicle width direction. Further, a counter shaft 5 is provided in parallel with the output shaft 3, a counter driven gear 6 having a diameter larger than that of the output gear 4 is connected to one end of the counter shaft 5, and a counter is connected to the other end. A pinion gear 7 having a diameter smaller than that of the driven gear 6 is connected. Further, the pinion gear 7 is connected to a final reduction gear 8 having a diameter larger than that of the pinion gear 7.

A cylindrical shaft 9 that protrudes outward in the vehicle width direction and has an open end thereof is connected to the center of rotation of the final reduction gear 8. Then, one end of the drive shaft 10 is spline-engaged with the cylindrical shaft 9, and the drive wheel 11 is connected to the other end of the drive shaft 10. In the following description, for convenience, the gear ratio of the torque transmission path from the motor 2 to the drive wheels 11 is set to "1".

A disk-shaped brake rotor 12 is connected to the end of the output shaft 3 that extends outward in the vehicle width direction. The brake rotor 12 is made of a magnetic material. An annular brake stator 13 is provided facing the brake rotor 12. The brake stator 13 is spline-engaged with the case C so that it can approach the brake rotor 12 and cannot rotate. Further, the brake stator 13 is provided with a coil 14, and is configured so that the brake stator 13 and the brake rotor 12 come into contact with each other by an electromagnetic force generated by energizing the coil 14.

When the brake stator 13 and the brake rotor 12 come into contact with each other in this way, braking torque acts on the brake rotor 12 according to the frictional force. That is, the brake stator 13, the brake rotor 12, and the coil 14 constitute the friction brake 15.

Further, a hat-shaped extension shaft 16 is connected to the tip on the center side in the vehicle width direction of the first output shaft 3R to which the first output gear 4R is connected, and an annular clutch is connected to the extension shaft 16. The disks 17 are integrally rotatably connected.

Further, the tip of the second output shaft 3L on the center side in the vehicle width direction from the position where the second output gear 4L is connected is formed in a bottomed cylindrical shape, and the clutch disk 17 is housed in the hollow portion. The cover shaft 18 is connected.

An annular pressure plate 19 is provided between the bottom surface of the cover shaft 18 and the clutch disc 17. The pressure plate 19 is made of a magnetic material, and is spline-engaged with the cover shaft 18 so that the pressure plate 19 can rotate integrally with the cover shaft 18 and move in the direction of the rotation axis of the cover shaft 18. There is.

Further, a spring 20 for pressing the pressure plate 19 toward the clutch disc 17 is provided between the bottom surface of the cover shaft 18 and the pressure plate 19.

Further, a coil 21 is provided on the outside of the cover shaft 18, and the coil 21 resists the direction in which the pressure plate 19 is separated from the clutch disc 17 by energization, that is, the spring force of the spring 20. It is configured to generate electromagnetic force in the direction.

The clutch disc 17, the pressure plate 19, the spring 20, and the coil 21 constitute an electromagnetic clutch (hereinafter, simply referred to as a clutch) 22. When the coil 21 is not energized, the spring force of the spring 20 is formed. When the clutch disc 17 and the pressure plate 19 come into contact with each other and rotate integrally, and the coil 21 is energized, the transmission torque capacity between the clutch disc 17 and the pressure plate 19 is set according to the electric power.

Therefore, by frictionally engaging the pressure plate 19 and the clutch disc 17 without energizing the coil 21, the first motor 2R and the second motor 2L can be integrally rotated, or the first motor 2R and the first motor 2R and the first motor 2R can be rotated integrally. Torque can be transmitted to and from the two motors 2L. Further, by energizing the coil 21, the transmission torque capacity between the pressure plate 19 and the clutch disc 17 can be reduced, the first motor 2R and the second motor 2L are relatively rotated, and the first motor 2R and the first motor 2R are rotated. The torque transmitted by the second motor 2L can be reduced.

Further, the drive device 1 shown in FIG. 1 further includes a parking lock mechanism 23 capable of applying braking torque to the drive wheels 11R and 11L when the power of the vehicle is turned off. The parking lock mechanism 23 is configured to maintain the contact pressure between the first brake rotor 12R and the first brake stator 13R even when the power of the vehicle is turned off. Specifically, the parking lock mechanism 23 operates an annular movable plate 24, a feed screw mechanism 25, and a feed screw mechanism 25 provided on the side opposite to the first brake rotor 12R with the brake stator 13R interposed therebetween. It includes a braking motor 26.

The feed screw mechanism 25 is an actuating device that converts the rotary motion due to the torque output by the braking motor 26 into a linear motion and presses the movable plate 24 toward the first brake stator 13R. The parking lock mechanism 23 applies a torque in a predetermined rotation direction (forward rotation direction) to the feed screw mechanism 25 by the braking motor 26, thereby moving the movable plate 24 and the first brake stator 13R into the first brake rotor 12R. By pressing it sideways, the first brake rotor 12R and the first brake stator 13R are frictionally engaged with each other to brake the first output shaft 3R. By applying torque in the reverse direction to the feed screw mechanism 25 by the braking motor 26, the braking of the first output shaft 3R by the parking lock mechanism 23 can be released.

Further, in the feed screw mechanism 25 of the parking lock mechanism 23, the reverse efficiency of the feed screw when converting the linear motion into the rotary motion is set lower than the positive efficiency of the lead screw when converting the rotary motion into the linear motion. ing. Therefore, the feed screw mechanism 25 can press the movable plate 24 and the first brake stator 13R toward the first brake rotor 12R to maintain the state in which the first output shaft 3R is braked. Therefore, even if the above-mentioned first coil 14R and the braking motor 26 are stopped from being energized while the feed screw mechanism 25 is operated by the braking motor 26 and the first output shaft 3R is braked, parking is performed. The braking state of the first output shaft 3R by the lock mechanism 23 can be maintained. Therefore, the feed screw mechanism 25 converts the rotary motion into a linear motion to generate a thrust for braking the first output shaft 3R, and at the same time, generates a thrust to hold the state in which the first output shaft 3R is braked. It is a thrust generation mechanism that can be used.

In the drive device 1 described above, when the power supply is turned off, the supply of electric power to the coil 21 is stopped, so that the clutch 22 is in an engaged state. Therefore, by stopping the rotation of the first output shaft 3R by the parking lock mechanism 23, the rotation of the second output shaft 3L is also stopped. That is, it is possible to maintain a state in which the braking torque is applied to the drive wheels 11R and 11L. The parking lock mechanism 23 may be provided so as to prohibit the rotation of the second output shaft 3L, and is not limited to the first output shaft 3R, for example, prohibits the rotation of the first counter shaft 5R. It may be provided as follows.

When the drive device 1 described above completely engages the clutch 22 to rotate the left and right drive wheels 11R and 11L integrally, or transmits the same torque to the left and right drive wheels 11R and 11L to travel. Is to output torque from at least one of the motor 2R (2L) of the first motor 2R and the second motor 2L to travel, or to run with one motor 2R of the first motor 2R and the second motor 2L ( The drive torque is output from 2L), and the other motor 2L (2R) of the first motor 2R and the second motor 2L can regenerate a part of the drive torque to travel, or the first motor 2R. A large torque is output from one motor 2R (2L) of the 1 motor 2R and the second motor 2L, and a insufficient torque is output from the other motor 2L (2R). The torque to be applied can be set as appropriate.

Further, when the left and right drive wheels 11R and 11L are relatively rotated, such as when turning, or when the torque transmitted to the left and right drive wheels 11R and 11L is different, the clutch 22 is slipped and the motors 2R and 2L are moved. , The same as above, the torque is output from at least one of the motors 2R (2L) to run, or the drive torque is output from one motor 2R (2L) and the other motor 2L (2R) is the drive torque. It is possible to regenerate a part of the motors to travel, and the torque output from the respective motors 2R and 2L can be appropriately set.

Further, when the difference in rotation speed between the left and right drive wheels 11R and 11L is larger than a predetermined value, or when the torque difference transmitted to the left and right drive wheels 11R and 11L is larger than a predetermined value, the clutch 22 is completely released. , The outputs of the left and right drive wheels 11R and 11L can be appropriately determined. In that case, for example, the motor 2R (2L) connected to the outer ring may be driven to regenerate the motor 2L (2R) connected to the inner ring, and only the motor 2R (2L) connected to the outer ring may be regenerated. The torque may be output.

Next, a configuration example of the control system S of the vehicle Ve provided with the drive device 1 described above will be described. FIG. 2 is a schematic diagram for explaining an example of the system configuration. In the example shown in FIG. 2, the above-mentioned drive device 1 is provided at the center in the vehicle width direction and at the front and rear of the vehicle Ve, respectively. That is, the vehicle Ve shown in FIG. 2 is a four-wheel drive vehicle. The drive device (hereinafter referred to as the first drive device) 1 provided in front of the vehicle Ve and the drive device (hereinafter referred to as the second drive device) 1'provided behind the vehicle Ve are the vehicle. It is formed in a target shape with the central portion in the front-rear direction of Ve sandwiched between them. In the following description, a member (including the first motor 2R) provided in the torque transmission path between the first motor 2R and the right drive wheel 11R in the first drive device 1 of the second drive device 1'. The same configuration as () is provided with a "third" in its name and is provided in the torque transmission path between the second motor 2L and the left drive wheel 11L in the first drive device 1. The same configuration as the second motor 2L) is given a "fourth" in its name, and further, the clutch and parking lock mechanism provided in the second drive device 1', and the members constituting them. Add "second" to the name. Further, in order to distinguish between the member constituting the second drive device 1'and the member provided in the first drive device 1, "'" is added to the reference code.

The first motor 2R, the second motor 2L, and the coils 14R, 14L, and 21 described above are made of a battery, a capacitor, or the like, similar to a power storage device mounted on a conventionally known hybrid vehicle or electric vehicle. It is configured so that power is supplied from the voltage storage device 27. Similarly, electric power is supplied from the power storage device 27 to the motors 2R', 2L'and the coils 14R', 14L', 21' built in the second drive device 1'. Further, the power storage device 27 is configured to be supplied with the electric power generated by each of the motors 2R, 2L, 2R', 2L'. The power storage device 27 corresponds to the "power source" in the embodiment of the present invention.

A first inverter 28 capable of switching between a direct current and an alternating current between the power storage device 27 and the motors 2R and 2L and controlling the current value and its frequency supplied to the motors 2R and 2L. Is provided. Similarly, a second inverter 29 capable of controlling the current value supplied to the second drive device 1'and its frequency is provided.

Each motor 2R, 2L and each coil 14R, 14L, 21, provided in the first drive device 1 described above, each motor 2R', 2L'and each coil 14R', 14L' provided in the second drive device 1'. A first electronic control device (hereinafter, referred to as a first ECU) 30 for collectively controlling, 21'is provided. The first ECU 30 corresponds to the "controller" in the embodiment of the present invention, and is mainly composed of a microcomputer like a conventionally known electronic control device mounted on a vehicle. A block diagram for explaining the configuration of the first ECU 30 is shown in FIG.

Data related to the attitude of the vehicle Ve and signals such as the operating state of the operation unit by the driver are input to the first ECU 30, and the input signals are based on a calculation formula or a map stored in advance. Therefore, it is configured to output a control signal to the first inverter 28 and the second inverter 29. When obtaining the control signal output from the first ECU 30 to the first inverter 28 and the second inverter 29, conventionally known anti-lock system (ABS), traction control (TRC), electronic stability control (ESC), etc. It is obtained in consideration of dynamic yaw rate control (DYC) and the like.

As an example of the operation state signal input to the first ECU 30, the accelerator pedal sensor 31 for detecting the depression amount of the accelerator pedal, the first brake pedal sensor 32 for detecting the depression force of the brake pedal, and the depression amount of the brake pedal are used. It is a signal from the second brake pedal sensor 33 to detect, the steering angle sensor 34 to detect the steering angle of the steering wheel, and the torque sensor 35 to detect the steering torque of the steering wheel, and is an example of a signal of data related to the attitude of the vehicle Ve. Is a first G sensor 36 that detects the front-rear acceleration of the vehicle Ve, a second G sensor 37 that detects the lateral acceleration of the vehicle Ve, a yaw rate sensor 38 that detects the yaw rate of the vehicle Ve, a right front wheel 11R, a left front wheel 11L, and a right rear wheel. These are signals from the wheel speed sensors 40, 41, 42, and 43 that detect the peripheral speeds of the 39R and the left rear wheel 39L, respectively.

The first auxiliary battery 44 is provided in order to operate the first ECU 30 and to supply electric power for controlling a transistor (not shown) mounted on the first inverter 28. The first auxiliary battery 44 has a lower voltage than the power storage device 27.

As described above, when the parking lock mechanism 23 fails in the electric system between the first ECU 30 and the first auxiliary battery 44, such as when power cannot be supplied to the coils 14R, 14L, 21. Alternatively, it is preferable that the control can be performed even when a failure occurs in the electric system between the power storage device 27 and the first inverter 28. Therefore, in the example shown in FIG. 2, another electronic control device (hereinafter referred to as the second ECU) 45 is provided in addition to the first ECU 30. The second ECU 45 is also electrically connected to the parking lock mechanisms 23, 23'(specifically, the braking motors 26, 26'). Like the first ECU 30, the second ECU 45 is mainly composed of a microcomputer. A block diagram for explaining the configuration of the second ECU 45 is shown in FIG.

Data related to the attitude of the vehicle Ve and signals such as the operating state of the operation unit by the driver are input to the second ECU 45, and based on the input signals and a calculation formula or map stored in advance. It is determined whether or not to permit the operation of each parking lock mechanism 23, 23', and the control amount of each parking lock mechanism 23, 23'is determined by calculation or the like, and based on the determined control amount, the control amount is determined. It is configured to output a control signal to each of the parking lock mechanisms 23 and 23'.

As an example of the operation state signal input to the second ECU 45, the current values energized in the first brake pedal sensor 32, the second brake pedal sensor 33, and the friction brakes 15R, 15L, 15R', 15L' are used. It is a signal from a sensor (not shown) to be detected, and as an example of a signal of data related to the attitude of the vehicle Ve, it is a signal from the wheel speed sensors 40, 41, 42, 43. Further, the permission to operate the parking lock mechanisms 23, 23'is that the vehicle has been stopped for a predetermined time or longer, and the switch for operating the braking motors 26, 26'is turned on by the driver or the like. Judgment is made based on whether the vehicle is stopped, the ignition is turned off, or at least one of the friction brakes 15R, 15L, 15R', 15L'cannot be operated. can do.

Further, the braking torque by each parking lock mechanism 23, 23'is determined from the depressing force and depressing amount of the brake pedal and the wheel speeds of the drive wheels 11R, 11L, 39R, 39L, so that the braking torque can be obtained. It is configured to output current to each braking motor 26, 26'. A second auxiliary battery 46 is provided to operate the second ECU 45 and to supply electric power for controlling the parking lock mechanisms 23 and 23'. It should be noted that the signal of the first ECU 30 can be received by the second ECU 45, and when the first ECU 30 fails, the second ECU 45 can be configured to be allowed to operate.

In the above-mentioned first drive device 1, there are a plurality of combinations of operating points (torques) of the first motor 2R and the second motor 2L that can satisfy the torque required for the wheels 11R and 11L. Similarly, the second drive device 1'can satisfy the torque required for the wheels 39R and 39L, and the combination of the operating points of the motors 2R'and 2L' mounted on the second drive device 1'is There are multiple. In the following description, for convenience, a method of determining the operating points of the motors 2R and 2L for the first driving device 1 will be described, but the operation of the motors 2R'and 2L' mounted on the second driving device 1'will be described. The points can be set in the same way.

Explaining the combination of the operating points of the first motor 2R and the second motor 2L described above, when a predetermined torque T _req is required for the first drive device 1 during straight running, the first motor 2R and the second motor Running by outputting the same torque (torque in which the predetermined torque T _req is evenly distributed) from 2L (hereinafter referred to as the first running), or the predetermined torque from one motor (for example, the first motor 2R). It runs without outputting torque from the other motor (for example, the second motor 2L) while outputting T _req (hereinafter referred to as the second running), or from one motor (for example, the first motor 2R). A torque that is less than the _{predetermined torque T req and larger than the torque T req} / 2, which is half of the _{predetermined torque T req} , is output, and the insufficient motor is output from the other motor (for example, the second motor 2L) to travel. (Hereinafter referred to as the third run), or one motor (for example, the first motor 2R) _{outputs a torque larger than the predetermined torque T req} , and the other motor (for example, the second motor 2L) is surplus. It is possible to run by regenerating the torque of (hereinafter referred to as the fourth run). Further, among the above-mentioned third and fourth runs, the magnitude of the torque output from one of the motors 2R can be appropriately selected.

The relationship between the operating points (torques) of the above motors 2R and 2L is schematically shown in FIG. The solid line in FIG. 5 indicates the torque of the first motor 2R, the broken line indicates the torque of the second motor 2L, and the torque of the first motor 2R is gradually reduced from _{the predetermined torque T req as shown by the line with A1.} The torque of the second motor 2L gradually increases to _{a predetermined torque T req as shown by the line with A2.} The case where the motors 2R and 2L are controlled by the torque relationship between the first motor 2R and the second motor 2L as in the line with A1 and A2 corresponds to the third running. Further, as the torque of the first motor 2R is _{gradually increased from the predetermined torque T req} like the wire with C1, the torque of the second motor 2L like the wire with C2 increases the amount of regeneration. It gradually decreases as it does. The case where the motors 2R and 2L are controlled in relation to the torque between the first motor 2R and the second motor 2L as in the line with C1 and C2 corresponds to the fourth running. The case where the motors 2R and 2L are controlled at the intersection of A1 and A2 corresponds to the second running, and the case where the first motor 2R is controlled so that the torque of the second motor 2L becomes "0". However, it corresponds to the first run.

On the other hand, the efficiency of the first motor 2R and the second motor 2L changes according to the operating point determined by the rotation speed and the torque. This efficiency is obtained by dividing the output (power) of the motor by the electric power input to the motor. Therefore, for example, even when one motor 2R (2L) is driven at a good operating point, the efficiency of the other motor 2L (2R) deteriorates, so that the first drive device 1 as a whole The efficiency X may not be good. In other words, the power output from the first drive device 1 may be lower than the power output from the first power source 27.

Therefore, the driving force control device according to the embodiment of the present invention can satisfy the torque required for the first driving device 1, and the efficiency X of the first driving device 1 becomes good. It is configured to determine the torque.

First, a combination of the first motor 2R and the second motor 2L that can realize the required torque of the first drive device 1 is selected. Specifically, the torque of the first motor 2R is changed by a predetermined torque (for example, 1 Nm) from the minimum torque (for example, -200 Nm) to the maximum torque (for example, 200 Nm), and a plurality of first provisional torques T1 _pr To determine. Here, the reason why the torque of the first motor 2R is changed from the minimum torque by a predetermined torque is to cope with the case where the characteristics of the motors 2R and 2L are different.

Then, the torque of the second motor 2L is changed by a predetermined torque so as to satisfy _{the required torque T req} of the first drive device 1, _{and a plurality of second provisional torques T2 pr} are determined. Specifically, when the required torque T _req of the first drive device 1 is 100 Nm and the first provisional torque T1 _pr is 0 Nm, the second provisional torque T2 _pr is set to 100 Nm. If the first provisional torque T1 _pr is 80 Nm, the second provisional torque T2 _pr is defined as 20 Nm, and if the first provisional torque T1 _pr is 170 Nm, the second provisional torque T2 _pr is defined as -70 Nm. That is, a plurality of combinations of the torque of the first motor 2R and the torque of the second motor 2L that can satisfy _{the required torque T req} of the first drive device 1 are obtained. _{The required torque T req} of the first drive device 1 corresponds to the "total torque" in the embodiment of the present invention.

Then, the efficiency X of the first drive device 1 is calculated for each combination. The efficiency X of the first drive device 1 can be calculated by the following formula.
X = (T _req × N _am ) / ((T1 _pr / η1) × N1 _m + (T2 _pr / η2) × N2 _m )
In the above equation, N1 _m is the rotation speed of the first motor 2R, N2 _m is the rotation speed of the second motor 2L, and _Nam is the average value of the rotation speeds N1 _m and N2 _{m of the motors 2R and 2L.} Is. These can be calculated based on the signals of the sensors that detect the rotation speeds of the motors 2R and 2L, or the wheel speed sensors 40 and 41. Further, η1 in the above is the efficiency according to the operating point of the first motor 2R, and η2 is the efficiency according to the operating point of the second motor 2L. These efficiencies η1 and η2 are stored in advance in the first ECU 30 for each operating point of each of the motors 2R and 2L. That is, in the above equation, the output of the first drive device 1 _{is divided by the amount of energy required to satisfy the required torque T req} of the first drive device 1, that is, the amount of power to be output from the first power supply 27. There is.

Specifically, the required torque T _req of the first drive device 1 is 100 Nm, the rotation speeds N1 _m and N2 _{m of the} motors 2R and 2L are 2000 rpm (that is, when traveling straight), and the first provisional When the torque T1 _pr is 120 Nm, the second provisional torque T2 _pr is -20 Nm, the efficiency when outputting 120 Nm when the first motor 2R rotates at 2000 rpm is 0.98%, and when the second motor 2L rotates at 2000 rpm- The efficiency X of the first drive device 1 when the efficiency when outputting 20 Nm is 0.94% is
X = (100 x 2000) / ((120 / 0.98) x 2000 + (-20 / 0.94) x 2000)
Will be. As a result, the efficiency X of the first driving device 1 can be determined to be 0.988%.

Further, when the torques required for the left and right drive wheels 11R and 11L are different during turning, one motor connected to one drive wheel (for example, the right front wheel 11R) having a large required torque (for example, for example). _{The provisional torque T1 pr} of the first motor 2R) is determined in a range equal to or greater than the torque required for one drive wheel 11R, and the efficiency X of the first drive device 1 is calculated. This is because when the torque is transmitted via the clutch 22, the drive wheels are connected from one motor 2R (2L) having a large output torque to the other motor 2L (2R) having a small output torque. Since the torque is transmitted to 11L (11R)), _{it is a condition that the provisional torque T1 pr of} one motor 2R (2L) is equal to or more than the torque required for one drive wheel 11R. During turning, the outer ring becomes one of the drive wheels 11R. In the following description, for convenience, the case of turning running will be described as an example.

Including the above conditions, the efficiency X of the first drive device 1 is obtained, and then _{the clutch 22 is based on the difference between the provisional torque T1 pr} of the motor 2R connected to the outer ring and the torque required for the outer ring. The transmission torque capacity TC _{tr of} is obtained. _{That is, the transmission torque capacity TC tr} of the clutch 22 is obtained so as to reduce the torque transmitted to the outer ring and add the torque transmitted to the inner ring.

_{Specifically, when the torque T req} required for the first drive device 1 is 100 Nm and the torque required for the right front wheel 11R is 70 Nm, the first obtained according to the above will be described. _{When the first provisional torque T1 pr} that maximizes the efficiency X of the drive device 1 is 120 Nm and the second provisional torque T2 _pr is -20 Nm, the transmission torque capacity TC _tr of the clutch 22 is 50 (= 120-70). ) Nm.

As described above, the efficiency X of the first drive device 1 is calculated for each of a plurality of combinations of the first provisional torque T1 _pr and the second provisional torque T2 _{pr that can satisfy the required torque T req of the first drive device 1.} , Select the combination in which the efficiency X of the first drive device 1 is the best, that is, the amount of power output from the first power supply 27 is the smallest, and the first provisional torque T1 _pr and the second provisional torque T2 of the combination are selected. _{pr is defined as the target torques T1 ta} and T2 _ta of the motors 2R and 2L, and when the torques required for the left and right wheels 11R and 11L are different during turning, the motor 2R (2L) connected to the outer ring _{The transmission torque capacity TC tr} of the clutch 22 is determined by subtracting the torque required for the outer ring from the provisional torque T1 _pr (T2 _pr).

_{The target torques T1 ta} , T2 _ta of each of the above motors 2R and 2L and the transmission torque capacity TC _tr of the clutch 22 may be calculated at all times and obtained for each _{required torque T req of the first drive device 1.} A map that is calculated in advance and whose target torques T1 _ta , T2 _ta and transmission torque capacity TC _{tr correspond} to the required amount of the first drive device 1 (required torque T _req and rotation speed N _am ) and the required torque of the outer ring. You may memorize it in.

FIG. 6 shows an example of a map for straight running, and FIG. 7 shows an example of a map for turning running. In the example shown in FIG. 6, the required torque T _req of the first drive device 1 is taken in the row, and the rotation speed N _am is taken in the row. _{In addition, maps for turning are prepared for each required torque T req} of the first drive device 1, and these maps take the required torque of the outer ring in a row and the rotation speed _Nam in a row. There is. Note that FIG. 7 shows an example when the _{required torque T req is 100 Nm.}

FIG. 8 shows an example of control of the driving force control device according to the embodiment of the present invention. In the example shown in FIG. 8, first, the torque required for the vehicle Ve is calculated from the amount of accelerator operation by the driver, the vehicle speed, and the like (step S1). In the case of a so-called self-driving vehicle in which the driver can drive without operating the accelerator, the torque required for the vehicle Ve is calculated based on various sensors such as a radar mounted on the vehicle Ve. You may.

Then, based on the required torque of the vehicle Ve calculated in step S1, the torque required for the left wheel (required for the left front wheel 11L and the left rear wheel 39L) in consideration of running stability during turning or the like. The total torque value) and the torque required for the right wheel (the total torque required for the right front wheel 11R and the right rear wheel 39R) are calculated (step S2). Since this step S2 can be calculated based on a conventionally known stability factor or the like, the details of the calculation method will be omitted.

Following step S2, the torque required for the left front wheel 2L and the right front wheel 2R is calculated (step S3). In this step S3, for example, 30% of the torque required for the left wheel calculated in step S2 is calculated as the torque required for the left front wheel 2L, and is required for the right wheel calculated in step S2. 30% of the torque can be calculated as the torque required for the right front wheel 2R. This is because the installation load of the front wheels decreases and the installation load of the rear wheels increases during acceleration, so the ratio of torque output by the front wheels is set low and the ratio of torque output by the rear wheels is set high. Because. The detailed control contents for obtaining the torque required for the respective drive wheels 11R and 11L are described in, for example, Japanese Patent Application No. 2015-253254.

Then, the torque required for the left front wheel 2L and the right front wheel 2R calculated in step S3 is added _{to calculate the torque T req} required for the first drive device 1 (step S4).

_{Then, based on the torque T req} required for the first drive device 1 and the torque required for the left front wheel 2L or the right front wheel 2R, the target torque T1 _ta of the first motor 2R and the target torque of the second motor 2L The transmission torque capacity TC _tr of T2 _ta or the clutch 22 is calculated (step S5). This step S5 may be obtained by calculation as described above, or may be obtained from a map prepared in advance.

Then, it outputs a signal of the transmission torque capacity TC _tr of the first motor target torque target torque T1 _ta and the second motor 2L of 2R T2 _ta or clutch 22 which is calculated in step S5 to the motor 2R, 2L and the clutch 22 (Step S6), this routine is temporarily terminated.

_{As described above, a plurality of combinations of provisional torques T1 pr} and T2 _pr of the first motor 2R and the second motor 2L that can satisfy _{the required torque T req} of the first drive device 1 are selected, and among those combinations. _{The provisional torques T1 pr} and T2 _pr of the first motor 2R and the second motor 2L that maximize the efficiency X of the first drive device 1 _{are set, and the target torques T1 ta of} the first motor 2R and the second motor 2L are set. By defining it as T2 _ta , it is possible to suppress the output of excessive torque from the first drive device 1. That is, even in the case of the four-wheel drive vehicle shown in FIG. 2, since the target torques T1 _ta and T2 _{ta of the} motors 2R and 2L are set based on the torque required for the front wheels 11R and 11L, the front wheels 11R , 11L and the rear wheels 39R, 39L can suppress situations such as the directions of torques being output in opposite directions. That is, it is possible to suppress an increase in the slip amount of any of the drive wheels 11R, 11L, 39R, 39L. As a result, it is possible to suppress a decrease in the durability of each of the drive wheels 11R, 11L, 39R, 39L, and it is possible to suppress an increase in the power loss that occurs between the drive wheels and the road surface. In other words, the efficiency of the vehicle Ve as a whole can be improved.

Further, when the torques required for the left and right drive wheels 11R and 11L are different, the provisional torque of the motor connected to one of the drive wheels having the larger required torque is determined in a range equal to or larger than the torque required for the drive wheels. _{At the same time, by determining the transmission torque capacity TC tr} of the clutch 22 from the difference between the target torque of the motor connected to the drive wheels and the required torque of the drive wheels, it is the same as the required torque of the left and right wheels 11R and 11L. The torque can be output and the efficiency of the first drive device 1 can be improved. That is, even if the torques required for the left and right drive wheels 11R and 11L are different, the efficiency of the vehicle Ve as a whole can be improved.

Even if the motors having different characteristics between the first motor 2R and the second motor 2L described above are controlled in the same manner, the efficiency of the first drive device 1 can be improved. Further, when determining the transmission torque capacity TC _tr of the clutch 22, the first motor 2R is corrected after _{the required torque T req} of the first drive device 1 is corrected in consideration of the power loss due to the clutch 22 slipping. Or, the target torques T1 _ta and T2 _{ta of} the second motor 2L and the transmission torque capacity TC _tr of the clutch 22 may be determined.

1,1'... Drive device, 2R, 2L ... Drive motor (motor), 11R ... Right front wheel, 11L ... Left front wheel, 22 ... Clutch, 27 ... Power storage device, 30, 45 ... Electronic control device (ECU), 39R … Right rear wheel, 39L… Left rear wheel, Ve… Vehicle.

Claims (1)

Allows torque to be transmitted between the first motor connected to the drive wheels on the right side of the vehicle, the second motor connected to the drive wheels on the left side of the vehicle, and the first motor and the second motor. In a driving force control device including a driving device having a clutch capable of changing the transmission torque capacity and a power source for supplying power to the first motor and the second motor.
A controller for controlling the output torque, and the transmission torque capacity of the clutch of the said first motor the second motor,
The controller
Obtaining the total torque required for the drive device,
A plurality of combinations of the provisional torque of the first motor and the provisional torque of the second motor, wherein the total value of the output torque of the first motor and the output torque of the second motor becomes the total torque, are obtained.
Among the plurality of obtained combinations, the combination of the provisional torque of the first motor that minimizes the output power amount of the power supply and the provisional torque of the second motor is selected.
Torque is output from the first motor based on the provisional torque of the first motor of the selected combination, and torque is output from the second motor based on the provisional torque of the second motor of the selected combination. de-force,
The first required torque required for the right drive wheel and the second required torque required for the left drive wheel are obtained, respectively.
When the first required torque and the second required torque are different, the torque required for the first drive wheel having the larger required torque among the right drive wheel and the left drive wheel is determined. The transmission torque capacity of the clutch is obtained by subtracting from the provisional torque of the selected combination of the first control motor connected to the first drive wheel of the first motor and the second motor.
Driving force control apparatus characterized by has been configured to control the transmission torque capacity of the clutch based on the transmission torque capacity of the obtained.

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