Vehicle control device and computer program

Abstract

To provide a vehicle control device and a computer program capable of curbing an increase in a temperature of a drive motor without causing reductions in output of drive torque and regeneration efficiency.SOLUTION: A control device of a vehicle comprising a plurality of drive motors which are installed on wheels different from each other and are respectively capable of outputting drive torque and regenerative torque: predicts an occurrence of an output increase state in which output torque of either one of the drive motors positioned on a front side in a traveling direction of a vehicle becomes equal to or larger than rated output torque; and, when the output increase state is predicted to occur, limits the drive torque and the regenerative torque of the drive motor predicted to have output torque equal to or larger than the rated output torque to be equal to or less than the rated output torque until the drive motor is put into the output increase state.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle control device and a computer program. [Background technology]

[0002] A drive motor used as a drive source for a vehicle is required to have a rated output torque that allows it to continuously output a stable torque. If the drive motor continues to be operated at an output torque that exceeds the rated output torque, the temperature of the drive motor will rise, and there is a risk that the performance of the drive motor will deteriorate. In response to this, Patent Document 1 proposes an electric vehicle that performs regenerative power generation control of the motor generator when the electric vehicle is traveling downhill, so that sufficient power performance can be achieved when traveling on a flat road or uphill following the downhill traveling.

[0003] Specifically, Patent Document 1 discloses an electric vehicle that controls the division of total braking force output between hydraulic brakes and regenerative brakes using a motor generator, and controls the absolute value of regenerative torque when traveling downhill compared to when traveling on a flat road for the same brake operation.The electric vehicle in Patent Document 1 is configured to suppress regenerative braking force when traveling downhill and prevent a temperature rise in the drive motor, thereby providing sufficient power performance when traveling on a flat road or uphill immediately afterwards. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-167613 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the electric vehicle of Patent Document 1, regenerative braking force is limited, which may result in reduced regenerative efficiency. Furthermore, the drive motor generates heat not only during regeneration but also during driving, which affects output performance during driving and regeneration. In electric vehicles, the drive motor must output an output torque that matches the required drive torque, and it is necessary to suppress a rise in the drive motor's temperature and maintain the drive motor's performance even when the required drive torque is large.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a vehicle control device and computer program that can suppress the temperature rise of the drive motor without reducing the drive torque output and regenerative efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, according to one aspect of the present disclosure, there is provided a vehicle control device having a plurality of drive motors that are provided corresponding to different wheels and that are each capable of outputting drive torque for the vehicle as well as outputting regenerative torque, the vehicle control device comprising one or more processors and one or more memories communicably connected to the one or more processors, wherein the processor predicts an output increase state in which the output torque of any of the plurality of drive motors ahead in the direction of travel of the vehicle will exceed the rated output, and when an output increase state is predicted, the vehicle control device limits the drive torque and regenerative torque of the drive motor that will have an output greater than the rated output in the output increase state to below the rated output until the output increase state is reached.

[0008] Furthermore, in order to solve the above problem, according to yet another aspect of the present disclosure, there is provided a computer program applicable to a control device for a vehicle having a plurality of drive motors provided corresponding to different wheels, each capable of outputting drive torque for the vehicle and outputting regenerative torque, the computer program causing a processor to execute processing including predicting an output increase state in which the output torque of one of the plurality of drive motors ahead in the direction of travel of the vehicle will be equal to or greater than the rated output, and, when an output increase state is predicted, limiting the drive torque and regenerative torque of the drive motor that will have an output greater than the rated output in the output increase state to be equal to or less than the rated output until the output increase state is reached. [Effects of the Invention]

[0009] As described above, according to the present disclosure, it is possible to suppress the temperature rise of the traction motor without reducing the drive torque output and the regeneration efficiency. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a vehicle to which a vehicle drive system according to a first embodiment of the present disclosure can be applied. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of a drive system for a vehicle according to the embodiment; [Figure 3] 2 is a circuit diagram showing a configuration example of a drive system for a vehicle according to the embodiment; FIG. [Figure 4] 4 is a flowchart showing an example of the operation of the drive system of the vehicle according to the embodiment. [Figure 5] FIG. 4 is a schematic diagram illustrating an example of the configuration of a vehicle to which a vehicle drive system according to a second embodiment of the present disclosure can be applied. [Figure 6] FIG. 2 is a block diagram showing an example of the configuration of a drive system for a vehicle according to the embodiment; [Figure 7] 2 is a circuit diagram showing a configuration example of a drive system for a vehicle according to the embodiment; FIG. [Figure 8] 4 is a flowchart showing an example of the operation of the drive system of the vehicle according to the embodiment. [Figure 9] 4 is a flowchart showing an example of the operation of the drive system of the vehicle according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] <<1. First Embodiment>> <1-1. Example of vehicle configuration> First, an example of the overall configuration of a vehicle to which a vehicle control device according to a first embodiment of the present disclosure can be applied will be described.

[0013] Fig. 1 is a schematic diagram showing an example of the configuration of a vehicle 1 equipped with a vehicle control device 50 according to this embodiment. The vehicle 1 shown in Fig. 1 is a four-wheel vehicle equipped with a left front wheel 3LF, a right front wheel 3RF, a left rear wheel 3LR, and a right rear wheel 3RR (hereinafter, the left front wheel 3LF and the right front wheel 3RF may be collectively referred to as "front wheels 3F," and the left rear wheel 3LR and the right rear wheel 3RR may be collectively referred to as "rear wheels 3R"). The vehicle 1 is equipped with a front-wheel drive motor 11F and a rear-wheel drive motor 11R as drive power sources that generate drive torque for the vehicle 1. The front-wheel drive motor 11F and the rear-wheel drive motor 11R are configured to be able to drive the front wheels and the rear wheels independently, respectively.

[0014] The front-wheel drive motor 11F and the rear-wheel drive motor 11R are, for example, three-phase AC radial motors or axial gap motors. However, the number of phases is not particularly limited. The front-wheel drive motor 11F outputs drive torque that is transmitted to the left and right front wheels 3F via a differential mechanism 7F and a front-wheel drive shaft 5F. The rear-wheel drive motor 11R outputs drive torque that is transmitted to the left and right rear wheels 3R ​​via a differential mechanism 7R and a rear-wheel drive shaft 5R. Furthermore, when the vehicle 1 decelerates, the front-wheel drive motor 11F and the rear-wheel drive motor 11R have the function of receiving the rotational torque of the front wheels 3F or the rear wheels 3R ​​transmitted via the front-wheel drive shaft 5F or the rear-wheel drive shaft 5R to perform regenerative power generation. The drive and regeneration of the front-wheel drive motor 11F and the rear-wheel drive motor 11R are controlled by a control device 50.

[0015] The front-wheel drive motor 11F and the rear-wheel drive motor 11R each have a rated output torque that allows them to continuously output stable torque. The rated output torques of the front-wheel drive motor 11F and the rear-wheel drive motor 11R may be the same or different.

[0016] The vehicle 1 includes an inverter unit 13, a battery 20, and a control device 50 as a system for driving the front-wheel drive motor 11F and the rear-wheel drive motor 11R. The battery 20 is configured with a chargeable and dischargeable secondary battery. The battery 20 may be, for example, a lithium-ion battery rated at 200V, but the rated voltage and type of the battery 20 are not particularly limited. The battery 20 is connected to the front-wheel drive motor 11F and the rear-wheel drive motor 11R via the inverter unit 13, and stores power to be supplied to the front-wheel drive motor 11F and the rear-wheel drive motor 11R. The battery 20 is provided with a battery management device 21 that detects the open-circuit voltage, output voltage, battery temperature, etc. of the battery 20 and sends these to the control device 50.

[0017] The inverter unit 13 includes a first inverter circuit that controls the operation of the front-wheel drive motor 11F and a second inverter circuit that controls the operation of the rear-wheel drive motor 11R. The first inverter circuit converts DC power swept from the battery 20 into three-phase AC power and supplies it to the stator of the front-wheel drive motor 11F. The first inverter circuit also converts three-phase AC power regenerated by the front-wheel drive motor 11F into DC power and charges the battery 20. Similarly, the second inverter circuit converts DC power swept from the battery 20 into three-phase AC power and supplies it to the stator of the rear-wheel drive motor 11R. The second inverter circuit also converts three-phase AC power regenerated by the rear-wheel drive motor 11R into DC power and charges the battery 20. The operation of the inverter unit 13 is controlled by a control device 50.

[0018] A converter circuit for boosting the voltage may be provided between the battery 20 and the inverter circuit.

[0019] The control device 50 functions as a device that controls the driving of the front wheel drive motor 11F and the rear wheel drive motor 11R by having one or more processors execute a computer program. The computer program is a computer program that causes the processor to execute the operations to be performed by the control device 50, which will be described later. The computer program executed by the processor may be recorded on a recording medium that functions as a storage unit (memory) 53 provided in the control device 50, or may be recorded on a recording medium built into the control device 50 or any recording medium that can be externally attached to the control device 50.

[0020] Recording media for recording computer programs include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs (Compact Disk Read Only Memory), DVDs (Digital Versatile Disks), SSDs (Solid State Drives), and Blu-ray (registered trademark), magneto-optical media such as floptical disks, memory elements such as RAMs and ROMs, and flash memories such as USB (Universal Serial Bus) memories, as well as other media capable of storing programs.

[0021] The control device 50 is connected to an ambient environment sensor 31, a vehicle state sensor 33, and a GNSS (Global Navigation Satellite System) sensor 35 via a dedicated line or communication means such as a CAN (Controller Area Network) or a LIN (Local Internet). The control device 50 is also connected to an inverter unit 13 via a dedicated line or communication means such as a CAN or a LIN. The functional configuration of the control device 50 will be described in detail later.

[0022] The surrounding environment sensor 31 detects the surrounding environment of the vehicle 1. In this embodiment, the surrounding environment sensor 31 is configured to be able to detect at least the shape of the road ahead of the vehicle 1. In this embodiment, the vehicle 1 is equipped with front imaging cameras 31LF, 31RF and a LiDAR (Light Detection And Ranging) 31S as the surrounding environment sensor 31.

[0023] The front imaging cameras 31LF, 31RF capture images of the area in front of the vehicle 1 and generate image data. The front imaging cameras 31LF, 31RF are equipped with imaging elements such as CCD (Charged-Coupled Devices) or CMOS (Complementary Metal-Oxide-Semiconductor), and transmit the generated image data to the control device 50. In the vehicle 1 shown in FIG. 1, the front imaging cameras 31LF, 31RF are configured as stereo cameras including a pair of left and right cameras, but may also be monocular cameras. In addition to the front imaging cameras 31LF, 31RF, the vehicle 1 may also be equipped with a rear imaging camera that is provided, for example, at the rear of the vehicle 1 and captures images of the area behind.

[0024] The LiDAR 31S transmits optical waves and receives reflected waves of the optical waves, and detects obstacles, the distance to the obstacles, and the positions of the obstacles based on the time between transmitting the optical waves and receiving the reflected waves. The LiDAR 31S transmits the detection data to the control device 50. The vehicle 1 may be equipped with one or more sensors, instead of or in addition to the LiDAR 31S, of a radar sensor such as a millimeter-wave radar and an ultrasonic sensor as an ambient environment sensor for acquiring information about the ambient environment.

[0025] The vehicle state sensor 33 is composed of one or more sensors that detect the operating state and behavior of the vehicle 1. The vehicle state sensor 33 includes at least one of a steering angle sensor, an accelerator position sensor, a brake stroke sensor, a brake pressure sensor, or an engine rotation speed sensor, and detects the operating state of the vehicle 1, such as the steering angle of the steering wheel or steered wheels, the accelerator opening, the amount of brake operation, or the engine rotation speed. The vehicle state sensor 33 also includes at least one of a vehicle speed sensor, an acceleration sensor, or an angular velocity sensor, and detects the behavior of the vehicle, such as the vehicle speed, longitudinal acceleration, lateral acceleration, and yaw rate. The vehicle state sensor 33 transmits a sensor signal including the detected information to the control device 50.

[0026] The GNSS sensor 35 receives satellite signals transmitted from a plurality of satellites and detects the position of the GNSS sensor 35, that is, the position of the vehicle 1. The GNSS sensor 35 transmits the detected position information of the vehicle 1 to the control device 50.

[0027] <1-2.Control device> Next, the vehicle control device 50 according to this embodiment will be described in detail.

[0028] (1-2-1. Configuration example) FIG. 2 is a block diagram showing an example of the configuration of the control device 50. The control device 50 includes a processing unit 51 and a storage unit 53. The processing unit 51 is configured with one or more processors such as CPUs. Part or all of the processing unit 51 may be configured with updatable firmware or the like, or may be a program module or the like executed by commands from the CPU or the like. The storage unit 53 is configured with memory such as RAM (Random Access Memory) or ROM (Read Only Memory). However, the number and type of storage units 53 are not particularly limited. The storage unit 53 stores information such as computer programs executed by the processing unit 51, various parameters used in arithmetic processing, detection data, and arithmetic results.

[0029] (1-2-2. Functional configuration) The processing unit 51 of the control device 50 includes a surrounding environment detection unit 61, an output increase prediction unit 63, an output limiting unit 65, and a motor control unit 67. Each of these units may have a function realized by a processor such as a CPU executing a computer program, or may be partially configured by analog circuits. Below, the function of each unit of the processing unit 51 will be briefly described, followed by a description of specific processing operations.

[0030] (Ambient environment detection section) The surrounding environment detection unit 61 detects the surrounding environment of the vehicle 1 based on the detection data transmitted from the surrounding environment sensor 31. Specifically, the surrounding environment detection unit 61 calculates the type, size (width, height, and depth), position, speed, distance from the vehicle 1 to the obstacle, and relative speed between the vehicle 1 and the obstacle of each obstacle present around the vehicle 1. The detected obstacles include other moving vehicles, parked vehicles, pedestrians, bicycles, side walls, curbs, buildings, utility poles, traffic signs, traffic signals, natural objects, and any other objects present around the vehicle 1. In this embodiment, the surrounding environment detection unit 61 acquires information on at least the shape of the road ahead of the vehicle 1. The information on the road shape includes information on the gradient of the road and the radius of curvature of curves.

[0031] Furthermore, the surrounding environment detection unit 61 may refer to high-precision map data and acquire information on the shape of the road ahead in the traveling direction of the vehicle 1 based on information on the position of the vehicle 1. Specifically, the surrounding environment detection unit 61 identifies the position and traveling direction of the vehicle 1 on the high-precision map data based on the position information of the vehicle 1 transmitted from the GNSS sensor 35, and acquires information on the shape of the road ahead in the traveling direction of the vehicle 1. Data on road gradients and curvature radii are recorded in association with the high-precision map data, and the surrounding environment detection unit 61 acquires this information on the road shape.

[0032] (Power increase prediction section) The output increase prediction unit 63 predicts an output increase state in which the output torque of either the front-wheel drive motor 11F or the rear-wheel drive motor 11R is increased to or above the rated output ahead of the vehicle 1 in the traveling direction. Specifically, the output increase prediction unit 63 predicts an output increase state in which the output torque of either the front-wheel drive motor 11F or the rear-wheel drive motor 11R is increased to or above the rated output based on information about the shape of the road ahead of the vehicle 1 in the traveling direction acquired by the surrounding environment detection unit 61. For example, when there is an uphill road ahead of the vehicle 1 in the traveling direction, the output increase prediction unit 63 predicts an output increase state in which the drive torque of the rear-wheel drive motor 11R will be increased to or above the rated output. In this case, the output increase prediction unit 63 may predict the output increase state based on the gradient of the uphill road and the vehicle speed, or may predict the output increase state based on the results of calculating target drive torques for the front-wheel drive motor 11F and the rear-wheel drive motor 11R.

[0033] (Output limiter) When the output increase prediction unit 63 predicts an output increase state, the output limiting unit 65 limits the drive torque and regenerative torque of the front-wheel drive motor 11F or the rear-wheel drive motor 11R, which would be greater than or equal to the rated output in the output increase state, to less than or equal to the rated output until the output increase state is reached. In the example of the uphill road described above, when an output increase state is predicted in which the target drive torque of the rear-wheel drive motor 11R is greater than or equal to the rated output, the output limiting unit 65 sets the drive torque and regenerative torque of the rear-wheel drive motor 11R to be less than or equal to the rated output until the vehicle 1 reaches the uphill road. This suppresses the rise in temperature of the rear-wheel drive motor 11R until the vehicle 1 reaches the uphill road, and can lower the temperature limit of the rear-wheel drive motor 11R while traveling uphill.

[0034] For example, the output limiting unit 65 changes the ratio at which the target torque for the entire vehicle 1 is distributed to the front-wheel drive motor 11F and the rear-wheel drive motor 11R from the basic ratio used in normal mode, which does not limit output, and limits the drive torque and regenerative torque of the rear-wheel drive motor 11R to a rated output or less. Furthermore, when limiting the drive torque and regenerative torque of the rear-wheel drive motor 11R to a rated output or less, the output limiting unit 65 may set upper limits for the drive torque and regenerative torque according to the gradient of the uphill road. In other words, the greater the estimated drive torque while the vehicle 1 is traveling uphill, the more the output of the rear-wheel drive motor 11R is limited until the vehicle 1 reaches the uphill road, thereby suppressing an increase in the temperature of the rear-wheel drive motor 11R.

[0035] (Motor control unit) The motor control unit 67 controls the drive and regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R. While the drive torque and regenerative torque of the front wheel drive motor 11F and the rear wheel drive motor 11R are not limited by the output limiting unit 65, the motor control unit 67 controls the drive and regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R in normal mode.

[0036] Specifically, the motor control unit 67 sets target drive torques for the front-wheel drive motor 11F and the rear-wheel drive motor 11R based on the required drive torque of the vehicle 1. The motor control unit 67 controls the operation of switching elements provided in the first inverter circuit and the second inverter circuit of the inverter unit 13 to output drive torques from the front-wheel drive motor 11F and the rear-wheel drive motor 11R. The required drive torque is calculated based on the amount of accelerator pedal operation during manual driving. Furthermore, the required drive torque is calculated based on a required acceleration obtained by calculation during autonomous driving.

[0037] At this time, the motor control unit 67 sets the ratio between the target drive torque of the front-wheel drive motor 11F and the target drive torque of the rear-wheel drive motor 11R to a preset basic ratio, for example. The basic ratio is set, for example, within a range of 4:6 to 6:4 depending on the desired driving performance. Furthermore, when the vehicle 1 is traveling uphill, the motor control unit 67 increases the target drive torque ratio of the rear-wheel drive motor 11R to compensate for the greater load of the vehicle weight on the rear wheels 3R. For example, the motor control unit 67 sets the target drive torque ratio of the rear-wheel drive motor 11R to a larger value the greater the gradient of the uphill road.

[0038] The motor control unit 67 also sets target regenerative torques for the front-wheel drive motor 11F and the rear-wheel drive motor 11R based on the required braking torque of the vehicle 1. The motor control unit 67 controls the operation of switching elements provided in the first inverter circuit and the second inverter circuit of the inverter unit 13 to control power generation by the front-wheel drive motor 11F and the rear-wheel drive motor 11R and generate regenerative torque. The required braking torque is calculated based on the amount of brake pedal operation during manual driving. The required braking torque is also calculated based on a required deceleration obtained by calculation during autonomous driving.

[0039] At this time, the motor control unit 67 sets the ratio between the target regenerative torque of the front-wheel drive motor 11F and the target regenerative torque of the rear-wheel drive motor 11R to a preset basic ratio, for example. The basic ratio is set to 5:5, for example. Furthermore, the larger the required braking torque, the larger the target regenerative torque ratio of the front-wheel drive motor 11F, corresponding to the load of the vehicle weight on the front wheels 3F. Similarly, when the vehicle 1 decelerates while traveling downhill, the control device 50 increases the target regenerative torque ratio of the front-wheel drive motor 11F, corresponding to the load of the vehicle weight on the front wheels 3F. For example, the motor control unit 67 sets the target regenerative torque ratio of the front-wheel drive motor 11F to be larger the greater the gradient of the downhill road.

[0040] Furthermore, the motor control unit 67 controls the driving and regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R in the output limited mode while the driving torque and regenerative torque of the front wheel drive motor 11F or the rear wheel drive motor 11R are limited by the output limiting unit 65. Specifically, the motor control unit 67 sets the upper limit of the target driving torque or target regenerative torque of the front wheel drive motor 11F or the rear wheel drive motor 11R whose output has been limited to be equal to or less than the rated output torque, and if the target driving torque or target regenerative torque of the motor whose output has been limited, calculated using a calculation method in normal mode, exceeds the rated output, the excess torque is distributed to the other motor.

[0041] The motor control unit 67 controls the drive of the inverter unit 13 based on the drive torque and regenerative torque of the front wheel drive motor 11F or the rear wheel drive motor 11R calculated in normal mode or output limited mode, respectively, and controls the drive or regeneration of the front wheel drive motor 11F or the rear wheel drive motor 11R.

[0042] <1-3. Processing operation example> So far, an example of the configuration of the vehicle control device 50 according to this embodiment has been described. Next, an example of the processing operation of the vehicle control device 50 will be described with reference to a flowchart.

[0043] 3 is a flowchart showing the control processing operation of the front wheel drive motor 11F and the rear wheel drive motor 11R by the vehicle control device 50 according to this embodiment. In the following explanation, an example will be described in which an uphill road exists ahead in the traveling direction of the vehicle 1, and the output of the rear wheel drive motor 11R is limited before the vehicle 1 starts traveling on the uphill road.

[0044] First, when the drive system of the vehicle 1 is started (step S11), the processing unit 51 acquires information about the road shape ahead in the traveling direction of the vehicle 1 (step S13). Specifically, the surrounding environment detection unit 61 detects measurement objects that can recognize the road shape, such as white lines, curbs, and guardrails on the road ahead, based on detection data transmitted from the front-facing imaging cameras 31LF, 31RF and the LiDAR 31S. The surrounding environment detection unit 61 also calculates the distance to each of multiple measurement objects that can recognize the road shape and are present within the measurement range of the surrounding environment sensor 31. The surrounding environment detection unit 61 calculates the gradient of the road based on the information about the distance to each calculated position.

[0045] The surrounding environment detection unit 61 may identify the position and traveling direction of the vehicle 1 on the high-precision map data based on the position data of the vehicle 1 transmitted from the GNSS sensor 35, and may calculate the gradient of the road ahead in the traveling direction of the vehicle 1. The high-precision map data may be stored in the storage unit 53, or may be stored in an external server connectable via wireless communication means.

[0046] Next, the output increase prediction unit 63 determines whether or not there is an uphill road ahead in the traveling direction of the vehicle 1 (step S15). Specifically, the output increase prediction unit 63 determines whether or not an uphill road exceeding a predetermined gradient continues for a predetermined distance or more, based on the road shape information acquired in step S13. The predetermined gradient is set to determine a state in which the required drive torque increases when traveling on an uphill road, and may be set arbitrarily within a range of, for example, 30 to 45%. Furthermore, the predetermined distance may be set according to the magnitude of the gradient, so that the greater the gradient, the shorter the distance.

[0047] If it is determined that there is no uphill road ahead (S15 / No), the motor control unit 67 sets the target torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R in normal mode without limiting the output (step S25). Specifically, the motor control unit 67 sets a target torque for the entire vehicle 1 based on information on the vehicle speed, accelerator pedal operation amount, and brake pedal operation amount transmitted from the vehicle state sensor 33, and distributes the target torque to the front-wheel drive motor 11F and the rear-wheel drive motor 11R to set the target torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R.

[0048] When the accelerator pedal is depressed, the target drive torque is set based on the accelerator pedal depression amount and the vehicle speed, and the target drive torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R is set. Also, when the accelerator pedal is suddenly released or the brake pedal is depressed, the target regenerative torque is set based on the speed at which the accelerator pedal is released or the brake pedal depression amount, and the target regenerative torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R is set. The target drive torque or target regenerative torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R, which is set in normal mode, may exceed the rated output torque of the front-wheel drive motor 11F and the rear-wheel drive motor 11R, depending on the driving conditions.

[0049] Next, the motor control unit 67 controls the drive or regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R based on the set target drive torque or target regenerative torque (step S26). Specifically, the motor control unit 67 controls the drive of the first inverter circuit and the second inverter circuit of the inverter unit 13 based on the target drive torque or target regenerative torque, causing the front wheel drive motor 11F and the rear wheel drive motor 11R to output drive torque or regenerative torque.

[0050] On the other hand, if it is determined in step S15 that an uphill road is present ahead (S15 / Yes), the output increase prediction unit 63 estimates the drive torque of each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R while traveling uphill (step S17). For example, the output increase prediction unit 63 predicts the driver's accelerator operation, assuming that the current vehicle speed of the vehicle 1 detected by the vehicle state sensor 33 will be maintained, and estimates the drive torque of the vehicle 1. The output increase prediction unit 63 also calculates the drive torque (estimated drive torque) when the estimated drive torque is distributed to the front-wheel drive motor 11F and the rear-wheel drive motor 11R in accordance with the normal mode setting.

[0051] Next, the output increase prediction unit 63 determines whether there is a motor whose estimated drive torque is equal to or greater than the rated output torque (step S19). The rated output torques of the front-wheel drive motor 11F and the rear-wheel drive motor 11R are determined from specification data and stored in advance in the storage unit 53. The output increase prediction unit 63 compares the estimated drive torques of the front-wheel drive motor 11F and the rear-wheel drive motor 11R with the rated output torque, and determines whether the estimated drive torque of either the front-wheel drive motor 11F or the rear-wheel drive motor 11R is equal to or greater than the rated output torque. If traveling uphill is planned, it may be sufficient to determine only whether the estimated drive torque of the rear-wheel drive motor 11R is equal to or greater than the rated output torque.

[0052] If it is determined that there is no motor whose estimated drive torque is equal to or greater than the rated output torque (S19 / No), the motor control unit 67 sets target torques for the front wheel drive motor 11F and the rear wheel drive motor 11R in normal mode (step S25).The motor control unit 67 also controls the drive or regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R based on the set target torques (step S26).

[0053] On the other hand, if it is determined that there is a motor whose estimated drive torque is equal to or greater than the rated output torque (S19 / Yes), the output limiting unit 65 limits the output of the motor predicted to be equal to or greater than the rated output torque (step S21). Specifically, when the output limiting unit 65 predicts that the estimated drive torque of the rear-wheel drive motor 11R will be equal to or greater than the rated output torque, the output limiting unit 65 sets the upper limit of the output torque of the rear-wheel drive motor 11R during the period until the vehicle reaches an uphill slope so that the upper limit is equal to or less than the rated output torque. For example, the output limiting unit 65 reduces the output torque of the rear-wheel drive motor 11R by reducing the ratio of torque allocated to the rear-wheel drive motor 11R compared to the setting in the normal mode. Alternatively, the output limiting unit 65 may set the rated output torque of the rear-wheel drive motor 11R as the upper limit of the target torque. In this way, the drive torque and regenerative torque of the rear-wheel drive motor 11R are set so as not to exceed the rated output torque during the period until the vehicle reaches an uphill slope.

[0054] Furthermore, when limiting the drive torque and regenerative torque of the rear-wheel drive motor 11R to be equal to or less than the rated output, the output limiting unit 65 may set upper limits for the drive torque and regenerative torque depending on the gradient of the uphill road. In other words, the larger the estimated drive torque while the vehicle 1 is traveling uphill, the smaller the upper limit for the output of the rear-wheel drive motor 11R until the vehicle 1 reaches the uphill road. This increases the reliability of lowering the ultimate temperature of the rear-wheel drive motor 11R while traveling uphill.

[0055] Furthermore, if the output of the rear-wheel drive motor 11R is set to be limited when the temperature of the rear-wheel drive motor 11R or the temperature of the second inverter circuit controlling the rear-wheel drive motor 11R reaches a predetermined limit temperature, the output limiting unit 65 may limit the output of the rear-wheel drive motor 11R so that the temperature of the rear-wheel drive motor 11R or the temperature of the second inverter circuit does not reach the predetermined limit temperature while the vehicle 1 is traveling uphill. For example, the output limiting unit 65 may predict the amount of heat generated by the rear-wheel drive motor 11R or the second inverter circuit while the vehicle 1 is traveling uphill, and limit the drive torque and regenerative torque of the rear-wheel drive motor 11R to be equal to or less than the rated output until the vehicle 1 reaches the uphill road so that the temperature of the rear-wheel drive motor 11R does not reach the predetermined limit temperature while the vehicle 1 is traveling uphill.

[0056] Specifically, the amount of heat generated by the rear-wheel drive motor 11R while the vehicle 1 is traveling uphill can be calculated based on the rotation speed and output torque of the rear-wheel drive motor 11R. Specifically, power loss occurs in the rear-wheel drive motor 11R depending on the rotation speed and output torque of the rear-wheel drive motor 11R, and the amount of heat generated varies depending on the power loss. The relationship between the rotation speed and output torque of the rear-wheel drive motor 11R and the power loss or amount of heat generated by the rear-wheel drive motor 11R is stored in advance as the characteristics of the rear-wheel drive motor 11R. The output limiting unit 65 calculates the amount of heat generated by the rear-wheel drive motor 11R based on the rotation speed and output torque of the rear-wheel drive motor 11R that are assumed based on the vehicle speed setting when traveling uphill. The output limiting unit 65 converts the calculated amount of heat generated by the rear-wheel drive motor 11R into a temperature rise of the rear-wheel drive motor 11R. The output limiting unit 65 limits the driving torque or regenerative torque of the rear wheel drive motor 11R until the vehicle 1 reaches an uphill road so that the temperature of the rear wheel drive motor 11R is maintained at or below the temperature obtained by subtracting the temperature rise from the limit temperature when the vehicle 1 reaches the uphill road.

[0057] Similarly, the heat generation amount of the second inverter circuit while the vehicle 1 is traveling uphill can be calculated based on the rotation speed and output torque of the rear-wheel drive motor 11R. Specifically, power loss occurs in the second inverter circuit depending on the rotation speed and output torque of the rear-wheel drive motor 11R, and the heat generation amount changes depending on the power loss. The relationship between the rotation speed and output torque of the rear-wheel drive motor 11R and the power loss or heat generation amount in the second inverter circuit is pre-stored as the characteristics of the second inverter circuit. The output limiting unit 65 calculates the heat generation amount of the second inverter circuit based on the rotation speed and output torque of the rear-wheel drive motor 11R estimated from the vehicle speed setting when traveling uphill. The output limiting unit 65 converts the calculated heat generation amount of the second inverter circuit into a temperature rise of the second inverter circuit. The output limiting unit 65 then limits the drive torque or regenerative torque of the rear-wheel drive motor 11R until the vehicle 1 reaches the uphill road so that the temperature of the second inverter circuit is maintained at or below the limit temperature minus the temperature rise when the vehicle 1 reaches the uphill road.

[0058] Next, the motor control unit 67 sets the respective target torques in an output limit mode that limits the output of the rear-wheel drive motor 11R when the estimated drive torque is predicted to be equal to or greater than the rated output torque (step S23). For example, the motor control unit 67 sets the target drive torque or target regenerative torque for the front-wheel drive motor 11F and the rear-wheel drive motor 11R based on the torque distribution ratio for the output limit mode changed in step S21. Then, if the calculated target drive torque or target regenerative torque for the rear-wheel drive motor 11R exceeds the rated output torque of the rear-wheel drive motor 11R or an upper limit set in accordance with the gradient of an uphill road, the motor control unit 67 distributes the torque that exceeds the rated output torque or the upper limit to the front-wheel drive motor 11F.

[0059] Alternatively, the motor control unit 67 may calculate the target drive torque or target regenerative torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R in normal mode, as in step S25, and then correct the target drive torque or target regenerative torque. For example, if the calculated target drive torque or target regenerative torque for the rear-wheel drive motor 11R exceeds the rated output torque of the rear-wheel drive motor 11R, the motor control unit 67 allocates the torque that exceeds the rated output torque to the front-wheel drive motor 11F.

[0060] Next, similar to step S26, the motor control unit 67 controls the driving or regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R based on the set target driving torque or target regenerative torque (step S24).

[0061] Next, the output increase prediction unit 63 determines whether or not the vehicle 1 has reached an uphill road (step S27). For example, the output increase prediction unit 63 may determine whether or not the vehicle 1 has reached the uphill road detected in step S15 based on information about the surrounding environment transmitted from the surrounding environment sensor 31, or may determine whether or not the vehicle 1 has reached an uphill road based on information about the position of the vehicle 1 on the high-precision map data.

[0062] If it is determined that the vehicle 1 has not reached an uphill road (S27 / No), the motor control unit 67 repeats setting the target torque in the output limit mode (step S23) and controlling the drive or regeneration of the front-wheel drive motor 11F and the rear-wheel drive motor 11R (step S24). On the other hand, if it is determined that the vehicle 1 has reached an uphill road (S27 / Yes), or if the drive or regeneration control of the front-wheel drive motor 11F and the rear-wheel drive motor 11R has been executed in step S26, the processing unit 51 determines whether the vehicle's drive system has stopped (step S29). If the drive system has not stopped (S29 / No), the process returns to step S13 and repeats the above-described processing. On the other hand, if the drive system has stopped (S29 / Yes), the processing unit 51 ends the control processing for the front-wheel drive motor 11F and the rear-wheel drive motor 11R.

[0063] FIG. 4 is an explanatory diagram showing the application range of the output limit mode. Suppose that while the vehicle 1 is traveling on a flat road, at time t1, the control device 50 detects an uphill road ahead in the traveling direction and determines that the estimated drive torque while the vehicle 1 is traveling on the uphill road will be equal to or greater than the rated output torque. In this case, the mode for setting the target torque for the front-wheel drive motor 11F and the rear-wheel drive motor 11R is switched from normal mode to output limited mode. The output limited mode continues until time t2 when the vehicle 1 reaches the uphill road, at which time the mode for setting the target torque for the front-wheel drive motor 11F and the rear-wheel drive motor 11R is switched back from output limited mode to normal mode.

[0064] As a result, from time t1 when an uphill road is detected until time t2 when the uphill road is reached, the output torque of the rear-wheel drive motor 11R is limited to a value equal to or less than the rated output, thereby suppressing an increase in the temperature of the rear-wheel drive motor 11R. Therefore, the vehicle 1 can enter an uphill road while maintaining a margin of power up to a temperature at which the output of the rear-wheel drive motor 11R would decrease. After time t2 when the vehicle 1 reaches the uphill road, the limitation on the output torque of the rear-wheel drive motor 11R is released, ensuring the required drive torque for traveling uphill. Furthermore, because traveling uphill begins when the temperature of the rear-wheel drive motor 11R is relatively low, the time it takes for the rear-wheel drive motor 11R to reach a temperature at which the output of the rear-wheel drive motor 11R would decrease can be delayed, preventing a decrease in performance of the rear-wheel drive motor 11R while traveling uphill.

[0065] <1-4. Effects> As described above, the vehicle control device 50 according to the first embodiment of the present disclosure is applied to a vehicle 1 equipped with a front-wheel drive motor 11F and a rear-wheel drive motor 11R. When an uphill road is present ahead in the vehicle 1's traveling direction, the control device 50 determines whether the estimated drive torque of the rear-wheel drive motor 11R will be equal to or greater than the rated output torque of the rear-wheel drive motor 11R while traveling uphill. Furthermore, if the estimated drive torque of the rear-wheel drive motor 11R while traveling uphill is equal to or greater than the rated output torque of the rear-wheel drive motor 11R, the control device 50 limits the output torque of the rear-wheel drive motor 11R to be equal to or less than the rated output torque until the vehicle 1 reaches the uphill road. This suppresses the temperature rise of the rear-wheel drive motor 11R until the vehicle 1 reaches the uphill road, thereby lowering the temperature limit of the rear-wheel drive motor 11R while traveling uphill. Therefore, it is possible to reduce the risk that the output of the rear wheel drive motor 11R will decrease while the vehicle 1 is traveling uphill, resulting in a shortage of drive torque for the entire vehicle 1.

[0066] Furthermore, in the vehicle control device 50 according to this embodiment, the target torque distribution ratio between the front wheel drive motor 11F and the rear wheel drive motor 11R is changed, and the output of the rear wheel drive motor 11R is limited until the vehicle 1 reaches an uphill road, thereby making it possible to limit the output of the rear wheel drive motor 11R through relatively simple calculation processing.

[0067] Furthermore, in the vehicle control device 50 according to this embodiment, by setting an upper limit for the target torque of the rear-wheel drive motor 11R until the vehicle 1 reaches an uphill road based on the gradient of the uphill road, it is possible to lower the temperature limit of the rear-wheel drive motor 11R while the vehicle 1 is traveling uphill. Furthermore, the distribution ratio of the target torque to the front-wheel drive motor 11F and the rear-wheel drive motor 11R until the vehicle 1 reaches an uphill road is not changed more than necessary from the distribution ratio in normal mode, thereby preventing a deterioration in driving performance.

[0068] In the first embodiment described above, an example of a vehicle 1 having one front-wheel drive motor 11F on the front wheel side and one rear-wheel drive motor 11R on the rear wheel side was described. However, the vehicle 1 to which the control device 50 according to this embodiment can be applied is not limited to this example. The control device 50 according to this embodiment can also be applied to a vehicle having drive motors corresponding to the left and right wheels on at least one of the front wheel side or the rear wheel side. When two drive motors are provided on the rear wheel side, a similar effect can be achieved by using these two drive motors as rear-wheel drive motors and limiting their output until the vehicle reaches an uphill slope. In this case, it is desirable to limit the output of the left and right drive motors as a pair to prevent a difference in torque between the left and right wheels.

[0069] <<2. Second Embodiment>> Next, a second embodiment of the present disclosure will be described. In the second embodiment, when there is a curve ahead of the vehicle 1 in the direction of travel, the control device predicts the output of the drive motor at the exit of the curve, and when it is predicted that the drive torque of the front wheel drive motor 11F or the rear wheel drive motor 11R will be greater than or equal to the rated output torque when accelerating at the exit of the curve, the control device is configured to limit the regenerative torque of the drive motor when entering the curve to less than the rated output.

[0070] A vehicle 1 to which the control device according to this embodiment can be applied has the same configuration as the vehicle 1 described in the first embodiment. The basic configuration of the control device is also the same as the configuration of the control device 50 shown in Fig. 2. Below, the differences between the vehicle control device according to this embodiment and the first embodiment will be described.

[0071] <2-1. Example of control device configuration> In this embodiment, when there is a curve ahead in the traveling direction of the vehicle 1, the output increase prediction unit 63 predicts an output increase state in which the drive torque of the front-wheel drive motor 11F or the rear-wheel drive motor 11R will be equal to or greater than the rated output at the exit of the curve. For example, the output increase prediction unit 63 estimates the speed after deceleration when the vehicle 1 passes through the curve based on the radius of curvature of the curve, and estimates the drive torque of the front-wheel drive motor 11F and the rear-wheel drive motor 11R on the assumption that the speed will return to the speed before entering the curve at the exit of the curve.

[0072] Whether or not there is a curve ahead in the traveling direction of the vehicle 1 may be determined by identifying the position and traveling direction of the vehicle 1 on high-precision map data based on the position data of the vehicle 1 transmitted from the GNSS sensor 35, and by referring to data on the curvature radius of the road ahead in the traveling direction. Alternatively, whether or not there is a curve ahead in the traveling direction may be determined based on detection data transmitted from the surrounding environment sensor 31. In this case, the surrounding environment detection unit 61 also calculates the curvature radius of the road based on information on the detected measurement object. The "curve exit" refers to the area beyond the inflection point where the curvature radius of the curve is minimum.

[0073] Furthermore, when the output increase prediction unit 63 predicts an output increase state, the output limiting unit 65 sets the regenerative torque of the drive motor, which is predicted to exceed the rated output torque when the vehicle 1 decelerates as it passes through a curve, to be limited to less than the rated output. This suppresses the temperature rise of the drive motor until the vehicle 1 reaches the exit of the curve, and lowers the temperature limit of the drive motor when accelerating at the exit of the curve. The method of limiting the target regenerative torque of the drive motor may be the same as the method of limiting the drive torque and regenerative torque of the rear-wheel drive motor 11R to less than the rated output in the first embodiment.

[0074] <2-2. Processing operation example> 5 is a flowchart showing the control processing operation of the front-wheel drive motor 11F and the rear-wheel drive motor 11R by the vehicle control device 50 according to this embodiment. In the following explanation, an example will be described in which there is a curve ahead in the traveling direction of the vehicle 1, and the output of the front-wheel drive motor 11F or the rear-wheel drive motor 11R is limited when the vehicle 1 is decelerating as it passes through the curve.

[0075] First, when the drive system of the vehicle 1 is started (step S31), the surrounding environment detection unit 61 of the processing unit 51 acquires information about the shape of the road ahead in the traveling direction of the vehicle 1 (step S33). Specifically, the surrounding environment detection unit 61 may identify the position and traveling direction of the vehicle 1 on the high-precision map data based on the position data of the vehicle 1 transmitted from the GNSS sensor 35, and acquire information about the shape of the road ahead in the traveling direction of the vehicle 1 by referring to the high-precision map data. At this time, the surrounding environment detection unit 61 acquires information about the radius of curvature of the road. The high-precision map data may be stored in the storage unit 53, or may be stored in an external server connectable via wireless communication means.

[0076] The surrounding environment detection unit 61 may detect measurement objects that can recognize the road shape, such as white lines, curbs, and guardrails on the road ahead, based on the detection data transmitted from the front-viewing cameras 31LF, 31RF and the LiDAR 31S. In this case, the surrounding environment detection unit 61 also calculates the radius of curvature of the road based on the information on the detected measurement objects.

[0077] Next, the output increase prediction unit 63 determines whether or not there is a curve ahead in the traveling direction of the vehicle 1 (step S35). Specifically, the output increase prediction unit 63 determines whether or not a curve with a predetermined radius of curvature or less continues for a predetermined distance or more, based on the road shape information acquired in step S33. The predetermined radius of curvature is set in order to determine the degree of deceleration when passing through a curve, and may be set arbitrarily within a range of, for example, 5 to 30 m. Furthermore, the predetermined distance may be set according to the magnitude of the radius of curvature, so that the larger the radius of curvature, the longer the distance.

[0078] If it is determined that there is no curve ahead (S35 / No), the motor control unit 67 sets the target torques of the front-wheel drive motor 11F and the rear-wheel drive motor 11R in normal mode without limiting the outputs thereof (step S45). Next, the motor control unit 67 controls the drive or regeneration of the front-wheel drive motor 11F and the rear-wheel drive motor 11R based on the set target drive torque or target regenerative torque (step S46). Steps S45 to S46 are executed in accordance with the processing of steps S25 to S26 described in the first embodiment.

[0079] On the other hand, if it is determined that there is a curve ahead (S35 / Yes), the output increase prediction unit 63 estimates the drive torque of the front-wheel drive motor 11F and the rear-wheel drive motor 11R at the exit of the curve (step S37). For example, the output increase prediction unit 63 predicts the driver's brake operation and accelerator operation based on the current vehicle speed of the vehicle 1 detected by the vehicle state sensor 33 and the radius of curvature and distance of the curve, and estimates the drive torque of the vehicle 1 when accelerating at the exit of the curve. The output increase prediction unit 63 also calculates the drive torque (estimated drive torque) when the estimated drive torque is distributed to the front-wheel drive motor 11F and the rear-wheel drive motor 11R in accordance with the normal mode setting.

[0080] Next, the output increase prediction unit 63 determines whether there is a motor whose estimated drive torque is equal to or greater than the rated output torque (step S39). The rated output torques of the front-wheel drive motor 11F and the rear-wheel drive motor 11R are determined from specification data and stored in advance in the storage unit 53. The output increase prediction unit 63 compares the estimated drive torque of each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R with the rated output torque, and determines whether the estimated drive torque of either the front-wheel drive motor 11F or the rear-wheel drive motor 11R is equal to or greater than the rated output torque. It may also be possible to determine whether the estimated drive torque is equal to or greater than the rated output torque only for drive motors whose estimated drive torque is likely to be equal to or greater than the rated output torque based on the drive torque distribution ratio in normal mode.

[0081] If it is determined that there is no motor whose estimated drive torque is equal to or greater than the rated output torque (S39 / No), the motor control unit 67 sets target torques for the front wheel drive motor 11F and the rear wheel drive motor 11R in normal mode (step S45).The motor control unit 67 also controls the drive or regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R based on the set target torques (step S46).

[0082] On the other hand, if it is determined that there is a motor whose estimated drive torque is equal to or greater than the rated output torque (S39 / Yes), the output limiting unit 65 limits the output of the motor predicted to be equal to or greater than the rated output torque (step S41). For example, when the output limiting unit 65 predicts that the estimated drive torque of the rear-wheel drive motor 11R will be equal to or greater than the rated output torque, the output limiting unit 65 sets the upper limit of the regenerative torque of the rear-wheel drive motor 11R when passing through a curve so that it is equal to or less than the rated output torque. Specifically, the output limiting unit 65 reduces the regenerative torque of the rear-wheel drive motor 11R by reducing the proportion of regenerative torque allocated to the rear-wheel drive motor 11R compared to the setting in the normal mode. Alternatively, the output limiting unit 65 may set the rated output torque of the rear-wheel drive motor 11R as the upper limit of the regenerative torque. This prevents the regenerative torque of the rear-wheel drive motor 11R from exceeding the rated output torque during the period until the vehicle 1 reaches the exit of the curve.

[0083] Furthermore, if the output of the rear-wheel drive motor 11R is set to be limited when the temperature of the rear-wheel drive motor 11R or the temperature of the second inverter circuit controlling the rear-wheel drive motor 11R reaches a predetermined limit temperature, the output limiting unit 65 may limit the regenerative torque of the rear-wheel drive motor 11R so that the temperature of the rear-wheel drive motor 11R or the temperature of the second inverter circuit does not reach the predetermined limit temperature when the vehicle 1 accelerates at the exit of a curve. For example, the output limiting unit 65 may predict the amount of heat generated by the rear-wheel drive motor 11R or the second inverter circuit when the vehicle 1 accelerates at the exit of a curve, and limit the regenerative torque of the rear-wheel drive motor 11R to a rated output or less until the vehicle 1 reaches the exit of the curve so that the temperature of the rear-wheel drive motor 11R or the second inverter circuit does not reach the predetermined limit temperature while the vehicle 1 is traveling uphill. Specific processing can be performed in accordance with the processing described in the first embodiment.

[0084] Next, the motor control unit 67 sets the target torque for each drive motor in an output limit mode that limits the output of the drive motors whose estimated drive torque is predicted to be equal to or greater than the rated output torque (step S43). For example, the motor control unit 67 sets the target drive torque or target regenerative torque for the front-wheel drive motor 11F and the rear-wheel drive motor 11R based on the torque distribution ratio for the output limit mode changed in step S41. Then, if the calculated target regenerative torque for the front-wheel drive motor 11F or the rear-wheel drive motor 11R exceeds the rated output torque, the motor control unit 67 distributes the torque exceeding the rated output torque to the other drive motor. Alternatively, the torque may be distributed as a target brake torque for the hydraulic brake system.

[0085] Alternatively, the motor control unit 67 may calculate the target drive torque or target regenerative torque for each of the front-wheel drive motor 11F and the rear-wheel drive motor 11R in normal mode, as in step S45, and then correct the target regenerative torque. For example, if the calculated target regenerative torque for the front-wheel drive motor 11F or the rear-wheel drive motor 11R exceeds the rated output torque, the motor control unit 67 distributes the torque exceeding the rated output torque to the other drive motor.

[0086] Next, similar to step S46, the motor control unit 67 controls the driving or regeneration of the front wheel drive motor 11F and the rear wheel drive motor 11R based on the set target driving torque or target regenerative torque (step S44).

[0087] Next, the output increase prediction unit 63 determines whether or not the vehicle 1 has reached the exit of the curve (step S27). For example, the output increase prediction unit 63 may determine whether or not the vehicle 1 has reached the exit of the curve detected in step S35 based on information about the surrounding environment transmitted from the surrounding environment sensor 31, or may determine whether or not the vehicle 1 has reached the exit of the curve based on information about the position of the vehicle 1 on the high-precision map data.

[0088] If it is not determined that the vehicle 1 has reached the exit of the curve (S47 / No), the motor control unit 67 repeats setting the target torque in the output limit mode (step S43) and controlling the drive or regeneration of the front-wheel drive motor 11F and the rear-wheel drive motor 11R (step S44). On the other hand, if it is determined that the vehicle 1 has reached the exit of the curve (S47 / Yes), or if the drive or regeneration control of the front-wheel drive motor 11F and the rear-wheel drive motor 11R has been executed in step S46, the processing unit 51 determines whether the vehicle's drive system has stopped (step S49). If the drive system has not stopped (S49 / No), the process returns to step S33 and repeats the above-described processing. On the other hand, if the drive system has stopped (S49 / Yes), the processing unit 51 ends the control processing for the front-wheel drive motor 11F and the rear-wheel drive motor 11R.

[0089] FIG. 6 is an explanatory diagram showing the application range of the output limit mode. Suppose that while the vehicle 1 is traveling on a straight road, at time t11, the control device 50 detects a curve ahead in the traveling direction and determines that the estimated drive torque of the rear-wheel drive motor 11R when the vehicle 1 accelerates at the exit of the curve will be equal to or greater than the rated output torque. In this case, the mode for setting the target torque of the front-wheel drive motor 11F and the rear-wheel drive motor 11R is switched from normal mode to output limit mode. The output limit mode continues until time t12 when the vehicle 1 reaches inflection point P of the curve, at which time the mode for setting the target torque of the front-wheel drive motor 11F and the rear-wheel drive motor 11R is switched back from output limit mode to normal mode.

[0090] As a result, from time t11 when the curve is detected to time t12 when the curve's inflection point P is reached, the regenerative torque of the rear-wheel drive motor 11R is limited to or below the rated output, and the temperature rise of the rear-wheel drive motor 11R is suppressed. Therefore, the vehicle 1 can accelerate at the exit of the curve while maintaining a margin of power until the temperature at which the output of the rear-wheel drive motor 11R would decrease. After time t2 when the curve's inflection point P is reached, the vehicle 1 starts accelerating while the temperature of the rear-wheel drive motor 11R is still relatively low, so the time it takes for the rear-wheel drive motor 11R to reach a temperature at which the output of the rear-wheel drive motor 11R would decrease can be delayed, and a decrease in performance of the rear-wheel drive motor 11R can be prevented when accelerating at the exit of the curve.

[0091] <2-3. Effects> As described above, the vehicle control device 50 according to the second embodiment of the present disclosure is applied to a vehicle 1 equipped with a front-wheel drive motor 11F and a rear-wheel drive motor 11R. When a curve is present ahead of the vehicle 1, the control device 50 determines whether the estimated drive torque of the front-wheel drive motor 11F or the rear-wheel drive motor 11R will be equal to or greater than the rated output torque when accelerating at the exit of the curve. Furthermore, if the estimated drive torque of the front-wheel drive motor 11F or the rear-wheel drive motor 11R is equal to or greater than the rated output torque when accelerating at the exit of the curve, the control device 50 limits the output torque of the corresponding drive motor to be equal to or less than the rated output torque until the vehicle 1 reaches the exit of the curve. This suppresses the temperature rise of the rear-wheel drive motor 11R until the vehicle 1 reaches the exit of the curve, thereby lowering the temperature limit of the drive motor when accelerating at the exit of the curve. This reduces the risk of the output of the drive motor decreasing while the vehicle 1 is accelerating at the exit of the curve, resulting in a delay in acceleration.

[0092] In the second embodiment described above, an example of a vehicle 1 in which one front-wheel drive motor 11F is provided on the front wheel side and one rear-wheel drive motor 11R is provided on the rear wheel side has been described, but the vehicle 1 to which the control device 50 according to this embodiment can be applied is not limited to this example. The control device 50 according to this embodiment can also be applied to a vehicle in which drive motors are provided corresponding to the left and right wheels on at least one of the front wheel side or the rear wheel side. In this case, it is desirable to limit the output of the left and right drive motors as a pair to prevent a difference in torque between the left and right wheels.

[0093] <<3. Third Embodiment>> Next, a third embodiment of the present disclosure will be described. In a third embodiment, the control device is applied to a vehicle that has two drive motors connected to left and right wheels on either the front or rear wheels, or both, and that is capable of executing torque vectoring control that assists turning by generating a torque difference between the left and right wheels when the vehicle is turning. The control device according to this embodiment is configured to predict the output of the drive motors when executing torque vectoring control when a curve is present ahead in the vehicle's traveling direction, and when it is predicted that the drive torque of either drive motor will exceed the rated output torque, to limit the drive torque and regenerative torque of the drive motors to below the rated output until the vehicle enters the curve.

[0094] <3-1. Example of vehicle configuration> Fig. 7 is a schematic diagram showing an example of the configuration of a vehicle 1A equipped with a vehicle control device 50 according to this embodiment. The vehicle 1A shown in Fig. 7 is provided with a left rear wheel drive motor 11LR connected to the left rear wheel 3LR and a right rear wheel drive motor 11RR connected to the right rear wheel 3RR, instead of the rear wheel drive motor 11R of the vehicle 1A shown in Fig. 1. The left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR are provided independently so that the drive torque and regenerative torque generated by each are not transmitted to the other side.

[0095] The inverter unit 13 includes a first inverter circuit that controls the driving of the front-wheel drive motor 11F, a second inverter circuit that controls the driving of the left-rear-wheel drive motor 11LR, and a third inverter circuit that controls the driving of the right-rear-wheel drive motor 11RR. The rest of the configuration may be the same as that of the vehicle 1 shown in Fig. 1, and therefore description thereof will be omitted.

[0096] <3-2. Example of control device configuration> The basic configuration of the control device 50 is the same as the configuration of the control device 50 shown in Fig. 2. Below, the vehicle control device 50 according to this embodiment will be described with respect to the differences from the first embodiment.

[0097] In this embodiment, when the vehicle 1A is traveling around a right curve, the motor control unit 67 assists the vehicle 1A in turning right by making the drive torque of the left rear wheel drive motor 11LR greater than the drive torque of the right rear wheel drive motor 11RR. Also, when the vehicle 1A is traveling around a left curve, the motor control unit 67 assists the vehicle 1A in turning left by making the drive torque of the right rear wheel drive motor 11RR greater than the drive torque of the left rear wheel drive motor 11LR.

[0098] Specifically, the motor control unit 67 distributes the target drive torque for the entire vehicle 1A to the front-wheel drive motor 11F on the front wheel side and the right-rear-wheel drive motor 11RR and left-rear-wheel drive motor 11LR on the rear wheel side according to a preset basic ratio. Furthermore, when traveling straight, the motor control unit 67 distributes the drive torque distributed to the rear wheels equally (5:5) to the right-rear-wheel drive motor 11RR and left-rear-wheel drive motor 11LR. On the other hand, when cornering, the motor control unit 67 distributes the drive torque distributed to the rear wheels to the right-rear-wheel drive motor 11RR and left-rear-wheel drive motor 11LR so that the ratio of drive torque of the drive motor provided on the opposite side of the turning direction is larger. The ratio of the distributed drive torque may be increased as the curvature of the curve increases.

[0099] When there is a curve ahead in the traveling direction of the vehicle 1A, the output increase prediction unit 63 predicts an output increase state in which the drive torque of the front-wheel drive motor 11F or the rear-wheel drive motor 11R will exceed the rated output due to torque vectoring control executed when passing through the curve. For example, the output increase prediction unit 63 estimates the drive torque of each of the left rear-wheel drive motor 11LR and the right rear-wheel drive motor 11RR, which is calculated by the drive torque calculation method of the motor control unit 67, based on the radius of curvature and length (continuation distance) of the curve.

[0100] Whether or not there is a curve ahead in the traveling direction of the vehicle 1A may be determined by identifying the position and traveling direction of the vehicle 1A on high-precision map data based on the position data of the vehicle 1A transmitted from the GNSS sensor 35, and by referring to data on the radius of curvature of the road ahead in the traveling direction. Alternatively, whether or not there is a curve ahead in the traveling direction may be determined based on detection data transmitted from the surrounding environment sensor 31. In this case, the surrounding environment detection unit 61 also calculates the radius of curvature of the road based on information on the detected measurement target.

[0101] Furthermore, when the output increase prediction unit 63 predicts that the drive torque of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR will exceed the rated output torque due to torque vectoring control when the vehicle 1A passes through a curve, the output limiting unit 65 sets the drive torque and regenerative torque of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR to be limited to or below the rated output. This suppresses the increase in temperature of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR until the torque vectoring control is started, and makes it possible to lower the temperature peaks of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR when passing through a curve.

[0102] The reason for limiting the output of both the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR, as well as the drive motors whose drive torque exceeds the rated output torque, is to prevent a difference in drive torque between the left and right wheels when the vehicle 1A is traveling straight ahead before entering a curve. The method for limiting the target regenerative torque of the drive motors may be the same as the method for limiting the drive torque and regenerative torque of the rear wheel drive motor 11R to below the rated output in the first embodiment.

[0103] <3-3. Processing operation example> 8 is a flowchart showing the control processing operation of the front-wheel drive motor 11F and the rear-wheel drive motor 11R by the vehicle control device 50 according to this embodiment. The following describes an example in which there is a curve ahead in the traveling direction of the vehicle 1A, and the output of the left rear-wheel drive motor 11LR or the right rear-wheel drive motor 11RR is limited before executing torque vectoring control as the vehicle 1A passes through the curve.

[0104] First, when the drive system of the vehicle 1A is started (step S51), the surrounding environment detection unit 61 of the processing unit 51 acquires information on the shape of the road ahead in the traveling direction of the vehicle 1A (step S53). In this embodiment, similar to step S33 of the processing operation example described in the second embodiment, the surrounding environment detection unit 61 acquires information on the curvature radius of the road ahead in the traveling direction.

[0105] Next, the output increase prediction unit 63 determines whether or not there is a curve ahead in the traveling direction of the vehicle 1A (step S55). Specifically, the output increase prediction unit 63 determines whether or not a curve with a predetermined radius of curvature or less continues for a predetermined distance or more, based on the road shape information acquired in step S53. The predetermined radius of curvature is set to determine whether or not the ratio of the drive torque distribution between the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR in the torque vectoring control executed when traversing a curve is predetermined or more, and may be set arbitrarily within a range of, for example, 5 to 30 meters. Furthermore, the predetermined distance may be set according to the magnitude of the radius of curvature, so that the larger the radius of curvature, the longer the distance.

[0106] If it is not determined that there is a curve ahead (S55 / No), the motor control unit 67 sets target torques for the front wheel drive motor 11F, the left rear wheel drive motor 11LR, and the right rear wheel drive motor 11RR in normal mode without limiting the outputs of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR (step S65). Next, the motor control unit 67 controls the drive or regeneration of the front wheel drive motor 11F, the left rear wheel drive motor 11LR, and the right rear wheel drive motor 11RR based on the set target drive torque or target regenerative torque (step S66). Steps S65 to S66 are executed in accordance with the processing of steps S25 to S26 described in the first embodiment.

[0107] On the other hand, if it is determined that a curve is present ahead (S55 / Yes), the output increase prediction unit 63 estimates the drive torque of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR when torque vectoring control is executed while passing through the curve (step S57). For example, the output increase prediction unit 63 predicts the driver's brake and accelerator operations based on the current vehicle speed of the vehicle 1A detected by the vehicle state sensor 33 and the radius of curvature and distance of the curve, and estimates the drive torque of the vehicle 1A when passing through the curve. The output increase prediction unit 63 also calculates the drive torque when the estimated drive torque is allocated to the front wheel side and the rear wheel side according to the normal mode setting. Furthermore, the output increase prediction unit 63 also calculates the drive torque (estimated drive torque) when the drive torque allocated to the rear wheel side is allocated to the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR according to the torque vectoring allocation ratio.

[0108] Next, the output increase prediction unit 63 determines whether there is a motor whose estimated drive torque is equal to or greater than the rated output torque (step S59). The rated output torques of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR are determined from specification data and are stored in advance in the storage unit 53. The output increase prediction unit 63 compares the estimated drive torque of each of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR with the rated output torque, and determines whether the estimated drive torque of either the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR is equal to or greater than the rated output torque. It may also be possible to determine whether the estimated drive torque is equal to or greater than the rated output torque for only the drive motor with a large allocation ratio between the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR.

[0109] If it is determined that there is no motor whose estimated drive torque is equal to or greater than the rated output torque (S59 / No), the motor control unit 67 sets target torques for the front wheel drive motor 11F, the left rear wheel drive motor 11LR, and the right rear wheel drive motor 11RR in normal mode (step S65).The motor control unit 67 also controls the drive or regeneration of the front wheel drive motor 11F, the left rear wheel drive motor 11LR, and the right rear wheel drive motor 11RR based on the set target torques (step S66).

[0110] On the other hand, if it is determined that there is a motor whose estimated drive torque is equal to or greater than the rated output torque (S59 / Yes), the output limiting unit 65 limits the output of the motor predicted to be equal to or greater than the rated output torque (step S61). For example, if the output limiting unit 65 predicts that the estimated drive torque of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR will be equal to or greater than the rated output torque, the output limiting unit 65 sets the upper limit of the regenerative torque of both the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR so that it is equal to or less than the rated output torque. Specifically, the output limiting unit 65 reduces the regenerative torque of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR by reducing the ratio of drive torque or regenerative torque distributed to the rear wheels compared to the setting in the normal mode. Alternatively, the output limiting unit 65 may set the rated output torque of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR as the upper limit of the regenerative torque.

[0111] The reason for limiting the output of both the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR, as well as the drive motors whose drive torque exceeds the rated output torque, is to prevent a difference in drive torque between the left and right wheels when the vehicle 1A is traveling straight ahead before entering a curve. This ensures that the drive torque and regenerative torque of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR do not exceed the rated output torque during the period before torque vectoring control is started.

[0112] In addition, if the output of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR is set to be limited when the temperature of the left rear wheel drive motor 11LR and the right rear wheel drive motor RR, or the temperature of the second inverter circuit controlling the left rear wheel drive motor 11LR and the third inverter circuit controlling the right rear wheel drive motor 11RR, reaches a predetermined limit temperature, the output limiting unit 65 may limit the drive torque and regenerative torque of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR so that the temperature of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR, or the temperature of the second inverter circuit or the third inverter circuit, does not reach the predetermined limit temperature while torque vectoring control is being executed. For example, the output limiting unit 65 may predict the amount of heat generated by the left rear wheel drive motor 11LR or the second inverter circuit while the torque vectoring control is being executed when the vehicle 1A passes through a right curve, and limit the regenerative torque of the left rear wheel drive motor 11LR to a rated output or less until the torque vectoring control is started so that the temperature of the left rear wheel drive motor 11LR or the second inverter circuit does not reach a predetermined limit temperature while the torque vectoring control is being executed. Specific processing can be executed in accordance with the processing described in the first embodiment.

[0113] Next, the motor control unit 67 sets target torques for the front-wheel drive motor 11F, the left-rear-wheel drive motor 11LR, and the right-rear-wheel drive motor 11RR in an output limit mode that limits the outputs of the left-rear-wheel drive motor 11LR and the right-rear-wheel drive motor 11RR (step S63). For example, the motor control unit 67 sets target drive torques or target regenerative torques for the front-wheel drive motor 11F, the left-rear-wheel drive motor 11LR, and the right-rear-wheel drive motor 11RR based on the torque distribution ratio between the front and rear wheels in the output limit mode changed in step S61. Then, if the calculated target drive torques or target regenerative torques for the left-rear-wheel drive motor 11LR and the right-rear-wheel drive motor 11RR exceed the rated output torque, the motor control unit 67 subtracts the torque exceeding the rated output torque from the torques of the left-rear-wheel drive motor 11LR and the right-rear-wheel drive motor 11RR, respectively, and allocates the subtracted torque to the front-wheel drive motor 11F. Alternatively, the subtracted torque may be allocated as a target brake torque of a hydraulic brake system.

[0114] Alternatively, the motor control unit 67 may calculate the target drive torque or target regenerative torque for each of the front-wheel drive motor 11F, left-rear-wheel drive motor 11LR, and right-rear-wheel drive motor 11RR in normal mode, as in step S65, and then correct the target drive torque or target regenerative torque. For example, if the calculated target drive torque or target regenerative torque for the left-rear-wheel drive motor 11LR or right-rear-wheel drive motor 11RR exceeds the rated output torque, the motor control unit 67 subtracts the torque exceeding the rated output torque from the torque of the left-rear-wheel drive motor 11LR and right-rear-wheel drive motor 11RR, respectively, and allocates the subtracted torque to the front-wheel drive motor 11F.

[0115] Next, similar to step S66, the motor control unit 67 controls the driving or regeneration of the front wheel drive motor 11F, the left rear wheel drive motor 11LR, and the right rear wheel drive motor 11RR based on the set target driving torque or target regenerative torque (step S64).

[0116] Next, the output increase prediction unit 63 determines whether or not the vehicle 1A has reached a position where the execution of torque vectoring control should be started (step S67). The position where the execution of torque vectoring control should be started can be determined as a position where the curvature radius of the road is equal to or smaller than a predetermined threshold. For example, the output increase prediction unit 63 may determine whether or not the vehicle 1A has reached a position where the execution of torque vectoring control should be started based on information about the surrounding environment transmitted from the surrounding environment sensor 31, or may determine whether or not the vehicle 1A has reached the exit of a curve based on information about the position of the vehicle 1A on high-precision map data.

[0117] If it is determined that the vehicle 1A has not reached the position where torque vectoring control is to be started (S67 / No), the motor control unit 67 repeats setting the target torque in the output limit mode (step S63) and controlling the drive or regeneration of the front-wheel drive motor 11F, the left-rear-wheel drive motor 11LR, and the right-rear-wheel drive motor 11RR (step S64). On the other hand, if it is determined that the vehicle 1A has reached the position where torque vectoring control is to be started (S67 / Yes), or if the drive or regeneration control of the front-wheel drive motor 11F, the left-rear-wheel drive motor 11LR, and the right-rear-wheel drive motor 11RR is executed in step S66, the processing unit 51 determines whether the vehicle's drive system has stopped (step S69). If the drive system has not stopped (S69 / No), the process returns to step S63 and repeats the above-described process. On the other hand, if the drive system has stopped (S69 / Yes), the processing unit 51 ends the control process for the front wheel drive motor 11F, the left rear wheel drive motor 11LR, and the right rear wheel drive motor 11RR.

[0118] FIG. 9 is an explanatory diagram showing the application range of the output limit mode. Assume that while vehicle 1A is traveling on a straight road, at time t21, control device 50 detects a curve ahead and determines that the estimated drive torque of left rear wheel drive motor 11LR during torque vectoring control execution as vehicle 1A passes through the curve will be equal to or greater than the rated output torque. In this case, the mode for setting target torques for front wheel drive motor 11F, left rear wheel drive motor 11LR, and right rear wheel drive motor 11RR is switched from normal mode to output limit mode. The output limit mode continues until time t22, when the vehicle reaches a position where torque vectoring control execution starts. At time t22, the mode for setting target torques for front wheel drive motor 11F, left rear wheel drive motor 11LR, and right rear wheel drive motor 11RR is switched back from output limit mode to normal mode.

[0119] As a result, from time t21 when the curve is detected until time t22 when the position where the torque vectoring control execution is started is reached, the drive torque and regenerative torque of the left rear wheel drive motor 11LR and the right rear wheel drive motor 11RR are limited to or below the rated output, thereby suppressing an increase in the temperature of the rear wheel drive motor 11R. Therefore, the execution of torque vectoring control can be started while maintaining a margin of power up to a temperature at which the output of the rear wheel drive motor 11R may decrease. After time t22, torque vectoring control is started when the temperature of the left rear wheel drive motor 11LR is relatively low, which delays the time it takes for the temperature of the left rear wheel drive motor 11LR to reach a temperature at which the output of the left rear wheel drive motor 11LR may decrease, thereby preventing a decrease in performance of the left rear wheel drive motor 11LR while navigating a curve.

[0120] <3-4. Effects> As described above, the vehicle control device 50 according to the third embodiment of the present disclosure is applied to a vehicle 1A equipped with independent left and right rear-wheel drive motors 11LR and 11RR on the rear wheel side. When a curve is present ahead in the traveling direction of the vehicle 1A and torque vectoring control is being executed, the vehicle control device 50 determines whether the estimated drive torque of the left rear-wheel drive motor 11LR or the right rear-wheel drive motor 11RR will be equal to or greater than the rated output torque. Furthermore, if the estimated drive torque of the left rear-wheel drive motor 11LR or the right rear-wheel drive motor 11RR becomes equal to or greater than the rated output torque while torque vectoring control is being executed, the control device 50 limits the output torque of both the left rear-wheel drive motor 11LR and the right rear-wheel drive motor 11RR to be equal to or less than the rated output torque until execution of torque vectoring control is started. This suppresses the temperature rise of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR while the vehicle 1A is passing through a curve, and lowers the temperature point that the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR reaches while passing through a curve. Therefore, it is possible to reduce the risk of the output of the left rear wheel drive motor 11LR or the right rear wheel drive motor 11RR decreasing while the vehicle 1A is passing through a curve, which could result in a decrease in the stability of the vehicle 1A.

[0121] In the third embodiment described above, an example of a vehicle 1A in which one front-wheel drive motor 11F is provided on the front wheel side and independent left and right rear-wheel drive motors 11LR and 11RR are provided on the rear wheel side is described. However, the vehicle 1A to which the control device 50 according to this embodiment can be applied is not limited to this example. The control device 50 according to this embodiment can also be applied to a vehicle in which two independent left and right drive motors are provided on the front wheel side, or a vehicle in which two independent left and right drive motors are provided on each of the front and rear wheels. In this case, in order to prevent a difference in torque between the left and right wheels, it is desirable to limit the output of the left and right drive motors on the front wheel side and the rear wheel side as a pair.

[0122] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0123] It is understood that the following embodiments also fall within the technical scope of the present disclosure. In the vehicle control device according to the third embodiment, the multiple drive motors include a front-wheel drive motor, a left-rear-wheel drive motor that drives the left rear wheels, and a right-rear-wheel drive motor that drives the right rear wheels; the vehicle is configured to be in an output-increasing state and to be able to execute torque vectoring control that assists the vehicle in turning by adjusting the distribution of drive torque to the left and right rear wheels; and when it is determined that torque vectoring control is to be executed ahead in the vehicle's direction of travel, the processor limits the drive torque and regenerative torque of the left-rear-wheel drive motor and the right-rear-wheel drive motor to be equal to or less than the rated output until execution of torque vectoring control begins. In the vehicle control device according to the first to third embodiments described above, the output of the drive motor is limited when the temperature of the drive motor or the temperature of the inverter controlling the drive motor reaches a predetermined limit temperature, and the processor predicts the amount of heat generated by the drive motor or the inverter in an output increase state, and limits the drive torque and regenerative torque of the drive motor to below the rated output until the output increase state is reached, so that the temperature of the drive motor or the inverter does not reach the predetermined limit temperature in the output increase state. A control device for a vehicle having a plurality of drive motors provided corresponding to different wheels, each capable of outputting drive torque for the vehicle and outputting regenerative torque, the vehicle control device comprising: an output increase prediction unit that predicts an output increase state in which the output torque of one of the plurality of drive motors ahead in the direction of travel of the vehicle will exceed its rated output; and an output limiting unit that, when an output increase state is predicted, limits the drive torque and regenerative torque of the drive motor that will exceed the rated output in the output increase state to below the rated output until the output increase state is reached. A recording medium having recorded thereon a computer program that causes a processor to execute processing including predicting an output increase state in which the output torque of one of a plurality of drive motors ahead in the direction of travel of the vehicle will exceed the rated output, and, if an output increase state is predicted, limiting the drive torque and regenerative torque of the drive motor that will exceed the rated output in the output increase state to below the rated output until the output increase state is reached. [Explanation of symbols]

[0124] 1·1A: vehicle, 11F: front wheel drive motor, 11R: rear wheel drive motor, 11LR: left rear wheel drive motor, 11RR: right rear wheel drive motor, 13: inverter unit, 31: ambient environment sensor, 33: vehicle state sensor, 35: GNSS sensor, 50: control device, 51: processing unit, 53: memory unit, 61: ambient environment detection unit, 63: output increase prediction unit, 65: output limiting unit, 67: motor control unit

Claims

1. A control device for a vehicle having a plurality of drive motors provided corresponding to different wheels, each of which is capable of outputting a drive torque for the vehicle and outputting a regenerative torque, one or more processors; and one or more memories communicatively coupled to the one or more processors; the one or more processors: executes a first control that does not restrict the output torque of a first motor of the plurality of drive motors from exceeding a rated output torque; determining whether or not there is a section ahead in the traveling direction of the vehicle in which the estimated output torque of the first motor when the vehicle is caused to travel based on the first control will be equal to or greater than the rated output torque; When it is determined that the section does not exist, the execution of the first control is continued, while When it is determined that the section exists, an upper limit value of the output torque of the first motor is set to be equal to or less than the rated output torque and the upper limit value decreases as the estimated output torque increases, and a second control is executed to limit the drive torque and regenerative torque of the first motor to be equal to or less than the upper limit value until the vehicle reaches the section; After reaching the section, the first control is executed. Vehicle control device.

2. The first motor is provided corresponding to one of a left wheel disposed on the left side of the vehicle and a right wheel disposed on the right side of the vehicle; the plurality of drive motors include a second motor provided corresponding to the other of the left wheel and the right wheel, the one or more processors: In the second control, the drive torque and the regenerative torque of the second motor are further limited to be equal to or less than the upper limit values. The vehicle control device according to claim 1 .

3. The one or more processors: In the second control, the driving torque and the regenerative torque of the second motor are made equal to the driving torque and the regenerative torque of the first motor in a straight traveling state. The vehicle control device according to claim 2.

4. The one or more processors: when it is determined that a curve having a predetermined curvature radius or less continues for a predetermined distance or more ahead in the traveling direction of the vehicle, it is determined whether or not the section exists ahead in the traveling direction of the vehicle. The vehicle control device according to claim 1 .

5. The one or more processors: when it is determined that an uphill road having a gradient exceeding a predetermined gradient exists ahead in the traveling direction of the vehicle, it is determined whether or not the section exists ahead in the traveling direction of the vehicle. The vehicle control device according to claim 1 .

6. The one or more processors: determining whether the section exists ahead in the traveling direction of the vehicle based on an output of a surrounding environment sensor that detects the shape of a road ahead in the traveling direction of the vehicle; The vehicle control device according to any one of claims 1 to 5.

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