Drive control device for electric vehicle

Abstract

A drive control device of an electric vehicle includes: brake devices (30a to 30d) provided respectively at left and right wheels of the vehicle; a front motor (4) and a rear motor (6) that drive and regeneratively brake the wheels of the vehicle; a vehicle motion control section (37) that calculates a brake additional demand amount corresponding to an additional amount of a yaw moment added to the vehicle, in accordance with a running state of the vehicle; a brake ECU (31) that controls the brake devices (30a to 30d) independently of each other in accordance with the brake additional demand amount to control a yaw moment of the vehicle; and a motor torque control section (39) that controls drive torque and regenerative braking torque of the front motor (4) and the rear motor (6), the motor torque control section (39) executing correction to increase the drive torque or decrease the regenerative braking torque in accordance with an increase in braking torque of the brake devices (30a to 30d) in accordance with the brake additional demand amount.

Description

Technical Field

[0001] This invention relates to a drive control device for an electric vehicle capable of independent braking control via the left and right wheels. Background Technology

[0002] In recent years, to prevent vehicle sideslip and improve cornering performance, braking drive devices have been developed that control the driving torque and braking torque of a vehicle with different values ​​for the left and right wheels (driving wheels). Known braking drive devices include vehicle anti-slip devices and active yaw control devices. For example, in the vehicle disclosed in Patent Document 1, each wheel (left, right, front, and rear) is equipped with a drive motor and a braking device, and each drive motor and braking device can be independently controlled. In Patent Document 1, the vehicle's yaw torque is controlled by operating the drive motor or braking device based on the steering angle and the actual yaw rate.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-247276

[0006] The technical problem that the invention aims to solve

[0007] However, in the aforementioned braking drive systems, devices that control the vehicle's yaw moment solely through the braking torque generated by the braking device can be implemented relatively inexpensively and are highly versatile.

[0008] However, by applying braking torque generated by the braking system, the vehicle as a whole will experience a decrease in speed, which may feel unnatural to the driver.

[0009] In addition, the braking system also has the problem of difficulty in controlling the braking torque with high precision due to deviations in the condition of the brake disc. Summary of the Invention

[0010] The present invention was made in view of such a problem, and its object is to provide a drive control device for an electric vehicle that can suppress the discomfort caused by braking in a vehicle in which the yaw moment of the vehicle is controlled by braking the wheels.

[0011] Technical means for solving technical problems

[0012] To achieve the above objectives, the drive control device for an electric vehicle of the present invention includes: a braking device respectively disposed on the left and right wheels of the vehicle; an electric motor that drives and regenerates braking on the wheels of the vehicle; a vehicle motion control unit that calculates an additional yaw moment on the vehicle based on the driving state of the vehicle; a braking device control unit that independently controls the braking device on the left and right sides based on the additional yaw moment calculated by the vehicle motion control unit, thereby controlling the yaw moment of the vehicle; and a motor control unit that controls the driving torque and regenerative braking torque of the electric motor, wherein the motor control unit performs corrective control to increase the driving torque of the electric motor or decrease the regenerative braking torque of the electric motor as the braking torque of the braking device controlled by the braking device control unit increases.

[0013] Therefore, when the yaw moment of the vehicle is controlled by the braking device control unit, the braking device brakes the vehicle. However, as the braking torque increases, the deceleration of the vehicle can be mitigated by increasing the drive torque controlled by the motor control unit or decreasing the regenerative braking torque.

[0014] Preferably, the braking device control unit may perform cornering assist control or cornering spin suppression control based on the vehicle's driving state. The cornering assist control increases the braking torque of the braking device on the inner wheel side of the vehicle to facilitate cornering, while the cornering spin suppression control increases the braking torque of the braking device on the outer wheel side of the vehicle to suppress cornering. When performing the cornering assist control and the cornering spin suppression control, the motor control unit performs different correction controls on the driving torque or the regenerative braking torque, respectively.

[0015] Therefore, by controlling the left and right braking devices through the braking device control unit, it is possible to perform cornering assist control to promote vehicle cornering and cornering spin suppression control to suppress vehicle cornering. Furthermore, by performing different correction controls on driving torque or regenerative braking torque through cornering assist control and cornering spin suppression control, respectively, the driving torque or regenerative braking torque can be appropriately corrected when cornering assist control is executed and when cornering spin suppression control is executed, thereby improving the vehicle's cornering performance or driving stability.

[0016] Preferably, the vehicle may have a front-wheel drive motor that drives the left and right front wheels and a rear-wheel drive motor that drives the left and right rear wheels. As the braking torque of the braking device controlled by the braking device control unit increases, when performing the cornering assist control during acceleration, the motor control unit makes the increase in the driving torque of the rear-wheel drive motor greater than the increase in the driving torque of the front-wheel drive motor. When performing the cornering spin suppression control during acceleration, the motor control unit makes the increase in the driving torque of the front-wheel drive motor greater than the increase in the driving torque of the rear-wheel drive motor.

[0017] Therefore, when performing cornering assist control during acceleration, by increasing the drive torque of the rear-wheel drive motor by more than that of the front-wheel drive motor, speed reduction can be suppressed and cornering performance can be ensured. Furthermore, when performing cornering spin suppression control during acceleration, by increasing the drive torque of the front-wheel drive motor by more than that of the rear-wheel drive motor, speed reduction and cornering spin can be suppressed, thereby ensuring driving stability.

[0018] Preferably, the vehicle may have a front-wheel drive motor that drives the left and right front wheels and a rear-wheel drive motor that drives the left and right rear wheels. As the braking torque of the braking device controlled by the braking device control unit increases, when performing the cornering assist control during deceleration, the motor control unit makes the reduction in regenerative braking torque of the front-wheel drive motor greater than the reduction in regenerative braking torque of the rear-wheel drive motor. When performing the cornering spin suppression control during deceleration, the reduction in regenerative braking torque of the rear-wheel drive motor is greater than the reduction in regenerative braking torque of the front-wheel drive motor.

[0019] Therefore, when performing cornering assist control during deceleration, by making the reduction in regenerative braking torque of the front-wheel drive motor greater than the reduction in regenerative braking torque of the rear-wheel drive motor, speed reduction can be suppressed and cornering performance can be ensured. Furthermore, when performing cornering spin suppression control during deceleration, by making the reduction in drive torque of the rear-wheel drive motor greater than the reduction in drive torque of the front-wheel drive motor, speed reduction and cornering spin can be suppressed, thereby ensuring driving stability.

[0020] Preferably, the motor control unit can independently control the driving torque of the wheels. The vehicle motion control unit calculates and distributes the additional yaw torque applied to the vehicle based on the vehicle's driving state into a yaw torque distribution based on a first additional yaw torque based on the braking device and a second additional yaw torque based on the electric motor. The braking device control unit and the motor control unit control the braking device and the electric motor respectively based on the yaw torque distribution. As the braking torque of the braking device controlled by the braking device control unit increases, the motor control unit, when performing the cornering assist control during acceleration, makes the increase in the driving torque of the wheel on the inner wheel side of the turn greater than the increase in the driving torque of the wheel on the outer wheel side of the turn. When performing the cornering spin suppression control during acceleration, the increase in the driving torque of the wheel on the outer wheel side of the turn is greater than the increase in the driving torque of the wheel on the inner wheel side of the turn.

[0021] Therefore, in vehicles capable of independently controlling the drive torque of the left and right wheels, when cornering assist control is executed during acceleration, each torque is determined in a manner that satisfies the sum of the additional yaw moments calculated by the vehicle motion control unit. For example, when the sum of the additional yaw moments is constant and the braking torque is increased, by making the increase in drive torque of the inner wheel side of the turn greater than the increase in drive torque of the outer wheel side of the turn, speed reduction and excessive cornering can be suppressed, thus ensuring driving stability. Furthermore, when cornering spin suppression control is executed during acceleration, by making the increase in drive torque of the inner wheel side of the turn greater than the increase in drive torque of the outer wheel side of the turn, speed reduction and excessive cornering spin can be suppressed, thereby ensuring cornering performance.

[0022] Preferably, the motor control unit can independently control the driving torque of the wheels. The vehicle motion control unit calculates and distributes the additional yaw torque applied to the vehicle based on the vehicle's driving state into a yaw torque distribution based on a first additional yaw torque of the braking device and a second additional yaw torque of the electric motor. The braking device control unit and the motor control unit control the braking device and the electric motor respectively based on the yaw torque distribution. As the braking torque of the braking device controlled by the braking device control unit increases, when performing the cornering assist control during deceleration, the motor control unit makes the reduction in regenerative braking torque of the inner wheel side of the wheel greater than the reduction in regenerative braking torque of the outer wheel side of the wheel. When performing the cornering spin suppression control during deceleration, the reduction in regenerative braking torque of the outer wheel side of the wheel is greater than the reduction in regenerative braking torque of the inner wheel side of the wheel.

[0023] Therefore, in vehicles capable of independently controlling the drive torque of the left and right wheels, when performing cornering assist control during deceleration, each torque is determined in a manner that satisfies the sum of the additional yaw moments calculated by the vehicle motion control unit. For example, when the total additional yaw moments are constant and the braking torque is increased, by making the reduction in regenerative braking torque of the inner wheel side of the turn greater than the reduction in regenerative braking torque of the outer wheel side of the turn, speed reduction and excessive cornering can be suppressed, thereby ensuring driving stability. Furthermore, when performing cornering spin suppression control during deceleration, by making the reduction in regenerative braking torque of the outer wheel side of the turn greater than the reduction in regenerative braking torque of the inner wheel side of the turn, speed reduction and excessive cornering spin can be suppressed, thereby ensuring cornering performance.

[0024] Effects of the present invention

[0025] The vehicle attitude control device of the present invention brakes the vehicle by means of a braking device when the yaw moment of the vehicle is controlled by the braking device control unit. However, by increasing the driving torque generated by the motor control unit or decreasing the regenerative braking torque along with the increase of the braking torque, the deceleration of the vehicle can be mitigated.

[0026] Therefore, when the yaw moment of the vehicle is controlled by the braking device control unit, it can mitigate the driver's unexpected deceleration and enable driving with less discomfort. Attached Figure Description

[0027] Figure 1 This is a schematic structural diagram of a hybrid vehicle equipped with the drive control device according to the first embodiment of the present invention.

[0028] Figure 2 This is a block diagram showing the schematic structure of the drive control device according to the first embodiment.

[0029] Figure 3 This is a schematic diagram illustrating an example of the driving torque setting when the turning assist control is executed during the left-turn acceleration of a vehicle equipped with the drive control device of the first embodiment.

[0030] Figure 4 This is a schematic diagram illustrating an example of the setting of the drive torque when spin suppression control is executed during the left turn acceleration of a vehicle equipped with the drive control device of the first embodiment.

[0031] Figure 5 This is a schematic diagram illustrating an example of setting the regenerative braking torque when a vehicle equipped with the drive control device of the first embodiment is decelerating to make a left turn and the cornering assist control is executed.

[0032] Figure 6This is a schematic diagram illustrating an example of setting the regenerative braking torque when spin suppression control is executed during the left turn deceleration of a vehicle equipped with the drive control device of the first embodiment.

[0033] Figure 7 This is a schematic diagram illustrating an example of the drive torque setting when the turning assist control is executed during the left-turn acceleration of a vehicle equipped with the drive control device of the second embodiment.

[0034] Figure 8 This is a schematic diagram illustrating an example of the drive torque setting when spin suppression control is executed during the left turn acceleration of a vehicle equipped with the drive control device of the second embodiment.

[0035] Figure 9 This is a schematic diagram illustrating an example of setting the regenerative braking torque when a vehicle equipped with the drive control device of the second embodiment is decelerating to make a left turn and executing the turning assist control.

[0036] Figure 10 This is a schematic diagram illustrating an example of setting the regenerative braking torque when spin suppression control is executed during the left turn deceleration of a vehicle equipped with the drive control device of the second embodiment.

[0037] Figure 11 This is a schematic diagram illustrating an example of setting the drive torque when a vehicle equipped with the drive control device of the third embodiment is accelerating in a straight line.

[0038] Figure 12 This is a schematic diagram illustrating an example of setting the regenerative braking torque when a vehicle equipped with the drive control device of the third embodiment is decelerating in a straight line. Detailed Implementation

[0039] Figure 1 This is a schematic structural diagram of a hybrid vehicle (hereinafter referred to as vehicle 1) having a drive control device according to the first embodiment of the present invention.

[0040] The vehicle 1 (electric vehicle) of the first embodiment of the drive control device of the present invention is a four-wheel drive vehicle that can drive the front wheels 3a and 3b (wheels) by the output of the engine 2 and has an electric front motor 4 (front wheel drive motor, electric motor) for driving the front wheels 3a and 3b and an electric rear motor 6 (rear wheel drive motor, electric motor) for driving the rear wheels 3c and 3d (wheels).

[0041] The engine 2 can drive the drive shaft 8 of the front wheels 3 via the front transmission drive axle 7, and can also drive the electric generator 9 to generate electricity via the front transmission drive axle 7. In addition, the engine 2 and the front wheels 3a and 3b are connected by a clutch 16 disposed in the front transmission drive axle 7.

[0042] The front motor 4 is driven by high-voltage power supplied from the drive battery 11 and electric generator 9 mounted on the vehicle 1 via the front control unit 10, and drives the drive shaft 8 of the front wheels 3a and 3b via the front transmission drive axle 7.

[0043] The rear motor 6 is driven by high-voltage power supplied from the drive battery 11 via the rear control unit 12, and drives the drive shaft 14 of the rear wheels 3c and 3d via the rear transmission drive axle 13.

[0044] The power generated by the electric generator 9 can charge the drive battery 11 via the front control unit 10, and can also supply power to the front motor 4 and the rear motor 6.

[0045] The drive battery 11 is composed of a secondary battery such as a lithium-ion battery, and has a battery module (not shown) formed by combining multiple battery cells. Furthermore, the drive battery 11 includes a charge rate detection unit 11a for detecting the state of charge (SOC) of the drive battery 11.

[0046] The front control unit 10 has the following functions: based on the control signal from the hybrid control unit 20 mounted on the vehicle 1, it controls the drive torque and regenerative braking torque of the front motor 4, and controls the power generation and output of the electric generator 9.

[0047] The rear control unit 12 has the following functions: controlling the drive torque and regenerative braking torque of the rear motor 6 based on the control signal from the hybrid power control unit 20.

[0048] The engine control unit 22 is the control device for the engine 2, and is configured to include input / output devices, storage devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), and timers, etc. Based on control signals (required outputs) from the hybrid power control unit 20, the engine control unit 22 controls the fuel injection quantity and timing, intake air volume, etc., in the engine 2, thereby performing drive control of the engine 2.

[0049] Additionally, vehicle 1 includes a fuel tank 17 for storing fuel supplied to engine 2 and a charger (not shown) for charging drive battery 11 via an external power source.

[0050] The hybrid power control unit 20 is a control device for comprehensive control of the vehicle 1, and is configured to include input / output devices, storage devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), and a timer, etc.

[0051] The front control unit 10, the rear control unit 12, and the engine control unit 22 are connected to the input side of the hybrid power control unit 20, and detection and operation information from these devices is input.

[0052] On the other hand, the front control unit 10, the rear control unit 12, the engine control unit 22, and the clutch 16 of the front transmission drive axle 7 are connected to the output side of the hybrid power control unit 20.

[0053] Furthermore, the hybrid power control unit 20 calculates the vehicle requirements output needed for driving the vehicle 1 based on various detection quantities and various working information such as the throttle operation information of the vehicle 1, and sends control signals to the engine control unit 22, the front control unit 10, and the rear control unit 12 to control the switching of driving modes (EV mode, series mode, parallel mode); the output of the engine 2, the front motor 4 and the rear motor 6; the power generation and output of the electric generator 9; and the disconnection of the clutch 16 in the front transmission drive axle 7.

[0054] In EV mode, engine 2 is stopped, and the front motor 4 and rear motor 6 are driven by the power supplied from the drive battery 11 to make the vehicle move.

[0055] In series mode, the clutch 16 of the front transmission drive axle 7 is disengaged, and the electric generator 9 is activated by the engine 2. The front motor 4 and the rear motor 6 are driven by the electricity generated by the electric generator 9 and the electricity supplied from the drive battery 11, thus enabling the vehicle to move. Additionally, in series mode, the engine 2 is set to a high-efficiency speed, and the remaining output power is supplied to the drive battery 11 to charge it.

[0056] In parallel mode, the clutch 16 connected to the front transmission drive axle 7 mechanically transmits power from the engine 2 to the front wheels 3a and 3b via the front transmission drive axle 7. In addition, the front motor 4 and the rear motor 6 are driven by the electricity generated by the electric generator 9 operated by the engine 2 and the electricity supplied from the drive battery 11.

[0057] The hybrid control unit 20 sets the driving mode to parallel mode, for example, in areas where the engine 2 is more efficient, such as high-speed areas. In addition, in areas other than parallel mode, i.e., low- and medium-speed areas, it switches between EV mode and series mode based on the state of charge (SOC) of the drive battery 11.

[0058] In addition, each wheel 3a to 3d of vehicle 1 is equipped with braking devices 30a, 30b, 30c, and 30d (braking devices) that apply braking torque. Each braking device 30a to 30d is controlled by a brake ECU 31 (brake device control unit), which can independently control the braking torque for each wheel 3a to 3d. The brake ECU 31 is communicatively connected to the hybrid power control unit 20 and performs operational control of each braking device 30a to 30d based on brake pedal operation signals from a brake pedal sensor (not shown).

[0059] Figure 2 This is a block diagram showing the schematic structure of the drive control device 33 according to the first embodiment.

[0060] The drive control device 33 of the first embodiment has a drive control unit 35, which controls the operation of each motor 4, 6, engine 2 and electric generator 9, thereby controlling the driving of the vehicle 1.

[0061] The drive control unit 35 is located in the hybrid power control unit 20 and includes a driver-required torque calculation unit 36, a vehicle motion control unit 37, a brake response characteristic compensation unit 38, a motor torque control unit 39 (motor control unit), and a power generation control unit 40.

[0062] The driver requests the torque calculation unit 36 ​​to input the throttle and brake inputs, and calculates the driver's required torque for vehicle 1. The driver's required torque is the torque required for vehicle 1 to accelerate or decelerate based on the driver's operations such as throttle and brake inputs.

[0063] The vehicle motion control unit 37 inputs parameters related to cornering, such as throttle input, brake input, steering input, vehicle 1 acceleration, and yaw rate, and determines whether cornering assist control and cornering spin suppression control are required. If cornering assist control or cornering spin suppression control is required, the vehicle motion control unit 37 outputs a braking additional demand quantity corresponding to the additional yaw moment required for these controls to the brake ECU 31.

[0064] The brake ECU31 corrects and controls the braking torque of the brake devices 30a to 30d based on the additional braking requirements.

[0065] The cornering assist control is as follows: by making the braking torque of the braking devices 30a to 30d on the steering direction side (inner wheel side of the turn) of vehicle 1 greater than the braking torque of the braking devices 30a to 30d on the opposite steering direction side (outer wheel side of the turn), the yaw moment of vehicle 1 towards the inner wheel side of the turn is increased, thereby promoting the turn of vehicle 1.

[0066] The cornering spin suppression control is as follows: by making the braking torque of the braking devices 30a to 30d on the outer wheel side of the vehicle 1 greater than the braking torque of the braking devices 30a to 30d on the inner wheel side of the vehicle 1, the yaw moment of the vehicle 1 towards the outer wheel side is increased, thereby suppressing the excessive increase of yaw moment during cornering and suppressing the spin of the vehicle 1.

[0067] The brake response characteristic compensation unit 38 receives the additional brake requirement from the vehicle motion control unit 37 and calculates the motor torque correction amount to compensate for the deceleration of the vehicle 1 based on the additional brake requirement.

[0068] The motor torque control unit 39 inputs the sum of the required torque output from the driver's required torque calculation unit 36 ​​and the motor torque correction amount output from the brake response characteristic compensation unit 38, and outputs the required torque of each motor 4 and 6 to the front control unit 10 and the rear control unit 12.

[0069] The power generation control unit 40 inputs the sum of the required torque output from the driver's required torque calculation unit 36 ​​and the motor torque correction amount output from the brake response characteristic compensation unit 38, and outputs a working control signal to the engine control unit 22 and the front control unit 10 as needed, such as when the power supplied from the drive battery 11 to the motors 4 and 6 is insufficient or when the charging rate of the drive battery 11 decreases, so as to generate electricity through the engine 2 and the electric generator 9.

[0070] The following details the motor torque correction amount calculated in the brake response characteristic compensation unit 38.

[0071] Figures 3-6 This is a schematic diagram illustrating an example of setting the drive torque and regenerative braking torque when a vehicle 1 equipped with the drive control device of the first embodiment is making a left turn. Figure 3 This indicates the drive torque when the acceleration-turn assist control is executed. Figure 4 This indicates the driving torque during the execution of the acceleration-rotation suppression control. Figure 5 This indicates the regenerative braking torque during deceleration and cornering assist control. Figure 6 This represents a setting example of the regenerative braking torque during the execution of deceleration and rotation suppression control.

[0072] exist Figures 3-6 And as will be discussed later Figures 7-10In the diagram, the arrows located on the outer sides of wheels 3a-3d indicate the magnitude and direction of the driving torque or regenerative braking torque generated by motors 4 and 6 driving these wheels. Hollow arrows indicate cases where motor torque correction is performed based on the brake response characteristic compensation unit 38, while dashed lines indicate cases where no motor torque correction is performed. Blackened arrows indicate additional braking torque based on the additional braking demand output from the vehicle motion control unit 37. Additionally, a hollow arrow located at the front center of the vehicle indicates a left turn of vehicle 1.

[0073] exist Figures 3-6 In the vehicle 1 of the first embodiment shown, there is a front motor 4 that drives the left and right front wheels 3a and 3b of the vehicle 1 and a rear motor 6 that drives the left and right rear wheels 3c and 3d. The driving torque is the same for the left and right wheels and the rear wheels respectively, but can be set to different values ​​for the left and right wheels.

[0074] like Figure 3 As shown, in the vehicle 1 of the first embodiment, when accelerating to make a left turn, if the vehicle motion control unit 37 performs cornering assist control and the left front brake device 30a on the inner wheel side of the turn is engaged, the braking torque is increased by increasing the drive torque of the front motor 4 and the rear motor 6 based on the braking torque. The increase in drive torque of the four wheels 3a to 3d is then used to compensate for the braking torque imparted by the cornering assist control. This suppresses the speed reduction of the vehicle 1 at moments unexpected by the driver due to cornering assist control. Furthermore, by increasing the drive torque of the rear motor 6 compared to the drive torque of the front motor 4, that is, by increasing the drive torque of the rear wheels 3c and 3d by more than the increase in drive torque of the front wheels 3a and 3b, cornering performance can be improved.

[0075] like Figure 4 As shown, when vehicle 1 accelerates to the left while turning, and the vehicle motion control unit 37 performs cornering spin suppression control and the right front brake device 30b on the outer wheel side of the turn is engaged, the braking torque increases the drive torque of the front motor 4 and the rear motor 6 based on this braking torque. The increase in drive torque of the four wheels 3a to 3d compensates for the braking torque imparted by the cornering spin suppression control. This suppresses the speed reduction of vehicle 1 at moments unexpected by the driver, based on cornering spin suppression control. Furthermore, by increasing the drive torque of the front motor 4 compared to the drive torque of the rear motor 6—that is, by increasing the drive torque of the front wheels 3a and 3b by more than the increase in drive torque of the rear wheels 3c and 3d—straight-line performance is improved, cornering spin is further suppressed, and driving stability is enhanced.

[0076] like Figure 5As shown, when vehicle 1 decelerates for a left turn, with the vehicle motion control unit 37 performing cornering assist control and the left front brake device 30a on the inner wheel side of the turn engaging, the braking torque is compensated by the reduction in the regenerative braking torque of the four wheels 3a to 3d, which in turn reduces the regenerative braking torque of the front motor 4 and the rear motor 6. This reduction in regenerative braking torque can then be used to suppress the speed reduction of vehicle 1 at moments unexpected by the driver, based on cornering assist control. Furthermore, by making the reduction in the regenerative braking torque of the front motor 4 greater than that of the rear motor 6—that is, by making the braking torque of the front wheels 3a and 3b less than that of the rear wheels 3c and 3d—slippage of the front wheels 3a and 3b can be suppressed, ensuring cornering performance.

[0077] like Figure 6 As shown, when vehicle 1 accelerates to the left while turning, and the vehicle motion control unit 37 performs cornering spin suppression control and the right front brake device 30b on the outer wheel side of the turn is engaged, the braking torque is reduced by decreasing the regenerative braking torque of the front motor 4 and the rear motor 6 based on this braking torque. The reduction in the regenerative braking torque of the four wheels 3a to 3d compensates for the braking torque imparted by the cornering spin suppression control. This suppresses the speed reduction of vehicle 1 at moments unexpected by the driver, based on cornering spin suppression control. Furthermore, by reducing the regenerative braking torque of the rear motor 6 compared to the front motor 4—that is, by reducing the regenerative braking torque of the rear wheels 3c and 3d by a greater amount than the reduction in the regenerative braking torque of the front wheels 3a and 3b—straight-line performance is improved, cornering spin is suppressed, and driving stability is enhanced.

[0078] As described above, in this embodiment, when cornering assist control or cornering spin suppression control is executed during cornering, the speed of vehicle 1 is reduced by the operation of braking devices 30a and 30b. However, in this embodiment, the speed reduction of vehicle 1 can be suppressed by correcting the drive torque or regenerative braking torque of motors 4 and 6. Therefore, speed reduction at moments unexpected by the driver based on cornering assist control or cornering spin suppression control can be suppressed. In particular, cornering performance can be improved in cornering assist control, and cornering spin suppression control can further suppress cornering spin and improve driving stability.

[0079] Furthermore, while the vehicle 1 in the first embodiment can be in a parallel configuration, it is preferable to apply the present invention in a driving mode where, as in a series configuration or EV mode, the wheels 3a to 3d are driven solely by motors 4 and 6, and the output of engine 2 does not affect the driving torque of vehicle 1. By configuring the driving mode such as in a series configuration or EV mode, where the output of engine 2 is not mechanically transmitted to the front wheels 3a and 3b, the driving and braking torque of the vehicle as a whole can be controlled with high precision using motors 4 and 6, which are capable of output control with higher precision than engine 2.

[0080] Figures 7-10 This is a schematic diagram illustrating an example of the setting of the drive torque and braking torque of a vehicle 51 equipped with the drive control device of the second embodiment when making a left turn. Figure 7 This indicates a setting example for when acceleration cornering assist control is executed. Figure 8 This represents a setting example for the execution of spin suppression control during acceleration and cornering. Figure 9 This represents a setting example for the execution of deceleration and cornering assist control. Figure 10 This represents a setting example for the execution of deceleration and turn spin suppression control.

[0081] Figures 7-10 The vehicle 51 shown in the second embodiment is a vehicle that has a left rear wheel motor 52c that mainly drives the left rear wheel 3c of the vehicle 51 and a right rear wheel motor 52d that mainly drives the right rear wheel 3d, and has a so-called active yaw control device that can independently control the driving torque and regenerative braking torque of the left and right rear wheels 3c and 3d.

[0082] In this embodiment, the vehicle motion control unit 37 calculates the additional yaw moment and the yaw moment distribution amount applied to the vehicle based on the driving state of the vehicle 1. According to the yaw moment distribution amount, the additional yaw moment is allocated as a first additional yaw moment based on the additional yaw moment of each braking device 30a-30d, and a second additional yaw moment based on the additional yaw moment of each motor 52c, 52d. Furthermore, the vehicle motion control unit 37 outputs the braking additional demand amount of the braking devices 30a-30d corresponding to the first additional yaw moment to the brake ECU 31, and outputs the braking additional demand amount of the motors 52c, 52d corresponding to the second additional yaw moment to the brake response characteristic compensation unit 38.

[0083] The brake ECU 31 performs corrective control on the braking torque of the brake devices 30a to 30d based on the braking additional demand corresponding to the first yaw moment additional amount. The brake response characteristic compensation unit 38 calculates the motor torque correction amount based on the braking additional demand corresponding to the second yaw moment additional amount and performs corrective control on the drive torque of the motors 52c and 52d. Therefore, the sum of the yaw moment additional amount (first yaw moment additional amount) generated by the corrective control of the braking torque of the brake devices 30a to 30d and the yaw moment additional amount (second yaw moment additional amount) generated by the corrective control of the drive torque of the motors 52c and 52d becomes the yaw moment additional amount calculated according to the driving state of the vehicle 1.

[0084] In the cornering assist control of vehicle 51 in this embodiment, the braking torque of the braking devices 30a-30d on the inner wheel side of the turn is greater than the braking torque of the braking devices 30a-30d on the outer wheel side of the turn, and the driving torque of the wheels 3a-3d on the outer wheel side of the turn is set to be greater than that of the inner wheel side by the active yaw control device. Furthermore, in the cornering spin suppression control, the braking torque of the braking devices 30a-30d on the outer wheel side of the turn is set to be greater than the braking torque of the braking devices 30a-30d on the inner wheel side of the turn, and the driving torque of the wheels 3a-3d on the inner wheel side of the turn is set to be greater than that of the outer wheel side by the active yaw control device.

[0085] Furthermore, the vehicle 51 in the second embodiment is a so-called FR vehicle that drives the rear wheels, but it could also be a vehicle capable of driving the front wheels 3a and 3b, as in the first embodiment. In this case, the driving torque and regenerative braking torque of the front wheels 3a and 3b may not need to be modified, or they may be modified as in the first embodiment.

[0086] In vehicle 51, for example, Figure 7As shown, when accelerating to make a left turn, with the vehicle motion control unit 37 performing cornering assist control and the left front brake device 30a on the inner wheel side of the turn engaging, the driving torque of the right rear wheel motor 52d and the left rear wheel motor 52c is increased based on the braking torque. This increase in the driving torque of the left and right rear wheels 3c and 3d compensates for the braking torque imparted by the cornering assist control. This suppresses the speed reduction of the vehicle 51 caused by the cornering assist control at moments unexpected by the driver. Furthermore, the increase in the driving torque of the left rear wheel motor 52c is made greater than the increase in the driving torque of the right rear wheel motor 52d. Specifically, the driving torque of the left and right rear wheels 3c and 3d is controlled so that the sum of the turning torque of the vehicle 51 generated by the braking of the left front brake device 30a on the inner wheel side of the turn and the turning torque of the vehicle 51 generated by the difference in driving torque between the left and right rear wheels matches the required turning torque (yaw moment addition) of the vehicle 51. Therefore, it can suppress the excessive increase in turning torque caused by braking of the left front brake device 30a on the inner wheel side of the turn, and improve the driving stability of the vehicle 51.

[0087] For example, such as Figure 8 As shown, when accelerating to make a left turn, with the vehicle motion control unit 37 performing turn spin suppression control and the right front brake device 30b on the outer wheel side of the turn applying braking, the driving torque of the right rear wheel motor 52d and the left rear wheel motor 52c is increased based on the braking torque. The increase in the driving torque of the left and right rear wheels 3c and 3d compensates for the braking torque imparted by the turn assist control. This suppresses the speed reduction of the vehicle 51 at moments unexpected by the driver, based on turn spin suppression control. Furthermore, by making the increase in the driving torque of the right rear wheel motor 52d greater than the increase in the driving torque of the left rear wheel motor 52c, excessive reduction in turning torque caused by braking of the right front brake device 30b on the outer wheel side of the turn can be suppressed, ensuring the turning performance of the vehicle 51.

[0088] For example, such as Figure 9As shown, when decelerating for a left turn, with the vehicle motion control unit 37 performing cornering assist control and the left front brake device 30a on the inner wheel side of the turn engaging, the regenerative braking torque of the right rear wheel motor 52d and the left rear wheel motor 52c is reduced based on the braking torque. The amount of this reduction in the regenerative braking torque of the right rear wheel motor 52d and the left rear wheel motor 52c compensates for the braking torque imparted by the cornering assist control. This suppresses the speed reduction of the vehicle 51 at moments unexpected by the driver due to cornering assist control. Furthermore, by making the reduction in the regenerative braking torque of the left rear wheel motor 52c greater than the reduction in the regenerative braking torque of the right rear wheel motor 52d, excessive increase in cornering torque caused by braking of the left front brake device 30a on the inner wheel side of the turn can be suppressed, thereby improving the driving stability of the vehicle 51.

[0089] For example, such as Figure 10 As shown, when decelerating for a left turn, with the vehicle motion control unit 37 performing turn spin suppression control and the right front brake device 30b on the outer wheel side applying braking, the regenerative braking torque of the right rear wheel motor 52d and the left rear wheel motor 52c is reduced based on the braking torque. The amount of this reduction in regenerative braking torque of the right rear wheel motor 52d and the left rear wheel motor 52c compensates for the braking torque imparted by the turn spin suppression control. This suppresses the speed reduction of the vehicle 51 at moments unexpected by the driver, based on turn spin suppression control. Furthermore, by making the reduction in the regenerative braking torque of the right rear wheel motor 52d greater than the reduction in the regenerative braking torque of the left rear wheel motor 52c, excessive reduction in turning torque caused by braking of the right front brake device 30b on the outer wheel side can be suppressed, ensuring the turning performance of the vehicle 51.

[0090] Thus, in the vehicle 51 of the second embodiment, by controlling the braking devices 30a to 30d and controlling the driving torque or regenerative braking torque of the left and right rear wheels 3c and 3d, the yaw moment of the vehicle can be controlled, but excessive turning or turning spin suppression when controlling both sides can be suppressed, and appropriate turning can be performed.

[0091] Figure 11 , 12 This is a schematic diagram illustrating an example of setting the drive torque and braking torque when the vehicle 61 equipped with the drive control device of the third embodiment is traveling straight. Figure 11 This indicates the setting example during acceleration. Figure 12 This indicates a setting example for deceleration.

[0092] Figure 11 , 12 The vehicle 61 shown in the third embodiment has a front motor 62 for front-wheel drive.

[0093] In the vehicle 61 of this embodiment, the vehicle motion control unit 37, through the control of the braking devices 30a and 30b of the front wheels 3a and 3b and the front motor 62, can perform the same cornering assist control and cornering spin suppression control as in the first and second embodiments. In particular, yaw moment control, which improves straight-line driving performance, can be performed through cornering spin suppression control. This yaw moment control activates the braking device 30a on the opposite side of the direction of yaw moment generation when a yaw moment is generated during straight-line driving, for example, in the rightward direction, thereby improving straight-line driving performance.

[0094] Furthermore, the vehicle 61 in the third embodiment is a so-called FF vehicle that drives the front wheels 3a and 3b, but the driving torque of the left and right front wheels 3a and 3b is the same. It could also be a vehicle like the first embodiment that can also drive the rear wheels 3c and 3d. In this case, the driving torque and regenerative braking torque of the rear wheels 3c and 3d do not need to be corrected.

[0095] For example, such as Figure 11 As shown, during straight-line acceleration, when yaw moment control is applied to improve straight-line driving performance and the left front brake device 30a is engaged, the increase in the driving torque of the front wheels 3a and 3b due to the braking torque compensates for the braking torque imparted by the yaw moment control by utilizing the increase in the driving torque of the left and right front wheels 3a and 3b. Therefore, during straight-line acceleration, the speed reduction of the vehicle 61 caused by yaw moment control at moments unexpected by the driver can be suppressed.

[0096] like Figure 12 As shown, when decelerating while traveling straight, yaw moment control is applied to improve straight-line driving performance, and the left front brake device 30a is engaged, the regenerative braking torque of the front wheels 3a and 3b is reduced by the braking torque, and the reduction in the regenerative braking torque of the left and right front wheels 3a and 3b is used to compensate for the braking torque imparted by the yaw moment control. Therefore, when decelerating while traveling straight, it is possible to suppress the speed reduction of the vehicle 61 at moments unexpected by the driver due to yaw moment control.

[0097] As described above, in the first to third embodiments, since the yaw moment of vehicles 1, 51, and 61 is controlled by the vehicle motion control unit 37 based on the driving state of vehicles 1, 51, and 61 through the control of the left and right brake devices 30a and 30b, braking of vehicles 1, 51, and 61 sometimes occurs unexpectedly by the driver. However, in the above embodiments, the driving torque or regenerative braking torque of vehicles 1, 51, and 61 is corrected and controlled based on the braking torque supplied by the vehicle motion control unit 37. Specifically, as the braking torque supplied by the vehicle motion control unit 37 increases, the driving torque of each motor 4 and 6 increases when the vehicle accelerates, and the regenerative braking torque generated by each motor 4 and 6 decreases when the vehicle decelerates. As a result, the situation where the speed of vehicle 61 decreases due to braking at unexpected times by the driver caused by the vehicle motion control unit 37 is mitigated, enabling driving with less discomfort.

[0098] Furthermore, as in the first and second embodiments, in vehicles 1 and 51 that can independently control the driving torque of wheels 3a to 3d in the front and rear or left and right directions, by cooperating with the braking of the left and right braking devices 30a and 30b of the vehicle motion control unit 37 to control the driving torque or regenerative braking torque of the front and rear or left and right wheels 3a to 3d of vehicle 1 and 51, vehicle 1 and 51 can perform appropriate turning.

[0099] The vehicle 61 of the third embodiment has the function of braking either of the left and right front wheels 3a and 3b to improve straight-line stability. However, even when braking the front wheels 3a and 3b, the vehicle 61 can suppress unexpected deceleration of the driver's vehicle 61 by increasing the driving torque of the front wheels 3a and 3b or reducing the regenerative braking force.

[0100] The description of the embodiments ends here, but the present invention is not limited to the embodiments described above. For example, in the first to third embodiments described above, the braking devices 30a and 30b of the left and right front wheels 3a and 3b are independently controlled to control the yaw moment of vehicles 1, 51, and 61. However, the present invention can also be applied to vehicles that independently control the braking devices 30c and 30d of the left and right rear wheels 3c and 3d to control the yaw moment.

[0101] In addition, in the second embodiment, there is an active yaw control system that independently controls the driving torque of the left and right rear wheels 3c and 3d, but the present invention can also be applied to vehicles that have an active yaw control system that independently controls the driving torque of the left and right front wheels 3a and 3b.

[0102] In addition, in the first to third embodiments, the driving torque is corrected when accelerating and the regenerative braking torque is corrected when decelerating, but either one can be performed.

[0103] In addition, in the second and third embodiments, the driving torque or regenerative braking torque is corrected by both cornering assist control and cornering spin suppression control, but correction may also be performed only when either control is executed.

[0104] In addition, the present invention can be widely applied to vehicles that can independently control left and right braking devices and vehicles that can be driven by motors.

[0105] Symbol Explanation

[0106] Vehicles 1, 51, and 61

[0107] 3a, 3b Front wheels (wheels)

[0108] 3c, 3d Rear wheels (wheels)

[0109] 4. Front motor (front wheel drive motor, electric motor)

[0110] 6. Rear motor (rear wheel drive motor, electric motor)

[0111] 30a, 30b, 30c, 30d Braking devices (braking systems)

[0112] 31 Brake ECU (Brake Control Unit)

[0113] 33 Drive control device

[0114] 37 Vehicle Motion Control Department

[0115] 39. Motor Torque Control Unit (Motor Control Unit)

Claims

1. A drive control device for an electric vehicle, comprising: Braking devices, which are respectively installed on the left and right wheels of the vehicle; An electric motor that drives and regeneratively brakes the wheels of the vehicle; The vehicle motion control unit calculates the additional yaw moment applied to the vehicle based on the vehicle's driving state. A braking device control unit, which independently controls the braking device from left to right based on the additional yaw moment calculated by the vehicle motion control unit, thereby controlling the yaw moment of the vehicle; and The motor control unit controls the drive torque and regenerative braking torque of the motor. Its features are, The vehicle is equipped with a front-wheel drive motor that drives both the left and right front wheels and a rear-wheel drive motor that drives both the left and right rear wheels, which serve as the electric motors. The braking device control unit performs cornering assist control or cornering spin suppression control based on the vehicle's driving state. Cornering assist control increases the braking torque of the braking device on the inner wheel side of the vehicle during cornering to facilitate cornering, while cornering spin suppression control increases the braking torque of the braking device on the outer wheel side of the vehicle during cornering to suppress cornering. As the braking torque of the braking device controlled by the braking device control unit increases, when performing the cornering assist control during acceleration, the motor control unit makes the increase in the driving torque of the rear-wheel drive motor greater than the increase in the driving torque of the front-wheel drive motor; and when performing the cornering spin suppression control during acceleration, the motor control unit makes the increase in the driving torque of the front-wheel drive motor greater than the increase in the driving torque of the rear-wheel drive motor.

2. A drive control device for an electric vehicle, comprising: Braking devices, which are respectively installed on the left and right wheels of the vehicle; An electric motor that drives and regeneratively brakes the wheels of the vehicle; The vehicle motion control unit calculates the additional yaw moment applied to the vehicle based on the vehicle's driving state. A braking device control unit, which independently controls the braking device from left to right based on the additional yaw moment calculated by the vehicle motion control unit, thereby controlling the yaw moment of the vehicle; and The motor control unit controls the drive torque and regenerative braking torque of the motor. Its features are, The vehicle is equipped with a front-wheel drive motor that drives both the left and right front wheels and a rear-wheel drive motor that drives both the left and right rear wheels, which serve as the electric motors. The braking device control unit performs cornering assist control or cornering spin suppression control based on the vehicle's driving state. Cornering assist control increases the braking torque of the braking device on the inner wheel side of the vehicle during cornering to facilitate cornering, while cornering spin suppression control increases the braking torque of the braking device on the outer wheel side of the vehicle during cornering to suppress cornering. As the braking torque of the braking device controlled by the braking device control unit increases, when performing the cornering assist control during deceleration, the motor control unit makes the reduction in regenerative braking torque of the front wheel drive motor greater than the reduction in regenerative braking torque of the rear wheel drive motor; and when performing the cornering spin suppression control during deceleration, the reduction in regenerative braking torque of the rear wheel drive motor is greater than the reduction in regenerative braking torque of the front wheel drive motor.

3. A drive control device for an electric vehicle, comprising: Braking devices, which are respectively installed on the left and right wheels of the vehicle; An electric motor that drives and regeneratively brakes the wheels of the vehicle; The vehicle motion control unit calculates the additional yaw moment applied to the vehicle based on the vehicle's driving state. A braking device control unit, which independently controls the braking device from left to right based on the additional yaw moment calculated by the vehicle motion control unit, thereby controlling the yaw moment of the vehicle; and The motor control unit controls the drive torque and regenerative braking torque of the motor. Its features are, The motor control unit can independently control the driving torque of either the front or rear wheel. Based on the vehicle's driving state, the vehicle motion control unit calculates and distributes the additional yaw moment applied to the vehicle into a yaw moment distribution amount based on a first yaw moment based on the braking device and a second yaw moment based on the electric motor. The braking device control unit and the motor control unit control the braking device and the motor respectively based on the yaw torque distribution. The braking device control unit performs cornering assist control or cornering spin suppression control. Cornering assist control increases the braking torque of the braking device on the inner wheel side of the vehicle during cornering to facilitate cornering. Cornering spin suppression control increases the braking torque of the braking device on the outer wheel side of the vehicle during cornering to suppress cornering. As the braking torque of the braking device controlled by the braking device control unit increases, when the motor control unit performs the cornering assist control during acceleration, the increase in the driving torque of the wheel on the inner wheel side of the turn is greater than the increase in the driving torque of the wheel on the outer wheel side of the turn. When the cornering spin suppression control is performed during acceleration, the increase in the driving torque of the wheel on the outer wheel side of the turn is greater than the increase in the driving torque of the wheel on the inner wheel side of the turn.

4. A drive control device for an electric vehicle, comprising: Braking devices, which are respectively installed on the left and right wheels of the vehicle; An electric motor that drives and regeneratively brakes the wheels of the vehicle; The vehicle motion control unit calculates the additional yaw moment applied to the vehicle based on the vehicle's driving state. A braking device control unit, which independently controls the braking device from left to right based on the additional yaw moment calculated by the vehicle motion control unit, thereby controlling the yaw moment of the vehicle; and The motor control unit controls the drive torque and regenerative braking torque of the motor. Its features are, The motor control unit can independently control the driving torque of either the front or rear wheel. Based on the vehicle's driving state, the vehicle motion control unit calculates and distributes the additional yaw moment applied to the vehicle into a yaw moment distribution amount based on a first yaw moment based on the braking device and a second yaw moment based on the electric motor. The braking device control unit and the motor control unit control the braking device and the motor respectively based on the yaw torque distribution. The braking device control unit performs cornering assist control or cornering spin suppression control. Cornering assist control increases the braking torque of the braking device on the inner wheel side of the vehicle during cornering to facilitate cornering. Cornering spin suppression control increases the braking torque of the braking device on the outer wheel side of the vehicle during cornering to suppress cornering. As the braking torque of the braking device controlled by the braking device control unit increases, when the motor control unit performs the cornering assist control during deceleration, the reduction in regenerative braking torque of the wheel on the inner wheel side of the turn is greater than the reduction in regenerative braking torque of the wheel on the outer wheel side of the turn. When the cornering spin suppression control is performed during deceleration, the reduction in regenerative braking torque of the wheel on the outer wheel side of the turn is greater than the reduction in regenerative braking torque of the wheel on the inner wheel side of the turn.

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