WO2022153828A1 - Drive system of vehicle - Google Patents

Abstract

A drive system of a vehicle (10) comprises drive motors (21, 22) that drive wheels (11, 12) independently of each other, and steering mechanisms (31, 32) that steer the wheels independently of each other. The drive system of the vehicle comprises: a command value calculation unit (50) that calculates a torque command value for each drive motor, on the basis of an intended traveling state of the vehicle which is intended by a user; abnormality detection units (43, 44) that detect a driving abnormality in which one of the drive motors can output only abnormal torque different from a corresponding torque command value; and steering amount calculation units (46, 50) that, when a driving abnormality is detected, calculates, on the basis of the torque command value corresponding to the drive motor excluding the drive motor having abnormality, the abnormal torque, and the intended traveling state, a steering amount of one of the steering mechanisms as a first steering amount, and a steering amount of the other as a second steering amount with an absolute value smaller than an absolute value of the first steering amount.

Description

Vehicle drive system Cross-reference of related applications

This application is based on Japanese Application No. 2021-003097, which was filed on January 12, 2021, and the contents of the description are incorporated herein by reference.

This disclosure relates to a vehicle drive system.

Conventionally, there are electric vehicles including drive motors that drive the left and right drive wheels on the rear side of the vehicle and steering mechanisms that steer the left and right steering wheels on the front side in the same direction via tie rods (Patent Documents). 1). In the electric vehicle described in Patent Document 1, the steering amount of the steering mechanism is changed so as to compensate for the change in the drive balance of the left and right drive wheels due to the abnormality of the drive motor.

Japanese Patent No. 5936306

By the way, in the electric vehicle (vehicle) described in Patent Document 1, when the steering amount of the steering mechanism is changed so as to compensate for the change in the drive balance of the left and right drive wheels, the change in the steering amount is changed in the vehicle. It has a large effect on the driving condition. Therefore, the change in the steering amount may be excessive or too small, and the vehicle may not be able to travel in the traveling state intended by the driver (user).

The present disclosure has been made to solve the above problems, and the main purpose thereof is intended by the user even when an abnormality occurs in the drive motor of one of the left and right drive wheels. The purpose is to make it easier to drive the vehicle in the running state.

The first means for solving the above problems is a vehicle drive system.
A pair of left and right drive motors that drive the left and right wheels of the vehicle independently of each other,
A pair of left and right steering mechanisms that independently steer the left and right wheels of the vehicle,
A command value calculation unit that calculates each torque command value of each drive motor based on the intended running state of the vehicle intended by the user.
A drive control unit that drives each drive motor based on each torque command value calculated by the command value calculation unit.
An abnormality detection unit that detects a drive abnormality in which one of the pair of left and right drive motors can output only an abnormal torque different from the corresponding torque command value calculated by the command value calculation unit.
When the drive abnormality is not detected by the abnormality detection unit, each steering amount of each steering mechanism is calculated based on the torque command value calculated by the command value calculation unit and the intended running state. When the drive abnormality is detected by the abnormality detection unit, the torque command value, the abnormality torque, and the intended running state corresponding to the drive motor excluding the abnormality motor which is a drive motor capable of outputting only the abnormality torque are obtained. Based on this, the steering amount of one of the pair of left and right steering mechanisms is calculated as the first steering amount, and the steering amount of the other is the second rotation whose absolute value is smaller than the absolute value of the first steering amount. The steering amount calculation unit that calculates the steering amount and
A steering control unit that steers each steering mechanism based on each steering amount calculated by the steering amount calculation unit.
To be equipped.

According to the above configuration, the pair of left and right drive motors drive the left and right wheels of the vehicle independently of each other. The pair of left and right steering mechanisms steer the left and right wheels of the vehicle independently of each other. The left and right wheels of the vehicle driven by the pair of left and right drive motors may be the left and right front wheels of the vehicle, the left and right rear wheels, the left and right front wheels of the vehicle, and the left and right rear wheels. It may be. Further, the left and right wheels of the vehicle steered by the pair of left and right steering mechanisms may be the left and right front wheels of the vehicle, the left and right rear wheels, the left and right front wheels of the vehicle, and the left and right wheels. It may be the rear wheel.

The command value calculation unit calculates each torque command value of each drive motor based on the intended running state, which is the running state of the vehicle intended by the user. The traveling state includes forward straight movement, front left turn, front right turn, rear straight movement, rear left turn, rear right turn, vehicle speed, and the like. The intended driving state can be acquired based on the amount of operation of the steering wheel of the vehicle, the amount of depression of the accelerator pedal (accelerator operation unit) (operation amount), the amount of depression of the brake pedal (brake operation unit) (operation amount), and the like. .. In addition, the intended driving state is the setting of constant-speed running control that causes the vehicle to run at a constant speed, the setting of follow-up running control that causes the vehicle to follow the vehicle in front, and the automatic driving (running) control that causes the vehicle to automatically run the set route. It can be obtained based on the settings of. In the constant speed running control, the following running control, and the automatic driving control, the user may or may not be in the vehicle.

The drive control unit drives each drive motor based on the torque command values calculated by the command value calculation unit. Therefore, each drive motor can be driven so that the traveling state of the vehicle becomes the intended traveling state.

Here, the abnormality detection unit detects a drive abnormality in which one of the pair of left and right drive motors can output only an abnormal torque different from the corresponding torque command value calculated by the command value calculation unit. For example, as a drive abnormality, when the current sensor that detects the current flowing through the drive motor is abnormal, the torque that the drive motor can output is limited to 1/2 of the torque command value, and only torque smaller than the torque command value is output. It may not be possible. Further, as a drive abnormality, the drive motor may output only an abnormal torque larger than the torque command value.

When the drive abnormality is not detected by the abnormality detection unit, the steering amount calculation unit of each steering mechanism is based on the torque command value calculated by the command value calculation unit and the intended running state. Calculate each steering amount. Then, the steering control unit steers each steering mechanism based on each steering amount calculated by the steering amount calculation unit. Therefore, each steering mechanism can be steered so that the traveling state of the vehicle becomes the intended traveling state. The steering amount is 0 when traveling straight, a positive value when steering to one of the left and right, and a negative value when steering to the other.

On the other hand, when the abnormality detection unit detects the drive abnormality, the steering amount calculation unit has the torque command value corresponding to the drive motor excluding the abnormality motor which is a drive motor capable of outputting only the abnormality torque, and the abnormality. Based on the torque and the intended running state, the steering amount of one of the pair of left and right steering mechanisms is calculated as the first steering amount, and the steering amount of the other is calculated from the absolute value of the first steering amount. Is calculated as the second steering amount with a small absolute value. Then, the steering control unit steers each steering mechanism based on each steering amount (first steering amount and second steering amount) calculated by the steering amount calculation unit. Therefore, even when the drive abnormality is detected by the abnormality detection unit, the vehicle is moved based on the torque command value, the abnormality torque, and the intentional running state corresponding to the drive motor excluding the abnormality motor. Each steering mechanism can be steered so as to approach the intended driving state.

Furthermore, the absolute value of the second steering amount is smaller than the absolute value of the first steering amount. Therefore, the influence of the second steering amount on the traveling state of the vehicle is suppressed, and the traveling state of the vehicle can be finely controlled by adjusting the first steering amount. Therefore, even if an abnormality occurs in the drive motor of one of the left and right drive wheels, it is possible to easily drive the vehicle in the traveling state intended by the user.

In the second means, in the steering amount calculation unit, the intended traveling state is straight, the abnormality detection unit detects the drive abnormality, and the abnormality torque is a torque command value corresponding to the abnormality motor. When it is smaller than, the steering amount of the steering mechanism on the same side as the abnormal motor is based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive motor excluding the abnormal motor. The first steering amount is set to the steering amount at which the wheels are directed to the left and right opposite sides of the abnormal motor, and the second steering amount, which is the steering amount of the steering mechanism on the left and right opposite sides of the abnormal motor, is set to 0. To.

When the user intends to drive the vehicle straight (including forward straight and backward straight), and one of the left and right drive motors (abnormal motor) can output an abnormal torque smaller than the torque command value. , The vehicle tries to turn to the same side as the abnormal motor. For example, if the anomalous motor is the drive motor for the right wheel, the vehicle will try to turn to the same right as the anomalous motor.

In this regard, according to the above configuration, in the steering amount calculation unit, the intended traveling state is straight, the drive abnormality is detected by the abnormality detection unit, and the abnormality torque corresponds to the abnormality motor. When it is smaller than the torque command value, the steering mechanism on the same side as the abnormal motor is turned based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state. The first steering amount, which is the steering amount, is set to the steering amount at which the wheels are directed to the left and right opposite sides of the abnormal motor. For example, when the abnormal motor is a drive motor for the right wheel, the first steering amount, which is the same steering amount of the right steering mechanism as the abnormal motor, is directed to the left side opposite to the abnormal motor. Set the steering amount. Therefore, the vehicle that is about to turn to the same side as the abnormal motor can be brought closer to going straight. The abnormal motor and the left-right opposite side are the left-right opposite sides with respect to the traveling direction. If the right drive motor is an abnormal motor, turn the rear part of the wheel to the left.

Further, the steering amount calculation unit sets the second steering amount, which is the steering amount of the steering mechanism on the left and right opposite sides of the abnormal motor, to 0. Therefore, the steering mechanism on the opposite side to the abnormal motor can be controlled in the same manner as when no driving abnormality is detected, and the influence of the second steering amount on the running state of the vehicle is suppressed. By adjusting the first steering amount, it becomes easy to finely control the running state of the vehicle.

In the third means, in the steering amount calculation unit, the intended traveling state is turning, the drive abnormality is detected by the abnormality detection unit, and the abnormal torque is a torque command value corresponding to the abnormal motor. When it is smaller than, the steering amount of the steering mechanism on the left and right opposite sides of the abnormal motor is based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive motor excluding the abnormal motor. The first steering amount is set to the steering amount corresponding to the turning, and the second steering amount, which is the steering amount of the steering mechanism on the same side as the abnormal motor, is set to 0.

When the user intends to turn the vehicle (including front left turn, front right turn, rear left turn, rear right turn), one of the left and right drive motors (abnormal motor) has a torque command value. If only an abnormal torque smaller than that can be output, the vehicle deviates from the turning trajectory (traveling direction) of the vehicle intended by the user.

In this regard, according to the above configuration, in the steering amount calculation unit, the intended traveling state is turning, the drive abnormality is detected by the abnormality detection unit, and the abnormality torque corresponds to the abnormality motor. When it is smaller than the torque command value, the steering mechanism on the left and right sides opposite to the abnormal motor is rotated based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state. The first steering amount, which is the steering amount, is set to the steering amount corresponding to the turning. Therefore, the vehicle that is about to deviate from the turning track of the vehicle intended by the user can be brought closer to the turning track of the vehicle intended by the user.

Further, the steering amount calculation unit sets the second steering amount, which is the steering amount of the steering mechanism on the same side as the abnormal motor, to 0. Therefore, the influence of the second steering amount on the traveling state of the vehicle is suppressed, and the traveling state of the vehicle can be finely controlled by adjusting the first steering amount.

In the fourth means, the command value calculation unit calculates each torque command value of each drive motor based on the intended running state when the drive abnormality is not detected by the abnormality detection unit, and the abnormality is calculated. When the drive abnormality is detected by the detection unit, each of the drive motors excluding the abnormal motor is based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state. Calculate the torque command value. According to such a configuration, the turning trajectory of the vehicle can be brought closer to the turning trajectory intended by the user by controlling the torque of the drive motor.

The fifth means is a vehicle drive system.
A pair of left and right drive motors that drive the left and right wheels of the vehicle independently of each other,
A pair of left and right steering mechanisms that independently steer the left and right wheels of the vehicle,
A command value calculation unit that calculates each torque command value of each drive motor based on the intended running state of the vehicle intended by the user.
A drive control unit that drives each drive motor based on each torque command value calculated by the command value calculation unit.
An abnormality detection unit that detects a drive abnormality in which one of the pair of left and right drive motors can output an abnormal torque smaller than the corresponding torque command value calculated by the command value calculation unit.
When the drive abnormality is not detected by the abnormality detection unit, each steering amount of each steering mechanism is calculated based on the torque command value calculated by the command value calculation unit and the intended running state. The intended running state is turning, the driving abnormality is detected by the abnormality detecting unit, and the intended running state is turning to the same side as the abnormal motor which is a drive motor capable of outputting only the abnormal torque. In this case, a steering amount calculation unit that sets each steering amount of each steering mechanism to 0, and a steering amount calculation unit.
A steering control unit that steers each steering mechanism based on each steering amount calculated by the steering amount calculation unit.
To be equipped.

According to the above configuration, in the steering amount calculation unit, the intended traveling state is turning, the driving abnormality is detected by the abnormality detecting unit, and the intended traveling state is higher than the corresponding torque command value. When turning to the same side as the abnormal motor that can output only a small abnormal torque, the steering amount of each steering mechanism is set to 0. Therefore, each steering mechanism tries to make the vehicle go straight with each wheel facing the front of the vehicle. However, since one of the pair of left and right drive motors can output an abnormal torque smaller than the corresponding torque command value calculated by the command value calculation unit, the vehicle tries to turn to the same side as the abnormal motor. Therefore, it is possible to turn the vehicle in the turning direction intended by the user by utilizing the difference in torque output by the left and right drive motors while suppressing the influence of each steering mechanism on the running state of the vehicle.

In the sixth means, on the premise of the fifth means, the command value calculation unit determines each torque of each drive motor based on the intended running state when the drive abnormality is not detected by the abnormality detection unit. When the command value is calculated and the intended running state is turning, the driving abnormality is detected by the abnormality detecting unit, and the intended running state is turning to the same side as the abnormal motor, the above. Each torque command value of the drive motor excluding the abnormal motor is calculated based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state.

According to the above configuration, each steering amount of each steering mechanism is set to 0 to suppress the influence of each steering mechanism on the running state of the vehicle, and the turning trajectory of the vehicle is also controlled by controlling the torque of the drive motor. It is possible to approach the turning trajectory intended by the user.

The seventh means includes a track calculation unit that calculates a target trajectory on which the vehicle travels based on the intended traveling state, and the command value calculation unit has not detected the drive abnormality by the abnormality detection unit. In this case, each torque command value of each drive motor is calculated so that the track on which the vehicle travels becomes the target track, the intended traveling state is turning, and the abnormality detection unit detects the drive abnormality. Moreover, when the speed of the vehicle is higher than the first speed, the track on which the vehicle travels is determined based on the torque command value, the abnormal torque, and the target track corresponding to the drive motor excluding the abnormal motor. The torque command values of the drive motors other than the abnormal motor are calculated so as to gradually approach the target trajectory from the outside of the target trajectory, and the steering amount calculation unit detects the drive abnormality by the abnormality detection unit. If not, the steering amount of each steering mechanism is calculated so that the track on which the vehicle travels becomes the target trajectory, the intended traveling state is turning, and the driving abnormality is caused by the abnormality detecting unit. When the vehicle is detected and the speed of the vehicle is higher than the first speed, the vehicle travels based on the torque command value, the abnormal torque, and the target trajectory corresponding to the drive motors other than the abnormal motor. Each steering amount of each steering mechanism is calculated so that the trajectory to be driven gradually approaches the target trajectory from the outside of the target trajectory.

According to the above configuration, the track calculation unit calculates the target track on which the vehicle travels based on the intended traveling state. When the drive abnormality is not detected by the abnormality detection unit, the command value calculation unit calculates each torque command value of each drive motor so as to set the track on which the vehicle travels to the target track. The steering amount calculation unit calculates each steering amount of each steering mechanism in order to set the track on which the vehicle travels to the target track when the driving abnormality is not detected by the abnormality detecting unit. Therefore, when a drive abnormality is not detected, the track on which the vehicle travels can be set as the target track.

Here, if a drive abnormality occurs, the track on which the vehicle travels deviates from the target track. When the vehicle is traveling at a speed higher than the first speed and the track of the vehicle is suddenly brought close to the target track, an excessive centrifugal force may act on the driver of the vehicle.

In this regard, the command value calculation unit performs the abnormal motor when the intended traveling state is turning, the driving abnormality is detected by the abnormality detecting unit, and the speed of the vehicle is higher than the first speed. Based on the torque command value, the abnormal torque, and the target track corresponding to the drive motor excluding the above, the abnormal motor so as to gradually bring the track on which the vehicle travels closer to the target track from outside the target track. Calculate each torque command value of the drive motor excluding. Further, the steering amount calculation unit determines the abnormality when the intended traveling state is turning, the driving abnormality is detected by the abnormality detecting unit, and the speed of the vehicle is higher than the first speed. Based on the torque command value corresponding to the drive motor excluding the motor, the abnormal torque, and the target track, each of the above so as to gradually bring the track on which the vehicle travels closer to the target track from outside the target track. Calculate each steering amount of the steering mechanism. Therefore, it is possible to suppress the action of an excessive centrifugal force on the driver of the vehicle, and it is possible to suppress the deterioration of the riding comfort.

When a drive abnormality occurs, the track on which the vehicle travels deviates from the target track. If the speed of the vehicle is lower than the first speed and higher than the second speed, which is lower than the first speed, excessive centrifugal force is applied to the driver of the vehicle even if the track of the vehicle is not gradually brought closer to the target track. Hard to work.

In this regard, in the eighth means, in the command value calculation unit, the intended traveling state is turning, the drive abnormality is detected by the abnormality detection unit, and the speed of the vehicle is higher than the first speed. When it is low and higher than the second speed, which is lower than the first speed, the vehicle travels based on the torque command value, the abnormal torque, and the target track corresponding to the drive motors other than the abnormal motor. Each torque command value of the drive motor excluding the abnormal motor is calculated so that the track on which the vehicle travels approaches the target track while allowing the track to be outside and inside the target track, and the steering is steered. When the intended traveling state is turning, the abnormality detecting unit detects the driving abnormality, and the speed of the vehicle is lower than the first speed and higher than the second speed, the amount calculation unit is used. Based on the torque command value, the abnormal torque, and the target track corresponding to the drive motor excluding the abnormal motor, the track on which the vehicle travels is allowed to be outside and inside the target track. Each steering amount of each steering mechanism is calculated so that the track on which the vehicle travels approaches the target trajectory. Therefore, when it is difficult for an excessive centrifugal force to act on the driver of the vehicle, the track on which the vehicle travels can be quickly brought closer to the target track.

When a drive abnormality occurs, the track on which the vehicle travels deviates from the target track. When the speed of the vehicle is lower than the second speed, the centrifugal force acting on the driver of the vehicle is small, so that it is not necessary to control the speed of the vehicle.

In this regard, in the ninth means, in the steering amount calculation unit, the intended traveling state is turning, the driving abnormality is detected by the abnormality detecting unit, and the speed of the vehicle is higher than the second speed. When the speed is low, each of the rudders is steered so as to bring the track on which the vehicle travels closer to the target track based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the target track. Calculate each steering amount of the mechanism. Therefore, when it is less necessary to control the speed of the vehicle, it is not necessary to calculate each torque command value of the drive motor excluding the abnormal motor based on the target trajectory, and the control load of the drive system can be reduced. ..

In the tenth means, limit detection is performed to detect a limited state in which an abnormality related to one of the pair of left and right drive motors occurs and the torque output by the one drive motor is limited so as not to exceed the upper limit value. The abnormality detection unit includes a unit, and the torque command value corresponding to the drive motor in which the restriction state is detected by the restriction detection unit and the torque is restricted so as not to exceed the upper limit value is the upper limit value. When it is larger than, the drive abnormality is detected, and the steering amount calculation unit detects the restriction state by the restriction detection unit, and the drive motor is restricted so that the torque does not exceed the upper limit value. When the corresponding torque command value is smaller than the upper limit value, each steering amount of each steering mechanism is calculated based on each torque command value calculated by the command value calculation unit and the intended traveling state. ..

According to the above configuration, the limit detection unit is in a limited state in which an abnormality related to one of the pair of left and right drive motors occurs and the torque output by the one drive motor is limited so as not to exceed the upper limit value. Is detected. In the limited state, when the torque command value is larger than the upper limit value, the output torque is limited so as not to exceed the upper limit value. Therefore, in the abnormality detection unit, the torque command value corresponding to the drive motor in which the restriction state is detected by the restriction detection unit and the torque is restricted so as not to exceed the upper limit value is higher than the upper limit value. If it is large, the drive abnormality is detected. Then, when the drive abnormality is detected by the abnormality detection unit, the steering amount calculation unit determines the torque command value, the abnormality torque, and the abnormality torque corresponding to the drive motors other than the abnormality motor, as described above. Based on the intended running state, the steering amount of one of the pair of left and right steering mechanisms is calculated as the first steering amount, and the steering amount of the other is calculated as an absolute value rather than the absolute value of the first steering amount. Calculated as a small second steering amount.

On the other hand, even in the limited state, if the torque command value is smaller than the upper limit value, the torque of the torque command value should be output even if the drive motor is restricted so that the torque does not exceed the upper limit value. Can be done. In this regard, in the steering amount calculation unit, the torque command value corresponding to the drive motor in which the restriction state is detected by the restriction detection unit and the torque is restricted so as not to exceed the upper limit value is the upper limit. When it is smaller than the value, each steering amount of each steering mechanism is calculated based on each torque command value calculated by the command value calculation unit and the intended traveling state. Therefore, the vehicle can be driven in the intended traveling state.

It is conceivable that both the left and right pair of drive motors can output only a common predetermined torque smaller than each torque command value. In this case, since the torques output by the pair of left and right drive motors do not differ significantly, it is less necessary to calculate the steering amounts of the pair of left and right steering mechanisms as different steering amounts.

In this regard, in the eleventh means, the abnormality detection unit can output only a common predetermined torque smaller than the corresponding torque command value calculated by the command value calculation unit for both the left and right drive motors. When a drive abnormality is detected, the steering amount calculation unit detects both drive abnormalities by the abnormality detection unit, and when the abnormality detection unit detects both drive abnormalities, the steering amount of each steering mechanism is based on the predetermined torque and the intended running state. Is calculated. Therefore, it is possible to reduce the processing load for the steering amount calculation unit to calculate each steering amount.

The above objectives and other objectives, features and advantages of the present disclosure will be clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a block diagram of a vehicle drive system. FIG. 2 is a schematic view showing the operation of the steering mechanism in a front-wheel drive vehicle under normal conditions. FIG. 3 is a schematic view showing the operation of the steering mechanism at the time of abnormality. FIG. 4 is a flowchart showing a procedure for controlling the drive system in the event of an abnormality. FIG. 5 is a table showing the torque upper limit value at the time of abnormality. FIG. 6 is a graph showing the relationship between the amount of steering wheel operation, the vehicle speed, and the target turning radius. FIG. 7 is a schematic view showing an example of changing the operation of the steering mechanism at the time of abnormality. FIG. 8 is a schematic view showing another example of changing the operation of the steering mechanism at the time of abnormality. FIG. 9 is a schematic diagram showing an example of changing the control of the drive system in the event of an abnormality. FIG. 10 is a schematic diagram showing another example of changing the control of the drive system in the event of an abnormality. FIG. 11 is a schematic view showing the operation of the steering mechanism at the time of abnormality in reverse movement. FIG. 12 is a schematic view showing an example of changing the operation of the steering mechanism at the time of abnormality in reverse movement. FIG. 13 is a schematic view showing another example of modification of the operation of the steering mechanism at the time of abnormality in reverse movement. FIG. 14 is a schematic view showing the operation of the steering mechanism in a normal state in a rear-wheel drive vehicle. FIG. 15 is a schematic view showing the operation of the steering mechanism at the time of abnormality. FIG. 16 is a schematic view showing an example of changing the operation of the steering mechanism at the time of abnormality. FIG. 17 is a schematic view showing another example of changing the operation of the steering mechanism at the time of abnormality. FIG. 18 is a schematic view showing the operation of the steering mechanism at the time of abnormality in a four-wheel drive vehicle. FIG. 19 is a schematic view showing an example of changing the operation of the steering mechanism at the time of abnormality. FIG. 20 is a schematic view showing another example of modification of the operation of the steering mechanism at the time of abnormality. FIG. 21 is a schematic view showing another example of changing the operation of the steering mechanism at the time of abnormality. FIG. 22 is a schematic view showing another example of changing the operation of the steering mechanism at the time of abnormality. FIG. 23 is a schematic view showing another example of modification of the operation of the steering mechanism at the time of abnormality.

Hereinafter, an embodiment embodied in the drive system of an electric vehicle will be described with reference to the drawings.

As shown in FIG. 1, the electric vehicle 10 (vehicle) has wheels 11 to 14, drive units 21 and 22, steering units 31, 32, drive control unit 41, torque determination unit 42, abnormality detection unit 43, and abnormality determination. It includes a steering unit 44, a steering control unit 45, a steering amount determination unit 46, a vehicle control unit 50, a steering wheel operation amount detection unit 51, an accelerator operation amount detection unit 52, a vehicle speed detection unit 53, and the like.

The left wheel 11 and the right wheel 12 on the front side are driving wheels for driving the electric vehicle 10. The wheels 11 and 12 are driven by the drive units 21 and 22. The wheels 11 and 12 also serve as steering wheels that change the traveling direction of the electric vehicle 10 by changing the steering angle by the steering units 31 and 32 based on the steering wheel operation. The left and right wheels 13 and 14 on the rear side are driven wheels that are driven as the electric vehicle 10 travels. The wheels 11 to 14 are braked by a braking mechanism (not shown). Each drive unit 21 and 22 may have a function of a braking mechanism for braking each of the wheels 11 and 12.

Each drive unit 21 and 22 is equipped with a drive MG (Motor Generator), an INV (Inverter), a current sensor, a temperature sensor, a rotation angle sensor, and the like. The drive MG (drive motor) is a three-phase AC motor generator (AC motor). Each drive MG has a function of driving the wheels 11 and 12 based on the electric power supplied from each INV and a function of generating electricity based on the rotation of the wheels 11 and 12. Each drive MG (each drive unit 21 and 22) drives the wheels 11 and 12 independently of each other. Each INV converts the DC power supplied from the battery (not shown) into AC power and supplies it to each drive MG. Each INV is, for example, a circuit in which six switching elements are connected by a three-phase bridge. Further, each INV converts the AC power supplied by the power generation of each drive MG into DC power and supplies the AC power to the battery. The drive state of each INV (each drive unit 21 and 22) is controlled by the drive control unit 41. Here, three-phase alternating current is described as an example, but the number of phases is not limited to three, and may be six phases, nine phases, or the like.

The steering units 31 and 32 steer the wheels 11 and 12 independently of each other. Each of the steering units 31 and 32 (steering mechanism) includes a steering MG, an INV, and the like. Each steering MG (each steering motor) generates a steering force which is a force for changing the steering angles (directions) of the wheels 11 and 12. Each steering MG is connected to a battery via each INV. Each INV converts DC power from the battery into AC power and supplies power to each steering motor. The drive state of each INV (each steering unit 31, 32) is controlled by the steering control unit 45.

The abnormality detection unit 43 detects an abnormality in each drive unit 21 or 22. Specifically, the current of each drive MG detected by each current sensor, the coil temperature of each drive MG detected by each temperature sensor (hereinafter referred to as “coil temperature”), and each detected by each rotation angle sensor. Based on the rotation angle of the drive MG, the abnormality of each current sensor, each temperature sensor, and each rotation angle sensor is detected. The abnormality detection unit 43 may detect an abnormality in each drive MG, each INV, etc. of each drive unit 21 and 22.

The abnormality determination unit 44 identifies (determines) an abnormality wheel, which is a wheel corresponding to the drive unit in which the abnormality has occurred, based on the abnormality detected by the abnormality detection unit 43. Then, the abnormality determination unit 44 (abnormality detection unit) can output only an abnormal torque different from the corresponding torque command value calculated by the vehicle control unit 50 by one of the drive MGs of the pair of left and right drive units 21 and 22. Is detected. Hereinafter, the drive MG capable of outputting only abnormal torque is referred to as an abnormal drive MG (abnormal motor). Specifically, the abnormality determination unit 44 (limit detection unit) prevents an abnormality related to one of the drive MGs of the pair of left and right drive units 21 and 22 from occurring, and the torque output by one drive MG does not exceed the upper limit value. Detects restricted states that are restricted to. The abnormality determination unit 44 detects a drive abnormality when the limited state is detected and the torque command value corresponding to the abnormal drive MG whose torque is restricted so as not to exceed the upper limit value is larger than the upper limit value. Further, the abnormality determination unit 44 determines a communication abnormality between the vehicle control unit 50 and the torque determination unit 42. The abnormality determination unit 44 transmits the abnormality determination result to the vehicle control unit 50. The abnormality detection unit 43 and the abnormality determination unit 44 constitute an abnormality detection unit.

The vehicle control unit 50 (upper control unit) controls the entire electric vehicle 10. The vehicle control unit 50 is a microcomputer provided with, for example, a CPU, RAM, ROM, an input / output interface, and the like. Detection values of the steering wheel operation amount detection unit 51, the accelerator operation amount detection unit 52, the vehicle speed detection unit 53, and the like are input to the vehicle control unit 50.

The steering wheel operation amount detection unit 51 detects the steering angle (operation amount) of the steering wheel (steering unit). The accelerator operation amount detection unit 52 detects the amount of depression (operation amount) of the accelerator pedal (accelerator operation unit). The vehicle speed detection unit 53 detects the speed (vehicle speed) of the electric vehicle 10.

The vehicle control unit 50 executes various controls of the electric vehicle 10 based on the detected values of the detection units 51 to 53 and the like. The vehicle control unit 50 (command value calculation unit) has a torque command value (basic torque value) of each drive unit 21 and 22 and a torque command value (basic torque value) of each drive unit 21 and 22 based on the detection values of the detection units 51 to 53 and the determination result of the abnormality determination unit 44. The torque distribution, the steering amount command value (basic steering amount) and the steering amount distribution of each of the steering units 31 and 32 are calculated. That is, each torque command value of each drive MG of each drive unit 21 and 22 is calculated based on the intentional running state which is the running state of the electric vehicle 10 intended by the driver (user). For example, when the electric vehicle 10 goes straight, the torque distribution of the drive units 21 and 22 is equalized, and when the electric vehicle 10 turns to the left, the torque distribution of the drive unit 22 is made larger than the torque distribution of the drive unit 21. For example, when the drive units 21 and 22 are normal, the steering amount distribution of the steering units 31 and 32 is equalized, and when one of the drive units 21 and 22 is abnormal, the steering unit is described later. The steering amount distribution of 31 and 32 is changed from equal.

The torque determination unit 42 is, for example, a microcomputer provided with a CPU, RAM, ROM, an input / output interface, and the like. The torque determination unit 42 determines the final torque command value based on the torque command value, the torque distribution, and the upper limit value.

Specifically, the torque determination unit 42 has an upper limit value of the torque that can be generated by each drive MG of each drive unit 21 and 22 based on the coil temperature detected by each temperature sensor of each drive unit 21 and 22 (hereinafter, Limit the "torque upper limit"). Specifically, when the coil temperature is less than T1, the torque determination unit 42 sets the torque upper limit value to the upper limit value Tr1. When the coil temperature is T1 or higher (when the abnormality determination unit 44 detects the drive abnormality), the torque determination unit 42 reduces the torque upper limit value as the coil temperature increases. Then, when the coil temperature exceeds T2 (> T1) (when the abnormality determination unit 44 detects the drive abnormality), the torque determination unit 42 sets the torque upper limit value to 0. The torque determination unit 42 limits the torque command value to the torque upper limit value or less (upper limit guard), determines the final torque command value, and transmits the determined final torque command value to the drive control unit 41. The torque value here is assumed to be an absolute value.

In addition, if a predetermined abnormality occurs in the current sensor, the current may be erroneously detected and the torque generated by the drive MG may change suddenly. Predetermined abnormalities include, for example, disconnection of wiring related to the current sensor, short circuit of the current sensor, gain abnormality of the current sensor, and the like. Therefore, when the torque determination unit 42 detects a predetermined abnormality of the current sensor (when the abnormality determination unit 44 detects the drive abnormality), the torque determination unit 42 torques in a predetermined period prior to the detection of the predetermined abnormality. The final torque command value is determined by reducing the command value by a predetermined degree. The final torque command value is, for example, a value obtained by halving the torque command value. It should be noted that a value obtained by reducing the torque command value to 1/3 or a value obtained by subtracting a predetermined value from the torque command value can also be adopted.

Further, if an abnormality occurs in the rotation angle sensor, the drive MG cannot be appropriately controlled according to the rotation angle, and the torque generated by the drive MG may change suddenly. Therefore, when the torque determination unit 42 detects an abnormality in the rotation angle sensor (when the abnormality determination unit 44 detects the drive abnormality), the torque command unit 42 gives a torque command in a predetermined period before the abnormality is detected. The final torque command value is determined by reducing the value by a predetermined degree. The final torque command value is, for example, a value obtained by halving the torque command value. The torque command value can also be set to 0.

The drive control unit 41 controls the drive and power generation of each drive MG of each drive unit 21 and 22 by controlling the drive state of each INV of each drive unit 21 and 22 based on the final torque command value. In each drive unit 21 and 22, each drive control unit 41 is based on the current of each phase of each drive MG detected by each current sensor and the rotation angle of each drive MG detected by each rotation angle sensor. The drive state of each INV is controlled so that the torque generated by the drive MG becomes the final torque command value. That is, each drive MG of each drive unit 21 and 22 is driven based on each torque command value calculated by the vehicle control unit 50 and each final torque command value determined by the torque determination unit 42.

The steering amount determination unit 46 is, for example, a microcomputer provided with a CPU, RAM, ROM, an input / output interface, and the like.

When the drive abnormality is not detected by the abnormality determination unit 44, the steering amount determination unit 46 determines (calculates) the final steering amount command value based on the steering amount command value and the steering amount distribution. That is, when the driving abnormality is not detected by the abnormality determination unit 44, the steering amount determining unit 46 determines each steering unit 31 based on each torque command value calculated by the vehicle control unit 50 and the intended traveling state. , 32 each final steering amount command value (each steering amount) is determined. Specifically, as shown in FIG. 2, the steering amount determining unit 46 sets the final steering amount command values of the steering units 31 and 32, that is, the steering amounts of the wheels 11 and 12, to 0 when traveling straight ahead, for example. decide. The steering amount determining unit 46 determines, for example, the final steering amount command values of the steering units 31 and 32 to a common positive value when turning forward and left. The steering amount determining unit 46 determines, for example, the final steering amount command values of the steering units 31 and 32 to a common negative value when turning forward and to the right. The thin arrows indicate the torque acting on each wheel, the driving wheels are shown in black, and the driven wheels are shown in white (the same applies hereinafter). The steering amount determination unit 46 and the vehicle control unit 50 constitute a steering amount calculation unit.

Here, when the driver intends to make the electric vehicle 10 go straight forward (straight ahead), for example, the drive MG (abnormal drive MG) corresponding to the wheel 12 can output only an abnormal torque smaller than the torque command value. When it disappears, the electric vehicle 10 tries to turn to the same side as the abnormal drive MG. For example, when the abnormal drive MG is a drive MG corresponding to the wheel 12 on the right side, the electric vehicle 10 tries to turn to the same right side as the abnormal drive MG.

Therefore, as shown in FIG. 3, when the abnormality determining unit 44 detects the driving abnormality, the steering amount determining unit 46 determines the torque command value corresponding to the driving MG excluding the abnormal driving MG, the abnormal torque, and the above-mentioned abnormal torque. And, based on the intended running state, one of the pair of left and right steering units 31 and 32 is calculated as the first steering amount, and the other steering amount is larger than the absolute value of the first steering amount. It is calculated as the second steering amount with a small absolute value. The length of the thin arrow indicates the magnitude of the torque acting on each wheel, and the abnormal wheel is shaded (the same applies hereinafter).

Specifically, when the intentional running state is straight, the abnormality determination unit 44 detects a drive abnormality, and the abnormality torque is smaller than the torque command value corresponding to the abnormality drive MG, the steering amount determination unit 46 has a steering amount determination unit 46. Based on the torque command value, abnormal torque, and intended driving state corresponding to the drive MG excluding the abnormal drive MG, the first steering amount, which is the steering amount of the steering unit on the same side as the abnormal drive MG, is abnormally driven. Set the steering amount so that the wheels are directed to the opposite side of the MG. For example, when the abnormal drive MG is a drive MG corresponding to the right wheel 12, the first steering amount, which is the same steering amount of the right steering unit 32 as the abnormal drive MG, is opposite to that of the abnormal drive MG. Set the steering amount to positive so that the wheel 12 is directed to the left side. As a result, the electric vehicle 10 that is about to turn to the same side as the abnormal drive MG is brought closer to straight ahead. That is, the traveling state of the electric vehicle 10 is brought closer to the intended traveling state. The abnormally driven MG and the left and right opposite sides are opposite to each other with respect to the traveling direction. For example, when the driving MG is straight ahead and the right driving MG is the abnormal driving MG, the front portion of the wheel 12 is turned to the left. Further, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 31 on the opposite side to the abnormal drive MG, to 0. That is, the steering unit 31 on the opposite side to the abnormal drive MG is controlled in the same manner as when no drive abnormality is detected.

Further, when the driver intends to turn the electric vehicle 10 (front left turn, front right turn), one of the left and right drive MGs (abnormal drive MG) has an abnormal torque smaller than the torque command value. If only the output is possible, the electric vehicle 10 deviates from the turning trajectory (traveling direction) of the electric vehicle 10 intended by the driver.

Therefore, as shown in FIG. 3, in the steering amount determination unit 46, the intended traveling state is turning, the drive abnormality is detected by the abnormality determination unit 44, and the abnormal torque is the torque command value corresponding to the abnormal drive MG. When it is smaller than, it is the steering amount of the steering unit on the left and right opposite sides of the abnormal drive MG based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG. Set the steering amount to the steering amount corresponding to turning. That is, the traveling state of the electric vehicle 10 is brought closer to the intended traveling state. For example, when the abnormal drive MG is the drive MG corresponding to the right wheel 12 when turning forward and left, the first steering amount, which is the steering amount of the left steering unit 31 opposite to the abnormal drive MG, is turned left. Set the amount of steering to be positive corresponding to the number of times. When the abnormal drive MG is the drive MG corresponding to the right wheel 12 when turning forward and right, the first steering amount, which is the steering amount of the left steering unit 31 opposite to the abnormal drive MG, is set. Set the amount of steering to a negative value corresponding to a right turn. Further, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 32 on the same side as the abnormal drive MG, to 0 (the absolute value is smaller than the absolute value of the first steering amount). The amount of steering). As a result, the traveling state of the electric vehicle 10 is finely controlled by adjusting the first steering amount while suppressing the influence of the second steering amount on the traveling state of the electric vehicle 10.

Further, even in the limited state in which the torque output by one of the drive MGs is restricted so as not to exceed the upper limit value, if the torque command value is smaller than the upper limit value, the abnormal drive MG is the torque of the torque command value. Can be output. Therefore, in the steering amount determination unit 46, the torque command value corresponding to the abnormal drive MG in which the restricted state is detected by the abnormality determination unit 44 and the torque is restricted so as not to exceed the upper limit value is smaller than the upper limit value. In this case, the final steering amount command values of the steering units 31 and 32 are calculated based on the torque command values calculated by the vehicle control unit 50 and the intended traveling state. As a result, the electric vehicle 10 is driven in the intended traveling state.

Then, the steering control unit 45 controls the driving state of each INV of each steering unit 31 and 32 so that the steering amount of each steering unit 31 and 32 becomes each final steering amount command value. That is, the steering control unit 45 steers the steering units 31 and 32 based on the final steering amount command value determined (calculated) by the steering amount determining unit 46.

FIG. 4 is a flowchart showing a procedure for controlling the drive system in the event of an abnormality.

First, the abnormality detection unit 43 determines whether or not an abnormality in each drive unit 21 or 22, specifically, an abnormality in each current sensor, each temperature sensor, and each rotation angle sensor of each drive unit 21, 22 is detected ( S10). In this determination, if it is determined that an abnormality in each of the drive units 21 and 22 has not been detected (S10: NO), the determination in S10 is executed again.

On the other hand, when it is determined in the determination of S10 that an abnormality of each drive unit 21 or 22 is detected (S10: YES), the abnormality determination unit 44 identifies the abnormality wheel (S11).

Subsequently, the torque determination unit 42 sets the upper limit value of the torque of the abnormal drive MG corresponding to the abnormal wheel (S12). As shown in FIG. 5, when an abnormality occurs in the current sensor, the upper limit value of the torque is set to 1/2 of the torque command value, and when an abnormality occurs in the rotation angle sensor, the upper limit value of the torque is set to the torque command value. If a communication error occurs, set the upper limit of torque to the immediately preceding torque command value.

Subsequently, the steering wheel operation amount detection unit 51 detects the steering angle (operation amount) of the steering wheel (S13). The accelerator operation amount detection unit 52 detects the depression amount (operation amount) of the accelerator pedal (accelerator operation unit) (S14). The vehicle speed detection unit 53 detects the speed (vehicle speed) of the electric vehicle 10 (S15).

Subsequently, the vehicle control unit 50 (track calculation unit) calculates the target track of the electric vehicle 10 (S16). Specifically, as shown in FIG. 6, the target turning radius (target trajectory) is calculated based on the graph showing the relationship between the detected steering wheel operation amount, the detected vehicle speed, and the target turning radius. The graph of FIG. 6 can be set in advance according to the specifications of the electric vehicle 10.

Subsequently, the vehicle control unit 50 calculates each torque command value of each drive MG based on the calculated target trajectory and the detected accelerator operation amount (S17).

Subsequently, the steering amount determination unit 46 calculates each steering amount command value of each steering unit 31 and 32 based on the calculated target trajectory (S18). Specifically, the steering amount command values of the steering units 31 and 32 are calculated so that the trajectory of the electric vehicle 10 becomes the target trajectory.

Subsequently, the torque determination unit 42 determines whether or not the torque command value of any of the drive MGs is larger than the upper limit value (S19). In this determination, when it is determined that the torque command values of all the drive MGs are not larger than the upper limit value (S19: NO), the torque determination unit 42 sets each torque command value as each final torque command value (S20). The steering amount determining unit 46 sets each steering amount command value as each final steering amount command value (S21). After that, the process of S13 is executed again. The drive control unit 41 controls each drive unit 21 and 22 based on each final torque command value, and the steering control unit 45 controls each steering unit 31 and 32 based on each final steering amount command value. do.

On the other hand, when it is determined in the determination of S19 that the torque command value of any of the drive MGs is larger than the upper limit value (S19: YES), the torque determination unit 42 sets the upper limit value as the final torque command value (S22). That is, the value obtained by limiting the torque command value by the upper limit value is set as the final torque command value (upper limit guard).

Subsequently, as described above, the steering amount determining unit 46 sets the first steering amount and the second steering amount as the final steering amount command values (S23). The drive control unit 41 controls each drive unit 21 and 22 based on each final torque command value, and the steering control unit 45 controls each steering unit 31 and 32 based on each final steering amount command value. do.

Subsequently, the vehicle control unit 50 determines whether or not the vehicle speed is 0 (S24). In this determination, if it is determined that the vehicle speed is not 0 (S24: NO), the process of S13 is executed again. On the other hand, in this determination, when it is determined that the vehicle speed is 0 (S24: YES), this series of processes is terminated (END).

The present embodiment described in detail above has the following advantages.

The abnormality determination unit 44 detects a drive abnormality in which one of the pair of left and right drive MGs can output only an abnormal torque different from the corresponding torque command value calculated by the vehicle control unit 50. When a drive abnormality is not detected by the abnormality determination unit 44, the steering amount determination unit 46 of the steering units 31 and 32 based on each torque command value calculated by the vehicle control unit 50 and the intended traveling state. Calculate each steering amount. Then, the steering control unit 45 steers the steering units 31 and 32 based on the steering amount calculated by the steering amount determining unit 46. Therefore, the steering units 31 and 32 can be steered so that the traveling state of the electric vehicle 10 becomes the intended traveling state.

The steering amount determination unit 46 has a torque command value, an abnormal torque, and a torque command value corresponding to a drive MG excluding the abnormal drive MG, which is a drive MG that can output only an abnormal torque when a drive abnormality is detected by the abnormality determination unit 44. Based on the intended driving state, one of the pair of left and right steering units 31 and 32 is calculated as the first steering amount, and the other steering amount is an absolute value rather than the absolute value of the first steering amount. Is calculated as the second steering amount with a small value. Then, the steering control unit 45 steers the steering units 31 and 32 based on the steering amounts (first steering amount and second steering amount) calculated by the steering amount determination unit 46. Let me. Therefore, even when a drive abnormality is detected by the abnormality determination unit 44, the electric vehicle 10 is intended based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG. The steering units 31 and 32 can be steered so as to approach the traveling state.

Furthermore, the absolute value of the second steering amount is smaller than the absolute value of the first steering amount. Therefore, the influence of the second steering amount on the traveling state of the electric vehicle 10 is suppressed, and the traveling state of the electric vehicle 10 can be easily controlled by adjusting the first steering amount. Therefore, even if an abnormality occurs in the drive MG of one of the left and right wheels 11 and 12 (driving wheels), it is possible to easily drive the electric vehicle 10 in the traveling state intended by the user. ..

The steering amount determination unit 46 drives abnormally when the intended traveling state is straight, a drive abnormality is detected by the abnormality determination unit 44, and the abnormal torque is smaller than the torque command value corresponding to the abnormal drive MG. Based on the torque command value, abnormal torque, and intended running state corresponding to the drive MG excluding the MG, as shown in the forward straight direction in FIG. 3, the steering amount of the steering unit 32 on the same side as the abnormal drive MG is used. A certain first steering amount is set to a steering amount in which the wheels 12 are directed to the left and right opposite sides of the abnormal drive MG. Therefore, the electric vehicle 10 that intends to turn to the same side as the abnormal drive MG can be brought closer to straight ahead.

-As shown in the forward straight movement in FIG. 3, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 31 on the opposite side to the abnormal drive MG, to 0. Therefore, the steering unit 31 on the opposite side of the abnormal drive MG can be controlled in the same manner as when no drive abnormality is detected, and the influence of the second steering amount on the running state of the electric vehicle 10. By adjusting the first steering amount, it becomes easier to finely control the traveling state of the electric vehicle 10.

As shown in the front left turn and the front right turn in FIG. 3, the steering amount determination unit 46 is in the intentional running state of turning, the abnormality determination unit 44 detects a drive abnormality, and the abnormality torque is abnormal. When it is smaller than the torque command value corresponding to the drive MG, the steering unit on the left and right opposite sides of the abnormal drive MG is based on the torque command value corresponding to the drive MG excluding the abnormal drive MG, the abnormal torque, and the intended running state. The first steering amount, which is the steering amount of 31, is set to the steering amount corresponding to the turning. Therefore, the electric vehicle 10 that is about to deviate from the turning trajectory of the electric vehicle 10 intended by the user can be brought closer to the turning trajectory of the electric vehicle 10 intended by the user.

Further, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 32 on the same side as the abnormal drive MG, to 0. Therefore, the influence of the second steering amount on the traveling state of the electric vehicle 10 is suppressed, and the traveling state of the electric vehicle 10 can be easily controlled by adjusting the first steering amount.

The abnormality determination unit 44 detects a restricted state in which an abnormality related to one of the pair of left and right drive MGs occurs and the torque output by one of the drive MGs is restricted so as not to exceed the upper limit value. In the limited state, when the torque command value is larger than the upper limit value, the output torque is limited so as not to exceed the upper limit value. Therefore, the abnormality determination unit 44 is driven when the restriction state is detected by the abnormality determination unit 44 and the torque command value corresponding to the drive MG whose torque is restricted so as not to exceed the upper limit value is larger than the upper limit value. Detect anomalies. Then, when a drive abnormality is detected by the abnormality determination unit 44, the steering amount determination unit 46 determines the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG, as described above. The steering amount of one of the pair of left and right steering units 31 and 32 is calculated as the first steering amount, and the steering amount of the other is smaller than the absolute value of the first steering amount. 2 Calculated as the amount of steering. Therefore, the traveling state of the electric vehicle 10 can be brought closer to the intended traveling state.

-Even in the limited state, if the torque command value is smaller than the upper limit value, the torque of the torque command value can be output even if the drive MG is restricted so that the torque does not exceed the upper limit value. can. In this regard, in the steering amount determination unit 46, the torque command value corresponding to the drive MG whose restricted state is detected by the abnormality determination unit 44 and whose torque is restricted so as not to exceed the upper limit value is smaller than the upper limit value. In this case, each steering amount of each steering unit 31 and 32 is calculated based on each torque command value calculated by the vehicle control unit 50 and the intended traveling state. Therefore, the electric vehicle 10 can be driven in the intended traveling state.

Note that the above embodiment can be modified and implemented as follows. The same parts as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in the forward straight direction of FIG. 7, in the steering amount determination unit 46, the intended traveling state is straight, the drive abnormality is detected by the abnormality determination unit 44, and the abnormal torque corresponds to the abnormal drive MG. When it is smaller than the command value, the steering amount of the steering unit 31 on the opposite side to the abnormal drive MG is based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG. A certain first steering amount may be a steering amount that directs the wheels 11 to the left and right opposite sides of the abnormal drive MG. As a result, the electric vehicle 10 that intends to turn to the same side as the abnormal drive MG can be brought closer to straight ahead. Then, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 32 on the same side as the abnormal drive MG, to 0 (the absolute value is smaller than the absolute value of the first steering amount). The amount of steering). As a result, the steering unit 32 on the same side as the abnormal drive MG can be controlled in the same manner as when no drive abnormality is detected, and the influence of the second steering amount on the running state of the electric vehicle 10. By adjusting the first steering amount, it becomes easier to finely control the traveling state of the electric vehicle 10.

As shown in the front left turn and the front right turn in FIG. 7, the steering amount determination unit 46 is in the intentional running state of turning, the abnormality determination unit 44 detects a drive abnormality, and the abnormality torque is abnormal. When it is smaller than the torque command value corresponding to the drive MG, the steering unit on the same side as the abnormal drive MG on the left and right sides based on the torque command value corresponding to the drive MG excluding the abnormal drive MG, the abnormal torque, and the intended running state. The first steering amount, which is the steering amount of 32, may be the steering amount corresponding to the turning. As a result, the electric vehicle 10 that is about to deviate from the turning trajectory of the electric vehicle 10 intended by the user can be brought closer to the turning trajectory of the electric vehicle 10 intended by the user.

As shown in the front right turn in FIG. 8, the steering amount determining unit 46 outputs only an abnormal torque in the intended traveling state when the intended traveling state is turning, a drive abnormality is detected by the abnormality determination unit 44, and the intended traveling state is an abnormal torque. When turning to the same side as the abnormal drive MG, which is a drive MG that cannot be performed, the steering amount of each of the steering units 31 and 32 may be set to 0. According to such a configuration, the steering units 31 and 32 try to drive the electric vehicle 10 straight with the wheels 11 and 12 facing the front of the electric vehicle 10. However, since one of the pair of left and right drive MGs can output only an abnormal torque smaller than the corresponding torque command value calculated by the vehicle control unit 50, the electric vehicle 10 is on the same side as the abnormal drive MG (right side in FIG. 8). ) Try to turn. Therefore, while suppressing the influence of each of the steering units 31 and 32 on the running state of the electric vehicle 10, the electric vehicle 10 uses the difference in torque output by the left and right drive MGs in the direction of turning intended by the user. Can be swiveled.

Further, the vehicle control unit 50 is abnormally driven when the intended driving state is turning, the abnormality determining unit 44 detects a driving abnormality, and the intended driving state is turning to the same side as the abnormal driving MG. Even if each torque command value of the drive MG excluding the abnormal drive MG (the drive MG of the wheel 11 in FIG. 8) is calculated based on the torque command value corresponding to the drive MG excluding the MG, the abnormal torque, and the intended running state. good. Specifically, the torque command value of the drive MG of the wheel 11 is calculated so that the turning trajectory of the electric vehicle 10 approaches the turning trajectory intended by the user. According to such a configuration, the torque of the drive MG is controlled while the steering amount of the steering units 31 and 32 is set to 0 to suppress the influence of the steering units 31 and 32 on the running state of the electric vehicle 10. Also, the turning trajectory of the electric vehicle 10 can be brought closer to the turning trajectory intended by the user.

・ When a drive abnormality occurs, the track on which the electric vehicle 10 travels deviates from the target track. When the electric vehicle 10 is traveling at a speed higher than the first speed (for example, 40 [km / h]), if the track of the electric vehicle 10 is suddenly brought close to the target track, it is excessive for the driver of the electric vehicle 10. Centrifugal force may act.

Therefore, as shown in FIG. 9, the vehicle control unit 50 is in the case where the intended traveling state is turning, the abnormality determination unit 44 detects a drive abnormality, and the speed of the electric vehicle 10 is higher than the first speed. Based on the torque command value, abnormal torque, and target trajectory corresponding to the drive MG excluding the abnormal drive MG, the abnormal drive MG so that the track on which the electric vehicle 10 travels gradually approaches the target track from the outside of the target track. Each torque command value of the drive MG excluding the above may be calculated. Further, when the intentional running state is turning, the abnormality determination unit 44 detects a drive abnormality, and the speed of the electric vehicle 10 is higher than the first speed, the steering amount determination unit 46 performs the abnormal drive MG. Based on the torque command value, abnormal torque, and target trajectory corresponding to the drive MG to be excluded, the steering units 31 and 32 of the steering units 31 and 32 so as to gradually bring the track on which the electric vehicle 10 travels closer to the target track from the outside of the target track. Each steering amount may be calculated. As a result, it is possible to suppress the action of an excessive centrifugal force on the driver of the electric vehicle 10, and it is possible to suppress a decrease in riding comfort.

・ When a drive abnormality occurs, the track on which the electric vehicle 10 travels deviates from the target track. When the speed of the electric vehicle 10 is lower than the first speed and higher than the second speed (for example, 10 [km / h]) lower than the first speed, the track of the electric vehicle 10 is gradually brought closer to the target track. Even without it, it is difficult for an excessive centrifugal force to act on the driver of the electric vehicle 10.

Therefore, as shown in FIG. 10, in the vehicle control unit 50, the intended traveling state is turning, the drive abnormality is detected by the abnormality determination unit 44, and the speed of the electric vehicle 10 is lower than the first speed and the first speed. When the speed is higher than the second speed, which is lower than the first speed, the track on which the electric vehicle 10 travels is outside the target track based on the torque command value, the abnormal torque, and the target track corresponding to the drive MG excluding the abnormal drive MG. And each torque command value of the drive MG excluding the abnormal drive MG may be calculated so as to bring the track on which the electric vehicle 10 travels closer to the target track while allowing the electric vehicle 10 to be inside. Further, in the steering amount determining unit 46, the intended traveling state is turning, the driving abnormality is detected by the abnormality determining unit 44, and the speed of the electric vehicle 10 is lower than the first speed and higher than the second speed. In this case, based on the torque command value, the abnormal torque, and the target trajectory corresponding to the drive MG excluding the abnormal drive MG, the electric vehicle 10 allows the track on which the electric vehicle 10 travels to be outside and inside the target track. The steering amount of each of the steering units 31 and 32 may be calculated so that the track on which the vehicle 10 travels approaches the target track. As a result, when it is difficult for an excessive centrifugal force to act on the driver of the electric vehicle 10, the track on which the electric vehicle 10 travels can be quickly brought closer to the target track.

When the speed of the electric vehicle 10 is lower than the first speed and higher than the second speed, the same control as when the speed of the electric vehicle 10 described above is higher than the first speed can be executed. Further, when the speed of the electric vehicle 10 is higher than the first speed, the same control as when the speed of the electric vehicle 10 is lower than the first speed and higher than the second speed can be executed.

・ When a drive abnormality occurs, the track on which the electric vehicle 10 travels deviates from the target track. When the speed of the electric vehicle 10 is lower than the second speed, the centrifugal force acting on the driver of the electric vehicle 10 is small, so that it is not necessary to control the speed of the electric vehicle 10.

Therefore, when the intentional running state is turning, the abnormality determination unit 44 detects a drive abnormality, and the speed of the electric vehicle 10 is lower than the second speed, the steering amount determination unit 46 performs the abnormal drive MG. Based on the torque command value, abnormal torque, and target trajectory corresponding to the drive MG to be excluded, the steering amounts of the steering units 31 and 32 are calculated so as to bring the trajectory on which the electric vehicle 10 travels closer to the target trajectory. May be good. As a result, when the need to control the speed of the electric vehicle 10 is low, it is not necessary to calculate each torque command value of the drive MG excluding the abnormal drive MG based on the target trajectory, and the control load of the drive system is reduced. be able to. When the speed of the electric vehicle 10 is lower than the second speed, the same control as when the speed of the electric vehicle 10 described above is lower than the first speed and higher than the second speed can be executed.

-It is possible that both the pair of left and right drive MGs can output only a common predetermined torque that is smaller than each torque command value. In this case, since the torques output by the pair of left and right drive MGs do not differ significantly, it is less necessary to calculate the steering amounts of the pair of left and right steering units 31 and 32 as different steering amounts.

Therefore, the abnormality determination unit 44 detects both drive abnormalities in which both the left and right pair of drive MGs can output a common predetermined torque smaller than the corresponding torque command value calculated by the vehicle control unit 50, and the steering amount. When both drive abnormalities are detected by the abnormality determination unit 44, the determination unit 46 may calculate the steering amount of each of the steering units 31 and 32 based on the predetermined torque and the intended traveling state. As a result, the processing load on which the steering amount determining unit 46 calculates each steering amount can be reduced.

-As shown in FIG. 11, when the electric vehicle 10 moves backward, the same control as in the above embodiment may be executed. Specifically, in the steering amount determination unit 46, the intended traveling state is straight backward, the drive abnormality is detected by the abnormality determination unit 44, and the abnormal torque is smaller than the torque command value corresponding to the abnormal drive MG. In this case, based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG, as shown in the backward straight direction of FIG. 11, the steering unit 32 on the same side as the abnormal drive MG on the left and right sides. The first steering amount, which is the steering amount of, is set to the steering amount at which the wheels 12 are directed to the left and right opposite sides of the abnormal drive MG. As a result, the electric vehicle 10 that intends to turn to the same side as the abnormal drive MG can be brought closer to straight ahead. The abnormal drive MG and the left-right opposite side are the left-right opposite sides with respect to the traveling direction. For example, when the forward straight and the right drive MG is the abnormal drive MG, the front part of the wheel is turned to the left and the rear If the drive MG that goes straight and is on the right is an abnormal drive MG, turn the rear part of the wheel to the left. Further, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 31 on the left and right opposite sides of the abnormal drive MG, to 0 (first steering), as shown in the rear straight direction of FIG. The amount of steering whose absolute value is smaller than the absolute value of the amount). As a result, the steering unit 31 on the opposite side of the abnormal drive MG can be controlled in the same manner as when no drive abnormality is detected, and the influence of the second steering amount on the running state of the electric vehicle 10. By adjusting the first steering amount, it becomes easier to finely control the traveling state of the electric vehicle 10.

As shown in the rear left turn and the rear right turn in FIG. 11, in the steering amount determination unit 46, the intended traveling state is the rear turn, the abnormality determination unit 44 detects a drive abnormality, and the abnormality torque is abnormal. When it is smaller than the torque command value corresponding to the drive MG, the steering unit on the left and right opposite sides of the abnormal drive MG is based on the torque command value corresponding to the drive MG excluding the abnormal drive MG, the abnormal torque, and the intended running state. The first steering amount, which is the steering amount of 31, is set to the steering amount corresponding to the turning. As a result, the electric vehicle 10 that is about to deviate from the turning trajectory of the electric vehicle 10 intended by the user can be brought closer to the turning trajectory of the electric vehicle 10 intended by the user. Further, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 32 on the same side as the abnormal drive MG, to 0 (the absolute value is smaller than the absolute value of the first steering amount). The amount of steering). Therefore, the influence of the second steering amount on the traveling state of the electric vehicle 10 is suppressed, and the traveling state of the electric vehicle 10 can be easily controlled by adjusting the first steering amount.

As shown in the backward straight movement of FIG. 12, the steering amount determination unit 46 is in the intended running state of the rear straight movement, a drive abnormality is detected by the abnormality determination unit 44, and the abnormal torque corresponds to the abnormal drive MG. When it is smaller than the command value, the steering amount of the steering unit 31 on the opposite side to the abnormal drive MG is based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG. A certain first steering amount may be a steering amount in which the wheels 11 are directed to the same side as the abnormal drive MG on the left and right. As a result, the electric vehicle 10 that intends to turn backward to the same side as the abnormal drive MG can be brought closer to the backward straight direction. Then, the steering amount determining unit 46 sets the second steering amount, which is the steering amount of the steering unit 32 on the same side as the abnormal drive MG, to 0 (the absolute value is smaller than the absolute value of the first steering amount). The amount of steering). As a result, the steering unit 32 on the same side as the abnormal drive MG can be controlled in the same manner as when no drive abnormality is detected, and the influence of the second steering amount on the running state of the electric vehicle 10. By adjusting the first steering amount, it becomes easier to finely control the traveling state of the electric vehicle 10.

As shown in the rear left turn and the rear right turn in FIG. 12, the steering amount determination unit 46 has an intentional running state of rear turn, an abnormality determination unit 44 detects a drive abnormality, and an abnormality torque is abnormal. When it is smaller than the torque command value corresponding to the drive MG, the steering unit on the same side as the abnormal drive MG on the left and right sides based on the torque command value corresponding to the drive MG excluding the abnormal drive MG, the abnormal torque, and the intended running state. The first steering amount, which is the steering amount of 32, may be set to the steering amount corresponding to the rear turning. As a result, the electric vehicle 10 that is about to deviate from the turning trajectory of the electric vehicle 10 intended by the user can be brought closer to the turning trajectory of the electric vehicle 10 intended by the user.

As shown in the rear right turn of FIG. 13, in the steering amount determination unit 46, the intended traveling state is the rear turning, the abnormality determination unit 44 detects a drive abnormality, and the intended traveling state is only abnormal torque. When the rear turn is to the same side as the abnormal drive MG, which is a drive MG that cannot be output, the steering amount of each of the steering units 31 and 32 may be set to 0. According to such a configuration, the steering units 31 and 32 try to direct the wheels 11 and 12 to the rear front of the electric vehicle 10 and to drive the electric vehicle 10 backward and straight. However, since one of the pair of left and right drive MGs can output only an abnormal torque smaller than the corresponding torque command value calculated by the vehicle control unit 50, the electric vehicle 10 is on the same side as the abnormal drive MG on the left and right sides (right side in FIG. 13). ) To turn backwards. Therefore, while suppressing the influence of the steering units 31 and 32 on the running state of the electric vehicle 10, the difference in torque output by the left and right drive MGs is used to drive the electric vehicle in the direction of the rear turn intended by the user. 10 can be turned.

As shown in FIGS. 14 to 17, it can be embodied in the drive system of the electric vehicle 10 in which the wheels 11 and 12 are the steering wheels and the driven wheels and the wheels 13 and 14 are the driving wheels. FIG. 14 shows the operation of the steering mechanism in a normal state in a rear-wheel drive vehicle.

FIG. 15 shows the operation of the steering mechanism at the time of abnormality. In this case, the wheels 11 and 12 on the front side are subjected to the same steering control as in the embodiment shown in FIG. That is, the drive wheels may be the front wheels or the rear wheels of the electric vehicle 10. Further, with respect to the wheels 13 and 14 on the rear side, the torque of the abnormal drive MG of the wheels 14 is limited by an upper limit value. Even with such a configuration, it is possible to obtain an action and effect according to the embodiment shown in FIG.

In FIG. 16, steering control is performed on the front wheels 11 and 12 in the same manner as in the embodiment shown in FIG. Even with such a configuration, it is possible to exert an action effect according to the embodiment shown in FIG.

In FIG. 17, steering control is performed on the front wheels 11 and 12 in the same manner as in the embodiment shown in FIG. Even with such a configuration, it is possible to exert an action effect according to the embodiment shown in FIG.

As shown in FIGS. 18 to 20, the wheels 11 and 12 are the driving wheels and the steering wheels, and the wheels 13 and 14 are the driving wheels and the steering wheels, which can be embodied in the drive system of the electric vehicle 10. Here, an example in which the wheels 12 and 13 become abnormal wheels is shown.

FIG. 18 shows the operation of the steering mechanism at the time of abnormality. In this case, the wheels 11 and 12 on the front side are subjected to the same steering control as in the embodiment shown in FIG. That is, the drive wheels may be the front wheels and the rear wheels of the electric vehicle 10. Further, the rear wheels 13 and 14 are controlled to bring the traveling state of the electric vehicle 10 closer to the intended traveling state by combining the steering control with respect to the front wheels 11 and 12.

In FIG. 19, steering control is performed on the front wheels 11 and 12 in the same manner as in the embodiment shown in FIG. Even with such a configuration, it is possible to exert an action effect according to the embodiment shown in FIG. Further, by combining the steering control with respect to the rear wheels 13 and 14, the rear wheels 13 and 14, and the steering control with respect to the front wheels 11 and 12, the traveling state of the electric vehicle 10 is changed to the intended traveling state. You are performing close control.

In FIG. 20, steering control is performed on the front wheels 11 and 12 in the same manner as in the embodiment shown in FIG. Even with such a configuration, it is possible to exert an action effect according to the embodiment shown in FIG. Further, by combining the steering control with respect to the rear wheels 13 and 14, the rear wheels 13 and 14, and the steering control with respect to the front wheels 11 and 12, the traveling state of the electric vehicle 10 is changed to the intended traveling state. You are performing close control.

As shown in FIGS. 21 to 23, it can be embodied in the drive system of the electric vehicle 10 in which the wheels 11 and 12 are the driving wheels and the steering wheels, and the wheels 13 and 14 are the driving wheels and the steering wheels. Here, an example is shown in which the wheels 12 and 14 become abnormal wheels.

FIG. 21 shows the operation of the steering mechanism at the time of abnormality. In this case, the wheels 11 and 12 on the front side are subjected to the same steering control as in the embodiment shown in FIG. That is, the drive wheels may be the front wheels and the rear wheels of the electric vehicle 10. Further, the rear wheels 13 and 14 are controlled to bring the traveling state of the electric vehicle 10 closer to the intended traveling state by combining the steering control with respect to the front wheels 11 and 12.

In FIG. 22, steering control is performed on the front wheels 11 and 12 in the same manner as in the embodiment shown in FIG. Even with such a configuration, it is possible to exert an action effect according to the embodiment shown in FIG. Further, by combining the steering control with respect to the rear wheels 13 and 14, the rear wheels 13 and 14, and the steering control with respect to the front wheels 11 and 12, the traveling state of the electric vehicle 10 is changed to the intended traveling state. You are performing close control.

In FIG. 23, the steering control of the front wheels 11 and 12 and the rear wheels 13 and 14 is performed in the same manner as in the embodiment shown in FIG. Even with such a configuration, it is possible to exert an action effect according to the embodiment shown in FIG.

When the abnormality determination unit 44 has not detected a drive abnormality, the vehicle control unit 50 calculates each torque command value of each drive MG based on the intended driving state, and the abnormality determination unit 44 detects the drive abnormality. In this case, each torque command value of the drive MG excluding the abnormal drive MG may be calculated based on the torque command value, the abnormal torque, and the intended running state corresponding to the drive MG excluding the abnormal drive MG. That is, in consideration of the torque generated by the drive MG excluding the abnormal drive MG and the abnormal torque generated by the abnormal drive MG, each torque of the drive MG excluding the abnormal drive MG so as to drive the electric vehicle 10 in the intended running state. Calculate the command value. According to such a configuration, the turning trajectory of the vehicle can be brought closer to the turning trajectory intended by the user by controlling the torque of the drive MG.

-The vehicle control unit 50 may have the function of the abnormality determination unit 44. The vehicle control unit 50 may have the function of the torque determination unit 42. The vehicle control unit 50 may have the function of the steering amount determining unit 46. Further, the torque determination unit 42 may have a function of the vehicle control unit 50 to calculate the torque command value. The steering amount determining unit 46 may have a function of the vehicle control unit 50 calculating the steering amount command value.

・ As a drive abnormality, the drive MG may output only an abnormal torque larger than the torque command value. Even in this case, the abnormality determination unit 44 outputs only an abnormal torque (torque larger than the torque command value) different from the corresponding torque command value calculated by the vehicle control unit 50 on one of the pair of left and right drive MGs. Detects a drive abnormality that cannot be performed. The steering amount determination unit 46 has a torque command value, an abnormal torque, and an intention corresponding to a drive MG excluding the abnormal drive MG, which is a drive MG that can output only an abnormal torque when a drive abnormality is detected by the abnormality determination unit 44. Based on the traveling state, the steering amount of one of the pair of left and right steering units 31 and 32 is calculated as the first steering amount, and the other steering amount is an absolute value rather than the absolute value of the first steering amount. Calculated as a small second steering amount. According to such a configuration, even when a drive abnormality is detected by the abnormality determination unit 44, the electric vehicle is based on the torque command value, the abnormal torque, and the intended driving state corresponding to the drive MG excluding the abnormal drive MG. The steering units 31 and 32 can be steered so as to bring the 10 closer to the intended traveling state. Further, the absolute value of the second steering amount is smaller than the absolute value of the first steering amount. Therefore, the influence of the second steering amount on the traveling state of the electric vehicle 10 is suppressed, and the traveling state of the electric vehicle 10 can be easily controlled by adjusting the first steering amount.

The above embodiments are executed not only when the driver (user) drives the electric vehicle 10 but also when the vehicle control unit 50 executes constant speed running control for driving the electric vehicle 10 at a constant speed. You can also do it. Further, each of the above embodiments can be executed when the vehicle control unit 50 is executing the follow-up travel control for causing the electric vehicle 10 to follow the preceding vehicle. Further, each of the above embodiments can be executed when the vehicle control unit 50 is executing the automatic driving (running) control for automatically traveling the set route to the electric vehicle 10. In these controls, the intended driving state can be acquired based on the constant speed driving control setting, the following driving control setting, the automatic driving (driving) control setting, and the like. In the constant speed running control, the following running control, and the automatic driving control, the user may or may not be on the electric vehicle 10.

Although the present disclosure has been described in accordance with the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various modifications and modifications within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are also within the scope of the present disclosure.

Claims (11)

1. A pair of left and right drive motors (21, 22) that drive the left and right wheels (11 to 14) of the vehicle (10) independently of each other.
   A pair of left and right steering mechanisms (31, 32) that steer the left and right wheels of the vehicle independently of each other.
   A command value calculation unit (50) that calculates each torque command value of each drive motor based on the intended running state of the vehicle intended by the user.
   A drive control unit (41) that drives each drive motor based on each torque command value calculated by the command value calculation unit, and a drive control unit (41).
   An abnormality detection unit (43, 44) that detects a drive abnormality in which one of the pair of left and right drive motors can output only an abnormal torque different from the corresponding torque command value calculated by the command value calculation unit.
   When the drive abnormality is not detected by the abnormality detection unit, each steering amount of each steering mechanism is calculated based on the torque command value calculated by the command value calculation unit and the intended running state. When the drive abnormality is detected by the abnormality detection unit, the torque command value, the abnormality torque, and the intended running state corresponding to the drive motor excluding the abnormality motor which is a drive motor capable of outputting only the abnormality torque are obtained. Based on this, the steering amount of one of the pair of left and right steering mechanisms is calculated as the first steering amount, and the steering amount of the other is the second rotation whose absolute value is smaller than the absolute value of the first steering amount. The steering amount calculation unit (46, 50) that calculates the steering amount, and
   A steering control unit (45) that steers each steering mechanism based on each steering amount calculated by the steering amount calculation unit.
   Vehicle drive system.
2. The steering amount calculation unit is used when the intended traveling state is straight, the abnormality detection unit detects the drive abnormality, and the abnormality torque is smaller than the torque command value corresponding to the abnormality motor. The first steering, which is the steering amount of the steering mechanism on the same side as the abnormal motor, based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state. Claim 1 in which the amount is set to the amount of steering that directs the wheels to the left and right opposite sides of the abnormal motor, and the second steering amount, which is the amount of steering of the steering mechanism on the left and right opposite sides of the abnormal motor, is set to 0. The vehicle drive system described in.
3. The steering amount calculation unit is used when the intended traveling state is turning, the abnormality detection unit detects the drive abnormality, and the abnormality torque is smaller than the torque command value corresponding to the abnormality motor. The first steering, which is the steering amount of the steering mechanism on the left and right opposite sides of the abnormal motor, based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state. The vehicle according to claim 1 or 2, wherein the amount is set to a steering amount corresponding to the turning, and the second steering amount, which is the steering amount of the steering mechanism on the same side as the abnormal motor, is set to 0. Drive system.
4. When the drive abnormality is not detected by the abnormality detection unit, the command value calculation unit calculates each torque command value of each drive motor based on the intended running state, and the abnormality detection unit calculates the drive abnormality. Is detected, each torque command value of the drive motor excluding the abnormal motor is calculated based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the intended running state. , The vehicle drive system according to any one of claims 1 to 3.
5. A pair of left and right drive motors (21, 22) that drive the left and right wheels (11 to 14) of the vehicle (10) independently of each other.
   A pair of left and right steering mechanisms (31, 32) that steer the left and right wheels of the vehicle independently of each other.
   A command value calculation unit (50) that calculates each torque command value of each drive motor based on the intended running state of the vehicle intended by the user.
   A drive control unit (41) that drives each drive motor based on each torque command value calculated by the command value calculation unit, and a drive control unit (41).
   An abnormality detection unit (43, 44) for detecting a drive abnormality in which one of the pair of left and right drive motors can output an abnormal torque smaller than the corresponding torque command value calculated by the command value calculation unit.
   When the drive abnormality is not detected by the abnormality detection unit, each steering amount of each steering mechanism is calculated based on the torque command value calculated by the command value calculation unit and the intended running state. The intended running state is turning, the driving abnormality is detected by the abnormality detecting unit, and the intended running state is turning to the same side as the abnormal motor which is a drive motor capable of outputting only the abnormal torque. In this case, the steering amount calculation unit (46, 50) that sets each steering amount of each steering mechanism to 0, and
   A steering control unit (45) that steers each steering mechanism based on each steering amount calculated by the steering amount calculation unit.
   Vehicle drive system.
6. When the drive abnormality is not detected by the abnormality detection unit, the command value calculation unit calculates each torque command value of each drive motor based on the intention running state, and the intention running state is turning. When the drive abnormality is detected by the abnormality detection unit and the intended running state is turning to the same side as the abnormality motor, the torque command value corresponding to the drive motor excluding the abnormality motor, The vehicle drive system according to claim 5, wherein each torque command value of a drive motor other than the abnormal motor is calculated based on the abnormal torque and the intended running state.
7. A track calculation unit (50) for calculating a target track on which the vehicle travels based on the intended traveling state is provided.
   When the drive abnormality is not detected by the abnormality detection unit, the command value calculation unit calculates each torque command value of each drive motor so as to set the track on which the vehicle travels to the target track, and the intention When the traveling state is turning, the drive abnormality is detected by the abnormality detection unit, and the speed of the vehicle is higher than the first speed, the torque command value corresponding to the drive motor excluding the abnormality motor, Based on the abnormal torque and the target track, each torque command value of the drive motor excluding the abnormal motor is calculated so that the track on which the vehicle travels gradually approaches the target track from the outside of the target track. ,
   When the drive abnormality is not detected by the abnormality detection unit, the steering amount calculation unit calculates each steering amount of each steering mechanism so as to set the track on which the vehicle travels to the target track. When the intended running state is turning, the drive abnormality is detected by the abnormality detection unit, and the speed of the vehicle is higher than the first speed, the torque corresponding to the drive motor excluding the abnormality motor. Based on the command value, the abnormal torque, and the target track, each steering amount of each steering mechanism is calculated so that the track on which the vehicle travels gradually approaches the target track from the outside of the target track. The vehicle drive system according to any one of claims 1 to 6.
8. In the command value calculation unit, the intended traveling state is turning, the abnormality detection unit detects the drive abnormality, and the speed of the vehicle is lower than the first speed and lower than the first speed. When the speed is higher than the second speed, the track on which the vehicle travels is outside and inside the target track based on the torque command value, the abnormal torque, and the target track corresponding to the drive motor excluding the abnormal motor. The torque command values of the drive motors excluding the abnormal motor are calculated so as to bring the track on which the vehicle travels closer to the target track.
   In the steering amount calculation unit, the intended traveling state is turning, the abnormality detection unit detects the drive abnormality, and the speed of the vehicle is lower than the first speed and higher than the second speed. When it is high, it is allowed that the track on which the vehicle travels is outside and inside the target track based on the torque command value corresponding to the drive motor excluding the abnormal motor, the abnormal torque, and the target track. The vehicle drive system according to claim 7, wherein each steering amount of each steering mechanism is calculated so that the track on which the vehicle travels is brought closer to the target trajectory.
9. The steering amount calculation unit uses the abnormal motor when the intended traveling state is turning, the abnormality detecting unit detects the driving abnormality, and the speed of the vehicle is lower than the second speed. Based on the torque command value, the abnormal torque, and the target track corresponding to the drive motors to be excluded, each steering amount of each steering mechanism is calculated so as to bring the track on which the vehicle travels closer to the target track. The vehicle drive system according to claim 8.
10. A limitation detection unit (44) for detecting a limited state in which an abnormality related to one of the pair of left and right drive motors occurs and the torque output by the one drive motor is restricted so as not to exceed the upper limit value is provided. ,
    In the abnormality detection unit, when the limited state is detected by the limited detection unit and the torque command value corresponding to the drive motor whose torque is restricted so as not to exceed the upper limit value is larger than the upper limit value. Detects the drive abnormality and
    In the steering amount calculation unit, the torque command value corresponding to the drive motor whose limited state is detected by the limited detection unit and the torque is restricted so as not to exceed the upper limit value is higher than the upper limit value. In any one of claims 1 to 9, the steering amount of each steering mechanism is calculated based on the torque command value calculated by the command value calculation unit and the intended running state when the value is small. The vehicle drive system described.
11. The abnormality detection unit detects both drive abnormalities in which both the left and right drive motors can output a common predetermined torque smaller than the corresponding torque command value calculated by the command value calculation unit.
    The steering amount calculation unit calculates each steering amount of each steering mechanism based on the predetermined torque and the intended running state when both drive abnormalities are detected by the abnormality detecting unit. The vehicle drive system according to any one of 1 to 10.

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