JP2014093844A - Electric-vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric-vehicle control device enabling an electric vehicle to self-travel to a destination in the case of abnormality occurring to a wheel-specific drive system.SOLUTION: An electric-vehicle control device A includes: basic drive instruction means 20 for issuing a motor-specific output instruction distributedly to electric motors 6 in response to an output instruction input from accelerator input means 16; individual drive system abnormality detection means 23 for detecting occurrence of abnormality in a wheel-specific drive system for each of individual drive wheels; at-abnormality other motor output limiting means 27 for limiting output of an electric motor 6 of another wheel-specific drive system when the individual drive system abnormality detection means 23 detects abnormality occurring to any one wheel drive system. The at-abnormality other motor output limiting means 27 calculates a load required for the electric vehicle to travel and limits an output of the electric motor 6 in accordance with a predetermined rule.

Description

  The present invention relates to an electric vehicle control device, for example, to a technique capable of reducing the load on a normal wheel and making it self-run to a destination when an electric motor that drives the wheel is abnormal.

In an electric vehicle, the following technique has been proposed as a control method when an electric motor driving a wheel is abnormal.
1. When an abnormality occurs in an in-wheel motor that drives a wheel, a technique for preventing vehicle deflection by bringing the normal coaxially symmetric motor driving force closer to the motor driving force in which the abnormality occurred (patent) Reference 1).
2. A technique has been proposed in which the balance change is compensated by a steering mechanism when the balance of the driving force changes due to an abnormality in an electric motor or the like that drives the wheels (Patent Document 2).

Japanese Patent No. 4412476 JP 2012-176663 A

  In the prior art, the friction load is concentrated on the normal wheel, and the load on the normal electric motor may be excessive. In such a case, if a demagnetization occurs in the permanent magnet of the electric motor due to a failure caused by the friction load of the wheel or the load of the electric motor, for example, the electric vehicle cannot self-propel to a destination such as a repair shop There is a fear.

  An object of the present invention is to provide an electric vehicle control device capable of self-propelling by an electric vehicle to a destination when an abnormality occurs in the drive system for each wheel.

  The electric vehicle control apparatus according to the present invention includes a plurality of electric motors 6 and 6 that respectively drive a pair of left and right drive wheels 2 and 2, and a driving force is transmitted from the electric motors 6 and 6 to the drive wheels 2 and 2. In the electric vehicle control apparatus for controlling an electric vehicle provided with the transmission mechanism 7 that performs the basic drive, the motor-specific output command is distributed to the electric motors 6 and 6 in accordance with the output command input from the accelerator input means 16. Command means 20, individual drive system abnormality detection means 23 for detecting that an abnormality has occurred in the wheel-by-wheel drive system comprising the electric motor 6, the transmission mechanism 7 and the drive wheel 2 for each drive wheel; When it is detected by the individual drive system abnormality detection means 23 that an abnormality has occurred in any one of the wheel drive systems, the other mode at the time of abnormality that restricts the output of the electric motor 6 of the other wheel drive system. Output control means 27, and the abnormal motor output restriction means 27 calculates a load necessary for traveling of the electric vehicle and limits the output of the electric motor 6 according to a predetermined rule. Features.

  According to this configuration, the basic drive command means 20 distributes to each of the electric motors 6 and 6 according to the output command input from the accelerator input means 16 and gives a motor-specific output command. When the individual drive system abnormality detection means 23 detects that an abnormality has occurred in the drive system for each wheel, the other motor output restriction means 27 in response to the output command given by the basic drive command means 20 in response to the other wheel. Limit the output of the electric motor 6 of each drive system. The abnormal-time other motor output limiting means 27 calculates a load necessary for traveling of the electric vehicle, and limits the output of the electric motor 6 according to a predetermined rule. Thus, even if an abnormality occurs in the drive system for each wheel, the electric vehicle can be more reliably self-propelled to the destination by calculating the load necessary for traveling the electric vehicle.

Road surface friction coefficient estimating means 24 for estimating the friction coefficient of the road surface, slip angle estimating means 25 for estimating a slip angle, which is a turning angle with respect to the traveling direction of the vehicle, in the steered wheels 3, and the vehicle body with respect to the traveling direction of the vehicle A vehicle body bend amount detecting means 26 for detecting a bend amount is provided, and the abnormal other motor output restricting means 27 is configured so that the road surface friction coefficient estimating means 24 and the slip angle estimating means 25 estimate the road surface friction coefficient. The amount of wear of the steered wheel 3 is calculated from the estimated slip angle and the amount of bending of the vehicle body 1 detected by the vehicle body bending amount detection means 26, and when the amount of wear exceeds a predetermined threshold, The output of the electric motor 6 of each wheel drive system may be limited.
In this case, the abnormal motor output limiting means 27 calculates the output of the electric motor 6 by calculating, for example, the amount of tire wear of the steered wheels 3 as a load necessary for traveling of the electric vehicle and comparing it with a threshold value. It can be limited with high accuracy. The threshold value is determined based on, for example, the amount of wear that causes the tires of the steered wheels 3 to be unable to travel when an abnormality occurs in the drive system for each wheel by testing or simulation.

  A current detection means 35 for detecting a current value flowing to the electric motor 6 of the other wheel-by-wheel drive system and a temperature detection means 49 for detecting the temperature of the electric motor 6 are provided, and the other motor output limiting means 27 for the abnormality is provided. Is the other wheel-by-wheel drive system so that when the temperature detected by the temperature detecting means 49 is equal to or higher than a predetermined threshold, the current value detected by the current detecting means 35 is less than or equal to the predetermined current value. The output of the electric motor 6 may be limited. By limiting the output of the electric motor 6 in this way, for example, the electric vehicle is undesirably stopped due to demagnetization of the permanent magnet of the electric motor 6 during traveling to a destination such as a repair shop. Can be avoided. The threshold is determined based on the motor temperature when demagnetization occurs in the permanent magnet of the electric motor 6 of the other wheel-by-wheel drive system, for example, when the wheel-by-wheel drive system is abnormal by testing or simulation.

  A reduction gear 7 is provided as the transmission mechanism, and the drive system for each wheel transmits the wheel bearing 4 that supports the drive wheel 2, the electric motor 6, and the drive of the electric motor 6 to the wheel bearing 4. The in-wheel motor drive device 8 may be configured with the reduction gear 7.

  Vehicle behavior estimation means for estimating the behavior of the vehicle, and when the individual drive system abnormality detection means 23 detects that an abnormality has occurred in any one of the wheel drive systems, before the occurrence of the abnormality The steered wheels 3 of the electric vehicle so that there is no change between the behavior of the vehicle estimated by the vehicle behavior estimation means and the behavior of the vehicle estimated by the vehicle behavior estimation means after an abnormality has occurred. You may provide the turning angle adjustment means 30 which can adjust the turning angle of.

  The vehicle behavior estimation means may be a vehicle body bending amount detection means 26 for detecting a vehicle body bending amount (yaw moment) with respect to the traveling direction of the vehicle as the vehicle behavior. When an abnormality occurs in one wheel drive system, a yaw moment is generated around the center of gravity of the electric vehicle. For this reason, the turning angle adjusting means 30 adjusts the turning angle of the steered wheels 3 so as to cancel the generated yaw moment with a yaw moment in the opposite direction. Thereby, the traveling state of the vehicle can be maintained so that there is no change in the traveling direction of the vehicle before and after the occurrence of the abnormality. For example, if the vehicle is in a straight traveling state before the abnormality occurs, the vehicle can be maintained in a straight traveling state even after the abnormality has occurred.

  An electric vehicle control device according to the present invention controls an electric vehicle including a plurality of electric motors that respectively drive a pair of left and right drive wheels, and a transmission mechanism that transmits a driving force from the electric motors to the drive wheels. In the electric vehicle control apparatus, basic drive command means that distributes to the electric motor in accordance with an output command input from an accelerator input means and gives a motor-specific output command, the electric motor for each drive wheel, and the transmission mechanism And an individual drive system abnormality detection means for detecting that an abnormality has occurred in the drive system for each wheel comprising the drive wheels, and an abnormality has occurred in either one of the wheel drive systems by the individual drive system abnormality detection means. Is detected, an abnormal-time other motor output limiting means for limiting the output of the electric motor of the other wheel-by-wheel drive system is provided. The abnormal-time other motor output limiting means calculates a load necessary for traveling of the electric vehicle and limits the output of the electric motor according to a predetermined rule. For this reason, when an abnormality occurs in the drive system for each wheel, the electric vehicle can self-propel to the destination.

1 is a block diagram of a conceptual configuration showing an electric vehicle control device according to a first embodiment of the present invention in a plan view of the electric vehicle. It is a block diagram of the principal part of the same electric vehicle control apparatus. It is a block diagram which shows conceptual composition, such as an in-wheel motor drive device of the same electric vehicle. (A) is a block diagram schematically showing the configuration of an electric vehicle when both wheel drive systems are normal, and (B) is an operation explanatory diagram when one wheel drive system is abnormal. It is a flowchart which shows the example which restrict | limits the output of the electric motor of the same electric vehicle control apparatus. It is a block diagram which shows the conceptual structure of the principal part of the electric vehicle control apparatus which concerns on other embodiment of this invention. It is a flowchart which shows the example which restrict | limits the output of the electric motor of the same electric vehicle control apparatus.

An electric vehicle control apparatus according to a first embodiment of the present invention will be described with reference to FIGS. The following description also includes a description of a control method for the electric vehicle.
As shown in FIG. 1, the electric vehicle is a four-wheeled electric vehicle in which left and right rear wheels and wheels of a vehicle body 1 are drive wheels 2 and left and right front wheels are driven wheels 3 that are driven wheels. is there. The wheels that serve as the drive wheels 2 and the steered wheels 3 both have tires and are supported by the vehicle body 1 via wheel bearings 4 (FIG. 3) and 5, respectively. The wheel bearing 5 is abbreviated as “H / B” in FIG.

  The left and right drive wheels 2 and 2 are driven by independent electric motors 6 and 6 for traveling. As shown in FIG. 3, the rotation of the electric motor 6 is transmitted to the drive wheel 2 via the speed reducer 7 that is a transmission mechanism and the wheel bearing 4. The electric motor 6, the speed reducer 7, and the wheel bearing 4 constitute an in-wheel motor drive device 8 that is an assembly part. A part or the whole of the in-wheel motor drive device 8 is disposed in the drive wheel 2. Each driving wheel 2 and steered wheel 3 are each provided with a brake (not shown) for decelerating or braking the vehicle.

  As shown in FIG. 1, the steered wheels 3 and 3 serving as left and right front wheels can be steered via a steered mechanism 11 and are steered by a steering mechanism 12. The steered mechanism 11 is a mechanism that changes the angle of the left and right knuckle arms 11b that hold the wheel bearings 5 by moving the tie rods 11a left and right. The tie rod 11a is moved left and right by a steering motor 13 via a rotation / linear motion conversion mechanism (not shown). Between the knuckle arm 11b and the tie rod 11a, a turning angle detecting means 47 for detecting the turning angle is provided. The steering mechanism 12 detects the steering angle of the steering wheel 14 with the steering angle sensor 15, and gives a drive command to the steering motor 13 via the steering control means 34 by a turning command that is the detected steering angle. Steering system (EPS).

  The accelerator input means 16 includes an accelerator pedal and a sensor 16a that detects an amount of depression of the accelerator pedal and outputs an acceleration command (output command). The brake operation means (not shown) includes a brake pedal and a sensor that detects a depression amount of the brake pedal and outputs a deceleration command.

The control system will be described.
In accordance with a main ECU 21 that is an electric control unit for integrated control that controls the entire vehicle, an inverter device 22 that controls the electric motor 6 for each traveling according to a command of the ECU 21, and a braking command output from the ECU 21 A brake controller (not shown) that gives a braking command to the brakes of each drive wheel 2 and each steered wheel 3 is mounted on the vehicle body 1. The ECU 21 includes a computer, a program executed by the computer, various electronic circuits, and the like.

The ECU 21 is roughly classified by function, and controls the drive control unit 21a that performs control related to driving and steering, and other various auxiliary machine systems (for example, an air conditioner, a light, and a wiper), or displays on a display device, for example. It is divided into a general control unit 21b that performs control.
As shown in FIG. 2, the drive control unit 21 a includes basic drive command means 20, and the basic drive command means 20 receives output commands input from the accelerator input means 16, the brake operation means, and the steering angle sensor 15. Accordingly, the motor-specific output command is given to each electric motor 6. Specifically, the basic drive command means 20 is based on the acceleration command output from the accelerator input means 16, the deceleration command output from the brake operation means, and the turning command output from the steering angle sensor 15. The acceleration / deceleration commands given to 6 and 6 are generated as torque command values, distributed to each inverter device 22 via the torque distribution means 33, and output.

  FIG. 3 is a block diagram showing a conceptual configuration of the in-wheel motor drive device and the like of this electric vehicle. As shown in the figure, the inverter device 22 includes a power circuit unit 28 provided for each electric motor 6 and a motor control unit 29 for controlling the power circuit unit 28. The motor control unit 29 outputs information such as detection values and control values regarding the in-wheel motor drive device 8 included in the motor control unit 29 to the ECU 21.

  The power circuit unit 28 includes an inverter 31 that converts DC power of a battery 19 mounted on the vehicle body 1 (FIG. 1) into three-phase AC power used to drive the electric motor 6, and a PWM driver 32 that controls the inverter 31. And have. The electric motor 6 is a three-phase synchronous motor, such as an IPM type (embedded magnet type) synchronous motor. The inverter 31 is composed of a plurality of semiconductor switching elements (not shown), and the PWM driver 32 performs pulse width modulation on the input current command and gives an on / off command to each of the semiconductor switching elements.

  The motor control unit 29 includes a computer, a program executed on the computer, and an electronic circuit. The motor control unit 29 converts it into a current command in accordance with an acceleration / deceleration command based on a torque command value or the like given from the ECU 21 which is the host control means, and gives a current command to the PWM driver 32 of the power circuit unit 28. Further, the motor control unit 29 obtains a motor current value flowing from the inverter 31 to the electric motor 6 from a current sensor that is the current detection means 35 and performs current feedback control. In this current control, the rotation angle of the rotor of the electric motor 6 is obtained from the angle sensor 36, and control according to the rotation angle such as vector control is performed.

  As shown in FIG. 2, the electric vehicle control apparatus A according to this embodiment is an apparatus for controlling the electric vehicle having the above-described configuration, and includes the basic drive command means 20, individual drive system abnormality detection means 23, road surface A road surface friction coefficient estimating means 24 for estimating a friction coefficient, a slip angle estimating means 25 for estimating a slip angle that is a turning angle with respect to the traveling direction of the vehicle in the steered wheels 3 (FIG. 1), and a behavior of the vehicle are estimated. The vehicle behavior estimating means, the abnormal other motor output limiting means 27, the turning angle adjusting means 30, and the steering control means 34 are provided. The drive control unit 21a includes the basic drive command unit 20, the individual drive system abnormality detection unit 23, the road surface friction coefficient estimation unit 24, the slip angle estimation unit 25, the vehicle behavior estimation unit, the other-motor output limitation unit 27 at the time of an abnormality, A steering angle adjusting unit 30 and a steering control unit 34 are provided. The vehicle behavior estimation means is vehicle body bending amount detection means 26 that detects the amount of bending (yaw rate) of the vehicle body 1 (FIG. 1) with respect to the traveling direction of the vehicle as the behavior of the vehicle.

  The individual drive system abnormality detection means 23 detects that an abnormality has occurred in the wheel-by-wheel drive system including the electric motor 6, the speed reducer 7, and the drive wheel 2 for each drive wheel 2 (FIG. 1). For example, when the torque generated in one drive wheel 2 deviates from the torque command value generated by the basic drive command unit 20 of the drive control unit 21a, the individual drive system abnormality detection unit 23 has an abnormality in the drive system for each wheel. Judge that it occurred. The individual drive system abnormality detection means 23, for example, in the wheel-by-wheel drive system, when the relationship between the motor applied voltage and the motor current corresponding to the motor rotation speed is out of the set range, an abnormality has occurred in the wheel-by-wheel drive system. May be detected. Note that the deviation amount of the drive torque at the time of abnormality determination and the setting range are appropriately set by experiments or the like.

  The road surface friction coefficient estimating means 24 calculates the current road surface friction coefficient from the traveling speed of the electric vehicle and the normal driving wheel 2 (FIG. 1) or the rotational speed of the driven wheel. The ECU 21 is provided with a storage means 17 such as a ROM, for example, and the storage means 17 stores the relationship between the traveling speed corresponding to the road surface condition and the rotational speed. The road surface state is, for example, dry or wet, paved road or non-paved road. The road surface friction coefficient estimating means 24 estimates the current road surface friction coefficient by comparing the current traveling speed of the electric vehicle and the rotation speed of the normal drive wheel or driven wheel with the relationship stored in the storage means 17. obtain. The slip angle estimating means 25 detects the slip angle immediately after the occurrence of abnormality from the turning angle detecting means 47.

  When the abnormality is detected by the individual drive system abnormality detection means 23, the other motor output restriction means 27 at the time of abnormality is restricted to the output of the electric motor 6 of the other wheel drive system. Add The abnormal-time other motor output limiting means 27 includes a determination unit 27a and a limiting unit 27b. The determination unit 27a, for example, includes a road surface friction coefficient estimated by the road surface friction coefficient estimation unit 24, a slip angle estimated by the slip angle estimation unit 25, and a vehicle body bending amount detected by the vehicle body bending amount detection unit 26. From this, the wear amount of the steered wheels is calculated, and it is determined whether or not the wear amount is equal to or greater than a predetermined threshold value.

  The threshold value is determined based on, for example, the amount of wear that causes the tire of the steered wheels to run in a state in which the tire of the steered wheels cannot travel when an abnormality occurs in the drive system for each wheel by testing or simulation. For example, when an abnormality occurs in the drive system for each wheel in a test or simulation, for example, an abnormal state is forcibly created by not giving a torque command value that should be given to the electric motor 6 of one wheel drive system. . When calculating the wear amount of the steered wheels, it is assumed that the tire tread depth of the steered wheels does not exceed a predetermined use limit, that is, the tire is not worn beyond the use limit.

When restricting the output of the electric motor 6 that is not detected as abnormal, the restricting unit 27b restricts either or both of an upper limit value and a lower limit value of the output.
The effect when the lower limit value of the output of the electric motor 6 is limited will be described. For example, when an unintended running resistance occurs due to, for example, the motor being fixed, the torque lower limit value of the normal motor is increased, so that a slight accelerator operation is performed. In contrast, effects such as allowing the vehicle to move can be obtained.
In these cases, the output of the electric motor 6 to be limited is torque. When the abnormality occurs in any one of the wheel drive systems, the restricting unit 27b is configured such that, for example, each drive wheel 2 and each steered wheel 3 do not burst as a load of a component necessary for driving force transmission. However, the output of the electric motor 6 may be uniquely limited to a predetermined limit value based on the distance and vehicle speed at which the vehicle can travel by itself.

  In addition, when the electric vehicle includes a navigation system that guides the route to the set destination and calculates the distance, the limiting unit 27b outputs the output of the electric motor 6 that is not detected as abnormal as follows. It may be limited as follows. The navigation system has destination setting means for setting a route that is a recommended route from the current location or an arbitrary point to the destination. For example, the limiting unit 27b may determine a limit value of the output of the electric motor 6 according to the distance along the route to the destination set in the destination setting means.

  When the route to the destination is already set in the navigation system and the electric vehicle is driven along the route, the restricting unit 27b takes the route from the point where the abnormality occurs in one wheel drive system to the destination. The limit value of the output of the electric motor 6 may be determined according to the distance along. When the route to the destination is not set in the navigation system, when an abnormality occurs in one of the wheel drive systems, for example, the general control unit 21b displays that the abnormality has occurred on the display device, and Call attention to vehicle occupants. Thus, the occupant can arbitrarily set a route from the current location to a destination such as a repair shop in the navigation system. Thereafter, the limiter 27b may determine a limit value of the output of the electric motor 6 according to the distance along the route from the current location to the destination.

The limit value of the output of the electric motor 6 may be determined according to the amount of power of the battery 19 to reach the destination from the current location or an arbitrary point.
The limiter 27b sets the limit value of the output of the electric motor 6 according to at least one of the distance to the destination, the load of the components necessary for transmitting the driving force, and the amount of electric power required to reach the destination. You may decide.

FIG. 4A is a block diagram schematically showing the configuration of an electric vehicle when both the wheel drive systems are normal, and FIG. 4B is an operation explanatory diagram when one of the wheel drive systems is abnormal. is there. This will be described with reference to FIG.
As shown in FIGS. 2 and 4B, when the turning angle adjusting means 30 detects that an abnormality has occurred in one of the wheel drive systems by the individual drive system abnormality detection means 23, the abnormality is detected. The vehicle body bend amount detected by the vehicle body bend amount detecting means 26 before occurrence and the vehicle body bend amount detected by the vehicle body bend amount detecting means 26 after an abnormality has occurred are not changed. This means is capable of adjusting the turning angle of the steering wheels 2 and 2.

  In FIG. 4A, the electric vehicle is traveling straight, for example, when both the drive systems for each wheel are normal. As shown in FIG. 4B, when an abnormality occurs in one wheel drive system and the electric vehicle is driven by the other wheel drive system, a yaw moment 37 is generated around the center of gravity of the electric vehicle. In this case, since the electric vehicle tends to turn undesirably, the turning angle adjusting means 30 generates the yaw moment 38 in the reverse direction by the turning mechanism 11. The turning angle adjusting means 30 performs control to generate a reverse yaw moment 38 that cancels the yaw moment 37 via the steering control means 34 in response to the abnormality detection by the individual drive system abnormality detecting means 23. Therefore, the electric vehicle can maintain a straight traveling state without any change in the amount of vehicle body bending before and after the occurrence of an abnormality. In this example, the electric vehicle is in a straight traveling state, but the turning angle adjusting means 30 can maintain a desired turning state before and after the occurrence of an abnormality even in a turning state.

FIG. 5 is a flowchart showing an example of limiting the output of the electric motor of the electric vehicle control device. This will be described with reference to FIG. The aforementioned individual drive system abnormality detection means 23 performs the process of step S1 in FIG. 5, and the road surface friction coefficient estimation means 24 and the slip angle estimation means 25 perform the process of step S2, and the determination of the other motor output restriction means 27 in the event of an abnormality. The unit 27a performs steps S3 and S4. The limiting unit 27b of the other motor output limiting means 27 at the time of abnormality performs the process of step S5.
For example, this processing is started by turning on an ignition switch or the like of the vehicle. After the start of this process, the individual drive system abnormality detection means 23 always detects whether or not an abnormality has occurred in the drive system for each wheel (step S1). When no abnormality has occurred in any of the drive systems for each wheel (step S1: no), the basic drive command means 20 distributes the motor to the electric motor 6 in accordance with the output command input from the accelerator input means 16. Give another output command. As a result, the electric vehicle can normally travel.

  When it is detected that an abnormality has occurred in any one of the drive systems for each wheel (step S1: yes), the road surface friction coefficient estimating means 24 estimates the friction coefficient of the road surface, and the slip angle estimating means 25 estimates the slip angle. (Step S2). Next, the determination unit 27a of the abnormal motor output limiting means 27 calculates the wheel load (the amount of wear of the steered wheels in this example) (step S3), and determines whether or not the wheel load is equal to or greater than a threshold value (step S3). S4). When the wheel load is less than the threshold value (step S4: no), the process returns to step S1. When the wheel load is equal to or greater than the threshold (step S4: yes), the limiting unit 27b of the other motor output limiting means 27 at the time of abnormality limits the output of the electric motor 6 of the normal wheel drive system (step S5). Thereafter, the process returns to step S1.

The effect will be described.
When the individual drive system abnormality detecting means 23 detects that an abnormality has occurred in the drive system for each wheel, the other motor output limiting means 27 at the time of abnormality is a normal wheel with respect to the output command given by the basic drive command means 20. Limit the output of the electric motor 6 of each drive system. The abnormal-time other motor output limiting means 27 calculates a load necessary for traveling of the electric vehicle, and limits the output of the electric motor 6 according to a predetermined rule. Thus, even when an abnormality occurs in the drive system for each wheel, by calculating the load necessary for traveling on the electric vehicle, the electric vehicle can be more reliably self-propelled to a desired destination.

The abnormal-time other motor output limiting means 27 is a road surface friction coefficient estimated by the road surface friction coefficient estimating means 24, a slip angle estimated by the slip angle estimating means 25, and a vehicle body bending amount detecting means 26. The amount of wear of the steered wheels 3 is calculated from the amount of the bend, and when the amount of wear is equal to or greater than a predetermined threshold, the output of the electric motor 6 of the normal drive system for each wheel is limited. Thus, by calculating the amount of wear of the steered wheels 3 and comparing it with the threshold value, the output of the electric motor 6 can be more accurately limited.
The steered angle adjusting means 30 adjusts the steered angle of the steered wheels 3 so that the yaw moment in the opposite direction is offset with respect to the yaw moment generated when one of the wheel drive systems is abnormal. Thereby, the traveling state of the vehicle can be maintained so that there is no change in the traveling direction of the vehicle before and after the occurrence of the abnormality.

Another embodiment will be described.
In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  FIG. 6 is a block diagram illustrating a conceptual configuration of a main part of an electric vehicle control device according to another embodiment. The electric vehicle control device may include a current detection unit 35 that detects a current value that flows through the electric motor 6 of a normal wheel drive system, and a temperature detection unit 49 that detects the temperature of the normal electric motor 6. . When the temperature detected by the temperature detecting means 49 is equal to or greater than a predetermined threshold, the other motor output limiting means 27 at the time of abnormality is such that the current value detected by the current detecting means 35 is less than or equal to the predetermined current value. In addition, the output of the electric motor 6 of a normal wheel drive system may be limited. The threshold value is determined based on the motor temperature when demagnetization occurs in the permanent magnet of the electric motor 6 of the other wheel drive system that is normal, for example, when the wheel drive system is abnormal by testing or simulation.

  FIG. 7 is a flowchart showing an example of limiting the output of the electric motor of the electric vehicle control device. This will be described with reference to FIG. The individual drive system abnormality detection means 23 performs the process of step a1 in FIG. 7, and the current detection means 35 and the abnormal other motor output restriction means 27 perform the process of step a2, and the temperature detection means 49 and the abnormal other motor output restriction. The means 27 performs step a3. The determination unit 27a performs the process of step a4, and the restriction unit 27b performs the process of step a5.

When it is detected that an abnormality has occurred in any one of the drive systems for each wheel (step a1: yes), the other-motor output limiting means 27 at the time of abnormality outputs a current value to be supplied to the electric motor 6 of the normal wheel drive system. Obtained from the detection means 35. Further, the abnormal motor output limiting means 27 obtains the normal temperature of the electric motor 6 from the temperature detecting means 49. Next, the determination unit 27a determines whether or not the temperature detected by the temperature detection unit 49 is equal to or higher than a predetermined threshold (step a4). When the temperature is lower than the threshold value (step a4: no), the process returns to step a1. When the temperature is equal to or higher than the threshold (step a4: yes), the limiting unit 27b limits the output of the electric motor 6 of the normal wheel drive system (step a5). Thereafter, the process returns to step a1.
By limiting the output of the electric motor 6 in this way, for example, the electric vehicle is undesirably stopped due to demagnetization of the permanent magnet of the electric motor 6 during traveling to a destination such as a repair shop. Can be avoided.

You may make it transmit rotation of the electric motor 6 to a wheel via the wheel bearing 4 without interposing the reduction gear 7. In this case, a transmission shaft (not shown) rotatably supported by the wheel bearing corresponds to the “transmission mechanism” of the present application.
The electric vehicle control device can be applied to, for example, an electric vehicle in which two front wheels are individually motor-driven, or an electric vehicle in which four front and rear wheels are individually motor-driven. The electric vehicle control device can also be applied to a hybrid vehicle.

DESCRIPTION OF SYMBOLS 1 ... Car body 2 ... Drive wheel 4 ... Wheel bearing 6 ... Electric motor 7 ... Reduction gear (transmission mechanism)
8 ... In-wheel motor drive device 16 ... Accelerator input means 20 ... Basic drive command means 23 ... Individual drive system abnormality detection means 24 ... Road surface friction coefficient estimation means 25 ... Slip angle estimation means 26 ... Car body bend amount detection means 27 ... Abnormality Other motor output limiting means 30 ... turning angle adjusting means 35 ... current detecting means 49 ... temperature detecting means

Claims (6)

In an electric vehicle control device that controls an electric vehicle including a plurality of electric motors that respectively drive a pair of left and right driving wheels, and a transmission mechanism that transmits a driving force from the electric motors to the driving wheels.
Basic drive command means that distributes to the electric motor according to the output command input from the accelerator input means and gives an output command for each motor;
Individual drive system abnormality detection means for detecting that an abnormality has occurred in the wheel-by-wheel drive system comprising the electric motor for each drive wheel, the transmission mechanism, and the drive wheel;
When it is detected by the individual drive system abnormality detection means that an abnormality has occurred in one of the wheel drive systems, the other motor output limit is set to limit the output of the electric motor of the other wheel drive system. Means and
The abnormal-motor other-motor output limiting means calculates a load necessary for traveling of the electric vehicle and limits the output of the electric motor according to a predetermined rule. In the electric vehicle control device according to claim 1,
Road surface friction coefficient estimating means for estimating the friction coefficient of the road surface;
Slip angle estimating means for estimating a slip angle which is a steered angle with respect to the traveling direction of the vehicle in steered wheels;
Vehicle body bend amount detecting means for detecting the amount of bend of the vehicle body with respect to the traveling direction of the vehicle;
Provided,
The abnormal-time other motor output limiting means includes a road surface friction coefficient estimated by the road surface friction coefficient estimation means, a slip angle estimated by the slip angle estimation means, and a vehicle body detected by the vehicle body bending amount detection means. An electric vehicle control device that calculates the amount of wear of the steered wheels from the amount of bending and restricts the output of the electric motor of the other wheel-by-wheel drive system when the amount of wear is equal to or greater than a predetermined threshold. In the electric vehicle control device according to claim 1 or 2,
Current detection means for detecting a current value flowing to the electric motor of the other wheel-by-wheel drive system;
Temperature detecting means for detecting the temperature of the electric motor;
Provided,
When the temperature detected by the temperature detecting means is equal to or higher than a predetermined threshold, the other motor output limiting means at the time of abnormality is such that the current value detected by the current detecting means is not more than a predetermined current value. The electric vehicle control apparatus which restrict | limits the output of the said electric motor of the other wheel-by-wheel drive system.   4. The electric vehicle control device according to claim 1, wherein a speed reducer is provided as the transmission mechanism, the wheel-by-wheel drive system includes a wheel bearing that supports the drive wheel, and the electric drive device. The electric vehicle control apparatus which comprises an in-wheel motor drive device with the motor and the said reduction gear which transmits the drive of this electric motor to the said wheel bearing.   5. The electric vehicle control device according to claim 1, further comprising vehicle behavior estimation means for estimating the behavior of the vehicle, wherein the one of the wheels is detected by the individual drive system abnormality detection means. When it is detected that an abnormality has occurred in the drive system, the behavior of the vehicle estimated by the vehicle behavior estimation means before the occurrence of the abnormality and the vehicle behavior estimation means after the abnormality has occurred are estimated. An electric vehicle control device provided with a turning angle adjusting means capable of adjusting a turning angle of a turning wheel of the electric vehicle so that the behavior of the vehicle does not change.   6. The electric vehicle control device according to claim 5, wherein the vehicle behavior estimating means is a vehicle body bending amount detecting means for detecting a vehicle body bending amount with respect to a traveling direction of the vehicle as the vehicle behavior.

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