JP5359664B2 - Control device for four-wheel independent drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a four-wheel independent drive vehicle that allows continuous stable traveling even while a failure occurs in any one of in-wheel motors and an output torque of the failed in-wheel motor is reduced. <P>SOLUTION: The control device for a four-wheel independent drive vehicle includes a motor having a powering function and a regeneration function respectively as a drive power source, and a brake device for braking wheels by a frictional force, thereby independently controlling each torque of front/rear and right/left four wheels. The control device includes a fail-safe means (steps S3, S5) that limits the total drive torque of the whole vehicle if the motor is subjected to powering control when a failure occurs in any one wheel of the four wheels, and maintains the total braking torque of the whole vehicle in a normal state that the failure does not occur if the motor is subjected to regenerative control. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a control device for a four-wheel independent drive vehicle that uses an electric motor as a driving force source and can independently control the torques of the front, rear, left and right four wheels.

  2. Description of the Related Art In recent years, a so-called in-wheel motor type vehicle has been developed as an embodiment of an electric vehicle in which an electric motor is disposed in or near the wheel of the wheel and the wheel is directly driven by the electric motor. In this in-wheel motor type vehicle, the driving torque or braking torque applied to each driving wheel can be individually controlled by individually performing power running control or regenerative control on the motor provided for each wheel (driving wheel). Can do. That is, a four-wheel independent drive vehicle using an electric motor as a driving force source can be configured. Further, since the electric motor is provided in or near the wheel of the driving wheel and directly transmits power to the driving wheel, it is necessary to provide a power transmission mechanism such as a transmission or a differential provided in a conventional vehicle. Thus, the configuration of the vehicle can be simplified.

  When an electric motor is used as a driving force source of a vehicle, such as an electric vehicle including an in-wheel motor type vehicle as described above, or a hybrid vehicle, the electric motor normally has characteristics such as rated torque, rated speed, or temperature rise as the use limit. The operation is controlled in consideration of the above. In connection with this, Patent Document 1 discloses an example of a vehicle using an electric motor as a driving force source for the purpose of preventing overheating due to overload operation of a motor. The electric vehicle described in Patent Document 1 is a vehicle equipped with a motor driving device that executes torque limitation when the motor temperature is higher than a predetermined temperature, and can generate vehicle driving force by the power running torque of the motor. It is configured as follows. In particular, when a braking mechanism for generating the braking force of the vehicle is further provided, when the power running torque is generated when the motor regenerative torque is generated with respect to the motor output torque in a region where the motor temperature is higher than a predetermined temperature. It is configured to apply relatively stricter restrictions than the above.

  In Patent Document 2, at least one of the front and rear wheels is driven by two motors for the purpose of ensuring straight running stability and cornering stability when the motor or brake system is abnormal. A torque distribution control device for a vehicle configured to control torque distribution to the left and right wheels according to a torque output command to both motors, and in particular, only one of the left and right wheels is abnormal and excessive. There is described a vehicle torque distribution control device configured to offset a torque distribution value to a normal wheel side or limit an output of a motor that drives an abnormal wheel when it is determined that the rotation is abnormal.

  Patent Document 3 discloses, for example, a motor as a drive source for the purpose of enabling travel and ensuring safety when some of the wheels of the independent drive system vehicle cannot be driven during travel. The target driving force for each wheel is corrected so that the ratio of the total driving force of the left wheel and the total driving force of the right wheel is the same when the vehicle is normal and when it cannot be driven. A driving force control device for a wheel independent drive type vehicle configured as described above is described.

JP 2007-244072 A JP 2006-256454 A JP 2005-119647 A

  In the vehicle described in Patent Document 1, when the motor temperature is higher than a predetermined temperature, the output torque of the motor is limited, so that the temperature rise of the motor is suppressed, and thus overheating of the motor is prevented. can do. For example, the temperature rise of the motor can be suppressed by reducing the driving torque generated by power running control of the motor during driving, or by reducing the braking torque generated by regenerative control of the motor during braking.

  The configuration for preventing overheating due to overload operation of the motor described in Patent Document 1 can also be applied to the control of the above-described four-wheel independent drive vehicle of the in-wheel motor system. For example, when a failure occurs in which the temperature of an in-wheel motor of any one of four-wheel independent drive vehicles becomes higher than a predetermined temperature, the output torque of the in-wheel motor in which the failure has occurred is limited. As a result, temperature rise can be suppressed and damage due to overheating can be prevented.

  However, since the output torque of the motor that failed during traveling is limited, the driving force or braking force necessary for stable traveling is insufficient, or the balance of the driving torque or braking torque of the four wheels is deteriorated. May be disturbed. Further, when the failed motor is supplemented with another normal motor, the normal motor may be overloaded. Thus, in the four-wheel independent drive vehicle as described above, from the viewpoint of fail-safe, in order to continue traveling under stable vehicle behavior even when a failure occurs in the motor of any wheel. There was still room for improvement.

  The present invention has been made paying attention to the above technical problem, and even in a situation where a failure occurs in any one of the electric motors that drive each wheel, and the output torque thereof is reduced, it is stable. An object of the present invention is to provide a control device for a four-wheel independent drive vehicle capable of continuing traveling.

In order to achieve the above object, the invention of claim 1 includes an electric motor having a power running function and a regenerative function as a driving force source, and a brake device that brakes the wheel by frictional force. In the control device for a four-wheel independent drive vehicle capable of independently controlling the torque, when the motor is subjected to power running control when a failure occurs in any one of the four wheels, the total drive of the entire vehicle when limiting the torque, when said electric motor is regenerative control is a means that maintain the total braking torque of the whole vehicle in a normal state where the fail does not occur, to limit the total drive torque, The drive output by the motor of the wheel that limits the drive torque output by the motor of the wheel in which the failure has occurred and does not have the failure on the side in which the failure has occurred in the left-right direction. When the motor is regeneratively controlled, the braking torque output by the motor of the wheel in which the failure has occurred is limited, and the motor of the wheel in which the failure on the side where the failure has occurred does not occur. it is a control device according to claim which has the full Eirusefu means for applying a braking torque by the brake device for the wheel braking torque increased thereby and the fail to occur to be output.

Further, the invention of claim 2 is the side of the invention of claim 1 , wherein the fail safe means is a side where no fail occurs in the left-right direction when the electric motor is power-running controlled and the required driving force is relatively small. And a means for increasing the driving torque of the wheel facing the wheel in which the failure has occurred in the front-rear direction to be larger than the driving torque of the wheel facing the wheel in which the failure has occurred in the left-right direction. Device.

According to a third aspect of the present invention, in the first aspect of the present invention, when the fail-safe means fails in the left or right front wheel, the electric motor is controlled for power running and the required driving force is relative. The driving torque of the front wheel on the side where the failure does not occur is larger than the driving torque of the rear wheel on the side where the failure does not occur, the motor is regeneratively controlled, and the required braking force is relatively In the case where it is large, the control device includes means for making the braking torque of the front wheel on the side where the failure does not occur larger than the braking torque of the rear wheel on the side where the failure does not occur.

According to a fourth aspect of the present invention, in the first aspect of the present invention, when the fail safe means performs power running control when the failure occurs in the left or right front wheel, the fail The control device includes means for outputting the driving torque of the front wheel on the non-occurring side before the rear wheel on the non-failing side.

According to a fifth aspect of the present invention, in the first aspect of the present invention, when the fail safe means is regeneratively controlled and the required braking force is relatively small, a failure on the side where the failure occurs occurs. The control device includes a means for restricting the braking torque of a wheel that has not been braked and for relatively speeding up the time when the wheel in which the failure has occurred is braked by the brake device.

The invention of claim 6 is the invention according to any one of claims 1 to 5 , wherein the electric motor is provided in or near the wheel of each of the four wheels, and transmits power directly to each of the four wheels. The control device includes an in-wheel motor that applies torque.

  According to the first aspect of the present invention, when a failure occurs in any one of the four wheels, when the motor is subjected to power running control, that is, when the motor outputs a drive torque, as a drive force source of the vehicle The total drive torque that is all the drive torque output by the electric motor is limited. Therefore, it is possible to prevent an overload on the electric motor that causes drive torque to act on the other three wheels where no failure has occurred, and to ensure a stable driving force of the vehicle by these normal three wheels. When the motor is regeneratively controlled, that is, when the motor outputs braking torque, the total braking torque, which is all braking torque output by the motor as a driving force source for the vehicle, is maintained in a state before the failure occurs. . Therefore, the braking force of the vehicle can be secured stably.

In addition , when the total driving torque is limited, the output of the electric motor that causes the driving torque to act on the wheel in which the failure has occurred is limited, and the same side in the left-right direction (or width direction) of the vehicle in which the failure has occurred The output of the electric motor that causes the drive torque to act on the wheel that has not failed is increased. Therefore, the total driving torque can be limited without disturbing the balance of driving forces in the left-right direction of the vehicle. When the electric motor is regeneratively controlled, the output of the electric motor that applies braking torque to the wheel in which the failure has occurred is limited, and no failure has occurred on the same side in the left-right direction of the vehicle in which the failure has occurred. The output of the electric motor that applies the braking torque to the wheel is increased, and the braking torque is applied to the wheel that has failed by the brake device. Therefore, the total braking torque can be maintained without disturbing the balance of the braking force in the left-right direction of the vehicle. In addition, the amount of power generated by a normal motor during regeneration can be increased by increasing the output of the motor that causes braking torque to act on wheels that have not failed.

According to the invention of claim 2 , for example, when a failure occurs in one of the left and right front wheels and the required driving force is relatively small, the driving torque of the other front wheel is reduced, and the other, The driving torque of the rear wheels on the side where no failure occurs is increased, and the front and rear driving torque distribution of the vehicle is set to the state of “front wheels <rear wheels”. On the other hand, if a failure occurs on one of the left and right rear wheels and the required driving force is relatively small, the driving torque of the other rear wheel is reduced and the other, ie, the side where no failure occurs. The driving torque of the front wheels is increased, and the driving torque distribution in the front and rear of the vehicle is set to the state of “front wheels> rear wheels”. Therefore, even when any one of the wheels fails, the vehicle can be stably driven in the form of rear wheel drive or front wheel drive.

According to the invention of claim 3, when a failure occurs in one of the left and right front wheels and the required driving force or the required braking force is relatively large, the driving torque or braking torque of the other front wheel is That is, it is made larger than the rear wheel on the side where no failure occurs. For this reason, it is possible to increase the torque distribution of the front wheels that have good cooling efficiency during traveling and a large thermal rated torque, and extend the travelable time.

According to the fourth aspect of the present invention, when a failure occurs in one of the left and right front wheels, the driving torque of the other front wheel is output before the other rear wheel, that is, the side where no failure occurs. Is done. Therefore, it is possible to detect information on the friction coefficient of the traveling road surface with the front wheels of the vehicle, and appropriately control the driving torque of the rear wheels based on the information.

Further, according to the invention of claim 5, if a failure occurs in either the left or right wheel and the required braking force is relatively small, the braking torque of the normal wheel on the side where the failure occurs is limited, Braking by the brake device for the failed wheel is performed at an early stage. Therefore, the regenerative power generation by the normal wheel motor on the side where the failure occurs can be executed as effectively as possible.

According to the sixth aspect of the present invention, the in-wheel motor is mounted as an electric motor that applies driving torque or braking torque independently for each of the four wheels. Therefore, the driving force or braking force of the vehicle can be easily generated independently on the front and rear wheels.

It is a flowchart for demonstrating the basic flow of the fail safe control by the control apparatus of this invention. It is a conceptual diagram for demonstrating 1st Example of the fail safe control by the control apparatus of this invention, Comprising: It is the map applied in the 1st Example. It is a conceptual diagram for demonstrating 2nd Example of the fail safe control by the control apparatus of this invention, Comprising: It is the map applied in the 2nd Example. It is a conceptual diagram for demonstrating 3rd Example of the fail safe control by the control apparatus of this invention, Comprising: It is the map applied in the 3rd Example. It is a conceptual diagram for demonstrating 4th Example of the fail safe control by the control apparatus of this invention, Comprising: It is the map applied in the 4th Example. It is a conceptual diagram for demonstrating 5th Example of the fail safe control by the control apparatus of this invention, Comprising: It is the map applied in the 5th Example. It is a conceptual diagram for demonstrating 6th Example of the fail safe control by the control apparatus of this invention, Comprising: It is the map applied in the 6th Example. It is a conceptual diagram for demonstrating the example of the fail safe control by a prior art. It is a figure which shows typically the structure of the four-wheel independent drive vehicle made into the object of control by this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. First, FIG. 9 shows the configuration and control system of a four-wheel independent drive vehicle Ve that is a subject of the present invention. The vehicle Ve shown in FIG. 9 has left and right front wheels 1 and 2 and left and right rear wheels 3 and 4 in the width direction of the vehicle. The front wheels 1 and 2 are supported on the vehicle body Bo of the vehicle Ve via a suspension mechanism (not shown) or the like independently of each other. Similarly, the rear wheels 3 and 4 are also mutually independent or independent of each other. Then, it is supported by the vehicle body Bo of the vehicle Ve via a suspension mechanism (not shown) or the like.

  Electric motors 5 and 6 are incorporated in the front wheels 1 and 2, and electric motors 7 and 8 are incorporated in the rear wheels 3 and 4, respectively. It is connected so that power can be transmitted. That is, the electric motors 5 and 6 of the front wheels 1 and 2 and the electric motors 7 and 8 of the rear wheels 3 and 4 are so-called in-wheel motors 5, 6, 7 and 8, together with the front wheels 1 and 2 and the rear wheels 3 and 4. It is arranged under the spring of the vehicle Ve. Then, by independently controlling the rotation of the in-wheel motors 5, 6, 7, and 8, the driving torque or braking torque of the front wheels 1 and 2 and the rear wheels 3 and 4 can be independently controlled. It can be done.

  Each of these in-wheel motors 5, 6, 7, and 8 is configured by an AC synchronous motor, for example, and is connected to a power storage device 10 such as a battery or a capacitor via an inverter 9. Therefore, when the in-wheel motors 5, 6, 7, and 8 are driven, the DC power of the power storage device 10 is converted into AC power by the inverter 9, and the AC power is supplied to the in-wheel motors 5, 6, 7, and 8. As a result, the in-wheel motors 5, 6, 7, 8 are subjected to power running control, and driving torque is applied to the front wheels 1, 2 and the rear wheels 3, 4. The in-wheel motors 5, 6, 7, 8 can be regeneratively controlled using the rotational energy of the front wheels 1, 2 and the rear wheels 3, 4. That is, at the time of regeneration / power generation of the in-wheel motors 5, 6, 7, 8, the rotational (kinetic) energy of the front wheels 1, 2 and the rear wheels 3, 4 is converted into electric energy by the in-wheel motors 5, 6, 7, 8. The electric power generated at that time is stored in the power storage device 10 via the inverter 9. At this time, braking torque based on regenerative / generated power is applied to the front wheels 1 and 2 and the rear wheels 3 and 4.

  Brake devices 11, 12, 13, and 14 are respectively provided between the wheels 1, 2, 3, and 4 and the in-wheel motors 5, 6, 7, and 8 that are linked to the wheels. Each of the brake devices 11, 12, 13, and 14 is a known brake device that brakes a wheel by using a frictional force such as a disc brake or a drum brake. For example, the various brake devices are appropriately selected. is set up. These brake devices 11, 12, 13, 14 are, for example, brake caliper pistons that generate braking force on the wheels 1, 2, 3, 4 by hydraulic pressure pumped from a master cylinder (not shown). (Not shown) or a brake actuator (not shown) is connected to a brake actuator 15 that operates.

  A steering device 16 is provided between the front wheels 1 and 2. The steering device 16 in the vehicle Ve is configured to be steered by a steering operation by a driver and to be capable of automatic steering based on a control signal from an electronic control device 17 described later.

  The inverter 9 and the brake actuator 15 are respectively connected to an electronic control unit (ECU) 17 that controls the rotation state of each in-wheel motor 5, 6, 7, 8 or the operation state of the brake actuator 15.

  The electronic control unit 17 includes, for example, an accelerator sensor (or an accelerator switch) 18 that detects a driver's accelerator operation amount from an accelerator pedal depression amount (or angle, pressure), etc., a brake pedal depression amount (or angle, A brake sensor (or a brake switch) 19 that detects the amount of brake operation by the driver from the pressure), a vehicle speed sensor 20 that detects the vehicle speed based on the number of rotations of each wheel 1, 2, 3, 4, and each in-wheel motor 5 , 6, 7, 8, detection signals from various sensors such as a motor temperature sensor 21, and an information signal from the inverter 9 are input.

  Of these, the required driving force or the required braking force corresponding to the driver's accelerator operation amount and brake operation amount is calculated and obtained based on signals input from the accelerator sensor 18 and the brake sensor 19. Further, the output torques (motor torques) of the in-wheel motors 5, 6, 7, and 8 are calculated and obtained based on the signal input from the inverter 9. For example, when it is detected from the input signal from the inverter 9 that the in-wheel motors 5, 6, 7, and 8 are controlled in power running, the power is supplied to the in-wheel motors 5, 6, 7, and 8 at that time. The amount of electric power or the current value to be detected can be detected, and the motor torques of the in-wheel motors 5, 6, 7 and 8 can be calculated based on the detected electric energy or current value.

  On the other hand, from the electronic control unit 17, a signal for controlling the rotation of each in-wheel motor 5, 6, 7, 8 via the inverter 9, and each brake device 11, 12, 13 via the brake actuator 15. , 14, a signal for controlling the operation of the steering device 16, a signal for controlling the operation of the steering device 16, and the like.

  As described above, the vehicle Ve targeted by the present invention is provided with the in-wheel motors 5, 6, 7, and 8 for each of the four wheels 1, 2, 3, and 4 on the front, rear, left, and right sides. The torque of 1, 2, 3 and 4 can be controlled independently. Therefore, for example, a failure occurs in any one of the in-wheel motors 5, 6, 7, 8 during traveling, or any one of the wheels 1, 2, 3, 4 and the in-wheel motor 5, 6, 6. Even if a desired drive torque or braking torque cannot be obtained with any one of the wheels 1, 2, 3, 4 due to a failure in the transmission mechanism between the motors 7, 8, etc. The vehicle Ve can be continuously driven by controlling the torques of the three normal wheels.

  However, in that case, it is necessary to consider the characteristics of each in-wheel motor 5, 6, 7, 8, such as the rise in temperature, and the torque of the front / rear or left / right torque from the viewpoint of running stability of the vehicle Ve. It is necessary to consider the balance. Therefore, in the control device for the vehicle Ve according to the present invention, even when a failure occurs in any one of the wheels or in the in-wheel motor that drives the wheels, it is possible to continue stable traveling, that is, so-called The fail safe control shown below is performed so that the fail safe can be established.

  FIG. 1 is a flowchart for explaining the basic flow of the fail-safe control. The routine shown in this flowchart is repeatedly executed every predetermined short time. That is, the fail-safe control according to the present invention is the rotation control of the driving force source when a failure occurs in any one of the wheels 1, 2, 3, 4 or the in-wheel motors 5, 6, 7, 8. The content of the fail safe control is appropriately changed depending on whether the state is power running control or regenerative control.

  Specifically, in FIG. 1, first, it is determined whether or not a failure has occurred in each of the wheels 1, 2, 3, 4 or in-wheel motors 5, 6, 7, 8 linked thereto. Determination is made (step S1). In the present invention, for example, a failure occurs in any one of the in-wheel motors 5, 6, 7, 8, or each in-wheel motor 5, 6, 7, 8 and each wheel 1, 2. , 3, 4, any one of the transmission mechanisms, etc., some kind of abnormality has occurred, and it is no longer possible to generate the desired driving force or braking force at the wheel where the abnormality has occurred . Therefore, for example, signals and current values for controlling the in-wheel motors 5, 6, 7, and 8 are monitored, or the wheels 1, 2, 3, and 4 and the in-wheel motors 5, 6, 7, and 8 are monitored. The occurrence of a failure can be detected by monitoring the differential rotational speed.

  If the occurrence of a failure is not detected and a negative determination is made in step S1, there is no need to execute fail-safe control, so this routine is temporarily terminated without executing the subsequent control. If affirmative determination is made in step S1 because the occurrence of a failure is detected, the process proceeds to step S2, and the rotational control state of the driving force source, that is, each of the in-wheel motors 5, 6, 7, 8 is determined. It is determined whether or not the power running control is performed.

  When the rotational control state of each in-wheel motor 5, 6, 7 and 8 is power running control, when affirmative determination is made in step S2, that is, each in-wheel motor 5, 6, 7, 8 is When the driving torque for generating the driving force is output from each of the wheels 1, 2, 3, and 4, the process proceeds to step S3, and the fail-safe control during powering, that is, each of the wheels 1, 2, 3, and 4 is output. Alternatively, when any one of the in-wheel motors 5, 6, 7, 8 linked to them fails, the in-wheel motors 5, 6, 7, 8 are subjected to power running control. Torque control of the in-wheel motors 5, 6, 7, and 8 is executed so as to limit the total drive torque that is the sum of the drive torques of the wheels 1, 2, 3, and 4 with respect to the required drive force of the entire Ve. Details of the fail safe control during power running will be described later together with details of the fail safe control during regeneration.

  On the other hand, if the rotation control state of each in-wheel motor 5, 6, 7, 8 is not power running control, if a negative determination is made in step S2, the process proceeds to step S4, where each in-wheel motor 5, 6 , 7 and 8 are judged whether or not the rotation control state is the regenerative control. If the rotation control state of each in-wheel motor 5, 6, 7, 8 is not regenerative control, and if a negative determination is made in step S4, this routine is temporarily terminated without executing the subsequent control.

  And when the rotation control state of each in-wheel motor 5,6,7,8 is regenerative control and it is judged affirmatively by step S4, it progresses to step S5, ie, the fail safe control at the time of regeneration, ie, When each wheel 1, 2, 3, 4 or any one of the in-wheel motors 5, 6, 7, 8 linked thereto fails, each in-wheel motor 5, 6, 7, 8 Is regeneratively controlled, the total braking torque, which is the sum of the braking torques of the wheels 1, 2, 3, and 4 with respect to the required braking force of the entire vehicle Ve, is maintained in a normal state before the failure occurs. Thus, torque control of each in-wheel motor 5,6,7,8 is performed.

  As described above, when the fail-safe control during power running or the fail-safe control during regeneration is executed in step S3 or step S5, this routine is once ended.

(First control example)
Next, a specific example of fail safe control during power running will be described as a first control example in the present invention. This first control example is a basic example of fail-safe control during power running, and is executed based on the control map of each in-wheel motor 5, 6, 7, 8 shown in FIG. This control map of FIG. 2 shows that when any one in-wheel motor (in this embodiment, the in-wheel motor 6 on the right side of the front wheel) fails, the remaining three in-wheel motors (that is, each in this embodiment) This is for controlling the driving torque of the in-wheel motors 5, 7, 8).

  Specifically, the control map of FIG. 2 includes a total driving torque that is a sum of driving torques acting on the wheels 1, 2, 3, and 4 for a predetermined required driving force, and the wheels 1, 2, and 4. The torque distribution or the torque sharing rate of each of 3 and 4 is shown. In each control map described below including FIG. 2, T1 indicates the allowable maximum torque (rated torque) of each in-wheel motor 5, 6, 7, 8 alone, and T2 indicates each in-wheel motor. The thermal rated torque is preferably set to the upper limit when the temperature rise of 5, 6, 7, 8 is considered.

  In the control map of FIG. 2, the distance between the broken line L0 at the predetermined accelerator opening, that is, the required driving force, and the horizontal axis representing the accelerator opening is the total in the normal state where no failure occurs in any in-wheel motor. The driving torque, that is, the sum of the maximum driving torque that can be output in the range of the allowable maximum torque by each of the in-wheel motors 5, 6, 7, and 8 is represented. Therefore, the distance between the broken line L0 and the horizontal axis at the accelerator opening 100% is the maximum total driving torque.

  In addition, the distance between the solid line (thick line) L4 and the horizontal axis at a predetermined accelerator opening represents the driving torque of the in-wheel motor 8 on the right side of the rear wheel when the in-wheel motor 6 fails. The distance between the solid line (thin line) L1 and the solid line L4 at the accelerator opening represents the driving torque of the in-wheel motor 5 on the left side of the front wheel when the in-wheel motor 6 fails. Further, the distance between the solid line (thick line) L3 at the predetermined accelerator opening and the solid line L1 represents the driving torque of the in-wheel motor 7 on the left side of the rear wheel when the in-wheel motor 6 fails. Yes.

  Therefore, the distance between the solid line L3 and the horizontal axis when the accelerator opening is 100% is the total driving torque of each of the remaining three in-wheel motors 5, 7, 8 when the in-wheel motor 6 fails. Represents. That is, from the comparison between the broken line L0 and the solid line L3, when a failure occurs in the in-wheel motor 6, the total driving torque of the normal in-wheel motors 5, 7, and 8 is limited. I understand.

  The sum of the distance between the solid line L3 and the solid line L1 representing the driving torque of the in-wheel motor 7 and the distance between the solid line L1 and the solid line L4 representing the driving torque of the in-wheel motor 5, and the in-wheel motor. The distance between the solid line L4 representing the drive torque of 8 and the horizontal axis is set to be equal or nearly equal. That is, the sum of the drive torques output from the in-wheel motor 5 and the in-wheel motor 7 on the left side of the vehicle Ve and the drive torque output from the in-wheel motor 8 on the right side of the vehicle Ve are set to be equal or substantially equal. .

  Therefore, in the normal state, the in-wheel motor 8, that is, the failure side (the right side in this embodiment) is failed in contrast to the state where the torque distribution of the in-wheel motors 5, 6, 7, and 8 is equally distributed. The driving torque output from the in-wheel motor 8 of the non-wheel 4 is increased and the driving torque output from the in-wheel motor 5 is decreased, so that the total driving torque by the in-wheel motors 5, 7, 8 is reduced. As compared with the normal time is limited.

  Thus, according to the fail safe control during power running shown in the first control example, when a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 among the four, the three remaining normal in By controlling the drive torque of the wheel motors 5, 7, and 8 based on the control map shown in FIG. 2 as described above, the failure is not compared with the normal state in which no failure occurs in any in-wheel motor. The total driving torque by the in-wheel motors 5, 7, and 8 that are not generated is limited. Therefore, it is possible to prevent overload on each of the in-wheel motors 5, 7, and 8 and to stably secure the driving force of the vehicle Ve by the normal in-wheel motors 5, 7, and 8.

  Further, when the total driving torque is limited, the output of the in-wheel motor 6 that causes the driving torque to act on the wheel 2 in which the failure has occurred is limited, and the wheel 2 and the vehicle Ve in which the failure has occurred (or in the left-right direction) (or The output of the in-wheel motor 8 that causes the drive torque to act on the wheel 4 in which no failure on the same side occurs in the width direction) is increased. Therefore, the total driving torque can be limited without disturbing the balance of driving force in the left-right direction of the vehicle Ve.

  When the required driving force is large and exceeds the thermal rated torque T2, the wheel on the opposite side in the left-right direction of the vehicle Ve and the in-wheel motor 6 that causes the driving torque to act on the wheel 2 that has failed (this embodiment) Then, the output of the in-wheel motor (in-wheel motors 5 and 7 in this embodiment) that applies driving torque to the wheels 1 and 3) is increased, and at the same time, the steering angle by the steering device 16 is automatically controlled to control the vehicle Ve. You can also correct the direction of travel. As a result, even if the driving force becomes uneven in the left-right direction of the vehicle Ve in order to prevent the in-wheel motors 5, 7, 8 from exceeding the thermal rated torque T2, the steering device 16 By automatically executing the automatic steering, it is possible to prevent the vehicle Ve from being deflected.

  Further, when the required driving force is larger, by outputting the driving torque of each in-wheel motor 5, 7, 8 by temporarily exceeding the thermal rated torque T2 within a range that does not exceed the allowable maximum torque T1, It is possible to respond as much as possible to the driver's request.

(Second control example)
FIG. 3 shows a control map applied in fail-safe control during power running as a second control example of the present invention. The control map in FIG. 3 is substantially the same as the control map shown in FIG. 2 described above, and this second control example is any one in-wheel motor (in this embodiment, the in-wheel on the right side of the front wheel). When the motor 6) fails, the vehicle Ve is driven at the front or rear wheel drive (in this embodiment, the rear wheel drive by the in-wheel motors 7 and 8) to stabilize the travel of the vehicle Ve. Control.

  In the second control example, when the required driving force, that is, the accelerator opening, is relatively small as shown by the range A in the control map of FIG. 3, the vehicle Ve on the side where no failure occurs in the left-right direction, Control is performed such that the driving torque of the wheel facing the wheel where the failure occurs in the front-rear direction of the vehicle Ve is larger than the driving torque of the wheel facing the wheel where the failure occurs in the left-right direction. That is, in this embodiment, when a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 and the accelerator opening is relatively small, the driving torque of the in-wheel motor 5 interlocked with the left front wheel 1 is increased. The drive torque of the in-wheel motor 7 that is decreased and interlocked with the rear wheel 3 on the left side is increased, and the drive torque distribution before and after the vehicle Ve is set to the state of “front wheel <rear wheel”. Therefore, the driving mode of the vehicle Ve is controlled in a rear wheel driving state by the outputs of the in-wheel motors 7 and 8 of the left and right rear wheels 3 and 4 or a driving state mainly having the rear wheels 3 and 4.

  On the other hand, for example, when an in-wheel motor 7 linked to the left rear wheel 3 fails and the accelerator opening is relatively small, the in-wheel motor 8 linked to the right rear wheel 4. The driving torque of the in-wheel motor 6 interlocked with the right front wheel 2 is controlled to be larger than that of the driving torque. That is, the driving torque of the in-wheel motor 8 interlocked with the right rear wheel 4 is reduced, and the driving torque of the in-wheel motor 5 interlocked with the left front wheel 1 is increased, so that the driving torque before and after the vehicle Ve is increased. The distribution is set to “front wheel> rear wheel”. Therefore, the driving mode of the vehicle Ve is controlled in a front wheel driving state by the outputs of the in-wheel motors 5 and 6 of the left and right front wheels 1 and 2 or a driving state mainly having the front wheels 1 and 2.

  Furthermore, in the second control example, as indicated by a range A in the control map of FIG. 3, when the required driving force, that is, the accelerator opening is relatively small, the side where the vehicle Ve does not fail in the left-right direction is generated. Of the front and rear wheels, the front wheels are controlled to output the drive torque earlier than the rear wheels. That is, in this embodiment, a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2, and when the accelerator opening is relatively small, the in-wheel motor interlocked with the left front wheel 1 where no failure occurs. 5 is output prior to the in-wheel motor 7 interlocking with the left rear wheel 3. Therefore, for example, the friction coefficient of the traveling road surface can be detected by the front wheels 1 and 2 prior to the torque control of the rear wheels 3 and 4 during traveling.

  Thus, according to the fail safe control at the time of power running shown in the second control example, even if a failure occurs in any one of the wheels, the vehicle Ve is stabilized in the form of rear wheel drive or front wheel drive. Can be run.

  Further, when a failure occurs in one of the left and right front wheels 1 (or 2), the driving torque of the other front wheel 2 (or 1) is the other, that is, the rear wheel 4 (or 3) on the side where no failure occurs. ) Is output before. Therefore, it is possible to detect information on the friction coefficient of the road surface on the front wheel 1 (or 2) of the vehicle Ve and appropriately control the driving torque of the rear wheel 3 (or 4) based on the information.

(Third control example)
FIG. 4 shows a control map applied in fail-safe control during power running as a third control example of the present invention. This third control example takes into account the cooling effect during running when a failure occurs in either the left or right in-wheel motor on the front wheels 1 and 2 side (in this embodiment, the in-wheel motor 6 on the right side of the front wheel). The driving torque of the other in-wheel motor on the other front wheels 1 and 2 side where the failure has not occurred (in this embodiment, the in-wheel motor 5 on the left side of the front wheel) is made larger than that on the rear wheels 3 and 4 side. This is control for extending the travelable distance or the travelable time.

  In this third control example, there is a request when a failure occurs in either the left or right in-wheel motor 5 (or 6) on the front wheels 1 and 2 side, as indicated by a range B in the control map of FIG. When the driving force, that is, the accelerator opening is relatively large, the driving torque of the front wheel on the side where no failure occurs in the left-right direction of the vehicle Ve is greater than the driving torque of the rear wheel on the side where no failure occurs in the left-right direction. Is also controlled to be larger. That is, in this embodiment, when a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 and the accelerator opening is relatively large, the driving torque of the in-wheel motor 5 interlocked with the left front wheel 1 is increased. The driving torque of the in-wheel motor 7 interlocked with the left rear wheel 3 is increased. In contrast to this, when a failure occurs in the in-wheel motor 5 linked to the left front wheel 1 and the accelerator opening is relatively large, the driving torque of the in-wheel motor 6 linked to the right front wheel 2 is increased. However, the driving torque of the in-wheel motor 8 interlocked with the right rear wheel 4 is increased.

  When the vehicle Ve travels, when the in-wheel motors 5, 6, 7, and 8 are air-cooled, the in-wheel motors on the front wheels 1 and 2 side rather than the in-wheel motors 7 and 8 on the rear wheels 3 and 4 side. 5 and 6 have a better cooling effect. Therefore, the in-wheel motors 5 and 6 on the front wheels 1 and 2 side can set higher thermal rated torque than the in-wheel motors 7 and 8 on the rear wheels 3 and 4 side. Therefore, the torque distribution of the in-wheel motors 5 and 6 on the front wheels 1 and 2 side is distributed to the in-wheels on the rear wheels 3 and 4 side rather than the case where the driving torques of the front and rear in-wheel motors 5, 6, 7 and 8 are equally distributed. By making it larger than the wheel motors 7 and 8, the travelable distance or travelable time after the occurrence of a failure can be extended.

  Thus, according to the fail-safe control during power running shown in the third control example, a failure occurs in either the left or right in-wheel motor 5 (or 6) on the front wheels 1 and 2 side, and the required driving force is relatively If it is large, the driving torque of the other in-wheel motor 6 (or 5) on the other side of the front wheels 1 and 2, that is, the side where the failure has not occurred is the other in-wheel motor 8 (or the rear wheel 3 or 4 side). It is made larger than 7). For this reason, it is possible to increase the torque distribution of the in-wheel motor 5 (or 6) on the front wheels 1 and 2 side, which has a good cooling efficiency during traveling and can set a large thermal rated torque, thereby extending the travelable time.

(Fourth control example)
Next, a specific example of fail-safe control during regeneration will be described as a fourth control example in the present invention. This fourth control example is a basic example of fail-safe control during regeneration, and is executed based on the control map of each in-wheel motor 5, 6, 7, 8 shown in FIG. The control map of FIG. 5 shows that when any one in-wheel motor (in this embodiment, the in-wheel motor 6 on the right side of the front wheel) fails, the remaining three in-wheel motors (that is, each in this embodiment) This is for controlling the braking torque of the in-wheel motors 5, 7, 8).

  Specifically, the control map of FIG. 5 includes a total braking torque that is a sum of braking torques acting on the wheels 1, 2, 3, and 4 with respect to a predetermined required braking force or regeneration command amount, and each wheel. The torque distribution or torque sharing ratio of 1, 2, 3, 4 is shown.

  In the control map of FIG. 5, the distance between the solid line (thick line) G2 at the predetermined regeneration command amount, that is, the required braking force, and the horizontal axis representing the regeneration command amount is the total braking torque of the entire vehicle Ve, that is, each in-wheel motor. 5, 6, 7, and 8 represent the sum of the maximum braking torques that can be output within the allowable maximum torque range.

  In addition, the distance between the solid line (thin line) G1 and the horizontal axis at a predetermined regeneration command amount represents the braking torque of the in-wheel motor 5 on the left side of the front wheel when a failure occurs in the in-wheel motor 6, and the predetermined regeneration The distance between the solid line (thin line) G3 and the solid line G1 in the command amount represents the braking torque of the in-wheel motor 7 on the left side of the rear wheel when a failure occurs in the in-wheel motor 6, and a predetermined regeneration command amount. The distance between the solid line (thin line) G4 and the solid line G3 indicates the braking torque of the in-wheel motor 8 on the right side of the rear wheel when the in-wheel motor 6 fails.

  The distance between the solid line G2 and the solid line G4 indicates that the braking torque acting on the right front wheel 2 interlocked with the in-wheel motor 6 when a failure occurs in the in-wheel motor 6, specifically, Represents the braking torque applied to the front wheel 2 by the brake device 12 provided on the front wheel 2. Therefore, the distance between the solid line G2 and the horizontal axis representing the regenerative command amount is the braking torque of the entire vehicle Ve when the in-wheel motor 6 fails, that is, the wheels 1, 2, 3, 4 Represents the total braking torque acting on.

  On the other hand, FIG. 8 shows the in-wheel motors 5, 6 in a normal state in which no failure occurs in any of the wheels 1, 2, 3, 4 and the in-wheel motors 5, 6, 7, 8 linked thereto. 7, 8 and 8 and a control map for explaining fail-safe control according to the prior art when a failure occurs in the in-wheel motor 6 on the right side of the front wheel.

  In the control map of FIG. 8, the distance between the solid line (thick line) G12 at a predetermined regeneration command amount and the horizontal axis representing the regeneration command amount, that is, the required braking force, is the total braking torque of the vehicle Ve as a whole, that is, each The sum of the maximum braking torques that the in-wheel motors 5, 6, 7, and 8 can output within the allowable maximum torque range is shown. Further, the distance between the solid line (thin line) G13 at the predetermined regeneration command amount and the horizontal axis represents the braking torque of the in-wheel motor 7 on the left side of the rear wheel at the normal time, and the solid line (thin line) at the predetermined regeneration command amount. The distance between G14 and the above-mentioned solid line G13 represents the braking torque of the in-wheel motor 8 on the right side of the rear wheel at the normal time, and between the solid line (thin line) G11 and the above-mentioned solid line G14 at a predetermined regeneration command amount. The distance represents the braking torque of the in-wheel motor 5 on the left side of the front wheel at the normal time, and the distance between the solid line (thin line) G12 and the solid line G11 at a predetermined regeneration command amount is the right side of the front wheel at the normal time. The braking torque of the in-wheel motor 6 is represented.

  When a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 from the normal state shown in the control map of FIG. A braking torque acting on the right front wheel 2 is applied by the brake device 12 provided on the front wheel 2. That is, in the control map of FIG. 8 as described above, it is shown that a braking torque having a magnitude corresponding to the distance between the solid line G12 and the solid line G11 is applied to the wheel 2 by the brake device 12.

  Therefore, in the fail-safe control during regeneration according to the present invention, when each in-wheel motor 5, 6, 7, 8 is regeneratively controlled when a failure occurs, the total braking torque of the entire vehicle Ve is It can be seen that the normal state where no failure occurs is maintained.

  In the fourth control example, when a failure occurs in the in-wheel motor 6 interlocked with the front wheel 2 on the right side, the output of the in-wheel motor 6 in which the failure has occurred is limited, and the side on which the failure has occurred is limited. The braking torque output by the in-wheel motor 8 interlocked with the wheel where no failure occurs, that is, the right rear wheel 4 is increased. Then, the braking torque by the brake device 12 is applied to the wheel where the failure has occurred, that is, the right front wheel 2.

  That is, in the control map of FIG. 5, when a failure occurs in the in-wheel motor 6, between the solid line G4 and the solid line G3 corresponding to the magnitude of the braking torque of the in-wheel motor 8 interlocked with the right rear wheel 4. The distance is set to be larger than the distance between the solid line G14 and the solid line G13 corresponding to the magnitude of the braking torque of the in-wheel motor 8 on the right rear wheel in the normal state in the control map of FIG. Yes. Then, the increased braking torque of the in-wheel motor 8 and the braking torque of the in-wheel motor 6 that is limited or reduced due to the occurrence of a failure are added or subtracted, so that the amount that is insufficient with respect to the total braking torque at the normal time is insufficient. Is set to be applied to the wheel 2 by the brake device 12. Therefore, even when a failure occurs in the in-wheel motor 6, the total braking torque of the entire vehicle Ve is maintained at the same magnitude as the total braking torque at the normal time.

  Thus, according to the fail-safe control during regeneration shown in the fourth control example, when a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 out of the four, the remaining three By controlling the driving torques of the wheel motors 5, 7, and 8 based on the control map shown in FIG. 5 as described above, the total driving torque of the entire vehicle Ve has failed in any in-wheel motor. Not maintained in the same state as normal. Then, the output of the in-wheel motor 6 that applies a braking torque to the wheel 2 in which the failure has occurred is limited, and the wheel 2 in which the failure has occurred and the wheel on which the failure on the right side, that is, the right side, has not occurred on the vehicle Ve. 4, the output of the in-wheel motor 8 that applies the braking torque is increased, and the braking torque is applied to the wheel 2 in which the brake device 12 has failed. Therefore, the total braking torque can be maintained without disturbing the balance of the braking force in the left-right direction of the vehicle Ve. Further, even if a failure occurs in the in-wheel motor 6 and the amount of power generated during regeneration by the in-wheel motor 6 is reduced, the in-wheel motor 8 that applies a braking torque to the wheel 4 in which no failure has occurred. By increasing the output, the amount of power generated by the normal in-wheel motor 8 can be increased, and the generated power during regeneration can be ensured.

(Fifth control example)
FIG. 6 shows a control map applied in fail-safe control during regeneration as a fifth control example of the present invention. The control map of FIG. 6 is basically the same as the control map shown in FIG. 5 described above, and this fifth control example is the in-wheel motor on either the left or right side of the front wheels 1 and 2 (this In the embodiment, when a failure occurs in the in-wheel motor 6 on the right side of the front wheel, in-wheel motors on the other front wheels 1 and 2 side where no failure occurs in consideration of the cooling effect during traveling (in this embodiment, the front wheel In this control, the braking torque of the left in-wheel motor 5) is made larger than that of the rear wheels 3 and 4 to extend the travelable distance or travelable time after the occurrence of a failure.

  In the fifth control example, there is a request when a failure occurs in either the left or right in-wheel motor 5 (or 6) on the front wheels 1 and 2 side, as indicated by a range C in the control map of FIG. When the braking force, that is, the regenerative command amount is relatively large, the braking torque of the front wheel on the side where no failure occurs in the left-right direction of the vehicle Ve is greater than the braking torque of the rear wheel on the side where no failure occurs in the left-right direction. Is also controlled to be larger. That is, in this embodiment, when a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 and the regenerative command amount is relatively large, the braking torque of the in-wheel motor 5 interlocked with the left front wheel 1 is increased. The braking torque of the in-wheel motor 7 interlocked with the left rear wheel 3 is increased. In contrast to this, when a failure occurs in the in-wheel motor 5 interlocked with the left front wheel 1 and the regenerative command amount is relatively large, the braking torque of the in-wheel motor 6 interlocked with the right front wheel 2 However, the braking torque of the in-wheel motor 8 interlocked with the right rear wheel 4 is increased.

  As in the case of the fail-safe control during power running shown in the third control example described above, when the in-wheel motors 5, 6, 7, and 8 are air-cooled when the vehicle Ve travels, the rear wheels This is based on the fact that the in-wheel motors 5 and 6 on the front wheels 1 and 2 have a better cooling effect than the in-wheel motors 7 and 8 on the 3 and 4 sides. Therefore, the torque distribution of the in-wheel motors 5 and 6 on the front wheels 1 and 2 side is distributed to the in-wheels on the rear wheels 3 and 4 side rather than the case where the braking torques of the front and rear in-wheel motors 5, 6, 7 and 8 are equally distributed. By making it larger than the wheel motors 7 and 8, the travelable distance or travelable time after the occurrence of a failure can be extended.

  Thus, according to the fail-safe control during regeneration shown in the fifth control example, a failure occurs in either the left or right in-wheel motor 5 (or 6) on the front wheels 1 and 2 side, and the required braking force is relative. If it is large, the braking torque of the other in-wheel motor 6 (or 5) on the other side of the front wheels 1 and 2, that is, the side where the failure has not occurred is the other in-wheel motor 8 (or the rear wheel 3 or 4 side). It is made larger than 7). For this reason, it is possible to increase the torque distribution of the in-wheel motor 5 (or 6) on the front wheels 1 and 2 side, which has a good cooling efficiency during traveling and can set a large thermal rated torque, thereby extending the travelable time.

(Sixth control example)
FIG. 7 shows a control map applied in fail-safe control during regeneration as a sixth control example of the present invention. The sixth control example is a case where a failure has occurred in any one of the in-wheel motors (in this embodiment, the in-wheel motor 6 on the right side of the front wheel), and the required braking force, that is, the regenerative command amount is relatively small. In addition, the braking torque generated by the brake device for the failed wheel is applied at an early stage to effectively utilize the power generated during regeneration by the normal in-wheel motor (in-wheel motor 8 on the right side of the rear wheel in this embodiment). It is control for.

  In the sixth control example, when the regenerative command amount is relatively small as indicated by the range D in the control map of FIG. 7, no failure occurs on the side where the failure in the left-right direction of the vehicle Ve has occurred. The braking torque of the wheel is limited, and control is performed so that the time when the wheel where the failure occurs is braked by the brake device is relatively advanced. That is, in this embodiment, when a failure occurs in the in-wheel motor 6 interlocked with the right front wheel 2 and the regenerative command amount is relatively small, the braking torque of the in-wheel motor 8 interlocked with the right rear wheel 4 Is reduced, and braking by the brake device 12 on the right front wheel 2 in which a failure has occurred is executed early.

  Thus, according to the fail-safe control during regeneration shown in this sixth control example, a failure occurs on either the left or right wheel, and when the required braking force is relatively small, The braking torque of the normal wheel is limited, and braking by the brake device for the failed wheel is performed at an early stage. Therefore, the regenerative power generation by the in-wheel motor of the normal wheel on the side where the failure has occurred can be executed as effectively as possible.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means for executing steps S3 and S5 described above corresponds to the “fail-safe means” in the present invention. Among them, the functional means for executing step S3 corresponds to the means for executing “fail safe control during power running” in the present invention, and the functional means for executing step S5 is “fail safe during regeneration” in the present invention. It corresponds to a means for executing “control”.

  DESCRIPTION OF SYMBOLS 1, 2 ... Front wheel 3, 4 ... Rear wheel 5, 6, 7, 8 ... In-wheel motor (electric motor) 11, 12, 13, 14 ... Brake device, 16 ... Steering device, 17 ... Electronic control device ( ECU), Bo ... body, Ve ... vehicle.

Claims (6)

A control device for a four-wheel independent drive vehicle that includes an electric motor having a power running function and a regenerative function as a driving force source, and a brake device that brakes the wheels by frictional force, and can independently control the torque of the four wheels on the front, rear, left and right In
When the electric motor is subjected to power running control when a failure occurs in any one of the four wheels, the total driving torque of the entire vehicle is limited, and when the electric motor is regeneratively controlled, the entire vehicle a total braking torque means that maintain the normal state of the fail does not occur in the case of limiting the total drive torque, while limiting the driving torque which the electric motor wheels the fail has occurred and outputs When the drive torque output by the motor of the wheel on the side where the failure in the left-right direction has not occurred is increased and the motor is regeneratively controlled, the motor of the wheel on which the failure has occurred outputs While limiting the braking torque, increasing the braking torque output by the motor of the wheel on the side where the failure has occurred and increasing the failure. Control device for four-wheel independent drive vehicle, characterized in that Le is provided with a full Eirusefu means for applying a braking torque by the brake device for the wheel caused. The fail-safe means, if the previous SL motor is powering the control and the required driving force is relatively small, on the side where failure in the lateral direction does not occur, to face in the longitudinal direction to the wheel in which the fail has occurred control device for four-wheel independent drive vehicle according to claim 1, the driving torque of the wheel, characterized in that it comprises means you greater than the driving torque of the wheel that faces in the lateral direction to the wheel in which the failure has occurred. The fail-safe means drives the front wheel on the side where no failure occurs when the electric motor is controlled in power running and the required driving force is relatively large when a failure occurs on either the left or right front wheel. When the torque is made larger than the driving torque of the rear wheel where the failure does not occur, and the motor is regeneratively controlled and the required braking force is relatively large, the braking torque of the front wheel where the failure does not occur 2. The control device for a four-wheel independent drive vehicle according to claim 1, further comprising means for increasing the braking torque of the rear wheel on the side where the failure does not occur. The fail-safe means is configured such that when the electric motor is subjected to power running control when a failure occurs in any one of the left and right front wheels, the drive torque of the front wheel on the side where the failure does not occur does not occur. control device for four-wheel independent drive vehicle according to claim 1, characterized in that it comprises means you output before the rear wheel side. The fail-safe means, before Symbol motor is regenerative control and the required braking force when relatively small, the fail is that the fail while limiting the braking torque of the wheel that does not occur side fail resulting generated 2. The control device for a four-wheel independent drive vehicle according to claim 1, further comprising means for relatively speeding up the time when the wheel is braked by the brake device. Before Symbol motor is provided to the wheel in or near the four wheels each, of claims 1 to 5, characterized in that it comprises an in-wheel motor for applying a torque transmits power directly to the four wheels respectively The control apparatus of the four-wheel independent drive vehicle in any one .

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