WO2016031663A1

WO2016031663A1 - Drive control device for wheel independent driving vehicle

Info

Publication number: WO2016031663A1
Application number: PCT/JP2015/073331
Authority: WO
Inventors: 剛志神田
Original assignee: Ntn株式会社; 剛志神田
Priority date: 2014-08-27
Filing date: 2015-08-20
Publication date: 2016-03-03
Also published as: JP6411132B2; JP2016048987A

Abstract

Provided is a drive control device for a wheel independent driving vehicle, which makes it possible to avoid an unstable behavior when restricting the output of motor torque during high-speed driving and to take an evacuation action even when the wheel on one side is failed. The present invention is applied to a drive control device (20) of a vehicle in which the right and left drive wheels (2) of at least one of front and rear wheels can be independently driven by separate motors (6). An abnormality detection means (34) is provided that detects that an abnormality, i.e. overheat or failure has occurred in any of the motors (6) and a detection system, a power supply system, and a wiring system for driving the motors (6). An abnormality coping torque distribution change means (35) is provided that performs torque output restriction on any of the motors (6), said torque output restriction being set on a per-speed-region basis according to which speed region a current speed is in when an abnormality is detected by the means (34).

Description

Drive control device for wheel independent drive type vehicle

Related applications

This application claims the priority of Japanese Patent Application No. 2014-173030 filed on Aug. 27, 2014, which is incorporated herein by reference in its entirety.

The present invention, for example, in a vehicle (wheel independent drive type vehicle) that independently drives each wheel equipped with an in-wheel motor or the like, overheats the motor, its detection system, power supply system, wiring system, etc. The present invention relates to a drive control device for a wheel-independent drive vehicle that enables safety of travel and at least retreat travel when an abnormality that is a failure occurs.

2. Description of the Related Art Conventionally, in a drive control device for a wheel independent drive type vehicle, it has been proposed to provide an abnormal time corresponding torque distribution means for adjusting torque distribution of left and right drive wheels when an abnormality is detected (for example, Patent Document 1). In the case where an abnormality is detected, it has been proposed to limit the output of the motor of the driving wheel in which the abnormality is detected, and increase the output of the motor of the other normal driving wheel to compensate for the output decrease (for example, Patent Documents 2 and 3).

Japanese Patent No. 4513612 Japanese Patent No. 5359664 JP 2005-119647 A

In a wheel independent drive type vehicle, when an abnormality such as overheating or failure occurs in a motor or power device when turning at high speed, output may be limited such as output reduction or output stop. When performing such output restriction, it is necessary to consider so that the vehicle behavior does not become unstable. In addition, even when an abnormality occurs, it is preferable that retreat travel such as travel to the road shoulder or travel to a maintenance shop is possible.

In the above conventional technology, it has been proposed to adjust the torque distribution at the time of abnormality detection to compensate for the output drop, but there is no response according to the speed, and when limiting the output of the motor where the abnormality occurred The vehicle behavior may become unstable.

The object of the present invention is to avoid the unstable behavior when the motor torque output is restricted during high-speed running, and to enable the retraction action even if one wheel is lost. It is providing the drive control apparatus of a vehicle.

Hereinafter, in order to facilitate understanding, the present invention will be described with reference to the reference numerals of the embodiments for convenience.

A drive control device 20 for a wheel independent drive vehicle according to the present invention is a drive control device 20 capable of independently driving at least one left and right drive wheels 2 of front and rear wheels by individual motors 6.
An abnormality that is overheated or failed has occurred in the abnormality determination target that is provided for each drive wheel 2 and that is one of a detection system, a power supply system, and a wiring system for driving the motor 6. An abnormality detecting means 34 for detecting this,
When an abnormality is detected by the abnormality detection means 34, a torque output limit determined for each speed region is set for each of the motors 6 according to which speed region the current vehicle speed is in. An abnormality handling torque distribution changing means 35 to perform,
Is provided.
The “torque output restriction” includes torque stop. In addition, the above “torque output limitation” is only required to limit the torque as a result, and may be limited by the output value instead of the torque value.

According to this configuration, when it is detected that an abnormality that is overheating or failure has occurred in any of the motor 6 and its detection system, power supply system, and wiring system, the abnormality handling torque distribution changing means 35 Depending on which speed region the vehicle speed is in, the output of torque of the motor 6 determined for each speed region is limited. In this way, the speed region is determined, the torque output restriction content is made different depending on which speed region the current vehicle speed is in, and the restriction content according to the abnormality content or the vehicle speed. This avoids unstable behavior when the torque output of the motor 6 is restricted during high-speed traveling, and even if one wheel fails, it can be moved away from the road shoulder or evacuated when traveling to a maintenance shop. Is possible.

In the present invention, the abnormality-corresponding torque distribution changing means 35 is configured so that the abnormality detecting means 34 for either the left or right drive wheel 2 when the vehicle speed is in a high speed range divided into low speed, medium speed, and high speed. When an abnormality is detected, a torque output limit is applied to the motor 6 of the drive wheel 2 in which the abnormality is detected, and a torque output limit of the same value as this limit value is applied to the motor 6 of the drive wheel 2 on the opposite side of the left and right. You may make it hang against.

During high-speed driving, if the torque drops only on the left and right wheels due to overheating or failure, the vehicle will become unstable. However, in this configuration, when traveling at a high speed, the torque output limit of the same value as the torque output limit value of the motor 6 on the abnormality occurrence side is applied to the motor 6 of the drive wheel 2 on the opposite side. Hung. That is, the same torque output restriction is applied to both the left and right wheels. Therefore, the left and right torque can be balanced, and the unstable behavior of the vehicle can be avoided more reliably even during high speed traveling.

In the present invention, the abnormality-corresponding torque distribution changing means 35 is configured so that the abnormality detecting means 34 of either the left or right drive wheel 2 when the vehicle speed is in a low speed range of low speed, medium speed, and high speed. When an abnormality is detected, torque output limitation may be applied only to the motor 6 of the drive wheel 2 in which the abnormality is detected, and output limitation may not be applied to the motor 6 of the normal drive wheel 2. During low-speed driving, even if the left and right torques are unbalanced, there is no risk of unstable behavior such as spin. In this case, the normal drive wheels 2 are normally controlled without being restricted, so that even when the abnormal motor 6 cannot be driven, it is possible to evacuate to the road shoulder and the repair shop.

In the present invention, the abnormality-corresponding torque distribution changing means 35 is configured so that the abnormality detecting means 34 of either the left or right drive wheel 2 when the vehicle speed is in the middle speed range among the low speed, medium speed, and high speed. When abnormality is detected, torque output restriction may be applied to the motor 6 of the drive wheel 2 in which abnormality is detected. For the motor 6 of the normal drive wheel 2, a torque output restriction is applied according to the vehicle speed so that the restriction becomes stronger as the vehicle speed increases, and the degree of the torque output restriction is set to the low speed and the medium speed. The output limit may be set to zero at the vehicle speed of the threshold value V1 for determining the difference, and the limit value may be set to the same value as the motor 6 of the drive wheel 2 detected abnormally at the vehicle speed of the threshold value V2 for determining the medium speed and the high speed.

During medium-speed traveling, the behavior when an abnormality occurs and the motor 6 on the side where the abnormality occurs is limited to the behavior between the above-described high-speed traveling and low-speed traveling, and as the vehicle speed increases, the high-speed traveling It becomes close to the behavior of the case, and the behavior in the case of low-speed traveling becomes closer as the vehicle speed becomes slower. For this reason, the degree of restriction of the motor 6 on the normal side is set to zero output restriction at the vehicle speed of the threshold value V1 for discriminating between the low speed and the medium speed, and abnormality is detected at the vehicle speed of the threshold value V2 for discriminating between the medium speed and the high speed. By setting the limit value to the same value as that of the motor 6 of the drive wheel 2, both the prevention of the unstable behavior of the vehicle and the maintenance of the traveling speed within a safe range can be performed with a good balance. In addition, if the torque output limit value changes abruptly while driving at medium speed, unintended acceleration and deceleration occur, so it is preferable to switch smoothly according to the vehicle speed as described above.

In the present invention, the abnormality-corresponding torque distribution changing means 35 is configured so that the abnormality detecting means 34 of both the left and right drive wheels 2 is abnormal when the vehicle speed is in a high speed range of low speed, medium speed and high speed. When detected, the torque output limit is applied to the motors 6 of both drive wheels 2, and this limit is performed according to the type and degree of abnormality, and the torque output limit value of the left and right motors 6 is the torque between the left and right torques. The limit value of both wheels may be matched with the lower limit value.

If an abnormality occurs in both the left and right wheels, even during high-speed driving, the torque output is limited according to the type and degree of abnormality as described above, so safety can be obtained without excessive limitation. Travel speed can be maintained. For example, in the case of a slight abnormality such as a slight overheating, there is a strong possibility that overheating is eliminated and the vehicle returns to normal by maintaining traveling with a certain amount of torque output limited. On the contrary, in the case of a severe abnormality such as disconnection, the motor 6 is stopped. Thus, both safety and runnability can be obtained by performing restriction according to the type and degree of abnormality. Further, when limiting according to the type and degree of abnormality as described above, the output limit value of the torque of the left and right motors 6 is matched with the limit value of both wheels to the lower one of the left and right limit values. By doing so, the right and left drive balance can be obtained, and unstable behavior can be avoided more reliably.

In the present invention, the abnormality-corresponding torque distribution changing unit 35 detects that the abnormality detecting unit 34 of both the left and right drive wheels 2 is abnormal when the vehicle speed is in a low speed range of low speed, medium speed, and high speed. Upon detection, torque output limitation may be performed for each motor 6 of the left and right drive wheels 2 in accordance with the type and degree of abnormality. During low-speed driving, even if the left and right torques are unbalanced, there is no risk of unstable behavior such as spin. In this case, by restricting the torque output according to the type and degree of abnormality for each motor 6 of each of the left and right drive wheels 2, the traveling speed of the retreat travel can be as much as possible without causing problems of unstable behavior. Can be secured.

In the present invention, the abnormality-corresponding torque distribution changing means 35 is configured so that the abnormality detecting means 34 for both the left and right drive wheels 2 is abnormal when the vehicle speed is in the medium speed range of low speed, medium speed, and high speed. Is detected, the motor 6 of both drive wheels 2 is limited in torque output, and this limitation is performed according to the type and degree of abnormality. However, at the vehicle speed of the threshold V2 for determining the medium speed and the high speed, The limit value indicated by the torque value is adjusted to the lower value of the left and right, and the vehicle speed of the threshold value V1 for discriminating between the low speed and the medium speed is completely independent for each motor 6 of the left and right drive wheels 2. In order to limit the output of torque according to the type and degree of abnormality, the degree of restriction related between the left and right motors 6 may be relaxed as the vehicle speed decreases.

During medium-speed traveling, the behavior when an abnormality occurs and the motor 6 on the side where the abnormality occurs is limited to the behavior between the above-described high-speed traveling and low-speed traveling, and as the vehicle speed increases, the high-speed traveling It becomes close to the behavior of the case, and the behavior in the case of low-speed traveling becomes closer as the vehicle speed becomes slower. Therefore, the restriction is performed according to the type and degree of abnormality. At the vehicle speed of the threshold value V2 for discriminating between the medium speed and the high speed, the limit value indicated by the torque value is adjusted to the lower value of the left and right, and the low speed The vehicle speed of the threshold value V1 for discriminating between the vehicle speed and the medium speed depends on the vehicle speed so as to limit the output of torque according to the type and degree of abnormality for each motor 6 of the left and right drive wheels 2 completely independently. Thus, by varying the degree of relation of the restriction of the left and right motors 6, it is possible to balance both the prevention of the unstable behavior of the vehicle and the maintenance of the traveling speed within a safe range.

In the present invention, the motor 6 includes an in-wheel including the motor 6, a wheel bearing 4 that supports the drive wheel 2, and a speed reducer 7 that decelerates the rotation of the motor 6 and transmits the rotation to the wheel bearing. The motor drive device IWM may be configured. In the case of a vehicle provided with such an in-wheel motor drive device IWM, each effect of this invention is acquired effectively.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the invention.

The present invention will be understood more clearly from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in a plurality of drawings indicate the same or corresponding parts.

It is a block diagram of the conceptual composition which shows the wheel independent drive type vehicle carrying the drive control device concerning a 1st embodiment of this invention with a top view. It is sectional drawing of the in-wheel motor drive device in the vehicle. It is a block diagram of a control system of the drive control device. It is a flowchart which shows the output restriction content by the abnormality corresponding torque distribution change means of the drive control device. It is a graph which shows the example of an output limitation by the abnormality corresponding torque distribution change means of the drive control device. It is a graph which shows the other output restriction example by the abnormality corresponding torque distribution change means of the drive control device. It is a block diagram of the conceptual structure which shows the wheel independent drive type vehicle carrying the drive control apparatus which concerns on other embodiment of this invention with a top view. It is a block diagram which simplifies and shows the control system of the drive control apparatus.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a conceptual configuration showing, in plan view, an electric vehicle that is a wheel independent drive type vehicle equipped with a drive control device according to this embodiment. This electric vehicle is a four-wheeled vehicle in which the wheels 2 that are the left and right rear wheels of the vehicle body 1 are drive wheels and the wheels 3 that are the left and right front wheels are driven wheels. The driven wheel 3 which is the front wheel is a steering wheel. The left and

right drive wheels

2, 2 as rear wheels are driven by independent traveling motors 6. Each motor 6 constitutes an in-wheel motor drive device IWM described later. Each drive wheel 2 and driven wheel 3 is provided with a friction brake (FIG. 2).

FIG. 2 is a longitudinal sectional view of an in-wheel motor drive device IWM in this electric vehicle. Each in-wheel motor drive unit IWM has a motor 6, a speed reducer 7, and a wheel bearing 4, and a part or all of these are arranged in the drive wheel 2. The rotation of the motor 6 is transmitted to the drive wheel 2 via the speed reducer 7 and the wheel bearing 4. A brake rotor 5 constituting the brake is fixed to a flange portion of the hub wheel 4 a of the wheel bearing 4, and the brake rotor 5 rotates integrally with the drive wheel 2. The motor 6 is, for example, an embedded magnet type synchronous motor in which a permanent magnet is built in a core portion of an internal rotor 6a. This motor 6 is a motor in which a radial gap is provided between a stator 6 b fixed to the housing 8 and a rotor 6 a attached to the rotation output shaft 9.

Explain the control system. As shown in FIG. 1, a drive control device 20 including an ECU 21 and a plurality (two in this example) of inverter devices 22 is mounted on the vehicle body 1. The ECU 21 is a higher-level control unit that performs overall control and cooperative control of the entire vehicle and gives commands to each inverter device 22. Each inverter device 22 controls the corresponding traveling motor 6 in accordance with a command from the ECU 21. The ECU 21 includes a computer such as a microcomputer, a ROM (Read Only Memory) having a program executed on the computer, and various electronic circuits such as a RAM (Random Access Memory) and a coprocessor (Co-Processor). The The ECU 21 and each inverter device 22 are connected by an in-vehicle communication network such as a CAN (control area network).

The ECU 21 has command torque calculation means 47 and torque distribution means 48. The command torque calculation means 47 mainly generates an acceleration / deceleration command for driving the entire vehicle as a torque value from the accelerator opening signal output from the accelerator operation unit 16 and the deceleration command output from the brake operation unit 17. To do. The torque distribution unit 48 uses the acceleration / deceleration command (torque value) calculated by the command torque calculation unit 47 using the steering angle signal output from the steering unit 15 to drive the left and

right drive wheels

2, 2. 6 and 6 and output to each inverter device 22.

Further, the command torque calculation means 47, when there is a deceleration command output from the brake operation unit 17, a regenerative braking torque command value for causing the motor 6 to function as a regenerative brake, and a friction applied to the friction brake (not shown). It has a function to distribute to the braking torque command value. The regenerative braking torque command value that functions as a regenerative brake is reflected in the torque command value of the acceleration / deceleration command that is given to the

motors

6 and 6 for traveling. The accelerator operation unit 16 and the brake operation unit 17 include pedals such as an accelerator pedal and a brake pedal, respectively, and an accelerator sensor 23 (FIG. 3) and a brace sensor (not shown) for detecting the operation amount of these pedals. The battery 19 is mounted on the vehicle body 1 and is used as a drive for the motor 6 and as a power source for the electrical system of the entire vehicle. Specifically, the torque distribution means 48 is a predetermined conversion function stored in an LUT (Look Up Table) realized by software or hardware, a software library, or equivalent hardware, etc. (Hereinafter, referred to as “embodiment model”), the torque values corresponding to the driving motors 6 of the respective drive wheels 2 are respectively calculated in response to the input of the acceleration / deceleration command and the steering angle signal. Hardware circuit or software function.

FIG. 3 is a block diagram of the control system of this drive control device. Hereinafter, description will be made with reference to FIG. 1 as appropriate. The inverter device 22 is provided for each motor 6 and includes a power circuit unit 28 and a motor control unit 29 that controls the power circuit unit 28. The motor control unit 29 is configured by an electronic circuit such as a microcomputer. The motor control unit 29 has information (eg, motor rotation speed, operating torque, motor temperature, inverter temperature described later, and drive) such as detection values and control values related to the in-wheel motor drive device IWM of the motor control unit 29. Power supply voltage, control power supply voltage, abnormality information, and the like).

The power circuit unit 28 includes an inverter 31 and a PWM driver 32 that drives the inverter 31. The inverter 31 converts the DC power of the battery 19 into three-phase AC power used for driving the motor 6. The inverter 31 includes a plurality of semiconductor switching elements (not shown), and the PWM driver 32 drives the semiconductor switching elements of the inverter 31 based on an on / off command described later. The semiconductor switching element includes, for example, an insulated gate bipolar transistor (IGBT).

The motor control unit 29 has a motor drive control unit 30 as a basic control unit. The motor drive control unit 30 converts it into a current command and performs pulse width modulation in accordance with an acceleration / deceleration command by a torque command or the like given from the ECU 21 which is the host control means, and gives an on / off command to the PWM driver 32 of the power circuit unit 28 . The motor drive control unit 30 obtains a motor current flowing from the inverter 31 to the motor 6 from the current sensor 38 and performs current feedback control. Further, the motor drive control unit 30 obtains the rotation angle of the rotor 6a (FIG. 2) of the motor 6 from the rotation angle detection means 33 and performs vector control. For the rotation angle detection means 33, a resolver or the like is used.

In this embodiment, the motor control unit 29 having the above-described configuration is provided with the following abnormality detection means 34 and the ECU 21 is provided with an abnormality corresponding torque distribution changing means 35. Further, temperature detecting means 36 for detecting the temperature of the motor 6 and temperature detecting means 37 for detecting the temperature of the inverter 31 are provided.

The abnormality detection means 34 is provided for each drive wheel 2 and includes the motor 6, a detection system (sensors) for driving the motor 6, a power supply system (inverter 31, etc.), a wiring system (in-vehicle communication network, It is detected that an abnormality that is an overheating or a failure has occurred in the abnormality determination target that is one of the sensors). As a specific example, the abnormality detection unit 34 constantly monitors the temperatures of the motor 6 and the inverter 31 with the

temperature detection units

36 and 37, and determines that the temperature is overheated when a set value set for each is exceeded. Further, disconnection or short-circuit of the rotation angle detection means 33 such as a resolver, the current sensor 38, and the in-vehicle communication network (CAN) is monitored to determine that it is in a failure state. Specifically, the abnormality detection unit 34 uses the above-described implementation model to output the output values of the

temperature detection units

36 and 37, the output values of the rotation angle detection unit 33 and the current sensor 38, and the CAN communication lines. It consists of a hardware circuit or a software function that receives an input of a signal value and calculates and outputs an abnormality detection signal value with reference to the set value or a predetermined threshold value (for example, for each monitoring location) When the abnormality is detected, a signal value “1” is output).

The abnormality-corresponding torque distribution changing means 35, when an abnormality is detected by the abnormality detecting means 34, according to which speed area the current vehicle speed is in, any one of the speed areas determined for each of the speed areas. The torque output of the motor 6 is limited. This torque output restriction includes the upper limit value of torque, the reduction of torque, and the stopping of torque. In this embodiment, the abnormality-corresponding torque distribution changing means 35 is provided in the torque distribution means 48 in the ECU 21 and changes, for example, an acceleration / deceleration command based on a torque value given from the torque distribution means 48 to each inverter device 22. Specifically, the abnormality corresponding torque distribution changing means 35 receives the input of each abnormality detection signal value and the vehicle speed using the above-described embodiment model, determines a speed region to which the vehicle speed belongs, and limits the torque upper limit value. It is composed of a hardware circuit or a software function that can output a command to reduce torque, a command to reduce torque, a command to make torque zero, or the like. Here, the above command or the like may be output without determining the speed region to which the vehicle speed belongs.

The current vehicle speed is obtained from the vehicle speed sensor 24 provided on the vehicle. In this embodiment, the speed region is a three-step region of low speed, medium speed, and high speed. The threshold values V1 and V2 between the regions may be arbitrarily set. For example, V1 and V2 are set to 30 km / h and 100 km / h, respectively, and the speed is low at 30 km / h or less, the medium speed at 30 to 100 km / h, and 100 km / h. Higher than h.

する Illustrates the conditions when output is stopped by the abnormality handling torque distribution changing means 35 and the case of limiting without stopping. For example, when there is a failure such as disconnection or short circuit of the rotation angle detection means 33 or the current sensor 38, the output is stopped. This is because the control itself cannot be performed. When the motor 6 or the inverter 31 is slightly overheated above the first threshold, for the purpose of protection, the motor 6 or the inverter 31 is limited so as to reduce the torque or limit the upper limit without stopping. In the case of severe overheating of a second threshold value higher than the first threshold value, the output is stopped. In the case of an abnormality in the in-vehicle communication network (disconnection, short circuit, etc.), no command is issued, so the output of the motors 6 for both the left and right drive wheels 2 is stopped.

Referring to FIG. 4, the torque output restriction contents according to the vehicle speed and the contents of the abnormality by the abnormality corresponding torque distribution changing means 35 will be described. The abnormality handling torque distribution changing means 35 constantly monitors whether or not an abnormality due to overheating or failure is detected by the abnormality detecting means 34 (step S1). At this time, it is also detected whether there is an abnormality in only one of the left and right wheels, or whether there is an abnormality in both wheels, and the above-described abnormality detection signals are monitored.

(Step S2)
If an abnormality on only one wheel is detected, the process proceeds to step S2, and it is determined whether the current vehicle speed is in a high speed range (V2 or higher), medium speed (V2 to V1), or low speed (V1 or lower). To do. In the case of high speed, the restriction is performed in step S4, in the case of medium speed, in step S5, and in the case of low speed, the restriction is performed in step S6. Examples of these restrictions will be described.

(Step S4)
In the case of the high speed region, when an abnormality on only one side is detected, an output restriction is applied to the torque of the motor 6 of the drive wheel 2 in which the abnormality is detected, and an output restriction of the torque having the same value as this restriction value is set. Is applied to the motor 6 of the drive wheel 2 on the opposite side. During high speed running, if the torque drops only on the left and right wheels due to overheating or failure, the running of the vehicle becomes unstable. However, as described above, when the vehicle is traveling at high speed, the torque output limit of the same value as the torque output limit value of the motor 6 on the abnormality occurrence side is applied to the motor 6 of the opposite drive wheel 2. Hung. That is, the same torque output restriction is applied to both the left and right wheels. As a result, a balance between the left and right torques can be obtained, and the unstable behavior of the vehicle can be more reliably avoided even during high-speed traveling.

(Step 6)
If an abnormality is detected in one of the left and right drive wheels 2 when the vehicle speed is in a low speed region, only the motor 6 of the drive wheel 2 in which the abnormality is detected is limited in torque output, and the normal drive wheel 2 The motor 6 is not limited in output. During low-speed driving, even if the left and right torques are unbalanced, there is no risk of unstable behavior such as spin. In this case, the normal driving wheels 2 are normally controlled without being restricted, and even when the abnormal motor 6 is in an inoperable state, it is possible to retreat to the road shoulder or to a repair shop.

(Step 5)
If an abnormality in one of the left and right drive wheels 2 is detected when the vehicle speed is in the medium speed range, torque output is limited for the motor 6 of the drive wheel 2 in which the abnormality has been detected. For the motor 6 of the normal drive wheel 2, a torque output restriction is applied according to the vehicle speed so that the restriction becomes stronger as the vehicle speed increases, and the degree of the torque output restriction is set to the low speed and the medium speed. The output limit is set to zero at the vehicle speed of the threshold value V1 for discriminating between and the limit value of the same value as the motor 6 of the drive wheel 2 in which the abnormality is detected at the vehicle speed of the threshold value V2 for discriminating between the medium speed and the high speed.

(Step S3)
If an abnormality is detected on both wheels, the process proceeds to step S3, and it is determined whether the current vehicle speed is in a high speed range (V2 or higher), medium speed (V2 to V1), or low speed (V1 or lower). In the case of high speed, the restriction is performed in step S7, in the case of medium speed, in step S8, and in the case of low speed, the restriction is performed in step S9. Examples of these restrictions will be described.

(Step S7)
If an abnormality in both the left and right drive wheels 2 is detected when the vehicle speed is in the high speed region, the torque output limit of the motor 6 of both drive wheels 2 is applied, and this restriction is set to the type and degree of abnormality. Accordingly, the output limit values of the torques of the left and right motors 6 are set so that the limit values of both wheels are matched with the lower limit value indicated by the torque value of the left and right.

When an abnormality occurs in both the left and right wheels, the traveling speed can be maintained while obtaining safety without restricting excessively by performing torque output restriction according to the type and degree of abnormality as described above. For example, in the case of a slight abnormality such as a slight overheating, there is a strong possibility that overheating is eliminated and the vehicle returns to normal by maintaining traveling with a certain amount of torque output limited. On the contrary, in the case of a high degree of abnormality such as disconnection, the motor 6 is stopped. Thus, both safety and runnability can be obtained by performing restriction according to the type and degree of abnormality. Further, when limiting according to the type and degree of abnormality as described above, the output limit value of the torque of the left and right motors 6 is matched with the limit value of both wheels to the lower one of the left and right limit values. By doing so, the right and left drive balance can be obtained, and unstable behavior can be avoided more reliably.

(Step S9)
If the abnormality detection means 34 for both the left and right drive wheels 2 detects an abnormality when the vehicle speed is in the low speed range, the type and degree of abnormality are independently determined for each motor 6 of each left and right drive wheel 2. The torque output is limited accordingly. During low-speed driving, even if the left and right torques are unbalanced, there is no risk of unstable behavior such as spin. In this case, by restricting the torque output according to the type and degree of abnormality for each motor 6 of each of the left and right drive wheels 2, the traveling speed of the retreat travel can be as much as possible without causing problems of unstable behavior. Can be secured.

(Step S8)
If an abnormality in both the left and right drive wheels 2 is detected when the vehicle speed is in the middle speed range, the torque output limit of the motor 6 of both drive wheels 2 is applied, and this restriction is set to the type and degree of abnormality. The threshold value V2 for discriminating between the medium speed and the high speed is adjusted according to the limit value indicated by the torque value to the lower one of the left and right values, and the threshold value V1 for discriminating between the low speed and the medium speed is determined. At the vehicle speed, the left and right motors 6 between the left and right motors 6 as the vehicle speed decreases so that the output of torque is limited in accordance with the type and degree of abnormality for each motor 6 of the left and right drive wheels 2 completely independently. Reduce the degree of association of restrictions.

During medium-speed traveling, the behavior when an abnormality occurs and the motor 6 on the side where the abnormality occurs is limited to the behavior between the above-described high-speed traveling and low-speed traveling, and as the vehicle speed increases, the high-speed traveling It becomes close to the behavior of the case, and the behavior in the case of low-speed traveling becomes closer as the vehicle speed becomes slower. Therefore, the restriction is performed according to the type and degree of abnormality. At the vehicle speed of the threshold value V2 for discriminating between the medium speed and the high speed, the limit value indicated by the torque value is adjusted to the lower value of the left and right, and the low speed The vehicle speed of the threshold value V1 for discriminating between the vehicle speed and the medium speed depends on the vehicle speed so as to limit the output of torque according to the type and degree of abnormality for each motor 6 of the left and right drive wheels 2 completely independently. Thus, by varying the degree of relation of the restriction of the left and right motors 6, both the prevention of the unstable behavior of the vehicle and the maintenance of the traveling speed within a safe range can be performed in a well-balanced manner.

As a specific example, FIG. 5 shows a case where the motor 6 of the left driving wheel 2 has no output limitation and the output limitation value of the motor 6 of the right driving wheel 2 is 0 Nm (output stop) in the low speed region. In this case, as shown in FIG. 5A, the motor 6 of the left driving wheel 2 has no output limitation in the low speed region where the vehicle speed is up to V1, the output limit value is the maximum torque, and in the high speed region where the vehicle speed is V2 or higher. The output limit value is 0 Nm (output stop). In the medium speed range, the output limit value gradually approaches 0 from the maximum torque as the vehicle speed increases. Further, as shown in FIG. 5B, the right drive wheel 2 has an output limit value of 0 Nm (output stop) even at low speeds, so that the output limit value is 0 Nm (even in the medium speed region and high speed region). Output stop).

As another specific example, FIG. 6 shows a case where the output limit value of the motor 6 of the left drive wheel 2 is 300 Nm and the output limit value of the motor 6 of the right drive wheel 2 is 100 Nm in the low speed region. In this case, as shown in FIG. 6A, the motor 6 of the left driving wheel 2 has an output limit value of 300 Nm in the low speed range up to V1, and an output limit value of 100 Nm in the high speed range where the vehicle speed is V2 or higher. It is. In the medium speed region, the output limit value approaches from 100 Nm to 100 Nm as the vehicle speed increases. Further, as shown in FIG. 5B, the right drive wheel 2 has an output limit value of 100 Nm even at a low speed, and therefore the output limit value is set to 100 Nm even in the medium speed region and the high speed region.

As described above, according to the drive control device for the wheel independent drive type vehicle, it is detected that an abnormality that is overheated or failed has occurred in any of the motor 6 and its detection system, power supply system, and wiring system. Then, the abnormality-corresponding torque distribution changing unit 35 limits the output of the torque of the motor 6 determined for each speed region according to which speed region the current vehicle speed is in. In this way, the speed region is determined, the torque output restriction content is made different depending on which speed region the current vehicle speed is in, and the restriction content according to the abnormality content or the vehicle speed. This avoids unstable behavior when the torque output of the motor 6 is restricted during high-speed traveling, and even if one wheel fails, it can be moved away from the road shoulder or evacuated when traveling to a maintenance shop. Is possible.

In the first embodiment, the case where the inverter device 22 is physically present for each motor 6 has been described. However, as shown in FIGS. 7 and 8, the inverter device 22 is physically May drive the left and right motors 6 as a single unit. In this case, the power circuit unit 28 (see FIG. 3) is physically provided individually corresponding to each motor 6 in one inverter device 22, but the motor control unit 29 that performs control is mutually connected. An electronic circuit including a common microcomputer or the like is used to drive the left and right motors 6 in time division processing or parallel processing, and conceptually there are two inverter devices 22. Similarly, the abnormality detection means 34 provided in the inverter device 22 is conceptually provided for each of the left and right motors 6.

The vehicle speed calculation unit 39 in the example of FIG. 8 is a means for calculating the vehicle speed from a rotation detector (not shown) that detects the rotation speed of the driven wheel 3 (FIG. 1), and the calculated vehicle speed is the torque corresponding to the abnormality. The distribution changing means 35 is used for control. As for the vehicle speed, any of the vehicle speed sensor 24 and the vehicle speed calculation unit 39 of FIG. 3 may be used in any of the examples of FIGS.

Further, although the abnormality handling torque distribution changing means 35 is provided in the ECU 21, the abnormality handling torque distribution changing means 35 is provided in any of the ECU 21 and the inverter device 22 as shown in FIGS. 3 and 8. good. When provided in the inverter device 22, the command torque given from the torque distribution means 48 is corrected by the abnormality corresponding torque distribution changing means 35 in the inverter device 22.

In the above embodiment, the case where the present invention is applied to a rear-wheel drive vehicle has been described. However, a two-wheel independent drive vehicle that independently drives the left and right front wheels may be applied as the vehicle. Further, as the vehicle, a four-wheel independent drive vehicle that drives the left and right front wheels independently and drives the left and right rear wheels independently may be applied. The in-wheel motor drive device IWM is a so-called direct motor type in which a cycloid reducer, a planetary reducer, a two-axis parallel reducer, and other reducers can be applied. Also good.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily assume various changes and modifications within the obvious scope by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the appended claims.

2 ... Driving wheel 4 ... Wheel bearing 6 ... Motor 7 ... Reducer 20 ... Drive controller 21 ... ECU
28 ... Power circuit unit 29 ... Motor control unit 33 ... Rotation angle detection means 34 ... Abnormality detection means 35 ... Abnormal response torque

distribution changing means

36, 37 ... Temperature detection means 38 ... Current sensor 48 ... Torque distribution means IWM ... In-wheel motor Drive device

Claims

A drive control device for a wheel independent drive vehicle capable of independently driving at least one left and right drive wheels of front and rear wheels with individual motors,
It is provided for each drive wheel and detects that an abnormality that is overheated or failed has occurred in the abnormality determination target that is one of the motor and a detection system for driving the motor, a power supply system, or a wiring system. Anomaly detection means to
An abnormality in which, when an abnormality is detected by the abnormality detecting means, the torque output limit determined for each speed region is limited for each of the motors depending on which speed region the current vehicle speed is in. Corresponding torque distribution changing means,
A drive control device for a wheel independent drive type vehicle characterized by comprising:
2. The drive control device for a wheel independent drive vehicle according to claim 1, wherein the abnormality-corresponding torque distribution changing means is either left or right when the vehicle speed is a high speed range divided into low speed, medium speed, and high speed. When the abnormality detecting means for one drive wheel detects an abnormality, the torque output limit is applied to the motor of the drive wheel in which the abnormality is detected, and the torque output limit of the same value as this limit value is Drive control device for a wheel independent drive type vehicle to be applied to the motor of the drive wheel.
3. The drive control apparatus for a wheel independent drive type vehicle according to claim 1 or 2, wherein the abnormality-response torque distribution changing means is a low speed region in which the vehicle speed is divided into low speed, medium speed, and high speed. When the abnormality detection means for either the left or right drive wheel detects an abnormality, a torque output limit is applied only to the drive wheel motor in which the abnormality is detected, and a normal drive wheel motor is not subjected to an output limit. Independently driven vehicle drive control device.
4. The drive control device for a wheel independent drive type vehicle according to claim 1, wherein the abnormality-corresponding torque distribution changing means has a medium speed out of the low speed, the medium speed, and the high speed. When the abnormality detection means for either the left or right drive wheel detects an abnormality when in the speed region, the output of the torque is limited for the motor of the detected drive wheel, and for the motor of the normal drive wheel, A torque output limit is applied according to the vehicle speed so that the limit becomes stronger as the vehicle speed becomes faster, and the output limit of this torque is set to zero at the vehicle speed of the threshold value V1 for discriminating between the low speed and the medium speed, A drive control apparatus for a wheel independent drive type vehicle having a limit value that is the same value as the motor of the drive wheel in which an abnormality is detected at a vehicle speed of a threshold value V2 for discriminating between the medium speed and the high speed.
5. The drive control device for a wheel independent drive type vehicle according to claim 1, wherein the abnormality-corresponding torque distribution changing means has a vehicle speed divided into a low speed, a medium speed, and a high speed. When the abnormality detection means for both the left and right drive wheels detects an abnormality when in the speed region, the motor of both drive wheels is subjected to torque output limitation, and this limitation is performed according to the type and degree of abnormality, The left and right motor torque output limit values are wheel independent drive type vehicle drive control devices that match the limit values of both wheels with the lower limit value indicated by the left and right torque values.
6. The drive control device for a wheel independent drive type vehicle according to claim 1, wherein the abnormality-corresponding torque distribution changing means has a vehicle speed divided into a low speed, a medium speed, and a high speed. When the abnormality detection means for both the left and right drive wheels detects an abnormality when in the speed region, a wheel independent drive type that limits torque output according to the type and degree of abnormality for each motor of the left and right drive wheels Vehicle drive control device.
7. The wheel independent drive type vehicle drive control device according to claim 1, wherein the abnormality-corresponding torque distribution changing means is a medium speed among vehicle speeds classified into low speed, medium speed, and high speed. If the abnormality detection means for both the left and right drive wheels detects an abnormality in the speed region, the torque output restriction is applied to the motors of both drive wheels, and this restriction is performed according to the type and degree of abnormality. However, at the vehicle speed of the threshold value V1 for determining the medium speed and the high speed, the limit value indicated by the torque value is adjusted to the lower value of the left and right at the vehicle speed of the threshold value V1 for determining the low speed and the medium speed. For each motor on the left and right drive wheels, the degree of relevance between the left and right motors is reduced as the vehicle speed decreases, so that the output of torque according to the type and degree of abnormality is completely independent. Weakening wheel independent drive type vehicle Drive control device.
The wheel independent drive type vehicle drive control device according to any one of claims 1 to 7, wherein the motor includes the motor, a wheel bearing supporting the drive wheel, and rotation of the motor. A drive control device for a wheel independent drive type vehicle that constitutes an in-wheel motor drive device including a reduction gear that decelerates and transmits the reduced gear to the wheel bearing.