WO2016031696A1

WO2016031696A1 - Drive control device for independent wheel drive-type vehicle

Info

Publication number: WO2016031696A1
Application number: PCT/JP2015/073477
Authority: WO
Inventors: 剛志神田
Original assignee: Ntn株式会社; 剛志神田
Priority date: 2014-08-29
Filing date: 2015-08-21
Publication date: 2016-03-03
Also published as: JP2016052164A; JP6534509B2

Abstract

Disclosed is a drive control device (20) that controls the drive of a vehicle including two motors (6, 6) each separately driving a left drive wheel (2) and a right drive wheel (2), the drive control device comprising: an abnormality detection means (34) that determines whether or not either the left drive wheel or the right drive wheel is in an abnormal state; and a torque limiting means (36) that, if the abnormality detection means (34) determines that either one of the left and right drive wheels (2) is in said abnormal state, stops the output of said one drive wheel (2) determined to be in said abnormal state, and limits the output torque of the other drive wheel (2) to an output torque at a rate set with respect to the maximum torque.

Description

Drive control device for wheel independent drive type vehicle

Related applications

This application claims the priority of Japanese Patent Application No. 2014-175052 filed on Aug. 29, 2014, which is incorporated herein by reference in its entirety.

For example, in the wheel independent drive type vehicle equipped with an in-wheel motor or the like, the drive control of the wheel independent drive type vehicle that enables retreat traveling to the road shoulder or the like when the output of one drive wheel is stopped. Relates to the device.

There has been proposed a technique for controlling the driving force as follows when the automobile is turning (Patent Document 1).
When the driving source of the front wheel on the outer side in the turning direction becomes unable to drive, the driving force for the front wheel on the inner side in the turning direction is gradually reduced, and the supply of the driving force is stopped after a predetermined time has elapsed.
-When the drive source of the front wheel on the inner side in the turning direction becomes unable to drive, the supply of driving force to the front wheel on the outer side in the turning direction is immediately stopped.

JP-A-8-168112

The control of the prior art requires a steering angle sensor, which makes the control complicated and expensive. Further, when one drive source becomes incapable of being driven, the normal supply of the drive force to the other drive source is stopped, so that the retreat traveling to the road shoulder or the like cannot be performed.
In a wheel independent drive type vehicle equipped with an in-wheel motor etc., for example, when turning at a high speed, if one wheel stops output due to overheating or abnormality of the motor or power device etc., the vehicle behavior will not become unstable Such consideration is necessary. In addition, even if an abnormality occurs in a single-wheel motor or the like, it is desired to be able to perform retreat traveling such as movement to a road shoulder or movement to a repair shop or the like.

An object of the present invention is a vehicle drive control device including left and right motors that individually drive left and right drive wheels, and enables retreat travel to a road shoulder or the like when one of the drive wheels is in an abnormal state. It is providing the drive control apparatus of a vehicle.

The drive control device for a wheel independent drive vehicle according to the present invention is a drive control device that controls the drive of a vehicle including two

motors

6 and 6 that individually drive the left drive wheel 2 and the right drive wheel 2. There,
An abnormality detecting means 34 for detecting whether the left driving wheel 2 and the right driving wheel 2 are in an abnormal state;
When the abnormality detection unit 34 determines that one of the left driving wheel 2 and the right driving wheel 2 is in the abnormal state, the one driving wheel determined to be in the abnormal state And a torque limiting means 36 for limiting the output torque of the other drive wheel 2 to a set ratio of output torque with respect to the maximum torque.
The abnormal state is a state incapable of being driven due to abnormality of the motor 6 of the driving wheel 2 or the inverter device 22 that drives the motor 6, overheating of the motor 6 or a power device of the inverter device 22 that drives the motor 6, and the like. .

According to this configuration, the abnormality detection means 34 determines whether any one of the left and

right drive wheels

2 and 2 is in the abnormal state.

When the abnormality detection unit 34 determines that one drive wheel 2 is in the abnormal state and the other drive wheel 2 is not in the abnormal state, that is, is in a normal state, the torque limiting unit 36 is in the abnormal state. The output of a certain drive wheel 2 is stopped, and the output torque of the other drive wheel 2 in a normal state is limited to a set output torque (for example, 50% of the maximum torque) with respect to the maximum torque. This is because if the difference between the output torques of the left and

right drive wheels

2 and 2 is too large, the behavior of the vehicle becomes unstable. In this way, when only one drive wheel 2 is in an abnormal state, the output torque of the normal drive wheel 2 on the opposite side is limited to stabilize the behavior of the vehicle, and then this normal drive wheel 2 makes it possible to evacuate to a road shoulder or a repair shop.

When the maximum torque that can be output from the motor 6 that drives the other driving wheel 2 changes depending on the number of rotations of the motor 6, the torque limiting means 36 outputs a set ratio of output torque to the changed maximum torque. You may restrict to. Generally, in a motor, when the rotation speed exceeds a certain level, the maximum torque of the motor decreases as the motor rotation speed increases. In the case of this configuration, the torque limiter 36 limits the output torque in response to the maximum torque that changes as described above in conjunction with the motor rotation speed that changes from moment to moment, so fine control can be performed. .

The motor 6 includes an in-wheel motor drive including the motor 6, a wheel bearing 4 that rotatably 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 4. The device IWM may be configured.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or 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 present invention.

The present invention will be more clearly understood 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.
1 is a block diagram of a conceptual configuration showing an electric vehicle equipped with a drive control apparatus according to an embodiment of the present invention in a plan view. It is sectional drawing of the in-wheel motor drive device in the same electric vehicle. It is a block diagram of a control system of the drive control device. It is a figure which shows the relationship between a motor rotation speed and output torque. It is a flowchart which shows the process of the drive control apparatus in steps. It is a block diagram of the control system of the drive control apparatus which concerns on other embodiment of this invention.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram of a conceptual configuration showing a plan view of an electric vehicle that is a vehicle equipped with a drive control device according to this embodiment. This electric vehicle has four wheels in which the left and right

rear wheels

2 and 2 of the vehicle body 1 are driving wheels, and the left and right

front wheels

3 and 3 are driven wheels. Car. The

front wheels

3 and 3 are steering wheels. The left and

right wheels

2, 2 as drive wheels are individually driven by

independent traveling motors

6, 6. Each motor 6 constitutes an in-wheel motor drive device IWM described later. Each

wheel

2 and 3 is provided with a brake (not shown).

FIG. 2 is a cross-sectional view of the 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 wheel. 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 the core portion of the rotor 6a. The motor 6 includes a stator 6b that is a fixed side member and a rotor 6a that is a rotation side member. The stator 6 b is fixed to the housing 8, and the rotor 6 a is attached to the rotation output shaft 9. A radial gap is provided between the rotor 6a and the stator 6b.

The control system will be described.
As shown in FIG. 1, the vehicle body 1 includes an accelerator operation unit 16, a brake operation unit 17, and a battery 19. Each of the accelerator operation unit 16 and the brake operation unit 17 includes pedals such as an accelerator pedal and a brake pedal, and a sensor that detects an operation amount of the pedal. 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. The vehicle body 1 is equipped with a drive control device 20 including an ECU 21 and a plurality (two in this example) of inverter devices 22. The ECU 21 is a higher-level control unit that performs overall control of the entire vehicle and gives commands to the inverter devices 22. Each inverter device 22 controls each traveling motor 6 according to a command from the ECU 21. The ECU 21 includes a computer, a program executed by the computer, various electronic circuits, and the like.

ECU21 has the command torque calculating part 47. FIG. The command torque calculation unit 47 mainly uses the accelerator opening signal output from the accelerator operation unit 16 and the deceleration command output from the brake operation unit 17 to drive the

motors

6 and 6 for the left and

right wheels

2 and 2. The acceleration / deceleration command to be given to is generated as a torque value. Further, the ECU 21 has a torque distribution means 48. The torque distribution unit 48 distributes the acceleration / deceleration command calculated by the command torque calculation unit 47 to the traveling

motors

6 and 6 for the left and

right drive wheels

2 and 2 from the steering angle signal output from the steering unit 15. As shown in FIG.

Further, the command torque calculation unit 47 uses a deceleration command value for causing the motor 6 to function as a regenerative brake and a braking torque command value (not shown) when a deceleration command output from the brake operation unit 17 is received. And has the function of distributing to The braking torque command value that causes the motor 6 to function 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.

FIG. 3 is a block diagram of a control system of the drive control device 20. Hereinafter, description will be made with reference to FIG. 1 as appropriate. The inverter device 22 includes a power circuit unit 28 provided for each motor 6 and a motor control unit 29 that controls the power circuit unit 28. The motor control unit 29 has a function of outputting each information related to the in-wheel motor drive device IWM that the motor control unit 29 has to the ECU 21. Information output from the motor control unit 29 to the ECU 21 includes, for example, detection values and control values (status, motor rotation speed, control torque, motor temperature, inverter temperature described later, drive power supply voltage, control power supply voltage, abnormality information). Etc.).

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 (FIG. 1) into three-phase AC power used for driving the motor 6. The inverter 31 is composed of a plurality of semiconductor switching elements (not shown). The PWM driver 32 drives the inverter 31 based on the on / off command. The semiconductor switching element of the inverter 31 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 an acceleration / deceleration command by a torque command or the like given from the ECU 21 which is a host control unit into a current command, performs pulse width modulation, 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 value flowing from the inverter 31 to the motor 6 from the current detection unit 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.

In this embodiment, the abnormality detection means 34 is provided in the motor control unit 29 having the above configuration. The abnormality detection unit 34 determines whether or not the drive wheel 2 driven by the motor 6 corresponding to the inverter device 22 including the abnormality detection unit 34 is in an abnormal state. The abnormal state of the drive wheel 2 refers to the drive wheel due to an abnormality of the motor 6 of the drive wheel 2 or the inverter device 22 that drives the motor 6, overheating of the motor 6 or a power device of the inverter device 22 that drives the motor 6, and the like. This is a state in which driving of 2 is impossible.

In the torque limiting means 36, the abnormality detecting means 34 determines that one of the left driving wheel 2 and the right driving wheel 2 is in the abnormal state, and the other driving wheel 2 is in the normal state. At the same time, the output of the drive wheel 2 in the abnormal state is stopped, and the output torque of the drive wheel 2 in the other normal state is limited to the output torque set to the maximum torque. This is because if the difference between the output torques of the left and

right drive wheels

2 and 2 is too large, the behavior of the vehicle becomes unstable.

FIG. 4 is a diagram showing the relationship between the motor speed and the output torque. In this specification, the “rotational speed” of the motor means the rotational speed of the motor. Generally, in a motor, when the rotation speed exceeds a certain level, the maximum torque of the motor decreases as the motor rotation speed increases. As shown in FIGS. 3 and 4, the torque limiting means 36 is a ratio in which the output torque of the other driving wheel 2 in the normal state is set with respect to the maximum torque when one driving wheel 2 is in the abnormal state. Output torque (for example, 50% of the maximum torque indicated by the dotted line in FIG. 4).

Specifically, in the torque limiting means 36, the command torque output from the torque distribution means 48 to the other drive wheel 2 is, for example, 75% of the maximum torque at the motor rotation speed N1 (FIG. 4 (P1)). In this case, since the output torque of the set ratio (50% of the maximum torque in this example) is exceeded, the command torque to the other drive wheel 2 is limited to 50% of the maximum torque (P2 in FIG. 4). To do.

The torque limiting means 36 takes the command torque as it is when the command torque given from the torque distribution means 48 is, for example, 40% of the maximum torque at the motor rotation speed N2 (P3 in FIG. 4). That is, even if abnormality occurrence information is given from the ECU 21 to the torque limiting means 36 of the other inverter device 22, the command torque given from the torque distribution means 48 to the other inverter device 22 is equal to or less than the set output torque. Does not limit the command torque.

When the left and

right drive wheels

2 and 2 are determined to be in the abnormal state, the torque limiting means 36 controls to stop the output of both the

drive wheels

2 and 2 and stop the vehicle.

For example, if the rotation angle detection means 33 or the current detection means 38 is disconnected or short-circuited, the control itself cannot be performed, so that each torque limiting means 36 stops outputting and the motor 6 cannot be driven. To control. When the motor 6 or the IGBT is overheated, the torque limiting means 36 limits the output torque when the temperature detected by the temperature sensor is equal to or higher than the first threshold, and the output torque when the temperature is higher than the second threshold larger than the first threshold. Set to zero to stop the output. The first and second threshold values are determined based on, for example, results of tests and simulations. When the

inverter devices

22 and 22 are electrically connected with each other between the ECU 21 and the inverter device 22 by a controller area network (abbreviation: CAN) communication, an abnormality in CAN communication (for example, disconnection) When a short circuit occurs, the command does not come, so each torque limiting means 36 stops the output of both wheels.

FIG. 5 is a flowchart showing the processing of the drive control device 20 step by step. This will be described with reference to FIG. For example, this process starts under the condition that the vehicle is powered on, and the abnormality detection unit 34 determines whether each driving wheel 2 is in an abnormal state (step S1). If it is determined that there is no abnormality in both drive wheels (step S1: No), this process is terminated. If it is determined that at least one of the drive wheels 2 is in an abnormal state (step S1: Yes), the process proceeds to step S2.

Next, the ECU 21 determines whether only one of the left and

right drive wheels

2, 2 is in an abnormal state or whether both wheels are in an abnormal state (step S2), and only one of the left and

right drive wheels

2, 2 is in an abnormal state. At a certain time, the torque limiting means 36 stops the output of the driving wheel 2 in the abnormal state and limits the output torque of the driving wheel 2 in the normal state to a set value according to the motor rotation speed (step S3). Thereafter, this process is terminated.
If it is determined in step S2 that both wheels are in an abnormal state, each torque limiting means 36 controls to stop the output of both drive wheels 2 and stop the vehicle (step S4). Thereafter, this process is terminated.

According to the vehicle drive control apparatus described above, when the abnormality detection means 34 determines that only one drive wheel 2 is in the abnormal state and the other drive wheel 2 is in the normal state, the torque limiting means 36 The output of one drive wheel 2 in the abnormal state is stopped, and the output torque of the other drive wheel 2 in the normal state is limited to the output torque set to the maximum torque. Thus, when one drive wheel 2 becomes abnormal, the output torque of the other normal drive wheel 2 is limited to stabilize the behavior of the vehicle. You can evacuate to the shoulder or repair shop.

When the maximum torque that can be output from the motor 6 that drives the normal driving wheel 2 changes depending on the motor rotation speed, the torque limiting means 36 limits the output torque to a set ratio with respect to the changed maximum torque. Therefore, since the torque limiting means 36 limits the output torque in conjunction with the motor rotational speed that changes from moment to moment, fine control can be performed.

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

In the above embodiment, the two inverter devices are provided separately. However, as shown in FIG. 6, the inverter devices 22 that respectively control the motors 6 may be integrated. In this case, the torque limiting means 36 is provided in the inverter device 22. According to the configuration shown in FIG. 6, it is possible to simplify the cables and connectors as compared with the configuration shown in FIG.

The weak electrical system of each inverter device 22 may be constituted by a common computer or an electronic circuit on a common substrate.
As the vehicle, a two-wheel independent drive vehicle that independently drives the left and right front wheels may be applied. 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 ... wheel (drive wheel)
DESCRIPTION OF SYMBOLS 4 ... Wheel bearing 6 ... Motor 7 ... Reduction gear 34 ... Abnormality detection means 36 ... Torque limitation means IWM ... In-wheel motor drive device

Claims

A drive control device that controls driving of a vehicle including two motors that individually drive a left driving wheel and a right driving wheel,
An abnormality detection means for determining whether one of the left driving wheel and the right driving wheel is in an abnormal state;
When the abnormality detecting means determines that one of the left driving wheel and the right driving wheel is in the abnormal state, the output of the one driving wheel determined to be in the abnormal state is stopped. A torque limiting means for limiting the output torque of the other drive wheel to a set ratio of output torque with respect to the maximum torque;
A wheel independent drive type vehicle drive control device.
2. The drive control device according to claim 1, wherein when the maximum torque that can be output from the motor that drives the other drive wheel changes depending on the number of rotations of the motor, A drive control device for a wheel independent drive type vehicle that limits the output torque to a set ratio.
3. The drive control device according to claim 1, wherein the motor includes the motor, a wheel bearing that rotatably supports the driving wheel, and a speed reducer that decelerates the rotation of the motor and transmits the rotation to the wheel bearing. The wheel independent drive type vehicle drive control apparatus which comprises the in-wheel motor drive device containing this.