JP2016052164A - Drive control device of wheel independent drive type vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, in a drive control device of a vehicle having right and left motors individually driving right and left drive wheels, the drive control device of the wheel independent drive type vehicle, which enables evacuation travel to a road shoulder or the like when one of the drive wheels becomes an abnormal condition.SOLUTION: A drive control device of a vehicle comprises right and left motors individually driving right and left drive wheels. There are provided an abnormality detection means detecting whether or not either one of the right and left drive wheels is in an abnormal condition; and a torque limit means, when either one of the right and left drive wheels is determined by the abnormality detection means to be in the abnormal condition, stopping output of the drive wheel and limiting output torque of the other drive wheel to the output torque of a ratio set relative to the maximum torque.SELECTED DRAWING: Figure 1

Description

  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 wheel side in the turning direction becomes unable to drive, the driving force for the front wheel on the inner wheel 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 wheel independent drive type vehicle drive control device according to the present invention is a vehicle drive control device including left and right motors 6 and 6 for individually driving left and right drive wheels 2 and 2,
An abnormality detection means 34 for detecting whether the left and right drive wheels 2, 2 are in an abnormal state;
When any one of the left and right drive wheels 2, 2 is in the abnormal state by the abnormality detection means 34, the output of the drive wheel is stopped and the output torque of the other drive wheel 2 is maximized. Torque limiting means 36 for limiting the output torque to a set ratio with respect to the torque is provided.
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 driving wheels 2 and 2 is in the abnormal state.

  When it is determined by the abnormality detection means 34 that one drive wheel 2 is in the abnormal state and the other drive wheel 2 is not in the abnormal state, that is, in the normal state, the torque limiting means 36 is in the abnormal state. The output of the drive wheel 2 is stopped, and the output torque of the drive wheel 2 in the other normal state is limited to an output torque (for example, 50% of the maximum torque) set to the maximum torque. This is because if the output torques of the left and right drive wheels 2 and 2 are too different, the behavior of the vehicle becomes unstable. In this way, when one of the wheels becomes abnormal, the output torque of the normal driving wheel 2 on the opposite side is limited to stabilize the behavior of the vehicle. Or evacuate to 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.

  The drive control device for a wheel independent drive vehicle according to the present invention is a vehicle drive control device including left and right motors for individually driving left and right drive wheels, and one of the left and right drive wheels is in an abnormal state. And an abnormality detection means for detecting whether or not any one of the left and right drive wheels is in the abnormal state by the abnormality detection means, and stops the output of the drive wheel and outputs torque of the other drive wheel Torque limiting means for limiting the output torque to a ratio of the output torque set to the maximum torque. For this reason, in a vehicle drive control device that includes left and right motors that individually drive the left and right drive wheels, when one of the drive wheels is in an abnormal state, it is possible to retreat to the road shoulder or the like. .

It is a block diagram of the conceptual composition which shows the electric vehicle carrying the drive control device concerning the embodiment of this invention with a top 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 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 front wheel 3 is a steering wheel. The left and right wheels 2 and 2 serving as driving wheels are driven by independent traveling motors 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. 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.

The control system will be described.
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 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.

  The ECU 21 has a command torque calculation unit 47. 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. 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.

  The command torque calculation unit 47 distributes the braking torque command value for causing the motor 6 to function as a regenerative brake and the braking torque command value (not shown) when there is a deceleration command output from the brake operation unit 17. Have The 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 each traveling motor 6, 6. 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.

  FIG. 3 is a block diagram of a control system of this drive control device. 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 information (eg, status, motor speed, control torque, motor temperature, inverter temperature described later) such as detection values and control values related to the in-wheel motor drive device IWM of the motor control unit 29. , 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), and the PWM driver 32 drives the inverter 31 based on an on / off command. 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 detection means 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 following 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 is a state in which driving is impossible 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 the power device of the inverter device 22 that drives the motor 6, and the like. .

  When the torque limiting means 36 determines that one of the left and right driving wheels 2 is in the abnormal state and the other driving wheel 2 is in the normal state, the torque limiting means 36 sets the abnormal driving wheel 2 in the abnormal state. While stopping the output, the output torque of the drive wheel 2 in the other normal state is limited to the output torque of the ratio set with respect to the maximum torque. This is because if the output torques of the left and right drive wheels 2 and 2 are too different, the behavior of the vehicle becomes unstable.

  FIG. 4 is a diagram showing the relationship between the motor speed and the output torque. 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 outputs the output torque of the drive wheel 2 in the other normal state at a ratio set with respect to the maximum torque (for example, indicated by a dotted line in FIG. 4). To 50% of the maximum torque).

  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.

  For example, when the command torque given from the torque distribution means 48 is 40% of the maximum torque at the motor rotation speed N2 (P3 in FIG. 4), the torque limiting means 36 uses the command torque as it is. 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 it is determined that both the left and right drive wheels 2 and 2 are 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, when 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 control 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 between the ECU 21 and the inverter device 22 by controller area network (abbreviation: CAN) communication, abnormality in CAN communication (for example, disconnection) , Short, etc.), the command does not come, so each torque control means 36 stops the output of both wheels.

  FIG. 5 is a flowchart showing the processing of this drive control apparatus 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 any one of the drive wheels 2 is determined to be in an abnormal state (step S1: Yes), the process proceeds to step S2.

Next, the ECU 21 determines whether only one wheel is in an abnormal state or both wheels are in an abnormal state (step S2). When only one wheel is in an abnormal state, the torque limiting means 36 drives the abnormal state. The output of the wheel 2 is stopped, and the output torque of the drive wheel 2 in a normal state is limited to a set value corresponding 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 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 the driving wheel 2 in the state is stopped, and the output torque of the driving wheel 2 in the other normal state is limited to the output torque of the ratio set with respect to the maximum torque. In this way, when one of the wheels becomes abnormal, the output torque of the normal driving wheel 2 on the opposite side is limited to stabilize the behavior of the vehicle. Or evacuate to a repair shop.

  When the maximum torque that can be output from the motor 6 that drives the normal drive wheel 2 changes depending on the motor rotation speed, the torque limiting unit 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. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination does not hinder the combination.

  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.

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 (3)

In a vehicle drive control device including left and right motors for individually driving left and right drive wheels,
An abnormality detection means for determining whether one of the left and right drive wheels is in an abnormal state;
When any one of the left and right drive wheels is in the abnormal state by the abnormality detection means, the output of the drive wheel is stopped and the output torque of the other drive wheel is set to the maximum torque. Torque limiting means for limiting the output torque to
A drive control device for a wheel independent drive type vehicle, comprising:   2. The vehicle drive control device according to claim 1, wherein when the maximum torque that can be output by a motor that drives the other driving wheel changes depending on the number of rotations of the motor, the torque limiting unit changes the maximum torque. The wheel independent drive type vehicle drive control device that limits the output torque to a set ratio.   3. The vehicle drive control device according to claim 1, wherein the motor includes the motor, a wheel bearing that rotatably supports the drive wheel, and the rotation of the motor is decelerated and transmitted to the wheel bearing. A drive control device for a wheel independent drive type vehicle constituting an in-wheel motor drive device including a reduction gear.

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