KR20140060872A - Four-wheel drive system of vehicle and method for synchronizing speed of the same - Google Patents

Abstract

An embodiment of the present invention relates to a four-wheel drive system and a method for synchronizing speed thereof. Technical problems to solve is to reduce rotational resistance by the driving motor of a motor-driven four-wheel drive vehicle in a region of the driving motor not being used, to minimize a shock to the vehicle that can be generated when a power separating device is operated, and to improve the combination performance of the power separating device. For the purpose, the four-wheel drive system of a vehicle according to an embodiment of the present invention comprises: a front-wheel drive module and a rear-wheel drive module. The rear-wheel drive module includes: an upper control part for determining the torque of the driving motor after judging whether or not rear wheels are driving on the basis of driving information of the vehicle when the front-wheel drive module is operated; a driving motor controlling part for controlling the drive of the driving motor after receiving the torque of the driving motor determined by the upper control part, and detecting and transmitting the speed and position data of the rotor of the driving motor to the upper control part; and a power separating part for transmitting the torque of the driving motor, which has been transmitted from the driving motor controlling part, to a wheel by connecting the output side of a decelerator, which is arranged between the driving motor and the wheel to decelerate the rotational speed of the wheel, to the wheel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a four-

One embodiment of the present invention relates to a vehicle four-wheel drive apparatus and a speed synchronization method thereof.

Unlike a usual two-wheel drive (2WD) type vehicle, a four-wheel drive device is a device that can use all the front and rear wheels of a vehicle at all times or, if necessary, as a drive wheel. Power is transmitted to all four wheels, Compared to the two-wheel drive system, the propulsion system is superior to the two-wheel drive system, which improves stability and safety when traveling on slippery roads and rough roads.

However, since the power output from the engine of the conventional four-wheel drive apparatus is distributed to the front and rear wheels through a transfer case by mechanical connection, power loss occurs and an additional mechanical power transmission device is required There is a problem that the weight of the vehicle is increased. In particular, there is a problem that the power transmission by the mechanical method is difficult to precisely control.

In one embodiment of the present invention, in the motor-driven four-wheel drive vehicle, the rotational resistance by the drive motor in the unused area of the drive motor is reduced, the impact of the vehicle that may occur when the power separation device is operated is minimized, The present invention provides a vehicle four-wheel drive apparatus and a speed synchronization method therefor.

The four-wheel drive apparatus according to an embodiment of the present invention is a vehicle four-wheel drive apparatus having a front wheel drive module and a rear wheel drive module, wherein the rear wheel drive module determines whether the rear wheel drive And determines a torque amount of the driving motor; A drive motor control unit that receives the torque amount of the drive motor determined by the upper control unit and controls the drive of the drive motor, and senses the speed and position data of the rotor of the drive motor and transmits it to the upper control unit; And a power split unit that is provided between the drive motor and the wheel and connects the output side of the speed reducer that reduces the rotation speed of the wheel to the wheel and transmits the torque amount of the drive motor transmitted from the drive motor control unit to the wheel can do.

A resolver is provided between the driving motor control unit and the driving motor to sense speed and position data of the rotor of the driving motor.

The power split unit includes a position sensor, and the position sensor senses the position of the power split unit and transmits the sensed position to the upper control unit. The upper control unit controls the position of the power split unit, Whether or not the wheels are engaged can be determined.

The high-level control unit generates at least one control mode according to the driving state of the vehicle, and the driving-motor control unit may apply a current according to the torque amount corresponding to the control mode to the driving motor.

The upper control unit receives the speed and position data of the rotor of the drive motor from the resolver and can control the torque amount of the drive motor.

The upper control unit may release the connection between the output side of the speed reducer and the wheel through the drive motor control unit when it is determined that the rear wheel drive is not necessary.

The running information of the vehicle may include the speed of the wheel and the rotational speed of the driving motor.

A rear wheel drive determination unit for determining whether the rear wheels are driven based on the travel information of the vehicle; A torque calculating unit for calculating a torque amount of the driving motor required for the rear wheel drive; A connection state determiner for determining a connection state between the output side of the speed reducer and the wheel; A speed calculating unit for calculating an output side rotational speed of the speed reducer and a relative rotational speed of the output side of the speed reducer to the speed of the wheel from the speed of the wheel and the rotational speed of the driving motor; A determining unit for determining whether the relative rotational speed is within a permissible speed between the output side of the speed reducer and the wheel; And when the relative rotation speed is within a permissible coupling speed between the output side of the speed reducer and the wheel, engages the output side of the speed reducer and the wheel, and when the relative speed is other than the engageable speed between the output side of the speed reducer and the wheel, And a power separation control unit for releasing the output side of the wheel and the wheel.

The high-level control unit may further include a motor driving unit for controlling an operation of the driving motor based on the output of the power separation control unit.

In another aspect of the present invention, there is provided a speed synchronization method for a vehicle four-wheel drive apparatus, the method including: a first step of determining whether the rear wheels are driven based on driving information of the vehicle when the front wheel drive module is driven; A second step of calculating a first torque amount of the driving motor required for the rear wheel drive; A third step of operating the drive motor based on a first torque amount of the drive motor; A fourth step of calculating an output side rotational speed of the speed reducer based on the speed of the drive motor and a relative rotational speed of the speed reducer output side with respect to the wheel speed; A fifth step of determining whether the relative rotational speed is within a permissible speed between the output side of the speed reducer and the wheel; A sixth step of coupling the output side of the speed reducer and the wheel when the relative rotation speed is within an engageable speed between the output side of the speed reducer and the wheel; A seventh step of calculating a second torque amount of the driving motor required for driving the rear wheels based on the wheel speed and the rotational speed of the driving motor; And an eighth step of operating the drive motor based on the second torque amount of the drive motor.

The running information of the vehicle may include the speed of the wheel and the rotational speed of the driving motor.

The first torque amount in the second step may be calculated based on the wheel speed and the gear ratio of the speed reducer.

Between the sixth step and the seventh step, a coupling completion signal is detected between the output side of the speed reducer and the wheel; And a sixth step of controlling the driving motor so that the torque amount becomes zero for a predetermined time.

After the eighth step, it may further include a ninth step of determining whether to release the rear wheel drive based on the running information of the vehicle.

After the ninth step, the controller may further include a tenth step of controlling the driving motor so that the torque amount becomes zero for a predetermined time.

After the tenth step, an eleventh step of releasing the coupling between the output side of the speed reducer and the wheel may be further included.

A twelfth step of detecting a release completion signal between the output side of the speed reducer and the wheel after the eleventh step; And a thirteenth step of controlling the driving motor so that the amount of torque is zero for a predetermined time.

The method may further include a seventh step of controlling the torque of the driving motor to be zero to stop the driving motor.

The step 14 may be continued until the rotational speed of the driving motor is stopped.

Further, another embodiment of the present invention is also applicable to a computer-readable recording medium on which a program for executing a velocity synchronization method of a vehicle four-wheel drive apparatus is recorded.

The vehicle four-wheel drive apparatus and the speed synchronization method thereof according to the embodiment of the present invention can reduce the rotational resistance caused by the drive motor in the unused region of the drive motor in the motor-driven four-wheel drive vehicle and can occur when the power- It is possible to minimize the impact of the vehicle and improve the coupling performance of the power splitting device.

1 is a view schematically showing a motor-driven four-wheel drive vehicle including a four-wheel drive vehicle for a vehicle according to an embodiment of the present invention.
2 is a block diagram briefly showing a vehicle four-wheel drive apparatus according to an embodiment of the present invention.
3 is a block diagram showing the upper control unit of Fig.
4 is a flowchart showing a speed synchronization method using a four-wheel drive apparatus for a vehicle according to another embodiment of the present invention.
5 is a flowchart briefly showing a control procedure for each configuration in the speed synchronization method of FIG.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which those skilled in the art can readily implement the present invention.

Fig. 1 is a schematic view of a motor-driven four-wheel drive vehicle including a four-wheel drive vehicle for a vehicle according to an embodiment of the present invention, and Fig. 2 is a block diagram schematically showing a four- FIG. 3 is a block diagram showing the upper control unit of FIG. 2. FIG.

Referring to FIG. 1, a motor-driven four-wheel-drive vehicle 10 includes a front wheel drive module 110 and a rear wheel drive module 120. That is, the motor-driven four-wheel drive vehicle 10 is a three-phase (three-phase) vehicle in which front wheels can independently generate separate driving forces on the rear wheel side in the front wheel drive vehicle 10 on which the internal combustion engine 111 and the transmission 113 are mounted. Driven vehicle 10 to which a drive motor (hereinafter referred to as a drive motor 125) and a power transmission portion (hereinafter referred to as a power separation portion 123) are mounted. In other words, the motor-driven four-wheel-drive vehicle 10 is also referred to as an e4WD system, and is configured by using the current generated by the generator 112 mounted on the output side of the engine 111 of the front wheel drive module 110, And drives the driving motor 125 mounted on the main body 120. Hereinafter, the motor-driven four-wheel drive vehicle 10 will be referred to as a four-wheel drive vehicle for a vehicle. However, the motor-driven four-wheel drive vehicle 10 is not limited to the four- Concept.

The front wheel drive module includes an engine 111, a generator 112, a transmission 113, a high voltage battery 114, and a power converter 115.

The engine 111 is connected to the transmission 113 to drive the front axle of the vehicle and is connected to the generator 112 to generate current.

The generator 112 is connected to the output side of the engine 111 by a power transmission means such as a belt, a chain, or a gear to generate a current.

The high-voltage battery 114 is connected to the generator 112 and is charged with a generated current.

The power converter 115 is connected to a high voltage battery and receives a charged current to control a current supplied to the driving motor 125.

2, the rear wheel drive module 120 includes an upper control unit 121, a driving motor control unit 122, a power separation unit 123, a speed reducer 124, and a driving motor 125.

The front wheel drive module 110 and the rear wheel drive module 120 of the vehicle 10 are provided with speed detectors (not shown) for detecting respective speeds. A drive motor 125 is mounted on the output side of the drive motor 125, (Not shown) for detecting the number of revolutions of the motor.

The upper control unit 121 determines the optimal running torque of the rear wheel by determining the driving state of the vehicle, and applies the command to the driving motor control unit 122 and controls the operation of the power splitting unit 123. The upper controller 121 determines whether or not the rear wheel drive module 120 needs to be driven based on the running information of the vehicle when the front wheel drive module 110 is driven and determines the torque amount of the driving motor 125. Here, the traveling information of the vehicle includes the speed of the front / rear wheels, the driving speed of the driving motor 125, and the like. The upper control unit 121 can generate at least one control mode according to the driving state of the vehicle and allows the driving motor control unit 122 to apply a current corresponding to the torque amount corresponding to the control mode to the driving motor 125 . The upper control unit 121 receives the speed and position data of the rotor of the drive motor 125 from the resolver 126 and can control the torque amount of the drive motor 125. [ If it is determined that rear wheel drive is not required, the upper controller 121 may disconnect the output side of the speed reducer 124 and the wheel 128 via the drive motor controller 122. [

3, the upper control unit 121 includes a rear wheel drive determination unit 121a, a torque calculation unit 121b, a connection state determination unit 121c, a speed calculation unit 121d, a coupling possibility determination unit 121e, And a power separation control unit 121f.

The rear wheel drive determination unit 121a determines whether the rear wheels are driven based on the running information of the vehicle.

The torque calculating section 121b calculates a torque amount of the driving motor 125 necessary for rear wheel drive.

The connection state determination unit 121c determines the connection state between the output side of the speed reducer 124 and the wheel 128. [

The speed calculator 121d calculates the relative speed of the output side rotation speed of the speed reducer 124 from the speed of the wheel 128 and the rotation speed of the driving motor 125 and the relative rotation speed of the output side of the speed reducer 124 to the speed of the wheel 128 Calculate the speed.

Whether or not the relative rotation speed of the output side of the speed reducer 124 with respect to the speed of the wheel 128 is within a permissible speed between the output side of the speed reducer 124 and the wheel 128 do.

When the relative rotation speed of the output side of the speed reducer 124 with respect to the speed of the wheel 128 is within a permissible speed between the output side of the speed reducer 124 and the wheel 128, the power separation control unit 121f controls the speed reducer 124, And releases the engagement between the output side of the speed reducer 124 and the wheel 128 when the speed of the output of the speed reducer 124 and the wheel 128 are other than the permissible speed between the output side of the speed reducer 124 and the wheel 128.

The driving motor control unit 122 is connected to the upper control unit 121 and receives the torque amount of the driving motor 125 determined by the upper control unit 121. The driving motor control unit 122 is connected to the power converter 115, And controls the driving of the driving motor 125 using the current supplied by the driving motor 125. The driving motor control unit 122 senses the speed and position data of the rotor of the driving motor 125 through the resolver 126 and transmits it to the upper control unit 121.

The drive motor control unit 122 receives a control mode (speed control, zero torque control, uncontrolled power generation mode) received from the upper level control unit 121 and receives a control amount (target speed, target torque, And applies a proper current to the driving motor 125. The speed and position of the rotor are fed back from the resolver 126 to perform torque control and speed control and the resultant value is supplied to the upper controller 121 Retransmission.

Although not shown, the upper controller 121 may further include a motor driver for controlling the operation of the drive motor 125 by the output of the power split controller 121f.

The power separation unit 123 is provided between the driving motor 125 and the wheel 128 to connect the output side of the speed reducer 124 that decelerates the rotation speed of the wheel 128 and the wheel 128, The control unit 122 transmits the torque of the driving motor 125 to the wheel 128 to operate the rear wheel drive module 120.

A position sensor 127 is provided on one side of the power splitter 123. The position sensor 127 senses the position of the power splitter 123 and transmits the sensed power to the upper controller 121, The control unit 121 can determine whether or not the output side of the speed reducer 124 and the wheel 128 are coupled by the detected power split unit 123. [

In order to transmit the torque amount of the drive motor 125 to the wheel 128, the output side of the speed reducer 124 and the wheel 128 must be connected by the power separation unit 123, When the driving force of the driving motor 125 is not required, the output side of the speed reducer 124 and the wheel 128 are separated by the power separating unit 123 so that the running resistance of the vehicle due to the rotational load of the driving motor 125 can be minimized And the drive motor 125 is driven to rotate to the limit speed of the drive motor 125 to prevent the drive motor 125 and the drive motor control unit 122 from being burned. In other words, depending on the case, the power splitting unit 123 may repeatedly perform engagement and disengagement during traveling of the vehicle, but can not perform engagement in a state where the speed difference between the wheel speed and the output side of the speed reducer 124 is large, The power splitter may be damaged or a large noise and impact may occur.

In order to prevent such a phenomenon in the present invention, the upper controller 121 and the driving motor controller 122 can perform coupling and disengagement safely and quickly according to the procedure shown in FIG. 4. In order to perform the control as shown in FIG. 4 The upper control unit 121 may be controlled as shown in FIG.

FIG. 4 is a flowchart showing a speed synchronization method using a four-wheel drive apparatus for a vehicle according to another embodiment of the present invention, and FIG. 5 is a flowchart briefly showing a control procedure for each configuration in the speed synchronization method of FIG.

Fig. 4 shows a control method when the initial position of the power splitting section is in the release state.

Four-wheel drive event detection step (first step)

The first step determines whether the rear wheels are driven based on the running information of the vehicle when the front wheel drive module is driven (S1) (S2). That is, in the first step, it is determined whether a necessary event of the rear wheel drive force is generated (S2).

Speed synchronization step (second to fourth steps)

In the first step, when the necessary event of the rear wheel drive force is generated, a second step of calculating the first torque amount is performed for the speed control (S3) of the drive motor necessary for the rear wheel drive. Then, a third step of operating the drive motor based on the first torque amount of the drive motor is performed. That is, in the third step, the upper control unit transmits the speed control command to the driving motor control unit based on the first torque amount of the driving motor. At this time, the speed control demand amount (rpm) of the drive motor is calculated from the wheel speed (rpm) by reflecting the gear ratio of the speed reducer. Then, a fourth step of calculating the relative rotation speed of the reduction gear output side with respect to the wheel rotation speed and the output rotation speed of the reduction gear from the speed of the drive motor is performed (S5). Wherein the upper control section receives the actual rotation speed of the drive motor output from the resolver of the drive motor by the upper control section and determines the rotation speed of the reduction gear output side from the received drive motor speed and the relative speed between the wheel speed and the reduction gear output side .

power Separating portion  Operation steps (fifth to sixth steps)

A fifth step of determining whether the relative rotation speed of the reduction gear output side with respect to the wheel speed calculated in the fourth step is within a permissible speed between the output side of the reduction gear and the wheel (S5). Then, if the relative rotation speed of the reduction gear output side with respect to the wheel speed is within a permissible coupling speed between the output side of the reduction gear and the wheel, a sixth step of coupling the output side of the reduction gear and the wheel is performed (S6). That is, it is determined whether the relative speed is within a permissible speed in the fifth step. In the sixth step, when the relative speed is within the permissible speed, the motor M of the power separating part is operated to connect between the output side of the speed reducer and the wheel In the coupling direction. Then, the upper control unit detects the engagement completion signal from the position sensor of the power split unit (S7).

Torque control step

Then, the high-level control unit sends a zero-torque control request command to the drive motor control unit side to reduce the impact due to the sudden change of the control mode. The drive motor control unit controls the torque control S8 so that the torque applied to the drive motor becomes zero. . At this time, the torque control is performed in such a manner as to maintain a zero torque for a predetermined period of time.

4 WD  Torque control step

A fourth step of calculating a second torque amount to control the 4WD torque of the drive motor required for rear wheel drive based on the wheel speed and the rotation speed of the drive motor; The operation of the drive motor is performed in an eighth step. That is, in the seventh and eighth steps, the rear wheel driving force is calculated according to the state of the vehicle, and the required torque is transmitted to the driving motor control unit to operate the driving motor according to the required torque.

Fourth-wheel drive event releasing step (ninth step)

Further, it is possible to go through a ninth step of determining whether the rear wheel drive is released based on the running information of the vehicle while the vehicle is running (S10). That is, the ninth step determines whether or not an unnecessary event of the rear wheel drive force occurs, that is, whether the rear wheel drive condition is released.

Torque control step (tenth step)

Then, when it is determined that the rear wheel drive condition is released, a tenth step of controlling the drive motor so that the torque amount becomes zero for a predetermined time is performed. In the tenth step, when the power separating unit is disconnected immediately in the torque control state, since the drive motor can rapidly increase from the release completion time to the no-load state to maintain the required torque amount, the upper control unit keeps the torque control amount at 0 (S11). At this time, the torque control is performed in such a manner as to maintain a zero torque for a predetermined period of time.

Operation steps of the power splitter (steps 11 to 12)

Then, the eleventh step of releasing the coupling between the output side of the speed reducer and the wheel is performed. That is, in the eleventh step, the power separation unit is operated in the release direction (S12) to release the coupling between the output side of the speed reducer and the wheel. Then, the high-level control unit performs a twelfth step of detecting a release completion signal from the position sensor of the power split unit (S13).

The speed control step (steps 13 to 14)

Thereafter, a control is performed in the thirteenth step of controlling the drive motor so that the amount of torque is zero for a predetermined time (S14). That is, the thirteenth step controls the upper control unit to transmit a speed control request command to the driving motor control unit to stop the driving motor. In order to stop the drive motor, the torque of the drive motor is controlled to be zero. In order to prevent burn-out due to the sudden stop of the motor, the 14th step sends the required speed to the driving motor control unit side to 0 through a predetermined time. In this case, the step 14 is maintained until the rotational speed of the driving motor inputted from the resolver of the driving motor is completely stopped.

Drive motor is not driven

Then, the high-level control unit releases the control mode of the driving motor control unit until the rear wheel drive event is detected again (S15) and maintains the ready state.

According to the speed synchronization method of the four-wheel drive as described above, it is possible to minimize the running resistance due to the forced rotation of the drive motor in the motor-driven four-wheel drive vehicle 10 under the conditions of the rear- It is possible to originally block the rotation speed from reaching the limit speed. Further, according to the speed synchronization method of the present four-wheel drive apparatus, by controlling the speed synchronization control and the zero torque control in accordance with procedures, it is possible to prevent the shock transmitted to the vehicle due to engagement and disengagement of the power split portion, Noise can be minimized, and the possibility of burn-out of the power splitter and the reducer can be minimized.

Meanwhile, the speed synchronization method of the above-described four-wheel drive apparatus may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable recording medium. The recording medium may include program commands, data files, data structures, and the like, alone or in combination. Program instructions to be recorded on a recording medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. For example, the recording medium may be a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical medium such as a CDROM or a DVD, a magneto-optical medium such as a floptical disk, magneto-optical media, and hardware devices configured to store and perform program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. Such a hardware device may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention is not limited to the above-described embodiment, but can be applied to a four-wheel drive apparatus and a speed synchronization method according to the present invention, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

10: four-wheel drive vehicle 110: front wheel drive module
111: engine 112: generator
113: Transmission 114: High-voltage battery
115: power converter 120: rear wheel drive module
121: upper control unit 121a: rear wheel drive determination unit
121b: torque calculating unit 121c: connection state judging unit
121d: Speed calculation unit 121e:
121f: power separation control section 122: drive motor control section
123: Power separation unit 124: Reduction gear
125: drive motor 126: resolver
127: Position sensor 128: Wheel

Claims (22)

A four-wheel drive apparatus for a vehicle comprising a front wheel drive module and a rear wheel drive module,
The rear wheel drive module
An upper control unit for determining whether a rear wheel is driven based on driving information of the vehicle when the front wheel drive module is driven to determine a torque amount of the driving motor;
A drive motor control unit that receives the torque amount of the drive motor determined by the upper control unit and controls the drive of the drive motor, and senses the speed and position data of the rotor of the drive motor and transmits it to the upper control unit; And
And a power split unit that is provided between the drive motor and the wheel and connects the output side of the speed reducer that reduces the rotation speed of the wheel to the wheel and transmits the torque amount of the drive motor transmitted from the drive motor control unit to the wheel And the vehicle is driven by the vehicle. The method according to claim 1,
And a resolver is provided between the driving motor control unit and the driving motor to sense speed and position data of the rotor of the driving motor. The method according to claim 1,
A position sensor is provided on one side of the power split unit,
The position sensor senses the position of the power split unit and transmits the sensed position to the upper control unit,
And the upper control unit determines whether or not the output side of the speed reducer and the wheel are engaged by the detected position of the power split unit. The method according to claim 1,
Wherein the upper control unit generates at least one control mode according to the running state of the vehicle,
And the drive motor control unit applies a current corresponding to the amount of torque corresponding to the control mode to the drive motor. 3. The method of claim 2,
Wherein the upper control unit receives the speed and position data of the rotor of the drive motor from the resolver and controls the torque amount of the drive motor. The method according to claim 1,
Wherein the upper control unit releases the connection between the output side of the speed reducer and the wheel via the drive motor control unit when it is determined that rear wheel drive is not necessary. The method according to claim 1,
Wherein the running information of the vehicle includes the speed of the wheel and the rotational speed of the driving motor. The method according to claim 1,
The high-
A rear wheel drive determination unit for determining whether the rear wheels are driven based on travel information of the vehicle;
A torque calculating unit for calculating a torque amount of the driving motor required for the rear wheel drive;
A connection state determiner for determining a connection state between the output side of the speed reducer and the wheel;
A speed calculating unit for calculating an output side rotational speed of the speed reducer and a relative rotational speed of the output side of the speed reducer to the speed of the wheel from the speed of the wheel and the rotational speed of the driving motor;
A determining unit for determining whether the relative rotational speed is within a permissible speed between the output side of the speed reducer and the wheel; And
When the relative rotation speed is within a permissible coupling speed between the output side of the speed reducer and the wheel, engages the output side of the speed reducer with the wheel, and when the relative rotation speed is other than the engageable speed between the output side of the speed reducer and the wheel, And a power separation control unit for releasing between the output side and the wheel. 9. The method of claim 8,
Wherein the upper control unit further comprises a motor driving unit for controlling an operation of the driving motor by an output of the power split control unit. 10. A speed synchronization method for a vehicle four-wheel drive apparatus according to any one of claims 1 to 9,
A first step of determining whether the rear wheels are driven based on driving information of the vehicle when the front wheel drive module is driven;
A second step of calculating a first torque amount of the driving motor required for the rear wheel drive;
A third step of operating the drive motor based on a first torque amount of the drive motor;
A fourth step of calculating an output side rotational speed of the speed reducer based on the speed of the drive motor and a relative rotational speed of the speed reducer output side with respect to the wheel speed;
A fifth step of determining whether the relative rotational speed is within a permissible speed between the output side of the speed reducer and the wheel;
A sixth step of coupling the output side of the speed reducer and the wheel when the relative rotation speed is within an engageable speed between the output side of the speed reducer and the wheel;
A seventh step of calculating a second torque amount of the driving motor required for driving the rear wheels based on the wheel speed and the rotational speed of the driving motor; And
And an eighth step of operating the drive motor based on a second torque amount of the drive motor. 11. The method of claim 10,
Wherein the running information of the vehicle includes the speed of the wheel and the rotational speed of the drive motor. 11. The method of claim 10,
Wherein the first torque amount in the second step is calculated on the basis of the wheel speed and the gear ratio of the speed reducer. 13. The method of claim 12,
Between the sixth step and the seventh step,
Further comprising a sixth step of detecting an engagement completion signal between the output side of the speed reducer and the wheel. 14. The method of claim 13,
Between steps 6-1 and 7,
Further comprising a sixth step (6-2) of controlling the drive motor so that the torque amount becomes 0 for a predetermined time. 11. The method of claim 10,
After the eighth step,
Further comprising a ninth step of determining whether to release the rear wheel drive based on the running information of the vehicle. 16. The method of claim 15,
After the ninth step,
Further comprising a tenth step of controlling the driving motor so that the torque amount becomes 0 for a predetermined time period. 17. The method of claim 16,
After the tenth step,
And canceling the coupling between the output side of the speed reducer and the wheel. 18. The method of claim 17,
After the eleventh step,
And a twelfth step of detecting a release completion signal between the output side of the speed reducer and the wheel. 19. The method of claim 18,
After the step 12,
Further comprising a thirteenth step of controlling the drive motor so that the torque amount becomes 0 for a predetermined time. 20. The method of claim 19,
After step 13,
Further comprising a 14th step of controlling the torque amount of the drive motor to 0 in order to stop the drive motor. 21. The method of claim 20,
And the step (14) is continued until the rotational speed of the drive motor is stopped. A computer-readable recording medium having recorded thereon a program for executing a velocity synchronization method for a vehicle's four-wheel drive apparatus according to any one of claims 10 to 21.

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