阅读说明：本技术 车辆座椅的折叠控制装置及控制方法 (Folding control device and control method for vehicle seat ) 是由 李晋雨 于 2020-11-20 设计创作，主要内容包括：本发明的一个实施例涉及一种车辆座椅的折叠控制装置及控制方法,车辆座椅的折叠控制装置用于控制第一车辆座椅和第二车辆座椅的折叠或展开,并且包括：第一电机,产生用于折叠第一车辆座椅的驱动力；第二电机,产生用于折叠第二车辆座椅的驱动力；第一传感器,检测所述第一电机的旋转速度和旋转量中的至少一个；第二传感器,检测所述第二电机的旋转速度和旋转量中的至少一个；以及至少一个控制模块,基于所述第一传感器和所述第二传感器的检测结果,控制第一电机和第二电机中的至少一个,所述控制模块通过控制占空比来控制所述第一电机和所述第二电机中的至少一个。(One embodiment of the present invention relates to a folding control device of a vehicle seat for controlling folding or unfolding of a first vehicle seat and a second vehicle seat, and includes: a first motor that generates a driving force for folding the first vehicle seat; a second motor that generates a driving force for folding the second vehicle seat; a first sensor that detects at least one of a rotational speed and a rotational amount of the first motor; a second sensor that detects at least one of a rotational speed and a rotational amount of the second motor; and at least one control module that controls at least one of the first motor and the second motor based on detection results of the first sensor and the second sensor, the control module controlling the at least one of the first motor and the second motor by controlling a duty ratio.)

1. A folding control device of a vehicle seat for controlling folding or unfolding of a first vehicle seat and a second vehicle seat, comprising:

a first motor that generates a driving force for folding the first vehicle seat;

a second motor that generates a driving force for folding the second vehicle seat;

a first sensor that detects at least one of a rotational speed and a rotational amount of the first motor;

a second sensor that detects at least one of a rotational speed and a rotational amount of the second motor; and

at least one control module that controls at least one of the first motor and the second motor based on detection results of the first sensor and the second sensor,

the control module controls at least one of the first motor and the second motor by controlling a duty cycle.

2. The folding control device of a vehicle seat according to claim 1,

the control module includes:

a first control unit that controls a first motor based on a detection result of the first sensor; and

and a second control unit that controls the second motor based on a detection result of the second sensor.

3. The folding control device of a vehicle seat according to claim 1,

when the control module receives a folding or unfolding command of the first vehicle seat and the second vehicle seat based on an operation of a user,

the control module applies driving signals with the same duty ratio to the first motor and the second motor.

4. The folding control device of a vehicle seat according to claim 3,

the control module compares a first pulse number output by the first sensor with a second pulse number output by the second sensor in a preset time period, and when the difference between the first pulse number and the second pulse number is more than a preset value a, the control module adjusts the duty ratio of a driving signal applied to a motor with a high pulse number downwards.

5. The folding control device of a vehicle seat according to claim 4,

the control module applies a driving signal of the same duty ratio to the first motor and the second motor when a difference between the first pulse number and the second pulse number is reduced to be less than a preset c by down-regulating the duty ratio,

and c is a value less than a.

6. The folding control device of a vehicle seat according to claim 3,

the control module compares a first pulse number output by the first sensor with a second pulse number output by the second sensor in a preset time period, and when the difference between the first pulse number and the second pulse number is more than a preset b, the control module stops applying a driving signal transmitted to a motor with a high pulse number.

7. The folding control device of a vehicle seat according to claim 6,

the control module stops applying the driving signal transmitted to the motor with high pulse number, and when the difference between the first pulse number and the second pulse number is reduced to be less than a preset value a, the control module down-regulates the duty ratio of the driving signal applied to the motor with high pulse number,

the a is a value less than the b.

8. A folding control method of a vehicle seat, which utilizes a folding control device for controlling folding or unfolding of a first vehicle seat and a second vehicle seat,

the folding control device includes: a first motor that generates a driving force for folding the first vehicle seat; a second motor that generates a driving force for folding the second vehicle seat; a first hall sensor that detects at least one of a rotational speed and a rotational amount of the first motor; a second hall sensor detecting at least one of a rotational speed and a rotational amount of the second motor; and at least one control module that controls at least one of the first motor and the second motor based on detection results of the first hall sensor and the second hall sensor,

the folding control method of the vehicle seat includes the steps of:

receiving a fold or unfold command for the first vehicle seat and the second vehicle seat from a user;

the control module applies driving signals with the same duty ratio to the first motor and the second motor;

the first Hall sensor and the second Hall sensor respectively acquire the position information of the first motor and the second motor so as to acquire a first pulse and a second pulse;

the control module compares the first pulse number with the second pulse number in a preset time period; and

the control module controls at least one of the first motor and the second motor based on a difference between the first number of pulses and the second number of pulses.

9. The folding control method of a vehicle seat according to claim 8,

the step of comparing the first number of pulses and the second number of pulses comprises:

a first comparison step of comparing whether the difference between the first pulse number and the second pulse number is a preset value a or more; and

a second comparison step of comparing whether or not the difference between the first pulse number and the second pulse number is a predetermined value b or more,

the b is a value greater than the a.

10. The folding control method of a vehicle seat according to claim 9,

the step of the control module controlling at least one of the first motor and the second motor based on the difference between the first pulse number and the second pulse number when the difference between the first pulse number and the second pulse number is a or more in the first comparing step and the difference between the first pulse number and the second pulse number is less than b in the second comparing step includes:

a step in which the control module down-regulates a duty ratio of a drive signal applied to a motor having a high number of pulses out of the first pulse and the second pulse;

comparing for the third time, wherein the control module compares whether the difference between the first pulse number and the second pulse number in a preset time period is more than or equal to preset c; and

and when the difference between the first pulse number and the second pulse number is smaller than a preset value c, the control module restores the duty ratio of the drive signal with the duty ratio adjusted downwards to the original state.

11. The folding control method of a vehicle seat according to claim 9,

the step of the control module controlling at least one of the first motor and the second motor based on the difference between the first pulse number and the second pulse number when the difference between the first pulse number and the second pulse number is a or more in the first comparing step and the difference between the first pulse number and the second pulse number is b or more in the second comparing step includes:

the control module stops applying a driving signal to a motor with a high pulse number in the first pulse and the second pulse;

the control module compares whether the difference between the first pulse number and the second pulse number in a preset time period is more than b; and

and a step in which the control module re-applies the driving signal to the motor that has stopped applying the driving signal when the difference between the first pulse number and the second pulse number is greater than or equal to b.

Technical Field

The present invention relates to a folding control apparatus and a control method of a vehicle seat, and more particularly, to a folding control apparatus and a control method of a vehicle seat in which two vehicle seats can perform folding or unfolding at the same speed when a user requests the folding or unfolding of the two vehicle seats.

Background

In general, a driver can sit on a vehicle seat in a comfortable posture so as not to feel fatigue even when traveling over a long distance, the vehicle seat including: a seat cushion which is slidably disposed on an indoor floor in a front-rear direction; and a seat back rotatably disposed at a predetermined angle with respect to the seat cushion.

Such a seat has various convenient functions for providing comfort to a passenger, in which the folding function is to provide convenience to a driver by adjusting the inclination of the seat back.

Wherein, in the seat having the folding function, the seat back is coupled to the seat cushion frame, the seat back is coupled to the recliner arm, and the recliner arm is rotatably coupled to the seat cushion frame through the recliner and the folding device, so that the seat back is folded forward according to the operation of the folding device.

On the other hand, the folding device is provided with a motor to perform the folding function of each seat, but even if the same motor is installed in the folding device of each seat and the same driving signal is applied, a difference in operation speed occurs due to the distribution of the motor and gears, etc. and a voltage drop caused by the wiring structure of the system.

Therefore, even if the user inputs the fold switches of the two vehicle seats, a speed difference occurs when each seat is folded, and thus, a problem in terms of sensitivity may be caused.

On the other hand, the following prior art documents disclose a seat back folding device capable of generating an elastic force in a direction in which a seat back is folded at an initial stage of folding the seat back using one return spring and starting to apply the elastic force in a direction opposite to the seat back folding after rotating a predetermined angle, so that an impact can be buffered when folding the seat back without an additional component, thereby saving a manufacturing cost of a product. However, the following prior art documents only disclose the above-described contents regarding the seat back folding device, and do not disclose the technical gist of the present invention.

Documents of the prior art

Patent document

(patent document 0001) Korean patent laid-open publication No. 10-1586947

Disclosure of Invention

Technical problem to be solved

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a folding control device and a control method for a vehicle seat, which can control the final folding time to be the same when two or more seats are folded, regardless of the voltage drop due to the seats or the vehicle body, or the manufacturing distribution of motors, gears, and the like.

The object of the present invention is not limited to the above-mentioned object, and other objects of the present invention which are not mentioned can be understood by the following description, and other objects of the present invention which are not mentioned can be more clearly understood by the embodiments of the present invention. The object of the present invention can be achieved by the embodiments and combinations thereof described in the claims.

(II) technical scheme

The folding control device and the control method for a vehicle seat for solving the above object of the present invention include the following configurations.

A folding control device of a vehicle seat according to an embodiment of the present invention is for controlling folding or unfolding of a first vehicle seat and a second vehicle seat, and includes: a first motor that generates a driving force for folding the first vehicle seat; a second motor that generates a driving force for folding the second vehicle seat; a first sensor that detects at least one of a rotational speed and a rotational amount of the first motor; a second sensor that detects at least one of a rotational speed and a rotational amount of the second motor; and at least one control module that controls at least one of the first motor and the second motor based on detection results of the first sensor and the second sensor, the control module controlling the at least one of the first motor and the second motor by controlling a duty ratio.

According to one embodiment, the control module comprises: a first control unit that controls a first motor based on a detection result of the first sensor; and a second control unit that controls the second motor based on a detection result of the second sensor.

According to one embodiment, when the control module receives a folding or unfolding command of the first and second vehicle seats based on a user's operation, the control module applies driving signals of the same duty ratio to the first and second motors.

According to one embodiment, the control module compares a first pulse number output by the first sensor with a second pulse number output by the second sensor in a preset time period, and when the difference between the first pulse number and the second pulse number is greater than or equal to a preset value a, the control module adjusts the duty ratio of the driving signal applied to the motor with the high pulse number downwards.

According to one embodiment, when the difference between the first pulse number and the second pulse number is reduced to less than a preset c by down-regulating the duty ratio, the control module applies the driving signals of the same duty ratio to the first motor and the second motor.

According to one embodiment, the control module compares a first number of pulses output from the first sensor with a second number of pulses output from the second sensor for a preset period of time, and when a difference between the first number of pulses and the second number of pulses is b or more, which is preset, the control module stops applying the driving signal transmitted to the motor having a high number of pulses.

According to one embodiment, the control module suspends application of the driving signal transmitted to the motor with the high pulse number, and when the difference between the first pulse number and the second pulse number decreases to be less than a preset value a, the control module down-regulates the duty ratio of the driving signal applied to the motor with the high pulse number, wherein the value a is less than the value b.

A fold control method of a vehicle seat according to an embodiment of the invention, which utilizes a fold control device for controlling folding or unfolding of a first vehicle seat and a second vehicle seat, the fold control device including: a first motor that generates a driving force for folding the first vehicle seat; a second motor that generates a driving force for folding the second vehicle seat; a first hall sensor that detects at least one of a rotational speed and a rotational amount of the first motor; a second hall sensor detecting at least one of a rotational speed and a rotational amount of the second motor; and at least one control module for controlling at least one of the first motor and the second motor based on the detection results of the first hall sensor and the second hall sensor, wherein the folding control method of the vehicle seat comprises the following steps: receiving a fold or unfold command for the first vehicle seat and the second vehicle seat from a user; the control module applies driving signals with the same duty ratio to the first motor and the second motor; the first Hall sensor and the second Hall sensor respectively acquire the position information of the first motor and the second motor so as to acquire a first pulse and a second pulse; the control module compares the first pulse number with the second pulse number in a preset time period; and the control module controls at least one of the first motor and the second motor based on a difference between the first number of pulses and the second number of pulses.

The step of comparing the first number of pulses and the second number of pulses comprises: a first comparison step of comparing whether the difference between the first pulse number and the second pulse number is a preset value a or more; and a second comparison step of comparing whether the difference between the first pulse number and the second pulse number is greater than or equal to a preset value b, wherein b is a value greater than a.

The step of the control module controlling at least one of the first motor and the second motor based on the difference between the first pulse number and the second pulse number when the difference between the first pulse number and the second pulse number is a or more in the first comparing step and the difference between the first pulse number and the second pulse number is less than b in the second comparing step includes: a step in which the control module down-regulates a duty ratio of a drive signal applied to a motor having a high number of pulses out of the first pulse and the second pulse; comparing for the third time, wherein the control module compares whether the difference between the first pulse number and the second pulse number in a preset time period is more than or equal to preset c; and when the difference between the first pulse number and the second pulse number is smaller than a preset value c, the control module restores the duty ratio of the drive signal with the duty ratio adjusted downwards to the original state.

The step of the control module controlling at least one of the first motor and the second motor based on the difference between the first pulse number and the second pulse number when the difference between the first pulse number and the second pulse number is a or more in the first comparing step and the difference between the first pulse number and the second pulse number is b or more in the second comparing step includes: the control module stops applying a driving signal to a motor with a high pulse number in the first pulse and the second pulse; the control module compares whether the difference between the first pulse number and the second pulse number in a preset time period is more than b; and a step in which the control module re-applies the drive signal to the motor that has stopped applying the drive signal when the difference between the first pulse number and the second pulse number is greater than or equal to b.

(III) advantageous effects

The present invention can obtain the following effects by the above-described embodiments, the configurations and combinations and the use relationships described below.

According to the folding control device and the control method of the vehicle seat of one embodiment of the present invention, it is possible to perform control to detect the rotation states of the two motors respectively provided in the two vehicle seats in real time, and when the rotation states of the two motors are different, adjust the driving signals transmitted to the motors in real time to make the final folding times of the two vehicle seats the same, thereby improving the quality in terms of the feeling, and thus, it is possible to improve the customer satisfaction.

Drawings

Fig. 1 is a schematic diagram for explaining a problem of a conventional folding control device of a vehicle seat.

Fig. 2 and 3 are block diagrams schematically showing various configuration examples of a folding control device of a vehicle seat according to an embodiment of the present invention.

Fig. 4 is a diagram for explaining various embodiments of a folding section in the folding control device of the vehicle seat according to one embodiment of the invention.

Fig. 5 is a flowchart showing a folding control method of a vehicle seat according to an embodiment of the invention in time series.

Description of the reference numerals

100: first vehicle seat 200: second vehicle seat

110: first motor 210: second electric machine

310. 320, and (3) respectively: control module

Detailed Description

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the following embodiments. This example is provided to more fully illustrate the present invention to those skilled in the art.

In addition, terms such as "… part", "unit", "module", and the like described in the specification denote units that process at least one function or operation, and may be implemented by hardware or software, or a combination of hardware and software.

In the present specification, the first, second, and the like, which are names of components, are used for distinguishing the components having the same name, and the description below is not limited to this order.

Next, a folding control of a conventional vehicle seat will be described with reference to fig. 1.

In the case of the folding control of the conventional vehicle seat, as shown in fig. 1, seats in the same position are operated by the switch at the same timeAnd a seatWhen a folding request is input, the seatAnd a seatFolding is performed.

However, the folding speed between the two seats is different due to voltage drop caused by the seats or the vehicle body and tolerance of the motor and the gear, and as a result, even if the folding switches of the two seats are operated at the same time, the time when the two seats finally complete folding is different.

The present invention has been made to solve the above problems, and the present invention can control to operate the seat through the switch at the same timeAnd a seatWhen a folding request is input, the folding speeds of the two seats are made the same, so that the final folding time can be made the same. Next, a folding control device of a vehicle seat according to an embodiment of the invention is explained with reference to fig. 2 to 4.

The folding control device of a vehicle seat according to one embodiment of the present invention is a folding control device of a vehicle seat for controlling folding or unfolding of first and second vehicle seats 100 and 200, which includes a first motor 110, a second motor 210, a first sensor, a second sensor, and control modules 310 and 320.

The first motor 110 performs a function of generating a driving force for folding the first vehicle seat 100, and the second motor 210 performs a function of generating a driving force for folding the second vehicle seat 200.

The first sensor performs a function of detecting a rotational speed, a rotational amount, etc. of the first motor 110, and the second sensor performs a function of detecting a rotational speed, a rotational amount, etc. of the second motor 210, and the first sensor and the second sensor are preferably hall sensors.

The control module 310, 320 controls at least one of the first motor 110 and the second motor 210 based on the detection results of the first sensor and the second sensor, and such control module 310, 320 controls the driving speed of the first motor 110 and the second motor 210 by controlling the duty ratio of the driving signal applied to at least one of the first motor 110 and the second motor 210.

On the other hand, as shown in fig. 2, the control modules 310 and 320 may include only one control unit and individually control the first motor 110 and the second motor 210 using one control unit.

That is, one control unit may calculate the respective pulse numbers received from the first and second sensors to determine the positions of the first and second motors 110 and 210, thereby applying the driving signals to the first and second motors 110 and 210.

In addition, as shown in fig. 3, the control modules 310 and 320 may include a first control unit 310 and a second control unit 320 that control the first motor 110 and the second motor 210, respectively, and in this case, the first control unit 310 and the second control unit 320 need to confirm the detection values of the sensors provided in the other-side seat, and thus the first control unit 310 and the second control unit 320 need to communicate with each other.

On the other hand, when the control modules 310, 320 receive the folding or unfolding commands of the first and second vehicle seats 100, 200 based on the user's operation, the control modules 310, 320 apply driving signals to the first and second motors 110, 210 and apply driving signals having the same duty ratio to both motors.

Then, the first and second sensors continue to monitor the position information of the first and second motors 110 and 210 and compare the first number of pulses output from the first sensor and the second number of pulses output from the second sensor for a preset period of time.

Then, when it is determined that the difference between the first pulse number and the second pulse number is greater than or equal to a preset value a, the control modules 310 and 320 lower the duty ratio of the driving signal applied to the motor having the high pulse number.

For example, in the case where the control module 310, 320 applies a drive signal of 100% duty ratio to the first motor 110 and the second motor 210 for the first time, when the drive speed of the first motor 110 becomes faster than the drive speed of the second motor 210 and the first vehicle seat 100 is folded in preference to the second vehicle seat 200, the control module 310, 320 applies a drive signal of less than 100% duty ratio (e.g., 90%, 80%, 70%, etc.) to the first motor 110, which is rotating faster.

In this case, the rotational speed of the first motor 110 is reduced, and thus the folded position of the second vehicle seat 200 can be close to the folded position of the first vehicle seat 100.

On the other hand, after the control modules 310 and 320 down-regulate the duty ratio of the driving signal applied to the first motor 110, the first and second sensors continue to monitor the rotation states of the first and second motors 110 and 120, and in the case where the rotation speed of the first motor 110 is reduced, the control modules 310 and 320 restore the duty ratio of the driving signal applied to the first motor 100, which has been down-regulated, to a 100% duty ratio when the folding angles of the first and second vehicle seats 100 and 200 are close.

For example, the control module 310, 320 suspends application of the driving signal transmitted to the motor having the high number of pulses, and may apply the driving signal of the same duty ratio to the first motor 110 and the second motor 120 when the difference between the first number of pulses and the second number of pulses decreases to be less than a preset c. c may be a value less than a. For example, c may be 3 pulse numbers.

On the other hand, when the a is an excessively large value, the gap between the first vehicle seat 100 and the second vehicle seat 200 changes, and when the a is an excessively small value, the duty ratio of the driving signal applied to the motor changes too frequently, and therefore, the operation of the vehicle seat may be unnatural, and thus it is preferable to appropriately set the a.

Although the control of the vehicle seat when the vehicle seat is folded has been described above, the control may be performed by the same method when the vehicle seat is unfolded.

Further, when the duty ratio applied to the motor is excessively reduced, a motor stop or electromagnetic compatibility (EMC) noise problem may occur, and therefore, it is preferable that the above-described duty ratio control is performed only in a specific section when the vehicle seat is folded.

For example, when the vehicle seat is folded, the duty control is performed only in the PC to PD interval shown in fig. 4, and when the vehicle seat is unfolded, the duty control is performed only in the PA to PB interval, whereby the above-described problem can be solved.

On the other hand, since the interval between the two vehicle seats is very large, it is difficult to narrow the interval between the two vehicle seats by controlling the motor speed only by changing the duty ratio.

That is, when the control modules 310 and 320 compare the first number of pulses output from the first sensor and the second number of pulses output from the second sensor within a preset time period and as a result, the difference between the first number of pulses and the second number of pulses is greater than or equal to b, which is a value greater than a, and cannot be overcome by controlling only the duty ratio, the control modules 310 and 320 stop applying the driving signal transmitted to the motor having the high number of pulses.

That is, it is preferable that the folding of the vehicle seat folded first is stopped, and then when the difference between the two pulse numbers is reduced to be smaller than b, the interval between the two vehicle seats is reduced by the duty control described above.

For example, the control module 310, 320 suspends application of the driving signal transmitted to the motor having the high pulse number, so that the control module 310, 320 may down-regulate the duty ratio of the driving signal applied to the motor having the high pulse number when the difference between the first pulse number and the second pulse number decreases to be less than a preset a. In addition, when the difference between the first pulse number and the second pulse number is decreased to be less than the preset c by the down-regulation of the duty ratio, the control modules 310 and 320 may apply the driving signals of the same duty ratio to the first motor 110 and the second motor 120.

Next, a folding control method of a vehicle seat according to an embodiment of the present invention will be described with reference to fig. 5, in which detailed description of the same contents as those of the above-described folding control apparatus of a vehicle seat according to an embodiment of the present invention will be omitted.

A folding control method of a vehicle seat according to one embodiment of the present invention relates to a folding control method of a vehicle seat using a folding control device for controlling folding or unfolding of a first vehicle seat 100 and a second vehicle seat 200, and as shown in fig. 5, first, a step of receiving a folding or unfolding command for the first vehicle seat 100 and the second vehicle seat 200 from a user is performed (S100).

Then, the steps of the control modules 310 and 320 applying the driving signals with the same duty ratio to the first motor 110 and the second motor 210 (S200) and the steps of the first hall sensor and the second hall sensor acquiring the position information of the first motor 110 and the second motor 210 respectively to acquire the first pulse and the second pulse (S300) are sequentially performed.

Then, the step of comparing the first pulse number and the second pulse number in a preset time period by the control module 310, 320 is performed, and this step of comparing the first pulse number and the second pulse number may be subdivided into a first comparison step (S400) of comparing whether a difference between the first pulse number and the second pulse number is a preset a or more and a second comparison step (S500) of comparing whether a difference between the first pulse number and the second pulse number is a preset b or more, where b is a value greater than a.

The step of the control module 310, 320 controlling at least one of the first motor 110 and the second motor 210 is performed according to the comparison result of the first comparison step (S400) and the second comparison step (S500) which are sequentially performed.

That is, when the difference between the first pulse number and the second pulse number is a or more in the first comparison step (S400) and the difference between the first pulse number and the second pulse number is less than b in the second comparison step (S500), the interval between the two vehicle seats may be reduced only by changing the duty ratio of the driving signal applied to the motor.

In this case, therefore, the step (S640) of the control module 310, 320 down-regulating the duty ratio of the drive signal applied to the motor having the higher number of pulses out of the first and second pulses is performed.

Then, the first and second hall sensors continue to detect the position information of the first and second motors 110 and 210 while continuing to compare the first and second pulse numbers.

That is, the third comparison step (S650) is performed in which the control modules 310 and 320 compare whether or not the difference between the first pulse number and the second pulse number in a preset time period is a preset c or more, where c is preferably set to b or less.

Then, when the difference between the first pulse number and the second pulse number is smaller than the preset value c, the step of the control module 310, 320 restoring the duty ratio of the down-regulated driving signal to the original state is executed (S660).

On the other hand, when the difference between the first pulse number and the second pulse number is a or more in the first comparison step (S400) and the difference between the first pulse number and the second pulse number is b or more in the second comparison step (S500), the interval between the two vehicle seats cannot be reduced by only changing the drive signal applied to the motor.

In this case, therefore, the control module 310, 320 performs the step of stopping the application of the drive signal to the motor having the higher number of pulses of the first pulse and the second pulse (S610).

Then, the first and second hall sensors continue to detect the position information of the first and second motors 110 and 210 while continuing to compare the first and second pulse numbers.

That is, the control module 310, 320 performs the step of comparing again whether the difference between the first pulse number and the second pulse number in the preset time period is b or more (S620), and at this time, when the difference between the first pulse number and the second pulse number is b or more, the control module 310, 320 performs the step of applying the driving signal again to the motor in which the application of the driving signal has been stopped (S630), and then the control module 310, 320 performs the step of down-adjusting the duty ratio of the driving signal applied to the motor having the higher pulse among the first pulse number and the second pulse number (S640).

The foregoing detailed description is illustrative of the invention. While the foregoing is directed to preferred embodiments of the present invention, the present invention may be used in many different combinations, permutations and environments. That is, variations and modifications may be made within the scope of the inventive concept disclosed in the present specification, within the scope equivalent to the disclosed content, and/or within the skill or knowledge of the art. The described embodiments explain the best mode for realizing the technical idea of the present invention, and may be variously modified in accordance with the requirements in the specific application field and use of the present invention. Therefore, the above detailed description of the invention does not limit the invention to the disclosed embodiments. In addition, it is to be construed that the claims include other embodiments.