Patent Publication Number: US-2023147161-A1

Title: Apparatus and Method of Controlling Door for Vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 16/824,921, filed Mar. 20, 2020, which claims priority to Korean Patent Application No. 10-2019-0128352, filed on Oct. 16, 2019, which applications are hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an apparatus and a method of controlling a door for a vehicle. 
     BACKGROUND 
     A tailgate of a vehicle refers to a rear gate of a sports utility vehicle (SUV), a pickup truck or the like, and has been recently mounted with a system of warning a user that the tailgate may be safely opened together with a function of opening and closing the tailgate in an electric manner. 
     However, a safety opening warning system of the tailgate generally interworks with a rear parking sensor to sense only an obstacle in a horizontal direction adjacent to a bumper, such that it is difficult to sense an obstacle in a vertical direction in which the tailgate is opened, and the safety opening warning system and a tailgate switch are independently installed, which is disadvantageous in terms of cost and weight. 
     Meanwhile, in a case of a vehicle in which a rear license plate of the vehicle is positioned in the tailgate, the tailgate switch is installed in a concavely recessed portion on the license plate. 
     However, in a case of a vehicle in which a rear license plate is positioned in a rear bumper, a space in which the tailgate switch is installed in a hidden state may not be separately provided on a rear panel, such that it is difficult to configure the tailgate switch. 
     The tailgate switch may be installed in a state where it is directly exposed to an outer surface of the vehicle, but in this case, the tailgate switch may be easily contaminated, such that user&#39;s will to operate the tailgate switch is reduced. 
     The contents described as the related art have been provided only to assist in understanding the background of the present disclosure and should not be considered as corresponding to the related art known to those having ordinary skill in the art. 
     SUMMARY 
     Embodiments of the present disclosure provide an apparatus and a method of controlling a door for a vehicle capable of opening the door and sensing an obstacle using a sensor capable of sensing an object. 
     According to an embodiment of the present disclosure, an apparatus of controlling a door for a vehicle includes a sensor unit provided in a door for sensing an object adjacent to the outside of the door. A controller calculates a distance at which the object is positioned on the basis of a signal sensed by the sensor unit and controls the door to be opened in a case where the distance to the object is gradually reduced in a state where the door is closed, such that the object is sensed within a predetermined range. 
     The door may be a tailgate of the vehicle and the sensor unit may be installed at an emblem mounted on the tailgate. 
     The sensor unit may be an ultrasonic sensor. The ultrasonic sensor may be installed on a rear surface of the emblem, and ultrasonic waves may be transmitted and received through a logo portion of the center of the emblem. 
     The controller may include a transmitter transmitting a voltage signal to the ultrasonic sensor, a receiver receiving a voltage signal from the ultrasonic sensor, a calculator calculating the distance to the object depending on a magnitude of the voltage signal received at the receiver, a determiner determining whether or not an operation condition of a tailgate is satisfied on the basis of an opened and closed state of the tailgate and a change in the distance to the object, and a driving controller applying an operation command to control an operation of the tailgate according to the operation condition of the tailgate when the operation condition of the tailgate is satisfied. 
     The controller may divide and set sensing ranges for each sensing distance of the sensor unit, and control the door to be opened while being unlatched in a case where the object is sequentially sensed from a sensing range distant from the sensor unit to a sensing range close to the sensor unit. 
     The controller may control the door so that the opening of the door is stopped in a case where the object enters a maximum sensing distance of the sensor unit and is sensed within the maximum sensing distance in a process in which the door is opened. 
     The controller may control the door so that the opening of the door is continued in a case where the object is not sensed in the maximum sensing range most distant from the sensor unit and is preferentially sensed in the other sensing ranges in the process in which the door is opened. 
     The controller may set the maximum sensing distance in a state where the door is opened to be longer than that in a state where the door is closed. 
     The maximum sensing distance of the sensor unit may be changed depending on the number of times of voltage application from the controller, and the controller may increase the number of times of voltage application to the sensor unit in the state where the door is opened as compared with the number of times of voltage application to the sensor unit in the state where the door is closed, such that the maximum sensing distance of the sensor unit becomes long. 
     The controller may set the maximum sensing distance of the sensor unit to become long when an operation signal of a door operator operating the door is input together with an unlatching signal of a door latch in the state in which the door is closed. 
     The controller may set the maximum sensing distance of the sensor unit to become long when an unlatching signal of a door latch is input. 
     The controller may set the maximum sensing distance of the sensor unit to become long when an operation signal of a door operator operating the door is input. 
     According to another embodiment of the present disclosure, a method of controlling a door for a vehicle includes, a sensing step of sensing, by a sensor unit, an object adjacent to the outside of a door, a calculating step of calculating, by a controller, a distance at which the object is positioned on the basis of a signal sensed by the sensor unit, and an operation controlling step of controlling, by the controller, the door to be opened in a case where the distance to the object is gradually reduced in a state where the door is closed, such that the object is sensed within a predetermined range. 
     The method of controlling a door for a vehicle may further include, after the calculating step, a range setting step of dividing and setting sensing ranges for each sensing distance of the sensor unit, and wherein in the operation controlling step, in a case where the object is sequentially sensed from a sensing range distant from the sensor unit to a sensing range close to the sensor unit, the door is controlled to be opened. 
     After the operation controlling step, in a case where the object enters a maximum sensing distance of the sensor unit and is sensed within the maximum sensing distance in a process in which the door is opened, the door may be controlled so that the opening of the door is stopped. 
     After the operation controlling step, in a case where the object is not sensed in a maximum sensing range most distant from the sensor unit and is preferentially sensed in the other sensing ranges in a process in which the door is opened, the door may be controlled so that the opening of the door is continued. 
     In the range setting step, the maximum sensing distance in a state where the door is opened may be set to be longer than that in a state where the door is closed. 
     The maximum sensing distance of the sensor unit may be changed depending on the number of times of voltage application from the controller, and in the range setting step, the number of times of voltage application to the sensor unit in the state where the door is opened may be increased as compared with the number of times of voltage application to the sensor unit in the state where the door is closed, such that the maximum sensing distance of the sensor unit becomes long. 
     In the range setting step, when an operation signal of a door operator operating the door is input together with an unlatching signal of a door latch in the state in which the door is closed, the maximum sensing distance of the sensor unit may be changed to be long. 
     In the range setting step, when an unlatching signal of a door latch is input, the maximum sensing distance of the sensor unit may be changed to be long. 
     In the range setting step, when an operation signal of a door operator operating the door is input, the maximum sensing distance of the sensor unit may be changed to be long. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a tailgate and an emblem appearance that may be applied to the present disclosure. 
         FIG.  2    is a view illustrating a connection relationship between a sensor unit, an emblem, and a controller according to the present disclosure. 
         FIG.  3    is a view illustrating a maximum sensing distance and a sensing range of a sensor unit in a state where a tailgate according to the present disclosure is closed. 
         FIG.  4    is a view illustrating a maximum sensing distance and a sensing range of the sensor unit in a state where the tailgate according to the present disclosure is unlatched and opened. 
         FIG.  5    is a flowchart for describing processes of controlling an operation of the tailgate according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Hereinafter, a folding personal mobility vehicle according to embodiments of the present disclosure is described with reference to the accompanying drawings. 
     An embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. 
     An apparatus of controlling a door for a vehicle according to the present disclosure is configured to include a sensor unit  30  and a controller  100 . 
     The present disclosure will be described in detail with reference to  FIG.  1   . First, the sensor unit  30  is provided in a door  10 , and senses an object adjacent to the outside of the door  10 . 
     The controller  100  calculates a distance at which the object is positioned on the basis of a signal sensed by the sensor unit  30 , and controls the door  10  to be opened in a case where the distance to the object is gradually reduced in a state where the door  10  is closed, such that the object is sensed within a predetermined range. 
     Here, the door  10  may be a tailgate  10  of the vehicle. In addition, the sensor unit  30  may be installed at an emblem  20  mounted on the tailgate  10 . 
     For example, in a vehicle in which a rear license plate is installed in a rear bumper, the emblem  20  of the vehicle may be installed in the middle of the tailgate  10 , and the sensor unit  30  may be installed at the emblem  20 . 
     According to such a configuration, in a case where a user&#39;s hand is positioned close to the sensor unit  30  in a state where the tailgate  10  is closed, a distance between the sensor unit  30  and the hand that becomes close to the sensor unit  30  is calculated. 
     Therefore, when the distance between the sensor unit  30  and the hand is within a predetermined distance, the controller wo applies an unlatching command of a door latch  50  to unlatch the door latch  50 , such that the tailgate  10  is unlatched, and applies an operation command of a drive unit to extend the drive unit, such that the tailgate  10  is opened. For reference, the unlatching operation of the tailgate  10  as described above may be configured to be operated only in a case where a smart key is sensed in the vicinity of the sensor unit  30 . 
     As described above, in the present disclosure, the tailgate  10  is unlatched only by a motion of bringing the hand to the vicinity of the sensor unit  30 , such that the unlatching operation of the tailgate  10  is easily and conveniently performed and a more luxurious vehicle image is implemented. In addition, the tailgate  10  is unlatched in a non-contact manner without directly touching the sensor unit  30 , such that the unlatching operation of the tailgate  10  may be performed without repulsion even in a case where the tailgate  10  is contaminated. 
     In addition, the sensor unit  30  according to the present disclosure is an ultrasonic sensor, and the ultrasonic sensor  30  is installed on a rear surface of the emblem  20 . 
     In addition, ultrasonic waves are transmitted and received through a logo portion of the center of the emblem  20 . 
     For example, the ultrasonic sensor  30  is installed so that a rear surface of an ultrasonic reflection plate  40  is adhered to the center of the ultrasonic sensor  30  and a front surface of the ultrasonic reflection plate  40  faces the logo portion of the center of the emblem  20 . In addition, both sides of a rear surface of the emblem  20  may be fastened to an outer surface of a panel of the tailgate  10 . 
     Therefore, an electrical signal applied from the controller  100  is applied to the ultrasonic sensor  30  to be converted into vibrations, and the vibrations generated by the ultrasonic sensor  30  are converted into sound waves through the ultrasonic reflection plate  40 . 
     In addition, sound waves sensed outside the ultrasonic reflection plate  40  are converted into vibrations by the ultrasonic reflection plate  40  and are then transferred to the sensor unit  30 , and the vibrations input to the sensor unit  30  are received as an electronic signal by the controller  100 . 
     That is, in a case of the vehicle in which the rear license plate is installed in the rear bumper, it is not easy to configure a switch of the tailgate  10  on an outer surface of a panel of the tailgate  10  due to a design of the vehicle, but the present disclosure has an effect that the sensor unit  30  is concealed through the emblem  20  provided on the tailgate  10 , such that the switch of the tailgate  10  may be implemented without hindering a rear design of the vehicle. 
     In addition, the controller  100  is configured to include a transmitter  110  transmitting a voltage signal to the ultrasonic sensor  30 , a receiver  120  receiving a voltage signal from the ultrasonic sensor  30 , a calculator  130  calculating a distance to an object depending on a magnitude of the voltage signal input to the receiver  120 , a determiner (comparator)  140  determining whether or not an operation condition of the tailgate  10  is satisfied on the basis of an opened and closed state of the tailgate  10  and a change in the distance to the object, and a driving controller  150  applying an operation command to control an operation of the tailgate  10  according to the operation condition of the tailgate  10  when the operation condition of the tailgate  10  is satisfied. 
     For example, in a case where a voltage of 3 V is applied from the transmitter  100 , the distance to the object may be calculated to be 0 to 7 cm when a voltage received by the receiver  120  is 0 to 1 V, may be calculated to be 7 to 13 cm when a voltage received by the receiver  120  is 1 to 2 V, and may be calculated to be 13 to 20 cm when a voltage received by the receiver  120  is 2 to 3 V. 
     For reference, a distance range to the object may be divided on the basis of a maximum voltage that may be received by the receiver  120 , and the distance to the object may be calculated using the voltage received by the receiver  120 . 
     In addition, the operation condition of the tailgate  10  determined by the comparator  140  may be whether or not the distance to the object is gradually reduced in a state where the tailgate  10  is closed. 
     In addition, the operation condition of the tailgate  10  may be whether or not the object is sensed within a maximum sensing distance that may be sensed by the sensor unit  30  in a state where the tailgate  10  is unlatched. 
     Therefore, the driving controller  150  may open the tailgate  10  while unlatching the tailgate  10  in a case where the distance to the object is gradually reduced in the state where the tailgate  10  is closed. 
     In addition, the driving controller  150  may stop the opening of the tailgate  10  in a case where the object is sensed within the maximum sensing distance that may be sensed by the sensor unit  30  in a state where the tailgate  10  is unlatched. 
     For reference, the controller  100  according to an embodiment of the present disclosure may be implemented through a nonvolatile memory (not illustrated) configured to store an algorithm configured to control operations of various components of the vehicle or data on software instructions reproducing the algorithm and a processor (not illustrated) configured to perform operations described below using the data stored in the nonvolatile memory. Here, the memory and the processor may be implemented as individual chips. Alternatively, the memory and the processor may be integrated with each other and implemented as a single chip. The processor may have a form of one or more processors. 
     Hereinafter, a configuration of the controller wo will be described in more detail. The controller  100  may divide and set sensing ranges for each sensing distance of the sensor unit  30 , and control the door  10  to be opened while being unlatched in a case where the object is sequentially sensed from a sensing range distant from the sensor unit  30  to a sensing range close to the sensor unit  30 . 
     For example, the controller  100  may set a sensing range in which a distance to the object sensed by the ultrasonic sensor  30  is 0 to 7 cm to Step  1 , set a sensing range in which a distance to the object sensed by the ultrasonic sensor  30  is 7 to 13 cm to Step  2 , and set a sensing range in which a distance to the object sensed by the ultrasonic sensor  30  is 13 to 20 cm to Step  3 . 
     That is, the controller wo may open the tailgate  10  in a case where the object enters the sensing range of Step  2  from the sensing range of Step  3  and is sensed in the sensing range of Step  2 . 
     In addition, the controller  100  may open the tailgate  10  in a case where the object enters the sensing range of Step  1  from the sensing range of Step  2  and is sensed in the sensing range of Step  1 . 
     In addition, the controller  100  may control the door  10  so that the opening of the door  10  is stopped in a case where the object enters the maximum sensing distance of the sensor unit  30  and is sensed within the maximum sensing distance in a process in which the door  10  is opened. 
     For example, in a case where the object is sensed at the maximum sensing distance (an end portion of Step  3 ) that may be sensed by the ultrasonic sensor  30  in a process in which the tailgate  10  is opened, the controller  100  may stop the opening of the tailgate  10 . Therefore, in a case where an obstacle is present in a vertical direction of the tailgate  10  at the time of opening the tailgate  10 , the controller  100  may stop the opening of the tailgate  10  to prevent the tailgate  10  from colliding with the obstacle to be damaged. 
     In addition, the controller  100  may control the door  10  so that the opening of the door  10  is continued in a case where the object is not sensed in the maximum sensing range most distant from the sensor unit  30  and is preferentially sensed in the other sensing ranges in the process in which the door  10  is opened. 
     For example, when the object is not sensed at the maximum sensing distance (the end portion of Step  3 ) that may be sensed by the ultrasonic sensor  30  and is sensed in the sensing range of Step  1  or Step  2  in the process in which the tailgate  10  is opened, the controller  100  does not recognize the object as the obstacle to control the tailgate  10  so that the opening of the tailgate  10  may be continued. 
     In addition, the controller  100  may set a maximum sensing distance in a state where the door  10  is opened to be longer than that in a state where the door  10  is closed. 
     For example, in a case where the maximum sensing distance in a state where the tailgate  10  is closed is set to 20 cm, the controller  100  may set a maximum sensing distance in a state where the tailgate  10  is unlatched and opened to be 70 cm. 
     Therefore, sensing ranges divided within the maximum sensing distances are also different from each other. In detail, in the state where the tailgate  10  is closed, a sensing range of 0 to 7 cm may be set to Step  1 , a sensing range of 7 to 13 cm may be set to Step  2 , and a sensing range of 13 to 20 cm may be set to Step  3 , but in the state where the tailgate  10  is unlatched, a sensing range of 0 to 20 cm may be set to Step  1 , a sensing range of 20 to 50 cm may be set to 
     Step  2 , and a sensing range of 50 to 70 cm may be set to Step  3 . 
     In the present disclosure, the maximum sensing distance to the object may be changed depending on the number of times of voltage application. 
     In detail, the maximum sensing distance of the sensor unit  30  is changed depending on the number of times of voltage application from the controller  100 . 
     In addition, the controller  100  increases the number of times of voltage application to the sensor unit  30  in the state where the door  10  is opened as compared with the number of times of voltage application to the sensor unit  30  in the state where the door  10  is closed, such that the maximum sensing distance of the sensor unit  30  becomes long. 
     For example, in the state where the tailgate  10  is closed, the controller  100  applies a voltage of  3  V to the ultrasonic sensor  30  three times for one second, while in the state where the tailgate  10  is unlatched and opened, the controller  100  applies a voltage of  3  V to the ultrasonic sensor  30  nine times for one second. 
     That is, intensity of vibrations is changed depending on a difference in the number of times of voltage application to a diaphragm of the ultrasonic sensor  30  during the same time. The more the number of times of voltage application, the greater the vibrations, and the greater the vibrations, the greater the maximum sensing distance sensed by the ultrasonic sensor  30 . 
     Therefore, the number of times of voltage application is increased in the state where the tailgate  10  is unlatched as compared with the state where the tailgate  10  is closed, such that the maximum sensing distance to the object may be increased. Accordingly, in the state where the tailgate  10  is closed, a user may open the tailgate  10  without making a large motion, while in a process in which the tailgate  10  is opened, it is possible to more certainly prevent a damage risk of the tailgate  10  in preparation for an obstacle present in an opening path of the tailgate  10 . 
     In addition, the controller  100  may set the maximum sensing distance of the sensor unit  30  to become long when an operation signal of a door operator  60  operating the door  10  is input together with an unlatching signal of the door latch  50  in the state in which the door  10  is closed. 
     Here, the door latch  50  may be a latch  50  latching and unlatching the tailgate  10 , and the door operator  60  may be a spindle drive  60  opening and closing the tailgate  10 . 
     That is, the ultrasonic sensor  30  and the controller  100  transmit and receive signals through controller area network (CAN) communication. When the unlatching signal of the latch  50  and the operation signal of the spindle drive  60  are input to the controller  100 , these signals are used as triggers, such that the maximum sensing distance of the ultrasonic sensor  30  is set to become long. 
     In addition, as another example, when the unlatching signal of the door latch  50  is input, the maximum sensing distance of the sensor unit  30  may be changed to be long, and when an operation signal of a door operator  60  operating the door  10  is input, the maximum sensing distance of the sensor unit  30  may be changed to be long. 
     Meanwhile, a method of controlling a door according to the present disclosure is configured to include a sensing step of sensing, by the sensor unit  30 , an object adjacent to the outside of the door  10 ; a calculating step of calculating, by the controller  100 , a distance at which the object is positioned on the basis of on a signal sensed by the sensor unit  30 ; and an operation controlling step of controlling, by the controller  100 , the door  10  to be opened in a case where the distance to the object is gradually reduced in a state where the door  10  is closed, such that the object is sensed within a predetermined range. 
     In addition, the method of controlling a door according to the present disclosure further includes, after the calculating step, a range setting step of dividing and setting sensing ranges for each sensing distance of the sensor unit  30 . In the operation controlling step, in a case where the object is sequentially sensed from a sensing range distant from the sensor unit  30  to a sensing range close to the sensor unit  30 , the door  10  is controlled to be opened. 
     In addition, after the operation controlling step, in a case where the object enters the maximum sensing distance of the sensor unit  30  and is sensed within the maximum sensing distance in a process in which the door  10  is opened, the door  10  is controlled so that the opening of the door  10  is stopped. 
     However, after the operation controlling step, in a case where the object is not sensed in the maximum sensing range most distant from the sensor  30  and is preferentially sensed in the other sensing ranges in the process in which the door  10  is opened, the door  10  is controlled so that the opening of the door  10  is continued. 
     In addition, in the range setting step, a maximum sensing distance in a state where the door  10  is opened may be set to be longer than that in a state where the door  10  is closed. 
     Therefore, the maximum sensing distance of the sensor unit  30  is changed depending on the number of times of voltage application from the controller  100 . 
     In addition, in the range setting step, the number of times of voltage application to the sensor unit  30  in the state where the door  10  is opened is increased as compared with the number of times of voltage application to the sensor unit  30  in the state where the door  10  is closed, such that the maximum sensing distance of the sensor unit  30  becomes long. 
     In addition, in the range setting step, when an operation signal of a door operator  60  operating the door  10  is input together with an unlatching signal of the door latch  50  in the state in which the door  10  is closed, the maximum sensing distance of the sensor unit  30  may be changed to be long. 
     As another example, in the range setting step, when the unlatching signal of the door latch  50  is input, the maximum sensing distance of the sensor unit  30  may be changed to be long, and when the operation signal of the door operator  60  operating the door  10  is input, the maximum sensing distance of the sensor unit  30  may be changed to be long. 
     Processes of controlling the tailgate  10  according to the present disclosure will be sequentially described with reference to  FIG.  5   . In a case where the tailgate  10  is closed (S 10 ), it is determined whether or not the object is sensed through the ultrasonic sensor  30  (S 20 ). 
     In a case where the object is sensed in S 20 , a distance to the object is calculated (S 30 ) 
     Then, it is determined whether or not the distance to the object is gradually reduced (S 40 ), it is determined whether or not the object is sensed within a predetermined range (S 50 ) in a case where the distance to the object is gradually reduced, and the tailgate  10  is controlled to be opened while being unlatched (S 60 ) in a case where these conditions are satisfied. 
     Then, it is determined whether or not the object is sensed through the ultrasonic sensor  30  in a process in which the tailgate  10  is opened (S 70 ). 
     In a case where the object is sensed in S 70 , a distance to the object is calculated (S 80 ). 
     Then, it is determined whether or not the object is sensed within the maximum sensing range (S 90 ), and in a case where the object is sensed within the maximum sensing range, the opening of the tailgate  10  is stopped (S 100 ). 
     However, in a case where the object is not sensed in S 70  or in a case where the object is sensed within a range that is not the maximum sensing range in S 90 , the opening of the tailgate  10  is continued (S 110 ). 
     Meanwhile, a method of implementing an unlatching function of the tailgate  10  according to the present disclosure will be described. A user brings his/her hand closer to the ultrasonic sensor  30  in a state where he/she holds a smart key and stands in front of the tailgate  10 . 
     Therefore, in a case where a signal of Step  2  and a signal of Step  1  are sequentially input while the user&#39;s hand becomes gradually close to the ultrasonic sensor  30 , the controller  100  determines that an unlatching operation condition is satisfied, such that control is performed so that the tailgate  10  and the latch  50  are unlatched and the spindle drive  60  is extended. 
     Also in a case where a signal of Step  3  and a signal of Step  2  are sequentially input while the user&#39;s hand becomes close to the ultrasonic sensor  30 , the controller  100  may determine that the unlatching operation condition is satisfied. 
     Next, a method of implementing a function of sensing a rear obstacle after unlatching the tailgate  10  according to the present disclosure will be described by way of example. When a user holding a smart key opens the tailgate  10  in front of the tailgate  10 , the latch  50  is unlatched and the spindle drive  60  is operated, such that the tailgate  10  starts to be opened. 
     Therefore, in a case where a signal of Step  3 , which is the maximum sensing range, is input to the ultrasonic sensor  30  in a process in which the tailgate  10  is opened, it is determined that an operation stop condition in where collision is expected is satisfied, such that control is performed so that an operation of the spindle drive  60  is stopped, and an operation of the tailgate  10  is thus stopped. 
     However, in a case where a signal sensed by the ultrasonic sensor  30  in the process in which the tailgate  10  is opened is a signal of Step  2  or a signal of Step  1 , it is determined that an operation stop condition in where collision is expected is not satisfied, such that the operation of the tailgate  10  may be continued. 
     Next, another method of implementing a function of sensing a rear obstacle after unlatching the tailgate  10  according to the present disclosure will be described by way of example. When a user opens the tailgate  10  through an operation of a tailgate opening switch provided in the vehicle interior, the latch  50  is unlatched and the spindle drive  60  is operated, such that the tailgate  10  starts to be opened. 
     Therefore, in a case where a signal of Step  3 , which is the maximum sensing range, is input to the ultrasonic sensor  30  in a process in which the tailgate  10  is opened, it is determined that an operation stop condition in where collision is expected is satisfied, such that control is performed so that an operation of the spindle drive  60  is stopped, and an operation of the tailgate  10  is thus stopped. 
     However, in a case where a signal sensed by the ultrasonic sensor  30  in the process in which the tailgate  10  is opened is a signal of Step  2  or a signal of Step  1 , it is determined that an operation stop condition in where collision is expected is not satisfied, such that the operation of the tailgate  10  may be continued. 
     As described above, in the present disclosure, the tailgate  10  is unlatched only by a motion of bringing the hand to the vicinity of the sensor unit  30 , such that the unlatching operation of the tailgate  10  is easily and conveniently performed and a more luxurious vehicle image is implemented. In addition, the tailgate  10  is unlatched in a non-contact manner without directly touching the sensor unit  30 , such that the unlatching operation of the tailgate  10  may be performed without repulsion even in a case where the tailgate  10  is contaminated. 
     In addition, the sensor unit  30  performs a function of a tailgate switch in the state where the tailgate  10  is closed and performs a function of a rear sensor sensing a rear obstacle in the process in which the tailgate  10  is opened. Therefore, the tailgate switch and the rear sensor are integrated with each other, such that a cost and a weight may be reduced. 
     As set forth above, according to the present disclosure, the tailgate is unlatched only by a motion of bringing the hand to the vicinity of the sensor unit, such that the unlatching operation of the tailgate is easily and conveniently performed and a more luxurious vehicle image is implemented. In addition, the tailgate is unlatched in a non-contact manner without directly touching the sensor unit, such that the unlatching operation of the tailgate may be performed without repulsion even in a case where the tailgate is contaminated. 
     In addition, in a case where the obstacle is present in the vertical direction of the tailgate in the process in which the tailgate is opened, the obstacle is sensed through the sensor unit, such that the opening of the tailgate is stopped, thereby preventing the tailgate from colliding with the obstacle to be damaged. 
     Furthermore, the sensor unit performs the function of the tailgate switch in the state where the tailgate is closed and performs the function of the rear sensor sensing the rear obstacle in the process in which the tailgate is opened. Therefore, the tailgate switch and the rear sensor are integrated with each other, such that a cost and a weight may be reduced. 
     Although the present disclosure has been shown and described with respect to specific embodiments, it will be apparent to those having ordinary skill in the art that the present disclosure may be variously modified and altered without departing from the spirit and scope of the present disclosure as defined by the following claims.