Patent Publication Number: US-2023148037-A1

Title: Robot apparatus and controlling method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a bypass continuation application of International Application No. PCT/KR2022/ 013881, filed on Sep. 16, 2022, which is based on and claims priority to Korean Patent Application No. 10-2021-0151481, filed on Nov. 5, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     The disclosure relates to a robot apparatus, and more particularly, to a robot apparatus that has an improved structure such that a display that is rotatable with respect to a main body is supported stably by a stopper structure, and a controlling method thereof. 
     2. Description of Related Art 
     A display provided in a head part of a robot apparatus may be configured such that its display surface faces toward an upper direction while being mounted on a main body of the robot apparatus for performing a role of a guide or a kiosk at ordinary times, and configured such that its display surface faces toward a front direction by rotating in a direction of moving away from the head part of the robot apparatus for an interaction with a user. 
     In a state in which the display is rotated in a direction of moving away from the head part, when the robot apparatus is being driven, there is a problem that the display is shaken due to a vibration transmitted from the ground or a user’s touch operation. 
     SUMMARY 
     Example embodiments of the disclosure provide a robot apparatus that has an improved structure such that a display rotatable with respect to a main body is supported stably by a stopper structure, and a controlling method thereof. 
     According to an aspect of an example embodiment, there is provided a robot apparatus including: a main body; a display; a neck structure rotatably connected to the main body, and of which an end portion is connected to a rear surface of the display; a first driving device configured to rotate the neck structure around a first axis of the robot apparatus such that the display is positioned in a first location, in which a display surface of the display faces toward an upper direction, or a second location, in which the display surface faces toward a front direction; a stopper structure provided on the main body to be adjacent to the neck structure; and a second driving device configured to move the stopper structure toward the front direction or a rear direction such that the stopper structure is positioned in a supporting location in which the stopper structure contacts a rear surface of the neck structure, or a separated location, in which the stopper structure is spaced apart from the neck structure. 
     The first driving device may include: a shaft member rotatably connected to the main body, and provided along the first axis; a first motor configured to rotate the shaft member; and a rotation link connecting the neck structure and the shaft member. 
     The shaft member may be provided below the display. 
     The first driving device may further include: a first assistant link of which a first end portion is connected to the first motor; a second assistant link of which a first end portion is connected to a second end portion of the first assistant link; and a third assistant link of which a first end portion is connected to a second end portion of the second assistant link, of which a second end portion is connected to the shaft member, the third assistant link having a length longer than the first assistant link. 
     The stopper structure may be provided at a same height as the shaft member. 
     The second driving device may include a guide member, which contacts the stopper structure and configured to guide a moving path of the stopper structure. 
     The second driving device may include: a cam member of which a cross section has an ellipse shape, and which contacts the stopper structure; a second motor configured to rotate the cam member; a support which is fixed on the main body; and a pressure member of which a front end portion is connected to the stopper structure, and of which a rear end portion is connected to the support, the pressure member being configured to pressurize the stopper structure to the front direction. 
     The second motor may be configured to rotate the cam member in a first direction by 90 degrees, or rotate the cam member in a second direction opposite to the first direction by 90 degrees. 
     A radius of curvature of the rear surface of the neck structure may be identical to a radius of curvature of a front surface of the stopper structure. 
     An upper surface of the main body may extend from an upper end of a front surface of the main body toward the rear direction, and the display in the first location may be on the upper surface of the main body. 
     The main body may include a slot formed on the upper surface of the main body, and the neck structure may be withdrawn to an outside of the main body, or is inserted to an inside of the main body through the slot. 
     The robot apparatus may further include a processor configured to: based on a predetermined event occurring, control the second driving device such that the stopper structure moves to the separated location, and based on the stopper structure moving to the separated location, control the first driving device such that the neck structure rotates to a location corresponding to the predetermined event and stops after rotation, and based on the neck structure stopping, control the second driving device such that the stopper structure moves to the supporting location. 
     The robot apparatus may further include a third driving device configured to rotate the display around a second axis of the robot apparatus, and is supported by the rear surface of the display. 
     The robot apparatus may further include a traveling device configured to move the main body. 
     According to an aspect of an example embodiment, there is provided a method of controlling a robot apparatus including a main body, a display, a neck structure which connects the main body and the display, and a stopper structure provided adjacent to the neck structure, the method including: receiving a rotation signal; moving the stopper structure to a separated location in which the stopper structure is spaced apart from the neck structure; rotating the neck structure to a location corresponding to the rotation signal and stopping the neck structure after rotation; and moving the stopper structure to a supporting location in which the stopper structure contacts with the rear surface of the neck structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain example embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIGS.  1 A and  1 B  are perspective views of a robot apparatus according to an embodiment of the disclosure; 
         FIG.  2    is a perspective view illustrating a state wherein a display member is supported by a neck structure in a robot apparatus according to an embodiment of the disclosure; 
         FIG.  3    is a perspective view illustrating a state wherein a cover has been removed from a main body in  FIG.  2    according to an embodiment of the disclosure; 
         FIG.  4    is a perspective view illustrating a configuration of a first driving device in a robot apparatus according to an embodiment of the disclosure; 
         FIG.  5    is an exploded perspective view illustrating a configuration of a second driving device in a robot apparatus according to an embodiment of the disclosure; 
         FIG.  6    is a block diagram schematically illustrating a controlling process of a robot apparatus according to an embodiment of the disclosure; 
         FIG.  7    is a side view illustrating a state wherein a display member is disposed in a first location, and a stopper structure is disposed in a supporting location in a robot apparatus according to an embodiment of the disclosure; 
         FIG.  8    is a side view illustrating a state wherein the stopper structure in  FIG.  7    is moved backward from the supporting location to a separated location according to an embodiment of the disclosure; 
         FIG.  9    is a side view illustrating a state wherein the display member in  FIG.  8    rotated from the first location to a second location according to an embodiment of the disclosure; 
         FIG.  10    is a side view illustrating a state wherein the stopper structure in  FIG.  9    is moved forward from a separated location to the supporting location according to an embodiment of the disclosure; 
         FIG.  11    is a side view illustrating a state wherein a third driving device is supported on a rear surface of a display member in a robot apparatus according to an embodiment of the disclosure; and 
         FIG.  12    is a flow chart for illustrating a controlling method of a robot apparatus according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments that will be described below are exemplary embodiments for promoting understanding of the disclosure, and it should be understood that the disclosure may be implemented while being modified in various forms, unlike the embodiments described herein. In explaining the disclosure below, in case it is determined that detailed explanation of related known functions or components may unnecessarily confuse the gist of the disclosure, the detailed explanation and detailed illustration thereof will be omitted. Also, in the accompanying drawings, some components may not be illustrated in their actual scales, but may be illustrated in more enlarged sizes than their actual sizes, for promoting understanding of the disclosure. 
     Also, as terms used in this specification and the claims, general terms were selected in consideration of the functions described in the disclosure. However, the terms may vary depending on the intention of those skilled in the art who work in the pertinent field or legal or technical interpretation, or emergence of new technologies, etc. Also, there are some terms that were designated by the applicant on his own, and in such cases, the meaning of the terms may be interpreted as what is defined in this specification. If there is no specific definition of the terms, the meaning of the terms may be interpreted based on the overall content of this specification and technical knowledge common in the pertinent technical field. 
     In addition, in this specification, expressions such as “have,” “may have,” “include,” and “may include” denote the existence of such characteristics (e.g.: elements such as numerical values, functions, operations, and components), and do not exclude the existence of additional characteristics. 
     Also, in this specification, elements necessary for explanation of each embodiment of the disclosure are described, and thus elements are not necessarily limited thereto. Accordingly, some elements may be changed or omitted, or other elements may be added. Also, elements may be disposed to be dispersed in apparatuses independent from one another. 
     Further, while the embodiments of the disclosure will be described in detail with reference to the following accompanying drawings and the contents described in the accompanying drawings, it is not intended that the disclosure is restricted or limited by the embodiments. 
     Hereinafter, the disclosure will be described in more detail with reference to the accompanying drawings. 
       FIGS.  1 A and  1 B  are perspective views of a robot apparatus according to an embodiment of the disclosure.  FIG.  2    is a perspective view illustrating a state wherein a display member (or a display) is supported by a neck structure (or neck structure) in a robot apparatus according to an embodiment of the disclosure.  FIG.  3    is a perspective view illustrating a state wherein a cover has been removed from the main body in  FIG.  2    according to an embodiment of the disclosure. 
     Referring to  FIG.  1    to  FIG.  3   , a robot apparatus 1 according to an embodiment of the disclosure may include a main body  100 , a display member  200 , a neck structure (or neck structure)  300 , a first driving device  400 , a stopper structure  500 , and a second driving device  600 . 
     The main body  100  may include a driving part  101 , a body part  102 , and a head part  103  that are stacked in order from the lower side to the upper side. On the lower side of the driving part  101 , one or more wheels may be provided. In the driving part  101 , a traveling device  900  (refer to  FIG.  6   ) that moves the main body  100  may also be accommodated. Also, in the driving part  101 , one or more sensors (e.g., an optical sensor, an acceleration sensor, etc.) that are used for driving of the main body  100  may be accommodated. 
     The body part  102  may have thinner thickness than the driving part  101 , and may be extended from the driving part  101  toward a rear direction (e.g., -X axis direction in  FIG.  1 A ) while being tilted by a predetermined angle. On a front surface (e.g., a surface in a direction of X axis in  FIG.  1 A ) of the body part  102 , a display capable of providing information may be provided. 
     The head part  103  may be extended from an upper end of the body part  102  toward the rear direction while being tilted by a predetermined angle. That is, an upper surface  110  of the main body  100  may be formed to extend from an upper end  121  of the front surface  120  of the main body  100  toward the rear direction. The display member  200  may be mounted on the upper surface  110  of the main body  100  in a first location. The head part  103  may have a size corresponding to the display member  200 . 
     The display member  200  may be disposed in the first location wherein the display surface  210  faces toward an upper direction (e.g., Z axis direction in  FIG.  1 A ) or in a second location wherein the display surface  210  faces toward the front direction (e.g., X axis direction in  FIG.  1 B ). That is, the display member  200  may be disposed in the first location as shown in  FIG.  1 A , and may be disposed in the second location as shown in  FIG.  1 B . 
     When the display member  200  is disposed in the second location, the display member  200  may be disposed side by side with the front surface  120  of the main body  100 . That is, the display member  200  disposed in the second location may be disposed to be tilted toward the rear direction by a predetermined angle based on a vertical line. 
     The display member  200  may include a touch sensor and perform a role of a touch screen. Thus, a user may transmit a signal to the robot apparatus 1 by touching the display member  200 . 
     The display member  200  disposed in the first location may function as a kiosk. The display member  200  disposed in the second location may interact with a user, e.g., by providing an image expressing an emotion or a friendly facial expression. Also, the display member  200  may perform a motion of nodding or tilting for expressing an emotion. 
     The neck structure  300  may be connected rotatably to the main body  100 , and an end portion  310  of the neck structure  300  may be connected to a rear surface  220  of the display member  200 . The neck structure  300  may rotate around a horizontal rotation axis A1 of the main body  100 . The horizontal rotation axis A1 may be horizontal to the ground, and may be disposed along a Y axis direction in  FIG.  1 A . Accordingly, the display member  200  may move to the first location or the second location. 
     The main body  100  may include a slot  111  formed on the upper surface  110  of the main body  100 . The neck structure  300  may be withdrawn to the outside of the main body  100  or may be inserted to the inside of the main body  100  through the slot  111 . That is, when the display member  200  is disposed in the first location, the neck structure  300  may be inserted to the inside of the main body  100 , and when the display member  200  is disposed in the second location, the neck structure  300  may be withdrawn to the outside of the main body  100 . 
     The first driving device  400  may rotate the neck structure  300  around the horizontal rotation axis A1, such that the display member  200  is disposed in the first location or the second location. 
     The stopper structure  500  may be disposed in a supporting location that contacts a rear surface  320  of the neck structure  300  or in a separated location that is spaced apart from the neck structure  300 . The second driving device  600  may move the stopper structure  500  to the front direction (e.g., X axis in  FIG.  1 A ) or the rear direction (e.g., -X axis in  FIG.  1 A ), such that the stopper structure  500  is disposed in the supporting location or the separated location. 
     When the stopper structure  500  is in the supporting location, the neck structure  300  is not pushed to the rear direction, but is supported stably by the frictional force provided by the stopper structure  500 . Thus, the display member  200  may not be shaken by vibration that may occur while driving of the robot apparatus 1, e.g., vibration transmitted from the ground or vibration according to a user’s touch operation. 
     Also, when the stopper structure  500  is disposed in the separated location, the neck structure  300  may rotate freely in a state of being spaced apart from the stopper structure  500 . That is, when the display member  200  moves to the first location or the second location, the stopper structure  500  moves to the separated location, and thus the display member  200  and the neck structure  300  may rotate easily without being interrupted by the stopper structure  500 . 
       FIG.  4    is a perspective view illustrating a configuration of a first driving device in a robot apparatus according to an embodiment of the disclosure. 
     Referring to  FIG.  4   , the first driving device  400  may include a shaft member  410 , a first motor  420 , a rotation link  430 , a first assistant link  440 , a second assistant link  450 , and a third assistant link  460 . 
     The shaft member  410  may be connected rotatably to the main body  100 . Both ends of the shaft member  410  may be supported rotatably by two vertical ends  100   a ,  100   b  of the main body  100 . The shaft member  410  may be disposed along the horizontal rotation axis A1. That is, the shaft member  410  may define the horizontal rotation axis A1. 
     The shaft member  410  may be disposed in a lower location than the display member  200 . Accordingly, the display member  200  may rotate to the first location or the second location without interfering with the main body  100 . 
     The first motor  420  may rotate the shaft member  410 . The rotation link  430  may include a rotation link  430  connecting the neck structure  300  and the shaft member  410 . That is, the shaft member  410 , the rotation link  430 , the neck structure  300 , and the display member  200  may rotate integrally at the same angular velocity. 
     One end  441  of the first assistant link  440  may be connected to the first motor  420 . One end  451  of the second assistant link  450  may be connected to the other end  442  of the first assistant link  440 . One end  461  of the third assistant link  460  may be connected to the other end  452  of the second assistant link  450 , and the other end  462  may be connected to the shaft member  410 . 
     That is, three assistant links connected in series may connect the first motor  420  and the shaft member  410 . 
     The third assistant link  460 , the shaft member  410 , the rotation link  430 , and the neck structure  300  may be connected integrally, and all of them may rotate around the horizontal rotation axis A1 at the same angular velocity. 
     The third assistant link  460  may have longer length than the first assistant link  440 . Accordingly, the third assistant link  460  may rotate at slower angular velocity than the first assistant link  440 , and thus the torque generated from the first motor  420  may be amplified and transmitted to the third assistant link  460 . The display member  200  and the neck structure  300  may rotate effectively through the first motor  420  having a small capacity. 
       FIG.  5    is an exploded perspective view illustrating a configuration of a second driving device in a robot apparatus according to an embodiment of the disclosure. 
     Referring to  FIG.  5   , the stopper structure  500  may include a guide rod  502 , a braking part  510 , and a moving part  520 . The second driving device  600  may include a guide member  610 , a cam member  620 , a second motor  630 , a support  640 , and a pressure member  650 . 
     The guide rod  502  may be inserted into a first hole  641  of the support  640  that will be described below, and may be disposed coaxially with the pressure member  650 . The pressure member  650  has a bigger diameter than the first hole  641 , and thus it may be supported by the front surface of the support  640 . 
     The guide rod  502  may be disposed side by side with the guide member  610 , and may be disposed to be enclosed by the pressure member  650 . The pressure member  650  may not be detached from a designated location by the guide rod  502 . 
     The braking part  510  may be disposed in the front end part of the stopper structure  500 , and may be disposed to face the neck structure  300 . The braking part  510  may be an area that selectively contacts the neck structure  300 . 
     The moving part  520  may be disposed in the rear end part of the stopper structure  500 , and may have smaller width length than the braking part  510 . The moving part  520  may be an area that contacts the second motor  630  and receives the moving force to the rear direction from the second motor  630 . The moving part  520  may move to the front direction or the rear direction in a state of penetrating through a second hole  642  of the support  640 . 
     The guide member  610  may contact the stopper structure  500  and guide a moving path of the stopper structure  500 . The guide member  610  may be fixedly disposed on a horizontal plate  100   c  of the main body  100 . 
     The guide member  610  may be engaged with a slider disposed on a lower end of the stopper structure  500  and support the stopper structure  500  toward an upper side of the stopper structure  500 , and guide the stopper structure  500  such that the stopper structure  500  moves to the front direction or the rear direction along the guide member  610 . 
     The cross section of the cam member  620  may have an ellipse shape, and the cam member  620  may contact the stopper structure  500 . The second motor  630  may rotate the cam member  620 . 
     That is, the lengths of the long axis and the short axis of the cam member  620  may be different from each other. Accordingly, when the cam member  620  rotates in a first direction R1 (refer to  FIG.  8   ) by 90 degrees, the rear end of the moving part  520  that contacts the cam member  620  may be pushed to the rear direction. 
     The rear end of the moving part  520  may include a projection  521  that is projectingly formed toward the second motor  630 . The projection  521  of the moving part  520  may have a conical shape, and the projection  521  may always circumscribe around the cam member  620 . 
     If the cam member  620  pushes the stopper structure  500  to the rear direction as it rotates, the pressure member  650  may be compressed by the support  640 . Afterwards, when the cam member  620  rotates in a second direction R2 (refer to  FIG.  10   ) opposite to the first direction R1 by 90 degrees, the pressure member  650  that was compressed may push the stopper structure  500  to the front direction. Accordingly, the stopper structure  500  may move from the separated location to the supporting location. 
     The support  640  may be fixedly disposed on the main body  100 . The support  640  may be fixed on the horizontal plate  100   c  of the main body  100 . The front surface of the support  640  may be disposed to face the braking part  510  on the front end of the stopper structure  500 . 
     The front end  651  of the pressure member  650  may be connected to the stopper structure  500 , and its rear end  652  may be connected to the support  640 , and the pressure member  650  may pressurize the stopper structure  500  to the front direction. Specifically, the pressure member  650  is a compression spring, and its front end  651  may be connected to the rear surface of the braking part  510 , and its rear end  652  may be connected to the front surface of the support  640 . 
       FIG.  6    is a block diagram schematically illustrating a controlling process of a robot apparatus according to an embodiment of the disclosure. 
     Referring to  FIG.  6   , a robot apparatus 1 may include a first driving device  400 , a second driving device  600 , a processor  700 , a third driving device  800 , and a traveling device  900 . The traveling device  900  may include a known traveling mechanism (e.g., a motor or a wheel) to move the main body  100 . 
     The processor  700  may control the overall operations of the robot apparatus 1. For this, the processor  700  may include one or more of a central processing unit (CPU), an application processor (AP), or a communication processor (CP). Also, the processor  700  may be a micro control unit (MCU). 
     The processor  700  may control hardware and/or software components connected to the processor  700  by driving an operation system or an application program, and perform various kinds of data processing and operations. Also, the processor  700  may load an instruction or data received from at least one of other components on a volatile memory and process them, and store various data in a non-volatile memory. 
     When a predetermined event occurs, the processor  700  may control the second driving device  600  such that the stopper structure  500  moves to the separated location. 
     The predetermined event may be a situation wherein a user transmits a rotation signal of the display member  200  to the processor  700  through an input device. Alternatively, the predetermined event may be a situation wherein a specific condition (e.g., a specific time, weather, etc.) for the display member  200  to rotate is satisfied without a separate input. 
     The input device may include, for example, a touch panel, a (digital) pen sensor, a key, or an ultrasonic input device. The touch panel, the pen sensor, and the key may be provided in the display member  200 . 
     The touch panel may use, for example, at least one method among a capacitive method, a decompressive method, an infrared method, or an ultrasonic method. Also, the touch panel may further include a control circuit. The touch panel may further include a tactile layer, and provide a tactile response to a user. The (digital) pen sensor may be, for example, a part of the touch panel, or include a separate sheet for recognition. The key may include, for example, a physical button, an optical key, or a keypad. The ultrasonic input device may, for example, detect an ultrasonic wave generated at an input tool through a microphone, and identify data corresponding to the detected ultrasonic wave. 
     Also, the input device may be a terminal device such as a remote control, a smart watch, a smart band, a wireless headset, a mobile phone, a smartphone, a tablet, etc. 
     When the stopper structure  500  moves to the separated location, the processor  700  may control the first driving device  400  such that the neck structure  300  rotates to a location corresponding to the predetermined event and then stops. 
     When the neck structure  300  stops, the processor  700  may control the second driving device  600  such that the stopper structure  500  moves to the supporting location. 
       FIG.  7    is a side view illustrating a state wherein a display member is disposed in a first location, and a stopper structure is disposed in a supporting location in a robot apparatus according to an embodiment of the disclosure. 
     Referring to  FIG.  7   , the radius of curvature R of the rear surface  320  of the neck structure  300  may be identical to the radius of curvature R of the front surface  501  of the stopper structure  500 . Accordingly, the rear surface  320  of the neck structure  300  and the front surface  501  of the stopper structure  500  come to contact in the largest area possible. Thus, the frictional force between the neck structure  300  and the stopper structure  500  are increased, and the neck structure  300  may be supported by the stopper structure  500  more stably. 
     The stopper structure  500  may be disposed at the same height as the shaft member  410 . That is, the stopper structure  500  may support the neck structure  300  at the same height as the shaft member  410  defining the center of rotation of the neck structure  300 . Accordingly, the pressurizing force of the stopper structure  500  to the front direction may be transmitted to the neck structure  300  with the smallest loss possible. 
     In the state of  FIG.  7   , the stopper structure  500  is pressurized to the front direction by the pressure member  650 , and the neck structure  300  is also pressurized to the front direction by the stopper structure  500 , and thus the first and second driving devices  400 ,  600  may not consume standby currents. 
       FIG.  8    is a side view illustrating a state wherein the stopper structure in  FIG.  7    is moved backward from the supporting location to the separated location according to an embodiment of the disclosure. 
     Referring to  FIG.  8   , the second driving device  600  may move the stopper structure  500  from the supporting location to the separated location. That is, if the second motor  630  rotates the cam member  620  in an ellipse shape in the first direction R1 by 90 degrees, the stopper structure  500  contacting the cam member  620  may be pushed to the rear direction. Here, the pressure member  650  may be compressed. 
     In the state of  FIG.  8   , the second driving device  600  may use a current only when rotating the cam member  620  in the first direction R1 by 90 degrees. 
       FIG.  9    is a side view illustrating a state wherein the display member in  FIG.  8    is rotated from a first location to a second location according to an embodiment of the disclosure. 
     Referring to  FIG.  9   , the first driving device  400  may be controlled such that, when the stopper structure  500  moves to the separated location, the neck structure  300  moves to a location corresponding to the predetermined event and then stops. That is, the neck structure  300  may rotate easily without contacting the stopper structure  500  disposed in the separated location. 
     In the state of  FIG.  9   , the second driving device  600  may not use a current, but only the first driving device  400  may use a current for the rotation of the display member  200 . 
       FIG.  10    is a side view illustrating a state wherein the stopper structure in  FIG.  9    is moved forward from a separated location to a supporting location according to an embodiment of the disclosure. 
     Referring to  FIG.  10   , when the neck structure  300  stops, the second driving device  600  may move the stopper structure  500  from the separated location to the supporting location. That is, if the cam member  620  rotates in the second direction R2 opposite to the first direction R1 by 90 degrees by the second motor  630 , the pressure member  650  that was compressed may push the stopper structure  500  to the front direction. Accordingly, the stopper structure  500  may move from the separated location to the supporting location. 
     Afterwards, the stopper structure  500  is pressurized to the front direction by the pressure member  650 , and the neck structure  300  is also pressurized to the front direction by the stopper structure  500 , and thus the first and second driving devices  400 ,  600  may not consume standby currents. 
     That is, referring to  FIG.  7    to  FIG.  10   , use of currents by the first and second driving devices  400 ,  600  may be minimized by the ellipse shape of the cam member  620  and the elastic force of the pressure member  650 . 
       FIG.  11    is a side view illustrating a state wherein a third driving device is supported on a rear surface of a display member in a robot apparatus according to an embodiment of the disclosure. 
     Referring to  FIG.  11   , the robot apparatus 1 may further include a third driving device  800  which rotates the display member  200  around an additional rotation axis A2, and is supported by the rear surface  220  of the display member  200 . For example, the third driving device  800  may include a motor capable of rotating the display member  200 . 
     The additional rotation axis A2 may be horizontal along the front and rear directions (that is, X axis direction in  FIG.  1 A ). The display member  200  may roll while rotating around the additional rotation axis A2. Accordingly, the display member  200  may perform various interaction functions with a user. 
     Also, even if the third driving device  800  is supported by the rear surface  220  of the display member  200  and its center of gravity rises, the neck structure  300  is supported stably by the stopper structure  500 . Thus, the display member  200  may not be shaken by vibration that may occur while driving of the robot apparatus 1, e.g., vibration transmitted from the ground or vibration according to a user’s touch operation. 
       FIG.  12    is a flow chart for illustrating a controlling method of a robot apparatus according to an embodiment of the disclosure. 
     Referring to  FIG.  12   , a controlling method of the robot apparatus 1 according to an embodiment of the disclosure may include operations of receiving a rotation signal (S 10 ), the stopper structure  500  moving to a separated location wherein the stopper structure  500  is spaced apart from the neck structure  300  (S 20 ), the neck structure  300  rotating to a location corresponding to the rotation signal and then stopping (S 30 ), and the stopper structure  500  moving to a supporting location contacting the rear surface  320  of the neck structure  300  (S 40 ). 
     Accordingly, when the stopper structure  500  is in the supporting location, the neck structure  300  is not pushed to the rear direction, but is supported stably by the frictional force provided by the stopper structure  500 . Thus, the display member  200  may not be shaken by vibration, e.g., transmitted from the ground or vibration according to a user’s touch operation while driving of the robot apparatus 1. 
     Also, when the stopper structure  500  is disposed in the separated location, the neck structure  300  may rotate freely in a state of being spaced apart from the stopper structure  500 . That is, when the display member  200  moves to the first location or the second location, the stopper structure  500  moves to the separated location, and thus the display member  200  and the neck structure  300  may rotate easily without being interrupted by the stopper structure  500 . 
     While example embodiments of the disclosure have been shown and described, the disclosure is not limited to the aforementioned specific embodiments, and it is apparent that various modifications can be made by those having ordinary skill in the art to which the disclosure belongs, without departing from the gist of the disclosure as claimed by the appended claims, and such modifications are within the scope of the descriptions of the claims.