Abstract:
A space scanner for an autonomous mobile device can obtain spatial data by scanning not only in the horizontal direction but also in the vertical direction of the mobile device using a mirror configured to rotate as well as to tilt and thereby can ensure autonomous driving.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 2008-93407 filed on Sep. 23, 2008, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a space scanner for an autonomous mobile device, more particularly, which can obtain spatial data by scanning not only in the horizontal direction but also in the vertical direction of the mobile device using a mirror configured to rotate as well as to tilt. 
     2. Description of the Related Art 
     An autonomous mobile (walking) device such as a mobile robot detects surrounding objects and measures distances from the objects using laser, supersonic waves or the like in order to locate its position and determine the direction to move. 
     Laser range finding is known as a most accurate method for measuring the distance to an object, particularly, by detecting a laser beam reflecting from the object and measuring the time taken for the laser beam to travel to the object and back. 
     A conventional autonomous mobile device adopting such a laser range finding technique scans using laser beams emitted directly along a two-dimensional horizontal plane. Accordingly, the autonomous mobile device can detect surrounding objects and measure the distance from the objects only if the objects are located at a specific height corresponding to a laser emitter. 
     That is, detectable objects are limited to those onto which the laser beams are emitted and to those which are located at the same horizontal plane of the laser emitter. Thus, it is impossible to scan other ranges and distance information on only a specific horizontal plane can be obtained. 
     However, while consumer demands on autonomous mobile devices capable of performing more accurate driving and more various operations are increasing, the distance information only on a specific horizontal plane cannot sufficiently ensure safety and functionality. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention provides a space scanner for an autonomous mobile device, which can obtain spatial data necessary for autonomous driving by scanning not only in the horizontal direction but also in the vertical direction of the mobile device using a mirror configured to rotate as well as to tilt. 
     According to an aspect of the present invention, the space scanner for an autonomous mobile device may include a rotation driving unit; a mirror coupled with the rotation driving unit so as to tilt with respect thereto; a gear unit converting the direction of a rotating force from the rotation driving unit; a cam member coupled with the gear unit via a shaft on which the cam member is mounted, the cam member rotating by the rotating force transmitted via the gear unit; and a tilt driving unit having an underside surface performing surface contact with the cam member, wherein the tilt driving unit vertically reciprocates by rotation of the cam member to tilt the mirror. 
     In an exemplary embodiment, the rotation driving unit may include a rotary electric motor; and a vertical rotary shaft having one end axially coupled with the rotary electric motor and the other end hinged to the mirror. 
     In another exemplary embodiment, the gear unit may include a first gear rotating by the rotating force from the rotation driving unit; and at least one second gear meshed with the first gear to rotate on a horizontal rotary shaft, which extends perpendicular to a vertical center of rotation of the first gear. 
     In a further exemplary embodiment, the gear unit may further include at least one support through which the horizontal rotary shaft extends, wherein the support is coupled with the horizontal rotary shaft to allow the second gear to rotate in mesh with the first gear. 
     In a further another exemplary embodiment, the horizontal rotary shaft has one end connected to the second gear and the other end connected to the cam member, and is supported by the support. 
     In another exemplary embodiment, the gear unit may include bevel gears. 
     In a further exemplary embodiment, the cam member has a circular or elliptical shape. 
     In another exemplary embodiment, the cam member is shaft-connected with the gear unit such that the center of rotation is eccentric to the center of the cam member. 
     In a further exemplary embodiment, the tilt driving unit may include a vertically movable frame driven to vertically reciprocate by the cam member, which is placed under the vertically movable frame, wherein the vertically movable frame has a central opening of a predetermined size in the central portion thereof; a rotary frame having a through-hole of a predetermined size that allows the gear unit to pass through, wherein the rotary frame is received inside the central opening and is rotatably coupled with the vertically movable frame; and a rod having one end hinged to the rotary frame and the other end hinged to the mirror. 
     In a further another exemplary embodiment, the tilt driving unit further includes a guide shaft guiding the vertically movable frame to vertically reciprocate. 
     According to embodiments of the invention, the space scanner for an autonomous mobile device can obtain spatial data necessary by scanning not only in the horizontal direction but also in the vertical direction of the mobile device using a mirror configured to rotate as well as to tilt, and thereby ensure more precise and safe autonomous driving. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view illustrating a space scanner for an autonomous mobile device according to an exemplary embodiment of the invention; 
         FIG. 2  is a perspective view of the space scanner for an autonomous mobile device shown in  FIG. 1 ; 
         FIG. 3  is a perspective view illustrating a gear unit of the space scanner for an autonomous mobile device shown in  FIG. 1 ; 
         FIG. 4  is a perspective view illustrating a tilt driving unit of the space scanner for an autonomous mobile device shown in  FIG. 1 ; 
         FIG. 5  is a perspective view illustrating tilt driving unit shown in  FIG. 4 , to which a mirror is hinged; and 
         FIGS. 6A through 6C  are schematic views illustrating respective operation stages of the space scanner for an autonomous mobile device shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A space scanner for an autonomous mobile device according to the present invention will now be described hereinafter more fully with reference to the accompanying drawings, in which exemplary embodiments thereof are shown. 
       FIG. 1  is a cross-sectional view illustrating a space scanner for an autonomous mobile device according to an exemplary embodiment of the invention,  FIG. 2  is a perspective view of the space scanner for an autonomous mobile device shown in  FIG. 1 ,  FIG. 3  is a perspective view illustrating a gear unit of the space scanner for an autonomous mobile device shown in  FIG. 1 ,  FIG. 4  is a perspective view illustrating a tilt driving unit of the space scanner for an autonomous mobile device shown in  FIG. 1 , and  FIG. 5  is a perspective view illustrating tilt driving unit shown in  FIG. 4 , to which a mirror is hinged. 
     As shown in  FIGS. 1 and 2 , the space scanner for an autonomous mobile device according to an exemplary embodiment of the invention includes a rotation driving unit  10 , a mirror M, a gear unit  20 , cam members  30  and a tilt driving unit  40 . 
     The rotation driving unit  10  serves to generate a rotating force for driving the space scanner for an autonomous mobile device of the invention. The rotation driving unit  10  has a rotary motor  11  provided in the lower portion thereof to rotate a vertical rotary shaft  12  when electric power is applied thereto. The rotary motor  11  can preferably be contained in a housing to be protected from outside. 
     The vertical rotary shaft  12  has a circular columnar structure to be rotated at a predetermined rate by the rotary motor  11 , wherein one end thereof is axially coupled with the rotary motor  11  and the other end thereof is hinged to the mirror M allowing the mirror M to tilt. 
     Accordingly, the rotating force generated by the rotary motor  11  rotates the vertical rotary shaft  12  and the mirror M coupled with the vertical rotary shaft  12  while driving the gear unit  20 , the cam members  30  and the tilt driving unit  40 , provided between the mirror M and the rotary motor  11 , to thereby tilt the mirror M. 
     In the meantime, the gear unit  20  changes the direction of the rotating force from the rotation driving unit  10  to rotate the cam members  30 , thereby driving the tilt driving unit  40 . 
     As shown in  FIG. 3 , the gear unit  20  includes a first gear  21  and a pair of second gears  22 , in which gear teeth cut on conically-shaped gear bodies are in mesh at 90 degrees. 
     The first gear  21  is fitted onto the vertical rotary shaft  12  of the rotation driving unit  10  so as to coaxially rotate along with the vertical rotary shaft  12  by the rotating force of the rotary motor  11 . 
     The second gears  22  are in mesh with the first gear  21  at substantially 90 degrees. Thus, each of the second gears  22  meshed with the first gear  21  rotates on a horizontal rotary shaft  23  extending perpendicular to the vertical axis of rotation of the first gear  21 . 
     Since the second gears are in mesh with the first gear at the right angle, the rotating force from the rotary motor  11  can be transmitted along the horizontal rotary shafts  23  extending perpendicular to the vertical rotary shaft  12 . 
     The gear unit  20  can preferably be implemented with bevel gears. 
     In addition, the gear unit  20  also includes one or more supports  24  through which the horizontal rotary shafts  23  extend such that the second gears  22  can rotate in mesh with the first gear  21 . 
     While the two second gears  22  are meshed with both sides of the first gear  21  and are supported by the supports  24  according to the description of this embodiment of the invention, this is not intended to be limiting. Rather, the number of the second gears  22  can be one or more than two. 
     In the meantime, each of the cam members  30  is coupled with the gear unit  20  via a shaft on which the cam member  30  is mounted. The cam members  30  are rotated by the rotating force transmitted via the gear unit  20 , thereby reciprocally raising and lowering the tilt driving unit  40  in the vertical direction. 
     As shown in  FIGS. 1 through 3 , each of the cam members  30  is configured as a circular or elliptical plate structure of a predetermined thickness. 
     The cam member  30  is axially connected with the second gear  22  via the horizontal rotary shaft  23  on which the cam member  30  is mounted so as to rotate following the rotation of the second gear  22 . 
     Specifically, the horizontal rotary shaft  23  is connected at one end thereof with the second gear  22  and at the other end thereof with the cam member  30 , and is supported by the support  24  such that the second gear  22  and the cam member  30  can rotate on the horizontal rotary shaft  23 . 
     The cam member  30  can be shaft-connected with the horizontal rotary shaft  23  of the gear unit  20  such that the center of rotation is not identical with but is eccentric to the center of the cam member  30 . 
     When the cam member  30  rotates on the horizontal rotary shaft  23  as the center of rotation, a radius of rotation (i.e., a shorter radius) defined by a first radius L 1  from the horizontal rotary shaft  23  differs from a radius of rotation (i.e., a longer radius) defined by a second radius L 2  from the horizontal rotary shaft  23 . This difference in radius corresponds to the difference in length between the first radius and the second radius. 
     The difference in length corresponds to a vertical travel distance of the tilt driving unit  40 , which will be described below. 
     In the tilt driving unit  40 , the underside surface is in surface contact with the cam member  30 . The tilt driving unit  40  is caused to vertically reciprocate by rotation of the cam member  30 , thereby driving the mirror M to tilt. 
     As shown in  FIGS. 4 and 5 , the tilt driving unit  40  includes a vertically movable frame  41 , a rotary frame  42  and a rod  46  of a predetermined length. 
     The vertically movable frame  41  is driven to vertically reciprocate by the cam member  30 , which is placed under the vertically movable frame  41 , and has a central opening  43  of a predetermined size in the central portion thereof. 
     The rotary frame  42  is received inside the central opening  43  of the vertically movable frame  41  and is rotatably coupled with the vertically movable frame  41 . The rotary frame  42  has a through-hole  44  in the central portion thereof, through which the gear unit  20  can pass. 
     The tilt driving unit  40  has guide shafts  45  on the outer circumference of the vertically movable frame  41  to guide the vertically movable frame  41  to vertically reciprocate along a predetermined track. 
     While the vertically movable frame  41  and the through-hole  44  have a circular shape according to the description of the exemplary embodiment of the invention, this is not intended to be limiting. Rather, the vertically movable frame  41  and the through-hole  44  can have a variety of shapes such as a quadrangle. 
     The through-hole  44  can also be located in the central portion of the vertically movable frame  41 , with the size thereof being smaller than that of the central opening  43 . 
     In addition, a bearing can be provided between the rotary frame  42  and the vertically movable frame  41  such that the rotary frame  42  received inside the central opening  43  can smoothly rotate inside the vertically movable frame  41 . 
     The rod  46  is a link member having one end hinged to the rotary frame  42  and the other end hinged to the mirror M. 
     Below, with reference to  FIG. 6 , a description will be given of a structure that allows the mirror to rotate and tilt according to the invention. 
       FIGS. 6A through 6C  are schematic views illustrating respective operation stages of the space scanner for an autonomous mobile device shown in  FIG. 1 . 
     As shown in  FIG. 6A , when the vertically movable frame  41  is in surface contact with the cam member  30  at the height (length) of the first radius (L 1 ) of the cam member  30 , the tilt driving unit  40  is located at the lowest position. 
     The mirror M is then pulled directly downwards by the rod  46  such that the inclination θ of the mirror M becomes 45 degrees or more with respect to the horizon. 
     Then, as shown in  FIG. 6B , when the cam member  30  is rotated to the extent that the vertically movable frame  41  comes into surface contact with the cam member  30  at the middle height (length) between the first radius (L 1 ) and the second radius (L 2 ), the tilt driving unit  40  is located at the middle height. 
     In this case, the mirror M is pushed directly upwards by the rod  46  such that the inclination θ of the mirror M becomes about 45 degrees with respect to the horizon. 
     Next, as shown in  FIG. 6C , when the cam member  30  is rotated to the extent that the vertically rotatable frame  41  is in surface contact with the cam member  30  at the height (length) of the second radius (L 2 ) of the cam member  30 , the tilt driving unit  40  is located at the highest position. 
     In this case, the mirror M is pushed directly upwards by the rod  46  such that the inclination θ of the mirror M becomes 45 degrees or less with respect to the horizon. 
     The tilting motion of the mirror M is repeated as the cam mirror  30  continues to rotate in the range expressed by the following relation: 0&lt;θ&lt;90. The range of the inclination θ can be adjusted by changing the length of the rod  46 . 
     Furthermore, the rotation of the mirror M can be equally carried out as the vertical rotary shaft  12  continues to rotate. 
     While the present invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.