Abstract:
A 3D laser range finder sensor is disclosed wherein the sensor comprises: a reflection body for reflecting an emitted light and an incident light; a horizontal rotation body for rotating the reflection body; a vertical moving body for tilting the reflection body; and a body irradiating the emitted light to the reflection body and receiving the incident light through reflection from the reflection body.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §119 of Korean Application Number 10-2008-0085234, filed Aug. 29, 2008, which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    The following disclosure relates to a three dimensional (3D) laser range finder (LRF) sensor, and more particularly to a 3D laser range finder sensor capable of determining presence or absence of a target object, a position of the object and a distance to the object on a 3D space by emitting light to the object and receiving the light reflected from the object. 
         [0003]    A laser range finder (LRF) sensor generally including a light source, a rotation body and a sensor is operated based on the principle of sending a light emitted from a light source toward the target object, and then receiving and detecting, by a sensor, a signal reflected off the target object, whereby a traveling time of the signal is measured and the distance to the target object is obtained using a series of numerical calculations. 
         [0004]    The rotation body is capable of rotating the light source and the sensor to conduct all the performances within a given angle. The LRF sensor is largely configured to perform a distance determination of a portion in the first dimension. That is, the LRF sensor is generally configured to scan a horizontal object. 
       BRIEF SUMMARY 
       [0005]    In order to realize a 3D LRF sensor capable of horizontal and vertical direction scanning, a reflection mirror inside a laser range finder structure must be able to perform a horizontal adjustment and an inclination adjustment as well, and therefore, there is required a structural method of simply realizing the adjustment. An exemplary embodiment of the present invention is to provide a 3D laser range finder sensor capable of spatial recognition in the horizontal direction and the vertical direction as well. 
         [0006]    In one general aspect of the present invention, a 3D laser range finder sensor is provided comprising: a reflection body for reflecting an emitted light and an incident light; a horizontal rotation body for rotating the reflection body; a vertical moving body for tilting the reflection body; and a body irradiating the emitted light to the reflection body and receiving the incident light through reflection from the reflection body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an external perspective view of a 3D laser range finder (LRF) sensor and an internal perspective view of an LRF structure according to an exemplary embodiment of the present invention. 
           [0008]      FIG. 2  is an exploded cross-sectional view of an LRF structure according to an exemplary embodiment of the present invention. 
           [0009]      FIG. 3  is a combined cross-sectional perspective view of an LRF structure in which a horizontal rotation body, a vertical moving body and a reflection body are combined. 
           [0010]      FIG. 4  is a graphic illustrating a rotated shape of a mirror according to an exemplary embodiment of the present invention. 
           [0011]      FIG. 5  is a graphic illustrating a combined shape of a rear part coupler according to an exemplary embodiment of the present invention. 
           [0012]      FIG. 6  is a graphic illustrating a changed shape of an inclination of a mirror according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
         [0014]      FIG. 1  is an external perspective view of a 3D laser range finder (LRF) sensor and an internal perspective view of an LRF structure according to an exemplary embodiment of the present invention. 
         [0015]    The 3D laser range finder (LRF) sensor may include a body  110  and an LRF structure  115 , where the body  110  may include a light reception element sensing an incident light signal as an incident light, a light collection lens collecting the incident light signal to the light reception element, and a light emitting element emitting light using a laser. 
         [0016]    The light emitted from the light emitting element is reflected by a reflection mirror  121  and emitted to outside as a signal light. At this time, a point to which the light is emitted varies according to a rotation position and an inclination of the mirror  121 . In a case where the emitted light hits an object and returns as a signal light, the signal light is reflected by the mirror to be incident on the body  110 , and incident on the light reception element via the light collection lens of a fixed body. As a result, the body  110  irradiates the emitted light, emits the light via the mirror, and performs a scanning of collecting via the mirror the incident light returning from the object after hitting the object. 
         [0017]    The LRF structure  115  performs a 3D spatial recognition (distance recognition) via the rotation and inclination of the mirror. The mirror is connected via a base plate  123  and a mirror support, where the mirror is rotated in response to the rotation of the base plate  123 . The mirror is moved along a hinge by way of a vertical driving link connected to the vertically-moving link bases to show an inclination change. 
         [0018]    At this time, the changes of rotation and inclination of the mirror are simultaneously implemented to perform a 3D scanning. The mirror also reflects the emitted light and the incident light to enable a 3D spatial recognition. To this end, the LRF structure may include a horizontal rotation body, a vertical moving body, and a reflection body. 
         [0019]      FIG. 2  is an exploded cross-sectional view of an LRF structure according to an exemplary embodiment of the present invention, and  FIG. 3  is a combined cross-sectional perspective view of an LRF structure in which a horizontal rotation body, a vertical moving body, and a reflection body are combined. 
         [0020]    The horizontal rotation body  140  is formed at a bottom surface of the reflection mirror  121  and rotates a hollow pipe  142  via a horizontal driving motor  141  operating just like a spindle motor. A rotation shaft of the horizontal driving motor is a hollow axle comprising a hollow pipe  142  that is hollow in its center. An emitted light or an incident light passing the mirror  121  via an interior of the hollow pipe is transmitted to outside or to the body through the interior of the hollow pipe. 
         [0021]    In order to implement the rotation of the hollow pipe  142 , the horizontal driving motor  141  encompasses a lower distal end of the hollow pipe to realize the rotation of the hollow pipe  142 . An upper distal end of the hollow pipe  142  is fixed at the base plate of a reflection body  120 , where the base plate  123  is formed with a mirror support  122  which a support axle connectively supporting the mirror  121 . 
         [0022]    The hollow pipe  142  is rotated  360  degrees in response to the rotation of the horizontal driving motor, and the rotation of the base plate  123  connected to the hollow pipe is realized by the rotation of the hollow pipe  142 . The rotation of the base plate  123  enables the rotation of the mirror support  122  connected to the base plate  123  and, resultantly, the rotation of the mirror  121  is performed by the rotation of the mirror support  122 . Two mirror supports  122  are configured, i.e., one mirror support  122  at each side of a diameter of the base plate  123 . 
         [0023]    Each scanning image that is a result of the rotation of the mirror  121  is shown in  FIGS. 4(   a ) and  4 ( b ), where  FIG. 4(   a ) is a graphic illustrating a measured image of the 3D LRF sensor at a particular position, and  FIG. 4(   b ) is a graphic illustrating a measured image of the 3D LRF sensor at a position where a mirror is rotated 180° from a position of  FIG. 4(   a ). 
         [0024]    Referring to  FIG. 4(   a ), light emitted from a light emitting element inside the body is emitted to the right side via the mirror, such that a scanning is realized where the incident light enters from the right side, passes the mirror, and enters into the light reception element within the body. 
         [0025]    Meanwhile, in a case where the mirror is rotated 180° by the rotation of the rotation body, as shown in  FIG. 4(   b ), the light emitted from the light emitting element passes the mirror and is emitted to the left, whereby a scanning is realized in which the incident light enters from the left side, passes the mirror and enters the light reception element inside the body. 
         [0026]    Meanwhile, a vertical moving body  130  may include a linear stepping motor and a vertical driving motor and is disposed at an outside of the hollow pipe  142 . The vertical moving body  130  may include an external body  131 , a screw  132 , a link base  134 , and a bearing  133 . 
         [0027]    The external body  131  is formed therein with a screw thread, and the screw  132  is rotated along the screw thread to vertically move along the hollow pipe  142 . The link base  134  wraps an outer periphery at an upper end of the screw  132  to make it possible to rotate along the outer periphery of the upper end of the screw  132 . The bearing  133  is interposed between the upper end of the screw  132  and the link base  134  to absorb a difference between a rotation speed of the hollow pipe  142  and that of the screw  132 . 
         [0028]    To be more specific, in a case wherein the vertical driving motor is rotated by a control which is separate from that of the horizontal rotation body, the screw  132  inside the external body  131  is rotated along the screw thread and moves vertically. The screw  132  formed inside is so configured as to maintain a predetermined gap from the hollow pipe, whereby the screw  132  is rotated along the screw thread of the external body  131  apart from the hollow pipe to vertically rotate the screw. 
         [0029]    The bearing  133  is disposed at an upper outer periphery of the screw, and the link base  134  is disposed on the bearing. The link base  134  is connected to a vertical driving link  124  of the reflection body. The vertical driving link  124  serves to adjust the inclination of the mirror, where a vertical axle  124 a of the vertical driving link is also vertically moved in response to the vertical movement of the link base  134  disposed at an outer periphery of the screw. 
         [0030]    That is, when the screw is vertically moved, the link base  134  connected to the screw is vertically moved at the same time and, as a result, the vertical axle  124 a of the vertical driving link  124  connected to the link base  134  is also vertically moved to adjust the inclination of the mirror  121 . 
         [0031]    Meanwhile, the link base  134  is vertically moved by the rotation of the screw and rotated by the horizontal driving motor  141  as well. That is, in a case where the mirror  121  is rotated by the rotation of the base plate  123  connected to a central axle, the vertical driving link  124  is also rotated as a result of the rotation of the mirror  121 , and the link base  134  is also rotated by the rotation of the vertical driving link  124 . 
         [0032]    At this time, there may be generated a speed difference between the rotation of the link base in response to the rotation of the horizontal driving motor  141  and the rotation of the screw  132 , and the speed difference can be buffered by the bearing  133  interposed between the link base  134  and the screw  132 . 
         [0033]    That is, the bearing  133  serves to absorb the rotation speed difference between the rotation speed of the hollow pipe  142  in response to the rotation of the horizontal driving motor and the rotation of the vertical driving motor, whereby a smooth operation can be performed. 
         [0034]    The reflection body  120  functions to reflect the emitted light and the incident light by vertically moving the emitted light and the incident light 360°. The reflection body  120  may include a mirror  121 , a mirror support  122 , a base plate  123 , and a vertical driving link  124 . 
         [0035]    The mirror  121  is operated on the principle of being changed in rotation and inclination thereof, and serves to reflect the emitted light and the incident light. The mirror support  122  functions to connect diametral sides of the mirror  121  to an upper distal end of the hollow pipe  142  to rotate the mirror in response to the rotation of the hollow pipe  142 . The upper distal end of the hollow pipe  142  and the mirror support  122  are connected by the base plate  123 . Meanwhile, the vertical driving link  124  serves to connect the mirror  121  to the link base  134  to change the inclination of the mirror in response to the vertical movement of the link base. 
         [0036]    As noted above, the vertical driving link  124  is vertically moved in response to the vertical movement of the link base, where a hinged connector  124   b  may be moved to change the inclination of the mirror. 
         [0037]    Therefore, the vertical driving link  124  may include a vertical axle  124   a  vertically connected to the link base and the connector axle  124   b  connected to a distal end of the vertical axle via a hinge, where the other distal end of the connector axle  124   b  is connected to a rear coupling body  125  of the mirror. 
         [0038]    The vertical axle  124   a  and the connector axle  124   b  are connected by a hinge  124   c  of spherical plane to change the inclination of the mirror  121  in response to the connector axle  124   b  being moved along the hinge by the vertical movement of the vertical axle  124   a.    
         [0039]    At this time, the connector axle  124   b  connected the mirror may be changed in length thereof when the inclination of the mirror is changed, whereby displacement of the horizontal direction of the mirror may be hindered. 
         [0040]    In order to solve the problem, the mirror  121  and the vertical driving link  124  are operated in such a manner that the other distal end of the connector axle inserted for constantly maintaining the length of the connector axle according to the changed inclination of the mirror is made to change in response to the inclination of the mirror. The rear coupling body  125  is connected in the same way as that of a linear ball bush. In order to absorb the inclination of the mirror, a distal end of the connector axle is connected to the linear ball bush mounted at the mirror. 
         [0041]    For example, as shown in  FIG. 5(   a ), in case that the mirror is inclined to 45°, the connector axle is deeply inserted into the linear ball bush, and in case the mirror is inclined to less than 45°, as shown in  FIG. 5(   b ), it can be noted that the connector axle is inserted by being pushed outside of the linear ball bush as compared in the mirror being inclined to 45°. 
         [0042]      FIG. 6  is a graphic illustrating a changed shape of an inclination of a mirror according to an exemplary embodiment of the present invention, where it can be noted that the screw is vertically rotated along the screw thread in response to the rotation of the vertical driving motor, and there is a change of inclination on the part of the mirror as the vertical driving link connected to an outer periphery of the screw is vertically moved. 
         [0043]    That is, in a case that the screw is centrally located, the mirror maintains a constant inclination (e.g., 45°), as shown in  FIG. 6(   b ), but the mirror  121  has a steep inclination (e.g., 60°), as shown in  FIG. 6(   a ) in a case where the vertical driving link moves down. Alternatively, in a case where the screw moves upwards to move the vertical driving link connected thereto upwards, the mirror  121  has a smaller inclination (e.g., 30°), as shown in  FIG. 6(   c ). 
         [0044]    There is an industrial applicability in the 3D laser range finder sensor according to the exemplary embodiments of the present invention in that the mirror can perform a 360°-rotation and simultaneously can adjust an inclination of the mirror differently to measure a 3D distance. 
         [0045]    There is an advantageous effect in the exemplary embodiments of the present invention in that a structure is provided that is capable of recognizing a vertical distance through horizontal rotation and inclination adjustment to enable the vertical and horizontal 3D spatial recognition. 
         [0046]    The above description of the disclosed embodiments is provided to enable any person of ordinary skill in the art to make or use the disclosure. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.