Abstract:
An approach is disclosed for providing a humanoid joint for a robotic system. A joint apparatus includes a supporting part, a rotating part and a pair of joint part, wherein the supporting part and the rotating part are coupled in which the joint part is disposed, wherein a rotational force is initially driven by a joint part and the rotational force is transmitted to the other joint part using a sliding motion generated at an abutted surface of each joint part, wherein the surface is formed at the end of the joint part, wherein the transmitted rotational forces can be converted into a motion by the restriction of movement of joint part occurred within the limited space formed by the coupling of rotational part and supporting part.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the earlier filing date under 35 U.S.C. §119 of Korean Patent Application No. 2006-0069422 filed Jul. 25, 2006, entitled “Joint Apparatus and Hand Apparatus for Robot using the same”; the entirety of which is incorporated by reference. 
       FIELD OF THE INVENTION 
       [0002]    Embodiments of the invention relate to a robot, and more particularly, to provide humanoid joints associated with structure, joint and an actuator for improving performance of a robot capable of human-like sense or touch. 
       BACKGROUND OF THE INVENTION 
       [0003]    A humanoid robot is a robot with its overall appearance based on that of the human body. In general, humanoid robots have a torso with a head, arms, hands and legs. Some forms of humanoid robots may model only part of the body, for example, face, eyes, mouth and hands. 
         [0004]    These humanoid robots resemble a human body and are capable of performing a variety of complex human tasks on commands or by being programmed in advance. However, there exist difficulties in mechanically embodying such function of the human body, especially requiring structuring mechanism in order to embody the mechanism in body motions. 
         [0005]    As an example, the humanoid robot hand has a plurality of finger mechanisms (e.g., a thumb, an index finger, a middle finger, a ring finger and a little finger) extended from distal ends of a main body, and each finger mechanism is provided with a plurality of joint portions and a plurality of link members which are respectively disposed between the joint and connected portions in order. 
         [0006]    A number of techniques have been developed to propose a robot hands as mimic a functionality of human hand. To achieve this, actuators for driving joint portions of each finger mechanism are provided at a place corresponding to the each finger mechanism. As such, it is required that each of the joint portions is driven by using the actuator directly or through a wire associated with a pulley on which the wires are wound. Some of these traditional approaches for configuring such hand mechanism are fully disclosed in Japanese Patent Laid-Open Publication Nos. sho 60-207795 and Hei 6-8178. 
         [0007]    However, these conventional techniques suffer from many drawbacks. For example, in a conventional hand apparatus having a plurality of fingers that require plurality of actuators that are provided at every finger mechanism. As such, even though expanding and contracting action of each finger mechanism can be controlled independently, there exist disadvantages that require separate spaces associated with members for embodying this approach. Consequently, the approach does not permit practical way—it may require complicated structure and significant time to deploy the apparatus. 
         [0008]    Furthermore, separate wires for connecting the finger mechanism and actuators corresponding to each movable point can be a burden. For example, spaces through which the wire is passed for electrical connection to actuate the robotic hands that are needed at each joint mechanism for a finger. It is evident that all of these requirements make the structure more complicated. 
       SUMMARY OF THE INVENTION 
       [0009]    These and other needs are addressed by the invention, in which an approach is presented for accounting for the types of applications as to effectively accommodate for a humanoid joint for a robotic system. 
         [0010]    According to one aspect of an embodiment of the invention, a joint apparatus includes a supporting part; and a rotating part configured to be rotated by a rotational force transmitted to the supporting part, wherein the rotating part is coupled to the supporting part; and a joint part configured to convert the rotational force into a rotational motion using a sliding force that is generated at abutted surfaces formed at the end of the joint part in contact, wherein a first joint part resides within the rotating part and a second joint part resides within the supporting part. 
         [0011]    According to another aspect of an embodiment of the invention, a hand apparatus for a robot is disclosed. The hand apparatus includes a wrist part; a plurality of finger parts disposed in parallel to the wrist part having a plurality of link members; a joint part disposed between the link members the joint part configured to convert a rotational force generated by a first joint part into a rotational motion of a second joint part, wherein the rotational force is converted into a hand motion occurred at contact surfaces of the each joint part abutted each other; and a thumb part formed at the wrist part configured to be rotated. 
         [0012]    According to another aspect of an embodiment of the invention, an apparatus for providing humanoid robot hands is disclosed. A plurality of joint members being coupled within a plurality of structures means for configuring a humanoid robotic hand, wherein the each joint member is a pair and each pair has a symmetrical shape at end; means for disposing the pair within the structure and the each structure is hinged each other, wherein a space is formed at hinged part; and means for providing a rotational force to a joint member, wherein the provided rotational force can be converted to a rotational motion through a sliding force occurred at the contact formed by the symmetrical shape of the each pair abutted against each other, wherein the rotational motion is converted into hand motion by the rotational motion is restricted within the space, wherein a desired motion for the humanoid robot hand can be achieved. 
         [0013]    According to yet another aspect of an embodiment of the invention, a method for providing a humanoid joint for a robotic system is provided. The method includes configuring a plurality of elements for embodying the humanoid robotic system, wherein the elements can include a supporting part, a motion part and a joint part; forming a first contact at a hemispherical shape at the end of one joint part; forming a second contact at a hemispherical shape at the end of the other joint, wherein the joint part is a pair; disposing the joint part within the supporting part and the motion part respectively, wherein the supporting part and the motion part are hinged; providing a power to a joint part having the first contact for generating a rotational force, wherein the rotational force is transmitted to the second contact abutted at the first contact at which a sliding force is occurred, wherein the sliding force causes the second contact to move, wherein the movements of the contact are restricted within the space formed at the hinged portion, wherein various motions can be achieved for the humanoid joint. 
         [0014]    Still other aspects, features, and advantages of the embodiments of the invention are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the embodiments of the invention. The invention is also capable of other and different embodiments, and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
           [0016]      FIG. 1A  is a perspective view of a joint apparatus in accordance with an embodiment of the invention; 
           [0017]      FIG. 2  is an exploded perspective view of the joint apparatus in accordance with an embodiment of the invention; 
           [0018]      FIG. 3  is a cross-sectional view of the joint apparatus in accordance with an embodiment of the invention; 
           [0019]      FIG. 4  is a perspective view of a hand apparatus for a robot using the joint apparatus in accordance with an embodiment of the invention; 
           [0020]      FIG. 5  is a lower perspective view of the hand apparatus for the robot using the joint apparatus in accordance with an embodiment of the invention; 
           [0021]      FIG. 6  is an enlarged perspective view of the hand apparatus for the robot using the joint apparatus in accordance with an embodiment of the invention; and 
           [0022]      FIG. 7  is a partially cut-away perspective view showing an internal structure of an index finger part of the hand apparatus for the robot using the joint apparatus in accordance with an embodiment of the invention; 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    A device, and method for providing humanoid joint for a robotic system are described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It is apparent, however, to one skilled in the art that the embodiments of the invention may be practiced without these specific details or with an equivalent arrangement. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the embodiments of the invention. 
         [0024]    Although the embodiments of the invention are discussed with respect to a humanoid robotic hand, it is recognized by one of ordinary skill in the art that the embodiments of the inventions have applicability to any type of robotic system as well any mechanism. 
         [0025]    As shown in  FIGS. 1 to 3 , a joint apparatus  100  of the present invention includes a supporting unit  110  and a rotating unit  120  which are respectively formed into an external frame and rotatably coupled with each other, a joint unit  130  which is provided at an inside of the supporting unit  110  and rotating unit  120  so that the rotating unit  120  is rotated by a sliding frictional motion generated when power is transmitted to the supporting unit  110 , and a power unit (not shown) for providing a rotational torque to the joint unit  130 . 
         [0026]    In this example, the supporting unit  110  and the rotating unit  120  are separated by an operational state. Therefore, the roles of the supporting unit  110  and the rotating unit  120  may be exchanged according to the operational state. 
         [0027]    The supporting unit  110  and the rotating unit  120  are formed with an outer coupling part  112  and an inner coupling part  122  at their ends adjacent to each other so that the outer and inner coupling parts  112  and  122  are rotatably coupled with each other, and a space for receiving the joint unit  130  is formed between the outer and inner coupling parts  112  and  122 . A rotational center of each of the outer and inner coupling parts  112  and  122  is formed to be the same as that of the joint unit  130 . 
         [0028]    The joint part  130  is provided with a first joint  132   a  which is rotatably disposed at an inside of the supporting unit  110  in a length direction of the supporting unit  110 , and a second joint  132   b  which is rotatably disposed at an inside of the rotating unit  120  in a length direction of the rotating unit  120 . At each end of the first and second joints  132   a  and  132   b , there are respectively formed with first and second pressure hemispherical parts  134   a  and  134   b.    
         [0029]    By way of example, the first and second pressure hemispherical parts  134   a  and  134   b  are respectively formed with first and second contact surfaces  136   a  and  136   b  which have the same shape and by which the first and second pressure hemispherical parts  134   a  and  134   b  are closely contacted with each other. The first and second contact surfaces  136   a  and  136   b  are inclined at the same angle, respectively. First and second shaft holes  138   a  and  138   b  are respectively formed at center portions of the first and second contact surfaces  136   a  and  136   b  so that a rotational shaft  139  is inserted into the first and second shaft holes  138   a  and  138   b  so as to be rotated in a state that the first and second contact surfaces  136   a  and  136   b  are closely contacted with each other. 
         [0030]    The power unit is to provide a rotational force to the first joint  132   a  which is rotatably disposed in the supporting unit  110 . A brushless DC motor (BLDC) is used as the power unit. Also, a reduction gear (not shown) for adjusting a rotational ratio, an encoder (not shown) for detecting a rotational level and the like may be further provided. 
         [0031]    As an exemplary embodiment, the operation of the joint apparatus is described in detail. It is noted that each element to be described below shall be understood with reference to  FIGS. 1 to 3  and the above descriptions. 
         [0032]    In the joint apparatus  110  as described above, the power unit generates power to rotate the rotating part  120  coupled with the supporting part  110 . Therefore, the power generated from the power unit is transmitted to the first joint  132   a  disposed in the supporting unit  110  so as to rotate the first joint  132   a . By the rotation of the first joint  132   a , the power is transmitted from the first joint  132   a  to the second joint  132   b . As evident from the joint, the second joint  132   b  is also rotated. 
         [0033]    The first joint  132   a  and the second joint  132   b  are closely contacted with each other through the first and second contact surfaces  136   a  and  136   b  of the first and second pressure hemispherical parts  134   a  and  134   b . The first and second contact surfaces  136   a  and  136   b  are contacted and coupled with each other by a rotational shaft  139  in a state of being inclined at a desired angle with respect to a rotational center of the first and second joints  132   a  and  132   b.    
         [0034]    Therefore, if the rotational force of the first joint  132   a  is transmitted to the second joint  132   b , a sliding motion is occurred between the first and second contact surfaces  136   a  and  136   b  and thus the second joint  132   b  is rotated with the rotational shaft  139  in the center. 
         [0035]    However, since the first and second supporting units  132   a  and  132   b  are constrained by the outer and inner coupling parts  112  and  122  of the supporting unit  110  and the rotating unit  120 , the rotating unit  120  is rotated with respect to the supporting unit  110  in a state that the rotational motion of the second joint  132   b  is limited to a direction that the rotating unit  120  can be rotated. Therefore, the rotational force of the power unit can be converted into the rotational motion of the rotating unit  120  with respect to the supporting unit  110 . 
         [0036]    The hand apparatus for the robot using the joint apparatus according to an embodiment of the invention has a similar shape to a human hand. That is, like the human hand, the hand apparatus is provided with a thumb, an index finger, a middle finger, a ring finger and a little finger. However, if necessary, the number of fingers of the hand apparatus may be changed. 
         [0037]    Further, the number of link members and joints forming each finger in the hand apparatus may be the same as that of the human hand. However, if necessary, it may be also changed. 
         [0038]    Furthermore, the structure of the link member and joint applies the joint apparatus. Now, a structure and operation of the joint will be described with reference to the drawings. 
         [0039]    As shown in  FIGS. 4 and 5 , the hand apparatus  200  using the joint apparatus according to an embodiment of the invention includes a wrist part  210  which is rotatably disposed at an arm part (not shown) of the robot (not shown) and a plurality of finger parts (a thumb part  220 , a index finger part  230 , a middle finger part  240 , a ring finger part  250  and a little finger part  260 ) extended from the wrist part  210 . 
         [0040]    The thumb part  220  is rotatably disposed at an outside of the wrist part  210 , which is adjacent to a side of the index finger part  230 . That is, the thumb part  220  can be rotated to a lower side of the index finger part  230  from the side of the index finger part  230 . 
         [0041]    The thumb part  220  includes a supporting link  226  for rotatably supporting the thumb part  220  with respect to the wrist part  210 , and a rotating link  224  of which one end is rotated by a rotating motor  226   a  and the other end is coupled with a desired part of the thumb part  220 . 
         [0042]    If the rotating link  224  is rotated by the rotating motor  226   a , the thumb part  220  coupled with the other end of the rotating link  224  is rotated, and the thumb part  220  is rotated to the lower side of the index finger part  230  while being supported by the rotating link  224 . The rotating motor  226   a  may be further provided with an encoder  226   b  for detecting the rotation of the rotating motor  226   a , and a reduction gear  226   c  for adjusting the rotational ratio of the rotating motor  226   a.    
         [0043]    The index finger part  230 , the middle finger part  240  and the ring finger part  250  are extended from a center portion of the wrist part  210  in one direction with the middle finger part  240  in the center. The index finger part  230  and the ring finger part  250  disposed at both sides of the middle finger part  240  are disposed to be rotated in a horizontal direction with respect to the extended direction of each finger part  230 ,  240 ,  250 ,  260 . 
         [0044]    Further, each of index finger part  230 , the middle finger part  240 , the ring finger part  250  and the little finger part  260  is provided with a plurality of link members  232   a ,  232   b ,  232   c  and  232   d , and a plurality of joints  234   a ,  234   b ,  234   c  and  234   d  interposed between adjacent link members. Preferably, each finger part  220 ,  230 ,  240 ,  250  and  260  has a similar structure to the human hand. 
         [0045]    In this example, since the index finger part  230 , the middle finger part  240 , the ring finger part  250  and the little finger part  260  have the same structure and shape except the directions of the link members and the joints which form each finger part, only the index finger part will be described and the description for the other finger part will be omitted. 
         [0046]    As shown in  FIGS. 6 and 7 , the index finger part  230  of the hand apparatus  200  for the robot, according to an embodiment of the invention, is coupled with the wrist part  210  so as to be rotated horizontally, and includes a first link member  232   a  forming a palm portion of the hand apparatus  200 , a second link member  232   b  coupled with the first link member  232   a  to be rotated vertically, a third link member  232   c  coupled with the second link member  232   b  to be rotated vertically, a fourth link member  233   d  coupled with the third link member  232   c  to be rotated vertically. 
         [0047]    A horizontal hinge part  212  is formed at the wrist part  210  so that the first link member  232   a  can be rotated horizontally with respect to the palm portion formed by the finger parts. A horizontal rotating part  236   a  coupled with the horizontal hinge part  212  is formed at an end of the first link member  232   a . Further, at a lower side of the horizontal hinge part  212  and the horizontal rotating part  236   a , there is provided a first joint part  234   a  of which one side is coupled with the wrist part  210  and the other side is coupled with the first link member  232   a.    
         [0048]    A first vertical rotating part  236   b  is provided between the first link member  232   a  and the second link member  232   b  so that the second link member  232   b  is supported to be rotated vertically with respect to the first link member  232   a . A second joint part  234   b  is provided at an inside of the first vertical rotating part  236   b  so as to be rotated the second link member  232   b  with respect to the first link member  232   a.    
         [0049]    In addition, a second vertical rotating part  236   c  is provided between the second link member  232   b  and the third link member  232   c  so that the third link member  232   c  is supported to be rotated vertically with respect to the second link member  232   b . A third joint part  234   c  is provided at an inside of the second vertical rotating part  236   c  so as to be rotated the third link member  232   c  with respect to the second link member  232   b.    
         [0050]    Finally, a third vertical rotating part  236   d  is provided between the third link member  232   c  and the fourth link member  232   d  so that the fourth link member  232   d  is supported to be rotated vertically with respect to the third link member  232   c . A forth joint part  234   d  is provided at an inside of the third vertical rotating part  236   d  so as to be rotated the fourth link member  232   d  with respect to the third link member  232   c.    
         [0051]    As an exemplary embodiment, the first, second and third vertical rotating part  236   b ,  236   c  and  236   d  have respectively the same structure as the outer and inner coupling parts  112  and  122  of the joint apparatus  100  according to an embodiment of the invention. 
         [0052]    Meanwhile, the second, third and fourth joint parts  234   b ,  234   c  and  234   d  as described above are mounted in a direction orthogonal to the mounting direction of the first joint part  234   a . That is, when the joint parts  234   a ,  234   b ,  234   c  and  234   d  are respectively operated at their initial positions, the second, third and fourth joint parts  234   b ,  234   c  and  234   d  are operated in a direction orthogonal to an operation direction of the first joint part  234   a.    
         [0053]    In this example, the first, second, third and fourth joint parts  234   a ,  234   b ,  234   c  and  234   d  apply the joint apparatus  100  (referring to  FIG. 1 ) according to an embodiment of the invention. The joint parts  234   a ,  234   b ,  234   c  and  234   d  are respectively provided with first joints  234   a   1 ,  234   b   1 ,  234   c   1  and  234   d   1  and second joints  234   a   2 ,  234   b   2 ,  234   c   2  and  234   d   2 . Each of the first joints  234   a   1 ,  234   b   1 ,  234   c   1  and  234   d   1  has a separate power unit  235   a ,  235   b ,  235   c  and  235   d.    
         [0054]    At each end of the first joints  234   a   1 ,  234   b   1 ,  234   c   1  and  234   d   1  and second joints  234   a   2 ,  234   b   2 ,  234   c   2  and  234   d   2  which are adjacent to each other, there is formed a pressure hemispherical part having an inclined contact surface at a desired angle. The contact surface formed at the pressure hemispherical part is restricted to be rotated around a rotational axis orthogonal to the contact surface. When the rotational force is generated at the first joints  234   a   1 ,  234   b   1 ,  234   c   1  and  234   d   1 , the rotational force is transmitted from the first joints  234   a   1 ,  234   b   1 ,  234   c   1  and  234   d   1  to the second joints  234   a   2 ,  234   b   2 ,  234   c   2  by the sliding motion between the contact surfaces so that the second joints  234   a   2 ,  234   b   2 ,  234   c   2  are rotated. The first joints  234   a   1 ,  234   b   1 ,  234   c   1  and  234   d   1  and the second joints  234   a   2 ,  234   b   2 ,  234   c   2  and  234   d   2  shall be understood with reference to the description of the first joint  132   a  and the second joint  132   b  of the joint apparatus. 
         [0055]    By way of example, the each of the power units  235   a ,  235   b ,  235   c  and  235   d  includes a motor for generating the rotational force, an encoder for detecting the rotational force of the motor, and a reduction gear for adjusting the rotational ratio of the motor. 
         [0056]    The power units  235   a ,  235   b ,  235   c  and  235   d  disposed in the first, second, third and fourth joint parts  234   a ,  234   b ,  234   c  and  234   d  may be operated independently or may be operated at the same time by applying a desired voltage. Further, the first, second, third and fourth joint parts  234   a ,  234   b ,  234   c  and  234   d  may be operated using the power supplied from one of the power units  235   a ,  235   b ,  235   c  and  235   d  by linking the power of the first, second, third and fourth joint parts  234   a ,  234   b ,  234   c  and  234   d  to each other. 
         [0057]    When the index finger part  230  disposed at the wrist part  210  is rotated horizontally, the power unit  235   a  of the first joint part  234   a  disposed at the lower side of the horizontal hinge part  212  of the wrist part  210  and the first link member  232   a  of the horizontal rotating part  236   a  is operated. Thus, the first joint  234   a   1  of the first joint part  234   a  is rotated by the power unit  235   a  and then the power is transmitted to the second joint  234   a   2 . 
         [0058]    Therefore, while the sliding motion is occurred between the contact surfaces of the pressure hemispherical parts formed at each end of the first and second joints  234   a   1  and  234   a   2 , the contact surfaces are rotated around the rotational shaft provided between the contact surfaces. Sequentially, while the second joint  234   a   2  is rotated with the rotational shaft in the center, the first link member  232   a  coupled with the second joint  234   a   2  is reciprocated horizontally. Thus, the first link member  232   a  is rotated horizontally by the horizontal rotating part  236   a  coupled with the horizontal hinge part  212  of the wrist part  210 . 
         [0059]    Now, the vertical rotating motion of the second and third and fourth link members  232   b ,  232   c  and  232   d  will be described. Herein, the vertical rotating motion of the second and third and fourth link members  232   b ,  232   c  and  232   d  is performed through the equivalent processes, and thus the operation of the second link member  232   b  is described and the description of the third and fourth link members  232   c  and  232   d  are the equivalent processes that are shown in  FIGS. 6-7  in order to avoid unnecessarily obscuring the embodiments of the invention. 
         [0060]    First of all, in order to rotate the second link member  232   b  couple with the first link member  232   a  to be rotated vertically, the power unit  235   b  of the second joint part  234   b  provided between the first and second link members  232   a  and  232   b  is operated. Thus, the first join  234   b   1  forming the second joint part  234   b  is rotated by the power unit  235   b  and the power is transmitted to the second joint  234   b   2 . 
         [0061]    Therefore, while the sliding motion is occurred between the contact surfaces of the pressure hemispherical parts formed at each end of the first and second joints  234   b   1  and  234   b   2 , the contact surfaces are rotated around the rotational shaft provided between the contact surfaces. Sequentially, while the second joint  234   b   2  is rotated with the rotational shaft in the center, the second link member  232   b  coupled with the second joint  234   b   2  is reciprocated vertically. 
         [0062]    In a way of example, the third and fourth link members  232   c  and  232   d  are also reciprocated through the same processes. Smooth finger motion can be obtained by controlling the third and fourth link members  232   c  and  232   d  independently. 
         [0063]    As described above, according to the joint apparatus of an embodiment of the invention, since each joint has a simple structure and can be operated independently, there is an advantage to provide the smooth finger motion. 
         [0064]    Further, according to the hand apparatus using the joint apparatus of an embodiment of the invention, there is another advantage to provide a hand apparatus which can be smoothly operated like a human hand by using the joint apparatus which has a simple structure and can be operated independently. 
         [0065]    While the invention has been described in connection with a number of embodiments and implementations, the invention is not so limited but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims. Although features of the invention are expressed in certain combinations among the claims, it is contemplated that these features can be arranged in any combination and order.