Abstract:
In order to reduce the calculation in robotic arm allocation, the invention provides a spherical linkage type surgical robotic arm, which includes a first curved bar having a first axis center and a second axis center, a second curved bar being equal to the first curved bar in length and having a third axis center and a fourth axis center, the third axis center in coincidence with the first axis center, a third curved bar having a fifth axis center and a sixth axis center and being pivoted to the second curved bar, and a fourth curved bar having a seventh axis center and an eighth axis center and being pivoted to the third curved bar and the first curved bar, thereby reducing the calculation burden and facilitating control and allocation.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Divisional of co-pending application Ser. No. 13/923,670, filed on 21 Jun. 2013, for which priority is claimed under 35 U.S.C. §120; and the entire contents of all of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to robots and more particularly, to a spherical linkage type surgical robotic arm. 
         [0004]    2. Description of the Related Art 
         [0005]    With the advances in medical technology, new surgical techniques have been continuously introduced. Fast and low risk surgical techniques that enable patients to recover faster have been the goal of the medical profession, and the very popular minimally invasive surgery in recent years is one of them. For example, endoscopic imaging technology and micro-surgical instruments are used in laparoscopic surgery, so that the surgery can be performed without making a large wound on the body of the patient, not only reducing blood loss in the patient but also enabling the body of the patient to recover quickly from the wound. 
         [0006]    However, when performing a laparoscopic surgery, the surgeon needs to insert an endoscopic imaging module and a surgical instrument module into the body of the patient and then to perform the surgery while simultaneously viewing the endoscopic image. Thus, the surgeon will need the assist of a mechanical arm to hold or operate the related surgical instruments so that the surgeon can proceed with the operation. 
         [0007]    Conventional robotic arms commonly have a complicated structure and require complicated calculations and precise control to achieve precise allocation. US 2007/0173976 A1 discloses a center robotic arm with five-bar spherical linkage for endoscopic camera. According to this design, each link has a different length (see  FIG. 7A  and  FIG. 7B ), therefore, it requires a large amount of calculations to precisely move the outward axis to the desired location. 
         [0008]    Further, US2012/0184968 discloses a robotic arm with five-bar spherical linkage, which uses a parallel spherical five-bar linkage. According to this design, the surgical instrument is affixed to an extension portion of one link (see  FIG. 15 ). This designs allows the surgical instrument to pass through the center of spherical rotation, however the other part beyond the center of spherical rotation will be turned with the respective link around the center of spherical rotation. During movement of the link, the large turning angle of the surgical instrument will reduce the readability for the surgeon to read the data being displayed on the surface of the surgical instrument. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a spherical linkage type surgical robotic arm, which reduces calculation burden by uniformizing link length, achieving better robotic arm control and allocation than conventional robotic arm designs. 
         [0010]    It is another object of the present invention to provide a spherical linkage type surgical robotic arm, which has an added instrument bar that provides a turn proportional relationship relative to the links so that the turning angle of the surgical instrument mounted at the instrument bar can be reduced, bringing to the surgeon better readability of the data being displayed on surface of the surgical instrument than conventional mechanical arm designs. 
         [0011]    To achieve these and other objects of the present invention, a spherical linkage type surgical robotic arm turnable around a center of spherical rotation in accordance with the present invention comprises a first curved bar, which comprises a first axis center and a second axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation; a second curved bar, which is equal to the first curved bar in length, comprising a third axis center and a fourth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the third axis center coincides with the first axis center; a third curved bar, which comprises a fifth axis center and a sixth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the third curved bar being pivotally connected to the second curved bar in such a manner that the fifth axis center coincides with the fourth axis center; and a fourth curved bar, which comprises a seventh axis center and an eighth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the fourth curved bar being respectively pivotally connected to the third curved bar and the first curved bar in such a manner that the seventh axis center coincides with the sixth axis center and the eighth axis center coincides with the second axis center. 
         [0012]    Subject to the design that the first curved bar and the second curved bar have the same length, the calculation conditions are simplified, and therefore the calculation burden can be reduced, achieving easier robotic arm control and allocation than conventional robotic arm designs. 
         [0013]    Further, the invention also provides a spherical linkage type surgical robotic arm turnable around a center of spherical rotation, comprising a first curved bar, which comprises a first axis center and a second axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation; a second curved bar, which comprises a third axis center and a fourth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the third axis center coincides with the first axis center; a third curved bar, which comprises a fifth axis center and a sixth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the third curved bar being pivotally connected to the second curved bar in such a manner that the fifth axis center coincides with the fourth axis center; a fourth curved bar, which comprises a seventh axis center and an eighth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the fourth curved bar being respectively pivotally connected to the third curved bar and the first curved bar in such a manner that the seventh axis center coincides with the sixth axis center and the eighth axis center coincides with the second axis center; an instrument bar, which comprises an operational axis center passed through the center of spherical rotation, the instrument bar being pivotally connected to the third curved bar or the fourth curved bar such that the operational axis center coincides with the sixth axis center or the seventh axis center; a first proportional wheel fixedly mounted at the first curved bar to let the second axis center pass through the wheel axle center of the first proportional wheel; a second proportional wheel having a diameter larger than the diameter of the first proportional wheel, the second proportional wheel being fixedly mounted at the instrument bar to let the operational axis center pass through the wheel axle center of the second proportional wheel; and a flexible element wound round the first proportional wheel and the second proportional wheel. 
         [0014]    Subject to the arrangement of the instrument bar for the mounting of a surgical instrument and the arrangement of the first proportional wheel and the second proportional wheel, there is a turn proportional relationship between the instrument bar and the other curved bars so that the turning angle of the surgical instrument at the instrument bar can be reduced, bringing to the surgeon better readability of the data being displayed on the surface of the surgical instrument than conventional mechanical arm designs. 
         [0015]    Based on the same spirit of the invention, the invention also provides a spherical linkage type surgical robotic arm turnable around a center of spherical rotation, comprising: a first curved bar, which comprises a first axis center and a second axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation; a second curved bar, which comprises a third axis center and a fourth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation; a third curved bar, which comprises a fifth axis center and a sixth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the third curved bar being pivotally connected to the second curved bar in such a manner that the fifth axis center coincides with the fourth axis center; a fourth curved bar, which comprises a seventh axis center and an eighth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the fourth curved bar being respectively pivotally connected to the third curved bar and the first curved bar in such a manner that the seventh axis center coincides with the sixth axis center and the eighth axis center coincides with the second axis center; a ground bar, which comprises a ninth axis center and a tenth axis center respectively located at two opposite ends thereof and passed through the center of spherical rotation, the ninth axis center coincides with the first axis center and the tenth axis center coincides with the third axis center; an instrument bar, which comprises an operational axis center passed through the center of spherical rotation, the instrument bar being pivotally connected to the third curved bar or the fourth curved bar such that the operational axis center coincides with the sixth axis center or the seventh axis center; a first proportional wheel fixedly mounted at the first curved bar to let the second axis center pass through the wheel axle center of the first proportional wheel; a second proportional wheel having a diameter larger than the diameter of the first proportional wheel, the second proportional wheel being fixedly mounted at the instrument bar to let the operational axis center pass through the wheel axle center of the second proportional wheel; and a flexible element wound round the first proportional wheel and the second proportional wheel. 
         [0016]    Subject to the arrangement of the instrument bar for the mounting of a surgical instrument and the arrangement of the first proportional wheel and the second proportional wheel, there is a turn proportional relationship between the instrument bar and the other curved bars so that the turning angle of the surgical instrument at the instrument bar can be reduced, bringing to the surgeon better readability of the data being displayed on the surface of the surgical instrument than conventional mechanical arm designs. 
         [0017]    Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is an elevational view of a spherical linkage type surgical robotic arm in accordance with a first embodiment of the present invention. 
           [0019]      FIG. 2  is an elevational view of the spherical linkage type surgical robotic arm in accordance with the first embodiment of the present invention when viewed from another angle. 
           [0020]      FIG. 3  is a side view of the spherical linkage type surgical robotic arm in accordance with the first embodiment of the present invention. 
           [0021]      FIG. 4  is an elevational view of a spherical linkage type surgical robotic arm in accordance with a second embodiment of the present invention. 
           [0022]      FIG. 5  is a side view of the spherical linkage type surgical robotic arm in accordance with the second embodiment of the present invention. 
           [0023]      FIG. 6  is a bottom view of the spherical linkage type surgical robotic arm in accordance with the second embodiment of the present invention. 
           [0024]      FIG. 7  is a schematic perspective view of a spherical linkage type surgical robotic arm in accordance with a third embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Referring to  FIGS. 1-3 , a spherical linkage type surgical robotic arm in accordance with a first embodiment of the present invention is shown turnable around a center of spherical rotation C. The spherical linkage type surgical robotic arm comprises a first curved bar  11 , a second curved bar  12 , a third curved bar  13  and a fourth curved bar  14 . 
         [0026]    It is to be noted that the axle center described in this specification is a virtual axis about which an object is turned. 
         [0027]    The first curved bar  11  has a first axis center  11   a  and a second axis center  11   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. 
         [0028]    The second curved bar  12  is of equal length relative to the first curved bar  11 , having a third axis center  12   a  and a fourth axis center  12   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. Further, the third axis center  12   a  coincides with the first axis center  11   a.    
         [0029]    The third curved bar  13  has a fifth axis center  13   a  and a sixth axis center  13   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. The third curved bar  13  is pivotally connected to the second curved bar  12 . Further, the fifth axis center  13   a  coincides with the fourth axis center  12   b.    
         [0030]    The fourth curved bar  14  has a seventh axis center  14   a  and an eighth axis center  14   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. The fourth curved bar  14  is respectively pivotally connected to the third curved bar  13  and the first curved bar  11 . The seventh axis center  14   a  coincides with the sixth axis center  13   b.  The eighth axis center  14   b  coincides with the second axis center  11   b.    
         [0031]    In addition to the condition that the first curved bar  11  and the second curved bar  12  have the same length, the third curved bar  13  and the fourth curved bar  14  can be made having the same length, simplifying the program operation in controlling the motion of every curved bar in the preferred embodiments of the present invention. More particularly, the second curved bar  12  and the third curved bar  13  can be made having the same length. In this embodiment, the first curved bar  11 , the second curved bar  12 , the third curved bar  13  and the fourth curved bar  14  have the same length, further reducing the calculation burden and shortening the calculation time. 
         [0032]    In this embodiment, the spherical linkage type surgical robotic arm further comprises a first driving mechanism  15  and a second driving mechanism  16 . The first driving mechanism  15  is a combination of a motor and a speed reducer for driving an object to rotate, comprising a first driving shaft  151  connected to the first curved bar  11  and coincided with the first axis center  11   a.  The second driving mechanism  16  comprises a second driving shaft  161  connected to the second curved bar  12  and coincided with the third axis center  12   a.  Because the first driving shaft  151  and the second driving shaft  161  are respectively and directly connected to the first curved bar  11  and the second curved bar  12 , the number of component parts can be relatively reduced, thereby reducing the manufacturing cost and shortening the assembling time, and therefore the invention is cost-effective. Further, through the first driving mechanism  15  and the second driving mechanism  16  to control relative motion between the first curved bar  11  and the second curved bar  12 , the motion of the spherical linkage type surgical robotic arm is thus controlled. 
         [0033]    It is to be noted that the curved bar length indicated herein means the shortest distance between the two centers of axis of each curved bar at the common sphere based on the center of spherical rotation C. 
         [0034]    Referring to  FIGS. 4 and 5 , a spherical linkage type surgical robotic arm in accordance with a second embodiment of the present invention is shown. This second embodiment is substantially similar to the aforesaid first embodiment with the exception that this second embodiment further comprises an instrument bar  17 , a first proportional wheel  18 , a second proportional wheel  19 , and a flexible element  21 . 
         [0035]    The instrument bar  17  comprises an operational axis center  17   a  passed through the center of spherical rotation C. The instrument bar  17  is pivotally connected to the third curved bar  13  or fourth curved bar  14 . Further, the operational axis center  17   a  coincides with the sixth axis center  13   b  or seventh axis center  14   a.    
         [0036]    The first proportional wheel  18  is fixedly connected to the first curved bar  11  and rotatable with the first curved bar  11  to let the second axis center  11   b  pass through the wheel axle center of the first proportional wheel  18 . 
         [0037]    The diameter of the second proportional wheel  19  is larger than the diameter of the first proportional wheel  18 . Further, the second proportional wheel  19  is fixedly connected to the instrument bar  17  and rotatable with the instrument bar  17  to let the operational axis center  17   a  pass through the wheel axle center of the second proportional wheel  19 . 
         [0038]    The flexible element  21  is wound round the first proportional wheel  18  and the second proportional wheel  19 . In this embodiment, the flexible element  21  is a steel wire rope. However, this is not a limitation. It can also be a rope or belt. 
         [0039]    In this embodiment, installation of the first proportional wheel  18 , the second proportional wheel  19  and the flexible element  21  achieves the effect of enabling the turning angle of the instrument bar  17  to be smaller than the turning angle of the fourth curved bar  14  without the condition of having the first curved bar  11  and the second curved bar  12  to be made equal in length. However, if the first curved bar  11  and the second curved bar  12  have the same length, it achieves the effect of shortening the calculation time. Further, the second curved bar  12  and the third curved bar  13  can also be made equal in length, enhancing the effects. 
         [0040]    If the diameter of the second proportional wheel  19  is twice the diameter of the first proportional wheel  18  under the condition that the first curved bar  11 , the second curved bar  12 , the third curved bar  13  and the fourth curved bar  14  have the same length, the contained angle between the instrument bar  17  and the third curved bar  13  and the contained angle between the instrument bar  17  and the fourth curved bar  14  can be kept equal. 
         [0041]    During the operation of the second embodiment of the present invention, due to the installation of the first proportional wheel  18  and the second proportional wheel  19 , there is a turn proportional relationship between the instrument bar  17  and the first curved bar  11 , and therefore the turning angle of the surgical instrument mounted at the instrument bar  17  can be reduced, bringing to the surgeon better readability of the data being displayed on the surface of the surgical instrument than conventional mechanical arm designs. 
         [0042]    Referring to  FIG. 7 , a spherical linkage type surgical robotic arm in accordance with a third embodiment of the present invention is shown turnable about a center of spherical rotation. The spherical linkage type surgical robotic arm comprises: a first curved bar  31 , a second curved bar  32 , a third curved bar  33 , a fourth curved bar  34 , a ground bar  35 , an instrument bar  36 , a first proportional wheel  37 , a second proportional wheel  38  and a flexible element  39 . 
         [0043]    The first curved bar  31  has a first axis center  31   a  and a second axis center  31   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. 
         [0044]    The second curved bar  32  has a third axis center  32   a  and a fourth axis center  32   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. 
         [0045]    The third curved bar  33  has a fifth axis center  33   a  and a sixth axis center  33   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. The third curved bar  33  is pivotally connected to the second curved bar  32 . Further, the fifth axis center  33   a  coincides with the fourth axis center  32   b.    
         [0046]    The fourth curved bar  34  has a seventh axis center  34   a  and an eighth axis center  34   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. The fourth curved bar  34  is respectively pivotally connected to the third curved bar  33  and the first curved bar  31 . The seventh axis center  34   a  coincides with the sixth axis center  33   b.  The eighth axis center  34   b  coincides with the second axis center  31   b.    
         [0047]    The ground bar  35  has a ninth axis center  35   a  and a tenth axis center  35   b  respectively located at two opposite ends thereof and passed through the center of spherical rotation C. Further, said ninth axis center  35   a  being coincided with said first axis center  31   a,  and the tenth axis center  35   b  coincides with the third axis center  32   b.    
         [0048]    The instrument bar  36  comprises an operational axis center  36   a  passed through the center of spherical rotation C. The instrument bar  36  is pivotally connected to the third curved bar  33  or fourth curved bar  34 . Further, the operational axis center  36   a  coincides with the sixth axis center  33   b  or seventh axis center  34   a.    
         [0049]    The first proportional wheel  37  is fixedly connected to the first curved bar  31  and rotatable with the first curved bar  31  to let the second axis center  31   b  pass through the wheel axle center of the first proportional wheel  37 . 
         [0050]    The diameter of the second proportional wheel  38  is larger than the diameter of the first proportional wheel  37 . Further, the second proportional wheel  38  is fixedly connected to the instrument bar  36  and rotatable with the instrument bar  36  to let the operational axis center  36   a  pass through the wheel axle center of the second proportional wheel  38 . 
         [0051]    The flexible element  39  is wound round the first proportional wheel  37  and the second proportional wheel  38 . In this embodiment, the flexible element  39  is a steel wire rope. However, this is not a limitation. It can also be a rope or belt. 
         [0052]    In this embodiment, in addition to the condition that the first curved bar  31  and the second curved bar  32  have the same length, the third curved bar  33  and the fourth curved bar  34  can also be made having the same length to simplify the calculation in controlling the motion of each curved bar. More particularly, the second curved bar  32  and the third curved bar  33  can be made having the same length. For example, in this embodiment, the first curved bar  31 , the second curved bar  32 , the third curved bar  33  and the fourth curved bar  34  have the same length, further reducing the calculation burden and shortening the calculation time. Further, due to the installation of the first proportional wheel  37  and the second proportional wheel  38 , there is a turn proportional relationship between the instrument bar  36  and the first curved bar  37 , and therefore the turning angle of the surgical instrument mounted at the instrument bar  36  can be reduced, bringing to the surgeon better readability of the data displayed on the surface of the surgical instrument when compared to conventional mechanical arm designs. 
         [0053]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.