Abstract:
The invention concerns a device forming a robotic finger comprising a base ( 100 ) forming a palm, at least one knuckle ( 500, 700, 900 ) articulated on the base ( 100 ) about two separate joints ( 200, 400 ) non-parallel to each other, at least two actuators ( 110, 120, 130, 140 ) and cable-linking means ( 112, 122 ) respectively linking the two actuators ( 110, 120 ) to drive elements of said two joints ( 200, 400 ), characterised in that the device comprises guide means ( 150, 151, 152 ) designed to guide the cables involved in the control of each joint ( 400, 600, 800 ) located after the first joint ( 200 ) on the base ( 100 ), in a common plane passing through the axis ( 202 ) of said first joint ( 200 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to the field of robotic fingers. 
         [0002]    What is meant by “robotic finger” is an assembly of mechanical means, mutually hinged like the phalanges of a finger of a hand and controlled in displacement by actuators controlled by external means, such as automatic systems or processors. 
         [0003]    As will be seen below, within the scope of the present invention, different fingers can be combined to form a gripper or a robotic hand. 
       GOAL OF THE INVENTION 
       [0004]    The goal of the present invention is to improve the performance of known robotic hand devices, particularly with regard to grasping objects on the one hand, and the fine handling of objects at the fingertip on the other hand. 
         [0005]    One goal of the invention is in particular to propose means allowing identical kinematics to those of a human finger to be achieved. 
       PRIOR ART 
       [0006]    The creation of robotic fingers or hands has already led to a proliferation of literature on the subject. 
         [0007]    Examples will be found in the following documents:
   Grebenstein M., “Approaching human performance: the functionality driven Awiwi Robot Hand,” Diss. ETH N° 20471, 2012.   Iversen E. K., Khutti D. F., Johnson R. T., Biggers K. B., Jacobsen S. C., “Design of the UTAH/MIT dexterous hand,” in International Conference on Robotics and Automation, 1986, pp. 1520-1532.   Liu et Al., “Multisensory Five-Finger Dexterous Hand: The DLR/HIT Hand II,” IEEE/RSJ International Conference on Intelligent Robots and Systems, 2008.   S. Ueki, H. Kawasaki, T. Mouri, “Adaptive Coordinated Control of Multi-Fingered Robot Hand,” Journal of Robotics and Mechatronics, Vol. 21 No. 1, 2009.   Jun Ueda, Yutaka Ishida, Masahiro Kondo, Tsukasa Ogasawara, “Development of the NAIST-Hand with Vision-based Tactile Fingertip Sensor,” Proceedings of the 2005 IEEE International Conference on Robotics and Automation (ICRA 2005), pp. 2343-2348, 2005.   N. Daoud, J. P. Gazeau, S. Zeghloul, M. Arsicault, “A real-time strategy for dexterous manipulation: Fingertips motion planning, force sensing and grasp stability,” Journal of Robotics and Autonomous Systems, Vol. 60, March 2012, pp. 377-386.   J. P. Gazeau, S. Zeghloul, G. Ramirez, “Manipulation with a polyarticulated mechanical hand: a new efficient real-time method for computing fingertip forces for a global manipulation strategy,” Robotica, vol. 23, 2005, pp. 479-490.   D. Chaigneau, M. Arsicault, J. P. Gazeau, S. Zeghloul, “LMS robotic hand grasp and manipulation planning (an isomorphic skeleton approach)” Robotica (2008), vol. 26, 2008, pp. 177-188.   N. Daoud, J. P. Gazeau, S. Zeghloul, M. Arsicault, “A fast grasp synthesis method for online manipulation,” Journal of Robotics and Autonomous Systems, vol. 59, 2011, pp. 421-427.   F. Touvet, N. Daoud, J. P. Gazeau, S. Zeghloul, M. A. Maier, S. Eskiizmirliler, “A biomimetic reach and grasp approach for mechanical hand”, Journal of Robotics and Autonomous Systems, vol. 60, 2012, pp. 473-486.   
 
         [0018]    Without commenting in detail about all the solutions already proposed, two types of robotic hands frequently cited in the literature and generally designated “Shadow hand” and “AWIWI hand” will be mentioned below. 
       Shadow Hand 
       [0019]    The SHADOW hand is a robotic hand with an anthropomorphic design, the dimensions whereof are comparable to a human hand. It comprises actuators which can be pneumatic rams or electric motors depending on the embodiment. The hinges are actuated by cable transmission. The hand with its 5 fingers has 20 actuated degrees of freedom and 4 coupled degrees of freedom for a total of 24 hinges. The movement amplitudes are very close to the amplitudes of the human hand. 
         [0020]    Though having genuine advantages, the so-called Shadow hand has certain limitations. The mechanics of the hand do not allow fine control of the ends of the fingers in space. In fact the abduction-adduction movement is subject to nonlinearities (mechanical clearances, friction), which prevent producing precise movements of the fingers for handling objects on the ends of the fingers by using this movement (screwing in light bulbs for example). 
       AWIWI Hand or Hyper-Robust Hand 
       [0021]    The Robotics and Mechatronics Institute of the German Aerospace Center (DLR) has developed a hand capable of resisting collisions with rigid objects as well as hammer-blows without suffering any alteration of the mechanics of the hand. The robustness of the hand has been set as the core of the invention. The developed hand has anthropomorphic dimensions equipped with its 5 fingers. The latter include a total of 19 hinges with are actuated through 38 tendons each connected to an actuator. The control of the 38 actuators thus allows for constant control of the stiffness of the tendons and for absorbing considerable shocks. 
         [0022]    The essential drawback of this hand is the high degree of actuation, in that the design requires two actuators per hinge so as to control the stiffness of the finger. This makes it sizeable and heavy, with a bulky forearm. The considerable friction also impacts the capacity of the hand to produce fine movements at the fingertips. Thus, to date, it has been impossible to demonstrate the fine handling of objects with the fingertips of this hand. The proposed demonstrations demonstrate adaptive grasping capabilities and capabilities for numerous interactions in view of the hand&#39;s shock absorbent qualities. 
       DESCRIPTION OF THE INVENTION 
       [0023]    The invention relates to a device forming a robotic finger including a base forming a palm, at least one phalange hinged to the base around two independent hinges not parallel with one another, at least two actuators, cable-linking means connecting respectively the two actuators to driving elements of said two hinges, and guide means adapted for guiding the cables involved in the control of each hinge located after the first hinge on the base, in a common plane passing through the axis of this first hinge, characterized in that the guide means are formed from cylindrical needles extending along axes parallel to the first hinge axis, carried by the base, that the device comprises at least two needles at the output of a guide stage the separation whereof corresponds substantially, to the prerequisite operational clearance for ensuring free translation of the cables, to the diameter thereof, the two needles being positioned symmetrically on either side of a plane of symmetry passing through the first hinge axis and guiding the cables at the input of the first hinge, and that the device further comprises a frame which carries two series of diabolo-shaped parts symmetric with respect to the axis of the first hinge and intended to guide the cables coming from the guide stage formed by said needles, toward the downstream hinges. 
         [0024]    Preferably the first hinge axis on the base constitutes an abduction-adduction axis, while the second hinge axis constitutes a flexure-extension axis. 
         [0025]    The feature mentioned above, according to which the cables involved in the control of each hinge located after the first hinge on the base, are guided in a common plane passing through the first hinge axis, makes it possible to not modify the extension of these cables between the actuator and the corresponding hinge regardless of the position of the first hinge, and also allows friction to be minimized. This makes it possible to maximize the mechanical efficiency and to guarantee the ability to control the finger in force and in position. Moreover, the combination of this guiding of cables within a common plane at the input of the first hinge with the diabolo-shaped parts carried by the cable makes it possible to minimize the friction of the cables involved in the control of each hinge located after the first hinge, regardless of the pivoting amplitude of the first hinge. 
         [0026]    According to another advantageous feature of the present invention, the device comprises several phalanges, hinged to one another two by two around a single-axis hinge associated with a respective actuator. 
         [0027]    According to a particular embodiment, the device includes four hinges and three phalanges. The movements then proposed are three flexure-extension movements and one abduction-adduction movement. 
         [0028]    The transmission of movement between each hinge and the associated actuator is ensured by two transmission cables, which make it possible to ensure respectively a flexure or abduction movement and an extension or adduction movement. 
         [0029]    The dimensions of the finger can be adjusted depending on the target application. These dimensions can, as a minimum, correspond to the average dimensions of a human finger. 
         [0030]    The structure of the finger conforming to the invention makes it possible to install complete instrumentation for measuring force and position. 
         [0031]    Each hinge can integrate hinge measurement. 
         [0032]    The fingertip and the phalanges can accommodate force measurement. 
         [0033]    Personalized covering of the structure of the finger, for example in the shape of a shell and of a coating connected to the application, can be carried out using attachment elements. 
         [0034]    The modularity of each finger makes it possible to assemble several fingers to build a robotic hand with several fingers. The kinematics of the hand (placement of the fingers, number of fingers, dimensions of the fingers, particularly the length of the phalanges) can be adjusted depending on the target application. One can thus make the most complex robotic hand: an anthropomorphic hand in terms of kinematics and dimensions. 
       ADVANTAGES OF THE INVENTION 
       [0035]    The advantages of the device conforming to the invention comprising a transmission by cables are the following in particular: 
         [0036]    the actuators or motors can be deported outside the device, for example outside the hand, hence the possibility of reducing the size of the device and of the hand and their weight for on-board use; 
         [0037]    the actuators or motors can easily be dimensioned depending on the application. Dimensional constraints connected to the motors are nonexistent. If high torques are necessary, voluminous motors can be selected. They can for example be positioned at the shoulder of a manipulator arm, the useful lead whereof is naturally greater than for the end of an arm, via judicious routing of the transmission cables; 
         [0038]    the natural compliance induced by each cable at a finger offers reliable interaction with the environment by absorbing a portion of the energy connected with the impact; 
         [0039]    the elongation forces of a transmission cable can be used so as to evaluate the interaction between the finger and the environment. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0040]    Other features, goals and advantages of the present invention will appear upon reading the detailed description which follows, and with reference to the appended drawings, given by way of non-limiting examples and wherein: 
           [0041]      FIG. 1  shows in its  FIGS. 1 a  and 1 b    which correspond arbitrarily to a sagittal section plane and a cross section plane, different movement axes achievable by the finger conforming to the invention and an orthonormal coordinate system which will be referred to in the description hereafter, 
           [0042]      FIG. 2  shows a schematic of the hinged connections contained in a finger conforming to the invention, 
           [0043]      FIG. 3  illustrates a perspective view of an embodiment of a finger conforming to the invention, comprising 3 phalanges, 
           [0044]      FIG. 4  shows a view of the same finger according to a lateral view corresponding to a plane parallel to a sagittal plane, 
           [0045]      FIG. 5  shows a view of the same finger in a top view corresponding to a plane parallel to a transverse plane, 
           [0046]      FIG. 6  shows an enlarged partial view of  FIG. 5  and illustrates a first stage in cable guide means located in the base forming a palm, upstream of the first hinge, 
           [0047]      FIG. 7  shows an enlarged partial view of  FIG. 4  and illustrates a second stage of cable guide means located in the base forming a palm, between the first stage illustrated in  FIG. 6  and the first hinge, 
           [0048]      FIG. 8  details in a perspective view the position of cylindrical needles serving for guiding transmission cables to the input of the first hinge, 
           [0049]      FIG. 9  shows an end view in a frontal section plane, of the same needles, 
           [0050]      FIG. 10  shows a partial perspective view of the hinge assembly of the first phalange to the base, around two mutually non-parallel axes, corresponding to abduction-adduction and flexure-extension axes, 
           [0051]      FIG. 11  shows a partial detail view of this assembly and illustrates more precisely a half-shaft equipped with diabolos serving as guides for the cables, 
           [0052]      FIG. 12  shows a view of a cage supporting the aforementioned diabolos and a drive pulley, 
           [0053]      FIG. 13  shows a complete view of a hinge shaft corresponding to the first hinge axis on the base, 
           [0054]      FIG. 14  shows a second partial perspective view, at an observation angle opposite to  FIG. 10 , of the hinge assembly of the first phalange on the base, around two mutually non-parallel axes, corresponding to abduction-adduction and flexure-extension axes, 
           [0055]      FIG. 15  shows a perspective view of the complete hinge assembly of the first phalange on the base around two non-parallel axes, 
           [0056]      FIG. 16  shows a top view of the complete hinge assembly of the first phalange on the base, around two non-parallel axes, 
           [0057]      FIGS. 16   bis  and  16   ter  show two schematic section view of the first two hinges in two superimposed section planes, mutually parallel and orthogonal to the first hinge axis, 
           [0058]      FIG. 17  shows a partial perspective view of a hinge between two phalanges, and illustrates in particular receiver pulleys involved in driving and cable tension control devices, 
           [0059]      FIG. 18  shows a top view of a complete finger comprising three phalanges, 
           [0060]      FIG. 19  shows a lateral view in a sagittal plane of a hand with several fingers conforming to the invention, and 
           [0061]      FIG. 20  illustrates in perspective an embodiment of a hand with 4 fingers conforming to the invention, with the possibility of grasping. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0062]    The description which follows will be made with reference to an arbitrary coordinate system x y z wherein the plane x z corresponds to a vertical sagittal plane, the plane x y corresponds to a horizontal transverse plane and the plane y z corresponds to a vertical frontal plane. 
         [0063]    Shown schematically in  FIGS. 1   a,    1   b  and  2 , is a finger  10  comprising three phalanges  500 ,  700  and  900 : a first phalange  500  hinged to a base which will be designated  100  hereafter around a first hinge  200  defining a first abduction-adduction axis  202  and a second hinge  400  defining a second flexure-extension axis  402 , connected to the hinge  200  via an intermediate assembly  300 , the second, intermediate phalange  700  being hinged to the first phalange  500  by a hinge  600  defining a third flexure-extension axis  602  and the third, distal phalange  900  being hinged to the second phalange  700  by a hinge  800  defining a fourth flexure-extension axis  802 . 
         [0064]    The abduction-adduction axis  202  extends along a vertical axis z. 
         [0065]    The flexure-extension axes  402 ,  602  and  802  extend along mutually parallel horizontal axes y. 
         [0066]    At rest, in a generally aligned position, the 3 phalanges  500 ,  700  and  900  extend in an extension direction along x. 
         [0067]    The amplitude of the abduction or adduction displacement around the axis  202  is designated q 1  in  FIG. 1 b    with respect to an arbitrary median reference axis x. 
         [0068]    The respective amplitudes of flexure displacement around the respective axes  402 ,  602  and  802  of the three phalanges  500 ,  700  and  900  with respect to a rest position with rectilinear extension are designated q 2 , q 3  and q 4 . 
         [0069]    As previously indicated, an elementary robotic finger  10  conforming to the present invention comprises a base  100  forming a palm and at least one phalange  500  hinged to the base  100  around two independent, not mutually parallel hinge axes  202  and  402 . Preferably, the two axes  202  and  402  are mutually orthogonal. 
         [0070]    The finger  10  further comprises at least two actuators  110  and  120  and cable-linking means  112 ,  114  and  122 ,  124  respectively connecting the output of the actuator  110  to receiving drive pulleys  325 ,  326  provided in the assembly  300  for controlling the first hinge  200  and the output of the actuator  120  at the first phalange  500  for controlling the second hinge  400 . 
         [0071]    In the embodiment comprising 3 phalanges  500 ,  700  and  900 , the finger comprises 4 actuators  110 ,  120 ,  130  and  140 , each associated with two cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 . Each of the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  is connected respectively to a receiving drive pulley  325 ,  326  or an element, in this particular case pulleys  525 ,  526 ,  725 ,  726  and  925 ,  926 , phalanges  500 ,  700  and  900  for controlling a hinge axis  202 ,  402 ,  602  and  802 . 
         [0072]    Still more precisely according to the invention, the finger comprises guide means  150 ,  160  adapted for guiding the cables  122 ,  124 ;  132 ,  134  and  142 ,  144  involved in the control of each hinge  400 ,  600  and  800  located after the first hinge axis  202  on the base, in a common sagittal plane passing through this first hinge axis  202 . 
         [0073]    The base  100  can be subject to many embodiments. According to the embodiment shown in the appended figures, the base  100  comprises a housing  102  which carries the actuators  110 ,  120 ,  130  and  140  so that they have their respective output axis  111 ,  121 ,  131  and  141  rotatably mounted in the housing  102 , along an axis parallel to the axis z. 
         [0074]    The actuators  110 ,  120 ,  130  and  140  are preferably formed from gear motors. 
         [0075]    Each output axis  111 ,  121 ,  131  and  141  carries two axially stepped drive pulleys  113 ,  115 ,  123 ,  125 ,  133 ,  135 ,  143  and  145  on their respective axes. 
         [0076]    The housing  102  is extended on one side by a beam  104  which extends in a longitudinal direction centered on an extension axis along x. This extension axis of the beam  104  corresponds to a median symmetry plane of the beam which passes through all the rotation axes of the four actuators  110 ,  120 ,  130  and  140 . 
         [0077]    A first end of each cable  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  is attached to a respective pulley  113 ,  115 ,  123 ,  125 ,  133 ,  135 ,  143  and  145 . 
         [0078]    The pulleys  113 ,  115 ,  123 ,  125 ,  133 ,  135 ,  143  and  145  are located facing the beam  104 . 
         [0079]    The cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  run in the beam  104  from their respective pulley  113 ,  115 ,  123 ,  125 ,  133 ,  135 ,  143  and  145  in the direction of the first hinge  200 . 
         [0080]    As indicated previously, the beam  104  comprises two stages  150 ,  160  of guide means adapted for guiding the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 . 
         [0081]    The first stage  150  of guide means has the function of guiding at least the cables  122 ,  124 ;  132 ,  134  and  142 ,  144  involved in the control of each hinge  400 ,  600  and  800  located after the first hinge axis  202  on the base, in a common sagittal plane passing through the first hinge axis  202 . According to the embodiment shown in the figures, the guide means  150  are formed from cylindrical needles extending along axes parallel to the axis z carried by the beam  104 . 
         [0082]    Thus there is provided at least two main needles  151 ,  152  at the output of the first stage  150 , the separation whereof corresponds substantially to the prerequisite operational clearance for ensuring free translation of the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 , to the diameter thereof. The two main needles  151 ,  152  are positioned symmetrically on either side of the symmetry plane in xz of the beam  104  passing through the first hinge axis  202 . 
         [0083]    At the input to the stage  150 , the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 , are separated two by two by a distance corresponding to the summation of the respective radii of their respective pulley  113 ,  115 ,  123 ,  125 ,  133 ,  135 ,  143  and  145 . As can be seen in  FIG. 6 , the main needles  151 ,  152  make it possible to place all the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 , in the common plane passing through the axis  202 , at the output of the guide stage  150 . 
         [0084]    As can also be seen in  FIG. 6 , the device preferably further comprises three stages of auxiliary needles  153 ,  154 ;  155 ,  156  and  157 ,  158 , upstream of the main needles  151  and  152 , which respectively hold certain cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 , so as to ensure progressive convergence of pairs of cables between the main needles  151 ,  152 . 
         [0085]    The second stage  160  of guide means is placed between the first guide stage  150  and the first hinge  200 . It has the function of guiding and staging along the axis z the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  at the input of the hinge  200  so as to avoid any contact between these cables. More precisely, the guide means  160  also have the function of distributing the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  into two groups of 4, respectively upper and lower with reference to the axis z, as can be seen in  FIG. 7 . 
         [0086]    The upper group of 4 cables  112 ,  122 ,  132  and  142  is found in  FIG. 16   bis  and the lower group of 4 cables  114 ,  124 ,  134  and  144  in  FIG. 16   ter.    
         [0087]    According to the embodiment shown in the figures, the guide means  160  are formed from cylindrical needles extending along axes parallel to the axis y carried by the beam  104 . 
         [0088]    According to the preferred but non-limiting embodiment shown in  FIG. 7 , the device thus comprises 4 stages of auxiliary needles  162 ,  164 ,  166  and  168  which guide the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 , so as to ensure the expected positioning at the input of the hinge  200 . The multiplicity of stages  162 ,  164 ,  166  and  168  is intended to ensure progressive grouping of the cables into the two aforementioned groups without risk of contact between two cables. 
         [0089]    The precise configuration and the number of needles forming the guide stages  162 ,  164 ,  166  and  168  can be subject to numerous embodiments and will not be described in more detail hereafter. It will be noted, however, that in combination the 4 guide stages  162 ,  164 ,  166  and  168  have needles which serve as spacers between each pair of two adjoining cables at the output of the guide means  160  and needles which serve as a labyrinth for certain cables by successively providing an external support, then an internal support with reference to the z-height of the beam  104 , to certain cables. 
         [0090]    Preferably provided, moreover, at the output of the guide stage  160 , upstream of the hinge  200 , are two secondary needles  151   bis,    152   bis,  parallel to the aforementioned needles  151  and  152 , the separation whereof also corresponds substantially to the prerequisite operational clearance for ensuring free translation of the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 , to the diameter thereof, so as to guarantee good positioning of the cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  at the input to the hinge  200 . The two secondary needles  151   bis,    152   bis  are also positioned symmetrically on either side of the symmetry plane in xz of the beam  104  passing through the first hinge axis  202 . 
         [0091]    The structure of the two first hinges  200  and  400  will now be described, particularly with reference to  FIGS. 10 to 16 . 
         [0092]    As previously indicated, the first hinge  200  preferably corresponds to an abduction-adduction hinge around a z-axis  202 , while the second hinge  400  corresponds to a flexure-extension hinge around an y-axis  402 , i.e. not parallel to the axis  202  and preferably orthogonal to this axis  202 . The two hinges  200  and  400  are separated and carried by an intermediate assembly  300 . 
         [0093]    If need be, as a variant, the first hinge  200  could correspond to a flexure-extension hinge around an y-axis  202 , while the second hinge  400  could correspond to an abduction-adduction hinge around a z-axis  402 . 
         [0094]    According to the embodiment shown in the appended figures, the intermediate assembly  300  comprises a support frame  310  the median plane whereof extends, at rest, i.e in the centered position with respect to the extreme abduction and adduction positions, in a plane yz. The frame  310  carries respectively on its two opposite faces on either side of the median plane in yz, the abduction-adduction hinge  200  in z and the flexure-extension hinge  400  in y. 
         [0095]    More precisely, on a first face the frame  310  carries a small bridge  320  in the shape of a dihedral the median plane in thickness whereof extends in a xy-plane and which supports in rotation two coaxial abduction-adduction half-shafts or pins in z  220 ,  230  centered on the axis  202 . The pins  220 ,  230  are hinged to the base  100 , more precisely to the end of the beam  104 , by any appropriate means. 
         [0096]    The two half-shafts or pins  220 ,  230  are located respectively on either side of the small bridge  320 . One of the pins  220  carries a pulley  325  receiving the second end of the adduction cable  112 . The pulley  325  is connected in rotation with the small bridge  320  and the element  300  and is therefore free in rotation with respect to the pin  220 . The other half-pin  230  carries a pulley  326  receiving the second end of the abduction cable  114 . The pulley  326  is also connected in rotation with the small bridge  320  and the element  300  and is therefore free in rotation with respect to the pin  230 . 
         [0097]    The anchoring points of the cables  112  and  114  on their respective pulley  325 ,  326  are diametrically opposed with respect to the axis  202 . 
         [0098]    As a variant, the cables  112  and  114  can be wrapped at least partially around the pulleys  325 ,  326  as shown schematically in  FIGS. 16   bis  and  16   ter , or make a complete revolution around these pulleys, in respectively opposite directions, and their second ends are attached to the small bridge  320  by any appropriate means as illustrated at  330  and  340  in  FIGS. 16   bis  and  16   ter . In this case the pulleys  325  and  326  can be free in rotation with respect to the small bridge  320 , on the pins  220 ,  230 . Preferably, the attachment means  330 ,  340  are provided with tension adjustment means as will be described afterward for cables  122 ,  124 ,  132 ,  134 ,  142  and  144 . 
         [0099]    The ends of the pins  220  and  230  carry means  226 ,  236 , such as ball bearings, forming rotation guide bearings for the adjoining end of the beam  104 . 
         [0100]    Between the pulleys  325 ,  326  and the bearings  226 ,  236 , each pin  220 ,  230  carries a cage  222 ,  232  each defining a window for passage and guidance of cables  122 ,  124 ;  132 ,  134  and  142 ,  144 , directed toward the downstream hinges  400 ,  600  and  800 . 
         [0101]    More precisely, each cage  222 ,  232  has two series of respectively coaxial rotating parts, in the shape of diabolos  223 ,  224  and  233 ,  234 . Each series of parts in the shape of diabolos  223 ,  224  and  233 ,  234  is centered on a respective z axis. The diabolo-shaped parts  223 ,  224  provided in the cage  222  are symmetrical with respect to the axis  202 . Likewise, the diabolo-shaped parts  233 ,  234  provided in the cage  232  are symmetrical with respect to the axis  202 . 
         [0102]    Furthermore, each series of diabolo-shaped parts  223 ,  224  and  233 ,  234  includes a number of diabolo-shaped parts equal in number to the cables to be guided, respectively  122 ,  132 ,  142  and  124 ,  134 ,  144 . 
         [0103]    According to the embodiment shown in  FIGS. 10, 11, and 13 , each half-pin  220 ,  230  guides three cables  122 ,  132 ,  142  and  124 ,  134 ,  144 . Consequently, each series of parts  223 ,  224  and  233 ,  234  shaped like a diabolo comprises 3 parts in the shape of a diabolo stacked axially in z. 
         [0104]    A set of 6 diabolos is therefore provided on the axis  202  of the abduction-adduction movement, positioned on the upper portion of the axis to guide the cables  122 ,  132  and  142  as illustrated in  FIG. 16   bis  and a set of 6 diabolos on the lower portion of the axis to guide the cables  124 ,  134  and  144  as illustrated in  FIG. 16   ter . 
         [0105]    Each pair of two adjoining diabolos belonging to the two series of parts  223 ,  224  and  233 ,  234  located in a common cage  222 ,  232  thus define respective passages intended to receive the cables  122 ,  132 ,  142  and  124 ,  134 ,  144 . Each cable is thus guided between two rotating diabolos. 
         [0106]    These passages, crossing along a respective central axis perpendicular to the median plane of the frame  310 , have a symmetry plane which passes through the axis  202  regardless of the relative position of the intermediate assembly  300  with respect to the base  100 , by relative rotation around the axis  202 . 
         [0107]    Each diabolo is capable of rotation around its axis, on a central hinge rod connected to the cage  222  or  232 , to limit friction between the cables  122 ,  132 ,  142  and  124 ,  134 ,  144  and the diabolos. 
         [0108]    A person skilled in the art will understand that the displacement in rotation of the actuator  110  in one direction applies a tension force to the adduction cable  112  and, by acting on the pulley  325  and/or the small bridge  320  leads to a displacement of the finger in the adduction direction (see  FIG. 16   bis ). Conversely, the displacement in rotation of the actuator  110  in the opposite direction applies a tension force to the abduction cable  114  and, by acting on the pulley  326  and/or the small bridge  320 , leads to a displacement of the finger in the abduction direction (see  FIG. 16   ter ). 
         [0109]    In addition, the frame  310  carries 2 series of 3 diabolo-shaped parts located respectively on either side of the small bridge  320  and intended to guide the cables  122 ,  124 ;  132 ,  134  and  142 ,  144  toward the downstream hinges. These diabolos are designated  311 ,  312 ,  313  in  FIG. 16   bis  and  314 ,  315 ,  316  in  FIG. 16   ter.    
         [0110]    As can be seen in  FIGS. 16   bis  and  16   ter , the cables  112  and  114  can also be guided by the respective diabolos  180 ,  190  between their exit from the door defined by the two guide needles  151   bis,    152   bis  and their entry onto the receiving pulleys  325 ,  326 . 
         [0111]    After their passage through the abduction-adduction hinge  200 , each of the 6 cables  122 ,  124 ;  132 ,  134  and  142 ,  144  is thus guided by a diabolo  311 ,  312 ,  313  and  314 ,  315 ,  316  toward the axis of the first flexure-extension movement  400 . Among these cables  122 ,  124 ;  132 ,  134  and  142 ,  144 , 2 cables  122 ,  124  are guided respectively toward the flexure and extension receiving pulleys  525 ,  526 , integral with the axis of the first flexure-extension movement  400 . 
         [0112]    Moreover, the frame  310  carries on its second face a small bridge  350  in the shape of a dihedron, the median plane whereof extends at rest in a xz-plane and which supports in rotation two coaxial flexure-extension half-shafts or pins  420 ,  430  in y centered on the axis  402 . The pins  420 ,  430  are hinged to the adjoining end of the phalange  500  by any appropriate means. 
         [0113]    The two half-shafts or pins  420 ,  430  are located respectively on either side of the small bridge  350 . One of the pins  420  carries two pulleys  422 ,  424  on which the cables  142  and  134  are respectively wound by making one turn around these pulleys. The other half pin  430  carries two pulleys  432 ,  434  on which the cables  144  and  132  are respectively wound by making one turn around these pulleys. The pulleys  422 ,  424  and  432 ,  434  are free in rotation with respect to the small bridge  350  around the axis  402 . 
         [0114]    The dead turn of the cables carried out around the guide pulleys  422 ,  424  and  432 ,  434 , free in rotation around their axes, makes it possible to prevent the cables  132 ,  134  and  142 ,  144  from leaving the pulleys due to the hinge configuration of the flexure-extension movement of the phalanges. 
         [0115]    The ends of the pins  420  and  430  carry means  426 ,  436 , such as ball bearings, forming bearings for guiding in rotation the adjoining end, for example in the shape of a clevis  520  of the first phalange  500 . 
         [0116]    Moreover, the second end of the cables  122 ,  124  is attached to this end of the first phalange  500 , on sides opposite to the axis  402 , as can be seen in  FIG. 15 . 
         [0117]    More precisely, preferably both branches  522 ,  524  of the clevis  520  carries pulleys  525 ,  526  centered on the axis  402 , guiding the second respective end of the cables  122 ,  124 . 
         [0118]    The pulleys  525 ,  526  must be connected in rotation with the clevis  520  if the ends of the cables  122 ,  124  are attached to these pulleys. 
         [0119]    The pulleys  525  and  526  can be free in rotation with respect to the clevis  520 , around the axis  402 , if the ends of the cables  122 ,  124  are attached, not to the aforementioned pulleys, but to the clevis  520 . 
         [0120]    At this level of preference the end of the first phalange  500  adjoining the hinge  400  also has means  530 ,  540  for adjusting the tension of cables  122  and  124 . These adjustment means  530 ,  540  can be subject to many embodiments. 
         [0121]    According to the particular embodiment shown in the appended figures, these adjustment means  530 ,  540  each comprise a fork  532 ,  542  which receives the end of a cable  122  and  124 , for example such an end equipped with a stop knot, and the distance from the axis  402  whereof can be adjusted by a screw  534 ,  544 . 
         [0122]    As can be seen in  FIG. 17 , cylindrical pins  517  preferably allow guiding of the cables  122  and  124  leaving the receiving pulleys  525 ,  526  toward the fine tension adjustment means  530 ,  540  of the cable  122 ,  124 . 
         [0123]    A person skilled in the art will understand that the displacement in rotation of the actuator  120  in one direction applies a tension force on the flexure cable  122  and by acting on the end of the phalange  500  leads to a displacement of the finger in the flexure direction. Conversely, the displacement in rotation of the actuator  120  in the opposite direction applies a tension force on the extension cable  124  and by acting on the end of the phalange  500  leads to a displacement of the finger in the extension direction. 
         [0124]    Finally, 4 cables  132 ,  142  and  134 ,  144  leave the second hinge, via 4 dedicated pulleys  422 ,  424 ,  432  and  434 , so as to be routed respectively toward the flexure-extension movements of the intermediate phalange  700  and flexure-extension movements of the distal phalange  900 . To avoid having these 4 cables  132 ,  142  and  134 ,  144  leave the pulleys due to the hinge configuration of the flexure-extension movement of the proximal phalange  500 , a dead turn on these guide pulleys  422 ,  424 ,  432  and  434 , free in rotation on the movement axis, is carried out. 
         [0125]    The hinges  600  and  800  are preferably similar to the aforementioned hinge  400 . 
         [0126]    Thus the second end or distal end of each phalange  500  and  700  carries a small bridge  550 ,  750  in the shape of a dihedral the median plane whereof extends in a xz-plane and which supports in rotation two respective coaxial flexure-extension half-shafts or pins  620 ,  630  and  820 ,  830  in y centered on the axes  602  and  802 . The pins  620 ,  630  and  820 ,  830  are hinged to the adjoining end of the following phalange  700 ,  900  by any appropriate means. 
         [0127]    The two half-shafts or pins  620 ,  630  are located respectively on either side of the small bridge  550 . Each pin  620 ,  630  carries a pulley  622 ,  632  on which the cables  142  and  144  are respectively wound by making one turn around these pulleys. The pulleys  622 ,  632  are free in rotation with respect to the small bridge  550  around the axis  602 . 
         [0128]    The ends of the pins  620  and  630  carry means  626 ,  636 , such as ball bearings, forming bearings for guiding in rotation the adjoining end, for example in the shape of a clevis  720  of the second phalange  700 . 
         [0129]    Moreover, the second end of the cables  132 ,  134  is attached to this end of the second phalange  700 , on opposite sides of the axis  602 . 
         [0130]    More precisely, preferably the two branches  722 ,  724  of the clevis  720  carries pulleys  725 ,  726  centered on the axis  602 , guiding the respective second end of the cables  132 ,  134 . 
         [0131]    At this level of preference, the end of the second phalange  700  adjoining the hinge  600  also has means  730 ,  740  for adjusting the tension of the cables  132  and  134 , similar to the aforementioned means  530 ,  540 . 
         [0132]    A person skilled in the art will understand that the displacement in rotation of the actuator  130  in one direction applies a tension force on the flexure cable  132  and, by acting on the end of the phalange  700  leads to a displacement of this phalange of the finger in the flexure direction. Conversely, the displacement in rotation of the actuator  130  in the opposite direction applies a tension force on the extension cable  134  and, by acting on the end of the  700  leads to a displacement of the finger in the extension direction. 
         [0133]    Similarly, the two half-shafts or pins  820 ,  830  are located on either side of the small bridge  750 . 
         [0134]    The ends of the pins  820  and  830  carry means  826 ,  836 , such as ball bearing, forming bearings for guiding in rotation the adjoining end, for example in the shape of a clevis  920  of the third phalange  900 . 
         [0135]    Moreover, the second end of the cables  142 ,  144  is attached to this end of the third phalange  900 , on opposite sides of the axis  802 . 
         [0136]    More precisely, preferably the two branches  922 ,  924  of the clevis  920  carries pulleys  925 ,  926  centered on the axis  802 , guiding the respective second end of the cables  142 ,  144 . 
         [0137]    At this level of preference, the end of the third phalange  900  adjoining the hinge  800  also has means  930 ,  940  for adjusting the tension of the cables  142  and  144 , similar to the aforementioned means  530 ,  540 . 
         [0138]    A person skilled in the art will understand that the displacement in rotation of the actuator  140  in one direction applies a tension force on the flexure cable  142  and, by acting on the end of the phalange  900 , leads to a displacement of this phalange of the finger in the flexure direction. Conversely, the displacement in rotation of the actuator  140  in the reverse direction applies a tension force on the extension cable  144  and, by acting on the end of the phalange  900 , leads to a displacement of the finger in the extension direction. 
         [0139]    According to the invention, the transmission of the movement between each actuator  110 ,  120 ,  130  and  140  and the respective hinge  200 ,  400 ,  600  and  800  is accomplished by cables  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144 . More precisely, two transmission cables are provided for each hinge  200 ,  400 ,  600  and  800 . Each cable  112 ,  114 ;  122 ,  124 ;  132 ,  134  and  142 ,  144  is attached, on the one hand at a drive pulley  113 ,  115 ;  123 ,  125 ;  133 ,  135  and  143 ,  145  on the actuator side and on the other hand, at a receiving pulley  325 ,  326 ,  525 ,  526 ,  725 ,  726 ,  925 ,  926  on the hinge side. 
         [0140]    As was previously described, the 3 phalanges of a finger conforming to the invention are made according to the same principle. This offers in particular the following advantages: 
         [0000]    the possibility of modulating the length of each phalange according to the application,
 
the possibility of attaching a cowling,
 
the possibility of routing the instrumentation signals,
 
the possibility of integrating instrumentation for measuring position and force.
 
         [0141]    The finger previously described comprises a passage of cables over guide pulleys at the hinges  400 ,  600  and  800 . The result at this level is variations of length of the cables induced by the displacement in articulation of the phalanges placed downstream. However, the coupling relations can be calculated numerically based on the diameters of the pulleys and the induced variations of length of the cables can be corrected thanks to this mechanical coupling relation between the hinges of a finger and the corresponding gear motors, the coupling relation being of the type: 
         [0000]        Q=A·Q* wherein 
         [0000]    Q=[q 1 , q 2 , q 3 , q 4 ] and represents the movements of the hinges of a finger, A represents the coupling matrix of the finger and
 
Q*=[q 1 , q 2 , q 3 , q 4 ] and represents the movements of the corresponding gear motors.
 
         [0142]    Thus all the hinges can be controlled individually by taking into account the coupling relations in the position control of the finger. 
         [0143]    Modularity in the design of the finger proposed according to the invention allows an assembly of several fingers  10  to construct a robotic hand with several fingers, even an anthropomorphic hand in terms of kinematics and dimensions. 
         [0144]    The combination of several fingers  10  can be created by placing two fingers  10  facing one another having their abduction-adduction axes  202  coaxial or parallel, to accomplish for example a gripper with two facing fingers. 
         [0145]    As illustrated in  FIGS. 19 and 20  one can however assemble on a common base  100  forming a palm several fingers  10  having their first flexure-extension axes  402  coaxial, and facing a finger  10  forming a thumb, so as to propose a device making it possible to have the behavior of a natural hand, even an anthropomorphic hand. 
         [0146]    Illustrated in  FIGS. 19 and 20  is a hand comprising three fingers  10   a,    10   b  and  10   c  having their first flexure-extension axes  402   a,    402   b  and  402   c  coaxial and a thumb  10   d  the abduction-adduction axis whereof  202   d  extends in x, or perpendicularly to the plane containing the abduction-adduction axes  202   a,    202   b  and  202   c  of the aforementioned fingers, while its flexure-extension axes  402   d,    602   d  and  802   d  extend in y. The fingers  10   a,    10   b  and  10   c  and the thumb  10   d  illustrated in  FIGS. 19 and 20  bear numerical references identical to those used previously, to which subscripts a, b, c, and d are appended. 
         [0147]    According to the embodiment illustrated in  FIG. 19 , the actuators  110   d,    120   d,    130   d  and  140   d  have their axes oriented in x. The associated cables extend in z up to the peak of the base, at which said cables are deviated 90° by appropriate return pulleys  170  in the direction of the hinge  200   d  of the thumb  10   d.    
         [0148]    The hand thus obtained allows all the handling that an anthropomorphic hand allows, for example grasping with the palm in all diameters, grasping with the tips of the fingers. 
         [0149]    Within the scope of the invention, “complete actuation” is considered to mean a movement of each hinge, finely controlled in position and in force and independent of the other hinges of the same finger. 
         [0150]    Of course the present invention is not limited to the embodiments described earlier, but extends to all variants conforming to its spirit.