Patent Publication Number: US-2017360646-A1

Title: Exoskeleton and method of operation thereof

Description:
TECHNICAL FIELD 
     The present description relates to exoskeletons. 
     By this term (or by the alternative, perhaps less appropriate, term “orthosis”) are defined devices that may be worn by a user, for example to favour locomotion by subjects who are prevented therefrom, even only temporarily. 
     Technological Background 
     Exoskeletons can be worn by the user, for example on one or more limbs with the purpose of enabling/facilitating a movement of articulation between the proximal branch and the distal branch of the limb with the function of delivering or removing motor energy, obtained for example via expressly provided motor drives. 
     The corresponding prior art comprises, for example, documents such as WO 2012/175211 A1, WO 2015/095211 A2, WO 2015/140352 A1, or WO 2015/140353 A2. 
     Notwithstanding a rather extensive activity of research in the sector, there is still felt the need to have available exoskeletons capable of adapting precisely to the characteristics of the wearer, preventing, for example, the operating modalities of the exoskeleton from possibly, at least in certain conditions, countering the possibilities of movement of the wearer. 
     Object and Summary 
     The object of one or more embodiments is to contribute to providing a response to the above need. 
     According to one or more embodiments, this object is achieved with an exoskeleton having the characteristics recalled in the ensuing claims. 
     One or more embodiments may also refer to a corresponding operating method. 
     The claims form an integral part of the technical teaching provided herein in relation to one or more embodiments. 
     One or more embodiments may provide an exoskeleton system comprising a wearable articulated double structure (in practice, a pair of exoskeletons, a primary one and a secondary one), where the two structures are able to work synergistically for some aspects and separately for others. 
     One or more embodiments enable creation of a first structure that is able to perform, for example, the functions of ambulation and the changes of posture, whereas the second structure has the function of accommodating the person using it, guaranteeing respect of his or her functional limitations. 
     In one or more embodiments, the two structures can be joined so as to guarantee safety of the user, with the capacity of adapting to the degree of functional limitation of the latter. 
     In one or more embodiments, the secondary structure that receives the user, by separating from the primary structure, can enable the latter to complete a movement that the articulation of the person using the device could not perform, safeguarding the state of the articular districts that might be involved in damage. 
     One or more embodiments may envisage creation of an ankle comprising two structures, one with the function of enabling ambulation and the other that receives the user. 
     In one or more embodiments, the ankle of the primary structure may comprise a top (static) platform and a bottom (dynamic) platform connected by a hemisphere. 
     In one or more embodiments, the ankle of the secondary structure may comprise a platform capable of receiving the user. In one or more embodiments, the ankle of the primary structure in no way transfers movement to the ankle of the secondary structure, thus enabling use of the exoskeleton even by a person with serious articular limitations to the lower limbs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One or more embodiments will now be described, purely by way of non-limiting example, with reference to the annexed figures, wherein: 
         FIGS. 1 and 2  are schematic illustrations of the operating criteria of an exoskeleton according to one or more embodiments; 
         FIG. 3  is a schematic perspective view of the structure of an exoskeleton according to one or more embodiments; and 
         FIGS. 4 to 6  illustrate possible details of embodiments. 
     
    
    
     It will be appreciated that, for clarity and simplicity of illustration, the various figures cannot be reproduced at the same scale. 
     DETAILED DESCRIPTION 
     In the ensuing description, various specific details are illustrated aimed at providing an in-depth understanding of various examples of embodiments. The embodiments may be obtained without one or more of the specific details, or with other methods, components, materials, etc. In other cases, known structures, materials, or operations are not illustrated or described in detail so that various aspects of the embodiments will not be obscured. 
     Reference to “an embodiment” or “one embodiment” in the framework of the present description is intended to indicate that a particular configuration, structure, or characteristic described in relation to the embodiment is comprised in at least one embodiment. Hence, phrases such as “in an embodiment” or “in one embodiment” that may be present in various points of the present description do not necessarily refer to one and the same embodiment. 
     The references used herein are provided merely for convenience and hence do not define the sphere of protection or the scope of the embodiments. 
     In the figures, the reference number  10  designates as a whole an exoskeleton that may be worn by a user who finds himself limited, possibly even only temporarily, in performing motor activities. 
     For instance, in one or more embodiments, the exoskeleton  10  may comprise an articulated reinforcement that may be coupled to the body of the wearer P so as to set itself with one or more of its parts on one or more anatomical parts of the wearer P with the function of assisting the wearer P in carrying out motor and postural functions. 
     By way of example (and without this being open to interpretation in any sense limiting the embodiments), the figures of the annexed drawings refer to an exoskeleton  10  that may be worn on at least one of the lower limbs of the user P so as to comprise:
         a first (proximal) member  12 , which is to extend in an area corresponding to a thigh, hence in an area corresponding to the femur, i.e., of the proximal stretch of the limb; and   a second (distal) member  14 , which is to extend at the calf, hence in an area corresponding to the tibia and the fibula, i.e., the distal stretch of the limb.       

     The first and second members  12 ,  14  are connected together through an articulation  16 , which is to be located in a position corresponding to the knee and enables a movement of mutual angular orientation of the first member  12  and of the second member  14  within a certain range of angular orientation. 
     In the case of a normal limb, the range of angular orientation extends between a condition in which the proximal member  12  and the distal member  14  are approximately aligned with one another, forming with respect to one another an angle of approximately 180° (see, for example,  FIG. 1 ) and conditions in which the distal member  14  forms with respect to the proximal member  12  an acute angle, for example in the region of 30° or less. 
     An exoskeleton of the type here considered may on the other hand comprise also other components. 
     For instance, the schematic representations of  FIGS. 1 to 3  exemplify the possible presence of a further articulation H located in an area corresponding to the proximal end of the first member  12  (hence at the hip joint of the wearer), as well as a further articulation  18 , which may function as ankle joint. 
     In one or more embodiments, the various articulations here considered may have associated respective motor drives M 1 , M 2 , M 3 , M 4 , which are able to govern in a positive way the relative movement of orientation of the elements connected by the articulation. These motor drives can be obtained according to known criteria and do not constitute in themselves a specific object of the embodiments. 
     One or more embodiments aim at taking into account the fact that, in one or more conditions of use (for example, with the wearer P sitting on a seat S) the relative movement of angular orientation between the first (proximal) member  12  and the second (distal) member  14  of the exoskeleton may attain angular values (for example, values of acute angle) not allowed by the articular districts of the wearer P, the wearer who, for various reasons, may experience a mobility of the limb (for example, of one or both of the lower limbs) that is limited to the condition in which the distal stretch (i.e., the calf) can be flexed with respect to the proximal stretch (i.e., the thigh) only through a limited angle. 
     Such a condition is exemplified in  FIG. 2  (where the motor drives M 1 , M 2 , M 3 , M 4 —which, on the other hand, are represented only schematically in  FIG. 1 —are not visible for simplicity of illustration). 
     One or more embodiments may envisage that the second (distal) member  14  of the exoskeleton  10  comprises a first structure  14   a  that can be oriented at the articulation  16  with respect to the first (proximal) member  12  over the entire range of angular orientation envisaged for operation of the exoskeleton, i.e., with a capacity of relative orientation that ranges practically from a flat or almost flat angle (as represented in  FIG. 1  with reference to the upright stance) to an acute angle in the region of 50° or less (as exemplified in  FIG. 2  with reference to the sitting condition). 
     One or more embodiments may envisage that the second (distal) member  14  of the exoskeleton  10  likewise comprises a second structure  14   b , which can be coupled to the limb of the wearer (for example, with bands or straps, not visible in the figures). 
     One or more embodiments may then envisage a latch device  20 , which can couple together the first structure  14   a  and the second structure  14   b  of the second (distal) member  14  of the exoskeleton  10 . 
     The latch device  20  (which may present the characteristics exemplified in  FIGS. 4 to 6  and is not visible in  FIGS. 1 to 3  so that the representation will not be too complicated) can be selectively uncoupled at a certain angular position of the range of relative orientation of the first and second members  12 ,  14  of the exoskeleton so as to be able to render the first structure  14   a  orientable with respect to the first member  12  independently of the second structure  14   b.    
     In other words, with the latch device  20  in the engaged or coupling condition, the first structure  14   a  and the second structure  14   b  of the second member  14  of the exoskeleton are connected to one another and move together with respect to the first member  12 , as may be required, for example, in conditions of upright stance, for example during ambulation (see  FIG. 1 ). 
     When, instead, for example to enable the wearer P to sit down on a seat S, it is desirable that the exoskeleton  10  should “bend”, once a certain position of the relative movement of orientation of the first member  12  and of the second member  14  is reached (in particular, with a movement of bending that leads the two members in question to move in the direction such as to form an angle with respect to one another that gradually reduces), the latch device  20  can move into the uncoupling condition, “releasing” the second structure  14   b  from the first structure  14   a  in such a way that:
         the structure  14   a  can proceed in its movement of orientation with respect to the first member  12  (so as to enable, for example, reaching of the sitting position represented in  FIG. 2 ); and   the second structure  14   b  (coupled to the wearer&#39;s limb), being released from the first structure  14   a , does not follow the first structure  14   a  in said movement of orientation beyond a certain angular position, and can thus maintain the wearer&#39;s limb in the condition of maximum bending that can be achieved.       

     In this way, the exoskeleton  10  does not force the limb of the wearer P towards conditions incompatible with the physiological conditions of the wearer. 
     In one or more embodiments, the second structure  14   b  may comprise a resting platform  140  fixed with respect to the second structure  14   b , which is to receive the foot of the wearer P. 
     In one or more embodiments, in addition or as an alternative to the characteristics exemplified previously, it is possible to envisage that the exoskeleton  10  comprises, optionally carried by the first structure  14   a  of the second member  14 , a ball joint  18  including a spherical head  18   a  that engages a socket or bowl  18   b , which is also spherical, set on a terminal platform  22  of the exoskeleton so as to enable this platform to perform movements that are able, for example, to simulate the behaviour of an ankle, including inversion and eversion, enabling performance of motor and/or postural functions such as the ones exemplified in  FIGS. 1 and 2 , without the movements of the exoskeleton having any effect on the wearer P, with the possibility of performing said movements also to the benefit of a person with serious functional limitations to the limbs. 
     From the engineering standpoint, this may correspond to the fact of envisaging that the ball joint  18  can enable the platform  22  to perform, also in combination, movements of pitch (see the arrow B in  FIGS. 1 and 2 ), roll (see the arrow R in  FIG. 3 ), and yaw (see the arrow Y in  FIG. 3 ) with respect to the remaining part of the exoskeleton. 
     In this regard, it will be appreciated that, even though the present detailed description refers, byway of example, to a lower limb, one or more embodiments are suited to being used together with an upper limb, with, for example, the articulation here exemplified by the articulation  16  that is to perform the function of the elbow joint or else of the shoulder joint of the wearer. 
     In the case of application to an upper limb, the platform  22  (and the corresponding ball joint  18 ) can hence enable the functions of orientation of the hand to be performed. 
     In this regard, it will be appreciated moreover that the arrangement of the ball joint  18  can, in one or more embodiments, be reversed with respect to the one exemplified herein, hence with the spherical head  18   a  carried by the platform  22  and the socket or bowl  18   b  carried by the remaining part of the exoskeleton, for example by the second member  14 . 
     The representation of  FIGS. 4 to 6  exemplifies possible criteria of implementation of the latch device  20  that is able to act between the two structures  14   a ,  14   b  of the second member  14  of the exoskeleton. 
     For instance, in one or more embodiments, the device  20  may comprise a cam mechanism, including a cam  200  carried, for example, by the first member  12  and a cam follower  202  carried by the second member  14  and carried by a moving element  204  which can co-operate in conditions of engagement with a pin  206 , with the moving element  204  possibly elastically loaded (for example, via springs  208 ). 
     For instance, in one or more embodiments, it is possible to envisage that the pin  206  and the moving element  204  are carried, respectively, by the first structure  14   a  and the second structure  14   b . In one or more embodiments, the kinematic arrangement may of course be reversed. 
     In one or more embodiments, the latch device  20  may be obtained so as to operate according to the direction of the relative angular movement of orientation between the first member  12  and the second member  14  of the exoskeleton  10 . 
     In one or more embodiments, the relative movement of orientation may occur:
         in a first direction, which leads to smaller angles between the first member  12  and the second member  14 , i.e., with the exoskeleton that bends to enable/produce a movement of flexing of the limb of the wearer P; and   in a second direction, which leads to wider angles between the first member  12  and the second member  14 , i.e., with the exoskeleton that extends to enable/produce a movement of extension of the limb of the wearer P.       

     For instance:
         the first direction of movement is the one that leads from the condition exemplified in  FIG. 1  to the condition exemplified in  FIG. 2  (movement that enables sitting down, passing from the upright stance to a sitting condition); and   the second direction of movement is the one that leads from the condition exemplified in  FIG. 2  to the condition exemplified in  FIG. 1  (movement that enables standing up, passing from a sitting condition to the upright stance).       

     Operation of the cam mechanism exemplified in  FIGS. 4 to 6  can hence occur according to the criteria described hereinafter. 
     When the first and second members  12 ,  14  (and the exoskeleton  10 ) are in the fully extended condition— FIG. 4 —the cam  200  does not engage the cam follower  202 . The moving element  204 , possibly pushed elastically (via the springs  208 ), blocks the pin  206  so that the two structures  14   a ,  14   b , mounted, respectively, on which are the moving element  204  and the pin  206 , are blocked, i.e., latched, together and move together with respect to the first member  12 . 
     When, for example as a result of a movement of bending, the angle between the first member  12  and the second member  14  reduces, reaching a given angular value (possibly in a selectively variable way according to the characteristics of the wearer, for example according to the maximum angle of bending allowed by the wearer&#39;s limb, in line with the criteria exemplified in what follows), the cam  200  starts to engage the cam follower  202 , bringing about gradual sliding of the moving element  204  (for example, against the force exerted by the springs  208 ) in such a way as to determine disengagement of the pin  206 , as schematically exemplified by the sequence of  FIGS. 5 and 6 . 
     In the condition exemplified in  FIG. 6 , the two structures  14   a  and  14   b  of the member  14  are in effect released from one another so that the first structure  14   a  can proceed with the movement of orientation (for example, into the “sitting” condition of  FIG. 2 ), whereas the second structure  14   b , which is connected to the wearer&#39;s limb, remains in the limit angular position compatible with the conditions of the wearer. 
     Operation of the device  20  exemplified by the sequence of  FIGS. 4 to 6  may be performed in the opposite direction, i.e., according to an opposite angular movement, for example to pass from the sitting condition of  FIG. 2  to the upright condition of  FIG. 1 . 
     In this case, the structures  14   a ,  14   b  are initially released from one another ( FIG. 6 ) and, as the exoskeleton  10  shifts towards the extended position, the structure  14   a  tends towards the second structure  14   b , bringing about operation of the cam mechanism  20  according to modalities complementary to the ones described previously, hence ( FIG. 5 ) going into the condition where the structures  14   a ,  14   b  are again engaged with one another so that they move together, being connected to one another, with respect to the first member  12  (condition represented in  FIG. 4 ). 
     In one or more embodiments, it may be envisaged that the mechanism.  20  comprises an arrest element, for example, a pin  2000 , such as to prevent, once there is disengagement from the structure  14   a  (which may proceed in the movement of bending with respect to the first member  12 ), the structure  14   b  from making any further movement in this direction. 
     In this way (as may be appreciated, for example, from  FIG. 2 ), the aforesaid arrest element can support the structure  14   b , which receives the wearer&#39;s limb, preventing any damage to the joint of the wearer himself. 
     In one or more embodiments, the cam  200  and/or the arrest element  2000  can be mounted in an adjustable way, for example by being arranged on a supporting plate, the angular position of which can be selectively modified, for example, by providing, in the aforesaid supporting plate, slits (eyelets)  2004  shaped like the arc of a circle, in which screws  2006  are inserted. By loosening the screws  2006  the plate can be made to turn so as to modify the angular position of the cam  200  and/or of the element  2000  with respect to the load-bearing element (for example, the first member  12 ). In this way, it is possible to select the angular position of relative orientation between the first member  12  and the second member  14 , where there is obtained (for example, according to the modalities exemplified previously) disengagement/engagement of the mechanism  20  and/or the effect of arrest (support of the limb) by the element  2000 . 
     It will be appreciated that the operating modes just described are not prevented, but rather facilitated by the ball joint  18 , which is able, for example, to ensure orientation of the platform  22  in the various conditions of orientation and of relative connection of the other portions of the exoskeleton. 
     It will likewise be appreciated that, in one or more embodiments, the platform  22  may comprise a main body  22   a , associated to which is the ball joint  18 , and an articulated portion  22   b  (at the front, in the example here considered) that can be oriented with respect to the main body  22   a , for example, under the action of the motor drive designated as a whole by M 4  in just  FIG. 1 . This division (and movement) of the platform  22  may enable, for example, reproduction of the movement of bending of the foot (raising and lowering of the toes), which can further facilitate ambulation assisted by the exoskeleton. 
     Again, in one or more embodiments, the platform  22  may have associated (for example, as part of the motor drive designated by M 3  in  FIG. 1 ) flexible orientation wires  220 , which are able to co-operate with the ball joint  18  during reproduction of the natural movements (for example, of the ankle or of the hand, according to whether the exoskeleton here exemplified is applied to a lower limb or an upper limb). 
     Of course, without prejudice to the underlying principles, the details of construction and the embodiments may vary, even significantly, with respect to what has been illustrated herein purely by way of non-limiting example, without thereby departing from the sphere of protection, as this is defined in the annexed claims.