Apparatus for fixing a robotic exoskeleton for lower limbs to the tibial portion of a user's limb

Abstract

Apparatus for fixing a robotic exoskeleton for lower limbs to the tibial portion of a user's limb, which apparatus comprises a support bracket (1) fixed to a mechanical segment (2) of the exoskeleton and a support element (3) of the tibial portion, which support element is couplable to said bracket (1) by means of a connecting member (4). The connecting member (4) comprises a connecting frame (5) connected to the bracket (1) and provided with a plurality of coupling seats (50), a first connecting element (6) alternatively insertable in one of said seats (50), and a second connecting element (7) connected to the first connecting element (6) and fixed to said support element (3).

Description

[0001] APPARATUS FOR FIXING A ROBOTIC EXOSKELETON FOR LOWER LIMBS TO THE TIBIAL PORTION OF A USER'S LIMB

[0002] The present invention relates to an apparatus for fixing a robotic exoskeleton for lower limbs to the tibial portion of a user's limb, which apparatus comprises a support bracket fixed to a mechanical segment of the exoskeleton and a support element of the tibial portion, which support element is couplable to said bracket by means of a connecting member. The connecting member comprises a connecting frame connected to the bracket, a first connecting element, and a second connecting element connected to the first connecting element and fixed to said support element.

[0003] In the development of wearable robotic devices intended for a wide end-user population, adaptability problems arise due to significant variations in the anthropometry among humans. The most traditional approach is the introduction of components in different sizes (generally referred to as small / medium / large sizes), each of which targets a limited segment of the overall user population. This approach is inefficient when designing modular robotic devices capable of adapting to a wide population, since a limited subset of dimensions constitutes an approximate and imperfect adaptation for the different anatomical proportions of all the intended users.

[0004] In assistive and rehabilitative robotics, one of the fundamental aspects in the design of a wearable device is the development of all the parts which allow the coupling between the machine and the user: this is because an efficient human-machine interaction (HMI) allows the patient to benefit from all the advantages which exoskeleton-guided rehabilitation can offer, while poorly designed interfaces could cause severe pain and injuries. In this field, it is common practice to establish such connections along the user's limbs where the robotic mechanical segments or connections are fixed to the user in specific anatomical positions by means of harnesses, allowing the transmission of ferees and motion from the exoskeleton to the user during the performance of any assisted activity. Such a harness is generally conceived as a combination of a connecting element rigidly constrained to the mechanical segment of the robotic device on the one hand, while a support element creates the interaction between the human being and the connecting element on the other, resulting in a physical HMI.

[0005] The need to provide the most comfortable HMI to each user implies that the harness must follow the adaptation obtained by the modular robotic device without altering the performance of the interaction (for example, affecting a different anatomical position due to the adjustment), thereby making the support element rigidly coupled to the robotic mechanical connection.

[0006] When related to exoskeletons for rehabilitation, determining the most suitable position of the user-machine connection is essential to prevent discomfort and pain in users often suffering from physical and / or sensory impairments. This makes factors such as bone geometry and fat distribution of great relevance in defining and developing an effective HMI. Furthermore, direct contact between the user and the rigid support elements is highly discouraged to avoid any discomfort and injury resulting from the implementation of a rigid connection.

[0007] This leads to the introduction of a fabric connecting element (known as brace) which receives the surface of the limb, while a further deformable padding acts as an interface between the user and the support element. The brace, together with a yielding mechanism, increases comfort during use and allows the user a permissible margin of freedom of movement. The implementations thus discussed translate into a system which fixes the circumference of the user's limb through the brace to the support element rigidly coupled to the mechanical connection of the robotic device.

[0008] Rehabilitation exoskeletons can also require further adjustments due to the occurrence of anatomical deviations from standardized anatomical ranges. These deviations lead to the situation where the standard coupling between the rigid element and the robotic mechanical arm may not be sufficient and additional functionalities must be introduced. One of these cases is related to the internal / external angular orientation of the distal bone segment (the tibia) with respect to the proximal one (the femur) on the frontal plane, conditions commonly known as genu valgum and genu varus, respectively. These conditions become relevant when related to lower limb exoskeletons due to their high frequency of occurrence. If the HMI is made with harnesses which cannot adapt to these scenarios, the user's limb is subject to an unintentional state of stress. Other cases of deviation can result from traumatic accidents, metabolic or hereditary diseases which can cause bone malconsolidation.

[0009] Apparatuses known in the state of the art have undergone the introduction of more adjustable elements precisely to obtain a better adaptation to the anatomical differences of users, but this comes at the price of an increase in the number of components and wear time.

[0010] US 2022 / 0176548 A1 discloses an exoskeletal device for providing gait / movement assistance to users and, more in particular, systems for applying such devices to a limb of users. An apparatus for harnesses having a support for a limb is disclosed, an axis being defined on which the support of the limb can slide and around which it can rotate. The apparatus disclosed is particularly complex and comprises a high number of components which make it cumbersome and heavy.

[0011] US 11278465 B2 discloses an exoskeleton consisting of elements combined or fixed together, which can be adjustable and be made in a sandwich structure. Such an exoskeleton comprises a large number of components which make it bulky and heavy, and no possibility of adjusting the position of the tibial portion of the exoskeleton is disclosed.

[0012] KR 20220043749 A discloses a wearable assistance device which improves the usability and fit of a wearable unit which constrains an exoskeleton on the user's thigh or lower leg user and stably transmits the assistance force provided by a joint actuator to the thigh or lower leg. The device has a high complexity because it includes a large number of components which make it expensive and complex. Furthermore, no tilting movement of the support element of the tibial portion of the limb is disclosed.

[0013] US 2022 / 0192846 A1 discloses an autonomous exoskeleton device which includes actuators, control units and sensors with unidirectional transmissions and provides a mechanical joint in parallel with a joint of a user. No tilting movement or any possibility of adjustment of the support element of the tibial portion of the user's limb is disclosed.

[0014] CN 213759316 U discloses a protective exoskeleton for the leg which includes a protector for the tibia and a support for the shoe. The protector is designed with a knee pad, an opening frame and a support plate, offering a rotational degree of freedom to adapt to the natural movements of the knee. The position of the protector can be adjusted and opened easily for ease of use. The shoe support has several holes for the laces, allowing the feet to be fixed and thus providing both support and protection to the user.

[0015] CN 114366558 A discloses a detachable exoskeleton for rehabilitation of the lower limbs, designed to be put on quickly. The system includes mechanisms for adjusting the distance between the hip, knee, and ankle, as well as actuation mechanisms for the hip, knee, and ankle joints. These components are arranged symmetrically with respect to the sagittal plane of the human body. The adjustment of the dimensions occurs by means of a motorized system which ensures safety and practicality, quickly adapting to different patient bodies thanks to a simultaneous adjustment mechanism.

[0016] IT 202100002321 A1 discloses a lower limb exoskeleton including a waist or corset group and two leg groups (right and left), connected to the waist group by means of a hip joint. Each leg group comprises at least one femoral segment and one tibial segment, connected to the end of the waist group and to each other by means of hip and knee joints. The system comprises a locking device with a plurality of seats which allow to constrain or release the movement, allowing the adjustable sliding of the parts. The device uses an elastic element to keep the lock in the absence of external action.

[0017] Such devices known in the state of the art prove to be ineffective in daily use, especially considering that the previously described adjustment operations are carried out in clinical settings by therapists and in domestic settings by nurses, family members or caregivers. In the design phase, it should also be considered that these operations can be carried out several times a day, as difficult-to-use adjustment systems become an obstacle to the effectiveness and usability of rehabilitation robots in clinical practice.

[0018] There is therefore currently a need unmet by the state of the art for an easy-to-use and fast to adjust mechanism, which can minimize the time and effort required by a therapist in carrying out the adjustment tasks.

[0019] Furthermore, since the safety of the patient must be guaranteed during each adaptation operation, the therapist should also be aware of the achievement of this condition: visual and / or auditory feedback is thus essential, especially if no tools are involved in the process.

[0020] The present invention aims at overcoming the disadvantages of the apparatuses currently known in the state of the art and at obtaining the aforesaid objects with an apparatus as disclosed at the beginning, wherein furthermore the connecting member is provided with a plurality of coupling seats and the first connecting element is alternatively insertable in one of said seats.

[0021] Therefore, the present invention provides a lightweight and easy- to-use mechanism for an exoskeletal device for lower limbs which can be adjusted to adapt to any user in a wide target population.

[0022] The main objectives of the present invention are:

[0023] • Develop a support which can be adjusted to adapt to a wide range of anthropometric measurements without the need to envisage different sizes;

[0024] • Properly adapt patients with altered anthropometry due to clinical deformities;

[0025] • Maximize user comfort in maintaining an effective HMI. In an exemplary embodiment, the connecting frame is provided with three said seats.

[0026] Such a three-position mechanical adjustment system is able to meet the anthropometric needs of a wide range of users.

[0027] In a further exemplary embodiment, the first connecting element has at least in part a shape complementary to said seats, such that the insertion of the first connecting element inside one said seat creates a male-female shape coupling between the first connecting element and said seat.

[0028] Thereby, by means of the male-female shape coupling structure, the adjustment can be carried out manually in a short period of time and a correct transmission of the loads between the limb interface and the support bracket and therefore to the exoskeleton is guaranteed, in the assembled condition of the connecting member.

[0029] According to a further embodiment, the connecting frame is oriented along a horizontal axis and said seats are arranged aligned along said axis.

[0030] This allows the apparatus to be adjusted in a wide variety of different anthropometric features of the users.

[0031] In an embodiment, one or more magnets are provided in each coupling seat and / or on the first connecting element for the removable coupling between the first connecting element and the coupling seat.

[0032] The use of magnetic elements facilitates the assembly procedure while simultaneously providing auditory feedback for the therapist, as the magnetic coupling generates a recognisable distinctive sound when the parts come into contact.

[0033] According to a further embodiment, for each coupling seat the connecting frame is provided with at least one through hole, the first connecting element being provided with at least one engagement hole in a position such that such an engagement hole is aligned with said through hole in the inserted condition of the first connecting element in one said coupling seat, a retaining pin being provided insertable in said through hole and in said engagement hole to stably lock the first connecting element in the coupling seat.

[0034] Such a retaining pin prevents unwanted disassembly of the parts during use. This allows to improve the intrinsic mechanical safety of the apparatus, preventing unwanted disconnections during the use of the exoskeleton.

[0035] According to an exemplary embodiment, the second connecting element is rotatably fixed to the first connecting element within a predetermined angular excursion.

[0036] The ability to rotate the user interface within a certain angular excursion according to the forces flowing from the user to the exoskeleton allows to maximize the distribution surface of ferees, increasing comfort.

[0037] In an embodiment, the second connecting element is fixed to the first connecting element by means of a hinge having a horizontal axis, and the first connecting element and the second connecting element being provided with reciprocal abutment surfaces, which abutment surfaces are opposite each other with respect to the hinge and are shaped so that they act as an end-of-stroke for said predetermined angular excursion.

[0038] According to an embodiment, said support element is at least partly made of fabric.

[0039] The interface of the limb, at least partly made of fabric, allows to adapt the support element to the user as much as possible and thus increase comfort for the user.

[0040] The present invention allows to obtain a series of advantages which can significantly improve the scope of application. Firstly, one of the main strengths is the ability to minimize the number of components required for its operation. This means greater efficiency and leaner design, reducing waste and simplifying the assembly process. A further important benefit is the simplification of the adjustment operation for therapists. Thereby, operators can adjust the device easily and quickly, without the need to use additional or complicated tools. This saving of time and effort is crucial to ensure more efficient treatments and optimise the time available to professionals. These and other features and advantages of the present invention will become clearer from the following disclosure of some exemplary embodiments illustrated in the accompanying drawings, in which:

[0041] Fig. 1 illustrates a front view of the apparatus;

[0042] Fig. 2 illustrates a side view of the apparatus;

[0043] Fig. 3 illustrates a top view of the apparatus;

[0044] Fig. 4 illustrates a rear view of the connecting member in the disassembled condition;

[0045] Fig. 5 illustrates a rear view of the connecting member in an assembled condition with the engagement pin;

[0046] Figs. 6 and 7 illustrate two views of the apparatus coupled to the mechanical segment of the exoskeleton;

[0047] Figs. 8 and 9 illustrate the extreme end-of-stroke positions of the rotation of the second connecting element with respect to the first connecting element;

[0048] Fig. 10 illustrates the forces in play;

[0049] The invention relates to a support for the tibial portion of a lower limb for robotic application capable of being adjustable to accommodate a wide population of end users in a robotic exoskeleton of the lower limb. The support of the tibial portion consists of a rigid structure which connects the element to the robot, a soft fabric support for the user wearing the brace and a rapid release system for the manual positioning of the fabric support on the main frame of the robot.

[0050] Figures 1 to 3 illustrate different views of a preferred exemplary embodiment of the apparatus.

[0051] The apparatus comprises a support bracket 1 fixable to a mechanical segment 2 of the exoskeleton and a support element 3 of the tibial portion, illustrated with a dashed line in Figure 3, which support element 3 is couplable to the bracket 1 by means of a connecting member 4.

[0052] The bracket 1 is arched and has a first end 10 provided with fixing means to the exoskeleton, preferably consisting of seats for fixing screws, and a second end 11 fixed to the connecting member 4. The connecting member 4 comprises a connecting frame 5 connected to the bracket 1 and provided with a plurality of coupling seats 50, a first connecting element s insertable alternatively in one of the seats 50, and a second connecting element 7 connected to the first connecting element 6 and fixed to the support element 3.

[0053] The connecting frame 5 is frame-shaped so as to identify therein an elongated through opening 52 aligned with a horizontal or substantially horizontal axis in the worn condition of the exoskeleton. Such a through opening 52 identifies three coupling seats 50 for the first connecting element 6, which seats 50 are aligned along the horizontal axis in sequence respectively in a position close to the bracket 1 , an intermediate position, and an extreme position away from the bracket 1 . The three seats 50 in the different positions ensure the adjustability of the position of the support element 3 with respect to the exoskeleton segment 2. It is also possible to provide only two seats 50 or alternatively more than three seats 50.

[0054] The first connecting element 6 has a shape complementary to the seats 50, so that the insertion of the first connecting element 6 inside a seat 50 creates a male-female shape coupling between the first connecting element 6 and such a seat 50. In particular, the first connecting element 6 is provided with an insertion portion which has a complementary shape to the portion of through opening 52 defining the single seat 50 and a portion adapted to remain external with respect to the through opening 52. However, it is possible to provide a first connecting element which can be completely inserted inside the through opening 52 at a seat 50.

[0055] The through opening 52 allows to visualize the correct insertion position of the first connecting element 6 on both sides of the connecting frame 5; however, it is possible to provide a non-through opening consisting of a suitably shaped groove.

[0056] The first connecting element 6 can be locked in the inserted position in the seat 50 by means of a retaining pin 9. For each coupling seat 50, the connecting frame 5 is provided with at least one through hole 51 , preferably two through holes aligned with each other, of which a first upper hole and a second lower hole. The first connecting element 6 is provided with an engagement hole 60 in a position whereby such an engagement hole 60 is aligned with the through holes 51 provided in the connecting frame 5 in the inserted condition of the first connecting element 60 in a coupling seat 50. The retaining pin 9 is then inserted in the through holes 51 and in the engagement hole 60 to stably lock the first connecting element 6 in the coupling seat 50.

[0057] Figure 4 illustrates a view of the connecting member 4 in the disengaged condition of the first connecting element 6 in the coupling seat 50, with the arrow indicating the insertion direction.

[0058] Magnets 8 are provided in each coupling seat 50 and on the first connecting element 6 for the removable coupling between the first connecting element 6 and the coupling seat 50. Such magnets can be positioned in any configuration adapted to create a coupling between seat 50 and first connecting element with magnetic retention and possibility of creating an auditory feedback for the user upon the insertion of the connecting element 6 in the seat 50.

[0059] In the example illustrated in the figures, each seat 50 has two grooves 53 made in the connecting frame 5 in the face facing the support element 3 and positioned below and above the through opening 52. The portion of the first connecting element 6 adapted to remain external with respect to the through opening 52 in the coupled condition of the first connecting element 6 in the seat 50 is provided with two wings 60 of complementary shape to the grooves 53 and insertable therein. In the abutment surfaces between a groove 53 and a corresponding wing 60, four magnets 8 are provided, two of which are provided in the groove 53 and two on the wing 60, in a position such as to come into contact two by two in the inserted condition of the wing 60 in the groove 53.

[0060] It is possible to use magnets 8 only on one of the two components and ferromagnetic material on the other component.

[0061] The adjustment of the position of the first connecting element 6 occurs manually: the therapist detects the tibial tuberosity on the patient for which support is to be provided. The assembly operation involves bringing the first connecting element 6 closer to the connecting frame 5 at the chosen housing seat 50. Here the assembly is guided both by the presence of a shape coupling between the two parts, and by the presence of the magnets 8 placed on both components. Thereby, the assembly operation is facilitated for the therapist and at the same time a force is guaranteed which favours the coupling between the parts. The magnetic force is such as to favour the coupling but to be easily overcome manually by the operator.

[0062] As illustrated in Figure 5, once the desired position has been selected, the therapist must manually insert the retaining pin 9 in the special seat, i.e., in the through hole 51. The retaining pin 9 in the engaged condition has the safety function of preventing the unintentional disassembly of the first connecting element 6 from the seat 50, acting as a further safety with respect to the magnets 8. The retaining pin 9 is inserted in the longitudinal direction in the seat 50, i.e., in a direction perpendicular to the insertion direction of the first connecting element 6 in the seat 50, since the analysis of the stresses acting on the system shows that there are no direct forces in the direction of removal of the retaining pin 9, thus guaranteeing additional safety.

[0063] Instead of providing a retaining pin 9 of length such as to engage both the upper and lower through holes 51 , it is possible to implement a further safety element, for example a further retaining pin 9, in the lower part of the connecting frame 5.

[0064] The first connecting element 6 thus assembled is therefore integrally constrained to the structure of the exoskeleton by means of the connecting bracket 1 .

[0065] Figures 6 and 7 illustrate two views of the connection of the apparatus to a mechanical segment 2 of the exoskeleton for lower limbs, in particular the tibia link thereof.

[0066] The second connecting element 7 is fixed to the first connecting element 6 in a rotatable manner within a predetermined angular excursion. Thereby the support element 3 can rotate about an axis depending on the application.

[0067] The second connecting element 7 is fixed to the first connecting element 6 by means of a hinge 67 having a horizontal axis, and the first connecting element 6 and the second connecting element 7 being provided with reciprocal abutment surfaces. The rotation occurs by means of a connecting pin of the hinge 67, which connecting pin is rigidly constrained to the second connecting element 7 and is free to rotate by means of bearings with respect to the first connecting element 6.

[0068] The abutment surfaces are located in opposite positions to each other with respect to the hinge 67 and are shaped so as to act as an end- of-stroke for the predetermined angular excursion. In particular, the end- of-strokes are obtained by means of the geometric shape of the first connecting element 6, which define two maximum tilting angles 70 and 71 of the second connecting element 7 with respect to the vertical direction.

[0069] Once the first connecting element 6 is fixed in the housing seat 50 of the connecting frame 5, the only movement allowed is the relative rotation between the first connecting element 6 and the second connecting element 7 tilting within the envisaged limits.

[0070] The tilting allows the automatic repositioning of the support of the second connecting element 7 depending on the direction of application of the force, which varies according to the action carried out by the user: this guarantees exploiting the maximum surface of the support element 3 and optimally distributing the loads on the patient's limb, increasing overall comfort.

[0071] Advantageously, the support element 3 is at least partly made of fabric to promote the user's comfort.

[0072] The diagram of forces acting on the system during the support phase is presented in Figure 10, which schematically illustrates a user wearing a lower limb exoskeleton connected by means of the apparatus and using a crutch. The body weight 12 of the user, the constraint reaction the apparatus, and the constraint reaction of the crutch 14 are indicated.

[0073] Biomedical studies on this application have shown that tibial support is of fundamental importance for the user's support during the phase of walking which involves the application of the load on the supporting leg or when descending stairs.

[0074] Therefore, in these operating phases there will be an effort directed in the direction of advancement which must be compensated.

[0075] During the limb advancement phase during walking, there will instead be an effort in the opposite direction.

Claims

CLAIMS1 . Apparatus for fixing a robotic exoskeleton for lower limbs to the tibial portion of a user's limb, which apparatus comprises a support bracket (1 ) fixed to a mechanical segment (2) of the exoskeleton and a support element (3) of the tibial portion, which support element is couplable to said bracket (1 ) by means of a connecting member (4), which connecting member (4) comprises a connecting frame (5) connected to the bracket (1 ), a first connecting element (6), and a second connecting element (7) connected to the first connecting element (6) and fixed to said support element (3), characterized in that the connecting member is provided with a plurality of coupling seats (50) and the first connecting element (6) is alternatively insertable in one of said seats (50).

2. Apparatus according to claim 1 , wherein the connecting frame (5) is provided with three said seats (50).

3. Apparatus according to claim 1 or 2, wherein the first connecting element (6) has at least in part a shape complementary to said seats (50), such that the insertion of the first connecting element (6) inside one said seat (50) creates a male-female shape coupling between the first connecting element (6) and said seat (50).

4. Apparatus according to one or more of the preceding claims, wherein the connecting frame (5) is oriented along a horizontal axis and said seats (50) are arranged aligned along said axis.

5. Apparatus according to one or more of the preceding claims, wherein one or more magnets (8) are provided in each coupling seat (50) and / or on the first connecting element (6) for the removable coupling between the first connecting element (6) and the coupling seat (50).

6. Apparatus according to one or more of the preceding claims, wherein for each coupling seat, (50) the connecting frame (5) is provided with at least one through hole (51 ), the first connecting element (6) being provided with at least one engagement hole (60) in a position such that such an engagement hole (60) is aligned with said through hole (51 ) inthe inserted condition of the first connecting element (60) in said coupling seat (50), a retaining pin (9) being provided insertable in said through hole (51 ) and in said engagement hole (60) to stably lock the first connecting element (6) in the coupling seat (50).

7. Apparatus according to one or more of the preceding claims, wherein the second connecting element (7) is rotatably fixed to the first connecting element (6) within a predetermined angular excursion.

8. Apparatus according to claim 7, wherein the second connecting element (7) is fixed to the first connecting element (6) by means of a hinge (67) having a horizontal axis, and the first connecting element (6) and the second connecting element (7) being provided with reciprocal abutment surfaces, which abutment surfaces are opposite each other with respect to the hinge (67) and are shaped so that they act as an end-of-stroke for said predetermined angular excursion.

9. Apparatus according to one or more of the preceding claims, wherein said support element (3) at least partly consists of fabric.

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