Kinematic structure adapted to be a modular unit for an exoskeleton, and exoskeleton comprising such kinematic structure

Abstract

Kinematic structure (1; T) for limb support for an exoskeleton (5), comprising a fixing portion (2), suitable to be fixed to a support frame (3); an operative portion (4); wherein, between the fixing portion to the support frame and the operative portion, the kinematic structure comprises an articulated chain comprising: a first passive joint assembly (6) comprising a four-bars linkage (9) suitable for making a displacement along an arc of circumference with a substantially horizontal axis of an output section (9b) with respect to an input section (9a) and a first elastic device (10) defining an equilibrium position of said first passive joint assembly (6); a second joint assembly (7), the operative portion (4) being connected thereto, suitable to allow a rotation of flex / extension of said operative portion (4) about at least one second substantially horizontal axis (Y); said second joint assembly (7) comprising a second elastic device; a plurality of hinges (8a, 8b, 8c) with substantially vertical axis (Z), the hinges of said plurality all comprise a respective third elastic device (12) defining an equilibrium position for each hinge.

Description

[0001] KINEMATIC STRUCTURE ADAPTED TO BE A MODULAR UNIT FOR AN EXOSKELETON, AND EXOSKELETON COMPRISING SUCH KINEMATIC STRUCTURE

[0002] TECHNICAL FIELD

[0003]

[0001] . The object of the present invention is a kinematic structure suitable for an exoskeleton.

[0004]

[0002] . In particular, the kinematic structure according to the invention may form a modular structural unit for the exoskeleton.

[0005]

[0003] . A further object of the invention is also an exoskeleton comprising at least one aforementioned kinematic structure.

[0006] STATE OF THE ART

[0007]

[0004] . Physically demanding tasks that involve, for example, manually handling heavy loads, repeated lifting of loads and non-ergonomic work positions can cause injuries or permanent damage to the worker's musculoskeletal system, imposing a poor quality of life and resulting in incapacity for work, with consequent costs for society. In fact, many people suffer from chronic back pain due to wear-and-tear tasks and one of the main causes of this trend is biomechanical overload. In particular, the shoulder joint is very vulnerable.

[0008]

[0005] . In many industrial contexts, automation and robotization of production plants have reduced the physical workload for operators, however the need to perform certain physical tasks manually remains essential. Compensation for the weight of the human limbs is important in reducing the muscle fatigue experienced by manual workers thereby reducing the risk of overexertion injury or bone fatigue to the upper limbs as well as the lower limbs. For example, simple upper limb braces do not provide satisfactory performance and may cause discomfort when moving the affected limb. Manual operations very often require not only physical performance but also precision in terms of craftsmanship and quality finishes.

[0009]

[0006] . To assist manual workers in their physical tasks, wearable exoskeletons suitable forsupporting the weight of a user, such as an exoskeleton wearer, are generally known, which can also be suitable for assisting the user in lifting and transporting loads even over long distances.

[0010]

[0007] , In addition, exoskeletons are also typically used in the rehabilitation sector.

[0011]

[0008] . It should be reminded that even in the technical sector of sports equipment, such as training facilities for gyms or simulators for Olympic equipment, the specificity and personalisation of training and development programmes for athletes require the implementation of dedicated biomechanical technologies that can provide articulated kinematic structure borrowed from the primary technical sector for the design of the solution itself.

[0012]

[0009] . Additionally, exoskeletons have also been proposed in the field of defence.

[0013]

[0010] . Some known exoskeleton solutions may provide active or motorized parts to assist structural functions.

[0014]

[0011] . By contrast, passive exoskeletons have been proposed, which are free from the need for an electrical power supply and are, for example, equipped with spring-damper assemblies to support the upper limbs against the force of gravity.

[0015]

[0012] . According to some known examples, as shown in the prior art document US 11,787,040, an exoskeleton can be formed by four modular units that are all operatively connected to a lumbar-spinal support frame.

[0016]

[0013] , The support frame can mount a power and control unit to manage active compensation actuators in order to control the active response of the rotational joints arranged downstream, that is, in the distal direction, in the articulated kinematic structure that is worn by the user's limb. Such a solution is shown, for example, in the prior art document US 2021 / 237,259.

[0017]

[0014] . The known exoskeletons, however, are not without drawbacks and are often perceived as rigid, i.e. poorly flexible, by the user and therefore uncomfortable to wear for prolonged periods. The active compensation of the actuators at the level of the rotational joints of the articulated chains supporting the user's limbs (for example, the shoulder-armarticulated unit) is not always accurate and can still weigh on ergonomics, in addition to the fact that the power and control unit has weights and dimensions that further load the lumbar frame.

[0018]

[0015] , Therefore, the need is strongly felt to provide an ergonomic exoskeleton solution that is lightweight and at the same time adapts better to the user's movements than the known solutions

[0019] SUMMARY OF THE INVENTION

[0020]

[0016] , The object of the present invention is therefore to devise a solution to the shortcomings noted with reference to the prior art.

[0021]

[0017] , This and other objects are achieved with a kinematic structure according to claim 1, as well as with an exoskeleton according to claim 7.

[0022]

[0018] . Some advantageous embodiments are the subject-matter of the dependent claims.

[0023]

[0019] . According to an aspect of the invention, a kinematic structure for limb support for an exoskeleton comprises a fixing portion, suitable to be fixed to a support frame, and an operative portion.

[0024]

[0020] . Between the fixing portion to the support frame and the operative portion, the kinematic structure comprises an articulated chain comprising:

[0025] - a first passive joint assembly comprising a four-bars linkage suitable for making a displacement along an arc of circumference with a substantially horizontal axis of an output section with respect to an input section and a first elastic device defining an equilibrium position of said first passive joint assembly; and

[0026] - a second joint assembly, the operative portion being connected thereto, suitable for allowing a rotation of flex / extension of said operative portion about at least one substantially horizontal second axis; said second joint assembly comprising a second elastic device; and

[0027] - a plurality of hinges with substantially vertical axis, the hinges of said plurality all comprising a respective third elastic device defining an equilibrium position for each hinge.

[0028]

[0021] . Advantageously, the articulated chain of the kinematic structure is configuredaccording to an architecture with functional stages, comprising:

[0029] - a gravitational compensation stage, formed by the first passive joint assembly;

[0030] - an adaptive compliance stage, formed by the plurality of hinges with substantially vertical axis;

[0031] - a torque-assistance stage, formed by the second joint assembly.

[0032] The adaptive compliance stage is kinematically interposed between the gravitational compensation stage and the torque-assistance stage.

[0033]

[0022] . According to one embodiment, the second joint assembly is an active joint assembly and comprises a series elastic actuator (SEA).

[0034]

[0023] . According to one embodiment, at least some hinges of said plurality are arranged between the first passive joint assembly and the second joint assembly forming an articulated connecting portion between them. In particular, it may be provided for a hinge of said plurality of hinges arranged between the fixing portion and the first passive joint assembly and two hinges of said plurality of hinges arranged in succession between the first passive joint assembly and the second joint assembly, forming an articulated connecting portion between them.

[0035]

[0024] , The articulated connecting portion forms a kinematic decoupling stage configured to absorb adaptive deformations deriving from the interaction between the kinematic structure and the anatomy of the user, reducing the transmission of such deformations towards the second joint assembly.

[0036]

[0025] . According to one embodiment, each of said first elastic device and the third elastic devices comprise an adjusting mechanism to adjust the equilibrium position thereof.

[0037]

[0026] . In accordance with one embodiment, each hinge of the plurality of hinges with vertical axis has its own angular equilibrium position defined by the respective third elastic device, independent of the equilibrium positions of the other joint assemblies of the kinematic chain.

[0038]

[0027] . According to one embodiment, at least one hinge of said plurality of hinges comprises a relative locking device to block the mobility thereof.

[0039]

[0028] . According to one embodiment, at least one hinge of said plurality of hinges comprisesa limitation device for defining the excursion of the angular movement allowed thereby.

[0040]

[0029] . According to one embodiment, also the four-bars linkage of the first passive joint assembly comprises a limitation device for defining the range of the angular movement allowed thereby.

[0041]

[0030] . According to one aspect of the invention, there is provided an exoskeleton suitable for limb support comprising at least one such kinematic structure, and a support frame mounted to the fixing portion of said at least one kinematic structure.

[0042]

[0031] . According to one embodiment, the exoskeleton comprises a first kinematic structure for a user arm, and a second kinematic structure for the other user arm; wherein both said first and second kinematic structure are mounted specularly to the same support frame.

[0043]

[0032] . According to one embodiment, the exoskeleton comprises a first kinematic structure for a user leg, and a second kinematic structure for the other user leg; wherein both said first and second kinematic structure are mounted specularly to the same support frame.

[0044]

[0033] . According to one embodiment, said support frame comprises a lumbar portion provided with a belt and a spinal portion provided with shoulder straps and connected to extend upwards from the lumbar portion by means of a pair of internal joints with horizontal axes not parallel to each other, said internal joints comprising relative elastic elements that define an equilibrium position of the internal joint.

[0045]

[0034] , Thanks to the solutions proposed, the fit is favoured as well as the adaptability of the kinematic chain of the kinematic structure of the exoskeleton itself to the local anatomical conformation of the user.

[0046]

[0035] . It allows to provide, in particular, an exoskeleton having unusual ability to adapt locally to the user's body while being compact and light, and capable of supporting a wide variety of movements of the user.

[0047]

[0036] . Said exoskeleton can be applied in the field of exoskeletons to assist the heavy manual tasks of the user.

[0048]

[0037] , Said exoskeleton can find application in the field of rehabilitation or personalized sports training.BRIEF DESCRIPTION OF THE DRAWINGS

[0049]

[0038] . Further features and advantages of the invention will appear from the following description of preferred embodiments with reference to the accompanying figures, given by way of non-limiting example, wherein:

[0050] - Figure 1 is a scheme of a kinematic structure, according to one embodiment;

[0051] - Figure 2 is a scheme of a kinematic structure, according to one embodiment;

[0052] - Figure 3 is an axonometric view of an exoskeleton, according to one embodiment;

[0053] - Figure 4 is an axonometric view of an exoskeleton, according to one embodiment;

[0054] - Figure 5 shows a portion of the exoskeleton of Figure 3;

[0055] - Figure 6 shows a portion of the exoskeleton of Figure 4;

[0056] - Figure 7 is an axonometric view of an exoskeleton, according to one embodiment;

[0057] - Figure 8 is a vertical elevation view of a support structure, according to one embodiment; - Figure 9 is a view of the support structure of Figure 8 made according to the point of view indicated by the arrow IX in Figure 8.

[0058]

[0039] . Of course, in this disclosure reference to "one" embodiment is not necessarily intended to indicate the same embodiment and is to be understood as at least one. Furthermore, for reasons of conciseness and reduction of the total number of figures, a certain figure may be used to illustrate the characteristics of more than one embodiment, and not all elements of the figure may be necessary for a certain embodiment.

[0059] DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0060]

[0040] . In accordance with a general embodiment, a 1, T kinematic mechanism is provided. The kinematic structure 1, T is particularly suitable, although not uniquely designed, to support a limb for an exoskeleton 5.

[0061]

[0041] . The kinematic structure comprises a fixing portion 2, suitable to be fixed to a support frame 3, and an operative portion 4. In between the fixing portion 2 to the support frame 3 and the operative portion 4, the kinematic structure comprises an articulated chain.

[0042] , The operative portion 4 preferably comprises a wearable element to be worn by a limb of a user of the exoskeleton or a fixing portion intended for fixing to the user. The operative portion 4 is intended for the application of a load, such as for example a moment or a torque.

[0062]

[0043] , The articulated chain of kinematic structure is configured according to an architecture with functional stages, comprising:

[0063] - a gravitational compensation stage, formed by the first passive joint assembly;

[0064] - an adaptive compliance stage, formed by the plurality of hinges with substantially vertical axis;

[0065] - a torque-assistance stage, formed by the second joint assembly.

[0066] The adaptive compliance stage is kinematically interposed between the gravitational compensation stage and the torque-assistance stage.

[0067]

[0044] . The articulated chain comprises a first passive joint assembly 6, devoid of motorized actuators. The first passive joint assembly 6 may comprise one or more rotational joints having a substantially horizontally directed axis X. In particular, the first passive joint assembly 6 comprises a four-bars linkage 9. The four-bars linkage 9 comprises four hinges thereof with substantially horizontal axis X, wherein, preferably, the horizontal axes of the hinges of the four-bars linkage 9 are directed sagittally with respect to the user. In accordance with a preferred embodiment, the four-bars linkage 9 is an articulated parallelogram.

[0068]

[0045] . The first passive joint assembly 6 with said four-bars linkage 9 is adapted to perform a displacement along an arc of circumference with a substantially horizontal axis of an output section 9b with respect to an input section 9a. The provision of the first passive joint assembly 6 with its four-bars linkage 9 allows a fine adjustment of the conformation of the kinematic chain so as to make it adaptable to a variety of different bodies, resulting in a high customization for different users. In particular, it is possible to adjust the vertical position of the portion of the kinematic chain arranged downstream of the four-bars linkage 9. Furthermore, in the case of a kinematic structure 1 for the arm joint, the provision of the first passive joint assembly 6 allows a lifting or lowering movement of the shoulder.

[0069]

[0046] . Said first passive joint assembly 6 further comprises a first elastic device 10 definingan equilibrium position of said first passive joint assembly 6. In this way, it is possible to provide an equilibrium position for said first passive joint assembly, since the provision of the first elastic device 10 compensates for the force of gravity, i.e. the weight of the kinematic chain of the kinematic structure itself. Preferably, the first elastic device 10 is a spring, such as a helical spring, suitable for working in tension, i.e. suitable for exerting a direct elastic return force along its longitudinal extension axis.

[0070]

[0047] . According to one embodiment, the four-bars linkage 9 of the first passive joint assembly 6 comprises a limitation device (not shown) for defining the range of the angular movement allowed thereby. For example, the limitation device may consist of a pin stably associated with an arm of the four-bars linkage and adapted to interfere with the arm parallel thereto to prevent the approach of the two arms beyond a certain threshold.

[0071]

[0048] . Furthermore, the articulated chain comprises a second joint assembly 7, suitable to allow a rotation of flex / extension about at least one substantially horizontal second axis Y which is substantially orthogonal, when in operating conditions, to the first substantially horizontal axis X of the hinges of the four-bars linkage 9. The second joint assembly 7 comprises a second elastic device, such as for example a torsional spring or an axial spring.

[0072]

[0049] . The second joint assembly 7 is preferably an active joint assembly in that it preferably comprises a motorized rotary actuator. In accordance with a preferred embodiment, the second joint assembly 7 comprises a motorized rotary actuator comprising a servomotor and the second elastic device is arranged in series to the servomotor.

[0073]

[0050] . Preferably, the second joint assembly 7 comprises a series elastic actuator 11 (abbreviated as "SEA"). The series elastic actuator 11 realizes both the motorized rotary actuator and the second elastic device. In this way, the geometric variations of the kinematic chain due to the local anatomical adaptation of the user are at least partially isolated with respect to the second joint assembly 7, allowing assistance to the torque less sensitive to the adaptive deformations of the wearable structure. For example, the kinematic structure may comprise a substantially circumferential mounting flange that receives therein the series elastic actuator 11 made in the form of a disc-shaped body. In one embodiment, the jointassembly 7 can be active, but the relative actuator could be integral with a fixed support external to the kinematic structure, for example at the support frame 3, and there could be a motion transmission system from the actuator to the joint assembly 7.

[0074]

[0051] , In accordance with a preferred embodiment, the second joint assembly 7 comprises an electronic control unit configured to control the motorized actuator. The electronic control unit can be adapted to define the equilibrium position of the second joint assembly 7. The electronic control unit may be included in the series elastic actuator 11.

[0075]

[0052] , The second horizontal axis Y of the second joint assembly 7 is non-parallel to the first horizontal axis X of the hinges of the four-bars linkage 9 and is preferably oriented, in a definable projection on a horizontal plane, when in operating conditions, substantially orthogonal to the first horizontal axis X. In other words, while the first horizontal axis X is directed in the sagittal direction with respect to the user, the second horizontal axis Y is directed in the transverse direction with respect to the user. Of course, in some transport and / or storage configurations of the kinematic structure as well as the exoskeleton, the first horizontal axis X and the second horizontal axis Y can be parallel to each other.

[0076]

[0053] . The first passive joint assembly 6 is arranged, along the kinematic chain, between the attachment portion 2 to the support 3 and the second joint assembly 7, therefore the second joint assembly 7 is interposed between the first passive joint assembly 6 and the operative portion 4. In other words, moving along the kinematic chain from the attachment portion 2 to the support towards the operative portion 4, one first encounters the first passive joint assembly 6 and then the second joint assembly 7. In particular, the operative portion 4 is connected to the second joint assembly 7.

[0077]

[0054] . The articulated chain also comprises a plurality of hinges 8a, 8b, 8c with substantially vertical axis Z. In accordance with one embodiment, each hinge of the plurality of hinges 8a, 8b, 8c with substantially vertical axis has its own angular equilibrium position defined by the respective third elastic device, independent of the equilibrium positions of the first passive joint assembly and the second joint assembly. The hinges 8b, 8c of said plurality are preferably arranged between said first passive joint assembly 6 and said second jointassembly 7 along the extension of the kinematic chain. In accordance with a preferred embodiment, at least two hinges 8b, 8c with a vertical axis Z of the hinges of said plurality are arranged between said first passive joint assembly 6 and said second joint assembly 7, making an articulated connecting portion 18 between said first passive joint assembly 6 and said second joint assembly 7. The articulated connecting portion forms a kinematic decoupling stage configured to absorb adaptive deformations deriving from the interaction between the kinematic structure and the user's anatomy during use, reducing the transmission of such deformations towards the second joint assembly. In this way, it is possible to make a double joint articulated connection between said first passive joint assembly 6 and said second joint assembly 7, which allows the kinematic structure 1, T to adapt to the anatomy of its user and to arrange the second horizontal axis Y of the second joint assembly 7 substantially orthogonal to the first horizontal axis 6 of the hinges of the four-bars linkage 9.

[0078]

[0055] . In accordance with one embodiment, at least one hinge 8a of the hinges of said plurality is arranged between the fixing portion 2 to the support frame 3 and the first passive joint assembly 6.

[0079]

[0056] . Furthermore, the hinges 8a, 8b, 8c of said plurality all comprise a third elastic device 12 thereof defining an equilibrium position for each hinge of said plurality of hinges.

[0080]

[0057] , Other hinges can be provided, in addition to said hinges 8a, 8b, 8c with a vertical axis Z of said plurality of hinges, although in accordance with a preferred embodiment, all the hinges with a vertical axis Z belong to said plurality of hinges and therefore all have a third elastic device 12.

[0081]

[0058] . The third elastic device 12 is preferably formed by a plurality of springs, wherein each hinge 8a, 8b, 8c of said plurality is associated with a respective spring thereof of said plurality. For example, the springs of said plurality forming the third elastic device 12 are all torsional springs adapted to influence the respective hinge towards an angular position of equilibrium.

[0082]

[0059] . The vertical axis hinges 8a, 8b, 8c of said plurality may further comprise a limitation device for limiting the range of the allowed angular movement of the hinge. For example, thelimitation device may be suitable for limiting the movement allowed by the hinge in a predetermined angular range and preferably belonging to the range 0°- ±40°, or even more preferably 0°- ±30°.

[0083]

[0060] . The hinges 8a, 8b, 8c with vertical axis Z of said plurality may further comprise a locking device for locking a certain hinge in a certain angular position. In this way, a hinge 8 when the locking device is active, does not allow any rotation of a relative input section with respect to a relative output section.

[0084]

[0061] , In accordance with one embodiment, the kinematic structure 1 further comprises at least one adjusting mechanism 13 for adjusting the equilibrium position of the first elastic device 10 of the first passive joint assembly 6 and / or of the third elastic device 12 of the hinges 8a, 8b, 8c of said plurality. The at least one adjusting mechanism 13 may comprise a plurality of individual adjusting mechanisms to adjust the equilibrium position of the first elastic device 10 of the first passive joint assembly 6 and / or of the third elastic device 12 of the hinges 8a, 8b, 8c of said plurality, individually, i.e. of each hinge 8a, 8b, 8c of said plurality of hinges. For example, an adjusting screw 13 can be provided for each elastic device 10, 12. The provision of the adjusting mechanism 13 may allow adjusting the rest length of a spring of the first elastic device 10 of the first joint assembly 6 or of the third elastic device 12 of the plurality of hinges 8a, 8b, 8c.

[0085]

[0062] . In accordance with a preferred embodiment, three vertical axis hinges 8a, 8b, 8c are provided, wherein a hinge is arranged between the attachment portion 2 and the first joint assembly 6 and two hinges are arranged between the first joint assembly 6 and the second joint assembly 7 to form said articulated connecting portion 18.

[0086]

[0063] . In accordance with one embodiment, as shown for example in Figure 1, a kinematic structure 1 comprises said first elastic device 10 arranged between the fixing frame 2 and a hinge of the output section 9b of the passive joint assembly 6 so as to influence both the at least one hinge 8a with vertical axis Z and the four-bars linkage 9 towards a definable equilibrium position of the first passive joint assembly 6. In this way, the provision of the first elastic device 10 defines an equilibrium position for both the at least one hinge 8a with verticalaxis and the four-bars linkage 9. The at least one hinge 8a with vertical axis Z may be provided with a spring 12 thereof defining the equilibrium position of the hinge 8a, in addition to the spring 10.

[0087]

[0064] . In accordance with one embodiment, shown for example in Figure 2, in a kinematic structure T the first elastic device 10 is mounted between a hinge of the input section 9a and a hinge of the output section 9b of the four-bars linkage 9 of the first passive joint assembly 6. In this case the first elastic device 10 exclusively influences the position of the four-bars linkage 9.

[0088]

[0065] . In accordance with a general embodiment, an exoskeleton 5 is provided for user limb support comprising at least one kinematic mechanism 1, T, according to any of the previously described embodiments. The exoskeleton 5 further comprises a support frame 3, to which the fixing portion 2 of said at least one kinematic structure 1, T is mounted.

[0089]

[0066] . Preferably, the exoskeleton 5 comprises a plurality of said kinematic structure 1 , T all mounted to the same support frame 3.

[0090]

[0067] , In particular, said kinematic structure can form a modular structure suitable to be fixed to the support frame 3. For example, fixing portions 2 all compatible with the support frame 3 may be provided.

[0091]

[0068] . The operative portion 4 of the at least one kinematic structure preferably comprises a wearable portion for the user's limb, such as for example a belt or a band, or a rigid abutment element for fixing to a portion of the user's limb.

[0092]

[0069] . In accordance with one embodiment, the exoskeleton 5 comprises at least a first kinematic structure 1 for a user arm, and at least a second kinematic structure 1 for the other user arm. Both said first and second kinematic structure are mounted specularly to the same support frame 3.

[0093]

[0070] , In accordance with one embodiment, the exoskeleton 5 comprises at least one first kinematic structure T for one user leg, and at least one second kinematic structure T for the other user leg. Both said first and second kinematic structure are mounted specularly to the same support frame 3.

[0071] , In accordance with one embodiment, the exoskeleton 5 comprises at least a first kinematic structure 1 for a user arm, for example the right arm, and at least a second kinematic structure T for a user leg, for example the right leg. The first kinematic structure 1 and the second kinematic structure T do not necessarily have the same articulated chain, that is, the elements of the articulated chain of the first kinematic structure 1 (arm) are not necessarily the same elements of the articulated chain of the second kinematic mechanism T (leg), and in particular they may differ with regard to their respective first passive joint assembly 6. For example, the first kinematic structure 1 (arm) has the first elastic element 10 mounted between the fixing portion 2 and a hinge of the output section 9b of the first passive joint assembly 6.

[0094]

[0072] , With reference to Figures 8 and 9, according to one embodiment, the support frame 3 comprises a lumbar portion 14 and a spinal portion 15, connected to extend upwards from the lumbar portion 14 by a pair of non-parallel horizontal axis internal joints 16, 17. Said two internal joints 16, 17 of the support frame 3 comprise relative elastic elements defining an equilibrium position of the internal joint 16, 17. Advantageously, said internal joints can each be completely structurally analogous to the hinges 8a, 8b, 8c and therefore also each provide a locking device to block the mobility thereof and a limitation device to define the range of the angular movement allowed thereby. The lumbar portion 14 is provided with a belt 23, and the spinal portion 15 is provided with shoulder straps 19 for anchoring to the user's body and transferring the load. Furthermore, the spinal portion 15 is telescopic or in any case of adjustable length, for example by providing two mutually sliding sections 15a, 15b. The lumbar portion 14 provides, specularly arranged with respect to a spinal axis 21, fixing structures 20 for receiving the fixing portion 2 of the kinematic structure T of the leg, while the spinal portion 15 provides, at the upper end, a plate 22 which is provided with similar fixing structures 20 for receiving the fixing portion 2 of the kinematic structure 1 of the arm.

[0095]

[0073] , Well understood, according to one embodiment, the exoskeleton 5 comprises four kinematic structure, each kinematic structure is for a limb of the user (two arms and two legs).

[0096]

[0074] , As mentioned above, said exoskeletal kinematic structure are not necessarily all equalto each other and may differ in terms of the point of application of the first elastic device 10, the number of hinges 8a, 8b, 8c and other structural characteristics, while still remaining in the general scheme of the above.

[0097]

[0075] , In accordance with a preferred embodiment, as shown for example in Figure 5, the kinematic chain of kinematic structure 1 comprises a fixing portion 2 to the support frame 3, and proceeding distally towards the operative portion 4: a hinge 8a with vertical axis Z, a first joint assembly 6 comprising an articulated parallelogram 9 and a spring 10 with its adjusting screw 13, wherein the spring 10 extends from the fixing portion 2 to the articulated parallelogram 9; and then an articulated connecting portion 18 comprising two hinges 8b, 8c with vertical axis Z arranged in succession; and a second joint assembly 7 formed by a series elastic actuator 11.

[0098]

[0076] , In accordance with a preferred embodiment, as shown for example in Figure 6, the kinematic chain of kinematic structure T comprises a fixing portion 2 to the support frame 3, and proceeding in a distal direction towards the operative portion 4: a hinge 8a with vertical axis Z; a first joint assembly 6 comprising an articulated parallelogram 9 and a spring 10 with its adjusting screw 13, wherein the spring 10 extends between two portions of the articulated parallelogram 9; and then an articulated connecting portion 18 comprising two hinges 8b, 8c with vertical axis Z arranged in succession; and a second joint assembly 7 formed by a series elastic actuator 11.

[0099]

[0077] , In a variant, the plurality of hinges with substantially vertical axis is configured to form a kinematically adaptive compliance stage separated from the gravitational compensation stage and the torque-assistance stage.

[0100]

[0078] , The kinematic structure 1 can be applied in other technical fields, such as for robotic arms.

[0101]

[0079] , Therefore, according to a general embodiment, a modular structure for compensating a load (torque) is provided comprising at least one kinematic structure 1, T according to any one of the embodiments described above. An assembly comprising a plurality of said modular structures and a support frame 3 may be provided, wherein the modular structures of saidplurality are all mounted to the same support frame 3.

[0102]

[0080] . It is understood however that what is described above has an exemplary and nonlimiting purpose, therefore, possible variants of detail that may be necessary for technical and / or functional reasons, are considered from now falling within the same protective scope defined by the claims indicated below.

Claims

CLAIMS1. Kinematic structure (1; T) for limb support for an exoskeleton (5), comprising:- a fixing portion (2), suitable to be fixed to a support frame (3);- an operative portion (4);wherein, between the fixing portion (2) to the support frame (3) and the operative portion (4), the kinematic structure (1, 1’) comprises an articulated chain comprising:- a first passive joint assembly (6) comprising a four-bars linkage (9) suitable for making a displacement along an arc of circumference with a substantially horizontal axis (X) of an output section (9b) with respect to an input section (9a) and a first elastic device (10) defining an equilibrium position of said first passive joint assembly (6);- a second joint assembly (7), the operative portion (4) being connected thereto, suitable for allowing a rotation of flex / extension of said operative portion (4) about at least one substantially horizontal second axis (Y); said second joint assembly (7) comprising a second elastic device;- a plurality of hinges (8a, 8b, 8c) with substantially vertical axis (Z).

2. Kinematic structure according to claim 1, characterized in that the hinges of said plurality all comprise a respective third elastic device (12) defining an equilibrium position for each hinge.

3. Kinematic structure according to claim 1 or 2, characterized in that the second joint assembly (7) is an active joint assembly comprising a series elastic actuator (11).

4. Kinematic structure according to any one of the preceding claims, characterized in that it is provided for a hinge (8a) of said plurality of hinges (8a, 8b, 8c) arranged between the fixing portion (2) and the first passive joint assembly (6) and two hinges (8b, 8c) of said plurality of hinges (8a, 8b, 8c) arranged in succession between them, between the first passive joint assembly (6) and the second joint assembly (7), forming an articulated connecting portion (18) between them.

5. Kinematic structure according to any one of the preceding claims, characterized in that each of said first elastic device (10) and said third elastic devices (12) comprises an adjusting mechanism (13) to adjust the equilibrium position thereof.

6. Kinematic structure according to any one of the preceding claims, characterized in that at least one hinge of said plurality of hinges (8a, 8b, 8c) comprises a relative locking device to block themobility thereof.

7. Kinematic structure according to any one of the preceding claims, characterized in that at least one hinge of said plurality of hinges (8a, 8b, 8c) comprises a limitation device for defining the range of the angular movement allowed thereby.

8. Kinematic structure according to any one of the preceding claims, characterized in that the four-bars linkage (9) of the first passive joint assembly (6) comprises a limitation device for defining the range of the angular movement allowed thereby.

9. Exoskeleton (5) suitable for limb support comprising at least one kinematic structure (1, 1’) according to any one of the preceding claims, and a support frame (3) mounted to the fixing portion (2) of said at least one kinematic structure.

10. Exoskeleton according to claim 9, comprising:- a first kinematic structure (1) for a user arm, and- a second kinematic structure (1) for the other user arm;wherein both said first and second kinematic structure are mounted specularly to the same support frame (3).

11. Exoskeleton according to claim 9 or 10, comprising:- a first kinematic structure (T) for a user leg, and- a second kinematic structure (1’) for the other user leg;wherein both said first and second kinematic structure are mounted specularly to the same support frame (3).

12. Exoskeleton according to claim 9 or any subsequent claim, characterized in that said support frame (3) comprises a lumbar portion (14) provided with a belt (23) and a spinal portion (15) provided with shoulder straps (19) and connected to extend upwards from the lumbar portion (14) by means of a pair of internal joints (16, 17) with horizontal axes not parallel to each other, said internal joints (16, 17) comprising relative elastic elements defining an equilibrium position of the internal joint (16,

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