Trunk exoskeleton with mechanical coupling arrangement for activating / deactivating support

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The field of the invention is that of exoskeletons, that is to say mechanical structures which partially duplicate the human skeleton in order to assist it in carrying out a task or activity, such as lifting and carrying a load, or even the execution of repetitive movements.

[0002] In this text, the term "load" means a weight supported by a user, that is to say the weight of a part of his own body possibly added to the weight or force exerted by one or more objects manipulated by the user.

[0003] More specifically, the invention relates to a trunk exoskeleton with an assistive activation / deactivation mechanical coupling assembly.

[0004] The invention finds applications in particular in the field of logistics, and more broadly in fields in which a user is required to lift loads from a low point, requiring the torso to be tilted downwards, then raised, or vice versa. STATE OF THE ART

[0005] Trunk exoskeleton techniques are known from the prior art, allowing their user to be relieved, particularly when lifting loads, handling objects located close to the ground, or when carrying out repetitive tasks requiring frequent bending and straightening.

[0006] Such activities place a high strain on the user's body, particularly in the lumbar region, and promote the development of musculoskeletal disorders (known by the abbreviation "MSD"), which has created a need for such trunk exoskeleton techniques.

[0007] In particular, exoskeleton techniques are known having an upper part connected to the trunk of a user, and a lower part connected to each of the user's lower limbs, the two parts pivoting relative to each other, the pivot point generally being located at the user's hips. In order to provide assistance to the user leaning downwards, a torque is exerted at the pivot point, actively, by means of a motor for example, or passively by an elastic energy storage element, such as a spring for example. According to certain variants, the connection between the upper part and the lower part is made by a flexible blade, which acts as both a connecting element and an energy storage element.

[0008] A significant disadvantage of active-assist exoskeletons is their low autonomy, due to limited energy storage capacity, often electrical, as well as their significant mass, due to actuators and batteries which are generally particularly heavy.

[0009] Another major disadvantage of the aforementioned techniques, particularly passively assisted techniques, is the immediate activation of the assistance as soon as the user's lower limbs are no longer aligned with their trunk. Thus, even during movements or positions requiring no assistance, such as walking, the user works unnecessarily against the elastic element, resulting in significant discomfort or even muscle exhaustion.

[0010] Faced with these problems, known exoskeleton techniques have been improved, by proposing systems allowing the trunk to tilt within a limited angular range around the vertical, before activating assistance when the user leans further. According to variants, such an angular range is adjustable by the user, according to their needs.

[0011] However, these techniques are not fully satisfactory, insofar as they do not differentiate between movements requiring assistance, such as a downward tilt of the trunk, and those requiring no assistance, such as walking. In addition, to allow unhindered walking, the angular range of inactivation must be relatively large, with the disadvantage that no assistance is possible in this range even if it were necessary. Adjusting said range by the user is a particularly tedious solution which cannot be used dynamically and at high frequency.

[0012] Other techniques offer options to partially overcome these problems, such as locking the assistance when it is needed, and unlocking it when it is not needed, allowing the user to walk without the assistance being activated.

[0013] However, these techniques require frequent manipulation of the exoskeleton, which has the disadvantage of being particularly tedious and time-consuming, especially when the user quickly links together phases of movement that need to be assisted and other phases where assistance is not required. In addition, there is a significant risk that the user will forget to unlock or lock the system, resulting in annoyance and disinterest on the part of the user with the system.

[0014] Document US 7744552 B1 describes a trunk exoskeleton comprising a part connected to the user's trunk, lower parts each connected to a lower limb of the user, the lower parts and the upper part being connected by pivots. The lower parts each comprise a pivot shaft provided with an external screw thread, and housed in a pivot housing provided with an internal screw thread, the exoskeleton further comprising an elastic member interposed between the shafts and capable of being compressed by the latter. The screw threads are in opposite directions, so that the exoskeleton is configured to allow walking without assistance, and to provide assistance when the user bends.

[0015] An important requirement that a system that addresses the above-mentioned problems must meet is that it be easily adaptable to any type of user. In particular, it is necessary that the exoskeleton solution can be used by users of different ages, genders, and body shapes without requiring significant modifications or adjustments.

[0016] None of the current systems can simultaneously meet all the required needs, namely to offer a trunk exoskeleton technique that is lightweight and simple in design, that is quick and easy for a user to don by simply adapting to the user, and that provides assistance only when the user needs it, without the user having to actively intervene. STATEMENT OF THE INVENTION

[0017] The present invention aims to remedy all or part of the drawbacks of the state of the art cited above.

[0018] To this end, the invention relates to a trunk exoskeleton comprising: an upper part capable of being connected to the trunk of a user of the exoskeleton, a pair of lower modules each being capable of being connected to a lower limb of the user, each lower module being connected to the upper part by a separate pivot point located at the height of the user's hips, at least one elastic actuator configured to exert, when energized, a compensating moment of force on the user's trunk, a mechanical coupling assembly configured to: ▪ in a working posture of the user, cause the at least one elastic actuator to be energized when the lower modules form substantially the same non-zero angle with the upper part, the exoskeleton then providing assistance, and in a walking posture of the user, allow free counter-phase pivoting of the lower modules, without the exoskeleton providing assistance,

[0019] Thus, the exoskeleton is mainly made up of three main parts, namely the upper part linked to the trunk, and the lower modules linked to the lower limbs, which can pivot around the pivot points. It is understood that thus, these three main parts partly double the user's skeleton, and are articulated substantially at the same level as the user's skeleton, namely at the level of the pelvic joint. It is specified that the position of a pivot point is configured to be positioned relative to the joint between the user's lower limb and hip, in order to hinder the user's walking as little as possible. Such a position generally corresponds to an "anatomical" pivot point between the trunk and the lower limbs,

[0020] Thanks to the elastic actuator, a compensating moment of force can be exerted on the user's trunk, so as to assist him during an upward trunk movement, when he raises his bust. It is understood that the compensating moment of force is exerted "upwards", that is to say that it tends to help the user to get up, and at least makes it possible to counter the moment exerted by the user on the exoskeleton, when he lifts a load on the ground for example. The elastic actuator can take various forms, as will be seen later, and works when it is under tension, it being understood that the terminology "under tension" designates an elastic actuator on which a force is exerted, whether it is a tensile and / or compressive force. This "under tension" state is opposed to the "relaxed" state of the actuator, in which substantially no force is exerted on the latter.

[0021] In addition, the coupling assembly includes: a connecting element coupling the lower modules together, a guiding element of the connecting element, fixed to the upper part, coupling the lower modules to the upper part via the connecting element, the connecting element and the guide element being flexible.

[0022] The exoskeleton can take at least two distinct characteristic states, depending on the user's posture.

[0023] When the user is in a working posture, that is to say when his lower limbs form substantially the same angle with his trunk, the exoskeleton is in an "active" state. The potential energy of the downward movement of the user's trunk is stored in the form of elastic energy in the elastic actuator. This effect is obtained by the presence of the mechanical coupling assembly, the connecting element of which links the lower modules, being fixed by each of its ends to one of the lower modules, the connecting element itself following the rotation of the upper part, being driven by the guide element secured to the upper part. The elastic actuator is arranged so as to be under tension when the connecting element is driven by the guide element, in a working posture.In this way, the exoskeleton “detects” a working position, causing elastic energy to be stored in the elastic actuator(s), for restitution when the user raises their trunk.

[0024] When the user is in a walking posture, that is to say when his lower limbs perform a pendulum or swinging movement, alternating or counter-phase, relative to his trunk, the exoskeleton is in an "inactive" state. In this state, the connecting element can freely move in the guide element, which consequently avoids tensioning the elastic members. Indeed, although a relative movement exists between the upper part and a lower module, the connecting element is not driven by the guide element in this configuration because the alternating movement of the lower modules allows its movement in / on the guide element. Since the elastic actuator is arranged so as to be under tension when the connecting element is driven by the guide element, it is understood that when the connecting element is not driven, in a walking posture, then the elastic actuator is relaxed.In this way, substantially no kinetic energy (from the user's walking) is stored as elastic energy in the exoskeleton when walking.

[0025] In summary, the aforementioned effects are obtained by the fact that the mechanical coupling assembly comprises two separate elements, the connecting element being able to move freely in the guiding element, avoiding any activation of the exoskeleton when walking, and the guiding element driving the connecting element when the trunk is leaning forward, thus activating the exoskeleton by energizing the elastic actuator(s).

[0026] Furthermore, the flexible nature of the connecting element and the guiding element is particularly advantageous with regard to the adaptability of the exoskeleton to different user morphologies, of varying ages and genders. Indeed, the mechanical coupling between the right and left part of the exoskeleton is generally carried out rigidly on the exoskeletons of the prior art, making width adjustment difficult or even impossible. According to the present invention, the flexible nature, also described as "flexible", of the coupling assembly, makes it possible to adapt the exoskeleton to varied waist sizes, without requiring adjustment. In other words, the exoskeleton according to the invention does not have a predefined standard width, but on the contrary a multitude of different widths, extending up to the limit permitted by the length of the coupling assembly.Furthermore, such a design has the advantage of not absorbing any external force, unlike a rigid structure which would then have to be sized to withstand shocks over time, which would imply that the exoskeleton would be more bulky and heavier. Finally, such a flexible design makes it possible to position the coupling assembly as close as possible to the user's body, in an arrangement adapted to their morphology, while avoiding any risk of collision between the user's body and the exoskeleton.

[0027] According to a preferred variant, said flexible connecting element is an elongated element substantially without elastic deformation capacity, and in which said flexible guiding element is a substantially incompressible elongated element.

[0028] In this way, the connecting element can reliably fulfill its coupling role, not being able to deform elastically when a tensile force is exerted on it. Indeed, it is necessary for the connecting element to be able to transmit a force in an active state, in order to put the elastic actuator under tension, which would prove impossible if the connecting element deforms elastically significantly. At the same time, according to a series of implementation variants, it is necessary for the guide element to be substantially incompressible, so as not to deform when a tensile force is exerted on the connecting element, which would also have the effect of making it impossible to put the elastic actuator under tension in an active state.

[0029] In addition, the elongated and flexible nature of the connecting element makes it possible to connect the two sides of the exoskeleton along a path chosen advantageously, such as, for example, an arc of a circle on the user's back. Such an element can also move simply and without constraint in a corresponding guide element, which defines the path followed by the connecting element.

[0030] According to an advantageous variant, said flexible connecting element is a cable, and the flexible guiding element is a sheath of diameter adapted to accommodate said cable.

[0031] In this way, the mechanical coupling assembly is made up in a particularly simple manner, by using commercially available components, making it possible to limit the manufacturing and repair costs of the exoskeleton. A standard sheath is for example composed of an outer plastic sheath which serves as protection, and a sheath made of a spiral steel wire which guarantees incompressibility while preserving a certain flexibility and suppleness. Indeed, a guide element which is too elastic would have the effect of compressing when the connecting element is subjected to traction, which would not allow the coupling assembly to play its role as described above.As regards the connecting element, the use of a standard cable, for example metallic, of the “Bowden” type is a preferred option, presenting significant resistance and being flexible while remaining substantially without elastic deformation capacity.

[0032] However, other variants are possible, such as a connecting element made of a flexible strip, chain, etc. The guide element can also be a rigid element having a predefined shape, according to one variant.

[0033] According to a particular variant, the upper part comprises a pair of support masts, each support mast having on a lower end a point for fixing said guide element, and being connected to said corresponding pivot point at said lower end, and having at an upper end a means for connection to the user's trunk

[0034] Thus, the upper part is made up of particularly simple elements, mainly allowing the compensation moment of force to be applied to the user's trunk. In particular, the masts can take the form of rods, tubes, blades or any other suitable elongated element. It is possible to provide support masts adjustable in length, by means of rods inserted and adjustable in tubes forming the lower part of the upper part, so as to make the exoskeleton adaptable to different trunk morphologies. Preferably, the support masts are made of metal, or plastic, or composite material, or any other suitable material.

[0035] More particularly, in the context of a first embodiment, the lower end can be bent so as to form a substantially transverse arm, and the point of attachment of said guide element being located on said substantially transverse arm, the mast being connected to said pivot point at the level of said bend of the lower end.

[0036] According to a variant, the elbow of the lower end comprises a yoke oriented towards the corresponding lower module and receiving an axis forming said pivot point, said connecting rod and said support rod of the lower module being threaded onto said axis. It is understood that the support mast of an upper module can be made from a plurality of parts, in particular at the level of the elbow end.

[0037] In this way, a particularly compact arrangement of the exoskeleton is obtained, with all the rotating moving parts essential to the operation of the exoskeleton pivoting around a single axis. Such a design is also particularly advantageous with regard to the assembly of the exoskeleton, since fixing the parts around said axis constitutes practically the only important step in the assembly of the exoskeleton.

[0038] According to an advantageous variant, the exoskeleton comprises a pelvic belt fixed at the level of said pivot points.

[0039] Such a belt allows the exoskeleton to be held in position on the user, and allows the pivot points to be centered around the anatomical pivot point of the user's trunk, so that the compensation moment is exerted optimally. It is also possible to consider any variant forming a support point at the level of the user's pelvis or buttocks, in order to "center" the exoskeleton around the anatomical pivot point located at the level of the user's hips. Advantageously, such a belt is made of textile material, giving flexibility to the assembly, adjustable in circumference, and can be padded for greater comfort.

[0040] According to one variant, the upper part is formed of two independent upper modules coupled by said guide element.

[0041] An important advantage of such a design, in combination with the flexible nature of the coupling assembly, is to obtain an exoskeleton composed of two substantially symmetrical parts, connected by flexible elements. It is understood that thus, the exoskeleton adapts perfectly in width to different user morphologies, without requiring adjustment, the connecting and guiding elements naturally adapting to the width due to their flexible nature. In such a variant, the two halves of the exoskeleton are advantageously, but not imperatively, connected by other flexible elements such as a pelvic belt and / or a trunk harness for better positioning of the exoskeleton on the user.Finally, a two-module design of the upper part improves the torsional behavior of the exoskeleton, the user thus feeling no discomfort from the exoskeleton during his twisting movements of the trunk, the left and right halves not being rigidly connected to each other.

[0042] Furthermore, such an arrangement allows the exoskeleton to be designed in the form of two parts, right and left, which are generally elongated. The exoskeleton is thus made mainly from four modules, each preferably formed from elongated elements, which results in a very small footprint when the exoskeleton is stored or transported.

[0043] According to a complementary variant, said upper modules are linked to the user's trunk by means of a harness connecting the independent upper modules, the harness being U-shaped, the branches of which rest on the user's shoulders and are connected in the user's back.

[0044] Such a harness allows the two upper modules to be connected while connecting the upper part of the exoskeleton to the user's trunk, while being space-saving for the user. The harness is advantageously provided with adjustment elements, such as buckles, which allows the exoskeleton to adapt in width to different morphologies. Advantageously, such a harness is made of textile material, giving flexibility to the assembly, and can be padded for greater comfort. Such a harness is particularly advantageous in a design of the upper part involving two upper modules, however it should be noted that such a harness can also be used as part of an upper part made in a single part.

[0045] According to a particular embodiment, each lower module comprising an elastic actuator, and each lower module comprises a support mast connected by an upper end to said pivot point, and comprising at a lower end a means of connection to a lower limb of the user, a lever arm element pivotally mounted on said pivot point by a first end, and a second end of which is connected to the connection element, and said elastic actuator of a lower module is a tensile member, extending between the second end of the lever arm element and the lower end of said support mast of the lower module

[0046] In this way, each lower module is cleverly made up of three simple elements, linked on the one hand to the user's lower limb, and on the other hand to the pivot point. In such a structure, the support mast plays the role of an element that doubles the user's skeleton, the mast substantially following the thigh of the user's lower limb. The support mast is for example a metal, plastic, composite, etc. rod that is substantially non-deformable and rigid, so as not to deform when the elastic actuator is tensioned. It is understood that in such an embodiment, the support masts of the upper part transmit the compensating force moment to the user and are therefore relatively rigid, so as not to deform under the effect of the moments applied to them.

[0047] In such an embodiment, the connecting element is connected to the lever arm elements, which are themselves connected to the elastic actuator. When in an active state, the connecting element is driven by the guide element, consequently driving the lever arm element into rotation, the elastic actuator under tensile stress is stretched and stores elastic energy. It is also understood that in the inactive state, the lever arm elements can pivot freely in counter-phase, like the lower modules relative to the upper part, causing no tensioning of the elastic actuator.

[0048] According to a variant of this embodiment, the elastic member of a lower module is chosen from: an elastic cable, an elastic strap, a helical spring, a gas spring, a hydraulic spring.

[0049] According to a preferred variant, the elastic member is an elastic cable or strap comprising an elastic core, preferably made of rubber, and a protective sheath, preferably made of woven material having a capacity for deformation.

[0050] Thus, it is possible to store potential energy in the form of elastic energy in a particularly simple element, commonly available commercially, inexpensive and which can be easily replaced in the event of wear. Such a cable can, for example, be found under the name of a strap / cable "Sandow".

[0051] According to another particular embodiment, the exoskeleton comprises two elastic actuators, in which each lower module comprises a support mast connected by an upper end to said pivot point, and comprising at a lower end a means of connection to a lower limb of the user, each end of the connecting element directly connects the support mast of a lower module, and in which each pair of lower module support mast - upper module support mast forms an elastic actuator subjected to bending in said working posture.

[0052] According to a particular variant, said support masts of the lower and upper modules are flexible rods made of composite material.

[0053] Thus, this alternative embodiment makes it possible to produce the at least one elastic actuator directly from the support masts of a lower module and an upper module linked by a pivot point. In other words, the support masts play a dual function of structural support element and elastic actuator. It is understood that in such a case, the support masts are elastically deformable, and have a flexural modulus chosen to exert a satisfactory restoring force on the user's trunk. This force generates a compensating moment of force around the user's pelvis. In order to perform this function, the support masts can for example be flexible rods made of composite material such as fiberglass, or any other material making it possible to obtain the desired behavior.

[0054] In other words, the support masts of a lower module and an upper module together form an elastic actuator subjected to bending, like a leaf spring.

[0055] The role played by the coupling assembly is here identical to that played in the embodiment presented further upstream, the free pivoting in counter-phase in a walking posture “separating” the elastic actuator into two parts (connected by the pivot point), leaving the latter substantially relaxed. The driving of the connecting element by the guide element in a working posture “locks” the support masts, which are found substantially aligned, and form an elastic actuator behaving as a single part, that is to say like a leaf spring type spring.

[0056] It is understood that in such an alternative embodiment, the coupling assembly is only slightly modified, with regard to its attachment points on the lower modules, the operating principle however not being changed. Only the elastic actuator is made in a different and particularly clever way, due to the dual function of the support masts. Such an embodiment also has significant advantages in terms of simplicity of design, assembly, and in terms of cost reduction.

[0057] According to an advantageous variant, the exoskeleton further comprises a disengaging device, configured to couple / decouple a lower module from the mechanical coupling assembly.

[0058] With such a device, it is possible to completely deactivate the exoskeleton when desired by the user. In such a state, the user can adopt postures such as sitting without being hindered in his movements.

[0059] According to a particular embodiment, said disengaging device comprises a connecting rod arranged to pivot on said lower module, said connecting rod being connected to the connecting element, and a release latch, making it possible to block or unlock the pivoting of said connecting rod relative to the lower module, so as to couple or decouple said mechanical coupling assembly from said lower module.

[0060] This results in a space-saving clutch release device, cleverly integrated into the lower module.

[0061] In the first alternative embodiment involving a lever arm on the lower module, the connecting rod is advantageously arranged to pivot on the lever arm. In this case, the clutch release device can be pre-mounted on the lever arm element, which has the effect of not increasing the complexity of mounting the exoskeleton as a whole.

[0062] In the second alternative embodiment involving an elastic actuator formed by the support masts, the link can be pivotally arranged on the upper end of the support mast of the lower module, so as to project transversely from said mast, and can be locked in a projecting position in the active state, in a working posture.

[0063] According to another embodiment distinct from the aforementioned embodiments, the guide element is compressible, and forms an elastic actuator stressed in compression in said working posture.

[0064] In such an embodiment, it is the guide element which plays a dual role of guiding the connecting element and of elastic actuator, making it possible to simplify the exoskeleton and reduce manufacturing costs. BRIEF DESCRIPTION OF THE FIGURES

[0065] Other advantages, aims and particular characteristics of the present invention will emerge from the following non-limiting description of at least one particular embodiment of the devices and methods which are the subject of the present invention, with reference to the appended drawings, in which: [ Fig. 1] is a schematic perspective view of a first embodiment of the exoskeleton, worn by a user, the latter being in an inactive position, the exoskeleton providing no assistance, [ Fig.2 ] is a schematic perspective view of the exoskeleton of the [ Fig. 1 ], worn by a user, the latter being in a working position, the exoskeleton providing assistance, being in an “active” state [ Fig.3 ] is a schematic perspective view of the exoskeleton of the [ Fig. 1 ], worn by a user, the latter being in a walking position, the exoskeleton providing no assistance, being in an “inactive” state, [ Fig.4 ] is a schematic view of the left modules and the right modules side by side, in a sagittal plane of the exoskeleton, in an active state on representation (a) and in an inactive state on representation (b), [ Fig.5] is a schematic view of the right side of the exoskeleton, with the coupling assembly partially shown, [ Fig.6 ] is a schematic rear view of the exoskeleton, in an inactive state in representations (a)-(c), the user being in a walking posture, and in an inactive state in representations (d)-(f), the user being in a working posture, [ Fig.7 ] is a detailed perspective view of the right side of the exoskeleton, [ Fig.8 ] is a side detail view of the right side of the exoskeleton, [ Fig.9 ] is a detailed side view of the right side of the exoskeleton, in a section showing the release device [ Fig. 10 ] is a detailed perspective view of the lever arm element, some of which has been masked to reveal the clutch release device. Fig. 11] is a schematic perspective view of a second embodiment of the exoskeleton, worn by a user, the latter being in an inactive position, the exoskeleton providing no assistance, [ Fig. 12 ] is a schematic perspective view of the exoskeleton of the [ Fig. 11 ], worn by a user, the latter being in a working position, the exoskeleton providing assistance, being in an “active” state [ Fig. 13 ] is a schematic perspective view of the exoskeleton of the [ Fig. 11 ], worn by a user, the latter being in a walking position, the exoskeleton providing no assistance, being in an “inactive” state, DETAILED DESCRIPTION OF THE INVENTION

[0066] This description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

[0067] Please note, from now on, that the figures are not to scale. Example of a first particular embodiment

[0068] There [ Fig. 1 ] represents a user wearing a trunk exoskeleton 100 according to a first embodiment, in a resting state, in which the exoskeleton is in an “inactive” state and does not provide any assistance to the user.

[0069] The trunk exoskeleton 100 is substantially symmetrical with respect to the sagittal plane of the user (corresponding to a sagittal plane of the exoskeleton 100), and has a left part comprising an upper module 200 and a lower module 210, and a right part comprising an upper module 300 and a lower module 310. The upper modules are connected to the trunk 401 of the user, while the lower modules are respectively connected to a lower limb 402, respectively 403, of the user. The upper modules 200 and 300 form an upper part following generally the same orientation, namely that of the trunk 401, and can also be envisaged in a single-piece design.

[0070] For each left and right part, the upper modules 200, respectively 300, are connected to the lower modules 210, respectively 310, by a pivot connection around a pivot point 213, respectively 313, located substantially at the level of the user's hips. In other words, the pivot points 213 and 313 of the left and right part are located on a transverse axis of the user, corresponding to the axis around which the trunk 401 pivots when the user tilts the latter.

[0071] In addition, the right and left parts of the exoskeleton are connected to each other by means of a transverse connecting element, such as a pelvic belt described below, so as to center the exoskeleton at the anatomical pivot point of the trunk 401 with the lower limbs 402 and 403.

[0072] The exoskeleton 100 is configured to provide assistance to the user when the user tilts his or her trunk 401 forward, by providing a compensating force moment directed against the forward tilting movement, said moment being exerted on the user's trunk, around the pivot points 213 and 313.

[0073] The kinematics described above makes it possible to define several relative positions between the modules of the exoskeleton 100.

[0074] First of all, the upper modules 200 and 300 follow the movements of the user's trunk 401, and are thus at all times substantially parallel, and do not form an angle between them in a sagittal plane of the exoskeleton 100.

[0075] The lower modules 210 and 310 are respectively connected to a lower limb 402, 403 of the user. Thus, the lower modules 210 and 310 can not only form an angle with the trunk 401, but also form an angle between them, in a sagittal plane of the exoskeleton.

[0076] There [ Fig.2 ] illustrates a position of the user in which the lower modules 210 and 310 form substantially the same angle with the trunk 401, in a sagittal plane. This position corresponds to a position in which the user lifts an object from the ground, for example, and in which assistance is provided.

[0077] It is noted here that the concept of "substantially the same angle" covers angles between the lower modules and the trunk that are even slightly different. In other words, there is a tolerance on the working posture, a shift between the lower modules being tolerated even for optimal use of the exoskeleton. Similarly, the concept of counter-phase includes a tolerance range, which may be more or less significant, in which the exoskeleton provides no, or very little, assistance. Moreover, in any event, the exoskeleton is functional in all positions that are not positions characteristic of the working or walking posture, although assistance may be less optimal.

[0078] There [ Fig.3] illustrates a position of the user in which the lower modules 210 and 310 form opposite angles with the trunk 401, in a sagittal plane. This position corresponds to a position in which the user walks, and in which no assistance is provided. Such a position also corresponds to a situation in which the lower modules 210 and 310 pivot in counter-phase, according to a pendulum movement or according to an alternating rocking movement.

[0079] There figure 4 schematically represents the left modules and the right modules side by side, in a sagittal plane of the exoskeleton 100. In representation (a), corresponding to the position of the figure 2, the upper 200 and lower 210 modules on the left side, and the upper 300 and lower 310 modules on the right side, form substantially the same angle α between them. The representation (b) corresponds to an instantaneous view of a relative pivoting in counter-phase of the upper 200 and lower 210 modules, and of the upper 300 and lower 310 modules. Such a pivoting in counter-phase (illustrated by the double arrows in bold) corresponds to a walking situation of the user, when the lower limbs 402 and 403 tilt in counter-phase around the trunk 401 of the user, as illustrated in the figure 3 . According to another point of view, this state can be defined by the fact that the upper 300 and lower 310 modules on the right side form an obtuse oriented angle β between them, and the upper 200 and lower 210 modules on the left side form an obtuse oriented angle - βbetween them. In other words, the oriented angles formed are opposite, that is, of the same module but opposite sign. During the pivoting movement, the value of the angle varies, but remains substantially identical for the right and left modules, the sign alternating. It is worth noting that, generally, the upper modules are substantially vertical when the lower modules pivot in counter-phase, corresponding to the user's natural walking position.

[0080] In summary, in the position of representation (a), corresponding to an active state of the exoskeleton, a moment of compensatory force M compis applied to the upper modules, while in the (dynamic) position of representation (b), corresponding to an inactive state of the exoskeleton, substantially no moment of force is exerted on the upper modules. Of course, when the lower and upper modules are substantially aligned, i.e. when the user is not walking, but also not bending down, the exoskeleton is also inactive.

[0081] This operation of the exoskeleton 100 is obtained by the fact that each lower module 210 and 310 comprises a lever arm element 211, respectively 311, and an elastic member 212, respectively 312, as well as by the fact that the exoskeleton 100 comprises a mechanical coupling element 110, connecting the lower and upper, right and left modules.

[0082] Subsequently, reference will be made to the upper right 300 and lower right 310 modules, illustrated in [ Fig.5], it being understood that the same observations apply to the upper left 200 and lower left 210 modules.

[0083] More specifically, the lever arm element 311 is connected to the lower module 310 by a pivot connection around the pivot point 313, so that it can pivot freely relative to the lower module 310.

[0084] In particular, the lower module 310 comprises a support structure in the form of a support rod, forming a support mast, connected by an upper end to the pivot point 313, and comprising at a lower end a means of connection to the lower limb 403 of the user,

[0085] In particular, the lever arm element 311 is a connecting rod having two ends, fixed to the pivot point 313 by a first end. For example, the first end of the connecting rod may comprise a yoke, in which the support rod of the lower module 310 is placed.

[0086] In this embodiment, the elastic actuator is an elastic member 312 extending between a lower end to which the user's lower limb is connected, and the connecting rod forming the lever arm element 311, in particular at a second end of said connecting rod.

[0087] It is understood from this arrangement that when the lever arm element 311 pivots away from the lower limb 403 of the user, the elastic member is tensioned. In this way, in the active state of the exoskeleton, thanks to an elastic restoring force, a compensating moment of force around the pivot point 313 is exerted. This compensating moment of force tends to pivot the lever arm element towards the lower limb 403, which, for reasons which will be seen below, tends to provide assistance to the user who tilts his trunk 401 forward.

[0088] The right upper module 300 is, for example, composed of a support rod 301 forming a support mast, extending along the user's trunk, which has a bent lower end. The bent lower end forms a substantially transverse arm, here also forming a lever arm, on which a force can be exerted causing a moment tending to straighten the user when the exoskeleton 100 is in use. The support rod 301 is connected to the pivot point 313 at the elbow of the lower end, and comprises at an upper end a means of connection to the user's trunk 401. For example, the lower end comprises a yoke oriented towards the corresponding lower module 310, which accommodates an axis forming the pivot point 313, the connecting rod forming the lever arm 311 and the support rod of the lower module 310 being threaded onto said axis.

[0089] It is understood that by this arrangement, the upper module 300 and the lower module 310 can pivot freely relative to each other around the pivot point 313, and that the lever arm element 311 can pivot freely around this same point, relative to the two modules (it being understood that the pivoting away from the lower member 403 is limited by the elastic member 132)

[0090] The behavior of the exoskeleton 100 exposed further upstream is largely obtained by the presence of the mechanical coupling assembly 110, which links the lower modules 210 and 310 together, and also links them to the upper modules 200 and 300.

[0091] In particular, the mechanical connection between the lower modules 210 and 310 is achieved by means of an elongated, flexible connecting element 111, substantially without elastic deformation capacity, which connects the ends of the lever arm elements 211 and 311, which are opposite the pivot points 213 and 313. Such a connecting element 111 is for example a steel cable, of the “Bowden” type.

[0092] Thus, when traction is exerted on the connecting element 111, the lever arm elements 211 and 311 tend to pivot and tension the elastic members 212 and 312. It is understood that the further the attachment point of the connecting element 111 is from the pivot points 213 and 313, the longer the lever arm, and the more the elastic members 212 and 312 can be tensioned. In turn, this means that with equal restoring force exerted by the elastic member 212 and 312, less traction on the connecting element 111 is necessary, the greater the lever arm, which results in an increased lifespan of the exoskeleton.

[0093] The connection of the lower modules 210 and 310 to the upper modules 200 and 300 is carried out by means of a guide element 112 of the connecting element 111. The guide element 112 aims to couple the two upper modules to the two lower modules. In this way, the mechanical coupling assembly 110 couples both the lower modules to each other via the connecting element 111, and the lower modules to the upper modules via the guide element 112. In other words, the connecting element 111 and the guide element 112 each connect the lower modules, respectively upper, but are not directly connected to each other. However, the guide element 112 constrains the connecting element 111 in its movements, forcing it to move longitudinally in the guide element 112.

[0094] Thus, the combination of the mechanical connection of the lower modules to each other by the connecting element 111 and the guiding of the latter in the guiding element 112 limits the free rotation of the lever arm elements 211 and 311. Indeed, the displacement of the left lever arm element 211 causes the displacement of the right lever arm element 311, and vice versa. Thus, the lever arm elements 211 and 311 can pivot in counter-phase freely. In particular, when the connecting element 111 is a cable, of constant length due to its lack of elastic deformation capacity, the distance separating the two ends of the lever arm element 211 and 311 along the path of the cable remains identical for mechanical reasons. The guiding element 112 ensures that the connecting element 111 generally follows the same path in all circumstances, and avoids any uncontrolled deformation of the latter.To this end, it is useful to specify that the guide element 112 has a certain incompressibility, so as not to be deformed under the action of the connecting element 111 which passes through it.

[0095] When the connecting element 111 is a cable, the guiding element 112 may be a sheath of a diameter suitable for receiving said cable. Such a sheath is then relatively flexible and has sufficient flexibility to allow its arrangement on the exoskeleton, while being incompressible. Such sheaths are known in the art. The sheath is then fixed by a first end to the upper left module 200, and by a second end to the upper right module 300. The sheath being thus integral with the upper modules 200 and 300, any rotation of the latter relative to the lower modules 210 and 310 also causes a displacement of the cable, via the sheath. The cable being of constant length, the latter pulls on the lever arm elements 211 and 311, which in turn tend to tension the elastic members 212 and 312.In this way, when the upper modules 200 and 300 form substantially the same non-zero angle, of identical sign, with respect to the lower modules 210 and 310, the lever arm elements 211 and 311 are locked in rotation with respect to the upper modules 200 and 300. The elastic members 212 and 312 are deformed and put under tension, causing the application of a compensating moment of force on the upper modules 200 and 300.

[0096] In particular, the sheath is attached to the upper modules 200 and 300 at the lower end, and the cable and sheath pass behind the user's back so as not to hinder their movements.

[0097] An advantage of providing a guide element 112 in the form of a sheath is to be able to guide the cable in such a way as not to encumber the user, in addition to improving wear resistance, safety, etc. It is also possible to imagine a connecting element 111 which is different from a cable, such as a strap, a chain, or even a combination of flexible elements and rigid elements.

[0098] Alternatively, it is also possible to imagine a guide element 112 other than a sheath, such as simply two eyelets placed respectively on the lower ends of the upper modules 200 and 300, in which the cable passes, which would then need to be tensioned. The cable is thus linked to the upper modules 200 and 300, but is not protected and is not guided behind the user's back. However, such a solution only illustrates other possible variants, but does not have the advantages of a solution comprising a flexible guide element.

[0099] In view of the above, it is understood that the right part formed by the modules 300 and 310 and the left part formed by the modules 200 and 210 are linked by the coupling assembly 110, which is flexible. Thus, the exoskeleton 100 does not have a predefined width and can simply adapt to the morphology of the user who wears it.

[0100] As a summary, the [ Fig.6 ] schematically illustrates the effects described above. Representations (a) to (c) illustrate a situation in which the user is walking, while representations (d) to (f) represent a situation in which the user is leaning forward at a greater or lesser angle. The exoskeleton is shown from the back, with the cable forming the connecting element 111 being shown visible in dotted lines through the sheath forming the guiding element 112.

[0101] In representation (a), the lower modules 210 and 310 pivot in counter-phase, schematically this can be summarized by an “upward” movement of the lever arm element of a first lower module, and a “downward” movement of the lever arm element of the other module. The connecting element 111 moves in the sheath accordingly, without changing its length. In representation (b), the lower modules 210 and 310 are in the same angular position, before continuing their pivoting in counter-phase as illustrated in representation (c), which is the mirror of representation (a). During this movement, the elastic members 212 and 312 are not deformed and are not put under tension, the lever arm elements 211 and 311 as well as the elastic members 212 and 312 following the movement of the lower limbs.

[0102] In representation (d), the user is standing, at rest, the lower and upper modules are aligned. The elastic members 212 and 312 are not stretched. In representation (e), the user's trunk 401 is leaning slightly forward, so that the lower and upper modules form substantially the same angle. α 1. The elastic members 212 and 312 are then slightly deformed (they lengthen by a distance approximately equal to the sine of the angle α 1 multiplied by the length of a lever arm element, in the preferred embodiment of this embodiment. Other behaviors can be obtained by winding the connecting element 11 around a cam, pulley, etc.), thus being under tension, and applying a compensating moment of force M comp 1 on the upper modules. In representation (f), the user leans a little more, at an angle α 2 , and a moment of compensatory strength M comp 2 on the upper modules is applied. It is noted that the elastic members 212 and 312 are stretched because the lower members are immobile, but that the lever arm elements 211 and 311 are pulled by the mechanical coupling assembly 110, which is linked to the upper modules 200 and 300.

[0103] According to a preferred variant, the lever arm elements 211 and 311 take the form of connecting rods formed from two plates arranged opposite each other, as can be seen in the [ Fig.7 ], and include a device for disengaging the assistance of the exoskeleton, produced in the following manner.

[0104] Between the two plates is pivotally arranged a connecting rod 214, respectively 314. Such connecting rods 214 and 314 can also be formed of two plates arranged opposite each other, and connected by holding pins. We refer again to the right side, the left side being substantially symmetrical to the right side.

[0105] As can be seen on the figures 9 And 10 , on which one of the two plates of the lever arm element 311 has been removed, the connecting rod 314 pivots around an axis 315, distinct from the pivot 313.

[0106] The connecting rod 314 is connected to the mechanical coupling assembly 110, more precisely to the connecting element 111 at a fixing point 317. The connecting rod 314 can be locked or unlocked in rotation by means of a release latch 316.

[0107] The clutch release latch 316 may for example take the form of a crank 3161 pivoting on the lever arm element 311, the rotation of which causes the translation of a locking pin 3162 by means of a connecting rod 3163, the locking pin 3162 being slidably guided in a groove of the lever arm element 311. The rod 314 has one end having a finger 3141 blocked by the locking pin 3162 in a coupled state of the rod 314 and the lever arm element 311. When the locking pin 3162 enters into translation, by the actuation of the crank 3161, preferably having a lever 3164 actuable by the user, the locking pin 3162 forces a slight rotation of the rod 314 by passing over the finger 3141, the link 314 and the lever arm element 311 then being in a decoupled state.The connecting rod 314 can then pivot freely on the lever arm element 311, and the mechanical coupling assembly 110 is then no longer coupled to the lever arm element. In this way, the elastic members 212 and 312 are not stressed, regardless of the movement of the user, the exoskeleton 100 thus being inactivated.

[0108] Advantageously, one or more springs are arranged on the lever arm element so as to be compressed, or stretched, depending on the type of spring, when the connecting rod 314 is locked in rotation, thus causing a slight rotation of the connecting rod 314 when it is unlocked, so as to place the latter in an unlocked position distinct from the locking position.

[0109] In order to easily move the connecting rod 314 from the unlocked position to the locked position, it is possible to provide a strap connected to the connecting rod 314, on which the user can pull, locking the release latch 316.

[0110] According to a particular embodiment, the upper parts 200 and 300 are connected to the user by means of a harness connecting the right 300 and left 200 upper modules. Such a harness may for example be U-shaped, with branches resting on the shoulders of the user, connected in the back of the user. In this way, the harness rests on the shoulders and the upper part of the back of the user. However, this harness is not intended to transmit significant forces, the user working against the upper modules, and vice versa, the upper modules thus being pressed against the trunk 401, without requiring any particular connection with the trunk.In other words, it would be sufficient for the upper ends of the upper modules 200 and 300 to rest on the user's trunk 401, for example by means of pads, however a harness as described above allows better support, without risk of displacement of the exoskeleton, providing better security of the system. Of course, the harness can be padded for more comfort. Also, it is possible to provide a strap with a closing buckle, connecting the two upper modules from the front, as can be seen in the . figures 1 to 3 .

[0111] Similarly, at the lower ends of the lower modules 210 and 310, support pads and / or armbands or straps for connecting to the lower limbs 402 and 403 may be provided, so that the lower modules 210 and 310 can follow the movement of the lower limbs 402 and 403.

[0112] The transverse connecting element mentioned above advantageously takes the form of a pelvic belt connected to the upper and lower modules at the pivot points 213 and 313. More precisely, the pelvic belt is connected to said modules by pivot links coaxial with the pivot points 213 and 313, so as to follow the movements of the user, thus increasing the comfort of use. Such a belt can take the form of a strap, padded or not, provided with one or more closure and / or adjustment buckles, in order to adapt the exoskeleton 100 to different user morphologies, in particular with regard to waist size. Any other connecting element, other than a pelvic belt, may be considered, provided that it connects the right and left parts of the exoskeleton at the pivot points, and that it allows at least partial support of the exoskeleton at the user's waist.

[0113] The use of textile straps, particularly for the harness and the pelvic belt, gives the exoskeleton 100 great flexibility, both in trunk torsion and lateral flexion.

[0114] The exoskeleton 100 advantageously has a means for adjusting the starting angle of the assistance. Such an adjustment means can be formed at the lower end of the upper modules 200 and 300. As can be seen in the figures, the end to which the connecting element 111 is fixed can take the form of an end piece in which the guide element 112 is housed, comprising a threaded tapping, the end piece being screwed onto a threaded end of the rod forming an upper module. In this way, the axial position of the end piece can be varied, and by screwing / unscrewing the end piece more or less. This adjustment has the effect of varying the distance between the outlet of the guide element 112 and the axis 317 (respectively 217 for the other side). Since the guide element 112 is substantially incompressible, the connecting element 111 is tensioned when the distance between the output of the guide element 112 and the axis 317 increases.

[0115] Thus, when the tip is positioned so as to increase the distance between the output of the guide element 112 and the axis 317, i.e. to tighten the connecting element 111, then the angle from which the assistance is triggered approaches zero, i.e. the assistance is triggered even during movements of small amplitude. On the contrary, when the tip is positioned so as to minimize the distance between the output of the guide element 112 and the axis 317, i.e. to loosen the connecting element 111, then the angle from which the assistance is triggered moves away from zero, i.e. the assistance is triggered only during movements of relatively large amplitude. In this way, an adjustment of the starting angle of the assistance is obtained.

[0116] Finally, a means for adjusting the height of the exoskeleton 100 may be provided. Such an adjustment means may for example be included at the level of the upper modules 200 and 300. Instead of a rod forming the structure of the latter, it is possible to provide an arrangement of rods sliding in tubes, making it possible to adjust the height of the connection point of the exoskeleton with the user's trunk.

[0117] It is not necessarily useful to provide a lock for this adjustment means, because it may be advantageous to allow the rods to slide freely when using the exoskeleton, thus compensating for deformations of the user's trunk, in particular if the latter bends his back for example. It is recalled that advantageously the exoskeleton 100 is linked to the user's trunk by means of a harness, which therefore reduces any risk of unforeseen shifting of the exoskeleton on the trunk, making it possible to dispense with any locking member. Of course, such an optional member may nevertheless be provided. Example of a second particular embodiment

[0118] There [ Fig. 11 ] depicts a user wearing a trunk exoskeleton 500 according to a second embodiment, in a resting state, in which the exoskeleton is in an “inactive” state and provides no assistance to the user.

[0119] The exoskeleton 500 of this second embodiment has substantially the same structure as the exoskeleton 100 of the first embodiment, which is why only the differences will be explained subsequently. In particular, the operation and the structure of the coupling assembly are substantially identical. The same references designate the common or substantially identical elements.

[0120] The upper modules 200 and 300 do not differ structurally from those of the exoskeleton 100, however the rods forming support masts have a flexibility giving them leaf spring type spring properties, unlike the rods of the exoskeleton 100, which are substantially rigid.

[0121] The lower modules 210 and 310 are made up for the most part of rods forming support masts, as for the exoskeleton 100, these rods also having leaf spring type spring properties.

[0122] For example, the rods are formed from a composite material such as fiberglass.

[0123] The lower modules 210 and 310 do not comprise a lever arm element, but an arm 711, respectively 811, projecting substantially transversely, at the end of which is fixed one end of the connecting element 111, the connecting element thus directly connects the two lower modules. The projecting arm can be formed directly on the rod, or on a tip fixed on the rod. When the exoskeleton comprises a disengaging device, the projecting arm can be locked in its projecting position, or disengaged so as to be able to pivot freely. In other words, the projecting arm can be produced in the form of a connecting rod arranged to pivot on the lower module, according to an embodiment produced mutatis mutandis from the disengaging device of the first embodiment described upstream.

[0124] The support masts of the upper modules 200 and 300 are connected to the pivot points at a lower end, but are not directly bent here, since no lever arm is required. Only a transverse arm, formed for example on a fixing clevis at the pivot point, serves here as a fixing point for the guide element 112 at the lower end.

[0125] THE figures 12 And 13 respectively illustrate the user in a working and walking posture.

[0126] It is visible at the [ Fig. 12] that, in this second embodiment, the rods of the upper modules 200 and 300 and lower 210 and 310 are bent and under tension, and act as leaf spring type springs. More precisely, each pair of upper module rod - lower module rod acts as a leaf spring type spring, the rods of such a pair being locked in rotation and behave like a single long flexible rod. In other words, this embodiment comprises two elastic actuators 712 and 812 formed by the support masts of the upper and lower modules.

[0127] On the [ Fig. 13 ], it is visible that thanks to the casting assembly, the lower modules 210 and 310 can pivot freely in counter-phase, the rods of a pair of rods then behaving like two articulated elements, without being bent, the exoskeleton then providing substantially no assistance.

[0128] Furthermore, all additional elements such as the pelvic belt, the harness or any other element described above can be advantageously implemented on the exoskeleton 500.

[0129] It therefore appears very clearly that within the framework of the present invention, the coupling assembly retains substantially the same structure and the same operation regardless of the type of elastic actuator chosen, and regardless of its arrangement. The preferred embodiments described above present two alternative embodiments of the invention, with two different types of structure and arrangement of actuators, it being understood that any other actuator solution can be envisaged and is covered by the present invention.

Claims

1. A trunk exoskeleton (100, 500) including: • an upper part (200, 300) capable of being linked to the trunk (401) of a user of the exoskeleton, • a pair of lower modules (210, 310) each capable of being linked to a lower limb (402, 403) of the user, each lower module being connected to the upper part by a separate pivot point (213, 313) located at the user's hips, • at least one elastic actuator (212, 312, 712, 812) configured to exert, when turned on, a compensating force moment on the user's trunk, • a mechanical coupling assembly (110) configured to: • in a working posture of the user, cause the at least one elastic actuator to be turned on when the lower modules substantially form a same non-zero angle with the upper part, the exoskeleton then providing assistance, and • in a walking posture of the user, allow free counter-phase pivoting of the lower modules, without the exoskeleton providing assistance, characterized in that the coupling assembly includes: • a linking element (111) coupling the lower modules together, • a guide element (112) for the linking element, attached to the upper part, coupling the lower modules to the upper part via the linking element, the linking element and the guide element being flexible.

2. The exoskeleton (100, 500) according to claim 1, wherein said flexible linking element (111) is an elongate element with substantially no elastic deformation capacity, and wherein said flexible guide element (112) is a substantially incompressible elongate element.

3. The exoskeleton (100, 500) according to claim 2, wherein said flexible linking element (111) is a cable, and wherein said flexible guide element (112) is a sheath with a diameter adapted to accommodate said cable.

4. The exoskeleton (100, 500) according to any one of claims 1 to 3, wherein the upper part (200, 300) comprises a pair of support posts, each support post including on a lower end an attachment point for said guide element (112), and being connected to said corresponding pivot point (213, 313) at said lower end, and including at an upper end a means of linking to the trunk of the user5. The exoskeleton (100, 500) according to any one of claims 1 to 4, wherein the exoskeleton further includes a pelvic girdle attached at said pivot points (213, 313).

6. The exoskeleton (100, 500) according to any one of claims 1 to 5, wherein the upper part is formed of two independent upper modules (200, 300) coupled by said guide element (112).

7. The exoskeleton (100, 500) according to claim 6, wherein said upper modules (200, 300) are linked to the trunk (401) of the user by means of a harness connecting the independent upper modules, the harness being U-shaped, the arms of which rest on the shoulders of the user and are connected in the back of the user.

8. The exoskeleton (100) according to any one of claims 1 to 7, each lower module (210, 310) including an elastic actuator (212, 312), and wherein each lower module comprises • a support post connected by an upper end to said pivot point (213, 313), and including at a lower end a means of connecting to a lower limb of the user, • a lever arm element (211, 311) pivotably mounted to said pivot point by a first end, and a second end of which is connected to the linking element (111), and said elastic actuator of a lower module being a tensionally loaded member, extending between the second end of the lever arm element and the lower end of said support post of the lower module.

9. The exoskeleton (100) according to claim 8, wherein the elastic member (212, 312) of a lower module is one selected from: an elastic cable, an elastic strap, a coil spring, a gas spring, a hydraulic spring.

10. The exoskeleton (500) according to any one of claims 1 to 7 and claim 4, comprising two elastic actuators (712, 812), wherein • each lower module (210, 310) comprises a support post connected by an upper end to said pivot point, and including at a lower end a means of connecting to a lower limb of the user, • each end of the linking element (111) directly connects the support post of a lower module, and wherein each lower module support post - upper module support post pair forms an elastic actuator flexurally loaded in said working posture.

11. The exoskeleton (500) according to claim 10, wherein said support posts of the lower and upper modules are flexible rods of composite material.

12. The exoskeleton (100, 500) according to any one of claims 1 to 11, further comprising at least one disengagement device, configured to couple / decouple a lower module (210, 310) of the mechanical coupling assembly (110).

13. The exoskeleton (100, 500) according to claim 12, wherein said disengagement device includes: • a connecting rod (214, 314) pivotably arranged on said lower module, said connecting rod being connected to the linking element, and • a disengagement latch (216, 316), for blocking or unblocking pivoting of said connecting rod with respect to the lower module (210, 310), so as to couple or decouple said mechanical coupling assembly (110) of said lower module.

14. The exoskeleton according to claim 1, wherein the guide element (112) is compressible, and forms an elastic actuator compressively loaded in said working posture.