Exoskeleton with elastic elements

Abstract

The present invention relates to an exoskeleton (100) comprising: an arm (110) including means for attaching an upper limb; a load-bearing structure (140) including a fulcrum (141); a compensation element (130) fixed to the arm by a first pivot (131), extending between the arm and the load-bearing structure and applying a compensation force moment to the arm by deformation of an elastic element; a force transmission element (150) extending between a lower point of the compensation element and the "rear end" of the arm, the elastic element and the force transmission element being configured to be continuously tensioned during use of the exoskeleton and the moment varying with the inclination of the arm, the transmission element being fixed to the arm by a second pivot (151), the first pivot being located between the second pivot and the front end of the arm.

Description

[Technical Field]

[0001] The field of the invention is that of exoskeletons, mechanical structures that partially duplicate the human skeleton to assist in the performance of tasks or activities such as lifting and carrying loads.

[0002] The term "load" is understood in this document to refer to the weight supported by the user, i.e. the weight or force applied by one or more objects being handled, possibly plus the weight of the user's own upper limbs.

[0003] More specifically, the present invention relates to an exoskeleton comprising elastic elements that generate load-compensating force moments to ease the load on the wearer of said exoskeleton when performing a task or activity.

[0004] In particular, the present invention finds application in the medical, military and physical / manual work fields, where it can in particular prevent the occurrence of musculoskeletal disorders. [Background technology]

[0005] Exoskeleton techniques are known from the prior art that can relieve the wearer's load, especially when performing painful and repetitive tasks that are involved in the development of musculoskeletal disorders.

[0006] Exoskeleton techniques for medical and military purposes, aimed at restoring the physical performance of physically debilitated individuals or improving the physical performance of able-bodied individuals, are also known from the prior art.

[0007] Therefore, exoskeleton solutions using various mechanical means are known, in particular robotic means with actuator cylinders.

[0008] The drawbacks of such robotic systems are, in particular, their large mass, their high acquisition and maintenance costs, and the need for access to an energy source, e.g., electrical or hydraulic, which is generally heavy and difficult to handle when embedded in an exoskeleton, and which generally has low autonomy.

[0009] Purely mechanical systems are also known, ie systems that do not include electromechanical or hydromechanical actuators and do not require an on-board energy source.

[0010] Many such systems are based in particular on the use of cables, pulleys or rods arranged to support the wearer's limbs, said systems being self-powered by storing energy supplied from outside the system in the form of elastic energy, said storage being achieved by deformation of the elastic elements during movement of the wearer's limbs.

[0011] Although such systems can mitigate some of the above-mentioned drawbacks, these known prior art solutions have proven difficult to handle and involve a number of elements that are detrimental to the wearer's freedom of movement and ergonomics.

[0012] Furthermore, these known systems typically withstand significant forces on their core components, requiring significant resizing which increases the mass of the exoskeleton, or requiring relatively frequent part replacement if mass optimization is desired.

[0013] None of the current systems address all of these needs simultaneously, i.e., offer a non-motorized, non-robotic exoskeleton that meets the criteria of reduced mass, cost, and size while offering a simple design and long service life. Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention aims to overcome all or some of the above-mentioned drawbacks of the prior art. [Means for solving the problem]

[0015] To this end, the present invention relates to an exoskeleton adapted, in use, to assist at least one upper limb of a wearer of said exoskeleton in lifting and carrying a load, said exoskeleton comprising: at least one arm, at one of its ends, called the "front end", comprising at least one means for attaching an upper limb of said wearer; - a load-bearing structure designed to be fixed to said wearer, including at least one fulcrum; at least one compensation element fixed to said arm by a first pivot, extending between said arm and said load-bearing structure to which said element is fixed, and which applies a compensation force moment to said arm by deformation of at least one elastic element; a force transmission element extending between the lower point of the compensation member and the end of the arm opposite the front end, called the "rear end" 10. The exoskeleton comprising: - said at least one elastic element and said force transmission element are configured to be continuously tensioned during use of said exoskeleton and said force moment varies with the tilt of said arm; the transmission element is fixed to the arm by a second pivot located at the rear end of the arm, the first pivot being located between the second pivot and the front end of the arm;

[0016] These configurations provide an exoskeleton technique that is completely self-powered by storing energy in elastic elements, thereby reducing mass and size and eliminating the need for an energy storage reservoir.

[0017] The exoskeleton also provides the user with assistance consistent with the applied stresses, i.e., compensatory stresses, or more specifically compensatory force moments, that are relatively large when the user is in a working position, for example handling a load, and relatively small when the user is in a rest position with their arms along their body towards their feet.

[0018] Because the exoskeleton extends between the user's waist and upper limbs, the arms of the exoskeleton are positioned below the upper limbs during use. Therefore, the arms of the exoskeleton are only stressed when bending, rather than when bending and twisting as in known exoskeletons of the prior art, which allows for a longer lifespan and smaller dimensions. More specifically, sizing the arms so that they are stressed when bending but not when twisting results in a reduced profile compared to arms that are also stressed when twisting. This further allows for the design of the arms from composite materials, which have the property of being highly resistant to bending but hardly resistant to twisting. This allows for the use of materials including, for example, glass or carbon fiber, resulting in exoskeleton arms with significantly reduced mass compared to known exoskeleton techniques.

[0019] Furthermore, the structure formed by the compensating member, the arm, and the force-transmitting element is self-stressed, i.e., the elements and their components form a structure that is in equilibrium under the action of compressive and tensile stresses. In particular, the force-transmitting element and the elastic element are only subjected to tension, while the compensating member and other components of the arm are subjected to compressive stresses. Since the arm also contains a load application point, which is stressed during bending as described above, the system of self-stressed elements does not form a so-called perfect "tensegrity" system, but comes very close to it. In particular, when no load is present, the mass of the arm is negligible, so the system is in a quasi-tensegrity state. It should be understood that the equilibrium state of the structure fluctuates under the influence of the load, and one or more of the elastic elements allow the equilibrium state to be reached by their variable tension, so that the equilibrium state of the structure is dynamic.

[0020] The presence of a single elastic element allows for the "basic" output behavior of the exoskeleton, where the compensation force felt by the user varies sinusoidally and is felt to be maximum in the so-called "working" position and minimum in the "low" and "high" extreme positions.

[0021] However, an exoskeleton according to the present invention may comprise many more elastic elements, the number of which is theoretically infinite. In practice, it is possible to design a compensation member with multiple elastic elements in series or parallel, thereby obtaining different output behaviors of the exoskeleton. In particular, elastic elements with different elastic constants can be used, which allows further variation of the output behavior.

[0022] Furthermore, the increased elasticity allows the compensation element to be designed in various shapes, in particular curved, so as to follow the lines of the user's body as closely as possible.

[0023] Furthermore, depending on the design of the exoskeleton, the compensation force preferably increases monotonically from the extreme positions to the intermediate position, so that loads that are more difficult for the user to transport or handle are compensated more strongly. This allows the user to feel progressively more supported and to perform smoother gestures. In particular, the force felt by the user follows an approximately sinusoidal shape, resulting in greater compensation at positions near the working position and relatively less compensation at the extreme positions where only moderate correction is required. Furthermore, since the progression of this compensation force as a function of the position of the upper limbs corresponds to the progression of the force applied by the upper limbs to the wearer's shoulders, the exoskeleton compensates for the loads represented by the upper limbs at all their angular positions, thereby constantly easing the load on the wearer of the exoskeleton.

[0024] In certain embodiments of the invention, the arm includes a mechanism for setting the distance between the first pivot and the second pivot.

[0025] These configurations allow to vary the lever arm on which the compensation force acts, and thus the available compensation force moment, thus allowing the user to adapt in a very simple way the output "power" of the exoskeleton depending on the type of task or activity he wants to perform.

[0026] In a particular embodiment of the present invention, the configuration mechanism comprises: - an opening in said first pivot, in which said arm can slide; a setting plate located at one of the ends of the arm, said plate being fixed to a worm screw cooperating with a threaded opening in the pivot; Equipped with.

[0027] These configurations make the setup particularly easy to access and intuitive, allowing a wide range of users to use the exoskeleton without special training in its use, and can be performed by the user alone, without assistance and without the need to remove the exoskeleton, allowing for "in real-time" adaptation of the desired torque according to the exoskeleton's conditions of use.

[0028] In certain embodiments of the invention, the compensation member comprises: - the state of minimum tension occurs when the upper limb is in the first extreme position, so-called "high"; - The maximum tension occurs when the upper limb is in the second extreme position, the so-called "rest" position. The elastic element is provided as follows: The tension of the elastic element causes the retraction of the compensation element, which is in the deployed and maximum retracted state in the high position and in the rest position, respectively.

[0029] With these configurations, the compensation members act in compression on the arms of the exoskeleton, using elastic elements that act in tension, which are simpler than elements that act in compression.

[0030] The exoskeleton's arms are subjected to a force moment that tends to pivot the arms about a point of rotation toward the rest position. The use of a compensating element acting in compression allows for the application of a compensating force (resulting in a compensating moment) between the point of rotation and the point of application of the load. In contrast, many known systems in the prior art, in which compensating elements act in tension, are forced to apply a compensating force opposite the point of application of the load, thereby increasing the length of the exoskeleton's arms and increasing the size of the exoskeleton. The above-described design thus solves a previously unresolved problem: obtaining an exoskeleton with compact arms that do not protrude significantly from the wearer's body, while using elastic tension elements that are lighter, cheaper, and smaller than comparable compression elements.

[0031] In certain embodiments of the invention, the compensation member comprises: - upper bar; and - Lower bar the bars are parallel, the upper end of said lower bar is fixed to the upper plate, the lower end of said upper bar is fixed to the lower plate, The upper and lower bars slide within openings in the upper and lower plates, respectively, and the resilient element extends between the upper and lower plates.

[0032] These configurations allow the exoskeleton according to the present invention to be made using simple, inexpensive, and readily available components on the market.

[0033] Furthermore, these configurations provide a sufficiently stiff and simple design for the compensation member, thus creating kinematic characteristics that allow the compensation device to double in length in the deployed state.

[0034] Furthermore, the design using two parallel bars (or tubes) reduces the number of positions where the cantilevered portion of each bar is large: in practice, these positions are limited to the deployed position or positions close to the deployed position; in the remaining positions, the upper and lower plates reduce the cantilevered length of each bar, thereby significantly limiting the risk of buckling of the bars.

[0035] While known solutions of the prior art provide compensators, often with a single bar or a single tube, that transition beyond the user's upper limbs towards the shoulders, the design proposed by the present invention allows the length of the compensating element to be limited to the distance separating the fulcrum and the first pivot, i.e., the distance separating the user's waist and upper limbs. This distance is covered by two bars, which are guided by plates, which significantly reduces the risk of buckling compared to known prior art. Thus, bars or tubes with significantly reduced dimensions can be used, which allows the exoskeleton to be even lighter compared to known solutions.

[0036] In a particular embodiment of the invention, the at least one elastic element is an elastic cable, which comprises an elastic core, preferably made of rubber, and a protective sheath, preferably made of an elastic woven fabric.

[0037] Due to these configurations, the elastic element is made of a particularly light, inexpensive and readily available element.

[0038] In certain embodiments of the invention, the force-transmitting element comprises an elongate element that is substantially not elastically deformable.

[0039] In a particular embodiment of the invention, the force transmission element comprises two elongate elements extending parallel to each other on each side of the compensation member.

[0040] In this way, the force transmission elements are arranged on each side of the compensation member, making the design of the exoskeleton according to the invention particularly compact.

[0041] In a particular embodiment of the invention, the elongate element is a cable.

[0042] These configurations make the exoskeleton according to the invention particularly lightweight without sacrificing structural performance, and the force transmission elements are only subjected to tension and can be made using cables.

[0043] In a particular embodiment of the invention, the fulcrum is a spherical housing and the compensation member includes a spherical head, thereby forming a ball joint connection.

[0044] These configurations allow the compensation members and arms of the exoskeleton to rotate about any axis in space, preserving freedom of movement for the user's upper limbs.

[0045] In certain embodiments of the invention, the load bearing structure is a pelvic belt adapted to grip the hips and / or waist of the wearer.

[0046] These configurations ensure that the exoskeleton is held in an area of ​​the user's body that can absorb significant stress, thereby contributing to reducing the risk of injury or the occurrence of musculoskeletal disorders.

[0047] It should also be noted that the exoskeleton is held only by the user's waist / buttocks and upper limbs, but particularly the shoulders, and no other means of support, for example by suspenders, are required.

[0048] In a particular embodiment of the invention, the attachment means comprises a longitudinal cushion, the projection of the axis of the cushion and the projection of the axis of the arm onto a so-called "horizontal" plane intersecting at an angle of 0 to 30° when the exoskeleton is in the so-called "working" position.

[0049] With these configurations, the exoskeleton does not present a risk of collision with the user's flanks and underarms, thereby increasing the safety and comfort of using the exoskeleton.

[0050] Thus, the user can perform movements of more than 90° to the left and right in the working position, and the risk of collision between the exoskeleton and the user is reduced by the above-mentioned configuration.

[0051] Other advantages, objects and particular features of the present invention will become apparent from the following non-limiting description, with reference to the accompanying drawings, of at least one particular embodiment of the device and method that is the object of the invention. [Brief explanation of the drawings]

[0052] [Figure 1] FIG. 1 is a schematic perspective view of an exoskeleton according to the present invention worn by a user. [Figure 2] FIG. 2 is a schematic perspective view of the exoskeleton in a so-called "working" position. [Figure 3] FIG. 3 is a schematic perspective view of the exoskeleton in a so-called "rest" position. [Figure 4] FIG. 4 is a schematic perspective view of the separated exoskeleton in the so-called "high" position. [Figure 5] FIG. 5 is a graph of the progression of the compensation force as a function of the angle of inclination of the arm relative to the horizontal. [Figure 6] FIG. 6 shows a top view of the exoskeleton in the so-called "working" position. [Figure 7] FIG. 7 is a perspective view of the exoskeleton in the so-called "working" position, with the user's arms outstretched without the modular arms hitting their sides. DETAILED DESCRIPTION OF THE INVENTION

[0053] The following description is given in a non-limiting manner, and each feature of one embodiment can be advantageously combined with any other feature of any other embodiment.

[0054] Please note that the diagram is not currently to scale.

[0055] The present invention relates to an exoskeleton 100, which is shown in Fig. 1 worn by an individual 200 (hereinafter also referred to as "user" or "wearer"). The exoskeleton 100 generally comprises a right module 101 adapted for off-loading the user's right upper limb 201 and a left module 102 adapted for off-loading the user's left upper limb 202, although for the sake of brevity, it is specified that in the following only one of these two modules will be referred to, namely the left module 102, and also for the sake of brevity, the term "left" will be omitted. It is also specified that the two modules, right module 101 and left module 102, are identical or similar in terms of structure and are symmetrical with respect to the wearer.

[0056] It is also possible to create an exoskeleton 100 with only one module on the right or left side depending on the desired application or the physical characteristics of the user.

[0057] As shown in Figure 1, each module of the exoskeleton is intended to relieve the load on the corresponding upper limb, i.e. to reduce the physical effort provided by the user resulting in muscular activity and therefore in particular lower cardiac activity and respiratory activity, thereby providing the user with less physically tiring activity conditions and maintaining the user's health.

[0058] However, on the other hand, it may also be possible to improve the user's physical performance with a comparable physical effort (compared to activities without the exoskeleton according to the invention), in other words to increase the user's ability to lift, carry or handle loads, i.e. to reduce the weight of the load felt by the user.

[0059] More specifically, the force generated by a load (not shown in FIG. 1) on the exoskeleton corresponds primarily to the weight of said load.

[0060] It is easy to see that this load applies stresses in the form of forces and moments to the exoskeleton, and that the stresses applied by the load tend to act against the stresses due to the user 200. Thus, the primary function of the exoskeleton is to act against the forces applied by the load and to support the stresses due to the user 200.

[0061] 2 shows the left module 102 with the arm 110 in a so-called "working" or "neutral" position, in which the arm 110 is generally horizontal and the left upper limb of the user 200 is also generally horizontal, although there may be a lack of parallelism between the arm 110 and the user's upper limb. "Generally horizontal" is to be understood as an orientation generally parallel to the ground and generally perpendicular to the body of the user 200. Thus, when the user 200 is standing in this characteristic position, the arm 110 and the upper limb are directed forward. This position is called the "working" position, since it corresponds to the position in which the user 200, for example, carries a load with his or her hands or handles tools.

[0062] 3 shows module 102 in a first extreme position, a so-called "rest" or "low" position, in which, when user 200 is standing, the upper limbs of user 200 are generally vertical, i.e., generally perpendicular to the ground and generally parallel to the body of user 200, and pointing downwards. This position is called the "rest" position because it corresponds to a position in which user 200's arms and hands are aligned downwards along the body, making it generally impossible to perform a task or activity.

[0063] However, it should be noted that in this characteristic position, the arm 110 is not strictly vertical, but forms an angle of 0-45° with the arm of the user's upper limb in a plane parallel to the wearer's sagittal plane. However, this position actually corresponds to the extreme position of the arm from a mechanical point of view, with the exoskeleton nearly fully retracted, as shown in FIG. 3.

[0064] 4 shows module 102 in a second, so-called "high" extreme position, in which, when user 200 is standing, the user's 200 upper limbs are generally vertical, i.e., generally perpendicular to the ground and generally parallel to the user's 200 body, and pointing upward. Note that this extreme "high" position is not strictly a vertical position for arm 110, but is a position within an angular range between vertical and approximately 15° forward of this position. This so-called "high" position corresponds to a position in which the user's 200 arms and hands are generally parallel to the user's body and point upward, for example, to reach an object at a height or to use a tool higher than the user.

[0065] As shown in Figure 4, the exoskeleton is not fully deployed in this extreme "high" position, thereby providing assistance to the user even in this extreme position. Furthermore, slight bending of the exoskeleton in this manner causes the exoskeleton to retract, i.e., transition toward a position closer to the neutral position.

[0066] It will therefore be appreciated that the exoskeleton 100 is oriented in use relative to the body of the user 200, which represents a frame of reference that allows the identification of relative positions referred to as "high", "low", "front" and "rear", as well as "upper" and "lower", in the user's standing position, and in particular in the so-called "working" position.

[0067] As shown particularly in Figures 2-4, the modular arms 110 of the exoskeleton 100 include means 120 for attaching the upper limbs 102 of the wearer 200. The exoskeleton arms 110 are thus generally parallel to the upper limbs 102, and more specifically to the arms of said upper limbs, in use. However, there is a lack of parallelism, especially in positions approaching the extreme "rest" and "elevated" positions.

[0068] The compensation member 130, which has a generally elongated shape, is pivotally fixed to the arm 110 via a first simple pivot 131. As shown in particular in Figure 2, the axis of the first pivot 131 is approximately perpendicular to the arm 131 and to the compensation member 130. It should be noted that the reference number 131 hereinafter does not only represent the first pivot from a mechanical point of view, but also the part where the pivot point is located.

[0069] A load bearing structure 140 including a fulcrum 141 supports the compensation member 130 and thus the arm 110 .

[0070] In other words, the compensation member 130 is located between the load bearing structure 140 and the arm 110 .

[0071] Advantageously, the load-bearing structure 140 is a pelvic (or abdominal) belt adapted to grip the wearer's hips and / or waist, depending on how the user wears the exoskeleton 100.

[0072] Advantageously, such a belt is made of woven fabric and preferably comprises at least one closing buckle, which may be adjustable. To increase the possible adjustment range, belts are also conceivable which comprise an adjustment buckle, which is advantageously located opposite the closing buckle.

[0073] In this example, the fulcrum 141 is a support plate 142 fixed on a load bearing structure 140, which comprises a spherical housing.

[0074] The compensation member 130 has at its so-called "low" end, i.e., at the end closest to the load bearing structure 140, a spherical head that is adapted to be inserted into a spherical housing of the support plate 142 to form a ball-joint connection that allows three independent rotational degrees of freedom of the compensation member 130 relative to the load bearing structure 140.

[0075] However, it is possible, and in some combinations even desirable, to have only two, only one, and possibly no rotational degrees of freedom between the compensation member 130 and the load bearing structure 140. In this case, the ball joint connection can be replaced by, for example, a double pivot, a single pivot, or a recessed one.

[0076] The compensation member 130 applies a compensation force moment to the arm 110 that varies with the position of the upper limb 202 and therefore the position of the arm 110 .

[0077] Advantageously, the compensation force moment is generated by deformation of the elastic element 132 of the compensation member 130. It will thus be appreciated that the energy available to the user is stored solely in the elastic element 132 in the form of elastic energy, and that no other energy source is required, thereby providing the exoskeleton with great lightness, compactness and autonomy.

[0078] More specifically, the maximum compensatory force moment is applied when the upper limbs 202 are in the so-called intermediate "working" position, a feature that is particularly advantageous considering that in this position the user 200 requires the greatest assistance from the exoskeleton 100.

[0079] A first, minimum compensatory force moment is applied when the upper limb 202 is in a first extreme position, the so-called "rest" or "low" position.

[0080] A second, minimum compensatory force moment is applied when the upper limb 202 is in a second extreme position, called "high."

[0081] Advantageously, the moments of these two minimum compensation forces are approximately equal to zero so that no force is applied to the user when the user's upper limb 202 is in one of the "high" or "low" positions.

[0082] Furthermore, the force moment increases from a first so-called "high" extreme position toward a so-called "working" intermediate position, and decreases from the so-called "working" intermediate position toward a second so-called "resting" extreme position. More specifically, the force moment is monotonic across each of the two ranges, thereby providing a continuously increasing compensation force moment when switching from one of the two extreme positions to the intermediate position.

[0083] 5 shows a graph of the progression of the compensation force F_comp applied by the exoskeleton 100 to the upper limb 202 as a function of the angle of inclination of the arm 110 relative to the horizontal. The force F_comp is an alternative expression of the moment of the compensation force, making it easier to understand the compensation felt by the user.

[0084] 5, in which the compensation force F_comp, expressed in Newtons (N), is shown as a function of the angle formed between the arm 110 and the horizontal axis, expressed in degrees, the maximum compensation force corresponds to approximately 45 N. In other words, in this example, the exoskeleton 100 (when the arm 110 is at 0 degrees relative to the horizontal) can compensate for a load carried by the user having a mass slightly greater than 4.5 kilograms.

[0085] As shown in FIG. 5, the compensation force is zero at the extreme positions corresponding to inclination of the arm 110 of ±90° relative to the horizontal.

[0086] Note that FIG. 5 also shows the force F_arm applied by the compensation member to the arm 110, the maximum of which is slightly shifted towards the so-called "rest" position.

[0087] As mentioned above, the energy source that enables the generation of a moment of force during movement of the upper limb 202 is the elastic element 132 .

[0088] The elastic element 132 is located on the compensation member 130, which according to an advantageous embodiment comprises an upper bar 133 and a lower bar 134, which are parallel. The upper end of the lower bar 134 is fixed to an upper plate 135 and the lower end of the upper bar 133 is fixed to a lower plate 136. The upper bar 133 slides in an opening in the upper plate 135, and the lower bar 134 slides in an opening in the lower plate 136. In other words, the upper bar 133 and the lower bar 134 are slidable so as to be able to assume several positions between a retracted limit state of the compensation member 130, in which they face each other over their entire length, and a deployed limit state of the compensation member 130, in which the two plates are close to or in contact with each other.

[0089] The elastic element 132 extends between and is fixed to the upper plate 135 and the lower plate 136 and preferably corresponds to a tension spring, more preferably to an elastic cable. Thus, switching the compensation member 130 from the retracted state to the deployed state tensions the elastic element 132. In other words, the elastic element 132 tends to drive the compensation member 130 towards the retracted state.

[0090] Alternatively, the compensation member 130 can be made more compact by using a rod that slides inside a tube, with an elastic element fixed to the upper end of the tube and the lower end of the rod. The tension in the elastic element thus induces the rod to retract inside the tube, causing the compensation member to go into compression and return to its retracted state, where the elastic element is in a state of minimum tension. This solution has the advantage of being very compact, with the size being limited to the dimensions of a single tube rather than two tubes.

[0091] It should therefore be understood that to keep the exoskeleton 100 in equilibrium, the elastic elements 132 are primarily under tension, and are continuously under tension during use of the exoskeleton 100. However, other secondary, negligible stresses may occur, and the connections between elements are not mechanically perfect.

[0092] Advantageously, the elastic element 132 is an elastic cable, which comprises an elastic core, preferably made of rubber, and a protective sheath, preferably made of an elastic woven fabric. Such cables are known in the prior art, in particular as "Sandow" cables or belts.

[0093] The load applies a force to the attachment means 120, which in turn applies a moment of force about the arm 110, allowing the arm 110 to rotate.

[0094] A force transmission element 150, which is preferably not elastically deformable, extends between a lower point of the compensation member 130 and the rear end of the arm 110 opposite the front end of the arm 110, in order to act against the force moment applied by the load.

[0095] More specifically, the lower point of the compensation element is in this embodiment a lower fastener 137 fixed to a support bar 138 located between the lower plate 136 and the load-bearing structure 140. The support bar 138 is also provided at its so-called "low" end with the spherical head introduced above.

[0096] The force transmission element 150 is attached to the rear end of the arm 110 using an upper fastener fixed to the arm 110, thereby forming a second pivot 151 about which the arm 110 can pivot. As shown in Figure 4, the upper fastener forms a notch that can fit around the upper bar 133 to increase the range of motion of the arm 110.

[0097] The force transmission elements 150 may be longitudinally rigid parts, such as bars or tubes, but since the force transmission elements 150 are preferably only subjected to tensile stresses, it is advantageous to comprise cables and elements for fastening said cables, which makes the exoskeleton 100 lighter and simpler to design.

[0098] In particular, such cables are cables made of metallic material, advantageously consisting of braided steel wires, known in the prior art, in particular as so-called "Bowden" cables. For the purposes of the present application, such cables can be considered as having a longitudinal dimension which cannot be totally deformed by tension, similar to a rigid element such as a rod or tube, and similar to an elongated element which has substantially no elastic deformation.

[0099] As shown in FIGS. 2-4, the force transmission element 150 advantageously consists of two cables extending parallel and symmetrically on either side of the compensation member 130 .

[0100] It should therefore be understood that to keep the exoskeleton 100 in equilibrium, the force transmission elements 150 are primarily in tension, and are continuously in tension during use of the exoskeleton 100. However, other secondary, negligible stresses may occur, and the connections between elements are not mechanically perfect.

[0101] It is further proposed that the support bar 138 can be generally retracted inside the part 134, which in this case is the lower tube rather than the lower bar. A lower fastening part 137 is fixed to the lower tube 134 and allows adjustment of the relative axial position of the support bar 138 and the lower tube 134. For example, such an adjustable fastening is performed by bolting, the bolts being advantageously provided with knobs for simple setting without tools and directly accessible to the user when the exoskeleton is being worn.

[0102] It is easy to see that, especially in the intermediate position, the force transmission element keeps the arm 110 from tending to rotate about the first pivot 131 by absorbing the moment generated by the load.

[0103] The force generated by the load is then compensated for by the elastic element 132, which generates a compensating force by deformation.

[0104] During the movement of the arm 110, the compensation member 130 is more or less retracted or deployed, depending on the constant length of the force transmission element 150 and the kinematic characteristics of the exoskeleton 100.

[0105] During the movement of the arm 110, the force applied by the elastic element varies and reaches a maximum value when the arm 110 is in a position corresponding to the so-called "low" position. However, the lever arm (perpendicular to the force applied by the elastic element) formed between the first pivot 131 and the rear end of the arm 110 is zero. Conversely, the minimum force applied by the elastic element is reached in the so-called "high" position, where said force approximately corresponds to the weight of the load and the assistance is approximately zero.

[0106] In effect, in this high extreme position, the first and second pivots 131 and 151 and the load application point represented by portion 115 are aligned and the lever arm of the compensation force is zero.

[0107] It will therefore be appreciated that the assistance provided by the exoskeleton will be slightly greater in the range of positions between the "low" and "work" positions due to the stronger force applied by the elastic element 132 over this range.

[0108] As mentioned above, the compensation provided by the exoskeleton depends on the lever arm formed between the first pivot 131 and the rear end of the arm 110, which is perpendicular to the force of the elastic element, i.e. the distance between the first pivot 131 and the rear end of the arm 110.

[0109] The distance between the first pivot 131 and the rear end of the arm 110 is adjustable via a setting mechanism on the arm 110, as the desired compensation depends on the type of activity, the load, and the user's body type.

[0110] Advantageously, the arm 110 is constituted by a rod 111 that can slide into an opening in the first pivot 131 , said opening being located on the part of said first pivot that is fixed to the arm 110 .

[0111] The arm 110 includes at its rear end a setting plate 112 which also includes (or coincides with) the fastening portion of the force transmission element 150 .

[0112] The setting worm screw 113 is mounted so that it can rotate freely within the setting plate 112 without translational movement relative to the setting plate 112 .

[0113] The setting screw 113 cooperates with a threaded opening in a portion of a first pivot 131 fixed to the arm 110 so that the screw 113 extends parallel to the arm 110 .

[0114] Rotation of the screw 113 therefore causes its translational movement relative to the first pivot 131 and therefore translational movement of the arm 110 relative to the first pivot 131 , where the arm 110 is fixed to the screw 113 via the setting plate 112 .

[0115] Such a setting mechanism is particularly easy to use and accessible to the user. Ease of use can be further enhanced by providing a knob on the head of the screw 113, thereby avoiding the need for tools for setting.

[0116] Advantageously, friction reducing elements are incorporated into the setting mechanism to reduce the torque applied by the user to the head of the screw required for setting. More specifically, the screw 113 can be supported by a bearing, plain bearing, or lubricated bushing. In this way, the lever arm can be set while the exoskeleton is in the working position, allowing setting to be performed "in real time" at the time of use, in a particularly intuitive way for the user.

[0117] As mentioned above, the upper limb 202, and more particularly the arm, is secured to the attachment means 120. The attachment means 120 may consist of a single strap secured to the arm 110, but advantageously consists of a double rigid strap.

[0118] For this purpose, a mounting bracket 115 fixed to the front end of the arm 110 cooperates with a mounting clevis 121 of the mounting means 120. The bracket 115 and the clevis 121 are connected, for example, by bolting, leaving a clearance to allow rotation of the mounting means relative to the arm 110. This rotation is limited to a given angular amplitude to allow smooth transitions from the so-called "rest" and "high" extreme positions to intermediate positions. For example, the rotation limitation can be achieved by using a parallel bolt for the mounting bolting of the mounting means 120, so that said bolt abuts against the bracket 115 in a first extreme angular position. The second extreme angular position is defined by a longitudinal cushion abutting the arm 110, which will be introduced below.

[0119] The mounting clevis 121 is fixed to a longitudinal cushion (hard or soft) 122, which advantageously flares out at the end closest to the wearer's elbow in use. Advantageously, the cushion 122 lies along a portion of the wearer's upper arm, towards the wearer's shoulder.

[0120] In this way, the user's arms are supported over most of their length, which increases the comfort and effectiveness of the exoskeleton 100.

[0121] To hold the user's arms on the cushion 122, the cushion 122 comprises at least one, preferably two (or more) straps 124, preferably made of woven fabric, that allow the attachment of the upper limbs 202 to the exoskeleton. Advantageously, such straps have two attachment bands with complementary fastening means designed to cooperate with each other. These fastening means may consist, without distinction, of elements in the form of hooks or elements in the form of buckles, which cooperate with each other and are designed so that the hooks temporarily catch on the buckles. Such fastening means are known to those skilled in the art as "Velcro®" and allow the attachment to be adjusted to suit the user's physique.

[0122] The use of two (or more) straps 124 can limit the degrees of freedom of the arm of the upper limb relative to the attachment means 120. In fact, the use of a single strap made of a flexible material leaves a high degree of rotational freedom of the upper limb relative to the attachment means 120, in other words, a large ball-joint or angular play between the upper limb and the attachment means 120. In this situation, the movements performed by the user, in other words the forces generated, are not all used to pivot the exoskeleton's arms 120, nor does the exoskeleton closely follow the user's natural movements. Therefore, the use of at least two straps 124 spaced a non-zero distance apart can improve the comfort and efficiency of using the exoskeleton.

[0123] Advantageously, as shown in FIG. 6, when the exoskeleton is used in the "intermediate" or "working" position, the mounting bracket 115 is not aligned with the axis of the arm 110, but forms an angle 160 of 0-30° in the so-called "horizontal" plane (parallel to the ground).

[0124] In other words, in the "working" position, the projection of the axis of symmetry of the attachment means 120 through the cushion 122 and the projection of the axis of the arm 110 onto a horizontal plane intersect at an acute angle 160 between 0 and 30°.

[0125] Thus, as shown in FIG. 7, the rear end of the arm 110 is oriented slightly away from the user, thereby avoiding collisions between the arm 110 and the side of the user.

[0126] According to an alternative embodiment, the exoskeleton according to the invention comprises a number of elastic elements, two or more.

[0127] It is not possible to provide an exhaustive list of all possible combinations, as many are possible, but it should be understood that any "self-stressing" type structure following the same design principles is possible.

[0128] For example, a resilient element 132, similar to a tension spring, can be incorporated in series and / or parallel with the compensation member 130. The same output behavior (shown in FIG. 5) can be achieved using a resilient element 132 with a lower elastic constant and smaller dimensions than the preferred embodiment using a single resilient element.

[0129] The advantage this solution offers for comparable performance is greater design freedom in terms of geometry, in this example the compensation member 130 can be curved to conform to the shape of the user's body.

[0130] According to one variant, the elastic constants and lengths of the elastic elements 132 are different in order to obtain an output behavior different from that shown in FIG.

[0131] Thus, a very consistent behavior can be obtained for multiple positions around the working position, i.e., the compensation force felt by the user is approximately constant over an extended angular range, which may be desirable in the context of some activities where the load does not vary with the angle formed by the arm and the horizontal.

Claims

1. 1. An exoskeleton (100) adapted, in use, to assist at least one upper limb (202) of a wearer of said exoskeleton in lifting and carrying a load, said exoskeleton comprising: at least one arm (110) comprising, at one of its ends, called the "front end", at least one means (115) for attaching the upper limbs of said wearer; a load-bearing structure (140) designed to be fixed to said wearer, comprising at least one fulcrum (141); at least one compensation element (130) fixed to said arm by a first pivot (131), extending between said arm and said load-bearing structure to which said compensation element is fixed, and which applies a compensation force moment to said arm by deformation of at least one elastic element (132); a force transmission element (150) extending between the lower point of the compensation member and the end of the arm opposite the front end, called the "rear end"; Features: - the at least one elastic element and the force transmission element are configured to be continuously tensioned during use of the exoskeleton and the moment of tension varies with the tilt of the arms; and the force transmission element is fixed to the arm by a second pivot (151) located at the rear end of the arm, the first pivot being located between the second pivot and the front end of the arm; An exoskeleton (100) comprising:

2. 2. The exoskeleton (100) of claim 1, wherein the arm (110) includes a setting mechanism for setting the distance between the first pivot (131) and the second pivot (151).

3. The setting mechanism: - an opening in said first pivot, in which said arm can slide; a setting plate (112) located at one of the ends of the arm, said setting plate being fixed to a worm screw (113) cooperating with a threaded opening of the first pivot; The exoskeleton (100) of claim 2, comprising:

4. The compensation member (130) comprises: - the state of minimum tension when said upper limb (202) is in a first extreme position, so-called "high"; - maximum tension when the upper limb is in the second extreme position, so-called "rest" The elastic element is provided as follows: The exoskeleton (100) according to any one of claims 1 to 3, wherein the tension in the elastic element causes retraction of the compensation element, the compensation element being in a deployed state and a maximum retracted state in the elevated position and the rest position, respectively.

5. The compensation member (130) comprises: - upper bar (133); and - Lower bar (134) wherein the upper bar and the lower bar are parallel; the upper end of said lower bar is fixed to the upper plate (135); the lower end of said upper bar is fixed to the lower plate (136); 5. The exoskeleton (100) of any one of claims 1 to 4, wherein the upper and lower bars slide within openings in the upper and lower plates, respectively, and the elastic elements (132) extend between the upper and lower plates.

6. The exoskeleton (100) of any one of claims 1 to 5, wherein the at least one elastic element (132) is an elastic cable comprising an elastic core and a protective sheath.

7. An exoskeleton (100) as described in claim 6, wherein the elastic core is made of rubber and the protective sheath is made of elastic woven fabric.

8. The exoskeleton (100) of any one of claims 1 to 7, wherein the force transmission elements (150) comprise elongated elements having substantially no elastic deformability.

9. 9. The exoskeleton (100) of claim 8, wherein the force transmission element (150) comprises two elongated elements on each side of the compensation member extending parallel to each other.

10. The exoskeleton (100) according to claim 8 or 9, wherein the elongated elements are cables.

11. The exoskeleton (100) of any one of claims 1 to 10, wherein the fulcrum (414) is a spherical housing and the compensation member includes a spherical head, thereby forming a ball-joint connection.

12. The exoskeleton (100) of any one of claims 1 to 11, wherein the load-bearing structure (140) is a pelvic belt adapted to grip the hips and / or waist of the wearer.

13. 13. The exoskeleton (100) according to any one of claims 1 to 12, wherein the means (115) for attaching the upper limbs of the wearer comprise longitudinal cushions (122), the projection of the axis of which and the projection of the axis of the arms onto a so-called "horizontal" plane intersect at an angle (160) between 0 and 30 degrees when the exoskeleton is in a so-called "working" position.

Images