FR3018680A1 - EXOSQUELETTE COMPRISING A SUBSTITUTE WITH AN ANKLE - Google Patents

Abstract

In an exoskeleton, a leg structure (302) is arranged to mingle with a leg of a person carrying the exoskeleton having a foot and ankle to that leg. A foot structure (308) comprising a support plane (310) on which the foot can bear when the foot is flat. This support plane has a median longitudinal axis. An ankle pivot connection (318) connects the foot structure to the leg structure. The ankle pivot connection has a pivot axis (1201) having: - an angle (β) in a range of 0 ° to 30 ° with respect to the support plane (310) of the foot structure, and - an angle ( α) in a range of 0 ° to 45 ° with respect to a plane (1202) perpendicular to the median longitudinal axis of the support plane.

Description

EXOSQUELETTE COMPRISING A SUBSTITUTE WITH AN ANKLE. TECHNICAL FIELD [0002] One aspect of the invention relates to an exoskeleton comprising a substitute for an ankle. [0003] STATE OF THE PRIOR ART [0004] The patent publication WO 2011/002306 describes a control system for controlling an exoskeleton worn by a user and comprising one or more actuators associated with the various members of the exoskeleton, each corresponding to a part of the user's body. The exoskeleton comprises two actuators at an ankle: a main foot actuator and a secondary foot actuator. The main foot actuator is configured to actuate a rotation of a foot member relative to a lower leg structural member. This rotation is effected by means of a ball joint about an axis substantially parallel to an axis of rotation of a knee connection. The secondary foot actuator is configured to actuate a rotation of the foot member in a substantially median / lateral plane around the aforementioned pivot link. The secondary foot actuator is also configured to actuate a rotation of an upper leg structural member associated therewith in a median / lateral plane of about six degrees on either side of a vertical. SUMMARY OF THE INVENTION [0007] There is a need for a solution for making exoskeletons of simplified structure, lighter, less bulky, and less energy consuming. POMO According to one aspect of the invention, an exoskeleton comprises: - a leg structure arranged to rub a leg of a person carrying the exoskeleton having a foot and ankle to that leg, a foot structure comprising a support plane on which the foot can abut when the foot is flat, the support plane having a median longitudinal axis, - an ankle pivot connection connecting the foot structure to the leg structure, the ankle pivot connection having a pivot axis having: - an angle in a range of 0 ° to 30 ° with respect to the support plane of the foot structure, and - an angle in a range of 0 ° to 45 ° with respect to a plane perpendicular to the median longitudinal axis of the support plane. In such an exoskeleton, the pivot axis of the ankle pivot connection has a particular orientation: the pivot axis is contained in no reference plane: frontal, sagittal or horizontal. This particular pivotal axis, which is oblique, allows the exoskeleton to produce movements at an ankle that are close to natural movements, especially those that are most frequent and important at this level. A single pivot connection and a single actuator are therefore sufficient at the ankle. In contrast, the exoskeleton disclosed in the aforementioned patent publication comprises two pivot links and two actuators for producing movements at an ankle. The exoskeleton according to the invention can therefore be of simpler structure, lighter, less bulky, and less energy consuming. [cm o] An embodiment of the invention may include one or more of the following additional features as defined in the following paragraphs. The exoskeleton may comprise an actuating device disposed between the leg structure and the foot structure to cause pivoting of the foot structure relative to the leg structure according to the pivot axis of the pivot connection. ankle. The actuating device may comprise a universal joint, a ball joint, and an actuator disposed between the universal joint and the ball joint. These elements allow a kinematic loop that can perform movements in three dimensions. During these movements the actuator remains along a lower segment of the leg structure. This allows a small footprint of this set and avoids interference between the actuator and the leg of the person wearing the exoskeleton. The support plane of the foot structure may comprise a front platform and a rear platform, the rear platform being connected to the ankle pivot connection, and a foot pivot connection which connects the platform. forward to the aft deck. The foot pivot connection constitutes a break in the support plane allowing a smoother, less jerky, more natural and faster running movement with respect to a single-piece support plane without breakage. The foot pivot connection may comprise an elastically deformable member arranged to store energy when the front platform is folded relative to the rear platform. The elastically deformable member makes it possible to recover a portion of the potential energy that is released during a phase in a walking process that is characterized by a controlled fall towards the front. The elastically deformable member stores this energy to restore it to another phase, for example, when the foot structure takes off from the ground at the end of the step. The foot pivot connection is located in a quadrant delimited by a median sagittal section of the person carrying the exoskeleton and a frontal section passing through the leg, the foot pivot connection having a pivot axis defining a right triangle in this same quadrant and having an angle in a range of 45 ° to 90 ° with respect to the median sagittal section. The rear platform may be closer to the median sagittal section than the front platform, so that the median longitudinal axis of the support plane has an angle between 0 ° and 45 ° relative to the median sagittal section when the exoskeleton is in the resting position. This outward orientation makes it possible to better reproduce a human step since the human feet are also oriented in this way. In addition, during a step, during a push phase, this orientation makes it possible to better direct the thrust. The thrust thus includes a latero-medial component, in order to propel the body of the person carrying the exoskeleton of a carrier foot to a receiving foot. The leg structure may comprise an upper leg segment disposed to co-operate with an upper portion of the leg above a knee of the person carrying the exoskeleton, a lower leg segment disposed to meet a portion of the leg. lower leg below the knee, and a pivot knee link connecting the lower leg segment to the upper leg segment. [0018] The upper leg segment may have an inclination in a range of 0 ° to 300 relative to the lower leg segment when the exoskeleton is in the rest position, so that an upper end of the upper leg segment more distant from a median sagittal section of the person carrying the exoskeleton than a low extremity. This inclination allows the exoskeleton to perform weight transfer to a foot faster and more energy-efficient, compared to a structure without such inclination. The inclination reduces a displacement of the center of gravity that is necessary for it to be above a supporting foot. The exoskeleton may comprise a pelvic structure arranged to be attached to the pelvis of the person carrying the exoskeleton, a pivot connection leg orientation disposed between the pelvic structure and the leg structure, the pivot connection orientation leg having a vertical pivot axis when the exoskeleton is in the rest position. This allows one leg to perform vertical rotations, which may be involved in a stabilization process and in a walking process. These vertical rotations contribute to these processes being effective and perceived as being natural by the person wearing the exoskeleton. The exoskeleton may comprise a control device adapted to control at least one actuator included in the exoskeleton. The control device may comprise a detector adapted to detect at least one dynamic parameter of at least a portion of the bust of the person carrying the exoskeleton, and a processor capable of applying a control signal to an actuator based on of the detected parameter. This allows an intuitive control of the exoskeleton: the command is forgotten, the exoskeleton is allowed to use naturally. It should be noted that this aspect does not depend on the aspects described in the foregoing. For example, the appearance of the control can be implemented without the exoskeleton comprising an ankle pivot connection as defined in the foregoing, characterized by an oblique pivot axis. The detector may comprise at least one inertial sensor. The processor may be able to perform several control modes, including: a stabilization control mode in which the processor controls at least one actuator to maintain the person carrying the exoskeleton in a rest position, and a mode of a walk control in which the processor controls at least one actuator to assist the person wearing the exoskeleton to walk. The processor may be able to determine a position of a center of gravity of at least a part of the body of the person carrying the exoskeleton and to apply a control mode depending on the position of the center of gravity . The processor can be adapted to associate different control modes respectively to different areas in a plane on which the center of gravity is projected, the processor can thus apply a control mode associated with an area in which is the center of gravity. By way of illustration, a detailed description of some embodiments of the invention is presented in the following with reference to attached drawings. SUMMARY DESCRIPTION OF THE DRAWINGS - Figure 1 is a schematic front view of a person who can wear an exoskeleton. - Figure 2 is a schematic side view of the person. Figure 3 is a perspective view of a portion of an exoskeleton comprising lower limbs. - Figure 4 is a back view of a pelvis structure of the exoskeleton. FIG. 5 is a schematic diagram of the exoskeleton in a state of rest. - Figure 6 is a schematic diagram of the exoskeleton in a state operated at the basin structure. - Figure 7 is a schematic diagram of the exoskeleton in another actuated at the basin structure. - Figure 8 is a simplified schematic diagram of the exoskeleton in the state of rest. - Figure 9 is a top view of two foot structures of the exoskeleton. - Figure 10 is a bottom view of a support plane of a left foot structure of the exoskeleton. - Figure 11 is a simplified schematic diagram of the left foot structure. - Figure 12 is a perspective view of a lower left portion of the exoskeleton comprising a pivot pin connection. - Figure 13 is a schematic diagram showing a pivot axis of the ankle pivot connection. FIG. 14 is a schematic diagram showing a projection plane for a control mode selection. DETAILED DESCRIPTION [0028] Figures 1 and 2 illustrate a person who can wear an exoskeleton 300. Figure 1 provides a schematic front view of the person. Figure 2 provides a schematic side view of the person. The person has two legs, a left leg 101 and a right leg 102, respectively with a left knee 103 and a right knee 104. The person has two ankles, a left ankle 105 and a right ankle 106, and two feet, one foot 107 and a right foot 108. The person also has a bust 109, a pelvis 110, hips 111, 112 and kidneys, the latter organs are not shown in Figures 1 and 2 for reasons of simplicity and convenience . Figures 1 and 2 also illustrate a medial sagittal section 113 of the person. This section comprises an axis 114 corresponding to a direction in which the person could typically perform a walk. This axis will be called "direction of the walk" in what follows. Figures 1 and 2 further illustrate a frontal sectional view 115 passing through both legs 101, 102. Figure 1 illustrates two orientations: medial 116 (113) and lateral 117 (opposite 115). Figure 2 illustrates two other orientations: anterior 118 (or before) and later 119 (or rear). Figure 3 illustrates an exoskeleton 300 that the person illustrated in Figures 1 and 2 can wear. Figure 3 provides a perspective view of the exoskeleton 300. The exoskeleton 300 includes a pelvic structure 301 which lies behind the kidneys of the person when wearing the exoskeleton 300. The pelvic structure 301 may be attached. to pelvis 110 shown in Figure 1. This attachment can be flexible by means of, for example, a harness or one or more straps, or a combination of such elements. These elements are not shown in Figure 3 for reasons of simplicity and convenience. The exoskeleton 300 further comprises two leg structures: a left leg structure 302 and a right leg structure 303. The left leg structure 302 is arranged to mate with the left leg 101 of the person shown in Figs. and 2. The right leg structure 303 is arranged to mate with the right leg 102 of that person. [0033] In more detail, the left leg structure 302 includes an upper leg segment 304 and a lower leg segment 305. The upper leg segment 304 is disposed to mate with an upper portion of the left leg 101 lying on top of the left leg. above the left knee 103 of the person shown in Figures 1 and 2. The lower leg segment 305 is arranged to co-operate with a lower portion of the left leg 101 lying below the left knee 103. Similarly, the right leg structure 303 also includes an upper leg segment 306 and a lower leg segment 307 shown in FIG. 3. The exoskeleton 300 comprises two foot structures: a left foot structure 308 and a right foot structure 309. The left foot structure 308 comprises a support plane 310 on which the left foot 107 of the person illustrated in Figures 1 and 2 can bear when the left foot 107 is flat. Similarly, the right foot structure 309 comprises a support plane 311 on which the right foot 108 can bear when the right foot 108 is flat. The exoskeleton 300 comprises two hip structures: a left hip structure 314 arranged to meet a left hip 111 of the person and a right hip structure 315 disposed to meet a right hip 112 of the person illustrated in FIGS. and 2. The exoskeleton 300 includes a plurality of pivot links: a pair at the hips, a pair at the knees, and a pair at the ankles. [0037] In more detail, the pair of pivot connections at the hips comprises a left hip pivot link 312 and a right hip pivot link 313. The left hip pivot link 312 connects the left leg structure 302 rotatably to the structure Likewise, the right hip pivot link 313 connects the right leg structure 303 to the right hip structure 315. [0038] The knee pivot link pair includes a left knee pivot link 316 and a right knee pivot connection 317. The left knee pivot connection 316 connects the lower leg segment 305 of the left leg structure 302 to the upper leg segment 304 of this structure. Similarly, the right knee pivot connection 317 connects the lower leg segment 307 of the right leg structure 303 to the upper leg segment 306 of this structure. The pair of ankle pivot links comprises a left ankle pivot connection 318 and a right ankle pivot connection 319. The left ankle pivot connection 318 connects the left foot structure 308 to the left leg structure 302. Similarly, pivot connection Right ankle 319 connects the right foot structure 309 to the right leg structure 303. The exoskeleton 300 further comprises other pivot links. These other pivotal links will be presented and described in the following. The exoskeleton 300 comprises several actuating devices 320-325. An actuating device is associated with a pivot connection mentioned in the foregoing. The actuating device allows the elements connected by the pivot connection in question to rotate with respect to one another. Thus, the exoskeleton 300 includes a left knee actuator 320, a right knee actuator 321, a left hip actuator 322, a right hip actuator 323, a left ankle actuator 324, and a right ankle actuator 325. [0042] The left knee actuator 320, which is associated with the left knee pivot link 316, is described in more detail by way of example. The left knee actuator 320 includes an actuator 326 and two rotatable connecting members 327, 328. A rotatable connecting member 327 connects an end of the actuator 326 to the upper leg segment 304 at a connection point relatively remote from the the left knee pivot connection 316. The other rotary connection member 328 connects another end of the actuator 326 to the lower leg segment 305 at a connection point relatively close to the left knee pivot connection 316, just below that -this. The actuator 326 is able to perform a linear movement between its ends. This linear movement is transformed into a rotational movement of the lower leg segment 305 relative to the upper leg segment 304.

Rotating connecting member 327 may comprise a cardan joint. The other rotary connection member 328 may comprise a ball joint. Figure 3 illustrates this arrangement, which can also be reversed. Such an arrangement allows left knee actuator 320, as well as leg segments, upper 304 and lower 305, to perform useful three-dimensional movements. The connection points, mentioned in the above, remain fixed respectively with respect to the upper leg segment 304 and with respect to the lower leg segment 305. The actuating device 320 associated with the left knee pivot connection 316 constitutes indeed a quadrilateral having a segment of variable length. This segment is the actuator 326 which can be in the form of a jack. This jack can be, for example, an electric cylinder, hydraulic, pneumatic or any other type of linear actuator. The cylinder has an adjustable length by means of a control signal applied to the cylinder. The actuator 326 associated with the left knee pivot connection 316 will be designated "left knee actuator 326" in the following for reasons of clarity and convenience. The other actuating devices 321-325 mentioned in the foregoing have a similar structure and therefore operate in a similar manner. These actuators also comprise actuators 329-333 shown in FIG. 3. These actuators will respectively be designated by "right knee actuator 329", "left hip actuator 330", "right hip actuator 331", "left ankle actuator 332 ", And" right ankle actuator 333 "in the following for reasons of clarity and convenience. The adjective of such a designation indicates the pivot link to which the actuator is associated. Figure 4 illustrates the basin structure 301 of the exoskeleton 300 in more detail. This figure provides a back view of the pond structure 301. The pond structure 301 comprises a central pond segment 401 disposed to be attached to the tank 110 of the person illustrated in FIGS. 1 and 2. The central pond segment 401 can therefore include one or more fasteners, such as a harness or one or more straps, as mentioned above. The basin structure 301 comprises a pair of peripheral pelvic segments: a left peripheral pelvic segment 402, and a right peripheral pelvic segment 403. The pelvic structure 301 comprises a pair of pivot links: a left basin pivot connection 404 and right basin pivot connection 405. The left basin pivot connection 404 connects the left peripheral basin segment 402 to the central basin segment 401. The right basin pivot connection 405 connects the right peripheral basin segment 403 to the segment 401. These basin pivot connections, left 404 and right 405, each have a horizontal pivot axis when the exoskeleton 300 is in the rest position. The pelvic structure 301 further comprises a pair of leg orientation pivot connections: a left leg orientation pivot connection 410 and a right leg orientation pivot connection 411. The left leg orientation pivot connection 410 connects the left peripheral pelvic segment 402 to the left hip structure 314. The right leg pivot connection 411 connects the right peripheral pelvic segment 403 to the right hip structure 315. The leg pivot connections, left 410 and right 411, have a vertical pivot axis when the exoskeleton 300 is in the rest position. An actuating device 406 is associated with the pair of pivot pivot connections 404, 405. This device comprises an actuator 407 and two joints. A left articulation connects a left end of the actuator 407 to a connecting rod of the left peripheral pelvic segment 402. A right articulation connects a right end of the actuator 407 to a connecting rod of the right peripheral pelvic segment 403. The actuator 407 can be in the form of a jack. This jack can be, for example, an electric cylinder, hydraulic, pneumatic or any other type of linear actuator. The actuator will be designated by "basin actuator 407" in the following for reasons of clarity and convenience. The basin actuator 407 has an adjustable length by means of a control signal applied to the basin actuator 407. [0051] A left blocking device 408 is associated with the left basin pivot connection 404. The left blocking device 408 is switchable between an unlocked state and a locked state. In the unlocked state, the left blocking device 408 allows pivoting of the left peripheral pelvic segment 402 with respect to the central pelvic segment 401. This pivoting is possible thanks to the left pelvis pivot connection 404. On the other hand, in the locked state, the left blocking device 408 prevents such pivoting. In this state, the left peripheral basin segment 402 is rigidly connected to the central pond segment 401. [0052] Similarly, a right blocking device 409 is associated with the right basin pivot connection 405. The right blocking device 409 is also switchable between an unlocked state and a latched state to, respectively, allow and prevent pivoting of the right peripheral pelvic segment 403 relative to the central pelvic segment 401. [0053] This arrangement of the pelvic structure 301 allows lateral rotational movements at the basin 110. Such rotational movement occurs either on the left side of the basin structure 301 or the right side, at a given time. This in function of a blocking respectively of the right pelvis pivot connection 405 or the left pelvis pivot connection 404. These lateral rotational movements can intervene in a stabilization process of the person carrying the exoskeleton when the person is standing and at the same time. 'stop. This process will be described in more detail in the following. The lateral rotational movements can also advantageously intervene in a walking process: the person wearing the exoskeleton walks in a straight line. These movements are then alternating on the left and right side in a way that can be regular. They provide left-right pulses at pelvis 110 during the walking process. These movements thus contribute to a dynamic balance of a forward movement. In fact, a walking process is generally characterized by an asymmetry of the ground supports: left foot 107 then right foot 108. The lateral rotation movements, and alternating left-right, contribute to compensate dynamically this asymmetry. The left pelvis pivot connection 404 may comprise an elastically deformable member. The right pelvis pivot connection 405 may also comprise an elastically deformable member. These elastically deformable members may comprise, for example, one or more torsion springs. They will be designated respectively by "left basin spring" and "right basin spring" in the following for reasons of convenience. The left pelvic spring can store kinetic energy when the left peripheral pelvic segment 402 pivots relative to the central pelvic segment 401 from a home position. This energy can be reinjected when the left peripheral pelvic segment 402 reverses. This reduces power consumed by the actuator basin 407; the left basin spring can assist the basin actuator 407 to perform reverse pivoting. The same remarks apply to the right pelvic spring, which can store kinetic energy when the right peripheral pelvic segment 403 is pivoted. The basin structure 301 shown in Figure 4 and described above is particularly suitable for artificial reproduction of a human step. A process of subsidence of the pelvis 110 intervenes in human walking, on the side of an oscillating leg taking a step forward. During a forward tilting and propulsion phase, the foot of the other leg, which serves as a support, bends and the ankle passes into plantar flexion. Without collapse of the basin 110, the center of gravity of the human body would then tend to rise mechanically, which consumes energy as much as superfluous. The basin structure 301 is adapted to collapse laterally on the side of the oscillating leg. This slump can be effected by using masses present on this side. This results in a local fall by gravity, which is controlled by the basin structure 301, in particular by the basin actuator 407. This has the effect of reducing an overall elevation of the center of gravity that would occur without subsidence of the basin 110. Moreover, the gravity-induced local fall releases energy, a portion of which is stored in the basin spring in the pivot connection left free. Then, when the oscillating leg comes into contact with the ground at the end of the step, the side of the basin structure 301 which had sagged is raised. The energy stored in the spring can then be used. The actuators of the exoskeleton 300 associated with the oscillating leg which has just come into contact with the ground, also help raise the pelvis 110. The actuator basin 407, which also comes into play, is therefore not not only to act. It is sufficient for the basin actuator 407 to supply only a part of the energy necessary to raise the basin structure 301. The basin actuator 407 can thus be a relatively low-power device and, as a result, relatively weak. dimensions. This allows compact embodiments of the basin structure 301. [0060] The pivot links leg orientation 410, 411 are actuated. An actuator 412 is associated with the left-leg pivot connection 410. Similarly, an actuator 413 is associated with the right-leg pivot connection 411. These actuators 412, 413 may each be in the form of an electric geared motor comprising an electric motor. and one or more reduction stages. These reduction stages couple the electric motor to the leg pivot connection concerned. The reduction stages may comprise, for example, one or more gears, one or more worm and worm gear units, one or more epicyclic reduction gears and any other type of mechanical gear unit. The actuators 412, 413 will be designated respectively "left leg orientation actuator 412" and "right leg orientation actuator 413" in the following for reasons of clarity and convenience. The left leg pivot connection 410 thus allows a motorized vertical rotation of the left leg structure 302 relative to the central pelvic segment 401. Similarly, the right leg pivot connection 411 allows a motorized vertical rotation of the structure 303 right leg compared to the central pelvic segment 401. These vertical rotations can intervene in a process of stabilization and in a walking process.

Vertical rotations contribute to these processes being effective and perceived as natural by the person wearing the exoskeleton. For example, a vertical rotation of the left leg structure 302 allows to properly orient the left foot structure 308 to make a left turn. Likewise, a vertical rotation of the right leg structure 303 may contribute to a right-hand cornering. In other cases, the leg pivot pivot connections 410, 411 enable the pelvic structure 301 to be pivoted with respect to a leg. This allows weight transfer to the left or right. This weight transfer can advantageously intervene to initiate a step movement; the weight is transferred to a supporting leg. Standing balancing also typically involves weight transfer in which leg pivot pivot links 410, 411 may play a role. The pivot links orientation leg 410, 411 can also be involved in a walking process. Vertical rotation of the pelvic structure 301 relative to a supporting leg allows to lengthen a step and, consequently, to make the walking process more efficient. FIG. 5 illustrates the exoskeleton 300 in a state of rest. The exoskeleton 300 is represented by a schematic diagram. Elements identical or similar to those presented in the foregoing are marked with identical reference signs. The exoskeleton 300 comprises a control device 501 adapted to control various actuators: the actuator basin 407, the actuator orientation left leg 412, the right leg orientation actuator 413 'the left knee actuator 326, the right knee actuator 329, left hip actuator 330, right hip actuator 331, left ankle actuator 332, and right ankle actuator 333. The control device 501 can also control the left lock device 408 and the right blocking device 409, illustrated in FIG. 4, associated respectively with the left basin pivot connection 404 and with the right basin pivot connection 405. The control device 501 can control any of the aforementioned elements by means of a control signal transmitted to the element concerned. This transmission can be wired or wireless. The control device 501 comprises a detector 510 capable of detecting a dynamic parameter of a body part of the person carrying the exoskeleton. This part of the body is preferably free of the exoskeleton 300, that is to say not connected to it. This body part may be, for example, the bust 109 of the person carrying the exoskeleton illustrated in FIG. 1. In this case, the dynamic parameter may comprise a position of the bust 109, a movement speed of the bust 109, or an acceleration of the bust 109. The detector 510 may comprise a set of inertial sensors 511, 512, 513. For example, two inertial sensors 511, 512 may be located on the chest of the person carrying the exoskeleton. Another inertial sensor 513 may be located at the level of the navel. This place corresponds to a natural center of gravity for a human person. The set of inertial sensors 511, 512, 513 defines, indeed, a triangle. This arrangement makes it possible to detect numerous positions, or numerous movements, of the bust 109 with respect to the legs 101, 102, and therefore with respect to the exoskeleton 300. For example, the set of inertial sensors 511, 512, 513 can detect the following positions of the bust 109: leaning forward, leaning back, leaning on the right side, leaning on the left side. The set of inertial sensors 511, 512, 513 can also detect a state of rocking of the basin 110 during a walking process, or a rotation of the bust 109. The control device 501 comprises a processor 514 which receives one or more detection signals from the detector 510. These detection signals indicate a position or movement of the bust 109. The processor 514 can thus apply a control signal to one or more of the actuators 407, 412, 413, 326, 329 -333 mentioned in the above depending on the position, or movement, of the bust 109 of the person carrying the exoskeleton. Moreover, the processor 514 can also receive signals from the actuators, giving information on them. The processor 514 can take these signals into account to establish control signals. In doing so, the processor 514 may implement a servo loop for an actuator. The processor 514 can determine a set value for this servo loop, and therefore the actuator in question, from the detection signals coming from the detector 510. More specifically, the processor 514 can add a mode of Specific operation of the exoskeleton 300 at a position or movement of the bust 109. The processor 514 may then generate one or more control signals appropriate for one or more actuators. For example, the processor 514 can interpret the position "leaned forward" in a will to advance. In this case, the processor 514 controls the actuators of the exoskeleton 300 so that forward movement is performed. This may correspond to a "forward operating" mode of operation. The processor 514 may also employ the detection signals to sway the pond structure 301 during this walk. The processor 514 can thus stabilize the person carrying the exoskeleton in its forward march and act on the exoskeleton 300 if corrections are necessary. In another example, the processor 514 may interpret a relatively abrupt motion detection as a need to rebalance the exoskeleton 300. Such a controller 501 has several advantages. The person can control the exoskeleton 300 intuitively. This command is forgotten; the exoskeleton 300 can be used naturally.

The exoskeleton 300 and its control reproduce a mechanism of "fall catch" characteristic of a human march. This also provides an energetic advantage: the exoskeleton 300 can usefully utilize energy produced by a fall forward in a walking process. This reduces a demand for electrical power to implement this process. FIG. 6 illustrates the exoskeleton 300 in a state actuated at the basin structure 301. The exoskeleton 300 is represented by a schematic diagram similar to that of FIG. 5. In the actuated state illustrated in FIG. Figure 6, the right leg structure 303 tilts slightly laterally. To do this, the right basin pivot connection 405 is in the unlocked state, while the left basin pivot connection 404 is in the locked state. The basin actuator 407 expands in length under control of the processor 514. Both ends of the basin actuator 407 move away causing the right peripheral basin segment 403 to pivot relative to the central pond segment 401. [0072 Fig. 7 illustrates the exoskeleton 300 in another state actuated at the pelvic structure 301. The exoskeleton 300 is represented by a schematic diagram similar to those of Figs. 5 and 6. In the actuated state illustrated in FIG. Figure 7, which can be considered the opposite of that shown in Figure 6, is the left leg structure 302 which tilts slightly laterally. To do this, the left basin pivot connection 404 is in the unlocked state, while the right basin pivot connection 405 is in the locked state. Here again, the basin actuator 407 widens in length under the control of the processor 514. The two ends of the basin actuator 407 move away causing in this case a pivoting of the left peripheral basin segment 402 relative to the central basin segment 401 The actuated states illustrated in FIGS. 6 and 7 can be used, for example, during a stabilization process, the person carrying the exoskeleton being standing, static, or during a walking process. These processes can include a multitude of movements. A movement at the ankles, especially lateral, directs the upper body. This movement is typically combined with movements at the pelvic structure 301, which is not necessarily limited to those illustrated in FIGS. 6 and 7. [0074] A stabilization process, or a walking process, typically involves a transfer. the weight of the body of the person wearing the exoskeleton. For example, a transfer of body weight to the left or, where appropriate, to the right is important to start the walking process. The left leg pivot connection 410 or, where appropriate, the right leg pivot connection 411 is involved in this transfer of weight. These leg-orientation pivot connections 410, 411 enable the pond structure 301 to rotate with respect to a supporting leg, resulting in the transfer of weight. By transferring the weight of the body to one foot, the other foot is released and can leave the ground. Weight transfer can also be involved in the stabilization process, in response to external disturbances, for rebalancing in the upright position. During a weight transfer, the exoskeleton 300 may be required to perform several types of rotation at the pelvis 110 of the person carrying the exoskeleton. There are three rotations in relation to each leg. Rotations along a vertical axis can be effected by means of the left leg pivot connection 410 and the right leg pivot connection 411. Rotations along a horizontal axis, perpendicular to the front section 115 illustrated in FIGS. 1 and 2, can be effected by means of the left basin pivot connection 404 and the right basin pivot connection 405. Rotations along a horizontal axis, perpendicular to the median sagittal section 113 illustrated in FIGS. 1 and 2, can be effected by means of the left hip pivot link 312 and the right hip pivot link 313. [0076] Fig. 8 further illustrates the exoskeleton 300 in the idle state. Figure 8 is a schematic diagram simplified with respect to Figure 5. Figure 8 illustrates that the upper leg segment 304 of the left leg structure 302 has an inclination 801 with respect to the lower leg segment 305 when the exoskeleton 300 is in the state of rest. This inclination 801 is such that an upper end 802 of the left upper leg segment 304 is further away from the medial sagittal section 113 of the person carrying the exoskeleton than a lower end 803. The inclination 801 can be included in a range of 0 ° to 30 °. The same remarks apply to the upper leg segment 306 of the right leg structure 303, which has an inclination 804 with respect to the lower leg segment 307. The tilt 801, 804 of the upper leg segments, left 304 and right 306, reproduces a natural inclination. The femurs of a human are typically inclined to the vertical when the human is in the normal position, standing. By reproducing this inclination, the exoskeleton 300 is able to perform a weight transfer to a foot more quickly and more energy-saving, compared to a structure without such inclinations. The inclination reduces a displacement of the center of gravity that is necessary for it to be above a support foot. FIG. 9 illustrates in greater detail the two foot structures 308, 309 of the exoskeleton 300. FIG. 9 provides a view from above of these two foot structures: the left foot structure 308 and the foot structure 309. The support plane 310 of the left foot structure 308 has a median longitudinal axis 901 shown in Figure 9. Similarly, the support plane 311 of the right foot structure 309 has a median longitudinal axis 902 also indicated to this figure. The support plane 310 of the left foot structure 308 comprises a front platform 903 and a rear platform 904. A foot pivot connection 905 connects the front platform 903 to the rear platform 904. The rear platform 904 is connected to the left ankle pivot connection 318. The foot pivot connection 905 comprises an elastically deformable member 906, which may be in the form of a torsion spring. This elastically deformable member will be referred to as "torsion spring 906" in the following for reasons of convenience. The torsion spring 906 is capable of storing energy in potential form when the front platform 903 is folded with respect to the rear platform 904. The support plane 311 of the right foot structure 309 has a similar structure, comprising comprises a front platform 907, a rear platform 908, and a foot pivot connection 909. posol The foot pivot connection 905 constitutes a break of the support plane 310 allowing a more smooth, jerky running movement , more natural and faster compared to a support plane in one part, without breakage. During a walking process, a support plane in one part, without breakage, should leave the ground, either parallel to this ground, or ending with a point or linear support very difficult to control. Foot pivot connection 905 thus contributes to reproducing more faithfully a walking function that the person carrying the exoskeleton has lost. This also contributed to an easier acceptance of the exoskeleton 300 by the wearer, as well as easier and faster accommodation. Another advantage of the foot pivot connection 905 consists of a forward propulsion effect when the rear platform 904 off the ground, while the platform before 903 continues to rest on the ground. The break, formed by the foot pivot connection 905, constitutes an axis of rotation for a controlled fall movement. This axis of rotation makes it possible to add a forward translation component to the controlled fall movement. This forward propulsion effect is important in a dynamic walk of a human being. The effect makes it possible to lengthen a step in an energy efficient manner. The torsion spring 906 makes it possible to recover a portion of the potential energy that is released during the fall forward. Indeed, the torsion spring 906 has a stiffness which is countered by the fall forward. The torsion spring 906 stores this energy to restore it when the left foot structure 308 lifts off the ground at the end of the step. The description of the left foot structure 308 in the foregoing applies mutatis mutandis to the right foot structure 309. [0083] Figure 10 illustrates other aspects of the left foot structure 308 that apply. also to the right foot structure 309. Figure 10 provides a bottom and perspective view of the support plane 310 of this foot structure. The support plane 310 comprises a flexible sole 1001 able to come into contact with the ground. This flexible sole 1001 is located below a rigid frame, which can be in the form of two metal plates 1002, 1003 connected to one another by the foot pivot connection 905. [0084] The flexible sole 1001 presents a surface capable of coming into contact with the ground. This surface is delimited by rounded edges 1004 clearly shown in Figure 10. These rounded 1004 of the flexible sole 1001 are located in particular at the ends of the foot and on the sides. The roundings 1004 allow to further fluidize a forward movement. The flats 1004 of the sole on its sides allow the feet to roll slightly on these sides, especially when the pelvic structure 301 produces side pulses to balance a parasitic side movement, standing upright when stopped. FIG. 11 further illustrates the left foot structure 308. FIG. 11 is a simplified schematic diagram with respect to FIG. 9. FIG. 11 illustrates that the foot pivot connection 905 lies in a quadrant delimited by the sagittal section. median 113 of the person carrying the exoskeleton and the frontal cut 115 passing through the leg. Foot pivot connection 905 has a pivot axis 1101 defining a right triangle in the same quadrant. The pivot axis 1101 has an angle 1102 in a range of 45 ° to 90 ° relative to the middle sagittal cut 113. [0086] Fig. 11 further illustrates that the rear platform 904 is closer to the The median longitudinal axis 901 of the support plane 310 then has an angle 1103 between 00 and 45 ° relative to the medial sagittal section 113 when the exoskeleton 300 is in position. rest. This range of angles may also have a lower lower limit, for example, one or a few degrees. The left foot structure 308 of the exoskeleton 300 is therefore oriented outwards by an angle, which may be 15 °, with respect to a sagittal direction rather than being oriented straight in the direction sagittal. This outward orientation makes it possible to better reproduce a human step since the human feet are also oriented in this way. In addition, during a step, during a push phase, this orientation of the foot makes it possible to better direct the thrust. The thrust thus comprises a lateromedial component, in order to propel the body of the person carrying the exoskeleton of a carrier foot to a receiving foot. FIG. 11 illustrates that the foot pivot connection 905, which forms the breakage of the left foot structure 308, is oriented so as to be almost perpendicular to the sagittal section, that is to say almost perpendicular to the axis of the walk. In this example, the foot pivot connection 905 is not perpendicular to the median longitudinal axis 901 of the support plane 310 of the left foot structure 308. This orientation of the foot pivot connection 905 allows a tilting of the exoskeleton 300, as well as the person who carries it, forward in the direction of the march. The left ankle pivot connection 318 also plays a role in this tilt having an anteromedial orientation, which will be described in the following. FIG. 12 illustrates a lower left portion of the exoskeleton 300 comprising the left ankle pivot connection 318. FIG. 12 provides a perspective view of the lower left portion of the exoskeleton 300. FIG. 12 illustrates that the link left ankle pivot 318 has a pivot axis 1201 having a particular orientation. The pivot axis 1201 can be qualified as oblique because it is not contained in any reference plane: frontal, sagittal or horizontal. In contrast, the pivot axis 1201 is oriented in the following manner: latero-medial, postero-anterior, dorso-plantar. The pivot axis 1201, however, comprises a principal component perpendicular to the median longitudinal axis 901 of the support plane 310 of the left foot structure 308, illustrated in FIG. 9. [0090] FIG. 12 also illustrates in greater detail the left ankle actuator 324 associated with the left ankle pivot connection 318. The left ankle actuator 332 of this device is disposed between the left leg structure 302, of which FIG. 12 illustrates the lower leg segment 305, and the structure The left ankle actuator 324 may pivot the left foot structure 308 relative to the left leg structure 302 along the pivot axis 1201 of the left ankle pivot link 318. [0091 The left ankle actuator 324 includes a cardan joint 1202 and a ball joint 1203 in addition to the left ankle actuator 332. The cardan joint 1202 connects one end. from the left ankle actuator 332 to the left foot structure 308, specifically to the rear platform 904 thereof. The ball joint 1203 connects another end of the left ankle actuator 332 to the lower leg segment 305 at a connection point remote from the left foot structure 308. The left ankle actuator 332 may be in the form of a jack , as it has been mentioned in the foregoing. The left ankle actuator 332 is located posteriorly to the lower leg segment 305 and is in a way similar to a soleus muscle. The left ankle actuator 324, the left ankle pivot connection 318, the lower leg segment 305, and the left foot structure 308 form a kinematic loop. This kinematic loop can perform three-dimensional movements, which therefore do not remain in a reference plane. During these movements the left ankle actuator 332 remains along the lower leg segment 305 of the exoskeleton 300. This allows a small footprint of this assembly and avoids interference between the left ankle actuator 332 and the left leg 101 of the person carrying the exoskeleton 300. [0093] Figure 13 schematically illustrates the pivot axis 1201 of the left ankle pivot connection 318. Figure 13 shows a schematic diagram of the pivot axis 1201. The support plane 310 of the left foot structure 308 is shown schematically in this figure. A plane 1202 perpendicular to the median longitudinal axis 901 of the support plane 310 is also shown. An arrow represents the direction of the walk. The pivot axis 1201 of the left ankle pivot connection 318 has an angle 13 in a range of 0 ° to 30 ° relative to the support plane 310 of the foot structure. The pivot axis 1201 has an angle α in a range of 0 ° to 45 ° with respect to a plane 1202 perpendicular to the median longitudinal axis 901 of the support plane 310. Either range of angles can also have a lower lower limit, for example, one or a few degrees. By presenting this pivot axis 1201, which is oblique, the left anklet pivot connection 318 enables the exoskeleton 300 to produce movements that are close to natural movements at the level of a human ankle, in particular movements that are the most frequent and important. A human ankle, as well as a hindfoot, is a biomechanics of relatively high complexity. This biomechanics has several degrees of freedom, especially in the tibio-tarsal, sub-astragalian and Chopart joints. These degrees of freedom play important roles in locomotion and balancing processes of a human being. The particular orientation of the pivot axis 1201 adds an offset in a medio-lateral direction to an inclination of the left leg structure 302 in a postero-anterior direction, and vice versa. More specifically, an inclination of the left leg structure 302 in a "positive" direction towards the front, is accompanied by a relatively small lateral offset of this structure with respect to the median longitudinal axis 901 of the structure. left foot 308. This offset is therefore oriented outwards. Conversely, an inclination of the left leg structure 302 in a "negative" backward direction is accompanied by an inward offset relative to the median longitudinal axis of the left foot structure 308. This offset, which is oriented inward, may be more important than the outward facing offset. The offset in the medio-lateral direction, thanks to the particular orientation of the pivot axis 1201 of the left ankle pivot connection 318, allows a transfer of the weight of the body to a support foot. This is in connection with movements of the basin structure 301, described above, which can also contribute to this weight transfer. The transfer of weight occurs during the start of a step, but also in steady state of walking, and stabilization in standing position. Furthermore, during walking, during a propulsion there is a phase where the left ankle pivot connection 318 is in plantar flexion and where the foot structure is folded in two at the foot pivot connection 905. Thanks to the particular orientation of the pivot axis 1201, a lateral translation of the center of gravity can then operate from one foot to the other. The left ankle pivot connection 318 thus effectively replaces the relatively complex biomechanics of the human ankle and the human hind foot. The left ankle pivot connection 318 is a relatively simple, compact and reliable system. However, this system allows movements approaching the important movements that biomechanics performs during a walking process, or during a stabilization process. The description of the left ankle pivot connection 318 in the foregoing applies mutatis mutandis to the right ankle pivot connection 319. [0099] Referring again to FIG. 5, the exoskeleton processor 514 may be programmed to perform multiple control modes. That is, the processor 514 may comprise a program, i.e., a set of executable instructions, defining a plurality of control modes. For example, a stabilization control mode may be provided to keep the person carrying the exoskeleton in a rest position. A walk control mode may be provided to assist the person carrying the exoskeleton to walk. Other modes of control may be provided for, for example, climbing steps, down steps, sitting on a chair, and getting up from a chair. In all these control modes, the processor 514 controls at least a portion of the actuators described above, thereby causing movements of the exoskeleton 300. [cm 00] The program may also allow the processor 514 to select a mode of control, and perform, based on the detection signals from the detector 510 and, more specifically, the inertial sensors 511, 512, 513. The exoskeleton 300 may be provided with other sensors that can transmit useful information to the sensor. processor 514 to perform the selected control mode. For example, one or more sensors capable of detecting obstacles may be provided on the left foot structure 308 and on the right foot structure 309. These sensors, which may be optical, are thus able to detect, for example, a walk or stairs. Such a sensor could also detect a distance with respect to an obstacle and communicate this information to the processor 514. [00101] A selection of a control mode and its implementation can be based on a dynamic parameter of the bust 109 of the person , illustrated in Figure 1, carrying the exoskeleton. The inertial sensors can detect such a parameter and communicate information relating to the parameter in question to the processor 514. Thus, the processor 514 can select a control mode, and implement it, from a movement speed of the bust 109 or from an acceleration of the bust 109, as measured. In another embodiment, the processor 514 can determine a position of a center of gravity from sensing signals from the inertial sensors. The processor 514 selects a control mode, and implements it, from this center of gravity. [00102] Fig. 14 illustrates a projection plane 1400 for control mode selection. The processor 514 projects in this plane 1400 the center of gravity G established from the information coming from the detector 510. The projection plane 1400 comprises different zones 1401 to 1410. Different control modes are respectively associated with the various zones 1401 to 1410. The processor 514 applies a control mode associated with an area in which the center of gravity G is located. [00103] The projection plane 1400 comprises a central zone 1401. This central zone 1401 is associated with a static stabilization mode. In this mode, the processor 514 stabilizes the exoskeleton 300 statically by keeping the two foot structures 308, 309 on the ground. The processor 514 responds to a disturbance at the bust 109 by forcing the exoskeleton 300 to perform one or more appropriate compensatory movements. For example, if the person carrying the exoskeleton leans slightly backwards, the processor 514 could cause flexion of the exoskeleton 300 at the knee pivot links 316, 317 to return the center of gravity G forward to the center of a support polygon. The projection plane 1400 includes a walking zone 1402 associated with a normal operating mode. In order to activate the normal operating mode, the person carrying the exoskeleton must lean sufficiently forward so that the center of gravity G therefore exits the central zone 1401 and enters the normal walking zone 1402. The exoskeleton 300 starts to walk forward and stops if the person stands up. [00105] The plan also includes emergency stabilization zones. If the user is too leaning forward, the center of gravity enters an earlier emergency stabilization zone 1403. The processor 514 causes the exoskeleton 300 to take a big step forward in order to stabilize. A left lateral emergency stabilization zone 1404 is provided for imbalance on a left side. The processor 514 causes the exoskeleton 300 to take a lateral step on its left side. Likewise, a right side emergency stabilization zone 1405 is provided for imbalance on a right side. The processor 514 causes the exoskeleton 300 to take a lateral step on its right side. Finally, a posterior emergency stabilization zone 1406 is provided for rearward imbalance. The processor 514 causes the exoskeleton 300 to step backward to regain its balance. The plane also includes turning zones: an area to turn left 1407 and an area to turn right 1408, especially during a walking process. The plan may also include zones to deviate: an area to deviate to the left 1409, and an area to deviate to the right 1410. [00107] NOTES [00108] The detailed description that has just been made in reference to the drawings is only an illustration of some embodiments of the invention. The invention can be realized in many different ways. In order to illustrate this, some alternatives are indicated briefly. The invention can be applied in many types of exoskeleton. For example, the invention may be applied in an exoskeleton that includes only one leg structure, with a single foot structure. An exoskeleton according to the invention may comprise a number of actuators lower, or higher, than the number of actuators in the embodiments described in detail with reference to the drawings. For example, other embodiments can be achieved by removing an actuator associated with a pivot link. That is, a pivot link does not have to be actuated, but can be free. In addition, other embodiments can be achieved by removing or adding pivot links, as well as other elements. An alternative embodiment may be simpler or more elaborate than those described, by way of example, in the foregoing. A basin structure according to the invention can be made in different ways. The detailed description shows an example in which the pond structure 301 comprises only one actuator 407 with locking devices 408, 409. In another embodiment, a pond structure may comprise two actuators: an actuator for a left basin pivot connection, and another actuator for a right basin pivot connection.

Such a pond structure does not require a blocking device. pool A control of an exoskeleton according to the invention can be realized in many different ways. For example, in the case where a command involves a determination of a center of gravity, the control may vary depending on a position of the center of gravity in a three-dimensional space, a volume. A control can also be based on a speed of displacement of the center of gravity, or an acceleration. The term "processor" must be interpreted broadly. This term embraces any type of device that can produce one or more output signals from one or more input signals, in particular to perform a control function. The term "pivot connection" can be understood as defined in solid mechanics. The foregoing remarks show that the detailed description with reference to the figures, illustrates the invention rather than limit it. The reference signs are in no way limiting. The verbs "understand" and "include" do not exclude the presence of other elements or steps other than those listed in the claims.

Claims (15)

REVENDICATIONS1. An exoskeleton (300) comprising: a leg structure (302) arranged to mingle with a leg (101) of a person carrying the exoskeleton having a foot (107) and ankle (105) to that leg, - a foot structure (308) comprising a support plane (310) on which the foot can bear when the foot is flat, the support plane having a median longitudinal axis (901), - an ankle pivot connection (318) connecting the structure foot to the leg structure, characterized in that the ankle pivot connection has a pivot axis (1201) having: - an angle (13) in a range of 0 ° to 30 ° relative to the support plane of the foot structure, and an angle (a) in a range of 0 ° to 45 ° with respect to a plane perpendicular to the median longitudinal axis of the support plane. An exoskeleton according to claim 1 comprising an actuating device disposed between the leg structure (302) and the foot structure (308) to cause pivoting of the foot structure relative to the leg structure along the axis. pivoting (1201) the ankle pivot link (318). The exoskeleton according to claim 2, wherein the actuating device comprises: a cardan joint (1202), a ball joint (1203), and an actuator (1204) disposed between the cardan joint and the ball joint . An exoskeleton according to any one of claims 1 to 3, wherein the support plane (310) of the foot structure (308) comprises: - a front platform (903) and a rear platform (904) ), the rear platform being connected to the ankle pivot connection (318), and a foot pivot connection (905) connecting the front platform to the rear platform. An exoskeleton according to claim 4, wherein the foot pivot connection (905) comprises an elastically deformable member (906) arranged to store energy when the front platform (903) is folded relative to the platform. rear shape (904). An exoskeleton according to any one of claims 4 and 5, wherein the foot pivot connection (905) is in a quadrant delimited by a medial sagittal section (113) of the person carrying the exoskeleton and a frontal cut ( 115) passing through the leg, the foot pivot connection having a pivot axis (1101) defining a right triangle in the same quadrant and having an angle (1102) in a range of 45 ° to 90 ° with respect to the cross section. sagittal median. The exoskeleton according to claim 6, wherein the rear platform (904) is closer to the medial sagittal section (113) than the front platform (903), so that the median longitudinal axis (901) the support plane (310) has an angle between 0 ° and 45 ° with respect to the median sagittal section (113) when the exoskeleton is in the rest position. The exoskeleton according to any one of claims 1 to 7, wherein the leg structure (302) comprises: an upper leg segment (304) disposed to mate with an upper leg portion (101) lying above one knee (103) of the person carrying the exoskeleton, a lower leg segment (305) arranged to co-operate with a lower leg below the knee, and a pivot connecting knee (316) connecting the lower leg segment to the upper leg segment, the upper leg segment having an inclination (801) in a range of 0 ° to 30 ° relative to the lower leg segment when the exoskeleton is in the rest position, such that an upper end (802) of the upper leg segment is further away from a medial sagittal section (113) of the person carrying the exoskeleton than a lower end (803). An exoskeleton according to any one of claims 1 to 8, comprising: a pelvis structure (301) arranged to be attached to the pelvis (110) of the person carrying the exoskeleton, a leg-orientation pivot connection (410) disposed between the pelvis structure and the leg structure (302), the leg orientation pivot connection having a vertical pivot axis when the exoskeleton is in the rest position. 10. Exoskeleton according to any one of claims 1 to 9, comprising a control device (501) adapted to control at least one actuator (407, 412, 413, 326, 329-333) included in the exoskeleton. An exoskeleton according to claim 10, wherein the control device (501) comprises: a detector (510) adapted to detect at least one dynamic parameter of at least a portion of the bust (109) of the person carrying the exoskeleton , and a processor (514) adapted to apply a control signal to an actuator (407, 412, 413, 326, 329-333) according to a detected parameter. The exoskeleton according to claim 11, wherein the detector (510) comprises at least one inertial sensor (511-513). A method for controlling an exoskeleton according to any of claims 11 and 12, wherein the processor (514) is adapted to perform a plurality of control modes, including: a stabilization control mode in which the processor controls at least one actuator (407, 412, 413, 326, 329-333) for holding the person carrying the exoskeleton in a rest position, a gait control mode in which the processor controls at least one actuator to assist the person wearing the exoskeleton to walk. The method of claim 13, wherein the processor (514) is adapted to determine a position of a center of gravity (G) of at least a portion of the body of the person carrying the exoskeleton and to apply a mode control depending on the position of the center of gravity. 15. The method of claim 14, wherein the processor is adapted to associate different control modes respectively to different areas (14011410) in a plane (1400) on which the center of gravity (G) is projected, the processor being adapted to apply a control mode associated with an area in which the center of gravity is located.