FR3110389A1 - DEFORMABLE ARTICULATION MOVEMENT ASSISTANCE STRUCTURE AND CORRESPONDING PROCESS - Google Patents

Abstract

This is a structure, a device or exoskeleton and a method of use by a user of an exoskeleton comprising at least one deformable structure (1) to aid in the articulation movement of a user body element. The structure comprises an elongated chain (2) of identical or substantially identical elements (3) rigidly fixed on one side (4) on a flexible support (5) and linked together on the other side in a sliding manner by a cable. (6), said cable being fixed at one of its ends to a distal element (8) of the chain and arranged to be fixed at its other end (9) to means for pulling on the cable, said structure further comprising means for fixing the flexible support on either side of the articulation of said element. Figure for the abstract: Fig. 2

Description

DEFORMABLE STRUCTURE FOR AIDING ARTICULATION MOVEMENT AND CORRESPONDING METHOD

The present invention relates to deformable structures and more particularly those usable in the field of exoskeletons, making it possible to aid the articulation movement of an element of the body of a user by allowing the relief of the stresses undergone by this element (his knee , his neck, his spine, etc.), for example when the user moves loads.

These are mechatronic systems whose movements are controlled by those of the user and which make it possible to limit the forces exerted on said joints, such as those of the vertebrae, in particular the lumbar vertebrae of the user.

They can be used alone or in combination with more complete complementary exoskeleton structures making it possible to handle heavy parts or even to assist the gesture of an operator during a painful and repetitive task, requiring at least partial and repeated bending of the back. and/or knees and/or ankles etc.

It also relates to an exoskeleton implementing one or more deformable structures of this type.

It also relates to a method of using such exoskeletons.

Deformation actuator devices based on deformable polymers are known. Pressure is exerted which will deform one side of the device rather than the other, causing the actuator to bend under the effect of the pressure.

This solution has drawbacks. Indeed if it allows to be motor in the direction of the bent position (curved) towards the straight position (flat), it does not allow assistance in the other direction. However, it is often necessary to be able to be a motor in the other direction as well.

For the knee, for example, the weight to sit on is also a constraint to be managed. If we want to assist the movement by relieving the user when he sits down, we will therefore have to slow down the movement of the joint and be a motor in the direction of the flat towards the curve.

For the ankle, in the context of walking or running, it is necessary to give an impulse against gravity which will be, here again, from the curve towards the flat, but also from the flat towards the curve.

There are also known exoskeletons provided with motor means helping the rotation of the joint by rotary drive in one direction or braking in the other.

But this requires expensive and complex motors to control, in complete synchronization with the movements of the user, motors which can even sometimes be counterproductive because they can be able to thwart the movements of the latter if it is too abrupt in his move.

The object of the invention is to overcome these drawbacks by providing a deformable structure, an exoskeleton comprising such a structure and a method of using such an exoskeleton that responds better than those previously known to the requirements of practice, in particular by making it possible to provide effectively assisting with tensioning/relaxation and/or extension/bending efforts of a user's joint, while being robust and of reasonable cost.

The structure according to the invention will make it possible to effectively provide assistance in the operation of a joint, while adapting easily and/or automatically to all morphologies and to all positions thereof. The user has an excellent feeling of comfort while minimizing the risk of musculoskeletal disorders and fatigue.

For this purpose, the present invention proposes in particular a deformable structure for assisting the movement of articulation of an element of the body of a user, comprising a slender chain of identical elements rigidly fixed on one side to a flexible support and connected between them on the other side in a sliding manner by a cable, said cable being fixed at one of its ends to a distal element of said chain and arranged to be fixed at its other end to traction means on said cable, said structure further comprising means for fixing the flexible support on either side of the articulation of said element.

In advantageous embodiments, one and/or the other of the following provisions is also and/or additionally used:
- the identical elements of the chain are T-shaped parts whose feet are fixed on the flexible support and whose bars are tubular and arranged to allow the cable to pass, in a sliding manner;
- the flexible support is a strip with a width of between 2 cm and 10 cm;
- the flexible support and the elements are made of flexible plastic material (for example in thin PTFE, < 1mmn or even 0.5 mm).

The invention also proposes an exoskeleton comprising at least one deformable structure as described above, characterized in that it comprises traction means on the cable, means for detecting the movements of the joint and control means traction or relaxation on the cable depending on the bending or straightening of said joint.

Advantageously, the cable traction means comprise a cylinder or a rotary motor.

In an advantageous embodiment, the element of the user's body is the user's knee, the deformable structure being arranged to be actuated or released by the differential traction of the cable to help straighten or bend the knee.

Also advantageously, the element of the user's body is the user's neck, the deformable structure being arranged to be actuated or released by the differential traction of the cable to help straighten the head.

Again advantageously, the element of the user's body is the user's spine, the deformable structure being arranged to be actuated or released by the differential traction of the cable to help straighten the back.

Advantageously means for detecting the intention of movement of the user are provided.

The detection means are for example formed by a strain gauge sensor of known type, suitably installed and/or programmed in a manner known per se.

Threshold values can also be provided to avoid false orders and/or handling errors due to excessively sudden movements by the user.

The invention also proposes a method for implementing the exoskeleton, as described above.

It also proposes a method of use by a user of an exoskeleton to aid in the articulation of an element of the body of said user, comprising:
- a step of removably attaching the exoskeleton to the element of the user's body by attaching, on either side of the articulation of the element of the user's body, a deformable structure for assisting the movement of said articulation, said structure comprising an elongated chain of identical elements fixed rigidly on one side to a flexible support and interconnected on the other side in a sliding manner by a cable, said cable being fixed to one of its ends to a distal element of said chain and fixed at its other end to traction means on said cable,
- a step of bending said joint of the user and/or a step of unfolding said joint in an assisted manner, by simultaneous actuation with bending or unfolding of the actuator in traction on the cable, with transmission of the tension by said cable to stiffen or loosen the chain of identical elements.

Advantageously, the intention of movement of the user is detected, for example by a strain gauge sensor of known type, suitably installed and/or programmed, so as to actuate the cable or release it in anticipation of the movement.

The invention will be better understood on reading the following description of embodiments given below by way of non-limiting examples and which will be made with regard to the accompanying drawings in which:

illustrates the operating principle of the deformable structure according to one embodiment of the invention.

is a schematic perspective view of a user provided with an exoskeleton implementing a deformable structure according to a first embodiment of the invention applied to the knee.

is a schematic and partial rear view of an exoskeleton illustrating a second embodiment of a structure according to the invention applied to the back of a user.

is a schematic side view of the embodiment of Figure 3.

shows a schematic side view showing four possible applications of the structure according to the invention on the joints of a user.

is a schematic front view of an operator provided with an exoskeleton according to another more complete embodiment of the invention, provided with four deformable structures according to the embodiment of the invention more particularly described here, two for the back and two for the knees.

is a partial rear view illustrating an embodiment of the means for tensioning the cable or the loop of the cable for tensioning the deformable structure according to the invention.

Figure 1 shows the principle of a deformable structure 1 according to one embodiment of the invention. This structure can be provided alone or in combination with any other exoskeleton element allowing movement assistance for an operator who has to bend down and get up regularly with a load, for example an exoskeleton comprising a dorsal structure like the one that will be described below with reference to Figure 6.

The principle consists in using a slender chain 2 of identical or substantially identical elements 3 (see for one or more of them different but nevertheless having the same functional characteristics) rigidly fixed on one side 4 to a flexible support 5 and interconnected on the other side in a sliding manner by a cable 6 passing through a channel 7 located in the upper part of the identical elements on the side opposite the support.

The cable 6 is fixed on one side to a distal element 8 of the chain and is arranged to be fixed on the other side 9 to traction means (not shown) of types known per se (piston or differential screw by example).

When the cable is pulled, the ends facing the elements are arranged to come into abutment against each other and rigidly block the chain by contact in compression against each other, which makes the Rigid chain capable of absorbing the stresses.

Such a device therefore makes it possible to effectively provide assistance with tensioning, releasing and/or extending/bending efforts of a user's joint, while being robust and at a reasonable cost.

The flexibility of the support and the ease of use of the structure allow excellent, easy and automatic adaptation to all body shapes and all operator positions.

Here the identical elements 3 of the chain 2 are T-shaped parts whose feet 10 are fixed on the flexible support 5 and whose other ends 11 (the bars of the Ts) are in the form of a tubular bar hollowed out by a central bore longitudinal (in the direction of the bar) arranged to allow the cable to pass in a slippery manner.

During traction, the ends of the adjacent T bars come into abutment against each other, which makes the chain of the structure rigid.

The flexible support, for example a strip of width between 2 cm and 10 cm, made of soft and flexible material, is itself arranged to adapt to the movement of the joint, and is for example made of thin plastic material. e (e < 1mm) of the PTFE type, or rubber or equivalent.

FIG. 2 shows a device or exoskeleton 12 on the knee G of a user and/or operator U, comprising a structure 13 implementing the principle described above, comprising a support strip 14, the chain 15, the cable 16 passing through upper parts 17 in the form of a T bar and traction means 18 comprising a rotary motor 19 and a screw 20.

The motor is controlled by means 21 for detecting the movements of the joint and the movement intentions of the operator.

The device also comprises means of attachment to the user's thigh and ankle, in a manner known per se, for example by flexible bands 22 and 23 respectively.

Figures 3 and 4 schematically show the application of the above principle to the lumbar vertebrae of a user 24.

In this non-limiting embodiment and so as to allow balanced stress on the lower back during the user's movements, two symmetrical chains 25 and 26 are provided spaced apart from each other to allow attachment on one side. to the body of the user in the upper part above each of the buttocks, and a clip on the other side in the lower part under each thigh of the user.

In this embodiment, the two structures use the same cable 27, the central loop of which passes through the pulley P, which makes it possible to exert balanced stresses on the thighs, taking into account any torsion of the torso and/or the back of the the user, allowing him to pick up loads that are offset from his work axis.

When it is pulled on the cable 27, symmetrically or asymmetrically at 28 and 29, the chains 25 and 26 are stiffened or relieved, which has the effect of straightening the back (arrow 30), straightening the thighs ( arrow 31), and in doing so assist in the effortless recovery of the user's back, in particular when lifting the load by the latter.

Means 32 and 33, for fixing the chains respectively on the back and on the thighs of the user are provided in a manner known per se.

There is shown in Figure 5, the application of such chains to the different joints of the same user, who will thus be able to relieve his joints at the level of the cervical vertebrae (34), the lumbar vertebrae (35), the knee joints (36) and/or pins (37), and this with traction actuator means formed for example by small rotary electric motors (38) driving in rotation a ball screw 39 with nut 40 generating a longitudinal traction force T , thus avoiding a more bulky piston-type actuator.

A traction system by displacement of a tractor carriage as described with reference to FIG. 7 is for example usable and/or as described in document US 2016288319, with anti-rotation device.

Figure 6 shows an exoskeleton 41 comprising an axial dorsal structure 42 (in broken lines) removably attachable to the shoulders 43 of an operator 44, in a manner known per se by straps 45.

The back structure 42, axial or elongated around an axis 42 ', is equipped with an actuator 46, for example an electric vertical piston 47 arranged to exert a vertical traction (arrow 48) on a central pulley P via a cable 49 , for example metallic, for connection and differential tensioning of the two side equipment 50 and 51, symmetrical with respect to the axial back structure 42.

Each side equipment 50 and 51 is respectively provided with means 52 for removable attachment to the thighs 53 of the user or operator 44.

These means are formed of parts or straps in the form of a hook, suitable for resting on the back and on the front of the thigh, with which they are made integral for example by a frontal strap, allowing an adjustable and adjusted fixing to the volume of the thigh.

In the embodiment more particularly described here, the axial dorsal structure 42 further comprises a lower part in the form of a widened strip 54, adjustable to the size of the operator by means of a belt 55 for attaching the ends of the shoulder straps .

The back structure and the side equipment 50 and 51 are also interconnected by means of the cable 49 via an intermediate connecting piece (not shown) arranged to be kept at a distance from the user's lower back, for example thanks to a lateral offset and/or in a suitable shape, protruding from the back of the user, and by the upper part of the back structure, for example curved towards the shoulders 43 of the user.

In the embodiment of Figure 6, the pulling force of the cable 49, is exerted by the movement of the central pulley P movable in translation vis-à-vis the back structure 42 and the side equipment 50 and 51.

The pulley P is arranged to transmit the differential tension (arrow 56) to the side equipment by the cable 49, to pull or release in a balanced manner on the thighs of the user via the means 52 for fixing to the thighs.

In the embodiment of Figure 1 the exoskeleton 41 further comprises two deformable structures 57 (schematically shown), of the type described with reference to Figure 2, actuated or released by the differential traction of a cable 58, aid in straightening the knee, using an actuator 59.

There is shown with reference to Figure 7 another embodiment of actuation of the central pulley at the level of the central loop B of the differential tensioning cable.

Here the system comprises a differential carriage 60 which moves vertically (arrow 61) along an axis 42'', parallel to the axis 42' of the back structure 42, the central pulley P being of vertical axis 42 ''.

The pulley comprises a nut 62 mounted on a ball bearing 63 which rotates around a screw (not shown) actuated in rotation by a rotary motor (not shown) in a manner known per se, allowing the vertical movement of the carriage 60.

Two side pulleys 64 return the cable vertically to structures 50 and 51.

Finally, the deformable structure or structures comprise, alone or in combination, detector means 80 fixed to the structure and/or an adjacent structure to detect the pitching movement with respect to gravity during the recovery or the announcement of the vertical recovery of the structure by the operator.

In the case of the exoskeleton comprising two structures interconnected by the same cable to relieve the lumbar vertebrae, it also advantageously comprises means 65 for calculating the motor torque of the actuator as a function of the sine of the pitch angle resulting detector means 66.

These means comprise for example an accelerometer and potentiometers 67 each associated with a hip of the operator and arranged to be activated at the same time to inform the calculation means of the pitch angle from the detector means.

Advantageously, the exoskeleton further comprises means 68 for detecting the intention and/or the movement of the operator comprising a strain gauge sensor of known type, suitably installed and/or programmed, for example communicating via wi-fi with the means of calculation and placed on the thighs and where the feet of the operator (not shown).

We will now describe the operation of the structures of the exoskeleton by a user with reference to FIG. 6, applied to the back and to the two knees.

But it goes without saying that the installation and operation will take place in a similar way in the case of the other applications envisaged.

Operator 4 first puts the two structures in place on his thighs and his corresponding ankles, and attaches the straps. He then puts the rest of the exoskeleton on his shoulders and attaches the straps and the belt.

He then initializes the computer and the inertial unit and then positions himself to move the load and/or perform the task assigned to him and which requires the reinforcement.

To do this, he bends his knees and/or leans forward, for example to grab a load. As soon as he bends his knees (use of the potentiometers on the hips and/or bends the thorax (use of an inertial unit, to recover the pitch, the unit being arranged in a way known in itself to transmit its orientation with respect to the direction of earth's gravity through a rotation matrix), the help structure comes into play.

In fact, as soon as they begin to move even a few millimeters, to change their attitude, and/or to bend down and pick up the object, the exoskeleton releases the cable to give it the necessary flexibility, the load is then gripped then as the operator initiates the ascent movement the exoskeleton reacts and by making the central point of the loop go up but in tension the pulley P, and the cables of the knees to help and relieve the straightening of the joints.

The inertial unit and/or the potentiometers are informed of the pitch and adapt the pulling forces on the cables to allow the operator to stand up effortlessly with the load.

He can then move without difficulty and in particular without being encumbered, to replace the load at the place of his destination by using the exoskeleton in a symmetrical way to limit this time the efforts on these lumbar and the joints of his hips and /or his knees as described above.

As goes without saying and as results moreover from the foregoing, the present invention is not limited to the embodiments more particularly described but on the contrary embraces all the variants thereof and in particular those where the rest of the exoskeleton associated with the deformable structures according to the invention are of different compositions, known to those skilled in the art.

Claims (11)

Deformable structure (1) for aiding the articulation movement of an element of a user's body, comprising a longilinear chain (2) of identical or substantially identical elements (3) rigidly fixed on one side (4) on a flexible support (5) and interconnected on the other side in a sliding manner by a cable (6), said cable being fixed at one of its ends to a distal element (8) of said chain and arranged to be fixed at its other end (9) to traction means on said cable, said structure further comprising means for fixing the flexible support on either side of the articulation of said element. Structure (1) according to Claim 1, characterized in that the elements (3) of the chain are T-shaped parts whose feet (10) are fixed to the flexible support (5) and whose bars are tubular and arranged to allow the cable to pass in a slippery manner. Structure (1) according to any one of the preceding claims, characterized in that the flexible support (5) is a strip with a width of between 2 cm and 10 cm. Structure (1) according to any one of the preceding claims, characterized in that the flexible support and the elements are made of flexible plastic material. Exoskeleton (12, 41) for aiding the articulation or movement of an element of a user's body, comprising at least one deformable structure (13) according to any one of the preceding claims, characterized in that it comprises means (18) for traction on the cable, means for detecting the movements of the articulation and means for controlling the traction or the release on the cable according to the bending or straightening of the said articulation. Exoskeleton according to Claim 5, characterized in that the element of the user's body is the user's knee, the deformable structure being arranged to be actuated or released by the differential traction of the cable to aid in straightening or bending of the knee. Exoskeleton according to Claim 5, characterized in that the element of the user's body is the user's neck, the deformable structure being arranged to be actuated or released by the differential traction of the cable to help straighten the head . Exoskeleton according to Claim 5, characterized in that the element of the user's body is the spine of the user, the deformable structure being arranged to be actuated or released by the differential traction of the cable to help straighten the back . Exoskeleton according to any one of Claims 5 to 8, characterized in that it includes means for detecting the intention of movement of the user with threshold values to avoid false orders and/or handling errors due to too sudden movements of the user. Method of use by a user of an exoskeleton for assisting the articulation of an element of the body of said user, comprising
- a step of removably attaching the exoskeleton to the element of the user's body by attaching, on either side of the articulation of the element of the user's body, a deformable structure movement aid for said articulation, comprising a longilinear chain of identical elements fixed rigidly on one side to a flexible support and interconnected on the other side in a sliding manner by a cable, said cable being fixed to one of its ends to a distal element of said chain and fixed at its other end to traction means on said cable,
- a step of bending said joint of the user and/or a step of unfolding said joint in an assisted manner, by simultaneous actuation with bending or unfolding of the actuator in traction on the cable, with transmission of the tension by said cable to stiffen or loosen the chain of identical elements. Method according to claim 10, characterized in that the intention of movement of the user is detected so as to actuate the cable or release it in anticipation of the movement.