EP0088035A1 - Motorized walking-aid - Google Patents

Abstract

The subject of the invention is active walkers intended for learning and rehabilitating motor skills. A walker according to the invention comprises a self-propelled chassis (1) mounted on wheels (2, 3) of which at least one is motorized. It comprises a nacelle (10), which is fixed to a mobile support (6) and in which takes place a patient whose feet touch the ground. The mobile support (6) is suspended from the chassis (1) by articulated connecting rods (7) which allow relative movement of the support relative to the chassis in the longitudinal direction. A sensor (12) connects a link to the chassis and emits an electrical signal proportional to the longitudinal displacement. The motor (4) which drives the driving wheel (3) is incorporated in a servo loop controlled by the signal delivered by the sensor (12). One application is gait rehabilitation in individuals with motor impairment.

Description

The invention relates to active walker devices intended for education or for re-education of walking.

The technical sector of the invention is that of the construction of self-propelled devices intended to develop, restore or revive the powers of locomotion of children or the disabled.

Education or rehabilitation of motor skills can be obtained by placing an individual in an artificial environment, for example in the water of a swimming pool, which lightens the weight and which facilitates movements.

Exercise machines, such as bicycles, are also used by which the patient trains to develop and rehabilitate certain muscles and elements of the locomotor system or non-motorized walkers on which the subject rests and which he move with him. These devices require muscular strength and a good balance of the subject.

There are also known wheelchairs or passive motorized walkers which facilitate the movement of the disabled between rehabilitation sessions, but who do not participate in learning to walk.

A disadvantage of known exercise devices and apparatuses resides in the fact that they are used only during the duration of the rehabilitation sessions, that is to say for a limited time and in an environment distinct from that in which lives usually the subject, which reduces their effectiveness. In addition, they do not allow the subject to access the experience of walking, that is to say the proprioceptive feeling of walking. Finally, they require a conscious and active participation of the subject. In the case of young children with motor impairment due to mental deficiencies, it is not always possible to obtain their active participation during the rehabilitation sessions.

Known passive motorized walkers, which are intended for subjects who have very low motor skills, leave them entirely inactive, which reinforces their passivity and their immobility.

It is an object of the present invention to provide. active walker devices which remedy the drawbacks of known methods and apparatus.

• - qui mettent en jeu tout ou partie du système locomoteur;
• - qui peuvent fonctionner dans le milieu de vie du sujet soit en milieu hospitalier, soit à domicile;
• - qui peuvent être utilisés de manière prolongée et continue sans fatiguer le sujet et qui amplifient et développent les plus faibles possibilités locomotrices de celui-ci;
• - qui permettent de graduer les forces d'appui au sol et le degré de participation active du sujet:
• - qui permettent de passer, de manière progressive, d'une fonction de rééducation active à une fonction de transport plus passive, ces deux fonctions pouvant être associées diversement.

Another objective of the invention is to provide active walking devices:

• - which involve all or part of the locomotor system;
• - which can operate in the subject's living environment either in hospital or at home;
• - which can be used in a prolonged and continuous way without tiring the subject and which amplify and develop the weakest locomotor possibilities of this one;
• - which allow graduation of the ground support forces and the degree of active participation of the subject:
• - which make it possible to progressively move from an active rehabilitation function to a more passive transport function, these two functions being able to be combined in various ways.

Another objective of the invention is to provide active walker devices which make it possible to accelerate, in retarded children, learning to walk and the crossing of this stage of which everyone recognizes the importance and the effect of threshold for their further development.

The active walkers according to the invention comprise, in known manner, a self-propelled chassis mounted on wheels, at least one of which is a driving wheel, driven by a motor, and it also comprises a nacelle in which a subject takes place, which has holes for the passage of the legs and which is supported by the frame at a height such that the subject's feet touch the ground.

The objectives of the invention are achieved by means of walkers which are characterized in that said nacelle is fixed on a mobile support which is connected to said self-propelled chassis by connecting means which allow it to move freely relative to said chassis in at at least one direction, that said movable support is connected to said chassis by at least one sensor which emits an electrical signal proportional to one of the components of the relative movement of said support with respect to said chassis and that it includes control loops, which connect each of said sensors to one of said motors and which automatically control said motors to move said chassis with a movement which corresponds, in direction e: in intersity, to the relative movement of said .support with respect to said t chéssis.

According to a preferred embodiment, the self-propelled chassis has a generally rectangular shape and comprises four uprights of vertical angles, said movable support also has a generally rectangular shape plus.petite whose sides are internal those of said chassis and it is suspended from said uprights by four suspension members; the lower end of at least one of these suspension members is connected to said chassis by a linear displacement sensor, which emits an electrical signal proportional to the component of the relative displacement of said lower end relative to said chassis which is parallel to the longitudinal axis of the chassis, said chassis comprises as many motorized wheels as there are sensors, which wheels are driven by a geared motor group and each motor is connected to one of the sensors by a servo loop which automatically controls said motor in the direction which cancels the signal emitted by said sensor.

The invention results in new active walker devices which make it possible to very effectively correct motor skills deficiencies in children or in accident victims.

Experiments carried out on prototypes have shown that the walkers according to the invention very effectively facilitate learning or rehabilitation of motor skills. Indeed the weight of the body is supported by the nacelle which relieves the patient as much. In addition, the platform support which is suspended from the self-propelled chassis or which rolls therefrom without friction, moves at the slightest request from the subject and immediately the self-propelled chassis follows without requiring any muscular effort. As a result, the patient sees his least drafts of movements followed by displacement, which prompts him to continue.

In particular in children suffering from motor disturbances due to psychic inhibition, the active walkers according to the invention make it possible to restore the confidence of the child who becomes aware of his possibilities and very quickly the inhibition is eliminated.

The walkers according to the invention comprise means such as connecting rods, bending blades, springs, which constitute a more or less rigid mechanical connection. between the mobile support of the nacelle and the self-propelled chassis. The coefficient of elasticity or the modulus of this connection can be varied in order to gradually dose the muscular efforts required of the patient as he progresses.

• - l'accélération du franchissement de l'étape de la marche chez les enfants retardés qui a un effet de seuil pour le développement ultérieur;
• - l'accélération de la rééducation de la motricité après un traumatisme osseux ou musculaire chez l'enfant ou chez l'adulte;
• - l'amélioration de la restauration fonctionnelle de la motricité après des lésions nerveuses.

Among the possible applications of walkers according to the invention, we quote:

• - the acceleration of the crossing of the step of walking in retarded children which has a threshold effect for further development;
• - acceleration of motor skills rehabilitation after bone or muscle trauma in children or adults;
• - improving functional restoration of motor skills after nerve damage.

• Les figures 1 et 2 sont une vue de côté et une vue de l'arrière d'un premier mode de.réalisation.
• La figure 3 est une vue partielle à plus grande échelle du capteur des figures 1 et 2.
• Les figures 4 et 5 représentent une vue de côté et une vue de l'arrière d'un deuxième mode de réalisation.
• Les figures 6 et-7 représentent une vue de côté et une vue de l'arrière d'un troisième mode de réalisation.

The following description refers to the appended drawings which represent, without any limiting character, exemplary embodiments of active walkers according to the invention.

• Figures 1 and 2 are a side view and a rear view of a first mode de.réalisation.
• FIG. 3 is a partial view on a larger scale of the sensor of FIGS. 1 and 2.
• Figures 4 and 5 show a side view and a rear view of a second embodiment.
• Figures 6 and -7 show a side view and a rear view of a third embodiment.

Lès Figures 1 and 2 show an active walker which comprises a frame 1, for example a tubular frame of generally rectangular shape, which is mounted on 2 supporting and self-steering wheels, that is to say wheels which are mounted on a support pivoting about a vertical axis, the wheel axis being eccentric relative to said vertical axis. The chassis 1 further comprises a driving wheel 3; which is placed in the axis of the chassis. parallel to the direction of travel and whose axis is transverse to the chassis. The driving wheel 3 is driven by a geared motor group 4, the electric motor of which is a two-way motor, powered for example by an accumulator battery 5, carried by the chassis.

The chassis 1 is composed of four vertical uprights la, located at the four angles and connected to each other by side members lb and by cross members Ic ...

A mobile nacelle support 6, which is for example a rectangular tubular frame, smaller than the chassis 1, is suspended from the four uprights la by four connecting rods 7. The connecting rods 7 are located in vertical, longitudinal planes, that is to say ie parallel to the direction of travel. The upper end of each link is articulated to the chassis around a horizontal axis 8 and the lower end of each link is articulated around a horizontal axis 9. The axes 8 and 9 are transverse, that is to say perpendicular to the direction of travel and parallel to the axis of the motorized wheel 3 .

A nacelle 10 is suspended from the upper frame 6a of the support 6. The nacelle 10 is for example a canvas nacelle, in the shape of a panty, comprising two orifices 11 for the passage of the legs of a patient who takes place in the nacelle. The height of the basket support 6 is such that the patient's feet are supported on the ground. Thus, most of the patient's weight is supported by the nacelle 10 and transferred to the ground by the support .6, the links 7 and the chassis 1. However, thanks to the contact of his feet with the ground, the patient can take a light support on the ground and exert on the nacelle 10 a force which tends to move the nacelle relative to the frame 1 by rotating the four links around their axis 8 of suspension. One of the links is equipped with a sensor 12 which picks up one of the components of the relative movement of the support 6 with respect to the chassis 1 and which analogically converts the intensity of this component into an electrical signal, for example a voltage, proportional to the intensity of the measured component.

It is specified that the word movement is taken in a general sense and the word component of the movement indicates any vector which characterizes the relative movement and which can be the component in a determined direction of a linear or angular displacement, of a speed, d 'a force corresponding to an acceleration, or a couple.

Figures 1 and 2 show a simplest embodiment of an active walker used to stimulate walking in a straight line and in which, due to the suspension of the support 6 by the four links 7, the relative movement of the nacelle relative to the chassis is a movement with a single degree of freedom, in a rectilinear direction parallel to the longitudinal axis of the chassis.

FIG. 3 represents an elevation view of the sensor 12. The latter is composed of a rotary potentiometer 13 which is fixed to the chassis 1. It comprises a link 14 which connects the articulation 9 to the cursor 15 of the potentiometer which has a notch 15a, into which one end 14a of the connecting rod 14 enters. Thus the relative movement of the chassis 6 relative to the chassis 1 is transmitted by the link 14 to the rotary cursor 15 and the voltage emitted by the potentiometer varies, positively or negatively, around a reference value proportional to the pivot angle of the link 7. This tension is amplified.

A servo device receives the amplified voltage and automatically starts the motor 4 in the direction which cancels the difference between the voltage emitted and the reference voltage, which corresponds to an absolute displacement of the self-propelled chassis 1 relative to the ground. in the same direction and the same length as the relative movement of the nacelle relative to the chassis.

In this example where the relative movement of the nacelle relative to the chassis is a unidirectional movement, the self-propelled chassis 1 is equipped with a single motorized wheel located in the longitudinal axis which moves the self-propelled chassis in one direction.

It is understood that, because the nacelle support 6 is suspended by four links from the chassis 1, the slightest thrust that the patient will exert on the ground with his feet is enough to move the nacelle.

The joints 8 and 9 are frictionless joints, for example bearings. The drive wheel immediately moves the self-propelled chassis by an equivalent length without the patient having to spend any energy to obtain this displacement. In fact, the patient's efforts are multiplied and he, who perceives the result of his efforts is strongly encouraged to persevere, hence an effect of encouragement to the effort.

The device according to FIGS. 1 and 2 makes it possible to adjust the effort required of the patient as he progresses. In fact, when the nacelle support 6 leaves its stable equilibrium position, the patient's weight P exerts on the links a torque which recalls the links towards the equilibrium position and which is equal to P.ℓsinα, ℓ being the length of the link and the angle of rotation. By playing on the length of the links 7, it is possible to vary the restoring torque and force the patient, as he progresses, to make an increasingly greater effort, in order to obtain the same relative displacement.

When the patient is seated in the basket 10, his hands are placed substantially at the height of the upper frame 6 from which the basket is suspended. This frame 6a is placed above the upper end of the uprights 1 and sufficiently distant from them so that the patient cannot reach the uprights with his hands and exert a traction which would cause a relative displacement of the nacelle relative to the chassis and a connection between them, so that the self-propelled carriage 1 move with a continuous movement without the patient having to exert any effort with his feet. The cart would then behave like a self-propelled passive cart.

Figures 4 and 5 show another embodiment. The parts homologous to those of FIGS. 1 and 2 are represented by the same references.

The difference lies in the embodiment of the suspension of the support 6 and the relative movement sensors of the support 6 relative to the self-propelled chassis 1.

In this embodiment, the nacelle support 6 is suspended from the four uprights la by flexible hangers 16 which are for example flexible blades situated in transverse planes, so that when the support 6 exerts a force in the longitudinal direction on the blades 16, these bend in the longitudinal direction.

Strain gauges 17, of the strain gauge type, are bonded to the flexible blades 16 and they emit a reduction which is proportional to the flexion of the blades and therefore to the force which is exerted on them. According to a well-known assembly, a pair of strain gauges 17 is bonded to each face of the blade and these are mounted in the four sides of a resistance bridge, the two blades placed on the same face being mounted in series, and the current flowing in the diagonal of the bridge is proportional to the bending of the blade.

The electric signal which circulates in the diagonal of the bridge is amplified and it automatically controls the starting of the motor 4 in the direction which cancels the signal.

The embodiment according to Figures 4 and 5 is an active walker having two degrees of freedom, that is to say a walker which allows the patient to move in an oblique direction by pivoting.

In this case, two of the front or rear lines, for example the two front lines, are wires (18d, 18g) or flexible scalloped blades which allow freedom of movement of the nacelle support relative to the chassis in all directions. The other two lines, i.e. the rear lines are bending blades 16d, 16g, which are each equipped with a displacement sensor 17d, 18g and the chassis has two 3d, 3g motorized wheels located at the 'rear and symmetrical with respect to the longitudinal plane of symmetry. The motor 4d, 4g controlling each wheel is respectively controlled by the electrical signal delivered by the sensor located on the same side.

The pivoting of the nacelle support relative to the chassis causes a difference in the flexions of the two blades 16d, 16g carrying the sensors and this difference is found in the progressions of the two wheels 3d, 3g, so that the chassis advances by turning on it -Even at an angle equal to the pivot angle of the platform support and, at the end of movement, the chassis is aligned with the platform support and it has advanced in the same direction as the latter and by the same length.

In the embodiment according to FIGS. 4 and 5, when the nacelle support moves, the flexible blades 16 exert on it a push which tends to bring it back to the equilibrium position and the patient must exert an effort to overcome this thrust. By varying the length of the blades and their flexibility, for example by juxtaposing several flexion blades, it is possible to adjust the effort required of the patient to obtain the same displacement, so that it is possible to increase this effort as the patient progresses.

Figures 6 and 7 show a side view and a rear view of a third embodiment of a walker.

In this embodiment, the self-propelled chassis 1, la, 1b, lc comprises an upper rectangular frame, formed by two longitudinal members Id, Ig and two cross members le. The nacelle 10 is suspended from a carriage 19 which is equipped with rollers 20 which roll on the two longitudinal members ld, Ig.

A relative displacement sensor 21 is placed between the carriage and one of the cross members and it emits an electrical signal proportional to the relative longitudinal displacement of the carriage relative to its equilibrium position. The carriage is connected to the motor chassis by one or more springs 22 which tend to bring the carriage back to a stable equilibrium position.

The springs 22 are intended to force the patient to do an effort to move the carriage, so that it is possible to adjust this effort and increase the return force of the springs according to the progress made by the patient. The springs can be replaced by equivalent return devices, for example elastic buffers or by captive gas struts.

The chassis 1 comprises a single driving wheel 3 situated in the longitudinal axial plane which is driven by a motor 4 which is controlled by the signal delivered by the sensor 21 in the direction which cancels the relative movement of the carriage 19 relative to the chassis.

In this example, the self-propelled chassis moves under the combined action of the thrust transmitted to it by the springs 22 and the action of the wheel 3. The stiffer the springs 22, the more the effort due to the patient intervenes. in moving the self-propelled chassis.

The sensor 21 can be any known linear displacement sensor, for example, a capacitive sensor or an inductive sensor comprising a movable core displaceable inside a double inductor coil, or a resistive sensor comprising a resistance and a cursor linked to the carriage which moves along the resistor or an optical sensor comprising a light source which illuminates a photoelectric receiver with an intensity which varies with distance, etc.

The walkers according to the invention can easily be transformed into a passive self-propelled cart. The patient just has to lift their feet, grab the chassis with their hands and pull on their arms and the self-propelled chassis then advances in a continuous movement and transforms into a motorized wheelchair.

The nacelle 10 can be replaced by other equivalent forms of support, such as for example a seat, a harness, a saddle, etc. The word nacelle is used in a general sense to designate any of these supports .

The device according to FIG. 3 makes it possible to adjust the coefficient of proportionality between the relative movement of the platform support and the voltage delivered by the potentiometer. For this, it _is' t to move the position of the joint head 14a of the rod 14 into the slot 15a of the slider.

In all the embodiments, the coefficient of proportionality can also be varied electronically by modifying the gain of the amplifiers of the signals delivered by the sensors.

Claims (8)

1. Active walker device, intended for learning or rehabilitating the motor skills of a subject, of the type comprising a self-propelled chassis (1), mounted on wheels of which at least one (3) is driven by a motor ( 4) and a nacelle (10), in which said subject takes place, which has orifices (11) for the passage of the legs and which is supported by said chassis at a height such that the subject's feet touch the ground, characterized in that said nacelle is fixed on a mobile support (6) which is connected to said self-propelled chassis (1) by connecting means (7, 16) which allow it to move freely relative to said chassis in at least one direction, that said movable support (6) is connected to said chassis by at least one sensor (12, 17) which emits an electrical signal proportional to one of the components of the relative movement of said support (6) relative to said chassis (1) and that '' it includes servo loops, which connect each of said sensors to one of said motors (4) and which automatically control said motors to move said chassis with a movement which corresponds, in direction and intensity, to the relative movement of said support (6) relative to said chassis (1). 2. Active walker device according to claim 1, characterized in that said self-propelled chassis (1) has a generally rectangular shape and comprises four vertical angle uprights (la), that said mobile support (6) 'also has a general shape smaller rectangular whose sides are lower than those of said frame, that it is suspended from said uprights by four suspension members (7); that the lower end of at least one of these suspension members is connected to said chassis by a linear displacement sensor (12) which emits an electrical signal proportional to the component of the relative displacement of said lower end relative to said chassis which is parallel to the longitudinal axis of the chassis, that said chassis comprises as many motorized wheels (3) as sensors, which wheels are driven by a geared motor group (4) and that each motor (4) is connected to one sensors (12) by a servo loop which automatically controls said motor in the direction which cancels the signal emitted by said sensor. 3. Rollator device according to claim 2, characterized in that said movable support (6) is suspended from said uprights by four rods (7) which are articulated each around two horizontal axes (8, 9) transverse to said chassis. 4. Device according to claim 3, characterized in that said sensor is a rotary potentiometer (13) which is fixed to said chassis and the slider (15) of said potentiometer is connected to the lower end of one of the suspension links ( 7) by a link (14) parallel to the longitudinal axis of the chassis. 5. Device according to claim 2, characterized in that said mobile support (6) is suspended from said uprights by bending blades (16) located in transverse planes and at least one of these bending blades carries gauges of stress (17) which deliver an electrical signal proportional to the bending of the blade and to the longitudinal component of the relative movement of said movable support (6) relative to said chassis (1). 6. Device according to claim 5, characterized in that said movable support is suspended from the two front or rear uprights by lines such as wires (18d, 18g) or flexible, scalloped blades which allow relative movement in all directions, that it is suspended from the two other uprights by two bending blades (16d, 16g) situated in a transverse plane which both carry strain gauges (17d, 17g), that said self-propelled chassis comprises two motorized wheels (3d, 3g) located on the same axle and at the same end as the two bending blades and that the strain gauges located on each bending blade are connected by a motor servo loop (4d, 4g) which drives the motorized wheel located on the same side. 7. Device according to claim 1, characterized in that said self-propelled chassis (1) has a generally rectangular shape and comprises two upper beams (ld, lg), that the mobile support is a carriage (19) carried by rollers (20 ) which run on said beams, that said carriage is connected to said chassis by a sensor (21) of axial linear displacement, that said self-propelled chassis comprises a motorized wheel (3) situated in the longitudinal axial plane and that the motor (4) driving said wheel is connected to said sensor (21) by a servo loop. 8. Device according to claim 7, characterized in that said carriage (19) is connected to said chassis (1) by springs (22) whose force can be adjusted to measure the patient's effort as it progresses.

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