User mobility assistance device

Abstract

The invention relates to a device for assisting the movement of a user (70) on a surface comprising: - a chassis (18) having a sagittal plane and a frontal plane (14), the chassis comprising at least one support integral with the chassis and intended to be in contact with the surface at a point on the sagittal plane distant from the frontal plane (14), - two suspension arms (26, 28) extending mainly in the frontal plane (14), each being connected to the chassis, - two drive wheels (34, 36) intended to roll on the surface, each drive wheel comprising a hub fixed to each suspension arm, - two shock absorbers (42, 44) connected to the chassis and to a suspension arm, - a platform (20) connected to the chassis receiving the user, - a module for controlling the drive wheels according to an inclination of the chassis in the frontal plane relative to the surface. Figure for the abstract: Fig. 4.

Description

Title of the invention: Device to assist a user's movement

[0001] The invention relates to a device to assist the movement of a user, and more particularly a person with reduced mobility. The device can be used by an able-bodied person. It can also be used to move an inert load. The device can be used like a wheelchair in which the user sits.

[0002] Most wheelchairs have four wheels to ensure the user's stability. These wheelchairs are bulky. They occupy a significant amount of floor space, which can reduce their maneuverability, particularly in confined spaces. Their bulk often results in a significant weight. Four-wheeled wheelchairs can be motorized. The electric motor and associated batteries must be adapted to the user's weight and the weight of the wheelchair itself. The heavier the wheelchair, the heavier the equipment required for its motorization.

[0003] In order to reduce the mass and size of the wheelchairs, tests were carried out with two-wheeled wheelchairs such as, for example, described in patent application WO 2018 / 096175 AL. To ensure the stability of the wheelchair, an inverted pendulum platform of the two-wheeled gyropod type is used. The presence of the two wheels ensures lateral stability of the wheelchair, preventing the user from experiencing a sensation of lateral imbalance.

[0004] Furthermore, there are mobility aids based on a self-balancing unicycle, often called a gyrowheel or electric unicycle. The gyrowheel consists of a single, enclosed, motorized wheel. The user stands on footrests attached to the enclosed wheel and positioned on either side of the wheel. The wheel's motor is controlled by the user shifting their weight forward or backward. Gyroscopic sensors detect these imbalances and control the motor accordingly. Turns can be made by dissociating upper and lower body movements. The user orients their shoulders in the desired direction and adjusts the pressure of their feet and lower legs on the enclosed wheel and footrests to execute a turn. Some highly experienced users can even perform a spin on the spot, often called a "top turn."The self-balancing unicycles currently available on the market are lightweight, compact, and allow for maneuvering in tight spaces. These unicycles allow the user to experience imbalance, both sagittally and frontally. However, riding a self-balancing unicycle is reserved for [specific group / individuals - context needed]. Able-bodied users only. It is completely out of the question for paraplegic users to use it. It also seems difficult to offer such equipment to elderly people or those undergoing functional rehabilitation due to the risk of falls.

[0005] The invention aims to provide a device to assist a user's movement, ensuring excellent stability similar to that of a four-wheeled wheelchair, while allowing the user to experience lateral instability as on a self-balancing unicycle. Thanks to its stability, the invention can accommodate a user with reduced mobility.

[0006] To this end, the invention relates to a device to assist a user in moving across a surface, the device comprising: - a frame having a sagittal plane and a frontal plane perpendicular to the sagittal plane, the frame comprising at least one support integral with the frame and intended to be in contact with the surface at a point on the sagittal plane distant from the frontal plane, - two suspension arms extending mainly in the frontal plane, each between two ends, each suspension arm being connected to the chassis at one of its ends by a pivot joint with an axis parallel to the sagittal plane, - two drive wheels designed to roll on the surface, each drive wheel comprising a hub fixed to one end of one of the two suspension arms, - two shock absorbers, each extending between two ends, each shock absorber being connected to the chassis at one of its ends by a first joint at a distance from the pivot joint and to one of the suspension arms at a distance from the first end of the suspension arm in question by a second joint, - a platform configured to receive the user, the platform being connected to the chassis, - a control module for the two drive wheels based on the inclination of the chassis in the frontal plane relative to the surface.

[0007] Advantageously, the platform is connected to the chassis by means of a sliding link having a degree of freedom in translation perpendicular to the sagittal plane.

[0008] Advantageously, the device further includes a disengageable brake allowing the platform to be locked in the middle position along the sliding link.

[0009] Advantageously, the platform is connected to the chassis by means of one or more elastic elements tending to return the platform to a median position relative to the sagittal plane in its movement along the sliding joint.

[0010] Advantageously, the sliding link is motorized.

[0011] Advantageously, the control module is configured to allow the motor to be locked in the mid-position of the platform during its movement along the sliding joint.

[0012] Advantageously, the chassis comprises two supports attached to the chassis and intended to be in contact with the surface at points in the sagittal plane arranged at a distance and on either side of the frontal plane.

[0013] Advantageously, the two supports are each formed by a swiveling wheel.

[0014] Advantageously, the chassis and the two suspension arms are configured so that when the chassis tilts, the drive wheels tilt in such a way that a point of contact of each drive wheel with the surface is moved towards the inside of a curve followed by the movement of the device.

[0015] The invention will be better understood and other advantages will become apparent upon reading the detailed description of an embodiment given by way of example, a description illustrated by the accompanying drawing in which:

[0016] Figures 1 and 2 represent two kinematic diagrams of a movement aid device according to the invention, each in a different position of the device;

[0017] [Fig.3] represents a front view example of a device according to the invention;

[0018] [Fig.4] represents the device of [Fig.1] on which a user has taken a seat;

[0019] [Fig.5] represents in perspective the device of [Fig.1];

[0020] [Fig.6] represents a variant of the device of [Fig.1] equipped with a slide;

[0021] Figure 7 shows in more detail a motorized slide that can be fitted to the vehicle of the [Fig.6].

[0022] For the sake of clarity, the same elements will bear the same references in the different figures.

[0023] A movement aid device 10 according to the invention is configured to move on a surface 12 considered to be flat. In the various figures, the surface 12 is shown to be horizontal. The surface 12 is, for example, the ground. In practice, it is also possible to operate the device 10 on a sloping or slightly uneven surface.

[0024] Figures 1 and 2 represent the device 10 in kinematic diagram form. The device 10 is designed to move in a straight line or along a curve. Figures 1 and 2 are shown in a frontal plane 14 of the device 10. The frontal plane 14 is perpendicular to the surface 12 whether the device 10 moves in a straight line or along a curve. In other words, when the surface 12 is horizontal, the frontal plane 14 remains vertical. A sagittal plane 16 of the device 10 is also defined. The sagittal plane 16 is perpendicular to the frontal plane 14. When the device 10 moves in a straight line, it moves in the sagittal plane 16. When the device 10 moves along a curve, the curve followed by the device's movement is tangent to the sagittal plane 16. In Figures 1 and 2, the sagittal plane 16 is shown upright.

[0025] The device comprises a chassis 18 and a platform 20 connected to the chassis 16. The The platform is configured to receive the user. We will see later several ways to connect the platform 20 to the chassis 18.

[0026] The frame 18 includes at least one support integral with the frame 18 and intended to be in contact with the surface 12 at a point on the sagittal plane 16 distant from the frontal plane 14. One support may suffice to ensure the stability of the device 10. However, it is advantageous to provide two supports, labeled 22 and 24 in the various figures. The two supports 22 and 24 are both positioned at a distance from the frontal plane 14 and on either side of it. In Figures 1 and 2, shown in the frontal plane 14, the two supports 22 and 24 are one behind the other and appear to coincide. The two supports 22 and 24 slide on the surface 12 when the device 10 moves.

[0027] The device 10 comprises two suspension arms 26 and 28 extending mainly in the front plane 14 each between two ends, 26a and 26b for the suspension arm 26 and between two ends 28a and 28b for the suspension arm 28. The suspension arm 26 is connected at its end 26a to the chassis 18 by a pivot joint 30 with axis parallel to the sagittal plane 16 and the suspension arm 28 is connected at its end 28a to the chassis 18 by a pivot joint 32 with axis parallel to the sagittal plane 16.

[0028] The device 10 comprises two drive wheels 34 and 36 designed to roll on the surface 12 to propel the device 10. The drive wheel 34 comprises a hub 38 fixed to the end 26b of the suspension arm 26, and the drive wheel 36 comprises a hub 40 fixed to the end 28b of the suspension arm 28. The drive system for the wheels 34 and 36 is not shown. The drive wheels 34 and 36 are advantageously wheel motors that can each be driven independently of the other. Alternatively, the drive system for each drive wheel 34 and 36 can be located away from the corresponding wheel and, for example, mounted on the chassis 18.

[0029] The device 10 comprises two shock absorbers 42 and 44, each extending between two ends, 42a and 42b for shock absorber 42 and between two ends 44a and 44b for shock absorber 44. Shock absorber 42 is connected at its end 42a to the chassis 18 by a joint 46 disposed on the chassis 18 at a distance from the pivot joint 30, and shock absorber 44 is connected at its end 44a to the chassis 18 by a joint 48 disposed on the chassis 18 at a distance from the pivot joint 32. Shock absorber 42 is connected at its end 42b to the suspension arm 26 at a distance from its end 26a by a joint 50. Similarly, shock absorber 44 is connected at its end 44b to the suspension arm 28 at a distance from its end 28a by a joint 52.

[0030] The joints 46, 48, 50, and 52 can be pivot joints with axes parallel to the sagittal plane 16, as with the pivot joints 30 and 32. To avoid indeterminacy of the assembly between the chassis 18, the suspension arms 26 and 28, and the shock absorbers 42 and 44—indeterminacy due to the necessary parallelism of the axes of the pivot joints—it is advantageous to connect the shock absorbers to the chassis 18 and the respective suspension arms. by ball joints as shown in figures 1 and 2. It is also possible to implement short pivot joints with functional play in the orientation of the respective axes.

[0031] Thus, for the wheel 34, the joints 30, 46 and 50 form a deformable triangle, in the front plane 14, according to the forces absorbed by the shock absorber 42. Similarly, for the wheel 36, the joints 32, 48 and 52 form a deformable triangle, in the front plane 14, according to the forces absorbed by the shock absorber 44.

[0032] Figure 1 shows the device 10 moving in a straight line, and Figure 2 shows it moving in a curve. In other words, in Figure 1, assuming the chassis 18 and the suspension arms 26, 28 are symmetrical with respect to the sagittal plane 16, the two deformable triangles are also symmetrical with respect to the sagittal plane 16. The two shock absorbers 42 and 44 are both subjected to the same modulus of force. In Figure 2, the sagittal plane 16, linked to the chassis 18, is inclined towards the inside of the curve. The shock absorber 42 contracts, and the shock absorber 44 extends. The chassis 18 pivots about a straight line passing through the supports 22 and 24, which remain in contact with the surface 12.

[0033] The two shock absorbers 42 and 44 each have, for example, an elastic element that can stretch or stretch depending on the lateral displacement of the user's weight relative to the frame 18. The shock absorbers 42 and 44 are configured to allow an inclination of the sagittal plane 16 relative to a median position, as shown in [Fig. 1], of up to 50° and preferably up to 40° on either side of the median position. Stops can limit the movement of the suspension arms 26 and 28 relative to the frame 18 to prevent the inclination of the sagittal plane 16 from exceeding a given value, for example, 50° or 40°. The elastic element may be accompanied by a separate shock absorber to filter out any oscillations caused by the user's weight displacement.

[0034] The two drive wheels 34 and 36 are controlled to follow the trajectory of the device according to the inclination of the sagittal plane 16 with respect to the surface 12. It is possible to define the inclination of the sagittal plane 16 with respect to a plane formed by the supports 22, 24 and the contact points of the wheels 34 and 36 on the surface 12. In [Fig. 1], the sagittal plane 16 is perpendicular to the surface 12 and in [Fig. 2], the sagittal plane 16 is inclined at an angle α other than 90° with respect to the surface 12.

[0035] The device 10 includes a control module 60 for the two drive wheels 34 and 36, depending on the inclination α of the chassis 18 in the frontal plane relative to the surface 12. In Figures 1 and 2, the control module 60 is shown attached to the chassis 18. The control module can be positioned at any other location on the device, even at a distance from the kinematic assembly described above. Wired or wireless interfaces can be used to connect the control module to the drive wheels 34 and 36.

[0036] In the position shown in [Fig. 1], the two drive wheels 34 and 36 are driven at the same speed in the same direction of rotation. In [Fig. 2], wheel 34 is slowed down relative to wheel 36. Wheel 34 is on the inside of the curve. The user, seated on the platform 20, leans towards the inside of the curve. For a large angle α, it is possible to stop the rotation of wheel 34, allowing the device 10 to pivot on the surface 12 around the point of contact of wheel 34 with the surface. It is even possible, as the angle α deviates from 90°, to reverse the direction of rotation of wheel 34 so as to reduce the radius of curvature of the curve formed by the movement of the device. The instantaneous center of rotation of the device 10 can then be located between the two drive wheels 34 and 36, or even at an equal distance from the two wheels, thus forming a figure called a spinning top where the device 10 rotates on itself.

[0037] Generally, outside of the device 10, a user, to initiate a movement, leans forward to create an imbalance in their body, which they then compensate for with the movement they wish to initiate. Starting from a straight line, to initiate a curve to the right or left, the user leans towards the inside of the desired turn. This imbalance is particularly noticeable on a two-wheeled vehicle. The invention allows a user seated on the platform 20 to experience an imbalance similar to that which they would experience on a two-wheeled vehicle whose wheels are in contact with the ground at the two support points 22 and 24. The sensation of imbalance is obtained by tilting the chassis 18. This sensation of imbalance, in combination with a movement of the device 10, is particularly useful for a user with a disability undergoing rehabilitation.This combination is also very useful for specific uses of device 10, for example for performing choreography.

[0038] In the position shown in [Fig. 1] where the sagittal plane 16 is perpendicular to the surface 12, the pivot joints 30 and 32 are equidistant from the surface 12 and the axes of rotation of the drive wheels are, for example, parallel to the surface 12. To improve the stability of the device 10, it is possible to move the contact points of the drive wheels 34 and 36 on the surface 12 further away from the sagittal plane 16 by slightly modifying the orientation of the axes of the drive wheels with respect to a direction parallel to the surface 12.

[0039] In the position of [Fig. 2], where the sagittal plane 16 is inclined relative to its median position shown in [Fig. 1], the pivot joint 30 moves closer to the surface 12 and the pivot joint 32 moves away from it, causing the drive wheels 34 and 36 to pivot around a sagittal axis. This pivoting of the wheels tends to move the point of contact of the wheels on the surface 12 towards the inside of the curve formed by the movement of the device 10. This helps to limit the risk of destabilization of the device due to a The user's imbalance is directed towards the inside of the curve. The purpose of this displacement of the drive wheel contact point is to prevent the vertical projection of the center of gravity of the device and the user seated on the platform 20 from lying outside a segment connecting the two drive wheel contact points on the surface 12 in the frontal plane 14. The displacement of the drive wheel contact point is achieved by tilting the drive wheels as shown in [Fig. 2]. This tilt is achieved by the geometric configuration of the chassis 18 and the suspension arms 26 and 28.

[0040] Figure 3 shows, in the front plane 14, an example of a device 10. The frame 18 is formed primarily from a set of shaped tubes assembled, for example, by welding. Any other shape and means of producing the frame 18 is, of course, possible. More generally, the frame 18 forms a single-piece mechanical component with no internal degrees of freedom. Figure 3 shows the suspension arms 26 and 28, the drive wheels 34 and 36, and the shock absorbers 42 and 44. The platform 20, in the example shown, comprises a seat 62, a backrest 64, and two armrests 66, allowing the user to sit on the seat 62 and be supported by the backrest 64 and the armrests 66. It is, of course, possible to design a simpler platform, for example, with only the seat 62, or a more complex one, including a footrest, a headrest, etc.Since device 10 is particularly suitable for users with reduced mobility, platform 20 can be adapted to the user's disability so that they can safely take their place on platform 20 and withstand lateral imbalance.

[0041] The supports 22 and 24 can be low-friction pads capable of sliding on the surface 12. To facilitate sliding, as shown in [Fig. 3], the supports 22 and 24 can be non-motorized swivel casters. Each caster can rotate freely about an axis perpendicular to the sagittal plane 16, and this axis of rotation is itself pivotally mounted about an axis contained in the sagittal plane 16. During straight-line movement, as shown in Figures 1 and 3, the axis of each caster is horizontal and the pivot axis is vertical. The swivel casters 22 and 24 provide support that can slide freely on the surface 12 along two translational degrees of freedom carried by the plane of the surface 12.

[0042] Figure 4 shows, still in the frontal plane 14, the device 10 on the platform 20 of which a user 70 has taken their place. The user 70 leans to their left, causing the shock absorber 42 to compress and the shock absorber 44 to extend.

[0043] Figure 5 shows device 10 in perspective. This figure illustrates the relative position of the two swivel casters 22 and 24 on either side of the front plane containing the axes of the two drive wheels 34 and 36.

[0044] The platform 20 can be attached to the frame 18. To initiate a turn, the user 70 leans either to the right or to the left as illustrated in [Fig. 4]. The platform attached to the frame 18 is well suited to a user 70 who can move their upper body. The user 70 will be able to lean to the right or to the left. If the user 70 has difficulty moving their upper body, the device can be equipped with a sliding link 80. More specifically, as shown in [Fig.6], the platform 20 is connected to the frame 18 by means of the sliding link 80, the axis of translation of which 82 is perpendicular to the sagittal plane 16. Thanks to the sliding link 80, the user 70 can move their entire body, and not just their upper body, laterally on either side of the sagittal plane 16 and thus shift their weight to compress either the shock absorber 42 or the shock absorber 44.

[0045] In addition to the sliding joint 80, it is possible to connect the platform 20 to the frame 18 by means of one or more elastic elements 84 tending to return the platform 20 to a median position with respect to the sagittal plane 16. The elastic element(s) 84 may be accompanied by a damper to filter any unwanted oscillations of the platform 20's translational movements along the sliding joint 80. The stiffness of the elastic element(s) 84 can be adjusted according to the motor skills of the user 70.

[0046] Alternatively or in addition to the elastic elements 84, it is possible to motorize the sliding link 80. Such motorization is particularly useful for a user 70 who cannot move their upper body in order to shift their weight laterally.

[0047] The movement of the platform 20 along the sliding link 80 may cause apprehension on the part of a user when using the device 10. This apprehension may be temporary, and it is advantageous to provide a disengageable brake allowing the platform to be locked in the middle position along the sliding link 80. This brake can be implemented for a sliding link 80 equipped or not with a motor.

[0048] Figure 7 shows an example of motorization of the sliding joint 80. In the example shown, the sliding joint 80 is formed by rails 86 fixed to the frame 18 and slides 88 that can move along the rails 86. The rails 86 extend perpendicularly to the sagittal plane 16 to form the axis 82 of the sliding joint 80. The platform 20, not shown in Figure 7, is fixed to the slides 88. It is understood that the sliding joint 80 can be made in any other way. For example, the rails can be fixed to the platform and the slides to the frame.

[0049] The motorization is here achieved by means of a worm screw 90 extending perpendicularly to the sagittal plane 16 and having one degree of freedom in rotation with respect to to the frame 18 along an axis 92 perpendicular to the sagittal plane 16. A nut 94, cooperating with the worm gear 90, is fixed to the platform 20. The worm gear 90 is driven in rotation by a motor 96 fixed to the frame 18. By rotating the worm gear 90, the nut 94 drives the platform 20 in translation along the axis 82. The slides 88 provide redundancy in the guidance of the sliding joint 80. Other embodiments of the motorization of the sliding joint 80 are, of course, possible. In particular, it is conceivable to have a nut fixed to the frame and a worm gear having one degree of freedom in rotation relative to the platform. The motor driving the rotation of the worm gear is then advantageously fixed to the platform 20.As an alternative to implementing a helical link (worm gear 9 and nut 94) between the platform 20 and the chassis 18, it is possible to implement a linear actuator allowing the movement of the platform 20 relative to the chassis 18 perpendicular to the sagittal plane 16.

[0050] It is possible to couple the motorization of the movement of the platform 20 to the presence of elastic elements 84 to take into account particular motor difficulties of certain users.

[0051] The motorization of the sliding link 80 can be controlled by the control module 60. A human-machine interface, such as a mini joystick available to the user, allows them to move the platform 20 by activating the motorization of the sliding link 80. Other types of human-machine interfaces, such as a voice interface, are also possible. The human-machine interface can be connected, wired or wirelessly, to the control module 60 or to any other module that allows the movement of the platform 20 along the sliding link 80 to be controlled.

[0052] The human-machine interface can also control the forward or reverse movement of the device 10 independently or coupled with the speed variations between the drive wheels 34 and 36 allowing the device 10 to turn.

Claims

Claims

1. Device for assisting the movement of a user (70) on a surface (12), the device (10) comprising: - a chassis (18) having a sagittal plane (16) and a frontal plane (14) perpendicular to the sagittal plane (16), the chassis (18) comprising at least one support (22, 24) integral with the chassis (18) and intended to be in contact with the surface (12) at a point of the sagittal plane (16) distant from the frontal plane (14), - two suspension arms (26, 28) extending mainly in the frontal plane (14) each between two ends (26a, 26b, 28a, 28b) each suspension arm (26, 28) being connected to the chassis (18) at a first of its ends (26a, 28a) by a pivot connection (30, 32) with an axis parallel to the plane sagittal (16), - two driving wheels (34, 36) intended to roll on the surface (12), each of the driving wheels (34, 36) comprising a hub (38, 40) each fixed to a second of the ends (26b, 28b) of one of the two suspension arms (26, 28),- two shock absorbers (42, 44) each extending between two ends (42a, 42b, 44a, 44b), each shock absorber (42, 44) being connected to the chassis (18) at a first of its ends (42a, 44a) by a first articulation (46, 48) at a distance from the pivot connection (30, 32) and to one of the suspension arms (26, 28) at a distance from the first end (26a, 28a) of the suspension arm in question (26, 28) by a second articulation (50, 52), - a platform (20) configured to receive the user (70), the platform (20) being connected to the chassis (18), - a control module (60) of the two drive wheels (34, 36) as a function of an inclination (a) of the chassis (18) in the frontal plane (14) relative to the surface (12).,

2. Device according to claim 1, in which the platform (20) is connected to the frame (18) by means of a sliding connection (80) having a degree of freedom in translation (82) perpendicular to the sagittal plane (16).

3. Device according to claim 2, further comprising a disengageable brake making it possible to lock the position of the platform (20) in the middle position along the sliding connection (80).

4. Device according to one of claims 2 or 3, in which the platform (20) is connected to the chassis (18) by means of one or more

5.

6.

7.

8. elastic members (84) tending to return the platform (20) to the median position relative to the sagittal plane (16) in its movement along the sliding connection (80). Device according to one of claims 2 to 4, in which the sliding connection (82) is motorized. Device according to one of the preceding claims, in which the frame (18) comprises two supports (22, 24) integral with the frame (18) and intended to be in contact with the surface (12) at points of the sagittal plane (16) arranged at a distance and on either side of the frontal plane (14). Device according to claim 6, in which the two supports are each formed from a pivoting caster (22, 24). Device according to one of the preceding claims in which the chassis (18) and the two suspension arms (26, 28) are configured so that during an inclination (a) of the chassis (18), the driving wheels (34, 36) tilt so that a point of contact of each driving wheel (34, 36) with the surface is moved towards the inside of a curve followed by the movement of the device (10).

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