Field of the Invention

The present invention relates to a wearable lower extremity exoskeleton for regenerating lower body motion functionality of paraplegic patients without additional/external support.

Background of the Invention

Spinal cord paralysis is a condition, which results from the full or partial loss of sensorimotor and autonomous functionalities of the spinal cord. Various neurological diseases, car accidents, sports injuries, and falls are responsible for most of the cases in spinal cord functionality loss. In particular, the patients with diagnosis paraplegia experience functionality loss in their lower body even though their upper body is completely healthy. On the mobility side, being not able to walk is generally compensated with wheelchairs. However, there are health risks such that these patients may suffer from osteoporosis, calcification in the excretory system, spasticity, difficulties in digestion and excretion, and heterotopic ossification. Using a wheelchair also introduces some issues like pressure wound, bone and muscle tissue loss, and aches on arms and shoulders. Wheelchairs that the patients use have certain condition impediments when the steps, stairs, and narrow pathways exist. The most practical approach to regenerate the walking function of paraplegic patients is active exoskeletons. In this approach, patients wear a robotic system which is the exoskeleton that can move their legs in the forward direction. The exoskeletons in the state of the art are able to support the patient actively from hip and knee joint (2 DOF for each leg) for hip and knee flexion and extension (F/E) movements. Since 2 DOF isn’t enough for balancing and standing still, patients using these exoskeletons should actively use crutches to provide balance. When patients use crutches or walkers to balance with an exoskeleton, it causes aches on arms and shoulder joints after long periods. Thus, there is a need for a lower extremity exoskeleton providing balance without crutches.

Brief Description of the Drawings

An exemplary embodiment of the present invention is illustrated by way of example in the accompanying drawings to be more easily understood and uses thereof will be more readily apparent when considered in view of the detailed description, in which like reference numbers indicate the same or similar elements, and the following figures in which: Figure 1 is a view of exoskeleton in one exemplary embodiment of the present invention.

Figure 2 is a view of exoskeleton showing rotational orientation of articulations in one exemplary embodiment of the present invention.

Figure 3 is a schematic view of synergistic effect of hip articulation and foot articulation on range of sway motion in inverted pendulum mimicking manner in one exemplary embodiment of the present invention.

Figure 4 is a schematic view of foot plate with and without foot articulation during locomotion in one exemplary embodiment of the present invention.

Figure 5 is a schematic view of user joint-exo skeleton articulation coupling in one exemplary embodiment of the present invention.

Figure 6 is a sectional view of exoskeleton in one exemplary embodiment of the present invention.

Figure 7 is a view of drive bracket and transmitting rod of actuation transfer means in one exemplary embodiment of the present invention.

Figure 8 is a view of right leg in one exemplary embodiment of the present invention.

Figure 9 is a sectional view of exoskeleton comprising left leg in one exemplary embodiment of the present invention.

Figure 10 is an exploded view of exoskeleton in one exemplary embodiment of the present invention.

Figure 11 is an exploded sectional view of exoskeleton comprising right leg in one exemplary embodiment of the present invention.

Figure 12 is a view of resilient ankle means connected to a foot plate in one exemplary embodiment of the present invention. The elements illustrated in the figures are numbered as follows:

1. Exoskeleton

2. Back hip support

3. Side hip link

4. Thigh link

5. Shank link

6. Foot plate

7. Hip articulation

8. Thigh articulation

9. Shank articulation

10. Foot articulation

11. First actuator

12. Second actuator

13. Third actuator

14. Fourth actuator

15. First actuation transfer means

16. Second actuation transfer means

17. Third actuation transfer means

18. Fourth actuation transfer means

18.1 Crank

18.2 Coupler

18.3 Fever

18.4 Rocker

19. Driving shaft

20. Drive bracket

21. Transmitting rod

22. Resilient ankle means

23. Box

24. Base bracket

25. Resilient member

26. User connector

F. Feg

CoM. Center of Mass

HU. Human User Detailed Description

Embodiments of the present invention relates to a wearable lower extremity exoskeleton (1) comprising a back hip support (2) aligned with the hip level of a user in at least a standing position where the user worn the exoskeleton (1) and remained standing; at least two side hip links (3) each of which is rotatably connected to the one side of the back hip support (2) via at least one hip articulation (7) and two legs (L) each of which is rotatably connected to the each side hip link (3) via at least a thigh articulation (8).

Each leg (L) comprises a thigh link (4) to one end of which is rotatably connected to the side hip link (3), to other end of which is rotatably connected to a shank link (5) via at least one shank articulation (9) and a foot plate (6) rotatably connected to the shank link (5) via at least one foot articulation (10).

At least one first actuator (11) providing a rotational motion to the back hip support (2) and side hip links (3) in coronal plane via a first actuation transfer means (15) for supporting user in hip adduction and abduction; at least one second actuator (12) providing a rotational motion to the side hip links (3) and the thigh links (4) in sagittal plane via a second actuation transfer means (16) for supporting user in hip flexion and extension; at least third actuator (13) providing a rotational motion to the thigh links (4) and the shank links (5) in sagittal plane via a third actuation transfer means (17) for supporting user in knee flexion and extension; at least one fourth actuator (14) providing a rotational motion to the foot plates (6) in sagittal plane via a fourth actuation transfer means (18) for supporting user in ankle flexion and extension.

The first actuator (11), the second actuator (12), the third actuator (13) and the fourth actuator (14) are disposed around the hip level and back and/or front of the user in at least the standing position.

In embodiments of the present invention, since self-balancing locomotion dictates that the user body center of mass (CoM) must be laterally swayed in a small range, an inverted pendulum [representing CoM, figure 3] mimicking manner is adopted. For this reason, several improvements are provided to the present invention such that number of DOFs is increased (4 active DOF via actuators and articulations, and preferably 2 passive DOF via a resilient ankle means (22)). Firstly, hip adduction/abduction capability is also provided by adding a hip articulation (7). Thereby, sway motion of the user body CoM is mimicked and assisted. Secondly, in addition to hip and knee flexion/extension capability, ankle flexion/extension capability is also provided to exoskeleton (1) by adding a foot articulation (10) for each leg (L), see figure 2 and especially figure 4. Hip articulation (7) and foot articulation (10) synergically interact with each other providing sway motion within a small range. Figure 3 shows the range of the sway motion of the user body CoM with and without foot articulation (10). It is clear that foot articulations (10) provide significant contribution for limiting the sway motion range. Unlimited sway motion results in slow locomotion and balancing problems.

Other significant improvements provided in the present invention is disposing the first actuator (11), the second actuator (12), the third actuator (13) and the fourth actuator (14) around the hip level (a position at least above the shank articulation (9)) and back and/or front of the user in at least the standing position so as to accumulate mass and inertia of the exoskeleton (1) and to reduce the lateral weight of the exoskeleton (1). Although accumulation of the actuators comes with a burden of extra weight from the actuation transfer means, the accumulated mass and inertia significantly simplifies the dynamic system’s behavior of the exoskeleton (1) compared to exoskeletons with distributed mass. In conclusion, accumulation of mass and inertia, and reducing lateral weight increase the self-balancing capability, locomotion speed and accuracy of the exo skeleton (1).

In one embodiment of the present invention, at least one of the actuator is disposed around the hip level where above the shank articulation (9) due to space constraint.

In one embodiment of the present invention, the foot plate (6) is rotatably connected to the shank link (5) via at least one foot articulation (10) though a resilient ankle means (22) which provide a back-and-forth motion to the foot plate (6) in longitudinal axis. The resilient ankle means (22) keep the foot plate (6) in contact with the foot of the user in a selected tension which contributes the self-balancing. In one alternative of this embodiment, the resilient ankle means (22) comprises a box (23), a base bracket (24) disposed below the box (23), slidable inside the box (23) and resilient member (25) preferably a helical/coil spring.

In one embodiment of the present invention, the actuators are rotary motors. In this embodiment, at least one actuation transfer means (11, 12, 13, 14) comprises a drive bracket (20) fixed to a driving shaft (19) of the actuator, a transmitting rod (21) one end of which rotatably connected to the drive bracket (20) and other end of which rotatably connected to the back hip support (2) or corresponding link (3, 4, 5), or the foot plate (6) for transmitting rotational actuation of the actuators (11, 12, 13, 14).

Due to relatively high distance between the fourth actuator (14) and the foot plate (6), the fourth actuation transfer means (18) may be different than the other actuation transfer means. In one embodiment of the present invention, the fourth actuators (14) are a rotary motor and the fourth actuation transfer means (18) comprise a crank (18.1) fixed to a driving shaft (19) of the actuator. The fourth actuation transfer means (18) also comprise a coupler (18.2) one end of which rotatably connected to the crank (18.1) and other end of which rotatably connected to one end of a lever (18.3). The lever (18.3) is rotatably connected to thigh link (4) or shank articulation (9) from a middle point of itself so as to act as a fulcrum. The fourth actuation transfer means (18) also comprises a rocker (18.4) one end of which rotatably connected to other one end of the lever (18.3) and other end of the rocker (18.4) connected to the foot plate (6).

In one embodiment of the present invention, wearable lower extremity exoskeleton (1) comprises a receiver adapted to receive actuation commands for actuators. Thus, actuators of the exoskeleton (1) can be controlled/commanded remotely for desired locomotion.

In one embodiment of the present invention, wearable lower extremity exoskeleton (1) comprises a control unit adapted to control/command actuation of the actuators for desired locomotion.

Desired locomotion may be fast/slow gait, sitting down, stairs ascent/descent or step in variable length.

In one embodiment of the present invention, wearable lower extremity exoskeleton (1) comprises a control unit adapted to control/command actuation of the actuators for balancing the exoskeleton (1) according to at least one orientation sensor and/or proximity sensor and/or displacement sensor and/or position sensor. Thanks to the accumulated mass and inertia significantly which simplifies the dynamic behavior of the exoskeleton (1), balancing the exoskeleton (1) is much easier. Thus, required number of sensors is significantly reduced.

In one embodiment of the present invention, back hip support (2) and/or side hip links (3) and/or thigh link (4) and/or shank link (5) and/or first actuation transfer means (15) and/or second actuation transfer means (16) and/or third actuation transfer means (17) and/or fourth actuation transfer means (18) are length adjustable so that exoskeleton (1) is configurable to any user by aligning the articulations to joints of the user and/or by adjusting back hip support (2) width and side hip links (3) depth.

In one embodiment of the present invention, wearable lower extremity exoskeleton (1) comprises at least one user connector (26) such as a hook-and-loop fastener for attaching the user to the exoskeleton (1). The user connector (26) may be provided for attached to user thigh and/or shank and/or foot. The user connector (26) position may be adjustable in three axis.

In one embodiment of the present invention, supports and/or links and/or foot plate (6) and/or articulations and/or actuation transfer means are made of carbon fiber composite which significantly reduce the overall weight of the exoskeleton (1).