WO2019223568A1

WO2019223568A1 - Soft robotic glove for rehabilitation

Info

Publication number: WO2019223568A1
Application number: PCT/CN2019/086725
Authority: WO
Inventors: Yong Hu; Rongwei WEN; Zheng Wang
Original assignee: The University Of Hong Kong
Priority date: 2018-05-23
Filing date: 2019-05-14
Publication date: 2019-11-28
Also published as: CN112040922B; CN112040922A

Abstract

A device related to a soft robotic glove (15) is provided. A device can comprise a soft actuator (14) with a pair of fittings (4, 5), a pair of long polymer tubes (6, 7), one mounted in one end of each fitting (4, 5), a short polymer tube (1) mounted on the other end of each fitting (4, 5) and connecting the pair of fittings (4, 5), a pair of polymer plugs (2, 3) mounted on each end of short polymer tube (1) so as to isolate the air in the short polymer tube (1), a pair of polymer pistons (8,9) mounted in each of long polymer tube (6, 7), polymer rod (13), and a wire rope (10) passing through all of the tubes (1, 6, 7). The distance between two polymer pistons (8, 9) can be approximately equal to the length of wire rope (10).

Description

SOFT ROBOTIC GLOVE FOR REHABILITATION

FIELD OF INVENTION

Embodiments of the subject invention generally relate to improvements in a robotic glove and more particularly to a robotic glove with soft actuators.

BACKGROUND OF THE INVENTION

The traditional design of a robotic glove does not provide sufficient grip strength for patients. This can be due to the positioning of the mechanisms of the robotic glove in relation to a patient’s hand.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the subject invention provide a soft robotic glove whose fingers can be manipulated to extend and bend through the use of soft actuators. Each soft actuator can be lightweight and have a simple structure.

An embodiment of the subject invention provides a soft robotic glove comprising a soft actuator with a pair of fittings, a pair of long polymer tubes mounted to one end of each fitting, a short polymer tube mounted on the other end of each respective fitting and connecting the pair of fittings, a pair of polymer plugs mounted on each end of the short polymer tube so as to isolate the air flow between the pair of long polymer tubes, a pair of polymer pistons respectively mounted in each long polymer tube, a polymer rod, and a wire rope passing through the short polymer tube and the pair of long polymer tubes. The distance between two polymer pistons can be approximately equal to the length of the wire rope.

As compressed air flows into an outer long polymer tube, an outer polymer piston in the outer long polymer tube is forced outward by the compressed air. The polymer rod is connected to the outer polymer piston by the wire rope and is forced outward by the outer polymer piston.

Furthermore, as compressed air flows into an inner polymer tube, the inner polymer piston is forced in an opposite direction of the polymer rod. The polymer rod is connected to the inner polymer piston by the wire rope and is pulled back into the outer long polymer tube.

In an embodiment of the subject invention, a soft robotic glove can comprise a soft actuator mounted on a back side of a glove. A polymer rod can have one end inserted into the soft actuator and the other end extended towards a fingertip of the glove. A fabric can be sewn on the back side of a finger of the glove by a constrained line. The fabric can be made from a flexible material that permits the rod to slide in and out of the soft actuator. A wire rope can be connected to one end of the rod and a piston on the other end of the wire rope. A pair of wire rope sleeves can be mounted on each end of the wire rope. Compressed air can be directed into the soft actuator to push pistons situated in opposite directions and cause the rod to either extend or retract from the soft actuator.

As the rod extends outwards from the soft actuator, the rod extends forward and bends within the flexible fabric guiding the finger to bend. When the patient’s finger is bent, the constrained line can automatically adjust the flexible fabric to have a minimum curvature that effectively transmits the force from the soft actuator to the fingertip of the glove. Furthermore, as the polymer rod retracts back into the soft actuator, the fingertip is forced upward and the patient’s finger is forced to extend.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a diagram of a partial cross-sectional view of the soft actuator.

Figure 2 is a diagram of a side view of a bent index finger fitted with the soft robotic glove.

Figure 3 is a diagram of a side view of an extended index finger fitted with the soft robotic glove.

DETAILED DISCLOSURE OF THE INVENTION

A soft actuator of the robotic glove can be seen in Figure 1. A short polymer tube 1 is provided with polymer plugs 2, 3 at each respective end of the short polymer tube 1. The diameter of the polymer plugs 2, 3 can be substantially equal to the outer diameter of the short polymer tube 1. Each end of the short polymer tube 1 is fitted inside a respective port of an outer fitting 4 and an inner fitting 5. An outer long polymer tube 6 and an inner long polymer tube 7 can be fitted inside a respective opposite port of each of the fittings 4, 5. An outer polymer piston 8 and inner polymer piston 9 can be fitted inside each long polymer tube 6, 7, respectively. A diameter of a polymer piston 8, 9 can be substantially equal to the inside diameter of the respective long polymer tube 6, 7. A wire rope 10 can be fitted inside the short and long polymer tubes 1, 6, and 7 and pass through the plugs 2, 3 and the pistons 8, 9 with one end connected to the rod 13. Wire rope sleeves 11, 12 can be mounted on each respective end of the wire rope 10 and outside each of the polymer pistons 8, 9. The rod 13 can be fitted inside the outer long polymer tube 6 at an opposite end of the wire rope sleeve 11 from the piston 8 and extend out from the long polymer tube 6 from an end opposite to the outer fitting 4.

A glove 15 can be provided with a soft actuator 14 mounted at wrist end of the glove 15, as seen in Figures 2 and 3. An outer end of the rod 13 can be mounted on a fingertip of the glove 15. A portion of the rod 13 extending out of the soft actuator 14 can be covered by fabric 16, which can be sewn loosely on the glove 15 by a constrained line 17. Each end of the constrained line 17 can be affixed onto the glove 15.

In order to extend the rod 13, compressed air can be injected into a top port of the outer fitting 4. The top port of the inner fitting 5 can remain open to the ambient atmosphere or low pressure compressed air. The plugs 2, 3 can obstruct the injected compressed air from entering the short polymer tube 1. The injected compressed air can push the outer piston 8 and the wire rope sleeve 11 outward from the long polymer tube 6 and extend the rod 13 outward from the soft actuator 14.

In order to retract the rod 13, compressed air can be injected through a top port of the inner fitting 5. The top port of inner fitting 4 can remain open to the ambient atmosphere or low pressure compressed air. The plugs 2, 3 can obstruct the injected compressed air from entering the short polymer tube 1. The injected compressed air can push the inner piston 9 and the inner wire rope sleeve 12 outward from the inner long polymer tube 7. Thus the wire rope 10 pulls the rod 13 back towards the soft actuator and the rod 13 can retract into the outer long polymer tube 6.

In order to bend a finger, the rod 13 can be extended towards a fingertip by the soft actuator 14, as shown in Figure 2. Due to the compliance of the rod 13, the rod 13 can bend in the fabric 16 and the finger can bend as the fingertip is being forced downward. When the finger is in a bent position, the length of constrained line between fabric 16 and glove 15 can auto adjust in order to allow the fabric 16 to have a smooth curvature. Therefore, the portion of the rod 13 inside the fabric 16 has a minimum curvature variation along the full length of the rod 13, so that the force is transmitted from soft actuator 14 to fingertip with minimal loss.

In order to retract a finger, the rod 13 can be retracted back into the soft actuator 14 as described above. The finger inside the soft robotic glove 15 can extend as the fingertip is forced upwards, as shown in Figure 3.

As the height of the fingertip end of the fabric 16 differs, the direction of force on the fingertip differs. Therefore, the robotic glove can generate different trajectories as desired by a patient using the soft robotic glove. When the soft actuator is fitted on a glove, the rod 13 does not need to be mounted relative to the joint of the finger. The soft robotic glove can adapt to different finger lengths of the patients.

The force generated by the soft actuator is transmitted to the fingertip by the rod 13 with minimum curvature variation when the finger is bent. Therefore, the robotic glove can generate a satisfactory bending force while being lightweight. Furthermore, as the rod 13 is positioned close to and along the finger, the force can be applied evenly across the finger.

Because the material of each part of soft actuator is lightweight, the total weight of the soft actuator is light compared to a conventional actuator that is made of metal. Thus the soft actuator can be mounted on a glove with little burden to a patient. Furthermore, even being comparatively lightweight, the glove soft actuator mounted glove can provide a large force and a wide bending angle for finger flexion and extension exercises for the patient.

All patents, patent applications, provisional applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.

It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application. For example, the materials recited herein for each exemplified part, such as “polymer” and “wire rope” , can be substituted by other materials suitable for their intended purpose as would be readily recognized by one of ordinary skill in the art. In addition, any elements or limitations of any invention or embodiment thereof disclosed herein can be combined with any and/or all other elements or limitations (individually or in any combination) or any other invention or embodiment thereof disclosed herein, and all such combinations are contemplated with the scope of the invention without limitation thereto.

Claims

A soft robotic glove comprising:

at least one actuator configured to be attached to a glove;

at least one flexible rod configured to be extended and retracted by the at least one actuator; and

a flexible fabric covering a portion of the at least one flexible rod and sewn on a finger of the glove by a constrained line;

wherein an expanded length of the flexible fabric is longer than a length of the rod.
The soft robotic glove of claim 1, wherein a cross section of the flexible rod is either round, elliptical, or rectangular, wherein, the flexible rod is a polymer rob, and can bend due to its compliance when the flexible rod is extended toward a fingertip by the actuator.
The soft robotic glove of claim 1, wherein the at least one actuator is mounted on a wrist end of the glove, and wherein an outer end of the flexible rod is mounted on a fingertip of the glove.
The soft robotic glove of claim 1, wherein the at least one actuator comprises:

a first tube;

a pair of plugs, each plug fitted inside a respective end of the first tube;

a pair of fittings, each fitting fitted on a respective end of the first tube;

a pair of second tubes, each second tube fitted on a respective end of the pair of fittings opposite of the first tube,

wherein the flexible rod is inserted in an outer tube of the pair of second tubes;

a pair of pistons, each piston fitted in a respective second tube of the pair of second tubes;

a wire rope fitted in the first tube and the pair of second tubes, the wire rope passing through the pair of plugs, the pair of pistons, and an inner end of the flexible rod; and

a pair of wire rope sleeves, one wire rope sleeve connected to each end of the wire rope at an outside of each respective piston of the pair of pistons.
The soft robotic glove of claim 4, wherein the wire rope is elastic.
The soft robotic glove of claim 4, wherein the wire rope is inelastic.
The soft robotic glove of claim 4, wherein a material inside the each second tube of the pair of second tubes is configured to reduce friction between each respective piston of the pair of pistons and each respective second tube of the pair of second tubes.
The soft robotic glove of claim 4, wherein the flexible fabric comprises a sheath within which the flexible rod slides within the flexible fabric.
A method of extending a flexible rod of a soft robotic glove, the method comprising:

providing a soft robotic glove as described in claim 4; and

providing compressed air to a port of one fitting of the pair of fittings to push a piston of the pair of pistons towards the flexible rod and causing the flexible rod extend from the outer tube,

wherein the other fitting of the pair of fittings is subjected to an ambient atmosphere or a pressure lower than a pressure of the compressed air.
A method of retracting a rod of a soft robotic glove, the method comprising:

providing a soft robotic glove as described in claim 4; and

providing compressed air to a port of one fitting of the pair of fittings to push a piston of the pair of pistons away from the flexible rod and causing the flexible rod to retract into the outer tube,

wherein the other fitting of the pair of fittings is subjected to an ambient atmosphere or a pressure lower than a pressure of the compressed air.