A variable stiffness actuator and soft exoskeleton system

Abstract

The present application provides a variable stiffness actuator and a soft exoskeleton system, the variable stiffness actuator comprising an air bag, a spring piece assembly and a driving assembly, the spring piece assembly comprising at least two sub-spring pieces capable of bending and deforming along a first direction, the sub-spring pieces being accommodated in the air bag in a bent manner; the two ends of the sub-spring pieces along the first direction are respectively provided with coaxially arranged first holes and second holes, and the middle parts of the adjacent sub-spring pieces along the first direction are connected to each other; the driving assembly comprises a motor, a first rotating shaft and a second rotating shaft, the first rotating shaft is arranged in the first hole, the second rotating shaft is arranged in the second hole, and at least one of the first rotating shaft and the second rotating shaft is connected to the motor shaft of the motor. The present application provides a variable stiffness actuator, by controlling the vacuum degree inside the air bag and the unfolding angle of the sub-spring pieces, the stiffness adjustment of the actuator can be realized; the actuator has a simple structure, a small weight, can be applied to the joint part of the soft exoskeleton, has a small pressure load on the user, has a flexible contact with the joint of the user, and has a good comfort.

Description

Technical Field

[0001] This invention relates to the field of actuators and exoskeleton robot technology, and more specifically, to a variable stiffness actuator and a soft exoskeleton system. Background Technology

[0002] In recent years, with the development of human-computer interaction technology, the safety and comfort of robots have received increasing attention. Soft exoskeleton robots exert less pressure on external objects and are less likely to cause damage to them. As a new type of flexible robot, soft exoskeleton robots have broad application prospects in the field of human-computer interaction.

[0003] In existing technologies, joint actuators of exoskeleton robots typically employ rigid actuators, using motors as the source of constraint force. This force is transmitted to the joint to be constrained through rigid mechanical structures such as linkages, thereby hindering the joint's movement and achieving the effect of constraining the joint's posture. However, rigid actuators also have the following drawbacks: they are heavy, exert a large pressure load on the user, and their rigid contact with the human joint results in poor comfort. Therefore, it is necessary to develop a variable stiffness flexible actuator. Summary of the Invention

[0004] This invention provides a variable stiffness actuator to solve the technical problems of existing rigid actuators, such as large weight, high pressure load on users, and poor comfort due to rigid contact with human joints.

[0005] This invention provides a variable stiffness actuator, comprising an airbag, a spring assembly, and a drive assembly. The spring assembly includes at least two bullet-shaped pieces capable of bending and deforming along a first direction, the bullet-shaped pieces being bent and accommodated within the airbag. Each bullet-shaped piece has a first hole and a second hole at its two ends along the first direction, the first hole and the second hole being coaxially arranged. Adjacent bullet-shaped pieces are connected to each other at their midpoints along the first direction. The drive assembly includes a motor, a first rotating shaft, and a second rotating shaft. The first rotating shaft is disposed in the first hole, and the second rotating shaft is disposed in the second hole. At least one of the first rotating shaft and the second rotating shaft is connected to the motor shaft of the motor. The motor drives the first rotating shaft and / or the second rotating shaft to rotate the bullet-shaped pieces to adjust the overlap area between adjacent bullet-shaped pieces. The airbag is configured such that, if a vacuum is drawn, the airbag conforms to the inner and outer surfaces of the bullet-shaped pieces, constraining adjacent bullet-shaped pieces from relative movement.

[0006] This invention provides a variable stiffness actuator. On the one hand, the stiffness of the actuator can be adjusted by controlling the vacuum level inside the airbag and the unfolding angle of the drive bullet. On the other hand, the actuator has a simple structure and light weight, and can be applied to the joints of soft exoskeletons. It exerts less pressure load on the user, makes flexible contact with the user's joints, and provides better comfort.

[0007] Furthermore, the airbag is connected to an air outlet pipe, which is equipped with a vacuum valve. The vacuum valve is used to control the opening and closing of the air outlet pipe, with one end connected to the cavity of the airbag and the other end connected to a vacuum pump.

[0008] Alternatively, the airbag is connected to an inlet pipe and an outlet pipe. The inlet pipe is equipped with an inflation valve, which controls the opening and closing of the inlet pipe. One end of the inflation valve is connected to the cavity of the airbag, and the other end is connected to an air source. The outlet pipe is equipped with a vacuum valve, which controls the opening and closing of the outlet pipe. One end of the vacuum valve is connected to the cavity of the airbag, and the other end is connected to a vacuum pump.

[0009] Furthermore, at least two drive plates are fixedly provided on the first rotating shaft along the axial direction, and the drive plates are respectively fixedly connected to the bullet pieces;

[0010] And / or, at least two of the drive plates are fixedly provided on the second rotating shaft along the axial direction, and the drive plates are respectively fixedly connected to the bullet pieces.

[0011] Furthermore, the surface of the bullet fragments is provided with granules or uneven patterns. This design increases the friction between the bullet fragments, preventing them from sliding relative to each other after the airbag is evacuated.

[0012] Furthermore, the bullet fragment is made of elastic plastic.

[0013] Furthermore, the shape of the bullet fragment in its free state is a semi-circular arc, an ellipse, or a strip-shaped rectangle.

[0014] Furthermore, adjacent bullet fragments are provided with connecting pieces at their midpoints along the first direction. This arrangement restricts the rotational displacement of the bullet fragments and prevents any adjacent bullet fragments from having no overlapping area.

[0015] A second aspect of the present invention provides a soft exoskeleton system, including an exoskeleton body and a variable stiffness actuator as described in any of the preceding claims, the exoskeleton body having a plurality of joints, the joints including a shoulder joint, an elbow joint, a wrist joint, a finger joint, a hip joint, a knee joint and / or an ankle joint, the variable stiffness actuator being disposed at the joints.

[0016] The soft exoskeleton system provided by this invention has a simple structure, light weight, low pressure load on the user, and flexible contact with the user's joints by setting variable stiffness actuators at the joints, thereby improving the user's comfort.

[0017] Furthermore, the variable stiffness actuator is bonded to the joint. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a variable stiffness actuator provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of an elastic component in a variable stiffness actuator provided by an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the free state of an elastic component in a variable stiffness actuator provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of a soft exoskeleton system provided in an embodiment of the present invention;

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Shoulder joint; 2. Elbow joint; 3. Wrist joint; 4. Finger joint; 5. Hip joint; 6. Knee joint; 7. Ankle joint; 10. Airbag; 20. Shrapnel assembly; 21. Bullet shrapnel; 211. First hole; 212. Second hole; 22. Connecting piece. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figure 1-4 Specific embodiments of the present invention will be described in detail below.

[0025] See appendix Figure 1 , Figure 2 and Figure 3This invention provides a variable stiffness actuator, including an airbag 10, a spring assembly 20, and a drive assembly. The spring assembly 20 includes at least two bullet pieces 21 capable of bending and deforming along a first direction, which are bent and accommodated within the airbag 10. Each bullet piece 21 has a first hole 211 and a second hole 212 at its two ends along the first direction, which are coaxially arranged. Adjacent bullet pieces 21 are connected to each other at their middle portions along the first direction. The drive assembly includes a motor, a first rotating shaft, and a second rotating shaft. The first rotating shaft is located in the first hole 211, and the second rotating shaft is located in the second hole 212. At least one of the first and second rotating shafts is connected to the motor shaft of the motor. The motor drives the first rotating shaft and / or the second rotating shaft to rotate the bullet pieces 21 to adjust the overlap area between adjacent bullet pieces 21. The airbag 10 is configured such that, if a vacuum is drawn, the airbag 10 fits against the inner and outer surfaces of the bullet pieces 21, constraining the adjacent bullet pieces 21 from relative movement.

[0026] It should be noted that the size of the airbag 10 along the first direction is smaller than the size of the bullet fragment 21 along the first direction in its free state. The size of the bullet fragment 21 along the first direction refers to the length of the bullet fragment 21.

[0027] It should be noted that when the airbag 10 is not evacuated, there is a gap between the inner and outer surfaces of the airbag 10 and the bullet piece 21. Under the drive of the motor, the bullet piece 21 can rotate and adjust the overlapping area between adjacent bullet pieces 21. When the airbag 10 is evacuated, the inner and outer surfaces of the airbag 10 and the bullet piece 21 are in contact, and there is no relative movement between adjacent bullet pieces 21.

[0028] It should be noted that the greater the vacuum degree, the greater the negative pressure, and the greater the positive pressure of the airbag 10 on the inner and outer surfaces of the bullet fragment 21; the greater the overlap area between any adjacent bullet fragments 21, the greater the stiffness of the variable stiffness actuator.

[0029] It should be noted that the spring assembly 20 includes at least two bullet pieces 21, which are rotatable to adjust the deployment angle of the spring assembly 20. This variable stiffness actuator is applied to the joints of the soft exoskeleton system to constrain the joint angles of the soft exoskeleton.

[0030] It should be noted that by setting rotatable bullet pieces 21, the overlapping area between bullet pieces 21 can be changed under the driving action of the motor, and the unfolding angle of bullet pieces 21 can be changed; by inflating or deflating the airbag 10, "softening" and "hardening" can be achieved. When inflated or not deflated, there is a gap between the inner and outer surfaces of the airbag 10 and the bullet pieces 21, and the bullet pieces 21 can move relative to each other; when deflating, the airbag 10 is attached to the inner and outer surfaces of the bullet pieces 21, so that the bullet pieces 21 cannot move relative to each other, and become a rigid structure.

[0031] This invention provides a variable stiffness actuator. On the one hand, the stiffness of the actuator can be adjusted by controlling the vacuum level inside the airbag 10 and the unfolding angle of the drive bullet 21. On the other hand, the actuator has a simple structure and light weight, and can be applied to the joints of soft exoskeletons. It exerts less pressure load on the user, makes flexible contact with the user's joints, and provides better comfort.

[0032] In one embodiment of the present invention, the airbag is connected to an air outlet pipe, which is equipped with a vacuum valve. The vacuum valve is used to control the opening and closing of the air outlet pipe. One end of the valve is connected to the cavity of the airbag 10, and the other end is connected to a vacuum pump.

[0033] In another embodiment of the present invention, the airbag 10 is connected to an air inlet pipe and an air outlet pipe. The air inlet pipe is equipped with an inflation valve, and the air outlet pipe is equipped with a vacuum valve. The inflation valve is used to open and close the air inlet pipe, one end of which is connected to the cavity of the airbag 10 and the other end of which is connected to an air source. The vacuum valve is used to open and close the air outlet pipe, one end of which is connected to the cavity of the airbag 10 and the other end of which is connected to a vacuum pump.

[0034] It should be noted that the connection method between the first rotating shaft and the first hole 211 is not limited, and the connection method between the second rotating shaft and the second hole 212 is not limited; it can be a fixed connection or a pivot connection.

[0035] In this embodiment of the invention, the first rotating shaft is fixed in the first hole 211; the second rotating shaft is fixed in the second hole 212.

[0036] In one embodiment of the present invention, a first rotating shaft is pivotally connected to a first hole 211, and a second rotating shaft is pivotally connected to a second hole 212; at least two driving plates are fixedly provided on the first rotating shaft along the axial direction, and the driving plates are respectively fixedly connected to the bullet plate 21.

[0037] In another embodiment of the present invention, the first rotating shaft is pivotally connected to the first hole 211, and the second rotating shaft is pivotally connected to the second hole 212; at least two driving plates are fixedly provided on the second rotating shaft along the axial direction, and the driving plates are respectively fixedly connected to the bullet plate 21.

[0038] In other embodiments of the present invention, the first rotating shaft is pivotally connected to the first hole 211, and the second rotating shaft is pivotally connected to the second hole 212; at least two driving plates are fixedly provided on the first rotating shaft along the axial direction, and the driving plates are respectively fixedly connected to the bullet plate 21; at least two driving plates are fixedly provided on the second rotating shaft along the axial direction, and the driving plates are respectively fixedly connected to the bullet plate 21.

[0039] In this embodiment of the invention, the surface of the bullet fragment 21 is provided with particles or uneven patterns. This design increases the friction between the bullet fragments 21, preventing them from sliding relative to each other after the airbag 10 is evacuated.

[0040] In this embodiment of the invention, the bullet fragment 21 is made of elastic plastic.

[0041] Preferably, the bullet fragment 21 is made of PET elastic plastic.

[0042] In this embodiment of the invention, the bullet fragment 21 has a semi-circular arc shape, an ellipse shape, or a strip-shaped rectangle in its free state.

[0043] See appendix Figure 2 In this embodiment of the invention, a connecting piece 22 is provided at the middle of adjacent bullet pieces 21 along a first direction. It should be noted that the connecting piece 22 is foldable. This arrangement restricts the rotational displacement of the bullet pieces 21, preventing any adjacent bullet pieces 21 from having no overlapping area.

[0044] See appendix Figure 4 A second aspect of the present invention provides a soft exoskeleton system, including an exoskeleton body and a variable stiffness actuator of any of the above. The exoskeleton body has multiple joints, including a shoulder joint 1, an elbow joint 2, a wrist joint 3, a finger joint 4, a hip joint 5, a knee joint 6, and / or an ankle joint 7. The variable stiffness actuator is located at any of the joints.

[0045] The soft exoskeleton system provided in this invention has a simple structure, light weight, low pressure load on the user, and flexible contact with the user's joints by setting variable stiffness actuators at the joints, thereby improving the user's comfort.

[0046] In this embodiment of the invention, the variable stiffness actuator is bonded to any joint. It should be noted that the bonding method can be adhesive or Velcro.

[0047] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A variable stiffness actuator, characterized in that, The system includes an airbag (10), a spring assembly (20), and a drive assembly. The spring assembly (20) includes at least two bullet pieces (21) capable of bending and deforming along a first direction. The bullet pieces (21) are bent and accommodated within the airbag (10). Each bullet piece (21) has a first hole (211) and a second hole (212) at both ends along the first direction, and the first hole (211) and the second hole (212) are coaxially arranged. Adjacent bullet pieces (21) are connected to each other at the middle along the first direction. The drive assembly includes a motor, a first rotating shaft, and a second rotating shaft. Two rotating shafts, the first rotating shaft is located in the first hole (211), and the second rotating shaft is located in the second hole (212). At least one of the first rotating shaft and the second rotating shaft is connected to the motor shaft of the motor. The motor drives the first rotating shaft and / or the second rotating shaft to rotate the bullet piece (21) to adjust the overlap area between adjacent bullet pieces (21). The airbag (10) is configured such that, if a vacuum is drawn, the airbag (10) fits against the inner and outer surfaces of the bullet piece (21) to constrain the adjacent bullet pieces (21) from relative movement.

2. The variable stiffness actuator according to claim 1, characterized in that, The airbag is connected to an air outlet pipe, and the air outlet pipe is equipped with a vacuum valve. The vacuum valve is used to control the opening and closing of the air outlet pipe. One end of the valve is connected to the cavity of the airbag (10), and the other end is connected to a vacuum pump. Alternatively, the airbag (10) is connected to an air inlet pipe and an air outlet pipe. The air inlet pipe is equipped with an inflation valve, which is used to control the opening and closing of the air inlet pipe. One end of the inflation valve is connected to the cavity of the airbag (10), and the other end is connected to an air source. The air outlet pipe is equipped with a vacuum valve, which is used to control the opening and closing of the air outlet pipe. One end of the vacuum valve is connected to the cavity of the airbag (10), and the other end is connected to a vacuum pump.

3. The variable stiffness actuator according to claim 1, characterized in that, The first rotating shaft is fixed in the first hole (211); the second rotating shaft is fixed in the second hole (212).

4. The variable stiffness actuator according to claim 1, characterized in that, The first rotating shaft is pivotally connected to the first hole (211), and the second rotating shaft is pivotally connected to the second hole (212); The first rotating shaft is fixedly provided with at least two driving plates along the axial direction, and the driving plates are respectively fixedly connected to the bullet plate (21); and / or, the second rotating shaft is fixedly provided with at least two driving plates along the axial direction, and the driving plates are respectively fixedly connected to the bullet plate (21).

5. The variable stiffness actuator according to claim 1, characterized in that, The surface of the bullet fragment (21) is provided with granules or uneven patterns.

6. The variable stiffness actuator according to claim 1, characterized in that, The bullet fragment (21) is made of elastic plastic.

7. The variable stiffness actuator according to claim 1, characterized in that, The bullet fragment (21) has a semi-circular arc, an ellipse, or a strip-shaped rectangle in its free state.

8. The variable stiffness actuator according to claim 1, characterized in that, The adjacent bullet pieces (21) are provided with connecting pieces (22) at the middle of the first direction.

9. A soft exoskeleton system, characterized in that, The exoskeleton body includes an exoskeleton body and a variable stiffness actuator as described in any one of claims 1-8, the exoskeleton body having a plurality of joints including a shoulder joint (1), an elbow joint (2), a wrist joint (3), a finger joint (4), a hip joint (5), a knee joint (6) and / or an ankle joint (7), the variable stiffness actuator being disposed at any of the joints.

10. The soft exoskeleton system of claim 9, wherein the variable stiffness actuator is bonded to any of the joints.

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