Patent ID: 12241487

DETAILED DESCRIPTION

In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following detailed description of the invention is provided in conjunction with specific embodiments. It should be understood that specific embodiments described here are for the purpose of explaining the invention and are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that terms such as “vertical,” “horizontal,” “longitudinal,” “front,” “rear,” “left,” “right,” “up,” “down,” “horizontal,” and similar directional or positional terms are based on the orientation or position relationship as shown in the drawings. These terms are used for descriptive purposes and do not imply that the devices or assembly must have specific orientations or positions. Therefore, they should not be construed as limitations on the present invention. The term “quantity” should also not be construed as limiting the present invention.

In the description of the present invention, it should be clarified that unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “joining” should be broadly interpreted. For example, it can refer to fixed connections, detachable connections, or integral connections; it can be mechanical connections, electrical connections, direct connections, or indirect connections through an intermediate medium. For those skilled in the art, these terms can be understood in specific contexts.

It should be understood that each component of a device or each step of a method can be described using device terminology or method terminology. Such terminology can be replaced as needed to provide clarity to the scope of the invention. As an example, it should be understood that all steps of a method can be disclosed as actions, means for taking the actions, or assembly causing the actions. Similarly, each component of a device can be disclosed as a physical element or an action facilitated by the physical element. For example, the disclosure of a “connector” should be understood to encompass the disclosure of the “connection” action, regardless of whether it is explicitly discussed. Conversely, if the “connection” action is disclosed, it should be understood to encompass the disclosure of a “connector” and even devices “used for connection.” These alternative terms for each component or step should be understood to be explicitly included in the specification.

Referring toFIG.1, in accordance with one embodiment of the present invention, a pneumatic and cable-driven hybrid artificial muscle is provided. It includes a pneumatic actuator1, a pneumatic pressure regulating assembly2, and a cable actuation assembly3. The pneumatic pressure regulating assembly2is connected to the pneumatic actuator1to adjust the air pressure in the pneumatic actuator1for controlling the pneumatic actuator1to extend or contract. The cable actuation assembly3is connected to the pneumatic actuator1for controlling the pneumatic actuator1to contract.

With the above technical solution, the artificial muscle provided by the present invention uses both pneumatic and cable drives. By leveraging the high rigidity of the pneumatic actuator1, it can provide substantial actuation force for joint movements. Simultaneously, the cable actuation assembly3can provide significant pulling force, effectively ensuring safety in human-machine interaction. As a wearable flexible exoskeleton driver, it provides sufficient bidirectional aiding force to disabled individuals.

FIGS.2to6illustrate more details of the pneumatic and cable-driven hybrid artificial muscle ofFIG.1.

The pneumatic actuator1includes an inner extending tube11, an outer extending tube12, a first sealing cap13, and a second sealing cap14.

The inner extending tube11is nested inside the outer extending tube12, preferably in a concentric arrangement. Each of the inner extending tube11and the outer extending tube12has a first end sealed to the first sealing cap13, and a second end sealed to the second sealing cap14, forming a sealed chamber15composed of the inner extending tube11, outer extending tube12, first sealing cap13, and second sealing cap14. The pneumatic pressure regulating assembly2is connected to the chamber15to adjust the air pressure in the pneumatic actuator1, thereby achieving the extension or contraction of the pneumatic actuator1.

When the air pressure in the chamber15increases, the pneumatic actuator1extends and generates a relatively large pushing force. When the air pressure in the chamber15decreases, the pneumatic actuator1contracts and generates a relatively low pulling force. In this case, the cable actuation assembly3is needed to provide additional pulling force.

Furthermore, to prevent the air pressure in the inner extending tube11from affecting the extension or contraction of the pneumatic actuator1, and to make it work more efficiently, a central through-hole141is provided on the second sealing cap14, allowing the inner extending tube11to be in connection with the external atmosphere.

Preferably, both the inner extending tube11and the outer extending tube12are made of corrugated tubes, which are able achieve synchronized extension and contraction. Preferably, the inner extending tube11and the outer extending tube12are integrally formed corrugated tubes. Preferably, both the inner extending tube11and the outer extending tube12are made of TPU material.

Alternatively, as shown inFIGS.7A and7B, the pneumatic actuator may be formed by stacking a plurality of doughnut shell-shaped chambers to have a multi-layer stacked doughnut structure.

Preferably, the first sealing cap13and the second sealing cap14are made of high-strength materials, such as glass-fiber-reinforced nylon material, and manufactured using a stereolithography3D printer.

The second sealing cap14includes a circular groove142on a side proximal to the first sealing cap13. The circular groove142is located between the inner extending tube11and the outer extending tube12and in connection with to the chamber15. The second sealing cap14further includes an air hole143opened at a side wall of the second sealing cap14and configured to connected to the circular groove142. The pneumatic pressure regulating assembly2is connected to pneumatic actuator1through the air hole143.

The pneumatic pressure regulating assembly2includes a high-pressure pump21connected to the chamber15for inflating the chamber15and a vacuum pump22connected to the chamber15for extracting air from the chamber15.

In one embodiment, the pneumatic and cable-driven hybrid artificial muscle further includes a pneumatic duct assembly4. The pneumatic duct assembly4comprises a main air duct41, a first branch air duct42, and a second branch air duct43. The main air duct41is connected to the air hole143. The high-pressure pump21is connected to the main air duct41through the first branch air duct42. The first branch air duct42has a high-pressure valve45. The vacuum pump22is connected to the main air duct41through the second branch air duct43. The second branch air duct43has a vacuum valve46.

Preferably, the pneumatic duct assembly4further includes a third branch air duct44. The main air duct41is connection with the external atmosphere through the third branch air duct4. The third branch air duct4has a relief valve47.

The cable actuation assembly3includes a flexible cable31and a motor32(e.g., a servo motor). The flexible cable31has one end fixed to the motor32and the other end fixed to a center of the first sealing cap13. The flexible cable31is configured to pass through the central through-hole141. To prevent the flexible cable31from interfering with the air passage through the central through-hole141, the diameter of the central through-hole141is at least twice the diameter of the flexible cable31.

When the motor32rotates in a direction of pulling the flexible cable31, the flexible cable31transmits tension to control contraction of the pneumatic actuator1. Conversely, when the motor32rotates in an opposite direction, the flexible cable31is slacken, and extension of the pneumatic actuator1is then mainly controlled by the pneumatic pressure regulating assembly2.

FIGS.8A to8Cillustrate the operation mechanism of the pneumatic and cable-driven hybrid artificial muscle.FIGS.9A to9Cshow different status of the pneumatic actuator in the pneumatic and cable-driven hybrid artificial muscle under different operation modes respectively.

Referring toFIG.8A, when the artificial muscle is required to provide a thrust, it is primarily controlled by the pneumatic pressure regulating assembly. The vacuum valve46and relief valve47are closed, and the high-pressure valve45is open. The high-pressure pump21generates a barotropic airflow through the high-pressure valve45to inflate the chamber15. As a result, the air pressure in the chamber15is increased and the pneumatic actuator extends (as shown inFIG.9A), generating a pushing force which constitute the entire required thrust. At this point, the motor32is in an inactive state, and the flexible cable31extends along with the extension of the pneumatic actuator.

When the artificial muscle is required to provide a pull, it is primarily controlled by the cable actuation assembly. In particular, the motor32is activated to retract the flexible cable31to generate a primary pulling force and the pneumatic pressure regulating assembly may be configured to operate in two cases.

Referring toFIG.8Bfor the first case. The high-pressure valve45and relief valve47are closed, while the vacuum valve46is open. The vacuum pump22is activated to generate a negative pressure airflow to evacuate air from the chamber15through the vacuum valve46. The air pressure inside the chamber15is reduced and the pneumatic actuator is compressed (as shown inFIG.9B) to generate an auxiliary pulling force, which is typically relatively small, in addition to the primary pulling force generated by the cable actuation assembly.

Referring toFIG.8Cfor the second case. The high-pressure valve45and vacuum valve46are closed, and the relief valve47is open, allowing the chamber15to be in connection with the external atmosphere. The pneumatic actuator is in an inactive state and does not generate any pulling force. Along with the retraction of the flexible cable31, the pneumatic actuator is compressed (as shown inFIG.9C) and the air inside the chamber15is discharged to external atmosphere through the relief valve47.

The artificial muscle provided by the present invention utilizes a dual-drive system, combining pneumatic and cable-driven mechanisms. By leveraging the inherent stiffness of the pneumatic actuator1, it can provide substantial actuation thrust for joint movements. Simultaneously, the cable actuation assembly3can supply significant driving pulling force. This effectively ensures safety in human-machine interactions and provides sufficient bidirectional aiding force for individuals with disabilities.

FIGS.10A to10Dshows a prototype of the pneumatic actuator of an artificial muscle according to one embodiment of the present invention.FIG.11Ashows a schematic diagram of an experimental setup for measuring forces generated by the artificial muscle protype under different operation modes.FIG.11Bshows a photo of the setup andFIG.11Cshows the measurement results. As shown, when only pneumatic actuator is used, the maximum achieved pulling force is less than 100 N. When cable actuation assembly is also involved, the maximum pulling force can be increased to about 270 N.FIG.12Ashows a schematic diagram of an experimental setup for measuring displacement achieved by the artificial muscle protype under different operation modes.FIG.12Bshows a photo of the setup andFIG.12Cshows the measurement results. As shown, the cable actuation assembly cannot produce positive (or forward) displacement, that is, it cannot generate any thrust for actuation, whereas the pneumatic actuator can produce a forward displacement of about 7 mm.

The foregoing description represents exemplary embodiments of the present invention. However, it should be understood that the scope of the present invention is not limited to these embodiments, and any variations or substitutions that would be readily apparent to those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.