Wireless actuators

Patent metadata

Field	Value
Publication number	US-11892015-B2
Application number	US-201917284243-A
Country	US
Kind code	B2
Filing date	Oct 10, 2019
Priority date	Oct 10, 2018
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

A method of performing wireless actuation by inductive heating of magnetic particles. The method provides a bladder having an inner surface and an outer surface, the inner surface forming an interior area, the bladder configured to expand or retract so as to change an area of the interior area, (ii) a plurality of magnetic particles suspended in a fluid medium and disposed within the interior area, and (iii) a sleeve disposed on the outer surface of the bladder. The method excites the plurality of magnetic particles by application of an alternating magnetic field to which the particles reaction. The method causes, by the excited magnetic particles, a phase transition to the fluid medium within the interior area which causes the bladder to expand, such that the sleeve confining the bladder generates actuation from the expansion or retraction of the bladder.

First claim

What is claimed is:

1. A wireless actuation system, the system comprising
a device for wireless actuation, the device comprising:
a bladder having an inner surface and an outer surface, the inner surface forming an interior area, the bladder configured to expand or retract so as to change an area of the interior area;
a plurality of magnetic particles suspended in a fluid medium and disposed within the interior area, the plurality of magnetic particles configured to react to an alternating magnetic field which causes a phase transition to the fluid medium within the interior area and causes the bladder to expand; and
a sleeve disposed on the outer surface of the bladder, the sleeve configured to confine the bladder so as to generate actuation from the expansion or retraction of the bladder; and
a magnetic field generator configured to generate an alternating magnetic field.

2. The system of claim 1 , wherein the plurality of magnetic particles are configured to heat in reaction to the alternating magnetic field and the heat of the magnetic particles causes the phase transition to the fluid medium.

3. The system of claim 2 , wherein the plurality of magnetic particles are heated by the alternating magnetic field inducing a current within a set of the plurality of magnetic particles.

4. The system of claim 2 , wherein the phase transition includes generating steam within the interior area by the heated magnetic particles boiling the fluid medium within the interior area, such that the steam causes the bladder to expand within the sleeve.

5. The system of claim 4 , wherein the bladder is expanded due to pressure caused by the steam within the interior area, and due to confinement of the bladder within the sleeve, the expansion or retraction of the bladder generates the actuation.

6. The system of claim 1 , wherein the sleeve is made of braided carbon fiber.

7. The system of claim 1 , wherein the plurality of magnetic particles are coated with a coating material to prevent agglomeration.

8. The system of claim 7 , wherein the coating material includes methoxy-PEG-silane.

9. A method of wireless actuation, the method comprising:
providing (i) a bladder having an inner surface and an outer surface, the inner surface forming an interior area, the bladder configured to expand or retract so as to change an area of the interior area, (ii) a plurality of magnetic particles suspended in a fluid medium and disposed within the interior area, and (iii) a sleeve disposed on the outer surface of the bladder;
exciting the plurality of magnetic particles by application of an alternating magnetic field to which the plurality of magnetic particles react; and
causing, by the excited magnetic particles, a phase transition to the fluid medium within the interior area which causes the bladder to expand, such that the sleeve confining the bladder generates actuation from the expansion or retraction of the bladder.

10. The method of claim 9 , wherein exciting includes heating the magnetic particles in reaction to the alternating magnetic field and the heat of the magnetic particles causes the phase transition to the fluid medium.

11. The method of claim 9 , wherein the plurality of magnetic particles are heated by the alternating magnet field inducing a current within a set of the plurality of magnetic particles.

12. The method of claim 9 , wherein the phase transition includes generating steam in the interior area by the heated magnetic particles boiling the fluid medium in the interior area, such that the steam causes the bladder to expand within the sleeve.

13. The method of claim 12 , wherein the bladder is expanded due to pressure caused by the steam within the interior area, and due to confinement of the bladder within the sleeve, the expansion or retraction of the bladder generates the actuation.

14. The method claim 9 , wherein the plurality of magnetic particles are microparticles or nanoparticles.

15. The method of claim 9 , wherein the plurality of magnetic particles comprise one or more of: iron, iron oxide, nickel, nickel oxide, cobalt and/or cobalt oxide.

16. The method of claim 9 , wherein the plurality of magnetic particles comprise Fe 3 O 4 .

17. The method of claim 9 , wherein the sleeve is made of braided carbon fiber.

18. The method of claim 9 , wherein the plurality of magnetic particles are coated with a coating material to prevent agglomeration.

19. The method of claim 18 , wherein the coating material includes methoxy-PEG-silane.

Assignees

• Massachusetts Inst Technology

Inventors

• Mirvakili Seyed M
• Hunter Ian W

Classifications

• F15B15/103 Primary

  using inflatable bodies that contract when fluid pressure is applied, e.g. pneumatic artificial muscles or McKibben-type actuators · CPC title

• F15B15/1485

  Special measures for cooling or heating · CPC title

• F15B21/065

  Use of electro- or magnetosensitive fluids, e.g. electrorheological fluid · CPC title

• H01F1/445

  the magnetic component being a compound, e.g. Fe3O4 (H01F1/447 takes precedence) · CPC title

• H01F1/447

  characterised by magnetoviscosity, e.g. magnetorheological, magnetothixotropic, magnetodilatant liquids (electrorheological fluids C10M171/001) · CPC title