Continuous production of muscle fibers

1. A method of producing an actuator device, the method comprising:

twisting a muscle fiber;

coiling the twisted muscle fiber about a mandrel;

securing the muscle fiber onto the mandrel using a rotating belt that extends around the mandrel;

heating the muscle fiber to a predetermined temperature using a heater; and

removing the coiled muscle fiber from the mandrel,

wherein the twisting, coiling, securing, heating, and removing is a process that is continued until the muscle fiber is a desired length, and

wherein the heater is operably connected to the mandrel such that the temperature of the mandrel is raised to the predetermined temperature.

2. The method of claim 1 , wherein the muscle fiber comprises a polymer fiber selected from the group consisting of nylon, polyethylene, polyvinylidene fluoride, and combinations thereof.

3. The method of claim 1 , wherein the muscle fiber comprises carbon nanotubes (CNT).

4. A system for continuous manufacturing of an actuator device, the system comprising:

a mandrel operably connected to a motor;

a rotating belt that extends around the mandrel; and

a heater,

wherein a twisted muscle fiber is coiled around the mandrel using the motor and secured by the rotating belt,

wherein the heater heats the muscle fiber to a predetermined temperature, and

wherein the heater is operably connected to the mandrel such that the temperature of the mandrel is raised to the predetermined temperature.

5. The system of claim 4 , wherein the muscle fiber comprises a polymer fiber selected from the group consisting of nylon, polyethylene, polyvinylidene fluoride, and combinations thereof.

6. The system of claim 4 , wherein the muscle fiber comprises carbon nanotubes (CNT).

7. An apparatus for continuously coiling artificial muscles, the apparatus comprising:

an arbor spool;

an arbor wire that is wound around the arbor spool, wherein the arbor spool releases the arbor wire at a rate in a rate range of 1 cm/min and 50 cm/min;

a first motor that rotates the arbor spool;

an arbor tension sensor that:

measures tension on the arbor wire as the arbor wire is released out of the arbor spool, and

automatically adjusts the tension on the arbor wire in response to sensing that the tension on the arbor wire is out of the load range;

a plurality of pulleys that apply the tension on the arbor wire;

a precursor muscle fiber comprising:

a core fiber; and

a conductive wire twisted and wrapped around the core fiber;

a muscle spool that holds the precursor muscle fiber, wherein a round-per-minute rate of the muscle spool is proportional to a velocity of the arbor wire divided by a diameter of the precursor muscle fiber;

a second motor that pulls the precursor muscle fiber from the muscle spool;

a muscle tensioner that maintains tension on the precursor muscle fiber as the precursor muscle fiber is being wound around the arbor wire, wherein the tension on the precursor muscle fiber is in a tension range of 1 N to 50 N;

a coil spool that holds the arbor wire after the precursor muscle fiber has been wrapped around the arbor wire;

a third motor that rotates the coil spool;

a linear stage actuator that moves the coil spool back and forth and evenly places the arbor wire along a width of the coil spool; and

an oven or a furnace for annealing the coil spool along with the precursor muscle fiber wrapped around the arbor wire,

wherein the core fiber may be a twisted core fiber or an untwisted core fiber, and

wherein the apparatus coils the precursor muscle fiber around the arbor wire.

8. The apparatus of claim 7 , wherein the arbor wire is selected from the group consisting of stainless steel, tungsten, nichrome, carbon nanotube yarn, and combinations thereof.

9. The apparatus of claim 7 , wherein the core fiber is selected from the group consisting of nylon, polyethylene, polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene, polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), liquid-crystal polymer (LCP), aramid, a multifilament yarn spun from liquid crystal polymer, carbon nanotube yarn, and combinations thereof.

10. The apparatus of claim 7 , wherein

the core fiber is nylon,

the annealing is at a temperature in a temperature range of 150° C. to 200° C.,

the annealing is for a time in a time range of 0.5 hr to 3 hr.

11. A method for manufacturing a coiled muscle, the method comprising:

pulling an arbor wire from an arbor spool;

passing the arbor wire around a pulley and through an arbor tension transducer that measures a tension of the arbor wire;

pulling a precursor muscle fiber from a muscle spool and through a tensioner, the precursor muscle fiber comprising:

a core fiber; and

a conductive wire wrapped around the core fiber;

wrapping the precursor muscle fiber around the arbor wire that has passed the arbor tension transducer to produce a coiled muscle fiber;

winding the coiled muscle fiber onto a coil spool;

annealing the coiled muscle fiber around the coil spool in an oven or a furnace;

removing the coiled muscle fiber around the coil spool from the oven or the furnace; and

removing the arbor wire from the coiled muscle fiber to create a coiled muscle,

wherein the core fiber may be a twisted core fiber or an untwisted core fiber,

wherein a round-per-minute rate of the muscle spool is proportional to a velocity of the arbor wire divided by a diameter of the precursor muscle fiber.

12. The method of claim 11 , wherein the arbor wire is any of stainless steel, tungsten, nichrome, or carbon nanotube yarn.

13. The method of claim 11 , wherein the core fiber is selected from the group consisting of nylon, polyethylene, polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene, polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), liquid-crystal polymer (LCP), aramid, a multifilament yarn spun from liquid crystal polymer, carbon nanotube yarn, and combinations thereof.

14. The method of claim 11 , wherein

the core fiber is nylon,

the annealing is at a temperature in a temperature range of 150° C. to 200° C., and

the annealing is for a time in a time range of 0.5 hr to 3 hr.

15. The method of claim 11 , wherein the core fiber is the twisted core fiber and the coiled muscle is homochiral and a direction of wrapping the precursor muscle fiber around the arbor wire is same as a direction of twisting the core fiber and a direction of wrapping the conductive wire around the core fiber.

16. The method of claim 11 , wherein the core fiber is the twisted core fiber and the coiled muscle is heterochiral and a direction of wrapping the precursor muscle fiber around the arbor wire is opposite to a direction of twisting the core fiber and a direction of wrapping the conductive wire around the core fiber.