Granted Patent B2

US 12,441,468 · App. 18/514,625 · Granted Oct 14, 2025

Inventors: Xiaozhou Fan (Pasadena, CA); Kenneth Breuer (Newton, MA)

Assignee: Brown University

B64C33/02

Abstract

Claims (30)

1. A three degrees-of freedom robotic flapper comprising:

a fuselage, the fuselage housing motors and driving trains;

a left wing attached to the fuselage; and

a right wing attached to the fuselage, the left wing and the right wing configured to perform a wing flapping motion, a wing twisting motion and a wing folding motion, the wing twisting motion actuated by a Bowden cable.

2. The three degrees-of freedom robotic flapper of claim 1 wherein the left wing comprises:

a handwing; and

an armwing.

3. The three degrees-of freedom robotic flapper of claim 2 wherein the right wing comprises:

a handwing; and

an armwing.

4. The three degrees-of freedom robotic flapper of claim 3 wherein the motors and driving trains housed in the fuselage include two four-bar linkages, driven by two servomotors, in which one of the two servomotors controls a wing flapping movement of the armwings of the left wing and the right wing, and the other of the two servomotors controls a wing folding movement of the right wing handwing relative to the right wing armwing and the left wing handwing relative to the left wing armwing.

5. The three degrees-of freedom robotic flapper of claim 4 wherein the wing flapping motion is driven by the four-bar linkage mechanism configured to spin the motor continuously in one direction, which raises up and pulls down the entire wing.

6. The three degrees-of freedom robotic flapper of claim 5 wherein the wing folding motion is realized by a timing belt transmission, where an outboard portion of the wing is fixed with a spool, and rotates with respect to an inner portion of the wing.

7. The three degrees-of freedom robotic flapper of claim 5 wherein a rotating crank is configured to pull down and raise up a ball-link linkage, the ball-link linkage is connected to a rocker that is fixed with the wing.

8. The three degrees-of freedom robotic flapper of claim 6 wherein the motor outputs reciprocal motion configured to rotate a driving spool back and forth; and

through a transmission of the timing belt, the driven spool sits in a junction between in- and outboard wing that rotates an outboard wing with respect to its inner portion.

9. The three degrees-of freedom robotic flapper of claim 4 wherein a third motor is used to deliver the wing twisting configured to rotate reciprocatively, and through an antagonistic strings pulling and releasing, a last wing section pitches up and down, connected with flexible rods, a second from last wing section would follow, but with a smaller angle, and a third section with an even smaller degree.

10. The three degrees-of freedom robotic flapper of claim 4 wherein a first servomotor controls wing flapping and a movement of an armwing.

11. The three degrees-of freedom robotic flapper of claim 10 wherein a second servomotor controls wing folding and a movement of a handwing relative to the armwing.

12. The three degrees-of freedom robotic flapper of claim 11 wherein a third servomotor controls wing twisting and a varying pitching angle of the wing section along the wingspan.

13. A method of flapping wings on a robotic platform comprising:

providing a fuselage housing motors and driving trains;

providing a left wing attached to the fuselage;

providing a right wing attached to the fuselage; and

performing a wing flapping motion, a wing twisting motion and a wing folding motion, the wing twisting motion is actuated by a Bowden cable, the wing folding motion and the wing twisting working in synergy by alleviating negative lift during a late upstroke, and producing more thrust in a throughout cycle.

14. The method of flapping wings on a robotic platform of claim 13 wherein, when taking off climbing flight, the fuselage pitches up, and the wing flapping motion, the wing twisting motion and the wing folding motion work together to achieve high lift and low thrust.

15. The method of flapping wings on a robotic platform of claim 14 wherein, to maximize lift, an amplitude of the folding motion is controlled to be approximately 75 degrees, or until a left wing tip and a right wing tip almost meet under the fuselage to affect an air jet.

16. The method of flapping wings on a robotic platform of claim 15 wherein further comprising actuating the wing twisting motion to minimize negative lift felt during an upstroke of the right wing and the left wing, producing large positive lift due to large wing twisting angles.

17. The method of flapping wings on a robotic platform of claim 13 , wherein during cruise condition, the flapping motion is set to approximately 50 degrees, and a twisting of the right wing and the left wing actuated throughout a stroke to orient the right wing and the left wing to produce thrust.

18. The method of flapping wings on a robotic platform of claim 13 , wherein during a descending flight the wing twisting motion is pronounced during upstroke such that a ventral side of the right wing and the left wing is almost facing upward.

Assignments (1)

Continuity (2)

References Cited (141)

Cited By (1)

US 12,650,362