Structural Design and Kinematic Modeling of Highly Biomimetic Flapping-Wing Aircraft with Perching Functionality

Abstract

Birds use their claws to perch on branches, which helps them to recover energy and observe their surroundings; however, most biomimetic flapping-wing aircraft can only fly, not perch. This study was conducted on the basis of bionic principles to replicate birds' claw and wing movements in order to design a highly biomimetic flapping-wing aircraft capable of perching. First, a posture conversion module with a multi-motor hemispherical gear structure allows the aircraft to flap, twist, swing, and transition between its folded and unfolded states. The perching module, based on helical motion, converts the motor's rotational movement into axial movement to extend and retract the claws, enabling the aircraft to perch. The head and tail motion module has a dual motor that enables the aircraft's head and tail to move as flexibly as a bird's. Kinematic models of the main functional modules are established and verified for accuracy. Functional experiments on the prototype show that it can perform all perching actions, demonstrating multi-modal motion capabilities and providing a foundation upon which to develop dynamics models and control methods for highly biomimetic flapping-wing aircraft with perching functionality.

Keywords: flapping-wing aircraft; highly biomimetic; kinematics model; perching function.

Figure 1

The multi-modal movement patterns of birds.

Figure 2

Flight-to-perching posture characteristic diagram.

Figure 3

Perching-to-takeoff posture characteristic diagram.

Figure 4

Schematic diagram of the structure and main movement implementation of a flapping-wing aircraft with perching function.

Figure 5

The components of the head motion module (1: pitch swing rocker; 2: fixed sleeve; 3: pitch swing drive rod; 4: slider; 5: yaw swing rocker; 6: connecting pin; 7: yaw swing drive rod; 8: pitch servo; 9: yaw servo).

Figure 6

The components of the posture conversion module (1: base; 2: posture conversion link; 3: posture conversion crank; 4: rotational drive rod; 5: connecting plate; 6: folding drive rod; 7: folding link; 8: V-shaped rocker; 9: frame plate; 10: mid-section wing; 11: main shaft; 12: connecting rod; 13: slide rail; 14: gear 1; 15: gear 2).

Figure 7

The structure diagram of the multi-segment flapping wing module (16: middle wing segment; 17: folding crank; 18: folding rocker; 19: connecting plate; 20: second outer wing segment; 21: feathers).

Figure 8

The structure diagram of the perching module (1: lower claw; 2: upper claw; 3: fixed base; 4: claw connector; 5: pusher frame; 6: side plate; 7: slide rod; 8: motor; 9: servo; 10: crank; 11: body connector).

Figure 9

Diagram of the connecting module structure (1: posture conversion module connecting rod; 2: front circular plate; 3: battery fixing plate; 4: perching module connecting rod; 5: rear circular plate; 6: load mounting plate; 7: head connecting rod; 8: tail connecting rod).

Figure 10

Comparison of the perching and takeoff stages of the flapping-wing aircraft model with the corresponding hawk postures.

Figure 11

The schematic diagram (a) and motion parameters (b) of the flapping module. The red box indicates the mechanism corresponding to the motion parameters.

Figure 12

The schematic diagram (a) and motion parameters (b) of the folding module. The red box indicates the mechanism corresponding to the motion parameters.

Figure 13

The schematic diagram (a) and motion parameters (b) of the bending module. The red box indicates the mechanism corresponding to the motion parameters.

Figure 14

The schematic diagram (a) and motion parameters (b) of the perching module.

Figure 15

The schematic diagram (a) and motion parameters (b) of the head motion module. The letters in the schematic diagram (left) correspond to the motion parameters (right).

Figure 16

ADAMS model of flapping wing aircraft with perching function.

Figure 17

The simulation results of each module.

Figure 18

The prototype of the flapping wing aircraft with perching function.

Figure 19

The scenario for the experiment.

Figure 19

The scenario for the experiment.

Figure 20

The motion capture device for the experiment.

Figure 21

The installation locations for the fluorescent balls.

Figure 22

Comparison of the key postures of the flapping-wing aircraft and the corresponding hawk perching postures.

Figure 23

Schematic diagram of key motion parameters during perching and takeoff processes.

Figure 24

Time-varying curves of various motion parameters during the process of perching (a) and takeoff (b).