Flapping-wing flight: design considerations - 6 Flashcards
What are the main features of bird-inspired and insect-inspired robots?
Bird-inspired robots are larger with lower flapping frequencies. Easier to construct, control and can potentially glide. Most cannot hover and are less maneuverable.
Insect-inspired are smaller with usually higher flapping frequencies (although they vary widely), usually hover capable, highly maneuverable good for confined spaces. Harder to construct and harder to control (usually unstable).
What are the most typical wing configurations used on FWMAVs? What are the advantages and
disadvantages of each?
Two-wing, four-wing (tandem or perpendicular), or x-wing(two, four, or eight pair).
Two-wing are simpler to design, study and construct and less complex. Lead to inertial oscillations inconvenient for sensors/cameras and has limited wing area.
Four-wing tandem allows additional lift production, precise control, and high maneuverability. But elaborate aerodynamics and control and mechanical complexity.
X-wing allows clap-and-fling exploitation at stroke reversal, opposite-phase flapping to reduce oscillations for more stable motions, and more wing area allows lower wing loading. Smaller flap amplitudes, though, as wing pairs flap in the sam plane.
What types of propulsive actuators are most commonly used for FWMAVs?
DC motors + transmission mechanism, piezo actuators + transmission, and electric (servo) motor direct drive.
What is the most common transmission mechanism used for FWMAVs?
Transmission flapping mechanism converts the rotary motion of the motor into the reciprocating motion of the flapping wings.
How is aerodynamic performance influenced by: (a) AR, (b) wing span, (c) wing twist?
(a) Increasing AR increases thrust to power ratio
(b) a bigger wing span produces more lift for the same flapping frequency
(c) wing twist can achieve better performance (more force and less power consumption)
What approaches can be used to improve FWMAV endurance?
Better wing design for more efficient aerodynamics, materials, manufacturing, structural design and power source.
What approaches can be used for FWMAV wing design?
Wing deformation, wing stiffeners, optimization-based design for wing geometry, membrane material, wing shape
What wing parameters is the flapping frequency influenced by?
Wing area and wing span - the bigger the wing, the lower the frequency for the same lift
What aerodynamic dimensionless number is the flapping amplitude related to?
AR and size
Explain the concept of model-based design.
If we have an initial platform, we can explore design change with model-based design by making targeted changes to the platform, doing a flight test, identifying full system models, and evaluating the dynamics and flight behavior (how does the model change when different design changes are made) and then iterate.
