Due to the availability of small sensors, Micro-Aerial Vehicles (MAVs) can be used for detection missions of biological,
chemical and nuclear agents. Traditionally these devices used fixed or rotary wings, actuated with electric DC motortransmission,
a system which brings the disadvantage of a heavier platform. The overall objective of the BATMAV
project is to develop a biologically inspired bat-like MAV with flexible and foldable wings for flapping flight. This
paper presents a flight platform that features bat-inspired wings which are able to actively fold their elbow joints. A
previous analysis of the flight physics for small birds, bats and large insects, revealed that the mammalian flight anatomy
represents a suitable flight platform that can be actuated efficiently using Shape Memory Alloy (SMA) artificial-muscles.
A previous study of the flight styles in bats based on the data collected by Norberg [1] helped to identify the required
joint angles as relevant degrees of freedom for wing actuation. Using the engineering theory of robotic manipulators,
engineering kinematic models of wings with 2 and 3-DOFs were designed to mimic the wing trajectories of the natural
flier Plecotus auritus. Solid models of the bat-like skeleton were designed based on the linear and angular dimensions
resulted from the kinematic models. This structure of the flight platform was fabricated using rapid prototyping technologies and assembled to form a desktop prototype with 2-DOFs wings. Preliminary flapping test showed suitable trajectories for wrist and wingtip that mimic the flapping cycle of the natural flyer.
This paper presents an actuator placement study for a bio-inspired joint that is part of a smart-materials-based bat wing.
The wing has been designed as part of the BATMAV project with the final goal of developing a biologically-inspired
micro-air vehicle with foldable wings for flapping flight. The wing uses superelastic Shape Memory Alloy (SMA) joints
and SMA muscle wire actuation. A kinematic model for the bat's flapping flight motion has been developed in a
previous paper, while the current paper presents a study to determine attachment points for SMA actuator wires. At the
center of the current analysis is the requirement to maintain compatibility with a typical SMA's strain capabilities while
simultaneously ensuring the required joint angle motion to be achieved. The study yields a range of attachment
parameters, which result in contraction strains of up to 2.5%, appropriate for high-cycle actuation.
The overall objective of the BATMAV project is the development of a biologically inspired bat-like Micro-Aerial
Vehicle (MAV) with flexible and foldable wings, capable of flapping flight. This first phase of the project focuses
particularly on the kinematical analysis of the wing motion in order to build an artificial-muscle-driven actuation system
in the future. While flapping flight in MAV has been previously studied and a number of models were realized using
light-weight nature-inspired rigid wings, this paper presents a first model for a platform that features bat-inspired wings
with a number of flexible joints which allows mimicking the kinematics of the real flyer. The bat was chosen after an
extensive analysis of the flight physics of small birds, bats and large insects characterized by superior gust rejection and
obstacle avoidance. Typical engineering parameters such as wing loading, wing beat frequency etc. were studied and it
was concluded that bats are a suitable platform that can be actuated efficiently using artificial muscles. Also, due to their
wing camber variation, they can operate effectively at a large range of speeds and allow remarkably maneuverable flight.
In order to understand how to implement the artificial muscles on a bat-like platform, the analysis was followed by a
study of bat flight kinematics. Due to their obvious complexity, only a limited number of degrees of freedom (DOF)
were selected to characterize the flexible wing's stroke pattern. An extended analysis of flight styles in bats based on the
data collected by Norberg and the engineering theory of robotic manipulators resulted in a 2 and 4-DOF models which
managed to mimic the wingbeat cycle of the natural flyer. The results of the kinematical model can be used to optimize
the lengths and the attachment locations of the wires such that enough lift, thrust and wing stroke are obtained.
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