Using a pair of antagonistic Shape Memory Allow (SMA) wires, it may be possible to produce a mechanism that replicates human musculoskeletal movement. The movement of interest is the articulation of the elbow joint actuated by the biceps brachii muscle. In an effort to understand the bio-mechanics of the arm, a single degree of freedom crankslider mechanism is used to model the movement of the arm induced by the biceps brachii muscle. First, a purely kinematical analysis is performed on a rigid body crank-slider. Force analysis is also done modeling the muscle as a simple linear spring. Torque, rocking angle, and energy are calculated for a range of crank-slider geometries. The SMA wire characteristics are experimentally determined for the martensite detwinned and full austenite phases. Using the experimental data, an idealized actuator characteristic curve is produced for the SMA wire. Kinematic and force analyses are performed on the nonlinear wire characteristic curve and a linearized wire curve; both cases are applied to the crankslider mechanism. Performance metrics for both cases are compared, followed by discussion.
KEYWORDS: Actuators, Aerodynamics, Microsoft Foundation Class Library, Composites, Wind measurement, Control systems, Finite element methods, Chemical elements, Solid state physics, Smart structures
A type of piezoceramic composite actuator commonly known as Macro-Fiber-Composite (MFC) is used for actuation in
a variable camber airfoil design. The study focuses on aerodynamic and kinematical modeling, and static response
characterization under aerodynamic loads for three similar concepts. From a broader perspective, the study aims to
understand the behavior of solid-state aerodynamic vectoring in high dynamic pressure air flow. Wind tunnel
experiments and theoretical analysis is conducted on a 1.15% thick, 54 mm chord, and 108 mm span composite airfoil.
The airfoil is fabricated from a fiberglass/epoxy composite material and actuated by six MFC actuators in a unimorph
arrangement. Three support concepts are studied: 1) Airfoil hinged at its leading edge and at 50% chord; 2) Airfoil
hinged at its leading edge the trailing edge; 3) Clamped-free airfoil. Wind tunnel results and XFOIL studies of the airfoil
show comparable effectiveness to conventional actuation systems. Deformation of the airfoils due to pressure
distribution is studied by finite element method. All concepts present adequate stiffness for flow speeds up to 30 m/s.
Conventional control surfaces have been used in most carbon fiber composite, membrane-wing autonomous
micro air vehicles (MAV). In some cases, vehicle morphing is achieved using servo actuators to articulate vehicle
kinematic joints, or to deform crucial wing / tail surfaces. However, articulated lifting surfaces and articulated
wing sections are difficult to instrument and fabricate in a repeatable fashion. Assembly is complex and time
consuming. The goal of this paper is to establish the feasibility of morphing wings on autonomous MAVs that
are actuated via active materials. Active actuation is achieved via a type of piezoceramic composite called Macro
Fiber Composite (MFC). This paper investigates the structural dynamics of morphing wings on MAVs that are
actuated via active composites. This paper continues the work presented in1 by considering structural dynamic
characteristics of the morphing vehicle determined through Scanning Laser Doppler Vibrometry (SLDV).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.