KEYWORDS: Actuators, Shape memory alloys, Thermoelectric materials, Transmission electron microscopy, Control systems, Temperature metrology, Sensors, System identification, Convection, Control systems design
Development and test results of a rotor blade twist control system that utilizes a thermo-mechanical shape memory alloy
(SMA) are presented. The actuation system controls the blade shape during flight operations allowing the blade to be
configured for greater lift during takeoff and landing. SMA actuators provided an excellent solution because of their
very high torque output to weight ratio and suitability to the dynamic environment of a rotor blade. Several challenges
related to the behavior of the SMA material are overcome by innovative control system design. Thermoelectric
modules (TEM's) are used to actively transfer heat between SMA tubes and other heat conductor and radiator
components. Modeling and system identification techniques and a non-trivial solution to nonlinear and coupled
thermal response equations are used to insure effective use of the TEM's and to improve control during SMA phase
transition.
KEYWORDS: Head, Fluctuations and noise, Prototyping, Space operations, Actuators, Interfaces, Control systems, Sensors, Motion measurement, Data modeling
Space flight experiment test results of a Space Station Active Rack Isolation System (ARIS) are presented. The purpose of ARIS is to isolate microgravity sensitive science experiments mounted in Space Station racks from structural vibrations present on the large Space Station orbital structure. The overall objectives of the experiment were 1) to test and evaluate the ARIS design modifications made from 1997 to 2000 as a result of prototype flight testing performed on the Space Shuttle Atlantis, 2) to characterize isolation performance on the International Space Station, 3) to assess the impact that rack payload disturbances have on the microgravity environment, 4) to test alternative umbilicals designed to improve isolation performance, and 5) to gain on-orbit operational experience and validate procedures. The scope of the material presented is limited to microgravity performance issues, so only results related to the first four objectives are presented. Over a year of flight testing was completed, and ARIS consistently has performed extremely well such that station vibrations were isolated to levels well below the science requirement.
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.