Proceedings Article | 11 April 2007
KEYWORDS: Actuators, Sensors, Vibration isolation, Signal attenuation, Electronics, Optical isolators, Feedback control, Satellites, Control systems, System identification
Precision satellite payloads commonly require isolation from bus disturbance sources, such as reaction wheels, thrusters,
stepper motors, cryo-coolers, solar array drives, thermal popping, and other moving devices. Since nearly every satellite
essentially has a unique construction, custom isolation systems are usually designed to attenuate a wide bandwidth of
disturbance frequencies. The disadvantage of these custom solutions is that they are not easily reusable or transferable
and are generally not robust to changes in payload geometry and mass properties during the development. The MVIS-II
isolation system is designed to provide vibration disturbance attenuation over a wide bandwidth, as well as being able to
adapt to changes in payload mass properties and geometry, through active control of a smart material.
MVIS-II is a collaborative effort between the Air Force Research Laboratory (AFRL) Space Vehicle Directorate and
Honeywell Defense and Space to validate miniature hybrid (passive/active) vibration isolation of sensitive optical
payloads. The original flight experiment was intended to isolate a non-critical representative payload mass for
demonstration purposes; however, the MVIS-II has been adapted to support the primary optical payload onboard the
Tactical Satellite 2 (TacSat-2). Throughout the program MVIS-II has been able to adapt to changes in the payload
geometry and mass properties with modification limited to support structures only.
The MVIS-II system consists of a hexapod of hybrid struts, where each strut includes a patented passive 3-parameter DStrut
n series with a novel hydraulically amplified piezoelectric actuator with integral load cell. Additionally,
Honeywell's Flexible I/O controller electronics and software are used for command and control of the hardware. The
passive D-Strut element provides a 40 dB/decade passive roll-off to attenuate mid-to-high frequency disturbances, while
the active piezoelectric actuator is used for enhanced low frequency isolation. MVIS-II struts are 90% smaller in size
and have 91% less mass than previous struts including Honeywell's Vibration Isolation, Suppression, and Steering
(VISS). The MVIS-II system is currently integrated in the TacSat-2, which has successfully launched from Wallops
Flight Facility on Wallops Island, Virginia in December 2006. MVIS-II was launched under direction of the DoD Space
Test Program.
This paper will discuss the adaptive design of the MVIS-II isolation system including simulation, testing, and
integration. Active and passive strut test results will be presented that demonstrate the wide bandwidth attenuation of
vibration disturbances. Simulation results of expected on-orbit performance will also be discussed.
