Advanced 1.5 Hz Passive Viscous Isolation System

Presented at the AIAA 35th SDM Conference Hilton Head, South Carolina April 1994 Copyright „ 1994 by Honeywell Inc. A high-performance isolator has been developed for a multiaxis isolation system for a large reaction wheel assembly. Reaction wheel assemblies are used for spacecraft attitude control. The isolator offers significant improvements over prior isolators, providing a low break frequency and featuring a tuned, three-parameter configuration that significantly outperforms the more conventional two-parameter design. A three-parameter system is one that is modeled with spring elements in series and parallel with the damper. Two-parameter systems, as modeled in most vibration texts, have a single spring element in parallel with the damper. The system is tuned by selecting three-parameter values that provide maximum damping at the fundamental frequency and reduced damping at higher frequencies. The mathematical basis for three-parameter isolators with tuning methodology is included. Physical design features of the isolator are described in addition to actual test data that confirms the fundamental performance improvement. The technique for obtaining low suspension frequencies is also discussed.