Resources Contact Us Home
Methods for controlling spacecraft attitudes without exciting spacecraft resonances

Image Number 6 for United States Patent #6076772.

Attitude-control methods are provided which eliminate or reduce structural resonances in spacecraft that are excited by momentum wheel imperfections. The methods are preferably practiced with an over-determined attitude-control system which is typically available because spacecraft often carry backup momentum wheels to insure against failure of primary momentum wheels. In a method embodiment, a set of angular-velocity waveforms is selected that substantially realizes a commanded momentum vector when applied to a corresponding set of momentum wheels wherein none of the selected angular-velocity waveforms dwells at a resonant frequency of the spacecraft. The angular velocity of the corresponding set of momentum wheels is then conformed to the selected set of angular-velocity waveforms to realize a spacecraft attitude that corresponds to the commanded momentum vector without exciting the resonance. The step of selecting the angular-velocity waveforms can include the steps of offsetting a constant rotational frequency and of adding a velocity modulation to avoid dwelling at the resonant frequency.

  Recently Added Patents
Linked area parameter adjustment for spinal cord stimulation and associated systems and methods
Engineered enzymes with methionine-gamma-lyase enzymes and pharmacological preparations thereof
Restarting event and alert analysis after a shutdown in a distributed processing system
System and method for redundant array copy removal in a pointer-free language
Chair structure
Washing machine
Biomarkers of gastric cancer and use thereof
  Randomly Featured Patents
Film magazine
Mobile wireless medication management system
Apparatus and method for maintaining forwarding information in a bridge or router using multiple free queues having associated free space sizes
Strain gauge assemblies
Laser welding method
Broadband wireless system and network architecture providing broadband/narrowband service with optimal static and dynamic bandwidth/channel allocation
Bradykinin type peptides
Frictional holding pad
Medical terminal clip member for attachment to patient electrodes
Window latch