Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
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
Noise suppression in speech signals
Liquid crystal display panel
Shape memory polymers formed by self-crosslinking of copolymers
Methods and systems for temporarily sharing position data between mobile-device users
Device for accurately measuring concentration of component in blood and control method of the device
Method of synchronization for low power idle
Device and method for unified codes
  Randomly Featured Patents
Vent disc with center knob
Prefabricated bow forming machine
Semiconductor device package
Image sensor with expanding dynamic range
Microwave rotatable sputtering deposition
System and method of controlling application level access of a subscriber to a network
One way screwdriver
Generating a parallel recovery plan for a data storage system
PRO5993 polypeptides
Personal safety device