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
Methods to fabricate a photoactive substrate suitable for microfabrication
Solid-state imaging device and method for manufacturing the same
Assisting apparatus, method, and program for checking crosstalk noise between hierarchized modules in a semiconductor circuit
Pre-colored methodology of multiple patterning
Media processing method and device
Stopper, motor, and disk drive apparatus
Magnetic reading and writing device
  Randomly Featured Patents
Reflective plate, liquid crystal display (LCD) using same, and electronic apparatus using this LCD
Device for collecting a blood sample from a plastic segment tube
Foot retaining device for inversion exerciser
Multi-level waveguide
Acid-soluble cement compositions comprising cement kiln dust and/or a natural pozzolan and methods of use
Moving shooting target system
Pneumatic tool
Method and apparatus for monitoring heart rate and abnormal respiration
Sorter
Method and device for non-invasive monitoring of hydration state of plants