The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 11, 2003
Filed:
Sep. 13, 2000
Thomas J. Holmes, Portola Valley, CA (US);
Space Systems/Loral, Inc., Palo Alto, CA (US);
Abstract
A spacecraft attitude control system that enables friction and stiction compensation for attitude control of a spacecraft using at least one reaction wheels that can spin through zero rpm without degradation in pointing. The system removes nuisance disturbances relating to friction or stiction that detract from the ability of the system to maintain or change spacecraft attitude. It can remove these effects before they are sensed by the systems attitude control sensors. A friction or stiction compensation buffer is arranged between the spacecraft attitude control subsystem and the torque actuators for the at least one reaction wheel. Since the compensation is localized to each wheel, it is possible to optionally: control wheel operating speeds to safe levels, provide wheel failure flags, provide accurate wheel tracking at slow or zero wheel speeds and provide full access to the wheel torques.