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:
Oct. 31, 2000
Filed:
Jun. 11, 1999
Thomas J Holmes, Portola Valley, CA (US);
Space Systems/Loral, Inc., Palo Alto, CA (US);
Abstract
An automatic apparatus and method that is used to switch actuators, such as momentum wheels, used on a spacecraft without impacting the pointing performance of the spacecraft. The apparatus and method allows an actuator to be automatically deactivated without affecting spacecraft performance such as is caused by a failed actuator. A plurality of local actuator controllers are respectively coupled to a plurality of actuators. A system controller is coupled to the plurality of local controllers and implements a control algorithm corresponding to the present method that determines forces/torques for each of the actuators and outputs force/torque commands to each of the actuators to control the pointing direction of the spacecraft. This is achieved by estimating the drag exerted by or integral control signal produced by each actuator to determine if it is approaching failure. In the event of failure, a backup actuator is activated, the failing actuator is shut down, and the forces/torques exerted by the remaining actuators are adjusted in an amount corresponding to the force/torque exerted by the failing actuator.