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:
May. 10, 1994
Filed:
Jun. 10, 1993
John F Yocum, Rancho Palos Verdes, CA (US);
Dan Y Liu, Rancho Palos Verdes, CA (US);
Richard A Fowell, Culver City, CA (US);
Douglas J Bender, Redondo Beach, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
The three axes thruster modulation (8) of the present invention accepts three axes of input torque commands or angular acceleration commands and generates thruster selection and thruster timing (40) information which is used to fire thrusters (48) for the purpose of spacecraft attitude control and velocity change maneuvers. The modulation logic (8) works in all three axes simultaneously and is suitable for use with an arbitrary thruster configuration, including a configuration in which individual thrusters or thruster groups do not produce torques about mutually orthogonal axes. After thruster selection and on-times have been determined, the modulation logic (8) uses this information to compute a best estimate of the actual rate change (42) which is then compared to the commanded rate change (44) to develop a residual unfired rate change. The residual unfired rate change is retained and fed forward for addition to the subsequent acceleration command in computing the commanded rate change for the subsequent sample period (10, 20, 30). As a result, all commanded rate changes will ultimately be fired even if the commanded rate change is below a minimum rate change achievable.