초록 ▼

A control system (40) and procedure (50) that uses repetitive control to control repetitive error sources such as result from the phenomenon of thermal shock experienced by a spacecraft (10). Repetitive control is a “learning algorithm”that substantially eliminates errors in a stable control system

A control system (40) and procedure (50) that uses repetitive control to control repetitive error sources such as result from the phenomenon of thermal shock experienced by a spacecraft (10). Repetitive control is a “learning algorithm”that substantially eliminates errors in a stable control system (43) that performs highly repeatable tasks. The repetitive control system (40) and procedure (50) employs a repetitive signal generator (41) (Gr), to store a sensed short-term error signal during each cycle and to process it to generate a signal that compensates for the error. The repetitive control system and procedure integrates (52) the error signal over several cycles, multiplies (53) the integrated value by a predetermined gain factor, and sums (54) it with the sensed error signal before the sensed error reaches the stable controller (43). An output filter (42), Gf, which may be a multirate-sampling output filter, may be used to increase stability robustness of the repetitive control system (40) and procedure (50). The present repetitive control system (40) and procedure (50) substantially eliminates pointing error caused by thermal shock disturbance, for example. The repetitive control system (40) and procedure (50) “learns”the errors that exist in the system and over several cycles, converges on a substantially exact compensation for these errors. Implementation of the present control system (40) and procedure (50) allows the spacecraft (10) to maintain precise pointing throughout an eclipse and thereby allow the spacecraft (10) to perform its mission despite the presence of thermal shock disturbances or errors caused by other repetitive error sources.

대표청구항 ▼

A repetitive control system for use within an attitude control system of a spacecraft that experiences a pointing error due to thermal shock disturbance, wherein the attitude control system comprises a computer that performs attitude control functions for the spacecraft, wherein the computer compris

A repetitive control system for use within an attitude control system of a spacecraft that experiences a pointing error due to thermal shock disturbance, wherein the attitude control system comprises a computer that performs attitude control functions for the spacecraft, wherein the computer comprises a stable controller (Gc) that communicates with spacecraft attitude control dynamics, wherein the repetitive control system comprises: a repetitive signal generator (Gr) for storing a short-term pointing error signal during each thermal shock disturbance cycle that is indicative of the pointing error of the spacecraft, for integrating the short-term pointing error signal over several cycles to provide an integrated pointing error signal, and for multiplying the integrated pointing error signal by a predetermined gain factor to provide an integrated and multiplied pointing error signal; and a summing device for summing the integrated and multiplied pointing error signal with the short-term pointing error signal and for providing the stable controller (Gc) with a compensated pointing error signal which compensates for spacecraft pointing error.