Active Vibration Control Of Flexible Spacecraft During Attitude Maneuver

Active vibration control technique is the key technology of designing of attitude control system for large flexible spacecraft to fulfill mission requirements such as precision pointing and integrity of structures. Based on the requirements of high precision pointing/targeting of advanced spacecraft, dynamic modeling of spacecraft with flexible appendages bonded with piezoelectric sensors/actuators, attitude control and active vibration suppression theory are studied deeply in this dissertation, which is funded by the Research Fund for the Doctoral Program of Higher Education of China Item—"Large flexible multi-bodies structure spacecraft active vibration control technology"(20050213010). The main contents of this dissertation are as the follows:An approximate analytical dynamic model of a flexible spacecraft with surface bonded piezoelectric sensors and actuators is derived using Hamilton's principle with discretization by the assumed mode method. The model is then converted to state-space form for the purpose of control design. In addition, the principle of Component Synthesis Vibration Suppressing (CSVS) method is also briefly introduced and summarized to several lemmas, which can suppress flexible vibration by utilizing the character of vibration system itself and has the characters of simple, multiform, easy to apply and so on. All these are the foundation of the latter control system design and the software developed.A hybrid control scheme of CSVS method and the technology of active vibration suppression using piezoelectric materials is proposed for the vibration control of a flexible spacecraft actuated by on-off thrusters. The proposed control system includes the attitude controller acting on the rigid hub, designed by using pulse-width pulse-frequency (PWPF) modulation integrated with command shaping technique based on CSVS method, and the piezoelectric material elements as sensors/actuators bonded on the surface of the beam appendages, designed by the optimal positive position feedback (OPPF) control technique, in which the selection of PPF gains is determined via introducing a cost function to be minimized by feedback gains which are subject to the stability criterion at the...