Title page for ETD etd-10132010-020121
|Type of Document
||Ide, Eric Nelson
||Evaluation of linear DC motor actuators for control of large space structures
||Master of Science
|Beex, A. A. Louis
|Bingular, Stanoje P.
|Lindner, Douglas K.
|Date of Defense
This thesis examines the use of a linear DC motor as a proof mass actuator for the
control of large space structures. A model for the actuator, including the current and
force compensation used, is derived. Because of the force compensation, the actuator
is unstable when placed on a structure. Relative position feedback is used for actuator
stabilization. This method of compensation couples the actuator to the mast in a feedback
configuration. Three compensator designs are proposed. The physical limits of the
LDCM place limits on the bandwidth of the closed loop actuator.
A ten mode finite element model of a flexible space structure was used in simulations
to examine all aspects of the actuator's performance. The performance of the
actuator is compared for the three compensator designs. The actuator bandwidth is seen
to be important in the actuator's effectiveness. Increasing actuator bandwidth resulted
in a saturation nonlinearity in the actuator. The excitation capability of the actuator
was examined to determine the authority of the actuator. The damping of the mast
modes was examined to determine the effect of the feedback configuration of the
actuator/mast system. Root locus techniques were used to explain changes in the
vibrational modes of the structure due to the actuator compensation. Disturbance
analysis was performed to quantify the effect of corrupted measurements on the purity
of force generated by the actuator.
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