Title page for ETD etd-02012006-141752
|Type of Document
||Ellis, Graham K.
||H[infinity] and LQG optimal control for the rejection of persistent disturbances : analysis, design and experiment
|Robertshaw, Harry H.
|Baumann, William T.
|Leonard, Robert G.
|Russell, David L.
|Wicks, Alfred L.
|Date of Defense
This dissertation presents a discussion of the asymptotic behavior and estimation
structure of the H∞ central controllers in terms of the well-known behavior of the
LQG controller and gives some insight into the physics of the H ∞ controller that
is often presented in an unclear manner in the current literature. The connections
to LQ game theory that underlie this confusion are discussed. Augmented systems
that are typically used in disturbance rejection problems are also analyzed. Additionally,
a controlled output equation for disturbance rejection is developed based
on the physics of the problem rather than the typical ad hoc approaches of the
past. These controlled output equations are also appropriate for LQG compensators.
In order to verify the proposed approach, an experiment in harmonic and
narrowband disturbance rejection using a simply supported steel plate is presented.
Discrete-time LQG, and continuous-time H∞ and LQG controllers that have been
transformed to discrete-time are used to determine the attainable performance of
each approach. The results indicate that the H ∞ controller provides more damping
than either LQG approach and that discrete-time design procedures are necessary
for maximum disturbance rejection.
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