Stability analysis of a non-minimum phase Electro-Hydraulic Servo System (EHSS) and identification of parametric uncertainty
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Date
2021-12Publisher
Brac UniversityAuthor
Ahmed, Mazid IshtiqueMetadata
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The electro-hydraulic servo system (EHSS) is a common tool in a variety of modern-day
industrial applications that mostly deal with aviation and vehicle manufacturing and operation.
In this thesis, an electro-hydraulic servo system is presented which bears the characteristics of
non-minimum phase (NMP) phenomenon. A discrete-time transfer function for investigating
the EHSS-NMP features has been estimated using a revamped mathematical model of the
EHSS with respect to existing model parameters. An optimal control strategy is then
formulated based on discrete linear quadratic regulator (DLQR) that seemingly, optimizes the
control issues associated with EHSS affected by NMP behavior. A comparative analysis shows
that the EHSS stability response improves with the DLQR, but the NMP behavior still persists.
This thesis also tries to identify parametric uncertainties through a comprehensive
mathematical model of EHSS. The modeling constraints are then investigated to propose a
finite frequency robust control technique to actuate an active suspension load subjected to road
disturbances. Using various performance criteria, simulation results are able to determine an
optimum trade-off between robust control and rejecting road disturbances at higher deflection
frequencies. As a result, these studies have demonstrated that the proposed control technique
may overcome the parametric uncertainties of an EHSS-driven active suspension load.