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Youhanaie, Mark 2014-12-15T21:41:19Z 2014-12-15T21:41:19Z 10000-01-01 1984 1984 Motivated by economic and safety considerations, the ship propulsion and steering control problems are considered for the SL-7 containership. Extending previous work by Reid in the area of minimum-added-resistance steering control, modern multivariable control methods are applied to the steady-state coursekeeping control problem. Specifically, the full loop-transfer recovery procedure of Doyle and Stein is applied to provide acceptable stability margins at the plant input. Also, using robustness analysis and a numerically determined uncertainty bound, it is shown that the maximum allowable uncertainty in the ship hydrodynamic coefficients before a potential for closed loop instability exists is 6.5 percent. The multivariable propulsion/steering control problem is considered including the effect of a varying wake fraction. A new minimum mean fuel rate performance index is derived, but little improvement in propulsion economy is achieved compared to minimum-added-resistance steering control, as the steering induced losses constitute over 95 percent of the increased mean fuel rate. Analysis of multivariable stability margins reveals, however, very small stability margins when a decoupled control approach is used in the presence of the varying wake fraction. The benefit of employing the multivariable controller is therefore, that acceptable multivariable stability margins are achieved. Made available in DSpace on 2014-12-15T21:41:19Z (GMT). No. of bitstreams: 1 8502352.pdf: 5962782 bytes, checksum: 40b2411d65c96c983aeabe20785ff443 (MD5) Previous issue date: 1984 Embargo set by: Seth Robbins for item 70294 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 294 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984. http://hdl.handle.net/2142/70128 (UMI)AAI8502352 Engineering, Mechanical Application of Multivariable Control Theory to Improve Steering and Propulsion Control of a Containership text Mechanical Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.