The effects of shipboard steering machinery dynamics on rudder roll stabilization systems.

40 Pages·0.46 MB·en_US

by  Wendel, Michael W.;Schmidt, Louis V.

NAVAL POSTGRADUATE SCHOOL
Monterey
California
,
THESIS
THE EFFECTS OF SHIPBOARD STEERING
MACHINERY DYNAMICS ON RUDDER
ROLL STABILIZATION SYSTEMS
by
Michael \V. Wcndcl
September 1991
Thesis Advisor Louis V. Schmidt
1259272
Approved for public release; distribution is unlimited.

L'nclassified
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REPORT DOCUMENTATION PACT.
la Report Security Classification Unclassified lb Restrictive Markings
2a Sccuntv Classification Authority 3 Distribution Availability of Report
b Declassification Downcradins Schedule Approved for public release; distribution is unlimited
i Pcrfi rrr.in? Organization Report Numbej(s) 5 Monitonns Organization Report Number!s^
6a Name of Performing Organization 6b Olfice Symbol 7a Name of Monitoring Organization
Naval Postgraduate School (ifapplicable) 34 Naval Postgraduate School
6c Address (cir,\ state, and ZIP code) 7b Address (citv, state, and ZIPcode)
Monterev, CA 93943-5000 Monterey, CA 93943-5000
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(ifapplicable)
Sc Address (city, state, and ZIP code) 10 Source of Funding Numbers
Program Element No Proieci No Task No Work L'nit Accession No
u Title (includesecure classification) THE EFFECTS OP SHIPBOARD STEERING MACHINERY DYNAMICS ON
REDDER ROLL STABILIZATION SYSTEMS
12 Personal Author(s) Michael YV. Wendel
13a 1 ype of Report 13b Time Covered 14 Date of Report (year, month, day) 15 Page Count
Master's Thesis From To September 1991 31
16 Supplementary Notation The views expressed in tliis thesis arc those of the author and do not reflect the official policy or po-
sition of the Department of Defense or the U.S. Government.
Cos.r.i Codes 18 Subject Terms (continue on reverse Ifnecessary andIdentify by block number)
Field Group Subgroup rudder roll stabilization
19 Abstract (continue on reverse ifnecessary andidentify by block number)
The surface ship rolling motion equation is modeled as a second order system, with a natural frequency of a>n = 0.4/ sec
and a dimensionless damping ratio of£ = 0.08. The model is subjected to a random forcing function, winch has a Gaussian
probability distribution and can be considered as "wlute noise", and placed into State-Space form. State variable feedback of
roll rate is applied and the system discrctized to match digital control. Roll angle time histories are developed for a range of
feedback gains and compared. Additionally, steering machinery dynamics are modeled by a first order system and time con-
stants varied to determine the effects ofrudder dynamics on the feedback system.
20 Distribution/Availability ofAbstract 21 Abstract Security Classification
E D
unclassified/unlimited same as report DTIC users Unclassified
22a Name of Responsible Individual 22bTelephone (includeArea code) 22c Office Symbol
Louis V. Schmidt [phone] 54SS
3D FORM 1473,84 MAR 83 APR edition may be used until exhausted security classification ofthis page
All other editions are obsolete
Unclassified
Approved for public release; distribution is unlimited.
The Effects of Shipboard Steering
Machinery Dynamics on Rudder
Roll Stabilization Systems
by
Michael W. Wcndcl
Lieutenant, United States Navy
B.S., Villanova University, 19S4
Submitted in partial fulfillment of the
requirements for the degree of
MASTER OF SCIENCE IN MECHANICAL ENGINEERING
from the
NAVAL POSTGRADUATE SCHOOL
September 1991
J J //
• * . .
7f "
Anthony J. Hca/fpy, Chairman,
Department of Mechanical Engineering
ABSTRACT
The surface ship rolling motion equation is modeled as a second order system, with
a natural frequency of con — 0.4/.sec and a dimcnsionless damping ratio of £ = 0.08. The
model is subjected to a random forcing function, which has a Gaussian probability dis-
tribution and can be considered as "white noise", and placed into State-Space form. State
variable feedback ofroll rate is applied and the system discretized to match digital con-
trol. Roll angle time histories are developed for a range offeedback gains and compared.
Additionally, steering machinery dynamics are modeled by a first order system and time
constants varied to determine the effects ofrudder dynamics on the feedback system.
VI
TABLE OF CONTENTS
INTRODUCTION
I. 1
VESSEL DYNAMIC MODELING
II. 3
A. MODEL OF VESSEL DYNAMICS 3
STATE-SPACE EQUATION
B. 5
DISCRETIZATION
C. 5
FEEDBACK
D. 6
RUDDER CONTROL MODEL
E. 7
THE COMPLETE SYSTEM
F. 9
RESULTS
III. 10
A. FEEDBACK EFFECTS 11
STEERING SYSTEM EFFECTS
B. 13
CONCLUSIONS AND COMMENTS
IV. 19
APPENDIX THE INVERSE PROBLEM 20
LIST OF REFERENCES 21
INITIAL DISTRIBUTION LIST 22
IV