Flashcards
Ship Control and Manoeuvring
Cards in this deck (33)
- 1What is the definition of a transfer function?The transfer function of a (sub)system is the ratio of the Laplace transforms of its output and input, assuming zero
initial conditions - 2What are the properties of systems whose responses can be described as transfer functions?Linear
Time Invariant - 3State the final value theorem
- 4What is the most common use of the final value theorem in control system design?Allows the steady state or final value of f(t) to be found
- 5Given a 2nd order transfer function with damping ratio and natural frequency, what is the estimate of the step response? What is the estimate of settling time?
- 6What is the major effect of an extra zero in the left half-plane on the 2nd order step response?A zero pulls the loci towards it and causes a larger overshoot
- 7What is the main effect of an extra real pole on the second order step response?The pole pushed the loci away from it
The range of K reduces
Generally lowers stability
Settling time increases - 8Why is stability an important consideration in control system design?h
- 9What is the main use of Routh's criterion?To determine the stability of a system
- 10What is the main objective of introducing integral control?Give an output which is proportional to the integral of the error signal
- 11What is the main objective of introducing derivative control?Attempts to anticipate future error values from the rate of change of the error signal.
- 12Why might a designer wish to put the derivative term in the feedback rather than the error path?An derivative control tends to amplify noise.
- 13State the units of Kp, Kv and Ka.a
- 14What is the definition of system type with respect to reference inputs?s^-2, s^-1, s^-2
- 15What is the definition of system type with respect to disturbance inputs?a
- 16Why does system type depend on where the external signal enters the system.a
- 17Give reasons for the use of a digital controller rather than a analogue controller.a
- 18Give two disadvantages to using a digital controller.a
- 19What is the effect of adding an extra pole to the forward path in a feedback system?a
- 20Give a definition for the root locus.a
- 21What is the dominant pole in a second order system?a
- 22What is the principle intention of lead compensation on a root locus?a
- 23Why is velocity feedback often used in position controls?a
- 24Why is system linearization often known as small-signal approximation?a
- 25Why is positive feedback destabilising?a
- 26What is the Routh-Hurwitz criterion?a
- 27Write the input-output relationship of a PID controller in the time domain and determine the corresponding transfer function.a
- 28Explain the concept of a slow motion derivativeYv represents the change in sway force due to change in sway velocity whilst all other variables are set in the steady reference motion.
- 29What does the term Y(t) denote?Additional fluid forces due to waves, current, control surfaces etc.
- 30What do X, Z, M, Y, K, N represent?X: Surge
Z: Heave
M: Pitch
Y: Sway
K: Roll
N: Yaw - 31What do the subscripts v, p, r, w, u, q and theta, phi represent?v: Sway Velocity
w: Heave Velocity
u: Surge Velocity
p: Roll Angular Velocity
r: Yaw Angular Velocity
q: Pitch Angular Velocity
theta: Pitch angle
phi: Roll angle - 32For a stable ferry in a steady turn discuss the signs of the constants E and C.0
- 33What is the estimate of settling time?
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- Flashcards on Ship Control and Manoeuvring, created by tom8390 on 12/05/2015.
- Created by
- tom8390 · May 2015
- Updated
- Jul 19, 2016
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