Consider the automatic ship-steering system discussed in Problem P8.ll. The frequency response of the open-loop portion of the ship steering control system is shown in Figure P8.ll. The deviation of the tanker from the straight track is measured by radar and is used to generate the error signal, as shown in Figure P9.15. This error signal is used to control the rudder angle 8(s).
(a) Is this system stable? Discuss what an unstable ship-steering system indicates in terms of the transient response of the system. Recall that the system under consideration is a ship attempting to follow a straight track.
(b) Is it possible to stabilize this system by lowering the gain of the transfer function G(.v)?
(c) Is it possible to stabilize this system? Suggest a suitable feedback compensator.
(d) Repeat parts (a), (b), and (c) when switch S is closed.

FIGURE P9.15 Automatic ship steering.

Transcribed Image Text:

Desired constant heading Rudder angle 6(s) Ship + E(s) Heading Derivative feedback Ks Switeh S