P9.15 Consider the automatic ship-steering system trans

fer function.

G(s) = -0.164(s+ 0.2)(s-0.32) s2 (s+ 0.25)(s-0.009) 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 &(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(s)? (c) Is it possible to stabilize this system with a deriva- tive feedback controller? (d) Suggest a suitable feedback controller. (e) Repeat part (a), (b), and (c) when switch S is closed.