Consider the fluid temperature control of a parabolic trough collector (Camocho, 2012) embedded in the unity feedback structure as shown in Figure P8.3, where the open-loop plant transfer function is given by
Approximating the time-delay term with
make a sketch of the resulting root locus. Mark where appropriate in the plot and find:
a. The asymptotes and their intersection with the real axis;
b. The break-in and breakaway points.
c. The range of K for closed-loop stability;
d. The value of K that will make the system oscillate and the oscillation frequency.