1. Simplify the above system block diagram, and determine its closed-loop transfer functions.
(Hint: shift and join summing junction 2 and 3)
For the following questions, given G(s)H (s) = (100K/((s + 10)(s + 15)(s + 30))) x1
2. Determine the range of K that will make this unity feedback system stable using Routh-Hurwitz criterion.
3. Given K=90, draw the Bode plots for the above system, and determine its gain margin and phase margin.
4. Obtain the steady-state error for a unit step input.
5. If you are required to improve its transient response, will you choose a PI, a PD, a PID, a phase lead, a phase lag or a phase-lead-lag controller?