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Problem 4.11 PP Consider the system shown in Fig., which represents control of the angle of a pendulum that has no damping. (a) What condition must Dc(s) satisfy so that the system can track a ramp reference input with constant steady-state error? (b) For a transfer function Dc(s) that stabilizes the system and satisfies the condition in part(a), find the class of disturbances w(t) that the system can reject with zero steady-state error. Figure Control system c Control Of Dynamic Systems (7th Edition) Problem Consider the system shown in Fig., which represents control of the angle of a pendulum that has no damping. (a) What condition must Dc(s) satisfy so that the system can track a ramp reference input with constant steady-state error? (b) For a transfer function Dc(s) that stabilizes the system and satisfies the condition in part(a), find the class of disturbances w(t) that the system can reject with zero steady-state error. Figure Control system j * + a: (1) step 2 of 6 The reduced block diagram is shown in Figure 1. w Step 3 of 6 From Figure 1, the closed loop transfer function is. Substitute — !— for r ( s ) in the above equation. A M _ ! _ W(s] step 4 of 6 Determine the expression for error signal. A M=*M- i ’ + A :+ o . ( j ) ' ' i '+ A : + z ) . ( j ) w ( , )