ASE 370L - Practice Test 3

# ASE 370L - Practice Test 3 - tions are zero 3(34pts A...

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Flight Control Systems Test #1 Dr. Bishop - Spring 2008 Closed-book; 75 minutes 1. (33pts) Consider the control system shown in Figure 1. (a) List two advantages of closed-loop feedback. List one disadvantage of closed-loop feedback. (b) Compute the tracking error E ( s ) = Y ( s ) - R ( s ). (c) Determine the closed-loop characteristic equation. (d) Find the ranges of K P , K D , K I and τ for closed-loop stability. (e) Determine values for K P , K D , and K I so that the steady-state track- ing error to a unit ramp disturbance T d ( s ) is less than 0.1 when τ = 1. + Y ( s ) - R ( s ) Process Controller E a ( s ) 1 s ( s + τ29 T d ( s ) K p + K I s + + + N ( s ) K D s + Figure 1: Block Diagram for Problem 1. 2. (33pts) Consider the system given by ¨ y + 5 ˙ y + 6 y = 6 u (1) (a) Determine a state variable model of the system in the Eq. (1) of the form ˙ x = Ax + B u y = Cx + D u Clearly de±ne the state variables. (b) Compute the characteristic equation of the system. (c) Compute the transfer function of the system. (d) Obtain the unit step response of the system when the initial condi-

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Unformatted text preview: tions are zero. 3. (34pts) A system has the closed-loop unit step response depicted in Figure 2. (a) What is the (minimum) system type number of the loop transfer function? Explain your answer. (b) Compute the dominant poles of the closed-loop system. (c) Do you think that the closed-loop system behaves exactly like a second-order system (no zeros and only two poles)? Why or why not? (d) Sketch the pole-zero map of the closed-loop system. Indicate on the pole-zero map how you would move the dominant poles if you needed a shorter settling time without changing the percent overshoot. Step Response Time (sec) Amplitude 1 2 3 4 5 6 0.2 0.4 0.6 0.8 1 1.2 1.4 System: sys Final Value: 1 System: sys Time (sec): 4.25 Amplitude: 1.02 System: sys Peak amplitude: 1.04 Overshoot (%): 4.32 At time (sec): 3.14 Figure 2: Unit step response for Problem 3....
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ASE 370L - Practice Test 3 - tions are zero 3(34pts A...

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