Title: Automatic Control
1Automatic Control
Review
2Feedback Terminology
In Block diagrams, we use not the time domain
variables, but their Laplace Transforms. Always
denote Transforms by (s)!
3State-Variable Form
- Deriving differential equations in state-variable
form consists of writing them as a vector
equation as follows
where is the
output and u
is the input
4Transfer Function
5The transfer function of the system shown is
MEG 421 Chapter 3
5
6The transfer function of the system shown is
The stability of the closed loop is determined by
- (A) G1 alone
- (B) closed loop Num. and Denom.
- (C) closed loop Denom. alone
- (D) Gain K alone
- (E) The product KG1(s)
7The transfer function of the system shown is
The stability of the closed loop is determined by
- (A) G1 alone
- (B) closed loop Num. and Denom.
- (C) closed loop Denom. alone
- (D) Gain K alone
- (E) The product KG1(s)
8The Steady-state error ess of the closed loop to
a unit step R(s) 1/s is
- (A) ess 1/K
- (B) ess 1
- (C) ess 0
- (D) ess ?
9The Steady-state error ess of the closed loop to
a unit step R(s) 1/s is
- (A) ess 1/K
- (B) ess 1
- (C) ess 0
- (D) ess ?
10For tracking control (following a ramp reference)
the minimum number of integrators in the control
loop is
- (A) n 0
- (B) n 1
- (C) n 2
- (D) the number of integrators is not relevant.
11For tracking control (following a ramp reference)
the minimum number of integrators in the control
loop is
- (A) n 0
- (B) n 1
- (C) n 2
- (D) the number of integrators is not relevant.
12 The Root Locus Branches of the system shown
originate for K 0 at
- (A) s0, -1, -1
- (B) s0, -1/2, -1
- (C) s0, -2, -1
- (D) s0, -1
- (E) s0, 0.5, 1
13 The Root Locus Branches of the system shown
originate for K 0 at
- (A) s0, -1, -1
- (B) s0, -1/2, -1
- (C) s0, -2, -1
- (D) s0, -1
- (E) s0, 0.5, 1
14 The Root Locus branches of the system shown
terminate for K ? infinity at
- (A) closed-loop poles
- (B) zero
- (C) infinity
- (D) Two branches terminate at infinity, one at
zero - (E) One branch terminates at infinity, two at zero
15 The Root Locus branches of the system shown
terminate for K ? infinity at
- (A) closed-loop poles
- (B) zero
- (C) infinity
- (D) Two branches terminate at infinity, one at
zero - (E) One branch terminates at infinity, two at zero
16The Root Locus exists on the real axis between
- (A) infgtxgt0 and 0gtxgt-2 and -3gtxgt-4
- (B) -1gtxgt-2 and -3gtxgt-4
- (C) 0gtxgt-2 and -3gtxgt-4
- (D) 0gtxgt-1 and -3gtxgt-4 and -4gtxgt-inf
- (E) 0gtxgt-1 and -3gtxgt-4
17The Root Locus exists on the real axis between
- (A) infgtxgt0 and 0gtxgt-2 and -3gtxgt-4
- (B) -1gtxgt-2 and -3gtxgt-4
- (C) 0gtxgt-2 and -3gtxgt-4
- (D) 0gtxgt-1 and -3gtxgt-4 and -4gtxgt-inf
- (E) 0gtxgt-1 and -3gtxgt-4
18The RLocus of an unstable system with transfer
function is shown at left. We can stabilize
the closed loop by
X
X
X
- (A) adding poles on the negative real axis
- (B) adding a lead element on the negative real
axis, with the zero between 0 and -4 - (C) adding a lead element on the negative real
axis, with the zero to the left of -4 - (D) adding a lag element on the negative real
axis, with the pole close to the origin. - (E) the closed loop cannot be stabilized
19The RLocus of an unstable system with transfer
function is shown at left. We can stabilize
the closed loop by
X
X
X
- (A) adding poles on the negative real axis
- (B) adding a lead element on the negative real
axis, with the zero between 0 and -4 - (C) adding a lead element on the negative real
axis, with the zero to the left of -4 - (D) adding a lag element on the negative real
axis, with the pole close to the origin. - (E) the closed loop cannot be stabilized
20The open-loop TF of the Root Locus plot shown at
left is
- (A)
- (B)
- (E) none of the above
21The open-loop TF of the Root Locus plot shown at
left is
- (A)
- (B)
- (E) none of the above
22For the given set of open loop poles and zeros,
the correct root locus is
- (C) Neither (A) nor (B) are correct
23For the given set of open loop poles and zeros,
the correct root locus is
- (C) Neither (A) nor (B) are correct