作者newacc (XD)
看板NTU-Exam
標題[試題] 101上 王富正 自動控制
時間Thu Nov 1 15:54:33 2012
課程名稱︰自動控制
課程性質︰必修
課程教師︰王富正
開課學院:工學院
開課系所︰機械系
考試日期(年月日)︰101/10/30
考試時限(分鐘):180
是否需發放獎勵金:是
(如未明確表示,則不予發放)
試題 :
Automatic Control
1st Midterm Exam, 30/Oct/2012
1. (5%) Given f(t) = e^-at sin(ωt), derive its Laplace Transform L[f(t)].
(必須有推導過程)
2. (20%) Refer to Fig.2,
(1) (5%) Derive the two dynamic equations of the system.
(2) (5%) Find the transfer function of X(s)/U(s).
(3) (5%) Define the system state z = [ x xdot y ydot ]^T , find the
state-space model of the system.
(4) (5%) Draw the corresponding block diagram of the state-space
representation of (3).
┌─┤├─┐
│ C2 │
██████ ├─══─┤
︴ │ │┌┐R2 │
k1 ︴ ︴ ││└┐ │
M1 □ ︴k2 ●─══─┤├┴┤- └┐│
︱ ︴ R1 C1 │ ├┴───●
b1│┴│ ︴ V1 ┌┤+ ┌┘
└┬┘ │ ││┌┘ V2
┌┴──┴┐ │└┘
└─┬──┘M2 ●──────┼────────●
↓u(t) ┴
Fig.2 Fig.3
3. (15%) Refer to Fig.3,
(1) (5%) Find the transfer function T = V2(s)/V1(s).
(2) (5%) Find the sensitivity of T to R1, i.e., S(T)(R1).
(3) (5%) Suppose R1 = 1 kΩ, R2 = 2 kΩ, C1 = 1 mF, C2 = 0.1 mF,
find V2(t) to a step input V1(t) = 1, t ≧ 0
4. (20%) Consider a transfer function
G(s) = ( s - 2 ) / ( s^3 + 6s^2 + 11s + 6 ),
(1) (5%) Derive its controller canonical form, and draw the corresponding
block diagram.
(2) (5%) Derive its observer canonical form, and draw the corresponding
block diagram.
(3) (5%) Derive its Jordan form, and draw the corresponding block diagram.
(4) (5%) Find the state response of (3) the the initial state [ 1 -1 1 ]^T.
5. (20%) Consider the closed-loop system of Fig.5, with
G(s) = ( s + 1 ) / ( s^2 + 5s + 6 )
(1) (5%) Using a proportional (P) control K = Kp = constant, find the
steady-state error to a step input R.
(2) (5%) Using a proportional-integral (PI) control K = Kp + Ki/s,
where Kp, Ki are constant, find the steady-state error to a step
input R, and the steady-state error to a step disturbance Td.
(3) (5%) If the disturbance is a sinusoidal signal Td = sin(ωt), the output
response will be oscillatory with the above controllers. However,
we can eliminate the oscillation by putting the unstable mode at
the controller (it is so-called internal model principle) as
K = α / ( s^2 + ω^2 ), where α = constant. Find the steady-state
error to Td = sin(ωt).
(4) (5%) Design a controller such that (i) the steady-state error to a step
input R is zero; and (ii) the steady-state error to a sinusoidal
disturbance Td = sin(60t) is zero.
┌─────┐
│Controller│ Td(s)
+ ├─────┤ +↓
R(s) ─→○─→│ K ├─→○──┬→ Y(s)
-↑ └─────┘ + │
└──────────────┘
Fig.5
6. (20%) Consider the closed-loop system of Fig.5, with
G(s) = 1 / ( s^2 + 3s + 2 ) and a proportional-integral-derivative
(PID) control K = Kp + Ki/s + Kds, where Kp, Ki, Kd are constant.
(1) (5%) Find the sensitivity of the closed-loop system to Ki i.e., S(T)(Ki),
where T = T(R→Y).
(2) (5%) To make the steady-state error to a unit ramp input (R(t)=t,t≧0)
to be less than 0.1, find the minimal value of Ki.
(3) (5%) Set the desired closed-loop poles at s = -3, -4, -5, find the
required Kp,Ki,Kd values.
(4) (5%) Suppose Kp = 17 , Ki = 12 , Kd = 5 , find the output response Y(t)
to a unit step R(t)=1 , t≧0.
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