EEE342
Homework 6: State-space design method
Due: 11 June, 2023 (In class or by 2.00pm in SAC1019)
Consider the following systems:
1. 𝑧̈ + 5 𝑧̇ + 6 𝑧 = 𝑢
2. 𝑧̈ + 4 𝑧̇ + 5 𝑧 = 𝑢
3. 𝑧̈ +4𝑧 =𝑢
4. 𝑧̈ + 𝑧̇ − 2 𝑧 = 𝑢
For each system do the following:
!(#)
a) Calculate the transfer function %(#). What are the poles of the system?
b) Put the system in the state-space form:
𝑥̇ = 𝐴𝑥 + 𝐵𝑢
𝑦 = 𝐶𝑥
Define the state vector as 𝑥 = [𝑥& 𝑥' ]( where, 𝑥& = 𝑧, 𝑥' = 𝑧̇ , 𝑦 = 𝑥&
What are the A, B, C matrices for the system?
c) Compute the eigenvalues of the A matrix. Do this by hand. Do not use Matlab. [In
Matlab, you can use the ‘eig’ command to calculate the eigenvalues of a matrix].
d) Are the poles of the system and eigenvalues of the A matrix the same or
different?
e) Plot the step response.
[You can use the following Matlab commands:
sys = ss(A,B,C,0);
step(sys);
]
f) Now we want to construct the closed-loop system 𝑥̇ = (𝐴 − 𝐵𝑘) 𝑥 using the
feedback control law 𝑢 = −𝑘𝑥.
Find the gain vector 𝑘 so that the closed poles are located at [-1 -2]. Do this by hand.
Do not use Matlab. [In Matlab, you can use the command ‘place’ or ‘acker’ to
calculate the gain vector 𝑘.]
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