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Homework 1: State Space Realization - Kckong.info

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6. Calculate e Ft and F k , where k is an integer, for the matrices:<br />

[ ] 0 0<br />

(a) F =<br />

1 0<br />

[ ] 4 3<br />

(b) F =<br />

1 2<br />

[ ]<br />

0 1<br />

(c) F =<br />

−3 −2<br />

7. Consider a matrix<br />

⎡<br />

F =<br />

⎢<br />

⎣<br />

0 1 0 0 0<br />

0 0 1 0 0<br />

0 0 0 1 0<br />

0 0 0 0 1<br />

−45 −111 −104 −48 −11<br />

⎤<br />

⎥<br />

⎦<br />

(a) Using the Matlab function eig.m, show that the eigenvalues of F are−1, −2±j, −3, and −3.<br />

(b) Find V ∈ R 5×5 such that 2<br />

where<br />

⎡<br />

A =<br />

⎢<br />

⎣<br />

F = VAV −1<br />

−1 0 0 0 0<br />

0 −2 1 0 0<br />

0 −1 −2 0 0<br />

0 0 0 3 1<br />

0 0 0 0 3<br />

(c) Noting that the matrix A consists of three block matrices, solve e Ft .<br />

(d) For a state space equation, ẋ = Fx, findx(1) for x(0) = [ 1 1 1 1 1 ] T .<br />

⎤<br />

⎥<br />

⎦<br />

8. Suppose a state space model is given byẋ = Fx, where F ∈ R 2×2 . Suppose it is known that<br />

[ ] [ ] [ ] [<br />

4 1 5 1<br />

x(1) = for x(0) = and x(1) = for x(0) =<br />

−2 1<br />

−2 2<br />

]<br />

(a) Find e Ft .<br />

(b) Find x(10) for x(0) = [ 1 0 ].<br />

9. Consider a quarter vehicle model shown in Fig. 1a, where u is the force (input) applied to the vehicle.<br />

(a) Find the equation of motion of the simplified model shown in the figure.<br />

(b) Defining x 1 as the output of the system, find a state space model corresponding to the equation of motion. 3<br />

In other words, find the matrices F ,G, and H with appropriate dimensions:<br />

ẋ = Fx+Gu<br />

y = Hx<br />

(c) Assuming M 1 = 1000, M 2 = 100, k 1 = 20000, k 2 = 15000, c 1 = 10000, and c 2 = 40000, find the<br />

eigenvalues and eigenvectors of the state matrix F by the Matlab function, eig.m.<br />

2 Since V ∈ R 5×5 , all the elements of V should be real.<br />

3 Hint: you may define the statexas [ x 1 x 2 ẋ 1 ẋ 2<br />

] T<br />

∈ R 4 .<br />

2

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