1 Crore+ students have signed up on EduRev. Have you? Download the App |
The state variable description of an autonomous system is, X = AX where X is a two-dimensional vector and A is a matrix given by
The eigen values of A are
Eigen values of A are given by
or, (s - σ)2 + ω2 = 0
or, s = σ ± jω
or, s = σ + jω and s = σ - jω
The system equations are given by
y(t) = [1 0]x(t)
The transfer function of the above system is
Given,
Transfer function of the given system is
Now,
∴
= s2 + 3s + 2
Now,
Now,
Consider the following statements related to state space analysis of control systems:
1. The zeros of the system can be obtained from eigen value of the system matrix.
2. A system is said to be observable if every state x0 can be exactly determined from the measurement of the output ‘y’ over a finite interval of time 0 ≤ t ≤ tf.
3. The process by which transfer function changes to state diagram or state equations is called decomposition of the transfer function.
4. The state space techniques can be applied to linear and time invariant systems only.
Which of the above statements are correct?
The poles of the system can be obtained from eigen values of the system matrix. Hence, statement-1 is false.
State space techniques can be applied to linear or non-linear, time variant or time invariant systems.
Hence, statement-4 is false.
Consider the system shown in figure below:
The system is
From given block diagram, the state equations can be written as:
x1 = -x1 + u and x2 = -2x2 + 2u
in matrix form,
Also, y = x1 + x2
In matrix form,
Thus,
Since, |Qc| ≠ 0 and |Q0| ≠ 0, therefore given system is both controllable and observable.
Given,
So, x(t) = ϕ(t).x(0)
= state transition equation
The transfer function of the system shown below is
From given block diagram, the state equations can be written as:
Also, output equation is
y = 2x1 + x2
In matrix form, we have:
and y = [2 1]x(t)
Now,
∴ Transfer function,
The state equation for the circuit shown below is
Let us select the state variables as Vc and iL.
Applying KVL in the mesh-2, we have:
or,
.............(1)
Also, by applying KCL at the given node, we get:
or,
..........(2)
From equations (1) and (2), state equations in matrix form can be written as:
The state space representation of the system represented by the SFG shown below is
The state equations from the given signal flow graph can be written as:
In matrix form,
Also, output is
y(t) = 6x1 + x2
In matrix form
The state variable representation of a system is given by:
The system is
Here,
So, IQCI = 0 - 0 + 2(0 - 4)
= - 8 ≠ 0
Hence, the system is controllable.
Also, Q0 = [CT ATCT (AT)2 CT]
Here,
and
So,
= 1 ≠ 0
Since |Q0| ≠ 0, therefore given system is observable.
T.F.,
Hence, zeros are at:
So, zeros are at:
or, -17 -5s + s2 + 9s + 20 = 0
or, s2 + 4s + 3 = 0
or, (s+1) (s+3) = 0
or, s = -1,- 3