Transformation matrix of linear n-dimensional state-space system

In summary, the conversation discusses the use of a transformation matrix P for linear systems in control systems. The matrix P is formed using the controllability matrix M_c as a basis, assuming it is full rank. Another matrix, M_2, is constructed using the characteristic equation of the system. The transformation matrix is given by P^-1 = M_c M_2, and applying this transformation leads to a canonical form of the system. The conversation ends with a request for further explanation on how M_2 is used to transform into the canonical form.
  • #1
X89codered89X
154
2
Hi all,

I have a linear algebra question relating actually to control systems (applied differential equations)

for the linear system

[itex]

{\dot{\vec{{x}}} = {\bf{A}}{\vec{{x}}} + {\bf{B}}}{\vec{{u}}}\\
\\

A \in \mathbb{R}^{ nxn }\\
B \in \mathbb{R}^{ nx1 }\\
[/itex]

In class, we formed a transformation matrix P using the controllability matrix [itex] M_c [/itex] as a basis (assuming it is full rank).
[itex]

M_c = [ {\bf{B \;AB \;A^2B\;...\;A^{n-1}B}}]
[/itex]

and there is a second matrix with a less established name. Given that the characteristic equation of the system is [itex] |I\lambda -A| = \lambda^n + \alpha_1 \lambda^{n-1} +... + \alpha_{n-1}\lambda + \alpha_n= 0 [/itex], we then construct a second matrix, call it M_2, which is given below.

[itex]
{\bf{M}}_2 =
\begin{bmatrix}
\alpha_{n-1} & \alpha_{n-2} & \cdots & \alpha_1 & 1 \\
\alpha_{n-2} & \cdots & \alpha_1 & 1 & 0 \\
\vdots & \alpha_1 & 1 & 0 & 0\\
\alpha_1 & 1 & 0 & \cdots & 0\\
1 & 0 & 0& \cdots & 0 \\
\end{bmatrix}

[/itex]

then the transformation matrix is then given by

[itex]

P^{-1} = M_c M_2

[/itex]and then applying the transformation always gives.. and this is what I don't understand...

[itex]
{\overline{\bf{A}}} = {\bf{PAP}}^{-1} =

\begin{bmatrix}
0 & 1 & 0 & \cdots & 0 \\
0 & 0 & 1 & \cdots & \vdots \\
\vdots & \vdots & 0 & 1 & 0\\
0 & 0 & \cdots &0& 1\\
-\alpha_{1} & -\alpha_{2} & \cdots & -\alpha_{n-1}& -\alpha_{n}\\
\end{bmatrix}

[/itex]

Now I'm just looking for intuition is to why this is true. I know that this only works if the controllability matrix is full rank, which can the be used as a basis for the new transformation, but I don't get how exactly the M_2 matrix is using it to transform into the canonical form... Can someone explain this to me? thanks...All Right! I think I'm done editin LATEX ...
 
Last edited:
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  • #2
Would I do better posting this somewhere else in PF?
 

1. What is a transformation matrix?

A transformation matrix is a mathematical representation of a linear transformation, which is a function that maps points or vectors from one coordinate system to another.

2. What is a linear n-dimensional state-space system?

A linear n-dimensional state-space system is a mathematical model used to describe the behavior of a dynamic system in terms of a set of differential equations. It is commonly used in control theory and other fields of engineering.

3. How is a transformation matrix used in a linear n-dimensional state-space system?

In a linear n-dimensional state-space system, the transformation matrix is used to transform the state variables of the system from one coordinate system to another. This allows for easier analysis and control of the system.

4. How is the transformation matrix of a linear n-dimensional state-space system calculated?

The transformation matrix is calculated by finding the coefficients of the state variables in each differential equation of the system. These coefficients are then arranged in a matrix, with the state variables as columns and the differential equations as rows.

5. What is the significance of the transformation matrix in analyzing a linear n-dimensional state-space system?

The transformation matrix allows for the analysis of the behavior of a system in different coordinate systems, which can provide insight into the stability, controllability, and observability of the system. It also allows for the design of control strategies to manipulate the system's behavior.

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