control.matlab.tf2ss

control.matlab.tf2ss(sys)

Transform a transfer function to a state space system.

The function accepts either 1 or 2 parameters:

tf2ss(sys)

Convert a linear system into space space form. Always creates a new system, even if sys is already a StateSpace object.

tf2ss(num, den)

Create a state space system from its numerator and denominator polynomial coefficients.

For details see: tf()

Parameters

• sys (LTI (StateSpace or TransferFunction)) – A linear system

• num (array_like, or list of list of array_like) – Polynomial coefficients of the numerator

• den (array_like, or list of list of array_like) – Polynomial coefficients of the denominator

• inputs (str, or list of str, optional) – List of strings that name the individual signals of the transformed system. If not given, the inputs and outputs are the same as the original system.

• outputs (str, or list of str, optional) – List of strings that name the individual signals of the transformed system. If not given, the inputs and outputs are the same as the original system.

• name (string, optional) – System name. If unspecified, a generic name <sys[id]> is generated with a unique integer id.

Returns

out – New linear system in state space form

Return type

StateSpace

Raises

• ValueError – if num and den have invalid or unequal dimensions, or if an invalid number of arguments is passed in

• TypeError – if num or den are of incorrect type, or if sys is not a TransferFunction object

See also

ss, tf, ss2tf

Examples

>>> num = [[[1., 2.], [3., 4.]], [[5., 6.], [7., 8.]]]
>>> den = [[[9., 8., 7.], [6., 5., 4.]], [[3., 2., 1.], [-1., -2., -3.]]]
>>> sys1 = ct.tf2ss(num, den)

>>> sys_tf = ct.tf(num, den)
>>> sys2 = ct.tf2ss(sys_tf)