control.matlab.feedback

control.matlab.feedback(sys1, sys2=1, sign=-1, **kwargs)[source]

Feedback interconnection between two I/O systems.

Parameters:

sys1, sys2scalar, array, or InputOutputSystem: I/O systems to combine.
signscalar, optional: The sign of feedback. sign=-1 indicates negative feedback (default), and sign=1 indicates positive feedback.

Returns:

outInputOutputSystem: Feedback interconnection of the systems.

Other Parameters:

inputs, outputsstr, or list of str, optional: List of strings that name the individual signals. If not given, signal names will be of the form ‘s[i]’ (where ‘s’ is one of ‘u’, or ‘y’). See InputOutputSystem for more information.
statesstr, or list of str, optional: List of names for system states. If not given, state names will be of of the form ‘x[i]’ for interconnections of linear systems or ‘<subsys_name>.<state_name>’ for interconnected nonlinear systems.
namestring, optional: System name (used for specifying signals). If unspecified, a generic name ‘sys[id]’ is generated with a unique integer id.

Raises:

ValueError: If sys1 does not have as many inputs as sys2 has outputs, or if sys2 does not have as many inputs as sys1 has outputs.
NotImplementedError: If an attempt is made to perform a feedback on a MIMO TransferFunction object.

See also

append, interconnect, negate, parallel, series

Notes

This function is a wrapper for the feedback function in the I/O system classes. It calls sys1.feedback if sys1 is an I/O system object. If sys1 is a scalar, then it is converted to sys2’s type, and the corresponding feedback function is used.

Examples

>>> G = ct.rss(3, inputs=2, outputs=5)
>>> C = ct.rss(4, inputs=5, outputs=2)
>>> T = ct.feedback(G, C, sign=1)
>>> T.ninputs, T.noutputs, T.nstates
(2, 5, 7)