Control package

The control package is part of the Octave Forge project.

Function list

Linear System Representation

Chapter	Function	Implemented	File	Status
Basic Models	tf	yes	@tf/tf.m
	zpk	yes	zpk.m
	ss	yes	@ss/ss.m
	frd	yes	@frd/frd.m
	pid	no
	pidstd	no
	pid2	no
	dss	yes	@lti/dss.m
	drss	no
	filt	yes	filt.m
	rss	no
Tunable Models	ltiblock.gain	no
	ltiblock.pid	no
	ltiblock.pid2	no
	ltiblock.ss	no
	ltiblock.tf	no
	realp	no
	AnalysisPoint	no
	genss	no
	genfrd	no
	genmat	no
	getLoopTransfer	no
	getIOTransfer	no
	getSensitivity	no
	getCompSensitivity	no
	getPoints	no
	replaceBlock	no
	getValue	no
	setValue	no
	getBlockValue	no
	setBlockValue	no
	showBlockValue	no
	showTunable	no
	nblocks	no
	getLFTModel	no

Some very basic examples

PT1/low-pass filter step response

Code: Creating a transfer function and plotting its response

T1=0.4; # time constant P=tf([1], [T1 1]) # create transfer function model step(P,2) # plot step response #add some common markers like the tangent line at the origin, which crosses lim(n->inf) f(t) at t=T1 hold on plot ([0 T1], [0 1],"g") plot ([T1 T1], [0 1],"k") plot ([0 T1], [1-1/e 1-1/e],"m") hold off

Try also bode(P)! (a first order low-pass filter has -3db magnitude at f=1/T1)