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Re: Steady state error
Posted:
Dec 12, 2012 3:18 AM


Sorry, the closed loop transfer function's steady state error is:
abs(1dcgain(sys))
If using an openloop transfer function, the function must first be closed abs(1dcgain(feedback(sys,1))) % for unity feedback Alternatively if using an openloop transfer function with unity feedback, then the steady state step error is 1/(1+dcgain(sys)) where dcgain(sys) is the static error constant Kp
"A" wrote in message <ka9drm$n60$1@newscl01ah.mathworks.com>... > The previous response to this is not correct. The steady state error can be calculated in two ways depending on the type of transfer function: > > abs(dcgain(sys)1) > for a closed loop transfer function > > > > Jon Carter <jdc298REMOVETHIS@soton.ac.uk> wrote in message <38E0D27C.619EB741@soton.ac.uk>... > > Hi > > > > I'm looking to calculate the steady state error of a transfer function > > with a unit step input in Matlab. I can do this by using step() to draw > > a plot of the response, but is there a function that would tell me the > > error without needing to read it off graphically? > > > > Thanks, > > > >  > > Jon > > jdc298REMOVETHIS@soton.ac.uk



