continuous SISO system limit feedback gain
K=kpure(sys [,tol]) [K,R]=kpure(sys [,tol])
A SISO linear dynamical system, in state space, transfer function or zpk representations, in continuous or discrete time.
a positive scalar. tolerance used to determine if a root is imaginary or not. The default value is
Real vector, the vector of gains for which at least one closed loop pole is imaginary.
Complex vector, the imaginary closed loop poles associated with the values of
K=kpure(sys) computes the gains
K such that the system
sys feedback by
sys/.K(i)) has poles on imaginary axis.
Handling zpk representation