Black-Nichols diagram of a linear dynamical system
black( sl,[fmin,fmax] [,step] [,comments] ) black( sl,frq [,comments] ) black(frq,db,phi [,comments]) black(frq,repf [,comments])
a continuous or discrete time SIMO linear dynamical system ( see: syslin).
real scalars (frequency bounds)
row vector or matrix (frequencies)
row vectors or matrices (modulus, phase)
row vectors or matrices (complex frequency response)
Black's diagram (Nichols'chart) for a linear system ( see: syslin).
sl can be a continuous-time or
discrete-time SIMO system. In case of
multi-output the outputs are plotted with different colors.
The frequencies are given by the bounds
fmax (in Hz) or by a row-vector
(or a matrix for multi-output)
step is the ( logarithmic ) discretization step.
(see calfrq for the choice of default value).
comments is a vector of character strings
db,phi are the matrices of modulus (in Db) and
phases (in degrees). (One row for each response).
repf matrix of complex numbers. One row for each
To plot the grid of iso-gain and iso-phase of
y/(1+y) use nicolschart().
Default values for
sl is continuous-time or
0.5/sl.dt (nyquist frequency)
sl is discrete-time.
//Black diagram with Nichols chart as a grid s=poly(0,'s'); Plant=syslin('c',16000/((s+1)*(s+10)*(s+100))); //two degree of freedom PID tau=0.2;xsi=1.2; PID=syslin('c',(1/(2*xsi*tau*s))*(1+2*xsi*tau*s+tau.^2*s.^2)); clf(); black([Plant;Plant*PID ],0.01,100,["Plant";"Plant and PID corrector"]); //move the caption in the lower right corner ax=gca();Leg=ax.children(1); Leg.legend_location="in_lower_right"; nicholschart(colors=color('light gray')*[1 1])