Matlab: Some common function for Machatronic Engineer

1. Step - Step response plot of dynamic system

    This MATLAB function plots the step response of an arbitrary dynamic system
    model sys.

    step(sys)
    step(sys,Tfinal)
    step(sys,t)
    step(sys1,sys2,...,sysN)
    step(sys1,sys2,...,sysN,Tfinal)
    step(sys1,sys2,...,sysN,t)
    y = step(sys,t)
    [y,t] = step(sys)
    [y,t] = step(sys,Tfinal)
    [y,t,x] = step(sys)
    [y,t,x,ysd] = step(sys)
    [y,...] = step(sys,...,options)

2. Hold - Retain current plot when adding new plots

    This MATLAB function retains plots in the current axes so that new plots added
    to the axes do not delete existing plots.

    hold on
    hold off
    hold all
    hold
    hold(ax,'on')
    hold(ax,'off')
    hold(ax)
3. rlocus
 Here is an example of how the function rlocus works:
 Consider a randomly generated stable Transfer Function Model:
 of the form G(s)=num(s)/den(s):

num =

         0   -0.1022    0.0316    0.1934   -0.1795    0.1620


den =

    1.0000    6.2190   50.6538  222.7866  359.5180  162.7478

Call rlocus using the following command (see also, help rlocus):
rlocus(tf(num,den));