Filter
Top Products
3.2. DATA OBJECTS 73
As above, these polynomials can be specified by their roots or their coefficients. Note
that we can specify the variable, and for continuous systems we use “s”. To create a
discrete system “z” is used.
# Generate the system from the numerator and denominator
# coefficients.
numerator = makepoly([-.1,19.97,-7.02725],"s");
denominator = makepoly([1,0.3,0.2725],"s");
# We can also do this by specifying the roots of each
# polynomial
numerator = -0.1*polynomial([199.3475;0.3525],"s");
denominator = polynomial( ...
[-.15+0.5*jay;-.15-0.5*jay],"s");
# Note that multiplying the by -0.1 does the correct
# thing to the polynomial above. The final system is
# obtained with the command:
sys1 = numerator/denominator
Labeling and Comments
Xmath allows the user to label all the inputs, outputs and states in a state-space system.
Any Xmath variable can also have a comment string associated with it.
Keywords for the system function are used to label the system. In the following
example, the two-input, single-output system generated above is used as the starting
point. Comments can be attached to any variable in the workspace (or the workspace
itself) with the comment command.
# Set up vectors of strings for the labels
inputs = ["disturbance";"actuator"]
outputs = ["measurement"]
states = ["x1";"x2"]
# and attach them to sys
sys = system(sys,inputNames = inputs,...
outputNames = outputs,...
stateNames = states)
# We can also attach a comment to sys
comment sys "Example system for the manual"