TF {control} | R Documentation |
Evaluate Transfer function Expressions
Description
TF
Evaluates a given transfer function expression in the s-domain
Usage
TF(str_expr)
Arguments
str_expr |
String expression containing the transfer function |
Details
TF
Evaluates a given transfer function polynomial expression in the s-domain.
The evaluation of the expressions are performed similar to symbolic math computations for polynomials.
A transfer function model is created as the result of the expression evaluation.
Thus, this is an alternative way of creating transfer function models following the natural math expressions
found in block diagrams. It also provides an alternative way to perform system interconnections. Only transfer
function models are currently supported for system interconnection using this function. System interconnections
for other models could be performed using the series
, parallel
, feedback
or connect
functions.
See the Examples section for further details.
Value
Returns an object of 'tf' class list with a transfer function. Numerator and denominator
coefficients could then be retrieved from the object the same way as any other tf
object
See Also
Examples
# Example taken from the GitHub page of Julia Control - an electric motor example
J <- 2.0
b <- 0.04
K <- 1.0
R <- 0.08
L <- 1e-4
P <- TF("K/(s*((J*s + b)*(L*s + R) + K^2))")
Cls <- TF("P/(1 + P)") # closed-loop connection
# More examples
TF("s+1")
sys1 <- tf(1, c(1, 2, 5))
sys2 <- tf(2, c(1, 2, 5))
TF("sys1 + sys2") # parallel system interconnection
TF("sys1 * sys2") # series system interconnection
TF("sys1 - sys2")
TF("sys1 - 1")
TF("sys1 + 1")
TF("sys1 - sys2 + sys2")
TF("sys1 / sys2 / sys2")