Hi,
I'm trying to get a component to perform a Fractional Derivative in MapleSim to use in a multibody simulation (as a spring-dash pot component). However, I'm stumped by trying to get the fracdiff function past the custom component code.
- When set to series, the fractional derivative is only accurate near the estimated about point
- When set to LaPlace, it's impossible to perform the transform when the incoming signal is not yet defined (and can be completely random)
- When set to Direct, the Modelica code does not compile (due to the integral syntax)
The next option I was trying was the Grunwald-Letnikov definition
(Approximated with n = 150 or less, and alpha is the order between 0 and 1). But I run into two problems; The gamma function isn't defined in the Modelica code, and I'm not sure about accessing previous values of the function. (This definition is numerical approximation that is basically the weighted-sum of previous values).
Now I'm just wondering, is this possible in a MapleSim simulation or do I have some fundamental assumption wrong? In the mean time I'll be catching up on the Modelica specifications.
Any advice or guidance would be much appreciated.
Thanks! - ekyam
