pasky

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These are questions asked by pasky

Hi! I'm having trouble with the MapleSim "Equation Extraction" template. I have an extremely simple dynamics scenario with RigidBody at a particular position in a world; when the simulation starts, the body should simply start fallin with a constant acceleration, and I'm looking to extract kinematic equations for this situation.

However, the problem I have with the extracted equations is that they contain some rotational dependent terms that I wish to avoid - a lot of sines and cosines with arguments that I actually cannot match up to any variables in the model, or when I enable quaternion representation, terms like this:

What I don't understand is what exactly these rotation terms represent. The object should be falling straight downwards, and gravitation should be applied straight downwards, and when I start the simulation it does run through, also indicating that there should be no unbound variables. I'm not sure exactly what parameters in the Modelica model do they correspond to? I did not find any such angles in the object settings. And can I ask MapleSim to generate equations without these unbound rotation variables?

Hi! I'm trying to use MapleSim 7 to simulate some very simple physical situations, however after great many hours spent at this, I'm still unable to convince MapleSim to load and run even the simplest Modelica models, like:

model Main
  Modelica.Mechanics.MultiBody.Parts.Body o(r_CM = zeros(3));
  inner .Modelica.Mechanics.MultiBody.World world;
equation
  o.frame_b.f = {0,-9.8,0};
end Main;

It will report that o and world are "unknowns" and apparently does not recongize Modelica.Mechanics.MultiBody.Parts.Body nor Modelica.Mechanics.MultiBody.World. Do I need to do some extra steps to import extra libraries or enable some non-default components?  I went through various YouTube and other tutorials and didn't find a mention of anything.

When I look at some examples, often they refer to things like Maplesoft.Multibody.World - but these are proprietary Maple packages, and I need my code to use standard Modelica. Does this mean that MapleSim cannot run generic Modelica code like this?

I also tried running e.g. https://github.com/xogeny/HarmonicMotion and some other examples, with absolutely no success either. I'm quite confused because MapleSim has a lot of advertising about Modelica support... :-(

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