Re: Simulation of 3D pendulum


"Daniel " <p04dp@xxxxxxxxxxxxxx> wrote in message
news:fuias1$h2a$1@xxxxxxxxxxxxxxxxxxxxx
Ok, so what about starting with a really simple model.
* The pendulum's movement does not affect the anchorpoint
* The wire is not flexible nor elastic, lets approximate
it
with a "weightless" rod
* Uniform gravitational field with acceleration of 9.82
m/s/s as constant.

yeah, that simplifies it quite a bit. So what is your
question? you said you were doing some simulation and
needed some help... from your backtracking to a simple
model from what it sounds like you started from can i
assume that you really haven't been doing some
simulations?


What we have done so far:
Simulated the movement of the anchor-point, from this we
just simplified it all to that the wire hung straight down,
thus no pendulum effect.
Then we implemented a simple 2D pendulum with dampening on
small intervals. We know that the maximum angle of the
pendulum will be rather small so we thought of approximate
the wire with a thin "weightless" bar.
The problem is to model a 3D pendulum correctly with
dampening. I think we have an ok simulation of a 3d-pendulum
but without dampening.
I dont have the code right now, but will post it here as
soon as I can.

For 3D simulations, you really should be looking at using SimMechanics
(http://www.mathworks.com/products/simmechanics/), it will make your life a
lot easier. It only works for rigid bodies, but flexible bodies can be
approximated with a string of rigid bodies connected together. There is a
paper on MATLAB Central that goes through the details and provides examples
(http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=11027&objectType=file).

Hope this helps,

Arnaud


.

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