Force plate knowledge for Input

Main Forum
1

Hi there

I’m Chris and I’m quite new with AnyBody. I just started my master thesis which is about a motion analysis of different running styles via Simi and AnyBody.
So far everything worked fine. But for further steps I need some more infos of the force plate implementation, because our lab would like to buy new equipment(if necessary).

I read the wiki docu regarding the “NEW: How to setup your own Mocap Model”, TrialSpecific.any and also Forceplate.any.
And it seems that all my force plate date is also in my C3D file. So AnyBody simply extract the force data of Fx,Fy,Fz,Mx,My,Mz. Unfortunately, our treadmill from zebris only messures the force in y-direction wich is othogonal to the surface. Is there any option to use just this force and even get a good inverse calculation? (I know that mathematical these are suboptimal conditions for an inverse dynamic analysis)

Several times I read something about different types of force plates. Is there a detailed docu with a good description available somewhere here? What do these types mean?

Sorry if there is already a tread of this topic. But I couldn’t find one.

Thank you very much for your help.

Best regards
Chris

2

Hi Chris,

Please search the forum for treadmill there are some previous examples on this.

I found this post which seem to contain a model which contains a treadmill model with forceplates maybe there is something there you can use.

http://forum.anyscript.org/showthread.php?t=3305&highlight=treadmill

Generally you will need to
[li] use fullbody mocap
[/li][li] predict the forces you did not measure using GRF predictions please wiki pages on this topic anyscript.org
[/li]

Please also have a look at this info
http://www.gaitposture.com/article/S0966-6362(16)00006-0/abstract

and this webcast

Ground reaction force prediction with the AnyBody Modeling System ( Assoc. Prof. Michael Skipper Andersen and Sebastian Skals, M.Sc., Aalborg University, 06. October, 2015)

Concerning the different types of plates please have a look at c3d.org in the forceplate section of the documentation, the type number basically defines the format of the output from the plates.

Best regards
Søren

1 Like
3

Thank you very much.
This will help me a lot.

4

Hello again :),

I am totally confused about this warning message. It doesn´t matter what I´m doing this is always what occurs:

WARNING(OBJ.MCH.MUS1) : C:/U…s/N…e/D…p/A…2/A…E/A…e/A…0/A…n/E…s/5…t/1_KneeDemo_Test.any : Study : The muscles in the model are not loaded due to kinetically over-constrained mechanical system.

I read this chat where the model has the same error message:

http://forum.anyscript.org/showthread.php?t=3728&highlight=kinetically+over-constrained+mechanical+system

But both solutions didn´t helped me, it´s still the same message.

My model is still a model of the lower Extremity sitting in a leg press (static case! It has no motion) with an external load at the ankle to analyze joint forces.
Attached you find a simple model, with just one muscel around the hip. This must be working or what am I doing always wrong?:confused:

Best Regards
Nathalie

5

I´m so sorry this is the wrong chatroom :o:eek:
I will post this again in the right one!!!