My question deals with force plates. I have read through the Wiki on it, by the way, and it does not seem to address my specific situation.
So, my question is: If a person is not moving their legs, how do you set up the force plates? I can not use the AutoDetection set up, can I? There is no sequence, so the Basic set up won’t work either.
Pertinent information:
Using Mokka, I figured out the force platform type (TYPE, in the FORCE_PLATFORM label) had an integer value of 4. A CAL_MATRIX also exists in the Metadata for the mocap file. The manufacturer happens to be Qualisys. Finally, visualizing the mocap, Z-axis happens to be the upright direction and there are two force plates.
With that in mind, I changed the AnyVector Gravity in TrialSpecificData.any to reflect the gravity in Z direction as follows:
AnyVector Gravity = {0, 0, -9.81};
Also, the VerticalDirection in ForcePlates.any is specified to be “Z”.
Based on your description, you can use either ‘ForcePlateType4AutoDetection’ or ‘ForcePlateType4’ class template.
The only difference is that ForcePlateType4AutoDetection class template will detect which foot is on that force plate at each time frame. So it will work even if the person is not moving.
Also your guess about Gravity and VerticalDirection is correct.
So based on your comments, I can’t see any problem in using our force plate class templates for your applications.
By the way, I thought you might want to add a line to the Wiki talking about force plates (for beginners) saying that there may be situations where the naming convention might be different in the force/moment components which the MoCap model (i.e., AnyBody) may not recognize and spit out an error.
In my case, all I had to do was to change Fx1 to F1x.
I wrote that page a while ago and just added a line to the forceplates about name convention. I will go over it once i find little more time. Any feedback is much appreciated!!!