Pedal force using in GaitFullBody

Main Forum
1

Hi, AnyBody supports,

I have some question about using GaitFullBody model.
I had an experiment of Elliptical Trainner, and I improve the pedal myself just like the attachment.

There are four LoadCell using to measure the force when stepping the Elliptical Trainner, the function just like the forceplate.
After experiment and Matlab measuring, I can get COP location in the Global and vertical force from the LoadCell.
I mad a segment using InterPolDriver and AnyKinLinear to put in the COP,
and use AnyReacForce to connect the foot and the segment, then use AnyForce3D to put the force in the segment.
I want to analyse the knee joint, and there’s no forceplate on the machine,
so can you just take a look in my code, and tell me if the idea is correct or…

My AMS is ver 5.0 and AMMR is ver 1.3

Thanks first
Best regards,
Yeh

2

Hi, AnyBody support,

I have modify some code in it,

    AnyFunInterpol RightGRFfun = {
      Type = PiecewiseLinear;
      FileName ="S1Force.txt";
    };
      
    AnyForce3D RightGRF = {
      AnyRefFrame &Platform = .RightPedal;
      Flocal = .RightGRFfun(t);
    };

modify to


    AnyForce3D RightPedalForce = { 
      AnyFunInterpol load = {
        Type=PiecewiseLinear;
        FileName = "S1ForceN.txt";
      };       
    
      AnyRefFrame  &ref =.RightPedal;
      Flocal = load(t); 
    };

I read some same problem to me in the forums, and I found that in txt file, the value needs to be Newton, so I fix the file also.
But just what I know, the forceplate in the beginning have only 1.2 times of his weight, so it shouldn’t be overload like the attachment.

So can you help me check what’s the problem there in my model, please.

Thanks :slight_smile:
Best regards,
Yeh

3

Hi Yeh,

  1. I can’t tell anything about your experiment environment because I don’t know it. But it seems that the force data from load cell only contains the normal force, not friction force. This may be one reason of incorrect input data for inverse dynamics analysis.

  2. Also you don’t have the force input data for the left leg. Of course in the pelvis there are pelvis residual forces and moments to correct the balance. But this may be a second reason.

I would suggest you to improve these input information.

Best regards,
Moonki