can i drive the lower extremity model using landmarks on one leg

Main Forum
1

Dear AnyBody:

As the title indicated, I have a few (13) markers placed on the trunk and right lower extremity. Can I still use them to drive a lower-body model?

Thanks,
-Phoebe

2

Hi,

I’m a Anybody user.

But I’m not Anybody supporters…

I think it is impossible.

One leg motion that you captured side is working well in Anybody.
(But that is wrong result of joint moments or reactions…)

The other leg motion that you didn’t capture side is not working.
And That make wrong results.

Because Anybody don’t know position about the leg that you didn’t capture side.

But,

  • If subject have a only one leg?
  • single stance with other leg fixed body.
  • Open kinetic chain exercises on the chair.
    …

I think, these case is possible.

Would you describe more detail information about the your motion in this forum?

3

Dear Phoebe,

It is up to how you would make some assumptions about your model.

If you are OK with excluding one leg which does not have any markers then it will be helpful to do that.

Also you can add some extra drivers on some DOFs so that you can make it working too.

Best regards,
Moonki

4

Thanks for your input. My collaborator acquired MoCap on one leg of a subject performing normal gait. I know it's not perfect since his experiment was designed for something else, but I guess I need to deal with whatever is available.

Thanks again.

5

Thanks Moonki. So all I need to do is to add extra drivers on the leg without markers? I usually use extra drivers for arms as below. Shall I do similar for the leg?

thanks!

-Phoebe

AnyKinEqSimpleDriver WristFlexionRight =
{
AnyKinMeasureOrg &ref3 =...BodyModel.Interface.Right.WristFlexion;
DriverPos = pi/180*
{
.JntPos.Right.WristFlexion
};
DriverVel =
{
.JntVel.Right.WristFlexion
};
Reaction.Type={Off};
CType = {Soft};
};
AnyKinEqSimpleDriver WristAbductionRight =
{
AnyKinMeasureOrg &ref3 =...BodyModel.Interface.Right.WristAbduction;
DriverPos = pi/180*
{
.JntPos.Right.WristAbduction
};
DriverVel =
{
.JntVel.Right.WristAbduction
};
Reaction.Type={Off};
CType = {Soft};
};
AnyKinEqSimpleDriver ElbowPronationRight =
{
AnyKinMeasureOrg &ref3 =...BodyModel.Interface.Right.ElbowPronation;
DriverPos = pi/180*
{
.JntPos.Right.ElbowPronation
};
DriverVel =
{
.JntVel.Right.ElbowPronation
};
Reaction.Type={Off};
CType = {Soft};
};

6

Hi Phoebe,

You can do it two ways, either exclude the leg or add some extra drivers like you write that will drive the leg.

I would prefer to remove it, it will not be easy to drive it naturally and i do not see what is gained by doing it.

Best regards
Søren