Gimbal lock

Hi,
I need some element to complete my model, so I ask you:

  1. Is it possible to give a driver to the ankle, therefore, is it
    possible to eliminate the constrain that ties the ankle to the floor
    in the standing model?

  2. How is it possible to eliminate the coordinate x of CoM?

AnyKinEqSimpleDriver CoMDriver = {
AnyKinCoM CoM = {
AnyFolder &Body = Main.Model.HumanModel;
};
MeasureOrganizer = {0,2}; // Only the x and z directions
DriverPos = {0.1,0};
DriverVel = {0,0};
Reaction.Type = {0,0};
};

  1. How can I make to straight back of my scheleton?
    it’s curved!
    do I work on the position of every vertebra?
    Or is there a more rapid way to do it?

  2. I have inserted a RotVector to the Glenohumeral joint, to
    eliminate the gimbal lock, could know how to do in order to the Ref
    refers to the global system?
    is it always possible to do it?
    or is it wrong?

AnyKinRotational GHRotR = {
AnyRefNode
&scapula_gh= …HumanModel.Trunk.SegmentsThorax.ThoraxSeg.ij;
AnyRefNode
&humerus_gh= …HumanModel.Right.ShoulderArm.Seg.Humerus.gh;
Type = RotVector;
AngVelOnOff = On;
};

Thanks so much
Raffaella

Hi Raffaella

Here are some answers to the questions:

  1. If you add one driver to the ankle you have to remove another
    driver in order to maintain the same number of driven DOF in the
    model. In principle it is possible to remove of the constraints that
    that controls the feet height over the floor and replace it with an
    ankle driver, but then you need to control the ankle driver in order
    to keep the foot falt on the floor.

  2. The xdof in the COm measure can be removed in the following way

AnyKinEqSimpleDriver CoMDriver = {
AnyKinCoM CoM = {
AnyFolder &Body = Main.Model.HumanModel;
};
MeasureOrganizer = {2}; // Only z directions
DriverPos = {0};
DriverVel = {0};
Reaction.Type = {0};
};

but remember to add another driver instead to keep the number of dof
balanced

  1. The flexion of the spine is contolled by the driver
    named “PostureDriver”. This driver drives the angle between pelvis
    and thorax. The vertebraes inbetween is adjusted using a spine
    rhythm. So you can only adjust the driver angles of the
    PostureDriver to make the spine it straight.

  2. It is allright to introduce other ways of driving the joints if
    these suit the purpose better than the ones defined in the model,
    thats is not a problem.

Best regards
AnyBody Support

— In anyscript@yahoogroups.com, “ing_bio982” <ing_bio982@y…>
wrote:
> Hi,
> I need some element to complete my model, so I ask you:
>
> 1. Is it possible to give a driver to the ankle, therefore, is it
> possible to eliminate the constrain that ties the ankle to the
floor
> in the standing model?
>
>
> 2. How is it possible to eliminate the coordinate x of CoM?
>
> AnyKinEqSimpleDriver CoMDriver = {
> AnyKinCoM CoM = {
> AnyFolder &Body = Main.Model.HumanModel;
> };
> MeasureOrganizer = {0,2}; // Only the x and z directions
> DriverPos = {0.1,0};
> DriverVel = {0,0};
> Reaction.Type = {0,0};
> };
>
>
>
> 3. How can I make to straight back of my scheleton?
> it’s curved!
> do I work on the position of every vertebra?
> Or is there a more rapid way to do it?
>
> 4. I have inserted a RotVector to the Glenohumeral joint, to
> eliminate the gimbal lock, could know how to do in order to the
Ref
> refers to the global system?
> is it always possible to do it?
> or is it wrong?
>
>
> AnyKinRotational GHRotR = {
> AnyRefNode
> &scapula_gh= …HumanModel.Trunk.SegmentsThorax.ThoraxSeg.ij;
> AnyRefNode
> &humerus_gh= …HumanModel.Right.ShoulderArm.Seg.Humerus.gh;
> Type = RotVector;
> AngVelOnOff = On;
> };
>
>
>
>
>
>
>
> Thanks so much
> Raffaella