# Hand Trajectory

Hi all,

I know It is possible to change the values in “PostureVel” of “Mannequin.any” file to make a motion. Actually, we can change the values of joint in shoulder and elbow to make the end of the hand (end-effector) have a motion (track a path). -like forward problem-

But my question is about Inverse Problem :
Is it possible to give a trajectory to the hand (end-effector) and see what the joints velocities will be?

In fact, the problem is to fix the feet then the right hand follows a path carrying an object. Then see what the joint velocities are, which muscles and segment are involved and how much energy needed to do that.

Hi,

You can make a trajectory of the hand.

First you should define a kinematic measure of the hand with respect to the global coordinate system. I recommend you to use the ‘AnyKinLinear’ class.
And you can use that kinematic measure for your driver.

Best regards,
Moonki

I used “AnyKinLinear” to create the marker.
Now, how can I use the driver to make the marker move on the desired path in 3 dimensional space?
I mean how can I give the formula of a path in 3 dimensional space to a driver in anybody?

In “AnyKin…” drivers, “DriverPos” and “DriverVel” get just constant value (no equation)?

Sorry if the questions does not seem very good. I am a beginner.
Thanks.

Hi,

There are several driver classes which you can use in AnyBody:
AnyKinEqSimpleDriver
AnyKinEqFourierDriver
AnyKinEqInterPolDriver
AnyKinEqPolynomialDriver
AnyKinDriverMarker

If you want to driver a target using some measured data,
then I would recommend you to use AnyKinEqPolynomialDriver.

If you want to define a mathematical formula of the trajectory,
then AnyKinEqPolynomialDriver or AnyKinEqFourierDriver can be used.

Also there are many class examples of AnyBody in the following folder of your computer:
C:\Program Files\AnyBody Technology\AnyBody.6.0\Documentation\AnyScriptReference\demo\ClassExamples

Best regards,
Moonki

Thanks
But I could not find any example to drive the marker by mathematical equation.

Actually, I use the following code to drive the marker

``````        AnyKinEqPolynomialDriver PalmMotion = {
AnyKinLinear PalmMarker = {
AnyFixedRefFrame &Ground =Main.Model.Environment.GlobalRef;
AnyRefNode &Palm = Main.HumanModel.BodyModel.Right.ShoulderArm.Seg.Hand.PalmJoint;
Ref = 0;
AnyDrawKinMeasure Drw = { };
};

PolyCoef = {{0.2,0,0},
{0,1.2,0},
{0,0,0.2}};
``````

// The above Poly equation is for Position, Velocity or Acceleration???
Reaction.Type = {Off,Off,Off};
};

And the following code to fix the Pelvis

AnyStdJoint FixedPelvis = {
AnyRefFrame& Seat =Main.Model.Environment.GlobalRef.Hpoint ;
AnyRefFrame& Pelvis = Main.HumanModel.BodyModel.Trunk.SegmentsLumbar.PelvisSeg;
};

But this adds 9 more constraints (3 from marker drivers and 6 from Pelvis fixation) than the DOF.
Moreover, I receive the following error when running the application

ERROR(OBJ.MCH.KIN3) : D:/A…y/D…y/A…o/A…n/M…s/P…r/Pickup.main.any(57) : Study.InitialConditions : Kinematic analysis failed in time step 0

May anybody hep

Hi,