# Add moment to the exo

Hi

I want to know how to use AnyFunInterPol to add torque to the exoskeleton. Could you tell me how to use it？Any help would be great appreciate.

Best wishes
BBJ

Hi @BBJ

You can find the documentation for each of the classes in the AnyBody Modeling System when you open the program and look under help -> AnyScript Reference.
Here you can look up the individual classes and also browse our small class examples like the one I have attached here:
ClassExamples.AnyFunInterPol.zip (2.2 KB)
This will help you learn to use the `AnyFunInterPol` class.

Best regards,
Bjørn
AnyBody Technology

Hello Bjorn, can you tell me, for example, how I can introduce the effect of an exo (with a function) on the upper arm.

For example, a torque curve (parabolic) should be applied. The vertex of the parabola should be at 90 degrees (angle between upper arm and upper body), for example.

I use MoCap Data

Many thanks in advance
Samuel

You can make such a function in different ways.
You could use our `AnyMoment3D` or `AnyForce3D` classes to apply moments or forces to the model.
The moments/forces can be made arbitrary functions you define and they can also incorporate other kinematic measures (e.g. a function of the angle between the arm and torso)
You can learn about the classes in the reference manual that you will find under: `Help -> AnyScript Reference Manual` in the top toolbar of the AnyBody Modeling System GUI.

Best regards,
Bjørn
AnyBody Technology

Hi Bjørn

Thank you very much for your reply.I follow this example and try to apply moment to the exoskeleton.
My code is as follows：
AnyFolder Exo = {
AnyFunInterpol moment =
{
Type=Bspline;
T={....};
Data={{...}};
};
};
AnyForce exomoment =
{
F = Main.Model.Exo.moment(t);
AnyKinMeasure &knee =Main.Model.Robot_Measures.Knee_Flexion_Right;
};
I got this error when I ran ： 'F' : Error in expression. Please refer to the following error messages for details ... moment : Parameter has an invalid value for this interpolation; extrapolations are not allowed. I may not understand this example well. Could you tell me how to modify it? Any help would be great appreciate.

Best wishes
BBJ

Hi @BBJ

From your example it looks like your `moment` function do not have any data in the `T` & `Data` variables.
You must type in some data, point to another variable, or load it in from a file.

Best regards,
Bjørn
AnyBody Technology

Hi Bjørn
Thank you for your reply. I added data to Data and T, but I didn't write it here. Could you tell me how to solve the above two errors? Thank you in advance.

Best regards,
BBJ

Ah I see, that is of course fine.
The errors says you are extrapolating instead of interpolating so the lowercase `t` variable is probably higher than than the values in the `Data` variable.

Best regards,
Bjørn

Thanks for the great information for a newbie.. .

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