Question about "sit to stand with exo" model

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1

Can I ask a question about the script (AnyForce given to the actuator) in “Sit to Stand with exo” model?
What is the VelFactor here? why it should be calculated as that? Thanks a lot

AnyForce Ankle_Left =
{
AnyKinMeasureOrg& ref = Main.Model.ModelEnvironmentConnection.Robot_Measures.Ankle_Flexion_Left;
AnyVar Sign = iffun(gtfun(ref.Vel[0], 0.0), 1.0, -1.0);
AnyFloat VelLimit = 0.1;
AnyVar VelFactor = iffun(gteqfun(abs(ref.Vel[0]), VelLimit), 1.0, sin(abs(ref.Vel[0])/VelLimit(pi/2)) );*
F = Sign * VelFactor * ACTUATOR_FACTOR_ANKLE * {ref.Pos[0]};
};

2

Hi Longbin,

I will try to answer but this feature of the model is also new to me, I understand that these equations can be hard to read.

The equations essentially says.

if the the velocity ref.Vel[0] is larger than or equal to VelLimit, then it will return 1 as the factor if not it will return the sinus equation.

So essentially it is a factor which relates to the speed ankle joint, if the speed is larger than the limit it will be 1 if it is less it will be gradually decrease from 1 as a sinus function.

So the factor will essentially reduce the help from the exo for lower speeds, that is how i understand the code.

Hope it makes sense.

Best regards
Søren

3

Hi Søren

Thanks. This helps a lot.

4

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