Hi everyone,

I have a problem comprehending the transformation sequence of hip joint angles (GaitFullBody of AMMRV1.3.1). In order to visualize the rotation axes and their orientations I included a AnyDrawRefRame function in the HipJointStandard definition:

AnyVec3 HipJointStandard= {0.0, 0.0, …Sign*0.0};
AnyRefNode HipJoint = {
sRel = .Scale(.HipJointStandard);
ARel = RotMat(…Sign*-30

*pi/180,y) * RotMat(-18*pi/180,z);

AnyDrawRefFrame drw =

{ RGB = {1, 0, 0}; };

};

(AMMRV1.3.1\Body\AAUHuman\LegTD\Seg.any)

In order to understand the sequence I ran through a bunch a different sequences:

Flexion, abduction, and rotation occur around their corresponding axes.

pure flexion/abduction/rotation: the corresponding axis remains at the same place and the others turn around it (makes sense)

first flexion -> then abduction: new orientation for abduction axis after flexion; no new orientation while abduction (makes sense)

first flexion -> then rotation: new orientation for rotation axis after flexion; no new orientation while rotation (makes sense)

first flexion -> then abduction -> then rotation: y-axis is not stable but rotates after all rotations (does not make sense to me)

Therefore I do not understand around which axis the hip rotates.

Besides the code above indicates that the rotation is first around z and then y. I do not find abduction (x) in here.

I would be very grateful for an answer helping me to understand around which axis which motion direction occurs and in which order the rotations are performed.

Thank you very much in advance,

Fabian