Calculation of joint forces in new coordinate system

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1

Hello,
I want to use joint force data of the hip calculated from a MoCap Gait trial to move a robot. However, the coordinate systems of the robot and the model do not align.
I ceated a custom pelvis node and a custom thigh node that represent the coordinate system of the robot. Example for the pelvis one below:

Main.HumanModel.BodyModel.Trunk.SegmentsLumbar.PelvisSeg = {
AnyRefNode PelvisNodeISB = {
    
    // 1. ORIGIN
    sRel = .Right.HipJoint.sRel;

    // 2. LANDMARKS
    AnyVec3 RASIV = .Right.ASIS.sRel;
    AnyVec3 LASIV = .Left.ASIS.sRel;
    AnyVec3 RPSIV = .Right.PSIS.sRel;
    AnyVec3 LPSIV = .Left.PSIS.sRel;

    AnyVec3 ASIS_mid = (RASIV + LASIV) / 2.0;
    AnyVec3 PSIS_mid = (RPSIV + LPSIV) / 2.0;

    // 3. AXES CALCULATION
    AnyVec3 Z_raw = RASIV - LASIV;
    AnyVec3 Z_axis = Z_raw / vnorm(Z_raw);

    AnyVec3 Ant_raw = ASIS_mid - PSIS_mid;

    AnyVec3 Y_raw = cross(Z_axis, Ant_raw);
    AnyVec3 Y_axis = Y_raw / vnorm(Y_raw);

    AnyVec3 X_raw = cross(Y_axis, Z_axis);
    AnyVec3 X_axis = X_raw / vnorm(X_raw);

    // 4. COORDINATE SYSTEM DEFINITION
    ARel = {X_axis, Y_axis, Z_axis}';

    // 5. VISUALIZATION magenta
    AnyDrawRefFrame DrawISBFrame = {
        ScaleXYZ = {0.15, 0.15, 0.15};
        RGB = {1, 0, 1}; 
    };
};
};

Then I created a custom joint with these two nodes:

 
    AnyFolder CustomHipJoints = {

AnySphericalJoint RightHip = {
AnyRefNode &ThighNode = Main.HumanModel.BodyModel.Right.Leg.Seg.Thigh.ThighNodeISB;
    
    AnyRefNode &PelvisNode = Main.HumanModel.BodyModel.Trunk.SegmentsLumbar.PelvisSeg.PelvisNodeISB;
};


AnySphericalJoint LeftHip = {
    
    
    AnyRefNode &ThighNode = Main.HumanModel.BodyModel.Left.Leg.Seg.Thigh.HipJoint;
    
    AnyRefNode &PelvisNode = Main.HumanModel.BodyModel.Trunk.SegmentsLumbar.PelvisSeg.Left.HipJoint;
};
};

How do I get the joint force caluclations for this custom joint? It’s not automatically calculated during the inverse dynamics study.

Or is there a completely different approach?

Thanks in advance
Christoph