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When I first looked at the translation functions 1 and 2 for the knee, I saw that the independent variable axis had a range of -2.31 to 2.31. I assumed the units were in radians but it appears that 1 unit is about 57 degrees. Specifically:

Knee flex 120 degrees = -2.095 units => 57.3 degrees/unit
Knee flex 90 degrees = -1.58 units => 57 degrees/unit
Knee extension 10 degrees = 0.17692 units => 56.5 degrees/unit

Is this right?

All (rotational) coordinate values are in radians. The X & Y translation splines in the Gait2392 model have a range or -2.094 to 2.094; those values are in radians. The independent coordinate (knee flexion) clearly doesn't have that range (-2.094 to 0.174 radians).

1 radian = 57.2958 degrees
2.0943951 radians = 120 degrees
0.17453293 radians = 10 degrees