Why the angular velocities measured by bushing joint and transform sensor are different

I built a model of parallel manipulators using simMechanics, but I found that the angular velocities of the moving platform measured by bushing joint and transform sensor are different, so why?

[Devineni Aslesha]

In the given plot, I would like to know which plot corresponds to bushing joint and transform sensor. Also, would like to know how the angular velocity is measured. Is it the magnitude of angular velocity or the angular velocity in a particular direction?

[Chong Zhao]

Thank you for your answer. I was measuring the angular velocities in a X/Y/Z direction, as shown in the figure below. But the wx/wy/wz in the transform sensor and wx/wy/wz in the bushing joint were different.

Answer 1

[Harshal Upadhyay]

Bushing joint seems to be using Euler parametrization(refer to the Joint Transformation Sequence). https://www.mathworks.com/help/physmod/sm/ref/bushingjoint.html

Bushing Joint angular velocities would be about inermediate axes. Tranform Sensor values would be components of Omega in base/follower XYZ.

[Chong Zhao]

Got it. Thank you very much.