How to make sense of the continuous state vector?

Question

Background

I am trying to balance a mobile inverted pendulum (i.e. segway).

For the simulation, I created a simple robot that involves a pole attached to a cyl

Answer 1

From Spatial Velocity

Spatial velocities are 6-element quantities that are pairs of ordinary 3-vectors. Elements 0-2 are the angular velocity component while elements 3-5 are the translational velocity.

From QuaternionFloatingMobilizer

  // Note: In the context we store the quaternion's components first (q₀ to q₃),
  // followed by the position vector components (q₄ to q₆).