Hand Independence Exercises for Vibrato

While maintaining a steady, relaxed, warm, rhythmically controlled vibrato on any finger anywhere on the fingerboard, do all sorts of unrelated movements with the right hand:

1: without holding the bow (tap your head, scratch your leg etc)

2: holding the bow, but without it touching the strings

3. bowing on the strings

For example:

Practice starting the vibrato before the bow-stroke starts and also maintaining the vibrato after the bow-stroke has finished. Do these exercises on all different fingers, on all 4 strings, all over the fingerboard and with a metronome (to control the vibrato speed).