How to add the saccadic motion to Vizzy's Gaze controller

[plinioMoreno]

@pattacini,

We want to add the saccadic gaze motion to Vizzy. What are the requirements in order to do this?

[pattacini]

Hi @plinioMoreno,

The saccadic behavior is described in section II-D.3 of "A Cartesian 6-DoF Gaze Controller for Humanoid Robots".

Saccades are fast open loop movements of the eye bulbs that are achieved by sending position commands with very high reference speed.

Relevant code can be browsed here:

• Computation of set-points
• Transmission of control commands

Since the eyes are normally controlled in velocity for doing smooth pursuit, we need the so-called MIXED control mode, which is capable of accepting at the same time and blending together positions and velocity commands.

How does it work in brief? The position set-points received by the firmware are basically corrected at run-time by integrating the velocity commands. Therefore, aside from developing the saccadic control at high level, you're also required to implement in the firmware this special mixed mode.

You can find out more reading our Control Modes Specifications.

Alternatively, you might consider starting with a simpler implementation where you can switch to POSITION mode to commence a saccade, wait until it comes to a complete stop, to then switch back to VELOCITY mode. The final effect won't be as nice as if you use MIXED mode, but you may count this only as first release.

[pattacini]

Closing for now.