This was a collaborative project with Richard Pringle based on some ideas I had about building a modular haptic device that could work on a tablet display. In many ways this was the predecessor to the Haplet.
The objective was to create a device that could reconfigure itself to adapt the dynamic properties that the user would feel at the end-point.
The Archimedean spiral linearly maps the angular displacement of the spiral plate to the translation of the motors along an axis.
Here, and correspond to the desired ratio of linear to angular displacement, and, corresponds to a constant offset of the linear motion in the y-axis.
We can see here the simulated trajectory with zero y-axis offset with a 3 cm displacement over 2.5 revolutions:
and one with a 1 cm y-axis offset with a 3 cm travel over 1.5 rotations:
You can see the device in action: