# Reconfigurable Planar Haptic Device

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.

$x= \frac{\alpha}{\beta}\theta cos(\theta) + \gamma sin(\theta)$

and

$y= -\frac{\alpha}{\beta}\theta sin(\theta) + \gamma cos(\theta)$

Here, $\alpha$ and $\beta$ correspond to the desired ratio of linear to angular displacement, and, $\gamma$ 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: