1. Part Feeding by Potential Fields
Attawith Sudsang and Lydia E Kavraki
Presented by Petter Frykman

2. Part Feeding, history Generally used devices
Vibratory bowls Placing the part in a specially designed bowl and let the vibrations orient the part. The bowl has to be redesigned for each part.
Trap doors Some kind of bowl with a special shape and a special shaped hole in the bottom. Also has to be redesigned for each part.

3. Part Feeding, now days Research topics
Vibratory bowls Trying to analyze the process of design.
Programmable part feeders Build more robust and general feeders that can be reprogrammed to be able to feed a new part. In micro scale by using MEMS actuators and in macro scale by using mechanical devices such as jet air thrusters or vibrating plates. (Also first papers parallel jaws.)

4. Potential Field
A force field that applies a force to every point on the part, that is towards a special center point and has magnitude equal to a constant times the distance to the center point. This force field is the same as a potential quadratic bowl.

5. Potential Fields
MEMS actuators and air thrusters These devices can be seen as programmable force fields or potential fields. The underlying idea is that a part that is lying in such field is driven towards a stable equilibrium by the resulting force and torque induced by the field, or to a potential local minimum for the part.
Squeeze fields By applying a sequence of squeeze fields to the part we can orient a polygonal part in a similar way as the first papers parallel jaws.

6. Potential Fields
Elliptical force field This field applies a force to each point of the part such that all points that is on the same elliptical contour will have the same magnitude of force. This field induces two stable equilibria.
Unit radial and small constant force fields The unit radial force field is a point p0 and every point p of the part will experience a force towards p0 that is equal in magnitude to the distance between p and p0. The small constant field is just a constant force that all points experience the same way. This field induces just one stable equilibrium.

7. Linear Radial Force Fields
…combined with constant force field The linear radial force field is a radial field like the unit radial field but the magnitude of the force is a linear function of the distance from p to p0. The combination of these two is a field defined by the magnitude of the constant field and the coefficients defining the linear function associated with the radial force field. For a given part there is a set of parameters for the field such that the field induces one stable equilibrium for the part.

8. How does that look?

9. and the theory…
The constant field can be split into two radial fields…

10. Split the field into two parts

11. Pivot Points

12. Pivot Points

13. Unique Stable Equilibrium