View source for Vinutha Kallem, April 2008

Vinutha Kallem is a PhD student at Johns Hopkins who is visiting on 28-29 April 2008.  __NOTOC__

=== Schedule ===
{| width=100%
|- valign=top
| width=50% |
==== Monday ====
{{agenda begin}}
{{agenda item|9:30a|Richard}}
{{agenda item|10:00a|Open}}
{{agenda item|10:45a|Seminar prep}}
{{agenda item|11:00a|Seminar}}
{{agenda item|12:15p|Lunch: V&V?}}
{{agenda item|1:30p|Mani Chandy}}
{{agenda item|2:00p|Nok}}
{{agenda item|3:15p|Ling}}
{{agenda item|4:00p|Open}}
{{agenda item|4:45p|Open}}
{{agenda end}}
| width=50% |

==== Tuesday ====
{{agenda begin}}
{{agenda item|9:30a|Open}}
{{agenda item|10:15a|Open}}
{{agenda item|11:00a|Erik Winfree}}
{{agenda item|11:30p|Richard}}
{{agenda item|12:00p|Lunch: biocircuits?}}
{{agenda item|1:30p|Depart for airport}}
{{agenda end}}
|}

=== Abstract ===

TASK-INDUCED REDUCTION WITH APPLICATIONS TO NEEDLE STEERING

Vinutha Kallem<br>
Mechanical Engineering Department<br>
Johns Hopkins University<br>

Monday, April 28, 2008<br>
11:00 AM to 12:00 PM<br>
Steele Bldg. Room 114 (CDS Library)<br>

What if sensitive organs prevents a physician from accessing a percutaneous target using a straight, rigid needle? One promising solution involves steering flexible bevel-tip needles. These needles introduce exciting robotics and control systems challenges because the needle tip evolves on a Lie group, and the system exhibits a high degree of nonholonomy.

In this work, we present image-guided controllers for steerable needles to improve the accuracy of needle insertions. We build upon a previously proposed needle steering model to develop nonlinear observer-based controllers to drive the needle tip to a desired subspace. These controllers are designed to work in conjunction with subspace planners for the needle tip to reach a desired location in human tissue. We show that the tasks of these controllers induces symmetry, thus resulting in a reduced system which greatly simplifies controller and observer design. We propose a method to perform such reductions for generic nonholonomic kinematic systems on Lie groups with left-invariant vector fields. This technique is used to develop controllers for curve-following of a unicycle and subspace-following in needle steering. We show that this "task-induced" reduction lifts to mechanical systems.