Vinutha Kallem, April 2008

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



9:30a   Richard
10:00a   Julia
10:45a   Seminar prep
11:00a   Seminar
12:15p   Lunch: Nok et al
1:30p   Mani Chandy
2:00p   Nok
3:15p   Ling
4:00p   Elisa
4:45p   Sawyer


9:30a   Dionysios
10:15a   Shuo
11:00a   Erik Winfree
11:30p   Richard
12:00p   Lunch: Mary et al
1:30p   Depart for airport



Vinutha Kallem
Mechanical Engineering Department
Johns Hopkins University

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

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.