Robot Assisted Suturing using Virtual Fixtures
THE PROBLEM
  1.  Endoscopic surgery presents a constrained working environment for surgeons
  2.  Surgeons must deal with realities of long instruments and awkward angle
  3.  Suturing is probably the most difficult and time consuming of all MIS tasks
THE SOLUTION
Decompose the task into simpler substeps
  1. Align Step
  2. Aim is to ensure needle is aligned correctly before and after puncture
  3. Composed of four substeps, numbered 1-4.
  4. Bite Step
  5. Ideal trajectory is a circle with radius equal to needle radius
  6. This step is formulated as substep 5.
Use Constraint Control Algorithm to provide augmentation for each substep.
THE RESULTS
Complex tasks such as suturing are decomposed into sequences of constrained motions steps.
Each motion step is constructed from one or more primitive “virtual fixtures” (VF).
Suturing task using VF showed significant  improvement in performance over freehand.
  1. Can be performed at awkward angles
  2. Avoids multiple trials and large undesirable movements inside tissue.
PUBLICATIONS
Spatial Motion Constraints for Robot Assisted Suturing using Virtual Fixtures, MICCAI, 2005.
Suturing in Confined Spaces: Constrained Motion Control of a Hybrid 8-DoF Robot, ICAR, 2005