Magnetic Trackers: Robot Control and Vasculature Imaging - Microsurgery: Advances, Simulations, and Applications - page 241

regions (Fig. 7.12(b)). Five spatial points were collected during
that time. Each collected point was associated with a ( C a 0 n , C a 1 n , C a 2 n ,
C a 3 n ) coniguration of the ACIS. The sparse LUT M 1 only modiies the
parameter C a 1 n to change the speed of the catheter insertion. This
makes that the catheter trajectory is only modiied by the lumen
of the silicone model and changes in catheter speed. d n was set to
20 mm in all reference points, as this is the maximum cross section
diameter of the silicone model of vasculature. The magnetic tracker
was placed inside the LSM and taken to the entrance of the arterial
block model. From the software of the PC the LSM unit and magnetic
tracker console were initialized and the feedback system was
activated. The system compares then the actual position of catheter
with every point of the map using Eq. 7.3. Using this strategy, the
ACIS changed LSM's speed along the silicone block model according
to M 1 .
During the path reconstruction in this coniguration, the system
changed LSM's catheter insertion speed as speciied on M 1 (Fig.
7.16), on a maximum radius of 24.5 mm from each reference point
when the speciied range was 20 mm. An erratic behavior appeared
between P a 0 and P a 1 , as their detection range intersected. The system
alternated between both deined conigurations in this part of the
simulation. This phenomena is not desirable as the robot must be
guided properly.

80

Magnetic Sensor Trajectory

Reference point

60

LSM Motion Reconfigured

40

20

0 40 80 120 160 200

Coronal axis (mm )

Figure 7.16 Projection of magnetic sensor trajectory during insertion by
LSM in arterial block model with reference map feedback.