0
Research Papers

Design of Underactuated Steerable Electrode Arrays for Optimal Insertions

[+] Author and Article Information
Jian Zhang

e-mail: jz2181@columbia.edu

Nabil Simaan

e-mail: nabil.simaan@vanderbilt.edu
Advanced Robotics and Mechanisms
Applications Lab (ARMA Lab),
Department of Mechanical Engineering,
Vanderbilt University,
Nashville, TN 37235

1Corresponding author.

Contributed by the Mechanisms and Robotics Committee of ASME for publication in the Journal of Mechanisms and Robotics. Manuscript received March 7, 2011; final manuscript received April 25, 2012; published online January 24, 2013. Assoc. Editor: Anupam Saxena.

J. Mechanisms Robotics 5(1), 011008 (Jan 24, 2013) (11 pages) Paper No: JMR-11-1029; doi: 10.1115/1.4007005 History: Received March 07, 2011; Revised April 25, 2012

This paper addresses the design of wire actuated steerable electrode arrays for optimal insertions in cochlear implant surgery. These underactuated electrode arrays are treated as continuum robots which have an embedded actuation strand inside their flexible medium. By pulling on the actuation strand, an electrode array assumes a minimum-energy shape. The problems of designing optimal actuation strand placement are addressed in this paper. Based on the elastic modeling of the steerable electrode arrays proposed in this paper, an analytical solution of the strand placement is solved to minimize the shape discrepancy between a bent electrode array and a given target curve defined by the anatomy. Using the solved strand placement inside the steerable electrode array, an optimized insertion path planning with robotic assistance is proposed to execute the insertion process. Later, an optimization algorithm is presented to minimize the shape discrepancy between an inserted electrode array and a given target curve during the whole insertion process. Simulations show a steerable electrode array bending using the elastic model and robot insertion path planning with optimized strand placement. Two experiments have been conducted to validate the elastic model and algorithms.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Insertion of electrode arrays into the scala tympani

Grahic Jump Location
Fig. 2

(a) Top and side view of the steerable electrode array with embedded strand, (b) bent shapes of the steerable electrode array

Grahic Jump Location
Fig. 3

Geometric modeling of the steerable electrode array in initial straight configuration with segment i highlighted

Grahic Jump Location
Fig. 4

Static modeling of the steerable electrode array at layer i

Grahic Jump Location
Fig. 5

(a) Target curve, (b) segmented target curve, and (c) local coordinate systems of the bent steerable electrode array

Grahic Jump Location
Fig. 6

Overlay of z images (a) taken from calibration process and (b) simulated virtual calibration images using elastic model

Grahic Jump Location
Fig. 7

Schematics of 4 DoF robot with optimization parameters

Grahic Jump Location
Fig. 8

A strand placement using kth order polynomial expression

Grahic Jump Location
Fig. 9

Flow chart of optimization algorithm

Grahic Jump Location
Fig. 10

Detailed flow chart of virtual calibration module

Grahic Jump Location
Fig. 11

Detailed flow chart of insertion simulation module

Grahic Jump Location
Fig. 12

(a) An arbitrary given strand placement and (b) bent shapes of the steerable electrode array with the strand placement in (a)

Grahic Jump Location
Fig. 13

(a) Solved strand placement from analytical solution and (b) smoothed strand placement based on (a)

Grahic Jump Location
Fig. 14

Modified target curve with simulated bent electrode shapes (a) using unsmoothed strand placement in Fig. 13(a) and (b) using smoothed strand placement in Fig. 13(b)

Grahic Jump Location
Fig. 15

Simulation using unsmoothed analytical solution of strand placement

Grahic Jump Location
Fig. 16

Optimization algorithm results (a) linear strand placement and (b) nonlinear strand placement

Grahic Jump Location
Fig. 17

Comparison of four insertion simulation results, AS, analytical solution; OA, optimization algorithm; SP, strand placement

Grahic Jump Location
Fig. 18

Selection of initial conditions for global search

Grahic Jump Location
Fig. 19

Overlay of simulation results onto bent electrode arrays

Grahic Jump Location
Fig. 20

Simulated bent electrode shapes with error bounds (a) ±5% modeled internal friction, (b) ±5% measured Young's modulus. (c) Simulated bent electrode shapes with ±1 (±21%) pixel segmentation error bounds.

Grahic Jump Location
Fig. 21

Segmentation of fabricated electrode array with designed strand placement (a) raw image, (b) BW image, and (c) segmented image

Grahic Jump Location
Fig. 22

(a) Experimental setup, (b) 6-DoF F/T sensor, (c) parallel robot with strand actuation motor and F/T sensor coordinate systems, and (d) scaled-up target curve model

Grahic Jump Location
Fig. 23

Comparison of insertion images using (a) 1 DoF nonsteerable (straight) electrode and (b) 4 DoF steerable electrode

Grahic Jump Location
Fig. 24

Comparison of insertion forces using (a) 1 DoF nonsteerable (straight) electrode and (b) 4 DoF steerable electrode

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In