Elastic Stability of Concentric Tube Robots Subject to External Loads

Equilibrium Conformations of Concentric-tube Continuum Robots

Robots consisting of several concentric, preshaped, elastic tubes can work dexterously in narrow, constrained, and/or winding spaces, as are commonly found in minimally invasive surgery. Previous models of these "active cannulas" assume piecewise constant precurvature of component tubes and neglect torsion in curved sections of the device. In this paper we develop a new coordinate-free energy f...

Interactive Motion Planning for Concentric Tube Robots

Concentric tube robots may enable new, safer minimally invasive surgical procedures by taking curved paths to difficult-to-reach areas of a patient’s anatomy. Operating these devices is hard due to their complex and unintuitive kinematics. Existing position control methods for driving the robot’s tip can cause the robot to collide with sensitive structures in the anatomy associated with patient...

Concentric Tube Robots for Minimally Invasive Surgery

INTRODUCTION The human body was not designed to facilitate surgical repair. Thus, in order to minimize collateral damage to healthy tissue, many interventions require following complex curved paths through tissue and body lumens to reach surgical targets. The smallest existing instrument technologies utilizing this approach are comprised of catheters and endoscopes for passing through body lume...

Concentric Tube Robots for Transurethral Prostate Surgery: Matching the Workspace to the Endoscopic Field of View

INTRODUCTION Transurethral laser surgery using a flexible multibackbone robot was recently demonstrated by Simaan et al. for bladder resection [1]. For transurethral prostate resection, thinner flexible manipulators are desirable. We have developed a hand-held system that transurethrally deploys two concentric tube robots through an 8.3 mm diameter rigid endoscope [2], as shown in Figs. 1 and 2...

Nonlinear axisymmetric deformations of an elastic tube under external pressure