This thesis introduces the study of intrinsic force sensing for steerable catheters based on the physical modelling and shape analysis of a catheter, without a physical force sensor to reduce the complexity of the device design and system integration. Furthermore, a model-free position/force controller has been developed to use the estimated interaction force as feedback to regulate the magnitude and direction of the applied force to a tissue by the catheter. The research introduced in this thesis is in the following order. First, a linearly actuated catheter robot with tension sensors has been developed to steer the catheter based on the tension feedback. Two intrinsic force sensing methods have also been developed and validated based on shape tracking of a catheter. The first method is based on using shape analysis to estimate the multiple contact forces along the catheter during catheter insertion, normally under fluoroscopy imaging. The second method has been developed to estimate 3D contact forces using bi-point tracking on the catheter and tension feedback. Moreover, a modelfree control approach is proposed for controlling the position and contact force of the catheter tip to generate a desired contact force during ablation of a location using the estimated contact force and the tendon tension as feedback. The intended application of this study is the cardiac ablation for treating arrhythmia, in which the applied contact force during ablation is highly correlated with the procedure outcome. In addition, the methods developed from this study are also applicable for the force sensing and interaction control for other tendon driven catheters.
Intrinsic force sensing and interaction control for cardiac catheters
Back, J. (Author). 1 Dec 2017
Student thesis: Doctoral Thesis › Doctor of Philosophy