Design and Control of a Shape Memory Alloy Actuated Robotic Catheter

Abstract

This paper details the development of a Neural Network (NN) controller for a Shape Memory Alloy (SMA) actuated catheter, with potential application to tele-operated cardiac ablation procedures. The robotic catheter prototype consists of a central tubular structure actuated by four SMA tendons. A dual-camera imaging system provides position feedback of the catheter tip. Open loop bending responses are obtained and associated nonlinearities are identified. A NN controller is designed using time-shifted input-output maps generated from randomized open loop measurements. The tracking performance of this NN controller is compared with PI/PID controllers for various reference trajectories.

Design optimization of a shape memory alloy–actuated robotic catheter

“…The bending angle θ can be decoupled into θ xz (the bending angle projection in the XZ plane) and θ yz (the projection in the YZ plane). More details regarding this kinematic decoupling and its utilization in control synthesis are provided in Veeramani et al (2008b). Here, the goal is to model and optimize the planar design, resulting in optimal bending performance for each catheter segment.…”

“…This slack must first be recovered before the beam will bend in the antagonistic direction. Veeramani (2009) discusses the issues of antagonistic slack in greater detail.…”

Data-driven techniques to estimate parameters in the homogenized energy model for shape memory alloys

“…The super-elastic effect has been utilized in orthodontic wires, eye-glass frames, stents, and annuloplasty bands (Purser et al, 2009). Applications using the shape memory effect include robotic catheters (Veeramani et al, 2008a, 2008b), robotic hands (Price et al, 2007), jet chevrons (Hartl et al, 2010a, 2010b; Smith, 2005), and smart inhalers (Pausley and Seelecke, 2008). The design and control of these prototypes are complicated by the material’s nonlinear, hysteretic dependence on stress and temperature.…”