Wave variables based bilateral teleoperation of an active catheter

In this paper, we develop a teleoperation framework to perform master-slave control of an active catheter instrumented with Shape Memory Alloy (SMA) actuators. The catheter is also instrumented with a 5-DOF magnetic sensor which provides feedback on the position of the distal end of the catheter while strain gauges on the catheter tip reflect the forces. SMAs demonstrate a hysteretic, non-linear and time-delayed behavior; therefore maintaining stability of the teleoperation algorithm is a prime requirement. The wave variables based approach provides a robust method to perform bilateral teleoperation of the active catheter. The clinician controls the position of the tip of the catheter from a remote location while precisely feeling the forces acting on the catheter tip. This enables the clinician to perform fine manipulations within the blood vessels, close to bifurcations and to the site of plaque buildup. In addition, a force control algorithm has been developed and implemented on the active catheter for enabling smooth guidance of the catheter into the vasculature and for application in cardiac ablation. Experimental results are presented for the proposed algorithms.