Design and Hysteresis Compensation of a Telerobotic System for Transesophageal Echocardiography

Transesophageal echocardiogram (TEE) plays an important role in diagnosing cardiac conditions such as valvular diseases and cardiac embolism, as well as guiding various cardiac interventions. It provides detailed cardiac imaging by inserting a probe into the esophagus, which offers an unobstructed view of the heart's chambers and valves. Addressing the operational challenges and health risks of the sonographer associated with the manual procedure, a novel robotic TEE system is developed to teleoperate the TEE probe across all four degrees of freedom (4-DoFs). This actuation device features an easily assembled design for post-operative cleaning and sanitization. Moreover, this system enhances the precision of tip bending angles through an optimization technique for offline calibration of the actuation plane. The hysteresis effect inherent in the tendon-driven mechanism is characterized and compensated using a free knots B-spline method and a look-up table. Experiments are conducted in a realistic human cardiovascular phantom for preclinical evaluation. Repeatability experiments validate the system's robustness. Furthermore, compared with the piecewise linear model, the proposed method achieves high accuracy with a median bending angle error of less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {0.8^\circ }$</tex-math></inline-formula>. The results demonstrate the system's potential to significantly improve the autonomy of TEE procedures in cardiac diagnostic and therapeutic procedures.