Characterization and modelling of carbon black nanocomposite strain sensor on pneumatic driven flexible catheter for pulmonary surgery robots

Abstract

• Constructed a pneumatic drive system for a 4 mm catheter, achieving bending angles of up to 65°. • Developed a carbon black strain sensor with a minimum detectable strain of 0.44% and a response time of 0.5 s. • Improved bending angle prediction accuracy by correcting calculations based on strain sensor data. The pulmonary surgery robot is equipped with a flexible catheter designed to navigate narrow bronchi and perform precise surgical operations on lesions, offering benefits such as minimal invasiveness and high flexibility. This study focuses on the shape control and strain sensing of the catheter’s tip. A gas-driven control platform was developed for a three-channel catheter, incorporating miniaturized precision valves to enhance the accuracy of pneumatic pressure control. Concurrently, ultra-thin flexible strain sensors were fabricated using PDMS and carbon black to detect bending strain, and their sensing performance was assessed to identify optimal fabrication parameters. Finally, the control platform and strain sensors were integrated to validate the system’s capability to manage the catheter’s bending shape while simultaneously sensing its deformation. This integration provides a theoretical foundation for enhancing the precision and safety of catheters in practical applications of surgical robots.