Shape Sensing for Continuum Robots Based on MWCNTs-PDMS Flexible Resistive Strain Sensors

Abstract

Continuum robots show great potential in the medical field owing to their theoretically infinite degrees of freedom, but they still face challenges in shape sensing. This study focuses on shape sensing of continuum robots and designs a low-cost flexible resistive strain sensor based on multi-walled carbon nanotubes and polydimethylsiloxane. The sensor exhibits high linearity over the bending range of 0°-65° and offers 100% elongation at break and excellent mechanical properties, also showing good biocompatibility and environmental adaptability. A $3{\times }3$ array of these sensors is attached to the continuum surgical robot to realize shape sensing. The angle change of the continuum at each position is determined from the resistance change of each sensor during bending. The position information of five key points can be obtained from these angles, and the shape is reconstructed by fitting each point. Experimental results show that the proposed sensor can accurately sense various bending shapes of the continuum within the stable linear bending range, and the position error of the distal end fluctuates about 2% of the overall shape. This study provides a new solution for shape sensing of continuum surgical robots, demonstrating strong application potential.