Shape Sensing Method of Discrete-Jointed Continuum of Narrow Auditory Meatus Based on FBG Sensing

Injection and sampling of inner ear lymphatic fluid through auditory meatus is an innovative procedure in otology. The urgent need for precision surgery further motivates the application of continuum robots. The tradeoff between confined working space and high precision shape sensing that can intelligently avoid critical anatomy poses a major challenge. In this article, we study an error compensation method of continuum robot shape sensing based on fiber Bragg grating (FBG). The FBG sensing array is integrated with the extremely short continuum. Further, we present a dynamic shape sensing method for otology continuum robot based on FBG and conducted dynamic experiments on models to simulate the injection progress. The percentage error on the planar C-shaped model is 3.32%. On the planar S-shaped models, the percentage error reduces from 6.25% to 5.86% with the decrease in the channel diameter. An experimental shape sensing system of the otology continuum robot is built. The standard deviation of shape sensing is 0.6185–1.6638 mm. An innovative detection method is proposed for the shape sensing of continuum in narrow spaces. The experimental results with an average error of 1.2163 mm effectively verify the feasibility of continuum shape sensing in narrow channels based on FBG.