Control of a flexible bevel-tipped needle using super-twisting controller based sliding mode observer

This article presents the implementation of super twisting controller based on higher-order sliding mode observer during needle maneuverability in minimal invasive surgery. To ensure chattering free and stable maneuverability of the needle in spite of external disturbances, a robust control strategy is necessary. Technically, it is cumbersome to develop the structure of super twisting controller with a third-order sliding mode observer leading to discontinuous control law. Henceforth, we propose the higher order (n+1) sliding mode observer with continuous control law. Our study involves the kinematic model of the bevel-tipped flexible needle to inculcate an accurate target reaching regulation of the needling system. Both simulation and experimental results with various bevel angles are presented to verify the proposed needle steering control methodology in biological tissue environment.