RESUMEN
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.
Asunto(s)
Agujas , Instrumentos Quirúrgicos , Algoritmos , Fenómenos Biomecánicos , Biopsia , Simulación por Computador , Humanos , Fantasmas de Imagen , RobóticaRESUMEN
This paper deals with the development of a coordinated control system for a robot and robot-driven shape memory alloy (SMA) actuated needle to follow a curvilinear path for percutaneous intervention. The robot driving the needle is considered as the outer loop and the non-linear SMA actuated flexible needle system forms the inner loop. The two feedback control loops are coordinated in such a way that the robot drives the needle considering the needle's actual deflection so that the needle tip reaches the target location with an acceptable accuracy. Simulation results are presented to verify the efficacy of the controller for tracking the overall desired trajectory which includes the combined trajectory of the robot and the needle.
Asunto(s)
Aleaciones/química , Braquiterapia/instrumentación , Próstata/efectos de la radiación , Robótica/instrumentación , Humanos , Masculino , AgujasRESUMEN
In robot-assisted needle-based medical procedures, path planning for a flexible needle is challenging with regard to time consumption and searching robustness for the solution due to the nonholonomic motion of the needle tip and the presence of anatomic obstacles and sensitive organs in the intended needle path. We propose a novel and fast path planning algorithm for a robot-assisted active flexible needle. The algorithm is based on Rapidly-Exploring Random Trees combined with reachability-guided strategy and greedy heuristic strategy. Linear segments are taken into consideration to the paths, and insertion orientations are relaxed by the introduction of the linear segments. The proposed algorithm yields superior results as compared to the commonly used algorithm in terms of computational speed, form of path and robustness of searching ability, which potentially can make it suitable for the real-time intraoperative planning for clinical procedures.