DESIGN DEVELOPMENT AND CONTROL OF MINIATURE ROBOT FOR IN-VIVO BIOPSY

Abstract

The introduction of robot-assisted minimally invasive techniques to general surgery, for performing biopsy and abdominal cavity exploration has been described as one of the most significant changes in the history of surgery since the introduction of anaesthesia. Biopsy in the stomach is required to identify gastric cancer, polyps etc. The adoption of robot-assisted minimally invasive surgery techniques has significantly reduced patient’s discomforts. Integration of robot hardware with computer-integrated surgical systems has the potential to enable precise, targeted, minimally invasive medical interventions and enhance the effectiveness of clinical procedures. The trend of modern research in the area of in- vivo robots are aimed at making robotic devices smaller, safer and image compliant and also adding intelligence to robotic surgical devices by tackling the issues of motion uncertainty, healthy tissue deformation. The challenges associated with in-vivo robot are, compromised dexterity, limited visibility for surgeon to perform task, insufficient mobility, limited degrees of freedom (DOF), and limited maneuverability. Therefore there is a need of a miniature in- vivo robot as an exploration tool which can be easily controlled, and has high mobility. The main aspects of the miniature in-vivo robot namely proper design of the in-vivo robot with better dexterity while taking biopsy sample inside stomach model, forward and inverse kinematics of the designed in-vivo robot, trajectory and force control were identified as the main areas of study in this thesis. A proper design of the in-vivo robot was prepared in Solid Works after conceptualizing the design. Forward and inverse kinematic analysis were performed to obtain the transformer modulli for developing the bond graph model. A wire actuation mechanism was simulated in bond graph and incorporated in the physical system for in-vivo robot joint actuation. A virtual link based controller was developed keeping in view of the dynamic equivalence of the in-vivo robot and its competence was tested in simulated invironment using bond graph technique. Further a hybrid trajectory/force control strategy was developed keeping in mind to attain the desired trajectory without any harm to the healthy tissues inside the abdominal cavity. It’s competence was tested in simulated environment.