Executive Summary : | Magnetically actuated soft continuum robots (MSC robots) have drawn significant attention for minimally invasive cardiovascular surgery. Once the MSC robot is inserted into the desired location in a blood vessel, it takes a curved configuration depending on the location of surgery. Under external magnetic actuation, effect of the initial curvature on the active steering of the HMS portion becomes significant which is not considered in the existing models. In addition, the interactive combined effect of the distributed load coming from the flowing blood with the cutting force required for surgery and the external magnetic field is also not considered. As MSC robot is made of a very soft material having very low stiffness, delivery of the required force for operating the blood clots along with withstanding the operating force and pressure of the flowing blood by the rest portion of the MSC robot becomes questionable. Thus, there exists a strong rationale for optimized design of a novel MSC robot considering all the mentioned complicating effects. In the present work, a novel magnetic soft continuum robot named NHMSC robot with two different magnetically active portions having initial curvature under the controlled external magnetic field combined with the mechanical forces coming from surgery and flowing blood is proposed with actively controlled workspace and modulated stiffness. The project aims to develop a semi-analytical framework to analyse multi-physical mechanics of the proposed novel NHMSC robot. The two magnetically active parts of the NHMSC robot will be modelled as large deforming HMS curved beams subjected to compound effect of initial curvature and magneto-elastic coupling in addition to complex boundary conditions due to kinematic constraints. Variational energy principle will be employed to derive governing equation along with a numerical scheme for the nonlinear computational framework. A finite element model will be developed to validate the proposed semi-analytical framework. Within the developed physically insightful framework, modulation of stiffness of the magnetically active parts and active control of the workspace of the NHMSC robot to supply and withstand the forces required for surgery and flowing blood will be performed. Based on the modulation and active control studies, optimized design of the novel NHMSC robot in terms of optimized hard magnetic particle distributions under a controlled external magnetic field will be proposed employing an efficient optimization algorithm. The proposed generic novel parameters introduce novel exploitable dimensions into the foundational research on MSC robots. Treatments of the multi-physics problem in a semi-analytical manner will provide adequate physical insights, leading towards their potential uses for analysing other complex multi-physics problems. The proposed optimized design of the novel NHMSC robot would be efficient for precise minimally invasive cardiovascular surgery. |