The Studies On Tactile Feedback-based Minimally Invasive Cardiac Surgery Robotics

During minimally invasive surgery, due to the limited operating space and indirectaccess to information, the doctors will lose a lot of tactile information, which can easily leadto misuse and increased surgical risk. The emergence of Auxiliary Medical Robotssignificantly improves the accuracy and reliability of the doctors’ surgery operation, and hasgreat significance to the development of medical standards. Therefore, the study of minimallyinvasive surgical robot and its key technologies get more and more attention.The minimally invasive surgical robot is a remote operating system which is mainly bymeans of the virtual sensor technology and then reproduce the force/tactile sense of realityof the operative slave side in the master side by the tactile feedback device. By the end of theimage information acquired from the slave side, computer reconstruct local three-dimensionalmodel of the surgical object frequently, thereby obtaining tactile information (size) of theforce feedback, and then passed it to the operator’s hand via a tactile feedback device. Thereare two main work of this paper, one is medical image segmentation technology, which is thebasis for3D medical image reconstruction; the second is tactile generated reproductiontechnology, which is the key to get tactile feedback information to characterize the surgicalobject properties for operator. Around these two parts, the main work content for this paper:(1) Research on medical image segmentation techniques based on level set algorithm.Based on the active contour level set algorithm, image segmentation techniques have theadvantages of dealing with boundary topology changes naturally, getting stable numericalsolution, and being suitable for any number of dimensions, etc. Particularly appropriate forhuman body structure anatomical images with complex and varied structure and closedcontour curves of various tissues and organs. In this paper, a multi-threshold single level setalgorithm based on the CV model is used and application of Li Chunming penalty is appliedto improve its factor, to achieve a fast and accurate segmentation of medical images.(2)Research on flexible body deformation model. In the process of interaction with thevirtual environment, in order to obtain realistic tactile feel, suitable deformation model andthe force sense generation algorithm is essential. In this paper, based on the physicalsignificance, a concentric circles segmentation method spring-mass model is used inmodeling the heart organ deformation, which can accurately express the physics andkinematic characteristics of the heart organ, and can get realistic deformation effects and tactile feel.(3)Research on collision detection technology. Collision detection is an essential link inthe virtual reality, and is an important means to ensure the operation of authenticity andsecurity. In this paper, using k-DOP hierarchical tree based on balanced binary achievecollision detection between the virtual objects, and updating k-DOP tree in real time when theobjects are moving or deforming increase the fidelity of the simulation.Finally, the heart minimally invasive surgical platform is set up based on the aboveresearch, do some experimental evaluation of the theoretical research on the platform toverify its feasibility and operability.