Medical Tele-operation Robot System Modeling And Analytical Research

In the current field of application for medical robot, teleoperation robot puncturesurgery becomes a focus of research. There often lead to deviation between actual punctureposition and goal targets in the process of piercing due to deformation of puncture needleand soft tissue. In order to reduce communication delay and improve tracking effect ofposition and force, the vast majority of research on network communication and local areanetwork teleoperation, therefore ignore deflection caused by puncture needle curve intele-puncture operation. There are lacking of quantitative deformation analysis of soft tissueapplied force and fundamental research of tip trajectory planning in piercing operation.This paper analysis and study the problems mentioned above. The main research worksare as follows:Firstly, In order to reduce deflection of the puncture needle and increase the accuracyof the robot-assisted needle insertion into soft tissue, the physical model of puncture needleis built with elastic cantilever beam. The algorithm is proposed to analyze force added onpuncture needle and obtain the deflection and angle of element node. The theoreticalcalculation and experimental simulation results show the validation and consistency of thealgorithm.Secondiy, In order to obtain relationship between deformation size and force, dynamicprocess of the soft tissue deformation during needle insertion is decomposed into series ofdiscrete quasi-static stages. Every note’s displacement and force distribution of the softtissue is acquired by simulating needle insertion into two and three dimensional tissue. Thesimulation results show that deformation is proportional to the force; step-by-step loadeffect is agreed with combined action.Thirdly, In order to get tip trajectory of puncture needle, piercing process isdecomposed into a set of discrete quasi-static process. Getting tip trajectory by calculatingneedle tip coordinate at every moment, in which coupling of needle deformation, punctureangle and needle base vertical coordinate are considered. The simulation results showed thatthe elastic deformation of puncture needle does not affect needle tip trajectory evidently, andthe main factors of effects on needle tip trajectory are the puncture needle verticalcoordinate and initial puncture angle.Finally, In order to carry out needle insertion into soft tissue experiment, improving original SDOF teleoperation experimental system, and designing the controller ofMaster-Slave hands. The simulation results show the validation of the controller. TheLabVIEW platform of the system is established for data acquisition, serial portcommunication, network communication and verifying the validation of sliding modecontroller. The experiment result showed that the system realized the position and forcetracking.