Error Analysis And Path Planning Of Flexible Needle Insertion Into Soft Tissue

With the development of minimally invasive surgery,the puncture needle,as the most basic minimally invasive instrument for minimally invasive surgery,has gained considerable attention in medical applications such as in vivo physical examination,interventional radiation,and local anesthesia.However,in the puncture process of beveled flexible needle,due to the influence of human physiological movement,natural breathing,the targets and obstacles of puncture soft tissue environment will also move correspondingly.However,due to the influence of human physiological movement and natural respiration during the puncture of the beveled flexible needle,the puncture target of the flexible needle and the obstacles such as blood vessels in the punctured soft tissue environment will also change accordingly.Therefore,it is very important to plan the puncture path and improve the accuracy of flexible needle insertion into the target.In view of the above problems,this paper proposes the path planning and error analysis of flexible needle insertion into soft tissue,establishes a prediction path of flexible needle based on Fokker-Planck equation and Disjunctive Kriging,and finally realizes the research of the flexible needle accurately puncturing the soft tissue to the target point in a nonlinear environment.Firstly,the bending motion characteristic of the flexible puncture needle during the puncture process can be approximated as a circular arc motion with a fixed radius r,the D-H(Denavit-Hartenberg)parameter method is used to establish the forward puncture motion model of the beveled flexible needle based on the characteristic.The flexible needle system is divided into a linear part and a nonlinear part.The linear part uses the Kalman filter to estimate the linear system model,and the nonlinear part uses the Taylor formula to linearize the nonlinear model as a controller.The control input required to reach the target point is inferred by the kinematic model of the robot,and the Kalman filter is designed to estimate the specific parameters of the model,so as to obtain a more accurate soft tissue model of flexible needle puncture.Secondly,by analyzing the interaction force during the soft tissue puncture movement of the flexible needle,the trajectory planning of the needle tip during the puncture movement of the flexible needle and the puncture error during the movement process are studied,so as to provide a theoretical basis for the subsequent path planning problem of the flexible needle puncturing the soft tissue.The model of the friction force and cutting force of flexible needle puncture is established,and this model combined with the artificial potential field deduction formulas,the error size in the process is judged,and the force model of puncture is continuously optimized to achieve the purpose of optimal control of the force on the needle tip.Finally,in view of the uncertainty,nonlinearity and anisotropy of the puncture environment in the soft tissue with flexible needle,in order to more generally approach the actual medical application environment,a probabilistic path and Disjunctive Kriging algorithm are used to analyze the puncture process.By continuously optimizing the relevant data parameters in the model such as the mean and variance during the puncture process,optimizing the puncture model,and evaluating and improving the error parameters to reduce the puncture error,and finally realizing the research of the flexible needle accurately puncturing the soft tissue to the target point in a nonlinear environment.