| Lung puncture surgery has the characteristics of little trauma and quick recovery,flexible operation,wide application and so on.It is a kind of the minimally invasive surgery.However,during the surgery,the doctor has to complet the puncturing operation with bare hands.On the one hand,because of the inability to see the needle tip in real time and the radiation in the operation,it is necessary to perform multiple blind operation by step.On the other hand,the most frequently used puncture needle in the operation will have significant bending deformation during the injection process,and can not follow the straight line path designed from the needle point to the target,which increases the difficulty of the hand operation control.Adopting robot technology and depending on operation robot to control puncture instrument can replace doctor's hand operation.The effective control method is adopted to improve the stability,safety and controllability of the operation process.It is an effective means to improve the effect and quality of the lung puncture operation.With the background of lung puncture surgery,this paper aims at the shortcomings of traditional pulmonary puncture and the clinical needs of the robot in the operation.The research on the target drift caused by respiratory movement,the mechanical interaction mechanism of needle and soft tissue,the apperception of the tip deviation of the flexible needle,the path planning of the needle and the control method and so on are carried out in this paper.By breaking through the key problems,such as the measurement and prediction of aspiration,the interaction mechanism of needle-soft tissue,the position measurement of needle tip and the path planning of the surgery,this paper can provide the theoretical basis and experimental data support for the application of the robot assisted lung puncture.The main contents of this paper are as follows:(1)Research on the robot system of lung puncture surgery.According to the traditional pulmonary puncture procedure and the existing problems,the environment and space restriction of the lung puncture operation were analyzed,the mechanical structure and control system of the lung puncture operation robot were studied.A kind of lightweight,CT compatible robot system for lung puncture was developed,and the operation procedure suitable for the human assisted puncture was developed.(2)Study on collection and prediction of respiratory movement and solve the problem"when to puncture".Collect and analyze the data of respiratory movement,and divide it into three stages.According to the respiratory movement correlation model,using respiratory gating to guide the robot to puncture at the end of the expiratory stage.Nonparametric regression method is used to predict respiratory movemengt,compensate for the delay of the acquisition device,and inform the doctor when to perform puncturing.(3)Research on the mechanics interaction between needle and soft tissue and position perception of the needle tip.The force characteristics of the needle are analyzed,the mechanical model of the puncture needle is established,and the method of measuring the tip offset based on the force perception is put forward.The feasibility and accuracy of the methods are verified by the experiments.The tip migration based on the kinematic model is studied,and the method of measuring the key parameters of the "wheelbarrow" model based on the force perception is proposed,which lays the foundation for the trajectory planning.(4)Path planning and control of the needle.According to the "wheelbarrow" model,the path planning of needle puncture needle is studied,and it is extended to three dimensional space.At the same time,Rapid-exploration Random Tree is improved and used in the flexible needle path planning.A path evaluation function based on path length,distance from obstacles and number of needle transfers is proposed and the optimal path is selected.The feasibility of the algorithm is verified by simulations,which can provide the basis for subsequent experiments.(5)Experimental study.The key parameter of the "wheelbarrow" model is obtained through force perception,and the measurement accuracy of the method is verified.An obstacle avoidance experiment was carried out to verify the precision and effect of trajectory planning control of puncture needle.The positioning accuracy of the robot is measured,and the puncture accuracy and planning effect are verified by the model experiment.Finally,the model experiment under CT is carried out to verify the feasibility of the puncture robot and its compatibility with CT,which lays a technical foundation for the further practical work. |
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