Design And Control Of Surgery Robot For Lung Cancer Puncture Guided By Magnetic Resonance Imaging

With the rapid development of robotics,the application of interventional robotics in the field of neurosurgery is becoming more and more mature.The minimally invasive surgery robot based on image navigation can improve the safety and therapeutic effect of surgery significantly.Most of the existing image navigation robots in China are based on CT.The identification of soft tissue is not as good as nuclear magnetic imaging.Most MRI puncture robots are still in the research and development stage,and most of the robots are only used for auxiliary positioning.The puncture process still needs to be performed manually.In this paper,the lung cancer puncture surgery robot guided by nuclear magnetic imaging is taken as the research object.For the spatial compatibility and nuclear magnetic compatibility in the nuclear magnetic scanning cabin under medical background,a series-parallel hybrid structure puncture surgical robot with compact structure and sufficient degree of freedom is designed.The control algorithm of the robot is studied.The robot adopts the pneumatic driving method.Therefore,the position control algorithm based on the hybrid fuzzy PID is designed mainly for the position of a single cylinder.In addition,the physical coordinates of the patient are registered with the reconstructed three-dimensional image coordinates of the MR scan image,and the follow-up and guidance of the surgical instruments are realized by registration.The specific work contents can be summarized as follows:Structural design and kinematic analysis of the robot.According to the working environment of the puncture robot,structural compatibility analysis and material compatibility analysis were carried out on the robot designed.The main material,sensor and driving method of the robot were selected according to the analysis results.At the same time,the five-degree-of-freedom robot structure based on series-parallel structure is designed,and the workspace is calculated by the Monte Carlo method.The working range of the tip meets the expected requirements.The modeling and analysis of the pneumatic system was carried out,and the control algorithm of the robot was proposed.The nonlinear system is linearized near the equilibrium position,and the flow continuity equation,the pressure flow equation of the proportional valve and the force balance equation of the cylinder piston are solved to obtain the third-order transfer function of the pneumatic system.Based on the analysis of the characteristics of traditional PID control algorithm and fuzzy control algorithm,combined with the medical background of robot,a hybrid fuzzy PID control algorithm is proposed and a fuzzy rule table of fuzzy controller is developed.The unit image coordinates and patient entity coordinates were registered using the unit four element method and the ICP algorithm.The feature points in the MRI image are identified and extracted,and the improved ICP algorithm is used to register the 3D model coordinates of the MRI image reconstruction with the patient entity coordinates,and the registration matrix and registration error are obtained,and according to the registration matrix.Achieve follow-up and guidance of surgical instruments.The simulation control and experimental research of the control algorithm are carried out,and the variable load experiments are carried out by different weights to verify the effectiveness of the composite fuzzy PID algorithm and the adaptability to the controlled model changes.At the same time,the robot is subjected to various pose adjustments to determine the positioning accuracy of the final puncture robot.