Analysis On Puncture And Force Position Control System Of Vein Puncture Robot

As a common medical measure,intravenous puncture is used in blood collection,infusion and targeted treatment.In recent years,the intravenous puncture robot studied at home and abroad can perform the vein puncture instead of the medical doctors or nurses,and realizing the high efficiency and automation of the medical process.In current research process,the puncture simulation and experiment of blood vessels are mostly based on the single layer of blood vessel tissue,without considering the effect of the upper soft tissue on the blood vessel layer during the actual puncture process,and the force stability control is rarely considered when puncturing the biological soft tissue.Therefore,studying the blood vessel target area’s deformation which is squeezed by soft tissue such as skin,the path control and force position control of the robot.1.The displacement quantity of the puncture process based on the finite element dynamics is solved.Analyzing the process of needle puncture,and introducing finite element dynamics.Using MATLAB to establish and solve the finite element dynamics equations.Calculating the displacement of the target point,comparing it with the simulation results of Abaqus needle-vessel model dynamics,and verifying the accuracy of the finite element dynamics method.2.Simulation analysis of robot path control,motion control and soft tissue puncture.Firstly,vein puncture robot kinematics model according to D-H method is established,realized puncture robot path control in Cartesian space,and used trapezoidal speed planning to smooth robot start or stop stage.The path control effect and robot motion accuracy are verified through motion control experiment.Then,the needle-skin-vascular-muscle tissue model was established in Abaqus,conducted puncture simulation,analyzed the change law of puncture force which used to judge the stage of the current needle tip in the puncture process.The law that larger injection angle and needle speed can reduce the peak puncture force and improve the puncture effect is analyzed.Finally,according to the principle of vessel target area offset,the deformation amountof vessel target point is calculated by MATLAB analysis,and determined whether the current puncture path needs to be corrected according to the deformation amount.A correction method is given to ensure that the needle tip can puncture into the vessel target area more accurately.3.Studying on the impedance control algorithm of the vein puncture robot.The impedance control model of needle puncture vessel was established in MATLAB/Simulink,and the impedance control parameters were simulated.Adaptive impedance algorithm and self-tuning function are added to the impedance control in the puncture process respectively,and the results show that all three methods can realize the position tracking and force stability of the puncture process.However,compared to the classical impedance,after the mutation of the puncture object,the adaptive impedance algorithm reduces the steady-state response time from 8 seconds to 7 seconds,and the self-tuning function algorithm reduces the steady-state response time to 5 seconds.With the rectification function and coefficient,the method of adding self-tuning function makes impedance control better adjustment performance.4.Robot puncture analysis and impedance control experiment.Firstly,the three-dimensional force sensor is calibrated correctly.A linear relationship between the voltage signal output by the force sensor and the load force is obtained.Secondly,the experiment of puncture skin-vascular bionic model was completed to verify the faster needle speed and larger needle angle obtained from the Abaqus simulation results.Then,the puncture point target offset principle and the path correction method were experimentally verified.Finally,the impedance control hardware platform of the vein puncture robot was built to complete the impedance control experiment of the puncture process in the Vs environment,and adding the self-tuning function to compare with it.Experimental results verified the accuracy of the impedance control simulation results,and the position error after adding the self-tuning function decreased by 0.8mm.After the mutation of puncture object location,the adjustment time decreased from 6 seconds to 2 seconds,and improved the puncture effect.