Study On Control Method Of Robot In Tumor Puncture

The puncture of tumor plays an important role in the minimally invasive interventional treatment of tumor,the accuracy of the puncture affects the quality of follow-up surgery directly.At present,the puncture operation in clinical is generally performed manually by a doctor or with the help of a guide device,and there is no device that can assist the doctor in performing the puncture operation.As a result,the surgical results are highly dependent on the experience and the patient’s cooperation.The accuracy is not stable,and it is difficult to meet the requirements of some clinical interventional therapies,such as the nano-knife with high requirements on the parallelism of the needle.It also increases the fatigue of doctors and the radiation damage for patients.In order to make up for existing shortages in manual puncture,a highly automated device is necessary to be designed to perform accurate puncture operation under the control of a doctor.For this reason,a robot assisted system was constructed to assist the doctor in completing the tumor puncture by using a robot with high-precision linear motion,combining an optical navigation device for real-time tracking and positioning,and associating a software planning module for puncture solution.The problems just as the existing end gripper cannot firmly hold the puncture needle and so on need to be solved to complete the implementation of the puncturing operation for a robot.And to work out the hand-eye and tool-flange calibrations to bridge the navigation and positioning device,the robotic arm and the puncture needle.Base on the calibration outcome,the relationship between different frames in the system should be calculated,and to obtain the command of entry point,target point,and puncture angle.Finally control the robot to complete the tumor puncture operation.For the above issues,this article completes the corresponding research content:(1)A robot system was constructed for assisted tumor puncture.The hardware platform of the system consists of a UR10 robot with appropriate parameters,an optical navigation and positioning device,a new holder designed,and a puncture needle.The software platform of the system is mainly composed of the puncture path planning module,which combines the preoperative imaging and the tracking of the optical navigation to complete the path planning.Then the planning outcome is fed to the robot to obtain the robot control command by combining the coordinate conversion relationship.Finally,the effectiveness of the system was confirmed by the head model and other experiments.(2)A rapid calibration method suitable for clinical use was studied.Based on two basic mathematical matrix transformation calculation methods,the Rodriguez rotation formula and the matrix pseudoinverse,a highly practical calibration method based on three-circuit calculation was proposed.By using this method,the hand-eye calibration and tool-flange calibration of the robot can be realized.The final simulation and actual experimental results show that hand-eye calibration and tool-flange calibration can be accomplished through 13 pose data,and the calibration error was within 5 mm.This method combines the robot motion and can accomplish calculations based on less data while achieving a predetermined higher calibration accuracy,which meets the needs of clinical high-precision and rapid calibration applications.(3)The robot’s puncture control method was studied.Based on the calibration outcome,the unknown transformation matrixes between different frames in the system can be calculated,and then the coordinate in the optical navigation device frame can be converted to the robot base frame.In this way,the entry point and the target point were obtained,and the puncture needle set angle was further obtained.Finally,the experiments of point accuracy and trajectory accuracy show that the control precision of the auxiliary puncturing system constructed in this paper is less than 5 mm.In this article,a universal surgical robot end holder for percutaneous puncture was designed for the implementation of the puncturing action,with the help of linear motion of the robot.Based on a robotic arm,a robotic system for tumor puncture was constructed in combination with an optical navigation and positioning device.A calibration method based on three-loop calculations was proposed.By using this method,high-precision hand-eye and toolflange calibrations can be accomplished based on a small amount of data and basic algorithms.The problem of control parameter calculation and the robot control was solved.Finally,it was verified through experiments that the assisted puncture robot constructed in this paper can effectively reduce the preparation time for puncture surgery,and can accurately implement the puncture action.And it reduce the burden on the doctor,reduce the radiation damage to the patient,and reduce the risk of puncture surgery complications.And it is also shows the robot constructed is suitable for the application of clinical common puncture surgery and has a good application prospect.