Research On Key Technology Of Radioactive Seed Implantation Robot For Prostate

As a result of the surgery of good targetability, small trauma, quick curative effect, less side effects, seed implantation brachytherapy has become the standard treatment method for early prostate cancer. The use of robotic system to assist doctors in performing the surgical treatment, can improve the accuracy of seed implantation, enhance the patient's treatment effect, reduce the surgeon labor intensity, reduce infection and improve radiation. Research and develop a prostate seed implantation robot system with independent property rights, low cost and high performance, it not only has high academic value, at the same time is conducive to the technology in domestic clinical application and popularization. However, the successful use of robotic systems in radioactive seed implantation surgery for prostate cancer requires solve the robot configuration and size optimization, the robot control accuracy and motion stability, high precision and efficiency of puncture and other issues. In order to solve the above problems, this paper in-depth study on key technology about a radioactive seed implantation robot for prostate.Aiming at the design requirements of clinical seed implantation surgery,narrow operating space and body lithotomy position, the configuration of ultrasonic imaging navigation of prostate seed implantation robot was analyzed.Taking material, the system energy consumption and operability, the sequential quadratic programming algorithm is used to optimize the positioning mechanism length. Considering the radioactive seed cause the radiation to the surgical environment, the needle strength and stiffness influence on positioning accuracy,safety design and static simulation analysis about the seed implantation device are carried out. The upper and lower computer control mode is adapted to design the robot controlling system, studied the open control hardware structure, the software architecture is designed.In order to improve the positioning accuracy and motion stability of the seed implantation robot, the algorithm of the acceleration and deceleration of the robot joint and the improved closed-loop control algorithm are studied. In order to avoid avoid operation accident, reduce the surgery time and energy consumption,an implantation planning method based on safe plane operation is proposed.Based on the three steps of the safe plane operation strategy, the shortest path search using Hopfield neural network and the 6-step circular and automatic seed implantation program, a safe and reliable man-machine intelligent PC control software of prostate seed implantation robot is designed.For robotic manipulation of the seed implantation device puncture the prostate, the organization will produce displacement, deformation and needle tip deflection and other issues. The effects of puncture needle diameter, tip angle,insertion speed and depth on needle deflection are analyzed by orthogonal test.The optimal combination method is given by means of range analysis method.In order to improve the positioning accuracy of the robot to control the puncture needle, a piezoelectric vibration and rotation puncture device is designed and developed. Based on the evaluation experiment of vibration and rotation puncture,a strategy of high accuracy mixed puncture is proposed, and designed the corresponding control software about puncture strategy.For resistance force of needle intervention soft tissue, gravity torque fluctuation when the robot configuration changes and friction torque of robot gear reducer,, will affect the robot's stability and control accuracy during low speed running. Set up the robot Lagrange dynamics equation, according to gravity torque, the variable gravity torque compensation mechanism of robot and mathematical model is studied and established. Through the rational allocation of technical parameters of the spring,the variable gravity torque compensation devices of cross layout spring are designed.The effectiveness of compensation mechanism is proved by and the compensation distribution simulation and experiment.In order to realize the accurate tracking of the desired position and velocity, a sliding mode robust control method based on gravity torque and fuzzy friction torque compensation is proposed.The experimental system of prostate seed implantation robot was set up. In order to improve positioning accuracy of the robot, the robot system is calibrated.In order to verify the correctness of robot's closed-loop control and the automatic seed implantation planning algorithm, the robot back to zero position, position tracking experiment and automatic seed implantation accuracy evaluation experiment are carried out respectively. The puncture effect evaluation experiment is completed by strategy of high accuracy puncture, and the experimental results validate the effectiveness of this method.