Catheter Inserting Robot Control Research Based On Minimally Invasive Vascular Surgery

In recent years, the number of cardiovascular disease patients and the incidence rises gradually, the demand for cardiovascular surgery is increasing. The typically minimal invasive surgery for cardiovascular disease is cardiovascular intervention. In the whole process of a traditional cardiovascular intervention surgery, doctors have to insert the catheter and diagnose on the spot, so they are inevitably exposed to harmful radiation, which harms them a lot if they operate chronically. In addition, a series of the operations during the catheter insertion is extremely fine, which makes high demands of the doctor’s operative skills and experiences. Especially, the doctor cannot receive the force between catheter and cardiovascular correctly, which lead to perforation and other surgical complications.Centering on the catheter inserting assistance robot used in cardiovascular intervention surgery, this article focus on the control of this robot system aiming at solving the problems existing in the traditional catheter intervention surgery mentioned above. The system has master-slave structure, the master side contains the control handle and human-computer interface, the slave side is the servo system based on the PMAC control. Catheter insertion is sending force/position commands by the handle or PC to control the slave machine send catheter into cardiovascular. This article focuses on the security and precision of this catheter insertion system.Do the research on the security of the catheter insertion, and receive the force feedback function and force control function of the manipulation system. The operator is provided with more vivid tactile information by the integration of micro force sensors at the end of the catheter and the mapping of force information captured into the operation handle at the main side. Force control is researched based on the relationship between the force and position of the catheter, which is summarized by the experiences of manual delivery of the catheter. The force control at the end of catheter is realized based on the method of the impedance adjustment and fuzzy control algorithm. At last, the force control algorithm is simulated and analyzed. The result shows that this algorithm can guarantee that the force at the catheter tip is restricted into the expected range.Considering the operation accuracy of the system, the widely used catheter inserting half-closed loop control algorithm based on PMAC is first adopted. On this basis, the full-closed loop control algorithm base on the position at the end of catheter is proposed. Besides, the improved PID algorithm and intelligent PID algorithm is utilized to implement the fast, steady and precise tracking of the expected position. At last, the position control algorithm is simulated and verified. The result shows that the proposed full-closed loop control algorithm have greater accuracy and stability than the half-closed loop control algorithm.The force feedback technology and force control strategy proposed in this paper can guarantee the security during surgery. and the full closed loop position control strategy improves the accuracy and stability of the catheter inserting process. The development and improvement of these functions is necessary to improve the security and accuracy of surgery.