| Robot-assisted minimally invasive vascular interventional surgery can well overcomeshortcomings of traditional minimally invasive intravascular interventional surgery, whichcan free doctors from surgery scene, and avoid ray radiation hurt body of doctors. In thewhole process of surgery, with the help of three-dimensional medical image, doctors controlthe catheter robot that manipulates catheter outside operating room, and they can be morecomfortable to do surgery. The existing researches on catheter robot system focus onconstruction of the system and development of related key technologies, and researches onsystem control are few, open loop or simple proportional integral differential (PID) controlschemes are applied to catheter robot system. However, movement of catheter in bloodvessels is interfered by some uncertain disturbance factors during slave side conveys catheter,control performance of system and transmission precision of catheter and security of surgeryand so on are worse when system adopts these control schemes. In this paper, the controlproblems of master-slave catheter robot system are studied, and intelligent control methodsare applied to the system, to improve control performance of system, and also to improveconveying precision of catheter and security of surgery.Firstly, the overall structure of minimally invasive vascular interventional surgerymaster-slave catheter robot system and the function of some main parts such as master, hostcomputers control system, slave side control card, catheter robot and catheter are introduced.Meanwhile, kinematic model of catheter distal bending section is established, to getmovement transitive relation from proximal to end of catheter, and inverse Jacobian matrixis obtained by analysis and calculation, which will be applied to position control of catheter.Then, to solve existing problems of PID control scheme which is universally applied tocurrent system, master-slave catheter robot system based on adaptive fuzzy PID control isdesigned, to improve control performance of catheter robot system. The simulation resultsshow that adaptive fuzzy PID control scheme can both reduce system shoot and quickenresponse of system, and enhance ability of resist disturbance, improving the controlperformance of catheter robot system.Finally, on the basis of catheter robot system adaptive fuzzy PID control, catheter robotsystem based on three-dimensional fuzzy control is also designed. The three-dimensional fuzzy controller is an adaptive PID controller with variable structure, which has excellentcontrol performance. The contrast analysis of simulation results show that the system hassmall shoot and fast response speed and strong robustness, making it perfectly trackingcontrol command, when three-dimensional fuzzy control scheme is applied to catheter robotsystem. The control scheme improves control performance of system significantly, andensures safety of surgery. |
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