Design And Control Of Virtual Feedback Force Device For Needle Insertion Of Surgical Robot

Needle insertion is used widely in many medical diagnosis and treatments.Traditionally,needles are manually inserted into the body under image-guidance.This will cause repeated exposure in X-rays for surgeons.Teleoperated needle insertion system is an effective way to protect the physician.The process of needle tip position is under continuous control of the physician while the patient is kept in remote scanner.Studies have shown that real-time haptic feedback can make the operation process more safe and efficient and improve the operation accuracy.During the needle insertion process,haptic device gives real-time feedback force to operator.In this paper,a 2 degrees of freedom(DOF)haptic device is designed for needle insertion surgery,which mainly includes the following tasks:Firstly,combining characteristics of needle insertion force and criteria of haptic interaction,we carried out mechanical design for 2-DOF feedback device and modeled electromechanical driving system.Secondly,insertion forces of tissues of chicken and pork are modeled and analyzed,it helps analyze the entire process of needle insertion more clearly.Experiments are conducted to analyze the effect of needle diameter and velocity for insertion force.Then,a novel force control framework is proposed,which includes two control loops to match the force signals from slave robot to feedback force precisely.The inner loop is a current controller,the outer loop is a force-tracking PID controller.Finally,the effectiveness of the proposed method is verified by experimental results.