System Design And Motion Control Of Continuous Concentric Tube Robot

With the rapid development of medical technology,surgical minimalization has become an important stage in surgical operation.The purpose of minimally invasive surgery is not only to minimize the wound but also achieve the level of traditional surgery and quality,it is expected to reduce the size of the wound,release the patient's pain,and accelerate the recovery after surgery.Meterialogy,sensors,computer technology robotic control theory and other emerging intustries are booming,high security,more stable,accurate and operable medical robots have been the tendency in minimally invasive surgery.This paper proposed a continuous concentric-tube robot(CTR)which is slim and bending flexibly,applied in minimally invasive surgery.Compared to tranditional surgical robots,CTR is surperior in small size,flexible bending so it can work in tiny space and adapt well to non-structural environment with lots of obstacles.Composed of multi-section precurved tubes which are made by super-elastic nikel-titanium alloy,they can present different shapes when they extend and rotate with respect to each other.The semi-rigid structure of the concentric tube guarantees enough flexiblilty and ensures that the movement of the concentric tubes in the organ tissue is adequately resisted by external forces.The research on continuous concentric tube robot using new material can play an important role in the development of related robot technology and minimally invasive surgery.In this paper,the structure design of four Do Fs concentric-tube robot and the parameter optimization and system design of robot are put forward.We proposed a CTR with 38 cm in length and 1.85 kg in weight which is assembled on a five-Do F robotic arm to enable surgeons to perform various surgeries.Thus,the robotic platform is contructed.Secondly,based on Lie group theory,the kinematics model of the robot is established,and the path planning simulation of the robot in the restricted space is realized by using the RRT-Shape algorithm.In addition,this paper proposes a method to estimate the image Jacobian matrix based on Kalman filter to realize the visual servo ing research on concentric-tube robot.Finally,to estimate the shape of tubes in real time for safety,the multi-target magnetic localization algorithm is used to reconstruct the shapes of concentric tubes,and the reconstruction accuracy is about 1.5mm.In the skull model,the experiment proves the effectiveness and reliability of the continuous concentric tube robot,and a variety of sensors effectively improve the control precision,which will play a positive role in the progress of minimally invasive surgery.