Study Of Ultrasound-guided Robot For Percutaneous Microwave Ablation Of Liver Cancer

The surgery of ultrasound-guided percutaneous ablation of liver cancer is a minimally invasive technique to treat liver cancer, which is conducted by the ultrasound guidance, taking advantage of the microwave thermal ablation effect to kill the liver cancer. This paper has designed the ultrasound-guided percutaneous ablation robot to automatically adjust the needle position and orientation. With the medical robot’s help, the labor intensity of the doctor can be greatly reduced, and the surgical precision would be maximize improved as well, so did the success rate.This paper designed a mechanical structure of ultrasound-guided percutaneous ablation robot and established a kinematic model and an error model for the accuracy of the experiments. The main contents include:(1) The front-end RCM needle mechanism, passive arm structure with self-locking function, back-end three-dimensional translational platform. The structure of passive arm can be a implementation of coarse positioning function. The back-end three-dimensional translational could be a helper of the passive part precisely positioning. The remote center of motion (RCM), could help the needle on the position adjusting. The RCM and the three-dimensional translational platform was designed to achieve rapidly decoupling of the needle position and posture.(2) For the comparative traditional D-H kinematic modeling, Lie algebra was used to analyze the forward kinematics, a comparative study of the two methods on computation and storage requirement was worked out. Matlab was used to simulate kinematics model, the mechanism motion model of RCM was also established and analyzed by the Adams software, the results had proved that the RCM structure was conductive to the inverse kinematics decoupling.(3) Based on the kinematic model, the method of Monte Carlo used to analyze the robot’s workspace, the results had verified that the robot had sufficient scope and flexibility to meet the requirements of clinical surgery.(4) The differential transform method was presented to obtain the relationship between the end-reference point of robot and its geometry parameter error. The relational expression of the two had been calculated, it was a matrix model. The positioning accuracy experiments of the puncture robot was also conductedExperimental results show that:relative accuracy of the puncture robot meets the surgical precision well, the error sources and reasons for puncture robot had been given, the results could be good suggestions for the robot design,manufacture and assembly.