Design And Experiment Of Surgical Robot System For Rectal Cancer

Colorectal cancer is a malignant tumor of the digestive tract.Among the malignant tumors in the world,the incidence of it ranks third and the mortality rate of colorectal cancer ranks second.Previously,the main treatment for colorectal cancer was natural orifice specimen extraction surgery(NOSES),similar to Natural Orifice Transluminal Endoscopic Surgery(NOTES).The method of this surgery is to drag the lesion out through the natural cavity,mainly for the treatment of rectal cancer.This surgical method currently mainly uses hand-held minimally invasive instruments for surgery,which is difficult to learn,has a small working space and may leave scars on the patient’s body surface,affecting the appearance.At present,Surgical robots appeared and have been rapidly developed.They have solved the difficulties faced by traditional NOTES instruments and make it possible for NOTES to popularize.Therefore,the development of NOTES surgical robots for colorectal cancer which is easy to learn and has large working space has become an inevitable trend.Aiming at the natural orifice transluminal endoscopic surgery of the rectum,facing the key problems in rectal cancer surgery,this paper proposes a new design method of NOTES surgical robot for rectal cancer.The specific research results are as follows:According to the physiological parameters of the rectum and the needs of rectal cancer surgery,the design requirements of the robot are proposed.According to the design requirements,it is determined that the slave manipulator needs to include an instrument arm,two nested tool arms and a feed module,with a total of 13 degrees of freedom.The instrument arm has a diameter of 20 mm and it adopts a configuration method of active and passive combined and has two deflection degrees of freedom.The tool arm has a diameter of 7mm,uses a "one" drive layout,adopts a configuration method of active and passive combined and has five degrees of freedom(one feed,two deflection,one for rotation and one for instrument opening and closing).The tool arm carries different instrument and reaches the lesion location through the tool channel on the instrument arm,forming an operation triangle,and performing the operation.After completing the design of the slave manipulator,design and manufacture the master manipulator for supplementary use with the slave manipulator.Analyze the layout of the degrees of freedom of the tool arm and the physiological parameters of the human body,combined with the ergonomic design method,developed a masterslave isomorphic,five-degree-of-freedom master manipulator with serial structure and force feedback,and performed passive and active gravity balance.After completing the master-slave manipulator design,use the D-H method to analyze its kinematics to verify that its motion space meets the design requirements and determine the mapping ratio by the size of the motion space of each corresponding joint of the tool arm and the master manipulator.Based on the research results above,experiments were carried out on the static and dynamic performance of the slave manipulator and the control accuracy of the master manipulator.After completing the separate functional experiments,the master and slave manipulator was integrated,and the simulated rectal polyp resection experiment was carried out to comprehensively evaluate the performance of the system to verify its feasibility.