The Research On Vibration Characteristics Of Medical Flexible Manipulators

The medical flexible manipulators have extremely high r equirements on the positioning accuracy and movement stability of their ends during the process of patients receiving radiotherapy.However,due to the flexibility of the rod and the joints,it is difficult to accurately control the position and speed of t he medical robot arms.And it is extremely easy to generate vibration,which is very unfavorable for the purpose of radiotherapy positioning accurately and speeding up.However,it is almost impossible to completely eliminate the impact of the flexibility of the medical flexible manipulators on the terminal vibration.This subject takes the medical flexible manipulator as the research object,after fully understanding its structural characteristics,comparing various related dynamic modeling methods and weighing their pros and cons,we find the modeling method suitable for the research object of this subject,then we establish the model,conduct theoretical analysis and software simulation on the purpose of studying the factors that may affect the vibration of the terminal,getting the relevant laws of the terminal vibration,the main works of this article are listed as follows:(1)Discuss the research background and significance of this subject,elaborate the application status of medical flexible manipulators at home and abroad,and introduce the structural characteristics of the six-degree-of-freedom medical flexible manipulator independently developed by the research group and simplify it without affecting the target result,consider four dynamic boundary conditions and calculate the natural mode and main mode function under different conditions,select the appropriate discretization method and dynamic modeling method,use the first six orders of natural vibration mode as an example of the cantilever beam,analyze and select the first two order modal coordinates that meet the accuracy requirements of the subject.(2)Considering the two aspects of joint flexibility and rod flexibility,the simplified physical models of flexible joints and flexible rods are established by the Lagrange equation and the assumed modal method,,The dynamic models of f lexible joint-rigid rod、 rigid joint-flexible rod、flexible joint-flexible rod are established respectively,and then their respective vibration equations are derived.(3)Through the control variable method,a series of parameters are modified,and the single rod and double rod flexible manipulators are taken as examples to discuss the influencing factors of the vibration displacement of the end of the medical flexible manipulator by using MATLAB simulation.Establish a correlation model of the influence of various factors on the vibration displacement of the end of the medical flexible manipulator,and analyze the influenc e weight.(4)Combined with 3D modeling software named Solidworks and simulation software named ANSYS,the modal vibration mode of the double-rod medical manipulator related to the arm configuration and end load heavy were analyzed for the influence on the the mode shape of the arm.By the research of this article,we can seek advantages and avoid disadvantages at the beginning of the structural design,or we can design the controller in the later stage to eliminate the influence of main factors.It is als o an effective way for medical flexible manipulators to achieve the target of high precision and fast control.