Design And Research On The Rotating Joint Of Flexible Cable Drive With Large Reduction Ratio And High Rigidity

With the development of human-robot collaborative robot technology,the flexible cable transmission manipulator is characterized by its flexibility and zero backlash,low friction and low inertia of the transmission system,so that it has a good performance in vibration absorption,impact mitigation and other aspects.At the same time,it also has good positioning accuracy and fast drive response capabilities,thus becoming a research hotspot in the field of human-robot collaborative robots.As a key component of the robotic arm,the performance of the joint determines the range of motion,accuracy,carrying capacity,and dynamic performance of the robotic arm.In this paper,the flexible cable transmission rotating joint is taken as the research object,and the topological structure design,kinematic modeling,transmission performance and simulation analysis are mainly studied.The design method of the flexible cable transmission rotating joint is preliminarily formed,which provide technical support for its application in flexible cable transmission mechanical arm.The main content of the paper includes the following aspects:First,based on the characteristics of differential gear train transmission,on the premise of the analog analysis of flexible cable transmission and gear transmission,the motion separation method is used to systematically study the configuration design of the rotating joint of single-degree-of-freedom flexible cable transmission,and a differential principle is proposed.A method for topological design of revolute joints of one degree of freedom based on differential principle is presented.Secondly,the kinematics analysis is performed on a selected type of flexible cable rotation joint,and the analogue method of the flexible cable transmission system is equivalent.The matrix method,which is suitable for kinematics modeling of gear train,is applied to the flexible transmission revolute joint.And the directed graph method was used to verify the kinematics analysis results to prove the feasibility and correctness of the mating method applied to the kinematics modeling of the flexible cable transmission system.The two modeling methods were compared and analyzed.Thirdly,the classical creep theory,Euler formula,etc.are used to analyze the mechanical characteristics of the flexible cable transmission system,and the analytical expressions of the flexible cable transmission rotation joint transmission backlash and transmission stiffness are derived.Based on Matlab,the influence of main design parameters such as preload,friction coefficient,elastic modulus and external torque on the transmission stiffness and the transmission return is analyzed.Finally,the simplified transmission method and the discrete method are used to model and simulate the basic transmission unit respectively.The characteristics of the two methods are compared to determine the modeling scheme of the rotating joint.The modeling analysis of the rotating joint of the flexible cable transmission is completed in the ADAMS virtual environment,which prove the correctness of the kinematics equation.