Research On Lightweight Design Method Of The Robotic Arms Based On The Torque-density Curve

With the development of science and technology and robot technology,robotic arms have been widely used in industrial,agricultural,national defense,major scientific research,medical,educational,entertainment and family services,which are gradually changing people's production and life style.From the relevant development plans of the country point of view,the light,safe,efficient and energy-saving problem is always the current research hotspot of the robotic arms.In the traditional design process,in order to ensure the strength and stiffness requirements,the simplified computing or system module integration design method was applied so that the problems of the excessive use of materials,high energy consumption,low load/weight ratio become more obvious,which don't meet the light,safe,energy efficient design concept.Therefore,the study of lightweight design method of robotic arms has potential engineering application value.In this paper,based on the comprehensive analysis of the lightweight research of robotic arms at home and abroad,in order to solve the unified design problems of structure and drive trains,the lightweight design method based on the torque-density curve was proposed.Then,through the combination of theoretical modeling,simulation and experimental verification the lightweight design of the specific implementation and validation were completed.The specific research contents are as follows:(1)The mathematical models of robotic arms under the certain working conditions were established.In this paper,the lightweight design problem of robotic arm were completed under the certain constraints.In order to describe the design of the robotic arms,it is necessary to establish the relevant mathematical models,including kinematics model,finite element analysis model and dynamic model.The analysis of manipulator workspace and motion characteristics was implemented based on the kinematics model.To evaluate the structural stiffness and strength constraints the finite element model was built.The dynamic model was established based on the principle of using mechanical manipulator and calculated the driving torque of each joint in the process of motion to provide a theoretical basis for the drive trains design.(2)A lightweight design method based on the driving torque-density curve was proposed.For the the same topology drive trains,in this paper a quantitative expression on the torque and mass was presented,which is named "driving torque-density curve".By aiming at the design characteristics of the structure and drive trains,a unified design method of the structure and drive trains was proposed by selecting the appropriate design variables,constraints and lightweight design function.Based on the given design data,the reference design method and the design method of this paper were implemented to design the robotic arm,respectively.By the comparisons and analysis of the optimization results,the feasibility and effectiveness of the proposed design method in this paper were verified.(3)The robotic arm prototype and experimental verification were completed.First,a robotic arm prototype was completed based on the parameters of the structure and drive trains of the lightweight design.Then,the simulation and experimental modal analysis on the robotic arm were implemented to verify the correctness of the simulation model.Finally,the reliability of the presented lightweight design method was verified by the measurement and analysis of the vibration amplitude and the joint torque.