Integrated Design And Optimization Of Modular Joint For Lightweight Arm

Lightweight manipulator whose core is modular joint has the advantages of high torque-to-weight ratio,flexible operation,energy saving and safety,which is favored by many fields of industry.With the upgrading of social industry of China,more and more groups develop modular joint to meet the need of market.The lightweight manipulator is limited on some fields where high servo performance is required,and the reason is that structure of modular joint limits the improvement of servo performance.To solving the problem,an integrated design method for improving the lightweight manipulator servo performance is employed in this thesis.In order to enhance the servo performance by improving system,this thesis has done the following work:First of all,the process of designing modular joints by traditional method has been discussed.In order to study the parameters that affect the servo performance of the joint,a mathematical model of power train has been modeled and analyzed,as well as the open-loop transfer function of the joint has been used for analyzing the coupling of the motor and the transmission system.Secondly,the parameters that affect joint servo performance have been analyzed,which include stiffness of drive train,gear ratio of harmonic drive,the inertia of the output and motor shaft,the natural frequency of the transmission chain,the natural frequency of the motor electromechanical characteristics and the weight of the joint.Following the orientation of improving joint performance,a development of the joint overall layout has been done.Based on the analysis,the optimal objection function and constraints have been determined.The continuous variables have been discrete and optimal result has been searched by the exhaustive method with MATLAB software.The comparison has been done with the first generation and the reasons for improving servo performance has been analyzed.A joint specific brake has been designed and the reliability of it has been check by the method finite element analysis(FEA).The reliability of the joint motor has been analyzed by the method of FEA of the motor magnetic field.The strength and the deformation have been analyzed by the method of FEA and the effect of deformation of joint parts to joint stiffness has been estimated.After comparing the results with the first generation,a conclusion has been drew that the performance-oriented design method which join the motor and drive train together can improve the joint servo performance effectively.