Research And Development Of A Robot Joint Module With Variable Stiffness

In recent years,with the rapid development of robotics technology,the application of robots is no longer confined to the field of manufacturing.The motivation of human-robot integration,which aims at better interaction and cooperation with human beings,has become a hot issue.Traditional robots with high rigidity can't take emergency measures as human beings when they meet emergency situations,which is very easy to cause terrible safety accidents.Therefore,it is of great significance to develop robotic joints with good flexibility and variable stiffness as human arms.In this paper,the robot joint module of variable stiffness proposed by the research group is studied in depth,and the following aspects of work are carried out concretely.(1)The joint modules with variable stiffness proposed by robotic laboratories and research institutes in major universities all over the world are investigated,and their realization of variable stiffness and modular function are analyzed and summarized.(2)Guided by the joint module of the variable stiffness robot proposed by the research group,the relevant design indexes of the joint module are determined.Comparing with the designing schemes of existing variable stiffness joint,we can find out the reference.Preliminary confirmation of the design scheme and three-dimensional modeling and simulation analysis.The corresponding mathematical models about the design is built and studied.And then combining with simulation data,all possible defects and functional deficiencies in the first generation of solutions can be found out,proposing improvement and iterating.(3)After two iteration,the final design scheme can be decided,meanwhile,rebuilding the stiffness and mechanical model for the latest design scheme of robot joints.The mathematical model is analyzed by MATLAB with comparing the analysis results with ADAMS simulation results.Then,according to the contact force situation in the analysis,the model is imported into ANSYS to check the strength of the core components of the whole joint,and these components are optimized according to the drawn stress and strain nephogram to ensure that the joint can work normally under the expected load.(4)The dynamic and position control models of the joint are established.According tothe characteristics of the joint with manual adjusting variable stiffness,the dynamic model of SEA(series elastic actuator)can be used for reference,and the dynamic and position control models of the joint are built in Simulink to analyze its characteristics,respectively.According to the final design scheme,a joint prototype is built.The experimental data are collected and the error sources between the prototype and the theoretical model are analyzed.The results show that the proposed joint has variable stiffness function,but the load capacity of variable stiffness module should be verified more,the stability and reliability of this joint need to be optimized and improved.