Modeling And Optimization Of Rigid-Flexible Coupling Humanoid ARM

With the rapid development of robotic technology,the humanoid arm with high flexibility has been widely used in the fields of medical treatment and services,because of its advantages of low mass,high power density,and perfect human-robot interaction.However,the new flexible actuator is different from the traditional actuator,such as engine.The coupling of flexible actuator and rigid structure is the current research emphasis.Establishing an accurate and feasible model is of great significance for the research of rigid-flexible coupling humanoid arm.Based on these reasons,this thesis employs the optimization technology to improve the performance of the humanoid arm,especially its power density.Therefore,this thesis concentrates on the research of flexible-rigid coupling arm.The main research works are as follows:Firstly,the mathematical models of flexible actuators are established,including:(a)The complete statics model of the Pneumatic Muscle(PM)was established considering elasticity of the rubber tube and the friction between the rubber tube and the fiber textile;Comparison between the established model and the ideal mathematic PM model was conducted,which confirms the feasibility of the proposed statics model;(b)The constitutive model of the Shape Memory Alloy(SMA)actuator was derived based on the analysis and combination of the SMA thermal model,phase transmission model,and the stress-strain model.Secondly,based on the mathematical models of flexible actuators above and structure of the home-made coupled humanoid artificial arm,the dynamics models of the elbow joint and wrist joint of the robotic arm were established,respectively,based on the structure of the joints and their associated actuator models.Thirdly,according to the dynamics models above,the constraints,the variables,and the fitness function has been established.The optimization is realized by using the Matlab/genetic algorithm toolbox,performance comparison between the models before and after optimization was also carried out.Fourth,a smart SMA based PMA actuator has been designed,for the purpose of improving the performance of the flexible actuator.Through simulation with Matlab/Simulink,the results show the performance of smart pneumatic muscle has been highly improved,compared with the traditional pneumatic muscle.