Modeling And Co-simulation Of Lower Limb Rehabilitation Robot System

In recent years,with the rise of rehabilitation industry,the theoretical research of rehabilitation robot as the foundation of future robot development has been paid more and more attention by researchers.In this paper,a lower limb rehabilitation robot for swing phase gait training of early stroke and lower limb hemiplegia was developed based on ergonomics.Taking the mechanical system as the research object,the statics,kinematics and dynamics were analyzed.The research contents are as follows :Combined with the structural characteristics of human lower limb muscles and bones,the principle of gait occurrence,the mechanism of gait training and the evaluation criteria were expounded from the perspective of human anatomy.The three-dimensional structure of lower limb rehabilitation robot was analyzed,including transmission system design,joint limit and telescopic mechanism.In order to study whether the stiffness of the mechanical structure of the lower limb rehabilitation robot under external excitation met the design requirements,the strength analysis of the structure of the lower limb rehabilitation robot under static load was carried out.Then the natural frequency and vibration mode of the whole structure were analyzed by modal analysis.Focusing on the problem of configuration coupling,a geometric decoupling method based on independent joint kinematics theory is proposed.The forward and inverse mapping equations of the drive motor and the joint are derived,and the inverse kinematics model of the joint connecting rod is further derived combined with the configuration characteristics.Combined with the configuration characteristics,the inverse kinematics model of the joint connecting rod was further deduced.Based on the law of conservation of momentum,the dynamic equation of simplified joint connecting rod of lower limb rehabilitation robot was derived by Newton Euler method,and the application limitations of the equation were analyzed.The kinematic virtual prototype model of the lower limb rehabilitation robot was established,and the mapping relationship between the joint and the motor of the kinematic model and the analytical model of the virtual prototype was verified by data exchange with MATLAB.Aiming at the uncertainty of the dynamic equation parameters and the model compensation problem of the simplified joint connecting rod,the dynamic virtual prototype model of the whole machine was established.Through the experimental comparison of PD control and PD-RBF neural network dynamic control,the compensation torque of the model was obtained,and the effectiveness of the virtual prototype dynamic model was further verified.Compared with the traditional kinematics and dynamics system modeling,this paper proposed a virtual prototype co-simulation modeling method,which could truly reflect the motion characteristics of the lower limb rehabilitation robot mechanical system and effectively reduced the experimental cost.