Dynamics Modeling And Control Strategy Of Lower Limb Exoskeleton Robot

Nowadays,the aging of the society is increasing.The number of patients with lower limb disabilities such as stroke and spinal cord injury has increased.People’s acceptance of rehabilitation training equipment has increased.People’s demand for intelligent rehabilitation equipment becomes larger.In this paper,we propose to design a rehabilitation robot with DC servo motor exoskeleton.The structure is designed according to the application scenarios and training needs of rehabilitation patients,and the kinematics and dynamics analysis of the movable mechanism is modeled to improve the system control accuracy.The trajectory tracking control of the lower limb rehabilitation exoskeleton and the speed synchronization control of the mobile platform are investigated to meet the diversified rehabilitation training needs of users.The research content of this paper is as follows.(1)For the analysis of the physiological structure of human lower limbs and the walking posture of healthy people during walking.The design requirements of the rehabilitation robot are obtained.According to the body differences of different users,a variety of adjustment mechanisms are designed to meet the training needs of users with different height and weight.The mobile platform with active movement function is designed to meet the walking needs of users during rehabilitation training.(2)Through the motion analysis of the mobile platform of the robot,the motion relationship between the universal wheel and each driving wheel is established.The dynamic model of mobile platform is established by D ’Alembert principle.(3)The Minisun IDEEA3 device is used to collect the Angle change curve of human walking joints,which is used as the ideal trajectory of joint motion.In the process of exoskeleton dynamics modeling,the unknown friction is compensated through fuzzy control and radial basis neural network.The control system was built in MATLAB/Simulink,and the dynamics model of the lower extremity exoskeleton was simulated and analyzed respectively.Good trajectory tracking results were obtained,tracking error less than 4°.In order to protect the safety of users in the process of rehabilitation training,a joint simulation system of MATLAB/Simulink and MSC.ADAMS was built,and the speed synchronization simulation was realized through PID control.(4)The experimental prototype of rehabilitation robot has been built.Through the functional test,it is proved that the rehabilitation robot achieves the design goal.The feasibility of the exoskeleton trajectory tracking control and speed matching control strategy is verified through the physical prototype experiment.