Design And Analysis Of Wearable Human Lower Limb Rehabilitation Mechanism

In this paper,a wearable lower limb rehabilitation mechanism based on parallel structure is designed for patients with hemiplegia grade 4-5.The structure design,kinematics,trajectory planning and dynamics of the mechanism are analyzed.Specific research is as follows:Firstly,the composition and motion characteristics of human lower extremity joints are briefly analyzed based on the theory of rehabilitation medicine and ergonomics.Human lower limb rehabilitation institutions mainly focus on the rehabilitation raining of lower limb joints,mainly hip,knee and ankle joints.On the premise of satisfying the structural parameters and motion characteristics of human lower limbs,the size and form of the rehabilitation mechanism of human lower limbs are determined to ensure that the designed mechanism is equal to the degree of freedom of human activities,and then the designed model is established by using Solidworks software.Secondly,according to the designed mechanism,the kinematics model is established and the kinematics analysis is carried out.It mainly includes:calculating the degree of freedom of the mechanism;establishing the forward and backward position model of the mechanism by using the vector closed-loop method;using the software of MATLAB to simulate the kinematics of the established mathematical model;inporting the model established in Solidworks into Adams software to obtain the kinematics simulation of the model,and verifying the correctness and model of kinematics analysis by comparing the kinematics curves of the two models.Feasibility of preliminary design of the type.Then,the virtual protot)ype model of the designed mechanism is built in Adams.The trajectory planning is carried out by S-type,T-type and modified T-type driving modes respectively.The optimal traj ectory planning mode is selected according to the trajectory of the moving platform,and the motion curves of each joint are obtained.Then the sample points are selected and the trajectories described in Atlab and Adams are compared.The rationality and applicability of the designed mechanism are illustrated by comparing the motion angle of the moving platform with that of the hemiplegic patients.Finally,the dynamics of the designed mechanism is analyzed.For 3-UPU hip rehabilitation mechanism,the dynamic model based on virtual work principle is used to analyze,and for 2-UPS/RRR ankle rehabilitation mechanism,the dynamic model based on Newton-Euler method is used to analyze.The inverse dynamic model of the mechanism is established and the numerical simulation is carried out by the software of Matlab.Then the correctness of the mathematical model is verified by simulation with Adams software.The dynamic analysis of the ankle rehabilitation mechanism under the optimal trajectory planning mode shows that the designed mechanism can meet the rehabilitation needs in theory.