Thestudy Of The Simulation Of Lower Limb Activity In The Elderlybased On MATLAB

Due to the decline of the elderly’s physical function is very serious, the 70 years old’s physical function is only half of the 30 years old’s, the elderly’s sports problem is particularly prominent.By researchers’ study of human movement,we found that the most activities in the life require the participation of the leg, so the study of the lower limb activity of elderly is a very meaningful topic.The motion parameters of the lower limbs are obtained by the acceleration sensors placed on the thigh, the flexible sensors placed on the knee and the pressure sensors placed under the feet.the acceleration sensors and flexible sensors can measure the movement angles of the hip joint and knee joint, so that we can get the elderly’s motion parameters like angles, angular velocity and angular acceleration; The pressure sensor can measure the forces of the feet.According to the characteristic of the elderly’s activities and the human body structure we can build the mathematical modeling of the lower extremities.Through the comparison of common modeling methods and the requirements of this project, the Lagrange method was chosen to build the dynamic model of the lower extremity. And use the software of SimMechanics to build the simulation modeling of elderly lower extremity.Due to the mass of the human foot is far less than the quality of other members, so neglected ankle rotation during modeling, we set up a 2 rigid body model for the unilateral lower limb.Due to the traditional human gait cycle is divided into support and swing phase, we need to consider the interaction between foot and ground in support phase, and we don’t need to consider the interaction between foot and ground in swing phase, so the simulation model is established for support and swing phase respectively.We should input the motion parametersinto the SimMechanics,and thesoftware will output the joint torque. Then we compare thejoint torque which output by software with the joint torque which is calculated by mathematical model, they are roughly matched, so we validate therationality of the simulation model.Then we use the regression analysis method to model the elderly’s joint torque and time, and infer the expression of the joint torque and time.Software simulation model and mathematical model of the joint torque and time is good to provide the experimental data for the research of elderly’s lower limb activities.