基于重力势能转化的下肢外骨骼设计与动力学研究

Design and dynamics research of lower extremity exoskeleton based on gravitational potential energy transformation

基于人体重力势能转化的弹性助力原理,设计了一款下肢外骨骼,其类型为被动式,可为髋关节提供助力。依据拉格朗日方程建立了下肢外骨骼数学模型,研究了该模型在释能阶段的髋关节转矩。利用Adams软件建立了下肢外骨骼动力学仿真模型,通过数理统计的方法对比了数学模型和动力学仿真模型髋关节转矩的计算结果,得出两者高度相关。利用Adams软件仿真分别得出了人体在穿戴下肢外骨骼和不穿戴下肢外骨骼情况下释能阶段的髋关节转矩曲线,以髋关节做功值为依据对两组髋关节转矩曲线做了对比分析。结果表明,穿戴下肢外骨骼时,释能阶段髋关节做功值减少了19.29%。最后,以储能弹簧刚度与预拉力为设计变量对下肢外骨骼髋关节转矩进行优化,得出最适储能弹簧刚度下穿戴下肢外骨骼时髋关节做功值比不穿戴下肢外骨骼时减少了26.00%。

Based on the principle of elastic power conversion of human body s gravitational potential energy,a lower extremity exoskeleton of passive type was designed to provide power for hip joint.A mathematical model of lower extremity exoskeleton was established according to Lagrange s equation,and the hip joint torque of the model at the energy release stage was studied.The Adams software was used to establish a lower extremity exoskeleton dynamics simulation model.The mathematical and statistical methods were used to compare the calculated results of the hip joint torque of the mathematical model and the dynamics simulation model.It was concluded that the two were highly correlated.The Adams software was used to simulate the torque curve of the hip joint in the energy release stage with and without the exoskeleton of the human body.Based on the work value of the hip joint,the torque curves of the two groups were compared and analyzed.The results showed that when exoskeleton was worn,the hip joint work value during the energy release stage was reduced by 19.29%.Finally,using the stiffness and pretension of energy storage spring as design variable to optimize the torque of the exoskeleton hip joint.It was concluded that the work value of the hip joint under the optimal stiffness could be reduced by 26.00%compared with that without the lower extremity exoskeleton.