不同坡度与负重步行的下肢关节负荷仿真研究

Loads on joints of lower extremities when walking along different slopes or under different weights

目的仿真分析不同坡度与负重步行的下肢关节负荷,为下肢助力装置设计及损伤防护提供理论依据。方法基于人体肌骨模型构建不同地面坡度和负重条件下的步态仿真模型,通过设定步态控制算法、目标函数,采用协方差矩阵自适应进化策略(CMA-ES)得出步态模拟结果并分析下肢关节负荷。结果平地行走的下肢关节运动学与动力学数据仿真结果与试验数据误差在2 s以内;仿真结果表明上坡时几乎所有关节负荷增加,下坡时膝关节伸展力矩增加;步行中主要是髋、踝关节做正功且随上坡坡度增加而增加,下坡坡度增加而减小,负功无明显变化;膝关节负功大于踝、髋关节,且在下坡时随坡度增加而增加;当负重达20%体重时关节负荷有明显变化。结论该仿真模型为不同坡度和负重步态的下肢运动学与动力学分析提供了非试验方法,对下肢损伤防护及助力装置设计具有一定参考价值。

Objective To simulate the loads on lower extremity joints when one walks along slopes of different angles or under different weights in order to provide data for the design of extremity-assisting devices and for protection against injuries.Methods Gait simulation models of walking along slopes of different angles and under varied weights were established based on human muscle and bone models.The gait control algorithm and objective functions were set by software SCONE while the results of gait simulation were obtained via the covariance matrix adaptive evolution strategy(CMA-ES).Results The error between the data on kinematics&dynamics of lower extremity joints and findings of experiments when one walked on the flat ground was less than 2 s.The results of simulation suggested that the loads on the joints were increased when one walked up the slope,and that the extension torque of knee joints increased when one walked down the slope.The positive work of hips and ankles increased with the angle when one walked up the slope,but decreased with the angle when one walked down,and negative work hardly changed.The negative work of knee joints exceeded that of ankles and hips,and increased with the increasing angle of the slope when one walked down.When the load reached 20%of the body weight,the load on joints changed significantly.Conclusion This simulation model is expected to provide a nonexperimental method for analysis of the kinematics and dynamics of lower extremities along slopes of different angles and under different weights.This model is of some referential value for the protection against lower limb injuries and for the design of walking-assisting devices.