无动力下肢负重外骨骼人机动力学及其储能元件刚度优化EI北大核心CSCD

为提高人体搬运效率,降低人体关节损害,提高外骨骼能量利用效率,基于人机动力学对一种无动力辅助负重下肢外骨骼的储能元件刚度进行优化。应用牛顿-欧拉动力学方程建立人机耦合动力学模型,得到各关节力矩与大小腿长度和质量、关节转角及弹簧刚度关系的数学模型。将三维动作捕捉系统采集的角度数据代入动力学方程中,通过MATLAB进行计算得到关节力矩动态变化规律。建立人机系统各部分的能量流动模型,并进行步态周期内的能量流动分析,以储能元件刚度为参数,储能元件的能量流动为约束条件,各关节平均力矩最小为目标建立优化模型,通过与AnyBody人体仿真软件获得的人体模型作对比验证优化结果的正确性。结果表明,穿戴优化后外骨骼减轻了下肢着地时对人体的冲击,有效降低了人体能耗和下肢关节转矩。

Human-machine dynamics and stiffness optimization of energy storage elements for unpowered lower limb loadbearing exoskeleton

In order to improve the efficiency of human transport,reduce the joint damage and improve the energy utilization efficiency of the exoskeleton,the stiffness of an energy storage element of the lower extremity exoskeletons was optimized based on manmachine dynamics.The Newton-Euler dynamics equation was used to establish a man-machine coupling dynamics model.The mathematical models of the relationship between the joint torque and the length,mass,joint angle and spring stiffness were obtained.The Angle data collected by the 3D motion capture system was substituted into the dynamic equation,and the dynamic variation rule of joint torque was calculated by MATLAB.The energy flow model of each part of the man-machine system was established,and the energy flow analysis in the gait cycle was carried out.The stiffness of the energy storage element was taken as the parameter,the energy flow of the energy storage element was taken as the constraint condition,and the minimum torque of each joint was taken as the goal to establish the optimization model.By comparing with the human model obtained by AnyBody human simulation software,the correctness of the optimization results was verified.The results showed that the wearable exoskeleton can reduce the impact of lower limb landing on human body,effectively reduce the energy consumption and the lower limb joint torque.