无动力储能式截瘫助行外骨骼弹簧刚度优化
Optimization of an unpowered energy-stored exoskeleton spring stiffness for spinal cord injuries

无动力储能式截瘫助行外骨骼为不同身高、体重和损伤情况的截瘫患者提供精准化助行，储能弹簧作为外骨骼标准元件，其刚度为固定值。该文针对该外骨骼储能弹簧刚度参数选择问题，建立了截瘫患者穿戴无动力储能式截瘫助行外骨骼单侧下肢从站立中期到站立后期动力学模型，得到人体髋关节力矩与身高、体重、髋关节角度的关系，并提出以人体髋关节和弹簧力矩之和绝对值的积分为优化目标的弹簧刚度参数优化设计方法。研究发现：不同身高、体重组合情况下，外骨骼弹簧1刚度k1满足正态分布，弹簧2刚度k2不满足正态分布；k1和k2的中位数3 180和1 279 N/m作为无动力储能式截瘫助行外骨骼储能弹簧刚度参数，适用于身高和体重在百分位数P1~P99间的患者。
Abstract：The unpowered energy-stored exoskeleton can provide precise walking assistance for spinal cord injury patients for a specified body height, weight and injury level. Since the energy-stored springs are standard components of the exoskeleton, their stiffness should be constant. The aim of this study is to select the optimal stiffness of the exoskeleton springs. The hip joint moment was related to the body height, body weight and hip joint angle through an inverse dynamics model for spinal cord injury patients walking in the single support phase from mid stance to terminal stance. The optimization method minimized the integral of the absolute moment generated by the hip joint and springs. The results show that the stiffness of spring 1 (k1) has a normal distribution while the stiffness of spring 2 (k2) does not. The medians of the two spring stiffnesses (the median k1=3 180 N/m and the median k2=1 279 N/m) can apply to patients whose heights and weights are in the P1-P99 ranges.