Abstract: To promote the high energy consumption of traditional rigid foot robot movement,the relationship between stiffness and energy efficiency was summarized with bionics,and a mathematical model of series connected flexible single leg with active and passive variable stiffness was established,which described the reducer,flexible joint damping and power flow in detail.The key parameters of single leg model were selected and combined with the bionics to design the passive variable stiffness of joint's three section line.The ground and joint collision simulation was made through Hertz model,which verified the better stability of flexible single leg with passive variable stiffness by comparing to flexible single leg with active variable stiffness.Based on the simulation of two processes that were jumping in place and horizontal motion in support phase,the variation law between stiffness and energy consumption under different conditions was obtained.The active and passive variable stiffness flexible joint and the single leg prototype based on this joint were developed,and the experiment by combining with NI-cRIO system showed that the energy consumption of legged robot under different motion conditions could be optimized by adjusting the stiffness coefficient properly,which agreeed with the bionics study.

Key words: flexible joint, active variable stiffness, passive variable stiffness, flexible single leg, bionics

摘要： 为了改善传统刚性足式机器人运动高能耗问题,通过仿生学研究总结人类跑跳运动刚度与能效相关性,建立具有主—被动复合变刚度的串联柔性单腿数学模型,对减速器、柔性关节阻尼、功率流进行了详细描述;选定单腿模型主要参数并结合仿生学设计关节“三段式”被动变刚度特性,采用Hertz模型进行触地碰撞仿真,验证了具有被动变刚度特性的柔性单腿比定刚度柔性单腿具有更好的稳定性;通过对原地跳跃运动、支撑相水平运动两个过程的仿真计算,得出不同运动情况下腿部刚度与能耗的变化规律。研制了具有主—被动复合式变刚度柔性关节及基于该关节的单腿样机,联合NI-cRIO系统实验,验证了不同运动情况下合理调整刚度系数能够改善足式机器人能耗的结论,与仿生学研究相符。

关键词: 柔性关节, 主动变刚度, 被动变刚度, 柔性单腿, 仿生学