五连杆外骨骼助力系统行走步态模型能量补偿

Energy compensation of a five-link walking exoskeleton model

人体行走过程包括支撑和摆动两相,脚后跟触地改变系统几何拓扑,使得步态变化不可导。外骨骼助力系统正常工作时运动状态与人体步态一致。文中运用位移激励法建立了一个支撑相过程中由驱动方程和约束方程组成的外骨骼行走步态模型拉格朗日方程组,通过三维捕捉系统确定人体不同负载下行走步态,通过方程组逆求解求得广义驱动力。脚跟触地导致系统能量损失,运用运动数据相空间分解方法分离出损失部分动能。理论计算出单腿支撑行走过程系统功率补偿密度和脚后跟触地瞬间动能损失,绘出各关节驱动功率时程变化曲线并对关节驱动器设计做了探讨。

Exoskeleton is a multi-body system whose kinematics can be described by Lagrange equations and is synchronous with human gait.System topology changes when the heel strikes,making the gait non-derivable.Lagrange equations of a walking exoskeleton model made up of both imposed and constrained ones,were established by displacement excitation method.The walking gait under different loads was captured by 3D caption system and used as driving items to get generalized forces by inverse-solving of Lagrange equations.Both the power compensation on stance phase and energy loss on heel strikes were calculated.Timing of power supply was then calculated,and the driver selection for each joint was also discussed.