Park Jaeheung
Stanford Artificial Intelligence Laboratory, Department of Computer Science, Stanford University, Stanford, CA 94305, USA.
J Biomech. 2008;41(7):1417-26. doi: 10.1016/j.jbiomech.2008.02.031. Epub 2008 Apr 15.
It has historically been believed that the role of arm motion during walking is related to balancing. Arm motion during natural walking is distinguished in that each arm swing is with the motion of the opposing leg. Although this arm swing motion is generated naturally during bipedal walking, it is interesting to note that the arm swing motion is not necessary for stable walking. This paper attempts to explain the contribution of out-of-phase arm swing in human bipedal walking. Consequently, a human motion control methodology that generates this arm swing motion during walking is proposed. The relationship between arm swing and reaction moment about the vertical axis of the foot is explained in the context of the dynamics of a multi-body articulated system. From this understanding, it is reasoned that arm swing is the result of an effort to reduce the reaction moment about the vertical axis of the foot while the torso and legs are being controlled. This idea is applied to the generation of walking motion. The arm swing motion can be generated, not by designing and tracking joint trajectories of the arms, but by limiting the allowable reaction moment at the foot and minimizing whole-body motion while controlling the lower limbs and torso to follow the designed trajectory. Simulation results, first with the constraint on the foot vertical axis moment and then without, verify the relationship between arm swing and foot reaction moment. These results also demonstrate the use of the dynamic control method in generating arm swing motion.
历史上人们一直认为，行走过程中手臂运动的作用与平衡有关。自然行走时的手臂运动特点是，每一次手臂摆动都与相对的腿部运动同步。虽然这种手臂摆动运动在双足行走过程中是自然产生的，但值得注意的是，稳定行走并不一定需要手臂摆动运动。本文试图解释异相手臂摆动在人类双足行走中的作用。因此，提出了一种在行走过程中产生这种手臂摆动运动的人体运动控制方法。在多体关节系统动力学的背景下，解释了手臂摆动与足部垂直轴反应力矩之间的关系。基于这种理解，可以推断出，手臂摆动是在控制躯干和腿部时，为了减少足部垂直轴反应力矩而做出的努力的结果。这一观点被应用于行走运动的生成。手臂摆动运动的产生，不是通过设计和跟踪手臂的关节轨迹，而是通过限制足部的允许反应力矩，并在控制下肢和躯干以遵循设计轨迹的同时，使全身运动最小化。仿真结果首先在足部垂直轴力矩受限的情况下，然后在不受限的情况下，验证了手臂摆动与足部反应力矩之间的关系。这些结果也证明了动态控制方法在生成手臂摆动运动中的应用。
