Impedance control balances stability with metabolically costly muscle activation
Impedance control balances stability with metabolically costly muscle activation
复制标题
DOI：
10.1152/jn.00364.2004
复制
发表时间：
2004-11-01
影响因子：
2.5
通讯作者：
Milner, TE
中科院分区：
文献类型：
--
作者：
Franklin, DW;So, U;Milner, TE
人类能够在不稳定的动态环境中通过选择性地改变手臂阻抗来稳定他们的运动，而不受力和扭矩的影响。我们进一步研究了对不稳定动态的适应，以确定当环境动态的不稳定性变化时，中枢神经系统是否保持恒定的整体稳定水平。受试者在由机器人操纵器产生的不同强度的不稳定力场中进行伸展运动。尽管力场扰乱了最初的运动，但受试者能够适应新的动力学并学会产生直线轨迹。适应后，在运动中点测量手臂的端点刚度。在失稳方向上对刚度进行了选择性修正。稳定方向的刚度相对于暴露于不稳定力场之前在零力场中运动时测量的刚度不变。这种阻抗改变是在不改变力和扭矩的情况下实现的。手臂的整体刚度和不稳定方向上的环境与力场强度相适应，使其保持与零力场的等效。这表明中枢神经系统既试图维持最低水平的稳定性，又尽量减少能量消耗。
Humans are able to stabilize their movements in environments with unstable dynamics by selectively modifying arm impedance independently of force and torque. We further investigated adaptation to unstable dynamics to determine whether the CNS maintains a constant overall level of stability as the instability of the environmental dynamics is varied. Subjects performed reaching movements in unstable force fields of varying strength, generated by a robotic manipulator. Although the force fields disrupted the initial movements, subjects were able to adapt to the novel dynamics and learned to produce straight trajectories. After adaptation, the endpoint stiffness of the arm was measured at the midpoint of the movement. The stiffness had been selectively modified in the direction of the instability. The stiffness in the stable direction was relatively unchanged from that measured during movements in a null force field prior to exposure to the unstable force field. This impedance modification was achieved without changes in force and torque. The overall stiffness of the arm and environment in the direction of instability was adapted to the force field strength such that it remained equivalent to that of the null force field. This suggests that the CNS attempts both to maintain a minimum level of stability and minimize energy expenditure.