Passive stability and active control in a rhythmic task.
Passive stability and active control in a rhythmic task.
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DOI：
10.1152/jn.00742.2007
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发表时间：
2007-11
影响因子：
2.5
通讯作者：
Kunlin Wei;T. Dijkstra;D. Sternad
中科院分区：
文献类型：
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作者：
Kunlin Wei;T. Dijkstra;D. Sternad
用球拍有节奏地拍球是一项提供被动稳定解决方案的任务，如该任务的数学模型的稳定性分析所示。被动稳定性意味着不需要主动控制，因为错误消失而不需要纠正措施。人类表现的实证结果表明，演员确实利用这种被动的动态稳定状态的性能，从而减少计算的任务的要求。本研究调查的响应设计的基础上，该模型的吸引盆不同幅度的扰动。人类在具有触觉界面的虚拟现实设置中执行任务。松弛时间的性能错误显示出显着更快的回报比预测从纯粹的被动模型，主动纠错的指示。球拍轨迹的系统适应是扰动幅度的单调函数，表明主动控制与扰动成比例。这些结果并不表明对稳定性边界有任何敏感性。然而，被动动力学的影响也被看到：在主要性能变量球高度的松弛时间的模式是一致的定性预测来自盆地的吸引力和球拍接触时的加速度一般是消极的信号使用的被动稳定性。这些发现表明，任务的被动特性有助于快速返回稳定状态。得出的结论是，行为者对各种大小的扰动使用了主动和被动控制的混合。
Rhythmically bouncing a ball with a racket is a task that affords passively stable solutions as demonstrated by stability analyses of a mathematical model of the task. Passive stability implies that no active control is needed as errors die out without requiring corrective actions. Empirical results from human performance demonstrated that actors indeed exploit this passive dynamics in steady-state performance, thereby reducing computational demands of the task. The present study investigated the response to perturbations of different magnitudes designed on the basis of the model's basin of attraction. Humans performed the task in a virtual reality set-up with a haptic interface. Relaxation times of the performance errors showed significantly faster returns than predicted from the purely passive model, indicative of active error corrections. Systematic adaptations in the racket trajectories were a monotonic function of the perturbation magnitudes, indicating that active control was applied in proportion to the perturbation. These results did not indicate any sensitivity to the boundary of stability. Yet the influence of passive dynamics was also seen: the pattern of relaxation times in the major performance variable ball height was consistent with qualitative predictions derived from the basin of attraction and racket accelerations at contact were generally negative signaling use of passive stability. These findings suggest that the fast return back to steady state was assisted by passive properties of the task. It was concluded that actors used a blend of active and passive control for all sizes of perturbations.