Automatic determination of the transition between successive control mechanisms in upright stance assessed by modelling of the centre of pressure.
Automatic determination of the transition between successive control mechanisms in upright stance assessed by modelling of the centre of pressure.
复制标题
通过压力中心建模来自动确定直立姿态下连续控制机制之间的过渡。
DOI：
10.1076/apab.107.1.35.4350
复制
发表时间：
1999
影响因子：
3
通讯作者：
P. Rougier
中科院分区：
文献类型：
--
作者：
P. Rougier
最近推出的概念模型的轨迹的压力中心作为一个分数布朗运动，并揭示了两个连续的缩放制度，假设作为开环和闭环机制，牵连在姿态控制。显然，在确定转换点时需要客观性，即开环控制机制将切换到闭环控制机制的点，以便在数据处理中提供可再现性和自动性。在本文提出的方法中，转变点对应于将双对数图中的扩散曲线（在每个轴上计算的均方距离MSD相对于增加的时间间隔Δ t）与表征纯随机行为的直线分开的最大距离。在闭上眼睛的条件下，开关出现在0。26-0.52 s范围内，相应的MSD范围为1.86-10.50 mm（2）。在前后方向上，过渡在0.28-0.42 s范围内，相应的MSD在3.60和15.17 mm（2）之间。最后，这些坐标诱导标度指数超过0.50的最短的Δ t，从而表明开环控制，而那些最长的Δ t，范围在0和0.20之间，给出闭环控制的证据。将该数据与基于经验方法的先前数据进行比较。
A recently introduced concept models the trajectory of the centre of pressure as a fractional Brownian motion and reveals that two successive scaling regimes, acting hypothetically as open and closed loop mechanisms, are implicated in posture control. Objectivity is obviously required in the determination of the transition point, i.e. the point at which an open-loop control mechanism would switch to a closed-loop one, in order to provide reproducibility and automatism in the processing of data. In the method proposed herein, the transition point corresponds to the maximal distance separating a diffusion curve in a double logarithmic plot (mean square distances MSD calculated on each axis versus increasing time intervals Deltat) from a straight line characterising a pure stochastic behaviour. In closed eye conditions, the switch appears medio-laterally in a 0. 26-0.52 s range for Deltat, the corresponding MSD being in the range of 1.86-10.50 mm(2). In the forward-backward direction, the transition is in a 0.28-0.42 s range and the corresponding MSD is between 3.60 and 15.17 mm(2). Finally, these co-ordinates induce scaling exponents over 0.50 for the shortest Deltat, thus suggesting open-loop control, whereas those of longest Deltat, ranged between 0 and 0.20, give evidence of close-loop control. This data is compared to previous data based upon empirical methods.