Mathematical Modeling and Simulation of Seated Stability

摘要: Abstract Various methods have been used to quantify the kinematic variability or stability of human spine. However, each these evaluates dynamic behavior within stable region state space. In contrast, our goal was determine extent region. A 2D mathematical model developed for a sitting on an unstable seat apparatus (i.e., “wobble chair”). Forward simulations were compute trajectories based initial state. From trajectories, scalar field trajectory divergence calculated, specifically finite time Lyapunov exponent (FTLE) field. Theoretically, ridges local maxima this are expected partition space into regions qualitatively different behavior. We found that formed at boundary between and failure falling). The location basin using FTLE matched well with determined by alternative method. addition, equilibrium manifold found, which describes set configurations act as low dimensional attractor in controlled system. These first step developing method locate boundaries torso stability. Identifying may provide framework assessing factors contribute health risks associated spinal injury poor balance recovery (e.g., age, fatigue, load/weight, distribution). Furthermore, approach is presented can be adapted find other biomechanical applications.