基于能量的人体动力学平衡评价指标的仿真研究

Energy based criterion for dynamic balance of human body

了解人体平衡机理 ,对人的疾病诊断和康复有重要意义。提出了一种基于能量分析的人体动力学稳定区域的评价指标。以人体两刚体倒立摆模型为例 ,利用优化方法 ,计算了其动力学稳定区域的前后边界 ,分析了动力学稳定区域与肢体动力学特征之间的能量关系。该方法更适合人体质心有较大位移及速度运动时的稳定性分析。分析了人体踝关节力矩对其稳定区域的影响。仿真结果表明 :踝关节力矩的减弱会导致稳定区域的明显减少 ,而且对稳定区域前边界的影响较后边界更明显 ,即踝关节肌肉力矩的减弱会导致更多的向前跨步来保持平衡。

An energy based criterion for dynamic balance of human body is presented. As an example, two segment model of human body, an inverted pendulum model, is employed to map the anterior and posterior boundaries of stability region with optimization algorithm, then the energy relationship between the dynamic characteristic of body and dynamic stability region is examined. It can be employed to predict the dynamic stability of human locomotion when a large displacement or velocity of mass center has occurred. In addition, the influence of reduction of muscle strength on the stability margin has been analyzed by computer simulation. The results show that the reduction of ankle muscle strength results in apparent decrease of stability region. And also, more reductions have been found on anterior boundary of stability region than posterior boundary, e.g., subject with a reduction of ankle muscle strength prefers to take forward step to keep balance than the normal. The results agree well with the clinical observation of balance pattern of the older, who prefer to take steps to keep balance than the young even on a small disturbance.