Riener R, Quintern J, Schmidt G
Laboratory for Automatic Control Engineering, Technical University of Munich, Germany.
J Biomech. 1996 Sep;29(9):1157-67. doi: 10.1016/0021-9290(96)00012-7.
A detailed model of the human knee was developed to predict shank motion induced by functional neuromuscular stimulation (FNS). A discrete-time model is used to characterize the relationship between stimulus parameters and muscle activation. A Hill-based model of the musculotendon actuator accounts for nonlinear static and dynamic properties of both muscle and tendon. Muscle fatigue and passive muscle viscosity are modeled in detail. Moment arms are computed from musculotendon paths of 13 actuators and from joint geometry. The model also takes nonlinear body-segmental dynamics into consideration. The simulated motion is visualized by graphic animation. Individual model parameters were identified by specific procedures such as anthropometric measurements, a passive pendulum test, and specific open-loop stimulation experiments. Model results were compared with experimental data obtained by stimulating the quadriceps muscle of paraplegic patients with surface electrodes. The knee moment, under isometric conditions, and the knee angle, under conditions of freely swinging shank, were measured. In view of the good correspondence obtained between model predictions and experimental data, we conclude that a biomechanical model of human motion induced by FNS can be used as a mathematical tool to support and accelerate the development of neural prostheses.
为预测功能性神经肌肉刺激（FNS）引起的小腿运动，构建了一个详细的人体膝关节模型。采用离散时间模型来描述刺激参数与肌肉激活之间的关系。基于希尔模型的肌肉肌腱驱动器考虑了肌肉和肌腱的非线性静态和动态特性。详细模拟了肌肉疲劳和被动肌肉粘性。根据13个驱动器的肌肉肌腱路径和关节几何形状计算出力臂。该模型还考虑了非线性的身体节段动力学。通过图形动画展示模拟运动。通过人体测量、被动摆测试和特定的开环刺激实验等特定程序确定了各个模型参数。将模型结果与通过表面电极刺激截瘫患者股四头肌获得的实验数据进行了比较。测量了等长条件下的膝关节力矩和小腿自由摆动条件下的膝关节角度。鉴于模型预测与实验数据之间具有良好的一致性，我们得出结论，FNS引起的人体运动生物力学模型可作为一种数学工具，以支持和加速神经假体的开发。
