Department of Biomedical Engineering, CaseWestern Reserve University, Cleveland, OH 44106, USA.
IEEE Trans Biomed Eng. 2013 Jan;60(1):10-9. doi: 10.1109/TBME.2012.2218601. Epub 2012 Sep 12.
This study investigated the use of center of mass (COM) acceleration feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor feedback. The feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM acceleration was accurately estimated (>89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, feedback control of stimulation reduced UE loading by 33%. COM acceleration feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the feedback control system during functional reaching activity that is more indicative of activities of daily living.
本研究探讨了使用质心（COM）加速度反馈来改善功能性神经肌肉刺激控制系统的性能，以恢复完全性胸段脊髓损伤患者的站立功能。通过实验验证了线性关联肌肉刺激变化和 COM 加速度变化的方法，随后产生的数据用于创建由传感器反馈驱动的输入-输出映射。通过系统调整反馈增益，在抵抗外部姿势干扰的同时，减少施加到仪器支撑装置上的上肢（UE）负载。使用安装在骨盆和躯干上的两个加速度计的 3-D 输出，可以准确估计全身 COM 加速度（>89%的方差解释）。与临床上使用的恒定肌肉刺激相比，刺激的反馈控制降低了 33%的 UE 加载。COM 加速度反馈在构建站立神经假体方面具有优势，因为它为一个全局、动态变量提供了综合控制协同作用的基础，并且需要最小的仪器。未来的工作应包括在更能说明日常生活活动的功能性伸手活动期间调整和测试反馈控制系统。
