基于Stewart平台与sEMG的特定运动轨迹下肌肉激活模式分析

Analysis of Muscle Activation Patterns under Specific Motion Trajectories Based on a Stewart Platform and sEMG

摘要: 平衡控制依赖下肢多肌群的协同活动，揭示其在多维扰动下的响应模式对康复训练与跌倒预防具有重要意义。本研究基于Stewart六自由度平台的逆运动学计算，设计了五种典型扰动轨迹，分别为沿X向加速、沿Y向加速、绕X轴正弦翻转、绕Y轴正弦翻转及俯仰翻滚。健康受试者在平台上完成任务，采用Noraxon-DTS无线表面肌电系统采集比目鱼肌、腓肠肌内侧、胫骨前肌、股二头肌和股四头肌的sEMG信号。信号经过去均值、带通滤波、全波整流和平滑处理，提取均方根值(RMS)和积分肌电(iEMG)作为指标。结果表明：矢状面扰动主要激活小腿远端肌群，额状面扰动则以大腿肌群为主，翻转扰动下腓肠肌内侧反应显著，而复合扰动表现为多肌群协同增强。结论认为，基于逆运动学驱动的Stewart平台结合sEMG分析，可有效揭示下肢在多维扰动下的肌肉响应规律，为康复训练和运动控制研究提供参考。

Abstract: Balance control relies on the coordinated activity of multiple lower-limb muscles, and revealing their response patterns under multidimensional perturbations is of great importance for rehabilitation training and fall prevention. In this study, five representative perturbation trajectories were designed based on the inverse kinematic calculations of a Stewart six-degree-of-freedom platform, including acceleration along the X-axis, acceleration along the Y-axis, sinusoidal rotation about the X-axis, sinusoidal rotation about the Y-axis, and combined pitch-roll motion. Healthy participants performed tasks on the platform, while surface electromyography (sEMG) signals of the soleus, medial gastrocnemius, tibialis anterior, biceps femoris, and quadriceps femoris were recorded using the Noraxon-DTS wireless system. The signals were processed through demeaning, band-pass filtering, full-wave rectification, and smoothing, with root mean square (RMS) and integrated EMG (iEMG) extracted as key indicators. Results showed that sagittal perturbations primarily activated distal lower-leg muscles, frontal perturbations mainly engaged thigh muscles, medial gastrocnemius exhibited a pronounced response under rotational perturbations, and combined perturbations induced enhanced multi-muscle synergies. In conclusion, the Stewart platform, driven by inverse kinematic control, combined with sEMG analysis, provides an effective approach to reveal lower-limb muscle response patterns under multidimensional perturbations, offering valuable insights for rehabilitation training and motor control research.