Department of Industrial and Systems Engineering, Auburn University, Auburn, AL 36849, USA.
Institute of Industry and Management, Universidad Austral de Chile, Puerto Montt 5480000, Chile.
Sensors (Basel). 2024 Mar 18;24(6):1941. doi: 10.3390/s24061941.
This study assesses the agreement of compressive and shear force estimates at the L5-S1 joint using inertial motion capture (IMC) within a musculoskeletal simulation model during manual lifting tasks, compared against a top-down optical motion capture (OMC)-based model. Thirty-six participants completed lifting and lowering tasks while wearing a modified Plug-in Gait marker set for the OMC and a full-body IMC set-up consisting of 17 sensors. The study focused on tasks with variable load weights, lifting heights, and trunk rotation angles. It was found that the IMC system consistently underestimated the compressive forces by an average of 34% (975.16 N) and the shear forces by 30% (291.77 N) compared with the OMC system. A critical observation was the discrepancy in joint angle measurements, particularly in trunk flexion, where the IMC-based model underestimated the angles by 10.92-11.19 degrees on average, with the extremes reaching up to 28 degrees. This underestimation was more pronounced in tasks involving greater flexion, notably impacting the force estimates. Additionally, this study highlights significant differences in the distance from the spine to the box during these tasks. On average, the IMC system showed an 8 cm shorter distance on the axis and a 12-13 cm shorter distance on the axis during lifting and lowering, respectively, indicating a consistent underestimation of the segment length compared with the OMC system. These discrepancies in the joint angles and distances suggest potential limitations of the IMC system's sensor placement and model scaling. The load weight emerged as the most significant factor affecting force estimates, particularly at lower lifting heights, which involved more pronounced flexion movements. This study concludes that while the IMC system offers utility in ergonomic assessments, sensor placement and anthropometric modeling accuracy enhancements are imperative for more reliable force and kinematic estimations in occupational settings.
本研究通过肌肉骨骼仿真模型内的惯性运动捕捉（IMC），评估在手动举升任务中 L5-S1 关节的压缩力和剪切力估计值与自上而下的光学运动捕捉（OMC）的一致性。36 名参与者在穿戴改良后的 Plug-in Gait 标记点 OMC 系统和包含 17 个传感器的全身 IMC 系统的情况下，完成了举升和降低任务。研究侧重于具有可变负载重量、举升高度和躯干旋转角度的任务。结果发现，与 OMC 系统相比，IMC 系统始终低估了压缩力 34%（975.16N），剪切力 30%（291.77N）。一个关键的观察结果是关节角度测量的差异，特别是在躯干弯曲方面，IMC 基于的模型平均低估了 10.92-11.19 度的角度，极端情况下甚至达到 28 度。这种低估在涉及更大弯曲度的任务中更为明显，对力的估计有重大影响。此外，本研究强调了在这些任务中脊柱到盒子的距离的显著差异。平均而言，IMC 系统在升降过程中在 轴上显示出 8cm 的较短距离，在 轴上显示出 12-13cm 的较短距离，表明与 OMC 系统相比，节段长度的估计值存在持续低估。关节角度和距离的这些差异表明 IMC 系统的传感器放置和模型缩放存在潜在局限性。负载重量是影响力估计的最重要因素，尤其是在较低的举升高度下，涉及更为明显的弯曲运动。本研究得出结论，尽管 IMC 系统在人体工程学评估中具有实用性，但在职业环境中进行更可靠的力和运动学估计，需要增强传感器放置和人体测量建模准确性。
