arXiv:2606.04222cs.RO2026-06

用物理模型估算假肢接口的正压与剪切压,提升适配评估客观性。

Towards Estimating Normal and Shear Interface Pressures in Prosthetic Sockets via Least Squares and Mechanics Modeling

论文配图:Towards Estimating Normal and Shear Interface Pressures in Prosthetic Sockets via Least Squares and Mechanics Modeling
图 1 · 摘自论文原文
  • 结合全局受力和局部传感数据,通过最小二乘法优化机械模型参数。
  • 加入恒定偏置项后,全局受力误差降低,局部压力匹配度提升。
  • 适合假肢设计、康复工程领域研究者参考,尤其关注接口力学分析者。

假肢插座适配仍以人工经验为主,缺乏客观评价指标。主要难点在于长期真实环境下残肢-插座界面的压力数据不足。传统压力传感器易漂移,且仅能捕捉稀疏位置的法向压力,遗漏关键的剪切力信息。尽管部分传感器可同时测量法向与剪切应力,但因测量串扰难以解耦。本文提出一种测试平台,用于在稀疏传感条件下评估模型性能,采用两种互补验证信号:(i) 通过人工残肢传递的全局力矩(即总力与力矩,表示于正交坐标系中);(ii) 局部界面载荷(即每个传感器阵列点处解耦的法向与剪切分量,采用右手坐标系)。重点不在于全场压力估计,而是分析候选力学模型在受控条件下对全局与局部测量的解释能力。评估了一种准静态弹簧-质量接触模型,其参数通过两阶段凸最小二乘问题求解。静态加载验证表明,引入常数偏置项可有效减少力矩通道的稳态偏差,并改善与局部测量的一致性。帕累托前沿敏感性分析进一步揭示,包含偏置项时,全局与局部目标间的权衡关系发生变化。

原文摘要 · Abstract (English)

Prosthetic socket fitting remains largely manual and iterative, and objective fit metrics are still limited. Part of the challenge is the lack of long-term real-life pressure data at the residual limb--socket interface. Traditional pressure sensors are prone to drift over time, and capture only normal pressures at sparse locations within the socket, missing a critical component for biomechanical analysis: shear. Although some sensors can report both normal and shear interface stresses, these components are often difficult to decouple because of measurement crosstalk. One potential path forward is to develop models that can augment available measurements. This work introduces a testbed to evaluate model performance under sparse pressure sensing using two complementary validation signals: (i) the global wrench (\ie, total forces and moments expressed in an orthonormal frame) transmitted through the socket, by an artificial residual-limb, and (ii) local interface loads (\ie, decoupled normal and shear pressure components in a right-hand-rule orthogonal frame that lives in each instrumented location) measured by sparse sensing clusters, each composed of four capacitance-sensing channels. Rather than presenting full-field pressure estimates, the focus is on an analysis sequence that quantifies how well candidate mechanical models explain both global and local measurements under controlled conditions. A quasi-static spring--mass contact model is evaluated, and its parameters are identified via a two-stage convex least-squares problem. Validation under static loading shows that estimating constant bias terms reduces steady offsets in the wrench channels and improves agreement with local measurements. A Pareto-front sensitivity analysis further illustrates how the trade-off between global and local objectives changes when bias terms are included.

假肢接口力学建模压力估计

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