假肢接受腔是连接残肢和假肢的关键部件,假肢接受腔的定制质量和残疾人的体验直接相关。针对假肢接受腔定制中取模精度不高,修型依赖假肢技师经验等问题,在分析残肢表面特征的基础上,提出了残肢表面三维重建算法和接受腔修型方法。通过...假肢接受腔是连接残肢和假肢的关键部件,假肢接受腔的定制质量和残疾人的体验直接相关。针对假肢接受腔定制中取模精度不高,修型依赖假肢技师经验等问题,在分析残肢表面特征的基础上,提出了残肢表面三维重建算法和接受腔修型方法。通过深度相机扫描残肢,计算残肢点云数据的快速点特征直方图(FPFH)特征,应用采样一致性初始配准(SAC-IA)算法和迭代最近点(ICP)算法分别实现了点云初始配准和精确配准,基于仿射变换的特性提升了点云配准精度,实现残肢表面高精度重建。通过有限元仿真分析了大腿残肢-接受腔系统的受力情况,得出残肢几何形状规则时普遍的正应力和剪切力分布情况,与假肢技师经验平台相结合提出了修型建议,应用3D打印技术实现了接受腔快速成型。实验与仿真表明,三维重建均方误差仅有2. 1 mm,接受腔修型方法可以与医师经验平台互补,应力最大可减少34 k Pa。展开更多
The dynamic effects of inertial loads on the interface stresses between a residual limb and the trans-tibial prosthetic socket were investigated. A 3-D nonlinear finite element model, based on the actual geometry of t...The dynamic effects of inertial loads on the interface stresses between a residual limb and the trans-tibial prosthetic socket were investigated. A 3-D nonlinear finite element model, based on the actual geometry of the residual limb, including internal bones and socket liner, was developed to study the mechanical interaction between the socket and the residual limb during walking. To simulate the friction/slip boundary conditions between the skin and liner, automated surface-to-surface contact was used. The results show that interface pressure and shear stress have a similar double-peaked waveform shape in the stance phase. The average difference in interface stresses between the cases with and without consideration of inertial forces is 8.4% in the stance phase and 20.1% in the swing phase. The results suggest that the dynamic effects of inertial loads on interface stress distribution during walking must be considered in prosthetic socket design.展开更多
To help comfort for an amputee, it is important to understand the load distribution between the residual limb and the prosthetic socket for a prosthetic socket system. An interfacial stress sensor was presented which ...To help comfort for an amputee, it is important to understand the load distribution between the residual limb and the prosthetic socket for a prosthetic socket system. An interfacial stress sensor was presented which was capable of measuring compressive pressure and shear stress simultaneously. A mathematical model was built and an experiment was conducted to obtain the transfer function of interfacial stress sensor to compressive pressure. The results show that the sensor is capable of measuring a range of 30-217 kPa compressive pressure with a relative error of 32.15% in lower range and 6.22% in upper range.展开更多
文摘假肢接受腔是连接残肢和假肢的关键部件,假肢接受腔的定制质量和残疾人的体验直接相关。针对假肢接受腔定制中取模精度不高,修型依赖假肢技师经验等问题,在分析残肢表面特征的基础上,提出了残肢表面三维重建算法和接受腔修型方法。通过深度相机扫描残肢,计算残肢点云数据的快速点特征直方图(FPFH)特征,应用采样一致性初始配准(SAC-IA)算法和迭代最近点(ICP)算法分别实现了点云初始配准和精确配准,基于仿射变换的特性提升了点云配准精度,实现残肢表面高精度重建。通过有限元仿真分析了大腿残肢-接受腔系统的受力情况,得出残肢几何形状规则时普遍的正应力和剪切力分布情况,与假肢技师经验平台相结合提出了修型建议,应用3D打印技术实现了接受腔快速成型。实验与仿真表明,三维重建均方误差仅有2. 1 mm,接受腔修型方法可以与医师经验平台互补,应力最大可减少34 k Pa。
文摘The dynamic effects of inertial loads on the interface stresses between a residual limb and the trans-tibial prosthetic socket were investigated. A 3-D nonlinear finite element model, based on the actual geometry of the residual limb, including internal bones and socket liner, was developed to study the mechanical interaction between the socket and the residual limb during walking. To simulate the friction/slip boundary conditions between the skin and liner, automated surface-to-surface contact was used. The results show that interface pressure and shear stress have a similar double-peaked waveform shape in the stance phase. The average difference in interface stresses between the cases with and without consideration of inertial forces is 8.4% in the stance phase and 20.1% in the swing phase. The results suggest that the dynamic effects of inertial loads on interface stress distribution during walking must be considered in prosthetic socket design.
文摘利用断层扫描数据,图像处理和反求技术建立了骨骼、软组织以及假肢接受腔的三维有限元模型,分别施加Heel Strike、Foot Flat、Mid-Stance、Heel Off和Toe Off五个典型步态时相的载荷,计算残肢皮肤在一个步态周期内的应力、滑移量变化,确定最大临界参数;借助UMT-II多功能摩擦磨损试验机模拟残肢皮肤和接受腔摩擦界面,研究皮肤在步态周期临界参数下的摩擦行为变化.有限元结果表明:一个步态周期内五个典型时相,软组织表面最大正应力和剪切力均发生在髌韧带处,在Heel off步态时相,最大临界正应力为384.3 k Pa,剪应力为102.1 k Pa;随着正压力的减小,摩擦力减小,摩擦系数增大;当正应力下降到39.5 k Pa临界值时,接触面发生相对滑动,摩擦系数达到最大值.摩擦学试验结果表明:法向载荷分别为17 N和7 N时,残肢皮肤均处于黏着状态;皮肤弹性变形越大,黏着程度越大.
基金National Natural Science Foundations of China(No.60976058,No.61274078)Innovation Program of Shanghai Municipal Education Commission,China(No.13ZZ049)Fundamental Research Funds for the Central Universities of Xidian University,China(No.K5051304005)
文摘To help comfort for an amputee, it is important to understand the load distribution between the residual limb and the prosthetic socket for a prosthetic socket system. An interfacial stress sensor was presented which was capable of measuring compressive pressure and shear stress simultaneously. A mathematical model was built and an experiment was conducted to obtain the transfer function of interfacial stress sensor to compressive pressure. The results show that the sensor is capable of measuring a range of 30-217 kPa compressive pressure with a relative error of 32.15% in lower range and 6.22% in upper range.
