Contact Modelling for Forward Dynamics of Human Motion
Contact Modelling for Forward Dynamics of Human Motion
复制标题
人体运动前向动力学的接触建模
DOI：
--
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Peter Brown
中科院分区：
文献类型：
--
作者：
Peter Brown
人体的多体前向动力学模型常用于人体运动的预测仿真。这些模型的一个重要组成部分是接触建模。例如，脚-地面接触在从步行或跑步模拟获得准确结果方面起着至关重要的作用，并且关节的接触模型对于确定准确的关节压力是必要的。接触模型增加了多体系统方程的复杂性（通常是显着的），并可以引入非线性和不连续的系统方程。这在预测模拟中尤其成问题，预测模拟可以通过运行数千次模型模拟来确定最佳性能。理想的接触模型应该足够精确以重新创建生理运动和接触压力，但仍然足够有效以用于优化。多体生物力学的一个合适的接触模型是体积接触建模。体积接触建模非常适合于大的、一致的接触，如在生物力学应用中所发现的，并且具有相对简单的分析方程（假设接触表面可以近似为简化形状）。另一个优点是，体积接触可以用来计算接触压力，这是很难做到与简单的点接触模型。在本论文中，体积接触被用于两个生物力学模型来测试其适用性：胫股接触的解剖膝关节模型和脚-地面接触模型。膝关节体积模型基于文献中的另一个膝关节模型，其中接触模型被体积接触替代。体积模型的运行速度比实时模型快，接触力与原始模型相似。通过使用医学图像来确定接触几何形状并在模型中包括肌肉，可以进行进一步的改进。摩擦力模型是某些生物力学接触模型的重要组成部分，特别是脚-地面接触模型。文献回顾表明，许多当前的摩擦模型引入不连续系统方程或不必要的复杂。提出了一种新的连续摩擦模型，该模型使用最少的参数，便于参数化。一种新的，三维的脚-地面接触模型的开发和验证，为未来使用的人类步态模拟。足部模型使用椭球体几何形状的体积接触方程（这是在本论文中推导的，作为对以前的球-平面接触模型的改进）。步态实验用于参数化和验证模型（摩擦参数除外）。该模型的运行速度比实时（在逆模拟中）快100倍以上，并与实验法向力和压力中心位置相匹配（均方根误差小于7%）。结果发现，设计的步态实验不能用于确定摩擦参数的脚-地面模型。提出了一个可能的替代方案，模型摩擦部分的验证留待今后研究。总之，体积接触可用于产生计算高效且准确的接触模型。
Multibody forward dynamics models of the human body are often used in predictive simulations of human motion. An important component of these models is contact modelling. For example, foot-ground contact plays a crucial role in obtaining accurate results from a walking or running simulation and contact models of joints are necessary to determine accurate joint pressures. Contact models increase multibody system equation complexity (often dramatically) and can introduce nonlinearities and discontinuities into the system equations. This is particularly problematic in predictive simulations, which may determine optimal performance by running a model simulation thousands of times. A desirable contact model should be accurate enough to recreate physiological motion and contact pressures yet still efficient enough to use in an optimisation. A suitable contact model for multibody biomechanics is volumetric contact modelling. Volumetric contact modelling is ideally suited for large, conforming contacts, as is found in biomechanic applications, and has relatively simple, analytical equations (provided the contact surfaces can be approximated as simplified shapes). Another advantage is that volumetric contact can be used to calculate contact pressure, which is difficult to do with simpler point-contact models. In this thesis, volumetric contact was used in two biomechanics models to test its applicability: an anatomical knee model with tibiofemoral contact and a foot-ground contact model. The volumetric knee model was based on another knee model in the literature, with the contact model replaced with volumetric contact. The volumetric model ran faster than real-time and had similar contact forces to the original model. Further improvements are possible by using medical images to determine the contact geometry and including muscles in the model. A friction model is an important part of some biomechanic contact models, particularly the foot-ground contact model. A literature review revealed that many current friction models introduce discontinuities into system equations or are unnecessarily complex. A novel continuous friction model was developed which uses a minimum number of parameters for easy parametrisation. A novel, three-dimensional foot-ground contact model was developed and validated, for future use in a human gait simulation. The foot model used volumetric contact equations for ellipsoidal geometry (which were derived in this thesis, as an improvement on previous sphere-plane contact models). A gait experiment was used to parametrise and validate the model (except for the friction parameters). The model ran over 100 times faster than real-time (in an inverse simulation) and matched experimental normal force and centre of pressure location (with less than 7% root-mean-square error). It was discovered that the designed gait experiment could not be used to determine the friction parameters for the foot-ground model. A possible alternative was suggested, and the validation of the friction portion of the model was left to a future study. In conclusion, volumetric contact can be used to produce a computationally efficient and accurate contact model.
影响因子：
2.4
作者：
Gerus P;Sartori M;Besier TF;Fregly BJ;Delp SL;Banks SA;Pandy MG;D'Lima DD;Lloyd DG
通讯作者：
Lloyd DG
影响因子：
2.4
作者：
Halloran, Jason P.;Ackermann, Marko;Erdemir, Ahmet;van den Bogert, Antonie J.
通讯作者：
van den Bogert, Antonie J.
DOI：
10.1115/1.4032464
发表时间：
2016-02-01
影响因子：
1.7
作者：
Smith, Colin R.;Vignos, Michael F.;Thelen, Darryl G.
通讯作者：
Thelen, Darryl G.