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1.
介绍了基于光切法的全三维量脚制鞋系统。利用基于光切法的三维形貌扫描仪对足型进行测量,得到精度为±0.4mm的足型数据。根据足部关键参数,选择标准鞋楦。将脚型划分为多个特征段,足型数据和标准鞋楦的规则化点云拟合为NURBS曲线,各段内根据脚型的特点对标准鞋楦进行整体缩放以局部修改,利用能量优化原则同时修改控制点和权因子,对标准鞋楦进行修改,使其符合脚型的整体三维特点。定制鞋楦建模后,利用等距面法得到鞋楦的刀具加工轨迹并转化为通用格式的NC代码送入数据刻楦机进行加工,定制的鞋楦用于生产适合脚型的鞋子。该系统打破了根据有限的足部参数来选鞋的传统,真正实现了基于全三维足型数据的量脚制鞋。  相似文献   

2.
基于网格简化的参数化方法   总被引:2,自引:0,他引:2  
提出一种基于网格简化的三角网格参数化方法,该方法通过构建并参数化边界三角网格来自动完成复杂三角网格边界的参数化,然后通过一系列局部计算完成网格内部点的参数化.采用该方法得到的参数值可较好地反映三角网格的特性,而且计算具有较高的效率.  相似文献   

3.
基于点的鞋楦CAD/CAM技术   总被引:4,自引:1,他引:4  
提出了实用的基于点的鞋楦CAD/CAM技术,给出了基于点的鞋楦几何模型定义,由经过规则化处理的鞋楦表面数据点集表示鞋楦模型;在此基础上研究了鞋楦CAD方法,通过对点集的操作完成鞋楦设计;实现了鞋楦数控编程,建立刀具模型并给出刀位点计算的详细过程.该技术已经成功地用于鞋楦CAD/CAM系统的开发,并用于实际生产,完成鞋楦的高效设计与制造。  相似文献   

4.
网格模型的局部编辑算法   总被引:2,自引:3,他引:2  
提出一种新的网格模型局部编辑算法,该算法可以精确地控制变形区域的大小、边界和变形点的位移,克服了FFD及其改进算法的缺点.首先交互地定义一个附着在模型表面的控制网格;然后建立模型变形区域与控制网格间点的映射,再依据变形要求来编辑控制网格;最后根据映射关系反算出模型变形区域点的新位置.控制网格可以是参数曲面的控制网格,也可采用一般三角网格或预先定义的网格模板.为达到精确变形的目的,对模型与控制网格重叠的区域进行自适应细分.该算法计算简便、易于实现,并能达到很好的效果.  相似文献   

5.
服装CAD中三维人体模型的参数化研究   总被引:12,自引:0,他引:12  
针对三角网格曲面表示的3D人体模型缺少语义信息,提出一种3D人体模型的参数化方法:首先通过三角面片求交的采样策略得到采样点,然后使用B样条曲线构造人体轮廓线,最后由用户交互得到3D人体模型的参数化信息,建立3D人体模型的参数化模板.这样,在参数化人体模型模板的基础上,可以根据用户所输入的特定人体参数信息,动态地调整轮廓线和重建人体模型体表曲面,快速生成逼真的3D人体模型,从而满足服装CAD中根据用户身材尺寸大小定制服装的应用需求.  相似文献   

6.
三角网格模型上任意两点间的近似最短路径算法研究   总被引:13,自引:2,他引:13  
提出一种任意三角网格模型上两点间的近似最短路径算法.该算法首先将三角网格模型表示为带权图结构,然后用Dijkstra算法计算带权图中两顶点间的最短路径,并将其作为网格模型上该两点间最短路径的初始近似.通过不断地迭代对相关三角形边进行自适应细分,并构造每次细分后新的带权图,从而对网格模型上的两点间最短路径进行迭代逼近.该算法效率高,可以很好地控制精度,适用于大型三角网格模型两点间最短路径寻找.文中还讨论了该算法在任意三角网格模型区域划分中的应用.  相似文献   

7.
提出并实现了通过脚楦匹配方法来仿真人脚穿上鞋子的状态,能够直观、便利地检查和分析鞋类产品的舒适度。该方法包括三个步骤:首先,保持鞋楦的位置不动,调整脚型的位置,使其与鞋楦严格对齐;其次,基于轴线变形算法,对脚型进行略微变形,使其与鞋楦姿势匹配;最后,根据匹配结果生成脚楦多个截面的分析图,指导对鞋楦舒适度的分析和楦体修改。实验结果表明,该方法能够有效地检查鞋楦的舒适度,可应用到个性化定制业务。  相似文献   

8.
基于电子商务平台,提出了鞋产品的个性化定制系统。系统通过web形式获取客户对产品的形状要求,然后基于产品样式库,实现了鞋楦的参数化建模与精细调整,即根据客户输入的脚部参数构建满足这些参数要求的鞋楦模型。系统根据鞋楦模型生成其加工代码,完成鞋楦及鞋产品的生产,最后通过物流完成产品的配送。  相似文献   

9.
自适应三角网格模型重新布点算法的研究   总被引:5,自引:3,他引:5  
在对任意拓扑三角网格模型进行自动三边界区域划分的基础上,提出一种适应的三角网格模型重新布点算法,该算法首先根据三边界区域划分的结果,构造初始网格模型具有最低分辨率的基础网格模型,然后利用协调映射技术,对网格模型进行重新采样,从而不断对基础网格模型进行细化,算法的特点是可以根据不同的精度自动在曲面的大曲率处重新采样得到较多的点,而在曲面的小曲率处则重新采样得到较少的点,该算法可以用于三角网模型的自适应简化和优化,文中的应用实例表明,该算法可以保证在满足指定精度要求的条件下,得到更合理的三角网格模型,取得理想的效果。  相似文献   

10.
基于三角块的曲面纹理合成   总被引:4,自引:2,他引:4  
根据曲面网格上的切向矢量场,采用广度优先搜索策略从样本纹理空间中为每个三角面片映射纹理面片,直至完全覆盖整个网格.在搜索和映射过程中,首先使网格上相邻三角面片的纹理有最小的匹配误差;然后对相邻的三角面片纹理使用图的分割方法拼接纹理,得到曲面上连续的合成纹理;最后压缩存储合成的三角面片纹理.该算法适用于多种类型的样本纹理和任意的三角化曲面.  相似文献   

11.
With the rapid development of CAD/CAM technology and information technology, it is becoming possible to satisfy the quality, fit and comfort requirements of footwear design and manufacturing. In the footwear industry, although there are availability of design and manufacture technologies to fulfill the desired requirements, the current methods are very expensive. Cheap and accurate scanners are needed at the retail shop to acquire 3D foot shape information. This paper proposes a prediction method to model foot shapes through scaling a standard foot by using limited parameters. The accuracy of different number of parameters have been evaluated. Given that commercial expensive scanner accuracy range from 0.5 to 1 mm, in order to predict 3D foot shape to an accuracy of around 0.75 mm, foot outline, foot profile, two foot sections and standard foot model were required. The mean modeling errors were 0.76 mm and 0.75 mm of the right foot and left foot respectively. Results indicate that if more sections are used the modeling error decreases but this will increase the cost of the scanner and the computational complexity. This method provides a cost effective method to substitute expensive 3D foot scanners that usually use laser-based technology.Relevance to industry: This method provides the core algorithm for the development of low cost 3D foot scanners for footwear mass-customization. CCD cameras can be used to capture foot profile and outline, while fixed line laser can be used to obtain two key sections. This method reduces the need for expensive linear gears and optical systems.  相似文献   

12.
This paper describes a multiple camera-based method to reconstruct the 3D shape of a human foot. From a foot database, an initial 3D model of the foot represented by a cloud of points is built. The shape parameters, which can characterize more than 92% of a foot, are defined by using the principal component analysis method. Then, using "active shape models", the initial 3D model is adapted to the real foot captured in multiple images by applying some constraints (edge points' distance and color variance). We insist here on the experiment part where we demonstrate the efficiency of the proposed method on a plastic foot model, and also on real human feet with various shapes. We propose and compare different ways of texturing the foot which is needed for reconstruction. We present an experiment performed on the plastic foot model and on human feet and propose two different ways to improve the final 3D shapers accuracy according to the previous experiments' results. The first improvement proposed is the densification of the cloud of points used to represent the initial model and the foot database. The second improvement concerns the projected patterns used to texture the foot. We conclude by showing the obtained results for a human foot with the average computed shape error being only 1.06 mm.  相似文献   

13.
14.
《Ergonomics》2012,55(3):513-523
This study classifies the foot shapes of Taiwanese using 3D foot scanning data from 2000 males and 1000 females. Nine foot dimensions relative to foot length and absolute measures in the common foot length categories were applied to compare the gender differences. Using foot breadth in % foot length (% FL), ball of foot length in % FL and arch height in % FL as feature parameters, three foot shape types for males and females can be classified. Significant gender differences were found in seven of the nine foot dimensions. Females had greater ball of foot length than males (0.2% FL). When comparing feet of the same foot length, males had greater breadth, girth and height dimensions than females, except for toe height. In addition, ethnic differences in foot shape were also observed. The findings can provide very useful information for building gender-specific shoe lasts and designing footwear insoles.  相似文献   

15.
Contact modeling is an important aspect of simulation of many robotic tasks. In the paper, a compliant contact model with nonlinear damping is investigated, and many previously unknown characteristics of the model are developed. Compliance is used to eliminate many of the problems associated with using rigid body models with Coulomb friction, while the use of nonlinear damping eliminates the discontinuous impact forces and most sticky tensile forces which arise in Kelvin-Voigt linear models. Two of the most important characteristics of the model are the dependence of the coefficient of restitution on velocity and damping in a physically meaningful manner, and its computational simplicity. A full mathematical development for an impact response is given, along with the effects of the system and model parameters on energy loss. A quasistatic analysis gives results which are consistent with energy loss characteristics of a more complex distributed foundation model under sustained contact conditions. A foot contact example for a walking machine is given which demonstrates the applicability of the model for impact on foot placement, sustained contact during the support phase, and the breaking of the contact upon liftoff of the foot  相似文献   

16.
To customize last from multiple foot images, this paper presents a pragmatic approach. Not using any laser device, eight images are shot to construct a visual hull, and later the visual hull is refined by some surface features which are extracted from SIFT features. Then the digitized foot is cut into three parts and seven sections. These parts and sections are edited with interaction and finally deformed into a smooth and convex last which adhere to the digitized foot. The method has these novelties: (1) last is constructed from customizer’s foot images, which is fitting to the foot; (2) a unique imaging rack, which is beneficial to taking all-around images and estimating the preliminary model; (3) the digitized foot is cut into three parts and various constrains are applied so that the model is not firm but formable.  相似文献   

17.
Realistic modelling of a human-like character is one of the main topics in computer graphics to simulate human motion physically and also look realistically. Of the body parts, a human foot interacts with the ground, and plays an essential role in weight transmission, balancing posture and assisting ambulation. However, in the previous researches, the foot model was often simplified into one or two rigid bodies connected by a revolute joint. We propose a new foot model consisting of multiple segments to reproduce human foot shape and its functionality accurately. Based on the new model, we develop a foot pose controller that can reproduce foot postures that are generally not obtained in motion capture data. We demonstrate the validity of our foot model and the effectiveness of our foot controller with a variety of foot motions in a physics-based simulation.  相似文献   

18.
李新华  袁振宇  张涛 《计算机工程》2014,(2):246-249,255
针对人体足背的三维建模问题,提出一种基于线结构光扫描的新型重构及测量方案。采用2台高分辨率CMOS摄像头,从不同角度拍摄照射在足背上的线结构光线,通过灰度重心法细化图像中的结构光线,经坐标转换获得足背的点云数据。对足背点云数据后跟处的盲区采用最小二乘曲线拟合法进行修复,并运用三维Delaunay网格化算法实现曲面重构,获得完整的足背三维轮廓。实验结果表明,该方案程序运行稳定,足部主要参数的绝对误差均小于4mm,具有较高的测量精确度。  相似文献   

19.
Foot–ground contact models are an important part of forward dynamic biomechanic models, particularly those used to model gait, and have many challenges associated with them. Contact models can dramatically increase the complexity of the multibody system equations, especially if the contact surface is relatively large or conforming. Since foot–ground contact has a large potential contact area, creating a computationally efficient model is challenging. This is particularly problematic in predictive simulations, which may determine optimal performance by running a model simulation thousands of times. An ideal contact model must find a balance between accuracy for large, conforming surfaces, and computational efficiency.Volumetric contact modelling is explored as a computationally efficient model for foot–ground contact. Previous foot models have used volumetric contact before, but were limited to 2D motion and approximated the surfaces as spheres or 2D shapes. The model presented here improves on current work by using ellipsoid contact geometry and considering 3D motion and geometry. A gait experiment was used to parametrise and validate the model. The model ran over 100 times faster than real-time (in an inverse simulation at 128 fps) and matched experimental normal force and centre of pressure location with less than 7% root-mean-square error.In most gait studies, only the net reaction forces, centre of pressure, and body motions are recorded and used to identify parameters. In this study, contact pressure was also recorded and used as a part of the identification, which was found to increase parameter optimisation time from 10 to 164 s (due to the additional time needed to calculate the pressure distribution) but helped the results converge to a more realistic model. The model matched experimental pressures with 33–45% root-mean-square error, though some of this was due to measurement errors.The same parametrisation was done with friction included in the foot model. It was determined that the velocity-based friction model that was used was inappropriate for use in an inverse-dynamics simulation. Attempting to optimise the model to match experimental friction resulted in a poor match to the experimental friction forces, inaccurate values for the coefficient of friction, and a poorer match to the experimental normal force.  相似文献   

20.
Falls on the same level are a leading cause of non-fatal injuries in the construction industry, and loss of balance events are the primarily contributory risk factors associated with workers’ fall injuries. Previous studies have indicated that changes in biomechanical gait stability parameters provide substantial safety gait metrics for assessing workers’ fall risks. However, scant research has been conducted on changes in biomechanical gait stability parameters based on foot plantar pressure patterns to assess workers’ fall risks. This research examined the changes in spatial foot regions and loss of balance events associated with biomechanical gait stability parameters based on foot plantar pressure patterns measured by wearable insole pressure system. To test the hypotheses of this study, ten asymptomatic participants conducted laboratory simulated loss of balance events which are often initiated by extrinsic fall risk factors. Our results found: (1) statistically significant differences in biomechanical gait stability parameters between spatial foot regions, especially with the peak pressure parameter; and (2) statistically significant differences in biomechanical gait stability parameters between loss of balance events when compared to normal gait (baseline), especially with the pressure-time integral parameter. Overall, the findings of this study not only provide useful safety gait metrics for early detection of specific spatial foot regions but also allow safety managers to understand the mechanism of loss of balance events in order to implement proactive fall-prevention strategies.  相似文献   

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