虚拟人食指肌肉控制及运动约束研究

基于生理解剖结构,建立了虚拟人食指肌肉控制机制,通过控制多条肌肉收缩,实现了单指多关节灵活运动。同时针对传统模型单指运动控制较为独立,缺乏约束而导致不够真实的情况,研究了运动中双指间促进和制约的关系,提出了运动约束关系图。该图能够同时描述单指及双指的运动空间及其非线性约束关系,并刻画出实际不可到达区域。实验表明,所建立的控制机制能较好地仿真出食指的灵活运动,利用约束关系图能够保证手部仿真运动符合生理特征,具有较好的真实感和自然性。     

基于解剖学的人手肌肉建模技术

为实现仿真手在运动过程中符合人手的生理特性及运动特点,文中通过分析手的解剖结构,总结控制手部运动和形状的约束参数,采用层次建模方法,先建立用线段表示的含有约束参数的手部骨骼模型,然后在此基础上根据手部的特征横截面确定特征多边形,采用NURBS面片拟合的方法建立依附于骨骼之上的肌肉模型.此方法建立的手部模型在运动仿真过程中,手部肌肉以对应的骨骼为轴线并随着骨骼各个参数的变化而发生相应的变化,最终取得良好的仿真效果.     

基于解剖学的人手肌肉建模技术

为实现仿真手在运动过程中符合人手的生理特性及运动特点，文中通过分析手的解剖结构，总结控制手部运动和形状的约束参数．采用层次建模方法，先建立用线段表示的含有约束参数的手部骨骼模型，然后在此基础上根据手部的特征横截面确定特征多边形，采用NURBS面片拟合的方法建立依附于骨骼之上的肌肉模型。此方法建立的手部模型在运动仿真过程中，手部肌肉以对应的骨骼为轴线并随着骨骼各个参数的变化而发生相应的变化，最终取得良好的仿真效果。     

欠驱动多指节机器人手的仿真实现

欠驱动多指节机器人手具有较复杂的非线性运动方程组以及运动过程的阶段性,公用Ｓｉｍｕｌｉｎｋ仿真系统一般很难实现这种机器人手的动态仿真为此提出用Ｍａｔｌａｂ语言编写的Ｍ－文件与Ｓｉｍｕｌｉｎｋ的仿真系统之间的合理组合,实现多指节手的动态仿真过程。文中用于欠驱动多指节机器人手的动态仿真模型能够发映手指操作的起初过程,并能简化仿真系统的复杂性,这为多指节手的运动、受力分析以及机构、控制设计等提供了有效工     

新型欠驱动仿生灵巧手设计及实时操作控制

根据人手的生理结构,参考人手骨骼形状,设计了一种保留人手大部分生物力学特征的灵巧手控制模型。为满足灵巧手多指控制的同步性和数据传输的实时性,设计了数据传输模块以及舵机控制模块。针对欠驱动运动精度不高的特点,提出了类肌腱的仿生结构,使得各手指准确到达期望位置,减小腱驱动迟滞造成的不利影响。通过静力构型分析为类肌腱材料的选取提供依据,并通过运动学分析得到指尖一点的工作空间范围。最后通过多指灵巧抓取以及遥操作实验,验证所提控制系统的稳定性、可靠性。     

基于人眼多线谱的MPEG-4参数计算

提出了由人眼多线谱计算MPEG-4相关人脸动画参数(FAP)的方法.人眼多线谱利用一组随时间变化的归一化肌肉收缩量表示人眼运动及表情,通过对其采样可获得视频各帧对应的归一化肌肉收量.根据三雏肌肉控制人眼(3D-MCE)模型与MPEG-4标准模型在特征点、运动表示参数,坐标及尺度上的对应关系,可由归一化肌肉收缩量集计算相应FAP,以驱动任意基于MPEG-4标准的人眼模型.实验证明该方法所用数据量及计算量较小,所得MPEG-4参数可以驱动得到较逼真的人眼运动及表情.     

基于发音运动特征的舌部肌肉建模及仿真

人舌结构较为复杂,运动灵活,在虚拟人物发音及表情运动过程中起着关键的作用,但现有舌部模型结构较单一,实现的虚拟运动相对简单,描述能力不足,且需要大量数据驱动。针对以上问题,通过对舌部解剖结构的研究,提出一种基于肌肉运动特征的舌部模型及控制方法。将舌部内外肌群按其运动及发音功能进行分类,仅需获得多条肌肉不同的收缩量,即可利用各自的控制函数确定出参数值,进而实现模型前升高、后升高和谷形等多种常见运动。实验结果表明,该方法能够较为灵活便捷地控制虚拟舌体,仿真出符合生理特征的多种舌部运动。     

机器人多指手灵巧抓持规划

抓持规划是机器人灵巧手要完成预期任务所面临的一个重要问题．本文采用主从操作方式进行灵巧手的指尖抓持规划，由人手决定抓持接触点的位置， 灵巧手通过调整其手掌的位置和姿态保证各手指在人手指定的位置上抓持物体．根据灵巧手的操作特点，提出以关节灵活度来描述关节运动各向同性的能力，并据此定义灵巧手操作灵活度，作为灵巧手抓持位形性能的评价指标．以最大操作灵活度作为优化目标函数，寻求最优的抓持性能．同时，借鉴人手的抓持经验，通过主从操作方式，建立从人手到灵巧手的运动映射关系，从而为手掌位置优化问题提供合理的初值．仿真实验结果说明了文中方法的有效性．     

人手到灵巧手的运动映射实现

本文研究主从操作中人手到灵巧手的运动映射．提出了一种基于虚拟关节和虚拟手指的关节空间运动映射方法，实现了人手和灵巧手的三维运动仿真．以数据手套为人机接口，在虚拟环境下，通过直观地比较映射效果，验证了映射算法．     

基于Kinect的无标定人机交互控制系统设计

手部跟踪主从控制机械臂是一种新型的人机交互方式。利用Kinect传感器骨骼追踪技术处理景深数据获取手部位置,构建手部相对于髋骨中心与末端执行器相对于机械臂基座的运动映射关系,进行主从控制,实现人手与机器臂的实时交互。针对手部抖动消除和异常值处理,提出一种基于位置增量的移动平均轨迹平滑算法。实验结果表明,该系统能够很好完成手部跟踪和主从控制任务,具有较高的实时性和交互性。     

Analysing students' shared activity while modeling a biological process in a computer-supported educational environment

Abstract  This paper reports on a case study with three dyads of high school students (age 14 years) each collaborating on a plant growth modeling task in the computer-supported educational environment ' ModelsCreator '. Following a qualitative line of research, the present study aims at highlighting the ways in which the collaborating students as well as the facilitator who supported them are engaged in the computer-based modeling 'activity'. The analysis is carried out with a two-level analytic tool that has been derived within the theoretical framework of 'activity theory'. Our results show that a wide range of modeling 'operations' is activated in the context of the three major modeling 'actions' of 'analysis', 'synthesis' and 'testing-interpreting', which take place in the light of the facilitator-driven 'action' of cognitive and technical support. Moreover, these actions are combined into 'modeling units' of various forms which are repeated several times until the modeling process comes to an end. These many-fold repeats of the 'modeling unit' appear to shape a pattern which characterizes the computer-supported shared 'activity' as a whole.     

Context-aware garment modeling from sketches

Modeling of realistic garments is essential for creating believable virtual environments. Sketch-based modeling of garments presents an appealing, easy to use alternative to the established modeling approaches which are time consuming and require significant tailoring expertise. Unfortunately, the results created using existing sketch-based methods lack realism. Driven by human perception of garment sketches, we propose a context-aware garment sketch interpretation based on a set of observations about key factors that affect the shape of garments. Based on this analysis we develop a geometric method for sketch-based modeling of garments which obtains more realistic results than previous techniques. We demonstrate the effectiveness of our method on a variety of inputs and validate our approach via a user study where viewers were asked to compare the believability of our outputs versus previous ones.     

A ‘context-aware’ and agent-centric perspective for the alignment between individuals and organizations

The enterprise modeling field aims at representing organizations from several, inter-related perspectives. A number of enterprise modeling frameworks have been developed providing models, methods and tools that enable to communicate the structure and processes of organizations. These frameworks have been used both for systems development and organizational analysis ends, where the latter mainly focuses process (re)design efforts. We argue that enterprise modeling frameworks can be used for other kinds of organizational analysis. In particular, they can be used to capture and model work practices, human multitasking at work, and to compare models describing pre-defined behavior with actual execution.     

三维CAD 混合建模技术研究

三维数字化建模主要有两种技术：一是参数化建模,二是直接建模。但这 两种技术在实际应用中均存在缺陷。论文将两种建模方法融合在一起形成混合建模技术,能 更好地体现设计者的意图,提高设计效率。     

三维地质模型分析概述

由于三维地质建模需要对矿体的品位等属性信息进行详细的描述,所以三维地学建模须采用基于体元的方法建模,也可以由表面模型栅格化为体元模型。综述了现在常用的三维地质建模的一般方法,实体模型、四面体、块体模型、结构实体几何、似三棱柱等,并对各自的优缺点进行了分析,着重介绍了基于体元的建模方法,可为三维地质建模初学者提供一定的参考。     

A procedure for building product models

The application of product modeling in manufacturing companies raises the important question of how to model product knowledge in a comprehensible and efficient way. An important challenge is to qualify engineers to model and specify IT-systems (product models) to support their specification activities. A basic assumption is that engineers have to take the responsibility for building product models to be used in their domain. To do that they must be able to carry out the modeling task on their own without any need for support from computer science experts. This paper presents a set of simple, easily adaptable concepts and methods for modeling product knowledge. The concepts and methods are based on well-defined concepts and methods from data modeling (object oriented analysis) and domain modeling (product modeling). The concepts are general and can be used for modeling all types of specifications in the different phases in the product life cycle. The modeling techniques presented have been tested in different companies and have proved to work.     

MuscleBuilder: A modeling tool for human anatomy

A traditional multi-layered approach is adopted to human body modeling and deformation. The model is split into three general anatomical structures: the skeleton, musculature and skin. It is shown that each of these layers is modeled and deformed by using fast, procedural, ad-hoc methods that can painlessly be reimplemented. The modeling approach is generic enough to handle muscles of varying shape, size and characteristics and does not break in extreme skeleton poses. It is also described that the integrated MuscleBuilder system whose main features are: i) easy and quick creation of muscle deformation models; ii) automatic deformation of an overlying skin. It is shown that visually realistic results can be obtained at interactive frame rates with very little input from the designer.     

A Curvature and Density‐based Generative Representation of Shapes

This paper introduces a generative model for 3D surfaces based on a representation of shapes with mean curvature and metric, which are invariant under rigid transformation. Hence, compared with existing 3D machine learning frameworks, our model substantially reduces the influence of translation and rotation. In addition, the local structure of shapes will be more precisely captured, since the curvature is explicitly encoded in our model. Specifically, every surface is first conformally mapped to a canonical domain, such as a unit disk or a unit sphere. Then, it is represented by two functions: the mean curvature half‐density and the vertex density, over this canonical domain. Assuming that input shapes follow a certain distribution in a latent space, we use the variational autoencoder to learn the latent space representation. After the learning, we can generate variations of shapes by randomly sampling the distribution in the latent space. Surfaces with triangular meshes can be reconstructed from the generated data by applying isotropic remeshing and spin transformation, which is given by Dirac equation. We demonstrate the effectiveness of our model on datasets of man‐made and biological shapes and compare the results with other methods.     

Location-based services and GIS in perspective

This paper examines location-based services (LBS) from a broad perspective involving definitions, characteristics, and application prospects. We present an overview of LBS modeling regarding users, locations, contexts and data. The LBS modeling endeavors are cross-examined with a research agenda of geographic information science. Some core research themes are briefly speculated.     

SOA全生命周期建模方法综述

在介绍SOA(面向服务的架构)项目实施过程的基础上,从SOA全生命周期的视角,着重从方法论上对实施SOA项目所涉及到的业务流程建模、服务建模、数据建模、服务集成建模和业务监控建模进行了分析与评述,并提供了一些新的解决思路,同时指出了SOA建模领域的一些研究热点及趋势。