Hybrid client-server architecture and control techniques for collaborative product development using haptic interfaces

In this paper, a collaborative product development and prototyping framework is proposed by using distributed haptic interfaces along with deformable objects modeling. Collaborative Virtual Environment (CVE) is a promising technique for industrial product development and virtual prototyping. Network control problems such as network traffic and network delay in communication have greatly limited collaborative virtual environment applications. The problems become more difficult when high-update-rate haptic interfaces and computation intensive deformable objects modeling are integrated into CVEs for intuitive manipulation and enhanced realism. A hybrid network architecture is proposed to balance the computational burden of haptic rendering and deformable object simulation. Adaptive artificial time compensation is used to reduce the time discrepancy between the server and the client. Interpolation and extrapolation approaches are used to synchronize graphic and haptic data transmitted over the network. The proposed techniques can be used for collaborative product development, virtual assembly, remote product simulation and other collaborative virtual environments where both haptic interfaces and deformable object models are involved.     

A framework for collaborative top-down assembly design

This paper presents a new system framework for collaborative top-down assembly design. Different from current computer-aided design (CAD) systems, the framework allows a group of designers to collaboratively conduct product design in a top-down manner. In our framework, a multi-level and distributed assembly model is adopted to effectively support collaborative top-down assembly design. Meanwhile, fine-granularity collaborative design functionalities are provided. First, the coupled structural parameters involved in the distributed skeleton models of the product can be collaboratively determined by the correlative designers based on fuzzy and utility theory. Second, agent based design variation propagation is achieved to ensure the consistency of the multi-level and distributed assembly model during the whole design process. Third, collaborative design of assembly interfaces between the components assigned to different designers is supported. The prototype implementation shows that our framework works well for supporting practical collaborative top-down assembly design.     

Design and implementation of an agent-based collaborative product design system

The evolution of computer science and technology has brought new opportunities for multidisciplinary designers and engineers to collaborate with each other in a concurrent and coordinated manner. The development of computational agents with unified data structures and software protocols contributes to the establishment of a new way of working in collaborative design, which is increasingly becoming an international practice. In this paper, based on the analysis of the dynamic nature of collaborative design process, a new framework for collaborative design is described. This framework adopts an agent-based approach and relocates designers, managers, systems, and the supporting agents in a unified knowledge representation scheme for product design. In order to model the constantly evolving design process and the rationales resulted from design collaboration, a Collaborative Product Data Model (CPDM) and a constraint-based Collaborative Design Process Model (CDPM) are proposed to facilitate the management and coordination of the collaborative design process as well as design knowledge management. A prototype system of the proposed framework is implemented and its feasibility is evaluated using a real design scenario whose objective is designing a set of dining table and chairs.     

Collaborative virtual learning environments: design and evaluation

E-learning systems have gone through a radical change from the initial text-based environments to more stimulating multimedia systems. Such systems are Collaborative Virtual Environments, which could be used in order to support collaborative e-learning scenarios. The main aim of this paper is to aid educational designers in selecting, designing and evaluating three dimensional collaborative virtual environments in order to gain the pedagogical benefits of Computer Supported Collaborative Learning. Therefore, this paper initially discusses the potential of three dimensional networked virtual environments for supporting collaborative learning. Furthermore, based on a two-step platform selection process this paper (a) presents and compares three dimensional multi-user virtual environments for supporting collaborative learning and (b) validates the most promising solution against a set of design principles for educational virtual environments. According to these principles, an educational environment has been implemented on top of the selected platform in order to support collaborative e-learning scenarios. The design of this environment is also presented. In addition, this paper presents the results of three small scale studies carried out in a tertiary education department, to assess the educational environment. This environment has been evaluated based on a hybrid evaluation methodology for uncovering usability problems, collecting further requirements for additional functionality to support collaborative virtual learning environments, and determining the appropriateness of different kinds of learning scenarios.

A collaborative virtual geographic environment based on P2P and Grid technologies

Solving a geographic problem usually requires collaborative work among a group of people in different geographic locations. Collaborative virtual geographic environment (CVGE), an integrated technology, offers an intuitive, efficient, and interactive visualization environment through which geographically separated users can explore complicated spatial information and conduct collaborative work. In this paper, two new technologies, Peer-to-Peer (P2P) and Grid computing, are tightly coupled to develop a CVGE system. This paper evaluates the potential contributions of the P2P and Grid technology to CVGE systems. Using a Grid based system architecture efficiently integrates and shares geographically distributed resources as well as modeling procedures built on different platforms. To offer a shared and interactive virtual collaborative geographic environment for resolving geographic problems, we developed several P2P services including a terrain visualization collaboration service and a video collaboration service. Finally, a CVGE prototype system is implemented for collaboration on silt dam planning on the Loess plateau. The experimental results show that the scheme developed in this paper is efficient and feasible.     

Integration of fuzzy logic, genetic algorithms and neural networks in collaborative parametric design

The solution to a design problem is extracted through the exploitation of the design knowledge in the context of a space of solution alternatives. The design process incorporates a series of decision making and knowledge management issues, which should be often addressed through collaboration among diverse stakeholders. The alternative solutions must usually be shaped under different formalisms and evaluated against commonly accepted objective criteria.The current paper presents an approach that integrates soft-computing techniques in order to facilitate the computer-aided collaboration among designers. CopDeSC (Collaborative parametric Design with Soft-Computing) is the name of the system developed in order to implement this approach whose key features are: (a) the collaborative structuring of design parameter hierarchies, (b) the modeling of the design objectives through fuzzy preferences stated by the designers on certain design parameters, (c) the deployment of genetic algorithms for locating the optimum solution and (d) the utilization of records of elite solutions that are submitted in a neuro-fuzzy approximation in order to produce a simplified problem formulation, suitable for addressing redesign tasks in significantly less computational time.The efficiency of CopDeSC is evaluated in an example case of the parametric design of oscillating conveyor that has been conducted by a group of designers.     

协同开发环境中的CAD/CAM集成数据管理的实现

协同开发环境是虚拟企业高效运作的支撑平台,CAD/CAM集成系统是该环境中的重要子系统,迫切需要对CAD/CAM集成数据进行有效的管理和操作。文章讨论了协同开发环境中CAD/CAM集成数据的管理技术,并详细分析了CAD/CAM集成数据库的数据结构和数据集成。     

A collaborative approach to assembly sequence planning

Distributed product development requires collaborative work among team members. For the sake of supporting assembly planning activities involving geographically dispersed designers, this paper presents an approach of collaborative assembly sequence planning to validate the assemblability of parts and subassemblies rapidly. In order to increase the planning efficiency and support the collaborative planning, role-based model is exploited to compress or simplify the product. In role-based model, the B-rep models are simplified according to the permissions associated with the role, so the surfaces invisible from outside of the model are removed. In collaborative planning, the planning tasks are assigned to different designers that carry out the collaborative planning, respectively. In this paper, a knowledge-based approach is proposed to the assembly sequence planning problem. This research shows that the typical or standard CSBAT (Connection Semantics Based Assembly Tree) can be applied to a given assembly problem. This paper presents the structure of the Co-ASP (Collaborative Assembly Sequence Planning System) and provides an example to illustrate the collaborative planning approach.     

A constraint-based system for product design and manufacturing

Constraint-based modeling is one of the most modern methods of product design. This paper illustrates a collaborative design and manufacture procedures based on a new approach under the constraint-based solver for product design. Such a method can be used for the collaborative computer-aided design/manufacture systems. A developing model will be constructed from conceptual design to tool-paths generation, and a case study of how to make a playing doll house was presented to verify this system.     

Advances in collaborative CAD: the-state-of-the art

In collaborative design and distributed manufacturing, the need to co-develop parts by designers at different geographical locations often arises. For designing a promising product, there is always a need for collaboration among the design, marketing, finance and procurement departments, and the top management. Global manufacturing makes it difficult to frequently gather all the departments in a meeting room to discuss, because of geographical constraints. In order to address this issue, recently, a number of software tools and research works have arisen to provide collaborative solutions. In this paper, some important works in Web-based visualization and 3D concise representations, 3D streaming technology and co-design systems and feature-/assembly-based representation are elaborated. Meanwhile, previous works done by a project led by the authors towards this direction are also highlighted.     

基于语义特征造型的虚拟装配

协同虚拟装配技术是虚拟样机技术与虚拟现实技术相结合所产生的一个新的研究热点。基于细胞元表示的语义特征造型技术,提出一种统一的协同虚拟装配框架,在该框架下能够有效支持异构CAD系统间零件及装配体的协同装配。网络传输以特征依赖图存储的操作信息,可降低网络负荷,提高响应速度。该思想初步应用在自主开发的HUST-CAIDS与UG间的异构协同设计中,证明了以上理论的可行性。     

Design formalism for collaborative assembly design

Joints in product design are common because of the limitations of component geometric configurations and material properties, and the requirements of inspection, accessibility, repair, and portability. Collaborative product design is emerging as a viable alternative to the traditional design process. The collaborative assembly design (AsD) methodologies are needed for distributed product development. Existing AsD methodologies have limitations in capturing the non-geometric aspects of designer's intent on joining and are not efficient for a collaborative design environment. This paper introduces an AsD formalism and associated AsD tools to capture joining relations and spatial relationship implications. This AsD formalism allows the joining relations to be modeled symbolically for computer interpretation, and the model can be used for inferring mathematical and physical implications. An AsD model generated from the AsD formalism is used to exchange AsD information transparently in a collaborative AsD environment. An assembly relation model and a generic assembly relationship diagram are to capture assembly and joining information concisely and persistently. As a demonstration, the developed AsD formalism and AsD tools are applied on a connector assembly with arc weld and rivet joints.     

协同CAD中基于角色视图技术的存取控制*

提出了协同CAD中信息存取的机制,这种机制是以基于角色的视图技术为基础的。通过对3D模型的几何分割,使基于角色的访问控制成为可能。提取一个被适当简化的、对协同设计单个设计者的存取权限适宜的模型,这种提取由复杂的存取机制所驱使。     

Internet驱动的产品协同装配理论和技术研究*

介绍了Internet驱动的分布式产品协同装配中的关键技术问题,协同装配设计平台的构建、产品模型呈现方法、冲突处理、协同装配信息建模和协同装配设计优化,并分析总结了目前存在的问题。最后构建了一个全面的产品协同装配系统框架。     

工作流管理系统中协同建模环境的研究

工作流建模是工作流技术能否在企业中成功应用的一项关键技术。传统工作流管理系统中的建模工具只支持单用户建模，不利于对持续变化、不可预测的市场需求做出迅速而准确的反应。提出了一个工作流管理系统中协同建模环境的概念框架，并对该框架中的相关内容：协同建模语言、访问控制、建模相关信息的感知以及模型定义冲突的管理作了讨论，最后展望了下一步的研究内容。     

A time-based approach to effective recommender systems using implicit feedback

Recommender systems provide personalized recommendations on products or services to customers. Collaborative filtering is a widely used method of providing recommendations using explicit ratings on items from users. In some e-commerce environments, however, it is difficult to collect explicit feedback data; only implicit feedback is available.

In this paper, we present a method of building an effective collaborative filtering-based recommender system for an e-commerce environment without explicit feedback data. Our method constructs pseudo rating data from the implicit feedback data. When building the pseudo rating matrix, we incorporate temporal information such as the user’s purchase time and the item’s launch time in order to increase recommendation accuracy.

Based on this method, we built both user-based and item-based collaborative filtering-based recommender systems for character images (wallpaper) in a mobile e-commerce environment and conducted a variety of experiments. Empirical results show our time-incorporated recommender system is significantly more accurate than a pure collaborative filtering system.     

协同语义特征建模技术研究

为了提高协同语义建模系统的性能,提出了一种新的协同设计方法,亦即使用特征语义表示法和细胞元模型来表示数据和管理模型中的各种数据和信息,然后通过语义匹配的方法来确定子模型间的逻辑和装配关系,通过语义区域划分、"最值空间"等技术来检测和消解协同设计中发生的操作冲突,最后通过创建临时模型来降低全局约束求解的复杂度。这种方法不仅能够完全实现协同语义特征建模的需要,还可以大大提高协同设计的效率。实验表明,该算法具有更强的适应性和实用性。     

The design and realization of CoViD: a system for collaborative virtual 3D design

Many important decisions in the design process are made during fairly early on, after designers have presented initial concepts. In many domains, these concepts are already realized as 3D digital models. Then, in a meeting, the stakeholders for the project get together and evaluate these potential solutions. Frequently, the participants in this meeting want to interactively modify the proposed 3D designs to explore the design space better. Today’s systems and tools do not support this, as computer systems typically support only a single user and computer-aided design tools require significant training. This paper presents the design of a new system to facilitate a collaborative 3D design process. First, we discuss a set of guidelines which have been introduced by others and that are relevant to collaborative 3D design systems. Then, we introduce the new system, which consists of two main parts. The first part is an easy-to-use conceptual 3D design tool that can be used productively even by naive users. The tool provides novel interaction techniques that support important properties of conceptual design. The user interface is non-obtrusive, easy-to-learn, and supports rapid creation and modification of 3D models. The second part is a novel infrastructure for collaborative work, which offers an interactive table and several large interactive displays in a semi-immersive setup. It is designed to support multiple users working together. This infrastructure also includes novel pointing devices that work both as a stylus and a remote pointing device. The combination of the (modified) design tool with the collaborative infrastructure forms a new platform for collaborative virtual 3D design. Then, we present an evaluation of the system against the guidelines for collaborative 3D design. Finally, we present results of a preliminary user study, which asked naive users to collaborate in a 3D design task on the new system.     

Multi-User Collaborative Assembly Planning over the Internet

1 Introduction Assembly planning is an important issue of product design for assembly, and many achievements have been obtained. Techniques such as geometric reasoning [1,2], genetic algorithms (GA) [3], virtual assembly [4,5] and so on are employed to assembly planning of relatively simple products successfully. But for the more complex cases, there is a combinational complexity problem when the geometric reasoning method is used. The fitness function in GA cannot take into account various…     

Multi-User Collaborative Assembly Planning over the Internet

Due to the increasing complexity of products and for the distributed product development, more closely collaborative work among designers is required. A collaborative assembly planning approach is proposed to support assembly planning in a networked environment. The working procedure is depicted and the key techniques including collaborative-planning-oriented assembly decomposition modeling, assembly assignment modeling, and sub-plans merging are addressed. By incorporating visual models at client side with assembly application models at server side, a web-based supporting environment for collaborative assembly planning has been developed using VRML and Java-EAI techniques. A case study is given to illustrate the feasibility and validity of the idea.