A versatile virtual prototyping system for rapid product development

This paper presents a versatile virtual prototyping (VP) system for digital fabrication of multi-material prototypes to facilitate rapid product development. The VP system comprises a suite of software packages for multi-material layered manufacturing (MMLM) processes, including multi-toolpath planning, build-time estimation and accuracy analysis, integrated with semi-immersive desktop-based and full-immersive CAVE-based virtual reality (VR) technology. Such versatility makes the VP system adaptable to suit specific cost and functionality requirements of various applications.

The desktop-based VR system creates a semi-immersive environment for stereoscopic visualisation and quality analysis of a product design. It is relatively cost-effective and easy to operate, but its users may be distracted by environmental disturbances that could possibly diminish their efficiency of product design evaluation and improvement. To alleviate disturbance problems, the CAVE-based VR system provides an enclosed room-like environment that blocks out most disturbances, making it possible for a design team to fully concentrate and collaborate on their product design work.

The VP system enhances collaboration and communication of a design team working on product development. It provides simulation techniques to analyse and improve the design of a product and its fabrication processes. Through simulations, assessment and modification of a product design can be iterated without much worry about the manufacturing and material costs of prototypes. Hence, key factors such as product shape, manufacturability, and durability that affect the profitability of manufactured products are optimised quickly. Moreover, the resulting product design can be sent via the Internet to customers for comments or marketing purposes. The VP system therefore facilitates advanced product design and helps reduce development time and cost considerably.     

An integrated manufacturing system for rapid tooling based on rapid prototyping

To reduce the time and cost of moulds fabrication, a novel integrated developing and manufacturing system of rapid tooling (RT) based on rapid prototyping (RP) is proposed. The architecture of system which consists of four building blocks: digital prototype, virtual prototype (VP), physical prototype and RT system, is presented. A digital prototype can be established by 3D CAD software packages or reveres engineering technique. A VP is employed to guide in optimization of the mould design and manufacturing process planning. A physical prototype, which is built using RP technology, generally serves as a pattern for producing RT. By integrating these building blocks closely, the system can aid effectively in mould design, analysis, prototyping, simulating, and manufacturing process development. Three typical cases are discussed in detail to illustrate the application of the system. It has been shown from a number of case studies that the system has a high potential to reduce further the cycle and cost of die development while minimizing error introduction. As a result, the integrated system provides a feasible and useful tool for companies to speed up their product development.     

A virtual prototyping approach to product disassembly reasoning

An important aspect of Design for the Life Cycle is assessing the disassemblability of products. After an artifact has completed its useful life, it must be disassembled then recycled, remanufactured or scrapped. Disassemblability of a product can be evaluated by performing disassembly activities on prototypes. Virtual prototyping (VP) is an alternative to hardware prototyping in which analysis of designs can be done without manufacturing physical samples. In recent years, disassembly processes have been generated either by using interactive or automated approaches, but these approaches have limitations. Interactive approaches require extensive user input usually in the form of answering questions, whereas automated approaches can only be used to generate disassembly processes for products with simple component configuration and geometry. In this paper automated and interactive techniques are combined, using VP, to generate complete disassembly processes of a product design. To support generation of disassembly processes of a product, a virtual environment and VP method were developed that will support disassembly activities performed by a designer. The product model of the virtual prototype is generated from the CAD model. The disassembly process model for the prototype is generated using automated reasoning techniques and is completed by interactively disassembling the product in the virtual environment. Extensions to automatic reasoning techniques to compute ranges of feasible directions of component removal were developed to facilitate the generation of the disassembly process. A scheme to represent the disassembly process for disassemblability evaluation was developed and implemented. In this paper a Chrysler LHS center console has been used to illustrate our approach of generating disassembly processes via VP.     

Error-based segmentation of cloud data for direct rapid prototyping

This paper proposes an error-based segmentation approach for direct rapid prototyping (RP) of random cloud data. The objective is to fully integrate reverse engineering and RP for rapid product development. By constructing an intermediate point-based curve model (IPCM), a layer-based RP model is directly generated from the cloud data and served as the input to the RP machine for fabrication. In this process, neither a surface model nor an STL file is generated. This is accomplished via three steps. First, the cloud data is adaptively subdivided into a set of regions according to a given subdivision error, and the data in each region is compressed by keeping the feature points (FPs) within the user-defined shape tolerance using a digital image based reduction method. Second, based on the FPs of each region, an IPCM is constructed, and RP layer contours are then directly extracted from the models. Finally, the RP layer contours are faired with a discrete curvature based fairing method and subsequently closed to generate the final layer-based RP model. This RP model can be directly submitted to the RP machine for prototype manufacturing. Two case studies are presented to illustrate the efficacy of the approach.     

快速原型虚拟逼真设计原理及体系结构

在分析设计的特点和发展趋势的基础上,提出快速原型虚拟逼真设计,并对其特点和原理进行了讨论,快速原型虚拟逼真设计是面向并行工具,基于虚拟原型和虚拟环境仿真的设计,强调虚拟原型的快速生成和演化,在关键技术,原型系统以及开发环境三个层次上论述了快速原型虚拟逼真设计的研究,提出快速原型虚拟逼真设计模型以及基于该模型的体系结构。     

Rapid prototyping: Applications in academic institutions and industry

In today's competitive world, the manufacturers have to get a new and improved product to the market as fast as possible to be able to compete in the global market. The major obstacle for this task had been a long product development cycle, i.e., design, prototype manufacture and testing. The introduction of rapid prototyping (RP) in the early stages of product development has greatly reduced the development time frame and cost involved in prototype manufacturing. Furthermore, RP applications are growing very fast in such a way that it is now possible to produce parts not as prototypes, but as final parts to be used in several engineering applications. Thus, RP is now acting as a bridge to help designers, manufacturing engineers, marketing and sales personnel to provide goods timely to the customer. This paper discusses practices, current developments and future trends of RP. This paper also discusses the use and role of RP in academic institutions.     

ProNoC: A low latency network-on-chip based many-core system-on-chip prototyping platform

Network-on-chip (NoC) is an emerging interconnect infrastructure to address the scalability limitation of conventional shared bus architecture for many-core system-on-chip (MCSoC). Current field-programmable gate arrays (FPGAs) have over million lookup tables, making it possible to prototype a complete NoC-based MCSoC on a single FPGA device. FPGA prototyping allows rapid system verification and optimum design parameters estimation. However, existing NoC-based MCSoC prototypes are usually adopting simple NoC architectural functionality. These NoC prototypes cannot represent a realistic projection of the state-of-the-art application-specific integrated circuit (ASIC) NoCs as these prototypes have limited overall system performance. This paper presents ProNoC, an integrated tool for rapid prototyping and validation of NoC-based MCSoC projects targeting FPGA devices. ProNoC adopts most advanced NoC features such as the support of virtual channel (VC), virtual network, low latency routing and different routing algorithms. Results show that NoC interconnect in ProNoC outperforms CONNECT, the most recent VC based prototype NoC with lower logic cell utilization, higher maximum operating frequency, higher average saturation throughput, and lower average communication latency. Moreover, ProNoC is equipped with graphical user interface to facilitate the development of MCSoC prototypes on FPGA platforms.     

复杂产品虚拟样机技术研究

虚拟样机技术尤其是面向多领域支持复杂系统的协同虚拟样机仿真支撑平台的研究已成为研发的热点。通过对Agent技术和WEB服务技术以及虚拟样机仿真系统的长期研究,提出了一种面向多领域的复杂产品虚拟样机仿真支撑平台的实现方案,给出了该仿真支撑平台的基于Agent和WEB服务的系统结构和虚拟样机设计中涉及的机械,电子,控制,软件等领域的智能Agent的统一描述,讨论了虚拟样机仿真支撑系统中Agent间的通信方式并阐明了系统的工作流程和信息集成模式,为虚拟样机的进一步发展和应用奠定了基础。     

Prototyping and analysing ubiquitous computing environments using multiple layers

If ubiquitous computing (ubicomp) is to enhance physical environments then early and accurate assessment of alternative solutions will be necessary to avoid costly deployment of systems that fail to meet requirements. This paper presents APEX, a prototyping framework that combines a 3D Application Server with a behaviour modeling tool. The contribution of this framework is that it allows exhaustive analysis of the behaviour models that drive the prototype while at the same time enabling immersive exploration of a virtual environment simulating the proposed system. The development of prototypes is supported through three layers: a simulation layer (using OpenSimulator); a modelling layer (using CPN Tools) and a physical layer (using external devices and real users). APEX allows movement between these layers to analyse different features, from user experience to user behaviour. The multi layer approach makes it possible to express user behaviour in the modelling layer, provides a way to reduce the number of real users needed by adding simulated avatars, and supports user testing of hybrids of virtual and real components as well as exhaustive analysis. This paper demonstrates the approach by means of an example, placing particular emphasis on the simulation of virtual environments, low cost prototyping and the formal analysis capabilities.     

A cooperative virtual prototyping system for mechatronic solution elements based assembly

In order to catch up with the steps of rapidly changing markets, the product development period of modern mechatronic products has to be as short as possible. However, mechatronic engineering is based on the interaction of mechanical engineering, electronic engineering, and computer science. Therefore, inefficient communication between the engineers who come from different domains becomes a manifest obstruction for accelerating the design of mechatronic products. Nevertheless, innovations in the field of virtual prototyping offer some potential solutions to this problem. In this paper, we present a cooperative virtual prototyping system, which utilizes the concept of solution elements and virtual reality techniques to facilitate assembling and analyzing virtual mechatronic prototypes in a multi-disciplinary workgroup.     

Knowledge-Based Integration Between Virtual and Physical Prototyping for Identifying Behavioral Constraints of Embedded Real-Time Systems

Rapid prototyping methods are in need of autonomous decision making and analysis during the product development stages so that the ldquotime-to-marketrdquo can be reduced faster than traditional product development methodologies. Therefore, new methods of prototyping are inevitably essential. This paper proposes an approach to utilize the benefits of virtual prototyping (VP) and physical prototyping (PP) methodologies by integrating them into knowledge-based systems (KBSs) by providing seamless connection. This approach is termed autonomous integrated prototyping. The main contribution of this paper is the development of an intelligent system architecture to facilitate and guide the product development autonomously and simultaneously in both VP and PP environments. The seamless connection between VP and PP, along with KBSs, enables the exploration of new behaviors of developing systems and analyzing different behaviors. The architecture is applicable to embedded real-time systems (ERTSs), sensor applications, robotics, and ubiquitous applications where system interaction with the external environment is necessary.     

Practical prototyping

The design of robotic mechanisms is a complex process involving geometric, kinematic, dynamic, tolerance, and stress analyses. In the design of a real system, the construction of a physical prototype is often considered. Indeed, a physical prototype helps the designer to identify the fundamental characteristics and the potential pitfalls of the proposed architecture. However, the design and fabrication of a prototype using traditional techniques is rather long, tedious, and costly. In this context, the availability of rapid prototyping machines can be exploited in order to allow designers of robotic mechanisms to build prototypes rapidly and at a low cost. In the article, the rapid prototyping of mechanisms using a commercially available computer-aided design (CAD) package and a fused deposition modeling (FDM) rapid prototyping machine is presented. A database of lower kinematic pairs (joints) is developed using the CAD package, and parameters of fabrication are determined experimentally for each of the joints. These joints are then used in the design of the prototypes where the links are developed and adapted to the particular geometries of the mechanisms to be built. Also, a procedure is developed to build gears and Geneva mechanisms. Examples of mechanisms are then studied and their design is presented. For each mechanism, the joints are described and the design of the links is discussed. Some of the physical prototypes built using the FDM rapid prototyping machine are shown     

Virtual prototyping of automated manufacturing systems with Geometry-driven Petri nets

The design process of automated manufacturing systems typically involves physical prototypes to validate the interactions between hardware and software components. However, physical prototyping is expensive and time consuming, which often leads to insufficient opportunities for testing early during the development cycle. Our objective is to improve this situation by providing a method to develop realistic prototypes using virtual reality technology that can be applied during earlier development stages. Our approach combines a virtual reality engine capable of enacting the laws of rigid body physics with a new hybrid software modelling language to control the simulated hardware using virtual sensors and actuators as they would be present in a physical prototype. The new modelling language is called Geometry-driven Petri nets (GPN) and combines a class of timed, high-level Petri nets with data structures used in state-of-the-art VR environments. This article describes the new GPN approach, applies it to a case study of an automated manufacturing line, and compares it with related approaches.     

A multi-material virtual prototyping system

This paper proposes a multi-material virtual prototyping system for digital fabrication of heterogeneous prototypes. It consists mainly of a topological hierarchy-sorting algorithm for processing slice contours, and a virtual simulation system for visualisation and optimisation of multi-material layered manufacturing (MMLM) processes. The topological hierarchy-sorting algorithm processes the hierarchy relationship of complex slice contours. It builds a parent-and-child list that defines the containment relationship of the slice contours, and subsequently arranges the contours in an appropriate sequence, which facilitates toolpath planning for MMLM by avoiding redundant tool movements. The virtual simulation system simulates MMLM processes and provides stereoscopic visualisation of the resulting multi-material prototypes for quality analysis and optimisation of the processes.     

虚拟样机技术及其在轻武器研制中的应用

给出了虚拟样机技术一个建议性的定义并论述了虚拟样机、虚拟现实及虚拟制造之间的区别.在新型单兵自卫武器的研制中引入虚拟样机技术.仿真评估结果表明：所建立的虚拟样机具有模拟物理样机的能力.这种虚拟样机应用的新方法在轻武器的研制中具有十分重要的意义.     

虚拟样机三维表现系统设计与实现

虚拟样机是一种新型的基于一体化产品和过程开发策略的新的设计、开发手段。本文首先介绍了协同虚拟样机的基本概念和样机设计过程中对可视化的要求,接着对虚拟样机三维表现系统进行设计,最后对支持虚拟样机分布表现的虚拟样机软总线技术和同步技术进行分析。     

面向并行设计的虚拟原型技术研究

虚拟原型技术是在虚拟的逼真环境下,对产品设计信息进行协同仿真验证的有效手段,它可有效支持并行设计,缩短产品开发周期,在分析了虚拟原型与并行的关系后,提出了基于域对象的虚拟原型建模与仿真方法,并阐述了支持虚拟原型的集成框架的关键技术。     

Modelling cloud data using an adaptive slicing approach

In reverse engineering, the conventional surface modelling from point cloud data is time-consuming and requires expert modelling skills. One of the innovative modelling methods is to directly slice the point cloud along a direction and generate a layer-based model, which can be used directly for fabrication using rapid prototyping (RP) techniques. However, the main challenge is that the thickness of each layer must be carefully controlled so that each layer will yield the same shape error, which is within the given tolerance bound. In this paper, an adaptive slicing method for modelling point cloud data is presented. It seeks to generate a direct RP model with minimum number of layers based on a given shape error. The method employs an iterative approach to find the maximum allowable thickness for each layer. Issues including multiple loop segmentation in layers, profile curve generation, and data filtering, are discussed. The efficacy of the algorithm is demonstrated by case studies.     

基于虚拟样机的复杂产品协同设计与仿真关键技术研究

主要研究并行工程环境下复杂产品虚拟样机协同设计与仿真的体系结构及其关键技术。提出虚拟样机协同设计与仿真系统的体系结构与整体解决方案,研究面向虚拟样机的数字化多领域集成建模理论与方法,建立面向虚拟样机开发全生命周期的集成过程管理与冲突协调模型,提出面向复杂产品虚拟样机开发的多学科协同设计、协同仿真和智能决策支持的理论与方法,建立复杂产品虚拟样机协同支持环境,有效提高企业创新能力和核心竞争力。