A Photo-Modeling Approach to Restituting 3D Model Data from Single 2D Imagery for Rapid Prototyping of Artifact Products

This article first generalizes the basic engineering phases of modern rapid prototyping processes, and then describes the techniques of data capture for data modeling and model making. The article also provides a brief overview of the photogrametric techniques of restitution of 3D objects, and highlights the difficulties and limitations of existing methods. It therefore presents a novel approach to photo-modeling for acquiring 3D model data from single 2D photorealistic images. Implementation of the approach is then described against a background of rapid prototyping processes to demonstrate the effectiveness of photo-modeling practice.     

State-chain sequential feedback reinforcement learning for path planning of autonomous mobile robots

This paper deals with a new approach based on Q-learning for solving the problem of mobile robot path planning in complex unknown static environments.As a computational approach to learning through interaction with the environment,reinforcement learning algorithms have been widely used for intelligent robot control,especially in the field of autonomous mobile robots.However,the learning process is slow and cumbersome.For practical applications,rapid rates of convergence are required.Aiming at the problem of slow convergence and long learning time for Q-learning based mobile robot path planning,a state-chain sequential feedback Q-learning algorithm is proposed for quickly searching for the optimal path of mobile robots in complex unknown static environments.The state chain is built during the searching process.After one action is chosen and the reward is received,the Q-values of the state-action pairs on the previously built state chain are sequentially updated with one-step Q-learning.With the increasing number of Q-values updated after one action,the number of actual steps for convergence decreases and thus,the learning time decreases,where a step is a state transition.Extensive simulations validate the efficiency of the newly proposed approach for mobile robot path planning in complex environments.The results show that the new approach has a high convergence speed and that the robot can find the collision-free optimal path in complex unknown static environments with much shorter time,compared with the one-step Q-learning algorithm and the Q(λ)-learning algorithm.     

Dynamic organization and methodology for agile virtual enterprises

With the trend of the worldwide market competition ,the global agile manufacturing will become an advanced manufacturing technology in 21st century,and the Agile Virtual Enterprise(AVE) will also become a new organization form of manufacturing enterprises.As AVE is a complicated enterprise,how to build an optimal AVE organuization is a difficult problem.In this paper,based on the analysis of the AVE organization,the methodology for AVE including enterprise architecture,reference model,enterprise modeling methods and toolkit,guideline for system implementation is proposed.This paper also presents a Virtual Organization Integrated Support Environment(VOISE),which provides the computer-aided support for rapidly duilding an optimal AVE.     

STEP-NC based high-level machining simulations integrated with CAD/CAPP/CAM

With the development of manufacturing,numerical control(NC) machining simulation has become a modern tool to obtain safe and reliable machining operations.Although some research and commercial software about NC machining simulations is available,most of them is oriented for G&M code.It is a low-level data model for computer numerical control(CNC),which has inherent drawbacks such as incomplete data and lack of accuracy.These limitations hinder the development of a real simulation system.Whereas,standard for the exchange of product data-compliant numerical control(STEP-NC) is a new and high-level data model for CNC.It provides rich information for CNC machine tools,which creates the condition for an informative and real simulation.Therefore,this paper proposes STEP-NC based high-level NC machining simulations solution integrated with computer-aided design/computeraided process planning/computer-aided manufacturing(CAD/CAPP/CAM).It turned out that the research provides a better informed simulation environment and promotes the development of modern manufacturing.     

Research on Application of Visual Simulation System of Expressway

1 Introduction With the interlaced development of computer science and civil engineering, visual simulation has become a comprehensive technology that uses virtual model to research and analyze the real or assumed system based on mathematics theories, modeling techniques and information technology. Recently, it has been applied success fully in expressway construction. With this technology, the abstract data can be dealt with the visualization process to generate 3D models and realize visual e…     

Multi-volume CAD modeling for heterogeneous object design and fabrication

The current computer-aided technologies in disign and product development,the evolution of CAD modeling,and a framework of multi-volume CAD modeling system for heterogeneous object design and fabrication are presented in this paper.The multi-volume CAD modeling system is presented based on nonmanifold topological elements.Material identifications are defined as design attributes introduced along with geometric and topological information at the design stage.Extended Euler operation and reasoning Boolean operations for merging and extraction are executed according to the associated material identifications in the developed multi-volume modeling system for heterogeneous object.An application example and a pseudo-processing algorithm for prototyping of heterogeneous structure through solid free-form fabrication are also described.     

Influence of Data Clouds Fusion From 3D Real-Time Vision System on Robotic Group Dead Reckoning in Unknown Terrain

This paper proposes the solution of tasks set required for autonomous robotic group behavior optimization during the mission on a distributed area in a cluttered hazardous terrain.The navigation scheme uses the benefits of the original real-time technical vision system(TVS)based on a dynamic triangulation principle.The method uses TVS output data with fuzzy logic rules processing for resolution stabilization.Based on previous researches,the dynamic communication network model is modified to implement the propagation of information with a feedback method for more stable data exchange inside the robotic group.According to the comparative analysis of approximation methods,in this paper authors are proposing to use two-steps post-processing path planning aiming to get a smooth and energy-saving trajectory.The article provides a wide range of studies and computational experiment results for different scenarios for evaluation of common cloud point influence on robotic motion planning.     

Energy Consumption Prediction of a CNC Machining Process With Incomplete Data

Energy consumption prediction of a CNC machining process is important for energy efficiency optimization strategies.To improve the generalization abilities,more and more parameters are acquired for energy prediction modeling.While the data collected from workshops may be incomplete because of misoperation,unstable network connections,and frequent transfers,etc.This work proposes a framework for energy modeling based on incomplete data to address this issue.First,some necessary preliminary operations are used for incomplete data sets.Then,missing values are estimated to generate a new complete data set based on generative adversarial imputation nets(GAIN).Next,the gene expression programming(GEP)algorithm is utilized to train the energy model based on the generated data sets.Finally,we test the predictive accuracy of the obtained model.Computational experiments are designed to investigate the performance of the proposed framework with different rates of missing data.Experimental results demonstrate that even when the missing data rate increases to 30%,the proposed framework can still make efficient predictions,with the corresponding RMSE and MAE 0.903 k J and 0.739 k J,respectively.     

Direct Rapid Prototyping of Metal Parts by Hybrid of Plasma Deposition and Milling Machine

1 Introduction Layered manufacturing is the key technology of rapid prototyping (RP) technology, and it allows to fabricate three-dimensional parts layer-by-layer[1]. Material is added layer-by-layer in contrast to removing material in machining processes[2]. However, most of the commercially available materials such as photo-polymers, powders, paper, wax, plastic materials, and even rubber, are only suitable for making concept models, visual prototypes, and some limited functional prototypes…     

SVM based layout retargeting for fast and regularized inverse lithography

Inverse lithography technology （ILT）, also known as pixel-based optical proximity correction （PB-OPC）, has shown promising capability in pushing the current 193 nm lithography to its limit. By treating the mask optimization process as an inverse problem in lithography, ILT provides a more complete exploration of the solution space and better pattern fidelity than the tradi-tional edge-based OPC. However, the existing methods of ILT are extremely time-consuming due to the slow convergence of the optimization process. To address this issue, in this paper we propose a support vector machine （SVM） based layout retargeting method for ILT, which is designed to generate a good initial input mask for the optimization process and promote the convergence speed. Supervised by optimized masks of training layouts generated by conventional ILT, SVM models are learned and used to predict the initial pixel values in the‘undefined areas’ of the new layout. By this process, an initial input mask close to the final optimized mask of the new layout is generated, which reduces iterations needed in the following optimization process. Manu-facturability is another critical issue in ILT;however, the mask generated by our layout retargeting method is quite irregular due to the prediction inaccuracy of the SVM models. To compensate for this drawback, a spatial filter is employed to regularize the retargeted mask for complexity reduction. We implemented our layout retargeting method with a regularized level-set based ILT （LSB-ILT） algorithm under partially coherent illumination conditions. Experimental results show that with an initial input mask generated by our layout retargeting method, the number of iterations needed in the optimization process and runtime of the whole process in ILT are reduced by 70.8%and 69.0%, respectively.     

Functionally heterogeneous porous scaffold design for tissue engineering

Porous scaffolds with interconnected and continuous pores have recently been considered as one of the most successful tissue engineering strategies. In the literature, it has been concluded that properly interconnected and continuous pores with their spatial distribution could contribute to perform diverse mechanical, biological and chemical functions of a scaffold. Thus, there has been a need for reproducible and fabricatable scaffold design with controllable and functional gradient porosity. Improvements in Additive Manufacturing (AM) processes for tissue engineering and their design methodologies have enabled the development of controlled and interconnected scaffold structures. However homogeneous scaffolds with uniform porosity do not capture the intricate spatial internal micro architecture of the replaced tissue and thus are not capable of capturing the design. In this work, a novel heterogeneous scaffold modeling is proposed for layered-based additive manufacturing processes. First, layers are generated along the optimum build direction considering the heterogeneous micro structure of tissue. Each layer is divided into functional regions based on the spatial homogeneity factor. An area weight based method is developed to generate the spatial porosity function that determines the deposition pattern for the desired gradient porosity. To design a multi-functional scaffold, an optimum deposition angle is determined at each layer by minimizing the heterogeneity along the deposition path. The proposed methodology is implemented and illustrative examples are also provided. The effective porosity is compared between the proposed design and the conventional uniform porous scaffold design. Sample designed structures have also been fabricated with a novel micro-nozzle biomaterial deposition system. The result has shown that the proposed methodology generates scaffolds with functionally gradient porosity.     

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.     

基于增强现实的骨缺损修复系统原型设计

结合现有骨支架设计系统和增强现实交互技术,提出一种用于骨缺损修复手术的辅助规划方法与检查系统框架。对其中的显示合成与交互方式进行阐述,并以此为基础开发原型系统,其主要目的是在完成骨支架结构模型设计后,帮助临床医生在快速成形制作的颅骨模型上检验骨支架设计的合理性,完成手术的规划和仿真过程。     

FDM复合式路径填充的生成与优化

熔融沉积制造(FDM)是一种用填充方式来得到每层截面的快速成型工艺,由于成型轨迹的走向直接影响到成型件的外观和成型效率,因此选择一种好的成型算法格外重要。在目前现有的成型轨迹中,复合式扫描法由于在制件精度和加工效率上的诸多优势,成为研究的热点。基于分形填充和偏置填充本身所具有的优点,提出了一种复合优化轨迹的方法,并用分而治之算法对生成的路径进行了最大程度的优化,以减少喷头的开关次数和拉丝现象,保证制件的成型精度和强度,并且已成功应用在实际加工中。     

45 t岸边集装箱起重机可视化装配仿真

为缩短岸边集装箱起重机生产制造过程中的装配周期并降低成本,针对某45 t岸边集装箱起重机,基于面向装配设计的方法引入可视化虚拟装配技术,运用CATIA对其进行虚拟装配仿真分析,确定零部件装配层次关系,设计零件的部装、预拼装和总装等部分的整体装配流程.在CATIADMU平台建立基于仿真试拆卸的装配路径规划流程,并以运行小车滑轮组为例分析装配路径规划并进行装配干涉检查.该方法可以直观地显示出各零部件的可装配性,优化岸边集装箱起重机装配结构.     

Recent development on computer aided tissue engineering--a review.

The utilization of computer-aided technologies in tissue engineering has evolved in the development of a new field of computer-aided tissue engineering (CATE). This article reviews recent development and application of enabling computer technology, imaging technology, computer-aided design and computer-aided manufacturing (CAD and CAM), and rapid prototyping (RP) technology in tissue engineering, particularly, in computer-aided tissue anatomical modeling, three-dimensional (3-D) anatomy visualization and 3-D reconstruction, CAD-based anatomical modeling, computer-aided tissue classification, computer-aided tissue implantation and prototype modeling assisted surgical planning and reconstruction.     

基于医学图像序列面绘制的骨组织快速成型方法

针对人工骨组织快速成型中轮廓线轨迹生成复杂、分层效率低的问题,提出了一种简化三角片模型分层过程的方法。应用移动立方块（MC）算法对医学图像序列进行面绘制重建,根据重建过程的顺序对三角片集合分组,然后采用对边追踪的方法计算切平面与其对应三角片数组的交点轮廓线数据。简化后的分层效率相对于三角网格文件（STL）模型分层平均提高了4.65%。实验结果表明,所提方法可以直接从人体骨组织医学图像序列生成可供3D打印的轮廓线数据,从而实现骨组织的快速成型。     

Internal architecture design and freeform fabrication of tissue replacement structures

Modeling, design and fabrication of tissue scaffolds with intricate architecture, porosity and pore size for desired tissue properties presents a challenge in tissue engineering. This paper will present the details of our development in the design and fabrication of the interior architecture of scaffolds using a novel design approach. The interior architecture design (IAD) approach seeks to generate layered scaffold freeform fabrication tool path without forming complicated 3D CAD scaffold models. This involves: applying the principle of layered manufacturing to determine the scaffold individual layered process planes and layered contours; defining the 2D characteristic patterns of the scaffold building blocks (unit cells) to form the Interior Scaffold Pattern; and the generating the process tool path for freeform fabrication of these scaffolds with the specified interior architecture. Feasibility studies applying the IAD algorithm to example models with multi-interior architecture and the generation of fabrication planning instructions will also be presented.     

基于机器人弧焊的快速金属模型模具制造

基于分层制造概念的纯金属模型的制造是当今快速成型领域的热门研究课题 .机器人焊接是一种可以实现精密焊接的焊接方法 ,将机器人弧焊与分层制造结合即实现了金属模型甚至模具的快速制造 .本文论述了工作过程的基本概念和主要工作难点 ,指明了研究过程中的努力方向     

A model-based computer-aided prototyping system

Computer aided prototyping systems which allow application domain experts to compose prototypes using domain specific components, semantics, and primitives can reduce the time and effort needed for prototyping considerably.The notion of domain model is introduced as a vehicle for defining, generating, and categorizing domain specific components. Facilities to compose the components generated from the domain model to implement complex functionality are presented.A rapid prototyping system which provides a domain modeling tool and a visual direct manipulation composition tool is described. The main element of the domain modeling tool is a domain modeling language which provides: (i) a class construct to define object, (ii) rule, trigger, event, and relationship constructs to define interactions among objects, and (iii) process, task, and signal constructs to define the activities in the domain.The composition tool is the extension of a visual tool called IntelligentPad (IP) which supports unified data and control flows through a simple paste and connect metaphor. Domain models are translated to generate components, which are then composed using the extended IP.