Automated Posture Positioning for High Precision 3D Scanning of a Freeform Design using Bayesian Optimization

Three-dimensional scanning is widely used for the dimension measurements of physical objects with freeform designs. The output point cloud is flexible enough to provide a detailed geometric description for these objects. However, geometric accuracy and precision are still debatable for this scanning process. Uncertainties are ubiquitous in geometric measurement due to many physical factors. One potential factor is the object’s posture in the scanning region. The posture of target positioning on the scanning platform could influence the normal of the scanning points, which could further affect the measurement variances. This paper first investigates the geometric and spatial factors that could potentially influence scanning variance. This functional relationship is modeled as a Bayesian extreme learning model, which is later utilized to find the object’s optimal posture for variance reduction. A Bayesian optimization approach is proposed to solve this minimization problem. Case studies are presented to validate the proposed methodology

On The Use Of Students For Developing Engineering Laboratories

This paper describes a unique and innovative approach that solved the dual problem of starting up a new engineering instructional laboratory in a timely manner, and for teaching engineering students advanced skills in Automatic Data Collection. Students enrolled in a special pilot course were used to develop and startup an Automatic Data Collection laboratory. These students were assigned individual Automatic Data Collection technologies of interest and given total responsibility for the successful startup of the laboratory. The organization and structure of the course modeled the typical team oriented project development efforts in industry. Feedback from students showed the course to be better than a typical lecture/laboratory/demonstration type course in the following ways: 1) students believed they had greater amount of contact with equipment; 2) their experience on the project was more realistic than more traditional courses; 3) they believed they gained a more thorough understanding of the technology under study; and 4) they believed they improved their professional skills making them more marketable to potential employers. With respect to the laboratory itself, startup time was reduced from an estimated 18 months to 14 weeks with the help of the student teams. 1995 American Society for Engineering Educatio

Minimax Registration for Point Cloud Alignment

The alignment, or rigid registration, of three-dimensional (3D) point clouds plays an important role in many applications, such as robotics and computer vision. Recently, with the improvement in high precision and automated 3D scanners, the registration algorithm has become critical in a manufacturing setting for tolerance analysis, quality inspection, or reverse engineering purposes. Most of the currently developed registration algorithms focus on aligning the point clouds by minimizing the average squared deviations. However, in manufacturing practices, especially those involving the assembly of multiple parts, an envelope principle is widely used, which is based on minimax criteria. Our present work models the registration as a minimization problem of the maximum deviation between two point clouds, which can be recast as a second-order cone program. Variants for both pairwise and multiple point clouds registrations are discussed. We compared the performance of the proposed algorithm with other well-known registration algorithms, such as iterative closest point and partial Procrustes registration, on a variety of simulation studies and scanned data. Case studies in both additive manufacturing and reverse engineering applications are presented to demonstrate the usage of the proposed method

Colombia & the New Global Economy: Implications of Tratado de Libre Comercio for Colombian Industry, Engineers and Engineering Educators

The landscape of the world economy has changed significantly over the last twenty five years. The inter-connectedness of national economies, the rapid ascent of the BRIC countries (Brazil, Russia, India, China) in the global engineering environment and the pro-active role of organizations such as the World Trade Organization, regional alliances such as the EU, and Mercosur are factors that have synergized this movement towards a new order. The completion of the Tratado de Libre Comercio (TLC) agreement is a major milestone for the Colombian economy. These developments have serious and opportunistic implications for organizations, engineers, and engineering educators. We focus here on the drivers and consequences for engineering practitioners and educators. Corporate strategies, along with the need for engineering curriculum reform to ensure that Colombian engineers will effectively compete in the global marketplace, are detailed

A Survey of Smart Manufacturing for High-Mix Low-Volume Production in Defense and Aerospace Industries

Defense and aerospace industries usually possess unique high-mix low-volume production characteristics. This uniqueness generally calls for prohibitive production costs and long production lead-time. One of the major trends in advanced, smart manufacturing is to be more responsive and better readiness while ensuring the same or higher production quality and lower cost. This study reviews the state-of-the-art manufacturing technologies to solve these issues and previews two levels of flexibility, i.e., system and process, that could potentially reduce the costs while increasing the production volume in such a scenario. The main contribution of the work includes an assessment of the current solutions for HMLV scenarios, especially within the defense of aerospace sectors, and a survey of the current and potential future practices focusing on smart production process planning and flexible assembly plan driven by emerging techniques

A Market Analysis on Green Production Lines Penetrating into Original Equipment Manufacturers (OEMs)

Fierce market competition has been big obstacle in the growth process of sustainable/green production industry. Sustainable production lines often come into play by penetrating into traditional Original Equipment Manufacturers (OEMs). This is due to the high setup cost and opportunity risks. In this study, we look into the scenario when traditional Original Equipment Manufacturers (OEMs) introduce green production lines into their production systems. We want to address the questions whether and how the green production lines can survive in the market competitions. Analyses are conducted between ordinary and green production sectors which produce a similar type of product with different materials and techniques. A game theoretic model is formulated to analyze the competition in the market. Sensitivity analyses and numerical examples can provide suggestions to assist policy makers, government, company executives and consumers to make better and rational decisions

An Oligopoly Model to Analyze the Market and Social Welfare for Green Manufacturing Industry

As public concerns on sustainable economic development increase, an increasing number of manufactured products have found their environmentally preferable alternatives. In this study, we propose an oligopoly game theoretical model to analyze the competition between the green and ordinary manufacturing sectors. We identify cost efficiency and innovative design as key elements to the survival of green products. We also find that the effectiveness of Pigouvian tax and subsidy policies depend on product characteristics, market structures, as well as targeted results. Our small empirical examples on Corolla vs. Prius and Incandescent lamp vs. Compact fluorescent lamp (CFL) show that our modeling results are more optimistic than real market statistics. We identify pre-equilibrium market dynamics, consumer bias towards green products, and modeling limitations as the main reasons for such differences. We also investigate the market competition and total societal welfare in the presence of tax and subsidy policy intervention. The study results not only provide guidelines and managerial insights for green producers to understand the underlying factors that determine the competitiveness of green products in the market but also benefit policy makers by quantitatively showing the effectiveness of tax and subsidy policies in promoting green products

Attribute-level Neighbor Hierarchy Construction Using Evolved Pattern-based Knowledge Induction

Neighbor knowledge construction is the foundation for the development of cooperative query answering systems capable of searching for close match or approximate answers when exact match answers are not available. This paper presents a technique for developing neighbor hierarchies at the attribute level. The proposed technique is called the evolved Pattern-based Knowledge Induction (ePKI) technique and allows construction of neighbor hierarchies for nonunique attributes based upon confidences, popularities, and clustering correlations of inferential relationships among attribute values. The technique is applicable for both categorical and numerical (discrete and continuous) attribute values. Attribute value neighbor hierarchies generated by the ePKI technique allow a cooperative query answering system to search for approximate answers by relaxing each individual query condition separately. Consequently, users can search for approximate answers even when the exact match answers do not exist in the database (i.e., searching for existing similar parts as part of the implementation of the concepts of rapid prototyping). Several experiments were conducted to assess the performance of the ePKI in constructing attribute-level neighbor hierarchies. Results indicate that the ePKI technique produces accurate neighbor hierarchies when strong inferential relationships appear among data. © 2006 IEEE

Emerging Trends In Reverse Engineering

This paper presents an overview of reverse engineering - an often ignored but critical part of additive manufacturing. The quality of a 3D printed part is limited by the quality of computer model that details the part, which in turn, is governed by the quality of the acquired data in the computer. Data is typically acquired by reverse engineering. While the discipline has progressed significantly over the past decade, there is still much to be done. This paper describes new trends in the field that include increased speed and accuracy and even explores exciting possibilities in the future.Published versio

Review of reverse engineering systems – current state of the art

Reverse engineering (RE) has been widely applied in many segments of industry when digital or geometric models of existing physical objects are unavailable. This paper details components of RE systems and describes the needs for RE in manufacturing industries. Commonly used contact and non-contact scanning techniques are described. Possible interfaces with other manufacturing processes, especially 3D printing (3DP), are discussed. This paper also describes new trends in the field that include increased speed, accuracy, and level of automation in the future. Finally, a discussion on two major tolerance issues in terms of integrating RE and 3DP are presented