Roberto Silvio Ubertino Rosso

CAD/CAM solutions for STEP-compliant CNC manufacture

The ability to generate an NC tool path is now commonplace in CAD/CAM systems, but the technology used for programming and control of NC machines is still based on 1950s standards. Today, under the IMS project called STEP-NC in Europe and Asia, and Super Model in USA, industrialists and academics are collaborating to deliver a new data model as an ISO 14649 standard for CNC machines. This standard will enable software vendors to revolutionize the programming of these machines. This paper provides a futuristic view of how this standard could be used in manufacturing and highlights a number of possible generic frameworks for how CAD/CAM systems may evolve using the ISO 14649 standard. Finally, the paper proposes a prototype STEP-compliant CAD/CAM system based on one of these frameworks using the new ISO 14649 standard for milling components.

Integrating the CAx process chain for STEP-compliant NC manufacturing of asymmetric parts

Acceleration of product development, decrease of NC programming effort and increase of product quality are demands from enterprises to make their products competitive. These requirements are hardly met by the todays used CAx process chain which is based on a multitude of interfaces and the standardized control data format ISO 6983. New concepts of product data modelling are necessary for a structured and object-oriented description of machining. The development of STEP-NC (ISO 14649) over the last ten years has brought new opportunities for automating the CAx process chain. The present paper portrays a methodology for implementation of a standardized CAx process chain for rotational asymmetric parts, which are described in the technology-oriented process model for turning (ISO 14649-12). The methodology is realized through a suite of STEP-compliant NC software tools, based on STEP-compliant information models to integrate the whole chain from design to machining. Component case studies are used to demonstrate and analyse the methodology. The final part of the paper discusses the major issues and deficiencies related to the current phase of development of this new approach.

Toward interoperable CNC manufacturing

Most manufacturing enterprises now employ compute numerical control (CNC) technology in their production chain. Improving the performance and flexibility of the computer aided design (CAD)/computer aided manufacturing (CAM)/CNC chain can therefore, have a significant effect on the competitiveness of such enterprises. Whereas hardware capabilities of these systems have increased proactively over the last few decades, the software components have been updated reactively to support the enhancements found on the newer generation of CNC machines. This passive approach has led to severe incompatibilities between the various CAD/CAM/CNC solutions. This paper presents the impediments and issues arising from such incompatibilities and proposes a new framework to overcome these barriers in achieving interoperability in the CAD/CAM/CNC chain. In the suggested framework different components of the CAD/CAM/CNC chain can exchange information with one another regardless of their native standards. The different elements comprising the framework are demonstrated by utilizing a test component in a dynamic manufacturing scenario.

The adoption of STEP-NC for the manufacture of asymmetric rotational components

Abstract This paper reports ongoing research on the use of the evolving ISO 14649 standard, informally termed STEP-NC, which represents a new data model for the next generation of computer numerical controllers. The paper presents the major challenges in implementing STEP-compliant CAD/CAM (computer-aided design/manufacture) systems for manufacturing asymmetric rotational parts. It also discusses the need for a new ISO 14649 schema specific for asymmetric rotational parts and outlines a feasible solution to use the ISO 14649 data model for turn/mill machining.

A Design for Assembly Application with Dynamic Information Retrieval from Case Database

Design for Assembly (DFA) is a Concurrent Engineering constituent that gained a lot of attention due to fast and measurable benefits. The main principle of DFA is to foresee assembly problems at the design stage based on the experience regarding functionality, materials and machine availability. The work presented in this paper, named RFA - Redesign for Assembly, adds a way to explicitly register and retrieve experiences as part of the design process. It starts from an initial design, then RFA leads the designer through a detailed assessment towards an improved design according to previous experiences. Experience representation was done using a Group Technology classification concept that helps assign a primary-key for a Case Based Teaching underlying system. A supporting system has been implemented in order to try out RFA. DFA scholars have used RFA and proved that experience retrieval is easily and intuitively incorporated in the design process. The paper presents a study about the DFA methodology, reviews existing solutions (methods and software) from the literature and details the RFA architecture, implementation and tests. RFA shows potential for a new design culture based on knowledge sharing, but also, as a repository for a very valuable asset, i.e. problem-oriented assembly-related design experience.

ICARU-FB: An IEC 61499 Compliant Multiplatform Software Infrastructure

This paper presents the proposal and implementation of I CAN RUn - Function Blocks (ICARU-FB), a multiplatform environment capable of running the function blocks defined in IEC 61499 on architectures with few computational resources. A virtual machine was designed and implemented to perform networks of function blocks on 8-bit platforms with minimal resources. It was also reported to run on a 64-bit computer. Two case studies were performed in order to verify compliance with IEC 61499. Through the case studies, it was verified that it is possible to meet the requirements of the standard, such as configurability, interoperability, and portability. The case studies also demonstrated the ability of the environment to reconfigure the software at runtime.

Diaphragmatic Surface Reconstruction from Massive Temporal Registration of Orthogonal MRI Sequences

Abstract The diaphragm is an important component of the respiratory pumping process. Orthogonal temporal sequences of MR images are acquired in free breathing without use of contrast. The vertical intersection between two orthogonal temporal sequences is determined, the diaphragmatic level in the vertical segment is determined and used to perform the temporal registration. Previous works used similar temporal registration algorithms to reconstruct the diaphragmatic surface. However, it is shown that the available information was not efficiently used. The proposed method massively performs temporal registrations, and then validates the determined temporal registrations. The images to be used in the diaphragmatic surface reconstruction are determined and its associated diaphragmatic levels are collected. Positions with inconsistencies have their diaphragmatic level determined by interpolation. The proposed algorithm is tested with MR image sequences obtained from a healthy subject.

Bézier Curve Fitting with a Parallel Differential Evolution Algorithm

The curve fitting problem is present in several areas, including signal processing, statistics and geometric modeling. Computationally expensive algorithms were proposed to solve this problem, some using artificial intelligence. A previous work implemented a sequential Differential Evolution (DE) algorithm to solve the problem of Bezier Curve Fitting. This work implements and analyzes a solution to approximate Bezier curves using a parallel Differential Evolution algorithm. Tests were performed to verify the objective function in several generations of the DE algorithm, as well as an analysis of this solutions speedup and parallel efficiency.

Safe dynamic reconfiguration through supervisory control in IEC 61499 compliant systems

Dynamic reconfiguration enables automation and control systems to be reconfigured without the need to completely stop. With this feature, automation and control systems can adapt to new requirements as well as enable upgrades and maintenance quickly. This work proposes a methodology for the execution of dynamic reconfiguration in systems whose dynamics is driven by the occurrence of discrete events. Applying the theory of supervisory control, a methodology was developed to allow the change of the system control logic at runtime, ensuring the global and local consistency of the application. Next, the use of the methodology proposed in systems compliant with IEC 61499 standard is presented.

Lung segmentation of sagittal and coronal MR images using morphological operations

In this work, segmentation is an intermediate step in the registration and 3D reconstruction of the lung. New MR imaging protocols have been used to enhance the lung internal structures and, consequently, the lung boundary is weakened. This fact turns the segmentation of lung MR images particularly difficult. The algorithm proposed herein uses morphological operators to segment sagittal and coronal lung MR images. The algorithm is tested with several sagittal and coronal temporal sequences of MR images. Using the resulting segmentation, lung masks are created to determine the region with high probability where the lung contour is. The masks were used in a temporal segmentation algorithm based on Hough transform to determine the lung boundary with higher precision. The results showed to be robust and consistent under the MR temporal image sets tested.