Virtual Manufacturing Tools Research Articles

Robust and Fast 3-D Saliency Mapping for Industrial Modeling Applications

New generation 3-D scanning technologies are expected to create a revolution at the Industry 4.0, facilitating a large number of virtual manufacturing tools and systems. Such applications require the accurate representation of physical objects and/or systems achieved through saliency estimation mechanisms that identify certain areas of the 3-D model, leading to a meaningful and easier to analyze representation of a 3-D object. 3-D saliency mapping is, therefore, guiding the selection of feature locations and is adopted in a large number of low-level 3-D processing applications including denoising, compression, simplification, and registration. In this article, we propose a robust and fast method for creating 3-D saliency maps that accurately identifies sharp and small-scale geometric features in various industrial 3-D models. An extensive experimental study using a large number of 3-D scanned and CAD models verifies the effectiveness of the proposed method as compared to other recent and relevant approaches despite the constraints posed by complex geometry patterns or the presence of noise.

Investigation on Welded T-Joint Distortion Using Virtual Manufacturing Tools with Simplified Procedure

This study presents a distortion analysis of a welded T-joint by using the virtual manufacturing (VM). Two different nonlinear 3D FEM-based VM systems, namely the general purpose MSC Marc/Mentat and the specialized Simufact.Welding software are compared and verified with the experiment. Both simulations are conducted based on an uncomplicated procedure without considering enormously on the weldment shape and resulting transient temperature distribution. Within this VM procedure, the heat source is modeled following Goldak’s double ellipsoid and the flow curve as one of the material properties of low carbon steel S235 is added with only one strain rate (0.001 s) based on non-linear isotropic plasticity model and von-Mises yield stress criterion. As the final outcome, the simplified procedures, weld geometry, and material properties will reduce the pre-processing without deteriorating the distortion results tremendously. Welding provides more structured and clearer simulation steps with more precise results of the angular distortion (Average of 7.25%) compared to the general purpose MSC Marc/Mentat (Average of 14.5%). This simplified simulation procedure without heat source and temperature calibration as well as complex material properties can be recommended for implementation if the time matter is constrained and the results are expected to be moderate.

Automatic Modeling and Simulation of Robot Program Behavior in Integrated Virtual Preparation and Commissioning

This paper presents a method where the behavior of a robot cell is automatically modeled based on existing robot programs and a simulation model of the cell. Robot programs from the shop floor are uploaded into a virtual manufacturing tool, and a formal model is then generated from the robot programs. Then, control logic is automatically calculated, and the fastest possible execution order is found by using the generated model to formulate an optimization problem. The result is continuously analyzed and validated by simulation in the virtual manufacturing tool.

Virtual Manufacturing concepts reducing the Flow Time in Aircraft Manufacturing

The high cost and long lead times of traditional manufacturing makes it difficult for manufactures to efficiently meet eternally changing market demands. In order to determine the manufacturability of the component and low cost production of aircraft manufacturing, Digital Virtual Manufacturing plays a vital role. By the advancement in technologies like Virtual Manufacturing tools used through Product Lifecycle Management (PLM), are competent to access and reuse the best practices, as well as evaluate 3-D manufacturing scenarios. By implementing advance 3-D CAD systems with the CNC machines enables the success of the determinate assembly approach to significantly reduce the lead time aircraft manufacturing. This paper encompasses the virtual manufacturing concept to enable complex manufacturing set-up analysis, exchanging expertise at collaborative work. Virtual Manufacturing is using the manufacturing knowledge at PLM environment for defining the assembly process of an aircraft parts.

ErgoToolkit: an ergonomic analysis tool in a virtual manufacturing environment

The virtual manufacturing tools are usually equipped with digital human models for the simulation of manufacturing tasks. This enables designers to analyse alternative design solutions and to obtain ergonomic performance measures. An ergonomic assessment requires the availability of ergonomic analysis tools integrated into the virtual manufacturing process. This article presents ErgoToolkit, which implements ergonomic analysis methods, already available in literature or company practice, into digital tools for ergonomics, integrated into state-of-the-art virtual manufacturing software. These ergonomic tools are: the Posture Definition and Recognition and the Stress Screening. The former provides the functionality of defining and automatically recognising digital human postures, while the latter objectively evaluates ergonomically any unfavourable situations in a manual work process. It is shown that they are viable tools in detecting ergonomic problems, early in a development process, prior to physical installation. The benefits of the tools with the existing industrial practice are discussed. This article also describes technical implementation issues along with the application of the tools in an automotive case study.

Automatic assembly path planning for wiring harness installations

The automotive industry of today is becoming more focused on electrified and hybrid solutions, where both conventional combustion engines and battery supplied electrical engines need to fit in an already densely packed vehicle. Many quality problems are related do flexible parts. In particular, the assembly of electric cables and wiring harnesses is difficult due to its concealed routing, multiple branching points, weights and the flexibility in the material. To avoid late detection of assembly problems, the assembly aspect must be considered early during conceptual design and production preparation with respect to both feasibility and ergonomics. Development of automatic path planning methods in virtual manufacturing tools supporting deformable parts is therefore highly motivated.This article presents a novel method for automatically planning and finding a smooth and collision-free mounting of connectors in a wiring harness installation. Automatic path planning for deformable objects in general is widely acknowledged as a very difficult problem. To overcome this challenge, we propose a low-dimensional path planning algorithm that operates in the following way: constraint relaxation, handle path planning, unfolding, path smoothing and handle supplementation. The method has been implemented and successfully applied to an industrial test case.

Evolutionary optimization of robotic assembly operation sequencing with collision-free paths

Many problems in the lifecycle of product and production development (PPD) can be formulated as optimization problems. But in most of the real-world cases, they are too complex to be solved by analytical models or classical optimization methods. CAx and virtual manufacturing (VM) tools are on the other hand being employed to create virtual representation of products and processes before any physical realization is conducted. Synergy of these two domains is of interest in this paper where planning a process with the minimum cycle-time for assembling a spot welded sheet-metal product is desired. The methodology suggests an extendible virtual manufacturing-based optimization approach using evolutionary algorithms. Accordingly, a novel toolset with integration of evolutionary optimization and a commercial VM environment is developed. More specifically, the latest feature which takes advantage of the collision avoidant segment path planning functionality of the VM tool and integrates it with the sequence optimizer is described.

Planning transport sequences for flexible manufacturing systems

AbstractWhen designing a manufacturing system it is important to plan what the system should do. One important activity in most manufacturing systems is to transport products or resources between different positions. In a flexible manufacturing system it can be challenging to design and plan these transport operations due to their complex logical behavior. This paper presents a method that identifies, creates and visualizes these transport operations based on inputs from a standard virtual manufacturing tool and a high level product operation recipe. The planning of the created transport operations is transformed into a problem of finding a non-blocking solution for a discrete model of the product refinement.

Virtual Commissioning of Modular Automation Systems

A new concept in modular automation systems and their virtual engineering is presented. The new approach is aimed to provide support for the reconfigurable manufacturing systems (RMS) approach to automation. Manufacturing industries are moving to the concept of RMS to fulfill the great demand to deliver greater levels of product customisation at a higher quality and at reduced cost. RMS allows the manufacturing companies to quickly implement innovative design changes in their products and produce a greater number of product variants on leaner production lines with shorter times to market. The aim of this research is to enable production machines to be more easily and cost effectively built and subsequently reconfigurable through the adoption of a component-based approach to their implementation utilising virtual manufacturing tools. It is proposed that through the decomposition of manufacturing machines into standardized mechanisms and their associated data structures, a RMS can be designed and implemented. Research conducted at Loughborough University into the development of concepts and tools to support the global engineering of component-based reconfigurable manufacturing automation systems in the automotive production domain is described in this paper. A collaborative framework to integrate and coordinate the various engineering activities of globally distributed engineering teams involved in the design, implementation, operation and diagnosis of production machinery is also described.

Process Modeling for Precision Forming of Discrete Parts – State of the Technology and Critical Issues

This paper presents an overview on the application of FE simulation as a virtual manufacturing tool in designing manufacturing processes for precision parts. The processes discussed include forging, sheet metal forming and hydroforming. Determination of reliable input parameters to simulate a process is a key element in successful application of process simulation for process design in all the mentioned areas. These issues are discussed in detail. Practical examples of application of FE simulation are presented for improvement of the existing metal forming process and/or designing new metal forming process for manufacturing discrete precision parts in forging, sheet metal forming and hydroforming.

Development and Pilot Testing for Virtual Manufacturing Tools with Intelligent Attributes

Abstract The use of synthetic and surrogate tools in training robots and planning events within virtual environments has tremendous potential in making the programming of complex machines simple and easy. For example, by designating tasks off-line with the virtual tools, attributes such as process planning and collision avoidance can be automatically and efficiently incorporated. In our research we have experimented with the use of attribute laden virtual tools in various tasks such as robotic-based grinding and welding processes. Such attribute laden virtual tools aid human operators in path planning as well as in making decisions about the process itself. In this paper we have tested our concepts of virtual tools and the use of attributes such as physical, reflex and command actions. Four sets of experiments were conducted with human subjects. Two kinds of virtual tools were used in these experiments, one with guide plane attributes and the other without them. One set of experiments using the head mounted display interface, tested human performance and evaluated the effect of the learning process in using the virtual tools. Results showed that there was marked improvement in task execution time using the tools laden with guide plane attributes over the unencumbered virtual tools. This paper discusses various future applications of these virtual tools in manufacturing. It is observed that unlike non-haptic visual interfaces, where no physical feed back is available to the user, attribute laden tools could provide a much easier interface to robots.

Development and pilot testing for virtual manufacturing tools with intelligent attributes

The use of synthetic and surrogate tools in training robots and planning events within virtual environments has tremendous potential in making the programming of complex machines simple and easy. For example, by designating tasks off-line with the virtual tools, attributes such as process planning and collision avoidance can be automatically and efficiently incorporated. In our research we have experimented with the use of attribute laden virtual tools in various tasks such as robotic-based grinding and welding processes. Such attribute laden virtual tools aid human operators in path planning as well as in making decisions about the process itself. In this paper we have tested our concepts of virtual tools and the use of attributes such as physical, reflex and command actions. Four sets of experiments were conducted with human subjects. Two kinds of virtual tools were used in these experiments, one with guide plane attributes and the other without them. One set of experiments using the head mounted display interface, tested human performance and evaluated the effect of the learning process in using the virtual tools. Results showed that there was marked improvement in task execution time using the tools laden with guide plane attributes over the unencumbered virtual tools. This paper discusses various future applications of these virtual tools in manufacturing. It is observed that unlike non-haptic visual interfaces, where no physical feed back is available to the user, attribute laden tools could provide a much easier interface to robots.

DISTRIBUTED VIRTUAL MANUFACTURING FOR DEVELOPMENT OF MODULAR MACHINE SYSTEMS

To support all phases of an agile modular manufacturing machine life cycle with CAE and Virtual Manufacturing tools, a number of different engineering applications (e.g. specialist software based tools) are typically used for design, simulation, analysis, programming, control and monitoring of a machine. These applications mainly exist today as small applications islands where each of them manages their own data. When a manufacturing machine is designed, simulated, programmed, analyzed, tested, or operated, the information, connected to that specific machine, used and generated by each application island is stored separately by each application. These application islands often use different storage technologies. Each one of the applications has an information structure to separate the information connected to each machine; however, they do not necessarily use the same information structure. Another issue concerning these applications is the functionality that is implemented in them to manage information; namely, processes such as store, retrieve, search, permissions, etc. The functionality for one process is the same in all applications that has the process implemented. But the implementation of the process functionality may differ, due to misinterpretation of the functionality specification and regular implementation bugs, which could lead to problem with integrity and consistency of the data. Applications that make use of newer information technologies, such as databases and software development tools can simplify the implementation of the functionality but each application still has to implement their own version of the functionality. This paper presents a research investigation focused on the development of a distributed integration platform that supports the whole life cycle of agile modular machine systems, which includes the design, simulation, programming, analysis, machine operation and re-configuration. The environment supports distributed management and storage of information in a system-wide library, information management and storage that is machine oriented, not application oriented, and information storage structured as reusable components to enable reuse of information and know-how that is produced throughout the life cycle of machines.