Designing Product Forms Using a Virtual Hand and Deformable Models

This paper presents a computer-aided conceptual design system for developing product forms. The system integrates a virtual hand, which is manipulated by the designer, with deformable models representing the product forms. Designers can use gestural input and full hand pointing in the system to discover potential new ways for product form design. In the field of industrial design, styling and ergonomics are two important factors that determine a successful product design. Traditionally, designers explore possible concepts by sketching their ideas and then using clay or foam mock-ups to test them during the early phases of product design. With our deformable modeling simulation system, we provide a useful and efficient tool for industrial designers that enable to produce product form proposals efficiently without unnecessary trial and error. Designers can input pre-scanned 3D raw data or a 3D CAD model as an initial prototype. Then, the input model is given the material’s elastic property via the construction of a volume-like mass-spring-damping system. The virtual hand in the system constantly changes gestures as the designer manipulates it with a glove-based input device. The product form will be deformed or shaped according to the amount of force exerted by the virtual hand. A mesh smoothing feature called “PN-triangle” is also used to improve the appearance of the deformed model. Finally, a physical prototype with volume and weight is generated using a rapid prototyping machine. Designers can use these mock-ups to conduct further ergonomic evaluations.

Multi-Agent Form Closure Capture of a Generic 2D Polygonal Object Based on Projective Path Planning

The study of multi-agent capture and manipulation of an object has been an area of active interest for many researchers. This paper presents a novel approach using Genetic Algorithm to determine the optimal contact points and the total number of agents (mobile robots) required to capture a stationary generic 2D polygonal object. After the goal points are determined the agents then reach their respective goals using a decentralized projective path planning algorithm. Form closure of the object is obtained using the concept of accessibility angle. The object boundary is first expanded and the robots reach the expanded object goal points and then converge on the actual object. This ensures that the agents reach the actual goal points at the same time and have the correct orientation. Frictionless point contact between the object and robots is assumed. The shape of the robot is considered a circle such that it can only apply force in outward radial direction from its center and along the normal to the object boundary at the contact point. Simulations results are presented that prove the effectiveness of the proposed method.

A Generic, Geometric Approach to Accurate Machining-Error Predictions for 3-Axis CNC Milling of Sculptured Surface Parts: Part I — Modeling and Formulation

In CNC machining, machining errors are usually caused by some of the sources such as cutting tool deflection, cutting tool wear, machine tool vibration, improper coolant/lubrication, and negative thermal effect. To increase product accuracy, much research has been carried out on the prediction of machining errors. However, in milling of sculptured surface parts, due to their curved shapes, the geometries of cutting tools do not match the parts’ surfaces well if the tools cut along the tool paths on the surfaces in a point-to-point way. As a consequence, machining error is inevitable, even if there is no other source of error in ideal machining conditions. To predict machining errors caused by this tool-surface mismatch, several methods have been proposed. Some of them are simple, and some represent the geometry of machined surfaces using cutter-swept surfaces. But none of these methods is accurate and practical. In this research work, a generic, geometric approach to predicting machining errors caused by the tool-surface mismatch is proposed for 3-axis sculptured surface milling. First, a new geometric model of the furrow formed by an APT tool moving between two neighboring cutter contact (CC) points is built. Second, the mathematical formula of cutting circle envelopes is derived. Then an algorithm for calculating machining errors in each tool motion is provided. Finally, this new approach is applied to two practical parts for the accurate machining-error predictions, and these predictions are then compared to the inaccurate predictions made by two established methods to demonstrate the advantages of this approach. This approach can be used in tool path planning for high precision machining of sculptured surface parts.

SHARP: A System for Haptic Assembly and Realistic Prototyping

Virtual Reality (VR) technology holds promise as a virtual prototyping tool for mechanical assembly; however, several developmental challenges still need to be addressed before virtual prototyping applications can successfully be integrated into the product realization process. This paper describes the development of SHARP (System for Haptic Assembly & Realistic Prototyping), a portable VR interface for virtual assembly. SHARP uses physically-based modeling for simulating realistic part-to-part and hand-to-part interactions in virtual environments. A dual handed haptic interface for realistic part interaction using the PHANToM® haptic devices is presented. The capability of creating subassemblies enhances the application’s ability to handle a wide variety of assembly scenarios. Swept volumes are implemented for addressing maintainability issues and a network module is added for communicating with different VR systems at dispersed geographic locations. Support for various types of VR systems allows an easy integration of SHARP into the product realization process resulting in faster product development, faster identification of assembly and design issues and a more efficient and less costly product design process.

A Benchmark Comparison of Coupled and Segregated Iterative SUPG Finite Element Formulation for Incompressible Flow

In fluid flow and heat transfer, the finite element based fully coupling solution for all conservation equations is cost effective for most of the two dimensional, isothermal problems, but suffers in the storage and solution efficiency for large three dimensional problems. The segregated solution algorithm has been designed to address large scale simulation with avoiding the direct formulation of a global matrix. There is trade-off between performing a large number of less expensive iterations by segregated solvers compared to less number of more expensive fully coupled solvers. In this paper, a Finite Element based scheme based on preconditioned GMRES coupled algorithm and SUPG (Streamline Upwind Petrov-Galerkin) pressure prediction/correction segregated formulations have been discussed to solve the steady Navier-Stokes equations. A systematic comparison and benchmark between the segregated and fully coupled formulation has been presented to evaluate the individual benefits and strengths of the coupling and segregated procedure by studying lid-driven cavity problem and large industry application problem with respect to the system storage and solution convergence.

Formulating and Searching Assembly Sequence Design Spaces to Increase the Utilization of Current Assembly Plant Resources

Efficient procedures for generation of feasible assembly sequences and effective utilization of available assembly plant resources can greatly reduce the development time and cost for platforms for the new product family members. This paper presents a method application to generate feasible assembly sequences and an approach to select an assembly process that reduces the existing plant modification cost. Assembly sequence design space is combinatorial in nature. Mathematical models to solve the effects of constraints on these spaces and algorithms to efficiently enumerate feasible spaces are presented. An algorithm that selects assembly process that can reduce the modification cost of the existing assembly plant is developed. A software application that implements the method and algorithms is also presented. The program uses the concept of recursive partitioning of set of components to generate assembly sequence space. The assembly processes are then evaluated to determine the process that maximized resource utilization. The application of the proposed approach and software is demonstrated using automotive underbody front structure product family.

LEA: Software System for Multimedia and Virtual-Reality Web-Based Education and Training

LEA (Learning Environments Agent) is a web-based software system for advanced multimedia and virtual-reality education and training. LEA consists of three fully integrated components: (1) unstructured knowledge-base engine for lecture delivery; (2) structured hierarchical process knowledge-base engine for step-by-step process training; and (3) hierarchical rule-based expert system for natural-language understanding. In addition, LEA interfaces with components which provide the following capabilities: 3D near photo-realistic interactive virtual environments; 2D animated multimedia; near-natural synthesized text-to-speech, speech recognition, near-photorealistic animated virtual humans to act as instructors and assistants; and socket-based network communication. LEA provides the following education and training functions: multimedia lecture delivery; virtual-reality based step-by-step process training; and testing capability. LEA can deliver compelling multimedia lectures and content in science fields (such as engineering, physics, math, and chemistry) that include synchronized: animated 2D and 3D graphics, speech, and written/highlighted text. In addition, it can be used to deliver step-by-step process training in a compelling near-photorealistic 3D virtual environment. In this paper the LEA system is presented along with typical educational and training applications.

Design of Oxidizer Referenced Fuel Pressure Regulator

This research involves the development and testing of a pressure regulator designed to maintain a constant pressure and mass flow relationship between the oxidizer and fuel source of a nitrous oxide injection system. Regulator design was accomplished through the exhaustive process of reviewing various fuel control and oxidizer referencing designs coupled with finite element analysis on the oxidizer referenced components to determine whether the selected components could handle the relatively high forces generated by the 1000psi nitrous oxide. The testing phase of the project was done in a dynamometer cell and involved numerous dynamometer tests of an engine supplied with a nitrous oxide kit both with and without the oxidizer referenced fuel pressure regulator. These tests monitored critical areas such as peak cylinder pressure, the location of the peak cylinder pressure, the air/fuel ratio, the nitrous oxide bottle pressure, and the knock intensity. The data collected in each of these areas was used to compare the performance of a regulated and non-regulated system as well as ensure the safe and reliable operation of the engine.

Multidisciplinary Information Management for the Mechatronic Engineering of Assembly Systems

The mechatronic engineering of assembly systems is a multidisciplinary engineering process. In each engineering discipline one or more engineering tools are applied to support the discipline-specific engineering tasks. These engineering tools manage the engineering data separately and in different formats. Reuse and consistency of these engineering data across the whole development process is a main problem in today’s mechatronic engineering of assembly systems. This paper presents an approach of an extensible multidisciplinary information system in order to manage and share the engineering data in the entire engineering of assembly systems.

Industry-Academia Computer Aided Engineering Undergraduate Research Projects

Florida’s First Coast Manufacturing Innovation Partnership (MIP), sponsored by the National Science Foundation (NSF), promotes collaboration between academia and local industry members by providing a shared resource center. The local industry provides the university with research opportunities for its undergraduate students in areas of mechanical engineering design, manufacturing, and analysis and the university provides the local industry with technical resources. This paper outlines how this collaborative effort is structured, what types of projects are undertaken, and what the benefits are to academia, industry, and society in general. In particular, the paper describes three computer aided engineering (CAE) projects, addresses how these industry-academia projects help achieve the goals of the MIP program, and how these projects help improve the CAE skills of the future workforce.