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research-article  
Shrinath Deshpande and Anurag Purwar
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042325
Synthesizing circuit-, branch-, or order- defects-free planar four-bar mechanism for the motion generation problem has proven to be a difficult problem. These defects render synthesized mechanisms useless to machine designers. Such defects arise from the artificial constraints of formulating the problem as a discrete precision position problem and limitations of the methods which ignore the continuity information in the input. In this paper, we bring together diverse fields of pattern recognition, machine learning, artificial neural network, and computational kinematics to present a novel approach that solves this problem both efficiently and effectively. At the heart of this approach lies an objective function which compares the motion as a whole thereby capturing designer's intent. In contrast to widely used structural error or loop-closure equation based error functions which convolute the optimization by considering shape, size, position, and orientation of the given task simultaneously, this objective function computes motion difference in a form, which is invariant to similarity transformations. We employ auto-encoder neural networks to create a compact and clustered database of invariant motions of known defect-free linkages, which serve as a good initial choice for further optimization. In spite of highly nonlinear parameters space, our approach discovers a wide pool of defect-free solutions very quickly. We show that by employing proven machine learning techniques, this work could have far-reaching consequences to creating a multitude of useful and creative conceptual design solutions for mechanism synthesis problems, which go beyond planar four-bar linkages.
TOPICS: Linkages, Kinematics, Machine learning, Optimization, Artificial neural networks, Circuits, Databases, Errors, Pattern recognition, Shapes, Conceptual design, Machinery, Error functions
research-article  
Gaurav Ameta and Paul Witherell
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042327
Additive manufacturing (AM) has enabled control over heterogeneous materials and structures in ways that were not previously possible, including functionally graded materials and structures. This paper presents a novel method for representing and communicating heterogeneous materials and structures that include tolerancing of geometry and material together. The aim of the paper is to propose a means to specify nominal materials, nominal structures and allowable material variations in parts, including (a) explicit material and structural transitions and (b) functional transitions to support single and multiple material and structural behaviors. The transition region combines bounded regions (volumes and surfaces) and material distribution and structural variation equations. Tolerancing is defined at two levels, that of the geometry including bounded regions and that of the materials. Material tolerances are defined as allowable material variations from nominal material fractions within a unit volume at a given location computed using material distribution equations. The method is described thorough several case studies of abrupt transitions, lattice based transitions, and multi-material and structural transitions, including tolerances.
TOPICS: Additive manufacturing, Geometry, Functionally graded materials
research-article  
Ming Xu, James Yang, Isador Lieberman and Ram Haddas
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042326
Finite element analysis was used to investigate the responses of five adult degenerative scoliosis subjects to cyclic vibration before and after surgical alignment (SA). The dynamic responses of the healthy and pre-surgical scoliotic spines to the sinusoidal cyclic vibrations have been investigated in previous studies by computational and experimental approaches. However, no computational or experimental results were available for the pre- and post-surgical scoliosis subjects. The effect of the SA on the vibrational response of the post-surgical scoliosis subjects remained unknown. The objective of this study was to compare differences of the dynamic responses to the cyclic vibration input among the scoliotic spines for pre and post SA. Previous studies suggested that untreated scoliotic spines especially at the apical vertebrae are more sensitive to the vibration than spinal segments with normal anatomies. Results of this study showed that the SA was able to reduce the vibrational response of the scoliotic spines to the whole body vibrations at the fused level while not significantly increase the response at the superior adjacent level, which suggested that SA is able to reduce the risk of further degeneration in the scoliotic spines.
TOPICS: Finite element analysis, Surgery, Vibration, Scoliosis, Dynamic response, Risk, Experimental methods
research-article  
John-Travis Hansen and David Rosen
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042300
Product platforms allow companies to compete in the global marketplace by facilitating product variety and by adding, removing, or substituting components and features across a product family, while reducing costs and lead times. In many cases, developing a common platform involves determining which components are in a product family, their connections, and their spatial layouts. The development of product configurations and layouts is a complex problem and involves both discrete and continuous mathematical processes. This paper presents algorithms and an implementation to address the problem of configuring products and component layouts. The algorithms will describe the processes used to generate the product configurations based on constraints on combinations and the layout of components within the products. The implementation presents software developed to present the algorithms for the configuration and layout processes.
TOPICS: Algorithms, Design methodology, Computer software
research-article  
John Steuben, Andrew Birnbaum, Athanasios P. Iliopoulos and John Michopoulos
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042105
Additive Manufacturing (AM) enables the fabrication of objects using successive additions of mass and energy. In this paper we explore the use of analytic solutions to model the thermal aspects of AM, in an effort to achieve high computational performance and enable "in the loop" use for feedback control of AM processes. It is shown that the utility of existing analytical solutions is limited due to their underlying assumption of a homogeneous semi-infinite domain. These solutions must therefore be enriched from their exact form in order to capture the relevant thermal physics associated with AM processes. Such enrichments include the handling of strong nonlinear variations in material properties, finite non-convex solution domains, behavior of heat sources very near boundaries, and mass accretion coupled to the thermal problem. The enriched analytic solution method (EASM) is shown to produce results equivalent to those of numerical methods which require six orders of magnitude greater computational effort. It is also shown that the EASM's computational performance is sufficient to enable AM process feedback control.
TOPICS: Feedback, Additive manufacturing, Physics, Heat, Manufacturing, Materials properties, Numerical analysis
research-article  
Chih-Hsing Chu, Chih-Hung Cheng, Han-Sheng Wu and Chia-Chen Kuo
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042102
In this work, a cloud service framework is presented for the design evaluation of personalized footwear in augmented reality (AR) via networks. The service allows users to ubiquitously perceive themselves trying on 3D shoe models in a video stream. The users may upload a video clip of their feet in motion that has been recorded with a commercial depth camera to the cloud. A new clip is generated to display the try-on process and made available to specified receivers via video streaming on a mobile device. The proposed framework design is focused on making most use of open-source software and off-the-shelf technologies that are commercially available. A prototyping cloud system that implemented the framework demonstrated the practical value of virtual footwear try-on as AR as a Service (ARaaS). This research realizes the idea of human-centric design evaluation in modern e-commerce. The cloud framework may provide a feasible solution for the improvement of the usability for real-time applications of AR.
TOPICS: Design, Computer software, E-commerce
research-article  
Sungku Kang, Lalit Patil, Arvind Rangarajan, Abha Moitra, Dean Robinson, Tao Jia and Debasish Dutta
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042104
Manufacturing knowledge is maintained primarily in unstructured text in industry. To facilitate the reuse of the knowledge in unstructured text, previous efforts have utilized Natural Language Processing (NLP) to classify manufacturing documents or to extract manufacturing concepts and their hierarchies (e.g. ontology) from text. On the other hand, extracting more complex knowledge, such as formal manufacturing rules, has not been successful due to the lack of proper ambiguity resolution. Specifically, domain-specific ambiguities, that are due to manufacturing-specific meanings implicit in the English text, are not resolved by standard NLP techniques as they do not consider manufacturing domain context. To address the important gap, we developed the ambiguity resolution method that utilizes domain ontology as the mechanism to incorporate manufacturing domain context. We proved the feasibility of the method by extending the previously implemented formal manufacturing rule extraction framework. Specifically, the effectiveness of the method is demonstrated by resolving all the domain-specific ambiguities in the dataset, and an increasing the correct rules to 70% (increased by approx. 13%). We expect that the ambiguity resolution method will contribute to the adoption of semantics-based technology in manufacturing field, by enabling the extraction of precise formal knowledge from textual knowledge.
TOPICS: Manufacturing, Resolution (Optics), Ontologies, Ambiguity, Natural language processing, Semantics
research-article  
Edoh Goka, Lazhar Homri, Pierre Beaurepaire and Jean-Yves Dantan
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4042018
Tolerance analysis aims towards the verification impact of the individual tolerances on the assembly and functional requirements of a mechanism. The manufactured products have several types of contact and are inherent in imperfections, which often causes the failure of the assembly and its functioning. Tolerances are therefore allocated to each part of the mechanism in purpose to obtain an optimal quality of the final product. Three main issues are generally defined to realize the tolerance analysis of a mechanical assembly: the geometrical deviations modeling, the geometrical behavior modeling and the tolerance analysis techniques. In this paper, a method is proposed to realize the tolerance analysis of an over-constrained mechanical assembly with form defects by considering the contacts nature (fixed, sliding, and floating contacts) in its geometrical behavior modeling. Different optimization methods are used to study the different contact types. The overall statistical tolerance analysis of the over-constrained mechanical assembly is carried out by determining the assembly and the functionality probabilities based on optimization techniques combined with a Monte Carlo Simulation (MCS). An application to an over-constrained mechanical assembly is given at the end.
TOPICS: Tolerance analysis, Manufacturing, Modeling, Optimization, Failure, Probability, Simulation
research-article  
Mehdi Dehghani, Hamed Kharrati, Mirhadi Seyedarabi and Mahdi Baradarannia
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041969
The accumulated error as well as the noise sensitivity, are the two common problems of ordinary inertial sensors. An accurate gyroscope is too expensive which is not normally applicable in low-cost missions of mobile robots. Since the accelerometers are rather cheaper than similar types of gyroscopes, using redundant accelerometers could be considered as an alternative. This mechanism is called Gyroscope-free navigation. The article deals with Autonomous mobile robot navigation based on Gyroscope-free method. In this research, the navigation errors of the Gyroscope-free method in long-time missions are demonstrated. To compensate the position error, the aid information of low-cost stereo cameras and a topological map of the workspace are employed in the navigation system. After precise sensor calibration, an amendment algorithm is presented to fuse the measurement of GFIMU (Gyroscope-free inertial measurement unit) and stereo camera observations. The advantages and comparisons of vision aid navigation and Gyroscope-free navigation of mobile robots will be also discussed. The experimental results show increasing the accuracy in vision-aid navigation of mobile robot.
TOPICS: Navigation, Mobile robots, Errors, Sensors, Accelerometers, Noise (Sound), Algorithms, Calibration, Measurement units and standards
research-article  
Sif Edine Sadaoui, Charyar Mehdi-Souzani and C Lartigue
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041970
Computer-Aided Inspection Planning (CAIP) has gained significant research attention in the last years. So far, most CAIP systems have focused on the use of a touch probe mounted on a Coordinate Measuring Machine (CMM). This article investigates multi-sensor measurement aiming to perform automatic and efficient inspection plans. High level inspection planning, which deals with sequencing of measuring operations, is the main concern of inspection planning. This paper presents an automatic approach to generate inspection sequences by combining laser sensor and touch probe, and by giving preference to the measurement using the laser sensor if quality requirements are satisfied. The proposed approach consists of three steps. In the first step, recognition of inspection data from the CAD part model is carried out based on the concept of inspection feature, and the extracted information is stored in a database. In the second step, a list of privileged scanner orientations is proposed by analyzing the accessibility of both sensors. In the third step, a sequence of operations is generated iteratively. For a given scanner orientation, the ability of the laser sensor is assessed according to an original process based on fuzzy logic model. If the laser sensor does not meet the ability requirements, probe ability is assessed. The proposed approach is implemented and tested on a part defined by its CAD model and specifications
TOPICS: Sensors, Inspection, Computer-aided engineering, Lasers, Probes, Coordinate measuring machines, Computer-aided design, Databases, Preferences, Fuzzy logic
research-article  
Yuen-Shan Leung, Tsz Ho Kwok, Xiangjia Li, Yang Yang, Charlie C.L. Wang and Yong Chen
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041913
The revolution of additive manufacturing (AM) has led to many opportunities in fabricating complex and novel products. The increase of the printable materials and the emergence of the various fabricating processes continuously expand the capability of manufacturing. Our products are no longer limited to be single material, single scale or single function. In fact, a paradigm shift is taking place in the industries from geometry-centered usage to support functional demands, and hence it is expected to resolve wide range of complex and difficult problems. Although AM provides us higher design degree of freedom beyond the geometry to fabricate new objects with tailored properties and functions, there are only very few approaches for computational design in this new domain enabled by AM. The objectives of this study are to provide an overview on the current computer-aided design methodologies that are applied to multi-material, multi-scale, multi-form and multi-functional AM technologies. We summarize the difficulties encountered in the design approaches and emphasize the need for the future development. The study also introduces the related manufacturing processes, lists their present applications, and discusses their potential future trends.
TOPICS: Design, Computation, Additive manufacturing, Geometry, Manufacturing, Degrees of freedom, Computer-aided design
research-article  
Anthony P. Garland and Georges Fadel
J. Comput. Inf. Sci. Eng   doi: 10.1115/1.4041744
The goal of this research is to optimize an object's macroscopic topology and localized gradient material properties subject to multiple loading conditions simultaneously. The gradient material of each macroscopic cell is modeled as an orthotropic material where the elastic moduli in two local orthogonal directions we call x and y can change. Furthermore, the direction of the local coordinate system can be rotated to align with the loading conditions on each cell. This orthotropic material is similar to a fiber-reinforced material where the number of fibers in the local x and y-directions can change for each cell, and the directions can as well be rotated. Repeating cellular unit cells which form a mesostructure can also achieve these customized orthotropic material properties. Homogenization theory allows calculating the macroscopic averaged bulk properties of these cellular materials. By combining topology optimization with gradient material optimization and fiber orientation optimization, the proposed algorithm significantly decreases the objective, which is to minimize the strain energy of the object subject to multiple loading conditions. Additive manufacturing techniques enable the fabrication of these designs by selectively placing reinforcing fibers or by printing different mesostructures in each region of the design. This work shows a comparison of simple topology optimization, topology optimization with isotropic gradient materials, and topology optimization with orthotropic gradient materials. Finally, a trade-off experiment shows how different optimization parameters, which affect the range of gradient materials used in the design, have an impact on the final objective value of the design.
TOPICS: Design, Topology, Optimization, Fibers, Materials properties, Algorithms, Manufacturing, Elastic moduli, Printing, Additive manufacturing, Tradeoffs

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