bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Test of Differential Planetary Gear System for Open Rotor Power Gearbox
Authors: Imai Hideyuki , Goi Tatsuhiko , Kijima Kenichi , Nishida Tooru , Arisawa Hidenori , Matsuoka Tetsuya , Sato Maiko
Published: February 2014

The open rotor engine is a next generation aero-engine that satisfies the demand for high fuel efficiency and low CO2 emission. A differential planetary gear system is incorporated in the open rotor engine to connect the turbine output shaft and fan rotors in order to counter-rotate the fan rotors as well as allow the turbine and fan rotors to operate at more efficient speeds. The open rotor gear system is required to have not only 20,000 hp high power transmission, but also an increasingly high efficiency, high reliability and light weight. To achieve these requirements, the following design works were conducted; (1) a low misalignment and lightweight carrier, (2) a flexible structure to absorb the displacement caused by the flight load, (3) an optimum gear tooth modification and (4) reduction of oil churning and windage losses. Also, extensive analyses and simulations such as lube oil flow CFD, FEA and tooth contact analysis were conducted. A full scale prototype gear system was manufactured and validation tests were conducted using a newly constructed test rig to validate the design concept. A slow roll test, rated performance test and efficiency test were conducted. And the design concept was found to be valid. This paper describes details of the prototype design and the results of the validation tests.
Optimal Motion Generation for Exiting a Parallel Manipulator From a Type 2 Singularity
Authors: Pagis Georges , Briot Sébastien , Bouton Nicolas , Martinet Philippe
Published: February 2014

Parallel robots have proved they can have better performances than serial ones in term of rigidity and payload-to-weight ratio. Nevertheless their workspace is largely reduced by the presence of singularities. In particular, the Type 2 singularities (parallel singularities) separate the workspace in different aspects, corresponding to one (or more) robot assembly modes. In order to enlarge the workspace size, it has been proved that a mechanism can cross the singularity loci by using an optimal motion planning. However, if the trajectory is not robust to modeling errors, the robot can stop in the singularity and stay blocked.

Therefore, the objective of this paper is to show new general procedure that allows the exit of a parallel manipulator from a Type 2 singularity. Two strategies are presented. The first one proposes the computation of an optimal trajectory that makes it possible for the robot to exit the singularity. This trajectory must respect a criterion that ensures the consistency of the robot dynamic model all along the singularity loci. The second trajectory consists in declutching one of the robot actuator in order to change the kinematic and dynamic behavior of the mechanism so that no singularity exists anymore. Theoretical works are illustrated, discussed and analysed through simulations achieved on a planar five-bar mechanism.
Generalized Component Mode Synthesis for the Spatial Motion of Flexible Bodies With Large Rotations About One Axis
Authors: Ziegler Pascal , Humer Alexander , Pechstein Astrid , Gerstmayr Johannes
Published: February 2014

By far the most common approach to describe flexible multi-body systems in industrial practice is the floating frame of reference formulation (FFRF) very often combined with the component mode synthesis (CMS) in order to reduce the number of flexible degrees of freedom. As a result of the relative formulation of the flexible deformation with respect to the reference frame, the mass matrix and the quadratic velocity vector are state-dependent, i.e. non-constant. This requires an evaluation of both the mass matrix and the quadratic velocity vector in every integration step, representing a considerable numerical cost. One way to avoid the state-dependency is to use an absolute formulation as proposed in [2], which was extended in [4] for the use of the same shape functions as used in the classical CMS approach. In this approach, referred to as generalized component mode synthesis (GCMS), the total absolute displacements are approximated directly. Consequently, the mass matrix is constant, there is no quadratic velocity vector and the stiffness matrix is a co-rotated constant matrix. However, it was shown that when using the same shape functions as in the classical CMS approach, nine times the number of degrees of freedom are necessary to describe the same deformation shapes as in the CMS. Even though the integration times of the CMS and GCMS are of the same order, as presented in [5], in technical systems the majority of components are constrained to motions with only one single large rotation. Therefore, in this work the GCMS is formulated for large rotations around a fixed spatial axis. This allows to reduce the number of necessary flexible shape functions to three times the number of CMS shape functions and, consequently, further increases numerical efficiency compared to the GCMS for arbitrary large rotations. A piston engine composed of three flexible bodies, two of which rotate, is used as a test example for the planar formulation. It is compared to the GCMS and a classical FFRF with CMS. The results agree very well, while the GCMS for planar rotations is about three times faster than the other formulations.
Long-Term Analysis of Affective Qualities That Change Over Time: A Case of Lotion Container Design Based on Visual and Tactile Attributes
Authors: Yanagisawa Hideyoshi , Takahashi Yuhma , Okuno Takashi , Suzuki Hideya , Tsuchiya Erika
Published: February 2014

An attractive product successfully attracts people when it is first introduced. More importantly, it maintains people’s interest throughout its lifetime. A product’s ability to maintain attractiveness is an important factor in the design of a long-life product. Yet, what specific product qualities provide this aspect of attractiveness and what specific design attributes affect quality. People perceive product quality by the use of different sensory modalities such as vision and touch. The dominance of a particular sensory modality and perception of product quality may change over time during product use. Two aspects are involved in this type of time-series change: (1) physical changes in the product (e.g. deterioration) and (2) users’ psychological changes during their experiences with a product. In this paper, we propose an experimental methodology that can be used to quantify the effects of design characteristics in relation to certain sensory modalities on users’ appraisals of product quality and on the customers’ beliefs during continued product use. The methodology analyzes changes in effects with respect to design parameters in relation to certain sensory modalities and in relation to two aspects of change. We applied the methodology to the design of a face lotion container. Qualities perceived by both vision and touch exerted significant effects on participants’ decisions to purchase a product and continue its use. We asked 30 female participants aged between twenty and thirty years to use a sample daily for one month. Participants were required to record their opinions of the samples (online assessment). On the first day, one week, and one month later, we invited participants to visit the laboratory. During those visits, they were asked to assess 24 samples that contained different visual designs, varied surface finishes, differing amounts of lotion, and different surface conditions (offline assessment). Based on these results, we demonstrated that the significance of design factors that participants perceived by different sensory modalities qualitatively and quantitatively changed over time. In this case study of lotion container design, we discovered that the potentially significant effect of a delicate surface finish that provided comfortable tactile sensations regardless of surface conditions on quality perception during long-term product use.
Calculation Method for Coupled Vibration Between Tooth Contact and Nonlinear Structural Components Under Running Conditions
Authors: Aoyama Takayuki , Suzuki Atsushi , Inagaki Mizuho , Hashimoto Naohide , Kawaminami Mitsuhiro , Maki Hiroki
Published: February 2014

The purpose of this study was to develop a numerical calculation method for gear system vibration, which changes depending on nonlinear structural components such as bearing clearance and spline contact. The numerical calculation method uses multibody dynamics simulation with the following features: a) the use of theoretical tooth shapes and stiffness to represent the tooth contact of gear pairs, b) the use of finite element models to express the gear system, including the nonlinear structural components causing the variation, c) consideration of the coupled vibration between the tooth contact and gear system. The numerical calculation method allowed the prediction of the variation tendency due to changes in some clearances and spline contacts.
A Spatial Grammar for the Computational Design Synthesis of Vise Jaws
Authors: Gmeiner Thomas , Shea Kristina
Published: February 2014

For the machining and assembly of mechanical parts, their secure fixation in a defined position is crucial. To achieve this task, flexible fixture devices (FFDs) are the industry standard for small and medium batch-sizes. Unlike dedicated fixtures, FFDs allow for the fixation of different part shapes, increasing their applicability and economic efficiency. Aiming to create a low-cost and autonomous FFD, a reconfigurable vise with adaptable jaws was developed. The jaws can be machined to a variety of shapes to securely hold prismatic and cylindrical parts. In this paper, a spatial grammar approach for the computational design synthesis of these customizable jaws is presented. Different sets of rules for the generation of 3D solid models of vise jaws based on the model of the workpiece to be held are developed and realized in a CAD environment. The approach is verified by generating jaw designs for example parts.
Is There an Optimal Choice of Configuration Space for Lie Group Integration Schemes Applied to Constrained MBS?
Authors: Müller Andreas , Terze Zdravko
Published: February 2014

Recently various numerical integration schemes have been proposed for numerically simulating the dynamics of constrained multibody systems (MBS) operating. These integration schemes operate directly on the MBS configuration space considered as a Lie group. For discrete spatial mechanical systems there are two Lie group that can be used as configuration space: SE(3) and SO(3) × ℝ3. Since the performance of the numerical integration scheme clearly depends on the underlying configuration space it is important to analyze the effect of using either variant. For constrained MBS a crucial aspect is the constraint satisfaction. In this paper the constraint violation observed for the two variants are investigated. It is concluded that the SE(3) formulation outperforms the SO(3) × ℝ3 formulation if the absolute motions of the rigid bodies, as part of a constrained MBS, belong to a motion subgroup. In all other cases both formulations are equivalent. In the latter cases the SO(3) × ℝ3 formulation should be used since the SE(3) formulation is numerically more complex, however.
An Explicit Level-Set Approach for Structural Topology Optimization
Authors: Hamza Karim , Aly Mohamed , Hegazi Hesham
Published: February 2014

Level-set approaches are a family of domain classification techniques that rely on defining a scalar level-set function (LSF), then carrying out the classification based on the value of the function relative to one or more thresholds. Most continuum topology optimization formulations are at heart, a classification problem of the design domain into structural materials and void. As such, level-set approaches are gaining acceptance and popularity in structural topology optimization. In conventional level set approaches, finding an optimum LSF involves solution of a Hamilton-Jacobi system of partial differential equations with a large number of degrees of freedom, which in turn, cannot be accomplished without gradients information of the objective being optimized. A new approach is proposed in this paper where design variables are defined as the explicit values of the LSF at knot points, then a Kriging model is used to interpolate the LSF values within the rest of the domain so that classification into material or void can be performed. Perceived advantages of the explicit level-set (ELS) approach include alleviating the need for gradients of objectives and constraints, while maintaining a reasonable number of design variables that is independent from the mesh size. A hybrid genetic algorithm (GA) is then used for solving the optimization problem(s). An example problem of a short cantilever is studied under various settings of the ELS parameters in order to infer the best practice recommendations for tuning the approach. Capabilities of the approach are then further demonstrated by exploring its performance on several test problems.
Green Profit Maximization Through Joint Pricing and Production Planning of New and Remanufactured Products
Authors: Kwak Minjung , Koritz Katherine , Kim Harrison M.
Published: February 2014

To achieve “green profit” in their business, manufacturers who produce both new and remanufactured products must optimize their pricing and production decisions simultaneously. They must determine the buy-back price and take-back quantity of end-of-life products as well as the selling prices and production quantities of new and remanufactured products. With an aim to assist in optimal pricing and production planning, this paper presents a mixed-integer programming model that optimizes the three prices (of buyback, new and remanufactured products) and the corresponding production plan simultaneously. The model considers the two conflicting objectives of maximizing economic profitability and maximizing environmental impact saving. The model helps address potential barriers to remanufacturing, which include limited economic, and/or environmental sustainability of remanufacturing, imbalance between the supply of end-of-life products and the market demand for remanufactured products, and cannibalization of the sales of new products. The developed model is illustrated with an example of engine water pump.
Continuous Preference Trend Mining for Optimal Product Design With Multiple Profit Cycles
Authors: Ma Jungmok , Kim Harrison M.
Published: February 2014

Product and design analytics is emerging as a promising area for the analysis of large-scale data and reflection of the extracted knowledge for the design of optimal system. The Continuous Preference Trend Mining (CPTM) algorithm and a framework that are proposed in this study address some fundamental challenges in the context of product and design analytics. The first contribution is the development of a new predictive trend mining technique that captures a hidden trend of customer purchase patterns from large accumulated transactional data. Different from traditional, static data mining algorithms, the CPTM does not assume the stationarity, and dynamically extract valuable knowledge of customers over time. By generating trend embedded future data, the CPTM algorithm not only shows higher prediction accuracy in comparison with static models, but also provide essential properties that could not be achieved with a previous proposed model: avoiding an over-fitting problem, identifying performance information of constructed model, and allowing a numeric prediction. The second contribution is a predictive design methodology in the early design stage. The framework enables engineering designers to optimize product design over multiple life cycles while reflecting customer preferences and technological obsolescence using the CPTM algorithm. For illustration, the developed framework is applied to an example of tablet PC design in leasing market and the result shows that the selection of optimal design is achieved over multiple life cycles.
Compliant Mechanisms for Robotic Ankles
Authors: Sugar Thomas G. , Holgate Matthew
Published: February 2014

We have developed a compliant robotic tendon mechanism for a robotic ankle. In this paper, we analyze the differences between a stiff and compliant robotic tendon versus a stiff and compliant slider crank mechanism. The compliant, slider-crank mechanism reduces peak forces and speed required by an actuator at the ankle.
Robust Design of Gears With Material and Load Uncertainties
Authors: Gautham B. P. , Gupta Prateek , Kulkarni Nagesh H. , Panchal Jitesh H. , Allen Janet K. , Mistree Farrokh
Published: February 2014

Traditionally gears are designed using design standards such as AGMA, ISO, etc. These design standards include a large number of “design factors” accounting for various uncertainties related to geometry, load and material uncertainties. As the knowledge about these uncertainties increases, it becomes possible to include them systematically in the gear design procedure, thereby reducing the number of empirical design factors. In this paper a method is proposed to eliminate two design factors (viz., factor of safety in contact and reliability factor) used in standard AGMA-based design procedures through the formal introduction of uncertainty in the magnitude of load and material properties. The proposed method is illustrated via the design of an automotive gear with a desired reliability, cost, and robustness. The solutions obtained are encouraging and in-line with the existing knowledge about gear design, and thus reinforces the possibility of schematically reducing the aforementioned design factors.
The Failure Tolerance of Mechatronic Software Systems to Random and Targeted Attacks
Authors: Kasthurirathna Dharshana , Dong Andy , Piraveenan Mahendrarajah , Tumer Irem Y.
Published: February 2014

This paper describes a complex networks approach to study the failure tolerance of mechatronic software systems under various types of hardware and/or software failures. We produce synthetic system architectures based on evidence of modular and hierarchical modular product architectures and known motifs for the interconnection of physical components to software. The system architectures are then subject to various forms of attack. The attacks simulate failure of critical hardware or software. Four types of attack are investigated: degree centrality, betweenness centrality, closeness centrality and random attack. Failure tolerance of the system is measured by a ‘robustness coefficient’, a topological ‘size’ metric of the connectedness of the attacked network. We find that the betweenness centrality attack results in the most significant reduction in the robustness coefficient, confirming betweenness centrality, rather than the number of connections (i.e. degree), as the most conservative metric of component importance. A counter-intuitive finding is that “designed” system architectures, including a bus, ring, and star architecture, are not significantly more failure-tolerant than interconnections with no prescribed architecture, that is, a random architecture. Our research provides a data-driven approach to engineer the architecture of mechatronic software systems for failure tolerance.
The Oscillatory Behavior of Doubly Clamped Microgyroscopes Under Electrostatic Actuation and Detection
Authors: Mojahedi Mahdi , Firoozbakhsh Keikhosrow , Ahmadian Mohammad Taghi
Published: February 2014

In MEMS gyroscopes, it is essential to use matched resonance frequencies of the drive and sense vibrational modes for improving the sensitivity. For this end, the natural frequencies can be tuned by voltages. In this study, a new model is utilized to determine the natural frequencies of the doubly clamped beam microgyroscope. In the model, nonlinear electrostatic forces, fringing fields and mid-plane stretching of the beam are considered. The system is actuated and sensed by electrostatic force and its natural frequencies and stiffness are detuned by DC voltages. The oscillatory problem of the gyroscope is analytically solved versus DC voltages for different design parameters.
Global Optimal Design of Nanomechanical Resonators
Authors: Koh Sung K. , Kim Yong Chul
Published: February 2014

Novel nanomechanical resonators with high mass sensitivities are designed in an optimal manner. We are concerned with a nanomechanical resonator with step changes in cross section and determine its geometry so as to maximize its mass sensitivity. Since the mass sensitivity is proportional to the fundamental frequency, we decide the geometric shape so as to maximize the fundamental frequency. In particular, we design a cantilever resonator with a single discontinuity in its cross sectional area. As the design space of this design problem is decided by the volume of the resonator, we synthesize it for various prescribed volume constraints. The fundamental frequency is estimated based on the Euler-Bernoulli beam theory. We discovered that there is a unique global optimal solution of this design problem that does not depend on the given volume constraints. The mass sensitivity of optimally designed cantilever resonators is 1.9193 times greater than that of conventional uniform beam type resonators that are designed for the same volume. Consequently, the mass sensitivity of a nanomechanical uniform resonator of constant volume can always be enhanced without regard to its global size by modifying its geometry following the optimal design proposed in this paper.
Granular Jamming With Hydraulic Control
Authors: Jiang Allen , Aste Tomaso , Dasgupta Prokar , Althoefer Kaspar , Nanayakkara Thrishantha
Published: February 2014

In the field of soft robotics, granular jamming is a newly adopted variable stiffness mechanism involving the use of vacuum pressure to control soft, particulate matter to become a unified, solid-like structure. However, granular jamming is conventionally controlled with air, which reduces the mobility of the robot. This is because the compressibility of air requires large vacuum pumps or chambers. Instead, we propose the use of an incompressible fluid, such as water, to control the stiffness of the mechanism. This paper presents comparative studies that shows that a hydraulic granular jammed joint using deaired water can both achieve the same stiffness level with just one twentieth of the volume extraction and maintain the same hysteresis level of an air-based system.
Orthogonal Complement-Based Divide and Conquer Algorithm: A Detailed Investigation of Its Performance
Authors: Khan Imad M. , Anderson Kurt S.
Published: February 2014

In this paper, we characterize the orthogonal complement-based divide-and-conquer (ODCA) [1] algorithm in terms of the constraint violation error growth rate and singularity handling capabilities. In addition, we present a new constraint stabilization method for the ODCA architecture. The proposed stabilization method is applicable to general multibody systems with arbitrary number of closed kinematic loops. We compare the performance of the ODCA with augmented [2] and reduction [3] methods. The results indicate that the performance of the ODCA falls between these two traditional techniques. Furthermore, using a numerical example, we demonstrate the effectiveness of the new stabilization scheme.
Divide-and-Conquer-Based Large Deformation Formulations for Multi-Flexible Body Systems
Authors: Khan Imad M. , Anderson Kurt S.
Published: February 2014

In the dynamic modeling and simulation of multi-flexible-body systems, large deformations and rotations has been a focus of keen interest. The reason is a wide variety of application area where highly elastic components play important role. Model complexity and high computational cost of simulations are the factors that contribute to the difficulty associated with these systems. As such, an efficient algorithm for modeling and simulation of systems undergoing large rotations and large deflections may be of great importance. We investigate the use of absolute nodal coordinate formulation (ANCF) for modeling articulated flexible bodies in a divide-and-conquer (DCA) framework. It is demonstrated that the equations of motion for individual finite elements or elastic bodies, as obtained by the ANCF, may be assembled and solved using a DCA type method. The current discussion is limited to planar problems but may easily be extended to spatial applications. Using numerical examples, we show that the present algorithm provides an efficient and robust method to model multibody systems employing highly elastic bodies.
Classification of Origami-Enabled Foldable Linkages and Emerging Applications
Authors: Zhang Ketao , Dai Jian S.
Published: February 2014

In the context of mechanisms, origami folds can be represented as equivalent mechanisms by taking creases as revolute joints and panels as links. This paper systematically presents various foldable closed-loop linkages extracted from origami folds and origami tessellations. The geometrical characteristics of typical origami crease patterns and patterned assemblies as well as the corresponding equivalent closed-loop linkage are investigated. The basic closed-loop linkages and complicated assemblies are classified according to their mobility in general configuration and the motion characteristics of these origami-enabled linkages are analyzed in terms of screw theory. Based on the geometry and motion analysis, possible simplified mechanisms of each complicated assembly are derived. The existing applications of the origami-inspired foldable closed-loop linkages in packaging and deployable structures, and emergence of new practical use in advanced robotics are addressed.
Coupled Tooth Contact Analysis of Intersected Beveloid Gears for Marine Transmissions
Authors: Zhu Caichao , Wang Haixia , Liu Mingyong , Du Xuesong , Song Chaosheng
Published: February 2014

Beveloid gears are widely applied in fields like ships, automobiles and industrial precision transmissions. In this paper, the formulas of the beveloid gear tooth surface used in marine transmissions were derived and a mesh model for the intersected beveloid gear pair was setup. Then loaded tooth contact analysis was performed using the finite element method considering the coupling of the assembly errors and the elastic deformation of tooth surface. Through the analysis, the influences of assembly errors on contact patterns, mesh force and tooth surface deformations were investigated. In a further step, the tooth profile modifications were performed to alleviate the edge contact and a subsequent major improvement of the mesh condition was obtained. Finally, loaded tooth contact experiments for marine gearboxes with small shaft angle were conducted. The tested results showed good correlation with the computed results. This work may provide some value for the practical design aiming at improved contact characteristics of the beveloid gears with intersected axes.
A Lengthwise Modification for Face-Hobbed Straight Bevel Gears
Authors: Shih Yi-Pei
Published: February 2014

Face hobbing has been successfully applying in manufacturing straight bevel gears using a virtual hypocycloidal straight-line mechanism. This method is a continuous indexing and double-flank cutting process, and is recognized its high productivity and precision. In order to improve gear contact condition, three types of flank modifications are frequently used in gear industry: profile crowning, lengthwise crowning, and longitudinal twist. In the design of the spiral bevel and hypoid gear, under satisfying a specified accuracy requirement, three types of modifications are blended properly during gear design to absorb assembly and manufacture errors. Circular cutter blades are normally adopted to accomplish the first type modification. The second can be achieved by a cutter radius change or a cutter tilt with adjusted pressure angles. The last can be achieved by a cutter tilt or modified tool path (for example, helical motion and modified roll). This paper proposes a lengthwise crowning method for face-hobbed straight bevel gear (SBG) using a hypocycloidal mechanism. This modification is applied to the pinion only. A numerical example drive with point-contact tooth surfaces is adopted to validate the proposed mathematical model. Finally, two evaluations, ease-off topography and tooth contact analysis (TCA), are made to investigate the contact condition of this numerical case.
Impactless Biped Walking on Stairs
Authors: Gong Lulu
Published: February 2014

A motion/force control scheme was proposed to investigate biped impactless walking, which has proven to be used effectively to achieve stable walking on slopes. This paper aims to investigate the efficiency of walking stairs. Good trajectory generation and effective control method are important for operating and ensuring the stability of biped walking on stairs.

Walking is illustrated by a seven-link biped with six control actuators, the number of which always equals to that of motion and force specifications. In order to avoid impacts, the specified motion of the biped and its ground reactions are controlled. Control torques, ground reaction forces and consumption energy of the biped lower limb joints are calculated for ascending stairs, walking on flat terrain and descending stairs. Three different locomotion velocities are studied in order to compare the energetic performance of the biped walking up-and-down stairs.
Sustained CAD Integration: A Proposed Method to Resolve Deficiencies Related to Data Export/Import
Authors: Kirkwood Robert , Sherwood James A.
Published: February 2014

Export/import based CAD integration is perceived by industry to be a second-rate integration. There have been various proposals to enhance such integration by refining and extending formats, generally via new formatting standards. The basic format for solid models has been stable for the last 20 years, so perhaps formatting standards are not the problem. In this paper, a different view of export/import issues for CAD models is proposed and evaluated using a rudimentary solid model where the export/import translation is perfect, but sustained integration still fails. The failure is found to be due to resequenced identifiers on the geometric entities, i.e. id-resequence. Various ways that id-resequence manifests itself in broken integration for subsequent versions of the solid model are explored in examples where the id-resequencing problem may remain hidden through the first few revisions before it “breaks” the integration. An explanation as to why integration via export/import is sometimes unavoidable is discussed.

Manually fixing the id-resequence enables sustained integration and solves most of the integration problems associated with export/import. Practical alternatives to manually fixing are assessed where one might repair or prevent the id-resequence problem, e.g. format/standard-extensions or application protocols, are explored and a proposed (recommended) new approach using virtual persistent identifiers is presented. This new approach offers a way to solve the id-resequence problem entirely from the import side. The approach also offers a way to repair/recover broken integration after the point where most might believe the damage has rendered the integration irreparable.

The results of an assessment for various proprietary CAD systems and also for STEP are evaluated. The evaluation shows that some applications are nearly ready to support sustained integration via export/import, while other applications require varying degrees of effort. The potential for virtual persistent identifiers to facilitate migration to STEP as the long-term solution for sustained integration is discussed.
Design and Robust Recognition of Omnidirectional Landmarks for Indoor Mobile Robot Positioning
Authors: Liu Hanyu , Zhong Xu , Zhou Yu
Published: February 2014

In this paper, we present an omnidirectional artificial landmark model and a robust artificial landmark recognition algorithm for indoor mobile robot positioning. The landmark model encodes identities with nested circles in black and white, which provides stable edge response and enables strong tolerance to various lighting conditions and perspective distortions. The corresponding positioning system uses a single upward-facing webcam as the vision sensor to capture landmarks. To address the effect of the lighting and sensing noise, the topological contour analysis is applied to detect landmarks, and the dynamic illumination adjustment is used to assist landmark recognition. Based on the landmark recognition, the absolute position of the camera in the environment is estimated using a trilateration algorithm. The landmark model and positioning system are tested with a mobile robot in a real indoor environment. The results show that the purposed technique provides autonomous indoor positioning for mobile robots with high robustness and consistency.
An Integrated Approach to Information Modeling for the Sustainable Design of Products
Authors: Eddy Douglas , Krishnamurty Sundar , Grosse Ian , Wileden Jack , Witherell Paul , Lewis Kemper
Published: February 2014

The design of more sustainable products can be best accomplished in a tradeoff-based design process that methodically handles conflicting objectives. Such conflicts are often seen between, environmental impact, cost, and product performance. To support such a process, we propose the development of an environment where sustainability considerations are explicitly introduced early into the design process. This explicitness is provided by integrating the requirements information of sustainability standards and regulations directly into the design process. The emergence of the semantic web provides an interoperable environment in which the context and meaning of knowledge about the relationships among various domains can be shared.

This work presents an ontological framework designed to represent both the objectives that pertain to sustainable design and the applicable sustainability standards and regulations. This integrated approach not only can ease the adoption of the standards and regulations during a design process but can also influence a design toward sustainability considerations. The usefulness of this model integration is demonstrated by an illustrative brake disk rotor and pads case study. The results show that both the standards and criteria may be considered at early design stages by using this methodology. Furthermore, it can be used to capture, reveal, and propagate the design intent transparently to all design participants.
An Activity-Based Costing Method to Support Market-Driven Top-Down Product Family Design
Authors: Coughlin Michael K. , Scott Michael J.
Published: February 2014

As more and more companies offer product families rather than individual products, the competitive advantage of product platforming is shrinking. In order to compete companies need to link marketing and engineering so that designers are able to make decisions about critical trade-offs between cost and performance. The current methods for market-driven platform designs use traditional product costing where indirect costs are assigned to individual products based on relative production quantities. Because of increasing product diversity and decreasing direct labor costs, the ratio of indirect costs to total cost of products is increasing. A method for use during the design stage of top-down product family design is needed to assign indirect costs to individual products based on the product’s consumption of indirect resources. An activity-based costing method for top-down product family design is presented here. This method allows the designer to model indirect costs as a function of engineering attributes, creating a framework for top-down product platform optimization that provides a more accurate estimation of cost than traditional product costing methods. An illustrative example shows that an activity-based costing model predicts different profitability from a traditional costing system for a number of different motor designs.
Comparison of Sustainability Performance for Cross Laminated Timber and Concrete
Authors: Piacenza Joseph R. , Tumer Irem Y. , Seyedmahmoudi S. H. , Haapala Karl R. , Hoyle Christopher
Published: February 2014

As sustainable building design practices become more prevalent in today’s construction market, designers are looking to alternative materials for novel design strategies. This paper presents a case study comparing the sustainability performance of cross laminated timber (CLT) and reinforced concrete. A comparative sustainability assessment of cross laminated timber and concrete, considering economic, environmental, and social aspects was performed. Environmental impact is measured in terms of CO2 equivalent, economic impact is measured with total sector cost (including sector interdependencies), and qualitative metrics were considered for social impact. In order to conduct an accurate performance comparison, a functional unit of building facade volume was chosen for each product. For this paper, several end-of-life strategies were modeled for CLT and concrete facades. To understand environmental, economic, and social impact, three different scenarios were analyzed to compare performance of both CLT and concrete, including cradle to gate product manufacturing, manufacturing with landfill end-of-life, and manufacturing with recycling end-of-life. Environmental LCA was modeled using GaBi 5.0 Education Edition, which includes its own database for elements including materials, processes, and transportation. To compare the economic impact, Carnegie Mellon’s EIO-LCA online tool is used. Finally, social life cycle impact was considered by identifying process attributes of both products that affect the social domain. Based on this analysis, the use of CLT has a significantly lower environmental impact than concrete, however there are additional costs.
DTM at 25: Essays on Themes and Future Directions
Authors: Braha Dan , Brown David C. , Chakrabarti Amaresh , Dong Andy , Fadel Georges , Maier Jonathan R. A. , Seering Warren , Ullman David G. , Wood Kristin
Published: February 2014

This paper describes the development and evolution of research themes in the Design Theory and Methodology (DTM) conference. Essays containing reflections on the history of DTM, supported by an analysis of session titles and papers winning the “best paper award”, describe the development of the research themes. A second set of essays describes the evolution of several key research themes. Two broad trends in research themes are evident, with a third one emerging. The topics of the papers in the first decade or so reflect an underlying aim to apply artificial intelligence toward developing systems that could ‘design’. To do so required understanding how human designers behave, formalizing design processes so that they could be computed, and formalizing representations of design knowledge. The themes in the first DTM conference and the recollections of the DTM founders reflect this underlying aim. The second decade of DTM saw the emergence of product development as an underlying concern and included a growth in a systems view of design. More recently, there appears to be a trend toward design-led innovation, which entails both executing the design process more efficiently and understanding the characteristics of market-leading designs so as to produce engineered products and systems of exceptional levels of quality and customer satisfaction.
Vibro-Acoustic Analysis of a Simple Gear Box
Authors: Park Chan Il , Rong Linguo
Published: February 2014

Mesh forces of helical gears produce forces and moments in bearings, which generate the housing vibration, and noise radiates. It is difficult to know the noise contribution of a gear box, because the gear box usually has very complex geometry. This work used a cylindrical shell-type gear box with end circular plates to understand the noise and vibration characteristics of a simple gear box and investigated the noise and the vibration of the helical gear box due to the force excitation. The helical gear box of this study consisted of a pairs of helical gears, shafts, bearings, and a gear box. Finite element analysis for the helical gear box calculated mode shapes and natural frequencies and the forced harmonic response by the commercial software. The models were validated by the impact test. Using the forced harmonic response, acoustic analysis was conducted by the commercial software and relations on vibration and noise were discussed.
Multi-Objective Robust Optimization Using Differential Evolution and Sequential Quadratic Programming
Authors: Cheng Shuo , Li Mian
Published: February 2014

Multi-Objective Robust Optimization (MORO) can find Pareto solutions to multi-objective engineering problems while keeping the variation of the solutions being within an acceptable range when parameters vary. While the literature reports on many techniques in MORO, few papers focus on the implementation of Multi-Objective Differential Evolution (MODE) for robust optimization and the performance improvement of solutions. In this paper, MODE is first modified and implemented for robust optimization, formulating a new MODE-RO algorithm. To improve the solutions’ quality of MODE-RO, a new hybrid MODE-SQP-RO algorithm is further proposed, where Sequential Quadratic Programming (SQP) is incorporated to enhance the local search. In the hybrid algorithm, two criteria, indicating the convergence speed of MODE-RO and the switch between MODE and SQP are proposed respectively. One numerical and one engineering examples are tested to demonstrate the applicability and performance of the proposed algorithms. The results show that MODE-RO is effective in solving Multi-Objective Robust Optimization problems; while on the average, MODE-SQP-RO significantly improves the quality of robust solutions with comparable numbers of function evaluations.
A Comparison of Design Approaches to Meso-Structure Development
Authors: Fazelpour Mohammad , Summers Joshua D.
Published: February 2014

The design protocols of meso-structures to satisfy given properties have been an interesting area in material science. Having various mechanical properties by modifying the topology of unit cells is a major issue in developing new meso-structures. This paper reviews different design methodologies to design meso-structures. For each method, an algorithm is presented and compared. Computational methods including topology optimization, parametric optimization, and synthesis methods are among the most popular methods for design meso-structures. Ultimately, it is found that there is a gap in systematic design methods for developing new meso-structure architectures as the current methods are limited to parametric sizing and selection. This gap will be addressed in future research.
Experimental Studies on Traction Concepts: Endurance and Obstacle Testing
Authors: McDougald Morgan A. , Mims Nelson S. , Moylan Justin T. , O’Shields Steven T. , Satterfield Zachary T. , Smentek Brett T. , Summers Joshua D.
Published: February 2014

This paper presents experimental endurance results of three undergraduate-designed and built soft soil traction concepts. An experimental approach was chosen due to the limitations of current analytical models of traction on soft soils. The use of analytical models requires detailed understanding of the geometry and mechanics of the tread not readily available. Experimental methods do not require this advanced understanding and provide rapid and realistic results. Building on previous research which showed that the use of high density foam and concave geometry increased the traction performance of a tire in sand, three new concepts are prototyped with a focus on exploring endurance and survivability in aggressive testing. These prototypes employed the use of thinner foam than was previously studied, bed liner, and a combination of Kevlar and bed liner (“Kevliner”). The prototypes were tested in a rotating trough filled with sand where each tread prototype was subjected to distance and acceleration tests with and without a rock obstacle. The damage incurred by the prototype and the percentage of slip between the tire and the trough was recorded during each test to assess the performance of each prototype. Analysis of the slip data collected showed that there was little variation in traction between the three prototypes. This was expected as each concept was based on similar working principles for traction. Therefore, more significance was placed on the physical damage sustained by the prototype to evaluate performance than the slip. The Kevliner prototype proved to be the highest performing prototype. It was the only prototype to complete the entire testing suite. The thin foam and bed liner prototypes both sustained severe damage during an acceleration test with the rock obstacle (the fifth of the six tests). The success of the Kevliner prototype can be attributed to the added strength and durability provided by the Kevlar.
HOTINT: A Script Language Based Framework for the Simulation of Multibody Dynamics Systems
Authors: Gerstmayr Johannes , Dorninger Alexander , Eder Rafael , Gruber Peter , Reischl Daniel , Saxinger Martin , Schörgenhumer Markus , Humer Alexander , Nachbagauer Karin , Pechstein Astrid , Vetyukov Yury
Published: February 2014

The multibody dynamics and finite element simulation code has been developed since 1997. In the past years, more than 10 researchers have contributed to certain parts of HOTINT, such as solver, graphical user interface, element library, joint library, finite element functionality and port blocks. Currently, a script-language based version of HOTINT is freely available for download, intended for research, education and industrial applications. The main features of the current available version include objects like point mass, rigid bodies, complex point-based joints, classical mechanical joints, flexible (nonlinear) beams, port-blocks for mechatronics applications and many other features such as loads, sensors and graphical objects. HOTINT includes a 3D graphical visualization showing the results immediately during simulation, which helps to reduce modelling errors. In the present paper, we show the current state and the structure of the code. Examples should demonstrate the easiness of use of HOTINT.
Type Synthesis of 2-DOF Rotational Parallel Manipulators With an Equal-Diameter Spherical Pure Rolling Motion
Authors: Wu Kang , Yu Jingjun , Zong Guanghua , Kong Xianwen
Published: February 2014

Two-degree-of-freedom (2-DOF) rotational parallel manipulators (RPMs) have been widely used in pointing devices and robot wrists. This paper focuses on a class of 2-DOF RPMs achieving an equal-diameter spherical pure rolling motion (ESPRM) around the base. At first, a theoretical model of spherical pure rolling motion is analyzed and the characteristic of the associated constraint space is derived. Taking the Omni-Wrist III as a typical 2-DOF RPMs with an equal-diameter spherical pure rolling motion, mappings between the geometry and the motion are established and eight useful constraint conditions are derived which will be instructive for the type synthesis. Then, with focus on symmetrical structures, nine classes of 2-DOF RPMs with equal-diameter spherical pure rolling motion are synthesized based on the graphic method. Most of these RPMs have already been used in practice. Unlike the conventional type synthesis of lower-mobility parallel manipulators in literatures, some geometrical parameters of links, in addition to the distributions of joints and limbs, are taken into consideration in the type synthesis in this paper. This proposed research may help produce novel architectures.