bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing Standards and Policies for Sustainability in Tolerance Optimization
Authors: Hoffenson Steven , Söderberg Rikard
Published: February 2014

Design for sustainability often considers three potentially competing objectives in economic, ecological, and social sustainability. In general, business success hinges on economic sustainability, while ecological and social concerns are treated as secondary objectives for marketing or political purposes. Previous research has shown that there is a tradeoff among these sustainability objectives regarding design decisions that include tolerances and material choices, and different market- or policy-driven incentives may result in different optimal design decisions. This study presents and demonstrates an approach for evaluating legislative opportunities that may internalize ecological and social objectives into the economic objectives of product-developing firms, using the case study of an automotive body panel. Modeling and simulation tools from Computer Aided Tolerancing (CAT), Life Cycle Assessment (LCA), and design optimization are combined using a novel framework to show how sustainability-driven government policies such as taxation may influence design decisions and sustainability outcomes.
Time-Optimal Trajectory Planning of Cable-Driven Parallel Mechanisms for Fully-Specified Paths With G1 Discontinuities
Authors: Barnett Eric , Gosselin Clément
Published: February 2014

Time-optimal trajectory planning (TOTP) is a well-studied problem in robotics and manufacturing, which involves the minimization of the time required for the operation point of a mechanism to follow a path, subject to a set of constraints. A TOTP technique, designed for fully-specified paths that include abrupt changes in direction, was previously introduced by the first author of this paper: an incremental approach called minimum-time trajectory shaping (MTTS) was used. In the current paper, MTTS is adapted for use with cable-driven parallel robots, which exhibit the additional constraint that all cable tensions remain positive along a path to be followed. For many applications, cable tensions along a path are verified after trajectory generation, rather than imposed during trajectory generation. For the technique proposed in this paper, the minimum-tension constraint is imposed directly and is fully integrated with MTTS, during trajectory generation, thus maintaining a time-optimal solution. This approach is relevant for cable-driven mechanism applications that involve high accelerations, particularly in the vertical direction.
A Simple Proof of the Existence of the Collinearity Circle for a Force-Input Coupler-Driven Four-Bar
Authors: Chang Yin-ping , Her Innchyn
Published: February 2014

This research investigates analytical analysis and synthesis problems of force-input and coupler-driven four-bar linkages. Very little bibliography can be found of this type of mechanism in contrast to the conventional torque-input crank-driven four-bars. Traditional four-bar mechanisms use the adjacent links jointed to the ground as input/output links; whereas a coupler-driven four-bar mechanism is actuated by applying the force or torque directly to the coupler link, the member has no direct connection to the base. In this paper, the transmission performance indices, TI (Transmissibility Index) and MI (Manipulability Index) are reviewed, Collinearity Points are defined, where both the MI and TI are unity and therefore the optimal motion transmission performance can be achieved. The Collinearity Circle, which is the locus of all Collinearity Points, is proposed, a novel performance indicator which is used to monitor the effectiveness of the transmission in a force-input coupler-driven four-bar. The beauty of this Collinearity Circle lies not only in its convenient shape, which is a circle, but also in its derivation that can be shown to be merely geometry-dependent. Just like the famous Instant Center, which is also only geometry-dependent, this new Collinearity Circle will prove to be a handy addition to the kinematics toolbox for its power to enable speedy construction and ballpark estimations on the transmission properties of force-input coupler-driven mechanisms. Observations and applications are presented.
Compact Model Synthesis for Partially Observed Operational Systems
Authors: Dion Jean-Luc , Abid Fatma , Chevallier Gaël , Festjens Hugo , Peyret Nicolas , Renaud Franck , Seifeddine Moustafa , Stephan Cyrille
Published: February 2014

This work proposes a Compact Model Synthesis (CMS) for Partially Observed Operational Systems (POOS) without using the complete knowledge of models. Series of “grey boxes” fed with partial observations are built in order to synthesize target variables with compact models. The recursive process for real time computation is based on Kalman Filters (KF). This stochastic approach allows to converge in line toward deterministic models with estimated uncertainties and without intrusion on the complete model process. Mathematical context is described first and illustrated secondly with two examples.
Preliminary Investigations Into the Design and Manufacturing of Fully Compliant Layered Mechanisms (FCLMs)
Authors: Mirth John A.
Published: February 2014

The relatively new technology of additive manufacturing (also known as “3-D printing” or “rapid prototyping”) presents some intriguing possibilities for the design of compliant mechanisms. This paper introduces a new category of compliant mechanisms — Fully Compliant Layered Mechanisms (FCLMs) — that rely on additive manufacturing to produce mechanisms with complex geometry. An FCLM is a fully compliant mechanism whose geometry requires two or more links to cross over one another to achieve a desired motion. The need to have crossing links requires the mechanism to have multiple layers. Such a mechanism is fairly easy to produce using additive manufacturing systems, but the more brittle materials associated with additive manufacturing also impose some limitations on the design of FCLMs. This paper presents an overview of some of these limitations along with approaches that are being developed to solve the challenges of using additive manufacturing in the production of compliant linkages. The focus is on lumped compliant mechanisms with key challenges that include: the selection of a proper joint type; the layering of the compliant mechanism; and the stability of the mechanism. Beam type joints such as a spiral joint are found to be suitable for use with additive manufacturing. These joints have some lateral instability which can be reduced by proper layering and structural reinforcements in the mechanism. These joints also pose the potential for increased parasitic motion, which can be minimized by joint design approaches. Preliminary ideas are presented for the solution of these problems along with some needs for future development.
Feedback Control of Periodic Delayed Systems
Authors: Nazari Morad , Bobrenkov Oleg A. , Butcher Eric A.
Published: February 2014

In this study, three control strategies based on Chebyshev spectral collocation and the Lyapunov-Floquet transformation (LFT) are explored for regulation control of linear periodic time delayed systems. In previous studies, control design based on Chebyhev spectral continuous time approximation (CSCTA) has been demonstrated for the delayed systems and the LFT has been utilized for the control of time-periodic non-delayed systems. However, the combined use of CSCTA and reduced LFT (RLFT) has thus far not been investigated for their application in control design for delayed periodic systems. The delayed Mathieu equation is used as an illustrative example, and the closed-loop response of the system and the control effort are investigated for all three control strategies.
Performance Improvement in Steering Torque Simulator With Multibody Vehicle Model
Authors: Takouda Toshimasa , Owaki Yoshinori , Tsushima Masashi , Shiiba Taichi
Published: February 2014

The aim of this study is to improve the performance of a steering torque simulator with a multibody vehicle model. From the perspective of the calculation speed, the augmented formulation and the penalty method were investigated as the formulation of the multibody dynamic analysis. In this study, the step size of the real-time analysis was shortened by embedding matrix libraries to the multibody dynamic analysis. In addition, the friction characteristics of the steering rack of an actual vehicle was experimentally evaluated in order to enhance the reality of the developed simulator. The friction model was identified on the basis of the experimental result and was applied to the multi-body dynamic analysis. A slalom test was conducted with the developed simulator and was compared with the experiment of an actual vehicle.
Thermal and Mechanical Responses of Particulate Composite Plates Under Direct Excitation
Authors: Miller Jacob K. , Rhoads Jeffrey F.
Published: February 2014

The thermal and mechanical near-resonant responses of particulate composite plates formed from hydroxyl-terminated polybutadiene (HTPB) binder and varying volume ratios of NH4CL crystals (50, 65, 75%) are investigated. Each plate is mounted and forced with three levels of band-limited, white noise excitation (10–1000 Hz at 1.00, 1.86 and 2.44 g RMS). The mechanical response of each plate is recorded via scanning laser Doppler vibrometry. The plates are then excited at a single resonant frequency and the thermal response is recorded via infrared thermography. Comparisons are made between the mechanical mode shapes of each plate and spatial temperature distributions, with correlation seen between stress/strain and heat generation. The effects of the various crystal/binder ratios on both the thermal and mechanical responses are discussed. Results are also compared to numerical simulations. The observed thermomechanical effects help render an improved understanding of the thermomechanics of plastic-bonded composites, an essential step in support of the development of new technologies for the vapor-based detection of hidden explosives.
Stiffness Matrix Evaluation for a Dual-Reeved Tensile Truss
Authors: Xiong Jerry , Hennessey Michael P.
Published: February 2014

Researchers have evaluated the stiffness matrix for different robots and structures, including the Stewart platform style tensile truss. However, none of the configurations analyzed to date involve “dual-reeving,” a common industrial rigging technique whereby cables are spatial loops, vs. open-loop elements, such as those represented by simple line segments. The 4-node/4-loop kinematic configuration analyzed contains 4 symmetric nodes and loops and provides competition for a comparable-sized Stewart platform from the perspective of directional stiffness. Additionally, like the Stewart platform, only a modest amount of off-diagonal compliance matrix elements are present, which from a practical and intuitive point of view, can be advantageous. The methodology used and illustrated in detail is easily generalized to adapt to more involved configurations. Numerical results are obtained for a specific example and compared with those from a Stewart platform. Lastly, some experimental results compare favorably with those derived analytically and evaluated numerically.
Implementation of SSM to Lateral Guided Steering Vehicle With Body Fixed High-Speed Camera
Authors: Takita Yoshihiro , Hisashi Date
Published: February 2014

This paper proposes an SSM (Sensor Steering Mechanism) for a lateral guided vehicle with an articulated body. Authors demonstrated a simple lateral guiding method SSM for front wheel steer type, the reverse phase four-wheel steer type and rear wheel steer type vehicles. SSM presents a stable lateral guiding performance for automated vehicle that following a straight and curved path created by a guideway. This paper proposes a simplified SSM to remove the following servo system for a rotating camera. The simplified SSM is applied to 1/25 scale articulated dump truck that was developed and discussed in the previous paper. The stability of the simplified SSM is discussed. Experimental and simulation results show stable movement and performance of the proposed method.
Optimization Algorithms and ODE’s in MDO
Authors: Bakker C. , Parks G. T. , Jarrett J. P.
Published: February 2014

There is a need for a stronger theoretical understanding of Multidisciplinary Design Optimization (MDO) within the field. Having developed a differential geometry framework in response to this need, we consider how standard optimization algorithms can be modeled using systems of ordinary differential equations (ODEs) while also reviewing optimization algorithms which have been derived from ODE solution methods. We then use some of the framework’s tools to show how our resultant systems of ODEs can be analyzed and their behaviour quantitatively evaluated. In doing so, we demonstrate the power and scope of our differential geometry framework, we provide new tools for analyzing MDO systems and their behaviour, and we suggest hitherto neglected optimization methods which may prove particularly useful within the MDO context.
Minimising Gear Losses
Authors: Stahl K. , Mayer Josef , Hinterstoißer Michael
Published: February 2014

The emissions of CO2 worldwide are actually an often discussed topic. To reduce these emissions, gear boxes offer several starting points. There are possibilities for loss reduction in gears, bearings and oil supply. Load dependent gear losses provide a big potential to improve efficiency at operating points with high load. At no-load, bearings, oil viscosity and oil supply can be optimized.

Aim of this study was the reduction of losses in power trains by about 30%. Main target of this project was the experimental investigation and verification of measures for loss reduction within one optimized gear box. Several approaches were combined for that.

Load-dependent gear losses can be reduced by about 60% by using lowloss gears. In this case, basic idea is to concentrate the gear contact around the pitch point for lower sliding speeds. Different surface topologies were investigated. These were manufactured by deterministic laser structuring, grinding or superfinishing. Especially for running conditions at low speed power loss reduction could be achieved by very smooth superfinished tooth flank surfaces. Reduction of power losses could also be reached by applying diamond like carbon (DLC) coatings. Loss savings by DLC coatings were measured especially at higher speeds with thick surface separating lubricant films. This is caused by a thermal isolation effect of coatings.
Characterization of Static Behavior of a Nonlinear Doubly Clamped Microbeam Under Electrostatic Actuation and Detection
Authors: Ahmadian Mohammad Taghi , Mojahedi Mahdi , Barari Ahmad , Firoozbakhsh Keikhosrow
Published: February 2014

In this study, the static deflection and pull-in instability of the doubly clamped microbeam with a mass attached to its midpoint are investigated. Nonlinear electrostatic forces, fringing fields, base rotation and mid-plane stretching of the beam in this model are considered. First, a system of two nonlinear integro-differential equations are expressed in partial derivatives which describe coupled flexural-flexural motion of electrostatically actuated microbeam gyroscopes under rotation. Then static deflection and pull-in instability of the microgyroscopes acted upon by DC voltages in both (direction and sensing) directions are studied. The equations of static motion are reduced by Galerkin’s decomposition method. The static response of the microgyroscope to variations in the DC voltage across the drive and sense electrodes is obtained.
Rotor-Stator Interaction Scenarios for the Centrifugal Compressor of a Helicopter Engine
Authors: Batailly Alain , Meingast Markus B. , Legrand Mathias , Ousty Jean-Philippe
Published: February 2014

The present paper deals with interaction phenomena that may arise in the centrifugal compressor of helicopter engines when structural contacts occur between the blade-tips and the surrounding casing. Those phenomena may lead to increased levels of vibration and are currently under investigation for axial compressors of aircraft engines for which blade failures were observed. The growing understanding of these phenomena allows for more challenging numerical simulations with increased geometrical complexity such as centrifugal compressors. The simulation of blade-tip/casing contacts is carried out based on an existing strategy previously introduced by the authors. An ovalized casing is considered and two contact configurations are investigated: (1) a single blade impacts the casing and (2) contact may occur on any blade of the cyclic assembly. Based on these two contact scenarios, an in-depth analysis is performed through both time and space Fourier transforms. Results highlight the plausibility of blade/casing interaction phenomena similar to those observed in axial compressors since interactions are detected with localized vibration levels on a single impacting blade. When contact is treated on all the blades of the centrifugal compressor, the witnessed interactions feature a higher degree of complexity and usual criteria become insufficient to predict interaction speeds as well as the location of significant peaks of vibration in the frequency domain.
Robust Optimization of Cylindrical Gear Tooth Surface Modifications Within Ranges of Torque and Misalignments
Authors: Artoni Alessio , Guiggiani Massimo , Kahraman Ahmet , Harianto Jonny
Published: February 2014

Tooth surface modifications are small, micron-level intentional deviations from perfect involute geometries of spur and helical gears. Such modifications are aimed at improving contact pressure distribution, while minimizing the motion transmission error to reduce noise excitations. In actual practice, optimal modification requirements vary with the operating torque level, misalignments, and manufacturing variance. However, most gear literature has been concerned with determining optimal flank form modifications at a single design point, represented by fixed, single load and misalignment values. A new approach to the design of tooth surface modifications is proposed to handle such conditions. The problem is formulated as a robust design optimization problem, and it is solved, in conjunction with an efficient gear contact solver (LDP), by a direct search, global optimization algorithm aimed at guaranteeing global optimality of the obtained micro-geometry solutions. Several tooth surface modifications can be used as micro-geometry design variables, including profile, lead, and bias modifications. Depending on the contact solver capabilities, multiple performance metrics can be considered. The proposed method includes the capability of simultaneously and robustly handling several conflicting design objectives. In the present paper, peak contact stress and loaded transmission error amplitude are used as objective functions (to be minimized). At the end, two example optimizations are presented to demonstrate the effectiveness of the proposed method.
Nonlinear Dynamic Response of an Electrically Actuated Imperfect Microbeam Resonator
Authors: Ruzziconi Laura , Bataineh Ahmad M. , Younis Mohammad I. , Cui Weili , Lenci Stefano
Published: February 2014

We present a study of the dynamic behavior of a MEMS device constituted of an imperfect clamped-clamped microbeam subjected to electrostatic and electrodynamic actuation. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. Extensive experimental investigation is conducted, where the main imperfections coming from microfabrication are detected and the nonlinear dynamics are explored at increasing values of electrodynamic excitation, in a neighborhood of the first symmetric resonance. The nonlinear behavior is highlighted, which includes ranges of multistability, where the non-resonant and the resonant branch coexist, and intervals where superharmonic resonances are clearly visible. Numerical simulations are performed. Initially, two single mode reduced-order models are considered. One is generated via the Galerkin technique, and the other one via the combined use of the Ritz method and the Padé approximation. Both of them are able to provide a satisfactory agreement with the experimental data. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Their computational efficiency is discussed in detail, since this is an essential aspect for systematic local and global simulations. Finally, the theoretical analysis is further improved and a two-degree-of-freedom reduced-order model is developed, which is capable also to capture the measured second symmetric superharmonic resonance. Despite the apparent simplicity, it is shown that all the proposed reduced-order models are able to describe the experimental complex nonlinear dynamics of the device accurately and properly, which validates the proposed theoretical approach.
Ontology-Enabled Data Inquiry for Cost Analysis and Obsolescence Mitigation
Authors: Chang Xiaomeng , Zheng Liyu , Terpenny Janis
Published: February 2014

Cost analysis is essential to enterprises developing plans to deal with product obsolescence. Indeed, cost analysis drives the optimization behind obsolescence mitigation planning and the maintenance of long field life sustainment-dominated systems. There are many different obsolescence mitigation solutions. Determining the optimum plan requires inputs from multiple departments within the enterprise such as maintenance, manufacturing, inventory, marketing, purchasing, etc. Moreover, proper analysis requires system records over a long period. As one might expect, these needs present challenges since proper data comes from different sources across multiple departments. In recent years, ontological models have been shown to be good at relation representation and knowledge management. Ontologies have been used to help with data integration and decision-making. This paper puts forward an ontology-based model and data inquiry method to help locate appropriate departments and related heterogeneous data for current and legacy data sources. The ontology-enabled data inquiry can then more accurately and efficiently improve cost analysis and the planning and management of obsolescence mitigation activities.
Methodology to Identify and Analyze Optimal Cable Configurations in the Design of Cable-Driven Serial Manipulators
Authors: Bryson Joshua T. , Agrawal Sunil K.
Published: February 2014

The choice of cable placement and routing for a cable-driven serial manipulator has profound effects on the operational workspace of the mechanism. Poor choices in cable attachment can hamper or preclude the ability of the mechanism to perform a desired task, while a clever configuration might allow for an expanded workspace and kinematic redundancies, providing additional capability and flexibility.

This paper outlines a methodology to identify and analyze optimal cable configurations for a serial manipulator which maximize operational workspace subject to mechanism design and configuration constraints. This process is first described in general terms for a generic 2-link robot and then applied to an illustrative example of a cable-driven robot leg. The methodology is used to determine the placement and routing of the cables to achieve the desired range of motion, as well as highlight the critical parameters within the cable configuration and identify possible areas of improvement in the overall robot design.
Experiments to Validate the Use of a Control Moment Gyroscope (CMG) to Turn Robots
Authors: Boddiford Andrew , Manion Charlie , Kim Kwan Suk , Radhakrishnan Pradeep , Sentis Luis
Published: February 2014

Turning a robot, particularly an under-actuated bipedal humanoid robot, is challenging. Several methods proposed in the literature for producing human-like motion in such robots are innovative but are limited in their range of motion. This paper presents an approach to control the orientation of a robot using a control moment gyroscope (CMG). A demonstration platform is developed to test this concept and physical experiments are conducted to determine the prototype’s turning range and performance. This concept is then extended to a backpack mount where trials are conducted using human subjects to estimate the performance of the system that can potentially be used to turn bipedal humanoid robots.
Training the Participatory Renaissance Man: Past Creative Experiences and Collaborative Design
Authors: Sauder Jonathan , Jin Yan
Published: February 2014

Students are frequently trained in a variety of methodologies to promote their creativity in the collaborative environment. Some of the training and methods work well, while others present challenges. A collaborative stimulation approach is taken to extend creative cognition to collaborative creativity, providing new insights into design methodologies and training. An experiment using retrospective protocol analysis, originally conducted to identify the various types of collaborative stimulation, revealed how diversity of past creative experiences correlates with collaborative stimulation. This finding aligns with previous research. Unfortunately, many current engineering design education programs do not adequately provide opportunities for diverse creative experiences. As this study and other research has found, there is a need to create courses in engineering design programs which encourage participation in diverse creative activities.
Comparison of Graph Generation Methods for Structural Complexity Based Assembly Time Estimation
Authors: Namouz Essam Z. , Summers Joshua D.
Published: February 2014

This paper compares two different methods of graph generation for input into the complexity connectivity method to estimate the assembly time of a product. The complexity connectivity method builds predictive models for assembly time based on twenty-nine complexity metrics applied to the product graphs. Previously the part connection graph was manually created, but recently the Assembly Mate Method and the Interference Detection Method have introduced new automated tools for creating the part connectivity graphs. These graph generation methods are compared on their ability to predict the assembly time of multiple products. For this research, eleven consumers products are used to train an artificial neural network and three products are reserved for testing. The results indicate that both the Assembly Mate Method and the Interference Detection Method can create connectivity graphs that predict the assembly time of a product to within 45% of the target time. The Interference Detection Method showed less variability than the Assembly Mate Method in the time estimations. The Assembly Mate Method is limited to only SolidWorks assembly files, while the Interference Detection Method is more flexible and can operate on different file formats including IGES, STEP, and Parasolid. Overall, both of the graph generation methods provide a suitable automated tool to form the connectivity graph, but the Interference Detection Method provides less variance in predicting the assembly time and is more flexible in terms of file types that can be used.
Systematic Development of Virtual Reality Convergence Support Tools Dedicated to Concurrent Product Design
Authors: Bennes Lionel , Bazzaro Florence , Sagot Jean-Claude
Published: February 2014

Concurrent and multidisciplinary product design processes are necessary to maintain the competitiveness of manufacturing industries, but their implementation is complicated by difficulties of collaboration between experts from different areas of expertise. Virtual reality can be used as an intermediate design representation in order to ease this collaboration. Nowadays, virtual reality is already in use in the industry for product design, but it suffers from acceptance issues by product designers. In this paper, we propose the As Soon As Possible methodology for the anthropocentric development of immersive multidisciplinary convergence support tools. These immersive tools can ease interdisciplinary collaboration while providing a response to the lack of virtual reality acceptance by designers. The feasibility of the concept is then demonstrated by an industrial use case.
An Innovative Approach to Design Education Across the Academic Pipeline: Technology Innovations for People With Disabilities
Authors: Goldberg Mary , Pearlman Jon , Mandala Mahender
Published: February 2014

This paper describes the model used by the Department of Rehabilitation Science and Technology (RST) at the University of Pittsburgh (Pitt) to teach the fundamentals of design using the development of assistive technology as the design objective. Our program, Technology Innovations for People with Disabilities (TIPeD), creates an ecosystem around design through the conceptualization, development, and commercialization of products. Through two classes, a fabrication lab (FabLab), and programs for both traditional (undergraduate and graduate students) and non-traditional (teachers and veterans) trainees, we facilitate experiential learning activities to convey design and product innovation principles. Undergraduate and graduate students progress through formal learning activities to be able to serve as mentors for our non-traditional trainees who are preparing for one of two pathways. Military veterans in our Experiential Learning for Veterans in Assistive Technology and Engineering (ELeVATE) program use our design and product innovation activities as a mechanism to get excited about and prepare for a transition in to formal education in engineering and technology. Teachers in our Research Experience for Teachers (RET) program use our activities as a mechanism to learn about engineering and design to create high school science and math curricular units to excite their students about science, technology, engineering, and math (STEM) careers. Though the purpose of this paper is to present and describe this program model, we chose to include both formative and summative evaluation procedures, in addition to preliminary results, to help demonstrate our efforts for continuous improvement of the program.
On the Stabilizability of the Delayed Inverted Pendulum Controlled by Finite Spectrum Assignment in Case of Parameter Uncertainties
Authors: Molnár Tamás G. , Insperger Tamás
Published: February 2014

An application of the Finite Spectrum Assignment (FSA) control technique is presented for an inverted pendulum with feedback delay. The FSA controller predicts the actual state of the system over the delay period using an internal model of the real system. If the internal model is perfectly accurate then the feedback delay can be compensated. However, slight parameter mismatch of the internal model may result in an unstable control process. In this paper, stabilizability of the inverted pendulum for different system and delay parameter mismatches are analyzed. It is shown that, for the same parameter uncertainties, the FSA controller allows stabilization for significantly larger feedback delays than a conventional delayed proportional-derivative controller does. In the analysis, it is assumed that the controller input is piecewise constant (sampled), this way the destabilizing effect of the difference part of the governing neutral functional differential equation is eliminated. The relation of the FSA controller to the Smith predictor is also described in time domain.
Smart Vision System for Shelf Analysis in Intelligent Retail Environments
Authors: Mancini Adriano , Frontoni Emanuele , Zingaretti Primo , Placidi Valerio
Published: February 2014

This paper aims to propose an innovative idea of an embedded intelligent, multimedia and interactive shop system where embedded vision systems can analyse human behaviours around shelves for interactivity and statistical purposes, mostly devoted to customer behaviour analysis, planogram maintenance and out of stock detection. We discuss the need for new services into the shop, involving consumers more directly and instigating them to increase their satisfaction and, as a consequence, their purchases. To do this, technology is very important and allows making interactions between costumers and products and between customers and the environment of the shop a rich source of marketing analysis. In particular we focus on concepts of monitoring and interactivity, introducing several emerging technologies in the field of retail environments. The main novelty of the paper is the general architecture of the system together with the introduction of a series of intelligent embedded systems, yet implemented and tested in a dataset recorded during the EuroShop trade fair, in cooperation with Grottini group, a leading company in Retail Design industry based in Italy. Results are convincing and most of all the general architecture is affordable in this specific application.
Superfinishing Rear Axle Gears: A Significant Step Toward Reducing Automotive Greenhouse Gas Emissions
Authors: Frechette Michael , Mershon Chris , Sroka Gary
Published: February 2014

New regulations make it imperative that the European and US automotive industries meet strict, lower greenhouse gas emission standards. It is well documented that isotropic superfinishing automotive rear axle gears can play a significant role in reducing these emissions. Rear axle gears have been commercially isotropic superfinished using conventional vibratory finishing for many years, but this process has often been viewed as being too expensive and cumbersome for large-scale automotive production. After five years of development and testing, the drag finishing process has been perfected to a point that rear axle gears can be isotropic superfinished economically in a matter of minutes. The gears are rapidly mounted and dismounted to the machine via magnetic fixturing making this equipment amenable to full robotic operation.

This paper will give details on the reduction of greenhouse gas emissions by isotropic superfinishing, the drag finishing machine, the magnetic fixture of the rear axle gears, the achievable surface finish, and the superfinishing cycle time.
Servo-Constraints for Control of Flexible Multibody Systems With Contact
Authors: Seifried Robert , Burkhardt Markus
Published: February 2014

This paper presents inversion based feedforward control design for flexible multibody systems with kinematic loops and end-effector contact. The inverse model provides for a given desired output trajectories, e.g. end-effector point and contact force, the required control inputs for exact output reproduction. A very appealing and efficient model inversion approach for such multibody systems is the use of so-called servo-constraints. These can be seen as an extension of classical mechanical constraints and yield a set of differential-algebraic equations. This allows an efficient numerical solution without burdensome symbolic manipulations. In addition, the use of servo-constraints allows the straight-forward treatment of flexible multibody systems with various topologies. The arising set of differential-algebraic equations describes the inverse model. The inverse model might be purely algebraic or include a dynamical part, which is called internal dynamics in nonlinear control theory. For its numerical solution it is advisable to transform the set of differential-algebraic equations to its underlying set of ordinary differential equations. The solution method for this internal dynamics depends then on its stability. For systems with unstable internal dynamics, as considered in this paper, a solution can be computed from a boundary-value problem. The efficiency of this approach is demonstrated for a flexible multibody system with a kinematic loop and a closed end-effector contact.
Accounting for Test Variability Through Sizing Local Domains in Sequential Design Optimization With Concurrent Calibration-Based Model Validation
Authors: Drignei Dorin , Mourelatos Zissimos P. , Pandey Vijitashwa , Kokkolaras Michael , Gorsich David
Published: February 2014

We have recently proposed a new method for combined design optimization and calibration-based validation using a sequential approach with variable-size local domains of the design space and statistical bootstrap techniques. Our work was motivated by the fact that model validation in the entire design space may be neither affordable nor necessary. The method proceeds iteratively by obtaining test data at a design point, constructing around it a local domain in which the model is considered valid, and optimizing the design within this local domain. Due to test variability, it is important to know how many tests are needed to size each local domain of the sequential optimization process. Conducting an unnecessarily large number of tests may be inefficient, while a small number of tests may be insufficient to achieve the desired validity level. In this paper, we introduce a technique to determine the number of tests required to account for their variability by sizing the local domains accordingly. The goal is to achieve a desired level of model validation in each domain using the correlation between model data at the center and any other point in the local domain. The proposed technique is illustrated by means of a piston design example.
Symmetry Design in Flexure Systems Using Kinematic Principles
Authors: Yu Jingjun , Li Shouzhong , Bi Shusheng , Zong Guanghua
Published: February 2014

Inspiration for the creation of mechanical devices often comes from observing the natural structures and movements of living organisms. Understanding the wide use of modularity and compliance in nature may lead to the design of high-performance flexure systems or compliant devices. One of the most important nature-inspired paradigms for constructing flexure systems is based on the effective use of symmetry. With a rigid mathematical foundation called screw theory and Lie group. The research of this paper mainly focuses on: (i) Mathematical explanation or treatment of symmetry design wildly used in flexure systems, concerning with a series of topics such as the relationship between degree of freedom (DOF), constraint, overconstraint, decouple motion and symmetrical geometry, and How to guarantee the mobility unchanged when using symmetry design? (ii) A compliance-based analytical verification for demonstrating that the symmetry design can effectively improve accuracy and dynamic performances. (iii) The feasibility of improving accuracy performance by connecting symmetry design with the principle of elastic averaging. The whole content is organized around a case study, i.e. symmetrical design of 1-DOF translational flexure mechanisms. The results are intent to provide a rigid theoretical foundation and significant instruction for the symmetry design philosophy in flexure systems using kinematic principles.
Small MR-Brake With Serpentine Flux Path and T-Rotor for Haptics
Authors: May Todd , Gurocak Hakan
Published: February 2014

In haptics applications, fast, stable and crisp force responses are desired. Magnetorheological (MR) brakes are used as actuators in haptics since they provide high torque-to-volume ratios. However, they still tend to be rather large and use high current inputs. We developed a new MR-brake with a T-rotor and serpentine flux path. The new device has 45 mm diameter and 65 mm length. It produces 6.5 Nm torque with 1A current input. It has more than double the torque-to-volume ratio of a commercial MR-brake and a previous T-rotor brake in literature. As such, it can open up many new application areas including portable systems. A prototype was built and tested to assess its effectiveness as a 1 degree-of-freedom (DOF) haptic device in virtual wall collision. The new MR-brake provided a crisp collision and release with the virtual wall.
Advanced Plate Theory for Multibody Dynamics
Authors: Bauchau Olivier A. , Han Shilei
Published: February 2014

In flexible multibody systems, many components are often approximated as plates. More often that not, classical plate theories, such as Kirchhoff or Reissner-Mindlin plate theory, form the basis of the analytical development for plate dynamics. The advantage of this approach is that it leads to a very simple kinematic representation of the problem: the plate’s normal material line is assumed to remain straight and its displacement field is fully defined by three displacement and two rotation components. While such approach is capable of capturing the kinetic energy of the system accurately, it cannot represent the strain energy adequately. For instance, it is well known from three-dimensional elasticity theory that the normal material line will warp under load for laminated composite plates, leading to a three-dimensional deformation state that generates a complex stress state. To overcome this problem, several high-order and refined plate theory were proposed. While these approaches work well for some cases, they typically lead to inefficient formulation because they introduce numerous additional variables. This paper presents a different approach to the problem, which is based on a finite element discretization of the normal material line, and relies of the Hamiltonian formalism of obtain solutions of the governing equations. Polynomial solutions, also known as central solutions, are obtained that propagate over the entire span of the plate.
Lateral Stable Workspace of Hexapod Walking Machines With Constant Orientation Platform
Authors: Qu Long , Agheli Mahdi , Nestinger Stephen S.
Published: February 2014

Due to the importance of the workspace and stability in mobile robot dynamic control, a variety of workspace and stability criteria exist in the field of multi-legged and wheeled robotics. This paper presents a methodology for determining the stable workspace, the subspace of the workspace for which the system is considered stable. The presented derivation utilizes the normal foot force distribution of the system to determine stability and integrates the stability into the lateral workspace of a mobile machining hexapod robot. The analytical inequalities governing the boundary of the stable workspace are derived. A discussion on the effects of physical and geometrical characteristics of the hexapod robot on the stable workspace methodology is given. The stable workspace methodology is validated through a simulation and an application to mobile machining is presented.
Driving Entrepreneurial Innovation Through the Learning Factory: The Power of Interdisciplinary Capstone Design Projects
Authors: Simpson Timothy W. , Kisenwether Elizabeth , Pierce Gregory R.
Published: February 2014

Founded in 1995, the mission of the Learning Factory at the Pennsylvania State University has been to integrate real-world, hands-on design/build experience into the engineering classroom through industry-sponsored capstone design projects. While the Learning Factory began like many other capstone design programs, a new college-wide capstone model emerged over the past five years to enable interdisciplinary design teams across multiple departments. First 3, then 4, 5, 8, and now 12 engineering majors regularly collaborate in what has become the largest industry-supported and college-wide capstone design program in the nation. Now more than 70% of the capstone design teams involve students from two or more disciplines, with some teams consisting of 4–5 different engineering majors. At the same time that we improved our ability to work across disciplinary boundaries, many entrepreneurs and start-up firms became aware of our capstone design program, and we found ourselves working with more and more of them on projects involving concept development and prototyping. In fact, the more interdisciplinary the program became, the better we could meet their needs, which often required input from 3 or more engineering disciplines as well as non-engineering disciplines. As a result, the number of capstone design projects sponsored by “real” entrepreneurs and start-ups has increased eight-fold over the past five years: from 5 projects in 2007/08 to over 40 projects in 2011/12. We discuss the factors that contributed to this growth, including industry-friendly intellectual property and non-disclosure agreements, a low-cost sponsorship model, a multidisciplinary capstone design section that satisfied the ABET requirements among all participating departments, and student interest in making a significant and immediate impact on their industry-sponsored project. The risks and challenges of working with start-ups and entrepreneurs is also discussed, namely, managing sponsor’s expectations, working with non-technical sponsors, clarifying project scope, avoiding project creep, and emphasizing the educational experience over project outcomes. Recent start-up successes are discussed along with a student entrepreneurial team’s capstone project prototype that lead to a successful fund-raising campaign on Kickstarter.
One Novel Isoconstrained Parallel Robot With Schoenflies-Motion
Authors: Lee Po-Chih
Published: February 2014

The coupling between two opposite bars of the hinged parallelogram produces relative 1-DoF circular translation and the opposite bars can move but remain parallel. From the point of view of kinematics, a hinged parallelogram is equivalent to a prismatic pair for a small motion. On the basis of a special parallel mechanism with the limb architecture of type CPUh (C and P denote cylindrical and prismatic pairs; Uh indicates the pseudo-universal-joint having one revolute and one screw pairs with the intersecting axes), we provide one novel Schoenflies-motion isoconstrained CPaUh//CPaUh robot with only two limbs having the hinged parallelograms for the fast pick-and-place operation of the assembly and packaging applications. This type of robot is compact for not only its structure but also its actuation. The robot architecture and kinematics including inverse and forward solutions are studied. In addition, Jacobian matrix, singularity analysis and workspace are further discussed. It is hoped that the evaluations of such two-limb parallel mechanism can be useful for possible application in industry where pick-and-place motion and higher accuracy are required.
Estimation of Bending Fatigue Life of Hypoid Gears Using a Multiaxial Fatigue Criterion
Authors: Hotait M. A. , Kahraman A.
Published: February 2014

In this study, a crack initiation life prediction methodology for the tooth bending fatigue of hypoid gears is proposed. This methodology employs a previously developed finite-element based hypoid gear root stress model [1] of face-milled and face-hobbed hypoid gears to establish the multiaxial stress time histories within the root fillet regions. These stress time histories are combined with a multiaxial crack initiation fatigue criterion to predict life distributions along roots of the pinion and the gear. The predictions of the multiaxial fatigue model are compared to those from a conventional uniaxial fatigue model to establish the necessity for a multiaxial approach. The model is exercised with an example face-milled hypoid gear set from an automotive application to demonstrate the impact of various misalignments as well as the key cutting tool parameters on the resultant tooth bending lives.