bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Storing Mechanism for a New Hydraulic-Motor Actuated Robot
Authors: Chen Xianbao , Gao Feng , Qi Chenkun , Tian Xinghua , Zhang Jiaqi
Published: February 2014

A quadruped robot named “Baby Elephant” with parallel legs has been developed. It is about 1 m tall, 1.2 m long and 0.5m wide. It weighs about 130 kg. Driven by a new type of hydraulic actuating system, the Baby Elephant is designed to work as a mechanical carrier. It can carry a payload no less than 50 kg. Operating outdoors using wireless remote control, the robot will be able to traverse uneven terrain applying walking and trotting gaits and can walk up and down 10 degree inclines. The Baby Elephant carries a lithium battery fixed at the belly to supply all the power. This paper describes the structure of the legs and the application of the energy saving mechanisms on the leg. Simulations and experiments are carried out to testify the efficiency of the spring system in terms of energy saving.
Strategies for Consumer Control of Complex Product Forms in Generative Design Systems
Authors: Nordin Axel , Motte Damien , Bjärnemo Robert
Published: February 2014

In recent years, the number of products that can be tailored to consumers’ needs and desires has increased dramatically; there are many opportunities to individualize the colors, materials or options of products. However, current trends indicate that the future consumer will not be satisfied with mere material and color choices, but will desire control over form as well. While it is technically feasible to allow consumers to partially mass-customize the form of products subject to functional and production constraints through the use of a generative design system, the question of how the control of form should be presented to the user arises. The issue becomes especially important when the product form is based on complex morphologies, which require in-depth knowledge of their parameters to be able to control them fully. In this paper, we discuss this issue and present and test two strategies for controlling complex forms in consumer-oriented generative design systems, one offering the user full control over the design (“total control” strategy), while the other automatically generates designs for the user (“no control” strategy). The implementation of those two control strategies in a generative design system for two categories of products (bookshelf and table) and five types of morphologies are described and tested with a number of design interested participants to estimate their level of satisfaction with the two control strategies. The empirical study shows that the participants enjoyed both the total control and no control strategies. The development of the full control modes for the five morphologies was on the other hand not straightforward, and in general, making the controls meaningful to the consumer can be difficult with complex morphologies. It seems that a consumer-oriented generative design system with two different control strategies, as the ones presented in this article, would offer the most satisfaction.
Design and Implementation of a Data Acquisition Platform for Automated Mechanical Transmission (AMT)
Authors: Wang Lirong , Liu Kai
Published: February 2014

A kind of data acquisition platform to test vehicle shifting performance is presented based on virtual instrumentation technology. The platform helps to perform test efficiently by synchronously accessing various kinds of data transferred by electronic transducers and CAN bus, for example the signals of clutch travel, throttle angular, engine speed, gearbox input speed, vehicle velocity and acceleration and so on. A friendly GUI (Graphical user interface) is developed to manage experimental layout based on graphical function block in software of LabVIEW. QSM (Queued Stated Machine) to construct producer consumer architecture with functions of multi-channel and real-time data acquisition, data analysis and data storage is adopted. Vehicle experiment to acquisit data during shifting process of AMT (Automated Mechanical Transmission) are carried out, which takes advantages of high integration, great scalability and excellent reliability. The presented test platform is valuable to design and evaluation of electrical control system in vehicle.
High-Fidelity Modeling of a Backhoe Digging Operation Using an Explicit Multibody Dynamics Code With Integrated Discrete Particle Modeling Capability
Authors: Ahmadi Shahriar G. , Wasfy Tamer M. , Wasfy Hatem M. , Peters Jeanne M.
Published: February 2014

A high-fidelity multibody dynamics model for simulating a backhoe digging operation is presented. The backhoe components including: frame, manipulator, track, wheels and sprockets are modeled as rigid bodies. The soil is modeled using cubic shaped particles for simulating sand with appropriate inter-particle normal and frictional forces. A penalty technique is used to impose both joint and normal contact constraints (including track-wheels, track-terrain, bucket-particles and particles-particles contact). An asperity-based friction model is used to model joint and contact friction. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. A recursive bounding box contact search algorithm is used to allow fast contact detection between polygonal contact surfaces. The governing equations of motion are solved along with joint/constraint equations using a time-accurate explicit solution procedure. The model can help improve the performance of construction equipment by predicting the actuator and joint forces and the vehicle stability during digging for various vehicle design alternatives.
Wave Based Analysis of Buckling in Columns and Frames
Authors: Leamy Michael J.
Published: February 2014

This paper reports a wave-based analysis approach for predicting static buckling instabilities in axially-loaded columns and frames. It builds upon recent work on the wave-based vibration analysis of frame-like structures modeled by Timoshenko beams. To predict buckling, axial preload modeling is included in the equations of motion and the wave-based analysis approach is reformulated accordingly. This reformulation includes development of reflection and transmission matrices for a general, four-member angled joint. An eigenvalue problem (EVP) is then solved for example systems by setting the frequency of the wave solutions arbitrarily close to zero while seeking the axial preload which zeroes the EVP determinant. Numerical conditioning of the EVP problem is discussed as an essential step for ensuring successful application of the method. Notably, the method allows exact solutions to parameterized systems to be computed quickly and easily without the need for special discretization or mesh generation. This is exploited, for example, to find the optimal cross-brace location for an H-frame by varying a single parameter in the EVP determinant, avoiding the need to regenerate geometry and/or discretization (e.g., mesh topology). For a conservatively-loaded column, and for example portal and H-frames, results from the introduced approach show excellent agreement with known solutions.
RoGenSiD: A Rotary Plate Genderless Single-Sided Docking Mechanism for Modular Self-Reconfigurable Robots
Authors: Hossain S. G. M. , Nelson Carl A. , Dasgupta Prithviraj
Published: February 2014

Docking mechanisms are an integral part of modular self-reconfigurable robot (MSR) systems, allowing multiple robot modules to attach to each other. An MSR should be equipped with robust and efficient docking interfaces to ensure enhanced autonomy and self-reconfiguration ability. Genderless docking is a necessary criterion to maintain homogeneity of the robot modules. This also enables self-healing of a modular robot system in the case of a failed module. The mechanism needs to be compact and lightweight and at the same time have sufficient strength to transfer loads from other connected modules. RoGenSiD is a rotary-plate genderless single sided docking mechanism that was designed to perform robustly and efficiently considering its application in unstructured terrains. The design methodology followed design for manufacture (DFM) and design for assembly (DFA) guidelines as well as considerations for minimal space and weight. As a result, this docking mechanism is applicable for multi-faceted docking in lattice-type, chain-type, or hybrid MSR systems. Bench-top testing validated the system performance.
Dynamics of Globally-, Dissipatively-Coupled Resonators
Authors: Sabater Andrew B. , Rhoads Jeffrey F.
Published: February 2014

Examples of coupled resonator and oscillator arrays in engineering, scientific and mathematical contexts are diverse and abundant. However, when the technical scope is limited to mechanical systems, research typically focuses on arrays of resonators in which the coupling between the sub-units is conservative and nearest-neighbor in nature. In these arrays, if the sub-units are nominally identical, and the coupling is weak, collective behaviors such as localization, the spatial confinement of energy in distinct or limited regions, can be observed. In contrast, if the coupling is global and dissipative, very different collective dynamics are observed, namely, group resonance, confined attenuation, and group attenuation, the latter two of which are associated with the local absence of energy. This paper investigates these dynamic phenomena within the context of a generic, globally-, dissipatively-coupled system, which is motivated by recent work related to electromagnetically-coupled microresonator arrays. The results of this work have direct applicability in new single-input, single-output resonant mass sensors, and, with extension, a variety of other sensing and signal processing applications.
Deflection of an Eccentric Tooth of a Comb Drive in an Electrostatic Field
Authors: Meijaard J. P. , Krijnen B. , Brouwer D. M.
Published: February 2014

The elastic deflection of a comb drive tooth in an electrostatic field is considered. The tooth can be symmetrically located between two rigid teeth of the matching comb, in which case the problem reduces to a pure bifurcation problem for which the critical voltage can be determined. Alternatively, due to an approximate straight-line mechanism, the tooth can have a uniform initial lateral displacement and a smooth curve of equilibria is found which has a limit point, after which pull-in occurs.

An assumed deflection shape and a series expansion of the electrostatic capacity yield the deflection curves for the case with a uniform initial lateral displacement. This shows that pull-in occurs at a voltage that is reduced by a factor that is about proportional to the two-third power of the relative lateral initial displacement.

The theoretical results have been experimentally tested. The results show a qualitative agreement, but the experimental deflections are larger and the pull-in voltages are lower. These differences can be explained from neglected fringe fields and deviations from the nominal shape.
Time-Differentiable Null Space Method for Constrained Mechanical Systems (Application to a Rheonomic System)
Authors: Kamiya Keisuke
Published: February 2014

The governing equations of multibody systems are, in general, formulated in the form of differential algebraic equations (DAEs) involving the Lagrange multipliers. For efficient and accurate analysis, it is desirable to eliminate the Lagrange multipliers and dependent variables. Methods called null space method and Maggi’s method eliminate the Lagrange multipliers by using the null space matrix for the coefficient matrix which appears in the constraint equation in velocity level. In a previous report, the author presented a method to obtain a time differentiable null space matrix for scleronomic systems, whose constraint does not depend on time explicitly. In this report, the method is generalized to rheonomic systems, whose constraint depends on time explicitly. Finally, the presented method is applied to four-bar linkages.
Clustered Cell Parallelization for GPU Computing of Silicon Anisotropic Etching Simulation
Authors: Li Jianhua , Chen Jingyuan , Wang Yan , Huang Jianhua
Published: February 2014

The parallelization of silicon anisotropic etching simulation with the cellular automata (CA) model on graphics processing units (GPUs) is challenging, because the numbers of computational tasks in etching simulation dynamically change and the existing parallel CA mechanisms do not fit in GPU computation well. In this paper, an improved CA model, called clustered cell model, is proposed for GPU-based etching simulation. The model consists of clustered cells, each of which manages a scalable number of atoms. In this model, only the etching and update of states for the atoms on the etching surface and their unexposed neighbors are performed at each CA time step, whereas the clustered cells are reclassified in a longer time step. With this model, a crystal cell parallelization method is given, where clustered cells are allocated to threads on GPUs in the simulation. With the optimizations from the spatial and temporal aspects as well as a proper granularity, this method provides a faster process simulation. The proposed simulation method is implemented with the Compute Unified Device Architecture (CUDA) application programming interface. Several computational experiments are taken to analyze the efficiency of the method.
Four-Bar Linkage Synthesis for a Combination of Motion and Path-Point Generation
Authors: Tong Yuxuan , Myszka David H. , Murray Andrew P.
Published: February 2014

This paper develops techniques that address the design of planar four-bar linkages for tasks common to pick-and-place devices, used in assembly and manufacturing operations. Pick-and-place tasks often require the exact position and orientation of an object (motion generation) at the end points of the task. Within the range of movement, the motion restrictions are less rigorous with only the position of the object (path-point generation) being specified to avoid obstacles. Established synthesis theory has been developed for either motion generation or path-point generation tasks. This paper presents four-bar linkage synthesis methods for tasks that include a combination of motion and path requirements. This synthesis challenge is addressed via two approaches: Geometric Constraint Programming (GCP) and numerical solutions to synthesis equations. Using GCP, a step-by-step methodology has been established to find solutions to these synthesis challenges. Using numerical methods, techniques are presented to formulate kinematic chain constraint equations and solve for appropriate link lengths and pivot locations. Examples of various combinations of motion and path-point generation are presented.
Sequential Particle Swarm Optimization and Reliability Assessment of Planar-Type Voice Coil Motor
Authors: Wang Haikun , Huang Hong-Zhong , Xu Huanwei , Wang Zhonglai , Zhang Xiaoling
Published: February 2014

Planar-type voice coil motor (VCM) is a key component in ultra-precision motion of fine stage of lithography machine. The reliability-based design optimization (RBDO) method given in this work provides a novel criterion to ensure performance of Lorentz motors by evaluating the reliability of force constant. To solve the reliability based design optimization problem in discrete space with the speed of decoupled loop in sequential optimization and reliability assessment (SORA) for global solution, a Sequential Particle Swarm Optimization and Reliability Assessment method is proposed. The reliability boundary shift is put into penalty function for constrained optimization in fitness evaluation of particle swarm optimization (PSO). The presented optimization design model, the geometric parameters of the studied Planar-type VCM in finite element model are treated as design variables whereas the thrust force constant is an output quantity of interests. By using electromagnetic analysis, the desired requirements of Lorentz motors are verified.
A Model for the Representation of Surface Roughness and Form Deviation in Geometry Models
Authors: Weitzmann Oliver , Anderl Reiner
Published: February 2014

Functional integration and resource utilization are a challenge in today’s product development. The selective utilization of surface properties for functional integration offers potentials which aren’t exhausted until now. Surface roughness is mostly considered in manufacturing and measurement but the product properties impacted by surface roughness are determined in the product development. So it is necessary to integrate and extend the information about surface roughness in the methods and models of the product development. Therefore an approach for the representation of surface properties in product development is evolved. Based on the classification of surface deviation and profile courses, a method for building a surface profile is explored and depicted in an object-oriented representation model. One example for the functional integration and the use of technology-induced properties are sheet metal parts with higher order bifurcation in integral style. A new massive forming technology called linear flow splitting enables the manufacturing of sheet metal parts with higher order bifurcation in integral style. Within this manufacturing process, the material properties change heavily. Considering these changes in the product development, the representation model is needed to ensure the functionality. The model is used for generation a typical surface resulting from a linear flow splitting process.
Optimization of the Cutting Conditions for High Speed Drilling of Woven Composites
Authors: Meshreki Mouhab , Hamza Karim , Nassef Ashraf O. , Attia Helmi
Published: February 2014

The present work proposes a new algorithm for the optimization of cutting parameters in the high speed drilling of woven composites. The cutting parameters under consideration are the feed rate and the spindle speed. Three performance parameters are to be minimized. These are the exit delamination, the surface roughness and the thrust force. These performance parameters are observed experimentally. One of the challenges that face the experimental testing of these parameters is the high cost of the drilling tools and specimen materials. Therefore, the minimization of the number of experimental tests is a necessary requirement. The algorithm presented hybridizes Kriging as a meta-modeling technique with evolutionary multi-objective optimization to optimize the cutting parameters while intelligently selecting the new set of cutting parameters in each iteration. After starting with a factorial design of the search space, and after testing the performance criteria at these points, the algorithm fits a multi-dimensional surface using Kriging. This step is followed by an evolutionary search on the fitted model. The search spreads a population of search points in the direction of better performance criteria as well as in the direction of un-sampled space. The previous two steps are conducted iteratively for a pre-defined number of iterations. In the final iteration, the population of search points is clustered to yield a small number of new points at which the new experiments will be conducted. The whole process is iterated until the maximum number of allowable experiments is achieved. The algorithm is tested using an existing set of previously published experimental data that are dense enough to predict the actual response surface of the performance criteria. Results showed that the algorithm smartly moved into the direction of higher performance criteria with a low number of experimental trials.
A Concept of Camera Test-Bench for Testing Camera Based Advanced Driver Assistance Systems
Authors: Tan Yin , Hassan Bassem
Published: February 2014

About 1.5 million traffic accidents occur every year in European traffic; most of them are results of careless driving behavior, for example unintentional lane departure. Studies show that these accidents could often be avoided, if the driver would react only half a second earlier. Therefore, advanced driver assistance systems (ADAS) and especially the camera based ADAS increasingly gain importance in the automobile industry because of their diverse functions, for example the lane keeping assistance. Their development must contain an excessive and accurate testing process, in order to contribute to a reliable result in the common use. The importance of the testing methods and environments is growing due to several reasons, for example the need for more flexibility during testing and cost-reduction at the same time. Those requirements can be fully fulfilled by the use of virtual environments. To simplify the testing process, the virtual environment does not need to be as realistic as possible. It only has to provide necessary features for the camera system. Due to different detection algorithms for diverse assistance functions, the virtual environment needs determined characteristics, which are crucial for further precise analyses.

This paper presents a concept to create a camera test-bench for testing of camera based ADAS, by adapting an existing virtual environment for the camera system, identifying and enhancing the important features for the testing detection function while enable a flexible and low-cost testing environment. The testing ADAS shall record the virtual driving scenes and deliver the same results as in real environments.

First, possible existing approaches of testing processes shall be presented. In this paper, the concept is to shown by the example of road detection. The focus lies on the lane markings and the ground. While the separation lines between diverse objects are clearly visible in the virtual environment, the real ones often differ due to road condition or lighting intensity. The differences must be considered and corrected by creating a shader which adjusts the scenes, before the virtual representations can be applied for testing camera based ADAS. Furthermore, for testing other functions, the shader shall be expanded and contain more relevant feature parameters for different test functions. All in all, as much as possible camera based ADAS shall be tested with a virtual environment and the tests shall help accelerating the development time and improving the quality of camera based ADAS.
Soft Pneumatic Artificial Muscles With Low Threshold Pressures for a Cardiac Compression Device
Authors: Obiajulu Steven C. , Roche Ellen T. , Pigula Frank A. , Walsh Conor J.
Published: February 2014

In this paper, we present the design, fabrication and characterization of fully soft pneumatic artificial muscles (PAMs) with low threshold pressures that are intended for direct cardiac compression (DCC). McKibben type PAMs typically have a threshold pressure of at least 100 kPa and require rigid end fittings which may damage soft tissue and cause local stress concentrations, and thus failure points in the actuator. The actuator design we present is a variant on the McKibben PAM with the following key differences: the nylon mesh is embedded in the elastomeric tube, and closure of the end of the tube is achieved without rigid ends. The actuators were tested to investigate the effects of mesh geometry and elastomer material on force output, contraction, and rise time. Lower initial mean braid angles and softer elastomer materials provided the best force, contraction, and rise times; Up to 50 N of force, 24% contraction, and response times of 0.05 s were achieved at 100 kPa. The actuators exhibited low threshold pressures (<5 kPa) and high rupture pressures (138 kPa – 720 kPa) which suggest safe operation for the DCC application. These results demonstrate that the actuators can achieve forces, displacements, and rise times suitable to assist with cardiac function.
Nonlinear Vibration Behavior of Sandwich Beams With Entangled Fiber Core Material
Authors: Piollet Elsa , Michon Guilhem , Poquillon Dominique
Published: February 2014

In this paper, the use of entangled cross-linked fibers as core material in vibrating sandwich beams is investigated. The aim is to analyze the effect of this specific core material in terms of damping. The dynamic shear properties of the material are first studied experimentally. The shear modulus is shown to decrease with increasing shear strain amplitude at low shear strains. To include an amplitude dependency of the core material properties in the sandwich beam behavior, an analytical model is proposed. The equations of motion are derived using Lagrange’s equations. The shearing of the core is introduced in the equations through the use of virtual work to allow any relationship between shear stress and shear strain, including damping and nonlinearities. Experimental tests are carried out on sandwich beams with entangled fiber core material. The Frequency Response Function obtained exhibits decreasing resonant frequency and peak amplitude with increasing load amplitude. This softening behavior is consistent with the decreasing shear modulus. The proposed model is used take into account the softening nonlinearity. The FRF is reproduced with a linearly decreasing shear modulus and linearly increasing loss factor.
Surface Discontinuity Detection via Direct Strain Imaging
Authors: Iliopoulos Athanasios , Michopoulos John G.
Published: February 2014

Direct strain imaging is a recently developed full-field strain measurement method that accomplishes full field measurement of the strain tensor on the surface of a deforming body, by using arbitrarily oriented engineering strain measurements. This new approach doesn’t make any assumption on the compatibility of the strain field and thus it allows for consistent representation of media that may be or may not be discontinuous. In this paper, we present a novel method for detecting whether a discontinuity exists on a deformed body by evaluating the validity of the compatibility conditions over the imaging field. This approach can also be used for quantifying the shape and length of the discontinuity or crack. Synthetic numerical experiments based on the exact solution of a slant crack under biaxial loading were conducted to establish the detectability performance and the associated uncertainty of detection. Very encouraging results were derived indicating that for realistic levels of noise the method was found to be able to detect discontinuities as small as 0.3 mm long with very high confidence.
Dynamic Analysis of Automotive Hypoid Gears
Authors: Karagiannis I. , Theodossiades S.
Published: February 2014

The dynamics of differentials in rear wheel drive vehicles are of major importance for the automotive industry. Hypoid transmissions — forming the motion transfer mechanism from the driveshaft to the wheels — often suffer from severe vibrations, which could lead to Noise, Vibration and Harshness (NVH) issues. The latter are often attributed to improper mesh between the mating gear flanks due to misalignments, variation of contact load and shifting of the effective mesh position. A new modelling approach on the torsional dynamics of hypoid gear pairs is presented in this work. This is characterised by an alternative expression of the Dynamic Transmission Error (DTE), which accounts for the variation of the effective mesh position. Numerical results indicate the enriched dynamic behaviour that can be predicted using the new formulation. A solution continuation method is employed to follow the response branches over the operating range of the differential under examination. The ensuing parametric studies convey the importance of the main system parameters on the dynamic behaviour of the differential, yielding suggestions for design guidelines.
Performance Evaluation Model for Efficient Eco-Design Tool Integration
Authors: Goepp Virginie , Rose Bertrand , Caillaud Emmanuel
Published: February 2014

In the actual context, eco-design that focuses on the integration of environmental considerations into product development becomes a major stake for many companies. In order to make things happen, eco-design tools have to be made available for the product designers and for the working situations in product development processes. The research in the field proposes a lot of tools without dealing with their proper integration into a given design process. To succeed in requires evaluating their contribution to the eco-design process performance. Therefore, the objective of the paper is to propose a performance evaluation models. It is based on the analysis of general studies on design performance and the adaptation of the GAMETH® framework. The performance model proposed consists in evaluating the knowledge used and produced for each activity of a given design process, according to seven criteria related to time, cost, quality and contribution to the design objectives. A study case illustrates how the propositions made here can be applied.
A Simulation Based Estimation of Crowd Ability and its Influence on Crowdsourced Evaluation of Design Concepts
Authors: Burnap Alex , Ren Yi , Papalambros Panos Y. , Gonzalez Richard , Gerth Richard
Published: February 2014

Crowdsourced evaluation is a promising method for evaluating attributes of design concepts that require human input. One factor in obtaining good evaluations is the ratio of high-ability to low-ability participants within the crowd. In this paper we introduce a Bayesian network model capable of finding participants with high design evaluation ability, so that their evaluations may be weighted more than those of the rest of the crowd. The Bayesian network model also estimates a score of how well each design concept performs with respect to a design attribute without knowledge of the true scores. Monte Carlo simulation studies tested the quality of the estimations on a variety of crowds consisting of participants with different evaluation ability. Results suggest that the Bayesian network model estimates design attribute performance scores much closer to their true values than simply weighting the evaluations from all participants in the crowd equally. This finding holds true even when the group of high ability participants is a small percentage of the entire crowd.
Design for Availability (DFAV) and Design for Cost (DFC): Developing World Peculiarities
Authors: El-Khasawneh Bashar S.
Published: February 2014

The design process is driven by a number of requirements and constraints. In developing countries, designers are faced with extra constraints; such as the availability of components in the local market. The availability is not limited to procurement of part from local markets. It is extended to having parts within an acceptable quality. Developing world markets are flooded with a spectrum of varying quality products at different price ranges. Hence, it becomes the designer’s duty to identify the proper components that meets the functional requirements of the system. This paper covers the system/product development process; which is an extensive process, taking into account the reality of the local developing world markets. The paper starts by reviewing the literature on the design for X, and then shows how the design for availability and cost should be incorporated in the design process.
Guaranteed Manipulator Precision via Interval Analysis of Inverse Kinematics
Authors: Pac Muhammed R. , Rakotondrabe Micky , Khadraoui Sofiane , Popa Dan O. , Lutz Philippe
Published: February 2014

The paper presents a new methodology for solving the inverse problem of manipulator precision design. Such design problems are often encountered when the end-effector uncertainty bounds are given, but it is not clear how to allocate precision bounds on individual robot axes. The approach presented in this paper uses interval analysis as a tool for uncertainty modelling and computational analysis. In prior work, the exponential formulation of the forward kinematics map was extended to intervals. Here, we use this result as an inclusion function in the computation of solutions to set-valued inverse kinematic problems. Simulation results are presented in two case studies to illustrate how we can go from an uncertainty interval at the end-effector to a design domain of allowable uncertainties at individual joints and links. The proposed method can be used to determine the level of precision needed in the design of a manipulator such that a predefined end-effector precision can be guaranteed. Also, the approach is general as such it can be easily extended to any degree-of-freedom and kinematic configuration.
Modeling and Simulation of a Parametrically-Excited Micro-Mirror With Duty-Cycled Square-Wave Excitation
Authors: Shahid Wajiha , Qiu Zhen , Duan Xiyu , Li Haijun , Wang Thomas D. , Oldham Kenn R.
Published: February 2014

Electrostatically-actuated MEMS mirrors are used in a variety of applications involving fast optical scanning, with endoscopic microscopy an area of particular interest for miniaturization of advance optical imaging systems. In this paper, analytical and experimental characterization of the dynamics and stability of a 1D torsional micro-mirror is described. The micro-mirror being studied is intended for use in biomedical imaging, in which operation strictly by duty-cycled square waves at one or more voltages can be convenient for practical mirror operation and/or control. Analysis focuses on a Hill’s equation approach to predicting stability regions of parametric resonance behavior when input is a duty-cycled square wave, using an approximation for nonlinear capacitance behavior of the mirror. An analytical approach is compared to experimental results. In results to date, analytical models show good agreement with stability predictions, particularly at small voltages, over the range of duty cycled excitations. Additionally, the paper explores how phase delay varies over a range of micro-mirror frequencies for a 50% duty cycle, also compared with experimental results, for potential use in feedback control.
Optimal Design of the IRSBot-2 Based on an Optimized Test Trajectory
Authors: Germain Coralie , Caro Stéphane , Briot Sébastien , Wenger Philippe
Published: February 2014

This paper deals with the design optimization of the IRSBot-2 based on an optimized test trajectory for fast pick and place operations. The IRSBot-2 is a two degree-of-freedom translational parallel manipulator dedicated to fast and accurate pick-and-place operations.

First, an optimization problem is formulated to determine the optimal test trajectory. This problem aims at finding the path defined with s-curves and the time trajectory that minimize the cycle time while the maximum acceleration of the moving platform remains lower than 20 G and the time trajectory functions are C2 continuous.

Then, two design optimization problems are formulated to find the optimal design parameters of the IRSBot-2 based on the previous optimal test trajectory. These two problems are formulated so that they can be solved in cascade. The first problem aims to define the design parameters that affect the geometric and kinematic performances of the manipulator. The second problem is about the determination of the remaining parameters by considering elastostatic and dynamic performances.

Finally, the optimal design parameters are given and will be used for the realization of an industrial prototype of the IRSBot-2.
MEMS Based XY Stage With Large Displacement
Authors: Olfatnia Mohammad , Cui Leqing , Chopra Pankaj , Awtar Shorya
Published: February 2014

This paper presents a micro XY stage that employs electrostatic comb-drive actuators and achieves a bi-directional displacement range greater than 225 μm per motion axis. The proposed XY stage design comprises four rigid stages (ground, motion stage, and two intermediate stages) interconnected via flexure modules. The motion stage, which has two translational degrees of freedom, is connected to two independent single degree of freedom intermediate stages via respective parallelogram (P) transmission flexures. The intermediate stages are connected to the ground via respective Clamped paired Double Parallelogram (C-DP-DP) guidance flexures. The C-DP-DP flexure, unlike conventional flexures such as the paired Double Parallelogram flexure (DP-DP), provides high bearing direction stiffness (Kb) while maintaining low motion direction stiffness (Km) over a large range of motion direction displacement. This helps delay the onset of sideways instability in the comb-drive actuators that are integrated with the intermediate stages, thereby offering significantly greater actuation stroke compared to existing designs. The presented work includes closed-form stiffness analysis of the proposed micro XY stage, finite elements simulation, and experimental measurements of its static and dynamic behavior.
Optimisation of BPMN Business Models via Model Checking
Authors: Herbert Luke T. , Sharp Robin
Published: February 2014

We present a framework for the optimisation of business processes modelled in the business process modelling language BPMN, which builds upon earlier work, where we developed a model checking based method for the analysis of BPMN models. We define a structure for expressing optimisation goals for synthesized BPMN components, based on probabilistic computation tree logic and real-valued reward structures of the BPMN model, allowing for the specification of complex quantitative goals. We here present a simple algorithm, inspired by concepts from evolutionary algorithms, which iteratively generates candidate improved processes based on the fittest of the previous generation. The evaluation of the fitness of each candidate in a generation is performed via model checking, detailed in previous work. At each iteration, this allows the determination of the precise numerical evaluation of the performance of a candidate in terms of the specified goals. A discussion of this method’s application, and the degree of optimization which is possible, is illustrated using an example drawn from the healthcare industry.
The Calculation of the Degree of Parallelization of Documents and Risk Estimation in Product Development Processes
Authors: Schabacker Michael , Szélig Nikoletta , Vajna Sándor
Published: February 2014

In [1] different process modeling methods were evaluated and a tri-process modeling tool [2] was developed. After that it is often the case that the recorded product development processes have to be optimized in this tool. Previous studies of the authors have described the stages of process optimization in detail [3]. One of these stages was realized in [4] with the BAPM method. It has shown that there is no suitable method for the realization of the stage of process optimization called Simultaneous Engineering in the research literature.

The aim of this paper is to show one approach to realize Simultaneous Engineering by quantifying the degree of parallelization of documents. With the improved triangle it is possible to represent the relation between parallelization, resources and risk. This paper allows a quantified estimation of the change in the risk to be provided during the parallelization of the elements of a process.

Companies applying the optimization approaches discussed above will be able to perform more efficiently and create more efficient product development projects.
Explicit Force Control vs Impedance Control for Micromanipulation
Authors: Komati Bilal , Pac Muhammed R. , Ranatunga Isura , Clévy Cédric , Popa Dan O. , Lutz Philippe
Published: February 2014

This paper presents a study of different force control schemes for controlling contact during manipulation tasks at the microscale. Explicit force control and impedance control are compared in a contact transition scenario consisting of a compliant microforce sensor mounted on a microrobotic positioner, and a compliant microstructure fabricated using Silicon MEMS. A traditional double mass-spring-damper model of the overall robot is employed to develop the closed-loop force controllers. Specific differences between the two control schemes due to the microscale nature of contact are highlighted in this paper from the experimental results obtained. The limitations and tradeoffs of the two control laws at the microscale due to the presence of backlash are discussed. A simple method to deal with the pull-off force effects specific to the microscale is proposed. Future improvements of the impedance control schemes to include adaptation are discussed in order to handle objects with unknown stiffness.
Knowledge Management for Semi-Automated Automotive Assembly Instruction Authorship and Translation
Authors: Peterson Matthew , Mocko Gregory , Summers Joshua
Published: February 2014

The design and manufacture of large scale systems, particularly automobiles, is a process that requires collaboration across multiple disciplines. This collaboration is facilitated through efficient and effective data and knowledge storage and transfer. Specifically, the data associated with the final assembly of the vehicle should be generated, organized, and distributed in such a manner that each user of the data is able to use it effectively. Furthermore, the structure for the assembly data should be robust and reliable such that it fosters consistency among various planners for multiple vehicle platforms that are assembled all around the world. This research aims to develop a centralized data structure for assembly planning information that will allow a global automotive production company to create, relate, and store the necessary information for the assembly of multiple vehicle platforms in various locations, performed by associates that speak multiple languages. This is achieved by first observing the existing business processes of the company and identifying which processes are crucial to the production of vehicles, which processes may be omitted, and what processes need to be added. A data model is developed around these processes that allows multiple users to interact with the data as applicable to his or her duties, and a user interface is developed to demonstrate these interactions. The prototype system is demonstrated and tested.
Profiling Energy Consumption of Smartphone Users for Environmentally Efficient Business Decisions
Authors: Bernstein William Z. , Ramanujan Devarajan , Zhao Fu , Ramani Karthik
Published: February 2014

The recent proliferation of electronic products has led to a strong unmet need for understanding environmental implications of new technologies. According to Nielsen, 66% of Americans ages 24–35 own a smartphone, providing strong evidence that this technology can be considered ubiquitous. However, a majority of users and service providers are not sensitive to energy implications of data usage. As parameters affecting data delivery and usage are primarily driven by user behavior, this study is focused on using empirical data to investigate its correspondence to energy footprint. A large cohort of smartphone users (n = 21,853) and the means for which data is accessed, i.e. via 3G/LTE or WiFi, is examined to develop a model for estimating the energy cost of the various modes of data usage. Finally, alternate business scenarios are developed through simulating behavior change in cohorts based on existing data and then assessed with regards to economic and environmental efficiencies.
Defining the Phenomenon of Mental Models for Critical Events
Authors: van Deurzen Kanter , Horváth Imre , Vroom Regine
Published: February 2014

People use cognitive representations in order to characterize, understand, reason and predict the surrounding world. A class of these representations are called mental models. Designers of informing systems are interested in how mental models influence decision making, especially during critical events. With this knowledge they could optimize the content and amount of information that is needed for a dependable decision making process. New insights are needed about the operation of mental models in the course of critical events, as well as on how informing influences the real life operationalization of mental models. Most of the definitions available in the literature are overly general, and no definition was found that would support the design of informing systems for critical events. Therefore, the objective of our research was to derive a definition of mental models that play a role in critical events. Actually, we systematically constructed a definition from those attributes of mental model descriptions that were found to be relevant to critical events. First we decomposed 125 published descriptions to a set of attributes, and then assessed each attribute to see if they were associated with critical events, or not. In fact, this analysis involved not only the relevance of the attributes to critical events, but also the frequency of occurrence in the surveyed papers. This exploration provided a large number of attributes for a new mental model definition. Based on the top rated attributes, a definition was synthesized which, theoretically, has a strong relation to critical events. Though further validation will be needed, we argue that the derived mental model definition is strong because it establishes relationships with all generic features of critical events and makes the related information contents explicit. Hence the proposed definition can be considered a starting platform for investigations of the influence of informing on decision making processes in critical events.
Experiments of Sliding Mode Control of Time-Delayed Dynamical Systems With Model Uncertainty
Authors: Qin Zhi-Chang , Zhong Shun , Sun Jian-Qiao
Published: February 2014

This paper presents simulation and experimental results of sliding mode control of nonlinear mechanical systems with time delay in the control loop. A flexible link oscillator made by Quanser is used as the target system. Geometric nonlinearity of the spring is included in the model, and the system is assumed to have parameter uncertainties. A sliding mode control with time delay is designed with the method of continuous time approximation. Both computer simulations and experiments show that the sliding mode control gives quite robust performance in the presence of model uncertainty.
Microsurgical Devices by Pop-Up Book MEMS
Authors: Gafford Joshua B. , Kesner Samuel B. , Wood Robert J. , Walsh Conor J.
Published: February 2014

The small scale of microsurgery poses significant challenges for developing robust and dexterous tools to grip, cut, and join sub-millimeter structures such as vessels and nerves. The main limitation is that traditional manufacturing techniques are not optimized to create smart, articulating structures in the 0.1–10 mm scale. Pop-up book MEMS is a new fabrication technology that promises to overcome this challenge and enable the monolithic fabrication of complex, articulated structures with an extensive catalog of materials, embedded electrical components, and automated assembly with feature sizes down to 20 microns. In this paper, we demonstrate a proof-of-concept microsurgical gripper and evaluate its performance at the component and device level to characterize its strength and robustness. 1-DOF Flexible hinge joints that constrain motion and allow for out-of-plane actuation were found to resist torsional loads of 22.8±2.15 N·mm per mm of hinge width. Adhesive lap joints that join individual layers in the laminate structure demonstrated a shear strength of 26.8±0.53 N/mm2. The laminate structures were also shown to resist peel loads of 0.72±0.10 N/mm2. Various flexible hinge and adhesive lap components were then designed into an 11-layered structure which ‘pops up’ to realize an articulating microsurgical gripper that includes a cable-driven mechanism for gripping actuation and a flexural return spring to passively open the gripper. The gripper prototype, with final weight of 200 mg, overall footprint of 18 mm by 7.5 mm, and features as small as 200 microns, is able to deftly manipulate objects 100 times is own weight at the required scale, thus demonstrating its potential for use in microsurgery.