bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-Linear Dynamics of Microcantilevers in Liquid Environment Atomic Force Microscopy When Operating at the Second Eigenmode: Subharmonics, Multiple Impacts, and Chaos
Authors: Kiracofe Daniel R. , Raman Arvind
Published: March 2011

Many newer atomic force microscopy (AFM) methods aim to excite higher-order eigenmodes of the microcantilevers in multi-frequency excitation/detection schemes for improving compositional contrast in nanoscale imaging. Yet, before moving to multi-mode excitation schemes it is important to understand how, if at all, operating the microscope at eigenmodes beyond the fundamental is different from operating at the fundamental eigenmode. This question becomes particularly relevant for biological applications when cantilevers are operated in liquid environments, which is critical for studying biological processes under physiological “native” conditions. In this work, the dynamics of AFM cantilevers in liquids are investigated when the cantilever is driven at its second natural frequency — a situation, which from prior work in air or vacuum, ought not be essentially different from operating at the first natural frequency. The dynamics of cantilevers in liquids tapping on samples are in fact found to be surprisingly different when operating at the second eigenmode. A complex set of behaviors are found including sub-harmonic (e.g. only one impact every four drive cycles), drum-roll like multiple-impacts (e.g.two or three impacts every drive cycle) and chaotic. The subharmonic behaviors, in particular, have not been studied before in liquids and are not accounted for in any current method. These behaviors are demonstrated through numerical simulations and confirmed with experiments.
Optimum Design of an Anchoring System for Percutaneous Mitral Valve Repair
Authors: Javid Farhad , Angeles Jorge , Pasini Damiano , Cecere Renzo
Published: March 2011

In a novel procedure for percutaneous mitral valve repair, inter-related hook-shaped anchors are inserted around the annulus to replace the surgeon’s suturing in open-heart ring annuloplasty. To properly attach to the tissue, the anchors should withstand large deformation applied during the delivery process and recover their original shape when released into the heart tissue. To this end, stress concentration is avoided along the anchors, which are fabricated of a super-elastic material, by means of shape optimization. Shape optimization consists in finding the smoothest anchor mid-curve possible, which minimizes the von Mises stresses applied during the delivery process. An optimization algorithm aimed at minimizing the weighted rms value of the curvature is introduced. A geometrically optimum shape is obtained by equally weighting the curvature values. Further reduction in the stress values is possible by weighting the curvature values along the anchor in an iterative procedure that yields a structurally optimum anchor. The weights at each iteration are defined proportional to the stress distribution along the anchor obtained in the previous iteration.
A Review of Three Patents Relating to the Development of Novel Inertia-Driven Mechanisms for Igniters On-Board Gun-Fired Munitions
Authors: Murray Richard , Rastegar Jahangir
Published: March 2011

This is a review of a series of three patents issued for inertia igniters: devices which are generally used on-board gun-fired munitions to provide pyrotechnic initiation of a thermal battery. The igniters use the overwhelming firing acceleration to drive various mechanism components which provide event-sensing and a time time-delay in addition to the mechanical striking which ignites the pyrotechnic element of the igniter. The embodiments in the three patents progresses from a novel approach to achieve greater axial compactness while maintaining equivalent performance to a benchmark design, to a two-stage design which expands the range of performance of the event-sensing and time-delay characteristics of the devices, and finally to several novel approaches for producing arbitrarily long delays and the sensing of large impulses in highly compact multi-stage inertia-driven devices. The expansion of the range of operation of such devices is particularly important because prior to these innovative approaches, long delays or the practical measurement of large impulses required electronic methods and an additional tier of electrical power in addition to the thermal battery which is to be initiated.
A Numerical Method for Position Analysis of Compliant Mechanisms With More Degrees of Freedom Than Inputs
Authors: Aten Quentin T. , Zirbel Shannon A. , Jensen Brian D. , Howell Larry L.
Published: March 2011

An under-actuated or underconstrained compliant mechanism may have a determined equilibrium position because its energy storage elements cause a position of local minimum potential energy. The minimization of potential energy (MinPE) method is a numerical approach to finding the equilibrium position of compliant mechanisms with more degrees of freedom (DOF) than inputs. Given the pseudo-rigid-body model of a compliant mechanism, the MinPE method finds the equilibrium position by solving a constrained optimization problem: minimize the potential energy stored in the mechanism, subject to the mechanism’s vector loop equation(s) being equal to zero. The MinPE method agrees with the method of virtual work for position and force determination for under-actuated 1-DOF and 2-DOF pseudo-rigid-body models. Experimental force-deflection data is presented for a fully compliant constant-force mechanism. Because the mechanism’s behavior is not adequately modeled using a 1-DOF pseudo-rigid-body model, a 13-DOF pseudo-rigid-body model is developed and solved using the MinPE method. The MinPE solution is shown to agree well with non-linear finite element analysis and experimental force-displacement data.
Design Preference Elicitation, Derivative-Free Optimization and Support Vector Machine Search
Authors: Ren Yi , Papalambros Panos Y.
Published: March 2011

In design preference elicitation, we seek to find individuals’ design preferences, usually through an interactive process that would need only a very small number of interactions. Such a process is akin to an optimization algorithm that operates with point values of an unknown function and converges in a small number of iterations. In this paper, we assume the existence of individual preference functions and show that the elicitation task can be translated into a derivative-free optimization (DFO) problem. Different from commonly-studied DFO formulations, we restrict the outputs to binary classes discriminating sample points with higher function values from those with lower values, to capture people’s natural way of expressing preferences through comparisons. To this end, we propose a heuristic search algorithm using support vector machines (SVM) that can locate near-optimal solutions with a limited number of iterations and a small sampling size. Early experiments with test functions show reliable performance when the function is not noisy. Further, SVM search appears promising in design preference elicitation when the dimensionality of the design variable domain is relatively high.
Developing Customer Preferences for Concept Generation by Using Engineering Ontologies
Authors: Cao Dongxing , Ramani Karthik , Li Zhanjun , Raskin Victor , Liu Ying , Li Zhanwei
Published: March 2011

As customer preference is viewed as a reflection of desires for product features and even future product opportunities, it is crucial for the generation of design concepts. In this paper, a six-stage methodology is described for developing customer preference by using engineering ontology. The methodology mainly focuses upon understanding the product domain knowledge and preference concepts. A modeling process of the preference ontology for searching, indexing, and retrieving domain knowledge is described. The taxonomies of the customer preferences are elicited by classifying specific concepts. The definition of preference concepts and their ontological relationships are extracted. The objective is to allow product designers to generate customer preference ontologies for their specific products. At first, the documents or catalogs of design requirements are normalized by using ontology-based semantic representation. Design specification formalization is required for system input. A model of preference elicitation from customers is proposed based on ontology knowledge for concept generation. Secondly, the attributes of the customer preferences are classified by identifying the root concepts and developing a kind of preference taxonomy as well as their relationships to each other. They are mapped to engineering ontologies for driving high-level preference concept generation. A customer preference knowledge modeling is developed to construct a thesaurus for preference terms within the domain ontology. Finally, the evaluation and analysis are given to describe the validity of concept generation from customer preferences.
A New 3D Kinematic Model for the Passive Motion of the Tibia-Fibula-Ankle Complex
Authors: Baldisserri Benedetta , Parenti Castelli Vincenzo
Published: March 2011

A great number of kinematic, kinetostatic and dynamic models of human diarthrodial joints, such as the hip, the knee and the ankle, have been presented in the literature. On the contrary, comprehensive models of the lower limb are lacking and often oversimplify its anatomical structures by considering only 2D motion. This paper will focus on the 3D kinematic model of the articulation that involves four bones: the tibia, fibula, talus and calcaneus. In particular, a new spatial equivalent mechanism with one degree of freedom is proposed for the passive motion simulation of this anatomical complex. The geometry of the mechanism is based on the main anatomical structures of the complex, namely the talus, the tibia and the fibula bones at their interface, on the main ligaments of the ankle joint, and on the interosseus membrane of the leg. An iterative refinement process is presented, that provides the optimal geometry of the mechanism which allows the best fitting of simulation versus measurement data. Simulation results show the efficiency of the proposed mechanism that is believed to play an important role for future developments of models of the whole human lower limb.
Potential of the 3-UPU Translational Parallel Manipulator
Authors: Chebbi Ahmed Hachem , Parenti-Castelli Vincenzo
Published: March 2011

The 3-UPU three degrees of freedom fully parallel manipulator, where U and P are for universal and prismatic pair respectively, is a very well known manipulator that can provide the platform with three degrees of freedom of pure translation, pure rotation or mixed translation and rotation according to the relative directions of the revolute axes. Many studies have been reported in the literature on singularities, workspace and joint clearance influence on the platform accuracy of this manipulator. However, much work has still to be done to reveal all the features this topology can offer to the designer. This paper collects the previous most relevant work done on the 3-UPU parallel manipulator and shows the main results in a coherent general frame. The paper proposes new architectures of the 3-UPU manipulator which offer interesting features to the designer. Finally, based on a number of indexes, a procedure is proposed that allows the designer to select the best architecture of the 3-UPU manipulator for a given task.
Investigation of Design Tools as Complexity Management Techniques
Authors: Palmer Gary , Morkos Beshoy , Summers Joshua D.
Published: March 2011

Design tools which appear to manage complexity through their inherent behavior do not appear to have been developed specifically for complexity management. This research explores how complexity is managed within the design process through: the generation of complexity within the design process (sources), the techniques which were used to manage complexity (approaches), and the examination of design tools with respect to complexity. Mappings are developed between the sources, the approaches, and the tools with respect to phases of design. The mappings are propagated through these distinct, yet adjacent domains in order to study how the tools might be able to be used to manage complexity sources found in different stages of the design process. As expected, the highest value for each design tool is found in the stage of design in which the tool is traditionally been used. However, there are secondary ratings which suggest that design tools can be used in other stages of the design process to manage specific aspects of complexity.
Design of Chiral Honeycomb Meso-Structures for High Shear Flexure
Authors: Kolla Avinash , Ju Jaehyung , Summers Joshua D. , Fadel George , Ziegert John C.
Published: March 2011

Chiral honeycombs are auxetic cellular structures that exhibits negative Poison’s ratio. Chiral honeycombs are structures arranged in an array of cylinders connected by ligaments. Four different configurations of these geometries with 4- and 6- ligaments attached are investigated for its use in shear layer of non-pneumatic wheel. The objective of the study is to find an ideal geometry for the shear layer while meeting its requirements of shear properties (about 6.5 MPa effective shear modulus and 0.15 maximum effective shear strain) with polycarbonate as base material. Finite Element (FE) based numerical tests are carried out and optimum chiral meso-structures are found for the target shear properties. Parametric studies on geometries are also conducted to find the effect of geometries on the target properties. The effect of cell wall thickness is studied and the optimum thickness is suggested to meet the target requirements. Effect of direction of shear loading has been studied on each different configuration in order to minimize the effect of direction of loading.
Active Elimination of Oil Whip and Dry Whip Through the Use of Electromagnetic Exciter
Authors: Fan Chen-Chao , Tsao Wen-Chang , Pan Min-Chun , Syu Jhe-Wei
Published: March 2011

Oil whip induces self-excited vibration in fluid-handling machines, and what is worse, it can cause self-excited reverse precessional full annular rub, known as “dry whip”, which is a secondary phenomenon resulting from a primary cause, and may lead to a catastrophic failure of machines; that is, “coincidence of oil whip and dry whip” that occurs repeatedly with constant frequency and amplitude in small clearance cases. This paper presents a technique using an electromagnetic exciter (EE), that can raise the threshold of stability of a rotary machine and then eliminate the coincidence of oil whip and dry whip in the normal operational range. In addition, an experimental rotor rig, a general model of a rotor/beating system with an EE and corresponding governing motion equations, computation of stiffness supplied by the EE, design example, stability judged by root locus plots, and criterion for eliminating the coincidence of the oil whip and dry whip are constructed, derived and established. Experimental results demonstrate that the coincidence of oil whip and dry whip of the rotary machine can be removed effectively. These results can be used to diagnose rub and fluid-induced instability in this kind of rotary machine.
Research and Development of Microwire Handling Devices
Authors: Shenoy Amogh J. , Liou Frank W. , Barua Shyam
Published: March 2011

This paper focuses on the research and development of wire handling devices for microdiameter wires of various sizes. Microsized wires and tools are gaining importance in aerospace technology, medical device manufacturing and in the semiconductor industry. Development of microwire handling devices is complicated and difficult due to the size of the wire and the need for high accuracy for its use. The aim of this work was to develop a compact, robust, and highly precise device. This paper presents a systematic methodology for the development of a high-precision microwire handling device. The device can accurately feed wires ranging as low as 0.05 mm in diameter. The wire handling device must satisfy the following three criteria: (1) it must continuously feed wire without slippage and kinking; (2) it must ensure repeatability with great accuracy; (3) and it must handle wire of various sizes. The device was experimentally tested for initial design failures, high precision, and repeatability. A practical example for laser deposition is presented here to illustrate the effectiveness of the proposed approach.
Simulation-Based Design of Exoskeletons Using Musculoskeletal Analysis
Authors: Agarwal Priyanshu , Narayanan Madusudanan S. , Lee Leng-Feng , Mendel Frank , Krovi Venkat N.
Published: March 2011

Exoskeletons are a new class of articulated mechanical systems whose performance is realized while in intimate contact with the human user. The overall performance depends on many factors including selection of architecture, device, parameters and the nature of the coupling to the human, offering numerous challenges to design-evaluation and refinement. In this paper, we discuss merger of techniques from the musculoskeletal analysis and simulation-based design to study and analyze the performance of such exoskeletons. A representative example of a simplified exoskeleton interacting with and assisting the human arm is used to illustrate principal ideas. Overall, four different case-scenarios are developed and examined with quantitative performance measures to evaluate the effectiveness of the design and allow for design refinement. The results show that augmentation by way of the exoskeleton can lead to a significant reduction in muscle loading.
Comprehensive Reduced-Order Models of Electrostatically Actuated MEMS Switches and Their Dynamics Including Impact and Bounce
Authors: Snow Michael G. , Bajaj Anil K.
Published: March 2011

As MEMS technology develops it is becoming better understood that MEMS designers must account for the large uncertainties characteristic of the relevant manufacturing processes. Uncertainty quantification tasks the designer with evaluating many different possible outcomes from the manufacturing process which creates a demand for models that are accurate and comprehensive, yet fast to evaluate. This work presents a comprehensive reduced-order model of electrostatically actuated switches incorporating a range of effects that are typically included only in FE modeling codes. Specifically, the model accounts for variable electrode geometry, stretching of centerline or large displacement effects, fringing field, squeeze film and rarefied gas damping, and allows for elastic contact with the dielectric substrate. Individual compact models for each of these effects are taken from literature and included in the model for the system. The dielectric substrate is modeled as an elastic foundation. The resulting partial differential equation for the switch modeled as a beam is discritized via a Galerkin method into ordinary differential equations for modal amplitudes. The Galerkin method uses the linear un-damped mode shapes of the beam to approximate the solution. Both cantilever and fixed-fixed type switches are analyzed. Static equilibrium solutions as a function of the applied voltage are developed along with their stability. Static pull-in voltages, first time of switch closure, and voltage for lift-off are studied with the model. To capture the contact dynamics, the contact condition is evaluated with the substrate divided into a large number of elements and the contact force is projected on to the beam basis functions. In the case of cantilever geometry and slow voltage variations, three stable regimes of contact configuration and hysteresis between them are demonstrated.
Material Parameter Identification of Viscoplastic Model for Solder Alloy in Electronics Package Using Bayesian Calibration
Authors: Gang Jinhyuk , Choi Jooho , Lee Bonghee , Joo Jinwon
Published: March 2011

In this study, a method of computer model calibration is applied to quantify the uncertainties arising in the material characterization of the solder joint in the microelectronics package subject to a thermal cycle. In this study, all uncertainties are addressed by using a Bayesian calibration approach. A special specimen that characterizes the solder property due to the shear deformation is prepared, from which the Moire´ fringe is measured by running a thermal cycle. Viscoplastic finite element analysis procedure is constructed for the specimen based on the Anand model. Gaussian process model known as Kriging is employed to approximate the original finite element analysis (FEA) model. Posterior distribution for the unknown Anand parameters is formulated from the likelihood function for joint full-field displacements of computation and experiment. Markov Chain Monte Carlo (MCMC) method is employed to simulate posterior distribution. As a result, the displacements are predicted in the form of confidence interval. The results show that the proposed approach can be a useful tool in the estimation of the unknown material parameters in a probabilistic manner by effectively accounting for the uncertainties due to the experimental and computational models.
Nonlinear Vibration of Plates and Higher Order Theory for Different Boundary Conditions
Authors: Amabili Marco , Karagiozis Kostas , Farhadi Sirwan , Khorshidi Korosh
Published: March 2011

There are numerous applications of plate structures found in structural, aerospace and marine engineering. The present study extends the previous work by Amabili and Sirwan [1] investigating the performance of isotropic and laminate composite rectangular plates with different boundary conditions subjected to an external point force with an excitation frequency that lies in the neighbourhood of the fundamental mode of the plate. The analysis is performed using three different nonlinear plate theories, namely: i) the classical Von Ka´rman theory, ii) first-order shear deformation theory, and iii) third-order shear deformation theory. Three different boundary conditions are considered in the investigation: a) classical clamped boundary conditions, b) simply-supported ends with immovable edges, and c) simply-supported ends with movable boundaries. In addition, the effect of thickness was also considered in the analysis and different values for the plate thickness were assumed. The results investigate the accuracy of lower order theories versus higher order shear deformation theories, the effect of boundary conditions and highlight the differences in the responses obtained from isotropic and laminate composite rectangular plates.
Product Family Deployment Through Optimal Resource Allocation Under Market System
Authors: Akai Ryota , Amaya Hirofumi , Fujita Kikuo
Published: March 2011

A series of products, i.e. a product family is deployed for effectively and flexibly meeting with a variety of customer’s needs under a given product platform. Since such a deployment consumes various engineering resources and simultaneously brings profits gradually over the time sequence, when and how respective modules are designed and respective products are launched to the market must be rationally planed. Further, as a nature of product families, module commonalization accelerates the deployment but infuses some overheads on features and production cost. This paper investigates such a product family deployment problem under the optimal design viewpoint. After some general discussions, a mathematical model of dynamic design decisions is conditionally developed by integrating a combinatorial optimization technique for decision of module selection on commonalization and a market system model with discrete choice analysis and for describing the compromise among sequence of product rollout, arrangement of product lineup, required engineering resource, expected profit, etc. Then, the compromise among those factors is illustrated through the case study on a simplified deployment problem of circuit boards for digital television sets. Finally, an optimal planning approach for product family deployment and accompanied resource allocation is envisioned based on the developed model and findings from the case studies.
Kinematics Analysis of the Exechon Tripod
Authors: Zoppi Matteo , Zlatanov Dimiter , Molfino Rezia
Published: March 2011

The Exechon 5-Axis Parallel Kinematic Machine (PKM) is a successful design created in Sweden and adopted by many producers of machine tools around the world. A new version of the manipulator is being developed as a component of a mobile self-reconfigurable fixture system within an inter-European project. The basic Exechon architecture consists of a 3-degree-of-freedom (dof) parallel mechanism (PM) connected in series with a two- or three-dof spherical wrist. The PM has two UPR (4-dof) legs, constrained to move in a common rotating plane, and an SPR (5-dof) leg. The paper presents the kinematic analysis of both the PM and the hybrid parallel-serial architecture. We describe the complex three-dimensional motion pattern of the PM platform, derive the kinematic equations and provide explicit solutions for the inverse kinematics.
Social Intelligence for a Task-Driven Assistive Robot
Authors: Nejat Goldie , Ficocelli Maurizio
Published: March 2011

The objective of a socially assistive robot is to create a close and effective interaction with a human user for the purpose of giving assistance. In particular, the social interaction, guidance and support that a socially assistive robot can provide a person can be very beneficial to patient-centered care. However, there are a number of conundrums that must be addressed in designing such a robot. This work addresses one of the main limitations in the development of intelligent task-driven socially assistive robots: Robotic control architecture design and implementation with explicit social and assistive task functionalities. In particular, in this paper, a unique emotional behavior module is presented and implemented in a learning-based control architecture for human-robot interactions (HRI). The module is utilized to determine the appropriate emotions of the robot, as motivated by the well-being of the person, during assistive task-driven interactions. A novel online updating technique is used in order to allow the emotional model to adapt to new people and scenarios. Preliminary experiments presented show the effectiveness of utilizing robotic emotional assistive behavior during HRI in assistive scenarios.
Linkages That Transfer Rotations to Radially Reciprocating Motion
Authors: Wei Guowu , Dai Jian S.
Published: March 2011

Stemming from study of polyhedral and spheroidal linkages and investigation of reciprocating motion of the PRRP chain, this paper presents four overconstrained linkages that are capable of transferring rotations to radially reciprocating motion. The linkages connected by revolute joints are of symmetrical arrangement and mobility one and are analysed by using the screw-loop equation method. The paper further investigates geometry and kinematics of the linkages and reveals their kinematic characteristics, leading to the constraint equation.
Investigating the Significance of “One-to-Many” Mappings in Multiobjective Optimization
Authors: Simov Peter , Ferguson Scott
Published: March 2011

Significant research has focused on multiobjective design optimization and negotiating trade-offs between conflicting objectives. Many times, this research has referred to the possibility of attaining similar performance from multiple, unique design combinations. While such occurrences may allow for greater design freedom, their significance has yet to be quantified for trade-off decisions made in the design space (DS). In this paper, we computationally explore which regions of the performance space (PS) exhibit “one-to-many” mappings back to the DS, and examine the behavior and validity of the corresponding region associated with this mapping. Regions of interest in the PS and DS are identified and generated using indifference thresholds to effectively “discretize” both spaces. The properties analyzed in this work are a mapped region’s location in the PS and DS and the total hypervolume of the mappings. Our proposed approach is demonstrated on two different multiobjective engineering problems. The results indicate that one-to-many mappings occur in engineering design problems, and that while these mappings can result in significant design space freedom, they often result in notable performance sacrifice.
Towards a Recursive Hexapod for the Multidimensional Mechanical Testing of Composites
Authors: Michopoulos John G. , Hermanson John C. , Iliopoulos Athanasios
Published: March 2011

Automated inverse methods for material constitutive characterization under multidimensional loading conditions has motivated the custom design, manufacturing and utilization of mechatronic loading machines. This present paper reports on the architecture of a mechatronic system capable of enforcing 6-DoF kinematic boundary conditions on deformable material specimens under testing, while at the same time measuring both the imposed kinematics and the corresponding reaction forces in a fully automated manner. This system has a recursive nature as it consists of a hexapod configuration that repeats itself six times. In addition to the architecture, we also present the historical evolution, and current status of its manufacturing implementation and the initial fielding of our system for composite material testing and characterization.
An Integrated Methodolgy for Fixture Design in Mesoscale Machining Taking Into Account Cutting Process Dynamics
Authors: Leonesio Marco , Cau Nicola , Rippere Troy B. , Wiens Gloria J. , Bianchi Giacomo
Published: March 2011

In this paper an approach for limiting regenerative chatter in meso-milling operations is discussed, based on the optimal selection of work piece dynamic compliance, to be obtained by using stiffness-adjustable work piece holder devices, called “fixels”. In order to investigate the phenomenon, a FEM model of a meso-machine tool has been developed and coupled with the fixels model. Then, the cutting capability enhancement due to the tuned fixels has been evaluated for a significant meso-milling operation with a commercial tool.
Developing Biomimetic Guidelines for the Highly Optimized and Robust Design of Complex Products or Their Components
Authors: Wadia Anosh P. , McAdams Daniel A.
Published: March 2011

Improved complex system design methods can lead to innovative, efficient, and robust product designs. This research aims at improving the design of products that compose a portion of, or exist within, a complex system. Before attempting to improve product designs, one requires a better understanding and characterization of complex systems. One method to characterize optimized and robust complex systems is to use the Theory of Highly Optimized Tolerance (HOT). The theory states that highly optimized and tolerant complex systems are robust in conditions for which they were designed, but fragile in the face of unanticipated events. Highly robust and optimized complex systems are abundant in the biological domain. In fact, nature represents a vast resource for innovative solutions to varied design problems. Leveraging these solutions to solve engineering problems is often referred to as biomimetic design. This research analyzes twenty bio-inspired engineering products including the biological system from which they were derived. The HOT theory is used analyze the biomimetic systems and identify the inherent characteristics that make the designs robust to their environment. These characteristics were reviewed to identify common features and trends present within the information transfer between the biological and engineering domains. Finally, the inferred features and trends were abstracted into usable guidelines stated as nine biomimetic design guidelines. Similar to the forty Theory of Inventive Problem Solving principles, these bio-inspired guidelines could aid engineers in developing innovative and robust solutions to design problems. In fact, a similarity between some of the biomimetic design guidelines and TRIZ principles is observed. This correlation suggests that solutions perceived as innovative in the engineering domain match those in nature.
Dexterity and Workspace Analysis of Two Soft Robotic Manipulators
Authors: Trivedi Deepak , Lesutis Daniel , Rahn Christopher D.
Published: March 2011

Soft robotic manipulators are continuum robots made of soft materials that undergo continuous elastic deformation and produce motion with a smooth backbone curve. These manipulators offer significant advantages over traditional manipulators due to their ability to conform to their surroundings, move with dexterity and manipulate objects of widely varying size using whole arm manipulation. Soft robotic manipulators are complex and difficult to design, model and fabricate. In this paper, we present a cost effective design for a pneumatic air muscle based soft robotic manipulator in which the actuators for the distal section extend from the base to the tip of the arm, thereby simplifying the pneumatic design and eliminating the need for endplates. We compare the workspace and dexterity of continuous tube (CT) design with a previously developed OctArm type manipulator and conclude that although the two designs have comparable workspace area, the OctArm workspace has better dexterity characteristics.
Feedback Control and Exogenous Force Estimation for Improved Single-Molecule Experiments
Authors: Cole Daniel G.
Published: March 2011

This article explores two types of feedback used to control optical traps: position feedback, which was shown to be equivalent to force feedback, and integral feedback. The ability of each of these types of feedback to lower the measurement SNR in single molecule experiments is evaluated and compared to the open-loop case. While position feedback did not result in any improvement in the SNR, the case of integral feedback results in an improvement. Integral feedback is shown to improve the SNR of the measured signal of interest, and is relatively robust and easy to implement. It is also shown that integral feedback acts as an exogenous force estimator.
A Virtual Machining Model for Sustainability Analysis
Authors: Shao Guodong , Kibira Deogratias , Lyons Kevin
Published: March 2011

Sustainability has become a very significant research topic since it impacts many different manufacturing industries. The adoption of sustainable manufacturing practices and technologies offers industry a cost effective route to improve economic, environmental, and social performance. As a major manufacturing process, the machining system plays an important role for sustainable manufacturing on the factory floor. Therefore, technologies for monitoring, analyzing, evaluating, and optimizing the sustainability impact of machining systems are critical for decision makers. Modeling and Simulation (M&S) can be an effective tool for success of sustainable manufacturing through its ability to predict the effect of implementing a new facility, process without interrupting real production. This paper introduces a methodology that provides a traditional virtual Numerical Control (NC) machining model with a new capability — to quantitatively analyze the environmental impact of machining system based on Life Cycle Assessment (LCA). The objective of the methodology is to analyze the sustainability impacts of machining process and determine a better plan for improving the sustainable performance of machining system in a virtual environment before work orders are released to the shop floor. Testing different scenarios with simulation models ensures the best setting option available can be chosen. The virtual NC model provides the necessary data for this assessment. In this paper, a list of environmental impact indicators and their metrics has been identified, and modeling elements for sustainable machining have been discussed. Inputs and outputs of the virtual machining model for sustainable machining are described. A case study to experiment the proposed methodology is discussed.
A Volumetric Contact Model Approach for Off-Road Tire/Soil Dynamic Simulation
Authors: Petersen Willem , McPhee John
Published: March 2011

A novel off-road tire model for planetary rover applications is created to investigate the mobility of such exploration vehicles. A volumetric contact model in series with a hyperelastic Bekker soil model is used to derive the contact forces between a deformable tire and soft soil. The volumetric off-road tire model is derived for a cylinder rolling on flat ground, and the rolling resistance can be directly calculated from the volumetric contact model. The longitudinal and lateral tire forces are calculated by integrating the shear stress over the contact patch. To check the consistency of the tire model, it is simulated using a simplified 14 degree of freedom model often used in vehicle dynamics simulations. The results are compared against those of a conventional rigid tire simulated under the same conditions. The deformable tire is shown to generate a 34% higher traction force than the rigid tire. In another steering scenario, the feasibility of this model for handling anyalses is verified.
Precise Assembly of Metallic Nanoclusters as Building Blocks of Nanostructures: A Molecular Dynamics Study
Authors: Mahboobi S. H. , Meghdari A. , Jalili N. , Amiri F.
Published: March 2011

Molecular dynamics simulations are used to study the assembly of metallic nanoclusters using manipulation process. These particles are assumed as potential building blocks for bottom-up manufacturing of nanoscale structures. One of the key factors in the assembly of nanoclusters is their precise positioning by a manipulation system. Prediction of the corresponding behavior under the influence of working conditions is of crucial importance for planning of controlled positioning and assembly of nanoclusters. The focus of the present research is on ultra-fine metallic nanoclusters. The effects of material type and manipulation strategy on the success of the process are investigated by molecular dynamics. Such qualitative simulation studies can evaluate the chance of success of a certain nanopositioning scenario regarding different working conditions before consuming high experimental expenses.
Type Synthesis Principle and Practice of Flexure Systems in the Framework of Screw Theory: Part I—General Methodology
Authors: Yu J. J. , Li S. Z. , Pei X. , Su Hai-jun , Hopkins J. B. , Culpepper M. L.
Published: March 2011

The systematic methodologies involved in type synthesis of flexure systems are no doubt helpful to generate one and more high-performance precision machine designs at the stage of conceptual design with a rapid and effective way. This paper provides a systematic formulation of the type synthesis of parallel, serial, and hybrid flexure systems via a mapping from a geometric concept to physical entity. The whole type synthesis principle is built upon screw system theory and the geometric Freedom and Constraint Topology (FACT) approach, also combining with other concepts and methods including equivalent compliance mapping, building block etc, which enables the type synthesis of flexure systems deterministic, simple and practical. After that, Type synthesis procedure for various flexure systems are elaborated with examples. As a result, as many specified-DOF (Degree of Freedom) flexure systems as possible can be found and therefore pave the way for obtaining an optimal configuration.
Multiscale Variability and Uncertainty Quantification Based on a Generalized Multiscale Markov Model
Authors: Wang Yan
Published: March 2011

Variability is inherent randomness in systems, whereas uncertainty is due to lack of knowledge. In this paper, a generalized multiscale Markov (GMM) model is proposed to quantify variability and uncertainty simultaneously in multiscale system analysis. The GMM model is based on a new imprecise probability theory that has the form of generalized interval, which is a Kaucher or modal extension of classical set-based intervals to represent uncertainties. The properties of the new definitions of independence and Bayesian inference are studied. Based on a new Bayes’ rule with generalized intervals, three cross-scale validation approaches that incorporate variability and uncertainty propagation are also developed.
Singularity Tolerant Robotic Manipulation for Autonomous Field Tracking in an Unknown Environment
Authors: Jeon Soo
Published: March 2011

This paper presents a comprehensive motion control strategy for the autonomous operation of robotic manipulators combined with the sensor-driven recursive estimation of an unknown field of interest. The spatial distribution of the environmental phenomenon is modeled by a radial basis function (RBF) network and their weight parameters are estimated by a recursive least square (RLS) method using the collective measurements from the on-board sensors mounted to the manipulator. The asymptotic tracking has been simultaneously achieved by the control law based on the gradient of the estimated field. Since the target location cannot be known a priori, the motion controller has to be designed in explicit consideration of tolerating the singular configuration of the manipulator kinematics. By using the null space decomposition of the task space for the Jacobian near the singularities, a systematic method is suggested to command the task space control law in spite of the singular configurations. Simulation results using the three link planar robot are presented to support the main ideas.
Flywheel Based Mechanical Hybrid System: Simulation of the Fuel Consumption Benefits of Various Transmission Arrangements and Control Strategies
Authors: Brockbank Chris , Body Will
Published: March 2011

Flywheel based mechanical hybrid technology is under development for Motorsport, Automotive and Commercial Vehicle applications. Originally a European development, North American mechanical hybrid applications are now underway. The mechanical hybrid system recovers kinetic energy from the vehicle during braking to a high-speed, rotating flywheel via a variable drive system. When compared to an electric motor / battery arrangement, the mechanical hybrid system offers benefits in cost, weight, package, efficiency and ultimately fuel consumption. A number of UK Government funded projects applying flywheel based mechanical hybrid systems are ongoing, developing the technology and building mechanical hybrid equipped demonstrator vehicles. Participants include OEM’s Jaguar Land Rover, Ford, JCB and Optare using advanced technology from Allison Transmission Inc, Flybrid Systems, Ricardo, SKF and Torotrak. The Torotrak torque controlled, variable drive technology is a key component within the mechanical hybrid system. As part of the development process, all aspects of the mechanical hybrid system are under investigation (such as the required energy storage, rates of energy recovery, etc) including the variety of different physical architectures for the variable drive system. Multiple configuration options are available including direct drive, epicyclic shunted, range extended CVT and epicyclic shunted IVT arrangements. In addition, the flywheel and variable drive system can be connected to the powertrain in a variety of different locations from engine to transmission to final drive. This paper describes the simulation of the mechanical hybrid system with focus on the impact on the fuel consumption benefit, over multiple drive cycles, of the variable drive configuration, the location of the variable drive & flywheel system and the control strategy options.
Development of Game Theoretic Protocols for Multilevel Design
Authors: Sinha Ayan , Mistree Farrokh , Allen Janet K.
Published: March 2011

The effectiveness of the use of game theory in addressing multi-objective design problems has been illustrated. For the most part, researchers have focused on design problems at single level. In this paper, we illustrate the efficacy of using game theoretic protocols to model the relationship between multidisciplinary engineering teams and facilitate decision making at multiple levels. We will illustrate the protocols in the context of an underwater vehicle with three levels that span material and geometric modeling associated with microstructure mediated design of the material and vehicle.
Combining User Workflow and System Functions in Product Development
Authors: van Beek Thom J. , Tomiyama Tetsuo
Published: March 2011

This research addresses two aspects of multi disciplinary product development; understanding what the customer needs and translating this knowledge effectively into a transparent system architecture. A clear overview and understanding of this architecture can be obtained by using function models. How to make an effective translation from the customer needs to function models is not trivial. The approach taken in this research is to discuss, develop, negotiate, align and model the intended users’ workflow of the system. Multiple stakeholders (e.g. buyer, user, marketers, application experts, architects, designers and third party suppliers) should participate in this process. The user workflow is systematically mapped to a system function model. The contributions of this paper can be divided in two. First a systematic and easily applicable design method to capture and validate user requirements in a multi disciplinary design process using explicit workflow models is proposed. Secondly a systematic method of translating user workflow models to system function models will be given.
Completely Eliminating the Singularities of a 3-DOF Planar Parallel Robot With Only One Degree of Actuation Redundancy
Authors: Rakotomanga Novona , Bonev Ilian A.
Published: March 2011

The Cartesian workspace of an n-DOF parallel robot (n < 6) is generally divided by singularity hyper-surfaces of dimension n−1. A common approach to reducing the dimension of the singularity manifold is to use actuation redundancy. However, in all previously reported works, adding one redundant actuator reduces the dimension of the singularity manifold by only one. This paper is the first to demonstrate that a properly designed actuation redundancy can be much more effective than this. Specifically, a 3-RPR design is presented in which the mobile platform and the base are equilateral triangles and show that adding a single RPR leg connecting the centers of these two triangles completely eliminates the singularities of the robot, which are otherwise a surface in the Cartesian space.
A Heart Stabilization Device Exploiting Gyroscopic Actuation: Design and Control
Authors: Gagne Julien , Piccin Olivier , Laroche E´douard , Gangloff Jacques
Published: March 2011

The heart motion is the main hindrance to the development of recent less invasive surgical techniques in the cardiac field. The problem can be partially solved by maintaining the intervention area with stabilizers but the remaining displacements are still important. We propose a device able to exert a torque on the stabilizer in order to compensate for heart action in real time. The system is based on gyroscopic actuation associated with acceleration sensing which allows to free from grounding constraints. In this paper we present first the system architecture and its mechanical model. We describe afterward the prototype design and the experimental setup. Then we detail the control strategy which includes a Kalman filter dedicated to the observation of both the state and the disturbance signals. Several control laws are compared based on disturbance compensation and static feedforward, taking into account gyroscopic actuation specificities. Finally these controls are tested in simulation on a more detailed model.