bluuebunny/crossref_metadata_2025 huggingface dataset:
An Autonomous Surgical Robot Applied in Cochleostomy
Authors: Brett P. N. , Taylor R. P. , Proops D. , Coulson C. , Reid A. , Griffiths M. V.
Published: May 2009

In this paper a robotic micro-drilling technique for surgery is described. The device has been deployed in cochleostomy, a precise micro-surgical procedure where the critical stage of controlling penetration of the outer bone tissue of the cochlea is achieved without penetration of the endosteal membrane at the medial surface. The significance of the work is that the device navigates by using transients of the reactive drilling forces to discriminate cutting conditions, state of tissue and the detection of the medial surface before drill break-out occurs. This is the first autonomous surgical robot to use this technique in real-time as a navigation function in the operating room and unlike other fully autonomous surgical robotic processes it is carried out without the use pre-operative data to control the motion of the tool. To control tool points in flexible tissues requires self-referencing to the tissue position in real time. There is also the need to discriminate deflections of the tissue, tissue interface, involuntary patients/ tissue movement and indeed movement induced by the drill itself which require different strategies to be selected for control. As a result of the design of the final system, the break-out process of the drill can either controlled to the required level of pro-trusion through the flexible interface or can be avoided altogether, with the drill bit at the medial surface. This enables, for the first time, the control of fine penetration with such great precision.
A Proposal of Classification and Guideline of Selection for Design Modeling Methods
Authors: Asanuma Takashi , Kawashima Jumpei , Ujiie Yoshiki , Matsuoka Yoshiyuki
Published: May 2009

In recent years the demands of users and the social problems have been diverse. In design, the diverse demands of users and problems of the society have created increasingly complex design problems. Therefore, it is important to understand values and images of the design objects and analyze the relation among design objects, human beings and its environment to respond to the complicated design problems. A number of design modeling methods that realize above points have been proposed. Consequently, it is necessary for designers and engineers to derivate the exact design solution that responds to the complicated design problems. However, the framework of design modeling methods in design has not been established. Moreover, most of the current studies on the methods only respond to the problems in each aspect of design [1]. Therefore, designers and engineers apply the design modeling methods in each design process based on their knowledge and experiences. The guideline of selection for the application of design modeling methods has not been shown. Consequently, the guideline for selecting the design modeling methods is needed for designers and engineers to apply the methods appropriately in design.
Formulation of a State Equation Including Fractional-Order State-Vectors
Authors: Kuroda Masaharu
Published: May 2009

In recent years, applications of fractional calculus have flourished in various science and engineering fields. Particularly in engineering, control engineering appears to be expanding aggressively in its applications. Exemplary are the CRONE controller and the PIλDμ controller, which is categorizable into applications of fractional calculus in classical control theory. A state equation can be called the foundation of modern control theory. However, the relationship between fractional derivatives and the state equation has not been examined sufficiently. Consequently, a systematic procedure referred to by every researcher on the fractional-calculus side or control-theory side has not yet been established. For this study, therefore, involvement of fractional-order derivatives into a state equation is demonstrated here for ready comprehension by researchers. First, the procedures are explained generally; then the technique to incorporate the fractional-order state-vector into a conventional state equation is given as an example of the applications. The state-space representation in this study is useful not only for modeling a controlled system with fractional dynamics, but also for design and implementation of a controller to control fractional-order states. After we complete installation of the basic parts, we can apply the benefits of modern control theory, including robust control theories such as H-infinity and μ-analysis and synthesis in their integrities, to this fractional-order state-equation.
Rollover Case Study Simulation for HMMWV Military Vehicle
Authors: Hahn Youngwon , Ma Zheng-Dong , Hulbert Gregory M. , Kikuchi Noboru
Published: May 2009

In this research, the rollover simulation for military vehicle, HMMWV (High Mobility Multi-purposed Wheeled Vehicle), is performed using commercial software ADAMS. Two rollover test procedures, J-turn and Fishhook, are simulated following NHTSA rollover test report with the variation of the vehicle speed and the design variables — the stiffness of body mount bush and stabilizer bar, which can be easily modified in the field. Around the critical velocity at which rollover is occurred, rollover phenomena are assessed with the variation of the design variable. Among roll rate and tire lift-off time, tire lift-off time is shown as a good rollover index from the simulation results. The discussion of the sensitivity results for the design variable is also provided.
Motion Planning and Control of a Tractor With a Steerable Trailer Using Differential Flatness
Authors: Ryu Ji-Chul , Agrawal Sunil K. , Franch Jaume
Published: May 2009

This paper presents a methodology for trajectory planning and tracking control of a tractor with a steerable trailer based on the system’s dynamic model. The theory of differential flatness is used as the basic approach in these developments. Flat outputs are found that linearize the system’s dynamic model using dynamic feedback linearization, a subclass of differential flatness. It is demonstrated that this property considerably simplifies motion planning and the development of controller. Simulation results are presented in the paper, which show that the developed controller has the desirable performance with exponential stability.
A Numerical Study of Non-Symmetric Joints
Authors: Berger Edward
Published: May 2009

A great deal of analytical, numerical, and experimental research has focused on characterizing symmetric lap-type joints, in which the joint connects dynamic systems with nominally the same descriptions. In this paper, we numerically examine dynamically non-symmetric jointed structures. Starting with the analytical treatments of Pratt and Williams (1981) as verification of our simulation model and approach, we then introduce structural stiffness asymmetries ranging from small perturbations to large differences. The results are presented in both the time and frequency domains, and the role of the dynamic asymmetry is critically examined. The results of this numerical study suggest that both the relative displacement profile and the stick-slip behavior at the joint are sensitive to the dynamics of the two substructures, with frequency tuning of the substructures being an important indicator of joint performance.
Control of an Impacted Cantilever to Maintain a Constant Magnitude for a Specific Frequency Component of the Response
Authors: Numatsu Masatoshi , Yabuno Hiroshi , Dick Andrew J. , Kuroda Masaharu , Ashida Kiwamu , Balachandran Balakumar
Published: May 2009

In this effort, a new control method to keep the state of the arbitrary impact between the tip of the excited cantilever and the object surface is proposed. It is known that various bifurcations of the responses of the beam occur according to impact conditions and variation of the excitation frequency. We propose a control method to keep the magnitude of a specific frequency component constant and the state of particular impact independent of changes in the distance between the cantilever and the contact surface. For this purpose, a real-time signal processing method is suggested to determine the magnitude of the frequency component at half the excitation frequency. A servo system is designed to control the center of the excitation precisely for the above purpose. Finally, validity of the proposed control method is confirmed by experiments.
Path Planning for Automated Robot Painting
Authors: McPherson Finlay N. , Corney Jonathan R. , Sung Raymond C. W.
Published: May 2009

This paper describes the analysis work underlying the path-planning algorithm for a robotic painting system. The system requires no bespoke production tooling and fills an automation gap in rapid prototyping and manufacturing technology that is currently occupied by hand painting. The system creates images by exposing individual pixels of a photographic coating with a robot-mounted laser. The painting process requires no physical contact so potentially images could be developed on any shape regardless of its complexity: As objects can only be “painted” when their surface can be “hit” (i.e. exposed) by the light beam the system requires six degrees of freedom to ensure all overhanging or reentrant areas can be exposed. The accuracy of serial robots degrades with the length of the kinematic chain (in other words six axis robots cannot position themselves with the same accuracy as four axis ones). Consequently to ensure high precision in the location and orientation of the light source, the object being exposed is mounted on a rotary tilt table within the workspace of a four-axis robot. This gives a six-degree of freedom positioning system composed of two separate kinematic chains. Although the resulting system is accurate the problems of constructing a coordinated path that allows the light beam to efficiently sweep (i.e. cover) the surface regardless of its geometry are challenging. This paper describes the difficulties and, after reviewing existing path planning algorithms, a new algorithm is introduced firstly by describing the nature of the system’s configuration space and then further developing this concept as an alternative to a previously described planning algorithm. Having outlined the approach the paper presents a kinematic model for the system and compares the configuration space approach to a purely Cartesian planning approach.
A Uniform Rotationless Formulation of Flexible Multibody Dynamics: Conserving Integration of Rigid Bodies, Nonlinear Beams and Shells
Authors: Betsch Peter , Sa¨nger Nicolas
Published: May 2009

A uniform framework for rigid body dynamics and nonlinear structural dynamics is presented. The advocated approach is based on a rotationless formulation of rigid bodies, nonlinear beams and shells. In this connection, the specific kinematic assumptions are taken into account by the explicit incorporation of holonomic constraints. This approach facilitates the straightforward extension to flexible multibody dynamics by including additional constraints due to the interconnection of rigid and flexible bodies. We further address the design of energy-momentum schemes for the stable numerical integration of the underlying finite-dimensional mechanical systems.
OWL-Based Product Ontology Architecture and Representation for Sharing Product Knowledge on a Web
Authors: Lee Jae-Hyun , Suh Hyo-Won
Published: May 2009

A collaborative product development environment requires sharing of product information among its participants. Product knowledge models and international standards have been developed for product information sharing. However, their models have limitations in representing their semantics explicitly, so a computer can not understand their semantics properly. It results in lack of information sharing. Recently, ontology gets attentions for automatic knowledge sharing because it can specify the semantics explicitly and logically. In addition, ontology-related standard language, such as web ontology language (OWL), is also proposed. In this paper, we propose an architecture for an ontology-based product knowledge and a product web ontology language (POWL) based on OWL. The architecture consists of three-level ontologies; meta-, generic and particular product ontology. The meta-product ontology is derived from previous top-level ontologies such as SUMO, DOLCE and Guarino’s ontology. The generic product ontology is developed to provide comprehensive knowledge primitives representing product knowledge. A particular product ontology specify knowledge about a specific product such as car, telephone, ship, etc., and it is defined based on the generic product ontology. Meanwhile, POWL has product knowledge primitives defined in the generic product ontology, and it can be transformed to OWL. So users can define the specific product knowledge based on POWL. We implement the tranformation logic with XSLT and demonstrate a POWL usage with an example.
Practical Implementation Issues and Their Effects on Damping Performance of Pulse-Switched Piezoelectric Shunts for Vibration Control
Authors: Clark William W. , Sobek Robert D.
Published: May 2009

The concept of switching the shunt circuit of a passive piezoelectric material used for vibration control has been studied by various researchers for the past decade. The technique involves connecting and disconnecting the piezoelectric actuator to and from a resistive, capacitive, or inductive shunt circuit in real time. By setting the switch timing appropriately, one can achieve significant damping in the accompanying structure. While the technique has been shown to be very effective in lab settings, the practical performance can be affected by several factors. This paper addresses some of the practical issues of switched shunts and analyzes the expected performance as various parameters vary in the system, including i) the original damping in the structure, ii) the relative stiffness of the structure and the actuator, and iii) mistiming of the shunt switching process. A simple single degree-of-freedom system with a switched resistor-inductor (RL) shunt is used in the study. The paper presents a mathematical model of the system and switched-shunt, and then presents the results of simulations that analyze the expected damping performance.
A Study on Laser Engineered Net Shaping Prototyping Technology
Authors: Xu Zhenyu , Amano R. S. , Rohatgi Pradeep
Published: May 2009

The objectives of this work are to study Laser Engineered Net Shaping (LENS™) produced materials and identify the microstructures. Numerical method was used to examine the influence of materials’ type and LENS™ process parameters on the forming of the specific microstructures from thermodynamics and fluid dynamics point of view. Samples of 4140 low alloy steel and 316L stainless steel were examined, microstructures of samples were used to estimate the corresponding cooling rate, and the cooling rate was compared with the numerical results.
Experiments on Quasi-Periodic Wheel Shimmy
Authors: Taka´cs De´nes , Ste´pan Ga´bor
Published: May 2009

The lateral vibration of towed wheels — so-called shimmy — is one of the most exciting phenomena of vehicle dynamics. We give a brief description of a low degree of freedom rig of elastic tyre that was constructed for laboratory measurements. A full report is given on the experimental investigation of this rig from the identification of system parameters to the validation of stability boundaries and vibration frequencies of shimmy motion. The experimental results confirm the validity of those tyre models that include delay effects. A peculiar quasi-periodic oscillation detected during the experiments is explained by numerical simulations of the nonlinear time-delayed mathematical model.
Estimating Damping Parameters in Multi-Degree-of-Freedom Vibration Systems by Balancing Energy
Authors: Feeny B. F.
Published: May 2009

A method of estimating damping for multi-degree-of-freedom vibration systems is outlined. The method involves a balance of dissipated and supplied energies over a cycle of periodic vibration. The power is formulated as the inner product between velocity and force terms, and integrated over a cycle. Conservative terms (mass and stiffness) drop out of the formulation. If the displacement response and the input are measured, the damping coefficients can be estimated without knowledge of the mass and stiffness, which can be nonlinear. For large order systems, the identification equations are obtained after a modal reduction based on proper orthogonal decomposition. The method can be applied with a harmonic motion assumption, or by integrating more complicated responses for one period. The method is illustrated with a four degree-of-freedom system, and a string, both with linear and quadratic damping.
Dynamic Modeling and Experimental Testing of a Piano Action Mechanism With a Flexible Hammer Shank
Authors: Izadbakhsh Adel , McPhee John , Birkett Stephen
Published: May 2009

The piano action is the mechanism that transforms the finger force applied to a key into a motion of a hammer that strikes a piano string. This paper presents a state-of-the-art model of a grand piano action, which is based on the five main components of the action mechanism (key, whippen, jack, repetition lever, and hammer). Even though Askenfelt and Jansson [1] detected some flexibility for the hammer shank in their experiments, all previous piano models have assumed the hammers to be rigid bodies. In this paper, we have accounted for the hammer shank flexibility using a Rayleigh beam model. It turns out that the flexibility of the hammer shank does not significantly affect the rotation of the other parts of the piano mechanism, compared with the case that the hammer shank has been modeled as a rigid part. However, the flexibility of the hammer shank changes the impact velocity of the hammer head, and also causes a greater scuffing motion for the hammer head during the contact with the string. To validate the theoretical results, experimental measurements were taken by two strain gauges mounted on the hammer shank, and by optical encoders at three of the joints.
Natural Coordinates for Teaching Multibody Systems With Matlab
Authors: Garci´a de Jalo´n Javier , Shimizu Nobuyuki , Go´mez David
Published: May 2009

This paper deals with teaching kinematic and dynamic analysis of 3-D multibody systems in a context of courses with severe time constraints and the objective of attaining practical abilities. This high course efficiency is intended by the use of a simple theoretical approach (the natural or fully Cartesian coordinates) and a high level programming language (the function rich and easy to learn development tool Matlab. The theoretical prerequisites for such a course can be kept to a minimum. This approach would allow the introduction of some lessons on multibody systems inside more general courses on machine dynamics. It can also be useful for short courses addressed to engineers in industry and for numerical analysis courses addressed to mechanical engineering students that are interested in practical applications of these numerical methods. In this paper the achievable theory level will be presented in detail by means of a practical but non trivial example: a closed-chain 3-D robot. Natural coordinates and Matlab are also a good starting point to present more advanced techniques such as numerical integration methods for ODEs and DAEs, or the not very well known automatic differentiation techniques. The latter is considered as a more advanced example in this paper.
A Sequential Linear Programming Coordination Algorithm for Analytical Target Cascading
Authors: Han Jeongwoo , Papalambros Panos
Published: May 2009

Decomposition-based strategies, such as analytical target cascading (ATC), are often employed in design optimization of complex systems. Achieving convergence and computational efficiency in the coordination strategy that solves the partitioned problem is a key challenge. A new convergent strategy is proposed for ATC, which coordinates the interactions among subproblems using sequential lineralizations. Linearity of subproblems is maintained using L∞ norms to measure deviations between targets and responses. A subproblem suspension strategy is used to temporarily suspend inclusion of subproblems that do not need significant redesign, based on trust region and target value step size. The proposed strategy is intended for use in optimization problems where sequential linearizations are typically effective, such as problems with extensive monotonicities, large number of constraints relative to variables, and propagation of probabilities with normal distributions. Experiments with test problems show that, relative to standard ATC coordination, the number of subproblem evaluations is reduced considerably while maintaining accuracy.
Wavelet Coefficient Characteristics During Rotor/Auxiliary Bearing Contact in Active Magnetic Bearing Systems
Authors: Cade Iain S. , Keogh Patrick S. , Sahinkaya M. Necip , Burrows Clifford R.
Published: May 2009

Auxiliary bearings are present in active magnetic bearing systems to prevent rotor/stator contact. If rotor/bearing contact occurs, significant impact forces may arise. Furthermore, linear control strategies may become ineffective due to the non-linear dynamics introduced by the auxiliary bearing. Rotor/auxiliary bearing contact is therefore an important consideration for the continued safe operation of an active magnetic bearing system. This work utilizes the localized nature of wavelets coefficients in characterising rotor/bearing contact responses. An experimental approach is adopted using a flexible rotor/active magnetic bearing test rig. Different disturbances resulting in periodic rotor contact and rotor/bearing rub were applied using a single active magnetic bearing. Rotor displacements were measured and the radial component and associated wavelet coefficients identified from off-line data processing. Variations of the wavelet coefficients characteristics corresponding to the periodic contact and rotor/bearing rub are assessed. The choice of mother wavelet is seen to have only a small effect on wavelet coefficient values. Wavelet analysis is shown as a feasible method for identifying time-frequency characteristics of rotor/bearing contact.
Improving the Performance of Time-Triggered Embedded Systems by Means of a Scheduler Agent
Authors: Gendy Ayman K. , Dong Lei , Pont Michael J.
Published: May 2009

Knowledge of task execution time is a key requirement when determining the most appropriate scheduler algorithm (and scheduler parameters) for use with embedded systems. Unfortunately, determining task execution times (ETs) can be a challenging process. This paper introduces a novel system architecture which is based on two components (i) the main processor (MP) platform, containing the time-triggered (co-operative) scheduler and task code, and (ii) a second processor, executing a “scheduler agent” (SA). In the experiments described in this paper, the MP contains an instrumented scheduler and, during a “tuning” phase, the SA measures — on line — the ET of each task as it runs. The measured values are then used to fine tune the task schedule in an attempt to ensure that (i) all task constraints — such as deadline and jitter — are met (ii) power consumption is reduced. After the tuning phase is completed the SA continues to monitor the MP and can take appropriate action in case of errors. In the paper, the effectiveness of the proposed architecture is demonstrated empirically by applying it to a set of tasks that represent a typical embedded control system.
Towards a Reference Ontology for Functional Knowledge Interoperability
Authors: Kitamura Yoshinobu , Takafuji Sunao , Mizoguchi Riichiro
Published: May 2009

Functionality is one of the key aspects of artifact models for design. A function of a device, however, can be captured in different ways in different domains or by different model-authors. Much research on functions has been conducted in the areas of engineering design, functional representation and philosophy, although there are several definitions and notions of functions. We view conceptualization of function is multiplicative in nature: different functions can be captured simultaneously from an objective behavior of an artifact under different teleological contexts of users/designers, or from different viewpoints (perspectives) of a model-author. Such differences become problematic for sharing functional knowledge among engineers. In this article, we attempt to clarify the differences of such perspectives for capturing functions on the basis of the ontological engineering. On the basis of a generalized model of the standard input-output model in the well-known systematic design methodology, we show descriptive categorization of some upper-level types (classes) of functions with references to some definitions of functions in the literature. Such upper-level ontological categories of functions are intended to be used as a reference ontology for functional knowledge interoperability. One of the two usages here is to convert functional models between different functional taxonomies. A functional term in a taxonomy is (ideally) categorized into a generic type defined in the reference ontology. It is widely recognized in the literature that such an upper-level ontology helps automatic “mapping discovery” which is to find similarities between two ontologies and determine which concepts represent similar notion. The reference ontology of function might have such an effect. Another usage of the reference ontology is to integrate fault knowledge into functional knowledge and automatic transformation of FMEA sheets. The designer can describe an integrated model of both functional knowledge and fault knowledge. Based on ontology mappings, automatic transformations of FMEA sheets can be realized. In this article, we discuss the detail of the definitions of the upper-level categories of functions ontologically. Then, we give an overview of usages and effects of the upper-level categories as a reference ontology for functional knowledge interoperability.
Representing Historically Based Component-Function Relationships Through Design Templates
Authors: Abbott Daniel R. , Grantham Lough Katie
Published: May 2009

Functional analysis of systems is a common engineering application during different stages of design. Conceptual designers as well as post-development designers use the process to gather useful information about the system that is under consideration. The functional basis and component taxonomy are collective approaches to describe these systems in unique languages. Since many designers naturally think in terms of physical components, it is more difficult for them to grasp fundamental concepts necessary to functionally model a system properly. A new design instrument, component functional templates, has been developed as a means to link the functional basis and component taxonomy together in one coherent visual form that can be used by novice designers as an invaluable skill-building tool. Principal components analysis (PCA) is used to extract historical data from many consumer products whose design information has been stored in an online repository produced by the UMR Design Engineering Lab. This paper presents the approach and derivation of the templates, along with valid examples of template groupings that result from the analysis. An application of the templates is presented in a case study on the drive train of a bicycle where the templates prove to sufficiently begin the modeling process and provide room for unique manipulation that accurately describes functional requirements of the subsystem.
The Effect of Surface Waviness and Number of Rolling Elements on the Dynamic Behavior of a Rotor-Bearing System
Authors: Harsha S. P. , Nataraj C.
Published: May 2009

In the paper, the effects of the number of rolling elements and wave number of surface waviness on the nonlinear dynamic analysis of a rotor-bearing system has been studied. In the analytical formulation, the contacts between rolling elements and races are considered as nonlinear springs, whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The results are presented in the form of Fast Fourier Transformations (FFT) and Poincare´ maps, which show that the vibration characteristics of the rotor and its bearings change when the bearings operate in different regions of their nonlinear load deflection characteristics. The appearance of regions of periodic, sub-harmonic and chaotic behavior has been observed to be strongly dependent on number of rolling elements.
The Effect of Team Interaction Activity Based on Creativity Mode Self-Awareness for Team Based Conceptual Design Project
Authors: Kim Myung Sook , Kim Yong Se
Published: May 2009

This study analyzed the effect of team activities to promote team creativity and explored team interaction from the perspective of personal creativity modes. Freshman engineering students participated in the experiment. Teams in experimental group had an exercise of team activity immediately following self-awareness activity for their creativity mode. After team activity, team performances in conceptual design task were evaluated using Creative Product Semantic Scale (CPSS) composed of novelty and resolution categories. The results indicated that team performances of experimental group were significantly higher in CPSS evaluation, specifically in resolution, than those of control group. Also, team interaction of a diverse team and a uniform team from experimental group were analyzed using Interaction Process Analysis. The team interaction analysis showed that team members in diverse team represented very different team interaction patterns among team members, while team members in uniformed team demonstrated very similar patterns. These findings confirm that self-awareness of personal creativity mode help to enhance team creativity and that team interaction reflects some patterns according to personal characteristics.
Elasto-Viscoplastic Dispersive Waves in Silicon Wafers
Authors: Liu Li , Suh C. Steve
Published: May 2009

This paper provides the required knowledge base for establishing Laser Induced Stress Wave Thermometry (LISWT) as a viable alternative to current infrared technologies for temperature measurement up to 1000°C with ±1°C resolution. A stress wave propagation model having a complex, temperature-dependent elasto-viscoplastic constitutive law is developed. Investigated results show that wave group velocity is a nonlinear function of temperature. Nonlinearity becomes more prominent at high temperatures and low frequencies. As such, for LISWT to achieve better thermal resolution at high temperatures, low frequency components of the induced stress wave should be exploited. The results also show that the influence of temperature on attenuation is relatively small. It is not recommended to use attenuation for resolving temperature variation as small as several degrees Celsius. In addition to temperature, geometry also is found to have an impact on wave dispersion and attenuation. The influence of thickness on wave velocity is significant, thus suggesting that for LISWT to achieve high temperature resolution, wafer thickness must be accurately calibrated in order to eliminate all possible errors introduced by thickness variation.
Linear Chain of Coupled Fractional Oscillators: Response Dynamics and Its Continuum Limit
Authors: Achar B. N. Narahari , Prozny Tanya , Hanneken John W.
Published: May 2009

The standard model of a chain of simple harmonic oscillators of Condensed Matter Physics is generalized to a model of linear chain of coupled fractional oscillators in fractional dynamics. The set of integral equations of motion pertaining to the chain of harmonic oscillators is generalized by taking the integrals to be of arbitrary order according to the methods of fractional calculus to yield the equations of motion of a chain of coupled fractional oscillators. The solution is obtained by using Laplace transforms. The continuum limit of the equations is shown to yield the fractional diffusion-wave equation in one dimension. The solution and numerical application of the set of equations and the continuum limit there of are discussed.
A New Approximation Approach in Routines Implementation of Non Integer Order PID Controller
Authors: Caponetto Riccardo , Brunno Francesco
Published: May 2009

In the paper a numerical approach to implement a fractional PID controller and some optimization routines are given. The novelty of the proposed algorithms consists in a new procedure to implement differentiation and integration with a limited samples storing. The introduced strategy will let to implement a fractional PID on microcontroller with limited storing capacity.
System Identification Techniques for Mixed Responses Using the Proper Orthogonal Decomposition
Authors: Allison Timothy C. , Miller A. Keith , Inman Daniel J.
Published: May 2009

The Proper Orthogonal Decomposition (POD) is a method that may be applied to linear and nonlinear structures for extracting important information from a measured structural response. The POD is often applied for model reduction of linear and nonlinear systems and recently in system identification. Although methods have previously been developed to identify reduced-order predictive models for simple linear and nonlinear structures using the POD of a measured structural response, the application of these methods has been limited to cases where the excitation is either an initial condition or an applied load but not a combination of the two. This paper presents a method for combining the POD-based identification techniques for strictly free or strictly forced systems to identify predictive models for a system when only mixed response data are available, i.e. response data resulting from initial conditions and loads that are applied together. This method extends the applicability of POD-based identification techniques to operational data acquired outside of a controlled laboratory setting. The method is applied to finite element models of simple linear and nonlinear beams and is shown to identify an accurate predictive model for each beam when compared with results obtained by the finite element method.
A Virtual Harp With Physical String Vibrations in an Augmented Reality Environment
Authors: Taylor Tanasha , Smith Shana , Suh David
Published: May 2009

This research provides a prototype of a computer-generated harp, using physical string vibrations with haptic feedback in an augmented reality environment. The individuals, immersed in an augmented reality environment using a head mounted display, play the virtual harp with the Phantom Omni haptic device receiving realistic interactions from the strings of the harp. Most previous musical instruments research only provides feedback in the form of visual and audio cues, but not haptic cues. The proposed project is designed to provide individuals with all three forms of cues for interacting with a computer-generated harp. This computer-generated harp is modeled as a realistic harp and includes physics for string vibrations to provide the individuals a traditional instrument-like interaction. This prototype will be applied towards interactive musical experiences and development of skills during music therapy for individuals with disabilities.
Measurement of Headlight Form Preference Using a Choice Based Conjoint Analysis
Authors: Swamy Surya , Orsborn Seth , Michalek Jeremy , Cagan Jonathan
Published: May 2009

The measurement and understanding of user aesthetic preference for form is a critical element to the product development process and has been a design challenge for many years. In this article preference is represented in a utility function directly related to the engineering representation for the automobile headlight. A method is proposed to solicit and measure customer preferences for shape of the automobile headlight using a choice task on a main-effects conjoint survey design to discover and design the most preferred shape.
Adaptive Fuzzy Segmentation of Tumors in Three-Dimensional Computed Tomography (CT) Image Data
Authors: Foo Jung Leng , Miyano Go , Lobe Thom , Winer Eliot
Published: May 2009

The continuing advancement of computed tomography (CT) technology has improved the analysis and visualization of tumor data. As imaging technology continues to accommodate the need for high quality medical image data, this encourages the research for more efficient ways of extracting crucial information from these vast amounts of data. A new segmentation method using a fuzzy rule based system to segment tumors in a three-dimensional CT data has been developed. To initialize the segmentation process, the user selects the region of interest (ROI) within the tumor in the first image of the CT study set. Using the ROI’s spatial and intensity properties, fuzzy inputs are generated for use in the fuzzy inference system. From a set of predefined fuzzy rules, the system generates a defuzzified output for every pixel in terms of similarity to the object. Pixels with the highest similarity values are selected to be the tumor. This process is repeated for every subsequent slice in the CT set, and the segmented region from the previous slice is used as the ROI for the current slice. This creates a propagation of information from the previous slices, to be used to segment the current slice. The membership functions used during the fuzzification and defuzzification processes are adaptive to the changes in the size and pixel intensities of the current ROI. The proposed method is highly customizable to suit different needs of a user, requiring information from only a single two-dimensional image. Implementing the fuzzy segmentation on two distinct CT sets, the fuzzy segmentation algorithm was able to successfully extract the tumor from the CT image data. Based on the results statistics, the developed segmentation technique is approximately 96% accurate when compared to the results of manual segmentations performed.
A New Nanomechanical Cantilever Sensing Paradigm Using Piezoelectric Boron Nitride Nanotube-Based Actuation
Authors: Hosseini Mahmoud Reza , Jalili Nader
Published: May 2009

Nanomechanical Cantilever Sensors (NMCS) have recently attracted a widespread attention for use in different nano- and micro-size applications such as studying the nanoscale surface topography by scanning probe microscopy and atomic force microscopy (AFM). In newer AFM systems, a sharp probe is placed at the tip of the microcantilever and a piezoelectric patch actuator deposited on the cantilever surface produces the movements of the probe above the examined surface. Similar system can be also utilized for mass sensing purposes by adding an unknown mass to the tip and measuring the beam deflection and the amount of shift in the resonance frequency that is caused by the addition of the tip mass. This sensing paradigm finds many applications in medical and biological fields such as DNA strand and bacteria weight measurement. However, one of the major issues in all piezoelectrically-actuated microcantilevers is the low actuation energy of the piezoelectric patch. Most of the current and widely used piezoelectric materials possess low mechanical characteristics such as low Young’s modulus of elasticity, low yield strength and most importantly incompatibility with most biological species and environment. It has been shown that both carbon and boron nitride nanotubes (CNT and BNNT) possess outstanding mechanical, chemical and electrical properties with acceptable piezoelectricity which make them suitable for microcantilever actuation applications. In this paper, a multi-physics multi-scale model is proposed in which the actuation of microcantilevers is produced by two sets of nanotube layers. Through extensive simulations, BNNTs were chosen to be used as the actuators because of their enhanced piezoelectric characteristics compared to CNTs. The modeling framework proposed here is used to investigate the effects of deposited tip mass with different weights on frequency response and resonance frequency of the microcantilever beam. These microbeams are made of aluminum or titanium materials and the results are compared with each other.
Numerical Simulations of Two-Phase Turbulent Combustion in Spray Burners
Authors: Li Zhaorui , Yaldizli Murat , Jaberi Farhad A.
Published: May 2009

The complex interactions among turbulence, combustion and spray in liquid-fuel burners are modeled and simulated via a new two-phase Lagrangian-Eulerian-Lagrangian large eddy simulation (LES) methodology. In this methodology, the spray is modeled with a Lagrangian mathematical/computational method which allows two-way mass, momentum and energy coupling between phases. The subgrid gas-liquid combustion is based on the two-phase filtered mass density function (FMDF) that has several advantages over “conventional” two-phase combustion models. The LES/FMDF is employed in conjunction with non-equilibrium reaction and droplet models. Simulations of turbulent combustion in a spray-controlled double-swirl burner are conducted via LES/FMDF. The generated results are used for better understanding of spray combustion in realistic turbulent flow configurations. The effects of spray angle, mass loading ratio, fuel type, droplet size distribution, wall and inflow/outflow conditions on the flow and combustion are investigated. The LES/FMDF predictions are shown to be consistent with the experimental results.
On the Length of Dynamical System Control Programs
Authors: Bonsignorio Fabio P.
Published: May 2009

Examples from robotics research on bipedal walkers have shown that complex control programs integrating an explicit multibody model into the control program can be outperformed by very simple reinforced learning schemas applied to a ‘fit’ mechanical structure. This seems to show that in robotic and, in general, controlled system there are relations between the information metrics of the control programs and the system dynamics. The relations shown in this paper could help to understand the relations involved by the phase space ‘footprint’ of dynamical systems and the complexity, in the information theory sense, of their control programs, and possibly to ease, giving a quantitative guidance, the development of new more ‘intelligent’ artefacts. This is relevant to control theory and practice as the control of bipedal walkers have proven to be eased in term of complexity of control programs by the so called ‘passive walker’ approaches which leverage of the intrinsic dynamic characteristics of the walker systems. It is relevant to AI research, too, where embodiment behavior based and emergent controls are widely used in the practice of robotics, but still miss a comprehensive quantitative analysis framework. Bipedal walkers are examples of non linear mechanical dynamical systems. The equation derived here could be regarded as an hint of a general connection between control and information theory, so far not completely investigated.
Balancing Operational and Strategic Impacts on Information Management
Authors: Malvius Diana , Bergsjo¨ Dag , Molneryd Sara
Published: May 2009

Strategies for successful information management that supports multidisciplinary systems engineering are reported on. Inter-disciplinary and inter-lifecycle integration are considered as prerequisites to establish efficient information management. Top and middle management, and designer perspectives on integrated information management have been studied in an interview study within electrical and electronics, and software R&D departments in the automotive industry. Identified misalignments in needs, expected benefits and goals for information management between different perspectives are described. Ways to achieve synergies and conflicts with operational and strategic impacts on information management are discussed in the paper.
A Template-Based Approach for Multilevel Blast Resistant Panel Design
Authors: Muchnick Hannah , Allen Janet K. , McDowell David L. , Mistree Farrokh
Published: May 2009

Multilevel design is a subset of engineering design in which design problems are defined and analyzed at various levels of model complexity or resolution. Due to the potential for propagated uncertainty in a multilevel design process, design goals for maximizing system robustness to uncertainty in noise and control factors are included in the Blast resistant panels (BRP) design process. Blast resistant panels (BRPs) are sandwich structures consisting of two solid panels surrounding a honeycomb core. Under impulse loading, BRPs experience less deflection than similarly loaded solid panels of equal mass due to core crushing. In order to manage complexity in BRP concurrent product and materials design, a multilevel design approach is proposed. Additionally, in order to collect and store BRP design information in a modular and reusable format, a template-based design approach is implemented in BRP multilevel design. In this paper, a generic multilevel design template based on existing design methods (the compromise Decision Support Problem and the Inductive Design Exploration Method) is presented. The multilevel design template is then particularized and applied to BRP preliminary design, highlighting the advantages of a templatebased approach to multilevel design.
Algorithms for Generating Adaptive Projection Patterns for 3-D Shape Measurement
Authors: Peng Tao , Gupta Satyandra K.
Published: May 2009

Point cloud acquisition using digital fringe projection (PCCDFP) is a non-contact technique for acquiring dense point clouds to represent the 3-D shapes of objects. Most existing PCCDFP systems use projection patterns consisting of straight fringes with fixed fringe pitches. In certain situations, such patterns do not give the best results. In our earlier work, we have shown that in some situations, patterns that use curved fringes with spatial pitch variation can significantly improve the process of constructing point clouds. This paper describes algorithms for automatically generating adaptive projection patterns that use curved fringes with spatial pitch variation to provide improved results for an object being measured. In addition, we also describe the supporting algorithms that are needed for utilizing adaptive projection patterns. Both simulation and physical experiments show that, adaptive patterns are able to achieve improved performance, in terms of measurement accuracy and coverage, than fixed-pitch straight fringe patterns.
Simultaneous Hierarchical and Multi-Level Optimization for Material Characterization and Design of Experiments
Authors: Michopoulos John G. , Furukawa Tomonari , Hermanson John C. , Lambrakos Samuel G.
Published: May 2009

A hierarchical algorithmic and computational scheme based on a staggered design optimization approach is presented. This scheme is structured for unique characterization of many continuum systems and their associated datasets of experimental measurements related to their response characteristics. This methodology achieves both online (real-time) and offline design of optimum experiments required for characterization of the material system under consideration, while also achieving a constitutive characterization of the system. The approach assumes that mechatronic systems are available for exposing specimens to multidimensional loading paths and for the acquisition of data associated with stimulus and response behavior. Material characterization is achieved by minimizing the difference between system responses that are measured experimentally and predicted based on model representation. The performance metrics of the material characterization process are used to construct objective functions for the design of experiments at a higher-level optimization. The distinguishability and uniqueness of solutions that characterize the system are used as two of many possible measures adopted for construction of objective functions required for design of experiments. Finally, a demonstration of the methodology is presented that considers the best loading path of a two degree-of-freedom loading machine for characterization of the linear elastic constitutive response of anisotropic materials.