bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Active Patterns for the Conceptual Design of Self-Optimizing Systems Exemplified by an Air Gap Adjustment System
Authors: Gausemeier Ju¨rgen , Dangelmaier Wilhelm , Zimmer Detmar , Schmidt Alexander , Frank Ursula , Klo¨pper Benjamin
Published: May 2009

The conceivable evolution of information technology will enable mechatronic systems with inherent partial intelligence. We call this kind of systems self-optimizing. Self-optimizing systems are able to react autonomously and flexible to changing environmental conditions. They are capable of learning and optimizing their behavior at run-time. This paper presents the paradigm of self-optimization and shows how to develop self-optimizing systems. Focus is the conceptual design phase. The result of this phase is the principle solution. In this paper at first we explain how to describe the principle solution in a domain-spanning way. This is of high importance because a holistic description of the principle solution constitutes the basis for the communication and cooperation between the engineers from different domains who are engaged in developing a self-optimizing system. At second we introduce solution patterns for developing principle solutions. Solution patterns enable the reuse of design knowledge so that the development process will be more effective. This paper focuses on solution patterns including self-optimizing solutions. How the methods work we explain by the complex magnetic linear drive of a shuttle.
A Methodology for Obtaining Optimum Gear Tooth Micro-Topographies for Noise and Stress Minimization Over a Broad Operating Torque Range
Authors: Harianto Jonny , Houser Donald R.
Published: May 2009

This paper presents a method of evaluating the effect of micro-geometric or micro-topographic variation on various gear performance parameters, such as noise excitations, gear contact and root stresses, film thickness, and surface temperature under loaded conditions. Micro geometries that are considered are profile crown, profile slope, lead crown, lead slope, and bias modifications variations. Various combinations of these micro geometries are considered in analytical simulations in which respective gear design metrics are evaluated based on the calculated load distributions. This paper will provide a walk through analysis for a helical gear design in order to describe the procedure.
Dynamic Optimization of Spur Gears
Authors: Faggioni M. , Pellicano F. , Andrisano A. , Bertacchi G.
Published: May 2009

This paper presents a global optimization method able to find gear profile modifications that minimize vibrations. A non linear dynamic model is used to study the vibrational behavior; the dynamic model is validated using data available in literature. The optimization method takes into account the influence of torque levels both on the static and the dynamic response. Therefore, two different objective functions are considered; the first one is based on static analysis and the second one is based on the dynamic behavior of a lumped mass system. The procedure can find the optimal profile modification that reduce the vibrations over a wide range of operating conditions. In order to reduce the computational cost, a Random-Simplex optimization algorithm is developed; the optimum reliability is also estimated using a Monte Carlo simulation. The approach shows good performances both for the computational efficiency and the reliability of results.
A Single Piezoelectric Trimorph Driven Bi-Directional Linear Ultrasonic Motor
Authors: Wu Tung-Li , Yang Chen-Hui , Chang Shuo-Hung
Published: May 2009

The design of using a single piezoelectric (PZT) trimorph actuator ultrasonically to drive a slider for two directional motions is reported. The working principle is the use of the resonant vibration induced force provided by the PZT trimorph driven at the specific frequency. In contact with a slider, the trimorph’s force overcomes the static friction of the slider and pushes the slider moving in one direction. The backward motion of the slider is achieved similarly by the different vibration mode of the PZT trimorph operated at the different resonant frequency. The merit of this work is the design of the rectangular PZT trimorph and its modes of vibration. The 3 mm by 9 mm rectangular trimorph was made of a 50 microns thick copper layer laminated with a 175 microns thick PZT layer on each face. As for ultrasonic motor operation, only one long edge of the trimorph was clamped. When the PZT layers were driven electrically at its resonant frequency and at the right phase, the PZT’s in-plane extensional vibration will turn into bending vibration. With extensive modal analysis in the Finite Element modeling, the 3:1 ratio of the length to width of the trimorph was found for the best performances. Both resonant frequencies and associated vibration modes were all identified. The performance of the prototype was experimentally evaluated by using laser interferometer and spectrum analyzer. Under 10 Vpp and 0.5 N preload, the measurement results show that the motor achieved the velocity of 200 mm/s and generated force of 0.1 N. If we divided the generated force and the slider velocity by the motor volume, the ultrasonic motor achieved the specific force of 3,282,447 3N/m3 and the specific velocity of 4,106,280 1/m2s, respectively. Comparing with the published data, the specific velocity in this study is 100 times larger. The results in this work are suitable for applications in auto-focusing and zooming lens in cellular phone camera.
Synthesis of Dynamical Structure of the Hydraulic Breaker With a Vibration-Free Handle
Authors: Sokolov I. J. , Babitsky V. I. , Halliwell N. A.
Published: May 2009

An approach to the synthesis of a dynamical structure of the hand-held percussion machine with a vibration-free handle is presented. This is based on the consideration of the optimal dynamic conversion of energy in hand-held percussion machines founded as a solution of the equivalent problem of the optimal control [1]. For an accomplishment of the optimal regime a proper dynamic structure of the percussion machine as a multi-body vibro-impact system with one body (casing/handle) being free of vibration is found and investigated. Computer simulations and initial experiments validated the new approach. The main feature of the proposed design realising the synthesised structure is the use of a mechanism with zero differential stiffness. A hydro-pneumatic unit with zero stiffness was developed and tested. Theoretical recommendations have been applied to a commercial hydraulic breaker. A proper modification of the design and effective use of existing hydraulic power source provided a significant improvement in performance.
Robust Control of a Laboratory Hydraulic Canal by Using a Fractional PI Controller
Authors: Sa´nchez Rodri´guez Luis , Feliu Batlle Vicente , Rivas Pe´rez Rau´l , Rui´z Torija Miguel A´ngel
Published: May 2009

A fractional order control strategy has been implemented in an automated laboratory hydraulic canal characterized to present time-varying dynamical parameters. A method for tuning a fractional order PI controller that makes the hydraulic canal control system robust to process parameters variations has been proposed too. Experiments have been carried out in our laboratory hydraulic canal, and the fractional controller has been implemented in an industrial SCADA (Supervisory Control And Data Acquisition) control and supervision system. The comparison between the response of our fractional PI controller and the standard PI controller proved the effectiveness of the proposed fractional order control strategy in terms of performance and robustness.
An Advanced Numerical Model for Assessing 3-D Wind Fields
Authors: Pepper Darrell W. , Wang Xiuling
Published: May 2009

An h-adaptive mass consistent finite element model (FEM) is developed for constructing 3-D wind fields over irregular terrain. The h-adaptive FEM allows the element size to be changed dynamically according to local flow and topographic features. The mesh is refined and unrefined to satisfy preset error criteria. Localized high resolution wind fields can be constructed. The FEM model uses a variational method in an integral function that minimizes the variance of the difference between the observed and analyzed variable. Simulation results are presented for constructing 3-D wind fields for two regions in Nevada. The method appears promising for accurately depicting large scale wind fields, especially where high resolution is needed to capture rapidly changing flows associated with local topographic features.
Combining Geometric Constraints With Physics Modeling for Virtual Assembly Using SHARP
Authors: Seth Abhishek , Vance Judy M. , Oliver James H.
Published: May 2009

This research combines physics-based and constraint-based approaches for virtual assembly simulations where geometric constraints are created or deleted within the virtual environment at runtime. In addition, this research provides a solution to low clearance assembly by utilizing B-Rep data representation of complex CAD models for accurate collision/physics results. These techniques are demonstrated in the SHARP software (System for Haptic Assembly and Realistic Prototyping). Combining physics-based and constraint-based techniques and operating on accurate B-rep data, SHARP can now assemble parts with 0.001% clearance and can accurately detect collision responses with 0.0001mm accuracy. Case studies are presented which can be used to identify the suitable combination of methods capable of best simulating intricate interactions and environment behavior during manual assembly.
Optimal and Robust Control of Enhanced Active Constrained Layer Treatment With Passive Shunt Circuit Under Consideration of Temperature Effect
Authors: Tsai Meng-Shiun , Hwang Tai-Yen , Nien Hao-Wei
Published: May 2009

The optimal and robust H∞ control designs for the enhanced active constrained layer treatment (EACL) and the EACL system with passive shunt circuits (EACL-Shunt) are analyzed in this paper. The GHM method is adopted to model the dynamic behavior of the viscoleastic layer in EACL which is highly dependent on temperature. The system variations due to temperature changes are modeled as system uncertainties. Root locus technique is applied to analyze the stability problem when temperature changes. It is shown that the added shunt circuit on the EACL can indeed improve system robustness (reduced uncertainties).
Nonlinear Dynamics of a Four-Wheel Vehicle With Lateral Load Transfer Effects
Authors: Nguyen Vincent , Schultz Gregory , Balachandran Balakumar
Published: May 2009

Two-dimensional, in-plane maneuvers are investigated by using a four-wheel vehicle model. Individual tire slip angles and loading conditions are considered. Lateral load transfer and roll moment distribution effects are included in the two-dimensional analysis by applying instantaneous roll angle propagation. Numerical simulations are performed for a heavily loaded vehicle. Bifurcations of equilibria are presented with respect to vehicle velocity and roll stiffness. This effort provides a framework for vehicle handling assessment in terms of nonlinear regions of performance, transient behavior, and roll moment distribution.
Analysis of Tool Accessibility in Fixture Setup Planning
Authors: Kang Xiumei , Peng Qingjin
Published: May 2009

Tool accessibility is a critical issue for generating a complete fixture setup plan to reduce production setup time. Previous fixture design systems rarely consider the assembly tool accessibility. Current methods of assembly tool accessibility analysis mainly depend on simulation-based or user-interactive approaches which rely on users’ judgment. This paper presents a new approach to tool accessibility analysis for fixture setup planning. The fixture workspace around a tool is represented by a newly defined global accessibility sphere with depth of a truncated half-line. The assembly tools are modeled as five articulated parts to fully describe the tool characteristics. Accessibility analysis is executed to verify assembly tools’ feasibility applied on a fastener. In particular, both tool motion and tool placement constraints during tool applications are integrated into the tool geometric reasoning. The example demonstrates the fast computing speed and intuitive simulation of several assembly tools in fixture setup planning.
Optimal Partitioning and Coordination Decisions in Decomposition-Based Design Optimization
Authors: Allison James T. , Kokkolaras Michael , Papalambros Panos Y.
Published: May 2009

Solution of complex system design problems using distributed, decomposition-based optimization methods requires determination of appropriate problem partitioning and coordination strategies. Previous optimal partitioning techniques have not addressed the coordination issue explicitly. This article presents a formal approach to simultaneous partitioning and coordination strategy decisions that can provide insights on whether a decomposition-based method will be effective for a given problem. Pareto-optimal solutions are generated to quantify tradeoffs between the sizes of subproblems and coordination problems, as measures of the computational costs resulting from different partitioning-coordination strategies. Promising preliminary results with small test problems are presented. The approach is illustrated on an electric water pump design problem.
Collective Dynamics of Kinesin-1 Motor Proteins Transporting a Common Load
Authors: Hendricks Adam G. , Epureanu Bogdan I. , Meyho¨fer Edgar
Published: May 2009

Kinesin-1 is a motor protein essential to intracellular transport that converts the energy from ATP hydrolysis to directed movement along microtubules. Experimental and theoretical characterization of kinesin-1 has focused on single-molecule experiments. These experiments show that one motor is capable of transporting a cargo at speeds of about 1 μm/sec and maintaining contact with the microtubule for about 100 steps. In the cell, it is widely thought that several kinesin-1 motors cooperate to transport a cargo. Through a mechanistic model, we have extended the theoretical analysis of kinesin to describing transient and steady state behavior. A transient description is essential when studying collective behavior, as interaction between motors introduces time-varying loads. Herein, we interpret the kinesin motors as nonlinear, non-smooth oscillators and we employ metrics to characterize their cooperativity and to quantify their synchronization. These metrics are used to investigate the effect of the cargo linker stiffness, the load, and the difference in intrinsic velocity on the synchronization of two mechanically coupled motors.
Wavelet SDF-Reps: Solid Modeling With Volumetric Scans
Authors: Storti Duane , Ganter Mark A. , Ledoux William R. , Ching Randal P. , Hu Yangqiu Patrick , Haynor David
Published: May 2009

This paper describes a new formulation of solid modeling that addresses the issue of including parts whose geometry is determined from volumetric scans (CT, MRI, PET, etc.) along with parts whose geometry is designed by traditional computer-aided design (CAD) operations. Such issues arise frequently in the design of medical devices or prostheses where fit and/or interference between man-made artifacts and existing anatomy are essential considerations, but the modeling formulation presented is not limited to medical applications and can be applied to any parts whose volume can be actually or virtually scanned. Scanner data typically comprises a grid of intensity values and segmentation must be performed to determine the extent of the part. In current practice, the segmented scanner data is run through a polygonizer to obtain an approximate tessellation of the object’s surface. Even in the best case scenario where the triangles obtained form a closed surface that accurately approximates the surface of the scanned object, such triangulated models can be problematic due to excessive size. We present an alternative approach based on recent advances in segmentation with level set methods. The output of the level set computation is a grid of approximate values for the signed distance from each grid point to the nearest point on the surface of the scanned object. We propose interpolating the grid of signed distance values to obtain an implicit or function-based representation (f-rep) for the object, and we introduce appropriate wavelets to effectively perform the interpolation while also providing a number of other useful properties including data compression, inherently multi-scale modeling, and capabilities for skeletal-based modeling operations.
Optimal Nonholonomic Motion Planning of Space Robot System With Dual-Arms
Authors: Chen Li , Tang Xiaoteng
Published: May 2009

In this paper, the optimal nonholonomic motion planning of free-floating space robot system with dual-arms is discussed. Base on the linear and angular momentum conservations of the system, the system state equations for control design are established, so the nonholonomic motion planning objective of attitude control of space robot system is translated as the solution of a canonical nonlinear control problem. An optimal control scheme of the system proposed is studied, using radial basis function approximation; a numerical algorithm for computing approximate optimal control of the system proposed is developed. The optimal motion planning approach proposed above possesses the advantages that it can obtain the desired angles of the base’s attitude and arms’ joints only by controlling the arms’ joints motion. A planar free-floating space robot system with dual-arms is simulated to verify the proposed approach.
An Application of Relay Feedback to Mass Measurement Under Weightless Conditions
Authors: Mizuno Takeshi , Takeuchi Minoru , Ishino Yuji , Takasaki Masaya
Published: May 2009

Relay feedback was applied to measuring mass even under weightless conditions. A measurement object is driven by a force-output actuator. The motion of the object is controlled by a relay feedback system. The used relay element has dead zone and switches force acting on the object in relation to the position of the measurement object. The mass of the object is determined from the time interval measurement of the on-state and off-state periods. An apparatus was developed for experimental study. It uses a voice coil motor as an actuator, and a pair of photo interrupters for detecting the switching positions. The effects of system parameters on measurement accuracy were studied experimentally. Under the tuned conditions, the measurement errors were within 0.2[%]. Measurement on a base moving freely was also carried out.
A Learning Algorithm for Optimal Internal Combustion Engine Calibration in Real Time
Authors: Malikopoulos Andreas A. , Papalambros Panos Y. , Assanis Dennis N.
Published: May 2009

Advanced internal combustion engine technologies have increased the number of accessible variables of an engine and our ability to control them. The optimal values of these variables are designated during engine calibration by means of a static correlation between the controllable variables and the corresponding steady-state engine operating points. While the engine is running, these correlations are being interpolated to provide values of the controllable variables for each operating point. These values are controlled by the electronic control unit to achieve desirable engine performance, for example in fuel economy, pollutant emissions, and engine acceleration. The state-of-the-art engine calibration cannot guarantee continuously optimal engine operation for the entire operating domain, especially in transient cases encountered in driving styles of different drivers. This paper presents the theoretical basis and algorithmic implementation for allowing the engine to learn the optimal set values of accessible variables in real time while running a vehicle. Through this new approach, the engine progressively perceives the driver’s driving style and eventually learns to operate in a manner that optimizes specified performance indices. The effectiveness of the approach is demonstrated through simulation of a spark ignition engine, which learns to optimize fuel economy with respect to spark ignition timing, while it is running a vehicle.
Emotional Shape Generation System With Exchange of Others’ Viewpoints for Externalizing Customers’ Latent Sensitivity
Authors: Yanagisawa Hideyoshi , Murakami Tamotsu
Published: May 2009

The aesthetics of a product’s shape has become an important factor to increase the value of mature products. However, such emotional quality regarding the customer’s need is difficult to capture due to its subjectivity. To address this issue, we have previously proposed shape generation methods that help the customers to externalize their image of product aesthetics into a shape. The previous methods enable one to generate design samples that fit the customer’s conscious image of a product shape based on his/her fixed sensitivity. However, customers also have latent sensitivities of which they are not aware. In this paper, we propose a shape generation system that enables the user to exchange design solutions and viewpoints with others. The aim of sharing solutions is to evoke the latent sensitivities by showing the unexpected viewpoints of others. To generate design samples, we improve the previous system in which the users generate design samples based on favored features to which they pay attention. We conduct a shape generation experiment using the proposed system to verify the effectiveness of exchanging solutions and viewpoints with others. We compared the effectiveness of self-solutions, which are generated without the exchange, with co-solutions, which are generated with the exchange. The result suggests that the co-solutions are more likely to be effective as to their preference and unpredictable quality. We observed certain effective patterns in the design process: All co-solutions generated by referring to unpredicted topological shapes produced effective results. Using such shapes, the subjects are able to discover new viewpoints for the target design concept. The stated metaphorical viewpoints of others also help to introduce such new viewpoints.
Human and Machine Stick Balancing
Authors: Tajima Shigeru , Ohira Toru , Tonosaki Yukinori
Published: May 2009

We compared the similarities and differences in stick balancing for the human fingertip and that by a servo-controlled machine. The motion of the stick in both cases exhibited a swinging or hunting behavior, which appears to be related to feedback delay. However, human stick balancing appears also to be affected by psychological factors, such as attention, which are not present in machine control systems. We discuss how machine control systems compare with human stick balancing. We also discuss about the repulsive delayed random walk as a simplified model of the stick balancing.
Compliance Effect Consideration for Real-Time Multibody Vehicle Dynamics Using Quasi-Static Analysis
Authors: Kim Sung-Soo , Jeong Wan Hee , Kim Seonghoon
Published: May 2009

HILS (Hardware-in-the Loop Simulation) vehicle simulator is one of the most effective tools to develop control subsystems for the intelligent vehicles, since expensive vehicle field tests can be replaced with virtual tests in the HILS simulator. In the HILS simulator, the software vehicle dynamics model must be solved in real-time, and it must also reproduce the real vehicle motions. Compliance effects from suspension bush elements significantly influences the vehicle behavior. In order to include such compliance effects to the vehicle model, normally the spring-damper model of the bush elements is used. However, high stiffness of the bush elements hinders real-time simulations. Thus, it is necessary to have an efficient method to include compliance effects for the real-time multibody vehicle dynamics model. In this paper, compliance model for real-time multibody vehicle dynamics is proposed using quasi-static analysis. The multibody vehicle model without bush elements is used based on the subsystem synthesis method which provides real-time computation on the multibody vehicle model. Reaction forces are computed in the suspension subsystem. According to deformation from the quasi-static analysis using reaction forces and bush stiffness, suspension hardpoint locations and suspension linkage orientation are changed. To validate the proposed method, quarter car simulations and full car bump run simulations are carried out comparing with the ADAMS vehicle model with bush elements. CPU times are also measured to see the real-time capabilities of the proposed method.
Hybrid Approach to Modeling a Flexible Parallel Robot for Vibration Damping
Authors: Kroneis Jens , Liu Steven
Published: May 2009

In this paper a new method for derivation and verification of rigid and flexible body kinematic and dynamic models of complex parallel robots including crank mechanisms is presented. The rigid body kinematic model is based on standard frame transformations and involves holonomic constraints. Lagrange’s equations of the first type are used for the dynamic modeling of the rigid structure. Using Euler-Bernoulli beams and assumed modes method, a new concept for deriving flexible kinematics and dynamics is developed considering configuration-dependent end masses, called effective payloads. Furthermore a vibration analysis is accomplished and a vibration damping strategy for the parallel robot based on input shaping is described. Through the whole verification process MSC.ADAMS models and measurement data of the demonstrator SpiderMill are used.
Matching Geometric Shapes in 4D Space Incorporating Curvature Information
Authors: Song Y. , Vergeest J. S. M.
Published: May 2009

The Iterative Closest Point (ICP) algorithm and its variants are widely used in matching different patches of 3-Dimensional (3D) scanning data. In this paper, a 4-Dimensional (4D) based approach is proposed to improve the robustness of the ICP algorithm. Considering curvatures of the given geometries as an extra dimension, the existing ICP algorithm can be extended to 4D space. The reason of using this additional information is that it introduces an extra dimension of similarity in the shape matching algorithm, thus improves the effectiveness of the optimization process. Using a variant of the Laplacian smoothing tool, high frequency noise and interferences in the curvature domain are suppressed and the principal geometric features are addressed. By a 4D to 3D orthogonal projection, the matched geometries are projected back to 3D space, where the existing ICP algorithm in 3D is applied as a fine-tuning tool. Numerical implementations on several sets of scanning data demonstrate the robustness of the proposed method. The converging process and the speed of the propose method are investigated as well.
Joost J. Kalker (1933-2006): A Life in Rolling Contact
Authors: Schwab A. L. , Kalker-Kalkman C. M.
Published: May 2009

Joost Kalker, famous for his mathematical description of the wheel-rail contact, died on April 24, 2006 of heart failure, at the age of 72. Apart from a heart condition, which he developed earlier in life, he suffered the last ten years from Parkinson’s disease.
Analysis of Anti Vibratory Passive and Active Methods Applied to Complex Mechanical System
Authors: Lopez Ce´dric , Malburet Franc¸ois , Barraco Andre`
Published: May 2009

This paper studies problematic of a mechanical system composed of different coupled parts submitted to a high speed shock and proposes analysis of anti vibratory passive and active methods based on an experimental and theoretical coupled approach. After a shock, different parts of the system oscillate. If one of them is excited at a particular frequency, such as its proper frequency, important oscillations appear and can lead to the deterioration of the system by introducing important stresses. In this paper, we propose an analysis in order to understand this kind of problem and what we can do to avoid it. Firstly we discuss problematic and we expose the studied system. In a second time, we develop two approaches of modeling that allow us to understand the phenomenon by carrying out numerical simulations. Then cross checking of model is completed via experimental study on drop test bench. Passive minimization method of vibrations based on experimental and theoretical coupled approach is exposed. Finally a comparative analysis of different methods of control is presented.
Geometrical Robust Form Division
Authors: Dagman Andreas , So¨derberg Rikard
Published: May 2009

By combining a Computer Aided Industrial Design (CAID) tool with a Computer Aided Tolerancing (CAT) tool, concurrent work between two related, but in industry often separated, areas with correlated product design features is facilitated. This paper presents an analysis tool that allows the creation and evaluation of split-lines in design concepts with respect to geometrical robustness and aesthetics. The aim with the analysis tool is to create products that are insensitive to manufacturing variation with the industrial design intent preserved. Since the split-lines are clues to detecting variation in assembled products, as well as part of the design language and the characterization of the product, it is important to work with these issues concurrently. The platform concept has been increasingly adopted in companies which, in many cases, provide an inheritance of the locating schemes, thus affecting the geometrical robustness of the concept, between models and sometimes even brands. This means that the parts creating an assembled product need to be designed in such a way that they satisfy the locating scheme configuration to achieve a geometrically robust solution. The functionality of the analysis tool has been demonstrated on an automobile body.
Study of Component Mode Synthesis Methods in a Rotor-Stator Interaction Case
Authors: Batailly Alain , Legrand Mathias , Cartraud Patrice , Pierre Christophe , Lombard Jean-Pierre
Published: May 2009

The study of rotor-stator interactions between blade-tips and outer casings through direct contact in modern turbomachines is very time-consuming if the classical finite element method is used. In order to improve the knowledge over these interaction phenomena, faster methods have to be applied. The construction of reduced-order models using component mode synthesis methods generally allows for dramatic increase in computational efficiency. Two of these methods, namely a fixed interface method and a free interface methods are considered in an original manner to reduce the size of a realistic two-dimensional model. They are then compared in a very specific contact case-study. The equations of motion are solved using an explicit time integration scheme with the Lagrange multiplier method where friction is accounted for. The primary goal of the present study is to investigate the general behavior of such approaches in the presence of contact nonlinearities. It will be shown that in our contact case, a good accuracy can be obtained from a reduced models with very limited number of modes.
The Multiobjective Optimization of a Prismatic Drive
Authors: Bouyer E´milie , Caro Ste´phane , Chablat Damien , Angeles Jorge
Published: May 2009

The multiobjective optimization of Slide-o-Cam is reported in this paper. Slide-o-Cam is a cam mechanism with multiple rollers mounted on a common translating follower. This transmission provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. A Pareto frontier is obtained by means of multiobjective optimization. This optimization is based on three objective functions: (i) the pressure angle, which is a suitable performance index for the transmission because it determines the amount of force transmitted to the load vs. that transmitted to the machine frame; (ii) the Hertz pressure used to evaluate the stresses produced on the contact surface between cam and roller; and (iii) the size of the mechanism, characterized by the number of cams and their width.
Novel Design of a Robotic Gripper Allowing for In-Hand Manipulation
Authors: Voglewede Philip A.
Published: May 2009

The design of robotic end effectors can be loosely classified into two different types: complex anthropomorphic hands which allow for manipulation and simple open/close grippers which do not. This article investigates a design of a simple, industrial feasible end effector that allows for in-hand manipulation of parts. This end effector can be utilized in conjunction with a vision system to eliminate parts feeders and be able to pick parts straight from bins. The design utilizes passive joints that, when in a particular configuration, align (a self-motion singularity) to allow in-hand manipulation without regrasping or finger gaiting. A prototype end effector was fabricated and tested to prove the concept.
Experimental Study of Energy Pumping in Acoustics
Authors: Bellet Romain , Cochelin Bruno , Herzog Philippe , Mattei Pierre-Olivier
Published: May 2009

This paper presents an experimental vibro-acoustic set-up that aims to reproduce the energy pumping phenomenon between an acoustic medium and an essentially nonlinear oscillator. It shows a one-way irreversible transfer of energy between the first acoustic mode in a tube and a thin visco-elastic membrane. Various observed aspects of energy pumping are presented: behaviors under sinusoidal forcing, pumping threshold, resonance capture and transient response.
Motion-Based Shape Deformation of Solid Models
Authors: Wu Nier , Ilies¸ Horea T.
Published: May 2009

Mechanical designs undergo numerous geometric changes throughout the design process. Performing these changes relies, whenever possible, on the parametric models used to create the initial geometry. However, a number of open issues prevent the current parametric modeling systems to support many practical design situations, which, in turn, forces the geometry to evolve independently of the original parametric model. The fact that every parametric update can be expressed in terms of a sequence of shape deformations implies that the same geometric updates could be obtained, at least in principle, via shape deformation procedures that parameterize the deformation itself. In this paper we propose a new approach to create and edit solid models by introducing a geometric deformation procedure that relies on motion interpolation. We show that the proposed approach induces a parametrization of the deformation that allows direct control and editing of the deformation, is capable of preserving important geometric invariants such as constant cross-sectional properties of the deformed models, and maintains the ability to perform parametric optimization of the associated solid models. We conclude by discussing advantages and limitations of this approach as well as a number of important research directions that we will pursue in the near future.
Design and Development of a Novel Infant Surgical Table for 4-DOF Patient Manipulation
Authors: Ryland Kimberly , Nelson Carl A. , Hejkal Thomas
Published: May 2009

Retinopathy of Prematurity, caused by abnormal blood vessel development in the retina of premature infants, is a leading cause of childhood blindness. It is treated using laser photocoagulation. Current methods require the surgeon to assume awkward standing positions, which can result in injury to the surgeon if repeated often. To assist surgeons in providing quality care and prevent occupational injury, a new infant surgical table was designed. The engineered solution is an attachment to a standard surgical table, saving cost and space. This takes advantage of the adjustable height and tilt provided by the standard table, while 360° rotation designed into the attachment allows the surgeon to sit during surgery. The critical cords and tubes are routed through the attachment to avoid pulling and kinking. A four-bar locking mechanism allows easy attachment to standard medical railing. Finally, a straight line mechanism provides positive locking of the rotation, allowing precise positioning of the infant.
A 5-5 One-Degree-of-Freedom Fully Parallel Mechanism for the Modeling of Passive Motion at the Human Ankle Joint
Authors: Franci R. , Parenti-Castelli V.
Published: May 2009

This paper presents a new equivalent spatial mechanism for the passive motion simulation at the human ankle complex joint. The mechanism is based on the geometry of the main anatomical structures of the ankle complex, such as the shape of the talus and tibio/fibula bones at their interface, and the TiCal and CaFil ligament lengths. In particular, three sphere-to-sphere contact points at the interface have been identified and isometric fibers of both TiCal and CaFil ligaments have been considered to devise the equivalent mechanism. The proposed mechanism is a fully-parallel mechanism of type 5-5 with one degree of freedom. A procedure for the optimal synthesis of the mechanism is given. Simulation results compared with experimental data show the efficiency of the proposed mechanism to replicate the ankle passive motion, and also to reflect at the same time the main anatomical structures of the ankle joint. The new mechanism is believed to be a useful tool for both pre-operation planning and prosthesis design.
Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading
Authors: Jordy Daniel E. , Younis Mohammad I.
Published: May 2009

Squeeze film damping has a significant effect on the dynamic response of MEMS devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering the damping. By decreasing the size of the holes, the damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze-film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, we consider a G-sensor, which is a sort of a threshold accelerometer, employed in an arming and fusing chip. We study the effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate. We use a multi-physics finite-element model built using the software ANSYS. First, a modal analysis is conducted to calculate the out-of-plane natural frequency of the G-sensor. Then, a squeeze-film damping finite-element model, for both the air underneath the structure and the flow of the air through the perforations, is developed and utilized to estimate the damping coefficients for several hole sizes. Results are shown for various models of squeeze-film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. The extracted damping coefficients are then used in a transient structural-shock analysis. Finally, the transient shock analysis is used to determine the shock loads that induce contacts between the G-sensor and the underlying substrate. It is found that the threshold of shock to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.
Effect of a Circumferential Arc Crack on the Vibration Characteristics of a Flexible Spinning Disk
Authors: Nair Nikhit N. , Hashemi Hamid N. , Warner Grant M. , Olia M.
Published: May 2009

The vibration characteristics of a circumferentially cracked rotating disk are investigated. The disk is assumed to be axisymmetric, flexible and clamped at the center. The crack increases the local flexibility of the disk at the crack location and is modeled as linear and torsional springs, connecting the two segments of the disk. The spring constants are evaluated by considering crack opening displacements due to bending moment and shear force at the crack location. The equations of motion of two segments of the disk, for disk operating in vacuum as well as subjected to shear fluid flow are developed. Using the Finite Difference Technique, the coupled systems of equations are solved and the natural frequencies and mode shapes are obtained. The mode shapes are seen to be comparatively flattened in the inner region of the crack and heightened towards the periphery of the disk. Shear fluid loading reduces the natural frequencies and results in a quicker onset of instability. It is observed that the effect of the crack on the vibration characteristics of the disk is mainly a function of the crack location.
Using a Multibody Dynamic Simulation Code With Neural Network Technology to Predict Railroad Vehicle-Track Interaction Performance in Real Time
Authors: Martin Timothy P. , Zaazaa Khaled E. , Whitten Brian , Tajaddini Ali
Published: May 2009

Recently, there has been a large demand for predicting, in real time, the performance of multiple railroad vehicle types traversing existing track as the geometry of the track is being measured. To accurately predict a railroad vehicle’s response over a specified track requires the solution of nonlinear equations of motion and extensive calculations based on the suspension characteristics of the vehicle. To realize the real time goal, codes are being implemented that use linear approximations to the fully nonlinear equations of motion to reduce computation time at the expense of accuracy. Alternatively, neural network technology has the ability to learn relationships between a mechanical system input and output, and, once learned, give quick outputs for given input. The training process can be done using measured data or using simulation data. In general, measured data is very expensive to gather due to the instrumentation requirements and is most often not available. In this paper, the use of multibody simulation code as a training tool for a neural network is presented. The example results estimate the vertical and lateral forces at the wheel-to-rail interface as a function of the geometry of the track and the suspension characteristics of the vehicle type by using a multibody code with neural network technique.
Reliability Estimation for Time-Dependent Problems Using a Niching Genetic Algorithm
Authors: Li Jing , Mourelatos Zissimos P.
Published: May 2009

A reliability analysis method is presented for time-dependent systems under uncertainty. The system response is modeled as a parameterized random process. A double-loop optimization algorithm is used. The inner loop calculates the maximum response in time using a global-local search method, and transforms a time-dependent problem into a time-independent one. The outer loop calculates multiple most probable points (MPPs) which are commonly encountered in vibration problems. The dominant MPPs with the highest contribution to the probability of failure are identified. A niching genetic algorithm is used because of its ability to simultaneously identify multiple solutions. All potential MPPs are initially identified approximately and their location is efficiently refined using a gradient-based optimizer with local metamodels. Among all MPPs, the significant ones are identified using a correlation analysis. Approximate limit states are built at the identified MPPs, and the system failure probability is estimated using bi-modal bounds. The vibration response of a cantilever plate under random oscillating pressure load and a point load illustrates the proposed method. The finite-element model is used to calculate the response.
Validation of Distributed Risk Framework
Authors: Leung Peter , Ishii Kosuke , Benson Jan , Abell Jeffrey
Published: May 2009

Global companies realize the importance of collaborative design, or workshare, to develop products not only to target to a single market, but to sell them to the entire world. Workshare not only incorporates diverse customer values into the product development, but also introduces challenges in managing work distributions among global teams. As a result, the authors have developed a Distributed Risk Framework to quantify risk based on rework to facilitate workshare planning [5] [6]. The risk framework has been applied to several industry projects and it received positive feedback from the potential users of these pilot applications. To verify the risk results analytically, this paper seeks for statistical evidence to confirm the key assumption that motivates the development and the usage of the framework, with the assumption being that more distributed work results in a greater risk of rework. This paper begins with an overview of the risk framework followed by the steps of using actual rework data from the International Vehicle Company (IVC) to confirm the framework assumption. As a summary, this paper presents the contributions of the risk framework and the barriers to extend it to other distributed product development projects.
Grazing Bifurcations and Parametric Characterization of a Hysterically Damped Semi-Active Suspension System
Authors: Luo Albert C. J. , Rajendran Arun
Published: May 2009

The criterion for grazing motions in a hysterically damped semi-active suspension system is obtained from the local theory of non-smooth dynamical systems on the connectable and accessible domains. The generic mappings for such a suspension system are introduced. The sufficient and necessary conditions for grazing at the final states of mappings are expressed. The initial and final switching sets of grazing mapping, varying with system parameters, are illustrated for the grazing parametric characteristics. The initial and grazing, switching manifolds in the switching sets are defined through grazing mappings. Finally, numerical illustrations of grazing motions are very easily carried out with help of the analytical predictions. This paper provides a comprehensive investigation of grazing motions in the suspension system for a better understanding of the grazing mechanism of such a discontinuous system.
Evaluating Supplier Involvement Using DEA and Piecewise Triangular Fuzzy AHP
Authors: Yuan Shouhua , Tu Yiliu , Xue Deyi
Published: May 2009

Data Envelopment Analysis (DEA) has been widely applied in evaluating multi-criteria decision making problems which have multi-inputs and multi-outputs. However, the traditional DEA method does neither take the decision maker’s subjective preferences to the individual criteria into consideration, nor rank the selected options or decision making units (DMUs). On the other hand, Satty’s Analytical Hierarchy Process (AHP) was established to rank options or DMUs under multi-inputs and multi-outputs through pairwise comparisons. But in most cases, the AHP pairwise comparison method is not perfectly consistent, which may give rise to confusions in determining the appropriate priorities of each criterion to be considered. The inconsistency implicates the fuzziness in generating the relative important weight for each criterion. In this paper, a novel method which employs both DEA and AHP methods is proposed to evaluate the overall performance of suppliers’ involvement in the production of a manufacturing company. This method has been developed through modifying the DEA method into a weighting constrained DEA method by using a piecewise triangular weighting fuzzy set which is generated from the inconsistent AHP comparisons. A bias tolerance ratio (BTR) is introduced to represent the varying but restrained weighting values of each criterion. Accordingly, the BTR provides the decision maker a controllable parameter by tightening or loosening the range of the weighting values in evaluating the overall performance of available suppliers, which in hence, overcomes the two weaknesses of the traditional DEA method.