bluuebunny/crossref_metadata_2025 huggingface dataset:
EVALUATION OF THYROID TO BACKGROUND RATIOS AND COMPARISON OF VARIOUS SCINTIGRAPHIC MEASUREMENTS AND THEIR CORRELATION TO SERUM T4IN HYPERTHYROID CATS
Authors: Bettencourt Ann , Daniel Gregory B. , Panciera David , Larson Marti , Werre Stephen R.
Published: January 2016

Thyroid‐to‐salivary ratio and percent dose uptake are the most widely recognized scintigraphic measurements. Recently, the thyroid‐to‐background ratio has been proposed as an alternate method. However, this method has not been validated. The purpose of this observational, cross‐sectional, prospective study was to determine the location of a background region of interest (ROI) that is most reflective of blood pool activity. We also hypothesized that the thyroid‐to‐background ratio using this background ROI would be a better predictor of thyroid function. Fifty‐six cats presented to the Virginia‐Maryland College of Veterinary Medicine seeking radioiodine therapy for hyperthyroidism were enrolled in this cross‐sectional study to evaluating thyroid‐to‐background ratio. A blood sample for measuring plasma radioactivity was collected at the time of scintigraphy. The plasma radioactivity was compared to the background ROIs in eight anatomic regions. Scintigraphic measures of thyroid‐to‐background and thyroid‐to‐salivary ratios, and percent dose were then compared to serum T4. The heart ROI was most closely correlated with plasma pertechnetate activity (r= 0.70). Percent dose uptake was most closely correlated with serum T4(r= 0.74), followed by thyroid‐to‐salivary ratio (r= 0.66) and thyroid‐to‐background ratio using the heart ROI (r= 0.59). Thyroid‐to‐background ratio using the heart background ROI is a good predictor T4but percent dose uptake and thyroid‐to‐salivary ratio proved to be better predictors of T4than any of the thyroid‐to‐background ratios.
On the Regenerative Capabilities of Electrodynamic Dampers Using Bond Graphs and Model Predictive Control
Authors: Clemen Layne , Anubi Olugbenga Moses , Margolis Donald
Published: January 2016

There is a constant interest in the performance capabilities of active suspensions without the associated shortcomings of degraded fuel economy. To this effect, electrodynamic dampers are currently being researched as a means to approach the performance of a fully active suspension with minimal or no energy consumption. This paper investigates the regenerative capabilities of these dampers during fully active operation for a range of controller types—emphasizing road holding, ride, and energy regeneration. A model of an electrodynamic suspension is developed using bond graphs. Two model predictive controllers (MPCs) are constructed: standard and frequency-weighted MPCs. The resulting controlled system is subjected to International Organization for Standardization (ISO) roads A–D and the results are presented. For all of the standard MPC weightings, the suspension was able to recover more energy than is required to run the suspension actively. All of the results for optimal energy regeneration occurred on the standard Pareto tradeoff curve for ride comfort and road holding. Frequency weighting the controller increased suspension performance while also regenerating 3–12% more energy than the standard MPC.
Design of a Linear Bistable Compliant Crank–Slider Mechanism
Authors: Alqasimi Ahmad , Lusk Craig , Chimento Jairo
Published: January 2016

This paper presents a new model for a linear bistable compliant mechanism and design guidelines for its use. The mechanism is based on the crank–slider mechanism. This model takes into account the first mode of buckling and postbuckling behavior of a compliant segment to describe the mechanism's bistable behavior. The kinetic and kinematic equations, derived from the pseudo-rigid-body model (PRBM), were solved numerically and are represented in plots. This representation allows the generation of step-by-step design guidelines. The design parameters consist of maximum desired deflection, material selection, safety factor, compliant segments' widths, maximum force required for actuator selection, and maximum footprint (i.e., the maximum rectangular area that the mechanism can fit inside of and move freely without interfering with other components). Because different applications may have different input requirements, this paper describes two different design approaches with different parameters subsets as inputs. The linear bistable compliant crank–slider mechanism (LBCCSM) can be used in the shape-morphing space-frame (SMSF) as potential application. The frame's initial shape is constructed from a single-layer grid of flexures, rigid links, and LBCCSMs. The grid is bent into the space-frame's initial cylindrical shape, which can morph because of the inclusion of LBCCSMs in its structure.
Simulation Analysis of Casing Vibration Response and Its Verification Under Blade–Casing Rubbing Fault
Authors: Wang H. F. , Chen G. , Song P. P.
Published: January 2016

A new rotor–stator rubbing model considering the blade–casing rubbing fault is put forward in this paper. The model couples the rotor together with its suspension (ball or roller bearings), the disk, the (multiple) blades, and the casing. In addition, the influence of the rotor–stator clearance on rubbing forces was considered. It can simulate rubbing faults for single-point rubbing on the casing and complete-cycle rubbing on the rotor. The new rubbing model was applied to the rotor–support–casing coupling model, and the casing acceleration response under rubbing faults was obtained by the time-integration approach. The casing acceleration response, blade tip response, and rubbing force were analyzed. An aero-engine rotor tester, including casing, was used to carry out the rubbing experiment for single-point rubbing on the casing and for whole-cycle rubbing on the rotor. The simulation results were found in highly consistent with the experimental results, which fully verified the effectiveness of the new blade–casing rubbing model.
Ray Tracing Using Radial Basis Function Networks
Authors: Wiens Travis
Published: January 2016

This paper presents a numerical method of tracing of sound or other refracted rays through a medium with arbitrarily varying refractive index. The method uses a radial basis function (RBF) network to define the refractive index of the medium, allowing continuous gradients to be determined analytically and the ray path to be solved using standard numerical ordinary differential equation (ODE) solution techniques.
Innovative AF VCM Actuator for Smart Phone Camera Module
Authors: Liu Chien-Sheng , Li Hong-Fei , Lee Min-Kai
Published: January 2016

In the present study, we propose an innovative autofocusing (AF) voice coil motor (VCM) actuator to replace the traditional AF VCM actuators with springs for smart phone camera modules. In the proposed electromagnetic structure, the magnetic pre-compression force between the two guide rods and permanent magnet is used to replace the restoring resilience force of the two springs in the traditional AF VCM actuators. The proposed AF VCM actuator is characterized numerically using the simulation analysis of commercial software Infolytica MagNet and then verified experimentally using a laboratory-built prototype. The experimental results presented in this study show compared to traditional AF VCM actuator, the proposed AF VCM actuator has excellent AF performance to be able to replace the traditional AF VCM actuators. As a result, the proposed device provides a promising solution for smart phone camera modules or industrial applications.
A Computational Study on the Mechanical Power Loss of a Spur Gear Pair Under the Thermal Tribo-Dynamic Condition
Authors: Li Sheng
Published: January 2016

This study proposes a formulation for the description of the gear mesh mechanical power loss under the thermal tribodynamic condition. A six degree-of-freedom motion equation set that models the vibratory motions of a general spur gear pair is coupled with the governing equations for the description of the gear thermal mixed elastohydrodynamic lubrication to include the interactions between the gear dynamics and gear tribology disciplines in the modeling of the gear mesh mechanical power loss. The important role of the gear thermal tribo-dynamics in power loss is demonstrated by comparing the predictions of the proposed model to those under the thermal quasi-static condition, and the iso-thermal tribo-dynamic condition, respectively.
Nonlinear Vibrations and Instability of Shallow Pyramidal Trusses
Authors: de Castro Carlos Henrique L. , Gonçalves Paulo B. , Orlando Diego
Published: January 2016

Pyramidal space trusses are a basic component of several structures, from carbon nanostructures to large geodesic domes. These structures, such as the classical Von Mises truss, have a highly non-linear response in the presence of static and dynamic loads. The geometric nonlinearity is particularly significant, even at low load levels when these structures are shallow, that is, has a small height to base ratio. This paper presents an exact non-linear formulation for a shallow pyramidal truss composed of n equally spaced bars. Based on this formulation, the loss of stability and nonlinear vibrations of these structures under static and dynamic loads is analyzed. To understand its nonlinear behavior, time responses, phase portraits, bifurcation diagrams, energy profiles and basins of attraction are obtained. The results highlight the complex nonlinear dynamics of this class of structures and its major influence in design.
Evaluation of Haptic Modules for Training in Undergraduate Mechanics
Authors: Karadogan Ernur , Williams Robert L. , Karadogan Figen
Published: January 2016

This article reports the evaluation results of the software modules we are developing to augment teaching and learning in standard required undergraduate engineering mechanics courses. Using these modules, students can change parameters, predict answers, compare outcomes, interact with animations, and “feel” the results using a force feedback joystick. The overall system aims to increase teaching and learning effectiveness by rendering the concepts compelling, fun, and engaging. Three software modules in Dynamics were evaluated by a sample of the target population, 40 undergraduate engineering students who were enrolled in a sophomore-level Dynamics course during the evaluation. Students showed significant preference in that the modules would increase their interest in Dynamics subject and their engagement in the Dynamics course that they were enrolled at the time of the evaluation. Evaluation results also showed significant difference in preference in that the modules would improve students’ both conceptual understanding of the Dynamics subjects and problem-solving skills. Tactile learners believed that the modules would improve their conceptual understanding of Dynamics subjects more than the visual learners. 97.5% of the students were willing to use the software again in the future. 92.5% of the students believed that the incorporation of this software to the instruction of Dynamics would be beneficial to their learning.
Optimization of Profile Modifications With Regard to Dynamic Tooth Loads in Planetary Gears With Flexible Ring-Gears
Authors: Chapron Matthieu , Velex Philippe , Bruyère Jérôme , Becquerelle Samuel
Published: January 2016

This paper deals with the optimization of tooth profile modifications in planetary gears. A dynamic model is proposed based on 3D two-node gear elements connected to a deformable ring-gear discretized into beam elements. Symmetric tip relief on external and internal gear meshes are introduced as normal deviations along the lines of contact superimposed on a stiffness distribution aimed at simulating position- and time-varying mesh stiffness functions. The equations of motion are solved by the combination of a Newmark’s time-step integration scheme and a contact algorithm to account for possible partial or total contact losses. Symmetric linear profile modifications are then optimized by using a genetic algorithm with the objective of minimizing dynamic tooth loads over a speed range. Finally, the interest of the corresponding optimum profile modifications with regard to speed and torque variations is analyzed.
Beyond Optimal Sequencing: Defining Part Orientation and Worker Allocation in Assembly
Authors: Rafibakhsh Nima , Campbell Matthew I.
Published: January 2016

Assembly Sequence planning is a tedious but crucial task in manufacturing a product. A good assembly plan will lead to minimum wasted time and maximum capacity of resources. Typically, research in Automated Assembly Planning and Assembly Sequence Planning (AAP and ASP) only define the sequence that the parts should be assembled with no information for specifying additional details to make the plan complete and optimal. In this paper we introduce a post-processing step (after the sequence of parts has been found) with focus on optimal part orientation and worker allocation. The paper has two main sections: the first section uses Dijkstra’s algorithm to obtain part orientation with minimum assembly cost. For the second part of the paper, a novel approach is proposed based on a line balancing technique to find the minimum number of workers needed to achieve the minimum make-span time. These necessary details in AAP give real time feedback to designers to analyze their design with production and assembly line information.
Automated Synthesis of Planar Mechanisms With Revolute, Prismatic and Pin-in-Slot Joints
Authors: Huang Weifeng , Campbell Matthew I.
Published: January 2016

This paper presents a graph synthesis approach to planar N-bar mechanisms with revolute (R), prismatic (P), and RP (pin-in-slot) joints. This novel graph synthesis method extends the enumeration to define the possible topologies for mechanisms with any mix of R-, P-, and RP-joints. Each topology is explicitly defined as a graph which can be viewed and simulated within an online kinematic simulator. This method successfully produces the same number of topologies for 6, 8, 10, and 12-bar revolute joint mechanisms as those shown in the existing literature. It explicitly calculates all topologies for 6, 8, and 10 bars with a mix of the three joint-types.
Non-Negative Matrix Factorization Based Uncertainty Quantification Method for Complex Networked Systems
Authors: Mukherjee Arpan , Rai Rahul , Singla Puneet , Singh Tarunraj , Patra Abani
Published: January 2016

The behavior of large networked systems with underlying complex nonlinear dynamic are hard to predict. With increasing number of states, the problem becomes even harder. Quantifying uncertainty in such systems by conventional methods requires high computational time and the accuracy obtained in estimating the state variables can also be low. This paper presents a novel computational Uncertainty Quantifying (UQ) method for complex networked systems. Our approach is to represent the complex systems as networks (graphs) whose nodes represent the dynamical units, and whose links stand for the interactions between them. First, we apply Non-negative Matrix Factorization (NMF) based decomposition method to partition the domain of the dynamical system into clusters, such that the inter-cluster interaction is minimized and the intra-cluster interaction is maximized. The decomposition method takes into account the dynamics of individual nodes to perform system decomposition. Initial validation results on two well-known dynamical systems have been performed. The validation results show that uncertainty propagation error quantified by RMS errors obtained through our algorithms are competitive or often better, compared to existing methods.
Extended Nonlinear Analysis of Exactly-Constrained Compliant Compound Parallelogram Mechanisms
Authors: Hao Guangbo , Li Haiyang , Joseph George
Published: January 2016

Extended nonlinear analysis of compliant compound parallelogram mechanisms is conducted in this paper. The analytical nonlinear model of a compound basic parallelogram mechanism (CBPM) is first derived incorporating the initial internal axial force. The stiffness equations of compound multi-beam parallelogram mechanisms (CMPMs) are then followed. The effect of initial internal axial forces on the primary motion is further analyzed, which can be employed to consider active displacement preloading control and thermal effects etc. It is shown that negative initial internal axial force will reduce the primary stiffness, and vice versa. The criteria for which the primary stiffness may be considered “constant” is defined and the initial internal axial force driven by temperature change is also formulated. The dynamic analysis of a CMPM using nonlinear finite element analysis (FEA) is finally carried out to show the modal frequency and the forced excitation response in the primary motion direction.
Modeling and Hardware-in-the-Loop Simulation of Power-Split Device for Hybrid Electric Vehicles
Authors: Joshi Shreyash , Chen Bo
Published: January 2016

Conventional vehicles are creating pollution problems, global warming and the extinction of high density fuels. To address these problems, automotive companies and universities are researching on hybrid electric vehicles where two different power devices are used to propel a vehicle. This research studies the development and testing of a dynamic model for Prius 2010 Hybrid Synergy Drive (HSD), a power-split device. The device was modeled and integrated with a hybrid vehicle model. To add an electric only mode for vehicle propulsion, the hybrid synergy drive was modified by adding a clutch to carrier 1. The performance of the integrated vehicle model was tested with UDDS drive cycle using rule-based control strategy. The dSPACE Hardware-In-the-Loop (HIL) simulator was used for HIL simulation test. The HIL simulation result shows that the integration of developed HSD dynamic model with a hybrid vehicle model was successful.
The Realization of Engineered Systems With Considerations of Complexity
Authors: Smith Warren F. , Milisavljevic Jelena , Sabeghi Maryam , Allen Janet K. , Mistree Farrokh
Published: January 2016

This paper is the product of thoughts for exploring the model-based realization of engineered systems. The question addressed is that given a relevant model, what new knowledge, understanding of emergent properties and insights can be gained by exercising the model? From the perspective that the activity of designing is a decision making process, it follows that better decisions will be made when a decision maker is better informed about the available choices and the ramification of these choices. In the context of an example of designing a small thermal plant, a description of an approach to exploring the solution space in the process of designing complex systems and uncovering emergent properties is presented.
Is Our Universe Accelerating Dynamics Fractional Order?
Authors: Zeng Caibin , Chen YangQuan , Podlubny Igor
Published: January 2016

In this paper, a fractional dynamics approach is used to characterize the observed accelerating expansion of the universe. We claim that the evolution of accelerating expansion obeys an α-exponential function, which is the fundamental solution of linear fractional order dynamical equation. We find that the Hubble constant is 67.8807, 68.2546, and 67.9119 for all redshift z < 1.5, z < 1, and z < 0.1 based on the dataset collected by the Supernova Cosmology Project. Furthermore, we verify that the expansion rate of our universe is speeding up and actually obeys a Mittag-Leffler law.
Study of Targeted Energy Transfer Inside 3D Acoustic Cavity by Two Nonlinear Membrane Absorbers
Authors: Shao Jianwang , Wu Xian , Cochelin Bruno
Published: January 2016

The targeted energy transfer (TET) phenomenon has been observed in the field of acoustics, which provides a new approach to passive sound control in low frequency domain. The TET phenomenon has been investigated firstly inside one tube (1D acoustic system) with a membrane nonlinear energy sink (NES) or a loudspeaker nonlinear absorber, then inside an acoustic cavity (3D acoustic system) with a membrane NES. 3D acoustic cavities have been considered as more general geometry for the acoustic medium in view of applications in the acoustic field and the membrane NES is mounted directly on the wall of the acoustic cavity. The placement of a membrane NES on the wall involves a weak coupling between the membrane NES and a considered acoustic mode, which constitute the two degrees-of-freedom (DOF) system. The beginning of TET phenomenon of the two DOFs system has been analyzed and the desired working zone for the membrane NES has also been defined. The two thresholds of the zone have been determined by an analytical formula and semi-analytically, respectively. The parametric analysis of the membrane NES by using the two DOFs system has been investigated to design the membrane NES. In order to enhance the robustness and the effective TET range in acoustic cavities, a three DOFs system with two membranes and one acoustic mode is studied in this paper. We consider two different membranes and two almost identical membranes to analyze the TET phenomenon, respectively. The desired working zone for the membrane NES and the value of the plateau which are obtained by the two DOFs system are applied to analyze the three DOFs system. We observe that two membranes can enlarge the desired working zone of the NES.
An Algebraic Method to Check the Singularity-Free Paths for Parallel Robots
Authors: Jha R. , Chablat D. , Rouillier F. , Moroz G.
Published: January 2016

Trajectory planning is a critical step while programming the parallel manipulators in a robotic cell. The main problem arises when there exists a singular configuration between the two poses of the end-effectors while discretizing the path with a classical approach. This paper presents an algebraic method to check the feasibility of any given trajectories in the workspace. The solutions of the polynomial equations associated with the trajectories are projected in the joint space using Gröbner based elimination methods and the remaining equations are expressed in a parametric form where the articular variables are functions of time t unlike any numerical or discretization method. These formal computations allow to write the Jacobian of the manipulator as a function of time and to check if its determinant can vanish between two poses. Another benefit of this approach is to use a largest workspace with a more complex shape than a cube, cylinder or sphere. For the Orthoglide, a three degrees of freedom parallel robot, three different trajectories are used to illustrate this method.
A Laser Calibration Device for Mini Robots
Authors: Legnani Giovanni , Gabrielli Andrea , Ousdad Abdelmajid , Fassi Irene , Ruggeri Serena , Fontana Gianmauro
Published: January 2016

The paper describes a new laser device conceived for surface scanning and more specifically for mini robot calibrations. The system is based on a laser triangulation sensor which is moved by an extremely accurate device to collect a set of 3D points lying on surfaces. If the surfaces belong to the gripper of a robot that must be calibrated and a sufficient number of points of this gripper are collected, the pose of the robot can be measured. If the robot is moved to several different configurations and the gripper poses are measured for each of them, it is possible to reconstruct the kinematics of the robot and calibrate it. The paper presents the theory and describes the design, tests and calibration of the laser instrumentation with a focus on the first experimental results. These results are obtained in a working cell including a vision system, a 4-dof (xyz,θ) mini robot and a 2-dof rotating platform.
Development of On-Line Condition Monitoring System for Wind Turbines in Plant Level
Authors: Liu Chun-yang , Li Ji-shun , Xue Yu-jun , Ma Wei , Sui Xin , Yang Fang , Ma Xi-qiang
Published: January 2016

The maintenance cost of wind turbines has become the significant challenge for the wind power enterprise. One available way to reduce the cost is to monitor the wind turbines and make preventative maintenance. In this paper, an on-line condition monitoring system for wind turbines in plant level was presented. A 4-level monitoring structure was designed for the system, and the network communication was used to transmit the data efficiently. A high performance digital signal processor (DSP) was used as the processing core in the signal acquisition device. A computer software was also developed for data analysis and remote management of the monitoring device. The vibrations, temperature, and some other information of the turbines were gathered synchronously. The monitoring center in wind farm, the data center of wind power enterprise and the remote service center of equipment supplier can know the operation condition of wind turbines well. It would be useful for wind power enterprise to obtain the operation condition of wind turbine and reduce the cost of maintenance.
An Optimization Model for Manufacturing Systems in an Uncertain Environment
Authors: Mitnovitsky Michael , Weiss Cohen Miri , Shpitalni Moshe
Published: January 2016

This paper examines a flexible job shop problem that considers dynamic events, such as stochastic job arrivals, uncertain processing times, unexpected machine breakdowns and the possibility of processing flexibility. To achieve this goal, a new agent-based adaptive control system has been developed at the factory level, along with advanced decision-making strategies that provide responsive factories with adaptation and reconfiguration capabilities and advanced complementary scheduling abilities. The aim is to facilitate operational flexibility and increase productivity as well as offer strategic advantages such as analysis of factory development options by simulation. The feasibility of the proposed system is demonstrated by simulation under various experimental settings, among them shop utilization level, due date tightness and breakdown level.
Comparison of Multibody Dynamics Solver Performance: Synthetic Versus Realistic Data
Authors: Lu Ying , Trinkle Jeff
Published: January 2016

In the area of robotics simulation, multibody dynamics plays an important role in designing and controlling robots, especially when the robot contacts the environment. Contacts give rise to non-penetration and friction constraints, which are nonsmooth and nonlinear. One way to simulate such systems is through the use of a discrete-time multibody dynamics model in the form of a nonlinear complementarity problem (NCP), for which, finding a solution is known to be NP-hard [1]. In situations where analytical solutions don’t exist, a suite of numerical solutions accessible through a benchmarking framework is useful to fairly evaluate performance of different computer algorithms. However, many algorithm designers don’t have easy access to test data from physical simulators. Under such circumstances, randomized data are used to test the performance of solution algorithms.

In this paper, we present our Benchmark Problems of Multibody Dynamics (BPMD) framework and database, with the data sets from different physics engines, as a benchmarking platform. Then we compare the performance of several solvers on synthetic data and simulation data, to show the superiority of testing solution algorithms with simulation data over testing with synthetic data. We will show that algorithm tested only on synthetic data often fail to solve problem obtained from physics simulations, to demonstrate the benefit of BPMD database.
A Novel Micro Heater Integrated on Flexible Polyimide Substrate With Fast Response and Uniform Temperature Distribution
Authors: Yu Shifeng , Wang Shuyu , Lu Ming , Zuo Lei
Published: January 2016

This paper presents a novel micro heater prepared on polyimide thin film with fast response and ultra-uniform temperature distribution in the heating area. The transparent polyimide thin film was fabricated by spin-coating, baking and curing the liquid polyimide on the silicon wafer. A gold heater together with the vanadium oxide based thermistor was integrated on the polyimide thin film. Due to the low thermal conductivity of the polyimide thin film, the MEMS heater could reach high temperature with low power consumption and fast response time. FEA method was applied to optimize the shape of the gold heater to achieve uniform temperature distribution along the heating area. A copper island was also deposited on the back of the heater to improve the uniformity of the temperature distribution. The vanadium oxide based temperature sensor with a high temperature coefficient of resistivity as 2.4% was used for the temperature sensing. The temperature variation among the heating area is less than 0.2°C.
Kinematic Analysis and Trajectory Planning of the Orthoglide 5-Axis
Authors: Caro S. , Chablat D. , Lemoine P. , Wenger P.
Published: January 2016

The subject of this paper is about the kinematic analysis and the trajectory planning of the Orthoglide 5-axis. The Orthoglide 5-axis a five degrees of freedom parallel kinematic machine developed at IRCCyN and is made up of a hybrid architecture, namely, a three degrees of freedom translational parallel manipulator mounted in series with a two degrees of freedom parallel spherical wrist. The simpler the kinematic modeling of the Orthoglide 5-axis, the higher the maximum frequency of its control loop. Indeed, the control loop of a parallel kinematic machine should be computed with a high frequency, i.e., higher than 1.5 MHz, in order the manipulator to be able to reach high speed motions with a good accuracy. Accordingly, the direct and inverse kinematic models of the Orthoglide 5-axis, its inverse kinematic Jacobian matrix and the first derivative of the latter with respect to time are expressed in this paper. It appears that the kinematic model of the manipulator under study can be written in a quadratic form due to the hybrid architecture of the Orthoglide 5-axis. As illustrative examples, the profiles of the actuated joint angles (lengths), velocities and accelerations that are used in the control loop of the robot are traced for two test trajectories.
A New Sequential Multi-Disciplinary Optimization Method for Bi-Level Decomposed Systems
Authors: Zhou Jianhua , Li Mian , Xu Min
Published: January 2016

Multi-discipline optimization (MDO) has been proposed to handle complex optimization problems with multiple disciplines or subsystems. These problems are with global and coupling variables that are shared by more than one subsystem, which is one of the major challenges for these problems. Diverse methods that can be classified as of single- and multi-levels have been developed aiming to solve those problems. Most of these methods do not give optimization autonomies to each subsystem concerning these shared variables. This study proposed that for decomposed bi-level MDO problems, each subsystem is given full optimization autonomy in the initial stage to decide possible best solutions individually. Then all the obtained solutions are given to the system that will process the information and dispatch shared variables to each subsystem. Based on these dispatched variables, subsystems will sequentially perform the corresponding optimization with respect to their local (and global) variables with additional consistency constraints. There is no nested optimization between the system and subsystems. Six numerical and engineering examples are tested and comparisons with other methods are made to demonstrate the efficiency and applicability of the proposed approach.
Toward MEMS Displacement Sensor Based on Resonant Frequency Monitoring of Slightly Curved Beams
Authors: Krakover Naftaly , Ilic Bojan R. , Krylov Slava
Published: January 2016

In this work we report on operational principle, design and characterization of a generic electrostatically actuated micro displacement/acceleration sensor based on frequency monitoring of an initially curved double-clamped microbeam actuated by a close gap electrode. The displacement of the electrode attached to a proof mass results in varying electrostatic force and changing effective stiffness and frequency of the beam. The sensitivity is improved by choosing the working configurations in the vicinity of the critical snap-through buckling points of the beam. Reduced order model of the device was built by means of Gelerkin decomposition and was used for the feasibility study, evaluation of the design parameters and comparison with the experimental data. Devices of several configurations, which included initially straight as well as curved beams were fabricated from single crystal silicon and operated in open air environment. The responses were registered optically by laser Doppler vibrometry (LDV). Consistently with the model prediction, significant reduction in the frequency in the vicinity of the critical point followed by an increase of the frequency in the post-buckling configurations was observed in the experiments. Our theoretical and experimental results collectively demonstrate the feasibility of the suggested approach.
Use of ANCF Finite Elements in MBS Textile Applications
Authors: Wang Liang , Wang Yongxing , Recuero Antonio M. , Shabana Ahmed A.
Published: January 2016

The objective of this investigation is to present a new flexible multibody system (MBS) approach for modeling textile roll-drafting sets used in chemical textile industry. The proposed approach can be used in the analysis of textile materials which have un-common material properties best described by specialized continuum mechanics constitutive models, for instance, the lubricated polyester filament bundles (PFB) presented in this paper. In this investigation, PFB is modeled as a hyper-elastic transversely isotropic material using absolute nodal coordinate formulation (ANCF). The PFB strain energy density function is decomposed into a fully isotropic component and an orthotropic, transversely isotropic component expressed in terms of five invariants of the right Cauchy-Green deformation tensor. Using this energy decomposition, the second Piola-Kirchhoff stress and the elasticity tensors can also be split into isotropic and transversely isotropic parts. Constitutive equations are used to evaluate the generalized material forces associated with the coordinates of three-dimensional fully-parameterized ANCF finite elements. The proposed model allows for modeling the dynamic interaction between the rollers and PFB and allows for using spline functions to specify the PFB forward velocity. The paper demonstrates that the textile material constitutive equations and the MBS algorithms can be used effectively to obtain numerical solutions that define the state of strain of the textile material and the relative slip between rollers and PFB and therefore provide a good method to study the roll-drafting process in the chemical textile industry.
Chaotic Chemical Reaction Optimization Approach to Receding Horizon Control for Multiple UAVs Formation
Authors: Zhang Zenghu , Duan Haibin
Published: January 2016

In this paper, a chaotic chemical reaction optimization approach to receding horizon control is proposed for multiple unmanned aerial vehicles formation. To keep the coordinated formation with the minimum cost value in all of the planning horizons, the unmanned aerial vehicles formation problem is converted to online optimization problems by giving a receding horizon control scheme. The chemical reaction optimization algorithm is a new optimization inspired by the nature of chemical reactions. Furthermore, the chaotic operator is utilized to help the optimization algorithm avoid of the local optimum and find better optimal parameters. Comparative results show that our proposed method outperforms over traditional particle swarm optimization algorithm.
Development and Testing of a Low Cost Wearable and Portable Hand Exoskeleton Based on a Parallel Mechanism
Authors: Allotta B. , Conti R. , Governi L. , Meli E. , Ridolfi A.
Published: January 2016

In this research work, the authors developed and tested a low cost wearable and portable hand exoskeleton to assist people with physical disabilities in their everyday lives. Focusing on hand opening disabilities, the proposed actuated orthoses could support and enable daily gestures such as shacking hands or grasping objects. The Hand Exoskeleton System (HES) prototype is based on a cable-driven architecture applied to a single-phalanx mechanism. The preliminary prototype of the system has been successfully built and is currently under testing with a patient to verify its performance from a patient viewpoint.
A Model for the Estimation of Pressure Ripple in Tandem Gear Pumps
Authors: Battarra Mattia , Mucchi Emiliano , Dalpiaz Giorgio
Published: January 2016

The present paper addresses the development of a lumped parameters model used to analyze the dynamic behavior of a so-called tandem gear pump. The pump is composed of two coaxial stages, both with external gears: a high pressure stage with spur gears and a low pressure one with helical gears. In particular, the paper deals with the modelling and the analysis of the phenomena bound to the pressure distribution around the gears, since they have the most important effect in the dynamic behavior of the pump. The pressure variation in the inlet and outlet chambers, the variable pressure in the trapped volume as well as the pressure evolution from the low to the high pressure chamber is estimated based on the Euler’s approach. The model is developed in Matlab environment. Attention is particularly focused on the description of the methodology adopted for modelling the low-pressure stage, constituted by helical gears, and its influence on the calculation of the pump geometrical parameters. The results provided by the numerical model are compared with experimental measurements in terms of outlet pressure ripple and volumetric efficiency under different working conditions. The results of the validation can be considered satisfactory. Predicted pressure ripple is shown and the effects of interconnections between stages are analyzed studying the outlet pressure ripple in the frequency domain as well.
Development of a Control Theoretic Alternative to Fitts’ Law With Application to In-Vehicle Touchscreen Interface
Authors: Wang Chao , Ravani Bahram
Published: January 2016

A control theoretic alternative to Fitts’ Law based on a modified crossover model is proposed. A physical interpretation of the model offers the unification of various different formulations of Fitts’ Law. Model identification and validation is carried out for a target acquisition task using a touchscreen. A brief treatment of noise generated by random relative movement between the human operator and the touchscreen (such as in-vehicle touchscreen based devices) is considered using the proposed model.
A Medical Device for Patellofemoral Disorders: Design and Development
Authors: Leal Ana , Pereira Rogério , Pereira Hélder , Flores Fernandes João Paulo , Silva Filipe , Espregueira-Mendes João
Published: January 2016

Patellofemoral disorders have been recognized as one of the major causes of the human knee articulation problems. In general, the current available methods to assess patellofemoral joint disorders include the analysis of clinical history, clinical tests and imaging exams. These approaches are ambiguous in the diagnosis produced since they strongly depend on the expertise of the examinant. With the purpose to assist in the diagnosis process of the patellofemoral disorders, a new medical device is proposed throughout this work. In the sequel of this process, the identification and full characterization of the main issues associated with patellofemoral joint are presented. The main features and the engineered solution are accuracy and reproducibility, possibility of incorporation into imaging equipment, adaptability to a large range of knee sizes, easy and cheap to manufacture and anatomically and ergonomically fashion. The mechanical system designed and built allows for the measurement and quantification of the most significant patellofemoral joint motions, more precisely the medial-lateral translation, internal-external tilt and internal-external rotation. The validation of the medical device is investigated here by analyzing the data produced from actual clinical exams, being the early results quite satisfactory and very promising for extensive use in helping in the diagnosis of the patellofemoral disorders.
Tool-Tissue Force Estimation for a 3-DOF Robotic Surgical Tool
Authors: Zhao Baoliang , Nelson Carl A.
Published: January 2016

Robotic minimally invasive surgery has achieved success in various procedures; however, the lack of haptic feedback is considered by some to be a limiting factor. The typical method to acquire tool-tissue reaction forces is attaching force sensors on surgical tools, but this complicates sterilization and makes the tool bulky. This paper explores the feasibility of using motor current to estimate tool-tissue forces, and demonstrates acceptable results in terms of time delay and accuracy. This sensorless force estimation method sheds new light on the possibility of equipping existing robotic surgical systems with haptic interfaces that require no sensors and are compatible with existing sterilization methods.
Predicting the Benefits of Topology Optimization
Authors: Deng Shiguang , Suresh Krishnan
Published: January 2016

Topology optimization is a systematic method of generating designs that maximize specific objectives. While it offers significant benefits over traditional shape optimization, topology optimization can be computationally demanding and laborious. Even a simple 3D compliance optimization can take several hours. Further, the optimized topology must typically be manually interpreted and translated into a CAD-friendly and manufacturing friendly design.

This poses a predicament: given an initial design, should one optimize its topology? In this paper, we propose a simple metric for predicting the benefits of topology optimization. The metric is derived by exploiting the concept of topological sensitivity, and is computed via a finite element swapping method. The efficacy of the metric is illustrated through numerical examples.
The Effects of Soldier Gear Encumbrance on Restraints in a Frontal Crash Environment
Authors: Karwaczynski Sebastian K. , Hoover Ryan W. , Jessup Chris P. , Paulson Kyle M.
Published: January 2016

Crash testing and validation of Military vehicles has not to date, accounted for the Soldier gear burden. Actual loads imparted onto the occupant in a representative Military vehicle crash test environment have been limited and do not reflect what an occupant would actually see in this type of an event. The US Army Soldier encumbered with his gear poses a challenge in restraint system design that is not typical in the automotive world. The weight of the gear encumbrance may have a significant effect on how the restraint system performs and protects the occupant during a frontal event. Other system level complications to Military vehicle interiors are secondary impact surfaces, such as instrument panels, ammunition cans and weaponry which provide a path for off-loading the energy generated by the occupant and gear combination. The energy absorption of these surfaces however, is not ideal in current Military vehicle designs and may result in injury or death.

The goal of this study was to investigate gear and accelerative pulses as they relate to the restraints and occupant interaction. Data from this study will be used for further restraint development. To limit experimental variation a fixed steel seat structure was utilized throughout the entire testing series. It is hypothesized that determining these effects will lead to a restraint system design that can be optimized to provide restraint for the whole range of occupant sizes and gear variations. Further reductions in occupant injury are achieved by properly tuning the surrounding trim, air bags and cargo contact surfaces.

Results of this study indicate the inclusion of the soldier gear may increase the likelihood of occupant excursion and injury. Variation in accelerative pulses resulted in lower injury values and occupant displacements.
Trajectory Generation for Three-Degree-of-Freedom Cable-Suspended Parallel Robots Based on Analytical Integration of the Dynamic Equations
Authors: Jiang Xiaoling , Gosselin Clément
Published: January 2016

This paper proposes a trajectory generation technique for three-dof planar cable-suspended parallel robots. Based on the kinematic and dynamic modelling of the robot, positive constant ratios between cable tensions and cable lengths are assumed. This assumption allows the transformation of the dynamic equations into linear differential equations with constant coefficients for the positioning part, while the orientation equation becomes a pendulum-like differential equation for which accurate solutions can be found in the literature. The integration of the differential equations is shown to yield families of translational trajectories and associated special frequencies. This result generalizes the special cases previously identified in the literature. Combining the results obtained with translational trajectories and rotational trajectories, more general combined motions are analysed. Examples are given in order to demonstrate the results. Because of the initial assumption on which the proposed method is based, the ratio between cable forces and cable lengths is constant and hence always positive, which ensures that all cables remain under tension. Therefore, the acceleration vector remains in the column space of the Jacobian matrix, which means that the mechanism can smoothly pass through kinematic singularities. The proposed trajectory planning approach can be used to plan dynamic trajectories that extend beyond the static workspace of the mechanism.
Automatically Synthesizing Principle Solutions in Multi-Disciplinary Conceptual Design With Functional and Structural Knowledge
Authors: Qi Jin , Hu Jie , Zhu Guoniu , Peng Yinghong
Published: January 2016

Synthesizing principle solutions (PSs) in various disciplines together is a common practice in multi-disciplinary conceptual design (MDCD), which generates the combination of PSs to meet the desired functional requirement. Different from structure- and function-based synthesis methods, a hybrid PS synthesis (HPSS) method through integrating functional and structural knowledge is proposed in this paper, which not only achieves the automated synthesis of multi-disciplinary PSs, but also resolves the undesired physical conflicts during the synthesis process. It comprises of united representation approach for modeling functional and structural knowledge of multi-disciplinary PSs, adapted agent-based approach for chaining the specified functional flows of PSs, and the extension conflict resolve approach for handling the partial design conflicts among selected PSs. An industrial case study on the emergency cutting off (ECO) device design was given to validate the applicability of HPSS, and it indicates that HPSS can not only get multi-disciplinary design result of ECO device, but also further resolve the design conflict (i.e., vibration impact) to optimize the functional structure of ECO device.