bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Transmission Accuracy Analysis of an RV Reducer Rigid-Flexible Coupled Effect
Authors: Cao Dai-jia , Zhu Cai-chao , Guo Pei-lin , Du Xue-song , Liu Huai-ju
Published: November 2017

RV reducers are widely used in high-precision gear transmissions. Assembly errors and elastic deformation of the components have great influence on the transmission accuracy, which is an important indication on the evaluation of performance. A RV reducer dynamic transmission accuracy analysis model is established which is based on the rigid-flexible coupled multibody dynamics. For the modelling, the input gear shaft, the planetary gear, the crankshaft, the cycloid gear and the pin gear are considered as flexible bodies, while other components are identified as rigid bodies. Based upon the model, the influence of geometric errors of key load-carrying components such as the cycloid gear, the pin gear and the crankshaft on the dynamic transmission accuracy are studied. Through the sensitivity analysis, a control method on the dynamic transmission accuracy of the RV reducer is proposed, which provides a theoretical support for further optimization of the transmission performance for RV reducer.
Numerical Investigation on Influence Factors of Radiation Noise of the Bridge Crane Helical Gear Reducer
Authors: Liu Wen , Gao Biao , Lin Teng-jiao , Zhang Jin-hong
Published: November 2017

In this paper, the internal dynamic excitation of the gear pair in a helical gear reducer of bridge crane is numerically investigated, taking into account of time-varying mesh stiffness, comprehensive gear error and meshing shock. The integral finite element model of bridge crane reducer gearbox is built by ANSYS software using APDL language. The internal dynamic excitations are imposed on the contact line of gear pair to solve the dynamic response of the gearbox. Using the results of dynamic response as boundary excitation conditions, the acoustic boundary element model is established. The surface sound pressure of gearbox and the radiated noise of field points are solved with SYSNOISE software. In order to verify the feasibility of the simulation method, a vibration & noise test is carried out. With the constant center distance as well as the similar total transmission ratio, the surface sound pressure of gearbox and the radiated noise of field points are calculated with different modules and helix angles. The effects of module and helix angle on the noise radiation of the gearbox are analyzed and discussed. The results provide a useful theoretical guidance for the design of gearboxes.
Kinematics and Workspace Analysis of a 3PPPS Parallel Robot With U-Shaped Base
Authors: Chablat Damien , Baron Luc , Jha Ranjan
Published: November 2017

This paper presents the kinematic analysis of the 3-PPPS parallel robot with an equilateral mobile platform and a U-shape base. The proposed design and appropriate selection of parameters allow to formulate simpler direct and inverse kinematics for the manipulator under study. The parallel singularities associated with the manipulator depend only on the orientation of the end-effector, and thus depend only on the orientation of the end effector. The quaternion parameters are used to represent the aspects, i.e. the singularity free regions of the workspace. A cylindrical algebraic decomposition is used to characterize the workspace and joint space with a low number of cells. The discriminant variety is obtained to describe the boundaries of each cell. With these simplifications, the 3-PPPS parallel robot with proposed design can be claimed as the simplest 6 DOF robot, which further makes it useful for the industrial applications.
Numerical Approximation of Basic Boundary-Contact Problems
Authors: Chumburidze Manana , Lekveishvili David
Published: November 2017

This paper is devoted to the development of approximation method for numerical solution of basic boundary-contact problems of coupled thermo-elasticity in the Green-Lindsay formulation. In particular, we consider a static system of partial differential equations for two-dimensional isotropic inhomogeneous elastic materials in assumptions that surfaces are sufficiently smooth. The tools applied in this development are based on singular integral equations, the potential method and the generalized Fourier series analysis.
Double-Layer Nerve Guide Conduit With Palisade Poly(Lactic-Co-Glycolic Acid) Tube Wrapped by Microporous Chitosan-Collagen Composite
Authors: Li Ching-Wen , Wang Gou-Jen
Published: November 2017

In this study, a double-layer nerve guide conduit (DLNGC) that comprises an inner poly(lactic-co-glycolic acid) (PLGA) scaffold with palisade structure and an outer micro-porous chitosan-collagen composite (CSC) membrane was developed. The PLGA scaffold was fabricated using the commonly used soft-lithography process and then rolled into a tube. The micro-porous CSC membrane was fabricated by lyophilization (freeze-drying), with its pore size being controlled by the chitosan:collagen weight ratio. The CSC properties such as water absorption rate, permeation rate, and biocompatibility were then measured. The CSC containing 25% chitosan (CSC-25%) has a high water absorption and permeation rates. Hence, it was adopted as the outer structure of the developed nerve conduit scaffold. After wrapping a palisade PLGA tube with a CSC-25% membrane to complete a DLNGC, mouse brain neural stem cells KT98 were injected into the inner PLGA scaffold through the pores of the outer CSC membrane. Images of biopsy samples illustrate that KT98 cells can be immobilized on the CSC-25% membrane after seven days’ culture. On the 14th day of culture, the thickness of the KT98 cells was found to have increased, and the cells were wrapped around the PLGA scaffold. The tissue section image further indicated that KT98 cells grew along the palisade structure of the PLGA scaffold.
Image Segmentation Based on Fractional Differentiation and RSF Model
Authors: Zhang Guimei , Zhu Yangang , Liu Jianxin , Chen YangQuan
Published: November 2017

Intensity inhomogeneity or weak texture region image segmentation plays an important role in computer vision and image processing. RSF (Region-Scalable Fitting) active contour model has been proved to be an effective method to segment intensity inhomogeneity. However RSF model is sensitive to the initial location of evolution curve , it tends to fall into local optimal. Aiming at the problem, this paper proposed a new method for image segmentation based on fractional differentiation and RSF model. The proposed method adds the global Grünwald-Letnikov fractional gradient into the RSF model. Thus the gradient of the intensity inhomogeneity and weak texture regions is strengthened. As a result, both the robustness of initial location of evolution curve and efficiency of image segmentation are improved. Theoretical analysis and experimental results demonstrate that the proposed algorithm is capable of segmenting the intensity inhomogeneities and weak texture images. It is robust to curve initial location, furthermore the efficiency of segmentation is improved.
Smooth Switching Design/Implementation of the Active Disturbance Rejection Control
Authors: Zhao Shen , Morris Dan , Gao Zhiqiang
Published: November 2017

Although active disturbance rejection control (ADRC) has demonstrated promising results in many applications, in some safety critical applications e.g. power plant, unmanned aerial vehicle, etc., it is often reluctant to switch from an existing control algorithm, either the traditional PID controller or other advanced control algorithms, to a new one. If the switching between the control algorithms can be made seamless, many more opportunities may open up. In this paper, the problem of making the switching to the ADRC smooth is studied. Previous attempts to solve the problem are not thorough enough, since only a second order system was addressed. A very simple and effective method is proposed based on analysis to make the transition seamless. The solution is very general, and can be applied to system of any order or even system with time-delay. At the core of the solution is the initialization of the “total disturbance”.
A Survey of Fractional-Order Neural Networks
Authors: Zhang Shuo , Chen YangQuan , Yu Yongguang
Published: November 2017

In this paper, the literature of fractional-order neural networks is categorized and discussed, which includes a general introduction and overview of fractional-order neural networks. Various application areas of fractional-order neural networks have been found or used, and will be surveyed and summarized such as neuroscience, computational science, control and optimization. Recent trends in dynamics of fractional-order neural networks are presented and discussed. The results, especially the stability analysis of fractional-order neural networks, are reviewed and different analysis methods are compared. Furthermore, the challenges and conclusions of fractional-order neural networks are given.
Extended State Observer Based Ascent Trajectory Tracking Method
Authors: Nie Wenming , Li Huifeng , Zhang Ran , Liu Bo
Published: November 2017

The ascent trajectory tracking problem of a launch vehicle is investigated in this paper. To improve the conventional trajectory linearization method which usually omits the linearization errors, the extended state observer (ESO) is employed in this paper to timely estimate the total disturbance which consists of the external disturbances and the modeling uncertainties resulting from linearization error. It is proven that the proposed trajectory tracking controller can guarantee the desired performance despite both external disturbances and the modeling uncertainties. Moreover, compared with the conventional linearization control method, the proposed controller is shown to have much better performance of uncertainty rejection. Finally, the feasibility and performance of this controller are illuminated via simulation studies.
Bifurcation Trees of Periodic Motions in a Parametrically Excited Pendulum
Authors: Guo Yu , Luo Albert C. J.
Published: November 2017

In this paper, the bifurcation trees of periodic motions in a parametrically excited pendulum are studied using discrete implicit maps. From the discrete maps, mapping structures are developed for periodic motions in such a parametric pendulum. Analytical bifurcation trees of periodic motions to chaos are developed through the nonlinear algebraic equations of such implicit maps in the specific mapping structures. The corresponding stability and bifurcation analysis of periodic motions is carried out. Finally, numerical results of periodic motions are presented. Many new periodic motions in the parametrically excited pendulum are discovered.
The Design Focused Engineering Outreach to a Middle School Using Arduino Projects
Authors: Kwon Hyun J.
Published: November 2017

Most engineering outreach programs are a part of STEM outreach efforts and they often fail to bring engineering-specific interests. We present a unique engineering outreach effort with the focus on “engineering design” with the use of Arduino UNO board. Arduino UNO board was used to achieve the design oriented learning and bring creativity through various projects targeting 7–8th graders. In order to achieve the design oriented outreach goal, several strategies were employed. The program was called “Science Art’ to provide familiar concept of design and challenge them with technology. College engineering students directly mentored 7–8th graders in a small group setting to teach technical details. In addition, the efforts were sustained for an entire quarter. It successfully drew the participants in all diverse ethnic and gender groups. The use of Arduino board project allowed development of design concepts and promoted creativity to the middle school students. Student mentees’ feedback was very positive, showing almost perfect approval. At the same time, college mentors equally benefited from the experiences by increasing interpersonal skills and gaining technical confidence. In conclusion, the close mentorship and sustained effort provided a great way to implement the Arduino based program to a middle school and thus achieve the design oriented outreach goal. This approach can be widely used for other design oriented outreach program.
Design Thinking at the Core: Learn New Ways of Thinking and Doing by Reframing
Authors: Ge Xiao , Leifer Larry
Published: November 2017

We present a theoretical framework about how designers learn new ways of thinking and doing named the reframing theory. The theory underlines why some designers’ creative behaviors endure and some not in face of a conflicting social belief system. In this paper, we first describe the problems that designers and educators face when the cultures that designers attach to and the social logics that they invoke to make sense of their practices are constantly changing. Second, we decode the phenomenon and unpack the problems by drawing on an extensive body of research on cognitive processes, learning theories, and social influences. Third, we propose a theoretical framework to denote that the key to develop and maintain enduring creative behaviors is through reconstruction of one’s perceptions. This theory-oriented paper ends by discussing future directions for educators and researchers, with the aim to advance the research and academic discussions about how to improve design ability.
Application of Nonlinear Active Disturbance Rejection Control to One-DOF Electrostatic Actuators
Authors: Kandula Prasanth B. , Dong Lili
Published: November 2017

In this paper, a non-linear active disturbance rejection controller (NADRC) is designed and originally applied to a non-linear one-degree-of-freedom electrostatic actuator (ESA). The imperfections of micro-fabrication and micro-packaging result in the modeling uncertainties of ESA. In addition, the ESA is inherently unstable due to pull-in phenomenon. So our control goal is to overcome the pull-in instability of ESA and achieve 99.99% of its full travel range despite of the presence of uncertainty. The NADRC consists of an extended state observer (ESO) and a feedback controller. Two kinds of ESOs are developed in this paper. They are high gain ESO (HG ESO) and the ESO with Fal nonlinearity (FAL ESO). The NADRC is independent of accurate model information, and therefore is a suitable controller for the uncertain ESA. The NADRCs with two different ESOs are simulated on the nonlinear ESA. A comparison study is conducted between both ESOs in terms of control performance and stability. The simulation results demonstrate the controllers with both ESOs reach our control goal successfully. While the NADRC with HG ESO generates larger control effort than the one with FAl ESO, the former is more robust against parameter variations and disturbance than the later.
Differential Gear Bending Stresses in Presence of Misalignments and Runout
Authors: Kolivand Mohsen , Sun Victor C. , Chemelli Douglas J. , Balenda Joe , Shi Zhenghong
Published: November 2017

Automotive differential gears are usually operating at very low speed and high load conditions and hence are usually designed to be protected against the root bending fatigue failure. Depending on application requirements and lubrication regime surface failures may occasionally be encountered as well. Mainstream existing design procedures published by AGMA is based on analyzing one single gear pair engagement while up to four potential engagements, between two side gears and two differential pinions, exist. There are also differential designs with three or four differential pinions that increase potential number of engagements to respectively six and eight. Usually the hypoid gear loading is divided by number of side gears, two, differential pinion loads are also usually assumed to be equal; this is a good estimate when no misalignments are present. When misalignments are present however, load sharing between the differential pinions become greatly imbalanced. This study tries to come up with a simplified analytical approach to evaluate overload factor between the differential pinions as a result of misalignments realized by differential gears inside a differential case. The total indexing runout quality of gears is also studied through treating it as a source of misalignment. This study will help designers to evaluate the effects of tolerancing limits and differential case machining errors on differential gear bending lives.
A Qualitative Survey of Reconfigurable Mechanisms With Industrial Applications
Authors: Buchta Anthony J. , Voglewede Philip A.
Published: November 2017

In the field of reconfigurable mechanisms, many ingenious designs have been built and analyzed, however very few have been implemented in industry. An analogous comparison of reconfigurable mechanisms to James Watt’s straight line mechanism is explored to suggest as to why there is a shortage of reconfigurable mechanisms being used. A qualitative survey was undertaken to examine existing mechanisms currently being used and to identify potential applications for reconfigurable mechanisms. Eleven manufacturing plants were visited to identify high frequency motion profiles. From this survey, motion profiles were selected for potential applications of reconfigurable mechanisms. One of the motion profiles, platform transfer, was selected from a possible four identified motion profiles. A proposed reconfigurable mechanism was designed to perform the platform transfer task. The joint of the mechanism consists of two R2P2 joints connected by a P2 joint.
Energy-Efficient Trajectory Planning for Robot Manipulators
Authors: Lorenz Michael , Paris Jascha , Schöler Frederic , Barreto Juan-Pablo , Mannheim Tom , Hüsing Mathias , Corves Burkhard
Published: November 2017

Automated object manipulation is subject to various constraints, which can be affected by means of suitable motion strategies. With respect to an efficient motion design corresponding strategies are often referred to the manipulator’s energy consumption and performance considering its specified kinematic and dynamic characteristics. Supposing that various automated manufacturing processes use industrial robots and manipulators, an efficient motion design is able to reduce operating costs and CO2 emissions.

This contribution is devoted to the simulation based energy optimization of robot motions, considering both the geometric path and the motion law of specific trajectories. In this context, two different levels of trajectory optimization are suggested, exposing the displacement of geometric nodes on the one hand and the variation of velocities and accelerations on the other hand. Due to its simple kinematic structure, the analyses exemplarily are focused on different trajectories of the manipulator Re-PlaLink, a five-bar linkage, which is capable of energy recuperation during regenerative mode. Accordingly, results show a significant energy reduction, establishing high potentials for an increased efficiency of industrial robots.
Period-3 Motions in a Periodically Forced, Damped, Double-Well Duffing Oscillator With Time-Delay
Authors: Luo Albert C. J. , Xing Siyuan
Published: November 2017

In this paper, period-3 motions in a double-well Duffing oscillator with time-delay are predicted by a semi-analytical method. The implicit mapping structures of period-3 motions are constructed through the implicit mappings obtained by discretization of the corresponding differential equation. Complex period-3 motions are predicted through nonlinear algebraic equations of the implicit mappings in the mapping structures and the corresponding stability and bifurcation are carried out through eigenvalue analysis. Numerical and analytical results of complex period-3 motions are obtained and the corresponding frequency-amplitude characteristics are presented.
A Virtual Bearing Method for Optimal Bearing Placement of Flexible Rotor Systems
Authors: Liu Shibing , Yang Bingen
Published: November 2017

Flexible multistage rotor systems have a variety of engineering applications. Vibration optimization is important to the improvement of performance and reliability for this type of rotor systems. Filling a technical gap in the literature, this paper presents a virtual bearing method for optimal bearing placement that minimizes the vibration amplitude of a flexible rotor system with a minimum number of bearings. In the development, a distributed transfer function formulation is used to define the optimization problem. Solution of the optimization problem by a real-coded genetic algorithm yields the locations and dynamic coefficients of bearings, by which the prescribed operational requirements for the rotor system are satisfied. A numerical example shows that the proposed optimization method is efficient and accurate, and is useful in preliminary design of a new rotor system with the number of bearings unforeknown.
Process Design and Control Method of Laser Via Hole Drilling of Printed Wiring Boards Based on High Speed Camera Monitor
Authors: Kanki Koji , Hirogaki Toshiki , Aoyama Eiichi , Ogawa Keiji
Published: November 2017

In recent years, the performance and miniaturization of portable information devices have rapidly advanced. The build-up process is often used in the manufacturing of printed wiring boards (PWBs) for high-density circuits. At present, CO2 laser beams are generally used in the build-up process to drill blind via holes (BVHs) that connect copper foils. The Cu direct-laser method is often used in this process, which irradiates laser to drill the copper foil and insulation layer simultaneously. Cu direct-laser involves a complex phenomenon because it drills copper and resin, with different decomposition points, at the same time. However, only few studies have been made in this field. This report focuses on monitoring Cu direct-laser drilling with a high-speed camera. We drilled holes with four different laser power outputs, 25 W, 50 W, 75 W, and 95 W and measured the size of the drilled holes. During the drilling process, the camera captured the emission of scattering materials in the PWBs. We have processed the images obtained from the camera to observe the scattering material. As a result, we found out that changes in the amount of scattering occur on four occasions: when the outer copper foil is drilled through, when the drilled depth reaches the inner copper foil, when the increase rate of the hole diameter is reduced, and when the inner copper foil is drilled through. Based on these results, the suitable laser irradiation time can be determined for different drilling conditions.
Nonlinear Modal Interactions of a Parametrically Excited Composite Column
Authors: Warminski Jerzy , Teter Andrzej
Published: November 2017

Nonlinear dynamics of a composite column loaded by axial periodic force is presented in the paper. The simply supported channel column is made of several layers of a laminate with an general arrangement, leading to mechanical deformation couplings. A reduced model of the column is represented by a set of nonlinear equations which includes geometric nonlinear terms and parametric excitation. For the selected configuration of the composite structure parametric instability zones and vibration modes coupling occur. In contrast to isotropic materials, a modification of the reinforcing fibres layout results in a change of structure dynamic properties and a location of parametric resonance zones. Furthermore, buckling phenomenon may occur through various scenarios, by the global or local mode activation. The effect of the composite configuration on the principal parametric resonance zones is presented.
Parametric Shape and Topology Optimization: A New Level Set Approach Based on Cardinal Kernel Functions
Authors: Jiang Long , Chen Shikui , Jiao Xiangmin
Published: November 2017

The parametric level set method is an extension of the conventional level set methods for topology optimization. By parameterizing the level set function, conventional levels let methods can be easily coupled with mathematical programming to achieve better numerical robustness and computational efficiency. Furthermore, the parametric level set scheme not only can inherit the original advantages of the conventional level set methods, such as clear boundary representation and high topological changes handling flexibility but also can alleviate some un-preferred features from the conventional level set methods, such as needing re-initialization. However, in the RBF-based parametric level set method, it was difficult to determine the range of the design variables. Moreover, with the mathematically driven optimization process, the level set function often results in significant fluctuations during the optimization process. This brings difficulties in both numerical stability control and material property interpolation. In this paper, an RBF partition of unity collocation method is implemented to create a new type of kernel function termed as the Cardinal Basis Function (CBF), which employed as the kernel function to parameterize the level set function. The advantage of using the CBF is that the range of the design variable, which was the weight factor in conventional RBF, can be explicitly specified. Additionally, a distance regularization energy functional is introduced to maintain a desired distance regularized level set function evolution. With this desired distance regularization feature, the level set evolution is stabilized against significant fluctuations. Besides, the material property interpolation from the level set function to the finite element model can be more accurate.
Optimization of Origami-Based Tubes for Lightweight Deployable Structures
Authors: Yellowhorse Alden , Tolman Kyler , Howell Larry L.
Published: November 2017

Tubular origami may provide both the needed deployment displacement and sufficient strength to be useful as deployable structures. This paper reviews origami tube-based deployable mechanisms and a structural optimization of FEA models is performed. Symmetric and non-symmetric 4-sided tubes are evaluated. Panel geometries and thicknesses are varied to produce rigidly foldable origami-tube-based mechanisms that are both strong and lightweight. The mechanical properties of these tubes over various deployment lengths are discussed. Three different configurations of this mechanism are compared and the advantages of each are discussed.
Improvement of Harvesters for Tires by Means of Multi-Physics Simulation
Authors: Doria Alberto , Medè Cristian , Desideri Daniele , Maschio Alvise , Moro Federico
Published: November 2017

The specific working conditions of piezoelectric harvesters for scooter tires are analyzed. Calculated and experimental results show that the excitation of the harvester can be considered a series of separated impulses. Harvester response to an ideal impulse is analyzed with a single-mode model. An optimal ratio between impulse duration and natural period of the harvester that maximizes harvester excitation is found. A numerical finite element (FE) model of a bimorph cantilever harvester is developed in COMSOL and validated by means of experimental tests. The validated FE model is used for showing that an actual harvester excited by road impulses generates a large voltage only if there is a specific relation between impulse duration and natural period of the harvester. Starting from the validated FE model, small harvesters suited to tires are developed and analyzed. Also these harvesters show the best performance for a specific range of impulse durations, which corresponds to the highest speeds of the speed range of the scooter (50–80 km/h) and to high levels of acceleration.
Design and Analysis of a New Type Forging Manipulator
Authors: Li Yanwen , Shi Xiaofei , Mao Pengfei , Cai Yubo , Wang Maoling
Published: November 2017

Large-scale forging manipulator is the indispensable equipment in the operations of automated forging. Because of the increasing demand of forging manipulator, large and medium-sized enterprises pay more and more attention to the forging operation in production. Lower freedom parallel mechanism is obtained by using the constraint-synthesis method based on the screw theory, then a mechanism of forging manipulator is designed including raising and lowering, pitching, lateral swing, lateral movement, forth or back and clamp rotation. The new type forging manipulator is a hybrid serial-parallel mechanism. The degree of freedom of the parallel mechanism is calculated by using the modified Grübler-Kutzbach criterion, and then the degree of freedom of the machine is determined. Through closed geometric method, the kinematic position analysis is performed, and the correctness of the theoretical analysis results is verified.
Reliability of Nonlinear Vibratory Systems Under Non-Gaussian Loads
Authors: Geroulas Vasileios , Mourelatos Zissimos P. , Tsianika Vasiliki , Baseski Igor
Published: November 2017

A general methodology is presented for time-dependent reliability and random vibrations of nonlinear vibratory systems with random parameters excited by non-Gaussian loads. The approach is based on Polynomial Chaos Expansion (PCE), Karhunen-Loeve (KL) expansion and Quasi Monte Carlo (QMC). The latter is used to estimate multi-dimensional integrals efficiently. The input random processes are first characterized using their first four moments (mean, standard deviation, skewness and kurtosis coefficients) and a correlation structure in order to generate sample realizations (trajectories). Characterization means the development of a stochastic metamodel. The input random variables and processes are expressed in terms of independent standard normal variables in N dimensions. The N-dimensional input space is space filled with M points. The system differential equations of motion are time integrated for each of the M points and QMC estimates the four moments and correlation structure of the output efficiently. The proposed PCE-KL-QMC approach is then used to characterize the output process. Finally, classical MC simulation estimates the time-dependent probability of failure using the developed stochastic metamodel of the output process. The proposed methodology is demonstrated with a Duffing oscillator example under non-Gaussian load.
Dynamic Transmission Error Measurements From Spur Gear Pairs Having Tooth Indexing Errors
Authors: Anichowski Brian , Kahraman Ahmet , Talbot David
Published: November 2017

This paper complements recent investigations [Handschuh et al (2014), Talbot et al (2016)] of the influences of tooth indexing errors on dynamic factors of spur gears by presenting data on changes to the dynamic transmission error. An experimental study is performed using an accelerometer-based dynamic transmission error measurement system incorporated into a high-speed gear tester to establish baseline dynamic behavior of gears having negligible indexing errors, and to characterize changes to this baseline due to application of tightly-controlled intentional indexing errors. Spur test gears having different forms of indexing errors are paired with a gear having negligible indexing error. Dynamic transmission error of gear pairs under these error conditions is measured and examined in both time and frequency domains to quantify the transient effects induced by these indexing errors. Both measurements indicate clearly that the baseline dynamic response, dominated by well-defined resonance peaks and mesh harmonics, are complemented by non-mesh orders of transmission error due the transient behavior induced by indexing errors.
Object Recognition and Pose Estimation Based on Combined Use of Projection Histograms and Surface Fitting
Authors: Ahola Jari M. , Heikkilä Tapio
Published: November 2017

In this paper we present a configurable object recognition and locating system for 3D point cloud sensors. The objects are recognized based on cylindrical projection histograms and after the object is recognized, the initial pose of the object is computed based on the eigenvectors of the modelled and measured 3D point clusters. The optimal 6 degree of freedom pose is estimated by fitting the CAD-model surfaces to the measured 3D-points, where the model surfaces and 3D points are correlated based on the modelled and measured eigenvectors. The novelty of our system is the combination of reliable histogram based object recognition and accurate CAD-based pose estimation in the object recognition system with configurability options according to application requirements and point cloud properties.
Developing a Kinematically Similar Master Device for Extensible Continuum Robot Manipulators
Authors: Frazelle Chase G. , Kapadia Apoorva , Walker Ian
Published: November 2017

We introduce a novel input device for the teleoperation of extensible continuum robots. As opposed to previous works limited by kinematically dissimilar master devices or restricted Degrees-of-Freedom (DoF), a kinematically similar input device capable of nine degrees-of-freedom is designed and used. The device is capable of achieving configurations identical to a three-section continuum robot and simplifies the control of such manipulators. In this paper, we outline the design of the input device and its construction. Implementation of the new master device and its effectiveness in regulating a physical system is also discussed.
Variational Analysis of a Two Link Slider-Crank Mechanism Using Polynomial Chaos Theory
Authors: Ryan Paul S. , Baxter Sarah C. , Voglewede Philip A.
Published: November 2017

Variation occurs in many closed loop multi-body dynamic (MBD) systems in the geometry, mass, or forces. Understanding how MBD systems respond to variation is imperative for the design of a robust system. However, simulation of how variation propagates into the solution is complicated as most MBD systems cannot be simplified into to a system of ordinary differential equations (ODE). This paper investigates polynomial chaos theory (PCT) as a means of quantifying the effects of uncertainty in a closed loop MBD system governed by differential algebraic equations (DAE). To demonstrate how PCT could be used, the motion of a two link slider-crank mechanism is simulated with variation in the link lengths. To validate and show the advantages and disadvantages of PCT in closed loop MBD systems, the PCT approach is compared to Monte Carlo simulations.
Quantifying the Mismatch Between Course Content and Students’ Dialogue in Online Learning Environments
Authors: Lim Sunghoon , Tucker Conrad S. , Jablokow Kathryn , Pursel Bart
Published: November 2017

Due to the internet’s increasing global availability, online learning has become a new paradigm for distance learning in higher education. While student interactions and reactions are readily observable in a physical classroom environment, monitoring student interactions and quantifying divergence between lecture topics and the topics that interest students are challenging in online learning platforms. Understanding the effects of this divergence is important for monitoring student engagement and aiding instructors, who are focused on improving the quality of their online courses. The authors of this paper propose a topic modeling method, based on latent Dirichlet allocation (LDA), that quantifies the effects of divergence between course topics (mined from textual transcriptions) and student-discussed topics (mined from discussion forums). Correlations between the measured dissimilarities and (a) the number of posts and comments in discussion forums, (b) the number of submitted assignments, and (c) students’ average performance scores are presented. A case study involving video lecture transcripts and discussion forum posts/comments in a massive open online course (MOOC) platform demonstrates the proposed method’s potential success and informs course providers about the challenges of measuring the topics that interest students.
Optimization for Large or Linear Tunable Stiffness Control With a Concentric Circular Tapered Beam Design
Authors: Johnson Shane , Van Beek Anton , Qaiser Zeeshan , Kang Liping
Published: November 2017

Most examples of structure controlled Tunable Stiffness Mechanisms (TSM) systems have two predefined settings of stiffness, e.g. bi-stiffness behavior, or they have a low range in tunable stiffness. In this research, this problem of control is overcome though optimization of a novel concentric circular tapered spring beam design with the novel design concept of changing the mode of deformation from bending to axial or shear. A Monte Carlo (MC) function is used with an analytical model — the unit load method of virtual work, to determine the optimum shape of two concentric tapered beams where the minimum stiffness is set, and the objective is to achieve linear and/or large stiffness change control. Three optimum designs were 3D printed, tested, and the stiffness vs. loading angle of control was validated with excellent correlation. The optimum design was obtained by changing the dominant loading modes.
Postural Balance of an Underactuated Biped Robot With a Reaction Wheel
Authors: Maurice Chris M. , Goodwine Bill , Schmiedeler James P.
Published: November 2017

Practical and effective biped robots are trending toward reality with increasing interest in the technology and recent major innovations in nonlinear control theory. The development of underactuated techniques transitioned biped robot walking to a more elegant human-like motion. When disturbances are encountered, maintaining postural balance becomes a proven challenge that limits the practicality of these machines. This paper offers a solution to this issue by showing that an underactuated five-link reaction wheel-equipped planar biped robot can be posturally balanced successfully and efficiently with feedback control laws derived from the system’s zero dynamics and through task space optimization. The zero dynamics controller is shown to exhibit better performance compared to the task space controller in terms of settling time and total system work.
An Agent-Based Market System Simulation for Design Education
Authors: Fay Brendan E. , Hoffenson Steven
Published: November 2017

In product design, there is often a disconnect between the engineers creating the product and the marketing team determining the best characteristics for the product. The decisions of engineers in designing a product, such as dimensions, materials, and tolerances, affect the look and feel of the product as seen by the consumer. This paper presents a methodology for creating a simulation to demonstrate basic relationships between product design decisions and the predicted success of the product in the market. An agent-based model is used to simulate the interactions among producers and consumers in a market system, using analysis techniques from engineering, economics, and psychology. The effects of design variables on product attributes influence the cost and consumer utility of the product, which, along with price, affect market dynamics. The goal of creating this model is for use in design curricula to introduce the concept of market-driven product design and allow student design teams to assess the impacts of different design variables on the market success of a product. The model has been introduced in an undergraduate engineering design class to explore its effectiveness in teaching market-driven design.
Frequency Response of Parametric Resonance of Double Wall Carbon Nanotube Under Electrostatic Actuation
Authors: Caruntu Dumitru I. , Juarez Ezequiel
Published: November 2017

This paper deals with electrostatically actuated Double Walled Carbon Nanotubes (DWCNT) cantilevered resonators. The governing equations for the motion of the DWCNT are derived through Euler-Bernoulli beam model assumptions that account for inertial and viscoelastic effects. The DWCNT is a specific type of multi-walled carbon nanotube (MWCNT) that is comprised of two coaxially concentric carbon nanotubes. Electrostatic, damping, and intertube van der Waals forces act on the outer tube of the DWCNT, while only intertube van der Waals force acts on the inner tube. A soft AC voltage provides the electrostatic actuation. The nonlinear behavior and phenomena in the system are provided by the electrostatic and intertube van der Waals forces. The DWCNT is subjected to nonlinear parametric dynamics. The Method of Multiple Scales (MMS) is employed to investigate the system under soft excitations and/or weak nonlinearities. The frequency-amplitude response is found in the case of parametric resonance. The resulting nonlinear dynamic behavior is important to improve DWCNT resonator sensitivity in the application of mass sensing.
Analyzing Composite Material Manufacturing Methods Using Failure Modes Effect Analysis
Authors: Kames Elisabeth , Zaremba Ryan , Morkos Beshoy
Published: November 2017

This paper presents the preliminary results of a case study of Failure Modes and Effects Analysis (FMEA) in composite manufacturing. The purpose of FMEA is to improve quality, reliability, safety, durability, and reduce product life-cycle costs. Six various methods of composite layup (both manual and automated) were identified and examined with respect to various defect types caused through the composite layup process such as porosity, fiber misalignment, excess or insufficient resin, and incomplete curing. An adaptation of FMEA for composite manufacturing was used to analyze the different defect types, and the occurrence, severity, and detectability of each type of failure in each of the composite manufacturing processes. Failure was defined as the loss of function or ability to perform a prescribed task in a given manner for which that part was designed [1]. The conclusions of this study are two-fold: design engineers can analyze the most common composite material defects in order to build robustness into the product and the methodologies used can assist process improvement for manual or automated composite manufacturing.
Efficient Reduced-Order Modeling and Response Approximation for Cracked Structures
Authors: Tien Meng-Hsuan , Hu Tianyi , D’Souza Kiran
Published: November 2017

Analysis of the influence of cracks on the dynamics of structures is critical for design, failure prognosis, and structural health monitoring. Predicting the dynamics of complex cracked structures is computationally challenging for two reasons: (1) the model size is generally large, and (2) the piecewise-linear nonlinearity caused by contact eliminates the use of linear analysis tools. Recently, a technique referred to as X-Xr approach was developed to efficiently reduce the model size of cracked structures. The method employs relative coordinates to describe the motion of crack surfaces such that an effective model reduction can be achieved using Craig-Bampton component mode synthesis. More recently, a method referred to as the generalized bilinear amplitude approximation (generalized BAA) was developed to approximate the amplitude and frequency of piecewise-linear nonlinear systems. This paper modifies the generalized BAA method and combines it with the X-Xr approach to efficiently predict the dynamics of complex cracked structures. The combined method is able to estimate the amplitude and frequency of cracked systems with a reduced computational effort. The proposed approach is demonstrated on a three degree of freedom spring-mass system and a cracked cantilever beam.
Parametric Excitation of a Repulsive Force Actuator
Authors: Pallay Mark , Towfighian Shahrzad
Published: November 2017

Parametric resonances in a repulsive-force MEMS resonator are investigated. The repulsive force is generated through electrostatic fringe fields that arise from a specific electrode configuration. Because of the nature of the electrostatic force, parametric resonance occurs in this system and is predicted using Mathieu’s Equation. Governing equations of motion are solved using numerical shooting techniques and show both parametric and subharmonic resonance at twice the natural frequency. The primary instability tongue for parametric resonance is also mapped. This is of particular interest for MEMS sensors that require high signal-to-noise ratios due to the large oscillation amplitudes associated with parametric resonance.
Real-Time Modeling to Enable Hardware-in-the-Loop Simulation of Plug-In Electric Vehicle-Grid Interaction
Authors: Cao Chong , Wang Luting , Chen Bo , Harper Jason , Bohn Theodore , Dobrzynski Daniel , Hardy Keith
Published: November 2017

Real-Time simulation and Hardware-in-the-Loop (HIL) testing are increasingly adopted by industry for the development and validation of complex systems. This paper presents the real-time modeling and power management of a Vehicle-Grid Integration (VGI) system. The VGI system consists of six AC level 2 Plug-in Electric Vehicle (PEV) charging stations, a Photovoltaics (PV) farm, a commercial building load, and a switch connecting to 240V single phase power grid. PEV charging activities follow the SAE J1772 standard. An energy management algorithm is designed for the VGI system to coordinate the PEV charging with the building load and PV renewable generation. The coordination maintains the power consumption of the VGI system below utility’s demand charge pricing threshold. A real-time power system simulator, Opal-RT, is used in this study. The OPAL-RT system allows users to build detailed power system models using Matlab Simulink/SimPowerSystems and RT-LAB library, and run the models in real-time. The model-based approach enables the integration of power system models seamlessly with the power management algorithm and power electronics-level controllers. The simulation results show that the VGI model emulates the real system well and the coordinated PEV charging helps to balance the power generation and consumption of the VGI system to meet power management requirement.
Closed-Loop Design for Hybrid Powertrains
Authors: Vanhuyse Johan , Murgovski Nikolce , Nicolai Mike , Van der Auweraer Herman , Desmet Wim
Published: November 2017

The increasing interest into hybrid electric vehicles imposes the need to provide computational support for design choices during the development of these vehicles. This paper presents the use of a new methodology which allows for automatically generating topologically different hybrid powertrain concepts, and evaluating their performance. Since the energy management controller plays an important role in the performance assessment, a modular framework based on optimal control theory is used for assessing the closed-loop performance of different hybrid powertrain architectures. This paper illustrates how the concept generation methodology can be combined with optimal control in order to compare the closed-loop performance of a series and parallel hybrid powertrain.
Methods for Protection of Intellectual Property in Embedded Linux: A Survey
Authors: Gerstmayer Florian , Hausladen Jürgen , Kramer Michael , Horauer Martin
Published: November 2017

Embedded systems technologies are at the core of many products and applications, for example, ones as used in smart homes or modern cars. These technologies enable new functional features which in turn improve also non-functional aspects such as environmental efficiency. Especially, their inter-connection and coupling with existing networks — here in particular to the internet — allows for an unprecedented boost. At the same time security concerns become consequential since respective security breaches may have dire consequences that range from theft and/or tampering of intellectual property over to malfunctions that can result in threats of safety. This paper presents a survey of software approaches used to prevent reverse engineering, defend against malicious modifications, and to ensure integrity of embedded systems software. The presented methods focus on mechanisms for post development stages that can be used to add/improve security features of existing products. Furthermore, different kind of targets are taken into consideration, separating the introduced security features in regard to their applicability for standalone and OS-based embedded systems.