bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multidisciplinary Framework to Model Complex Team-Based Product Development
Authors: Takai Shun
Published: January 2016

This paper investigates a multidisciplinary framework that simulates design decisions in a complex team-based product development in which engineers simultaneously work in a team project and individual projects. The proposed framework integrates cooperative and noncooperative design models with (1) equilibrium analysis, (2) uncertainty modeling based on behavioral game-theory results, and (3) decision-making using decision analysis. In the proposed framework, noncooperative design is used to simulate engineers’ decisions about team project commitment and to analyze potential free-riding; cooperative design is used to model design outcomes when engineers collaborate in the team project; equilibrium analysis and behavioral game-theory results are used to infer about other engineers’ decisions; and decision analysis is used to calculate expected values of decision alternatives. The proposed framework and the design decision-making model are illustrated using a pressure vessel design as a team project conducted by two engineers: a design engineer and a materials engineer.
Research on Surrogate Model Based on Local Radial Point Interpolation Method
Authors: Wang Rongqiao , Mao Jianxing , Hu Dianyin
Published: January 2016

In order to increase the accuracy of surrogate models in structural reliability analysis, we put forward a kind of surrogate model based on local radial point interpolation method (LRPIM). Three kinds of radial basis function (RBF) are employed for the shape function construction to form different kinds of LRPIM model.

In order to illustrate the approximating ability of each surrogate model, we build up a nonlinear function model and carry out a numerical experiment on gas turbine disk’s estimated life-span. Compared with polynomial model, Chebyshev orthogonal polynomial model, Kriging model and RBF neural network model, LRPIM model has a demonstrable difference in terms of accuracy. For different polynomial basis order with constant sampling nodes amount, we conclude that fluctuant accuracy can be described by the balance between the describing improvement brought by polynomial basis order increase and the local impairment brought by support domain expansion. For sampling nodes amount with constant polynomial basis order, we conclude that accuracy of LRPIM model improves when sampling nodes amount increases.

In order to illustrate the potential in reliability analysis, we apply the best performing LRPIM model to a set of widely used test problems, which certifies the accuracy and robustness of this kind of surrogate model.

In a word, LRPIM model is one of the most promising surrogate models compared with other models on nonlinear approximating problems and reliability analysis.
Saturation Optimization of Selective Waste Collection Vehicles Based on Real-Time Info-Communication System
Authors: Titrik Adam , Lakatos Istvan , Czegledi David
Published: January 2016

New technology trends are spreading in selective waste collection, which apply real-time based info-communication systems defining the saturation of the containers. Merely defining the routes to containers is not enough; saturation of the waste gathering vehicle should also be measured for optimization. In practice, the compression scale of homogenous recyclable waste types is different meaning that saturation optimization cannot be based on this value. This study aims to provide answers to the above-mentioned problem. In order to have an extended analysis the whole city traffic should be taken into account as waste collection traffic may be obstructed by traffic itself. The RPC (Route Planning Center) will apply optimal control for the entire traffic network, which is elaborated by a network analyst pre-calculating network state parameters. The extended approach is based on a determined complex road network modelling technique. Thus further research will be able to integrate the circumstances of the entire traffic network like the definition of traffic network dependent optimal trajectory in chapter 8.
Metamorphic Hand Based Grasp Constraint and Affordance
Authors: Wei Guowu , Sun Jie , Zhang Xinsheng , Pensky Dirk , Piater Justus , Dai Jian S.
Published: January 2016

This paper presents the kinematics and grasp constraint and affordance of a newly designed mobile manipulator with a three-fingered metamorphic robotic hand. Structure design of the mobile manipulator, which contains a Robotino 3.0, a customised robot arm and a three-fingered metamorphic hand, is presented. Using mechanism decomposition, kinematics of the manipulator is formulated based on product-of-exponentials method and kinematics of the metamorphic hand is investigated leading to the construction of grasp constraint providing theoretical background for measuring grasp quality of the grasps predicted by the grasp-affordance model. Further, relation of the grasp-affordance model to the manipulator and hand kinematics with the associated grasp constraint are indicated linking the manipulator kinematics with the grasp-affordance model for object manipulation. The mobile manipulator proposed in this paper is to be used for toys tidying up in a child’s room with extended applications to the field of service robot in clutter clearing.
Effect of the Shape of Inlet Oil-Supply Layer on Starved Lubrication Performance of a Cycloid Drive
Authors: Zhu Caichao , Sun Zhangdong , Liu Huaiju , Song Chaosheng , Li Zufeng , Wang Zi
Published: January 2016

The lubrication performances of cycloid drives affect the dynamic characteristics, the mechanical efficiency and the contact fatigue behavior of the system. To maintain tranmission precision it is required to minimum the times of disassebly, hence grease lubrication is often applied where starvation might occur in service. Starved lubrication performance of a cycloid gear drive is studied using a numerical finte line starved-elastohydrodynamic lubrication model. The parameter of the inlet oil film thickness is chosen to represent the starved status. Effects of the inlet film thickness on the centralfilm thickness, the friction coefficient and the frictional power loss are investigated. In addition, effects of different shape of inlet oil-supply layer in the same starved degree on lubrication performance are studied. Under the same inlet oil supply volume, the convex type profile would present a better oil film within the nominal contact zone compared with other four different shapes of the inlet film supply.
The Effects of Elaboration in Creativity Tests as it Pertains to Overall Scores and How it Might Prevent a Person From Thinking of Creative Ideas During the Early Stages of Brainstorming and Idea Generation
Authors: Dippo Caitlin , Kudrowitz Barry
Published: January 2016

Previous studies have found that the first few ideas we think of for a given prompt are likely to be less original than the later ideas. In this study, 460 participants were given the Alternative Uses Test (AUT) where they were asked to list alternative uses for a paperclip, creating a database of 235 unique answers, each having a relative occurrence rate in that pool. It was found that later responses were significantly more novel than early responses and on average the originality of responses exponentially increased with quantity. A closer look at this data reveals that a person is likely to have a lower overall originality score if he or she has more elaborate responses. 89 of these participants were also given the Abbreviated Torrance Test For Adults (ATTA) and the data from both tests was used to study relationships between elaboration, fluency, and originality. The data from the AUT reveals a strong negative correlation between an individual’s average number of words per response and his or her average originality score. It is hypothesized that people who spend more time writing multiple-word responses have less time to generate many different ideas thus hindering their ability to reach the novel ideas. Similarly, the ATTA reveals that after two extraneous details, elaboration on a drawing will negatively impact fluency and originality scores. This is not to say that elaborate ideas cannot be original, but rather that in time-limited situations, elaboration may hinder the production of original ideas. In applying this to real world problem solving and idea generation, it is suggested that people may prevent themselves from finding creative solutions if too much time is spent on discussing the first few suggested ideas from a brainstorming session. It is suggested that a more effective brainstorming session will delay discussion until a significant number of ideas are generated.
Research on Tooth Profile Modification of the Herringbone Planetary Gear Train
Authors: Bao Heyun , Liu Huan , Zhu Rupeng , Lu Fengxia , Li Miaomiao
Published: January 2016

A bending-torsional coupled nonlinear dynamic model which contains the modification parameters of herringbone planetary gear train is presented. A formula of modification incentive is analyzed and deduced. The impact of the straight line and parabolic modification parameters on the amplitude of system transmission error is researched. The optimum modification parameters are acquired according to the minimum amplitude of system transmission error. Different amplitudes of the system transmission error, before and after modification, are compared at different rotational speed. The results indicate that the straight line modification parameters on the amplitude of system transmission error are more sensitive. Modification parameters on the amplitude of system transmission error are researched. When the length of the modification is specified, the amplitude of system transmission error is reduced sharply at first, then increased rapidly with the maximum magnitude of the modification increasing; When the maximum magnitude of the modification is specified, the amplitude of system transmission error is increased weakly at first, then decreased sharply, and increased rapidly in the end, with the length of the modification increasing. The modification parameters could form a crescent-shaped zone which can reduce the system transmission error amplitude significantly. The amplitudes of the system transmission error with modification are all reduced at different rotational speed, especially when there is a sympathetic vibration.
The Wave Finite Element Method Applied to a One-Dimensional Linear Elastodynamic Problem With Unilateral Constraints
Authors: Yoong Carlos , Thorin Anders , Legrand Mathias
Published: January 2016

The Wave Finite Element Method (WFEM) is implemented to accurately capture travelling waves propagating at a finite speed within a bouncing rod system and induced by unilateral contact collisions with a rigid foundation; friction is not accounted for. As opposed to the traditional Finite Element Method (FEM) within a time-stepping framework, potential discontinuous deformation, stress and velocity wave fronts are accurately described, which is critical for the problem of interest.

A one-dimensional benchmark with an analytical solution is investigated. The WFEM is compared to two time-stepping solution methods formulated on a FEM semi-discretization in space: (1) an explicit technique involving Lagrange multipliers and (2) a non-smooth approach implemented in the Siconos package. Attention is paid to the Gibb’s phenomenon generated during and after contact occurrences together with the time evolution of the total energy of the system.

It is numerically found that the WFEM outperforms the FEM and Siconos solution methods because it does not induce any spurious oscillations or dispersion and diffusion of the shock wave. Furthermore, energy is not dissipated over time. More importantly, the WFEM does not require any impact law to close the system of governing equations.
Unstable Oscillations and Wave Propagation in Flagella
Authors: Bayly Philip V. , Wilson Kate S.
Published: January 2016

Flagella are active, beam-like, sub-cellular organelles that use wavelike oscillations to propel the cell. The mechanisms underlying the coordinated beating of flagella remain incompletely understood despite the fundamental importance of these organelles. The axoneme (the cytoskeletal structure of flagella) consists of microtubule doublets connected by passive and active elements. The motor protein dynein is known to drive active bending, but dynein activity must be regulated to generate oscillatory, propulsive waveforms. Mathematical models of flagella motion generate quantitative predictions that can be analyzed to test hypotheses concerning dynein regulation. Here we investigate the emergence of unstable modes in a mathematical model of flagella motion with feedback from inter-doublet separation (the “geometric clutch” or GC model). The unstable modes predicted by the model may be used to critically evaluate the underlying hypothesis. The least stable mode of the GC model exhibits switching at the base and robust base-to-tip propagation.
A Modified Model for Non-Linear Fatigue Damage Accumulation With Load Interaction Effects
Authors: Peng Zhaochun , Huang Hong-Zhong , Gao Huiying , Lv Zhiqiang , Zhu Shun-Peng
Published: January 2016

In the case of variable amplitude loading, fatigue damage accumulation theory is closely related to loading histories, such as load sequences, load interactions, and so on. Due to the lack of load histories, there may be a large deviation with the reality for linear damage rule (Miner rule). Although many non-linear fatigue damage accumulation models can deal with the effect of load sequences, load interaction effect cannot be ignored and it plays an important role in damage accumulation behavior. This paper describes the damage evolution behavior based on nonlinear damage rule under variable amplitude loading. A new method to describe the load interaction effects is proposed, it is assumed that the load ratio between adjacent stress levels is used to present this phenomenon. Thereafter, the method is introduced to a non-linear damage model, and a modified model is developed to predict the residual lifetime. Four categories of experimental data sets from literatures are employed to investigate the validity of the proposed model. The results indicate that the modified model shows a good agreement between experimental data and theoretical results. It is also found that the modified model demonstrates an improvement in prediction accuracy over the primary model and Miner rule. Furthermore, the modified model can be easily implemented with the use of Wöhler curve only.
Comprehensive Evaluation of Parallel Mechanism and Robot Performance Based on Principal Component Analysis and Kernel Principal Component Analysis
Authors: Li Liming , Zhao Jing
Published: January 2016

Revealing the relations among parallel mechanism and robot comprehensive performance, topological structure and dimension is the basis to optimize mechanism. Due to the correlation and diversity of the single performance indexes, statistical principles of linear dimension reduction and nonlinear dimension reduction were introduced into comprehensive performance analysis and evaluation for typical parallel mechanisms and robots. Then the mechanism’s topological structure and dimension with the best comprehensive performance could be selected based on principal component analysis (PCA) and kernel principal component analysis (KPCA) respectively. Through comparing the results, KPCA could reveal the nonlinear relationship among different single performance indexes to provide more comprehensive performance evaluation information than PCA, and indicate the numerical calculation relations among comprehensive performance, topological structure and dimension validly.
Development of Impedance Control for Human/Robot Interactive Handling of Heavy Parts and Loads
Authors: Ahola Jari M. , Koskinen Jukka , Seppälä Tuomas , Heikkilä Tapio
Published: January 2016

This paper introduces a control system for human/robot interactive handling of heavy parts and loads. The aim of the study was to demonstrate the feasibility of human/robot cooperative handling of heavy parts and loads with a robot as a load carrier and a human as a motion guide. The control system included a medium sized industrial robot and two 6-dof F/T sensors adjusting the robot motion via parallel impedance compensators. This paper shows the principles for designing stable impedance compensators for hard contact with the environment as well as for soft contact with the human operator. The impedance compensators were evaluated in MATLAB Simulink and the target impedance models were verified with the real robot system. The result was a pilot system for flexible handling of heavy and large-size parts which can substantially improve the production performance and ergonomic work conditions in mechanical and manufacturing shops.
Development of Grooving Technique for Origami-Forming
Authors: Nguyen Hoan Thai Tat , Terada Kousuke , Tokura Sunao , Hagiwara Ichiro
Published: January 2016

Recently, a new manufacturing method called Origami-forming is developed, based on traditional Origami approach. In particular, the new method follows the same steps as Origami, applying for wider rank of material (soft and hard material such as aluminum, high tensile steel, etc), and folding by a reconfigurable robot system. This method is suitable for high-variety low-volume, because of the unnecessary of die and punches. However, achieving the goal is still a challenge for researchers. Bending of hard material causes springback, increase risk of cracking, and require large pressure. In this study, by mimicking from the traditional Origami that we should make crease line before folding, bending method by grooving at the bend-line is proposed to reduce the necessary force to constraint the blank and get a high limit of bending. Firstly, several shapes of groove are compared: half-circle, gauss distribution, half-haxegon and rectangle. Then based on the comparison, the optimization of the shape is investigated. Lastly, handling system is considered to find an effective way of grasping the blank.
Ring-Planet Mesh Stiffness Study With Different Boundary Conditions and Crack Locations
Authors: Xue Song , Howard Ian
Published: January 2016

The ring gear boundary conditions can have a great influence on the ring-planet mesh stiffness. Two different boundary conditions have been compared in this study using the finite element analysis (FEA) method, namely the full constraint condition and the pin-supported condition. Cracks can cause changes in the gear mesh stiffness and the effect of ring gear crack locations has been analysed under both boundary conditions. Multiple crack locations were chosen and especially in the pin-supported model, where the crack locations were between two pin supports. The same ring-planet mesh stiffness change between the healthy model and the cracked model was observed wherever the crack locations were in the full constraint model. However, different ring-planet mesh stiffness changes were observed when the cracks were implanted to different teeth in the pin-supported model. The highest value was observed when the crack was close to the pin support and the lowest value was observed when the crack was in the middle of two pin supports. These observed changes can provide additional information to help identify the locations of the ring gear cracks in the planetary gear when the mounting method makes use of pin-supports.
Proper Orthogonal Decomposition of Tapping Microcantilevers in Liquid Atomic Force Microscopy
Authors: Kim Il Kwang , Lee Soo Il
Published: January 2016

The modal decomposition of tapping mode atomic force microscopy microcantilevers in liquid environments was studied experimentally. Microcantilevers with different lengths and stiffnesses and two sample surfaces with different elastic moduli were used in the experiment. The response modes of the microcantilevers were extracted as proper orthogonal modes through proper orthogonal decomposition. Smooth orthogonal decomposition was used to estimate the resonance frequency directly. The effects of the tapping setpoint and the elastic modulus of the sample under test were examined in terms of their multi-mode responses with proper orthogonal modes, proper orthogonal values, smooth orthogonal modes and smooth orthogonal values. Regardless of the stiffness of the microcantilever under test, the first mode was dominant in tapping mode atomic force microscopy under normal operating conditions. However, at lower tapping setpoints, the flexible microcantilever showed modal distortion and noise near the tip when tapping on a hard sample. The stiff microcantilever had a higher mode effect on a soft sample at lower tapping setpoints. Modal decomposition for tapping mode atomic force microscopy can thus be used to estimate the characteristics of samples in liquid environments.
Enabling Reuse of Documentation in New Medical Device Development: A Systematic Architecting Approach
Authors: Jensen Troels Victor , Parslov Jakob Filippson , Mortensen Niels Henrik
Published: January 2016

Medical device companies are continuously challenged with the ability to prove compliance with increasingly complex regulatory frameworks. Operating under heavy regulatory requirements may therefore cause significant delays to the lead time of new medical devices and thus contribute significantly to time-to-market for even simple medical device development projects. In this paper we illustrate how medical device companies can reduce their research and development (R&D) efforts needed to prove compliance when developing new product families by means of platforming and modularization. The results presented in this paper are based on a two-year empirical case study of a European manufacturer of arterial blood gas (ABG) sampling devices. The core contribution of this paper is a systematic architecting approach that applies the concept of a delta-multi-domain matrix (ΔMDM) to support companies in justifying the reuse of verification and validation (V&V) test documentation packages across new product family designs. The paper introduces an approach to aligning product and documentation architectures by architecture mirroring, and emphasizes the need for having a one-to-one mapping between the product and V&V test view. This will allow for V&V-related documentation to follow the product platform, and thereby enable carry-over of test documentation packages from one product family to another. Hence, this approach can provide significant competitive advantages to companies as it increases R&D efficiency while reducing time-to-market for new medical device development.
Synthesizing Functional Mechanisms From a Link Soup
Authors: Tavousi Pouya , Kazerounian Kazem , Ilies Horea
Published: January 2016

The synthesis of functional molecular linkages is constrained by difficulties in fabricating nano-links of arbitrary shapes and sizes. However, the classical mechanism synthesis methods, which assume the ability to manufacture any designed links, do not provide a systematic synthesis process for molecular linkages.

We propose a new approach to build functional mechanisms with prescribed mobility by only using elements from a predefined link soup. First, we enumerate an exhaustive set of topologies, while employing divide-and-conquer algorithms to control the generation and elimination of redundant topologies. Then, we construct the linkage arrangements for each valid topology. Finally, we output a set of feasible geometries through a positional analysis step that minimizes the error associated with closure of the loops in the linkage while avoiding geometric interference. The proposed systematic approach outputs the ATLAS of candidate mechanisms, which can be further processed for downstream applications. The resulting synthesis procedure is the first of its kind that is capable of synthesizing functional linkages with prescribed mobility constructed from a soup of primitive entities.
Nonlinear Dynamics of an Automotive Differential Hypoid Gear Pair
Authors: Paouris Leonidas I. , Theodossiades Stephanos , Rahnejat Homer , Kidson Adam , Hunt Gregory , Barton William
Published: January 2016

The dynamics of an automotive differential hypoid gear pair is investigated. The gear pair model is a 4 degree-of-freedom torsional model, including the torsional deflections of the supporting shafts of the pinion and the gear. It also includes the dynamic transmission error of the mating teeth pairs. The variations in teeth contact stiffness/contact, principal radii of contact and static transmission error are determined during the meshing cycle, using the CALYX software. The equations of motion are solved using a numerical integration scheme. A preliminary parametric study is presented, enabling identification of different periodic responses as the vehicle cruising speed alters.
A Model to Predict Pocketing Power Losses in Spiral Bevel Gears
Authors: Erkilic E. , Talbot D. , Kahraman A.
Published: January 2016

A computational methodology is proposed for prediction of power losses due to pocketing (pumping or squeezing) of oil at the mesh interface of spiral bevel gears. The model employs an existing cutting simulation procedure to define surface geometries of the gears through face-milling and face-hobbing processes. A novel hypoidal discretization method is proposed to define pocket volumes between meshing gear teeth along circumferential and face width directions. An existing fluid mechanics formulation, utilizing principles of conservation of mass, momentum and energy, is used to compute the load-independent (spin) power losses due to pocketing of the medium in the gear mesh interface. A simulation of aerospace applications is presented to highlight the effects of lubrication conditions, on pocketing power losses.
Development of an Accurate Analysis Method for Predicting Axle Hypoid Gear System Deflection
Authors: Ma Qinglong , Xu Hai
Published: January 2016

Axle hypoid gear design needs axle system deformation data at mesh point under load to evaluate the contact pattern, contact pressure and bending stress of the gear pair. The system deformation data or gear deflection (GD), can be obtained through a standard test procedure defined several decades ago. The testing method has not been improved for data acquisition efficiency and reliability since then. Fundamentally it contains trade-offs that make contact pattern correlation difficult. It also cannot meet urgent axle development timing pressures and cost reduction requirements. Analysis methods have been developed in recent years to replace the testing method of GD calculation. However, published modeling methods have their own limitations, and still do not correlate well loaded contact pattern between testing and analysis. In this paper, existing approaches of GD calculation are first reviewed and compared. Then the development of a new method is outlined, which combines a general finite element software and a special gear bearing contact analysis tool in one process. The validation of the method is illustrated by comparing axle loaded contact pattern. Finally, two case studies are demonstrated. The first one shows the capability of the new method to investigate the compliance contribution of main axle components. The second one shows that during one gear rotation, GD experiences a significant variation which needs to be considered during gear design.
Development of a Cutting Force Model for Generating Gear Grinding
Authors: Hübner Florian , Klocke Fritz , Brecher Christian , Löpenhaus Christoph
Published: January 2016

One key component of powertrains is gears which are used in a continuously increasing quantity with improving quality. A productive process for finishing gears is the generating gear grinding process. The process is used mainly for large-batch production of small or mid-size gears after case hardening, especially in the automotive sector.

Currently, the knowledge regarding the generating grinding process is limited and research is based mostly on empirical studies. The reasons for this are complex contacting conditions as well as the undetermined interactions between various process parameters.

This paper focusses on current questions about generating gear grinding such as new approaches for a simulation based process design in consideration of cutting forces as well as the changing contact conditions.
Predictive Modeling Techniques to Forecast Energy Demand in the United States: A Focus on Economic and Demographic Factors
Authors: Deka Angshuman , Hamta Nima , Esmaeilian Behzad , Behdad Sara
Published: January 2016

Effective energy planning and governmental decision making policies heavily rely on accurate forecast of energy demand. This paper discusses and compares five different forecasting techniques to model energy demand in the United States using economic and demographic factors. Two Artificial Neural Network (ANN) models, two regression analysis models and one autoregressive integrated moving average (ARIMA) model are developed based on historical data from 1950–2013. While ANN model 1 and regression model 1 use Gross Domestic Product (GDP), Gross National Product (GNP) and per capita personal income as independent input factors, ANN model 2 and regression model 2 employ GDP, GNP and population (POP) as the predictive factors. The forecasted values resulted from these models are compared with the forecast made by the U.S. Energy Information Administration (EIA) for the period of 2014–2019. The forecasted results of ANN models and regression model 1 are close to those of the U.S. EIA, however the results of regression model 2 and ARIMA model are significantly different from the forecast made by the U.S. EIA. Finally, a comparison of the forecasted values resulted from three efficient models showed the energy demand would vary between 95.51 and 100.08 quadrillion British thermal unit for the period of 2014–2019.
Design Methodologies for Soft-Material Robots Through Additive Manufacturing, From Prototyping to Locomotion
Authors: Cohen Eliad , Vikas Vishesh , Trimmer Barry , McCarthy Stephen
Published: January 2016

Soft material robots have gained interest in recent years due to the mechanical potential of non-rigid materials and technological development in the additive manufacturing (3D printing) techniques. The incorporation of soft materials provides robots with potential for locomotion in unstructured environments due to the conformability and deformability properties of the structure. Current additive manufacturing techniques allow multimaterial printing which can be utilized to build soft bodied robots with rigid-material inclusions/features in a single process, single batch (low manufacturing volumes) thus saving on both design prototype time and need for complex tools to allow multimaterial manufacturing. However, design and manufacturing of such deformable robots needs to be analyzed and formalized using state of the art tools.

This work conceptualizes methodology for motor-tendon actuated soft-bodied robots capable of locomotion. The methodology relies on additive manufacturing as both a prototyping tool and a primary manufacturing tool and is categorized into body design & development, actuation and control design. This methodology is applied to design a soft caterpillar-like biomimetic robot with soft deformable body, motor-tendon actuators which utilizes finite contact points to effect locomotion. The versatility of additive manufacturing is evident in the complex designs that are possible when implementing unique actuation techniques contained in a soft body robot (Modulus discrepancy); For the given motor-tendon actuation, the hard tendons are embedded inside the soft material body which acts as both a structure and an actuator. Furthermore, the modular design of soft/hard component coupling is only possible due to this manufacturing technique and often eliminates the need for joining and fasteners. The multi-materials are also used effectively to manipulate friction by utilizing soft/hard material frictional interaction disparity.
A Multi-Robot Testbed for Adaptive Sampling Experimentation via Radio Frequency Fields
Authors: Acain Jose , Kitts Christopher , Adamek Thomas , Ebadi Kamak , Rasay Mike
Published: January 2016

Adaptive navigation is the process by which a vehicle determines where to go based on information received while moving through the field of interest. Adaptive sampling is a specific form of this in which that information is environmental data sampled by the robot. This may be beneficial in order to save time/energy compared to a conventional navigation strategy in which the entire field is traversed. Our work in this area focuses on multi-robot gradient-based techniques for the adaptive sampling of a scalar field. To date, we have experimentally demonstrated multi-robot gradient ascent/descent as well as contour following using automated marine surface vessels. In simulation we have verified controllers for ridge descent / valley ascent as well as saddle point detection and loitering. To support rapid development of our controllers, we have developed a new testbed using wireless transmitters to establish a simple, large-scale, customizable scalar field based on the strength of the radio frequency field. A cluster of six land rovers equipped with radio signal strength sensors is then used to process sampled data, to make adaptive decisions on how to move, and to execute those moves. In this paper, we describe the technical design of the testbed, present initial experimental results, and describe our ongoing research and development work in the area of adaptive sampling and multi-robot control.
Application of Model Predictive Control to Position and Height Limitation of a Quadrotor Unmanned Aerial Vehicle
Authors: Dong Yiqun , Liu Zhixiang , Yu Bin , Zhang Youmin
Published: January 2016

This paper discusses a position and height limitation control for a quadrotor UAV (Unmanned Aerial Vehicle) using Model Predictive Control (MPC) approach. Nonlinear dynamics of the quadrotor is discussed first, and decoupled linearized dynamics is obtained. For the implementation of MPC, extended state vector of vehicle is generated, and augmented linear dynamics is constructed. The MPC in this paper utilizes a set of Laguerre function as basis to approximate the future movement of modeled vehicle. Position/height constraints and vehicle actuator characteristics enter the dynamics as linearized inequalities, which could be solved on-line via a recursive optimization approach. While validations based on experimental tests will be conducted in future, currently simulations have been completed. Based on the simulation results, when state of the vehicle is laid within the permissible bound, it retains the same dynamics of original vehicle. However, if predicted response exceeds the limits, however, MPC will take effect and restrict associate vehicle states. The discussed MPC framework in this paper is considered to be applicable.
Design of a Durable Air-Muscle With Integrated Sensor for Soft Robotics
Authors: Miron Geneviève , Plante Jean-Sébastien
Published: January 2016

Soft robotics integrates compliant actuators and sensors that expand design possibilities beyond classic robotics based on rigid modular components. In particular, deformable elastomer-based actuators used in soft robots, such as air-muscles, offer the possibility of having large numbers of embedded degrees of freedom. However, air-muscles fatigue life and strain capability call for a tradeoff, limiting their practical use in demanding applications such as physical rehabilitation, medical robotics, and mobile robots. This paper presents the design of a durable high-strain air-muscle composed of a silicone tube and an axially elastic sleeve (radially rigid), which integrates a flexible Dielectric Elastomer (DE) position sensor. The uniformity of the sleeve, by opposition to usual braids, makes for a reinforcement without local stresses that cause membrane failure. Designed based on fatigue failure principles, this air-muscle withstands 145 000 cycles at 50 % elongation, which demonstrates its potential as a durable high-strain actuator. Performance maps of the air-muscle confirm good linearity between force, pressure and strain and demonstrate bi-directional force capability. Furthermore, the integration of a DE sensor allows for accurate position control of the air-muscle (0.17 mm), making the air-muscle/sensor unit a relevant building block for complex soft robotics systems. The all-polymer high-strain actuator/sensor unit proves to be accurate and durable as well as cost-effective, thus making it ideal for soft robotics applications requiring large numbers of actuators and integrated sensing.
Fatigue Life Analysis of an Automotive Tensioner Through Strain-Life Approach
Authors: Talimi Maryam , Zu Jean W.
Published: January 2016

In this paper, fatigue life assessment of a tensioner is studied through dynamic load analysis, stress analysis, and stress-life fatigue analysis approach. Tensioner is a critical part of an automotive front end accessory drive system, providing pre-tension to the belt. The front end accessory drive systems are responsible for transmitting power from the crankshaft to the accessory components. Due to the engine pulsation, components of the accessory drive including the tensioner are subjected to dynamic loads leading to fatigue failure. The fatigue life assessment of a mechanical component highly depends on loading, geometry, and material properties. In addition, the dynamic behavior of the front end accessory drive is complicated due to coupling between several modes of vibrations in belt, pulleys, and the tensioner arm. Duo to the complexity of the parameters involved and complicated dynamics, the fatigue life analysis of FEAD components is a challenging task. This paper includes three main parts, namely stress analysis, fatigue properties prediction, and life estimation. The dynamic analysis of a generic front end accessory drive system is performed in order to obtain effective loads on the tensioner. Stress state for the tensioner in case of different applied loading conditions is performed via a series of Finite Element (FE) analyses, and the critical region of the part is determined. Finally, fatigue life is estimated through strain-life approach. Modest work has been found in this area providing a comprehensive solution to the fatigue life investigation of power train components. The present study offers a comprehensive modeling approach which predicts the automative tensioner lifetime. The lifetime of any FEAD system components can be determined using the developed fatigue life prediction approach.
Physical Properties of LLDPE and PP Filled With Wood Flours
Authors: Bas Gamze Sultan , Sancaktar Erol , Karadurmus Erdal
Published: January 2016

In this study, composites of polypropylene (PP), as well as linear low density polyethylene (LLDPE) thermoplastics filled with wood flour have been investigated to study the effect of size and amount of wood flour on their mechanical, thermal and aging properties. PP and LLDPE were mixed with five different types of wood flour, i.e., cedar, maple, oak, poplar, and select pine, by adding different percentages of wood flour at 30, 40 and 50 weight percentages. Mixing was done using a mini compounder at 180–210°C and dog-bone shape samples were produced by using a mini-injection molding machine. Two different sizes of wood flour labeled as thin (425–500 μm) and thick (600–710 μm) were compared for PP-wood and LLDPE-wood composites. Mechanical properties of blends were investigated by tensile testing and thermal behaviors of blends were characterized by using DSC analyses. Poplar and maple show better tensile results among other wood types with 543.7 MPa and 600.5 MPa Young’s modulus and 21.05 MPa and 24.53 MPa tensile strength for LLDPE when comparing thick and thin wood flour blends, respectively. In the case of PP; poplar and select pine gave higher Young’s modulus and tensile strength results. Samples were also aged in acid and water solution for 3 days, and their weight and dimensional changes were recorded and compared with neat polymer samples to show physical stability.
Kinematic Analysis of 3D Printing Mechanisms
Authors: Talpasanu Ilie , Chomyszak Stephen
Published: January 2016

The paper presents a novel technique for the kinematic analysis of a geared mechanism manufactured through 3D printing technology. In the syllabus of the undergraduate 3D Printing course, one of the student projects is to manufacture a spur Norton type gear box which includes a planetary mechanism for engaging its three planets, thus three output velocities for the gear box are obtained. The connected elements (carriers, gears, planets) are fabricated without any involvement of assembly operation. At the prototype stage, a CAD model of the mechanism is created and a search for abilities and limitations of the mechanism are required. The analysis of abilities of motion includes determination of mechanism mobility (DOF). A step by step simple technique is presented for determination of the rank for the matrix of coefficients from the kinematic equations. Thus, the DOF is the difference between the number columns and the rank previously determined. The steps required in the analysis are: numbering of links and joints, graph attached to mechanism, matrix of incidence cycles-nodes in graph, and determination of its rank by using Mathematica commands. For the set of base cycles are automatically generated independent scalar equations. The matrix, denoted velocity matroidal, has the coefficients for the mechanism’s unknown absolute angular velocities-determined based on an analogy to a system of parallel forces from static equilibrium, angular velocities being considered analog to the “forces“. The relations between the input-output links’ absolute angular velocities are determined. The coefficients in the kinematic equations for velocities are written as function of gear ratios. The number of gear teeth can be selected also for the desired input-output speed ratios.
Energy Harvesting Using the Rattleback: Theoretical Analysis and Simulations of Spin Resonance
Authors: Nanda Aditya , Karami M. Amin , Singla Puneet
Published: January 2016

This paper investigates the spin resonance of a rattleback subjected to base oscillations. The phenomenon of Spin resonance can transduce vibrations to rotations. The rattleback is an ellipsoidal top with a preferred direction of spin. If rotated anti to it, longitudinal vibrations are set up and spin direction is reversed.

Simulations and results are presented which show that the rattleback has a mono-peak spin resonance with respect to base vibrations. Two frequencies that appear in the response are identified — the Coupled and Uncoupled frequencies. Spin resonance, it is deduced, occurs when the base frequency is twice the coupled frequency of the rattleback. A linearized model is developed and a closed form expression for the Resonant frequency in terms of the inertia parameters of the rattleback is derived.

Novel ideas for applications in Energy harvesting and Vibration sensing that utilize the phenomenon of spin resonance are also included.
Emission wavelength control in InAs(Sb) quantum dashes-in-a-well structures
Authors: Addamane Sadhvikas , Mansoori Ahmad , Dawson Noel , Hains Christopher , Dawson Ralph , Balakrishnan Ganesh
Published: January 2016

The authors have explored emission wavelength control in InAs quantum dashes (QDashes) grown on InP substrates by manipulation of the InAs thickness and by incorporating Sb into the QDashes. It is found that by increasing the InAs coverage, the photoluminescence (PL) emission wavelength can be extended up to 2.15 μm. The authors have also demonstrated that by introducing Sb into the InAs QDashes, the emission wavelength can be further increased to 2.25 μm. They have characterized surface morphology using atomic force microscopy to study the effect of both the above-mentioned techniques on the shape and size of InAs QDashes. Also, temperature-dependent PL studies are carried out to understand the carrier dynamics in InAs QDashes emitting at extended wavelengths. Based on these results, it is concluded that the incorporation of Sb is a better technique compared to increasing InAs coverage to extend the emission wavelength of InAs QDashes.
Modeling of aerodynamic interaction between vocal folds and vocal tract during production of a vowel–voiceless plosive–vowel sequence
Authors: Delebecque Louis , Pelorson Xavier , Beautemps Denis
Published: January 2016

The context of this study is the physical modeling of speech production. The objective is, by using a mechanical replica of the vocal tract, to test quantitatively an aerodynamic model of the interaction between the vocal folds and the vocal tract during the production of a vowel–voiceless plosive–vowel sequence. The first step is to realize acoustic and aerodynamic measurements on a speaker during the production of an /apa/ sequence. The aperture and width of the lips are also derived from a high-speed video recording of the subject's face. Theoretical models to describe the flow through the lips and the effect of an expansion of the supraglottal cavity are proposed and validated by comparison with measurements made using a self-oscillating replica of the phonatory system. Finally, using these models, numerical simulations of an /apa/ sequence are performed using the measured lip parameters as the only time-varying input parameters. The results of these simulations suggest that the realization of an occlusion of the vocal tract produces a passive increase in glottal area associated with a voice offset and that the expansion of the supraglottal cavity is responsible for the extension of the phonation up to 40 ms after closure of the lips.
Effects of an 8-Week Structured Physical Activity Program on Psychosocial Behaviors of Children With Intellectual Disabilities
Authors: Choi Peggy Hiu Nam , Cheung Siu Yin
Published: January 2016

The study aimed to investigate the impact of an 8-wk structured physical activity program on selected psychosocial behaviors of children with intellectual disabilities (ID) and to estimate whether generalization occurred. Thirty children (22 boys, 8 girls) with mild ID took part in the study. The ANCOVA results showed a significant difference between the training group and the control group in emotional self-control mean scores, F(1, 25) = 7.61, p = .011, with the posttest mean score of the training group being better than that of the control group. The correlation analysis showed a medium, positive correlation between the gain scores of emotional self-control in the training context and classroom context of the training group (r = .41, n = 16, p = .12). Hence, generalization appeared to have occurred.
Hypoxia micromanages glioma
Authors: Ferrarelli Leslie K.
Published: January 2016

Hypoxia alters microRNA biogenesis in glioma cells to promote adaptation in the tumor microenvironment.
Papers of note in
Science
Authors: Gough Nancy R.
Published: January 2016

This week’s articles feature insights into how a micropeptide enhances muscle performance and how an energy-sensing kinase triggers mitochondrial fragmentation.