bluuebunny/crossref_metadata_2025 huggingface dataset:
The Layout Measurement Points Prediction and Flatness Calculation for the Antenna Plate After Welding Assembly Based on the RBF Neural Network Model
Authors: Pan Minghui , Tang Wencheng , Xing Yan , Ni Jun
Published: December 2016

Due to the effect of the antenna plate flatness on the antenna performances, the flatness is one of the key performance indicators for the planar antenna. Before calculating the antenna plate flatness, the support assembly tools are built, and then measuring experiment for height coordinate values is carrying out on the assembly platform. This paper presents a predictive method that is the Radial Basis Function (RBF) neural network method to obtain the height coordinate values based on fewer measurement points on the antenna plate after welding assembly, and the antenna plate flatness is calculated by fitting least square plane using measuring point coordinate value through the least square method (LSM). Simultaneously, before or after welding assembly, comparing with the calculated flatness value, it is shown that the calculated flatness value by the predicted height coordinate values basically agrees well with the initial calculated flatness value. These results reveal that the RBF neural network prediction is adopted to be very correct and valid, which will reduce the measurement cost and improve measurement efficiency in future.
Decision Making in Course Design
Authors: Herrmann Jeffrey W.
Published: December 2016

Decision making is an important feature of design. Although engineering design refers to the design of products and technical systems, design activities occur in many other professions, including education. As education moves from teaching to learning, engineering faculty are becoming course designers who make many decisions when designing a course. Although many course design processes have been described, previous work has not considered course design as an interrelated set of decisions. To plan a course, a designer must make decisions. The course designer must select following elements: the purposes of the course, the content, its sequence, the instructional resources, and the instructional processes. These decisions occur at different “levels”: some determine “small” parts of the course (such as the media for one activity), and some determine “large” parts of the course (such as the sequence of topics). This paper, an initial step towards decision-based instructional design, describes the decisions that need to be made to design a typical academic course, the different ways in which these decisions are logically related to each other, and the objectives relevant to these decisions. These descriptions, which focus on the logical relationship between the decisions, do not form a complete course design process. Designing better courses requires selecting better alternatives for the many decisions that must be made. The objectives used to guide these decisions are thus a critical part of course design. These objectives include meeting a specific need in a satisfactory way, using an established rule or heuristic, maximizing effectiveness, optimizing a metric that is correlated with effectiveness, reducing the costs and resources required to develop and offer the course, and maximizing cost-effectiveness. This paper presents a simple model that describes the relationships between the course design, the instructor’s actions, the students’ actions, the initial and recurring costs of a course, the course effectiveness, and the utility (value) of the course. Based on this model, one could formulate a comprehensive instructional design problem: select the course design that maximizes the expected utility (value). Although there may be other factors that should be included in this model and we may currently be far away from formulating and solving this comprehensive instructional design problem, it can serve as a goal to motivate future research. This paper presents a new perspective for understanding course design, and elaborating this view can increase our understanding of engineering education and help those who are designing engineering courses. Describing these steps as decisions is an important step towards helping instructors make better decisions, which can yield more effective course designs and enhance student learning. This paper adds to our knowledge of engineering education by identifying the types of decisions involved and the objectives that can be used to make those decisions.
Bi-BCM: A Closed-Form Solution for Fixed-Guided Beams in Compliant Mechanisms
Authors: Ma Fulei , Chen Guimin
Published: December 2016

A fixed-guided beam is one of most commonly used flexible segments in compliant mechanisms such as bistable mechanisms, compliant parallelogram mechanisms, compound compliant parallelogram mechanisms and thermomechanical in-plane microactuators. In this paper, we split a fixed-guided beam into two elements, formulate each element using the Beam Constraint Model (BCM) equations, and then assemble the two elements’ equations to obtain the final solution for the load-deflection relations. Interestingly, the resulting load-deflection solution (referred to as Bi-BCM) is closed-form, in which the tip loads are expressed as functions of the tip deflections. The maximum allowable axial force of Bi-BCM is the quadruple of that of the BCM. Bi-BCM also extends the capability of the BCM for predicting the second buckling mode of fixed-guided beams. Besides, the boundary line between the first and the second buckling modes of fixed-guided beams can be easily obtained using a closed-form equation. Bi-BCM can be immediately used for quick design calculations of compliant mechanisms utilizing fixed-guided beams as their flexible segments (generally no iteration is required). Different examples are analyzed to illustrate the usage of Bi-BCM, and the results show the effectiveness of the closed-form solution.
Airflow Interaction Interface: Playful 3-D CAD and Gaming
Authors: Wendrich Robert E.
Published: December 2016

This paper describes the vision and development of a tangible user interface (TUI) that allows ‘glassblowing-like’ interaction (IA) with a computer. The premise is that human fidelity in exerting pressure and airflow (i.e. breathing, blowing) could stimulate intuition, creative processing, and affords unconventional human-computer interaction (UHCI). The ultimate goal is to find out how the potential of the human body can be used to design, develop and analyze new spatial interaction methods that surpass performance or application possibilities of currently available techniques. Multi-modal interactions are essential to computational processing whereby the human and machine are interconnected and coupled to enhance skills (analogue and digital), support rich performance, facilitate learning and foster knowledge in design and engineering processing. This paper describes the key concept of the TUI, the graphical user interface (GUI) and the data visualizer system. We illustrate the concept with a prototype system — the Air-Flow-Interaction-Interface (AFIF), testing and experimentation — to identify underlying research issues.
A Taxonomy for Representing Prismatic Cellular Materials
Authors: Fazelpour Mohammad , Summers Joshua D. , Blouin Vincent Y.
Published: December 2016

A taxonomy is developed to describe prismatic cellular materials (PCM) explicitly to allow for unambiguous discussion of cellular topology. The taxonomy represents a PCM through describing (1) the unit cell (UC) and (2) the tiling or unit cell arrangements. The UC is described through three characteristics: boundary, interior, and connections of the unit cell with its adjacent structural members. Each of these are further refined into sub-divisions. The taxonomy is evaluated through three metrics: completeness, perceptual orthogonality, and depth. Using this descriptive taxonomy, researchers can more uniformly describe the development efforts that they are pursuing.
Developing Design Guidelines for Meso-Scaled Periodic Cellular Material Structures Under Shear Loading
Authors: Fazelpour Mohammad , Shankar Prabhu , Summers Joshua D.
Published: December 2016

Much research has been conducted on effective elastic properties of meso-scaled periodic cellular material (MPCM) structures; however, limited research is found in the literature for design guidelines to develop a unit cell (UC) topology and shape for multiple loading conditions. The current methods to design topology of unit cells has experienced limitations including numerical modeling challenges and trial-and-error associated with topology optimization and intuitive methods, respectively. To address this limitation this paper aims to develop guidelines for redesign of unit cell topology and shape under in-plane shear loading. The guidelines are intended to use design knowledge for helping engineers by providing recommendations at any stage of the design process. In this paper, the guidelines are developed by changing topology characteristics to achieve a desired effective property of a MPCM structure. The effect of individual members such as side connection and transverse connection of MPCM structure when subjected to in-plane shear loading are investigated through conducting a set of numerical simulation on UCs with similar topology and shape characteristics. Based on the simulation results, the unit cell design guidelines are developed to provide recommendations to engineers on improving shear flexure of MPCM during the design process.
An Approach to Assess Value of Component Commonality by Integrating Product Design and Supply Chain Decisions
Authors: Takai Shun , Sengupta Sankar
Published: December 2016

Delayed differentiation enables firms to cost effectively offer a large variation of the same product by using common components until the products need to be differentiated for regional requirements. Using the same components in different product models (component commonality) is the key to enabling delayed differentiation. The objective of this paper is to propose an approach to evaluate the value of component commonality by integrating product design decisions and supply chain decisions. We propose an approach to assess the value of component commonality by simultaneously optimizing product design (i.e., component commonality) and supply chain decisions including supplier selection (replenishment lead time) and inventory policy. The proposed approach is illustrated in motor commonality decisions for electric bicycles. The optimum component commonality and supply chain decisions are investigated under various conditions including different demand variabilities, component costs, inventory tracking costs, and inventory ordering costs.
A Study on the Dynamics of Spatial Mechanisms With Frictional Spherical Clearance Joints
Authors: Marques Filipe , Isaac Fernando , Dourado Nuno , Souto António Pedro , Flores Paulo , Lankarani Hamid M.
Published: December 2016

An investigation on the dynamic modeling and analysis of spatial mechanisms with spherical clearance joints including friction is presented. For this purpose, the ball and the socket which compose a spherical joint are modeled as two individual colliding components. The normal contact-impact forces that develop at the spherical clearance joint are determined by using a continuous force model. A continuous analysis approach is used here with a Hertzian based contact force model, which includes a dissipative term representing the energy dissipation during the contact process. The pseudo-penetration that occurs between the potential contact points of the ball and the socket surface, as well as the indentation rate play a crucial role in the evaluation of the normal contact forces. In addition, several different friction force models based on the Coulomb’s law are revisited in this work. The friction models utilized here can accommodate the various friction regimens and phenomena that take place at the contact interface between the ball and the socket. Both the normal and tangential contact forces are evaluated and included into the systems’ dynamics equation of motion, developed under the framework of multibody systems formulations. A spatial four bar mechanism, which includes a spherical joint with clearance, is used as an application example to examine and quantify the effects of various friction force models, clearance sizes, and the friction coefficients.
Transmission Error due to Resonance in Synchronous Belt Drive With Eccentric Pulley
Authors: Kagotani Masanori , Ueda Hiroyuki
Published: December 2016

In synchronous belt drives, it is generally difficult to eliminate pulley eccentricity, because the pulley teeth and shaft hole are produced separately. This eccentricity affects the accuracy of rotation transmission, so that the belt tension changes during a single rotation of the pulley. This in turn affects the occurrence of resonance in the spans. In the present study, the transmission error in a synchronous belt drive with an eccentric pulley in the absence of a transmitted load was experimentally investigated for the case in which the spans undergo first-mode transverse vibration due to resonance. The transmission error was found to have a component with a period equal to the displacement of the span, in addition to a component with a period of half the displacement of the span. During a single rotation of the pulley, the magnitude of the transmission error increased, and its frequency decreased, with decreasing belt tension. The transmission error exhibited the large value when two frequency conditions were satisfied: one was that the meshing frequency was within the range of span frequency variations due to the eccentricity, and the other was that the minimum frequency of the span was close to an integer multiple of the rotation frequency of the pulley. Even if both of these conditions occurred, if the range of span frequency variations due to the eccentricity was larger than 13 Hz, the transmission error could be eliminated by adjusting the belt tension so that the average frequency of the span corresponded to the meshing frequency.
Vibration-Based Damage Accumulation Modeling
Authors: Belegundu Ashok D. , Nayak Sumanta K. , Loverich Jacob , Grissom Michael D.
Published: December 2016

A simple methodology is presented which takes input data from wireless accelerometers used in continuous monitoring of large numbers of machines such as pumps, motors, gearboxes, and fans, and outputs a damage accumulation metric which can be used for early warning indication for a broad range of faults. Based on the output, maintenance visits can be made to inspect the machines. Emphasis is on ease of use and broad applicability. It is assumed that the accelerometer data reflects damage occurrence. The approach here is based on time series vibration data analysis that estimates the rate at which damage is accumulated at a given location. This indicator accounts for time-varying symptoms in machines which are often overlooked by traditional vibration diagnostic frequency analysis. As fatigue analysis is the foundation for the damage metric, contribution of repeated load reversal cycles to component damage and the nonlinearity in the relationship between damage and vibration amplitude, are incorporated. A MATLAB code has been developed and validated from simple examples in the literature. The methodology is then applied to a finite element model of a defective shaft-bearing assembly, and in a high pressure pumping field application.
Design and Analysis of a Bat-Like Active Morphing Wing Mechanism
Authors: Ma Nan , Zhou Xiaodong , He Guangping , Yu Jingjun
Published: December 2016

The flying style of bats has much difference with the birds and insects, which adopt the backward folding movement of the wing when up flapping. The wingspan is changed during the up and down flapping, which makes the effective flapping area difference and the net lift increase. Firstly, basing on the research of bats’ flapping style, the mechanism of active morphing wing is proposed, then the dimensional synthesis is carried out basing on the movement trajectory of bats’ wing, after that, the kinematic model is build and analyzed, and the analysis result is compared with the ADAMS software. The flapping and morphing of the wing is actuated by a single motor, which can increase the power coefficient of the system and realize the coupled flapping and folding motion of the wing at the same time. The folding and stretching of the wing is actuated by a cam installed on the axis of crank, then the space flapping trajectory of the wing can be planed by changing the cam contour and the installation phase, this mechanism provide a way to design the foldable flapping wing aerial vehicles (FWAV).
Deployment Simulation of Miura-Origami Membrane Structures
Authors: Cai Jianguo , Ren Zheng , Ding Yifan , Feng Jian , Deng Xiaowei , Zhou Wu , Xu Yixiang
Published: December 2016

In recent years, with the development of the space industry, thin film reflector structures have the feature of lightweight, high compact ratio, easy to fold and unfold and so on. Its form has received wide attention from researchers and a broad application prospect. In this paper, the nonlinear finite element software ABAQUS was used to carry out the numerical simulation of the deployment of membrane structures based on Miura-ori, by taking advantage of the variable Poisson’s ratio model to revise the stress distribution of membrane elements. Then the uniaxial tension tests were carried out to study the material properties of the polyimide film. The effective elastic modulus was used to simulate the crease of the membrane. The deployment of a membrane structure based on Miura origami pattern was studied. Moreover, effects of some parameters, such as the number of loading nodes and the loading rate on the numerical results were discussed.
Eigenvector Rotation as an Estimation of Architectural Change
Authors: Dong Andy , Sarkar Somwrita , Moullec Marie-Lise , Jankovic Marija
Published: December 2016

Many important technical innovations occur through changes to existing system architectures. To manage the balance between performance gains by the innovation and the risk of change, companies estimate the degree of architectural change an innovation option could cause due to change propagation throughout the entire system. To do so, they must evaluate the innovation options for their integration cost given the present system architecture. This article presents a new algorithm and metrics based upon eigenvector rotations of the architectural connectivity matrix to assess the sensitivity of a system architecture to introduced innovations, modelled as perturbations on the system. The article presents studies of the impact of changes on synthetic system architectures to validate the method. The results show that there is no single architecture that is the most amenable to introduced innovation. Properties such as the density of existing connections and the number of changes that modify intra- or inter-module connections can introduce global effects that are not known in advance. Hierarchical modular system architectures tend to be relatively stable to introduced innovations and distributed changes to any architecture tends to cause the largest eigenvector rotations.
A Cluster Analysis Study of Opportune Adoption of Electric Drive Vehicles for Better Greenhouse Gas Reduction
Authors: Hamza Karim , Laberteaux Kenneth P.
Published: December 2016

Adoption of electric drive vehicles (EDVs) presents an opportunity for reduction of greenhouse gas (GHG) emissions. From an individual vehicle standpoint however, the GHG reduction can vary significantly depending on the type of driving that the vehicle is used for. This is primarily due to conventional vehicles (CVs) having poor energy efficiency in stop-and-go city-like driving compared to their performance in steady highway-like driving. This study attempts to examine the magnitude of the differential in GHG reduction benefit for real driving behaviors obtained from California Household Travel Survey (CHTS-2013). Recorded vehicles speed traces are analyzed via a fuel economy simulator then a hybrid support vector clustering (SVC) technique is applied to form groups of vehicle samples with similar driving behaviors. Unlike many clustering techniques, SVC does not impose a pre-dictated number of clusters, but has a number of parameters that must be tuned in order to obtain meaningful results. Tuning of the parameters is performed via a multi-objective evolutionary algorithm (SPEA2) after formulating the cluster tuning as a two-objective problem that seeks to maximize: i) differential benefit in GHG reduction, and ii) fraction of the population that groups of vehicles represent. Results show that replacing a CV with its equivalent hybrid (HEV) can reduce GHG emissions per mile of driving by 2 to 2.5 times more for a group of vehicles (best opportune for an EDV) compared to the less opportune group.
Controlling Chaos of Planar Closed Chain Underactuated Mechanism With the Edge of Chaos
Authors: Xie Jin , Ren Bichun , Liu Zhaohui , Chen Yong
Published: December 2016

Under some circumstances, a planar closed chain five-bar underactuated mechanism exhibits chaotic motion. The edge of chaos is the transitory region between deterministic and chaotic motion. A new idea to control chaos by changing the parameters of the dynamical system at the edge of chaos is proposed in this paper. Permutation entropy is employed to detect the edge of chaos, and its normalizing equation is modified for making it more sensitive to the irregularity of the time series. Instead of the dynamical edge of chaos, the static edge of chaos is utilized to make the plan of controlling chaos. The study is conducted experimentally. The results show that the method proposed in this paper can control the chaos arising from the underactuated mechanism successfully.
Topological and Kinematic Performance Analysis of a Class of 5-SPS Parallel Mechanisms With Line Moving Platform
Authors: Shen Huiping , Huang Jun
Published: December 2016

This paper is to design a class of manipulators capable of producing five DOF (degree-of-freedom) output motion for controlling the position and orientation of a line. Four novel 5-SPS parallel mechanisms with LMP (Line Moving Platform) are proposed according to the structure coupling-reducing principle proposed by authors on the basis of an existing 5-SPS parallel mechanism with LMP. Three key topology characteristics, such as structure coupling degree, output position and orientation characteristics, input-output kinematic decoupling, and the position workspace characteristics, as the fourth characteristic, of these five 5-SPS parallel mechanisms with LMP are calculated and compared respectively. It shows that the use of concentric spherical joints on the moving platform can reduce coupling degree of mechanisms and simplify the forward displacement and the workspace analysis. The mechanisms with triple-spherical-joint structure have input-output motion decoupling. Therefore, each of the 5-SPS parallel mechanisms with LMP has its own advantages and applications. This paper provides a foundation for engineering design, optimal selection and potential application of the five 5-SPS parallel mechanisms with LMP.
A Comparison of Several SDOF Models of Gear Dynamics
Authors: Yu Wennian , Mechefske Chris K. , Timusk Markus
Published: December 2016

It is commonly believed that a complete understanding of gear dynamics is essential for the design of gear transmission systems capable of running at low noise and vibration levels with prolonged service life. Several single degree of freedom (SDOF) models of gear dynamics with clearance nonlinearity are generalized based on previous research, while a constant damping ratio is assumed and the friction is neglected. These models include the effects of time-varying mesh stiffness, gear manufacturing errors, profile modifications and backlash. Comparisons of the steady responses predicted by these SDOF models are intensively studied and the relationships between these models are discussed. Even though, different types of mesh stiffness and different treatments of the gear error functions in the analysis are used in these models, the steady-state responses predicted by these models are generally consistent with each other and agree well with experimental results. However, some discrepancies and relationships do exist among these models. The advantages and disadvantages of each model are highlighted.
ANCF Tetrahedral Solid Element Using Shape Functions Based on Cartesian Coordinates
Authors: Mohamed Abdel-Nasser A.
Published: December 2016

This paper introduces a new solid, four-node, fully parameterized, tetrahedron element. The tetrahedron element is based on the absolute nodal coordinate formulations in which the absolute position vector and three slope vectors are considered nodal coordinates. The linear transformation of the shape functions from the tetrahedron coordinates to Cartesian coordinates leads to very stiff elements. On the other hand, the nonlinear transformation from tetrahedron coordinates to Cartesian coordinates is very complicated. Therefore, the use of the barycentric coordinates was bypassed and the Cartesian coordinates were used to define the cubic polynomial shape functions. The volumetric integration of the mass matrix, elastic force and gravity force was performed using the trapezoidal rule. It is easily shown that the resulting element satisfies the conformity conditions. The numerical results show that the proposed element does not suffer from Poisson locking. Furthermore, the numerical results show that comparing to fully parametrized brick elements, the proposed element experiences poor convergency and excessive computational time.
Time-Dependent Reliability Analysis Using a New Multivariate Stochastic Load Model
Authors: Hu Zhen , Mahadevan Sankaran
Published: December 2016

A common strategy for the modeling of stochastic loads in time-dependent reliability analysis is to describe the loads as independent Gaussian stochastic processes. This assumption does not hold for many engineering applications. This paper proposes a Vine-autoregressive-moving average (Vine-ARMA) load model for time-dependent reliability analysis, in problems with a vector of correlated non-Gaussian stochastic loads. The marginal stochastic processes are modeled as univariate ARMA models. The correlations between different univariate ARMA models are captured using the Vine-copula. The ARMA model maintains the correlation over time. The Vine-copula represents not only the correlation between different ARMA models, but also the tail dependence of different ARMA models. The developed Vine-ARMA model therefore can flexibly model a vector of high-dimensional correlated non-Gaussian stochastic processes with the consideration of tail dependence. Due to the complicated structure of the Vine-ARMA model, new challenges are introduced in time-dependent reliability analysis. In order to overcome these challenges, the Vine-ARMA model is integrated with a recently developed single-loop Kriging (SILK) surrogate modeling method. A hydrokinetic turbine blade subjected to a vector of correlated river flow loads is used to demonstrate the effectiveness of the proposed method.
Infrastructure Inspection Using an Unmanned Aerial System (UAS) With Metamodeling-Based Image Correction
Authors: Kuo Chen-Ming , Kuo Chung-Hsin , Lin Shu-Ping , Manuel Mark Christian E. , Lin Po Ting , Hsieh Yi-Chi , Lu Wei-Hao
Published: December 2016

Public infrastructures such as bridges are common civil structures for road and railway transport. In Poland, many of the steel truss bridges were constructed in the 1950s or earlier. The aging managements and damage assessments are required to ensure safe operations of these old bridges. The first step of damage assessment is usually done via visual inspection. The said inspection procedure can be expensive, laborious and dangerous as it is often performed by trained personnel. As a solution to this, we have developed and used a custom-designed, modular aerial robot equipped with a CCD camera for the collection of high-resolution images. The images were merged into one single, high-resolution facade map that will be the basis for subsequent evaluation by bridge inspectors. It was observed that the collected images had encountered irregularities which decreases the reliability of the facade map. We have conducted experiments to estimate the correction of image perspective in terms of attitude and position of unmanned aerial vehicle (UAV). A Kriging model was utilized to parametrically model the aforementioned nonlinear relationship. The image reliability is then evaluated based on the variance of the parametric model. The generated information is further used for high fidelity automated image correction and stitching.
Piezoelectric Compliant Mechanism Energy Harvesters Excited Under Large Base Accelerations
Authors: Ma Xiaokun , Trolier-McKinstry Susan , Rahn Christopher D.
Published: December 2016

A piezoelectric compliant mechanism (PCM) energy harvester is designed, modeled, and analyzed that consists of a polyvinylidene diflouoride, PVDF unimorph clamped at its base and attached to a compliant mechanism at its tip. The compliant hinge stiffness is carefully tuned to approach a low frequency first mode with an efficient (nearly quadratic) shape that provides a uniform strain distribution. A nonlinear model of the PCM energy harvester under large base excitation is derived to determine the maximum power that can be generated by the device. Simulation results show that the PCM bridge structure self-limits the displacement and maximum strain at large excitations compared with the proof mass cantilever, improving the device robustness. The PCM outperforms the cantilever in both average power and power-strain sensitivity at high accelerations due to the PCM axial stretching effect and its more uniform strain distribution.
Development of a Reference Part for the Evaluation of Economic and Ecological Impact of Future Process Chains in Mold Core Making
Authors: Kafara Markus , Westermann Hans-Henrik , Eisinger Eva , Steinhilper Rolf
Published: December 2016

Driven by the high importance of resource efficiency the importance of lightweight construction rises across all industries. Due to their high lightweight construction potential, carbon fiber reinforced plastics (CFRP) are increasingly applied.

But CFRP manufacturing often is an expensive small-scale production where it is necessary to use removable mold cores to manufacture hollow parts. To improve the complex process of mold core making future process chains including additive manufacturing (i.e. 3D-printing) can be used.

This paper provides a proposal for a hollow CFRP reference part based on facts taken directly from the field of application. The reference part will allow the evaluation of economic and ecological impact of process chains in mold core making for the CFRP production. Therefore, representative parts from different industry sectors were selected and analytically examined regarding their geometrical features. Based on a scientific recomposition of these features the reference part was developed.
Design of a 2-DOF Flexure Platform for Unbalance Measurement
Authors: Zhao Hongzhe , Zhang Shuqing , Ren Siyuan , Zhou Xiaodong
Published: December 2016

The traditional measurement platform for unbalance moment exploits the knife-edge as the support module but its performance rapidly deteriorates as the edge is worn down. In this paper, the flexure mechanism is utilized to overcome this drawback. The generalized cross-spring pivot is designed to achieve the approximate constant rotational stiffness and reduced center shift, which will benefit the control system and calibration procedure. A 2-DOF flexure mechanism is thus proposed by taking the practical application into account, such as manufacturability, performances of sensor and actuator. The finite element analysis (FEA) is carried out to verify the validation of design. Finally, the experiment is implemented and the results show a high accuracy: the error is less than 2.4g·mm even though the payload is up to 7kg and the unbalance moment is 100g·mm.
Advanced Parallel Actuation of a Serial Robotic Leg
Authors: Cahill Nathan , Holgate Matthew , Schroeder Kyle , Sugar Thomas G.
Published: December 2016

Advanced actuation methods are needed in legged robots in order to build robust and efficient robotic systems. State of the art robots either consume much more energy than their biological counterparts or are dramatically less mobile. Advanced actuation methods are necessary to achieve both efficiency and mobility. Many highly mobile legged robots are actuated in serial, but serial actuation has many known weaknesses. This research explores a new and promising method of actuation that is a hybrid of serial and parallel actuation. This method is able to draw from the large body of research conducted on parallel manipulators over the last several decades. This research has shown that parallel manipulators can offer many advantages over serial arms including: smaller mobile mass, more rigidity, faster end effector speeds, and large force capacity. All of these advantages are well suited for the requirements of legged robots. In this paper, the authors detail the implementation of this advanced actuation method from conceptualization to the first stages of testing. It details the choice of configuration, which was important, and somewhat counter intuitive. It also walks through the kinematic solutions, showing relatively simple solutions to challenging problems. The goal of the work is to use multiple, small motors in parallel to actuate the hip and the knee. In this way, during the stance phase of gait, multiple motors can be used in parallel to provide a powerful burst for push-off. Our two-link parallel structure allows the motors to cross multiple joints and therefore can be used to actuate several joints at once. In addition, by mounting motors at the base, the inertia of the leg is greatly reduced.B@Creating a fast, efficient leg structure is the first step in our project. The higher level goal of this research is to create a quadruped robot that is designed for efficient and fast running. The novel leg structure described in this paper will be capable of the types of motions associated with high speed gait. The robot needs to be capable of both high speed motions and high force output, without being excessively heavy. It should also be capable of accurate three dimensional control, and meet certain manipulability criterion. In this paper we show a functional and promising 3D printed leg prototype. This paper will provide a detailed description of this unique approach to actuation. It will also show the solution to the kinematic equations. Finally, as a proof of concept, the leg was moved in a gait pattern over a treadmill.
Data Driven Parametrization for Flexible Airfoils and Predictive Aerodynamics
Authors: Venkataraman P.
Published: December 2016

NASA achieved an important milestone in aircraft design the past year by flight testing a shapeshifting wing. The design moved the rear region of the wing through large deflection to provide flap operation for takeoff and landing. The next step is inflight surface modification of the entire wing. Underlying the three dimensional wing is the two-dimensional airfoil shape that anchors the wing aerodynamic performance. Many parametric definition of airfoils have been used for optimizing airfoil and wing aerodynamics but these analysis were made for fixed wing configurations. For flexible airfoils, it is important to recognize that the lofting of shapes in flight will happen around a parent airfoil. From a practical perspective it is likely that only a narrow range of shapes will be possible because of limited actuator locations. With this in mind a new Bézier parameterization scheme is introduced that can reproduce current airfoils with the assurance that original aerodynamics is maintained if not improved. Two Bézier curves are used to define the airfoil. One for the top surface and the other for the bottom surface. It is shown that this parametrization lends itself to fixed abscissa placement of control points for all airfoils, identifying possible actuator locations. Bézier curves change globally to local variation in geometry so a few points can generate an effective flexible airfoil. Coupling these changes with a simple analysis program can easily generate aerodynamic sensitivity information to physical shape changes based on the changes in a limited set of control points. This will provide the ability to create a shape based on a new aerodynamic demand while in flight. This paper presents the development of the parameterization scheme only.
Using Rapid Manufacturability Analysis Tools to Enhance Design-for-Manufacturing Training in Engineering Education
Authors: Lynn Roby , Jablokow Kathryn , Reddy Nithin , Saldana Christopher , Tucker Tommy , Simpson Timothy W. , Kurfess Thomas , Williams Christopher
Published: December 2016

Engineering students are often unaware of manufacturing challenges introduced during the design process. Students tend to design parts that are either very difficult or impossible to manufacture because they are unaware of the intricacies and limitations of the manufacturing processes available. Design for manufacturability (DFM) education must be improved to help address this issue. This work discusses a vision for the implementation of a rapid method for facilitating DFM education in terms of subtractive and additive manufacturing processes. The goal is to teach students about how their designs impact the ease and cost of manufacturing, in addition to giving them knowledge and confidence to move fluidly between additive and subtractive manufacturing mindsets. For subtractive manufacturing, this is accomplished through a high-performance-computing accelerated and parallelized trajectory planning software package that enables students to visualize the subtractive manufacturability of the parts they design as rapidly as they get feedback when using additive manufacturing processes. Implementation of the subtractive manufacturability analysis tool in a sophomore-level design class is presented, along with the assessment of the students’ conceptual manufacturing-related understanding.
Multi-Objective Optimal Design of Functionally Gradient Materials
Authors: Garland Anthony , Fadel Georges
Published: December 2016

The objective of this research is to optimally design both the topology and material distribution of functionally gradient material objects while considering more than one objective. Many techniques exist for both topology optimization and optimal placement of functionally gradient material within a single object, but combining the two is challenging. In addition, gradient materials allow customization of individual regions of a single part in order to achieve conflicting objectives or constraints. This paper shows a technique for concurrent topology and material gradient optimization within a single part while considering two conflicting objectives. The algorithm is applied to a standard topology optimization problem. The resulting gradient material designs have regions with distinct functionality and the material in these regions is chosen based on the regions function. In addition, a comparison of the gradient material design and a corresponding homogenous material design shows a significant improvement in the objective value for the gradient material design.
Development of an Integrated Simulation System for Design of Speech-Centric Multimodal Human-Machine Interfaces in an Automotive Cockpit Environment
Authors: Chen Yifan , Tonshal Basavaraj , Rankin James , Feng Fred
Published: December 2016

In the past two decades, various CAE technologies and tools have been developed for design, development and specification of the graphical user interface (GUI) of consumer products both in and outside the automotive industry. The growing trend of deploying speech interfaces by automotive manufacturers and the resulting usage of speech requires that the work be extended to speech interface modeling — an area where both technologies and methodologies are lacking.

This paper presents our recent work aimed at developing a speech interface integrated with an existing GUI modeling system. A multi-contour seat was utilized as the testbed for the work. Our prototype allows one to adjust the multi-contour seat with a touchscreen GUI, a steering wheel mounted button coupled with an instrument cluster display, or a speech interface.

The speech interface modeling began with an initial language model, which was developed by interviewing both the experts and novice users. The interview yielded a base corpus and necessary linguistic information for an initial speech grammar model and dialog strategy. After the module was developed it was integrated into the exiting GUI modeling system, in a way that the human voice is treated as a standard input for the system, similar to a press on the touchscreen. The multimodal prototype was used for two customer clinics. In each clinic, we asked a subject to adjust the multi-contour seat using different modalities, including the touchscreen, steering wheel mounted buttons, and the speech interface. We collected both objective and subjective data, including task completion time and customer feedback. Based on the clinic results, we refined both the language model and dialogue strategy. Our work has proven effective for developing a speech-centric, multimodal human machine interface.
Environmental Impact Assessment of Product Lifespan: The Role of Consumer’s Repair Behavior and Critical Components Deterioration
Authors: Sabbaghi Mostafa , Behdad Sara
Published: December 2016

Consumers might be willing to repair their broken devices as long as the associated repair costs do not exceed an undesirable threshold. However, in many cases the technological obsolescence actuates consumers to retire old devices and replace them with new ones rather than extending the product lifecycle through repair. In this paper, we aim to investigate the impact of components’ deterioration profiles and consumers’ repair decisions on the lifespan of devices, and then assesse the anticipated life cycle environmental impacts. A Monte Carlo simulation is developed to estimate the life cycle characteristics such as the average lifespan, the number of failed components’ replacement, and the total repair cost per cycle for a laptop computer. The lifecycle characteristics estimated from simulation model further have been used in a Life Cycle Assessment (LCA) study to quantify the environmental impact associated with different design scenarios. The results reveal the impact of product design as well as consumers’ repair decisions on the product lifespan and the corresponding environmental impacts.
Tolerance Allocation and Calibration With Limited Empirical Data
Authors: v. Beek Anton , Li Mian
Published: December 2016

Uncertainties are inherent to the physical world, which has made them a prominent field of research. They manifest themselves in many fields of engineering, one of which is known as tolerance analysis, where engineers attempt to predict system performance affected by the tolerance through analytical models. Ordinarily, discrepancies between analytical and experimental models are overcome by calibration techniques, using experimental data. Acquiring experimental data becomes a monetary expensive endeavor, when performed on assemblies with relative large design parameters. This work presents a methodology to formulate and calibrate analytical models, using Bayesian inference and Gaussian processes. The advantage of this methodology is that it uses a single set of overall performance experimental data, with a more accurate result than conventional methods. Subsidiary to the proposed methodology is a case study, vindicating as well as illustrating its transcendence from the confining extremities delineated by the panoply of current tolerance analysis and calibration techniques.
A Survey of Cloud-Based Design and Engineering Analysis Software Tools
Authors: Wu Dazhong , Terpenny Janis , Schaefer Dirk
Published: December 2016

In recent years, industrial nations around the globe have invested heavily in new technologies, software, and services to advance digital design and engineering analysis using the digital thread, data analytics, and high performance computing. Many of these initiatives such as Cloud-Based Design and Engineering analysis (CBDEA) fall under the umbrella of what has become known as Industry 4.0 or Industrial Internet. While an increasing number of companies are developing or already offering commercial cloud-based software packages and services for digital design and engineering analysis, little work has been reported on analyzing and documenting the related state-of-the-art as well as identifying potentially critical research gaps to be addressed in advancing this rapidly growing field. The objective of this paper is to present a state-of-the-art review of digital design and engineering analysis software and services that are currently available on the cloud. The main focus of this paper is on assessing the extent to which design and engineering analysis can already be performed based on the software and services accessed through the cloud. In addition, the key capabilities and benefits of these software packages and services are discussed. Based on the assessment of the core features of commercial CBDEA software and service packages, results suggest that almost all phases of a typical design and engineering analysis process can indeed already be conducted through cloud-based software tools and services.
Parameter Characterization for Elastic Energy Absorption of an Embedded Corrugated Wave Padding Concept
Authors: Tolman Sean S. , Beatty Amanda , Bowden Anton E. , Howell Larry L.
Published: December 2016

The parameters of an innovative padding concept were investigated using Finite Element Analyses (FEA) and physical testing. The concept relies on a compliant corrugation embedded in an elastic foam to provide stiffness for force distribution and elastic deformation for energy absorption. The shape of the corrugation cross section was explored as well as the wavelength and amplitude by employing a full factorial design of experiments. FEA results were used to choose designs for prototyping and physical testing. The results of the physical tests were consistent with the FEA predictions although the FEA tended to underestimate the peak pressure compared to the physical tests. A performance metric is proposed to compare different padding configurations. The concept shows promise for sports padding applications. It may allow for designs which are smaller, more lightweight, and move better with an athlete than current technologies yet still provide the necessary protective functions.