bluuebunny/crossref_metadata_2025 huggingface dataset:
Tolerance Specification and Related Issues for Additively Manufactured Products
Authors: Ameta Gaurav , Witherell Paul , Moylan Shawn , Lipman Robert
Published: January 2016

Additive manufacturing (AM) has gained increased attention in the last decade as a versatile manufacturing process for customized products. AM processes can create complex free-form shapes, introducing features such as internal cavities and lattices. These complex geometries are either not feasible or very costly with traditional manufacturing processes. This creates new challenges in maintaining and communicating dimensional and geometric accuracy of parts produced. In order to manufacture a product that meets functional needs, the specification of those needs through geometry, material and tolerances is necessary. This paper surveys the current state and needs of geometry related accuracy specification mechanisms for AM, including a review of specification standards such as ASME Y14.5 and ISO 1101. Emerging AM-related tolerancing challenges are identified, and a potential plan of action is put forth for addressing those challenges.

Various issues highlighted in this paper are classified as (a) AM-driven specification issues and (b) specification issues highlighted by the versatility of AM processes. AM-driven specification issues include build direction, layer thickness, support structure related specification, and scan/track direction. Specification issues highlighted by the versatility of AM processes include, region-based tolerances for complex freeform surfaces, tolerancing internal functional features, tolerancing lattice and infills. Basic methods of solving these specification issues are also highlighted.
How Can DFM Help the Study of Neuroanatomy?
Authors: Pandey Vijitashwa , Wolfe James , Shukla Vipul
Published: January 2016

Neuroanatomy is an essential course for healthcare students and imparts knowledge regarding the structure of the human nervous system. Its study requires calling upon many skills from students as well as educators. Particularly, challenging is to understand 3-dimensional structures and their relative positions and interfaces from primarily 2-dimensional images and MRI scans. Use of multiple modalities in teaching has been proposed, particularly supplementation of existing teaching methods with plastinated versions of actual brains. While the benefits of using plastinated specimens are many, it is a labor-intensive process that results in a relatively fragile specimen. Furthermore, any time idiosyncrasies of a specimen make it especially valuable, plastination is limited, because it results in only one specimen. To alleviate these issues, the authors propose scanning and reproduction of these samples using digital modeling and manufacturing techniques focused particularly on 3-D printing. In the context of converting from a purely preservation process to one of replication, it becomes immediately clear that the problem of proper mass reproduction, takes on a Design for Manufacture (DFM) construct, particularly, a design for assembly/disassembly/modularity shape. We show how this problem can be approached within the context of DFM, posed as a mathematical optimization problem and present preliminary results from our experiments.
Modeling the Lamination of a Multilayered Tape Cast Ceramic Component With Fugitive Phases Before Sintering
Authors: Wimmer Stephanie A. , DeGiorgi Virginia G. , Gorzkowski Edward
Published: January 2016

A small finished ceramic component with micro-channels or other complex geometry requires a high degree of dimensional accuracy. The accuracy of the finished ceramic component depends upon the accuracy of the unfired ceramic body before sintering. One approach to creating micro-channels in ceramics is the fugitive phase approach. In this approach a sacrificial material is placed within the unfired ceramic to form channels or voids. The fugitive phase is removed or sacrificed during the subsequent sintering. For this paper, the authors examine the lamination step of the fugitive phase approach computationally. In the lamination step layers of unfired tape cast ceramic and layers of fugitive phase material are pressed together before sintering. The geometry examined in this paper is a quarter-symmetry model of a ten ceramic layer and nine fugitive phase layer structure. Three dimensional modeling is used to capture out of plane motion, displacement of the fugitive phase pieces, viscoelastic deformation, and rebounding when the layered structure is removed from the die press. The unfired ceramic is modeled as tape cast mullite and the fugitive phase is paper. The fugitive phase is modeled as linear elastic while the unfired ceramic is modeled as viscoelastic at a range of temperatures. The authors examine the filling of voids, pressure gradients, and conditions during unloading.
A Preliminary Process for Origami-Adapted Design
Authors: Morgan Jessica , Magleby Spencer P. , Lang Robert J. , Howell Larry L.
Published: January 2016

The ancient art of origami has several attributes that are desirable in the design of engineered products such as deployability, stowability, and flat sheet manufacturing. Origami-adapted design aspires to transform the characteristics of an origami paper model into a usable product while maintaining functionality. Engineers have managed to design several origami-adapted products that are innovative in their respective fields. Despite the existence of these origami-adapted products, the process of origami-adapted design is still not well understood. This research seeks to develop an understanding of the origami-adapted design process, the steps involved, and the necessary tools with the goal of promoting the future development of additional origami-adapted products.
Predicting the Probability of Slip in Gait: Ramp Walking
Authors: Gragg Jared
Published: January 2016

When predicting the probability of a slip in gait, previous researchers have only considered level gait. There are no known attempts to apply probabilistic theory to predict the probability of a slip on ramped surfaces, even though there is a larger friction requirement for ramp gait compared to level gait. It is shown that when predicting the likelihood of a slip in ramp gait, the maximum value of the required coefficient of friction (RCOF) over the entire step must be considered. This is in contrast to level gait, where only one of the local maxima of the RCOF time profile is considered. This study predicts the probability of slip in gait for both up-slope gait and down-slope gait and discusses the major differences between the two. In general, it is found that up-slope gait has a higher potential for slip compared to down-slope gait and level gait.
Kinematic Analysis of Spherical Four-Bar Linkages via the Inflection Cubic and Thales Ellipse
Authors: Figliolini Giorgio , Angeles Jorge
Published: January 2016

The subject of this paper is the formulation of a specific algorithm for the kinematic analysis of spherical four-bar linkages via the inflection spherical cubic and spherical Thales ellipse by devoting particular attention to the crossed four-bar linkage (anti-parallelogram).

Moreover, both the inflection and the elliptic cones, which represent the equivalent of the Bresse cylinders of the planar case in three-dimensions, are obtained by showing the particular properties of the spherical motion in terms of the curvature of a coupler curve and both the velocity and acceleration vector fields.

Of special interest are also the cases in which the three acceleration poles coincide at one unique point or in two plus one, which depends on the intersections of two spherical curves of third and second degree.
Facilitating Multiple-Objective Decision-Making for Advanced Manufacturing: A Knowledge Representation and Computational Active Learning-Based Simulation Framework
Authors: Qu Shuhui , Jian Weiwen , Chu Tianshu , Wang Jie
Published: January 2016

Due to the rapid development of information technology and the impetus for more efficient and adaptive manufacturing processes, the concept of advanced manufacturing has become an increasingly prominent research topic across academia and industry in recent years. One critical aspect of advanced manufacturing is how to optimally cope with the complexities of multiple-objective decision-making to implement advanced manufacturing technologies with currently available enterprise resources and the realistic manufacturing conditions of a company. Generally, to successfully fulfill an advanced manufacturing plan, decision-makers must align short-term objectives with long-term strategies. In addition, the decision-making process usually has to prioritize multiple-objective goals under a considerable number of uncertainties. This requirement presents new challenges for both planning and implementing advanced manufacturing technologies, and thus calls for new approaches for to better support such tasks. This paper proposes a knowledge representation and computational active learning-based framework for dealing with complex, multiple-objective decision-making problems for advanced manufacturing under realistic conditions. Through this study, we hope to shed light on using a simulation framework for multiple-objective decision support, thereby providing an alternative for manufacturing enterprises, which could lead to an acceptable optimal decision with reasonable cost and accuracy. First, we describe the scope of an advanced manufacturing system for industrial manufacturing. Next, we introduce systematic analysis of the complexities of the decision-making to implement advanced manufacturing. Finally, we propose a simulation model for the decision-making and formulate a computational active learning-based framework to efficiently compute goal priorities for multiple-objective decision-making. We validate the framework by presenting a simulation of decision-making.
Development of a Part-Focused Manufacturing Process Ontology: Exploring Use and Applications
Authors: Mesmer Lucas , Olewnik Andrew
Published: January 2016

Numerous ontologies have been introduced to represent and activate engineering knowledge across the development process. However, many of the ontologies in the manufacturing domain provide limited usability for individuals with limited knowledge of manufacturing processes available within the domain. Similarly, web-based e-sourcing portals lack the ability to adequately pair components whose developers have limited knowledge of manufacturing processes with manufacturers who are able to produce their product. Motivated by these current gaps, an ontology is proposed which is designed to enable both users with a limited knowledge and those with a preexisting knowledge of manufacturing to identify potential processes. The Part-focused Manufacturing Process Ontology (PMPO) is designed around the concept that manufacturing processes can be selected based upon desired features and attributes of a component/product. This differs from past ontologies that model the manufacturing process domain on the characteristics of the resources utilized during the process. Further, the ontology is populated with some manufacturer data and its functionality demonstrated using various example situations.
Improving Senior Capstone Design Student Performance Through Integration of Presentation Intervention Plan
Authors: Bessette Amanda , Morkos Beshoy , Sangelkar Shraddha
Published: January 2016

This paper presents the findings of a study comparing the motivational factors and performance of two mechanical engineering senior capstone design course cohorts: 2014 and 2015 students. The study measures the motivation of students throughout capstone, a non-traditional course, and the impacts motivation had on their course performance (peer evaluations and team grade). The second cohort participated in an intervention plan during a design methodologies course completed the semester prior to senior capstone design. Quantitative data was collected at both the beginning and end of the course; whereas, qualitative data was collected at the end of the course. Our method utilizes an adapted version of the Motivational Student Learning Questionnaire (MSLQ). The survey asks a variety of questions to measure the performance and motivation levels of the student. Performance factors studied are cognitive value and self-regulation. Motivation factors include presentation anxiety, intrinsic value, and self-efficacy. Statistical analysis is performed among the factors, cohort populations, and within the population (male versus females and domestic versus international) to identify if a correlation exists with student course performance. Amongst other findings, the results indicate the student’s experienced positive change due to participation in the intervention plan.
A Hybrid Statistical Method for Accurate Prediction of Supplier Delivery Times of Aircraft Engine Parts
Authors: Banerjee Ashis Gopal , Yund Walter , Yang Dan , Koudal Peter , Carbone John , Salvo Joseph
Published: January 2016

Aircraft engine assembly operations require thousands of parts provided by several geographically distributed suppliers. A majority of the operation steps are sequential, necessitating the availability of all the parts at appropriate times for these steps to be completed successfully. Thus, being able to accurately predict the availabilities of parts based on supplier deliveries is critical to minimizing the delays in meeting the customer demands. However, such accurate prediction is challenging due to the large lead times of these parts, limited knowledge of supplier capacities and capabilities, macroeconomic trends affecting material procurement and transportation times, and unreliable delivery date estimates provided by the suppliers themselves. We address these challenges by developing a statistical method that learns a hybrid stepwise regression — generalized multivariate gamma distribution model from historical transactional data on closed part purchase orders and is able to infer part delivery dates sufficiently before the supplier-promised delivery dates for open purchase orders. The hybrid form of the model makes it robust to data quality and short-term temporal effects as well as biased toward overestimating rather than underestimating the part delivery dates. Test results on real-world purchase orders demonstrate effective performance with low prediction errors and constantly high ratios of true positive to false positive predictions.
Performance Comparison of a Bulk Thermoelectric Cooler With a Hybrid Device Architecture
Authors: Antonik Margaret , Ferguson Scott M. , O’Connor Brendan T.
Published: January 2016

This paper compares the economic viability and performance outcomes of two different thermoelectric device architectures to determine the advantages and appropriate use of each configuration. Hybrid thermoelectric coolers employ thin-film thermoelectric materials sandwiched between a plastic substrate and formed into a corrugated structure. Roll-to-roll manufacturing and low-cost polymer materials offer a cost advantage to the hybrid architecture at the sacrifice of performance capabilities while conventional bulk devices offer increased performance at a higher cost. Performance characteristics and cost information are developed for both hybrid and conventional bulk single-stage thermoelectric modules. The design variables include device geometry, electrical current input, and thermoelectric material type. The trade-offs between cooling performance and cost will be explored and the thermoelectric system configuration analyzed for both hybrid and conventional bulk thermoelectric coolers.
Effect of Redundant Actuation on the Mobility of Wheeled Robots on Unstructured Terrain
Authors: Ghotbi Bahareh , González Francisco , Kövecses Jozsef , Angeles Jorge
Published: January 2016

Improving the mobility of wheeled robots operating on unstructured terrain is a challenging task that can be approached in different ways. Enhanced mobility results in the vehicle being able to successfully negotiate slopes and obstacles, expanding the range of missions that can be undertaken and reducing the risk of losing or damaging the robot. This goal is directly related to optimizing the way in which traction force is developed at the wheel-terrain contact interfaces. Several strategies to achieve this objective, including traction control algorithms and reconfiguration, have been proposed in the literature. In this work, internal actuation is explored as a means to obtain better mobility on soft and irregular terrain. The use of this technique is demonstrated with a rover prototype in three maneuvers, namely flat soft terrain traverse, slope climbing on soft terrain, and negotiation of a step obstacle. Results show that redundant actuation can be used to improve the behavior of the vehicle, for optimum mobility on soft and irregular terrain.
Kinematic Analysis of a Mobile Robot Performing Manufacturing Tasks on Non-Planar Surfaces
Authors: Qualls Joshua , Canfield Stephen , Hill Tristan , Shibakov Alexander
Published: January 2016

As mobile robotic systems advance, they become viable technologies for automating manufacturing processes in fields that traditionally have not seen much automation. Such fields include shipbuilding or windmill, tank, and pipeline construction. In many cases, these mobile robots must operate in climbing configurations and on non-planar surfaces due to the unstructured nature of these manufacturing tasks. Unit operations are commonly considered in a planar context, but in practice are performed on generally non-planar surfaces. One such example is welding a seam along a non-flat ship hull; these surfaces consist of common geometric shapes such as cylinders or spheres. This paper will present a kinematic analysis of one mobile robot topology performing specified tasks on cylindrical surfaces. The analysis will define a method to determine the robot path on a work-piece surface as well as the configuration joint parameters along when the motion is prescribed in local tool space coordinates. This method assumes that the robot operates following the no-slip, pure roll conditions. The effort is motivated by a practical application of welding on steel hulls or other surfaces and the results will be compared with these empirical experiences. A discussion of how these results can be used to guide future design of mobile robot platforms for manufacturing is provided.
Combining Anthropometric Data and Consumer Review Content to Inform Design for Human Variability
Authors: Ferguson Taylor , Greene Melissa , Repetti Frank , Lewis Kemper , Behdad Sara
Published: January 2016

In this paper, we strive to combine concepts from the field of ergonomics with techniques from design analytics in order to inform the specifications of a product, such that a designer can create products that are both universal and well-received by consumers. While the ergonomic guidelines dictated by anthropometric data can provide a broad target range for design features, consumer reviews of previous iterations of similar products can narrow the design further, within that given range, to pinpoint a more effective design. We establish a general, ergonomically-centered set of cue-phrases to identify and extract useful information from online reviews, after which this information can be coupled with anthropometric measurements to produce more accurate product dimensions and features. A new metric, the Frequency and Accuracy Summation (FAS) Number is also introduced, as a means to predict the likelihood that a cue-phrase will yield useful results. The usefulness of these cue-phrases as well as the utility of combining consumer review content with anthropometric data sets are then tested in a case study centered on the design of a new and more universal “ear bud” headphone. Using the established cue-phrases, reviews of an existing product are processed such that problem components could be targeted in the new design. The information that was gleaned from those reviews is then paired with actual human ear measurements to propose a new, hypothetical product design that is more ergonomically sound and universal.
Automated Concept Generation Based on Function-Form Synthesis
Authors: Kang Sung Woo , Tucker Conrad S.
Published: January 2016

This work hypothesizes that enhancing next generation products’ distinctiveness through function-form synthesis results in feasible design concepts for designers. A data mining driven methodology that searches for novel function and form candidates suitable to include in next generation product design is introduced in this work. The methodology employs a topic modeling algorithm to search for functional relationships between the current product design and designs from related/unrelated domains. Combining the current product design and candidate products’ form and function, which is acquired from related/unrelated domains, generates next generation design concepts. These resulting design concepts are not only distinct from their parent designs but are also likely to be implemented in the real world by containing novel functions and form features. A hybrid marine model, which is differentiated from both the current design and candidate products in related/unrelated domains, is introduced in the case study in order to demonstrate the proposed methodology’s potential to develop concepts for novel product domains. By comparing the form and function similarity values between generated design concepts, an existing hybrid marine model (Wing In Ground effect ship: WIG), and source products, this research verifies the feasibility of these design concepts.
Human Factor Study in Gesture Based CAD Environment
Authors: Pareek Shrey , Sharma Vaibhav , Esfahani Ehsan T.
Published: January 2016

This study proposes a gesture based CAD interface that uses pose, position, velocity and direction of fingers as input data in order to draw, extrude, scale, translate and rotate an object in the 3D space. The system allows the user to generate basic geometrical primitives and advanced geometries (geometries that cannot be realized using the CSG primitives) and to perform basic CAD operations described above. As opposed to traditional systems wherein path based gestures are used to carry out operations, the proposed system uses switches that operate on simple binary principles thus reducing the computational cost of the system by eliminating the use of a classifier scheme to a high extent. A user study involving 10 subjects is also presented in order to determine the qualitative and quantitative efficacy of the proposed system.
Synthesis of a 10-Bar Linkage to Guide the Gait Cycle of the Human Leg
Authors: Tsuge Brandon Y. , McCarthy J. Michael
Published: January 2016

This paper uses path synthesis techniques to design four-bar linkage modules to constrain the movement of a 3R chain. The result is a 10-bar linkage. The goal is to develop a design procedure for a robotic system that guides the human leg during the walking gait cycle. A 3R chain is designed to match the dimensions of a human leg and the two four-bar linkages are synthesized using 9 point path synthesis to constrain the trajectory of the ankle and the toe. Precision points are derived from a basis spline equation. A numerical example is given using data collected from a motion capture system.
Exploring Requirement Change Propagation Through the Physical and Functional Domain
Authors: Hein Phyo Htet , Menon Varun , Morkos Beshoy
Published: January 2016

Prior research performed by Morkos [1], culminated in the automated requirement change propagation prediction (ARCPP) tool which utilized natural language data in requirements to predict change propagation throughout a requirements document as a result of an initiating requirement change. Whereas the prior research proved requirements can be used to predict change propagation, the purpose of this case study is to understand why. Specifically, what parts of a requirement affect its ability to predict change propagation? This is performed by addressing two key research questions: (1) Is the requirement review depth affected by the number of relators selected to relate requirements and (2) What elements of a requirement are responsible for instigating change propagation, the physical (nouns) or functional (verbs) domain? The results of this study assist in understanding whether the physical or functional domain have a greater effect on the instigation of change propagation.

The results indicated that the review depth, an indicator of the performance of the ARCPP tool, is not affected by the number of relators, but rather by the ability of relators in relating the propagating relationships. Further, nouns are found to be more contributing to predicting change propagation in requirements. Therefore, the physical domain is more effective in predicting requirement change propagation than the functional domain.
Topology Optimization of Cellular Materials With Maximized Energy Absorption
Authors: Carstensen Josephine V. , Lotfi Reza , Guest James K. , Chen Wen , Schroers Jan
Published: January 2016

While topology optimization is typically employed for design at the component-level scale, it is increasingly being used to design the topology of high performance cellular materials. The design problem is posed as an optimization problem with governing unit cell and upscaling mechanics embedded in the formulation, and solved with formal mathematical programming. While design for linear elastic properties is generally well-established, this paper will discuss including nonlinear mechanics in the topology optimization formulation, also in the domain of cellular materials. In particular, the problem of maximizing total energy absorption of a cellular Bulk Metallic Glass material is considered and numerical and experimental analyses of the new design show that it has enhanced performance compared to conventional cellular topologies.
Using a Principal-Agent Model to Investigate Delegation in Systems Engineering
Authors: Vermillion Sean D. , Malak Richard J.
Published: January 2016

Delegation of decision authority is a fundamental characteristic of systems engineering problems. Engineers and managers at higher levels within the organization allocate responsibility and resources to other individuals through requirements flowdown and other processes. The prevalence of schedule slippages and budget overruns on systems engineering projects raises questions about the adequacy of and potential to improve existing methods. However, at present the community lacks a foundational understanding of these processes that would be valuable in identifying and validating candidate improvements to the systems engineering process. In this paper, we develop a conceptual modeling framework for delegation in systems engineering based on the principal-agent problem, a game-theoretic model of agent interaction across hierarchical levels. Several variations on the basic model are possible. We study the model and its variations on an illustrative example of a passenger vehicle engineering process. Numerical results highlight the impact of various assumptions, including whether engineers act normatively or according to proposed behavioral decision models. Implications and extensions are discussed, including the need for behavioral validation of engineering decision models and the potential to use the modeling framework to evaluate newly proposed delegation schemes.
Development and Preliminary Validation of a 50th Percentile Pedestrian Finite Element Model
Authors: Untaroiu Costin D. , Putnam Jacob B. , Schap Jeremy , Davis Matt L. , Gayzik F. Scott
Published: January 2016

Pedestrians represent one of the most vulnerable road users and comprise nearly 22% of the road crash related fatalities in the world. Therefore, protection of pedestrians in the car-to-pedestrian collisions (CPC) has recently generated increased attention with regulations which involve three subsystem tests for adult pedestrian protection (leg, thigh and head impact tests). The development of a finite element (FE) pedestrian model could be a better alternative that characterizes the whole-body response of vehicle–pedestrian interactions and assesses the pedestrian injuries. The main goal of this study was to develop and to preliminarily validate a FE model corresponding to a 50th male pedestrian in standing posture. The FE model mesh and defined material properties are based on the Global Human Body Modeling (GHBMC) 50th percentile male occupant model. The lower limb-pelvis and lumbar spine regions of the human model were preliminarily validated against the post mortem human surrogate (PMHS) test data recorded in four-point lateral knee bending tests, pelvic impact tests, and lumbar spine bending tests. Then, pedestrian-to-vehicle impact simulations were performed using the whole pedestrian model and the results were compared to corresponding pedestrian PMHS tests. Overall, the preliminary simulation results showed that lower leg response is close to the upper boundaries of PMHS corridors. The pedestrian kinematics predicted by the model was also in the overall range of test data obtained with PMHS with various anthropometries. In addition, the model shows capability to predict the most common injuries observed in pedestrian accidents. Generally, the validated pedestrian model may be used by safety researchers in the design of front ends of new vehicles in order to increase pedestrian protection.
Carbon Nanotube Micropillars for Strain Sensing
Authors: Lanzara Giulia
Published: January 2016

A miniaturized strain sensor based on carbon nanotube (CNTs) micropillars is presented. The micropillars consist of square shaped forests of oriented CNTs sitting on Pt electrodes. The study focused on the analysis of the electron transport mechanisms and their correlation with the device geometry and deformation modes for increasing compression states (up to nearly 80% axial compression). The electrical resistance was found to be nonlinearly related to the device deformation in compression and decompression (full cycle). All tested devices were sensitive to deformations for an extremely wide range of strain values (significantly higher than conventional sensors), with a superior sensitivity for ultra-small deformations which makes them ideal for nanoscale sensing. Finally, it is believed that the CNTs micropillars have the potential to lead to strain sensing devices with a tuneable sensitivity and sensing range capability since the electron transport properties were found to be influenced by the device geometry.
Optimal Allocation of Worker Hours to Competing Design Projects to Meet Value Growth Targets
Authors: Freiheit Theodor
Published: January 2016

Value creation is the motivating principle of lean product development processes. Set-based concurrent engineering has been proposed to improve product development efficiency and stimulate innovation. However, this approach can lead to inefficient resource utilization because it promotes the development of competitive designs, and effective worker time allocation is a real need in complex design projects. This paper looks at one aspect of resource allocation: optimally assigning limited manpower to competing design projects using a project value growth model that characterizes the translation of work-hours into developed value. While resource allocation methodologies have been proposed before, this paper adds to these efforts by including the lean principle of value together with worker capability when delivering project work and formulates the solution as a predictive control problem. The optimized allocation solution can give guidance to project managers if it is necessary to add overtime or change scheduled completion dates if target value growth is missed because of scarce resources.
Modeling and Simulation of Asteroid Capture Using a Deformable Membrane Capture Device
Authors: Grip Håvard Fjær , San Martin Miguel , Jain Abhinandan , Balaram Bob , Cameron Jonathan , Myint Steven
Published: January 2016

The National Aeronautics and Space Administration have recently been investigating a mission concept known as the Asteroid Redirect Mission, aimed at collecting a large amount of asteroid material and transporting it into lunar orbit for inspection by human astronauts. Of the two mission options that have been considered, one involves the capture of an entire near-Earth asteroid in the 10-m class by a robotic spacecraft. The spacecraft would first make contact with the asteroid through a deformable membrane, before securing it inside a large flexible bagging mechanism. In this paper we describe the development and implementation of a model designed for simulation of the capture process, which includes a low-complexity representation of the interaction dynamics.
Design of a Passively-Adaptive Three Degree-of-Freedom Multi-Legged Robot With Underactuated Legs
Authors: Kanner Oren Y. , Rojas Nicolás , Dollar Aaron M.
Published: January 2016

This paper discusses the design of a three degree-of-freedom (3-DOF) non-redundant walking robot with decoupled stance and propulsion locomotion phases that is exactly constrained in stance and utilizes adaptive underactuation to robustly traverse terrain of varying ground height. Legged robots with a large number of actuated degrees of freedom can actively adapt to rough terrain but often end up being kinematically overconstrained in stance, requiring complex redundant control schemes for effective locomotion. Those with fewer actuators generally use passive compliance to enhance their dynamic behavior at the cost of postural control and reliable ground clearance, and often inextricably link control of the propulsion of the robot with control of its posture. In this paper we show that the use of adaptive underactuation techniques with constraint-based design synthesis tools allows for lighter and simpler lower mobility legged robots that can adapt to the terrain below them during the swing phase yet remain stable during stance and that the decoupling of stance and propulsion can greatly simplify their control. Simulation results of the swing phase behavior of the proposed 3-DOF decoupled adaptive legged robot as well as proof-of-concept experiments with a prototype of its corresponding stance platform are presented and validate the suggested design framework.
Controlling the Movement of a TRR Spatial Chain With Coupled Six-Bar Function Generators for Biomimetic Motion
Authors: Plecnik Mark M. , McCarthy J. Michael
Published: January 2016

This paper describes a synthesis technique that constrains a spatial serial chain into a single degree-of-freedom mechanism using planar six-bar function generators. The synthesis process begins by specifying the target motion of a serial chain that is parameterized by time. The goal is to create a mechanism with a constant velocity rotary input that will achieve that motion. To do this we solve the inverse kinematics equations to find functions of each serial joint angle with respect to time. Since a constant velocity input is desired, time is proportional to the angle of the input link, and each serial joint angle can be expressed as functions of the input angle. This poses a separate function generator problem to control each joint of the serial chain. Function generators are linkages that coordinate their input and output angles. Each function is synthesized using a technique that finds 11 position Stephenson II linkages, which are then packaged onto the serial chain. Using pulleys and the scaling capabilities of function generating linkages, the final device can be packaged compactly. We describe this synthesis procedure through the design of a biomimetic device for reproducing a flapping wing motion.
Solid Mechanics Based Design and Optimization for Support Structure Generation in Stereolithography Based Additive Manufacturing
Authors: Zhao Guanglei , Zhou Chi , Das Sonjoy
Published: January 2016

Support structures are typically required to hold parts in place in various additive manufacturing processes. Design of support structure includes identifying both anchor locations and geometries. Extensive work has been done to optimize the anchor locations to reliably keep part in position, and minimize the contacting area as well as the total volume of the support structures. However, relatively few studies have been focused on the mechanical property analysis of the structure. In this paper, we proposed a novel design optimization method to identify the anchor geometry based on solid mechanics theory. Finite element analysis method is utilized to study the stress distribution on both the support structure and main part. Particle Swarm Optimization (PSO) algorithm with a novel constraining handling strategy is employed to optimize the design model. A gradient descent local search algorithm is utilized to quickly locate the global solution in the vicinity explored by PSO. The developed optimization framework is deployed on a bottom-up projection based Stereolithography process. The experimental results show that the optimized design can efficiently reduce the material used on support structure and marks left on the part.
Limitations in the Use of Small-Length Flexural Pivot in a Pseudo-Rigid-Body Model
Authors: Lodagala Vamsi , Karthik Krutika , Midha Ashok
Published: January 2016

This paper investigates the effective use of the pseudo-rigid-body model (PRBM) of a small-length flexural pivot (SLFP), examining its very definition, and providing helpful guidelines in the context of a compound compliant beam composed of both compliant and rigid segments. Traditionally, for convenience in modeling, the pseudo-rigid-body model of the small-length flexural pivot assumes the characteristic pivot to be placed at the center of the SLFP. It is also suggested that the length of the adjacent rigid segment is ten or more times larger than the length of the compliant segment. In recent times, a growing interest has been expressed to test this assumption and learn more about its limitations. This paper investigates the performance of the PRBM of the SLFP, for initially straight and initially curved compound compliant beams by varying the compliant to rigid segment length ratio. The error, defined by comparing the PRBM deflections with those obtained from the closed-form elliptic integral method, may be assigned an acceptable value in determining the limit value of the segment length ratio. Plots of the maximum deflection that may be obtained within an error limit of 3%, for various segment length ratios of a fixed-free, compound compliant beam are provided.
Fostering Diverse Analogical Transfer in Bio-Inspired Design
Authors: Nagel Jacquelyn K. S. , Schmidt Linda , Born Werner
Published: January 2016

Nature is a powerful resource for engineering designers. The natural world provides numerous cases for analogy and inspiration in engineering design. Transferring the valuable knowledge and inspiration gained from the biology domain to the engineering domain during concept generation is a somewhat disorganized process and relies heavily on the designers’ insight and background knowledge of many fields to make the necessary leaps between the domains. Furthermore, the novice designer approaching biology for inspiration tends to focus heavily on copying the visual attributes of a biological system to develop a solution that looks like the biological system rather than explore at deeper levels to uncover relationships that lead to the development of true analogies.

There are now well-known methods for teaching bioinspired design in engineering and the majority of methods prescribe the use of analogies in order to facilitate knowledge transfer, however, guidance in analogy formulation to foster the creative leaps is missing or ill defined. Thus little is known about how students use biological systems for design inspiration. This paper proposes categories for analogical knowledge transfer in bio-inspired design to foster and characterize diverse analogical knowledge transfer. The proposed analogy categories are used to describe the behavior seen in an engineering class. Results indicate that (1) single biological system provides multiple analogies that result in different engineering inspiration for design; (2) biological information from multiple categories is transferred during concept generation; and (3) non-physical characteristics may inspire more sophisticated engineering inspiration than those based on physical characteristics alone. Overall, the analogy data classification has resulted in a better understanding of analogical knowledge transfer during bio-inspired design and leads to best practices for teaching bio-inspired design to engineering students.
Mechanical Advantage of a Compliant Mechanism and Significant Factors Affecting it, Using the Pseudo-Rigid-Body Model Approach
Authors: Midha Ashok , Bapat Sushrut G. , Midha Prem
Published: January 2016

Although work related to mechanical advantage of compliant mechanisms has been presented almost two decades ago, unlike many rigid-body mechanism systems, this performance measure has seldom been used. In great part, the reasons are attributed to, one, the relatively recent development of and a lack of familiarity with this technology and, two, the complexity of the understanding and evaluation of mechanical advantage of compliant systems. In an effort to simplify the evaluation, this work uses the pseudo-rigid-body model (PRBM) of a compliant mechanism, along with traditional notions of power conservation and angular velocity ratios using instant centers. As a first step, the inherent compliance in the mechanism is neglected in determining its mechanical advantage, followed by considerations to optimize its structural configuration for enhancing its mechanical advantage. The PRBM methodology, which offers us a way to estimate the characteristic compliance of the mechanism, now enables its inclusion in determining the mechanical advantage of the compliant mechanism. Two significant factors affecting it are i) the structural configuration of the PRBM, and ii) the energy stored in compliant elements of the mechanism. Several case studies are presented, which suggest that minimizing the latter contribution relative to that of an optimized structural configuration may improve the mechanical advantage of a compliant mechanism. Nonetheless, its effect on the mechanical advantage cannot be neglected.
Tensegrity Form-Finding Using Generative Design Synthesis Approach
Authors: Hooshmand Amir , Campbell Matthew I.
Published: January 2016

The aim of this research is to produce large irregular tensegrity structures using a generative design synthesis approach. Unlike most of the form-finding methods, the approach does not require the description of the connectivity of the tensegrity structures to define the shape of the tensegrities. It uses graphs to represent the tensegrity structures, which allows a very fast generation of stable tensegrity solutions for a given design problem. The graph grammar interpreter, GraphSynth, is used to carry out graph transformations, which define different configurations for a given design problem. After generating the graphs, they are transformed into meaningful 3D shapes. The effectiveness and robustness of the proposed method is checked by solving a variety of test problems.
ARM-COMS for Entrainment Effect Enhancement in Remote Communication
Authors: Ito Teruaki , Watanabe Tomio
Published: January 2016

The remote communication systems allow us to enjoy the benefit of audio/video communication over the network. However, the communications based on these systems pose some open issues, such as lack of tele-presence, lack of entrainment in communication, etc. In order to tackle these issues, this study proposes an idea of remote individuals’ connection through augmented tele-presence systems called ARM-COMS: ARm-supported eMbodied COmmunication Monitor System. ARM-COMS is composed of a tablet PC as an ICT (Information and Communication Technology) device and a desktop robotic arm, which manipulates the tablet. ARM-COMS operates in two types of modes, or intelligent tablet mode (IT-mode) and intelligent avatar mode (IA-mode) to implement the three functions; namely, autonomous positioning (AP), autonomous entrainment movement (AEM), and autonomous entrainment positioning (AEP). This paper presents the basic concept of ARM-COMS and focuses on AEM function to accelerate the entrainment effect in remote communication.
Nonlinear Dynamics of Carbon Nanotubes Under Large Electrostatic Force
Authors: Xu Tiantian , Younis Mohammad I.
Published: January 2016

Because of the inherent nonlinearities involving the behavior of CNTs when excited by electrostatic forces, modeling and simulating their behavior is challenging. The complicated form of the electrostatic force describing the interaction of their cylindrical shape, forming upper electrodes, to lower electrodes poises serious computational challenges. This presents an obstacle against applying and using several nonlinear dynamics tools typically used to analyze the behavior of complicated nonlinear systems, such as shooting, continuation, and integrity analysis techniques. This works presents an attempt to resolve this issue. We present an investigation of the nonlinear dynamics of carbon nanotubes when actuated by large electrostatic forces. We study expanding the complicated form of the electrostatic force into enough number of terms of the Taylor series. Then, we utilize this form along with an Euler–Bernoulli beam model to study the static and dynamic behavior of CNTs. The geometric nonlinearity and the nonlinear electrostatic force are considered. An efficient reduced-order model (ROM) based on the Galerkin method is developed and utilized to simulate the static and dynamic responses of the CNTs. Several results are generated demonstrating softening and hardening behavior of the CNTs near their primary and secondary resonances. The effect of DC voltage load and AC voltage load on the nonlinearity has been studied. We also investigated the impact of initial slack level on the natural frequency and the nonlinearity. Small diameter and large initial slacked CNTs has been considered.
Topological Design of Parallel Hybrid Transmission With Electric Torque Support
Authors: Peng Zengxiong , Yuan Shihua , Hu Jibin , Gao Mingfei
Published: January 2016

In the last years hybrid Transmissions have spread worldwide in the automotive industry due to their excellent power performance and good fuel economy. The design of parallel hybrid automatic manual transmission (AMT) with electric torque support using one electric motor is a good solution of obtaining high transmission efficiency and low manufacturing cost. The gear pairs between the combustion engine (CE) shaft and electric motor (EM) shaft are assigned to form the new architecture of three degrees of freedom (DOFs) AMT with electric torque support, which provides several CE gears ratios and several EM gears ratios. All theoretical layouts of parallel hybrid AMT with three shafts are presented and classified into four types. And the synthesis of the gear ratios sequence is developed to satisfy power shifting. The gear ratios can be divided into direct gear ratio and generated gear ratio. The ratio design of generated gear is dependent on the ratio of the direct gears, so the design of gear ratio can be transformed into the solution of over-determined nonlinear equations. An algorithm of minimax solution for over-determined nonlinear equations is presented to design and evaluate gear ratios. The three-DOF three-shaft AMT with electric torque support are designed to obtain seven CE gear ratios. This paper helps to further the understanding of the systematic design of parallel hybrid AMT with electric torque support.