bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Performance of Check Valve at a Long Distance Pumping System
Authors: Bi Huili , Fan Honggang , Cao Bin , Xu Yu
Published: November 2019

Experimental investigations of dynamic characteristics of the check valve are a contribution work to provide boundary condition to check valve mathematical simulation. The closure process of the check valve was tested. The changing processes of inlet and outlet pressure were performed.

Based on the experiment system and the measured quantities, mathematical models were established to study the test. Numerical calculation was mainly focus on when valve starting to close and the closing characteristic time.

The paper simulated the different minimum velocities that the valve started to close at. Simulation results approximated to test data when the check valve started to close at a larger flow velocity and a shorter closing characteristic time. The closing characteristic time was discussed when check valves closing on a certain velocity.

Following the closure rule of check valve got during the simulation, the paper studied the check valve acting on a long distance pumping system. Two part contents were studied: only check valve arranged along pipeline, both air admission valve and check valves arranged.

Along the pipeline seven check valves were arranged, the pump power failure condition was calculated and check valves were closed because of the flow velocity decreased. The result showed negative pressure was large when installed just a finite number of check valves along pipeline.

Gas admission valves were arranged to negative pressure prevention. Two check valves were respectively arranged at the pump outlet and pipeline. The pressure transient peak at pump outlet will be dropped a lot with the check valve at pipeline closed; the maximum pressure transient peak along pipeline is appeared at check valve outlet on the pipeline under the pump power failure condition. The negative pressure in front pipes could be prevented by installing gas admission valve. Through the check valves and gas admission valves combined action, both the pressure and backflow were well controlled.
Model Based Determination of Size and Location of a Crack in a Rotor System Using Wavelet Transformation and Pattern Search Optimization
Authors: Vashisht Rajiv Kumar
Published: November 2019

Real rotor with multiple disks, ball bearings and flexible bearing supports has been considered in the present work. Reduced order model required for simulations of the dynamic system is developed using multi-objective genetic algorithms by matching its dynamic response with full order Finite Element Method based model. This enables us the possibility of including ball bearing dynamics as well as experimental data in model updating. In a rotating machinery, multiple types of faults can be expected during its service life, such as transverse breathing crack, looseness of bearing supports and unbalance. Rotor crack can be quantified by using the dynamic response of the rotor under coast up conditions in open loop situation using Pattern Search optimization. Wavelet transformations are used to denoise the signal and enhance the estimation accuracy.
Sparse Scaling Iterative Closest Point for Rail Profile Inspection
Authors: Yang Yue , Liu Long , Yi Bing
Published: November 2019

The accuracy of rail profile inspections is critical for guaranteeing transport security and rail maintenance, and hence the laser based rail profile inspection has been frequently used. However, there are two major challenges in practical applications: the distortion of the measured rail profile and the influences of noise and outliers. In this paper, the sparse scaling iterative closest point method is proposed for rail profile inspection. First, the existing challenges for processing the measured rail profile via a line laser sensor are generally described. After this, a robust registration energy function that evolves both the scale factor and lp norm is proposed for rail profile registration. Finally, the Hausdorff distance is adopted to visualize the matching results. The experiments indicate that the proposed method can both precisely rectify the distorted rail profile and avoid the influences of noise and outliers when compared with the conventional iterative closest point, sparse iterative closest point and reweighted-scaling closest point methods.
Smartphone As a Stand-Alone Device for Rendering, Visualization and Tracking for Use During Product Development in Virtual Reality (VR)
Authors: Mahboob Atif , Husung Stephan , Weber Christian , Liebal Andreas , Krömker Heidi
Published: November 2019

Product development process makes use of different models, methods and available technologies to validate product requirements at an early stage. Technologies like Virtual Reality (VR) and Augmented Reality (AR) are increasingly finding their application in industry and in the product development process. VR has the potential to support the product evaluation process. However, the costly preparation of VR scenes and the expensive hardware needed for the implementation greatly limits its use in the industry. Normally, the different VR content development and rendering softwares are application specific and offer very limited interoperability or reuse of created content. In addition, the needed hardware usually consists of dedicated visualization computers, tracking sensors, interaction devices and requires a fixed installation space. The motivation for the work presented in this paper is to reduce the preparation effort, hardware cost and remove the need for a fixed installation usually required by VR.

The High-End smartphones of today from almost all the manufacturers can facilitate the development and stand-alone execution of VR and AR applications. However, the major application of Smartphone Virtual Reality (SVR) is mainly in the entertainment industry i.e. VR-gaming or visualization applications etc. VR until today is thought to be a visualization technology that requires special hardware for its implementation. There are hardly any applications of SVR in the industry today mainly because of two reasons. First, the position tracking against the user movement in the virtual scene is not readily available in SVR. It is usually achieved by attaching additional tracking devices to smartphones. Secondly, the smartphones themselves are not perceived as high-performance devices suitable for industrial simulations.

This paper discusses a method for efficient preparation of VR-scene along with their behavior simulations and presents a novel SVR application that eliminates the need for expensive VR hardware. The challenges and the requirements from the SVR along with the possible solutions are discussed in detail. The presented SVR application includes product behavior simulation and wireless communication with a laptop. An example product along with its behavior simulation sums-up the application of SVR in the product development process. The position tracking in SVR is implemented and an experiment compares the precision of this position tracking with the tracking achieved by a Head Mounted Display (HMD). The experimental setup along with the achieved results are also discussed. A user survey conducted for the smartphone VR application and the feedback of this survey is also presented in this paper.
Three-Dimensional Spatial Meshing Quality Pre-Control of Harmonic Drive Based on Double-Circular-Arc Tooth Profile
Authors: Xie Faxiang , Zhang Jing , Han Yinan , Wu Canyuan , Zhao Zhengyang , Zhan Min
Published: November 2019

In the current harmonic drive tooth profile design, the three-dimensional spatial spline tooth meshing is not fully considered, which results in problems such as inconsistence of harmonic gearing backlash, low loading capacity, low transmission accuracy and even meshing tooth profile interference in actual machining of the harmonic reducer. Based on this, this paper proposes a harmonic drive meshing quality test method at extremely low input speed based on tooth profile of double–circular-arc profile (DCTP). And combined with the theory of spatial multi-tooth meshing, the corresponding pre-control of different tooth profile modification is analyzed. The optimized non-interference three-dimensional spatial tooth profile modification method is proposed, which effectively reduces its transmission error.
Sliding Mode Set-Point Control of a Three-DOF Cable-Suspended Parallel Robot With Uncertain Mass and Disturbances
Authors: Ren Ping , Sheng Xu
Published: November 2019

Cable-Suspended Parallel Robots (CSPRs) utilize winches and cables as the actuation scheme instead of rigid links, which renders them advantages of both parallel mechanisms and cable mechanisms. In this paper, a robust sliding mode controller was designed for a three-degree-of-freedom CSPR with uncertain end-effector mass and external disturbances. To control the motions of CSPRs is usually challenging due to the unidirectional constraints of cable tensions. Based on interval analysis, a set of analytical inequalities is obtained which establish the relationship between the cables’ tension constraints and the controller parameters. The sufficient conditions of the controller parameters satisfying the constraints are obtained for the set-point motion subject to uncertainties. Numerical simulations are presented to verify the effectiveness of the proposed approach.
Contour Scanning Method With Inner Supports for Micro-Shell Structural Strengthening Strategy Based on Two-Photon Polymerization Technology
Authors: Tseng Yu-Wen , Liao Chao-Yaug , Tseng Chin-Huang , Chen Po-Kai
Published: November 2019

The traditional two-photon polymerization manufacturing technology encounters two difficulties in fabricating submillimeter/micron-scale structures: excessively long fabrication time and weak structural strength, causing collapse of the structure. To solve these problems, this research first develops a new laser scanning path planning strategy, namely, the contour scanning method with inner supports. The concept is to reduce the fabrication time by manufacturing only submillimeter/micron structural shells as well as to generate the support structure below the horizontal area of the shell to enhance the structural strength. In this study, a method for generating a laser scanning path is presented, and a simple micro-cuboid and a micro-calcaneus with complex shape are fabricated to verify the proposed method. The method can effectively reduce the fabrication time and prevent submillimeter/micron structure collapse.
Identification of a Laboratory Slide Drilling Experiment: The Relationship Between the Top Drive Rotation and the Tool-Face Angle
Authors: Chen Kaidong , Zhong Xiaoyu , Cheng Zaibin , Lu Yingjie , Lu Qiuhai
Published: November 2019

Slide drilling refers to the technology of creating a predetermined non-vertical wellbore with a bent housing positive displacement motor (PDM). It is widely adopted in the area of directional drilling. In practical drilling operation, the top drive on the ground introduces an angular rotation to the top of the drill string, and the PDM at the bottom of the drill string rotates accordingly. When the bend is pointed to the desired direction, the adjustment of the PDM stops and the drill string slides without rotation to make a deviation. Up till now, the relationship between the top drive displacement and the direction of the bend, namely the tool-face angle (−180° ∼ 180°), is still unclear. In this research, an indoor slide drilling experiment is carried out, and the nonlinear relationship between the top drive input and the tool-face output is recorded. The hysteretic phenomenon observed is consistent with the in-field experience, and a single-input-single-output (SISO) system is established to describe this relationship. The Volterra/ Wiener neural network (VWNN) is introduced to identify this system, and provides a one-step prediction of the tool-face output. The predicted tool-face output is verified by the experiment data.
A Proposal for Digital Imaging and Communication in Product Engineering Using CT Data
Authors: Hofmann Dirk , Sembdner Philipp , Holtzhausen Stefan , Stelzer Ralph
Published: November 2019

The increasing complexity of products requires efficient computer-aided methods and tools in product development. Data and information from quality assurance, such as industrial computed tomography (iCT), are increasingly being used. With this technology it is possible to detect 3D information of internal structures and geometries and to use it for design and numerical issues within the product development.

The previous procedure for use CT data in the product development comprises several iterative step sequences. Starting first from an image stack a discrete model description, such as a STL file format (Standard Tessellation Language) is created. This data description can be used for numerous applications in the product development such as target-actual comparison in the component inspection. For information, which also exist during entry (f.e. production faults), there is no established process sequence. However, the characteristics on the errors can also contain causes for defects and should therefore take into account in product development. For this reason, a concept is presented in the following article to use CT data and additional information specifically for the product development. Using a continuous process chain between quality management (QM) and the product engineering this approach should be clarified. To integrate the description and characterization of the information an already existing standard will be used and extended accordingly.

An essential application of this approach is the component testing of additive manufactured parts by CT within the product development process. The combination of this Non-Destructive Testing (NDT)-Technology with the advantages of additive manufacturing processes such as the creation of internal structures makes a continuous process chain unavoidable. For this reason, an example of an additively manufactured impeller clarifies the approach.
Current State of the Art: Problem-Driven Multi-Functional Bio-Inspired Designs
Authors: Bhasin Devesh , McAdams Daniel A.
Published: November 2019

The development of multi-functional designs is one of the prime reasons to adopt bio-inspired design in engineering design. However, the development of multi-functional bio-inspired designs is mostly solution-driven, in the sense that an available multi-functional solution drives the search for a problem that can be solved by implementing the available solution. The solution-driven nature of the approach restricts the engineering designers to the use of the function combinations found in nature. On the other hand, a problem-driven approach to multi-functional designs allows the designers to form some combination of functions best suited for the problem at hand. However, few works exist in the literature that focus on the development of multi-functional bio-inspired solutions from a problem-driven perspective.

In this work, we analyze the existing works that aid the designers in combining multiple biological strategies to develop multi-functional bio-inspired designs. The analysis is carried out by comparing and contrasting the existing frameworks that support multi-functional bio-inspired design generation. The criteria of comparison are derived from the steps involved in the unified problem-driven biomimetic approach. In addition, we qualitatively compare the multi-functional bio-inspired designs developed using existing frameworks to the multi-functional designs existing in biology. Our aim is to explore the capabilities and limitations of current methods to support the generation multi-functional bio-inspired designs.
Integrated System Design and Control Optimization of Hybrid Electric Propulsion System Using a Bi-Level, Nested Approach
Authors: Chen Li , Dong Huachao , Dong Zuomin
Published: November 2019

Hybrid electric powertrain systems present as effective alternatives to traditional vehicle and marine propulsion means with improved fuel efficiency, as well as reduced greenhouse gas (GHG) emissions and air pollutants. In this study, a new integrated, model-based design and optimization method for hybrid electric propulsion system of a marine vessel (harbor tugboat) has been introduced. The sizes of key hybrid powertrain components, especially the Li-ion battery energy storage system (ESS), which can greatly affect the ship’s life-cycle cost (LCC), have been optimized using the fuel efficiency, emission and lifecycle cost model of the hybrid powertrain system. Moreover, the control strategies for the hybrid system, which is essential for achieving the minimum fuel consumption and extending battery life, are optimized. For a given powertrain architecture, the optimal design of a hybrid marine propulsion system involves two critical aspects: the optimal sizing of key powertrain components, and the optimal power control and energy management. In this work, a bi-level, nested optimization framework was proposed to address these two intricate problems jointly. The upper level optimization aims at component size optimization, while the lower level optimization carries out optimal operation control through dynamic programming (DP) to achieve the globally minimum fuel consumption and battery degradation for a given vessel load profile. The optimized Latin hypercube sampling (OLHS), Kriging and the widely used Expected Improvement (EI) online sampling criterion are used to carry out “small data” driven global optimization to solve this nested optimization problem. The obtained results showed significant reduction of the vessel LCC with the optimized hybrid electric powertrain system design and controls. Reduced engine size and operation time, as well as improved operation efficiency of the hybrid system also greatly decreased the GHG emissions compared to traditional mechanical propulsion.
Metaheuristic Tuning and Practical Implementation of a PID Controller Employing Genetic Algorithms
Authors: Angel Luis , Viola Jairo , Vega Mauro
Published: November 2019

PID controllers tuning is a complex task from the optimization perspective because it is a multiobjective optimization problem, which must ensure the accomplishment of a set of desired operating conditions of the closed-loop system as the overshoot, the settling time, and the steady state error. Employing metaheuristic optimization techniques is possible to find optimal solutions for the PID tuning multiobjective optimization problem with less computational cost. This paper presents the using of genetic algorithms as metaheuristic optimization technique for the tuning of a PID controller employed for the speed control of a motor-generator system. The genetic algorithm is designed to find the PID controller proportional, integral, and derivate terms that ensure the desired overshoot and settling time of the motor-generator system. The practical implementation of the PID controller is performed with a data acquisition card and the Matlab Stateflow toolbox. The proposed controller is contrasted with a PID controller tuned by the Internal Model Control technique. A robustness analysis is performed to evaluate the system response in the presence of the external disturbances. Obtained results shown that the PID controller tuned by genetic algorithm has a better response in the presence of external disturbances.
Visual Performance Evaluation of Helicopter Pilots in Vibrating Cockpit
Authors: Tamer Aykut , Zanoni Andrea , Cocco Alessandro , Masarati Pierangelo
Published: November 2019

Rotorcraft are known to suffer from relatively high levels of vibration as compared to their fixed-wing counterpart, due to exposure to significant vibratory load levels. Pilots usually operate in a vibrating cockpit, and hence can suffer from degradation of their instrument reading performance. Therefore, the expected level of degradation in visual performance should be estimated when there is room for design changes. The present work demonstrates the evaluation of visual vibration degradation of helicopter pilots using a modular analysis environment. Core elements are an aeroelastic helicopter model, a seat-cushion model, a detailed human biodynamics multibody model, and a simplified model of ocular dynamics, which are assembled into an overall model. The contribution of each component is examined using a figure of merit that includes both eye and instrument panel vibration.
Mobile Robot Obstacle Avoidance Based on Deep Reinforcement Learning
Authors: Feng Shumin , Ren Hailin , Wang Xinran , Ben-Tzvi Pinhas
Published: November 2019

Obstacle avoidance is one of the core problems in the field of mobile robot autonomous navigation. This paper aims to solve the obstacle avoidance problem using Deep Reinforcement Learning. In previous work, various mathematical models have been developed to plan collision-free paths for such robots. In contrast, our method enables the robot to learn by itself from its experiences, and then fit a mathematical model by updating the parameters of a neural network. The derived mathematical model is capable of choosing an action directly according to the input sensor data for the mobile robot. In this paper, we develop an obstacle avoidance framework based on deep reinforcement learning. A 3D simulator is designed as well to provide the training and testing environments. In addition, we developed and compared obstacle avoidance methods based on different Deep Reinforcement Learning strategies, such as Deep Q-Network (DQN), Double Deep Q-Network (DDQN) and DDQN with Prioritized Experience Replay (DDQN-PER) using our simulator.
Computational Design of Scheduling Strategies for Multi-Robot Cooperative 3D Printing
Authors: Poudel Laxmi , Zhou Wenchao , Sha Zhenghui
Published: November 2019

Cooperative 3D printing (C3DP) is a novel approach to additive manufacturing, where multiple printhead-carrying mobile robots work together cooperatively to print a desired part. The core of C3DP is the chunk-based printing strategy in which the desired part is first split into smaller chunks, and then the chunks are assigned to individual printing robots. These robots will work on the chunks simultaneously and in a scheduled sequence until the entire part is complete. Though promising, C3DP lacks proper framework that enables automatic chunking and scheduling given the available number of robots. In this study, we develop a computational framework that can automatically generate print schedule for specified number of chunks. The framework contains 1) a random generator that creates random print schedule using adjacency matrix which represents directed dependency tree (DDT) structure of chunks; 2) a set of geometric constraints against which the randomly generated schedules will be checked for validation; and 3) a printing time evaluation metric for comparing the performance of all valid schedules. With the developed framework, we present a case study by printing a large rectangular plate which has dimensions beyond what traditional desktop printers can print. The study showcases that our computation framework can successfully generate a variety of scheduling strategies for collision-free C3DP without any human interventions.
Belt-Drive Mechanics: Energy Losses in the Presence of Detachment Waves
Authors: Wu Yingdan , Leamy Michael J. , Varenberg Michael
Published: November 2019

The dissipative rolling friction moment in a simple belt-drive system is estimated both experimentally and computationally while taking into account the detachment events at the belt-pulley interface. Shear traction is estimated based on measurements of the shear strain along the contact arc. It is shown that the dissipative moment can be approximated by taking the difference between the shear traction and the load carried by the belt. A model is developed for analyzing the contributions of different components to this dissipative moment by considering both the volumetric and surface hysteresis losses. The computed rolling friction moment is found to be in good agreement with that estimated based on the experiments. It is also found that while the shear- and stretching-induced energy losses contribute the most to the dissipation in the belt drive system, the losses associated with the Schallamach waves of detachment make up a considerable portion of the dissipation in the driver case.
Design of Gradient Nanotwinned Metal Materials Using Adaptive Gaussian Process Based Surrogate Models
Authors: Zhou Haofei , Chen Xin , Li Yumeng
Published: November 2019

Inspired by gradient structures in the nature, Gradient Nanostructured (GNS) metals have emerged as a new class of materials with tunable microstructures. GNS metals can exhibit unique combinations of material properties in terms of ultrahigh strength, good tensile ductility and enhanced strain hardening, superior fatigue and wear resistance. However, it is still challenging to fully understand the fundamental gradient structure-property relationship, which hinders the rational design of GNS metals with optimized target properties. In this paper, we developed an adaptive design framework based on simulation-based surrogate modeling to investigate how the grain size gradient and twin thickness gradient affect the strength of GNS metals. The Gaussian Process (GP) based surrogate modeling technique with adaptive sequential sampling is employed for the development of surrogate models for the gradient structure-property relationship. The proposed adaptive design integrates physics-based simulation, surrogate modeling, uncertainty quantification and optimization, which can efficiently explore the design space and identify the optimized design of GNS metals with maximum strength using limited sampling data generated from high fidelity but computational expensive physics-based simulations.
Improving Cuckoo Search Algorithm With Mittag-Leffler Distribution
Authors: Wei Jiamin , Chen YangQuan , Yu Yongguang , Chen Yuquan
Published: November 2019

Cuckoo search (CS), as one of the recent nature-inspired metaheuristic algorithms, has proved to be an efficient approach due to the combination of Lévy flights, local search capabilities and guaranteed global convergence. CS uses Lévy flights in global random walk to explore the search space. The Lévy step is taken from the Lévy distribution which is a heavy-tailed probability distribution. In this case, a fraction of large steps are generated, which plays an important role in enhancing search capability of CS. Besides, although many foragers and wandering animals have been shown to follow a Lévy distribution of steps, investigation into the impact of other different heavy-tailed probability distributions on CS is still insufficient up to now. Based on the above considerations, we are motivated to apply the well-known Mittag-Leffler distribution to the standard CS algorithm, and proposed an improved cuckoo search algorithm (CSML) in this paper, where a more efficient search is supposed to take place in the search space thanks to the long jumps. In order to verify the performance of CSML, experiments are carried out on a test suite of 20 benchmark functions. In terms of the observations and results analysis, CSML can be regarded as a new potentially promising algorithm for solving optimization problems.
Interpreting Measures of Rarity and Novelty: Investigating Correlations Between Relative Infrequency and Perceived Ratings
Authors: Weaver Morgan B. , Caldwell Benjamin W. , Sheafer Vicki
Published: November 2019

Central to the struggle in design ideation research is the quantification of abstract and qualitative measures. Among these measures, creativity, originality, and novelty are some of the most subjective and generally disagreed upon constructs. In recent years in the design community, novelty has primarily been measured with two distinct styles of metrics: relative infrequency and perceived ratings. Relative infrequency captures how rare an idea is within an idea set for an objective representation of novelty, while ratings quantify the perceptions of appropriate judges for an intuitive understanding of novelty. This paper investigates the convergent validity between these two styles through the implementation of three previously published methods. Moderate convergent validity is shown between a measure of relative infrequency and perceived ratings leading to clear and meaningful recommendations for metrics in future research. However, the degree of disagreement warrants differentiation between the two styles regarding terminology and analysis. This study will aid in the research and interpretation of future studies of creativity in ideation.
Comparing Multifidelity Model Management Strategies for Multidisciplinary Design Optimization
Authors: Chell Brian , Hoffenson Steven , Blackburn Mark R.
Published: November 2019

Multifidelity optimization leverages the fast run times of low-fidelity models with the accuracy of high-fidelity models, in order to conserve computing resources while still reaching optimal solutions. This work focuses on the multidisciplinary multifidelity optimization of an unmanned aerial system model with finite element analysis and computational fluid dynamics simulations in-the-loop. A two-step process is used where the lower-fidelity models are optimized, and then the optimizer is used as a starting point for the higher-fidelity models. By starting the high-fidelity optimization routine at a nearly optimal section of the design space, the computing resources required for optimization are expected to decrease when using gradient-based algorithms. Results show that, at least in some cases, the multifidelity workflows save time over optimizing the original high fidelity model alone. However, the model management strategy did not find statistically significant differences between the differing optimization approaches when used on this test problem.
Evaluating the Potential of Design for Additive Manufacturing Heuristic Cards to Stimulate Novel Product Redesigns
Authors: Blösch-Paidosh Alexandra , Ahmed-Kristensen Saeema , Shea Kristina
Published: November 2019

Additive manufacturing (AM) affords those who wield it correctly the benefits of shape, material, hierarchical, and functional complexity. However, many engineers and designers lack the training and experience necessary to take full advantage of these benefits. They require training, tools, and methods to assist them in gaining the enhanced design freedom made possible by additive manufacturing. This work, which is an extension of the authors’ previous work, explores if design heuristics for AM, presented in a card-based format, are an effective mechanism for helping designers achieve the design freedoms enabled by AM. The effectiveness of these design heuristic cards is demonstrated in an experiment with 27 product design students, by showing that there is an increase in the number of unique capabilities of AM being utilized, an increase in the AM novelty, and an increase in the AM flexibility of the generated concepts, when given access to the cards. Additionally, similar to the previous work, an increase in the number of interpreted heuristics and AM modifications present in the participants’ designs when they are provided with the heuristic cards is shown. Comparisons are also made between 8-heuristic and 29-heuristic experiments, but no conclusive statements regarding these comparisons can be drawn. Further user studies are planned to confirm the efficacy of this format at enhancing the design freedoms achieved in group and team design scenarios.
Quasi-Static Curve Negotiation Analysis of Railway Vehicle Considering Nonlinear Air Suspension LV and DPV Flow Characteristics
Authors: Tanaka Takayuki , Sugiyama Hiroyuki
Published: November 2019

Accurate prediction of vehicle curve negotiation performance is critically important for evaluation of railway vehicle safety. Although multibody dynamics vehicle simulation has been widely utilized for the vehicle performance evaluation, nonlinearities associated with the air suspension behavior are vastly simplified and the air mass flows of the leveling valve (LV) and differential pressure valve (DPV) are neglected in many cases. It is, however, known that changes in the air spring pressure caused by the LV and DPV make a non-negligible impact on the vertical wheel load variation and the derailment safety in small radius curved tracks. Therefore, this paper presents a numerical procedure for the analysis of the coupled vehicle and air suspension system behavior, considering nonlinearities associated with LV and DPV flow characteristics. To enable quick and accurate prediction of the history-dependent LV-induced wheel load unbalance and its impact on the derailment safety, quasi-static vehicle motion solvers for the fully coupled vehicle and air spring system flow equations are developed. Several numerical examples are presented to demonstrate the simulation capabilities developed in this study and numerical results are validated against the test data.
Modeling Nonlinear Oscillators via Variable-Order Fractional Operators
Authors: Patnaik Sansit , Semperlotti Fabio
Published: November 2019

Fractional derivatives and integrals are intrinsically multiscale operators that can act on both space and time dependent variables. Contrarily to their integer-order counterpart, fractional operators can have either fixed or variable order (VO) where, in the latter case, the order can also be function of either independent or state variables. When using VO differential governing equations to describe the response of dynamical systems, the order can evolve as a function of the response itself therefore allowing a natural and seamless transition between largely dissimilar dynamics (e.g. linear, nonlinear, and even contact problems). Such an intriguing characteristic allows defining governing equations for dynamical systems that are evolutionary in nature. In this study, we present the possible application of VO operators to a class of nonlinear lumped parameter models that has great practical relevance in mechanics and dynamics. Specific examples include hysteresis and contact problems for discrete oscillators. Within this context, we present a methodology to define VO operators capable of capturing such complex physical phenomena. Despite using simplified lumped parameters nonlinear models to present the application of VO operators to mechanics and dynamics, we provide a more qualitative discussion of the possible applications of this mathematical tool in the broader context of continuous multiscale systems.
On-Line Programming of Robot Skills
Authors: Heikkilä Tapio , Saukkoriipi Janne , Ahola Jari M. , Seppälä Tuomas
Published: November 2019

Robot skills provide a way to model and reuse sensor and robot technologies in effective ways. Skills can integrate and synchronize robot actions and sensor data in a consistent way and provide a framework for configurable robot systems, enabling quick setups of applications. Skills and skill modeling can be used not only for representing the composition of sensor based robot tasks, but also for programming on-line such tasks. In this paper we will introduce a skill based approach for representing on-line programming of skill based tasks. We will also give a practical example for modelling and implementing on-line programming of a handling skill relying on use of object localization sensors.
Collaborative Mind-Mapping: A Study of Patterns, Strategies, and Evolution of Maps Created by Peer-Pairs
Authors: Chen Ting-Ju , Mohanty Ronak R. , Hoffmann Rodriguez Miguel A. , Krishnamurthy Vinayak R.
Published: November 2019

We present a study on collaborative mind-mapping to understand how peers collaborate in pairs to create mind-maps, how the maps evolve over time, and how collaboration changes between the peer-pair across multiple maps. Mind-mapping is an important tool that is studied and taught in design practice and research respectively. While widely used as a brainstorming technique, the collaborative aspects of mind-mapping are little understood in comparison to other ideation methods such as concept sketching etc. In addition to presenting creativity ratings on the outcome (i.e. the mind-map), we extensively report on the patterns of collaborative exploration, strategies that emerge from the collaborators, inhibition, and the overall process of map creation. We discuss the implications of these observations on the development of computer-support for mind-mapping.
Feasibility Study of an Aerial Lifting Device Using Aerodynamic Drag for Ascent
Authors: Lin Xuan , Fernandez Gabriel , Ghassemi Sepehr , Hong Dennis W.
Published: November 2019

Flying typically involves thrust or buoyancy in order to climb in altitude while trying to minimize drag. These setups can result in large, energy-exhaustive mechanisms. This paper presents a novel alternative to the traditional approaches of flying by utilizing aerodynamic drag. Drag can be used as an opposing force needed to lift a load off of the ground. The concept is verified through a series of experiments in which a balloon is used to lift a parachute to a desired height, and then an actuator with a load on the ground retracts a rope connected to the parachute. Aerodynamic drag is translated into a lifting force. This cost-effective, energy efficient, and modular method can increase the mobility of robots, delivery systems etc.
A Coarea Formulation for Grid-Based Evaluation of Volume Integrals
Authors: Uchytil Christopher , Storti Duane
Published: November 2019

We present a new method for computing volume integrals based on data sampled on a regular cartesian grid. We treat the case where the domain is defined implicitly by a trivariate inequality f(x,y,z) < 0, and the input data includes sampled values of the defining function f and the integrand. The method employs Federer’s coarea formula to convert the volume integral to an integral over level set values where the integrand is an integral over the level sets. Application of a standard quadrature method produces an approximation of the integral over the continuous range of f in the form of a sum of integrals on level sets corresponding to a discrete set of values of f. The integrals on the discrete collection of level sets are evaluated using the grid-based approach presented by Yurtoglu et al. [1].

We describe how the implementation relates to the implementation described in [1], and we present results for sample problems with known exact results to support a discussion of accuracy and convergence along with a comparison with a traditional Monte Carlo method.
Dimensions of Product Similarity in Design by Analogy: An Exploratory Study
Authors: Gill Amaninder Singh , Tsoka Arnold N. , Sen Chiradeep
Published: November 2019

This paper explores dimensions of similarity in analogy-based design through a user study. Analogy is used in design to help designers use knowledge that exists between and across domains in order to solve design problems at hand. The five dimensions of similarity that were explored in this paper are: function, form, energy flow, material flow, and motion. Fifty student volunteers, majoring in Mechanical Engineering, were given electro-mechanical products that are to be designed, and were asked to select, from a set of options, other products that they considered could be useful references for their task, if those options were offered by a hypothetical design-by-analogy web-service. In their response, they were also asked to identify the dimensions along which they found their preferred reference products to be similar to the design product. It was observed that participants selected products based on similarity along multiple dimensions of analogy. Function-based similarity was the most dominant trait, followed by energy, motion, material, and form. The results from this study will help to design more elaborate studies that will inform the design of computational support algorithms that will aid designers by recommending analogous solutions to help with solution search and ideation.
Multi-Scale Design of Meta-Materials With Offset Periodicity
Authors: Sadiwala Rushabh , Fadel Georges
Published: November 2019

Meta-materials are a class of artificial materials with a wide range of bulk properties that are different from the base material they are made of. The term meta-material in the context of this research refers to a continuous, heterogeneous structure with prescribed elastic properties. Such meta-materials are designed using Topology Optimization (TO). Tools like SIMP interpolation, mesh filtering and continuation methods are used to address the numerical issues with Topology Optimization.

In a previous research [1], by offsetting meta-material layers by a half-width of the Unit Cell, an auxetic honeycomb-like geometry was obtained. This was the first time such a shape was observed as the result of Topology Optimization targeting the effective shear modulus using square Unit Cells. This was obtained while designing the shear beam of a non-pneumatic wheel.

This research studies the design of meta-materials using offsets other than zero or half-widths. The same problem [1] was solved for different values of offset, and the obtained geometries and volume fractions are studied. It is concluded that it may be beneficial for designers to consider offsetting meta-material layers with offsets other than half-width, to design novel, potentially better performing structures.
The Technology/Tactics (TEC/TAC) Plot: Explicit Representation of User Actions in the Product Design Space
Authors: Stapleton Tyler , Owens Trent , Mattson Christopher , Sorensen Carl , Anderson Michael
Published: November 2019

The initial phases of the design process — including interactions with stakeholders, ideation of concept candidates, and the selection of the best candidates — have a large impact on the success of a project as a whole. They also tend to be the most unstructured portion of the project, and are often marginalized by teams who assume they already understand stakeholder needs and the best solution paths to pursue. Design researchers have developed methods shown to increase the creativity and divergent thinking of the design team during these initial phases of design. Nevertheless, these methods often rely on only a vague or amorphous representation of the design space (the set of all possible concepts the design team could feasibly select to meet the objective of the project). In this paper, we introduce a particular design-space structure that can help teams ideate and evaluate their ideation, thus improving the early phases of the design process. The design space presented here is a vector space with a basis of technology (the physical product people will use) and tactics (the procedure for using the product). Also presented are definitions, principles, and sub-theories that facilitate the creation and use of technology-tactics plots to represent the design space. Considering the design space in this structured way, the design team can gain valuable insights that improve the effectiveness of the initial stages of design, and may yield additional benefits to the design process as a whole, if further developed.
A Review of Machine Learning Applications in Additive Manufacturing
Authors: Razvi Sayyeda Saadia , Feng Shaw , Narayanan Anantha , Lee Yung-Tsun Tina , Witherell Paul
Published: November 2019

Variability in product quality continues to pose a major barrier to the widespread application of additive manufacturing (AM) processes in production environment. Towards addressing this barrier, monitoring AM processes and measuring AM materials and parts has become increasingly commonplace, and increasingly precise, making a new wave of AM-related data available. This newfound data provides a valuable resource for gaining new insight to AM processes and decision making. Machine Learning (ML) provides an avenue to gain this insight by 1) learning fundamental knowledge about AM processes and 2) identifying predictive and actionable recommendations to optimize part quality and process design. This report presents a literature review of ML applications in AM. The review identifies areas in the AM lifecycle, including design, process plan, build, post process, and test and validation, that have been researched using ML. Furthermore, this report discusses the benefits of ML for AM, as well as existing hurdles currently limiting applications.
Extending Educational Robot Sensing Capabilities Through Equipping an External Microcontroller
Authors: Qian Binsen , Cheng Harry H.
Published: November 2019

The popularity of the educational robot in K-12 classroom has dramatically increased in the past decades to engage students studying not only Science, Technology, Engineering and Mathematics (STEM), but also 21st-century skills. Most educational robots tend to be as simple as possible such that the lower grades can benefit from the robotics technologies safely. However, such design consideration makes most educational robots with none or minimal sensing capabilities. However, it is very important for senior students to learn more advanced robotics concepts and applications. This paper presents a concept of extending educational robots’ sensing capabilities through quipping an external microcontroller. The paper also demonstrates how the framework can be easily used in sensor-based applications through a line-following example.
Thorough Verification and Validation of CFD Prediction of FPSO Current Load for Confident Applications
Authors: Xu Wei , Huang Zhenjia (Jerry) , Kim Hyunjoe
Published: November 2019

In this paper, a thorough verification of FPSO current load modeling and simulation using CFD was carried out and a modeling practice developed in a joint development project [1] was adopted. The towing test data obtained with thorough quality assurance process were used as benchmark data in the verification work. To have high confidence in the CFD modeling and simulations, both steady simulations with RANS model and unsteady simulations with IDDES model were carried out. For the steady simulations, sensitivity checks were carried out for the domain size, mesh refinement, turbulence models, boundary conditions and Reynolds effect. For unsteady simulations, the wake zone mesh refinement, time step size, number of inner iterations and different RANS model for boundary layers were considered during the sensitivity verification stage. It was found in this study that the transverse load (Fy) and yaw moment (Mz) of the FPSO can be predicted fairly well using RANS model, while the DES model needs to be adopted in order to accurately predict the longitudinal forces (Fx) at certain range of current directions. The wake grid for the DES needs to be fine enough in order to capture the details of vortices and the running time trace needs to be long enough to reduce the sensitivity on the mean current forces.