bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Kinetostatic Modeling of a Cable-Driven Schönflies-Motion Generator
Authors: Sciarra Giuseppe , Rasheed Tahir , Mattioni Valentina , Cardou Philippe , Caro Stephane
Published: November 2022

Cable-Driven Parallel Robots (CDPRs) use cables to move a moving-platform in space offering different advantages, such as high payload, reconfigurability, large translational workspace and high dynamic performances. However, their orientational workspace is usually limited due to cable/cable and cable/moving-platform collisions. In this paper, a novel Schönflies-Motion Generator (SMG) with a large translational workspace and a full rotation of its end-effector about a vertical axis is introduced. The full rotation of the end-effector is obtained using a parallelogram cable loop. It should be noted that the four degrees of freedom motion of the end-effector is controlled by four actuators fixed to the ground thanks to three parallelogram cable loops and a transmission system containing a differential mechanism. The kinetostatic model of the CDPR under design is expressed. The static workspace of the proposed Cable-Driven SMG (CDSMG) with three different cable arrangements is analyzed. Finally, a prototype of the CDSMG is presented and preliminary experimental results are discussed.
Objects of Collaboration: Roles of Objects in Spanning Knowledge Boundaries in a Design Company
Authors: Brubaker Eric R. , Sheppard Sheri D. , Hinds Pamela J. , Yang Maria C.
Published: November 2022

Engineering designers often span knowledge boundaries when developing complex systems but doing so poses challenges because members of different knowledge groups must bridge their language, cognitions, and “thought worlds” to effectively broker, resituate, and make use of each other’s ideas. Objects — ranging from prototypes to kanban boards to value stream maps — are frequently used in cross-functional design practice, but the outcomes associated with such objects appear varied and dependent not only the objects’ characteristics but on how, when, and by whom they are used. This paper describes a two-year inductive ethnographic study within a turbomachinery design company to understand how cross-functional design teams span their knowledge boundaries to advance their designs and design processes. We collected observations of 70 cross-functional meetings and 52 interviews across functional groups during the development of complex turbomachinery products. Our findings include three roles of objects of collaboration: routinizing cross-boundary interaction, translating information across boundaries, and motivating joint negotiation or discovery. We found two prominent outcomes — co-discovery of a design risk, opportunity, or workflow bottleneck and co-design of a joint integrated solution — that appeared to follow from the latter two roles, respectively. These findings are significant because they clarify the roles of objects in cross-boundary design work and suggest ways for designers to more effectively use objects to span knowledge boundaries.
A Curved Compliant Differential Mechanism With Neutral Stability
Authors: Mak Robin , Amoozandeh Nobaveh Ali , Radaelli Giuseppe , Herder Just L.
Published: November 2022

Differential mechanisms are remarkable mechanical elements that are widely utilized in various systems; nevertheless, conventional differential mechanisms are heavy and difficult to use in applications with limited design space. In this paper, a curved lightweight compliant type of differential mechanism is presented. This mechanism acquires its differential characteristic by having a high rotational stiffness when the mechanism is symmetrically actuated on two sides, while having a low rotational stiffness when actuated only on one side. The intrinsic elastic strain energy required for deformation of the compliant differential is compensated for by reintroduction of potential energy to make the mechanism neutrally stable. For the storage of potential energy, two preloaded linear springs were used. The rotational stiffness of the one-sided actuation around the neutral position of the compliant differential mechanism is hypothesized to be adjustable by changing the preload of the springs. The stiffness can be positive, zero, and negative, meaning that the mechanism can have neutral stability and bistability. The hypothesis is investigated using a simulated model in Ansys Parametric Design Language using optimized parameters to achieve the desired stiffness for the mechanism. The simulated model is validated using an experimental setup for both the one-sided and symmetrical actuation stages. The experimental results showed a high correlation with the simulations. The mechanism with optimized dimensions and preload showed neutral stability for a range of 16°. Bistability was found for preloads higher than the aforementioned optimized preload. A linear trend was found between the preload of the springs and the rotational stiffness of the mechanism at θ = 0. Furthermore, an output/input kinematic performance of 0.97 was found for the simulated results and 0.95 for the experimental results.
Influences of Engineering Student Backgrounds and Experiences on Conceptions of Product Design
Authors: Corby Adam , Hoffenson Steven , Pitterson Nicole
Published: November 2022

In undergraduate engineering programs, recent emphasis has been placed on a more holistic, interdisciplinary approach to engineering education. Some programs now teach product design within the context of the market, extending the curriculum to topics outside of scientific labs and computational analysis. This study analyzes survey and concept map data collected from 154 students in a third-year engineering design course. The aim is to evaluate the impacts of student backgrounds and experiences on their mental models of product design. Data were gathered from surveys on student backgrounds and experiences, along with concept maps that were generated by the students on the first day of a product design class. The concept maps were analyzed in a quantitative manner for structural and thematic elements. The findings show that several background attributes influence student conceptions of product design. Academic major appeared to have the largest impact on a variety of variables. Additionally, prior work experience, enrollment in a master’s program, and the presence of an engineering role model at home all showed significant impacts on design conceptions. By analyzing and understanding unique backgrounds of students, educators can adjust their curricula to more effectively teach design concepts to students of various backgrounds and experiences.
Effect of the Impact Coefficient of Restitution on the Nonlinear Dynamics Phenomenon of Flat-Faced Follower With Polydyne Cam Mechanism With Clearance
Authors: Yousuf Louay S.
Published: November 2022

The effect of impact coefficient of restitution on the nonlinear response of the follower is investigated at different follower guides’ clearances, different cam speeds and different followers’ offsets. The impact between the cam and the follower and between the follower and its guides are considered in the presence of coefficient of restitution and follower offset. The chaotic phenomenon of the follower due to the impact coefficient of restitution is detected by using phase-plane diagram. The numerical simulation of the nonlinear response of the follower is simulated using SolidWorks program. The chaotic phenomenon in cam follower system is increased with the increasing of impact coefficient of restitution value in which the potential energy of the follower has been decreased in the presence of follower offset. The chaotic motion of the follower response is occurred due to the increase in cam speeds, follower’s offsets, follower guides’ clearances and impact coefficient of restitution.
Identification of Motor Control Objectives in Human Locomotion via Multi-Objective Inverse Optimal Control
Authors: Tomasi Matilde , Artoni Alessio
Published: November 2022

Predictive simulations of human motion are a precious resource for a deeper understanding of the motor control policies encoded by the central nervous system. They also have profound implications for the design and control of assistive and rehabilitation devices, for ergonomics, as well as for surgical planning. However, the potential of state-of-the-art predictive approaches is not fully realized yet, making it difficult to draw convincing conclusions about the actual optimality principles underlying human walking. In the present study we propose a novel formulation of a bilevel, inverse optimal control strategy based on a full-body three-dimensional neuromusculoskeletal model. In the lower level, prediction of walking is formulated as a principled multi-objective optimal control problem based on a weighted Chebyshev metric, whereas the contributions of candidate control objectives are systematically and efficiently identified in the upper level. Our framework has proved to be effective in determining the contributions of the selected objectives and in reproducing salient features of human locomotion. Nonetheless, some deviations from the experimental kinematic and kinetic trajectories have emerged, suggesting directions for future research. The proposed framework can serve as an inverse optimal control platform for testing multiple optimality criteria, with the ultimate goal of learning the control objectives that best explain observed human motion.
Harnessing Operational Flexibility From Power to Hydrogen in a Grid-Tied Integrated Energy System
Authors: Rahman Jubeyer , Jacob Roshni Anna , Zhang Jie
Published: November 2022

Integrated energy systems (IES) are desirable in the power system due to their self-sufficiency and prompt response during critical operating conditions. In addition to reinforcing the system robustness, they are also capable of providing a number of ancillary services. Over the recent years, clean hydrogen has been explored as a promising solution to help the operation of a low-carbon grid. This work seeks to evaluate the benefits of integrating a hydrogen production facility into an IES infrastructure from the perspective of operation flexibility. Specifically, a grid-connected IES that consists of a small modular reactor (SMR), a wind farm, an electrolyzer that produces hydrogen, a fuel cell that converts hydrogen to electricity, and a hydrogen storage tank, is modeled and studied. The IES components are modeled considering their suitability for performing both power system unit commitment and economic dispatch simulations, and in this study we focus on day-ahead simulations. The proposed IES configuration aims to leverage the low-cost surplus generation (from SMR or wind) to produce hydrogen that could be used in peak load periods or traded in the hydrogen market. The results on the NREL 118-bus system simulation show that the IES could help reduce the total production cost and renewable curtailment in the system operation.
Dispersion Morphing in Highly-Reconfigurable Rotator Lattices
Authors: Fang Lezheng , Leamy Michael J.
Published: November 2022

We investigate wave propagation in in-plane rotator lattices and demonstrate dispersion morphing and extreme acoustoelastic effects using analytical and numerical means. By changing the angle of the rotator arms attaching the elastic linkage between adjacent rotators, we show that the band structure may morph from a positive/negative-group-velocity passband into a flat band across the whole wavenumber space, and then into a negative/positive-group-velocity passband. A similar process can also occur at certain fixed arm angles when the lattice constant changes, which one may interpret as stretching or compressing the structure along the lattice directions, effectively mimicking the acoustoelastic effect. We analytically investigate both processes and provide closed-form expressions for the occurrence of flat bands, which indicates the transition of the passband property. Further, we explore a chiral rotator lattice design where the oscillation equilibrium position for each rotator may shift upon the change of the lattice constant. This design has a unique advantage that the morphed passband maintains approximately the same frequency range such that a signal may stay propagating during the process of dispersion morphing. In the end, we present numerical simulations for three potential applications utilizing the aforementioned findings. In these applications, both static and dynamic lattice stretching are considered, resulting in on-demand bi-directional wave-guiding, refraction bending, and time-modulated amplifying. Numerical simulations document a high-quality agreement with theory and yield promising results that may inspire next-generation reconfigurable metamaterials.
Numerical Identification of Freedom Spaces Using the Canonical Basis
Authors: Archer Nigel , Hopkins Jonathan
Published: November 2022

In this paper, we introduce a complete set of numerical algorithms to find the principal twists of all freedom spaces given an arbitrary set of desired twists without explicitly constructing the reciprocal constraint space. Principal twists, sometimes referred to as the canonical basis, are the set of twists closest to being mutually orthogonal and reciprocal within the twist space. They can be used to categorize and identify freedom spaces by comparing their relative pitches and angles to that of the canonical forms for each space. The identification of freedom spaces (i.e., twist spaces) has been a central problem in screw theory since its conception. Until now, there has been no autonomous computational tool that can identify, locate, and orient a freedom space defined by any set of desired degree-of-freedom motions (i.e., twists). The authors are developing this tool as part of an Add-in for SolidWorks to guide users in designing compliant mechanisms via the freedom and constraint topologies (FACT) synthesis approach. The specific contributions of this paper, which were necessary to create this tool, are the following: (i) existing analytical methods are converted to complete numerical solutions, (ii) existing numerical tools are made more concise and efficient, (iii) new methods are derived to identify principal twists, and (iv) loose definitions within the field of screw theory are fortified.
A Novel Variable Stiffness Compliant Robotic Link Based on Discrete Variable Stiffness Units for Safe Human-Robot Interaction
Authors: Fu Jiaming , Lin Han , Xu Wei , Gan Dongming
Published: November 2022

Variable stiffness manipulators balance the trade-off between manipulation performance needing high stiffness and safe human-robot interaction desiring low stiffness. Variable stiffness compliant links provide a solution to enable this flexible manipulation function in human-robot co-working scenarios. In this paper, we propose a novel variable stiffness link based on discrete variable stiffness units (DSUs). A DSU is a parallel guided beam that can adjust stiffness discretely by changing the cross-sectional area properties of the hollow beam segments. The variable stiffness link (named Tri-DSU) consists of three tandem DSUs to achieve eight stiffness modes and a maximum stiffness change ratio of 31. To optimize the design, stiffness analysis of the DSU and Tri-DSU under various configurations and forces was performed by a derived theoretical model compared with finite element analysis (FEA). The analytical stiffness model is derived using the approach of serially connected beams and superposition combinations. It works not only for thin-walled flexure beams but also for general thick beam models. 3-D printed prototypes were built to verify the feature and performance of the Tri-DSU in comparison with the FEA and analytical model results. It’s demonstrated that our analytical model can accurately predict the stiffnesses of the DSU and Tri-DSU within a certain range of parameters. The developed variable stiffness link method and analytical model are extendable to multiple DSUs with different sizes and parameter configurations to achieve modularization and customization. The advantages of the stiffness change mechanism are rapid actuation, simple structure, and compact layout. These methods and results provide a new conceptual and theoretical basis for the development of new reconfigurable cobot manipulators, variable stiffness structures, and compliant mechanisms.
Iterations in Design and Development Process Illustrated Using Reconfigurable Robot Case Study
Authors: Leong Kristor J. K. , Hayat Abdullah Aamir , Yi Lim , Elara Mohan R. , Karthikeyan Elangovan
Published: November 2022

Iterations in design is ubiquitous to drive constant innovation in the pursuit of excellence in product development, service delivery, systems, and subsystems integration. Within a given time frame of a design process, iteration can occur at different scales, forms, types, etc. Iteration was highlighted recently in the innovation framework using the four ‘D’s design scheme, i.e., Discover, Define, Develop, and Deliver. Iteration studies generally focus on its occurrence, modeling, classification, methods, and impact, among others, in the domain of software development, service providing, aesthetics, and functionality. However, aspects of an iteration involving complex systems like a reconfigurable system become more intriguing because of its overall morphology with changing features and the coupled design of several subsystems. This paper reports on the various factors influencing iteration and are illustrated using a case study of the development of a reconfigurable robotic system named Panthera and its subsystems designed for cleaning and maintenance tasks. The case study of Panthera is reported from its initial ideation phase to the three versions development over a span of three years. Following the journey of the system design of Panthera, it details the timeline, rationale, and insight into the iterative processes and how they are applied to the individual subsystems in consecutive design iterations. With no one solution that fits all approaches to the topic, we aim to highlight and stimulate concepts to aid designers in the design iteration.
Modeling, Simulation and Analysis of a Variable Inertia Reaction Wheel Assisting Device
Authors: Okabe Eduardo P. , Brittes José Luiz P. , Miletto Daniel L.
Published: November 2022

Reaction wheels have been used in controlling the orientation of spacecraft and robots. They are particularly useful when there is not a solid foundation or track to support the motion. Tree pruning close to power lines is a risky activity that can lead to fatal accidents. The pole saw operator usually stays on top of a boom lift platform that is very bouncy and the space is very restricted. Using a reaction wheel to assist the motion of the pole saw can relief the human effort and make the operation faster. To improve the customization of the reaction wheel system a variable inertia rotor can be used, which can be adjusted to best fit the operation. The variable inertia is obtained by radially displacing the rotor segments thus increasing its moment of inertia. These segments are attached to the rotor hub through a set of springs and dampers. The rotor hub is driven by a reduction transmission attached to a brushless motor. This variable inertia reaction wheel system was modeled and simulated in two situations: kickback reaction and tree pruning. Although the system is composed by a single reaction wheel, the results showed that the system can help in both situations, reducing the effort up to 34%.
Examining a Trajectory of Complex System Design Processes: Airport Eco-System Case Studies by Novice Student Teams
Authors: Kim Euiyoung , Rao Vivek , Bluemink Bart , Klitsie Barend , Santema Sicco
Published: November 2022

As the aviation industry has become more complex and uncertain, we need to teach aviation topics with different pedagogical approaches: making the educational setting interdisciplinary and more design- and user-driven. We developed a design curriculum to address emerging complexity around air travel journeys and piloted the curriculum at a major research university in the Netherlands. Novice students in engineering, design, and social science programs in the Future of Airport minor on campus engaged in a quarter-long design course centered on the seamless air travel experience. The course aims to teach students how to approach the complexity of an airport and the stakeholders involved and design for people in transit. Data were collected from the results of work in document format (project progress reports and final deliverables) from thirty-five student teams who collaborated with aviation industry sponsors to develop solutions to address complex system-level industry design challenges. We classified the detailed project brief and outcomes by different innovation levels (product, service, system, or socio-technical), and examined the design methods implemented by each team over the design process. Our discussion is divided into (D1) trajectory of levels of innovation traveled during the project execution, (D2) descriptive reflection on overall selecting design methods, (D3) design method selection dynamics over design phases in complex problem domains, and (D4) challenges of offering a design approach to novice engineering students, drawn from the reflection by course coordinators and coaches on the course structure and contents.
A Neutrally Stable Quasi-Compliant Spherical Joint With a Remote Center of Rotation
Authors: Hogervorst Dion , Radaelli Giuseppe , Herder Just
Published: November 2022

This paper presents the design of a compliant spherical joint which is neutrally stable in two DoF and has a remote center of rotation. Such a joint can be used, for example, as an exoskeleton’s shoulder joint. The foundation of this paper lies in previous work that has succeeded in designing a compliant spherical joint with a remote center of rotation, but without neutral stability. The existing joint is simulated and its energy properties are analysed. Thereafter it is adapted and optimized for an axi-symmetrical energy field. A spring is introduced to the joint and optimized such that the combined energy field of both spring and joint, is neutrally stable. Experimental verification of the simulation was achieved with a prototype for which a moment reduction of 83.69% was achieved through the addition of the spring.
A Driving Simulator for UN157 Homologation Activities
Authors: Gobbi Massimiliano , Mastinu Gianpiero , Melzi Stefano , Previati Giorgio , Ronconi Luca , Sabbioni Edoardo
Published: November 2022

UN157 Regulation is devoted to the homologation of SAE Level 3 automated vehicles. The research and development activities related with the Regulation may require an extensive usage of driving simulators. Developing a sickness-free driving simulator is crucial for extensive tests to be performed with ordinary drivers.

The paper presents the technical features of the new driving simulator of the Politecnico di Milano. A number of biometric set of signals is recorded, namely, forces and moments at each single hand at the steering wheel, heart rate variability, skin resistance potential, eye movements. A matching of the objective monitoring of the driver is compared with the subjective psychological status. An initial population of 30 subjects has been investigated.

The new driving simulator has shown a good acceptance by ordinary drivers. Both objective and psychologic subjective assessment agree to state that the new driving simulator may be used to test ordinary driver behavior in a motorway scenario.
Modeling of the Weave and Wobble Eigenmodes of Motorcycles Using Flexible Multibody Simulation
Authors: Passigato Francesco , Gordner Achim , Diermeyer Frank
Published: November 2022

Weave and wobble are well known eigenmodes of motorcycles and have been studied by several authors because of their importance to the overall stability and safety of motorcycles. Studies have highlighted the importance of structural flexibility on these eigenmodes. A common approach in multibody simulationfor modeling the flexibility is the lumped stiffness method. It is advantageous for its limited modeling effort and its small impact on computational time. However, it was never demonstrated if this approach leads to sufficient accuracy when simulating the weave and wobble eigenmodes. The present work answers this question by modeling the structural components of a motorcycle with the flexible multibody approach. The most relevant components for the stability of weave and wobble are identified. A comparison with the lumped stiffness approach is also proposed. Moreover, some implementation details concerning models with flexible bodies are discussed.
Toward Generating System Architecture and Formal Functional Description in the Architecture Analysis & Design Language (AADL) With Structured Natural Language
Authors: Chauhan Anshumaan , Ganeriwala Parth , Sen Chiradeep , Bhattacharyya Siddhartha
Published: November 2022

Model based engineering has enabled automated analytical reasoning early in the design phase. As a result, inconsistencies and design errors can be captured early in the development lifecycle. But there is still a gap in the natural language-based specifications and its actual implementation. This is because the formal method-based tools utilize mathematical principles and theories of computation that require specific skills, thus reducing the usability of model-based engineering. Natural language is the most widely used method to represent specifications. So, it is intuitive to utilize natural language-based representation to generate system and formal annotations such that it will enable automated architectural analysis with much wider acceptance leading to a much broader impact. In our paper we focus on designing the above-mentioned approach that integrates representation of the specifications in a subset of English language which can then be used to generate system architecture in Architecture Analysis and Design Language along with the generation of functional specifications. We illustrate our approach by validating it with use cases from the aerospace and electromechanical domains.
Crankshaft Decoupling Effects on Fuel Economy in HEV-P0
Authors: Hegde Shailesh , Castellanos Molina Luis M. , Bonfitto Angelo , Galluzzi Renato , Amati Nicola , Tonoli Andrea
Published: November 2022

The increasingly stringent emission regulations have been one of the driving forces to explore more sustainable vehicle powertrains. On the one hand, carmakers are finding alternatives to meet these regulations; on the other hand, they are trying to improve smart features, such as chassis dynamics, passenger comfort, and, ride safety. The P0 architecture in a hybrid electric vehicle is a cost-effective layout due to its easy adaptation to the existing conventional vehicle architecture. In a P0 architecture, fuel consumption and emissions are increased when idling the engine during the stops to fulfill cabin air conditioning with the compressor. Thus, optimal energy management during these events would lead to an improvement in vehicle fuel economy. To this end, this work presents a novel configuration in a hybrid electric vehicle by installing an electromagnetic clutch between the internal combustion engine and the belt drive system. The objective of the study is to quantify the benefits of driving the air conditioning compressor with an electric machine under vehicle idle/stop conditions. It is demonstrated that the proposed solution improves the fuel economy as it shuts down the engine and decouples the engine resisting torque during stops. The results presented are simulated in the Worldwide harmonized Light vehicle Test Procedure homologation driving cycle and US06.
Aerial Robot Design Principles in Creative Idea Generation and Evolution
Authors: Tan Chee How , Hölttä-Otto Katja , Foong Shaohui
Published: November 2022

Design principles have been developed in many application fields to codify and formalize expert knowledge to increase the likelihood of design success. While there are abundant design principles reported, most of them have not been validated. However, many have been shown to result in more creative ideas, creating variety in ideas and stimulating idea generation and producing novel ideas. In this paper, we analyzed the Efficient Design Principles for Innovative Aerial Robot Design and investigated their impact on the originality of the produced concepts. We assessed the concepts generated between groups with the help of design principles for originality, using the Decision Tree for Originality Assessment in Design (DTOAD) and qualitatively the ideas they helped produce. We report the results of how the originality of the ideas produced varied across (1) domain expertise, (2) problem novelty and (3) idea evolution. The results reveal that the average originality score is statistically significant for a more novel problem, and the originality is always higher for the evolved ideas. Additionally, the results showed no statistically significant differences in the quantity and originality of the ideas between domain expertise for case problems of different novelty. These results support our understanding of the perceived usefulness of design principles for idea generation in aerial robotics design.
Modular Design, Fabrication, and Experimental Exploration of Phononic Chains Incorporating Interchangeable, Nonlinear Unit Cells
Authors: Mork Nehemiah , Fronk Matthew , Leamy Michael J.
Published: November 2022

We present a modular framework for the streamlined design, fabrication, and experimental exploration of phononic chains composed of interchangeable unit cells. Increased interest in periodic media motivates experimental set-ups for exploring re-configurable lattice designs with variable couplings. We employ additive manufacturing as a means to rapidly assemble lattices interfaced by unit cells in a reconfigurable and modular manner. Additive manufacturing produces lightweight spring-like structures while boasting batch printing capabilities. Batch printing reduces production time and increases uniformity in the lattice by reducing the number of joints. The framework reported herein allows for either linear or nonlinear unit cells to be inserted at interface locations. We discuss two example nonlinear unit cells and explore their effects on wave transmission through an otherwise uniform monatomic lattice. One nonlinear cell blocks low amplitude wave packets but transmits high amplitude signals, whereas the second nonlinear cell yields the opposite effect. These cells may inspire devices such as noise filters and limiters based on signal amplitude. The modular framework also enables serial combinations of lattices and cell types that individually integrate frequency filtering, amplitude filtering, and directional control. By combining unit cells with different filtering effects, it is possible to produce combination filters with multifunctional capability — e.g., simultaneous frequency and amplitude filtering.
Deployable Space-Filling Mechanisms: Asymmetric Zipper-Coupled Tubes and Smooth Sheet Attachments
Authors: Webb Dylan C. , Reynolds Elissa , Halverson Denise M. , Howell Larry L.
Published: November 2022

Zipper-coupled tubes constructed from Miura-ori cells are a unique structure consisting of two tubes which, when coupled in a zipper fashion, resist compression in the normal direction. A wider application of zipper-coupled tubes, however, is precluded by their angular form and symmetry. We demonstrate the construction of asymmetric zipper-coupled tubes based on an asymmetric degree-four vertex, along with a smooth sheet attachment that is flat when the asymmetric zipper-coupled tubes are fully deployed. Furthermore, we provide a mathematical model of the motion of the resulting mechanism, thereby demonstrating the rigid-foldability of the entire mechanism.
Comparison of the Hysteresis Response of Super-Coiled Polymer (SCP) Actuators
Authors: Henry Josh H. P. , Bridge Jacqueline
Published: November 2022

In recent years, Super-Coiled Polymer (SCP) actuators have been investigated as a potential high yield and minimal cost alternative to bulky, power hungry and expensive conventional actuators. A major challenge however, has been finding appropriate general and industry uses for these actuators due to their nonlinear hysteretic response. This paper seeks to compare the hysteretic response for SCP actuators based on different thread weights and sizes and thus suggest possible directions for their use.

The actuators were produced through coiling and heat treatment actuated via Arduino code and a microcontroller circuit. The hysteresis properties were obtained experimentally by supplying a controlled voltage to the system. The response was recorded via a camera and was then processed using MATLAB; the resulting displacement and strain were used to observe the hysteretic characteristics.

These characteristics were used as the basis for recommending different applications for these SCP actuators. The results show single ply supercoiled polymers may be used in sensitive low stress applications, the triple ply and greater number of plies used in high stress applications, and the double ply used in applications that are sensitive but also have moderate stress requirements.

It is recommended that this research into SCP actuators be furthered by developing hysteresis models for compensation, control and exploring their use in robotic systems and tactile mechanisms.
Generalization of Manufacturability Algorithms for Fabricated Assemblies Based on Topology Optimization
Authors: Ramnath Satchit , Shah Jami J. , Detwiler Duane
Published: November 2022

Topology optimization has been widely used for optimizing designs in the automobile industry. The primary goal of topology optimization in automotive body structures is to reduce the vehicle weight while continuing to meet strength and stiffness requirements for different type of loading cases. In designing an automotive component, the presence of styling surfaces drive the post-processing of the optimized results into manufacturable designs. However, in a more generalized case where there is a lack of such a reference model, the cleaning up, and manufacturing of, an optimized design may become challenging. Additionally, the applicability of manufacturing constraints to the topology domain may not always be possible. The only possible manufacturing constraints, in such a case, have to be applied to the whole domain instead of individual components. This paper focuses on development of a set of methods that automate the process of generating a design boundary that would assist in providing constraints to designers when converting the optimized design into a manufacturable one. Additionally, the design boundary can be processed further to divide the design into regions based on hollow or non-hollow components allowing for manufacturing the final design using multiple manufacturing processes. The methods have been described using a triangular rotor as an example.
Data-Driven Modeling of a Pneumatic Yoshimura-Origami Structure With Tunable Dynamics
Authors: Zhang Qiwei , Fang Hongbin , Xu Jian , Li Suyi
Published: November 2022

Origami has been widely used in designing tunable metamaterial due to its folding-induced shape reconfigurability and changeable mechanical properties. However, there is still a lack in achieving tunability via active means, and the tunability still remains in a static domain. Thus, the aim of this research is to solve these two problems. By combining the six-layers Yoshimura-ori with the pneumatic bladder together, a pneumatic Yoshimura-ori (PYO) cell is obtained. Noting that the Yoshimura-ori is coupled with the pneumatic bladder, and the physical parameters of the PYO cell are hard to obtain. Hence, a data-driven method which composed of the forward subset selection and the weighted least square (WLS) is carried out to establish the dynamic model. The whole structure is represented as a nonlinear spring-damper element. Based on the dynamic experiment data, the terms of the model could be determined through the forward subset selection. Then, we could use the WLS to identify the corresponding coefficients. Through numerical simulations, the proposed model could exhibit the frequency spectrum characteristic of the prototype effectively. The results of this paper could provide useful guidelines for the development of intelligent origami structures/metamaterials with excellent tunability, and meanwhile, extend the current investigation level from tunable quasi-static to tunable dynamics.
Data Fusion as a Latent Space Learning Problem
Authors: Eweis-Labolle Jonathan Tammer , Oune Nicholas , Bostanabad Ramin
Published: November 2022

Multi-fidelity modeling and calibration are two data fusion tasks that ubiquitously arise in engineering design. In this paper, we introduce a novel approach based on latent-map Gaussian processes (LMGPs) that enables efficient and accurate data fusion. In our approach, we convert data fusion into a latent space learning problem where the relations among different data sources are automatically learned purely based on the data. This conversion endows our approach with attractive advantages such as increased accuracy, reduced costs, and flexibility to jointly fuse any number of data sources. Additionally, the learned latent space in our approach compactly visualizes the correlations between data sources which allows designers and engineers to detect model form errors or determine the optimum strategy for high-fidelity emulation by only fusing correlated or sufficiently accurate data sources. We also develop a new correlation function that enables LMGPs to estimate calibration parameters with high accuracy and consistency even in the presence of unbalanced and noisy datasets. The implementation and use of our approach are considerably simpler and less prone to numerical issues compared to existing data fusion technologies. We demonstrate the benefits of LMGP-based data fusion on a wide range of analytic examples. by comparing its performance against existing technologies.
Empirical Characterization of Lattice, Spring, and Non-Assembly Mechanisms Fabricated With Nylon Polymer Powder Bed Fusion
Authors: Khatri Nava Raj , Smith Johnathan A. , Egan Paul F.
Published: November 2022

Emerging additive manufacturing technologies are enabling the design of engineered parts with complex geometries and mechanical capabilities. Polymer powder bed fusion (PBF) printing is a promising process that is becoming more economically accessible while providing capabilities for printing non-assembly mechanisms. These processes could enable the automated design of complex personalized biomedical designs, such as prosthetics with integrated lattices, springs, and joints. However, manufacturing constraints and mechanical capabilities of these 3D printed designs requires further investigation to determine their feasibility and capabilities. Here, we conduct dimensional characterization and mechanical testing of Nylon 11 printed parts. Minimum fabrication constraints were measured to determine the smallest beam size as approximately 0.7 mm with a minimum gap size between beams of 0.35 mm. Mechanical testing demonstrated low anisotropy of parts in compression/tension which led to the testing of mechanical lattices with approximate elastic moduli of 25 MPa to 55 MPa. Helical springs worked in compression with a stiffness of approximately 0.2 N/mm to 16.8 N/mm for 3 mm to 7 mm wire diameters. Minimum printable gap sizes were used to inform the fabrication of a fully functional finger prosthetic with joints working directly after print post-processing, with no assembly required. Overall, these are foundational steps in demonstrating design rules and constraints for automating customized designs from polymer powder bed fusion printing, which offers unique capabilities for diverse and mechanically complex engineering applications.
Reliability-Based Optimization of Offshore Salt Caverns for CO2 Abatement
Authors: Zheng Zhuoyuan , Xu Yanwen , Hamdan Bayan , Kohtz Sara , Costa Pedro V. M. , Costa Alvaro M. , Morais Carlos H. B. , Wang Pingfeng
Published: November 2022

In recent years, projects have been proposed to utilize salt caverns as a storage method for supercritical CO2 (s-CO2) and have been carried out around the world, which can effectively reduce the anthropogenic greenhouse gases (GHG) concentration. Careful and rational design of the salt cavern are required to guarantee the structural stability and reliability of the cavern when in service. In this study, physics-based FE models were first developed to simulate the salt cavern construction process and predict the creep deformation of the cavern wall during s-CO2 storage. In addition, Gaussian process (GP) based surrogate models were constructed from FE simulation results to estimate the properties of salt caverns with cheaper calculations. Then, to obtain a reliable and robust design, an RBDO framework was employed with the assistance of an adaptive fidelity enhancement technique to scan through the high-dimensional design space, which provides a swift and efficient search for the optimal conditions while considering the uncertainties in the salt cavern construction process. This research is one of the first to account for uncertainties within the salt cavern design process, and the results show that uncertainties of variables can strongly affect the system reliability and the volume of the salt cavern.
A Three Degree of Freedom Model Approach to Enable a MEMS-Based Neural Computing Unit
Authors: Megdadi Mohammad , Nikfarjam Hamed , Okour Mohammad , Pourkamali Siavash , Alsaleem Fadi
Published: November 2022

With enormous amounts of data being generated every day from countless sensors and sensor networks, the need for intelligent devices to process and make use of this data continues to grow and is only projected to increase. The advent of wearable technologies has exacerbated this problem, and with researchers struggling to process data locally with small power budgets, it is clear a solution is needed. Micro-electromechanical (MEMS)-based innovation will have high impact on these issues. MEMS devices can process computing taskes in the hardware level which consumes almost no power (nW). They are very small in size and do the classification without the need of storing the data which boosts up the power saving. Toward this goal, simulation results for a MEMS network to perform basic neural computing is shown in this paper. The network is made up of a mechanically connected network of three electrostatically controlled microstructures, two of which serve as input layers and the third as output (computing) layers. The mechanical coupling was achieved through stiffnesses connecting the masses of the MEMS. It has been demonstrated that such a device may be programmed to distinguish between a ramp (gradually growing) input signal and a step (abruptly rising) by applying suitable bias voltages to the electrostatic control electrodes. The findings serve as a proof of concept and founding to completing more sophisticated computational tasks using MEMS and opening a new direction for alternative efficient computing technologies compared to current digital computing.
A Novel Mass Sensor Based on Parametrically Excited Mode-Localized Resonators
Authors: Song Jiahao , Zhao Jian , Kacem Najib , Lyu Ming , Sun Rongjian , Liu Pengbo
Published: November 2022

The nonlinear dynamics in micro/nano electromechanical sensor have attracted a myriad of attention of researchers due to its great potential to improve sensors’ performance In this paper, a novel mass sensor exploiting the bifurcation phenomenon in parametrically excited mode-localized resonators is proposed. The mathematical model is established by Euler-Bernoulli theory and solved by the method of multiple scales. Meanwhile, the harmonic balance method combined with asymptotic numerical method is utilized for validation. The dynamics and bifurcation topology of the sensor are investigated and the potential of mass sensing on bifurcation point is explored. Compared to relative shift of frequency, the sensitivity in terms of relative shift of amplitude ratio can be enhanced by 4 orders of magnitude. Finally, the effects of coupling voltage are studied which shows that the sensitivity can be further improve with the decrease of coupling voltage above the mode aliasing.
Coupled Integral Sliding Mode Control for Bidirectional Automated Platoon With an Exponential Spacing Policy and Uncertainty Approximation
Authors: Negash Natnael M. , Yang James
Published: November 2022

This study developed an integral coupled sliding mode control (ICSMC) for an automated platoon with exponential spacing policy (ESP) and bidirectional information flow topology. A highly nonlinear and unknown third-order vehicle model was used to represent the actual driving scenario. An adaptive interval type-2 fuzzy logic system (IT2FLS) was applied to support the main controller to approximate the unknown resistance term.To enhance the performance and effectiveness of the IT2FLS, an effective Nie-Tan type reducer was employed. The overall system’s stability was performed based on the Lyapunov stability theory. To demonstrate the performance of the proposed method, a comparison between other control strategies was also made. The implementation of the controller for both nonlinear and linear systems was proven to be efficient and robust.
On the Modelling Bases of In-Motion Dynamic Characterization of Flexible Structures Subject to Friction and Position Control Delay
Authors: Iklódi Zsolt , Beudaert Xavier , Dombovari Zoltan
Published: November 2022

This article presents a characterisation technique of in-motion machine dynamics based on the principles of numerical continuation. A linear two degree of freedom mechanical model is considered, representing e.g. a flexible moving column of a machine tool, and is subjected to a non-smooth friction and a delayed feedback drive control force, resulting in a model governed by a system of piecewise-smooth delay differential equations. By applying harmonic forcing to the system, periodic solutions can be found, through the continuation of which, an accurate vibratory characterisation of in-motion machine dynamics can be acquired. In the continuation routine, spectral collocation techniques were employed to formulate the discretized boundary value problem of piecewise-smooth periodic orbits, and the pseudo-arclength method was implemented. Special care was attributed to the detection of grazing and sliding bifurcations, and the continuation routine was also extended to allow continuation of these critical points.