bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Robotics Expertise on Iterative Robot Design Decisions and Vulnerability to Design Fixation
Authors: Wilson Cristina G. , Brown Kallahan , Sung Cynthia
Published: November 2023

Robot design is a complex cognitive activity that requires the designer to iteratively navigate multiple engineering disciplines and the relations between them. In this paper, we explore how people approach robot design and how trends in design strategy vary with the level of expertise of the designer. Using our interactive Build-a-Bot software tool, we recruited 39 participants from the 2022 IEEE International Conference on Robotics and Automation. These participants varied in age from 19 to 56 years, and had between 0 and 17 years of robotics experience. We tracked the participants’ design decisions over the course of a 15 min. task of designing a ground robot to cross an uneven environment. Our results showed that participants engaged in iterative testing and modification of their designs, but unlike previous studies, there was no statistically significant effect of participant’s expertise on the frequency of iterations. We additionally found that, across levels of expertise, participants were vulnerable to design fixation, in which they latched onto an initial design concept and insufficiently adjusted the design, even when confronted with difficulties developing the concept into a satisfactory solution. The results raise interesting questions for how future engineers can avoid fixation and how design tools can assist in both efficient assessment and optimization of design workflow for complex design tasks.
Design Factors for the Dimensional Synthesis of Cylindrical Developable Mechanisms
Authors: Vennard Henry , Greenwood Jacob , Butler Jared
Published: November 2023

Developable mechanisms provide unparalleled compactness and deployability. This paper explores the kinematic behavior of developable mechanisms that conform to regular cylindrical surfaces. Equations that define these mechanisms within mechanism synthesis are provided and compared with path and motion synthesis tasks for traditional four-bar mechanisms. The design implications, limitations, and opportunities associated with regular cylindrical developable mechanisms are discussed through the lens of both an analytical and graphical method.
Complete Solutions for the Approximate Synthesis of Spherical Four-Bar Function Generators
Authors: O’Connor Sam , Plecnik Mark , Baskar Aravind , Joo James
Published: November 2023

Kinematic synthesis to meet an approximate motion specification naturally forms a constrained optimization problem. In this work, we conduct global design searches by direct computation of all critical points through stationarity conditions. The idea is not new, but performed at scale is only possible through modern polynomial homotopy continuation solvers. Such a complete computation finds all minima, including the global, serving as a powerful design exploration technique. We form equality constrained objective functions that pertain to the synthesis of spherical four-bar linkages for approximate function generation. For each problem considered, Lagrangian stationarity conditions set up a square system of polynomials. We consider the most general case where all mechanism dimensions may vary, and a more specific case that enables the placement of ground pivots. The former optimization problem is shown to permit an estimated maximum of 268 sets of critical points, and the latter permits 61 sets. Critical points are classified as saddles or minima through a post-process eigenanalysis of the projected Hessian. Approximate motion is specified as discretized points from a desired input-output angle function. The coefficients of the stationarity polynomials can be expressed as summations of symmetric matrices indexed by the discretization points. We take the sums themselves to parameterize these polynomials rather than constituent terms (the discrete data). In this way, the algebraic structure of the synthesis equations remains invariant to the number of discretization points chosen. The results of our computational work were used to design a mechanism that coordinates the unfolding of wings for a deployable aircraft.
Concurrent Probabilistic Control Co-Design and Layout Optimization of Wave Energy Converter Farms Using Surrogate Modeling
Authors: Azad Saeed , Herber Daniel R.
Published: November 2023

Wave energy converters (WECs) are a promising candidate for meeting the increasing energy demands of today’s society. It is known that the sizing and power take-off (PTO) control of WEC devices have a major impact on their performance. In addition, to improve power generation, WECs must be optimally deployed within a farm. While such individual aspects have been investigated for various WECs, potential improvements may be attained by leveraging an integrated, system-level design approach that considers all of these aspects. However, the computational complexity of estimating the hydrodynamic interaction effects significantly increases for large numbers of WECs. In this article, we undertake this challenge by developing data-driven surrogate models using artificial neural networks and the principles of many-body expansion. The effectiveness of this approach is demonstrated by solving a concurrent plant (i.e., sizing), control (i.e., PTO parameters), and layout optimization of heaving cylinder WEC devices. WEC dynamics were modeled in the frequency domain, subject to probabilistic incident waves with farms of 3, 5, 7, and 10 WECs. The results indicate promising directions toward a practical framework for array design investigations with more tractable computational demands.
Roll Center and Centrodes of an Eight-Bar Suspension System
Authors: Lanni Chiara , Figliolini Giorgio , Tomassi Luciano
Published: November 2023

This paper deals with the roll motion analysis of vehicles which are provided of two double wishbone independent suspension mechanisms on the front side. According to a planar car model and supposing that both front wheels are rotating about their fixed revolute joints, the position analysis of an eight-bar mechanism is formulated, in order to determine the position of the roll center, along with the fixed and moving centrodes.

In particular, all instantaneous centers of rotations have been determined by devoting particular attention to the roll center and to those of each wheel with respect to the vehicle chassis, according to the kinematic characteristics of the double wishbone independent suspension mechanism. Moreover, a suitable mechanism with 18 members and 1 d.o.f. is proposed to generate mechanically or by using any CAD-software, both centrodes, according to the direct and inverse planar motion of the chassis with respect to the ground and vice versa. Finally, a first curvature analysis is carried out by using the Euler-Savary equation and the inflection circle, in order to determine the center of curvature of the mass center trajectory for the chassis roll motion. The proposed formulation has been implemented in a Matlab program and several examples allowed its validation in different mechanism configurations.
On the Effects of Inertia Force on the Actual Motion of a Special-Case Grashof Linkage at its Singular Points
Authors: Xie Jin , Liu Zhaohui
Published: November 2023

A special-case Grashof linkage has two singular point at which the linkage may changes from parallelogram form into antiparallelogram form or vice versa. Whereas, at the singular points, the linkage is underactuated and its analysis of dynamics is complicated issue because that the actual motion is dependent upon not only the usual forces but also the inertial forces. Based on Gauss’s principle in which the inertial forces are expressed as a scalar quantity, known as acceleration energy, a method to predict the actual motion of the special-case Grashof linkage is proposed in this paper. The method models the issue into an unconstrained optimization. With the outcomes of optimization, the actual form the linkage taking can be determined by the signs of angular velocities of the two links pivoted to frame. The effectiveness of the method is demonstrated by numerical examples.
An Experimental Study on the Accuracy of Cumulative Damage Models in Gear Tooth Bending Fatigue
Authors: Anichowski Gabriel , Damm Riley , Kahraman Ahmet , Hong Isaac
Published: November 2023

Tooth bending fatigue failure is a primary design concern for gear designers in power transmission applications. Fracture of a gear tooth in operation results in overload conditions to adjacent teeth which cascades into potential failure. Total loss of power transmission usually occurs within seconds of the primary failure. While standard constant stress amplitude fatigue evaluations are common to experimentally determine probabilistic stress life (PSN) relationships, they do not directly measure the fatigue lives under complex, non-constant amplitude loading scenarios applied to gears in most applications. Various cumulative damage models exist to estimate fatigue life under duty cycle loading but their accuracy is both material and stress state dependent. Most models are validated under only uniaxial stress states and for limited materials. There is a void of experimental data that would enable the evaluation of the accuracy of cumulative damage models for gear tooth bending fatigue in typical case carburized gear steels. This research study conducts a standard fatigue evaluation along with two sets of dual stress amplitude single tooth bending fatigue tests to empirically determine the effects of multi-stage loading. Various cumulative damage fatigue models are then employed to estimate the fatigue lives of the dual stress amplitude specimens and the accuracy of each model is assessed.
Towards Quantifying Interviews: Comparing Techniques to Evaluate the Quality of Design Interviews
Authors: Grover Micki , Wright Natasha C. , Lauff Carlye A.
Published: November 2023

Exploratory interviewing for front-end design research is a widely used practice, but unstandardized process. There are documented best practices for conducting “good” interviews, and these skills can be used to develop metrics to evaluate interview quality. A standard practice for verifying interview quality would increase confidence in studies that utilize student or novice interviewers, who often have less interviewing experience than expert researchers. Additionally, metrics to evaluate interviews could be used for individualized feedback to help novices improve over time, and feel confident and ready to complete field interviews for design and research projects. In this study, 12 undergraduate students were trained in design ethnography techniques and participated in field interviewing for a design project related to developing a service model for dialysis treatment in End Stage Kidney Disease in Zimbabwe. The quality of the students’ practice interviews from training and from field interviews during the design project were measured using a calculated scoring method that was developed based on interviewing best practices. To test the validity of the scoring method, this study compared the method to two accepted practices for evaluating interview quality: experts and information gained from interviews. The scoring method was found to not have a strong relationship to either accepted practice. Therefore, the metrics and formula used in the calculated scoring method were reexamined in light of the findings from the practice and field interviews to produce recommendations for future iterations.
Protocol Study: Patterns of Designer Behaviors When Describing Engineering Problem Domains Through Concept Maps
Authors: Kochenberger John , Sen Chiradeep
Published: November 2023

This paper presents a pilot protocol study that examines the behavioral patterns in human designers when they describe a problem domain of engineering interest through constructing concept maps. Ten voluntary participants were assigned a choice of three problem domains and asked to construct concept maps for any one of them. The data was encoded into four elements of the map — nodes, edges, node labels, and edge labels. The data generated was encoded using eleven activity codes and four element codes at a one-second interval. In addition, patterns of forming crosslinks, temporal grouping, and clustering of the elements in the map were examined. The results shed light on the relative difficulty of conceiving and naming the concepts, relations, and distant relations between the concepts, and the patterns of information generation across and within element clusters and temporal groups.
Fixed-Time Learning for Optimal Feedback Control
Authors: Kokolakis Nick-Marios T. , Vamvoudakis Kyriakos G. , Haddad Wassim M.
Published: November 2023

In this paper, we introduce the problem of fixed-time optimal stabilization to construct feedback controllers that guarantee closed-loop system fixed-time stability while optimizing a given performance measure. Specifically, fixed-time stability of the closed-loop system is established via a Lyapunov function satisfying a differential inequality while simultaneously serving as a solution to the steady-state Hamilton-Jacobi-Bellman equation ensuring optimality. Given that the Hamilton-Jacobi-Bellman equation is generally difficult to solve, we develop a critic-only reinforcement learning-based algorithm for learning the solution to the steady-state Hamilton-Jacobi-Bellman equation in fixed-time. In particular, a non-Lipschitz experience replay-based learning law utilizing recorded and current data is introduced for updating the critic weights to learn the value function. The non-Lipschitz property of the dynamics gives rise to fixed-time stability, while the experience replay-based approach eliminates the need to satisfy the persistence of excitation condition as long as the recorded data is sufficiently rich. Simulation results demonstrate the efficacy of the proposed approach.
“LEVER” - Low-Cost Electric Vehicle Charging Robot: Development and Testing
Authors: Cochran Bryan , Zaidi Zulfiqar , Bras Bert
Published: November 2023

This article describes the design and development of an autonomous Electric Vehicle (EV) charging system. An autonomous EV charger can extend the effective range of autonomous EVs by enabling them to recharge without human intervention. The motivation behind the development of the system was to reduce costs compared to other autonomous EV chargers. As such, the system was developed using consumer grade IoT hardware instead of commercial robotic systems and controllers. The system employs a decentralized control architecture with Robot Operation System (ROS) as its backbone. This control architecture utilizes a Raspberry Pi single-board computer as the primary controller, a series of Arduino microcontrollers to interface with motion control, and a Nvidia Jetson vision processors to execute the necessary computation to allow the entire system to operate without the need of a dedicated computer or PLC. The control algorithm utilizes vision feedback and compliant mechanisms to compensate for the limited computational capabilities of the individual microcontrollers. The system was developed in a laboratory environment and once the system operated as intended, the system was tested on a production Plug-in Hybrid Electric Vehicle (PHEV). Experiments were conducted to improve the control algorithm accuracy and decrease operating time. Overall, the system demonstrates the feasibility of using low-cost IoT hardware to develop an autonomous EV charging system, reducing the barrier to entry for the widespread adoption of autonomous EVs. The system represents an important step towards the goal of achieving sustainable and efficient transportation and opens up new possibilities for the future of electric vehicles.
Integrated Sustainable Product Design With Warranty and End-of-Use Considerations
Authors: Liu Xinyang , Wang Pingfeng
Published: November 2023

The idea of integrated sustainable product design has been recently proposed to integrate downstream lifecycle performance into the initial product design to better achieve sustainability. Various sustainable product design tools based on life-cycle assessment or quality function deployment have been established while the influence of reliability in the circular practice has not been investigated much. Realizing that product reliability plays a critical role in determining post-design performance, this paper develops a product design optimization model that considers the warranty performance and the effect of end-of-use options. The effect of uncertain operating conditions on product reliability is incorporated into the model. Two optimization goals including the minimization of expected unit lifecycle cost and environmental impact are achieved by the model. Then, the model has been applied to an electric motor design problem to illustrate the benefit of the integrated approach. Results show that the component selection and reliability design will be adjusted when integrating the end-of-use options in the early design phase. Furthermore, lifecycle cost savings and environmental impact reductions can be achieved through the circular usage of used products. Finally, the effects of operating conditions, warranty policy, and take-back price for used products on the design decisions are analyzed to provide insights for product designers.
Model Validation Based on Value-of-Information Theory
Authors: Hazelrigg George A.
Published: November 2023

The modeling and simulation community has devoted considerable attention to the question of model validity. Their work has focused on the concept of “accuracy,” loosely defined as the difference between a model-computed result and a real-world result. This paper makes use of an example case that results in a paradox to illustrate weaknesses in an accuracy-focused approach, and proposes in its stead a value-focused approach based on classical decision theory. Instead of advocating the use of a model based on its accuracy, this work advocates using a model if it adds value to the overall application thus relating validation directly to system performance. The approach fills significant gaps in the current theory, notably providing a clearly defined validity metric and a fundamental rationale for the use of this metric.
Uncertainty Quantification on Mechanical Behavior of Corroded Plate With Statistical Shape Modeling
Authors: Wu Hao , Bansal Parth , Liu Zheng , Li Yumeng , Wang Pingfeng
Published: November 2023

Corrosion is a process of uncertain nature considering the randomness associated with corrosion initiation and growth, therefore estimating the stochastic behavior of a corroded structure therefore quantifying of system performance uncertainties would be very important for a wide range of engineering systems such as the shipment structure to ensure structural safety and reliability. In the presented study, we have focused on estimating uncertainty on plate mechanical behaviors due to the impact of the corrosion, such as the shape and depth. Considering the limitation of small quantity of corroded plate samples, we firstly regenerate simulated images based on the statistical shape modeling method. Secondly, these simulated images are imported into a multiphysics-based corrosion simulation platform to reconstruct the shape of corroded plate and the mechanical behavior of the plate with different severity levels of corrosions can be obtained through finite element analysis. Thirdly, uncertainty quantification study is then conducted to understand the statistical characteristic of stochastic behavior of corroded plates from simulated and origin image data. The case study results showed that the statistical characteristic of mechnical behavior from both source data are similar, and the statistical shape modeling method could be useful in situations where there is insufficient sample data for uncertainty quantification.
Linear Electrostatic Oscillator With Viscous Damping
Authors: Coonley Kip D. , Humber Hammond , Mann Brian P.
Published: November 2023

Experimental analysis of a translating spring-mass system with a constant electrostatic force in the presence of viscous damping is presented. The challenge in this effort has been to develop an analytical model for the electrostatic system and experimentally extract numerical values for viscous damping and the very small electrostatic force. The system has dynamical equations of motion similar to that of a homogeneous spring-mass system with no external force in the presence of viscous damping. The electrostatic parallel plate system includes the addition of a conservative electrostatic potential energy term corresponding to an electrostatic restoring force. The electrostatic force is conservative and opposes the direction of motion when the position of the oscillating mass being acted upon is greater than or less than zero. Another, similar system comparison can be made between the electrostatic one and that of a translating system acted upon by friction alone. However, the frictional force, unlike the electrostatic one presented here, is non-conservative and, also unlike the electrostatic force, opposes the direction of velocity when the oscillating mass being acted upon is greater than or less than zero. From empirical data, parameters of the translating electrostatic system are determined and cross-verified by more than one method. A state-space model is developed using the Lagranian formalism which includes a dissipative viscous damping term. Results are simulated in Matlab numerically. These simulated results are compared to measured data. Applications of the electrostatic force in a translating set-up are discussed and concluded.
Optimal Swing Assistance Using a Hip Exoskeleton: Comparing Simulations With Hardware Implementation
Authors: Echeveste Salvador , Hernandez Hinojosa Ernesto
Published: November 2023

Despite tremendous potential, predictive simulations for exoskeleton control tend to overpromise the performance of assistance on walking. The transition from simulation to hardware faces several hurdles such as difficulty representing human-machine interface, an overreliance on intuition, and a lack of exploration in assistive strategies. This work presents a simulation-to-hardware strategy that creates optimized assistance profiles to implement on a hip exoskeleton to assist leg swinging as an intermediary step to improve control strategies for walking. By simplifying the activity we were able to observe a smaller disconnect between simulation and hardware. In addition, the comparison provided insight on the differences between the effectiveness of assistance on frequency of the activity and type of work.
Neurocognition of New Ideas During Engineering Design
Authors: Walker Emma , Shealy Tripp , Gero John
Published: November 2023

The research presented in this paper investigated the changes that occur in the prefrontal cortex (PFC) when new ideas are introduced during engineering design. Undergraduate and graduate engineering students (n = 25) were outfitted with a functional near-infrared spectroscopy (fNIRS) headband. Students were asked to design a personal entertainment system while thinking aloud. New ideas were timestamped with the fNIRS data across 48 channels grouped into eight regions within the PFC. The data were preprocessed using temporal derivative distribution repair motion correction, finite impulse response bandpass filter, and the modified beer-lambert law to convert optical density into hemoglobin concentration. Baseline neurocognitive activation and physiological noise were removed. The study found a significant decrease in oxygenated hemoglobin in the left dorsolateral prefrontal cortex and a subregion of the left ventrolateral prefrontal cortex when new ideas were introduced during design. This finding begins to provide a neurocognitive signature of what a new idea looks like as it arises in the brain. This could be used to develop tools and techniques to inhibit this brain region or use this insight to predict when designers will experience a new idea based on their neural activation.
A Unified Real-Time Motion Generation Algorithm for Approximate Position Analysis of Planar N-Bar Mechanisms
Authors: Lyu Zhijie , Liao Wei , Purwar Anurag
Published: November 2023

This paper introduces a novel real-time motion simulation algorithm that enables approximate position analysis of planar N-bar linkage mechanisms of arbitrary complexity. The algorithm was designed specifically for implementation in a web-based software platform, although not exclusively, with the aim of facilitating the simulation and design of mechanisms incorporating revolute and prismatic joints, for both students and industry practitioners. To ensure the efficient computation of positions, all geometric and actuation constraints of links in a mechanism were reduced to the same form, enabling the use of a unified approach. A key aspect of the algorithm is the use of a reinterpretation trick to convert all prismatic elements into a combination of links with only revolute joints. This simplification requires only two solvers while providing motion output within a desired degree of error. Furthermore, the proposed algorithm employs a solving path-finding procedure based on mobility analysis to further reduce simulation time. The resulting algorithm offers the ability to simulate serial, parallel, and hybrid mechanisms with any degree-of-freedom. Additionally, the time estimation for the simulation process and the estimation expression of a mechanism’s structural complexity are provided. To demonstrate the practical utility of the proposed method, the algorithm is applied to several mechanisms as examples.
Investigation of Planetary Gear Elastic Vibrations Using a Finite Element/Contact Mechanics Formulation
Authors: Cooley Christopher G. , Hood Adrian A.
Published: November 2023

The characteristics of the elastic vibrations for the individual gears used in planetary arrangements are important for predicting noise emissions, analyzing potential failure modes, and detecting damage. This work uses a finite element/contact mechanics planetary gear model to investigate the time and spectral vibration properties of the sun, planet, and ring in a fixed-ring configuration. Ring gears have periodic material point accelerations over a planet-pass cycle. Their spectrum has low frequency components at multiples of the planet-pass frequency and high frequency components that appear in clusters near each mesh frequency harmonic. Each cluster contains vibrations at the mesh frequency and upper and lower sidebands separated by the planet-pass frequency. Because of the ring’s compliance, the sideband components are meaningfully larger than the mesh frequency component, and noticeable asymmetry occurs in their amplitudes. The vibrations of a material point on the rotating sun is periodic with the planet-pass period relative to the sun. Therefore, the sideband frequencies observed on the sun are completely different with those on the ring. The rotating sun’s spectrum has low frequency components at multiples of the planet-pass frequency relative to the sun. Each of its clusters contains the mesh frequency component with sidebands at multiples of the planet-pass frequency relative to the sun. Material points on rotating planet gears have periodicity and sideband behavior related to the planet frequency relative to the carrier. Their spectral content is thus different from both the stationary ring and rotating sun. The spectral vibration features demonstrated in this work could be used by condition indicators to detect damage on the individual gears used in planetary arrangements.
Unlocking Team Success: The Power of Diversity in Engineering Capstone Teams
Authors: Vivekanandan Gopalakrishnan Divyaa , Parkinson Matthew , Mohammed Susan , Miller Scarlett
Published: November 2023

Increasing diversity in engineering is a key priority due to the underrepresentation of women and the role of interdisciplinary teams on engineering success. In light of this, it is vital that we consider how to create inclusive teaming practices where individuals feel safe voicing their opinion and challenging team assumptions. The purpose of this paper was to examine the effect of team diversity (gender and interdisciplinarity) on perceived psychological safety through a study with 66 capstone engineering students. This study found that perceived psychological safety can be predicted by the individual’s gender and the team’s gender composition. Furthermore, results also show that adding information related to major can significantly improve the prediction of individual psychological safety. Finally, this study also explores other factors that might affect an individual’s psychological safety in a team and identifies coordination to be the most influential variable. Moreover, it was found that different groups of people are likely to experience more of or emphasize more on certain critical considerations (namely composition, communication, coordination, cooperation, conflict, cohesiveness, and creativity) when asked to describe positive or negative team interactions that affected their perceived psychological safety depending on their gender and team major composition. Study results show promise for further investigating the effect of different types of diversity and other factors on the psychological safety of individuals in the team.
Mean Time to Failure Prediction for Complex Systems With Adaptive Surrogate Modeling
Authors: Wu Hao , Xu Yanwen , Liu Zheng , Wang Pingfeng
Published: November 2023

The Mean Time to Failure (MTTF) is a critical metric for assessing the reliability of non-repairable systems, and it plays a significant role in incident management. However, accurately estimating MTTF can be challenging due to the limited availability and quality of historical experimental data on a group of identical parts or systems. To address this challenge, we propose an adaptive surrogate modeling method, which approximate the system’s performance functions with a more computationally efficient model to predict the MTTF during the design stage. In this paper, we develop an adaptive Gaussian process (GP) approach that combines with Monte Carlo simulation (MCS) to predict MTTF. The proposed method initially trains a GP model for the system’s performance function, and then an MTTF surrogate model can be obtained. With a learning function, these models are updated dynamically based on new information as it becomes available. We demonstrate the effectiveness of our method on series system, parallel system, and mixed system with two examples, and the results show that the adaptive surrogate modeling method can accurately predict the MTTF of the system. Our method has the potential to improve the reliability and safety of complex system and reduces the need for costly performance testing.
Modeling and Analysis of a Thin Plate With Multiple Harmonic Excitations for Vibrotactile Touch Display Applications
Authors: Rajkumar Santosh Mohan , Singh Kumar Vikram , Koo Jeong-Hoi , Yang Tae-Heon
Published: November 2023

Touchscreen devices have become increasingly common in our daily lives. Although smaller touchscreen devices provide sufficient user interaction with meaningful tactile feedback, larger touch devices have the potential to offer a range of tactile stimulation. Previous research on large touch surface vibrotactile localization has utilized numerous actuators and traditional rigid boundary conditions. However, the possibility of localized haptic rendering using multi-frequency excitations is not explored for large rectangular touch surfaces. This study focuses on developing a finite element model of a large touch surface along with a limited number of electrostatic vibration actuators placed at different spatial locations and analyzing the vibrotactile response produced by various combinations of actuators with different frequencies and amplitudes. The effect of the number of actuators and their placement for rendering haptic feedback on the touch surface is explored. Statistical analysis is presented using model simulations to find out a suitable way of actuator placement which is otherwise cumbersome when chosen arbitrarily on a practical device. The effect of the mechanical property of the actuators on the haptic rendering is also explored. Finally, the possibility of localized haptic rendering by switching between actuator frequencies and actuation positions on the touch surface is demonstrated.
Exploring the Role of Individual Differences in System Interpretation
Authors: Patel Apurva R. , Murphy Alexander R. , Summers Joshua D. , Sen Chiradeep
Published: November 2023

This paper presents a study that explores whether individual differences of engineering design self-efficacy and Need for Closure relate to cluster formation for a systems clustering design task. A simplified nine-item engineering design self-efficacy measure was used. A fifteen item need for closure instrument was used. Systems thinking, as related to the size of the clusters created to plan for fault detection of consumer products, is tested using through products and three different modeling representations. Participants (147) from two universities completed three clustering activities. Each participant was given three models for three products. The models included representations of component graphs, function graphs, and function structures. No significant differences were found between university, gender, academic classification, or first language for the size of clusters. Further, neither engineering design self-efficacy or need for closure were shown to be correlated to the results of the design activity. A significant limitation of the study was that the products were of similar size and complexity, meaning that the differentiation between the cluster sizes was limited in scope. Additionally, the student participant population was drawn from first year courses at the two universities. Future work is suggested to include additional individual differences, using more advanced participants, and expanding the scope of the products in the testing. The structure of this experiment can serve as the basis for future studies on the influence of individual difference measures on systems thinking and clustering activities.
Design of a Data Fusion and Deep Transfer Learning Test Rig for Roller Bearings Diagnosis and Prognosis
Authors: Sehri Mert , Dumond Patrick , Bouchard Michel
Published: November 2023

Although they are crucial parts of heavy machinery, bearings are also prone to failure; between 50 and 60 percent of rotating machinery failures are caused by bearings. Data is gathered for the diagnosis and prognosis of bearing faults to help remedy this. Diagnosis relates to identifying a fault situation using recognized symptoms, whereas prognosis focuses on forecasting how the fault will turn out. To determine the states of machines, machine learning techniques are utilized. Deep learning is a branch of machine learning that focuses on training neural networks with several layers. Traditional (shallow) learning, which uses pre-defined features in data to identify machine conditions, and deep learning, which employs complex data types, are two methods of machine learning. In recent years, data fusion and transfer learning have become interesting and important subfields of deep learning. Transfer learning uses previously trained models as a starting point for new tasks by applying learned knowledge from the previous task on the related new task, whereas data fusion mixes many data types to improve comprehension. In this study, the need for large quantities of data fusion and transfer learning data is used to design a test rig for roller bearing fault identification and prognosis. Historically, academic researchers have concentrated on using the data they have gathered with their test rigs to undertake data analysis, rather than concentrating on the design of the test rig itself. Yet, there is a need for a test rig design that appropriately gathers clean multi-sensor data from a variety of bearing sizes to enhance deep machine learning algorithm research for bearing health diagnosis and prognosis via transfer learning. By offering useful methods that can be utilized to perform machine health diagnosis and prognosis on bearings, this work aims to close the gap between the needs of industry and the research community. This can aid in the early detection of faults, offer time frames for repair or replacement, and prevent catastrophic failures.
A Unified Design Equation to Represent Geometric Constraints of Spatial SS, ES and SE Dyads
Authors: Deng Xueting , Purwar Anurag , Ge Qiaode Jeffrey
Published: November 2023

This paper presents a unified design equation for the type and dimensional synthesis of spatial SS, ES and SE dyads for the motion synthesis problems, where S stands for a spherical and E stands for a planar joint. While there has been a lot of research on dimensional synthesis of planar and spherical mechanisms, little work has been done on the type and dimensional synthesis of spatial mechanisms. In this paper, we show that we can derive a single algebraic equation to represent geometric constraints of each of the SS, ES, and SE spatial dyads. While this design equation represents geometric constraints redundantly, explicit mechanical constraints have to be applied to extract the type and dimensional parameters of dyads during synthesis. A two-step algorithm is used to first algebraically fit the given pose constraints of the moving platform and then constraints are applied to obtain type and dimensions. The algebraic fitting is performed using singular value decomposition and candidate sets of solution vectors are obtained. While these candidate vectors are capable of representing any type of spatial dyads, quadratic constraints are applied to obtain mechanical dyads. This paper is an extension of our previous work on type and dimensional synthesis of planar dyads formed with R (Revolute) and P (Prismatic) joints.
An Efficient Surrogate Modeling Method for Reliability-Based Global Path Planning of Off-Road Autonomous Ground Vehicles
Authors: Yin Jianhua , Hu Zhen , Mourelatos Zissimos P. , Gorsich David , Singh Amandeep , Tau Seth
Published: November 2023

The off-road autonomous ground vehicle operation is challenging because of the complex and highly uncertain working environment they operate in. This brings risks to their mission success. Physics-based global path planning combining physics-informed surrogate modeling with path planning is recently employed to address this issue by ensuring a reliability to complete the mission. However, the current two-stage methods require a relatively high computational cost to obtain the reliability map undermining the practicability for real-life applications. To decrease the computational cost, this study proposes an efficient surrogate modeling framework for physics-based path planning under uncertainty. The proposed method couples adaptive surrogate modeling with path planning sequentially through several iterations of path planning and path verification. Instead of obtaining an accurate reliability map for the whole target area in the two-stage approach, the proposed method only refines the map in the vicinity of the path identified, thereby reducing the computational cost. The final path is determined if the path verification is successful; i.e. the specified mission reliability for the path is met. The presented case study demonstrates that the proposed method can significantly reduce the number of surrogate refinement iterations and reduce the computational cost for physics-based path planning.
High-Fidelity Nonlinear Forced Response Analysis of Aero-Engine Turbine Blades With Root Friction Contact
Authors: Tamer Aykut , Schwingshackl Christoph , Jones Adrian
Published: November 2023

In aero-engines, turbines drive compressors and fans by extracting energy from the combusted hot air. For the next generation ultra-high bypass ratio engines, the turbine blades are among the most critical components due to the harsh operating environments. A turbine blade consists of a streamlined aerofoil and the blade root. The root is designed in such a way that it can be inserted into a similar yet marginally bigger slot on the disk. The most common root designs include dovetail and firtree roots. Under normal operation, the blade root is loaded against the slot in the disc by centrifugal forces due to rotation. During operation, blade vibration can lead to microslip in the roots, which generates additional frictional damping and leads to a nonlinear dynamic response. The complex geometry of the blade and its support require high-fidelity finite element analysis to capture the linear dynamic response accurately and detailed frictional interface models to capture the nonlinear response. Therefore, to predict correct amplitude under dynamic loads, friction should be included together with a detailed blade structural dynamics model. This work presents a framework that can combine detailed finite element models with friction models so that a realistic nonlinear dynamic response of the blade can be obtained at representative amplitudes.
Noodle: Design of a Modular, Configurable Serpentine Robot With Series Elastic Actuators and Modular Segment Panels
Authors: Lay Gordon , Pretty Chris , Holder-Pearson Lui
Published: November 2023

This paper outlines and describes the design of Noodle; a modular, reconfigurable, and low-cost serpentine robot. The design is inspired by the diverse set of gaits exhibited by biological snakes, and seeks to provide a universal solution to achieving all of them. However, organic snakes possess varying microscopic ventral scale structures depending on their habitat and gait, which impacts the frictional forward-transverse anisotropy of the ventral scales. To provide a design that will best perform all serpentine gaits, the design proposes modular ventral panels on the sides of the robot’s segments. This acquires the capacity to configure the robot’s ventral contact surface prior to deployment onto a given substrate, and the ability to select its ventral side by rolling and changing orientation. By modularising the ventral contact surface, access to varying degrees of frictional anisotropy is granted, which provides the benefit of selecting the optimal ventral surface for a given gait and/or substrate. Through the inclusion of Series Elastic Actuators, compliance and torque sensory are achieved. Noodle has been designed to accept two types of Series Elastic Elements (SEE): coil-spring and polyurethane. The design, benefits and shortcomings of each SEE type are investigated. Due to these modes of configurability, Noodle can be either configured or be adapted for a given substrate, and provides a basis for implementing active gait adaptation behaviour.
Effects of Soft Contact on the Base of Support of Legged Systems
Authors: Mummolo Carlotta , Duvert Océane , Torres-Pardo Adriana , Rodriguez-Cianca David , Torricelli Diego , Carbone Giuseppe
Published: November 2023

The main balance mechanism in legged systems is the control of the Center of Pressure (COP) over the Base of Support (BOS). The BOS dimensions are therefore strictly related to the control authority of the COP and are typically associated to foot dimensions. This geometrical BOS dimension is valid for the case of ideal rigid flat foot but does not represent the truly available range for COP control, hence the effective BOS, when a compliant foot-ground contact is modeled. This work presents experimental observations on the maximum COP range (i.e., effective BOS) for a subject perturbing its standing balance on rigid and soft grounds. A legged system with a viscoelastic foot contact is modeled to illustrate how a given foot model impacts the effective BOS and can lead to different prediction on the system’s stability, quantified by existing margin of balance. This work motivates the need for novel methodologies for balance and falling prediction, currently focused on ideal rigid feet, in which the effects of a viscoelastic contact on the control of the COP are considered.
Molecular spectroscopy as a laboratory experiment: Measurement of important parameters of sodium diatomic molecules
Authors: Kashem Md Shakil Bin , Davies Morgan , Pant Lok , Bayram S. Burcin
Published: November 2023

We present an inexpensive sodium molecular spectroscopy experiment for use in an advanced undergraduate laboratory course in physics or chemistry. The molecules were excited predominantly from the ground X1Σg+(v″ = 15) state to the B1Πu(v′ = 6) state using a commercially available 532-nm broadband diode laser. The laser-induced molecular fluorescence was measured using a miniature fiber-coupled spectrometer at a resolution of 0.5 nm. The spectral peak assignments were done by comparing the observed spectrum with the calculated Franck–Condon values. Important molecular constants such as fundamental frequency, anharmonicity, bond strength, and dissociation energy of the ground electronic state were determined by using the Birge–Sponer extrapolation method. The presence of highly visible blue glowing molecules along the green laser beam creates an engaging laboratory experience. Emphasis is placed on students developing their understanding of the molecular structure, practicing molecular spectroscopic techniques, and applying knowledge of light–matter interactions to a physical system.
Supplemental Material: Pervasive Neoarchean melting of subducted sediments generating sanukitoid and associated magmatism in the North China Craton, with implications for the operation of plate tectonics
Authors: Li Jialiang , et al.
Published: November 2023

Figures S1–S6 and Tables S1–S7.
Reducing first appointment delays for electron radiotherapy patients by improving the treatment planning pathway: a quality improvement project
Authors: Gately Louise , Sanders Katie , Proudlove Nathan
Published: November 2023

Clatterbridge Cancer Centre (CCC) is a specialist hospital trust in England with three sites.

Delay to the start of an appointment for radiotherapy, especially the first appointment (a ‘New Start’) is poor, both for operational efficiency and patient experience, causing stress for both patients and staff. Our aim is for the New Start to begin within 30 min of the allotted appointment time. To this end, we established another aim: for ‘Final Checks’ to the radiotherapy plan to be completed at least 30 min prior to the New Start appointment time.

Prior to this quality improvement (QI) project, only 33% of electron-treatment New Start appointments started within the target 30 min (the average delay was 52.4 min) and only 48% of the corresponding Final Checks had been completed by their 30 min prior target.

The treatment pathway for these patients was redesigned, with the aim of 90% of New Start appointments starting within 30 min of the allotted appointment time.

By the end of this QI project, 69.2% of New Start appointments started within 30 min of the appointment time (with average delay reduced to 27.2 min), and 92.3% of Final Checks were completed by their 30 min prior target. We also reduced the number of safety (Datix) incidents due to plan not ready from 10 to 0. A year after the project, we have held most of the time improvements and still have had 0 plan-not-ready Datix.

The largest improvement was achieved by introducing a proxy (without the patient present) ‘day 0’ appointment. This takes place in advance of the New Start appointment to enable earlier planning. Subsequent improvements included: automating previously manual planning calculations, making the care path consistent with other external beam radiotherapy care paths at CCC to reduce staff cognitive load and sharing key performance data with staff.