bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physics Guided Machine Learning Approach to Safe Quasi-Static Impact Situations in Human-Robot Collaboration Following the Power and Force Limiting Method of the ISO/TS 15066 Standard
Authors: Kovinčić Nemanja , Gattringer Hubert , Müller Andreas , Brandstötter Mathias 
Published: November 2023

Abstract
Following the performance and force limitation method of the ISO/TS 15066 standard, human safety is evaluated in a quasi-static impact situation in a human-robot collaboration task. To achieve this, all potentially critical impact situations are first identified and then the corresponding impact forces and pressures are experimentally measured and compared with their limit values specified by ISO/TS 15066. If a collaborative application is evaluated as safe, once something is changed in the collaborative workspace, to obtain certainty again, one has to re-assess the safety properties and to re-measure the corresponding forces and pressures. This measurement-based safety assessment severely limits the flexibility of a collaborative process. In this paper, as a method for overcoming the flexibility problem, a physics guided machine learning ensemble for prediction of peak impact forces, within predefined modification dimensions of the collaborative application, is proposed. The input features for the ensemble are obtained using a simplified mathematical model of an impact between a robot and a human. Based on experimentally measured peak impact forces performed with the Universal Robots UR10e, peak impact forces covering an almost whole range of data distribution of interest defined by modification dimensions are obtained using interpolation. As an example of the presented methodology, a generic pick and place task with two modification dimensions is considered. As the most important application of the presented methodology, a map showing the maximal safe impact velocity for a grid of points in a part of a collaborative workspace of interest is shown.
StickBot: A Methodology for Building Robots and Other Functional Elements From Tree Branches and String
Authors: Carroll Devin , Ang Valerie , Yim Mark 
Published: November 2023

Abstract
There are times when robots or robot parts must be improvised from found materials. These times include disaster recovery scenarios, lunar or martian exploration or in areas that are highly resource constrained such as third world countries. For these situations, found materials can be used to construct new robots or robotic elements such as exo-skeletons or orthoses as well as repair damaged components or structures.
This paper quantifies the use of various fastening techniques for attaching together unstructured members, such as tree branches, with actuators to act as the building blocks for robotic links and joints. We quantify which fastener styles are ideal for fixed joints, or for revolute and spherical joints. The techniques considered range from more traditional methods such as diagonal and square lashings to using nuts and bolts to connect components together. In each area we analyze the pros and cons of the technique employed from a complexity, accuracy, and strength perspective. The techniques are then employed to build arm and wrist orthoses as well as a robotic gripper and walker. The range of motion of the orthoses are analyzed. The branch gripper has comparable performance to a commercially available gripper in terms of size and payload. In each case we discuss the pros and cons of these designs and how they can be improved upon.
Multimodal Sensor Fusion for Real-Time Location-Dependent Defect Detection in Laser-Directed Energy Deposition
Authors: Chen Lequn , Yao Xiling , Feng Wenhe , Chew Youxiang , Moon Seung Ki 
Published: November 2023

Abstract
Real-time defect detection is crucial in laser-directed energy deposition (L-DED) additive manufacturing (AM). Traditional in-situ monitoring approach utilizes a single sensor (i.e., acoustic, visual, or thermal sensor) to capture the complex process dynamic behaviors, which is insufficient for defect detection with high accuracy and robustness. This paper proposes a novel multimodal sensor fusion method for real-time location-dependent defect detection in the robotic L-DED process. The multimodal fusion sources include a microphone sensor capturing the laser-material interaction sound and a visible spectrum CCD camera capturing the coaxial melt pool images. A hybrid convolutional neural network (CNN) is proposed to fuse acoustic and visual data. The key novelty in this study is that the traditional manual feature extraction procedures are no longer required, and the raw melt pool images and acoustic signals are fused directly by the hybrid CNN model, which achieved the highest defect prediction accuracy (98.5 %) without the thermal sensing modality. Moreover, unlike previous region-based quality prediction, the proposed hybrid CNN can detect the onset of defect occurrences. The defect prediction outcomes are synchronized and registered with in-situ acquired robot tool-center-point (TCP) data, which enables localized defect identification. The proposed multimodal sensor fusion method offers a robust solution for in-situ defect detection.
Numerical Analysis of Phase Nonreciprocity in a Linear Spatiotemporally Modulated System
Authors: Wu Jiuda , Yousefzadeh Behrooz 
Published: November 2023

Abstract
Vibration transmissibility in a material with spatiotemporal modulation can be changed by just inverting the direction of transmission. This asymmetric feature of transmission can occur due to nonreciprocity. Various studies have demonstrated nonreciprocity in modulated materials by calculating or measuring the differences in amplitudes of response in opposite transmission directions. However, equal amplitudes do not indicate reciprocity because amplitude difference is blind to phase shift. In this work, we investigate nonreciprocal phase shifts (with equal transmitted amplitudes) in vibration transmission through a discrete one-dimensional periodic material subject to spatiotemporal modulation of grounding stiffness coefficients; the transmitted vibrations along the opposite directions have the same amplitude but undergo different phase shifts. We focus on the effects of the number of degrees of freedom (DoF) and modulation amplitude on vibration transmission nonreciprocity. We use the averaging method to calculate the steady-state response of the modulated system. Reciprocity bias and output norms are calculated to evaluate the degree of nonreciprocity in opposite transmission directions. Phase nonreciprocity is identified in cases where output norms are equal but reciprocity bias is not zero. While the response of the system is quasiperiodic, its envelope is periodic in time. We therefore use the response envelopes to help us identify response regimes that are characterized by nonreciprocal phase shifts. The analysis method based on the envelope of the steady-state response facilitates future parametric studies on phase nonreciprocity in discrete materials with spatiotemporal modulations.
Ceramic Bearing Endurance Within a Transmission
Authors: Riggs Mark R. , Hood Adrian A. , Pomplon William A. , Fetty Jason R. , Milligan Ryan , Zielinski John J. 
Published: November 2023

Abstract
Fully ceramic bearings have been demonstrated to provide a forty to fifty percent reduction in weight over steel bearings. They can also provide improved reliability due to increased corrosion protection. One of the primary challenges to incorporating ceramic bearings is the coefficient of thermal expansion mismatch between the ceramic bearing races and its mating surfaces. The application of a tolerance ring was developed to address these challenges. The tolerance ring was applied between the inner bearing race and the pinion shaft to retain the race and absorb the thermal expansion differences, while maintaining an acceptable fit across the thermal operating range. The application of a ceramic bearing within a transmission was evaluated through a 300-hour endurance experiment. The experiment transmitted shaft speeds and torques through the transmission with a vertical load. The ceramic bearing successfully transmitted torque and speed through the duration of the experiment, and vibration did not increase over time. This experiment gives confidence that fully ceramic bearings may be utilized to improve power density and corrosion resistance. In addition, this experiment also demonstrated the ability of the newly commissioned Vehicle Innovative Powertrain Experimental Research facility at Aberdeen Proving Ground, Maryland to successfully perform experiments with novel technologies incorporated into a transmission.
Design Considerations for 3RRR Parallel Robots With Lightweight, Approximate Static-Balancing
Authors: Del Giudice Giuseppe , Johnston Garrison L. H. , Simaan Nabil 
Published: November 2023

Abstract
Balancing parallel robots throughout their workspace while avoiding the use of balancing masses and respecting design practicality constraints is difficult. Medical robots demand such compact and lightweight designs. This paper considers the difficult task of achieving optimal approximate balancing of a parallel robot throughout a desired task-based dexterous workspace using balancing springs only. While it is possible to achieve perfect balancing in a path, only approximate balancing may be achieved without the addition of balancing masses. Design considerations for optimal robot base placement and the effects of placement of torsional balancing springs are presented. Using a modal representation for the balancing torque requirements, we use recent results on the design of wire-wrapped cam mechanisms to achieve balancing throughout a task-based workspace. A simulation study shows that robot base placement can have a detrimental effect on the attainability of a practical design solution for static balancing. We also show that optimal balancing using torsional springs is best achieved when all springs are at the actuated joints and that the wire-wrapped cam design can significantly improve the performance of static balancing. The methodology presented in this paper provides practical design solutions that yield simple, lightweight and compact designs suitable for medical applications where such traits are paramount.
Mobile Manipulation Platform for Autonomous Indoor Inspections in Low-Clearance Areas
Authors: Pearson Erik , Szenher Paul , Huang Christine , Englot Brendan 
Published: November 2023

Abstract
Mobile manipulators have been used for inspection, maintenance and repair tasks over the years, but there are some key limitations. Stability concerns typically require mobile platforms to be large in order to handle far-reaching manipulators, or for the manipulators to have drastically reduced workspaces to fit onto smaller mobile platforms. Therefore we propose a combination of two widely-used robots, the Clearpath Jackal unmanned ground vehicle and the Kinova Gen3 six degree-of-freedom manipulator. The Jackal has a small footprint and works well in low-clearance indoor environments. Extensive testing of localization, navigation and mapping using LiDAR sensors makes the Jackal a well developed mobile platform suitable for mobile manipulation. The Gen3 has a long reach with reasonable power consumption for manipulation tasks. A wrist camera for RGB-D sensing and a customizable end effector interface makes the Gen3 suitable for a myriad of manipulation tasks. Typically these features would result in an unstable platform, however with a few minor hardware and software modifications, we have produced a stable, high-performance mobile manipulation platform with significant mobility, reach, sensing, and maneuverability for indoor inspection tasks, without degradation of the component robots’ individual capabilities. These assertions were investigated with hardware via semi-autonomous navigation to waypoints in a busy indoor environment, and high-precision self-alignment alongside planar structures for intervention tasks.
Development of a Comprehensive Motorless Walking Assistance and Evaluation of Muscle Activity
Authors: Wu Xiuyuan , Wang Yuntian , Osawa Keisuke , Tanaka Eiichiro 
Published: November 2023

Abstract
Walking disorders are a major challenge for people with neuromuscular or musculoskeletal impairments, resulting in reduced mobility and quality of life. This paper addresses an approach to design a comprehensive mechanical walking assist that facilitates foot flexion and extension for the walking by applying the force at the ankle, while adjusting the walking motion and posture to a healthy pattern. The apparatus uses an offset slider crank mechanism to lift the foot and complete the dorsiflexion, and a four-bar linkage to assist the plantarflexion by using the action-reaction force from the lever kicks against the ground. The forefoot mechanical pressure sensor accommodates triggering to both motions, and the heel sensor acts as auxiliary releasing the lever. The experiments showed that both plantarflexion and dorsiflexion are assisted. The corresponding muscle activity for each motion is reduced, promoting a safer and healthier walking. The apparatus has the potential to improve the mobility and quality of life for who with walking disorders and impairments, and could be applied to other domains where mechanical assistance is required, promising a trend to walking rehabilitation with less cost, providing the reference for experiment configuration and further study.
The Effect of Geometrical Quality on the Stress-State in the Plastic Gear
Authors: Zorko Damijan , Vukašinović Nikola , Černe Borut 
Published: November 2023

Abstract
Gear manufacturing errors affect the load sharing between the meshing gears as also the load distribution along the individual tooth’s width. High quality grades are especially hard to achieve for injection molded plastic gears. On the other hand, plastic materials are much more flexible than metals and the teeth deflect and comply under load, leading to an improved load distribution. Larger deviations lead however to a localized contact area resulting in stress concentration and early failure. This study aims to investigate the effect of gear manufacturing quality on the mechanical state of the plastic gear, and consequently also on the gear-life. An original systematic combination of numerical and experimental methods was employed to study these effects. The deviation of geometrical quality parameters, i.e. lead profile and pitch were found to have a substantial effect on the stress (root and flank) state of the gear. The effect of lead deviation was found to be most pronounced for the quality grades Q10 to Q12, while improving the lead quality from Q10 to Q8 did not exhibit a substantial improvement in the load distribution and the corresponding stress. Same was observed for pitch deviation, where again the most pronounced effect was found when improving the quality grade from Q12 to Q10. Quality factors are proposed which can be considered when conducting the root stress and flank pressure calculations in order to include the effect of uneven load distribution in case of larger geometric deviations.
Development of a Validation Process, Overcoming the Challenges Associated With the Evaluation of Design Indicators
Authors: Mesa-López Ana María , Ruiz-Arenas Santiago 
Published: November 2023

Abstract
Different types of indicators have been developed to measure the value of design in companies. As with any tool developed for research, indicators must be developed according to a scientific approach. One of the important steps in this development is validation. The main validation problem for design indicators lies in the following challenges: Design often involves multiple variables and factors that interact with each other. This can make it difficult to isolate the impact of any one indicator on the overall design. Furthermore, design operates differently in each industry. These issues make benchmarking against standardized metrics problematic. Most existing design metrics are qualitative, subject to interpretation, or closed to the public. It is possible that there is no data collected in the companies to evaluate their performance. To the authors’ knowledge, the literature does not describe a systematic validation process for indicators that present difficulties like those exhibited by design indicators. Therefore, this paper presents a proposal for a validation process for design indicators that can be replicated during the indicator development process, which provides a possible solution to these challenges. Four dimensions are considered: face validity, content validity, criterion validity and construct validity. This research is part of a current project that aims to demonstrate the value that the application of design could bring to companies and provide design managers with the tools to support their decision-making.
Parametric Musculoskeletal Model for Human-Robot Interaction Simulation in Warfield Rescue: A Pilot Study
Authors: Lee Seunghun , Cheng Zhiqing , Yang James 
Published: November 2023

Abstract
A novel physics-based human-robot interaction method is proposed and applied to drag the wounded warfighter in the overhead direction in this study. This method predicts the rescue motion using a full-body skeletal model and forward dynamics in OpenSim. The ground reaction force (GRF) is calculated by the contact models in OpenSim, and external forces are applied to the skeletal model. The predicted motion data and a full-body musculoskeletal model are the input for inverse dynamics and static optimization, and the output is joint torques. The simulation results are validated by a kinematic and a joint torque range verification. The proposed model can analyze the rescue scenarios almost in real time and predicts the potential risk of injuries during rescue motion.
Emerging Methods for 2D and 3D Physics Simulation to Support Early Design Decisions
Authors: Chaisiriroj Pongchalat , Stone Robert B. 
Published: November 2023

Abstract
Current approaches to developing 2D and 3D dynamic simulations can be time-intensive to develop and run early in the design process. Recently, machine learning-driven methods have produced near-real-time predictions of design performance. As these approaches rely on backpropagation methods, designers cannot inspect the meaning of results as they pertain to a single target — for example, object class identification or efficiency estimation. In addition, machine learning does not usually generate 2D and 3D field results. This paper identifies and classifies emerging dynamic field simulation methods and previews a novel method for accurate and efficient dynamic simulation. A literature review of recent peer-reviewed journals and books, as well as an exploration of emerging simulation software, will be presented in this paper. A grounded theory approach will be used to extract and classify key concepts. Preliminary examples of interest include cellular automata, decision trees, consensus or crowd-based methods, and hybrid machine learning methods. This study is intended to provide engineers with a better understanding of the emerging capabilities of state-of-the-art simulations in industries parallel and orthogonal to mechanical engineering theory, including gaming, film, and architecture. The work examines a multi-physics challenge in designing electric propulsion systems for spacecraft as dynamic field models for this design space are computationally intensive to produce.
Lab-to-Market Design of an Electrodialysis-Based Home-Scale Water Desalination System
Authors: Floryan Marie , Bowers Quinn , Sternberg Zachary , Gembali Sahas , Goyal Akshita , Bessette Jonathan , Honarparvar Soraya , Winter Amos 
Published: November 2023

Abstract
Water scarcity is increasingly becoming a problem in India, so much so that a recently proposed piece of legislation would mandate home-scale water desalination systems to have a 60% recovery ratio [1], significantly higher than existing systems. We developed an electrodialysis-based home-scale desalination system for obtaining drinking water that will meet and surpass this new proposed recovery ratio. This project builds heavily on previous and current work by the MIT Global Engineering and Research (GEAR) Lab and was conducted with Eureka Forbes Limited (EFL), a major stakeholder in India’s home-scale desalination industry. Two critical design modules within the desalinator are explored — the system integration and fluid reversal mechanism and the electrodialysis stack end cap analysis. We developed a model framework that will output the validity of end cap designs based on established design requirements, designed fluid reversal mechanisms for distinct markets, and fabricated a prototype desalination cabinet that fits within the EFL’s design constraints. We also discuss the details of our collaboration with both academic and industrial partners, extract specific lessons learned about the lab-to-market design process, and discuss some of the specific challenges faced by a design group in our circumstances and the ways we resolved them.
Dynamic Characterizations of O- and X-Carbon Nanotube Reinforced Rings
Authors: Li Hongjie , Deng Yan , Fan Mu , Wang Dan , Tzou Hornsen 
Published: November 2023

Abstract
Carbon nanotube (CNT) reinforced materials exhibit great potential applications because their properties can be tailored by changing the distribution type. Ring structure has been widely used in aerospace, architecture and other fields. This study focuses on the dynamic characterizations of O- and X-CNT reinforced rings under two oscillation conditions. Different distribution types of CNTs, namely, X-distribution type (X), uniform distribution type (UD), and O-distribution type (O), are considered. The influence of embedded CNTs on the mechanical properties of the polypropylene ring is analyzed. To reflect the dynamic characteristics, both the membrane force induced component and bending moment induced component, i.e., transverse and circumferential actions, are studied respectively. The results suggest: (a) the CNTs can improve the mechanical properties of the ring; (b) for the transverse oscillation, the bending behavior of the X-distribution type is larger than that of the membrane behavior, resulting in the largest component induced by the bending moment; and (c) the O-distribution type has a great influence on the membrane behavior, and this component should be the largest in the circumferential oscillation where the membrane force induced component dominates. However, because the volume fraction of CNTs in the three distribution types does not change, the deformation of CNT reinforced ring is uniform.