bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sliding Mode Control of a Quad-Copter for Autonomous Trajectory Tracking
Authors: Wood Daniel , Selekwa Majura F. 
Published: February 2023

Abstract
Unmanned air vehicles or drones have become ubiquitous in our daily lives; they are deployed in performing many tasks from dangerous military missions to simple recreation activities. One air vehicle that has become very popular is the quad-copter driven by four vertical and parallel propellers. Today quad-copters are deployed in many video recording and remote monitoring almost everywhere in the world. One area of interest for quad-copters has been in farming operations; these vehicles are used in farming operations for not only aerial monitoring of soil nitrogen levels but many other farm monitoring operations. One common aspect of most quad-copters is that they are teleoperated by the user, i.e., most of them are not yet fully autonomous. There must be a remote pilot who is connected to the quad-copter by a video link so that he/she can control the maneuver of the vehicle along the intended path. This paper intends to show that a quad-copter can be programmed to run autonomously along a predetermined trajectory by using sliding mode control strategy. Since trajectories in most farms are clearly well known in advance, then they can be programmed into the controller for the quad-copter to autonomously track. The design process involves using the intended trajectory to define the 3-D sliding surface and then letting the quad-copter controller switch about that surface while keeping the vehicle in the target trajectory. The workspace is defined as a 3-D space where the sliding surface is defined by fitting weighted spline functions on the coordinates of the intended trajectory to define the stable sliding surface whose stability lever increases as the vehicle moves towards the target point. Preliminary results compare the trajectories followed by the quad-copter and the intended trajectories by using the mean square deviation. As would be expected, the performance depends heavily on the speed of the quad-copter; higher speeds on sharp curvature are associated with large tracking errors than low speeds on similar curvatures, while the performance on straight line paths was considerably good. This is most likely due to the switching speed because it seems that higher speeds should be associated with higher switching speeds also. The future work intends to study if parameterizing the 3-D splines using speed and time can improve the tracking performance where the switching rate will be made to be proportional to the number of spline functions that define the trajectory irrespective of the speed of the quad-copter.
Stochastic Analysis of the Carbon Nanotube Network Interphase in Dry and Pre-Infused Buckypaper
Authors: Yekani Fard Masoud , Perrino Samuel , Hedman Conor 
Published: February 2023

Abstract
Assembling CNTs into a thin film Buckypaper (BP) effectively creates high CNT content nanocomposites. BP consists of entangled CNT networks with a porous 3D structure in which CNTs are randomly distributed. The interaction between the dispersed CNT and the polymer or between the CNT network and the surrounding polymer occurs via interphase. The interphase is the region between two constituents and has different local morphology and properties than the constituents. The morphology and properties of the interphase between the CNT network and polymer have not been given enough attention in the literature. Atomic Force Microscopy-based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique has been used to characterize the CNT network interphase at the nanoscale with high lateral resolution. Probe actual stiffness, tip radius, tapping force, deformation level, and deflection sensitivity for heterogeneous BP are discussed. The nano-scale material properties are extracted from the DMT contact mechanic’s model. The authors show that reduced modulus and deformation can examine the interphase zone thickness and properties. Weibull model is used to investigate the distribution of an interphase thickness and the size of the CNT network.
Hybrid Manufacturing Decomposition Rules and Programming Strategies for Service Parts
Authors: Urbanic Ruth Jill , Hedrick Bob , Ramezani Hamoon , El Moghazi Sandy , Saghafi Marzie 
Published: February 2023

Abstract
For service parts, production runs are ‘on demand’, and managing the inventory for components or the tooling is expensive. Additive manufacturing (AM) processes lend themselves to this application as their key strength is the ability to fabricate components with no tooling or fixtures. However, several AM processes require significant post processing to remove support materials as well as generate the required surface finishes and feature tolerances. The main purpose of this research is to determine whether a directed energy deposition (DED) AM solution can be used to manufacture selected components that are presently cast, machined, or forged using hybrid manufacturing build solutions, where machining operations are introduced as required. Select DED AM processes are used to fabricate a near net shape, and either final machining or interspersed machining operations are included. A product-process classification schema is introduced to cluster similar build strategies. This provides the background for the decomposition approaches and the process planning strategies. The build times and material usage are included and component redesign is discussed to facilitate the manufacturing process and optimize the design. This is ongoing research and, in future work, an analysis of the heat maps and the resulting mechanical and physical properties will be evaluated for these components.
Effects of the CNT Network Size and Interphase on Mode I Fracture of Buckypaper Nanocomposites
Authors: Yekani Fard Masoud , Raman Rohan , Orozco Yesenia , Tata Aditi 
Published: February 2023

Abstract
Buckypaper (BP) is a complex 3D CNT structure with randomly distributed CNTs. The size of the CNT network and interphase can potentially affect the fracture behavior of BP nanocomposite on a larger length scale. For multiwall carbon nanotube BP, the main pore sizes range between 20–35 nm (intrabundle) and 65–110 nm (inter bundle). Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) have proven nano and sub-micron inhomogeneities in BP membranes. These inhomogeneities affect the macroscale mechanical response of BP membranes due to the local high modulus mismatch among CNT particles, the CNT networks, and the polymer. The geometry (shape and size) and the spatial locations (depth and distance between the networks) of the buried CNT networks are amongst critical parameters for the degree of the mechanical mismatch. Atomic Force Microscopy-based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique is used to quantify the nano- and micro-properties of CNT networks and interphase. Double Cantilever Beam (DCB) specimens are used for mode I fracture characterization. The compliance Calibration technique is used to calculate the initiation and propagation energy release rate. The authors use the Weibull model to examine material properties’ statistical distribution. Weibull statistics link the probability of an event such as CNT network size and interphase thickness.
Effect of Using 3D Printed Parts on the Torque-Tension Relationship of Threaded Joints
Authors: Robusto Francesco , Nassar Sayed A. , Lee Joon Ha , Gerini-Romagnoli Marco , De Agostinis Massimiliano 
Published: February 2023

Abstract
This study investigates the effect of shot-peened additively manufactured aluminum parts on the torque-tension relationship of threaded joints, as compared to extruded components. Steel flange head bolts are utilized. A computer-controlled RS torque-tension system is used for tightening test joints to a target preload, and frictional data is collected at a high sampling rate. A final group of additive manufactured specimens is analyzed to evaluate the effect of machining on the tribological response of the bolted joint. The underhead friction coefficient is measured over 5 consecutive tightenings, with and without disassembly and cooldown. The bearing surface topology is analyzed using an optical profilometer after each tightening. Fasteners and parts are ultrasonically cleaned, and tests are performed with no lubrication. Cooldown between consecutive tightenings had a significant effect on the frictional characteristics of non-machined additively manufactured joints. The lower surface integrity of the 3D printed components resulted in severe damage to the bearing surface after 5 tightening operations. Discussion of the results and conclusions are provided.
Enhancing the Performance Measures of Abrasive Water Jet Machining on Drilling Acrylic Glass Material
Authors: Shanmugam Ragavanantham , T. Geethapriyan , Thangaraj Muthuramalingam , Ramoni Monsuru 
Published: February 2023

Abstract
Abrasive Water jet Machining finds its application on extensive range of materials. Both ductile and brittle materials can be machined by this process, but the material removal is different in both the cases, i.e., by Ductile fracture and Brittle fracture respectively. When it comes to brittle materials, conventional machining processes cannot be used due to a number of limitations of the material. Thus, non-conventional machining is a rather preferable choice for brittle materials. However, the quality of machining might vary, as it is dependent on some input parameters such as — Abrasive size, Water jet Pres-sure and Abrasive Flow rate. The quality of the machining for a drilling operation is evaluated based on the hole parameters i.e. — Circularity, Taper ratio, Overcut and Material Removal Rate (MRR). The process parameters are varied in accordance to the desirable outcome to be obtained. Outcomes like MRR and circularity are required to be maximized, whereas Taper ratio and Overcut have to be minimized. The effects and interactions between different parameters on the outcomes are studied using Analysis of Variance (ANOVA).
On the Development and Evaluation of a Framework for Brain-Computer Interface and Vibrotactile Feedback for Human-Robot-Interaction in Virtual Spaces and Robotic Hardware
Authors: Hazra Sudip , Whitaker Shane , Shiakolas Panos S. 
Published: February 2023

Abstract
Research in Brain-Computer Interface (BCI) aims to understand human intent with the goal to enhance Human-Robot Interaction (HRI) especially in the field of assistive robotics. The goal of this research is to develop a behavioral sequence based framework to help persons with upper limb disabilities to maintain self-dependence. The framework aims to operate in stages and links multiple functional components to identify human intent and control a robotic arm. The development, operation, and evaluation of the framework and the linked functional components to acquire, process, evaluate, and map BCI signals generated using facial expressions and head movements to predefined actions will be introduced.The framework will integrate multiple functional components such as a non-invasive BCI control device, a vibro-tactile haptic feedback device, a visual feedback environment, the evaluation and training platform, and a robotic arm. The robot pick, move and place actions are mapped to different facial expressions and presented using haptic and visual feedback to the user for classified action verification before performing the process using a robotic arm. The initial evaluation of the developed framework was 100% successful with two volunteers who also provided constructive feedback. The initial successful evaluation provides confidence to further test the framework with more volunteers to identify limitations and/or areas of improvement and its application for further research in HRI as it applies to assistive robotic systems.
A Topology Optimization Methodology With Vibration Constraint for an Aerospace Bracket Design
Authors: Karabiyik Hüseyin , Eroglu Osman , Metin Eskimez Muhammed , Oncul Berk Oncu , Yilmaz Muhammet Tayyip , Gökdağ İstemihan , Gorguluarslan Recep M. 
Published: February 2023

Abstract
The most important need in the aviation industry is the realization of high-strength and lightweight designs. For this reason, topology optimization methods have become widespread recently. Besides, meeting the natural frequency requirements is one of the important design elements. However, topology optimization with stiffness maximization requires a static finite element analysis evaluation while the natural frequency calculation requires a modal analysis evaluation. Using these two different analysis procedures at the same time in the topology optimization process, on the other hand, is a challenging task. To address this challenge, a topology optimization methodology that accounts for the natural frequency constraint in a compliance minimization process is presented in this study. Since the commercial software can either minimize compliance or minimize the vibration frequency at one time, using these two different analysis procedures at the same time together stands out as an innovative aspect of this study. The applicability of the developed methodology is shown for two bracket designs; namely, the so-called GE bracket and a real-world satellite bracket with natural frequency and mass constraints. The prototypes of the designs are fabricated using the additive manufacturing technique.
The Effect of Multi-Stage Age Treatment on Mechanical Properties of 7075 Al Alloy
Authors: Rahman A. H. M. E. , Abu-Mahfouz Issam , Banerjee Amit , Wisniewski Johnmark 
Published: February 2023

Abstract
One of the widely used aerospace alloys is 7075 aluminum alloy (AA) because of its high tensile and compressive strength and good response to exfoliation corrosion. A solution heat treatment followed by artificial ageing is known as T6 temper designation was initially used to obtain peak strength for 7075 AA. The artificial aging, done at 115°C to 130°C (T6 temper), increases strength of 7075 AA to a peak level then decreases, however, resistance to stress-corrosion cracking is decreased. Recent trend shows that the strength can be increased more by applying multi-stage aging process. This research focuses on the effect of multiple aging temperature, time on the mechanical properties of 7075 aluminum alloys. ASTM standard coupons were machined from an as received aluminum plate and applied different combination of RRA age treatment. The initial results on mechanical properties are reported. The maximum tensile strength obtained was over 100 ksi for a double RRA at 200°C for 10 min. The hardness was measured using a micro hardness tester. The Vickers hardness numbers were within the range in literatures.
A Mapping Approach to Achieve Torque Control for Parallel-Actuated Robotic Systems
Authors: Welch Stephen B. , Runyon Christian D. , Beiter Benjamin C. , Herron Connor W. , Kalita Bhaben , Leonessa Alexander 
Published: February 2023

Abstract
In this work, we present an approach for realizing the torque control for a parallel-actuated robotic system by mapping the motion of a linear series elastic actuator (LSEA) to its driven robot joint. In most standard robotic modeling and control strategies, a robot is assumed to be actuated by torques applied directly at each joint and constructed as an open kinematic chain. However, the use of non-direct-drive actuators can violate these assumptions, causing additional challenges for the modelling and control of the robot. On our humanoid robot we use standard high level controllers to command desired joint positions and torques in order to generate desired behaviors. However, the humanoid robot is actually actuated by LSEAs, which are defined by actuator length and force. Overcoming this difference requires a method of mapping the motion and effort of an LSEA onto the corresponding joint of a robot. Our mapping approach allows for the conversion of generic desired joint position and torque trajectories consistent with standard controllers into actuator length and force trajectories that can be implemented on an LSEA-actuated robot. We present a two-stage methodology to achieve low-level torque control on our humanoid robot: a validation of the force-torque mapping in simulation, and a force controller implementation for tracking these resulting torque trajectories on a sample simulation of a single robot joint.
Development of a Bio-Inspired Hopping Leg for Lunar Exploration Rover
Authors: Nguyen Mary , Salai Elizabeth , Smith Andrew , Barth Andrew , Dong Janet , Ma Ou 
Published: February 2023

Abstract
The goal of this project is to develop and build a jumping robotic leg to be mounted in a rover for lunar terrain exploration. As we may know that most rovers are using wheels for locomotion, the purpose of replacing the wheels with a jumping robotic leg in this project is to enhance the ability of rovers to travel further distances in a shorter time. The improved speed and distance will make lunar missions more efficient on resources and time. The leg design also helps prevent a rover from getting stuck on the exploration due to geographic obstacles such as mountains, canyons, and other miscellaneous terrains. While this idea is not new, this project attempted to create a unique design using the biomechanics of a kangaroo leg to improve jump capabilities such as height and speed. It is expected that a kangaroo-inspired rover model offers a faster speed and better locomotive capacity in the low gravitational environment and allows the rover to navigate the rough lunar terrain more efficiently in comparison to a wheeled rover.
Three student teams have been working on this project in different academic years. This year’s team focuses on improving jumping height through energy conservation and reduction of weight. The new three-link leg spring mechanism model is designed, built, and tested. The hop is generated by an actuation system that includes three springs and a pull cable. In the design phase, a CAD model was created, and the jumping leg’s static analysis and dynamic simulation were conducted. The jumping heights were calculated and compared with theoretical calculation and simulation. The conservation of energy law was applied to solve the jump height for the theoretical calculation. In the dynamic simulation, the jump height was measured and recorded by adjusting several leg parameters. The jump heights from the calculation and dynamic simulation were compared. The optimum design of the leg, therefore, was determined to achieve the best jumping height.
This paper will discuss the process of this year’s senior team to develop this bio-inspired hopping rover for lunar exploration. The leg prototype was built and made of ABS plastic, and it stands 50 cm high with a weight of 1.56 kg. A testing rig was also developed to measure the leg’s jumping height. This bio-inspired rover could pave the way for improved mobility in unknown, rugged terrains and low gravity environments by overcoming the limitations of the wheeled rovers altogether. This model could lead to the pioneering of using the flexibility of locomotion and miniaturization for lunar exploration.
Extended Analysis of Micro Fin Array Configurations for Single- and Two-Phase Flow
Authors: Frear Colton , Carbajal Gerardo , Romero-Ramirez Edwar 
Published: February 2023

Abstract
An experimental study was conducted to compare heat transfer performance between three micro fin array configurations for transient and steady periodic operation. The study evaluates the time a microchannel takes to reach steady-state conditions for a given flow rate and heat input. It is crucial to investigate the response of the thermal device to overcome a sudden overheating. The experiment aims to analyze the effects of flow boiling in microchannels for extended periods. The study focuses on three novel microchannel cooling devices with different micro fin array configurations. The first design consists of an array of parallel straight fins. The second design resembles the first with the addition of diagonal cuts separating the channel into segments. The third and final design adds another set of diagonal cuts in the opposite direction, creating a diamond lattice of micro fins. It is believed that adding flow-disrupting geometries such as those found in designs 2 and 3 will be beneficial for both single and two-phase flow by improving flow mixing and reducing flow instability, respectively. The experimental results of each fin configuration were compared against a smooth plate (dummy channel) used as a reference. Each device was tested at flow rate of 0.1 to 0.5 ml/min at different heat inputs up to 500W. Temperature and pressure sensors located at the inlet and outlet of the channel measured and gathered fluid data every second for 1800 seconds. The surface temperature near the center of the channel was also collected every second. Once the system achieved steady-state conditions, the surface temperatures at the inlet and outlet of the plate were gathered to ensure correct readings. For this experiment, distilled water is the selected working fluid. Previous experimental studies have shown that adding turbulence caused by cut segments, like those in designs 2 and 3, may significantly improve the heat transfer effectiveness for flow boiling. The experimental results revealed a heat transfer enhancement during flow boiling for designs 2 and 3. Furthermore, for single-phase flow at low heat inputs, the straight parallel micro fins array exerted the highest pressure drop. The pressure drops for designs 2 and 3 were similar during flow boiling. The present study included the straight fin array design to a variable flow rate and increment heat input every 300 seconds. It was found that while the surface temperature data can easily be used as a reference to determine the onset of flow boiling, it cannot be used to detect flow instability effectively. Conversely, the pressure drop across the device provides valuable data for determining the onset of flow instability but is not very effective when used to assess flow boiling. As a result, a composite plot overlaying the surface temperature and pressure drop of the device over time is a great way to determine the onset of each phenomenon simultaneously.