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Introduction
Publications
Publications (388)
Modern manufacturing faces significant challenges, including efficiency bottlenecks and high error rates in manual assembly operations. To address these challenges, we implement artificial intelligence (AI) and propose a gaze-driven assembly assistant system that leverages artificial intelligence for human-centered smart manufacturing. Our system p...
Laser-foil-printing (LFP) is an additive manufacturing (AM) technique offering advantages over traditional powder-based methods. A deeper understanding of the melt pool dynamics is crucial for optimising process parameters and achieving high-quality builds. This paper presents a combined approach utilising numerical simulations and in-situ thermogr...
Additive manufacturing (AM) allows sensor embedding with the freedom of geometry flexibility. This research aims to experimentally determine the viability of integrating Platinum resistance temperature detectors into AM 304L stainless steel parts using laser foil printing (LFP) for real-time measurement applications. Using metal foils as a feedstoc...
Purpose
This paper aims to present spot pattern welding (SPW) as a scanning strategy for laser-foil-printing (LFP) additive manufacturing (AM) in place of the previously used continuous pattern welding (CPW) (line-raster scanning). The SPW strategy involves generating a sequence of overlapping spot welds on the metal foil, allowing the laser to for...
The quantification of repetitive movements, known as repetitive action counting, is critical in various applications, such as fitness tracking, rehabilitation, and manufacturing operation monitoring. Traditional methods predominantly relied on the estimation of red-green-and-blue (RGB) frames and body pose landmarks to identify the number of action...
This paper presents a novel approach to unmanned aerial vehicle (UAV) control through electrooculography (EOG) based eye movement tracking. The research focuses on developing an interface that translates eye movements into UAV navigation commands, showcasing a unique integration of biometric technology in UAV (i.e., drone) control. To measure horiz...
Oxidation behavior of additively manufactured ZrB2–SiC in air and in CO2 is reported in the temperature range of 700–1000 °C. Observed scale morphologies in air and in CO2 were similar, featuring an outer borosilicate layer and an inner porous zirconia layer containing partially oxidized silicon carbide particles and remnant borosilicate products....
Hydrogels are a key component in bioinks and biomaterial inks for bioprinting due to their biocompatibility and printability at room temperature. The research described in the present paper contributes to the advancement of bioprinting by studying the effect of bioactive borate glass (BBG) incorporated into hydrogels on printability and physical pr...
This research applies Green's function solutions to simulate temperature and thermal stress fields in laser powder-bed fusion (LPBF) processes. Using a semi-infinite domain and 2D Gaussian laser profiles, the analytical model achieves high computational efficiency, has the potential for real-time controls and predictions in LPBF processes. The mode...
Citation: Kolan KCR, Saxena A, Bromet BA, et al. Bioprinting with adipose stem cells and hydrogel modified with bioactive glass. Abstract Bioprinting research is focused on utilizing growth factors and multiple cell types to create clinically relevant three-dimensional (3D) tissue models using hydrogels. Rheological and biological challenges are tw...
Repetitive counting (RepCount) is critical in various applications, such as fitness tracking and rehabilitation. Previous methods have relied on the estimation of red-green-and-blue (RGB) frames and body pose landmarks to identify the number of action repetitions, but these methods suffer from a number of issues, including the inability to stably h...
The thermal transport properties of the powder layer play a crucial role in the process of laser powder bed fusion (LPBF). This paper introduces an in-situ measurement method utilizing active lock-in infrared thermography (LIT) to determine the thermal diffusivity and thickness of the powder layer. The proposed method exhibits great potential for a...
As the extensive research in Additive Manufacturing (AM) shows, the powder characteristics, such as particle size and geometry, play an important role in determining the quality of powder layer and part fabricated with powder-based AM processes. It has been found that spherical particles result in better powder flowability and spreadability. An att...
Assembly activity recognition and prediction help to improve productivity, quality control, and safety measures in smart factories. This study aims to sense, recognize, and predict a worker's continuous fine-grained assembly activities in a manufacturing platform. We propose a two-stage network for workers' fine-grained activity classification by l...
Recent advances in additive manufacturing have led to the development of innovative solutions for tissue regeneration. Hydrogel materials have gained significant attention for burn wound treatment in clinical practice among various advanced dressings due to their soothing and moisturizing activity. However, prolonged healing, pain, and traumatic re...
The powder spreading is a vital step of powder-based additive manufacturing (AM) processes. The quality of spread powder can considerably influence the properties of fabricated parts. Poorly packed powder beds with high surface roughness result in printed part layers with large porosity and low dimensional accuracy, leading to poor mechanical prope...
This study aims to improve the productivity of laser foil printing (LFP), which is a foil-based metal additive manufacturing (AM) process. LFP uses a dual-laser system to fabricate a 3-dimensional part in a layered fashion by performing four steps in each layer: spot welding, pattern welding, contour cutting, and edge polishing, all of which perfor...
Assembly activity recognition and prediction help to improve productivity, quality control, and safety measures in smart factories. This study aims to sense, recognize, and predict a worker's continuous fine-grained assembly activities in a manufacturing platform. We propose a two-stage network for workers' fine-grained activity classification by l...
Ceramic On-Demand Extrusion (CODE) is a paste extrusion-based additive manufacturing process that has been developed for the fabrication of dense ceramic components. This paper presents a study of using the CODE process to build microchannels with ZrB2-SiC aqueous paste for the fabrication of an ultra-high-temperature compact heat exchanger (CHE)....
The powder spreading is a vital step of powder-based Additive Manufacturing (AM) processes. The quality of spread powder can considerably influence the properties of fabricated parts. Poorly-packed powder beds with high surface roughness result in printed part layers with large porosity and low dimensional accuracy, leading to poor mechanical prope...
Ceramic On-Demand Extrusion (CODE) is a direct ink writing process which allows for the creation of near theoretically dense ceramic components with large cross-sections due to oil-assisted drying. Yttria-stabilized zirconia (YSZ) colloidal pastes were used in CODE to produce dense (multi-road infill and ≳ 98% relative density), large continuous vo...
In this poster, we explain the real-time human-robot collaboration using gestures and speech, including I)•Design a real-time, multi-modal communication HYC system based on gesture and speech recognition. II)• Design and recognize dynamic gestures for communication between a human to an industrial robot. II)• Understand human speech and integrate t...
Thickening electrodes is one effective approach to increase active material content for higher energy and low‐cost lithium‐ion batteries, but limits in charge transport and huge mechanical stress generation result in poor performance and eventual cell failure. This paper reports a new electrode fabrication process, referred to as µ‐casting, enablin...
The laser powder bed fusion (LPBF) process is strongly influenced by the characteristics of the powder layer, including its thickness and thermal transport properties. This paper investigates in-situ characterization of the powder layer using thermographic inspection. A thermal camera monitors the temperature history of the powder surface immediate...
As artificial intelligence and industrial automation are developing, human-robot collaboration (HRC) with advanced interaction capabilities has become an increasingly significant area of research. In this paper, we design and develop a real-time, multi-model HRC system using speech and gestures. A set of sixteen dynamic gestures is designed for com...
Particles of AISI 304L stainless steel powder were spheroidized by the induction plasma spheroidization process (TekSphero-15 spheroidization system) to assess the effects of the spheroidization process on powder and part properties. The morphology of both as-received and spheroidized powders was characterized by measuring particle size and shape d...
Purpose
This paper aims to present the development and experimental study of a fully automated system using a novel laser additive manufacturing technology called laser foil printing (LFP), to fabricate metal parts layer by layer. The mechanical properties of parts fabricated with this novel system are compared with those of comparable methodologie...
Future action anticipation aims to infer future actions from the observation of a small set of past video frames. In this paper, we propose a novel Jointly-learnt Action Anticipation Network (J-AAN) via Self-Knowledge Distillation (Self-KD) and cycle consistency for future action anticipation. In contrast to the current state-of-the-art methods whi...
Human Activity Recognition (HAR) using wearable devices such as smart watches embedded with Inertial Measurement Unit (IMU) sensors has various applications relevant to our daily life, such as workout tracking and health monitoring. In this paper, we propose a novel attention-based approach to human activity recognition using multiple IMU sensors w...
The use of gas-atomized powder as the feedstock material for the laser powder bed fusion (LPBF) process is common in the additive manufacturing (AM) community. Although gas-atomization produces powder with high sphericity, its relatively expensive production cost is a downside for application in AM processes. Water atomization of powder may overcom...
Real-time Action Recognition (ActRgn) of assembly workers can timely assist manufacturers in correcting human mistakes and improving task performance. Yet, recognizing worker actions in assembly reliably is challenging because such actions are complex and fine-grained, and workers are heterogeneous. This paper proposes to create an individualized s...
We Introduce a simple yet effective network that embeds a novel Discriminative Feature Pooling (DFP) mechanism and a novel Video Segment Attention Model (VSAM), for video-based human action recognition from both trimmed and untrimmed videos. Our DFP module introduces an attentional pooling mechanism for 3D Convolutional Neural Networks that attenti...
Virtual Reality (VR) technologies provide a realistic, safe, and controllable environment for novice surgeons to practice surgical operations, allowing them to make mistakes without serious consequences, which have been changing the world of surgical training and practice. This book chapter focuses on methodologies and applications of utilizing VR...
The success of laser-foil-printing (LFP) additive manufacturing depends critically on the laser welding of sheet metals onto the substrate or the previous layer during the part fabrication process. The welding can be generally categorized into two modes: conduction mode and keyhole mode. In this study, 304L stainless steel parts fabricated by the L...
With the development of industrial automation and artificial intelligence, robotic systems are developing into an essential part of factory production, and the human-robot collaboration (HRC) becomes a new trend in the industrial field. In our previous work, ten dynamic gestures have been designed for communication between a human worker and a robo...
The Ceramic On-Demand Extrusion (CODE) process has been recently proposed for additive manufacturing of dense, strong ceramic components via extrusion with uniform layered drying. This study focuses on enabling CODE to fabricate functionally graded ceramics. A controlled volumetric flowrate for each ceramic paste was used to achieve a gradient betw...
This study aims at sensing and understanding the worker’s activity in a human-centered intelligent manufacturing system. We propose a novel multi-modal approach for worker activity recognition by leveraging information from different sensors and in different modalities. Specifically, a smart armband and a visual camera are applied to capture Inerti...
Laser Powder-Bed Fusion (L-PBF), often called selective laser melting (SLM), is a powder-bed fusion process in Additive Manufacturing (AM) that uses a laser beam to selectively fuse layers of powder into near net-shape components with little porosity. However, inconsistencies in the part properties due to the presence of defects in as-built compone...
Human-robot collaboration (HRC) is a challenging task in modern industry and gesture communication in HRC has attracted much interest. This paper proposes and demonstrates a dynamic gesture recognition system based on Motion History Image (MHI) and Convolutional Neural Networks (CNN). Firstly, ten dynamic gestures are designed for a human worker to...
Assembly carries paramount importance in manufacturing. Being able to support workers in real time to maximize their positive contributions to assembly is a tremendous interest of manufacturers. Human action recognition has been a way to automatically analyze and understand worker actions to support real-time assistance for workers and facilitate w...
Cellularized scaffolds fabricated with hydrogel do not possess sufficient strength to act as stand-alone implant devices for hard tissue repair and regeneration. A thermoplastic polymer support structure typically provides the structural integrity to scaffolds while cells and growth factors in hydrogel provide biological stimulation for tissue form...
Ceramic On‐Demand Extrusion (CODE) process has been recently proposed for additive manufacturing of strong ceramic components via extrusion. This paper focuses on fabricating 3 mol% yttria‐stabilized zirconia (3YSZ) components using CODE process, and enabling CODE to produce parts with support structures. A colloidal suspension of 3YSZ was develope...
The pore geometry of scaffold intended for the use in the bone repair or replacement is one of the most important parameters in bone tissue engineering. It affects not only the mechanical properties of the scaffold but also the amount of bone regeneration after implantation. Scaffolds with five different architectures (cubic, spherical, x, gyroid,...
Quality and efficiency are crucial indicators of any manufacturing company. Many companies are suffering from a shortage of experienced workers across the production line to perform complex assembly tasks. To reduce time and error in an assembly task, a worker-centered system consisting of multi-modal Augmented Reality (AR) instructions with the su...
Fabrication of dense aluminum (Al-1100) parts (>99.3% of relative density) by our recently developed laser-foil-printing (LFP) additive manufacturing method was investigated as described in this paper. This was achieved by using a laser energy density of 7.0 MW/cm2 to stabilize the melt pool formation and create sufficient penetration depth with 30...
In a human-centered intelligent manufacturing system, every element is to assist the operator in achieving the optimal operational performance. The primary task of developing such a human-centered system is to accurately understand human behavior. In this paper, we propose a fog computing framework for assembly operation recognition, which brings c...
The global escalating cases of skin donor shortage for patients with severe wounds warn the vital need for alternatives to skin allografts. Over the last three decades, research in the skin regeneration area has addressed the unmet need for artificial skin substitutes. 3D bioprinting is a promising innovative technology to accurately fabricate skin...
The performance of Polymer Electrolyte Membrane Fuel Cells (PEMFCs) is highly dependent on the flow distribution and pressure of reactant gases, which are controlled by flow field design. The relative importance of differing supply pressure requirements of flow field designs in PEMFCs is considered here. A First-Law analysis of the auxiliary system...
In a human-centered intelligent manufacturing system, sensing and understanding of the worker's activity are the primary tasks. In this paper, we propose a novel multi-modal approach for worker activity recognition by leveraging information from different sensors and in different modalities. Specifically, a smart armband and a visual camera are app...
Training and on-site assistance is critical to help workers master required skills, improve worker productivity, and guarantee the product quality. Traditional training methods lack worker-centered considerations that are particularly in need when workers are facing ever-changing demands. In this study, we propose a worker-centered training & assis...
In this study we demonstrate that the mechanical properties of 304L stainless steel (304L SS) parts fabricated by the laser-foil-printing (LFP) additive manufacturing process can be enhanced as compared to parts fabricated by the selective laser melting (SLM) technology. The tensile test results indicate that the LFP fabricated parts achieve ˜15% a...
Virtual Reality (VR) and Augmented Reality (AR) technologies have been well researched for decades, and recently they have been introduced to the consumer market and are being applied to many fields. This chapter focuses on utilizing VR/AR technologies for assembly simulations in advanced manufacturing. First, some basic terminologies and concepts...
Three-dimensional (3D) bioprinting technologies have shown great potential in the fabrication of 3D models for different human tissues. Stem cells are an attractive cell source in tissue engineering as they can be directed by material and environmental cues to differentiate into multiple cell types for tissue repair and regeneration. In this study,...
In today’s competitive production era, the ability to identify and track important objects in a near real-time manner is greatly desired among manufacturers who are moving towards the streamline production. Manually keeping track of every object in a complex manufacturing plant is infeasible; therefore, an automatic system of that functionality is...
Production innovations are occurring faster than ever. Manufacturing workers thus need to frequently learn new methods and skills. In fast changing, largely uncertain production systems, manufacturers with the ability to comprehend workers’ behavior and assess their operation performance in near real-time will achieve better performance than peers....
Bioactive glasses have recently gained attention in tissue engineering and three-dimensional (3D) bioprinting because of their ability to enhance angiogenesis. Some challenges for developing biological tissues with bioactive glasses include incorporation of glass particles and achieving a 3D architecture mimicking natural tissues. In this study, we...
One of the polymer additive manufacturing processes commonly used today is fused deposition modelling (FDM). FDM is the process of manufacturing three-dimensional structure through the use of a layer-by-layer printing of the polymer filament. Due to the anisotropic nature of FDM parts, the orientation of the rasters and the build orientation have a...
The application of bulk metallic glasses (BMGs) has been traditionally limited to parts with small dimensions and simple geometries, due to the requirement of fast cooling during the conventional process of casting. This research exemplifies a promising additive manufacturing method, i.e., laser-foil-printing (LFP), to fabricate high-quality BMG pa...