Virtual Assembly Research Articles

A Virtual Assembly Technology for Virtual–Real Fusion Interaction of Ship Structure Based on Three-Level Collision Detection

With the rapid advancement of new-generation information technology, the virtual–real fusion interaction has increasingly become a crucial technique for structural analysis to determine the strength envelope of hulls. A high-precision assembly of the experimental devices in a virtual environment is vital. A virtual assembly method for a structural virtual–real fusion test based on the oriented bounding box (OBB) algorithm, the Devillers and Guigue algorithm, and differential triangle facets algorithm are proposed in this paper. The experiment of the connector in a typical offshore floating platform is performed as a case, which indicates that the virtual assembly method proposed in this paper enables the assessment of assembly virtually prior to the actual experiment, and the assembly accuracy can reach 0.01 mm. The digitalization and virtual–real fusion interaction for the mechanical experiment of hulls are advanced to ensure efficiency, safety, and economy.

AI can help humans find common ground in democratic deliberation.

Finding agreement through a free exchange of views is often difficult. Collective deliberation can be slow, difficult to scale, and unequally attentive to different voices. In this study, we trained an artificial intelligence (AI) to mediate human deliberation. Using participants' personal opinions and critiques, the AI mediator iteratively generates and refines statements that express common ground among the group on social or political issues. Participants (N = 5734) preferred AI-generated statements to those written by human mediators, rating them as more informative, clear, and unbiased. Discussants often updated their views after the deliberation, converging on a shared perspective. Text embeddings revealed that successful group statements incorporated dissenting voices while respecting the majority position. These findings were replicated in a virtual citizens' assembly involving a demographically representative sample of the UK population.

Effect of neutron beam properties on dose distributions in a water phantom for boron neutron capture therapy.

From the viewpoints of the advantage depths (ADs), peak tumor dose and skin dose, we evaluated the effect on the dose distribution of neutron beam properties, namely the ratio between thermal and epithermal neutron fluxes (thermal/epithermal ratio), fast neutron component and γ-ray component. Several parameter surveys were conducted with respect to the beam properties of neutron sources for boron neutron capture therapy assuming boronophenylalanine as the boron agent using our dose calculation tool, called SiDE. The ADs decreased by 3% at a thermal/epithermal ratio of 20-30% compared with the current recommendation of 5%. The skin dose increased with the increasing thermal/epithermal ratio, reaching a restricted value of 14 Gyeq at a thermal/epithermal ratio of 48%. The fast neutron component was modified using two different models, namely the 'linear model', in which the fast neutron intensity decreases log-linearly with the increasing neutron energy, and the 'moderator thickness (MT) model', in which the fast neutron component is varied by adjusting the MT in a virtual beam shaping assembly. Although a higher fast neutron component indicated a higher skin dose, the increment was <10% at a fast neutron component of <1 × 10-12Gycm2 for both models. Furthermore, in the MT model, the epithermal neutron intensity at a fast neutron component of 6.8 × 10-13Gycm2 was 41% higher compared with that of 2 × 10-13Gycm2. The γ-ray component also caused no significant disadvantages up to several times larger compared with the current recommendation.

An efficient framework for design optimization using parametric reduced order modeling in a virtual prototyping phase

Virtual Prototype Assembly is a tool enabling the virtual assembly of components, the prediction of noise and vibration performance, and the evaluation of component modification scenarios. FRF-based substructuring is the technique used to assemble the components, either obtained from experimental measurements or numerical simulation models. However, numerical simulations of components can be time-consuming, especially when exploring several component design modifications of large models. The paper proposes a framework combining Virtual Prototype Assembly with a parametric Model Order Reduction technique for vehicle design optimization. The proposed parametric Model Order Reduction technique generates a Reduced Order Model of a component maintaining an explicit dependency on material parameters and properties, such as: Young's Modulus, density, Poisson coefficient, connection stiffness, etc.. This enables fast and efficient simulation of components designs without the need of recomputing numerical models, thus streamlining the component design optimization process. The effect of component design modifications will be assessed at the predicted target vibration levels on an academic application case.

Measurement and optimization method for aero-engine rotors based on binocular multi-line laser sensing and virtual assembly

During the assembly of aero-engine rotors, eccentricity and tilt errors along the radial and axial direction result in uneven loading along the mating surface, which significantly impacts the operational lifespan of the rotor. This paper proposes a three-dimensional contour measurement system based on binocular multi-line laser sensing and conducts an aircraft engine rotor stacking virtual assembly technology system, to response the practical requirements of aircraft engine rotor unit production assembly engineering. We combine multi-line structured light active projection device with the binocular stereo vision model to construct the contour measurement system, which enhances the surface features of the projected object by adhering to the common constraint of structured line and stereo vision. Furthermore, the error propagation model for multi-stage rotor assembly to investigate the mechanism of error impact is established aiming to facilitate quantitative research on virtual assembly mechanisms. By manipulating the rotor phases and evaluating the coaxiality under various conditions, effective prediction of phase variation can be achieved, the multi-objective benchmark virtual assembly method based on the error propagation model of multi-stage rotor coaxiality is presented. The experimental results indicate that the proposed measurement system achieves the maximum disparity between the spatial data points procured by the proposed measurement system and the predetermined value of 2.1 μm, and the maximum disparity between the target plane’s average movement distance and the preset value of 3.7 μm. The precision provided by this system effectively meets the objective of assembly phase optimization for multi-stage rotors. In the empirical experiment conducted on the three-stage rotors, both systems yielded identical optimized phases: 0° for the first-stage rotor, 270° for the second-stage rotor, and 120° for the third-stage rotor, thereby validating the efficacy of the proposed measurement and optimization method for aero-engine multi-stage rotors with virtual assembly.

Sistem Jual Beli Online dalam Perspektif Hukum Islam: Studi Kasus di Facebook Temanggung

This reseach contains at study of online buying and selling systems in the perspective of islamic law in tehe buying and selling process of online facebook grups for wong temanggung. This research uses deskriptive qualitative research menthods. The results of this study found that there was a sale and purchase that me the requirements and harmony, but someting the seller and buyer met in a virtual assembly because sellers and buyers are not in one country sometimes meet face to face for affordability place according to the rules written on facebook.

Exploring the Integration of Visual Assembly Process Among the 3C Manufacturing Firms in China

The study delved into the visual assembly process planning and information systems within the context of the ever-evolving manufacturing landscape. The manufacturing sector had witnessed a shift from traditional assembly methods, often plagued by inefficient manual processes, to a more technologically advanced approach involving 3D visualization and information systems. The aim of this study was to improve assembly processes' efficiency, accuracy, and flexibility. Incorporating insights from existing literature, the study outlined the significance of visual assembly process planning using immersive virtual reality and virtual reality technology in enhancing assembly efficiency and product quality. Additionally, the study emphasized the impact of digital assembly based on virtual assembly process planning on productivity and quality. These technologies optimized the assembly process, reduced errors, and improved product quality, with practical applications for the manufacturing industry. Nonetheless, challenges, including system integration issues, had hindered the seamless integration of assembly systems and technologies, affecting efficiency and quality. To overcome these challenges, a comprehensive plan was presented. This plan spanned various aspects of manufacturing, such as organizational structure, product diversification, workforce optimization, technology integration, quality enhancement, and cost reduction, culminating in profitability enhancement. The research provided valuable insights for academia and practice, offering a promising path to optimizing production processes, improving assembly efficiency and quality, and reducing carbon emissions. In the face of global climate change, the integration of visual assembly processes in 3C manufacturing enterprises held the potential to enhance competitiveness and contribute to sustainable development.

Development of a dedicated process simulator for the digital twin in apparel manufacturing: a case study

PurposeThe purpose of this study is to introduce a dedicated simulator to automatically generate and simulate a balanced apparel assembly line, which is critical to the digital twin concept in apparel manufacturing. Given the low automation level in apparel manufacturing, this is a first step toward the implementation of a smart factory based on cyber-physical systems.Design/methodology/approachThe mixed task assignment algorithm was implemented to automatically generate a module-based apparel assembly line in the developed simulator. To validate the developed simulator, a case study was conducted using process analysis data of technical jackets obtained from an apparel manufacturer. The case study included three scenarios: calculating the number of workers, selecting orders based on factory capacity and managing unexpected worker absences.FindingsThe developed simulator is approximately 97.2% accurate in assigning appropriate tasks to workstations using the mixed task assignment algorithm. The simulator was also found to be effective in supporting decision-making for production planning, order selection and apparel assembly line management. In addition, the module-based line generation algorithm made it easy to modify the assembly line.Originality/valueThis study contributes a novel approach to address the challenge of low automation levels in apparel manufacturing by introducing a dedicated simulator. This dedicated simulator improves the efficiency of virtual apparel assembly line generation and simulation, which distinguishes it from existing commercial simulation software.

Improved pass-through dimensionality reduction for point cloud contour extraction

Obtaining a point cloud model that considers the overall information of large steel components as well as the local information of bolt holes is an important approach for the virtual assembly of large steel structures. A point cloud extraction method to improve the uniformity of the dimensionality reduction distribution is presented. Firstly, point cloud data characterising the overall information of a large-size component and local information of the bolt-hole group are obtained by combining vertical three-dimensional (3D) laser scanning and handheld 3D laser scanning. The point cloud is then triaxially equidistant and reduced in dimension based on improved straight-pass filtering and the corner point cloud is extracted using a planar point cloud distribution uniformity algorithm. Finally, the point cloud is restored to the same space to complete the contour extraction of the point cloud. The accuracy of the contour extraction method was verified by conducting point cloud feature extraction tests using standard components. Compared with conventional feature extraction, the method provides targeted local feature extraction for bars with a certain regularity of geometric configuration, reducing the time required for feature extraction and providing a brief database for the virtual assembly of steel joist beams.

Evaluation of mental workload in haptic-enabled virtual assembly training operations

Evaluation of mental workload in haptic-enabled virtual assembly training operations

Learnings from developing a custom virtual assembly environment for mountability issues of cooling cabinets

AbstractVarious industries use computer simulation for verifying product properties in early phases of development. Traditionally, such properties include the stability of mechanical structures or the efficiency of aircraft turbines. More recently, research also focuses on the mountability of industrial products using virtual assembly. While research on virtual assembly already started in the mid-1990s, the applicability in different industries remains largely unclear today. To advance the state-of-the-art, in this paper we present learnings from developing a virtual assembly environment for cooling cabinets.

Game changer: Cloud‐based classroom interactions powered by Google Sheets

AbstractThe COVID‐19 pandemic forced instruction into remote formats, rendering active learning efforts in business classrooms infeasible. In response, we adopt a novel model for interactive classroom activities by hosting classroom games on Google Sheets, the free and widely used cloud‐based spreadsheet application. First developed for a synchronous Zoom class during the COVID‐19 pandemic, this approach was integrated into face‐to‐face courses in two countries. Due to its instructional flexibility, minimal need for resources, and tendency for student acceptance, using Google Sheets for classroom interaction has far‐reaching educational applications beyond the pandemic era. To illustrate this approach, we introduce three operations and supply chain management activities created on Google Sheets: the Virtual Assembly Line (VAL) activity, the Just‐in‐time Game, and the Dice Game. An in‐depth examination of implementing these activities in the classroom offers practical insights into the benefits of utilizing cloud‐based classroom games in teaching. Furthermore, a comparison of test results between students who played the game and a control group showed significantly improved learning outcomes. We also discuss how this approach could foster active learning adoption in environments traditionally less conducive to such practices, such as remote instruction and large enrollment classes.

Virtual trial assembly of large steel members with bolted connections based on multiscale point cloud fusion

AbstractVirtual trial assembly (VTA) using 3D laser scanning as the digital carrier can overcome the shortcomings of time‐consuming and costly physical preassembly. However, its application in large steel structures with bolted connections remains limited. First, this study introduces a novel approach for acquiring multiscale point cloud data of large steel members using terrestrial laser scanners (TLSs) and hand‐held scanner (HHS). This approach considers both the global data and the local details of the steel members. Additionally, a precise registration method based on magnetic 3D targets is proposed for multiscale point clouds, which enables the registration accuracy of multisource point clouds to reach submillimeter precision. Subsequently, a novel algorithm for feature point screening is introduced, which utilizes a dichotomous point cloud grid approach to identify and extract a significant quantity of bolt holes effectively. This approach enables fully automated and fast extraction of the point cloud on the cylindrical inner surface of the holes. Finally, the bounding box and Procrustes analysis approach are employed to perform VTA using the point cloud of the cylindrical bolt holes as the assembled features. The accuracy and feasibility of the above method are verified by a down‐scale modeling experiment and project test, which provide technical support for the VTA of large steel truss structures.

Research on the design and application of 3D scene animation game entertainment system based on user motion sensing participation

Developed a 3D indoor virtual scene assembly system based on dual touch screen. The system adopts a combination of 2D views and 3D views. The 2D and 3D views are displayed on the two touch screens. We have comprehensively designed various interactive operations of 2D view and 3D view from the perspectives of simplicity, easy learning and easy to use, and reduced the complex 3D interactive operations to 2D interactive operations. Users can conduct two-dimensional interactive operation and 3D interactive operation based on two display screens, which can realize the efficient assembly of 3D virtual scene. The results indicate significant differences in the number of modifications of mode A and B (t = 2.982, p = 0.006 < 0.01), effective design time (t = 4.990, p < 0.001), first design satisfaction (t = 5.074, p = <0.001) and final design satisfaction (t = 2.787, p = 0.010 < 0.05). Participants in mode A had fewer modifications and shorter effective design times compared to mode B. Study and design a new workbench supporting the collaborative design of 3D virtual scenes. The workbench can support a three-dimensional indoor virtual scene assembly system based on dual touch screen, and designers and users can assemble the virtual scene together. The workbench mainly consists of two touch displays and a holographic display device. The holographic display device displays the three-dimensional scene designed by the user in real time, and supports the designer and the user to operate the three-dimensional scene through the touch film attached to it. Touch display enables designers and users to assemble scenes on 2D views through simple touch operations such as drag and drop. The face-to-face collaborative design method provided by the workbench is more conducive to the communication between designers and users, so as to improve the design efficiency of 3D scenes.

Optimalisasi produktivitas pengupasan biji kopi melalui modifikasi mesin pengupas

The aim of this research is to modify the coffee bean husking machine to enhance the quality and efficiency of the husking process. The modifications include the addition of a spring mechanism in the grinding space, enabling the outer roller to move flexibly in accordance with the size of the entering coffee beans. Furthermore, these changes also consider reducing the percentage of broken coffee beans during the husking process. The machine underwent two rounds of testing, with three samples tested under two different drying conditions. The research results demonstrate the success of the modifications in achieving their objectives. The machine's capability to husk coffee beans up to the parchment layer, not just the husk, indicates an improvement in the quality of the husking process. The quantity of successfully husked coffee beans also increased, while the percentage of broken beans decreased. By enhancing the quality and quantity of coffee beans produced by this machine, the modifications can significantly benefit coffee farmers. Additionally, this study utilized Autodesk Fusion 360 software to enable virtual assembly of machine components before physical production. The outcomes of the virtual assembly aided in understanding the machine's functionality and the interactions among its components. Therefore, the modifications to the coffee bean husking machine have assisted coffee farmers in producing higher-quality beans and expediting the coffee processing process.

Research on digital assembly method of large-caliber optomechanical systems

Developing optomechanical systems with large-aperture output beams is increasingly important for deep space exploration, homeland defense, and modern warfare. However, the assembly process for such systems is becoming more challenging due to their complexity and size. Considering that traditional computer-aided assembly methods for optomechanical systems primarily prioritize debugging and testing, often overlooking the importance of feasibility analysis and verification in the assembly process, this paper presents a digital assembly method for large aperture optomechanical systems that integrates virtual assembly technology with misalignment error detection technology. By combining these two technologies, the proposed method aims to enhance the assembly process by providing a more comprehensive approach that includes feasibility analysis and verification, in addition to debugging and testing. Firstly, virtual assembly technology is utilized to simulate and validate the assembly process design of optomechanical systems. Secondly, a second-order sensitivity matrix method is proposed to achieve higher accuracy in solving misalignment compared to traditional methods. The new method is validated through simulation experiments on an off-axis beam expander system, showing superior solving accuracy compared to traditional approaches. Lastly, an actual assembly and adjustment platform is constructed, and the obtained assembly result exhibits a wavefront aberration RMS value better than 0.016λ (λ=632.8nm).

A second-order tolerance analysis approach to statistical virtual assembly for rigid parts

Virtual assembly has become a popular trend in recent years and is used for various purposes, including selective assembly and adaptive tooling. Monte Carlo approaches based on Finite Element Method (FEM) simulations are commonly used for production applications. However, during the design phase, when testing different configurations and design options, a variational method is more suitable. This paper aims to test different implementations of the Method of System Moments applied to the second-order tolerance analysis method when actual distributions, which are non-centered and non-normal, are used as input for the simulation. The study reveals that the simulation results can significantly vary depending on the simulation settings in some cases. As a result, a series of best practices are highlighted to improve the accuracy and reliability of the simulation outcomes.

Extraction of Feature Information from Point Cloud of Large Volume Steel Truss Members

In order to address the issues pertaining to the subjective nature and limited precision associated with selecting feature points in the point cloud of a large steel truss structure, this study proposes a batch automatic extraction approach for identifying key feature information, including boundaries, corner points, and bolt holes of large steel truss components. This method relies on the nested application of established processing algorithms such as Euclidean clusters, regional growth clusters, and random sampling consensus. In addition, a novel approach is suggested for validating the precision of feature information extraction through the utilization of standard theoretical models. The results of the experimental and large-scale lower chord tests demonstrate that our approach is not dependent on specialized software, exhibits excellent efficiency, and possesses an acceptable degree of automation. The findings of this study can provide accurate data support for reverse modeling, virtual trial assembly, and dimensional inspection of steel truss components.

A case study of virtual CNC machine tool assembly and human-computer interaction techniques

When it comes to the virtual machine tool assembly process, there are problems such as assembly errors. Based on the general idea of correct assembly, it is proposed to innovate the assembly process by utilizing the enclosing box and separating axis theorem and GJK algorithm, so as to monitor the state of the detection process, which verifies the effective feasibility of the monitoring method and provides a new idea for the assembly process of virtual CNC machine tools.

Precision Regulation in Multistage Aero-Engine Rotors With Curvic Couplings Using Line-Structured Light Array Scanning and Virtual Assembly

Precision Regulation in Multistage Aero-Engine Rotors With Curvic Couplings Using Line-Structured Light Array Scanning and Virtual Assembly