Virtual Simulation Model Research Articles

Digital twin driven human–robot collaborative assembly

This paper discusses an object-oriented event-driven simulation as a digital twin of a flexible assembly cell coordinated with a robot to perform assembly tasks alongside human. The digital twin extends the use of virtual simulation models developed in the design phase of a production system to operations for real-time control, dynamic skill-based tasks allocation between human and robot, sequencing of tasks and developing robot program accordingly. The methodology combines lean methods of manual assembly in human–robot collaboration paving path towards flexible human–robot work teams. The study is validated with an industrial case study involving dexterous assembly tasks.

The Analysis of Dynamic O/D Adjustment for Bicycle Traffic Demand Estimation with AIMSUN Simulation Model: A Case Study of Nakhon Sawan Municipality in Thailand

Aim: This research aimed to present the process of estimating bicycle traffic demand in order to design bike routes that meet the daily transportation needs of the people in Nakhon Sawan Municipality. Methods: The primary and secondary traffic data were collected to develop a virtual traffic simulation model with the use of the AIMSUN simulation software. The model validation method was carried out to adjust the origin and destination survey data (O/D matrix) by running dynamic O/D adjustment. The 99 replication scenarios were statistically examined and assessed using the goodness-of-fit test. The 9 measures, which were examined, included: 1) Root Mean Square Error (RMSE), 2) Root Mean Square Percentage Error (RMSPE%), 3) Mean Absolute Deviation (MAD), 4) Mean Bias Error (MBE), 5) Mean Percentage Error (MPE%), 6) Mean Absolute Percentage Error (MAPE%), 7) Coefficient of Determination (R2), 8) GEH Statistic (GEH), and 9) Thiel’s U Statistic (Theil’s U). Results: The resulting statistical values were used to determine the acceptable ranges according to the acceptable indicators of each factor. Conclusion: It was found that there were only 8 scenarios that met the evaluation criteria. The selection and ranking process was consequently carried out using the multi-factor scoring method, which could eliminate errors that might arise from applying only one goodness-of-fit test measure.

Problems of Constructing the Nuclotron Virtual Model

Problems connected with the Nuclotron virtual simulation model within MADX are considered. The main objective of the study is a more precise specification of the exiting accelerator model, so that the numerical results obtained using MADX are as close as possible to the experimental data obtained in the last Nuclotron runs. The groups of parameters that bring theoretical calculations closer to the experimental data are found via analyzing the impact of the model characteristics on the numerical results.

Transcatheter Mitral Valve Planning and the Neo-LVOT: Utilization of Virtual Simulation Models and 3D Printing.

Transcatheter mitral valve replacement (TMVR) is an emerging alternative for patients with severe mitral valve regurgitation who are considered at high risk for conventional surgical options. The early clinical experience with TMVR has shown that pre-procedural planning with computed tomography (CT) is needed to mitigate the risk of potentially lethal procedural complications such as left ventricular outflow tract (LVOT) obstruction. The goal of this review is to provide an overview of key concepts relating to TMVR pre-procedural planning, with particular emphasis on imaging-based methods for predicting TMVR-related LVOT obstruction. Risk of LVOT obstruction can be assessed with CT-based pre-procedural planning by using virtual device simulations to estimate the residual 'neo-LVOT' cross-sectional area which remains after device implantation. A neo-LVOT area of less than 2cm2 is currently thought to increase the risk of obstruction; however, additional studies are needed to further validate this cutoff value. Three-dimensional printing and personalized computational simulations are also emerging as valuable tools which may offer insights not readily confered by conventional two-dimensional image analysis. The simulated neo-LVOT should be routinely assessed on pre-procedural CT when evaluating anatomical suitability for TMVR.

The Development of a 1-D Integrated Hydro-Mechanical Model Based on Flume Tests to Unravel Different Hydrological Triggering Processes of Debris Flows

Many studies which try to analyze conditions for debris flow development ignore the type of initiation. Therefore, this paper deals with the following questions: What type of hydro-mechanical triggering mechanisms for debris flows can we distinguish in upstream channels of debris flow prone gullies? Which are the main parameters controlling the type and temporal sequence of these triggering processes, and what is their influence on the meteorological thresholds for debris flow initiation? A series of laboratory experiments were carried out in a flume 8 m long and with a width of 0.3 m to detect the conditions for different types of triggering mechanisms. The flume experiments show a sequence of hydrological processes triggering debris flows, namely erosion and transport by intensive overland flow and by infiltrating water causing failure of channel bed material. On the basis of these experiments, an integrated hydro-mechanical model was developed, which describes Hortonian and saturation overland flow, maximum sediment transport, through flow and failure of bed material. The model was calibrated and validated using process indicator values measured during the experiments in the flume. Virtual model simulations carried out in a schematic hypothetical source area of a catchment show that slope angle and hydraulic conductivity of the bed material determine the type and sequence of these triggering processes. It was also clearly demonstrated that the type of hydrological triggering process and the influencing geometrical and hydro-mechanical parameters may have a great influence on rainfall intensity-duration threshold curves for the start of debris flows.

Application of Virtual Environment in the Teaching of Basketball Tactics

The traditional experience basketball teaching method can only master the technical essentials through repeated practice, which seriously affects the ef-ficiency of basketball training. Based on this problem, a basketball teaching simulation system was constructed by using virtual reality technology. The system established a virtual simulation model of basketball players, which planed the track of athletes. In the meanwhile, it captured the real situation of basketball players and contrasted them with simulated trajectories, so as to help athletes do more targeted training. The results showed that basketball technology teaching model based on virtual reality could help athletes grasp the key points of motion skills as soon as possible, and greatly improve the training efficiency of basketball players.

Gathering Validity Evidence for Surgical Simulation: A Systematic Review.

To identify current trends in the use of validity frameworks in surgical simulation, to provide an overview of the evidence behind the assessment of technical skills in all surgical specialties, and to present recommendations and guidelines for future validity studies. Validity evidence for assessment tools used in the evaluation of surgical performance is of paramount importance to ensure valid and reliable assessment of skills. We systematically reviewed the literature by searching 5 databases (PubMed, EMBASE, Web of Science, PsycINFO, and the Cochrane Library) for studies published from January 1, 2008, to July 10, 2017. We included original studies evaluating simulation-based assessments of health professionals in surgical specialties and extracted data on surgical specialty, simulator modality, participant characteristics, and the validity framework used. Data were synthesized qualitatively. We identified 498 studies with a total of 18,312 participants. Publications involving validity assessments in surgical simulation more than doubled from 2008 to 2010 (∼30 studies/year) to 2014 to 2016 (∼70 to 90 studies/year). Only 6.6% of the studies used the recommended contemporary validity framework (Messick). The majority of studies used outdated frameworks such as face validity. Significant differences were identified across surgical specialties. The evaluated assessment tools were mostly inanimate or virtual reality simulation models. An increasing number of studies have gathered validity evidence for simulation-based assessments in surgical specialties, but the use of outdated frameworks remains common. To address the current practice, this paper presents guidelines on how to use the contemporary validity framework when designing validity studies.

Usefulness of the 3D virtual visualization surgical planning simulation and 3D model for endoscopic endonasal transsphenoidal surgery of pituitary adenoma: Technical report and review of literature

Abstract The purpose of this research was to investigate the usefulness of three-dimensional print models (3D models) in endoscopic endonasal transsphenoidal surgery (EeTSS) for pituitary adenoma. Eleven patients underwent EeTSS for pituitary adenoma using 3D models. We manufactured a 3D virtual surgical planning image using the patient's Digital Imaging and Communication in Medicine dataset. Based on the image, a life-size model was created by a 3D printer using multi-material acrylic-based resin. Our results suggest that such 3D models could be useful in EeTSS for pituitary adenoma.

Modeling and Kinematics Simulation of a Mecanum Wheel Platform in RecurDyn

The innovative method of modeling and kinematics simulation in RecurDyn are proposed, taking a Mecanum wheel platform(MWP) for omnidirectional wheelchair as research object. In order to study the motion characteristics and mobile performance of the MWP, the virtual prototype simulation model is established in SolidWorks, and virtual prototype simulation is carried out in RecurDyn. The experience of simulation for the MWP in RecurDyn is introduced, and the simulation steps and points for attention are described detailedly. The working states of the mobile system in real environment have been simulated through virtual simulation experiments. Four typical motion models including moving forward, moving laterally, moving laterally in the direction of 45°, and rotation have been simulated in RecurDyn. The simulation results exactly reflect the motion of the MWP. By comparing the simulation results with the theoretical results, there are acceptable errors that are relatively less overall in the simulation results. The simulation results can be used to predict the performance of the platform and evaluate the design rationality, and design quality can be improved according to the exposed problem. This paper can provide reference for the simulation of mobile platform by using RecurDyn.

Virtual Simulation Analysis of Rigid‐Flexible Coupling Dynamics of Shearer with Clearance

A model for virtual simulation analysis of the rigid‐flexible coupling of a shearer has been developed with the objective of addressing problems associated with lifetime mismatch and low reliability of pin rows of a scraper conveyor and the corresponding support mechanism of a shearer. Simulations were performed using the experimental roller load as stimulus. Results of the analysis demonstrate that the vertical cutting force on the roller serves to reduce the load on the plane support plates during shearer cutting, and the force on the right plane support plate is considerably smaller compared to that on the left plane support plate along the direction of motion of the shearer. Owing to action of the roller‐traction load, loads acting on the two guiding support plates increase significantly along the direction of shearer motion. Mechanical characteristics of the support mechanism were determined through experiments, and the accuracy of the virtual simulation model was verified. Simultaneously, mechanical characteristics of the shearer support mechanism were studied under varying pitch and roll angles. This study was performed to provide a base for analyzing the mechanical characteristics as well as optimizing the structural design of the shearer. Through fatigue‐life analysis of the support plate and subsequent optimization of the support plate structure, the life of the guide support plate was found to have been extended by approximately 1.5 times.

Simulation-Based Development and Validation of Energy Management Concepts

This paper presents a method to support the development of energy management concepts for machine and plant construction. The energy management concepts are required to put the plant components into an energy saving mode during unproductive phases. These concepts then have to be implemented in the control software. Different dependencies in the production and process flow have to be considered when developing the concepts. Due to the complexity of production plants, a supporting simulation tool is planned to be implemented. With the aid of this tool, different energy management concepts and their derived control software can already be validated virtually in the planning and development phase. This presents an energetic extension of the so-called virtual commissioning concept. Conventional virtual commissioning involves only the process operation functionality in a virtual simulation model of the plant. Now, however, energetic functionalities are assigned to the different model components. Thus, a simulation of the energy consumption in different operation modes can be created for each component. Energy management concepts can only be developed if the components’ energy consumption is known in the different scenarios.

Acoustic characterization of the Buddhist temple of Deekshabhoomi in Nagpur, India

This article presents the study of acoustics of the Deekshabhoomi, a Buddhist monument, with an imagery and external form of the Stupa in Nagpur, Maharashtra, India. It is one of the large hollow Buddhist Stupas in the world, with religious activities such as meditation, chanting, and sermons being delivered associated with it. The aim of the research was to assess the acoustical behavior of the space. The research includes in situ measurements at the monument, in an unoccupied condition. The virtual simulation models were then built which were validated with the in situ measurements in the unoccupied condition. These models were further simulated and analyzed for both occupied and unoccupied conditions. The average reverberation time of 5.6 and 9.7 s has been reported at mid-frequencies for occupied and unoccupied conditions, respectively. The article also compares other worship spaces of different religions, like structures with similar nature of the reverberant field, as less research has been done on hollow Buddhist Stupa. It explicates the acoustical condition present in the monument, and its impact on the Buddhist chanting and other religious activities.

Computer Virtual Technology Used in Nc Machine Tool Compensation

This paper presents a comprehensive virtual simulation model for CNC systems. The Virtual CNC (VRCNC) has a modular architecture and the special function. It can show movement process and the result, it can also show the effect of different movement mode, the displacement, velocity and acceleration of the process, the rationality of interpolation method and the motion control method. Additional CNC modules can easily be prototyped and integrated to the VRCNC by the user. Various application examples are presented which include building of physical dynamic control model, the prediction of the displacement, velocity and acceleration of the process, and the process of secant instead of curve. It can show closed loop drive dynamics. Detailed experimental verification is presented for each algorithm.

A Virtual Reality Simulation Model of Spinal Ultrasound: Role in Teaching Spinal Sonoanatomy.

Ultrasound assessment of the lumbar spine improves the success of spinal and epidural anesthesia, especially for patients with underlying difficult anatomy. To assist with the teaching and learning of ultrasound-guided neuraxial anesthesia, we have created an online interactive educational model (http://www.usra.ca/vspine.php and http://pie.med.utoronto.ca/vspine). The aim of the current study was to determine whether the virtual spine model improved the knowledge of neuraxial anatomy and sonoanatomy. After obtaining ethics board approval and written participant consent, 14 anesthesia trainees with no prior experience with spine ultrasound imaging were included in this study. Construct validity was assessed using a pretest/posttest design to measure the knowledge acquired from self-study of the virtual spine simulation modules. Two tests (A and B) with 20 multiple-choice questions were used either for the pretest or posttest, at random in order to account for possible differences in difficulty between the 2 tests. These tests were administered immediately before and after a 1-hour training session using the spine ultrasound model. Fourteen anesthesia trainees completed the study. Seven used test A as the pretest (group A), and 7 used test B as the pretest (group B). Both groups showed a statistically significant improvement (P < 0.05) in test scores after a 1-hour session with the spine ultrasound model. The mean scores were 55% (SD, 11.2%) on the pretest and 77% (SD, 8.7%) on the posttest. The study demonstrated that after 1 hour of self-study by the trainees on the spine ultrasound model test scores improved by 40%.

Virtual Simulation of High Impact Shovel Loading Operation for Optimum Dumping Characterization

The use of large machinery in surface mining operations has resulted in high-impact shovel loading operations (HISLO). When large capacity shovels dump 100+ tons of loads in a single pass, large impact forces are generated resulting in high frequency shock waves. These shock waves cause severe truck vibrations, and thus, expose dump truck operators to high levels of whole body vibrations (WBV) and impact the health and safety of operators. The operator’s lower torso, lower back, legs, feet and hands are exposed to these WBV levels, which ultimately result in lower back injuries, musculoskeletal diseases and other long-term injuries. There exists no fundamental work to address this problem except a rigorous mathematical model for this impact force developed by previous researchers. This paper outlines a pioneering effort to develop a 3D virtual simulation model for a shovel dumping operation using DEM techniques in PFC3D. The model captures material dumping from a P&H 4100XPC shovel into a CAT 793D truck. Analysis of the simulation results showed that a per cent reduction of 4.88, 7.42, 11.45, 12.01, 15.08 and 17.34% can be achieved by reducing the dumping height from 7.33 m to 6.33, 6.00, 5.50, 5.33, 5.00 and 4.9 m, respectively. As a result of the cushioning effect, the reduction in the impact force magnitude ranges between 8.2% and 10.5%. This simulation model can be used to analyse any HISLO operation to reduce or possibly eliminate WBV exposures by optimizing the shovel dumping height to reduce the impact force.

Design of the wind tunnel based virtual flight testing evaluation method for flight control systems

In order to provide a method for evaluating flight control systems with the wind tunnel based virtual flight testing and provide a guide for building virtual flight testing systems, the virtual flight testing evaluation method was researched. The virtual flight testing evaluation method consisted of three parts: virtual flight testing method, virtual flight testing data processing method, and flight control system performance determination method, which were respectively designed for a pitching control system. Then, the hardware-in-the-loop simulation evaluation method was presented, and comparisons between the virtual flight testing and hardware-in-the-loop simulation evaluation method were conducted to highlight the characteristics of virtual flight testing evaluation method. Finally, virtual flight testing simulation models of a sample air vehicle were built and virtual flight testing were simulated to demonstrate the virtual flight testing evaluation method, which is helpful for the understanding of the virtual flight testing evaluation method with more sensibility. The evaluation results show that the virtual flight testing evaluation method designed can be used for flight control system evaluation.

Computer assisted mandibular reconstruction using a custom-made titan mesh tray and removable denture based on the top-down treatment technique

PurposeThe purpose of this report is to propose a computer assisted mandibular reconstruction procedure, utilizing a custom-made Ti-mesh tray with particulate cancellous bone and marrow, and a removable denture. This procedure was based on the top-down treatment technique, and reviews the case of a representative patient with mandibular continuity defect. MethodsThe patient was a 74-year old female with a chief complaint of facial asymmetry and masticatory dysfunction. Due to gingival carcinoma, she underwent a segmental mandibulectomy on the left mandibule.On the VR space, using 3-D reconstructed computer tomography data, the residual right-side mandibular fragment was repositioned based on the condylar position and the occlusal relation. The mandibular fragment was then mirrored for a central sagittal plane. The position of the mirrored object was slightly arranged with the occlusal relation. Through the above operations, the landmark configuration, for the custom-made Ti-mesh tray as a virtual simulation model, was fabricated. On the physical model, we produced a custom-made Ti-mesh tray with a commercial Ti-mesh sheet. Surgical treatment was carried out using the tray.The denture pattern was designed by a dental technician on the VR space, fabricated using a 3D printer, and modified to create an impression tray with resin. Using the impression, the temporary removable denture was fabricated. ConclusionsWe propose a computer assisted design for a custom-made Ti-mesh tray and a removable denture, based on the Top-down treatment concept. We feel this technique is advantageous in reconstructing functional occlusion, and in accurately regaining dental and facial esthetics.

Modeling the Work of a Torque Converter during the Getaway Process of a Vehicle

The paper aims at issuing of a virtual simulation model that would be able to assess the actual working modes of a torque converter, both hydraulically and mechanically. To estimating the dynamic behavior we used the assessing equations of the converter’s performance coefficients. The rotational inertial phenomena due to the transient regimes during the getaway phase are also considered. The modeling process assumed the use of the pre-defined structures of the Simulink-Matlab and Simscape-Matlab modules. The virtual model of the torque converter was fed with the experimentally determined, performance parameters as input. The input also consisted of the inertia moments of the converter’s components. Eventually, by interrogating the simulation model, we’ve got and plotted the time histories of the converter’s impeller and turbine angular velocities during the vehicle’s getaway process.

An interactive system for original necklace design

We propose an interactive system to assist novices in the design and construction of original necklaces. The system consists of two design tools, an interactive drag-and-drop design tool using images of pearls and a design selection tool with an interactive evolutionary computation (IEC) system. The system includes a virtual modeling simulation which allows users to superimpose a necklace design over their own photograph, taken with a web camera. The system also provides a customized construction guide to assist the user with the construction process. We conduct a field trial to demonstrate that non-professional users can design original necklaces using our system.

Effects of the transmission shaft on the main reducer vibration based on ADAMS and experimental demonstration

A variable axial transmission system which is composed of universal joint transmission shafts and a gear pair plays an important role in many engineering fields. However, researchers have done a lot of work in the area of gear dynamic characteristics, seldom considering the effects of universal joint shafts on the modal characteristics of gear pair system. This project takes a rear-wheel drive transmission system as a research subject. A transmission shaft-main reducer assembly virtual prototype simulation model is established by the dynamics software ADAMS; and the effects of the angle between shafts and the intermediate support stiffness on the noise and vibration characteristics of a main reducer in a rear axle are analysed. At the same time, an experiment is conducted to demonstrate the authenticity of the simulation. The result provides reference for parameters design of a drive shaft and a main reducer in a rear axle.