Proposal of Criteria Characterizing Assembly Operations of Flexible Beam Parts for Virtual Reality Applications

2004 ◽  
Author(s):  
A. Mikchevitch ◽  
J.-C. Le´on ◽  
A. Gouskov
Keyword(s):  
Tracking System ◽  
Optical Tracking ◽  
Physical Parameters ◽  
Flexible Beam ◽  
Optical Tracking System ◽  
Flexible Parts ◽  
Quality Of Products ◽  
Assembly Operations ◽  
Realistic Data

Fast simulation of Assembly/Disassembly (A/D) operations is important to improve quickly the performance and quality of products. However, it is difficult to model accurately the A/D operations of products containing flexible parts given their complex mechanical behavior. To evaluate the A/D of flexible parts in order to provide better responses in terms of design, maintenance, ergonomics, a user needs criteria characterizing A/D operations. The aim of this work is to propose some of these criteria based on geometric and physical parameters. The realistic values of these parameters are coupled to an adequate behavior model of flexible parts and can be used in virtual A/D simulations. So, as an issue of current A/D approach problems, the requirements for integration of the Interactive Mechanical Model (IMM) into a virtual A/D system are discussed. An example of flexible beam IMM providing the realistic data is presented. The use of non-linear IMMs raises questions regarding the boundary conditions required to model a user’s action during a virtual A/D operation simulation. To this end, physical and numerical experiments have been performed using an optical tracking system. From these experiments, the necessary parameters can be extracted to characterize both real and virtual A/D operations.

scholarly journals In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

2021 ◽  
Vol 11 (9) ◽  
pp. 3947
Author(s):  
Marco Farronato ◽  
Gianluca M. Tartaglia ◽  
Cinzia Maspero ◽  
Luigi M. Gallo ◽  
Vera Colombo
Keyword(s):  
Measurement Error ◽  
Tracking System ◽  
Intraclass Correlation ◽  
Optical Tracking ◽  
Optical Tracking System ◽  
Rater Reliability ◽  
Tracking Device ◽  
Mandibular Kinematics

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.

scholarly journals High Precision Optical Tracking System Based on near Infrared Trinocular Stereo Vision

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2528
Author(s):  
Songlin Bi ◽  
Yonggang Gu ◽  
Jiaqi Zou ◽  
Lianpo Wang ◽  
Chao Zhai ◽  
...  
Keyword(s):  
High Precision ◽  
Stereo Vision ◽  
Near Infrared ◽  
Nearest Neighbor ◽  
Tracking System ◽  
Optical Tracking ◽  
Tracking Accuracy ◽  
Optical Tracking System ◽  
Dynamic Tracking ◽  
Trinocular Stereo

A high precision optical tracking system (OTS) based on near infrared (NIR) trinocular stereo vision (TSV) is presented in this paper. Compared with the traditional OTS on the basis of binocular stereo vision (BSV), hardware and software are improved. In the hardware aspect, a NIR TSV platform is built, and a new active tool is designed. Imaging markers of the tool are uniform and complete with large measurement angle (>60°). In the software aspect, the deployment of extra camera brings high computational complexity. To reduce the computational burden, a fast nearest neighbor feature point extraction algorithm (FNNF) is proposed. The proposed method increases the speed of feature points extraction by hundreds of times over the traditional pixel-by-pixel searching method. The modified NIR multi-camera calibration method and 3D reconstruction algorithm further improve the tracking accuracy. Experimental results show that the calibration accuracy of the NIR camera can reach 0.02%, positioning accuracy of markers can reach 0.0240 mm, and dynamic tracking accuracy can reach 0.0938 mm. OTS can be adopted in high-precision dynamic tracking.

scholarly journals Skill Transference of a Probe-Tube Placement Training Simulator

2020 ◽  
Vol 31 (01) ◽  
pp. 040-049 ◽  
Author(s):  
Robert W. Koch ◽  
Hasan Saleh ◽  
Paula Folkeard ◽  
Sheila Moodie ◽  
Conner Janeteas ◽  
...  
Keyword(s):  
Mixed Model ◽  
Tracking System ◽  
Optical Tracking ◽  
Tube Placement ◽  
Control Group ◽  
Educational Settings ◽  
Training Simulator ◽  
Nonlinear Mixed Model ◽  
Optical Tracking System ◽  
Clinical Scenarios

AbstractProbe-tube placement is a necessary step in hearing aid verification which needs ample hands-on experience and confidence before performing in clinic. To improve the methods of training in probe-tube placement, a manikin-based training simulator was developed consisting of a 3D-printed head, a flexible silicone ear, and a mounted optical tracking system. The system is designed to provide feedback to the user on the depth and orientation of the probe tube, and the time required to finish the task. Although a previous validation study was performed to determine its realism and teachability with experts, further validation is required before implementation into educational settings.This study aimed to examine the skill transference of a newly updated probe-tube placement training simulator to determine if skills learned on this simulator successfully translate to clinical scenarios.All participants underwent a pretest in which they were evaluated while performing a probe-tube placement and real-ear-to-coupler difference (RECD) measurement on a volunteer. Participants were randomized into one of two groups: the simulator group or the control group. During a two-week training period, all participants practiced their probe-tube placement according to their randomly assigned group. After two weeks, each participant completed a probe-tube placement on the same volunteer as a posttest scenario.Twenty-five novice graduate-level student clinicians.Participants completed a self-efficacy questionnaire and an expert observer completed a questionnaire evaluating each participant’s performance during the pre- and posttest sessions. RECD measurements were taken after placing the probe tube and foam tip in the volunteer’s ear. Questionnaire results were analyzed through nonparametric t-tests and analysis of variance, whereas RECD results were analyzed using a nonlinear mixed model method.Results suggested students in the simulator group were less likely to contact the tympanic membrane when placing a probe tube, appeared more confident, and had better use of the occluding foam tip, resulting in more improved RECD measurements.The improved outcomes for trainees in the simulator group suggest that supplementing traditional training with the simulator provides useful benefits for the trainees, thereby encouraging its usage and implementation in educational settings.

Planning Method for Safety Neurosurgical and Computed Tomography Contrast-Data Set Visualization

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Husham Farouk Ismail Saied
Keyword(s):  
Computed Tomography ◽  
Tracking System ◽  
Optical Tracking ◽  
Planning System ◽  
Surgical Instrument ◽  
Optical Tracking System ◽  
Data Set ◽  
Strict Adherence ◽  
Surgical Access ◽  
The Brain

Discussed the issues' associated with the development of a computed neurosurgery planning system. An important part is to determine the value of invasive surgical access. The study purpose is to design a methodology for finding the shortest distance between surgical target and peripheral point of the brain tissue with strict adherence considering the type of the brain anatomical structure existing in the path of surgical track (risk map), these two condition used in companion to determine the risk value of the surgical access. The study method consists of two algorithms for calculating the shortest surgical access to the target and assuring the safety by avoiding high-density tissues identification method “internal map” describing the anatomy of the brain such as bones. An algorithm for automatic identification of brain vascular system also was designed. The structural diagram of the contrast data visualization system, using computed tomography data, was thoroughly discussed. Also, trying to contribute in solving issues facing developers of modern medical imaging visualization systems to select the most appropriate method from the whole arsenal of algorithms and processing models concerning displaying brain surgical zone using image registration and optical tracking system. The visualization of the target zone is carried out according to an internal reference landmark points inside the center of the brain as well as an automatic algorithm for contour recognition was applied. Moreover, the optical tracking system was used to assess the navigation accuracy of determining the position of the surgical instrument outside the patient head. Algorithms necessary for operational planning also was included, and the proposed method was applied in a pilot study with simulation mode to human brain model, in order to target a specific surgical zone, and as a result, the system suggested (24) possible surgical track, among them, were selected the best and safest access. The total error of a surgical instrument targeting was less than 3 mm (in average 2.6 mm).

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