scholarly journals Accelerometry-Enhanced Magnetic Sensor for Intra-Oral Continuous Jaw Motion Tracking

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1409
Author(s):  
Mantas Jucevičius ◽  
Rimantas Ožiūnas ◽  
Mindaugas Mažeika ◽  
Vaidotas Marozas ◽  
Darius Jegelevičius
Keyword(s):  
Degrees Of Freedom ◽  
Motion Tracking ◽  
3D Models ◽  
Movement Trajectories ◽  
Impact Detection ◽  
Occlusal Splints ◽  
Motion Simulator ◽  
Controlled Environments ◽  
New Research ◽  
Jaw Position

Currently available jaw motion tracking methods require large accessories mounted on a patient and are utilized in controlled environments, for short-time examinations only. In some cases, especially in the evaluation of bruxism, a non-restrictive, 24-h jaw tracking method is needed. Bruxism oriented, electromyography (EMG)-based devices and sensor-enhanced occlusal splints are able to continuously detect masticatory activity but are uninformative in regards to movement trajectories and kinematics. This study explores a possibility to use a permanent magnet and a 3-axial magnetometer to track the mandible’s spatial position in relation to the maxilla. An algorithm for determining the sensor’s coordinates from magnetic field values was developed, and it was verified via analytical and finite element modeling and by using a 3D positioning system. Coordinates of the cubic test trajectory (a = 10 mm) were determined with root-mean-square error (RMSE) of 0.328±0.005 mm. Possibility for teeth impact detection by accelerometry was verified. Test on a 6 degrees-of-freedom (DOF), hexapod-based jaw motion simulator moving at natural speed confirmed the system’s ability to simultaneously detect jaw position and the impacts of teeth. Small size of MEMS sensors is suitable for a wearable intra-oral system that could allow visualization of continuous jaw movement in 3D models and could enable new research on parafunctional jaw activities.

Maximum Total Point Motion of Five Points Versus All Points in Assessing Tibial Baseplate Stability

2021 ◽  
Author(s):  
Abigail Niesen ◽  
Anna L Garverick ◽  
Maury Hull
Keyword(s):  
Degrees Of Freedom ◽  
Stability Limit ◽  
3D Models ◽  
Six Degrees Of Freedom ◽  
Percent Error ◽  
Model Based ◽  
Point Motion ◽  
The Mean ◽  
The Difference ◽  
Total Point

Abstract Maximum total point motion (MTPM), the point on a baseplate that migrates the most, has been used to assess the risk of tibial baseplate loosening using radiostereometric analysis (RSA). Two methods for determining MTPM for model-based RSA are to use either 5 points distributed around the perimeter of the baseplate or to use all points on the 3D model. The objectives were to quantify the mean difference in MTPM using 5 points vs. all points, compute the percent error relative to the 6-month stability limit for groups of patients, and to determine the dependency of differences in MTPM on baseplate size and shape. A dataset of 10,000 migration values was generated using the mean and standard deviation of migration in six degrees of freedom at 6 months from an RSA study. The dataset was used to simulate migration of 3D models (two baseplate shapes and two baseplate sizes) and calculate the difference in MTPM using 5 virtual points vs. all points and the percent error (i.e. difference in MTPM/stability limit) relative to the 6-month stability limit. The difference in MTPM was about 0.02 mm, or 4% percent relative to the 6-month stability limit, which is not clinically important. Furthermore, results were not affected by baseplate shape or size. Researchers can decide whether to use 5 points or all points when computing MTPM for model-based RSA. The authors recommend using 5 points to maintain consistency with marker-based RSA.

scholarly journals Design Techniques for Elliptical Micro-Strip Patch Antenna and Their Effects on Antenna Performance

2019 ◽  
Vol 8 (12) ◽  
pp. 2317-2326
Keyword(s):  
Patch Antenna ◽  
Degrees Of Freedom ◽  
Wide Band ◽  
Research Area ◽  
Patch Antennas ◽  
Bandwidth Enhancement ◽  
Antenna Performance ◽  
Elliptical Ring ◽  
New Research ◽  
Design Techniques

Elliptical Micro-strip Patch Antenna (EMPA) has been emerged as a peculiar and significant category among the different shaped micro-strip patch antennas because of its circular polarization and dual-resonant frequency features with a single feed. Elliptical and its derived shapes such as semielliptical, half-elliptical, slotted-elliptical and elliptical ring are found to be particularly instrumental for bandwidth enhancement and these antennas find great applications in Ultra Wide Band (UWB) and Super Wide Band (SWB) communications. Compared to antennas with circular or rectangular shapes, the design of EMPA is a research area of high potential as there is higher flexibility in its design due to more degrees of freedom. The reported literature in the field of EMPA is very less and there is ample scope for new researchers to work on. This review paper is an attempt to summarize and critically assess the-state-of-the-art design techniques as reported in literature and understand their effects on performance of elliptical patch antenna for suggesting new research fronts in the field of EMPA.

Structural Analysis of Riveted Structures Using a New FE Modelling Technique

2010 ◽  
Author(s):  
Michele Ferracci ◽  
Francesco Vivio ◽  
Vincenzo Vullo
Keyword(s):  
Degrees Of Freedom ◽  
Complex Structure ◽  
Element Model ◽  
3D Models ◽  
Fatigue Behaviour ◽  
Fe Analysis ◽  
Structural Behaviour ◽  
Fe Modelling ◽  
Closed Form Solutions ◽  
Riveted Joints

A theoretical approach, in order to define the structural behaviour of riveted joints, is presented. The closed form solutions lead to the definition of a Rivet Element useful to FE models of multi-riveted structures. The objective is an accurate evaluation of the local stiffness of riveted joints in FE analysis, which is fundamental to perform a reliable simulation of multi-joint structures and, consequently, a good estimate of loads acting on connections; this makes it possible to introduce new general criteria allowing, for example, to predict fatigue behaviour. On the other hand, a low number of degrees of freedom is needed when several connections are present in a complex structure. The goal is to reach a reliable model of the rivet region which can be used as the basis to develop a Rivet Element in FE analysis. The proposed Rivet Element combines the precision in the simulation with a very limited number degrees of freedom in the finite element model of a complex structure having several rivets. In the present paper the structural behavior of two simple riveted specimens is investigated experimentally and numerically using a new Rivet Element. A comparison with a joint model performed with very refined non-linear 3D models of rivet and with experimental data is performed and a good agreement is shown.

Control System for an Elbow Joint Motion Simulator

2007 ◽  
Author(s):  
Patrick J. Schimoler ◽  
Jeffrey S. Vipperman ◽  
Laurel Kuxhaus ◽  
Angela M. Flamm ◽  
Daniel D. Budny ◽  
...  
Keyword(s):  
Control System ◽  
Elbow Joint ◽  
Degrees Of Freedom ◽  
Biceps Brachii ◽  
Control Algorithms ◽  
Joint Motion ◽  
Motion Simulator ◽  
Co Activation ◽  
Flexion Extension ◽  
The Many

The many muscles crossing the elbow joint allow for its motions to be created from different combinations of muscular activations. Muscles are strictly contractile elements and the joints they surround rely on varying loads from opposing antagonists for stability and movement. In designing a control system to actuate an elbow in a realistic manner, unidirectional, tendon-like actuation and muscle co-activation must be considered in order to successfully control the elbow’s two degrees of freedom. Also important is the multifunctionality of certain muscles, such as the biceps brachii, which create moments impacting both degrees of freedom: flexion / extension and pronation / supination. This paper seeks to develop and implement control algorithms on an elbow joint motion simulator that actuates cadaveric elbow specimens via four major muscles that cross the elbow joint. The algorithms were validated using an anatomically-realistic mechanical elbow. Clinically-meaningful results, such as the evaluation of radial head implants, can only be obtained under repeatable, realistic conditions; therefore, physiologic motions must be created by the application of appropriate loads. This is achieved by including load control on the muscles’ actuators as well as displacement control on both flexion / extension and supination / pronation.

Development of a Human Factors Research Laboratory for Off-Road Vehicle Operator Workstation Design

1982 ◽  
Vol 26 (10) ◽  
pp. 896-900 ◽  
Author(s):  
J. R. Duncan ◽  
E. L. Wegscheid
Keyword(s):  
Human Factors ◽  
Research Laboratory ◽  
Degrees Of Freedom ◽  
Human Performance ◽  
Computer Control ◽  
Road Vehicle ◽  
Motion Simulator ◽  
Vehicle Motion ◽  
Simulator Motion ◽  
Human Factors Research

A new human factors research laboratory has been developed to provide reliable human-performance data for the design of improved off-road vehicle operator workstations. The principal research tool within this laboratory is a vehicle operations simulator. The simulator consists of a hydraulically driven platform upon which a vehicle operator's enclosure or workstation can be mounted. Under computer control, the simulator is capable of motion with six degrees-of-freedom. With this capability, the simulator's motion can be programmed to reproduce operator workstation vibration experienced in operational field environments. Both field recorded data and mathematical simulations of existing and proposed vehicles can be used to command the simulator motion. In addition to simulating vehicle motion, the simulator is capable of producing realistic control and monitoring tasks for the operator, as well as operator enclosure environmental conditions. This paper describes the research objectives for which the simulator was built, the specifications used in the design of the vehicle motion simulator system, the hardware selected in implementing that design, and the computer control used to simulate both field and artificial “ride” histories.

Consistent Mesh Segmentation Based on Shape Diameter Function and EM

2014 ◽  
Vol 1049-1050 ◽  
pp. 1417-1420
Author(s):  
Hui Jia ◽  
Guo Hua Geng ◽  
Jian Gang Zhang
Keyword(s):  
Computer Graphics ◽  
3D Model ◽  
Shape Function ◽  
3D Models ◽  
Gaussian Mixture ◽  
Mesh Segmentation ◽  
Shape Similarity ◽  
Research Focus ◽  
Model Segmentation ◽  
New Research

3D model segmentation is a new research focus in the field of computer graphics. The segmentation algorithm of this paper is consistent segmentation which is about a group of 3D model with shape similarity. A volume-based shape-function called the shape diameter function (SDF) is used to on behalf of the characteristics of the model. Gaussian mixture model (GMM) is fitting k Gaussians to the SDF values, and EM algorithm is used to segment 3D models consistently. The experimental results show that this algorithm can effectively segment the 3D models consistently.

scholarly journals HUMANOID LOCOMOTION MANIPULATED USING DYNAMIC FINGER GESTURES

2013 ◽  
pp. 170-173
Author(s):  
HARI KRISHNAN R ◽  
VALLIKANNU A. L
Keyword(s):  
Human Computer Interaction ◽  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Human Robot Interaction ◽  
Robot Interaction ◽  
Hand Motion ◽  
Computer Interaction

The fundamental technologies for Human-Computer Interaction are Hand motion tracking and Gesture Identification. The same technology has been adapted for Human-Robot Interaction. This paper discusses a natural methodology for Human-Robot Interaction. In the proposed system, the accelerometers at the fingers, tracks specific gestures. These gestures are identified by the controller, which in turn controls the actuators that results in Humanoid walking. The Humanoid under consideration has 8 Degrees of Freedom.

Experiments on Linear and Nonlinear Control of a Multi-DOF Parallel Mechanism

2003 ◽  
Author(s):  
Sandor Riebe ◽  
Heinz Ulbrich
Keyword(s):  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Parallel Robot ◽  
Parallel Kinematics ◽  
Control Laws ◽  
Six Degrees Of Freedom ◽  
Position Accuracy ◽  
Nonlinear Approach ◽  
Linear Approach ◽  
Measurement Results

Parallel kinematics with multi degrees-of-freedom (DOF), like hexapod-systems, are mostly used in applications where high demands on position accuracy are required and/or high accelerations are needed. Adequate control concepts are essential in order to achieve the desired dynamic response. This paper deals with a comparative study of two structural different control concepts applied on a parallel robot with six degrees-of-freedom. The first one is a decentral linear approach and the second one is a multivariable nonlinear approach. The two concepts are presented and implemented on an experimental hexapod-system. In order to verify the used dynamic model comparisons between simulation and measurement results are shown. Finally, experiments have been carried out to compare the control laws with respect to their motion tracking performance.

scholarly journals Studies Evaluating Measurement Accuracy of CMS-JAW, a Jaw Motion Tracking Device with Six Degrees of Freedom Using an Ultrasonic Recording System

2008 ◽  
Vol 52 (3) ◽  
pp. 350-359 ◽  
Author(s):  
Takashi Uchida ◽  
Jun Sakai ◽  
Yasuhiro Okamoto ◽  
Tsukasa Watanabe ◽  
Tsuyoshi Kitagawa ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Measurement Accuracy ◽  
Recording System ◽  
Six Degrees Of Freedom ◽  
Tracking Device
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