scholarly journals Vibroimpact Mobile Robot

2021 ◽  
Vol 17 (4) ◽  
pp. 429-436
Author(s):  
A. P. Ivanov ◽  
Keyword(s):  
Simple Model ◽  
Mobile Robot ◽  
Periodic Motion ◽  
Horizontal Plane ◽  
Coulomb Friction ◽  
Average Velocity ◽  
Moving Mass ◽  
Harmonic Force ◽  
Maximal Average ◽  
The Right

A simple model of a capsule robot is studied. The device moves upon a rough horizontal plane and consists of a capsule with an embedded motor and an internal moving mass. The motor generates a harmonic force acting on the bodies. Capsule propulsion is achieved by collisions of the inner body with the right wall of the shell. There is Coulomb friction between the capsule and the support, it prevents a possibility of reversal motion. A periodic motion is constructed such that the robot gains the maximal average velocity.

scholarly journals Projection Surfaces Detection and Image Correction for Mobile Robots in HRI

2017 ◽  
Vol 2017 ◽  
pp. 1-16
Author(s):  
Enrique Fernández-Rodicio ◽  
Víctor González-Pacheco ◽  
José Carlos Castillo ◽  
Álvaro Castro-González ◽  
María Malfaz ◽  
...  
Keyword(s):  
Mobile Robot ◽  
Vertical Plane ◽  
Vertical Surface ◽  
Human Robot Interaction ◽  
Image Correction ◽  
Robot Interaction ◽  
Kinect Camera ◽  
Fitting Algorithm ◽  
The Right ◽  
Large Groups

Projectors have become a widespread tool to share information in Human-Robot Interaction with large groups of people in a comfortable way. Finding a suitable vertical surface becomes a problem when the projector changes positions when a mobile robot is looking for suitable surfaces to project. Two problems must be addressed to achieve a correct undistorted image: (i) finding the biggest suitable surface free from obstacles and (ii) adapting the output image to correct the distortion due to the angle between the robot and a nonorthogonal surface. We propose a RANSAC-based method that detects a vertical plane inside a point cloud. Then, inside this plane, we apply a rectangle-fitting algorithm over the region in which the projector can work. Finally, the algorithm checks the surface looking for imperfections and occlusions and transforms the original image using a homography matrix to display it over the area detected. The proposed solution can detect projection areas in real-time using a single Kinect camera, which makes it suitable for applications where a robot interacts with other people in unknown environments. Our Projection Surfaces Detector and the Image Correction module allow a mobile robot to find the right surface and display images without deformation, improving its ability to interact with people.

Dynamic Instability in Quartering Seas—Part III: Nonlinear Effects on Periodic Motions

1997 ◽  
Vol 41 (03) ◽  
pp. 210-223 ◽  
Author(s):  
K. J. Spyrou
Keyword(s):  
Periodic Motion ◽  
Horizontal Plane ◽  
Dynamic Instability ◽  
Parametric Instability ◽  
Nonlinear Effects ◽  
Ship Motions ◽  
Nonlinear Phenomena ◽  
Specific Sequence ◽  
The Stability ◽  
Two Stages

The loss of stability of the horizontal-plane periodic motion of a steered ship in waves is investigated. In earlier reports we referred to the possibility of a broaching mechanism that will be intrinsic to the periodic mode, whereby there will exist no need for the ship to go through the surf-riding stage. However, about this point the discussion was essentially conjectural. In order to provide substance we present here a theoretical approach that is organized in two stages: Initially, we demonstrate the existence of a mechanism of parametric instability of yaw on the basis of a rudimentary, single-degree model of maneuvering motion in waves. Then, with a more elaborate model, we identify the underlying nonlinear phenomena that govern the large-amplitude horizontal ship motions, considering the ship as a multi-degree, nonlinear oscillator. Our analysis brings to light a very specific sequence of phenomena leading to cumulative broaching that involves a change in the stability of the ordinary periodic motion on the horizontal plane, a transition towards subharmonic response and, ultimately, a sudden jump to resonance. Possible means for controlling the onset of such undesirable behavior are also investigated.

SMALL-ANGLE SCATTERING OF FAST POLARIZED NEUTRONS BY HEAVY NUCLEI

1956 ◽  
Vol 34 (1) ◽  
pp. 36-42 ◽  
Author(s):  
J. T. Sample
Keyword(s):  
Small Angle ◽  
Intensity Ratio ◽  
Horizontal Plane ◽  
Small Angle Scattering ◽  
Fast Neutrons ◽  
Heavy Nuclei ◽  
Spin Orientation ◽  
Scattering Angle ◽  
Angle Scattering ◽  
The Right

Detailed calculations have been carried out which indicate that the small-angle scattering of fast neutrons by lead depends on the polarization, or spin orientation, of the neutrons. When the scattering of neutrons whose spin vectors point upward is observed in the horizontal plane, more neutrons should be found scattered to the right than to the left. For completely polarized 3.1 Mev. neutrons, the theory predicts a maximum "right to left" intensity ratio of 14.5:1 at a scattering angle of 0.5°, the ratio decreasing to 1.6:1 at 5°, and approaching unity rapidly as the scattering angle increases.

scholarly journals A Comparative study to measure the horizontal condylar guidance obtained by protrusive interocclusal records and panoramic radiographic images in completely edentulous patients

2018 ◽  
Vol 14 (1) ◽  
pp. 21-27
Author(s):  
Arjun Bhandari ◽  
Archana Manandhar ◽  
Raj Kumar Singh ◽  
Pramita Suwal ◽  
Prakash Kumar Parajuli
Keyword(s):  
Zinc Oxide ◽  
Horizontal Plane ◽  
Significant Positive Correlation ◽  
Panoramic Radiograph ◽  
Articular Eminence ◽  
Radiographic Images ◽  
The Mean ◽  
Edentulous Patients ◽  
The Right ◽  
Interocclusal Records

Background & Objectives:The study was conducted with objective to compare the horizontal condylar guidance (HCG) obtained by protrusive interocclusal records and panoramic radiographic images in completely edentulous patients.Materials & Methods:The horizontal condylar guidance was measured in 25 completely edentulous patients by protrusive interocclusal records using zinc oxide eugenol paste through a face bow transfer (HanauTM Spring bow, Whip Mix Corporation, USA) to a semi-adjustable articulator (HanauTM Wide-Vue Articulator, Whip Mix Corporation, USA).  In the same patients, HCG was traced in the panoramic radiograph. The angles formed by the intersection of two lines: Frankfurt’s horizontal plane and posterior slope of articular eminence was measured using protractor to represent the horizontal condylar guidance angle on each side.Results:The mean difference between the horizontal condylar guidance angles values obtained using protrusive interocclusal record and panoramic radiograph was 2.68 degrees and 3.40 degrees for the right and the left side respectively, with the panoramic radiograph values being higher. This difference between the values was found to be highly significant between the two methods for the right side (t = 2.70, p = 0.012) and left side (t = 3.69, p = 0.001). A significant positive correlation was found between the horizontal condylar guidance obtained from protrusive interocclusal record and panoramic radiograph for the right (r = 0.643, p = 0.001) and left sides (r = 0.622, p = 0.001) separately.Conclusion:The panoramic radiographic tracing can be used to calculate the mean horizontal condylar guidance in the completely edentulous patients and these values can be used to programme semi-adjustable articulators avoiding the cumbersome process of obtaining protrusive interocclusal records.

Histopathology of Acquired Subglottic Stenosis

1981 ◽  
Vol 90 (4) ◽  
pp. 335-338 ◽  
Author(s):  
Gabriel F. Tucker ◽  
Leonard Newton ◽  
Robert J. Ruben
Keyword(s):  
Endotracheal Tube ◽  
Horizontal Plane ◽  
Cricoid Cartilage ◽  
Subglottic Stenosis ◽  
Total Occlusion ◽  
History Of ◽  
The Right ◽  
Stenotic Area

The history of a 2,900 g infant who had no stridor at birth and developed subglottic stenosis is presented in detail. The laryngeal lumen, which accepted a 3 mm endotracheal tube at one day of age, diminished to total occlusion at 15 months of age. There was an 8-day intubation and tracheotomy at nine months. At 19 months the patient expired from associated cardiac problems; the larynx was obtained at autopsy and was serially sectioned in the horizontal plane. A series (1mm-Tracer) of 12 sections through the stenotic area is presented. It demonstrates gross distortion of the cricoid cartilage with ossification extending into the right paraglottic larynx.

scholarly journals Perception of combined translation and rotation in the horizontal plane in humans

2016 ◽  
Vol 116 (3) ◽  
pp. 1275-1285 ◽  
Author(s):  
Benjamin T. Crane
Keyword(s):  
Motion Perception ◽  
Horizontal Plane ◽  
Peak Velocity ◽  
Human Subjects ◽  
Human Motion ◽  
Subjective Equality ◽  
The Right ◽  
Biased Perception

Thresholds and biases of human motion perception were determined for yaw rotation and sway (left-right) and surge (fore-aft) translation, independently and in combination. Stimuli were 1 Hz sinusoid in acceleration with a peak velocity of 14°/s or cm/s. Test stimuli were adjusted based on prior responses, whereas the distracting stimulus was constant. Seventeen human subjects between the ages of 20 and 83 completed the experiments and were divided into 2 groups: younger and older than 50. Both sway and surge translation thresholds significantly increased when combined with yaw rotation. Rotation thresholds were not significantly increased by the presence of translation. The presence of a yaw distractor significantly biased perception of sway translation, such that during 14°/s leftward rotation, the point of subjective equality (PSE) occurred with sway of 3.2 ± 0.7 (mean ± SE) cm/s to the right. Likewise, during 14°/s rightward motion, the PSE was with sway of 2.9 ± 0.7 cm/s to the left. A sway distractor did not bias rotation perception. When subjects were asked to report the direction of translation while varying the axis of yaw rotation, the PSE at which translation was equally likely to be perceived in either direction was 29 ± 11 cm anterior to the midline. These results demonstrated that rotation biased translation perception, such that it is minimized when rotating about an axis anterior to the head. Since the combination of translation and rotation during ambulation is consistent with an axis anterior to the head, this may reflect a mechanism by which movements outside the pattern that occurs during ambulation are perceived.

Estimating Ricochet Hazard Zones at Sea

2018 ◽  
Vol 15 (4) ◽  
pp. 399-413
Author(s):  
Ramzi Mirshak ◽  
Talia Beech
Keyword(s):  
Simple Model ◽  
Ocean Waves ◽  
Considerable Effect ◽  
Controlled Experiments ◽  
Risk Area ◽  
Wave Fields ◽  
Considerable Uncertainty ◽  
Hazard Zone ◽  
The Right ◽  
Two Degree Of Freedom

Naval operators commonly report that when projectiles impact the ocean surface, they ricochet mainly to the right but that some rounds ricochet in wildly unpredictable directions. This observation, which leads to considerable uncertainty with regard to the resulting hazard zone for projectiles fired at sea, seems contradictory to observations from controlled experiments where projectiles with similar incident angles tend to ricochet in a more predictable manner. In this paper, we postulate that the likely cause of the discrepancy is ocean waves. Past work examining the effect of waves on ricochet is extended to model the risk area related to projectile ricochet at sea. Ricochet results from controlled experiments are incorporated into a simple model that combines a two-degree-of-freedom ballistic model and a series of analytically derived wave fields with different amplitudes and directions of travel. For the purposes of demonstration in this paper, data for different .50 calibre projectiles are used to populate the model. The results support the notion that waves have a considerable effect on ricochet hazard zones.

Contribution of auditory cortex to sound localization by the ferret (Mustela putorius)

1987 ◽  
Vol 57 (6) ◽  
pp. 1746-1766 ◽  
Author(s):  
G. L. Kavanagh ◽  
J. B. Kelly
Keyword(s):  
Auditory Cortex ◽  
Sound Localization ◽  
Horizontal Plane ◽  
Primary Auditory Cortex ◽  
Cortical Lesions ◽  
Mustela Putorius ◽  
Complete Destruction ◽  
Left And Right ◽  
The Right ◽  
Bilateral Lesions

Ferrets were tested in a semicircular apparatus to determine the effects of auditory cortical lesions on their ability to localize sounds in space. They were trained to initiate trials while facing forward in the apparatus, and sounds were presented from one of two loudspeakers located in the horizontal plane. Minimum audible angles were obtained for three different positions, viz., the left hemifield, with loudspeakers centered around -60 degrees azimuth; the right hemifield, with loudspeakers centered around +60 degrees azimuth; and the midline with loudspeakers centered around 0 degrees azimuth. Animals with large bilateral lesions had severe impairments in localizing a single click in the midline test. Following complete destruction of the auditory cortex performance was only marginally above the level expected by chance even at large angles of speaker separation. Severe impairments were also found in localization of single clicks in both left and right lateral fields. In contrast, bilateral lesions restricted to the primary auditory cortex resulted in minimal impairments in midline localization. The same lesions, however, produced severe impairments in localization of single clicks in both left and right lateral fields. Large unilateral lesions that destroyed auditory cortex in one hemisphere resulted in an inability to localize single clicks in the contralateral hemifield. In contrast, no impairments were found in the midline test or in the ipsilateral hemifield. Unilateral lesions of the primary auditory cortex resulted in severe contralateral field deficits equivalent to those seen following complete unilateral destruction of auditory cortex. No deficits were seen in either the midline or the ipsilateral tests.

Design of a Freeway Mathematical Model and its Performance Analysis

2014 ◽  
Vol 971-973 ◽  
pp. 2321-2324
Author(s):  
Li Qing Zhou ◽  
Ke Wang ◽  
Da Xu
Keyword(s):  
Mathematical Model ◽  
Performance Analysis ◽  
Traffic Flow ◽  
Safety Factor ◽  
Average Velocity ◽  
Traffic Conditions ◽  
Long Time ◽  
Function Relationship ◽  
The Right

Although driving automobiles on the right rule has existed for a long time, few people understand the reason why we set it. For these problems, we develop a model to evaluate this rule’s effect in different traffic conditions and to find the relations between vehicle’s density, traffic flow, safety factor and average velocity. The first model puts forward a mathematic method to establish function relationship between these parameters and try to solve out a quantifiable result. The conclusion will be beneficial for easing the traffic pressure, and figure out whether this rule is scientific or can be replaced by another better role.

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