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363 results on '"multiple degrees of freedom"'

351. On Sub-Harmonic and'Summed and Differential Harmonic'Oscillations of Rotating Shaft

Author

Toshio Yamamoto

Subjects
Physics, Vibration, Multiple degrees of freedom, Critical speed, Classical mechanics, Oscillation, Spring (device), General Engineering, Harmonic (mathematics), Differential (infinitesimal), Type (model theory)
Abstract

The author has found experimentally that sub-harmonic oscillations and "summed and differential harmonic"oscillations take place in a shaft system with non-linear spring characteristics and multiple degrees of freedom. In the present paper, these vibrations are treated mathematically and analytically. Conclusions arrived at may be summarized as follows : (1) The equation of response curves of sub-harmonic oscillations of order 1/2 has qualitatively the same construction as that of rectilinear vibratory system. The hard or soft spring characteristics result in response curves of both hard and soft spring types. (2) When two vibrations taking place at the critical speed of "summed and differential harmonic"oscillations are both forward or both backward precessional whirling motions, only the summed harmonic type can occur and the differential type does not take place. When "summed and differential harmonic"oscillation consists of forward and backward precessional motions, only differential type has possibility of occurrence.

Published
1961

352. On the Critical Speeds with Peculiar Modes of Vibration

Author

Toshio Yamamoto

Subjects
Vibration, Multiple degrees of freedom, Physics, Critical speed, Normal mode, Spring (device), Oscillation, medicine, Stiffness, Absolute value, Mechanics, medicine.symptom
Abstract

When single-row radial ball bearings are used the stiffness of a shaft has non-symmetrical, non-linear spring charactristics. In experiments using such a shaft mounting one disc, several critical speeds of peculiar modes of vibration occurred with a critical speed of sub-harmonic oscillation of order 1/2. These critical speeds consist of two vibrations having the same frequencies pi and pj as the natural frequencies of this system. It is remarkable that the absolute value of sum of or difference in two frequencies pi and pj is equal to the rotating speed of the shaft. In numerous experiments with several kinds of shafts, this relation between pi and pj always held at these critical speeds. For a system having linear spring characteristics or a system with one degree of freedom, this type of critical speed does not appear ; it occurs only in the system with multiple degrees of freedom and non-linearity.

Published
1956

353. Analýza chování modelu vibračního generátoru s více stupni volnosti

Author

Hadaš, Zdeněk, Rubeš, Ondřej, Witassek, Tomáš, Hadaš, Zdeněk, Rubeš, Ondřej, and Witassek, Tomáš

Abstract

Na začátku této bakalářské práce je rešerše vibračních generátorů s více stupni volnosti. V rešerši jsou uvedeny různé možnosti rozšíření užitečného frekvenčního pásma pomocí zvýšení stupňů volnosti. Dále je analyzováno chování jednoho vibračního generátoru se sinusovým buzením a jednoho s reálným buzením s využítím počítačového modelu v Matlab & Simulink. Především je kladen důraz na výstupní elektrický výkon a energii v závislosti na různých geometrických parametrech a elektromagnetickém tlumení., The first part of this bachelor’s thesis is an overview of vibration energy harversters with multiple degrees of freedom. Several options of broadening the usefull frequency bandwidth thanks to multiple degrees of freedom are described in the overview. The following part is a model in Matlab & Simulink analyzing behaviour of a vibration-powered generator with a harmonic excitation and another one with a real excitation. The main focus is on the output electrical power and energy in relation to geometrical parameters and electromagnetic damping.

354. Analýza chování modelu vibračního generátoru s více stupni volnosti

Author

Hadaš, Zdeněk, Rubeš, Ondřej, Witassek, Tomáš, Hadaš, Zdeněk, Rubeš, Ondřej, and Witassek, Tomáš

Abstract

Na začátku této bakalářské práce je rešerše vibračních generátorů s více stupni volnosti. V rešerši jsou uvedeny různé možnosti rozšíření užitečného frekvenčního pásma pomocí zvýšení stupňů volnosti. Dále je analyzováno chování jednoho vibračního generátoru se sinusovým buzením a jednoho s reálným buzením s využítím počítačového modelu v Matlab & Simulink. Především je kladen důraz na výstupní elektrický výkon a energii v závislosti na různých geometrických parametrech a elektromagnetickém tlumení., The first part of this bachelor’s thesis is an overview of vibration energy harversters with multiple degrees of freedom. Several options of broadening the usefull frequency bandwidth thanks to multiple degrees of freedom are described in the overview. The following part is a model in Matlab & Simulink analyzing behaviour of a vibration-powered generator with a harmonic excitation and another one with a real excitation. The main focus is on the output electrical power and energy in relation to geometrical parameters and electromagnetic damping.

355. Analýza chování modelu vibračního generátoru s více stupni volnosti

Author

Hadaš, Zdeněk, Rubeš, Ondřej, Hadaš, Zdeněk, and Rubeš, Ondřej

Abstract

Na začátku této bakalářské práce je rešerše vibračních generátorů s více stupni volnosti. V rešerši jsou uvedeny různé možnosti rozšíření užitečného frekvenčního pásma pomocí zvýšení stupňů volnosti. Dále je analyzováno chování jednoho vibračního generátoru se sinusovým buzením a jednoho s reálným buzením s využítím počítačového modelu v Matlab & Simulink. Především je kladen důraz na výstupní elektrický výkon a energii v závislosti na různých geometrických parametrech a elektromagnetickém tlumení., The first part of this bachelor’s thesis is an overview of vibration energy harversters with multiple degrees of freedom. Several options of broadening the usefull frequency bandwidth thanks to multiple degrees of freedom are described in the overview. The following part is a model in Matlab & Simulink analyzing behaviour of a vibration-powered generator with a harmonic excitation and another one with a real excitation. The main focus is on the output electrical power and energy in relation to geometrical parameters and electromagnetic damping.

356. Analýza chování modelu vibračního generátoru s více stupni volnosti

Author

Hadaš, Zdeněk, Rubeš, Ondřej, Hadaš, Zdeněk, and Rubeš, Ondřej

Abstract

Na začátku této bakalářské práce je rešerše vibračních generátorů s více stupni volnosti. V rešerši jsou uvedeny různé možnosti rozšíření užitečného frekvenčního pásma pomocí zvýšení stupňů volnosti. Dále je analyzováno chování jednoho vibračního generátoru se sinusovým buzením a jednoho s reálným buzením s využítím počítačového modelu v Matlab & Simulink. Především je kladen důraz na výstupní elektrický výkon a energii v závislosti na různých geometrických parametrech a elektromagnetickém tlumení., The first part of this bachelor’s thesis is an overview of vibration energy harversters with multiple degrees of freedom. Several options of broadening the usefull frequency bandwidth thanks to multiple degrees of freedom are described in the overview. The following part is a model in Matlab & Simulink analyzing behaviour of a vibration-powered generator with a harmonic excitation and another one with a real excitation. The main focus is on the output electrical power and energy in relation to geometrical parameters and electromagnetic damping.

357. Analýza chování modelu vibračního generátoru s více stupni volnosti

Author

Hadaš, Zdeněk, Rubeš, Ondřej, Hadaš, Zdeněk, and Rubeš, Ondřej

Abstract

Na začátku této bakalářské práce je rešerše vibračních generátorů s více stupni volnosti. V rešerši jsou uvedeny různé možnosti rozšíření užitečného frekvenčního pásma pomocí zvýšení stupňů volnosti. Dále je analyzováno chování jednoho vibračního generátoru se sinusovým buzením a jednoho s reálným buzením s využítím počítačového modelu v Matlab & Simulink. Především je kladen důraz na výstupní elektrický výkon a energii v závislosti na různých geometrických parametrech a elektromagnetickém tlumení., The first part of this bachelor’s thesis is an overview of vibration energy harversters with multiple degrees of freedom. Several options of broadening the usefull frequency bandwidth thanks to multiple degrees of freedom are described in the overview. The following part is a model in Matlab & Simulink analyzing behaviour of a vibration-powered generator with a harmonic excitation and another one with a real excitation. The main focus is on the output electrical power and energy in relation to geometrical parameters and electromagnetic damping.

358. Analýza chování modelu vibračního generátoru s více stupni volnosti

Author

Hadaš, Zdeněk, Rubeš, Ondřej, Witassek, Tomáš, Hadaš, Zdeněk, Rubeš, Ondřej, and Witassek, Tomáš

Abstract

Na začátku této bakalářské práce je rešerše vibračních generátorů s více stupni volnosti. V rešerši jsou uvedeny různé možnosti rozšíření užitečného frekvenčního pásma pomocí zvýšení stupňů volnosti. Dále je analyzováno chování jednoho vibračního generátoru se sinusovým buzením a jednoho s reálným buzením s využítím počítačového modelu v Matlab & Simulink. Především je kladen důraz na výstupní elektrický výkon a energii v závislosti na různých geometrických parametrech a elektromagnetickém tlumení., The first part of this bachelor’s thesis is an overview of vibration energy harversters with multiple degrees of freedom. Several options of broadening the usefull frequency bandwidth thanks to multiple degrees of freedom are described in the overview. The following part is a model in Matlab & Simulink analyzing behaviour of a vibration-powered generator with a harmonic excitation and another one with a real excitation. The main focus is on the output electrical power and energy in relation to geometrical parameters and electromagnetic damping.

359. Biomechanics of the Human Gait

Author

E. Y. S. Chao

Subjects
Multiple degrees of freedom, medicine.medical_specialty, Psychomotor control, Gait (human), Physical medicine and rehabilitation, Computer science, Gait analysis, Biomechanics, medicine, Objective analysis, Human locomotion, Task (project management)
Abstract

Humans perform physical activities in a variety of ways, depending upon individual anatomical structure, physiological functions, psychomotor control patterns, and associated pathological or chronological changes. In addition, many of our physical activities are task-oriented, varying drastically due to personal habit, training, and motivation. Assuming that our limb segments are compound pendulums with multiple degrees of freedom, the infinite possibilities for achieving a given task make objective analysis and modeling of human physical activities an intractable problem in modern biomechanics. However, human locomotion represents a unique subset of such activities that can be studied with an acceptable degree of accuracy if the limb segments to be included are limited to only the lower extremities. This specific branch of biomechanics is defined as gait analysis—a quantitative description of human locomotion.

Published
1986

360. Finger-Arm Coordination Control Method for Multiple Degrees of Freedom Robot

Author

I. Kato and S. Sugano

Subjects
Multiple degrees of freedom, business.industry, Computer science, Work (physics), technology, industry, and agriculture, food and beverages, body regions, Finger movement, surgical procedures, operative, Robot, Computer vision, Artificial intelligence, business, human activities, Control methods, Sequence (medicine)
Abstract

This paper proposes a method of controlling the coordination of the fingers and the arm when performing robot work which can be expressed as a sequence of continuous changes in positioning points of robot linger tips.

Published
1987

361. Dynamic analysis of a cantilever beam with a multiple degrees of freedom system

Author

H.B. Tang and Bingang Xu

Subjects
Multiple degrees of freedom, Engineering, Cantilever, Acoustics and Ultrasonics, Field (physics), business.industry, Mechanical Engineering, Public Health, Environmental and Occupational Health, Aerospace Engineering, Building and Construction, Structural engineering, Industrial and Manufacturing Engineering, Vibration, Dynamic Vibration Absorber, Early results, Automotive Engineering, business, Beam (structure), Matrix method
Abstract

A beam attached to a multiple degrees of freedom system is a common and complex structure in a broad field of engineering and science. The paper presents a novel and efficient computer model for dynamic analysis of a cantilever beam structure attached to a multiple degrees of freedom system by means of the recurrence matrix method. In this model, the forced responses and natural characteristics of the coupled beam are achieved and numerical simulations of the established model agree well with the early results. Finally, the vibration reductions of a beam by a dynamic vibration absorber are numerically studied.

362. Highly intuitive 3-DOF simultaneous and proportional myocontrol of wrist and hand

Author

Ivan Vujaklija, Dario Farina, Claudio Castellini, and Markus Nowak

Subjects
Multiple degrees of freedom, myocontrol, medicine.anatomical_structure, assistive robotics, EMG, machine learning, Control theory, medicine, Wrist, prosthetics, Closing (morphology), Rotation (mathematics), Mathematics
Abstract

While simultaneous and proportional activation of multiple degrees of freedom (DOFs) is supported by novel prosthetic hands, there are still no commercial controllers to appropriately enable it. Here, we test a ridge regression based myocontrol method in two real-time scenarios: 13 subjects with an extended high-density EMG electrode set (192 channels) and 4 subjects with a reduced set of electrodes (16 channels). In each scenario, the algorithm was trained on 3 repetitions of single DOF motions (rest, wrist flexion/extension and rotation, and hand closing) and then subjects were asked to reach 24 on-screen goals consisting of one-DOF, two-DOF, and three-DOF targets. The results showed that participants were able to reach all types of targets and that their one-DOF success rate remained high despite the simultaneous control of multiple DoFs (\(95.9\pm 5.7\%\)). Moreover, the performance did not significantly change when reducing the number of electrodes (\(97.6\pm 4.5\%\) for 16 channels).

363. Computerized CHI Squared: Multiple Degrees of Freedom

Author

Bertram R. Forer

Subjects
Multiple degrees of freedom, Statistics, Chi-square test, Experimental and Cognitive Psychology, Sensory Systems, Mathematics
Abstract

A reusable template for calculation of chi squared with more than one degree of freedom can utilize Visicalc but can be easily adapted to Multiplan or other spread-sheet softwares. Alternative methods for simplifying its use in calculating chi squared with varying degrees of freedom is presented. Placing the formulas in the computer on a disk is rote and calculations are automatic. Minimum computer sophistication is needed.

Published
1984

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