Stick-Slip Chaos in a Non-Ideal Self-Excited System

2003 ◽  
Author(s):  
B. R. Pontes ◽  
J. M. Balthazar ◽  
V. A. Oliveira
Keyword(s):  
Power Supply ◽  
Dry Friction ◽  
Dynamic Structure ◽  
Oil Well ◽  
Chaotic Oscillations ◽  
Stick Slip ◽  
Excited System ◽  
Limited Power ◽  
Limited Power Supply ◽  
And Control

In engineering practical systems the excitation source is generally dependent on the system dynamic structure. In this paper we analyze a self-excited oscillating system due to dry friction which interacts with an energy source of limited power supply (non ideal problem). The mechanical system consists of an oscillating system sliding on a moving belt driven by a limited power supply. In the oscillating system considered here, dry friction acts as an excitation mechanism for stick-slip oscillations. The stick-slip chaotic oscillations are investigated because the knowledge of their dynamic characteristics is an important step in system design and control. Many engineering systems present stick-slip chaotic oscillations such as machine tools, oil well drillstrings, car brakes and others.

On nonlinear dynamics behavior and control of a new model of a magnetically levitated vibrating system, excited by an unbalanced DC motor of limited power supply

2014 ◽  
Vol 37 (4) ◽  
pp. 1139-1150 ◽  
Author(s):  
Hassan Costa Arbex ◽  
José Manoel Balthazar ◽  
Bento Rodrigues de Pontes Junior ◽  
Reyolando Manoel Lopes Rebello da Fonseca Brasil ◽  
Jorge Luis Palacios Felix ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Power Supply ◽  
Dc Motor ◽  
New Model ◽  
Vibrating System ◽  
Limited Power ◽  
Limited Power Supply ◽  
Magnetically Levitated ◽  
And Control

Vibration of Asymmetric Rotor through Critical Speed with Limited Power Supply

1972 ◽  
Vol 14 (3) ◽  
pp. 184-194 ◽  
Author(s):  
T. Iwatsubo ◽  
H. Kanki ◽  
R. Kawai
Keyword(s):  
Power Supply ◽  
Critical Speed ◽  
Damping Coefficients ◽  
Asymmetric Rotor ◽  
Acceleration And Deceleration ◽  
Stationary Vibration ◽  
Limited Power ◽  
Limited Power Supply ◽  
The Many ◽  
Driving Torque

The non-stationary vibration of an asymmetric rotor with limited power supply is studied using the asymptotic method. The many factors which affect the transient vibrating behaviour of the asymmetric rotor in passing through critical speed are studied in relation to the amplitude of motion, phase angle, energy, etc. by numerical calculation; that is, stiffness ratio of the asymmetric rotor, damping coefficients, driving torque (during both acceleration and deceleration) and so on. The experimental study using a simple model is added.

scholarly journals Inter-Stage Output Voltage Amplitude Improvement Circuit Integrated with Class-B Transmit Voltage Amplifier for Mobile Ultrasound Machines

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6244 ◽  
Author(s):  
Kiheum You ◽  
Hojong Choi
Keyword(s):  
Power Supply ◽  
Piezoelectric Transducer ◽  
Output Voltage ◽  
Piezoelectric Transducers ◽  
Voltage Amplitude ◽  
Voltage Amplifier ◽  
Class B ◽  
Voltage Signal ◽  
Limited Power ◽  
Limited Power Supply

Piezoelectric transducers are triggered by the output voltage signal of a transmit voltage amplifier (TVA). In mobile ultrasound instruments, the sensitivity of piezoelectric transducers is a critical parameter under limited power supply from portable batteries. Therefore, the enhancement of the output voltage amplitude of the amplifier under limited power supply could increase the sensitivity of the piezoelectric transducer. Several-stage TVAs are used to increase the voltage amplitude. However, inter-stage design issues between each TVA block may reduce the voltage amplitude and bandwidth because the electronic components of the amplifier are nonlinearly operated at the desired frequency ranges. To compensate for this effect, we propose a novel inter-stage output voltage amplitude improvement (OVAI) circuit integrated with a class-B TVA circuit. We performed fundamental A-mode pulse-echo tests using a 15-MHz immersion-type piezoelectric transducer to verify the design. The echo amplitude and bandwidth when using an inter-stage OVAI circuit integrated with a class-B TVA circuit (696 mVPP and 29.91%, respectively) were higher than those obtained when using only the class-B TVA circuit (576 mVPP and 24.21%, respectively). Therefore, the proposed OVAI circuit could be beneficial for increasing the output amplitude of the class-B TVA circuit for mobile ultrasound machines.

Draft: Stick-Slip Motions of a Rotor-Stator System

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Nicholas Vlajic ◽  
Chien-Min Liao ◽  
Hamad Karki ◽  
Balakumar Balachandran
Keyword(s):  
Dry Friction ◽  
Torsional Oscillation ◽  
Flexible Structures ◽  
Oil Well ◽  
Torsional Vibrations ◽  
Dimensional Model ◽  
Torsional Mode ◽  
Stick Slip ◽  
Finite Dimensional ◽  
Motion State

In the current study, the authors examine the torsional vibrations of a rotor enclosed within a stator subjected to dry friction. Through the experiments, it is demonstrated that forward whirling of the rotor occurs while in contact with the stator, backward whirling occurs with contact, as well as impacting motions, which are characterized by nonsynchronous whirling with rotor-stator collisions. While undergoing these motions, the torsional oscillations are excited by stick-slip interactions. Experimental data are presented to show the presence of a stable torsional mode dominated motion while subjected to stick-slip forces during dry-friction whirling. In this motion state, the torsional oscillation response occurs at a combination of frequencies including drive and whirl frequencies. A finite dimensional model is constructed and simulations carried out by using this model are able to capture the system dynamics, including the torsional responses observed during dry-friction whirling. Numerical results obtained by using this model are consistent with experimental observations. The findings of this study are relevant to whirling motions experienced by rotating, long flexible structures, such as drill strings used in oil-well explorations.

Dynamics of a Piecewise-Linear Oscillator With Limited Power Supply

2009 ◽  
Author(s):  
Silvio L. T. de Souza ◽  
Ibereˆ L. Caldas ◽  
Jose´ M. Balthazar ◽  
Reyolando M. L. R. F. Brasil
Keyword(s):  
Power Supply ◽  
Piecewise Linear ◽  
Basins Of Attraction ◽  
Point Of View ◽  
Restoring Force ◽  
Rich Variety ◽  
Coexistence Of Attractors ◽  
Limited Power ◽  
Limited Power Supply ◽  
Basins Of Attractions

We discuss dynamics of a vibro-impact system consisting of a cart with an piecewise-linear restoring force, which vibrates under driving by a source with limited power supply. From the point of view of dynamical systems, vibro-impact systems exhibit a rich variety of phenomena, particularly chaotic motion. In our analyzes, we use bifurcation diagrams, basins of attractions, identifying several non-linear phenomena, such as chaotic regimes, crises, intermittent mechanisms, and coexistence of attractors with complex basins of attraction.

scholarly journals Mining Wireless Sensor Network Data: an adaptive approach based on artificial neuralnetworks algorithm

2011 ◽  
pp. 129-135
Author(s):  
Lambodar Jena ◽  
Ramakrushna Swain ◽  
N.K. kamila
Keyword(s):  
Data Mining ◽  
Wireless Sensor Network ◽  
Sensor Networks ◽  
Dimensionality Reduction ◽  
Sensor Network ◽  
Power Supply ◽  
Sensor Data ◽  
Wireless Sensor ◽  
Limited Power ◽  
Limited Power Supply

This paper proposes a layered modular architecture to adaptively perform data mining tasks in large sensor networks. The architecture consists in a lower layer which performs data aggregation in a modular fashion and in an upper layer which employs an adaptive local learning technique to extract a prediction model from the aggregated information. The rationale of the approach is that a modular aggregation of sensor data can serve jointly two purposes: first, the organization of sensors in clusters, then reducing the communication effort, second, the dimensionality reduction of the data mining task, then improving the accuracy of the sensing task . Here we show that some of the algorithms developed within the artificial neuralnetworks tradition can be easily adopted to wireless sensor-network platforms and will meet several aspects of the constraints for data mining in sensor networks like: limited communication bandwidth, limited computing resources, limited power supply, and the need for fault-tolerance. The analysis of the dimensionality reduction obtained from the outputs of the neural-networks clustering algorithms shows that the communication costs of the proposed approach are significantly smaller, which is an important consideration in sensor-networks due to limited power supply. In this paper we will present two possible implementations of the ART and FuzzyART neuralnetworks algorithms, which are unsupervised learning methods for categorization of the sensory inputs. They are tested on a data obtained from a set of several nodes, equipped with several sensors each.

Chaos in vibrating systems with a limited power‐supply

1993 ◽  
Vol 3 (3) ◽  
pp. 387-395 ◽  
Author(s):  
Tatyana S. Krasnopolskaya ◽  
Alexander Yu. Shvets
Keyword(s):  
Power Supply ◽  
Limited Power ◽  
Limited Power Supply ◽  
Vibrating Systems
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