scholarly journals Self-Sustained Oscillation of a Photothermal-Responsive Pendulum under Steady Illumination

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Dali Ge ◽  
Peibao Xu ◽  
Kai Li
Keyword(s):  
Oscillation Mode ◽  
Self Control ◽  
Sustained Oscillation ◽  
Static Mode ◽  
System Parameters ◽  
Simple Pendulum ◽  
Oscillating Systems ◽  
Motion Modes ◽  
Potential Applications ◽  
Excited Oscillation

Self-sustained oscillation has the advantages of harvesting energy from the environment and self-control, and thus, the development of new self-oscillating systems can greatly expand its applications in active machines. In this paper, based on conventional photothermal shrinkable material or photothermal expansive material, a simple pendulum is proposed. The light-powered self-sustained oscillation of the simple pendulum is theoretically studied by establishing a dynamic model of the photothermal-responsive pendulum. The results show that there are two motion modes of the simple pendulum, which are the static mode and the oscillation mode. Based on the photothermal-responsive model, this paper elucidates the mechanism of the self-excited oscillation. The condition for triggering self-excited oscillation is further studied. In addition, the influence of the system parameters on the amplitude and frequency is also obtained. This study may have potential applications in energy harvesting, signal monitoring, and soft machines.

Chaotic Attractor in a Novel Time-Delayed System with a Saturation Function

2015 ◽  
pp. 230-258 ◽  
Author(s):  
Viet-Thanh Pham ◽  
Christos Volos ◽  
Sundarapandian Vaidyanathan
Keyword(s):  
Time Delay ◽  
Nonlinear Behavior ◽  
Chaotic Signal ◽  
Delay Systems ◽  
Maximum Lyapunov Exponent ◽  
System Parameters ◽  
Saturation Function ◽  
Potential Applications ◽  
Delayed System ◽  
Chaotic Signal Generator

From the viewpoint of engineering applications, time delay is useful for constructing a chaotic signal generator, which is the major part of diverse potential applications. Although different mathematical models of time-delay systems have been known, few models can exhibit chaotic behaviors. Motivated by attractive features and potential applications of time-delay models, a new chaotic system with a single scalar time delay and a nonlinearity described by a saturation function is proposed in this chapter. Nonlinear behavior of the system is discovered through bifurcation diagrams and the maximum Lyapunov exponent with the variance of system parameters. Interestingly, the system shows double-scroll chaotic attractors for some suitable chosen system parameters. In order to confirm the correction and feasibility of the theoretical model, the system is also implemented with analog electronic circuit. Finally, a practical application of such circuit is discussed at the end of this chapter.

scholarly journals A Self-Stabilized Inverted Pendulum Made of Optically Responsive Liquid Crystal Elastomers

2022 ◽  
Vol 8 ◽  
Author(s):  
Quanbao Cheng ◽  
Lin Zhou ◽  
Kai Li
Keyword(s):  
Liquid Crystal ◽  
Inverted Pendulum ◽  
The Self ◽  
Sustained Oscillation ◽  
Static State ◽  
Pendulum System ◽  
Liquid Crystal Elastomer ◽  
Inverted Pendulum System ◽  
Potential Applications ◽  
Liquid Crystal Elastomers

The inverted pendulum system has great potential for various engineering applications, and its stabilization is challenging because of its unstable characteristic. The well-known Kapitza’s pendulum adopts the parametrically excited oscillation to stabilize itself, which generally requires a complex controller. In this paper, self-sustained oscillation is utilized to stabilize an inverted pendulum, which is made of a V-shaped, optically responsive liquid crystal elastomer (LCE) bar under steady illumination. Based on the well-established dynamic LCE model, a theoretical model of the LCE inverted pendulum is formulated, and numerical calculations show that it always develops into the unstable static state or the self-stabilized oscillation state. The mechanism of the self-stabilized oscillation originates from the reversal of the gravity moment of the inverted pendulum accompanied with its own movement. The critical condition for triggering self-stabilized oscillation is fully investigated, and the effects of the system parameters on the stability of the inverted pendulum are explored. The self-stabilized inverted pendulum does not need an additional controller and offers new designs of self-stabilized inverted pendulum systems for potential applications in robotics, military industry, aerospace, and other fields.

scholarly journals Numerical simulation of the flow of viscous incompressible fluid through cylindrical cavities

2019 ◽  
pp. 218-221
Author(s):  
Ya. P. Trotsenko
Keyword(s):  
Incompressible Fluid ◽  
Shear Layer ◽  
Stokes Equations ◽  
Viscous Incompressible Fluid ◽  
Oscillation Mode ◽  
Navier Stokes ◽  
Sustained Oscillation ◽  
Tvd Scheme ◽  
Algebraic Equations ◽  
Linear Algebraic Equations

The flow of viscous incompressible fluid in a cylindrical duct with two serial diaphragms is studied by the numerical solution of the unsteady Navier–Stokes equations. The discretization procedure is based on the finite volume method using the TVD scheme for the discretization of the convective terms and second order accurate in both space and time difference schemes. The resulting system of non-linear algebraic equations is solved by the PISO algorithm. It is shown that the fluid flow in the region between the diaphragms is nonstationary and is characterized by the presence of an unstable shear layer under certain parameters. A series of ring vortices is formed in the shear layer that causes quasi-periodic self-sustained oscillations of the velocity and pressure fields in the orifice of the second diaphragm. There can be four self-sustained oscillation modes depending on the length of the cavity formed by the diaphragms. With the increase in the distance between the diaphragms, the frequency of oscillations decreases within the same self-oscillation mode and rises sharply with the switch to the next mode.

scholarly journals Light-powered Self-excited Coupled Oscillators in Huygens ’ Synchrony

2021 ◽  
Author(s):  
Quanbao Cheng ◽  
Kai Li
Keyword(s):  
Coupled Oscillators ◽  
Phase Synchronization ◽  
Initial Conditions ◽  
Strong Interactions ◽  
Liquid Crystal Elastomer ◽  
Synchronization Mode ◽  
Motion Modes ◽  
Excited Oscillation ◽  
Time Histories ◽  
Excited Oscillator

Abstract Self-excited motions have the advantages of actively collecting energy from the environment, autonomy, making equipment portable and so on, and a great number of self-excited motion modes have recently been developed which greatly expand the application in active machines. However, there are few studies on the synchronization and group behaviors of self-excited coupled oscillators, which are common in nature. Based on light-powered self-excited oscillator composed of liquid crystal elastomer (LCE) bars, the synchronization of two self-excited coupled oscillators is theoretically studied. Numerical calculations show that self-excited oscillations of the system have two synchronization modes: in-phase mode and anti-phase mode. The time histories of various quantities are calculated to elucidate the mechanism of self-excited oscillation and synchronization. Furthermore, the effects of initial conditions and interaction on the two synchronization modes of the self-excited oscillation are investigated extensively. For strong interactions, the system always develops into in-phase synchronization mode, while for weak interaction, the system will evolve into anti-phase synchronization mode. Meanwhile, the initial condition generally does not affect the synchronization mode and its amplitude. This work will deepen people's understanding of synchronization behaviors of self-excited coupled oscillators, and provide promising applications in energy harvesting, signal monitoring, soft robotics and medical equipment.

Adjustable-Smooth Polynomial Command-Shaping Control With Linear Hoisting

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Khalid A. Alghanim ◽  
Majed A. Majeed ◽  
Khaled A. Alhazza
Keyword(s):  
Input Signal ◽  
Polynomial Function ◽  
Equation Of Motion ◽  
Modal Parameters ◽  
Input Shaping ◽  
Overhead Crane ◽  
Command Shaping ◽  
System Parameters ◽  
Cable Length ◽  
Simple Pendulum

Great amount of work has been dedicated to eliminate residual vibrations in rest-to-rest motion. Considerable amount of these methods is based on convolving a general input signal with a sequence of timed impulses. These impulses usually have large jumps in their profiles and are chosen depending on the system modal parameters. Furthermore, classical input shaping methods are usually used for constant cable length and are sensitive to any change in the system parameters. To overcome these limitations, polynomial command shapers with adjustable maneuvering time are proposed. The equation of motion of a simple pendulum with the effect of hoisting is derived, linearized, and solved in order to eliminate residual vibrations in rest-to-rest maneuvers. Several cases including smooth, semi-smooth and unsmooth continuous shapers are simulated numerically and validated experimentally on an experimental overhead crane. Numerical and experimental results show that the proposed polynomial command shaper eliminates residual vibrations effectively. The effect of linear hoisting is also included and discussed. To enhance the shaper performance, extra parameters are added to the polynomial function to reduce shaper sensitivity. Results show that the effect of adding these parameters greatly enhances the shaper performance.

scholarly journals Characterisation and Manipulation of Polarisation Response in Plasmonic and Magneto-Plasmonic Nanostructures and Metamaterials

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1365
Author(s):  
Pritam Khan ◽  
Grace Brennan ◽  
James Lillis ◽  
Syed A. M. Tofail ◽  
Ning Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Recent Progress ◽  
Oscillation Mode ◽  
Metal Nanostructures ◽  
Plasmonic Nanostructures ◽  
Oscillation Modes ◽  
Potential Applications

Optical properties of metal nanostructures, governed by the so-called localised surface plasmon resonance (LSPR) effects, have invoked intensive investigations in recent times owing to their fundamental nature and potential applications. LSPR scattering from metal nanostructures is expected to show the symmetry of the oscillation mode and the particle shape. Therefore, information on the polarisation properties of the LSPR scattering is crucial for identifying different oscillation modes within one particle and to distinguish differently shaped particles within one sample. On the contrary, the polarisation state of light itself can be arbitrarily manipulated by the inverse designed sample, known as metamaterials. Apart from polarisation state, external stimulus, e.g., magnetic field also controls the LSPR scattering from plasmonic nanostructures, giving rise to a new field of magneto-plasmonics. In this review, we pay special attention to polarisation and its effect in three contrasting aspects. First, tailoring between LSPR scattering and symmetry of plasmonic nanostructures, secondly, manipulating polarisation state through metamaterials and lastly, polarisation modulation in magneto-plasmonics. Finally, we will review recent progress in applications of plasmonic and magneto-plasmonic nanostructures and metamaterials in various fields.

Production of Porous Poly(p-dioxanone) Fibers during the Neck Propagation in Self-Excited Oscillation Mode

2020 ◽  
Vol 495 (1) ◽  
pp. 176-179
Author(s):  
M. A. Khavpachev ◽  
E. S. Trofimchuk ◽  
A. V. Efimov ◽  
N. I. Nikonorova ◽  
V. A. Demina ◽  
...  
Keyword(s):  
Oscillation Mode ◽  
Excited Oscillation ◽  
Neck Propagation ◽  
Porous Poly

Kinetic Building Envelopes for Energy Efficiency: Modeling and Products

2011 ◽  
Vol 71-78 ◽  
pp. 621-625 ◽  
Author(s):  
Zhan Tang Miao ◽  
Jing Li ◽  
Jia Liang Wang
Keyword(s):  
Energy Efficiency ◽  
Experimental Design ◽  
Sustainable Design ◽  
Building Envelope ◽  
Building Envelopes ◽  
Motion Patterns ◽  
Interdisciplinary Design ◽  
Motion Modes ◽  
Potential Applications ◽  
Insight Into

Adaptive Building Envelope was discussed in recent years and became a possible solution for energy efficiency. We conducted a study of kinetic building envelopes for energy efficiency in the context of an interdisciplinary design & modeling course in 2010 Fall. The goals of these experimental design & modeling projects are to explore the possibilities of motion modes, the integration with whole envelopes and the potentials of applications, and to provide insight into sustainable design. This paper provides an experimental account of kinetic logics and products, and summarizes kinetic motion patterns and potential applications.

Sign in / Sign up

Export Citation Format

Share Document