Payload oscillation control of tower crane using smooth command input

2021 ◽  
pp. 107754632110546
Author(s):  
Abdulaziz Al-Fadhli ◽  
Emad Khorshid
Keyword(s):  
Sine Wave ◽  
Wave Functions ◽  
Particle Swarm Algorithm ◽  
Nonlinear Mathematical Model ◽  
Tower Crane ◽  
Oscillation Control ◽  
Input Shaper ◽  
Wide Range ◽  
Command Input ◽  
Tangential Acceleration

This paper presents a smooth command (SC) input shaper for suppressing payload oscillations in rest-to-rest simultaneous radial and tangential motions of a tower crane. The radial and tangential acceleration profiles of the compound motions are represented by multi-sine wave functions with independent and variable maneuvering time. The proposed SC is designed using a nonlinear mathematical model of the tower crane while the parameters of the acceleration profiles and maneuvering times were optimized using a particle swarm algorithm (PSO). The simulated results were verified experimentally on a laboratory scale tower crane. The results confirm that the proposed SC input effectively canceled residual vibrations of the payload compound motions with a time length comparable to zero vibrations (ZV) shaper. Moreover, sensitivity analysis to variations in cable length reveals that the proposed command input is robust over a wide range of cable lengths.

scholarly journals Payload swing control of a tower crane using a neural network–based input shaper

2020 ◽  
Vol 53 (7-8) ◽  
pp. 1171-1182 ◽  
Author(s):  
SM Fasih ◽  
Z Mohamed ◽  
AR Husain ◽  
L Ramli ◽  
AM Abdullahi ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Natural Frequency ◽  
Damping Ratio ◽  
Parameter Uncertainties ◽  
Cable Length ◽  
Tower Crane ◽  
Input Shaper ◽  
Average Operating ◽  
Artificial Neural

This paper proposes an input shaping technique for efficient payload swing control of a tower crane with cable length variations. Artificial neural network is utilized to design a zero vibration derivative shaper that can be updated according to different cable lengths as the natural frequency and damping ratio of the system changes. Unlike the conventional input shapers that are designed based on a fixed frequency, the proposed technique can predict and update the optimal shaper parameters according to the new cable length and natural frequency. Performance of the proposed technique is evaluated by conducting experiments on a laboratory tower crane with cable length variations and under simultaneous tangential and radial crane motions. The shaper is shown to be robust and provides low payload oscillation with up to 40% variations in the natural frequency. With a 40% decrease in the natural frequency, the superiority of the artificial neural network–zero vibration derivative shaper is confirmed by achieving at least a 50% reduction in the overall and residual payload oscillations when compared to the robust zero vibration derivative and extra insensitive shapers designed based on the average operating frequency. It is envisaged that the proposed shaper can be further utilized for control of tower cranes with more parameter uncertainties.

A Study on the Characteristics of a Vibrator Using Flat PCB-Coil

2013 ◽  
Vol 392 ◽  
pp. 738-742 ◽  
Author(s):  
Hyung Sik Kim ◽  
Sang Pyo Hong ◽  
Mi Hyun Choi ◽  
Hyun Joo Kim ◽  
In Hwa Lee ◽  
...  
Keyword(s):  
Vibration Amplitude ◽  
Printed Circuit Board ◽  
Cooling System ◽  
Sine Wave ◽  
Circuit Board ◽  
Frequency Change ◽  
Tactile Stimulator ◽  
Custom Made ◽  
Wide Range ◽  
Fiberglass Cloth

In this study, we developed and evaluateda vibrator using a flat PCB-coil. The flat PCB-coil vibrator was fabricated on a printed circuit board using and etching process. The spiral pattern was etched on a fiberglass cloth with an epoxy resin. To evaluatethe flat PCB-coil vibrator, we generated a sine wave, saw-tooth, and square wave through a custom made wave generator and amplified the waveforms using a power amplifier. A three-axis accelerometer was used to evaluate the performance of the developed vibrator. Even though the developed vibrator is simple, it has a wide range of vibration frequency (50~500 Hz) and vibration amplitude (0~5 V). The vibration amplitude does not change due to frequency change. It is expected that the developed vibrator can be used in a wide variety of applications such as in a tactile stimulator, in elastography, energy harvesting, and in a cooling system.

The Impact of Micro-Surface Shaping on the Piston/Cylinder Interface of Swash Plate Type Machines

2015 ◽  
Author(s):  
Ashley M. Wondergem ◽  
Monika Ivantysynova
Keyword(s):  
Surface Profile ◽  
Sine Wave ◽  
Operating Conditions ◽  
Surface Shape ◽  
Hydrodynamic Bearing ◽  
Piston Cylinder ◽  
Wide Range ◽  
Surface Shaping ◽  
Pumping Mode ◽  
The Impact

With the wide use of axial piston machines of the swashplate type in industry, it is essential to maximize the overall efficiency of the machines. Focusing on the piston-cylinder interface, as it performs as a hydrodynamic bearing simultaneously fulfilling a sealing function, the overall machine can be improved by reducing the power losses due to viscous friction and leakage flow of this interface. This paper presents a research study in regards to altering the geometry of the piston through micro-surface shaping influencing the generation of the fluid film between the piston and the cylinder. This investigation utilizes a novel fully coupled fluid structure interaction model considering both thermal and elastic deformations of the solid bodies to predict the phenomena occurring within the fluid gap. Encompassed in this simulation study is a diversity of piston micro-surface shapes and a wide range of machine operating conditions. The designs presented include an axial sine wave, a flat, cylindrical design with tapered ends, a barreled shape, a combination of the axial sine wave and barrel, along with a circumferential sine wave. High pressure operating conditions in pumping mode as well as common operating conditions in both pumping and motoring mode are considered for the various designs. The results demonstrate up to a 30% reduction in energy dissipation from a standard piston-cylinder interface at higher pressure operating conditions (over 15% reduction considering all three interfaces of the machine) with the addition of a barrel surface shape while a 25% reduction (over 5% overall) is achievable at lower operating pressures in pumping mode with a waved barrel surface profile. As for motoring mode a 30% reduction (around 10% overall) is possible with the introduction of a waved barrel surface profile on the piston. It will also be shown, that not only are these reductions possible though microsurface shaping of the piston, but the reliability of the machine is also improved by reducing run-in wear all while maintaining a cost-effective, manufacturable design.

Numerical Analysis on the Effect of Wavy Partitions on Natural Convection in Porous Enclosure

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Jayesh Subhash Chordiya ◽  
Ram Vinoy Sharma
Keyword(s):  
Natural Convection ◽  
Convection Heat Transfer ◽  
Sine Wave ◽  
Flow In Porous Media ◽  
Governing Equations ◽  
Wave Shape ◽  
Square Wave ◽  
Wide Range ◽  
Replacement Scheme ◽  
Porous Enclosure

Abstract The influence of partitions on natural convection in a differentially heated porous enclosure has been investigated for three different partition shapes, namely, sine-wave, corrugated and square-wave shape. The objective is to identify the best partition shape with regard to achieve maximum reduction in the rate of convection heat transfer. Darcy flow model has been used to describe flow in porous media. Coordinate transformation has been used to formulate the governing equations for sine-wave partition owing to its wavy nature. To assess the effectiveness of various partition shapes, the results are compared with porous enclosure without partition and with straight partition. The governing equations are solved using the successive accelerated replacement scheme for a wide range of parameters like partition amplitude, position, Rayleigh number, enclosure aspect ratio (AR), and inclination angle. One of the findings reveals that for the same amplitude and position, the square-wave partition yields the maximum suppression in the value of Nusselt number.

APPROXIMATE MOLECULAR ORBITALS: IV. THE 3dδg AND 4fδu STATES OF H2+

1967 ◽  
Vol 45 (8) ◽  
pp. 2533-2542 ◽  
Author(s):  
M. Cohen ◽  
R. P. McEachran ◽  
Sheila D. McPhee
Keyword(s):  
Perturbation Theory ◽  
Variational Methods ◽  
Excellent Agreement ◽  
Hydrogen Molecule ◽  
Wave Functions ◽  
Simple Criterion ◽  
Wide Range ◽  
Approximate Wave ◽  
Exact Calculations ◽  
Schrödinger Perturbation

Properties of the lowest even and odd δ states of the hydrogen molecule–ion have been calculated using approximate wave functions. These were derived using a combination of Rayleigh–Schrödinger perturbation theory and variational methods, which have been applied previously to calculate the corresponding wave functions of the lowest σ and π states. Our total molecular energies are in excellent agreement with the recent exact calculations of Hunter and Pritchard (1967). A simple criterion is suggested for judging the accuracy of the approximate orbitals, which indicates that all the molecular properties calculated will be accurate over a wide range of internuclear separations.

Atomic Resolution Phase Contrast Imaging and In-Line Holography Using Variable Voltage and Dose Rate

2012 ◽  
Vol 18 (5) ◽  
pp. 982-994 ◽  
Author(s):  
Bastian Barton ◽  
Bin Jiang ◽  
ChengYu Song ◽  
Petra Specht ◽  
Hector Calderon ◽  
...  
Keyword(s):  
Dose Rate ◽  
Phase Contrast ◽  
High Dose Rate ◽  
Wave Functions ◽  
Atomic Resolution ◽  
Phase Contrast Imaging ◽  
High Dose ◽  
Contrast Imaging ◽  
Variable Voltage ◽  
Wide Range

AbstractThe TEAM 0.5 electron microscope is employed to demonstrate atomic resolution phase contrast imaging and focal series reconstruction with acceleration voltages between 20 and 300 kV and a variable dose rate. A monochromator with an energy spread of ≤0.1 eV is used for dose variation by a factor of 1,000 and to provide a beam-limiting aperture. The sub-Ångstrøm performance of the instrument remains uncompromised. Using samples obtained from silicon wafers by chemical etching, the [200] atom dumbbell distance of 1.36 Å can be resolved in single images and reconstructed exit wave functions at 300, 80, and 50 kV. At 20 kV, atomic resolution <2 Å is readily available but limited by residual lens aberrations at large scattering angles. Exit wave functions reconstructed from images recorded under low dose rate conditions show sharper atom peaks as compared to high dose rate. The observed dose rate dependence of the signal is explained by a reduction of beam-induced atom displacements. If a combined sample and instrument instability is considered, the experimental image contrast can be matched quantitatively to simulations. The described development allows for atomic resolution transmission electron microscopy of interfaces between soft and hard materials over a wide range of voltages and electron doses.

Nuclear structure dependence in analyzing powers?

1980 ◽  
Vol 58 (12) ◽  
pp. 1686-1690 ◽  
Author(s):  
W. R. Falk
Keyword(s):  
Nuclear Structure ◽  
Cross Sections ◽  
Form Factors ◽  
Wave Functions ◽  
Angular Distributions ◽  
Structure Dependence ◽  
Analyzing Powers ◽  
Wide Range ◽  
Configuration Mixing ◽  
The Cross

Calculations of the angular distributions of the cross-sections and analyzing powers in the [Formula: see text] Al reaction have been made using microscopic form factors. A wide range of shapes of the microscopic form factors, simulating different degrees of configuration mixing in the nuclear wave functions, fail to provide angular distributions of the analyzing powers that agree with experiment for the 2.73 and 4.41 MeV, 5/2+ states.

scholarly journals Design and Simulation of MPPT Control for Solar Powered AC Autonomous LED Lighting Applications in MATLAB/Simulink Environment

2020 ◽  
Vol 9 (4) ◽  
pp. 177-183
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Sine Wave ◽  
Boost Converter ◽  
Main Concept ◽  
Light Industry ◽  
Matlab Simulink ◽  
Led Lighting ◽  
Wide Range ◽  
Office Lighting

As an AC LED light applications have become a commonplace item of light industry, it has a wide range of usage in garden lighting, cove lighting, office lighting and retail applications. The paper brings out the utilization of Boost converter along with Maximum Power Point Tracker (MPPT) technique for the control of Photovoltaic power. This proposed system which includes Boost converter, a single phase full bridge inverter with Sinusoidal Pulse Width Modulation (SPWM) technique. The main concept of this converter includes designing of boost converter that provides an output voltage of 350V DC and single phase SPWM provides 350V, pure sine wave output (230V RMS) applicable to AC autonomous LED Lighting system. In order to bring out a transformer free inverter, the designed boost converter is simulated in the MATLAB Simulink software and the results are shown with low THD as per IEEE standard, with acceptable power factor and higher efficiency.

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