A smooth polynomial shaped command for sloshing suppression of a suspended liquid container

2020 ◽  
pp. 014233122094930
Author(s):  
Abdullah Alshaya ◽  
Dima Almujarrab
Keyword(s):  
Vibrational Modes ◽  
Governing Equations ◽  
Equivalent Mechanical Model ◽  
Proposed Model ◽  
Sloshing Dynamics ◽  
Liquid Depth ◽  
Mass Spring ◽  
Pendulum Dynamics ◽  
Multi Mode ◽  
Sloshing Suppression

A smooth polynomial shaped command with an adjustable command time length is proposed for eliminating the residual vibrations of a multi-mode system. The ability of eliminating jerks and vibrational modes, regardless of their number, offers the most advantage of the proposed command. A numerical simulation is conducted to test the command’s effectiveness by eliminating the residual sloshing oscillations of a liquid-filled container conveyed by an overhead crane in a rest-to-rest manoeuvre. The governing equations of the liquid free-surface level are derived by modelling the sloshing dynamics by a series of mass–spring–damper harmonics. The proposed model accounts for the coupling between the pendulum dynamics and the sloshing equivalent mechanical model. The command’s robustness to the system parameters’ uncertainties, liquid depth and cable length, are investigated as well. The ability of adjusting the command length and retaining higher sloshing modes in command-designing are also outlined.

Command Shaping for Sloshing Suppression of a Suspended Liquid Container

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Abdullah Alshaya ◽  
Khalid Alghanim
Keyword(s):  
Liquid Sloshing ◽  
Command Shaping ◽  
Equivalent Mechanical Model ◽  
Proposed Model ◽  
Sloshing Dynamics ◽  
Time Optimal ◽  
Free Surface Wave ◽  
Liquid Depth ◽  
Mass Spring ◽  
Input Command

Abstract The residuals of liquid free-surface wave oscillations induced by a rest-to-rest crane maneuver of a suspended liquid container are eliminated using a command-shaped profile. The dynamics of liquid sloshing are modeled using an equivalent mechanical model based on a series of mass-spring-damper systems. The proposed model considers the excited frequencies of the container swing motion and liquid sloshing modes. The objective is to design a discrete-time shaped acceleration profile with a variable command length that controls the moving crane-jib, while suppressing the sloshing modes. Simulations are conducted to illustrate the command effectiveness in eliminating liquid sloshing with a wide variation range of system and command-designing parameters; liquid depth, cable length, command duration, and the employing of higher sloshing modes in representing the sloshing dynamics. The command sensitivity of the input command to changes of the system parameters are treated as well. A refined and smooth input command based on suppressing the residuals of multimodes is also introduced. Furthermore, the command effectiveness was supported by a comparison with the time-optimal flexible-body control and multimode zero vibration input shaper.

scholarly journals A numerical study: liquid sloshing dynamics in a tank due to uncoupled sway, heave and roll ship motions

2013 ◽  
Vol 10 (2) ◽  
pp. 119-138 ◽  
Author(s):  
Nasar Thuvanismail ◽  
Sannasiraj Sannasi ◽  
Sundar Vallam
Keyword(s):  
Numerical Study ◽  
Energy Spectra ◽  
Qualitative Assessment ◽  
Ship Motions ◽  
Theoretical Studies ◽  
Sloshing Dynamics ◽  
Tank System ◽  
Liquid Depth ◽  
Sloshing Phenomenon ◽  
Heave Motion

In order to explore the physics implicated with the sloshing phenomenon subjected to independent regular sway, heave and roll excitations of the liquid tank system, theoretical studies are carried out. Four liquid fill levels with static liquid depth, hs, to the length, l of aspect ratio (hs/l) 0.163, 0.325, 0.488 and 0.585, are considered. The energy spectra of sloshing oscillation, their qualitative assessment and the harmonics present in the sloshing oscillation are studied. Frequency –Response amplitude has also been presented. The study reveals that sway excites a particular mode of sloshing (primary harmonic) by fulfilling the resonance conditions and also excites secondary modes. However, the roll motion excites the first mode of sloshing irrespective of the excitation frequencies. The heave motion excites the particular mode which is assumed as an initial perturbation.DOI: http://dx.doi.org/10.3329/jname.v10i2.16215 

A Numerical Method to Enhance the Accuracy of Mass-Spring Systems for Modeling Soft Tissue Deformations

2009 ◽  
Vol 25 (3) ◽  
pp. 271-278 ◽  
Author(s):  
Hadi Mohammadi
Keyword(s):  
Regular Function ◽  
Technical Note ◽  
Smooth Solutions ◽  
Governing Equations ◽  
Residual Function ◽  
Spring System ◽  
Mass Spring ◽  
Tissue Deformations ◽  
Spring Constants ◽  
Element Method

This technical note presents a numerical corrective technique that allows control of nonlinearity in a mass-spring system (MSS) independent of its spring constants or system topology. The governing equations of MSS in the form of ordinary differential equations or a regular function accompanied by any boundary or initial condition as known constraints, are employed to modify the results. A least-squares algorithm coupled with the finite difference method is used to discretize the basic residual function implemented in this corrective technique. This numerical solution is applicable to both static and dynamic MSS. This technique is easy to implement and has accuracy similar to that of the equivalent finite element method (FEM) solution to the same system whereas solutions are obtained in a fraction of the CPU time. The proposed technique can also be used to smooth solutions from other methods such as FEM or boundary element method (BEM).

scholarly journals A New Nonlinear Active Disturbance Rejection Control for the Cable Car System to Restrain the Vibration

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinyan Hu ◽  
Lina Li
Keyword(s):  
Disturbance Rejection ◽  
System Model ◽  
Active Disturbance Rejection Control ◽  
Active Disturbance Rejection ◽  
The People ◽  
Disturbance Rejection Control ◽  
Proposed Model ◽  
Spring System ◽  
Linear Invariant ◽  
Mass Spring

The safety of the cable car system is very important for the lives of the people. But, it is easily affected by the environment such as the wind which causes the cable car system to have strong vibration disturbance, thus degrading the safety of the cable car system. In this paper, a new nonlinear active disturbance rejection control (ADRC) is proposed to restrain the vibration of the cable car. First, a new two-mass-spring system model is utilized to establish the cable car system model. The new translation vibration nonlinear model is derived by a linear-invariant two-mass-spring system. Then, a special nonlinear fal• is designed to restrain the vibration, and a new high-order nonlinear ADRC is presented for the cable car system. Finally, simulation results verify the feasibility and accuracy of the proposed model.

On the vibration analysis of power lines with moving dampers

2017 ◽  
Vol 24 (18) ◽  
pp. 4096-4109 ◽  
Author(s):  
MA Bukhari ◽  
O Barry ◽  
E Tanbour
Keyword(s):  
Transmission Lines ◽  
Equations Of Motion ◽  
Power Lines ◽  
Governing Equations ◽  
Wind Force ◽  
Vibration Displacement ◽  
Mass System ◽  
Overhead Transmission Lines ◽  
Parametric Studies ◽  
Mass Spring

This work investigates the performance of a moving damper for overhead transmission lines. The damper or absorber consists of mass-spring-damper-mass system. The absorber is connected to a single conductor subjected to pretension and wind force. The governing equations of motion are obtained using Hamilton’s principle, and numerical analysis is carried out using MATLAB®. The model is validated by comparing the present results to those in the literature. Parametric studies are conducted to investigate the performance of the proposed absorber. The results indicate that a moving absorber can be more effective than a fixed absorber. It is also demonstrated that the vibration displacement decreases with increasing forcing frequency and decreasing absorber speed.

Transient Response of Inductrack Systems for Maglev Transport: Part II—Solution and Dynamic Analysis

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen Yang
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Transient Response ◽  
Numerical Procedure ◽  
Steady State Response ◽  
Governing Equations ◽  
Transient Model ◽  
State Response ◽  
Proposed Model ◽  
Non Linear

Abstract In Part I of this two-part paper, a new benchmark transient model of Inductrack systems is developed. In this Part II, the proposed model, which is governed by a set of non-linear integro-differential governing equations, is used to predict the dynamic response of Inductrack systems. In the development, a state-space representation of the non-linear governing equations is established and a numerical procedure with a specific moving circuit window for transient solutions is designed. The dynamic analysis of Inductrack systems with the proposed model has two major tasks. First, the proposed model is validated through comparison with the noted steady-state results in the literature. Second, the transient response of an Inductrack system is simulated and analyzed in several typical dynamic scenarios. The steady-state response results predicted by the new model agree with those obtained in the previous studies. On the other hand, the transient response simulation results reveal that an ideal steady-state response can hardly exist in those investigated dynamic scenarios. It is believed that the newly developed transient model provides a useful tool for dynamic analysis of Inductrack systems and for in-depth understanding of the complicated electro-magneto-mechanical interactions in this type of dynamic systems.

Modeling of Human Lower Extremity Musculo-Skeletal Structure Using Bond Graph Approach

2007 ◽  
Author(s):  
Ali Selk Ghafari ◽  
Ali Meghdari ◽  
Gholam Reza Vossoughi
Keyword(s):  
Sagittal Plane ◽  
Equations Of Motion ◽  
Bond Graph ◽  
Skeletal Structure ◽  
Governing Equations ◽  
Straight Line ◽  
Proposed Model ◽  
In Series ◽  
Muscular Function ◽  
Mechanical Linkage

A vector bond graph approach for dynamic modeling of human musculo-skeletal system is addressed in this article. In the proposed model, human body is modeled as a ten-segment, nine degree of freedom, mechanical linkage, actuated by ten muscles in sagittal plane. The head, arm and torso (HAT) are modeled as a single rigid body. Interaction of the feet with the ground is modeled using a spring-damper unit placed under the sole of each foot. The path of each muscle is represented by a straight line. Each actuator is modeled as a three-element, Hill-type muscle in series with tendon. The governing equations of motion generated by the proposed method are equivalent to those developed with more traditional techniques. However the models can be more easily used in conjunction with control models of neuro-muscular function for the simulation of overall dynamic motor performance. In the proposed structure, segments can be easily added or removed. Such a model may have applications in clinical diagnosis and modeling of paraplegic patients during robotic-assisted walking.

Stability and Bifurcation Analysis of an Asymmetrically Electrostatically Actuated Microbeam

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Hadi Madinei ◽  
Ghader Rezazadeh ◽  
Saber Azizi
Keyword(s):  
Applied Voltage ◽  
Equilibrium Points ◽  
Pitchfork Bifurcation ◽  
Spring Model ◽  
Electrostatically Actuated ◽  
Proposed Model ◽  
Mass Spring Model ◽  
The Stability ◽  
Mass Spring ◽  
Two Degree Of Freedom

This paper deals with the study of bifurcational behavior of a capacitive microbeam actuated by asymmetrically located electrodes in the upper and lower sides of the microbeam. A distributed and a modified two degree of freedom (DOF) mass–spring model have been implemented for the analysis of the microbeam behavior. Fixed or equilibrium points of the microbeam have been obtained and have been shown that with variation of the applied voltage as a control parameter the number of equilibrium points is changed. The stability of the fixed points has been investigated by Jacobian matrix of system in the two DOF mass–spring model. Pull-in or critical values of the applied voltage leading to qualitative changes in the microbeam behavior have been obtained and has been shown that the proposed model has a tendency to a static instability by undergoing a pitchfork bifurcation whereas classic capacitive microbeams cease to have stability by undergoing to a saddle node bifurcation.

scholarly journals Advanced Metering Infrastructure with Secure Chord Lookup Protocol for IoT Systems

2021 ◽  
Vol 2 (3) ◽  
pp. 112-117
Author(s):  
Karrupusamy P
Keyword(s):  
Data Exchange ◽  
Production Capacity ◽  
Delivery Ratio ◽  
Advanced Metering Infrastructure ◽  
Package Delivery ◽  
Proposed Model ◽  
Computation Algorithm ◽  
Advanced Metering ◽  
Lightweight Authentication ◽  
Multi Mode

The advanced metering infrastructure is enhanced in terms of system storage and latency using a secure chord lookup protocol scheme. Privacy of the subscriber and data security is maintained while reducing the memory consumption and data exchange duration using a protected multi-mode computation algorithm in the proposed model. Internet of things (IoT) based advanced metering networks can be greatly benefitted by this model. The production capacity is increased by 25% using the proposed model as per the simulated results, when compared to the existing systems. There is also over 50% reduction in the average data collection time and 15% reduction in the package delivery ratio. Lightweight authentication based secure mechanism is also provided to improve the safety of the model. When compared to the existing algorithms, the memory requirement and utilization of the proposed model is reduced by half.

Analysis of Degenerate Bifurcation in Machining Using a Nonlinear Model

2001 ◽  
Author(s):  
M. S. Fofana ◽  
Satish Bukkapatnam
Keyword(s):  
Differential Equations ◽  
Degrees Of Freedom ◽  
Nonlinear Effects ◽  
Governing Equations ◽  
Bifurcation Theorem ◽  
Orthogonal Machining ◽  
Proposed Model ◽  
Nonlinear Delay Differential Equations ◽  
Delay Differential ◽  
Centre Manifold Theorem

Abstract We present a two degrees of freedom model of machining dynamics that compactly captures the nonlinear effects of regeneration, tool wear and plowing under orthogonal machining. Extensive simulation experiments show that the solutions to the governing equations of the model bear distinct similarities to signals from our earlier experiments, as reflected by both visual state portraits as well as the values of the quantifiers of a steady state dynamic system. Governing equations of the model lead to nonlinear delay differential equations, which we reduce to ordinary differential equations using Hopf bifurcation theorem and centre manifold theorem. Despite the ongoing efforts by the authors of this paper to quantify the simulations results analytically and experimentally, we strongly believe that our proposed model will be found to be amenable for studying and analyzing bifurcations that can lead to chatter in machining.

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